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The dissertation describes an Indigenous dream framework that underscores the significance of dreams as a mirror of trauma and a way that leads back to Indigenous knowledges. Significant differences of Western and Indigenous epistemology are exemplified by juxtaposing Western and Indigenous dream discourses. The selected prose fiction allows for a dream categorization that emphasizes the significance and meaning of dreams as a metaphorical as well as narrative device.
Nightmares/Anxiety dreams are often the result of the devastating effects of colonization and especially Residential School. Nightmares in the texts are often exact replicas of the abuse suffered in the boarding schools. They are discussed in the context of Robert Arthur Alexie’s novel Porcupines and China Dolls (2001/2009) represents dreams and traumatic nightmares and deals with the fictional Blue People First Nation. The community’s collective intergenerational trauma of Residential School experience keeps them stuck in dysfunctional dynamics dominated by suicides, sexual and physical abuse, drug and sex addictions.
Telling dreams, categorized as “instructing dreams,” and “announcing dreams,” teach the dreamer what will happen in the future. They are discussed in the context of Richard Van Camp’s short stories “On the Wings of this Prayer” and “The Fleshing” (Godless but Loyal to Heaven, 2012), which represent the category of the ecological nightmare as well as of telling dreams. Ecological nightmares display environmentally destructive effects of capitalist globalization that have come to “infect” the world. The Windigo figure in the stories serves as a manifestation of resource and in particular petro-capitalism and Western society’s constant need to subjugate nature. Ecological dreams hence call for ecological vigilance and establish Indigenous knowledges as a source of resurgence and restoration.
Existential dreams function as decolonizing tools that facilitate liberation. The thesis provides a literary analysis of Richard Wagamese’ novel Ragged Company (2008) and Cherie Dimaline’s short story “room 414” (Red Rooms, 2007) where homelessness is postulated as the manifestation of individual and tribal/communal disjointedness and isolation. Through existential dreaming, the urban lives of most of the characters dwelling in the shadows and margins of society are existentially transformed and healing seems possible. Paternalistic colonial mindsets continue to patronize Indigenous knowledges (as unreliable and unscientific) until Western “discoveries” prove what has been known for decades.
The thesis underscores dreams as an essential part of Indigenous Knowledges, i.e. as knowledge sources. Surmounting Western dream perceptions and instead valorizing Indigenous knowledges, the characters in the texts discussed in my thesis, unremittingly follow their dreams’ instruction and eventually achieve reconciliation and healing. In the fictional texts discussed, nightmares represent homelessness, trauma, stagnation, and a disconnection to one’s (Native) background, whereas dreams represent continuity through the restoration of identity, finding home, and a sense of belonging. The notion of a dream reality and a waking reality influencing and informing each other relies on sharing dreams with the community, eventually leading to an enactment of the dream or vision. Dreaming and identity are significantly linked and foster processes of intellectual self-determination. The characters’ inability to externalize their internal wishes, desires, and needs results in further denial and consequential bitterness that feed into the spiral of alcohol and drug abuse as well as metaphorical and literal homelessness. The dreams’ semantic field strongly alludes to ceremonial traditions and provides the prospect of a rooted Indigeneity. At the turning points in the lives of the characters, when dreams and visions start to appear, they are lost in translation. The characters’ own illiteracy towards Native epistemology and spirituality has them trapped in the inability to read and act on their dream messages. Strong (often female) Indigenous presences that go hand in hand with the appearance of dreams provide the protagonists with guidance and lead the way back to the “Old Ways.” Through dreaming, the spiral of colonialism is disrupted and replaced by the circle of reconciliation and relationality.
The aims of this study were to quantify the key mineralization processes and the resulting nutrient release potentials of different sediment types, their ranges of extent and dependency on varying environmental conditions such as seasonal variations or shifts in oxygen availability. Benthic phosphate fluxes and flux potentials were of particular interest as P is an essential nutrient for algal growth in marine systems and phosphate is often limiting primary production, hence strongly promotes the production of new biomass. A major P source in marine environments are mineralization products of early diagenetic processes.
To gain insight into the pathways of organic matter mineralization and subsequent secondary reactions, key reactants in the solid and the dissolved phase were considered in typical sediments of the Baltic Sea and the Black Sea. Seven study sites in the German Baltic Sea region, representative of the major depositional environments, including coarse and fine grained sediments, both rich or poor in organic carbon, were intensively studied. The investigations were conducted on a seasonal basis during ten ship-based expeditions between July 2013 and March 2016, covering spring- and autumn algal blooms, stagnation periods with bottom water hypoxia and winter dormancy. Hypoxic conditions frequently developed in the bottom waters of the Bay of Mecklenburg, Stoltera and the Arkona Basin sites, shallower stations like the Tromper Wiek, the Oder Bank and the Darss Sill were usually not affected by hypoxia. Increased nutrient concentrations in the bottom waters coincided with oxygen depletion. High salinity dynamics were observed in the bottom waters above the studied sediments, which were due to frequent salt water inflows from the North Sea. Bottom water temperature variability was seasonally conditioned.
The studied sands showed 2-3 orders of magnitude higher permeability values and about one order of magnitude lower organic matter contents compared to the studied muds. Occasionally, strongly increased organic matter contents were observed in the sands, likely induced by downward mixing of plankton bloom derived particles. The organic matter was found to be essentially supplied by marine phytoplankton, indicated by its elemental composition and isotopic signature.
Additionally, an adapted approach of the Keeling plot method was made to characterize the source material of organic matter mineralization. In marine environments, dissolved inorganic carbon concentrations often increase with depth together with an isotopic carbon signature shift to lighter values due to organic matter mineralization. The Keeling plot method was commonly used to determine the isotopic signature of carbon sources for ecosystem respiration. Conventionally, the influence of respiratory depletion of 13CO2 on the isotopic composition of the atmosphere was studied in terrestrial and limnic biogeochemistry. The same approach was applied on organic matter mineralization in sediments and the water column during this study. Mixing of bottom water derived background DIC and DIC released into the environment during organic carbon decomposition was assumed. In a modification of previous approaches, where changes in concentration and δ13C of DIC were followed over time, vertical profiles were analyzed in this study, which represent time-dependent variations superimposed by transport processes . DI13C gradients in the water column of the Black Sea and pore water profiles in the Black Sea and the Baltic Sea were used to estimate the 13C signature of the mineralized organic carbon via Keeling plot analysis. The Black Sea water column revealed a δ13C signature of the organic matter source close to the signature of typical particulate organic matter in the ocean and previously reported values for the Black Sea euphotic zone. In the pore waters of Black Sea sediments (from short and long sediment cores), Keeling plot analysis clearly demonstrates that the released DIC at depth can be derived from different sources. An isotopically very light carbon source (< –60 ‰) was associated with anaerobic oxidation of methane in the Black Sea. Marine organic matter was the principal source for DIC in the deeps of Baltic Sea basins, while the calculated carbon source isotopic signature in sediments of sand flats and bays was shifted to heavier δ13C signatures compared to marine organic matter. These shifts were attributed to potential dissolution of sedimentary carbonates or organic inputs of terrestrial C4 vascular plants like maize and other agricultural plants. The carbon source isotopic composition calculated via Keeling plot analysis correlated well with directly measured δ13C signatures of surface sediments POM.
Organic matter mineralization activity in the southern Baltic Sea sediments was studied via gross sulfate reduction rate analysis and total oxygen uptake measurements in sands and muds. Oxygen penetration depths were less than 4 mm in both, muddy and sandy sediments. Oxygen uptake rates were similar in muds (10.2 mmol m–2 d–1) and sands (10.7 mmol m–2 d–1), while significantly higher rates were measured in the coastal near sites of the Bay of Mecklenburg (about 12 mmol m–2 d–1) than in the deeper Arkona Basin (about 9 mmol m–2 d–1). Substantial sulfate reduction was measured in the muddy (about 4 mmol m–2 d–1) and the sandy (about 1 mmol m–2 d–1) study sites. Highest sulfate reduction rates (4.4 – 5 mmol m–2 d–1) were detected in the muds of the Bay of Mecklenburg during summer, about twice as high as in the Arkona Basin muds. Increased mineralization activity of the coastal near muds of the Bay of Mecklenburg is attributed to enhanced input of fresh organic matter during algal blooms.
About twofold higher oxygen consumption and sulfate reduction rates were measured in summer compared to winter in sandy and muddy sediments.
The studied sites were usually characterized by a typical biogeochemical zonation with oxic, suboxic and sulfidic zones. The concentration profiles in the muds reflected sulfate reduction and secondary redox-reactions, liberating dissolved carbon, nitrogen, phosphorus and hydrogen sulfide into the interstitial waters. Orders of magnitude lower concentrations were detected in the sands, while their top centimeters were mostly irrigated and mineralization products only accumulated below.
A several centimeter thick suboxic zone was sustained by active downward transport of oxidized material in the southern Baltic Sea coastal sediments, presumably mainly through bioturbation. Especially sulfur and iron species were involved in the secondary reactions between the metabolites of early diagenetic processes occurring in the suboxic zone. Partly high temporal variability was observed in the form of vertical migration of the sulfidic zone and a corresponding expansion and shrinking of the suboxic zone. The Arkona Basin site showed the most stable geochemical zonation over time, while the Luebeck Bight site and especially the Mecklenburg Bight site showed striking dynamics. The consequent redox-regime shifts within the surface sediments might promote mineralization of organic matter as higher sulfate reduction rates and higher total oxygen uptake were measured in these more dynamic muds. The vertical shifts of the redox-gradients can largely be explained by temporal and spatial variability of bioturbation activity, but also anthropogenic activities may play a role. Bottom trawling, may be the dominant mixing process at the Mecklenburg Bight site.
In the sands, less reactive iron and manganese contents were available compared to the studied muds, which may be due to frequent irrigation of the top centimeters leading to a loss of pore water reservoirs like dissolved Fe and Mn.
Another mixing process, storm induced sediment resuspension, was suggested to be important for the sediments in the study area. A severe sediment resuspension event at the silty Tromper Wiek site was indicated by steep gradients in pore water concentration and particulate mater content profiles in the top ∼ 5 cm sediments. Carrying out non steady state modeling (Bo Liu, IOW), the successive re-development of the pore water profiles towards a steady-state was simulated and the time span necessary to establish measured pore water profiles after the sediment disturbance event was approximated. In the predicted time span, daily average wind speeds reached an annual high of the category ‘gale’ which was probably sufficient to resuspend and irrigate the surface silt-type sediments.
This study showed that sediment mixing processes have a strong influence on early diagenetic reactions, solute release potentials and actual fluxes from the sediments. Also the sediment mixing via bottom trawl fishing can be regarded as an event-like disturbance. The newly developed approach of non-steady-state modeling of pore water sets (Bo Liu; IOW) can help to answer the question, how long it takes to reach a steady-state after a sediment disturbance event.
The concentration profiles in interstitial waters were used to calculate net transformation rates via the transport-reaction models REC and PROFILE. The calculations revealed net release of H4SiO4 and PO4 within the top 20 cm of the studied muds, while net DIC and NH+4 consumption and sulfate production was clearly evident within the top ∼ 5 cm. Intensive reoxidation of sulfide that was produced via sulfate reduction was also indicated by large deviations between the modeled net sulfate transformation rates and experimentally derived gross sulfate reduction rates. These surface near transformations were probably associated with microbial chemosynthesis.
The studied sands of the southern Baltic Sea were usually characterized by very low pore water gradients, probably due to their frequent irrigation. Accordingly, calculated transformation rates were one to two orders of magnitude lower in the studied sands compared to the muds of the southern Baltic Sea. However, during a situation with a stratified water column, substantial pore water reservoirs with the typical concentration trends were present in the sandy Darss Sill sediments. Integrated production rates of PO4, Mn2+ and H4SiO4 derived from these concentration profiles were in the same order of magnitude as in the muddy Arkona Basin.
Intensive pore water irrigation is also capable to transport fresh organic matter into the sediment as was occasionally indicated by strongly increased surface near TOC in the sands. Considerable gross sulfate reduction rates and total oxygen uptake rates were measured in the sandy Oder Bank sediments, where pore water concentration profiles rather suggested absence of diagenetic processes. The studied sands were, hence, not unreactive substrates but usually rather unable to preserve the mineralization products.
This reflects the often limited significance of pore water evaluations in irrigated sandy sites but also the high mineralization potentials of coastal sands. Early diagenetic processes and the impact of intense benthic-pelagic exchange in such shallow marine environments is still poorly understood, as they were rarely investigated in the past and are methodologically more difficult to investigate.
The Baltic Sea deeps Gotland Deep and Landsort Deep were mainly controlled by sulfate reduction and shallow anaerobic oxidation of methane. Calculated rates of net sulfate reduction and net sulfide production were equivalent, indicating a lack of sulfide re-oxidation reactions. Phosphate liberation rates were low in the surface sediments, but strong linear concentration gradients indicated liberation at depth.
The euxinic Black Sea sediments were purely controlled by sulfate reduction via anaerobic oxidation of methane at the sulfate-methane transition zone in sediment depths of up to several meters. Subsequent diffusive concentration gradients clearly dominated pore water profiles in the surface sediments.
Benthic solute reservoirs of the top 10 cm pore waters were generally higher in the muds than in the sands of the southern Baltic Sea. The smaller reservoirs in the sands were cause by intensive exchange between pore water and bottom water in these permeable sediments. The three studied muddy sites of the southern Baltic Sea showed great dissimilarities with respect to their pore water compositions. Large observed pools of dissolved Fe2+ and PO4 clearly point to reduction of reactive Fe and release of adsorbed P pools. Multi-dimensional scaling analysis showed that seasonal variability played only a minor role for the observed variability of the benthic solute reservoirs. Principal component analysis revealed that the studied sediments can be characterized by essentially two factors based on their pore water reservoirs of the top 10 cm: 1) their mineralization and accumulation efficiency and 2) their secondary reactions in the suboxic zone, reflecting fundamental differences in their sedimentation conditions and mixing processes. While the sands were similar to each other due to their overall low reservoirs, sands, silts and muds mainly differed in their mineralization and accumulation efficiency. Large variability was also observed within the studied muds regarding their predominating redox metabolites. Highest dissimilarities were evident between the neighboring sites Mecklenburg Bight (mostly suboxic) and Luebeck Bight (mostly sulfidic). Therefore, the biogeochemical state in the studied sediments were shown to be mainly controlled by their sediment type and the transport of reactive iron into the sediments. The supply of organic matter to the sea floor controlled the overall mineralization activity, while the sediment permeability determined the accumulation efficiency of the sediment. Mixing of surface sediments together with the complex relation of oxygen, sulfur, iron and phosphorus in the solid and aqueous phase is controlling benthic nutrient fixation/liberation reactions. Salinity variability showed no noticeable effects on early diagenetic processes. During four sampling occasions in the Arkona Basin, bottom water salinity showed strong variability which was also effecting pore water concentration profiles in more than 15 cm depth. However, concentration profiles of typical organic matter mineralization products remained remarkably stable. Also gross sulfate reduction rates seemed to be unaffected by the variable pore water sulfate concentrations.
Nutrient fluxes across the sediment-water interface were obtained by the interpretation of vertical pore water concentration profiles via different models (diffusive fluxes) and via incubation of intact sediment cores (total fluxes). Benthic diffusive fluxes represent potential release of solutes into the water column. They were often strongly associated with the benthic reservoirs, thus fluxes were highest in the muds, considerably lower in the organic-poorer silts, and generally close to zero in the sands. The dissimilarities between diffusive fluxes in the different sediments were mainly controlled by the sediment type. Highest variability was observed within the muds, controlled by their different diagenetic pathways due to different sediment mixing intensities.
In the muddy sediments, diffusive PO4 fluxes were much higher than mineralization of organic matter with the common element ratios of marine organic matter can provide, indicating active recycling of phosphorus within the muds due to recurring adsorption and re-release on reactive iron oxyhydroxide phases. Especially in the strongly mixed Mecklenburg Bight sediments, pore water dissolved PO4 was primarily controlled by the release of adsorbed P. Actual PO4 release into the bottom waters (determined via core incubation experiments) was only measured under extended bottom water oxygen deficiency conditions. The same applied to the redox-sensitive solutes Fe2+, Mn2+ and sulfide.
For the less redox-sensitive solutes, diffusion usually accounted only for a fraction of the total interfacial flux. The proportion of advective to diffusive transport was estimated with different methods. Bioturbation induced sediment mixing was quantified by comparing the diffusive H4SiO4 fluxes derived from pore water modeling with the total fluxes derived from the core incubations. The studied muds showed infauna induced advection proportions of about 35 – 100 %. Only when infauna was absent, diffusion became the dominant transport process across the sediment-water interface. In the studied sands, advection was the dominating transport process, since their generally low surface near reservoirs lead to diffusive fluxes close to zero. However, it remains unclear whether bioturbation or hydrodynamic irrigation are responsible for that. An attempt was made to estimate the effect of hydrodynamic irrigation for a range of reasonable bottom water velocities from the sediment bedform geometry after Neumann et al. (2017). However, resulting potential hydrodynamic irrigation was found to be rather low compared to reported values from the literature and may significantly underestimate actual irrigation of the sandy sediments.
In a new non steady-state multi-element diagenetic modeling approach (Bo Liu, IOW), vertical δ13C pore water profiles were used to estimate the significance of advective transport processes. Mixing processes at the sediment-water interface were expressed as multiple of pure diffusion (ε). By adjusting this mixing coefficient as boundary condition for best fits of predicted to measured pore water profiles, the degree of these mixing processes was estimated. In the Arkona Basin surface sediments, this approach revealed best fits assuming a mixing depth of 3.5 cm with a tenfold higher total mixing degree based on diffusional transport. The calculated mixing depths and intensities were similar to bioturbation depths and rates obtained via traditional methods (Morys, 2016). The novel modeling approach is a promising method to evaluate surface sediment mixing processes.
Increased mineralization activity during productive seasons lead to increased oxygen consumption and therefore frequent bottom water hypoxia. The effects of hypoxic bottom water conditions on the early diagenetic processes in the sediments were studied via prolonged core incubation experiments. Shifts to bottom water oxygen deficiency had various consequences for benthic reservoirs and fluxes. The oxygen consumption decreased during hypoxic incubation phases. Decreased bioturbation activity diminished advective transport so that total fluxes of redox-insensitive solutes (e.g. H4SiO4) were decreased. Reactive iron and manganese oxides act as barrier (“iron curtain”) in the suboxic zone, preventing redox-sensitive solutes from their release into the water column. After a shift to bottom water hypoxia, these reactive oxides are re-dissolved and liberated into the water column. Prolonged incubation experiments suggested that the Mn-oxide reservoirs were depleted first before the Fe-oxides with the adsorptively bound phosphate were liberated.
The release of nutrients (especially phosphorus), dissolved inorganic carbon, and redox- sensitive compounds (e.g. hydrogen sulfide) strongly varied in the different studied environments, covering coastal-near oxic, temporary hypoxic and euxinic conditions.
In environments, where advection through hydrodynamic irrigation or bioturbation do not occur, like in anoxic or euxinic systems, surface-near pore water gradients reflect total solute interfacial fluxes. They depend on the supply of organic matter to the sea floor, the mineralization rates in the sediments and the composition of the overlying bottom water. In the Black Sea, much of the organic matter mineralization was performed already in the water column and not in the sediments, leading to a decreasing export of organic matter to the sediment and increasing concentrations of mineralization products in the bottom water with increasing water depth. Accordingly, benthic fluxes across the sediment-water interface of the deep Black Sea sites were the lowest of the entire study, essentially reflecting the low mineralization rates of AOM in deeper layers. Highest fluxes in the Black Sea were observed at the continental slope at intermediate water depths, but were still lower than in the Baltic Sea deeps.
In contrast, highest DIC fluxes were detected in the oxygen depleted Baltic Sea deeps Gotland Deep and Landsort Deep. These basins are shallow enough that reactive organic matter reaches the sea floor, where it is mineralized via sulfate reduction close to the sediment surface. Strong concentration gradients and therefore high diffusive interfacial fluxes across the sediment-water interface were evident. As bioturbation was absent, these diffusive fluxes were representative for total interfacial fluxes unlike in sediments with additional advective flux components.
In more complex environments, like coastal oxic sediments, inhabited by macrofauna, overflowed by currents and affected by resuspension events, the sediment surface represents an interface between turbulent and calm conditions, high and low concentrations and/or different redox-states. Such gradients are the basis for intensive exchange processes. The surface sediments in the coastal sites of the southern Baltic Sea were characterized by active organic matter mineralization via sulfate reduction and mixing induced secondary reactions taking place in the suboxic zone. This included the removal of dissolved sulfide due to iron oxide reduction with simultaneous liberation of PO4 into the interstitial waters. High surface near P reservoirs existed due to internal P cycling within the sediments, which was in turn driven by continuous re-oxidation of the reduced iron by downwards transported oxygen. These reservoirs were only actually released into the water column during bottom water oxygen deficiency situations, when the iron re-oxidation was inhibited.
This also applies for sediments of the Gulf of Finland and the deeper Baltic Sea basins Bornholm Basin and Gdanks basin, where temporary hypoxic conditions are responsible for recurrent benthic phosphate release.
The widespread occurring phosphate adsorption on sedimentary solid iron phases is a much debated ecosystem service of marine sediments. As discussed in this work, the sedimentary P liberation rates and pools of readily bio-available dissolved phosphate can be substantial in Baltic Sea muddy sediments. Actual phosphate fluxes across the sediment-water interface, though, are relatively small because phosphate is scavenged by adsorption on iron oxyhydroxides that are usually an integral part of coastal marine sediments if overlain by oxic bottom waters. Although muddy sediments often show only an oxic layer of only few millimeters thickness, adsorption capacities of iron oxyhydroxides are large enough to substantially retain P from being liberated into the water column. Falling under reducing conditions, iron oxyhydroxides are re-dissolved, liberating high amounts of PO4 into the surrounding waters. While permanently oxic sediments will preserve adsorbed P, permanently anoxic sediments steadily release mineralized P into the water column. However, sedimentary environments of oscillating redox conditions are predestined for high, burst-like benthic P fluxes. Especially in a quasi isolated environment like the Baltic Sea, with high nutrient inputs but only few sinks, these internal recycling processes promote eutrophication in the long-term. Further expanding hypoxia and anoxia in the Baltic Sea with a subsequent loss of benthic fauna and altered nutrient dynamics in the surface sediments may be the consequence.
Coastal and marginal seas – like the Baltic Sea – serve as natural reaction sites for the turnover and accumulation of land-derived inputs. The main location for the modification and deposition of the introduced material is, in most cases, not the water mass, but the sediment. Its key function as central reactor in the interaction between land and sea has so far been insufficiently studied and assessed. This study was part of the interdisciplinary SECOS project that aimed to identify and evaluate the service functions of sediments in German coastal seas in the context of human use with a focus on the Baltic Sea. One of its goals was to assess sediment functions related to the intermediate storage or final sink of imported material like nutrients and contaminants, and quantify their inventory as well as their mass accumulation rates on multi-decadal to multi-centennial time scales. For that, a detailed examination of the natural and anthropogenic processes that interfere with sediment accumulation in the south-western Baltic Sea basins is essential.
The “East German National Park Programme” of 1989/1990 was considered a coup de main, resulting in the immediate protection of 4.5% of the GDR’s territory. The authors of this programme later described the approach and its success as “using a window of opportunity during the transition phase of state and nation.” This leads to the question whether a state’s transformation period constitutes a preferred time frame and momentum for spatial conservation success.
Conservation efforts in Azerbaijan showed a similar success as the East German National Park Programme. In a country with the highest biodiversity in Europe, increasing the share of protected land from 5.0 % in 2001 to 10.3% in 2015 constitutes a remarkable achievement. Thus, the country became an interesting case study regarding the question whether “hot moments for conservation” exist in times of political and governmental changes, and if spatial success in nature conservation can be linked to political transformation. This thesis attempts to identify how the protected area (PA) network in Azerbaijan could be expanded by 100%, what achievements were made, and what conditions still need to be met for the quantitative and qualitative improvement of the PA network. To this end, I consider this increase under landscape-ecological, historical and institutional aspects. The local culture and political pre-sets in the country present additional issues for analysing the past 25 years of nature conservation in Azerbaijan.
Foot-and-mouth disease virus (FMDV) is a positive-sense RNA virus of the family Picornaviridae that comprises of seven serotypes and is distinguished by a high contagiosity with the ability of rapid spread. Strategies for abatement and control are based on an early detection, quick initiation of retaliatory actions and mass vaccinations. Therefore, aim of the study was the development of a fast and easy method for genome sequencing as well as an investigation into the causes, why some cell lines that are mainly used for vaccine production, are resistant towards FMDV infection. Finally, adaptive sequence changes in different cell culture systems and associated effects on particle stability and immunogenicity were examined.
In case of an outbreak it is of major importance to detect and rapidly characterize the circulating virus isolate to choose an appropriate vaccine to minimize the viral spread. In addition, comprehensive genome analysis of the outbreak strain provides information about the origin of the virus and allows molecular epidemiology. A universal primer set, covering most parts of the open reading frame of the viral genome, was developed to perform quick sequence analyses, independently of the viral serotype (Paper I). Especially in endemic regions, vaccination of susceptible animal species is the main action to combat foot-and-mouth disease (FMD) in an acute outbreak situation as well as a preventive measure. Reasons, why some baby hamster kidney (BHK) cell lines are resistant towards an infection with FMDV, were examined in a second study that narrowed down the cause for this phenomenon to an impaired attachment of the virus to the cell surface. Furthermore, an alternative approach could be developed to successfully adapt the virus to the resistant vaccine-production cell line by using a FMDV-sensitive “wet-nurse” cell line (Paper II). Adaptive changes in the capsid-coding region of the viral genome caused through cultivation and passaging of the virus in different BHK cell systems were the topics of the third study. It was shown that capsid alterations are rather serotype-specific and dependent on the cell line used than influenced by the cell media. Viral titers and neutralization profiles of the adapted isolates were not affected compared to the original viruses (Paper III).
Overall, this work expanded our knowledge on the control and eradication of FMD and will support the global effort to combat the disease.
Since its introduction in 2006, the NOD/scid mouse model has greatly contributed to the understanding of the pathomechanisms of antibody-mediated thrombocytopenia. This progress has however been hampered by inter-laboratory differences. With this work, we make several suggestions to minimise these differences:
We suggest that human platelets (blood group 0) be injected into the mice (age- and sex-matched, 8-16 weeks) via the tail vein. For antibody injection, scientists may choose between intraperitoneal and tail vein injection, each of which has strengths and drawbacks. In case of low antibody titer or low avidity antibodies, preincubation of the platelets with the patient serum prior to injection promotes platelet elimination where standard protocols fail. For subsequent sample preparation, we found that newly-launched ready-to-use kits present a good alternative to classical density gradient centrifugation by reducing man-hours and turnover time without affecting the quality of flow cytometry analysis.
In a second part, we used the revised mouse model to study anti-CD36 mediated thrombocytopenia in vivo. Anti-CD36 antibodies have been suggested as frequent case for FNAIT in Asia. The mechanisms behind this remain partly unclear. After injecting anti-CD36 monoclonal antibody or anti-CD36 patient immunoglobulin into the system, circulating human platelets were rapidly cleared. Interestingly, the polyclonal patient immunoglobulins used were not uniform in their anti-platelet reactivity. On further examination, we found that the anti-CD36 antibodies induce platelet activation and aggregation, which we were able to inhibit by the addition of an Fcγ-receptor blocking agent. This suggests a possible role for Fcγ-receptor in the activation and elimination process.
As our results from the experiments on the role of complement in the elimination process are however ambiguous, further studies are needed. The clinical relevance of anti-CD36 antibody-mediated platelet activation and aggregation for the high abortion rates in affected women has yet to be evaluated.
This work examines the influence of monovalent and divalent cations on tetramyristoyl cardiolipin (TMCL) monolayers. A lipid monolayer can undergo an ordering transition of the lipid alkyl chains from a disordered fluid phase (liquid-expanded (LE)) to an ordered gel phase (liquid-condensed (LC)). Compression of the lipid monolayer in a Pockels-Langmuir trough was monitored with a Wilhelmy plate tensiometer, yielding the surface pressure π in dependence of the area a molecule can occupy on average A, as a π-A-isotherm. The onset of the first order LE/LC phase transition is marked by an abrupt change in the isotherm at surface pressure πc.
These associated lipid membrane changes were characterized by variation of the compression speed, kind and concentration of the monovalent and divalent salt, pH, and temperature. The CL monolayer phase transition was found to depend on the compression speed, yielding only a small variation in the compression isotherms.
For monovalent cations on the cardiolipin monolayer, the dependence on salt concentration of the lipid liquid gel phase transition surface pressure πc was determined and a non-monotonic behavior was found, with a maximum in πc for a salt concentration of 0.1 mol/l. The maximum in πc can be shifted with pH (e.g. pH = 4.2). This behavior extended to potassium, sodium and cesium cations in the subphase. No ion specific effects were observed, which pointed to the prevalence of electrostatic interactions in the system.
Different divalent salt subphases, of either magnesium, calcium, strontium, manganese, iron or zinc salts, with fixed sodium chloride concentration of 0.15 mol/l at pH of 5.8 and 25 °C were investigated. πc decreases upon addition of divalent salts to the subphase. This points to increased screening and binding effects. Strongest binding effects were observed for calcium and manganese cations.
The electrostatic interactions of the system were modeled with a mean-field theory: Grahame’s equation, and a simple law of mass action. CL is modeled at half its molecular area and half its charge, with a proton dissociation constant of the phosphate group Ka,intrinsic(PO4) = 0.1 mol/l. The agreement with the experiment was satisfactory.
A linear dependence of πc on the temperature was found for cardiolipin monolayers on all subphases. The isothermal area compressibility modulus KA is calculated from selected isotherms. It was found that the flexibility of the monolayer decreases with temperature and the area per molecule for the cardiolipin fluid phase.
The compression speed, monovalent salt concentration, pH, and selected divalent cations were investigated with the BAM. For all a sigmoidal growth of xgel with compression was observed. For high salt concentrations non-circular and dendritic domains were observed.
A simple model for the nucleation process was introduced, yielding an estimate of 20 nm for the critical domain radius, which is below the resolution of the BAM, but a common length scale in biological systems.
Certain basal Teleostei from the Early Jurassic of Mecklenburg-Western Pomerania (Germany) and the Late Jurassic of the Franconian Alb (Bavaria, Germany), the Swabian Alb (Baden-Württemberg, Germany) and the western Jura-Mountains (Ain, France) are described. The present doctoral dissertation includes four studies, dealing with representatives of “Pholidophoriformes”, Leptolepidae and Orthogonikleithridae. These studies include anatomical descriptions of new taxa and reviews of poorly known fishes. Furthermore, the stratigraphic and palaeobiogeographical distributions of the examined taxa are discussed.
Costs of reproduction. A demographical approach to examine life-history trade-offs ─ Abstract. Resource-allocation trade-offs are fundamental constraints of life-history evolution. In particular the trade-offs between reproduction and longevity and between present and future reproduction are expected to form reproductive patterns. Unfortunately, exploring such trade-offs in natural populations is complicated and may not be possible. In face of several limitations, zoo data appear to be useful to better understand the reproductive biology of endangered, rare or cryptic species. In the first step, it was sought after with a data-mining, comparative multi-species approach for broad patterns of correlations between lifespan and variables in bird-eating spiders (Theraphosidae). The subfamily Eumenophoriinae on average lived longest, followed by the Theraphosinae, Ornithoctinae, Grammostolinae, Selenocosmiinae, Ischnocolinae and finally the Avicularinae. Species inhabiting tropical, more humid and/or low-altitude environments lived longer, suggesting that more predictable environments favour the evolution of longer lifespans. Furthermore, large range size, low abundance, sub-terrestrial life-style, and aggressive behaviour were all linked with longer lifespans. An argument for resource allocation trade-offs was found as larger spiderling and prosoma size were negatively related to longevity. In the second step, a demographical approach has been applied for two old-world deer species (Vietnamese sika deer Cervus nippon pseudaxis, Mesopotamian fallow deer Dama dama mesopotamica). In both species, births peaked right before the onset of the rainy season in natural environments. Females reached high reproductive output earlier in life and had (in one species only) higher survival rates than males. Offspring number covaried positively rather than negatively with longevity. In females, the length of the reproductive phase correlated positively with longevity, birth rate within the entire lifespan, and offspring number, while it was negatively correlated to the birth rate during the reproductive phase (in one species). The length of the post-reproductive phase was positively related to longevity and negatively to birth rate during the entire lifespan. In the third section, life-histories of Asiatic (Equus hemionus ssp.) and African wild asses (Equus africanus ssp.) have been anlaysed in a comparative way with another demographical long-term approach. All taxa showed even in captivity peak birth rates during the periods of highest food availability in their natural environments. Sex-specific survival rates with females living longer than males were evident in Kulan and Onager but not in Kiang and Somali wild ass, pointing towards different life-history strategies even among closely related taxa. Females achieved their highest reproductive output earlier than males, which is typical for polygynous mating systems. Offspring number and longevity were rather positively correlated than negatively. Taken together evidence for reproductive trade-offs was weak, though the length of the reproductive period was negatively related to birth rates within the reproductive period. Birth intervals increased with female age, probably reflecting detrimental effects of senescence.
Quang Xuong is considered as one of the most developed districts in Thanh Hoa Province in terms of agricultural. The major purpose of this research is to find good places to suggest for annual crops production in the case study. Therefore, the assessment of land potential productivity, land suitability, and land cover/land use change in different periods is essential for making strategies of sustainable agricultural development as this will help land-users and land managers to discover the potential and limitations of the current existing land conditions to make appropriate policies and plans for future land use. Its results will provide basic information to make reasonable decisions for investments and rational reclamations of cultivated land before and after each crop season in order to meet the objectives of sustainable development in terms of economic efficiency, social acceptability, and environmental protection. The research site is located at latitudes 19 degree 34 minute N - 19 degree 47 minuteN and at longitudes 105 degree 46 minute E - 105 degree 53 minute E. The total area is about 227km2; in which 128km2 is in use for agricultural activities. Based on soil classification methods by FAO-UNESCO (1988), the agricultural land is classified into six main soil groups, including Arenosols, Salic Fluvisols, Fluvisols, Gleysols, Acrisols, and Leptosols, 12 soil units and 18 sub-units. The largest area belongs to the Fluvisols group with 9358.29ha and the smallest area is identified as the Leptosol group with 219.33ha. Most of the soil in this district has low to moderate nutrition, but in general, they are still suitable for agricultural production. There are 42 land units defined in the land mapping, which can be different from each other by one or more land characteristics. The land mapping unit is created from the overlay of all thematic maps of soil chemicals, soil physical characteristics, and relative topography together by application of GIS techniques. It presents land characteristics and properties in this case study and will be used in comparasion with a particular crop requirement for growth in land suitability evaluation process. A certain land unit may be suitable for one or more types of different land use. It is also classified as highly suitable for a specific land utilization type, but less suitable or unsuitable for other crops. For example, in this study, land unit 26 is determined as highly suitable (S1) for growing paddy rice and maize, but it falls into moderately suitability (S2) for groundnut crop by using parametric (square root) method used in this thesis. Depending on the kind of crops need to be evaluated and its requirement for development compared with each land unit characteristics, land-users will determine the best suitable place for crop production. Identification of land use change in different periods of time has become a central key to monitoring of land resources. It is relatively important for effective land management to protect the land resources, especially the land used for agricultural production from overuse and environmental changes. The sprawl of inhabitant areas, development of rural infrastructures, and industrialization are responsible for serious losses of agricultural land. In this study, remote sensing techniques were applied to studying the trends of land cover change in the abovementioned district in a period of about 24 years from 1989 to 2013. ArcGIS software was adopted to develop the land cover and the change of land use maps from 1989 to 2013. Two satellite images with moderate resolution were collected from USGS Earth Explorer website, Landsat5 TM for 1989 and Landsat8 OLI & TIRS for 2013. After image geo-processing, the images were classified into six land cover categories by applying supervised classification method (Maximum Likelihood). The six main obtained land cover types were built-up areas, agricultural land, forest land, water surface area, salty land, and unused land. The overall accuracies of land cover maps for 1989 and 2013 were 94.08% and 92.91%, respectively. The results of change detection analysis indicate that the cultivated, water surface and unused lands decreased by 22%, 17%, and 91%, respectively. In other side, the built-up and salty land increased by 78%, 58%, respectively and forest land increased from 52.69ha in 1989 to 395.76ha in 2013. The assessment of land potential productivity for agricultural production and land suitability for selected annual crops was based on FAO guidelines for land evaluation (FAO, 1976, 1985, and 1993) which were adopted and slightly modified for compatibility with Vietnamese conditions. All related data were stored, analyzed, mapped and presented in ArcGIS software. Weighted Linear Combination Method developed by Hopkins (1977) and GIS techniques were used to analyze and determine the land potential for agricultural use in the study area. The results show that 5.26%, 83.10%, 10.06%, and 1.57% of the investigated areas were assessed as high potential, moderate potential, low potential and very low potential for growing crops. Regarding land suitability evaluation, the simple limitation, parametric (square root), and AHP methods were used to evaluate the suitability levels for selected crops, including paddy rice, sweet potato, groundnut, maize, potato, sesame, soybean, and green pepper. The obtained results indicate that each applied method provides different results of land suitability level for a specific crop in certain land units compared to the other two methods, and OM, soil pH, soil texture, and relative topography were found out as the main limitation factors which affected land suitability level. The study also suggests that three different methods as abovementioned can be expanded and applied in other places with the appropriate factors used for land suitability evaluation according to particular area conditions.
This thesis highlights the impact of surface charges and negative ions on the pre-ionization, breakdown mechanism, and lateral structure of dielectric barrier discharges operated in binary mixtures of helium with nitrogen or electronegative oxygen. Sophisticated diagnostic methods, e.g., non-invasive optical emission spectroscopy and the electro-optic Pockels effect as well as invasive laser photodetachment and laser photodesorption, were applied at one plane-parallel discharge configuration to investigate both relevant volume and surface processes. Moreover, the experimental findings were supported by numerical fluid simulations of the discharge. For the first time, the memory effect of the measured surface charge distribution was quantified and its impact on the local self-stabilization of discharge filaments was pointed out. As well, it turned out that a few additional seed electrons, either desorbed from the charged dielectric surface or detached from negative ions in the volume, significantly contribute to the pre-ionization resulting in a reduced voltage necessary for discharge breakdown. Finally, effective secondary electron emission coefficients of different dielectrics were estimated from the measured breakdown voltage using an analytical model.
A large portion of the earth's surface is covered with various vegetation classes (i.e. grassland, wetland and agricultural area, forest) of many diverse species and canopy configurations. The ability to assess and to monitor canopy parameters, such as biomass, leaf area index, and vegetation water content, is of vital importance to the study of different agronomic processes. Remote sensing techniques provide a unique capability towards probing different vegetation types and canopy by operating at different bands, observation angle etc. Over the past decades, significant progress has been made in remote sensing techniques of land processes specially vegetation characteristics through development of advanced ground-based, airborne and space-borne microwave sensors, methods and approaches such as theoretical, semi-empirical and empirical models, needed for analyzing the data. These activities have sharply increased in recent years since the launch of different active and passive satellites and sensors. Remote Sensing (RS) science and techniques combined with ground truth data can provide new tools for advanced agricultural crop applications. It has been demonstrated that RS has the ability to estimate biophysical parameters of agricultural crops over time at local, regional, and global scales. In this study, RS images in visible/near infrared (VIS/NIR) domain as well as microwave domain combined with ground truth data were used to assess biophysical parameters of agricultural crop during their whole growing season at Durable Environmental Multidisciplinary Monitoring Information Network (DEMMIN) test site in North East Germany. Ground truth studies were carried out for 31 weeks during 17th April – 13th November 2013 over three crop lands including winter wheat, barley and canola. Landsat 8 OLI, Landsat 7 ETM+ were used for the VIS/NIR studies and TerraSAR-X synthetic aperture radar (SAR) images were used to study biophysical parameters of agricultural crops in microwave part of electromagnetic spectrum. The analysis was conducted by calculating different vegetation indices (VIs) to estimate the biomass (fresh and dry), LAI, and vegetation water content (VWC) of three crops using Landsat 8 OLI and Landsat 7 ETM+ combined with ground truth data. A new concept of Soil Line retrieval from Landsat 8 image was also developed to estimate plant biophysical parameters using soil line related vegetation indices in optical domain of electromagnetic spectrum. Different approaches including univariate, multivariate stepwise regression and semi-empirical water cloud model was also used to estimate the biophysical parameters of agricultural crop using TerraSAR-X data in microwave domain of electromagnetic spectrum. Perhaps the most important conclusion of this study is that the RS approach can provide useful information about estimating agricultural crop parameters over time and local scale, which can therefore provide valuable information to aid the agronomy community.
Numerous signalling pathways orchestrate the development, the functions, and the survival of cells, mostly in response to external stimuli. An overwhelming amount of data supports the concept of specific, spatio-temporal redox signalling pathways that affect the redox state of protein cysteinyl side chains and thus the biological function of these proteins. Glutaredoxins (Grxs) and thioredoxins (Trxs) catalyse reversible thiol-disulphide exchange reactions. The cytosolic Grx2 isoform Grx2c is essential for brain development and axonal outgrowth. A reversible dithiol-disulphide switch of CRMP2 has been identified as one of the major targets regulated by Grx2c. This CRMP2 redox switch is toggled in neuronal differentiation. Reduction of CRMP2 thiols induces profound conformational changes, modifying interactions and downstream elements of this redox switch. In [article I] and [manuscript V], we identified the Cys504 of CRMP2 to be the redox regulated residue. We used various in vitro assays with recombinant protein and molecular dynamics simulations to characterise the conformational change. The changes involve the solvent accessible surface area of at least one known phosphorylation site at the C-terminus of the protein. In [article III], we analysed the function of Grx2 and Trx1 in a model for perinatal asphyxia. Trx family proteins exhibit a very complex, cell-type and tissue specific expression pattern following hypoxia/ischemia and reoxygenation, especially Trx1 and Grx2. The results imply the clinical relevance for both proteins in perinatal asphyxia as well as many other neurological disorders. In agreement with the results presented in [articleI], Grx2 may be required for the re-establishment of neuronal integrity and connectivity. Cell shape, all forms of intracellular transport, and cell movement depend on the cytoskeleton, particularly on the fine tuned complex regulation of the dynamic re-arrangement of actin filaments and microtubules. In [article IV], we discuss the redox regulation of this dynamic cytoskeletal remodelling. Taking recent discoveries into account, we focus on redox signalling mechanisms, e.g. reversible thiol and methionyl switches. These switches are specifically controlled by enzymes such as Trx1 and Grx2c, for instance, and not the result of random modification by unspecific oxidants. Methionyl sulphoxidation of actin can be reversed by methionyl sulphoxide reductase (MsrA), promoting actin polymerisation. Human cells express two different Msr enzymes (MsrA and MsrB), that can reduce S- and R-methionyl sulphoxide, respectively. In the gram-positive Streptococcus pneumoniae, on the other hand, both Msr genes and thus enzymes were fused during evolution. In [article II], we characterised the surface-exposed thioredoxin family lipoproteins Etrx1 and 2 and regulators of this Msr (SpMsrAB). A loss of function of both Etrx proteins or SpMsrAB dramatically reduced pneumococcal virulence, enhanced the bacterial uptake by macrophages, and accelerated pneumococcal killing by H2O2 or free methionine sulphoxide. Identification and characterisation of components of this redox regulated system may contribute to the design of new antimicrobials. In [manuscript VI], we investigated the effects of Grx2c expression on cell morphology, migration, and invasion behaviour of cancer cells. Grx2c expressing cancer cells developed dramatic changes in phenotype, including alterations in cytoskeletal dynamics and significantly increased motility and invasiveness. We used quantitative proteomics and phopshoproteomic approaches to characterise the underlying mechanisms. Proteins and pathways regulating cytoskeletal dynamics, cell adhesion, and receptor-mediated signal transduction were detected to be specifically altered. We started a clinical pilot study with patients suffering from clear cell renal cell carcinoma (ccRCC). Grx2c was expressed with significantly higher frequency in ccRCC compared to healthy kidney tissue, associated with a strong trend for locally more advanced tumour stages and a clear tendency for a decreased cancer-specific survival, compared to patients without detectable Grx2c. These results were supported by data from "The Cancer Genome Atlas". In synopsis, the results presented and discussed in these articles and manuscripts, support the concept of specific redox signalling in different models and model organisms. They also demonstrate the importance of the specific redox control of signalling pathways that, in the case of errors or misinterpretations, contribute to pathophysiological alterations. The regulation of the CRMP2 redox switch by Grx2c, for instance, is physiologically essential for brain development, but might lead to cancer progression, if "switched on" in adult tissue. Identification of further interaction partners as well as the development of compounds modulating this redox switch and CRMP2s conformations, will be part of our future research.
This thesis aims to develop a palaeogeographic and chronostratigraphic model of the southwestern Baltic Sea area, to improve our understanding of the depositional history of the Late Pleistocene on both a local and a transregional scale. New sedimentological, palaeontological and numerical age data will be presented from three reference sites located at the coast of NE Germany. So far, the chronostratigraphic assignment of Saalian and Weichselian sediments of NE Germany has been based mainly on lithostratigraphic methods and on sparse numerical age data, resulting in a fragmentary age database. Modern sedimentological approaches, such as facies analyses, have been applied only at a few isolated profiles. Thus, a reliable reconstruction of the depositional environments and their stratigraphic positions is still missing for the study area, which makes the correlation between Pleistocene successions from NE Germany and other circum-Baltic regions problematic. To address these lithostratigraphic and geochronologic issues, three crucial profiles were re-investigated using a multiproxy approach, including sedimentological, geochronological, and palaeontological techniques. The Glowe and Kluckow sites are located on the peninsula of Jasmund (Rügen Island), whereas the Klein Klütz Höved (KKH) section is situated between Wismar and Travemünde at the coast of the Mecklenburg Bay. The age-constraining of critical horizons was conducted by luminescence dating of feldspar and quartz grain minerals. Together, these successions represent the Late Saalian to Late Weichselian period and give rise to the following picture. The Glowe and Kluckow sections reveal that ice-free conditions dominated the study site between 47 and 42 ka. Deposition occurred in a steppe-like environment with moderate summers and cool winters. Meandering and braided river systems inhabited by various freshwater species, such as Anodonta cygnea, Pisidium amnicum and Perca fluviatilis, shaped the landscape. A subsequent cooling phase resulted in the establishment of a periglacial landscape and the formation of ice-wedges. This phase is shown in this thesis to be connected to the Klintholm advance documented at 34±4 ka in Denmark. Furthermore, the data indicate the formation of a lacustrine basin during the transition of MIS 3 to MIS 2 under sub-arctic climate conditions. A potential link to the Kattegat ice advance (29 – 26 ka) will be proposed. At 23±2 ka, the study area was characterised by proglacial and ice-contact lakes related to the Last Glacial Maximum ice advance of the Scandinavian Ice Sheet (SIS). This is the first documented SIS advance of Weichselian age, which reached Jasmund at 22±2 ka. The KKH sedimentary succession comprises deposits of Late Saalian to Late Weichselian age: after a period of deglaciation between ~139-134 ka (Termination II; MIS 6), which is preserved in a glaciofluvial sequence deposited in a braided river system, a lacustrine environment was established in an arctic to subarctic climate. During this time, the landscape was vegetated by typical Late Saalian flora communities. The Eemian interglacial is represented by lacustrine to brackish deposits covering the reference pollen zones 1 to 3. During this initial part of the Eemian, thermophile forest elements spread (Quercus, Ulmus), indicating a deciduous forest. The presence of brackish ostracods represents the influence of a marine transgression between 300 and 750 years after the beginning of the Eemian period. A hiatus of more than 90,000 years separates the Eemian from the overlying Late Weichselian sediments. During the Late Weichselian period, the deposition at KKH was dominated by glaciolacustrine and subglacial facies, where the first Weichselian ice advance occurred at 20±2 ka. The sedimentological and geochronological findings in this thesis provide valuable information for the reconstruction of the palaeoenvironmental history from the Late Saalian to Late Weichselian period. The Late Saalian palaeoenvironmental setting is reconstructed, including Termination II and the initial phase of the Eemian interglacial. Furthermore, the Eemian marine transgression is shown to have occurred 300 to 750 years after the beginning of this interglacial. The first proven Weichselian advance of the SIS approached NE Germany between ~23 and ~20 ka. In contrast, there is no evidence to support a pre-LGM advance of Weichselian age to the study area, as proposed by several authors, neither at Glowe and Kluckow, nor at the KKH site. Based on the presented results, and contra what was previously assumed, the MIS 3 Ristinge and Klintholm advance of the SIS, documented in Denmark, did not reach NE Germany.
Tourism is a multifaceted economy and based on existing nature, as well as on culture in a geographical space to become a successful destination for tourism. The topic of this survey is how tourism in the transitioning country of Vietnam influences culture and nature or vice versa. A special focus will be on the transitioning aspect. This study gives insights about how in the transitioning country of Vietnam, tourism can act as an additional driver of change in terms of nature and culture or if tourism is only adapting to these changes. Therefore in the beginning the subject of ‘social-ecological transformation’ is described and furthermore the situation in Vietnam will be introduced. The key aspects here will be within the range of geography and sociology. It becomes evident, that scientific views on this topic are rather diverse, but nevertheless many theoretical aspects can be observed also in the investigation area Vietnam. Within the country several aspects of economic transition already became reality, while others, like social, ecological or political reforms, are still at the beginning. The empirical part of this study deals with existing thoughts, according to the topic of transition, in relation to tourism development and respectively to environmental understanding, by analyzing and comparing positions of 21 international and Vietnamese experts, 569 international tourists and 710 Vietnamese students. By doing so, similarities within opinions about tourism development and the environmental situation in the country became observable. While tourism is rated as a mostly positive development, the current environmental situation has mostly been criticized by all survey participants. Apart from that, connections between both aspects (tourism economy and nature) are often of no importance or the relationship is identified to be just a rudimentary one. In case of these opinions, involvement within one social group and personal experience is of larger importance than cultural conditioning (European or Asian), e.g. own travels, own jobs and own education. This fact becomes visible by very similar ratings of environmental problems on the one hand and the beauty of natural landscapes on the other hand, done by both survey groups; namely international tourists and Vietnamese students.
Encephalitides induced by lyssa-, borna- and astroviruses: molecular detection and characterization
(2017)
Encephalitis is a severe inflammatory disease of the brain which often has a fatal outcome or can lead to subsequent damages. In around two-thirds of all human encephalitis cases, the causative agent is, despite improved diagnostics, unknown today. Aim of this work was the development, improvement and validation of diagnostic methods, improvement of sampling strategies and the development of optimized systems for characterization of three viruses causing viral encephalitis. The main burden of RABV lies in developing countries, were standard diagnostic tools are often not realizable. Therefore, simple and rapid diagnostic tests for the use under resource limited settings, so called point-of-care tests (POCT), are favorable. Commercially available lateral flow device (LFD) based immunodiagnostic tests were analyzed and failed in terms of sensitivity compared to the standard FAT and RT-qPCR (Paper I). Therefore, molecular RABV alternative targeting genome tests were developed and combined with rapid nucleic acid extraction methods. The new HighSpeed RT-qPCR and RPA assays together with magnetic bead based automated or manual extraction methods delivered a specificity between 100% and 97.2% and a limit of detection of 10 or 1,000 genome copies per reaction, respectively and seem suitable as novel POCT (Paper II). Recently, a novel zoonotic VSBV-1, responsible for fatal encephalitis of three squirrel breeders, was detected. For further investigations of this new virus, methods for an in-vivo sampling approach of squirrels were established. They were useful to identify animals harboring this dangerous virus, and new sequence data could be obtained from the VSBV-1 positive animals. Until now, 3.5% of all investigated squirrels were VSBV-1 RNA positive and two subfamilies (Sciurinae and Callosciurinae) are affected. The pathogen occurs not only in Germany, but also squirrel holdings and zoological gardens in the Netherlands and Croatia were tested positive, indicating a serious human health threat of this virus (Paper III and IV). With the help of a metagenomic approach, astroviruses were detected to be associated to encephalitis in cattle and sheep. These viruses were detected in a cow in Germany (Paper V), and in brain samples from two sheep in the United Kingdom (Paper VI). In both cases, the sequences generated by high-throughput-sequencing (HTS) were confirmed by specific RT-qPCRs, which could be used for subsequent screening approaches. Together, methods for the detection of three different encephalitis viruses were developed, validated and applied for different sample material.
Presumably every organism on earth is involved in at least one mutualistic interaction with one or several other species. To interact with each other, the species need traits that provide benefits to the partner species. Surprisingly, the function of traits for the stabilization of mutualisms has rarely been investigated, despite of a general lack of knowledge how mutualisms are maintained. The aim of this work was to find functional traits, which stabilize the mutualism between a bat species and a carnivorous pitcher plant in Northern Borneo. Kerivoula hardwickii is the only bat species known to roost in pitcher-shaped trapping organs of Palaeotropical pitcher plants (Nepenthes). These bats fertilize the pitcher plant Nepenthes hemsleyana with their nutritious nitrogen-rich faeces while roosting inside the pitchers. The plants have outsourced capture and digestion of arthropod prey to the bats on which they strongly rely for nutrient acquisition. The bats in contrast are less dependent on their mutualism partner as they also roost in pitchers of two further Nepenthes species as well as in developing furled leaves of various plant species in the order Zingiberales. In earlier studies, we found that N. hemsleyana outcompetes alternative roosts by providing high-quality roosts for the bats. However, which traits exactly stabilize the mutualism between K. hardwickii and N. hemsleyana was still unclear. I found that both the bats and the pitcher plants show traits, which have the potential to stabilize their interaction. On the level of morphological traits, I found that the pitchers have a low fluid level and a particular shape that provide just enough roosting space for one individual of the solitary K. hardwickii, a mother with juvenile or a mating couple. The bats have enlarged thumb and foot pads that enable them to cling to the smooth surfaces of their roosts without using their claws. This avoids damage to the sensitive N. hemsleyana pitchers. On the level of communicational traits, again N. hemsleyana acquired morphological structures that act as effective ultrasound-reflectors, which guide the echo-orientating bats to the opening of the pitchers and help the bats to identify their mutualism partner. The bats’ calls on the other hand are characterized by extraordinary high starting frequencies and broad bandwidths, which enable K. hardwickii to easily locate pitchers of N. hemsleyana and other Nepenthes species in their dense habitats. Finally, on the level of behavioural traits the bats often but not always prefer their mutualism partner to other roosts when they can select roosts in their natural environment or in behavioural experiments. The reason for this behaviour seems to be a combination of 1) N. hemsleyana’s superior quality compared to alternative roosts and 2) different roosting traditions of the bats. In conclusion, the mutualism between bats and pitcher plants is asymmetric as N. hemsleyana is more dependent on K. hardwickii than vice versa. For the plants bat faeces present their most important nutrient source. In contrast, K. hardwickii can select between alternative roosting plants. This asymmetric dependency is reflected in the specifity and function of the traits that stabilize the mutualism in each of the two involved species. Especially on the morphological level, N. hemsleyana seems to have evolved several traits that perfectly fit to K. hardwickii. In contrast, the bats’ traits more generally facilitate their roosting in funnel-shaped plant structures and their occurrence in cluttered habitats. Thus, they are probably exaptations (i.e. traits that evolved for another reason) that are nevertheless functional and stabilize the mutualism with N. hemsleyana. This plant‘s superior roost quality is likely a consequence of the competition with alternative roosting plants and is a pre-requisite for the bats to prefer N. hemsleyana. Moreover, my study confirms earlier findings that asymmetric dependencies support the stabilization of mutualistic interactions. Finally, my work indicates that the specifity of functional traits can be used as a measure to determine mutual dependencies of mutualistic partners.
Deflected by the barrier function of topographical structures such as high mountain ranges, open water bodies or desert, migrating birds concentrate at certain points or corridors referred to as ‘bottlenecks’. An area like this was discovered at Mount Besh Barmag (Azerbaijan) in autumn 2007, but the data gathered during a four-week survey was insufficient to do more than hint at the existence of a major bird migration bottleneck. Therefore, a comprehensive bird migration study was conducted to analyse the magnitude of this potential bottleneck site. The study covers the periods from August to mid-November 2011 and from March to the end of May 2012 and includes daily counts at three observation points focusing on three different migrant types: passerine, waterbirds and soaring birds. In addition, a sound recorder with an omnidirectional microphone collected bird migration calls by both day and night. In total, 278 bird species were observed in an estimated passage of 1,239,369–1,514,267 diurnally migrating individuals in autumn 2011 and 646,733–817,183 individuals in spring 2012. Fifteen species passed through the study area in numbers exceeding 1% of their world populations and 34 species in more than 1% of their flyway populations in at least one of the observation periods. 84% of the observed migrating birds in autumn 2011 and 95% of them in spring 2012 passed through at heights below 50 m above ground exposing them imminently to the danger of collision with obstacles. In the analysis of nocturnal sound recordings, 119 bird species were identified of which 106 were expected to occur as migrants, and calculated estimates revealed the occurrence of 108,986 calls in autumn 2011 and 33,348 calls in spring 2012. The volume of diurnal bird migration emerging from the data with respect to species number and number of individuals is certainly a strong indication of the existence of a major bird migration bottleneck at Besh Barmag. On account of methodological constraints, the high number of night flight calls can only hint at a nocturnal bird migration bottleneck and confirmatory research aided by visual methods (radar, thermal imaging) is necessary to back up the acoustic results. The Besh Barmag bottleneck offers a great opportunity to establish a standardised long-term monitoring programme to investigate avian population dynamics in the vast and little known Eurasian landmass. Acoustic-based monitoring might be a cost-effective method, but it is limited to a few vocally prolific species only. The aim should rather be the establishment of a bird observatory as already successfully installed in a number of European bird migration bottlenecks.
Leaf-inhabiting fungi are a hyperdiverse group of microbiota found in all terrestrial habitats. Comparative studies targeting the drivers of endophytic fungal biodiversity are rare and identified multiple effectors, such as plant chemistry, climate and seasonal attributes. Our project aimed to study the pattern of the leaf-associated mycobiome of European beech (Fagus sylvatica) at altitudinally distinct sites to reveal diversity, composition and seasonal dynamics of fungal endophytes by a combination of metabarcoding, cultivation and subsequent ecological analyses. This thesis also intended to study the fungal relationship with biotic and abiotic factors: elevation, local site conditions, leaf biochemistry and leaf status. Metabarcoding and cultivation were applied for same leaf samples to trace both environmental drivers and method-dependent signals of the detected fungi. An experimental field site consisting of 100 (2-years old beech) trees was established called ‘beech phytometer’ system at two altitudes (517 and 975 m a.s.l.) in a German mountain forest. Beech trees were randomly selected from both sites as well as from neighboring beech trees. Ten trees from each site were chosen and 10 leaves per tree were sampled. Climatic and leaf biochemistry (Chlorophyll, flavonoid and nitrogen) data were seasonally (Autumn, Spring and Summer) investigated for two continuous years (Oct 2013 to Oct 2015) at these two elevations. In the first year (autumn, 2013) of the project (chapter 3.1), the leaf-inhabiting fungi of natural beech trees were investigated by using high-throughput sequencing (metabarcoding) at three altitudinally distinct sites (with timberline at 1381 m a.s.l.) in the German Alps. This paper focuses on a detailed description and evaluation of metabarcoding amplicon library preparation and a subsequent analytical workflow. Fungal diversity and community composition were compared as a function of different elevated sites and leaf status (i.e., vital or senescent). However, three investigation sites resulted in 969 OTUs (operational taxonomic units) from 820441 sequences. Taxonomic compositions (order) of beech fungi differed strongly among the three sites but were less distinct between the vital and the senescence leaves. Fungal community composition at valley site clearly differed from those of mountain and timberline where differences between mountain and timberline were less prominent. Vital and senescence leaf differed in fungal community structures indicating a strong dynamics of leaf fungi in autumn. Elevation and leaf status were found to be the main explaining factors, which affected the fungal richness and compositions. Another survey (Chapter 3.2) was conducted just after the establishment of the ‘beech phytometer’ trees in the same period (autumn 2013) where leaf mycobiome of the phytometer trees (trees originally came from Northern Germany and grown in nursery) were compared with the fungi of surrounding natural beech habitat at valley (517 m a.s.l.) and mountain site (975 m a.s.l.) in the same location “Untersberg”. Fungal diversity was lowest in the managed habitat in the nursery and was highest in natural habitat. Fungal diversity and compositions significantly associated the origin of the trees. Under natural conditions, the fungi were more diverse at lower altitudes than at higher altitudes. Additionally, leaf chlorophyll and flavonoid contents showed negative correlations with fungal richness in natural stands. In the second year (autumn 2014), another survey (chapter 3.3) was conducted on leaf endophytes of phytometer trees with metabarcoding and cultivation approaches to trace the environmental drivers and method-dependent indications. Metabarcoding resulted in 597 OTUs from 170480 curated ITS1 reads and cultivation revealed 70 OTUs from 438 culture-based Sanger sequences. Both approaches resulted in non-overlapping community compositions and pronounced differences in taxonomic classification and trophic stages. However, both methods revealed similar correlations of the fungal communities with local environmental conditions. Our results indicate undisputable advantages of metabarcoding over cultivation in terms of representation of the major functional guilds, rare taxa and diversity signals of leaf-inhabiting fungi. This stressed out the importance of cultivation for complementing sequence databases with good quality reference data and encouraged the use of both approaches in future microbial biodiversity assessment studies. Phytometer and natural trees were intensively investigated in this study (chapter 3.4) to assess the influence of site characteristics (altitudes, local microclimate), seasonality, leaf biochemistry and leaf age on fungal diversity and composition. In total, our analytical Illumina workflow resulted in 15703599 demultiplexed and ITS1 reads from 165 samples. Clustering at 97% similarity resulted in 1199 OTUs. Climatic parameters were significantly differed between valley and mountain on daily basis but were insignificantly differed on monthly basis. The compositional difference between phytometer and natural mycobiome was significant for combined data as well as for the seasonal data (Oct 2013-Oct 2014). We observed a strong seasonal turnover in phyllosphere fungi in both habitats over the two years of investigation, suggesting that the plant-fungal system not only responds to cyclic climatic conditions but depends as well on various parameters, e.g., geographic position, substrates age and surrounding vegetation. A side (chapter 3.5) study was done to see the connection between the foliar endophytes and foliar phenolic compounds of European aspen (Populus tremula) in the presence and absence of specialist beetles (Chrysomela tremula). A distinct pattern of the leaf endophytes was found to be associated with aspen genotype and chemotype, but this specificity disappeared in the presence of herbivorous beetles. This suggested that leaf endophytes responded to the herbivory in aspen. In general, the altitudinal difference is the most important explaining factor for fungal community differences, which shapes many dependent abiotic and biotic habitat factors. Regarding cost and time per sequence, metabarcoding is superior to cultivation approaches and offers surprisingly profound insights by yielding much more data, allowing to test at once multiple hypotheses in fungal ecology.
The content of this thesis can be summarized as follows: (i) The deposition processes of SiOx and SiOxCyHz coatings were investigated in a low-pressure, low temperature HMDSO-O2-N2 plasmas. Infrared laser absorption spectroscopy (IRLAS) and optical emission spectroscopy (OES) were combined to measure the gas temperatures in the hot and colder zones of the plasma as well as to monitor the concentration of the methyl radical, CH3, and of seven stable molecules, HMDSO, CH4, C2H2, C2H4, C2H6, CO and CO2. Tunable lead salt diode lasers (TDLs) and an external-cavity quantum cascade laser (EC-QCL) were simultaneously employed as radiation sources to perform the IRLAS measurements. They were found to be in the range between 10^{11} to 10^{15} cm^{−3}. The influence of the discharge parameters of power, pressure and gas mixture on the molecular concentrations was studied. The plasma generation is characterized by a certain degree of inhomogeneity with different temperature zones, i.e., hottest, hot and colder zones depending on the construction of the reactor. This complexity is characterized by the multiple molecular species including the HMDSO precursor and products in ground and excited states existing in the plasma. (ii) Employing similarly IRLAS and OES techniques, the deposition of nanocrystalline diamond at relatively low temperature in low-pressure MW H2 plasmas with small ad-mixtures of methane and carbon dioxide was investigated. Five methods were applied for an extensive temperature analysis, providing new insights into energetic aspects of the multi-component non-equilibrium plasma. The OES method provided information about the gas temperature of H2 inside the MW plasma. Using lead salt diode lasers, the rotational temperature of the methyl radical, CH3 , and gas temperature of methane molecule, CH4 , was measured. A variety of CO lines in the ground and in three excited states have been analysed using an EC-QCL with a relatively wide spectral range. These methods have shown that based on the construction of the DAA reactor using 16 single plasma sources the plasma generation is characterized by a variety of hottest, hot and colder zones. Extensive measurement of these various species temperatures in the complex plasma enabled the concentration determination of the various stable and unstable plasma species, which were found to be in the range between 10 11 to 10 15 cm −3 . The influence of the discharge parameters, power and pressure, on the molecular concentrations has been studied. To achieve insight into general plasma chemical aspects, the dissociation of the carbon precursor gases including their fragmentation and conversion to the reaction products was analysed in detail. The evolution of the concentration of the methyl radical, CH 3 , of five stable molecules, CH4, CO2, CO, C2H2 and C2H4, and of vibrationally excited CO in the first and second hot band was monitored in the plasma processes by in situ infrared laser absorption spectroscopy using lead salt diode lasers (TDL) and an external-cavity quantum cascade laser (EC-QCL) as radiation sources. OES was applied simultaneously to obtain complementary information about the degree of dissociation of the H2 precursor gas. The analysis of the carbon and oxygen mass balances shows clearly, that the deposition on the reactor walls and the production of other hydrocarbons species may act as sinks for carbon and oxygen. (iii) The absolute line strengths of many P-branch transitions of the ν3 fundamental of {28}^SiH4 were determined using the wide tuning range and the narrow line width of a cw EC-QCL between 2096 and 2178 cm^{−1}. The line positions and line strengths of transitions of the stretching dyad within the P-branch of {28}^SiH4 were determined with an estimated experimental measurement accuracy of 10%. The high spectral resolution available has enabled us to resolve and measure representative examples of the tetrahedral splittings associated with each component of the P-branch. The positions of these components are in excellent agreement with spherical top data system (STDS) predictions and theoretical transitions from the TDS spectroscopic database for spherical top molecules. To our knowledge, this is the first reported measurement of these line strengths in this band and is an example of the applicability of high-powered, widely tunable EC-QCLs to high resolution spectroscopy in the MIR. (iv) Similarly, the determination of the silyl radicals, ν3 band, line strengths is ongoing using the same cw EC-QCL. This effort was impaired by silane and other unknown species lines overlap; however, the silyl radicals was successfully detected in a SiH4/H2 plasma. A method to determine the silyl line strengths has been presented through its iterative decay measurements which relied on the value of the silyl radical self reaction constant. There was a consensus of its value in the literature.
The virosphere comprises all known and unknown viruses in our ecosystems. Advanced sequencing technologies in combination with metagenomic analysis have become a key tool for exploring this global diversity of viruses. However, discovery of novel viruses and comparative analyses are often based on small sequence fragments or lack biological context, which restricts a proper classification. In this study advanced genomic methods were used that included comprehensive knowledge of viral genomes along with supporting biological metadata in order to identify and classify viruses at different levels of genetic relationships. In a first example, the genetic background of vaccine-induced rabies cases was revealed by analyzing and comparing the genetic diversity of viral populations. Furthermore, the fundament for a taxonomic reclassification of orthopoxviruses was established on basis of a wide scale genomic analysis. In addition, novel neurotropic mamastroviruses from sheep and cattle were classified as members of a single species that provided evidence of interspecies transmission. Finally, two putative novel species of alphaherpesviruses and orthopoxviruses were identified. These examples are based on field cases that provide substantial corresponding clinical metadata and information of host-pathogen interactions. The analyses, therefore, puts taxonomic classification into biological and epidemiological context, rather than addressing generic phylogenetic relationships. Furthermore, the presented work demonstrates that a universal approach for virus classification is neither feasible nor reasonable as analyses must be adjusted the nature of the addressed virus. All results with impact on the current taxonomic classification will be or are already reported to the International Committee on Taxonomy of Viruses. In conclusion, this thesis contributed to the classification concepts of viruses and expanded the knowledge of virosphere diversity.
Background: Early childhood caries remains an unsolved problem in children under three worldwide. Midwives are important health care persons around birth and can shape behavior. They possibly can play a positive role in preventing early childhood caries in young children. Objective: to assess how involved midwives are in early childhood caries prevention, what preventive measures they recommend and what knowledge they have about early childhood caries, as well as to study the potential differences between the various federal states or due to their work experience. Materials and Methods: An online survey targeted midwives in Germany regarding their knowledge about early childhood caries as well as the preventive measures they recommended. Participants were members of the German Association of Midwives (DHV). The survey invitation was published with the monthly newsletter and in the association journal of the DHV. Data was collected anonymously. Results: 191 midwives nationwide responded to the questionnaire. Most midwives were aware about ECC prevalence, consequences, causes and the teeth mainly affected. Midwives gave excellent recommendations regarding diet, oral hygiene and avoiding prolonged bottle feeding. However, only 40.8% of midwives recommended the first dental visit with the eruption of the first tooth. 71.7% recommended a fluoride tooth paste with the eruption of the first tooth. The rest advised a later use or non-fluoridated toothpaste. Regional differences were minimal. Conclusion: Midwives have good oral health knowledge, but there is some variability in recommendations on the first dental visit and the use of fluoride toothpaste which reflects an inconsistency of professional recommendations delivered by different health care institutions in Germany.
Introduction: Ketamine (KET) is widely used as anaesthetic drug. Beside its pronounced an-aesthetic effects as caused by antagonism of NMDA receptors, ketamine also causes potent analgesia. Moreover, There are ample new evidences, firstly, that 2R,6R/2S,6S-enantiomers of hydroxynorketamine (HNK), exert neuro-modulating effects by AMPA-receptor activation and, secondly, that the plasma levels of norketamine (n-KET) after oral dosing are higher than after intravenous administration. From the physicochemical point of view ketamine is expected to be a substrate of drug transporters. Thus, it was the aim of this study to separate and quantify KET and its metabolites in human serum, urine and feces; investigate the role of transporter proteins in the intestinal absorption, distribution and elimination of ketamine; and evaluate pharmacokinetics and metabolism of a newly developed prolonged-release keta-mine dosage form to confirm its suitability for chronic treatment of CNS-diseases (e.g. de-pression) according to the new “ketamine metabolite paradigm”. Materials and methods: Quantification of ketamine was done by a LC-MS/MS-based quantifi-cation method on the QTRAP4000 instrument. Samples were extracted by methyl tert-butyl ether after addition of sodium carbonate to liberate the free base; Single transfected MDCKII cells overexpressing OCT1, OCT2, OCT3, and MATE1 or MATE2K, and HEK293 cells over-expressing OATP2B1 were used to study the cellular uptake of ketamine. Inside-out lipovesi-cles were used to determine the affinity of ketamine to the efflux transporter P-glycoprotein (P-gp). Uptake into cells or vesicles was determined by liquid scintillation counting. Func-tionality of all in vitro systems was assured by using in each case appropriate probe sub-strates; The dose-escalation study was performed in five consecutive periods (7 days wash-out) in 15 healthy subjects (5 females and 10 males. 20-35 years, BMI 19.4-27.6 kg/m2). Results: We introduce for the first time the separation and quantification of the active me-tabolites 2R,6R/2S,6S-HNK; Ketamine was shown to be taken up significantly in a time- and concentration-dependent manner by OCT1-3. The affinity to OCT transporters at pH=6.5 was several fold higher than that at pH=7.4. ), ketamine showed a significant but low affinity to P-gp. In contrast to this, we could not detect any transport of ketamine by MATE1 / 2K or OACPT2B1; and PR-KET was safe and well tolerated with higher metabolites productivity, different pharmacokinetic properties and longer T1/2 when compared to IV-KET or IR-KET. Conclusion: the uptake transporters OCT1 & 3 and the efflux transporter P-gp may play a role in the intestinal absorption of the drug. On the other side, P-gp, MATE1 / 2K and OCT are not expected to contribute significantly to tissue (brain) distribution or renal excretion of ketamine; Moreover, the prolonged-release ketamine undergoes dose-dependent “first-pass” metabolism which generates substantially increased plasma exposure of downstream me-tabolites with potential neuro-modulating effects compared to ketamine after intravenous administration.
The aim of the study was to develop and evaluate the reliability and agreement of new computer planimetric method for measurement and assessment of plaque on all types of removable dental prostheses RPDs. The instrument (new method) was tested by evaluating the efficacy of the rotating needles device in cleaning specific parts of RPD. From a database containing 780 images, which were taken in a standardized method for 65 RDPs for 49 participants, 55 images were selected randomly for image analysis. Adobe Photoshop software was used according to a standard operating procedure (SOP) by a main examiner two times in different sessions, and 1 time by 3 other examiners. In order to estimate the intra- and inter-examiner reliability, intraclass correlation coefficients ICC(2,1) was used. Three parameters were used to estimate agreement: standard error of measurement (SEM), smallest detectable change at 95% confidence level (SDC95%), and limits of agreement (LoA) according to Bland¨CAltman method. In the database, only 34 subjects were found with double crown retained removable denture and veneer over the secondary crown. 49x2 (before x after) images for 34 RDPs went under image analyses to calculate POP before and after cleaning the RDPs with the rotating needle device. Data were analysed using Wilcoxon signed-rank test. In all steps of image analysis, both intra-examiner and inter- examiner reliability were excellent with ICC(2,1) values > 0.85 at 95% confidence level. Intra- and inter-examiner values for both, SEM and SDC95% were ¡Ü 6% and ¡Ü17% respectively. The Bland¨CAltman analysis revealed a satisfactory level of agreement. POP is significantly more on the veneer than on the base(B-O), P <0.05. The rotating needles device is effective in cleaning the veneer and base(B-O), P <0.05 with absolute effect size 0.62. No statistical significance was detected in the effectiveness of the rotating needles device between base(B-O) and veneer. This study showed an excellent inter- and intra-examiner reproducibility, satisfactory level of examiners agreement, and acceptable measurement error of the new computer planimetric method . Furthermore, the method can be used with all types of RDPs. The rotating needles device can significantly reduce plaque on the double crown retained removable denture. The Computerized Planimetric Method (CPM) is more suitable for clinical researches because of its objectivity, reliability, high level of standardization, and the ability to detect and quantify small changes in plaque. Extra attention should be given to the veneer over the secondary crown as they are a potential part for RDP plaque accumulation.
The present doctoral dissertation comprises new studies on the fossil vertebrate assemblage recovered from the late Early Jurassic marine “Green Series” clay deposits of Grimmen and Dobbertin in north-eastern Germany that contribute to fill the gap of knowledge regarding its faunal composition and its relevance for understanding Early Jurassic vertebrate life. The investigations led to the recognition of wide range of vertebrate taxa, including basal gravisaurian sauropods, secondarily marine reptiles, a diverse fauna of leptolepid fishes, and a new genus and species of pycnodontiform fishes. In addition, a taxonomic revision of the Early Jurassic saurichthyid fish Saurorhynchus was performed, leading to the identification of two new, previously unnamed species. The results provide new insights into the taxonomic, systematic, and ecological diversity of Early Jurassic vertebrates, and hence add significant new data to our knowledge on Lower Jurassic vertebrate palaeobiodiversity patterns.
The thesis is about ideological change of political parties and the way parties gather information, learn by updating their beliefs and ultimately make "rational choices". Analyzing 1451 policy moves of 137 parties in 22 OECD-countries from 1950 to 2013 it is a story about rational learning, about emulating other parties abroad and chasing public opinion. Yet, the "internal life" of a party conditions the effects when activists have some influence over the formation of party policy. As volunteers facing a scarcity of time and resources, members of the party on the ground have a different information horizon, and may arrive at the opposite decision where to move than party elites which (can) rest their decision on a broader set of information resources. In some parties the party on the ground thus constitutes an "internal wall of resistance" to the strategy party elites would choose, if they were free from constraints.
The establishment and management of protected areas has become a universally accepted way to conserve biodiversity and the wide range of goods and services they offer. Sustainable management of forest resources requires good decision-making from a range of different stakeholders. This dissertation develops a model based on spatial data and expert judgments to assess the vulnerability of the most threatened species of fauna and flora in a selected protected area. Based on the study objectives, the availability of data and technology, the study concludes vulnerability as composed of multidimensional losses, which can be measured as a function of the three components: exposure, sensitivity and adaptive capacity. In order to measure vulnerability, the research applies the Analytic Hierarchy Process (AHP), a well-known multi-criteria decision making approach, using the open access Super Decisions software in a spatial database context with the help of Geographic Information Systems (GIS).
The thyroid gland is of crucial importance in human metabolism. Its main secretion products, L-thyroxine (T4) and 3,3’,5-triiodo-L-thyronine (T3), are essential for proper development of multiple tissues and organs as well as for their functioning in the adult organism. The secretion of thyroid hormones (TH) is stimulated by thyrotropin (TSH) released from the pituitary gland. This tight connection between both hormones is of crucial importance for the clinical diagnosis of thyroid dysfunction. During the last two decades the concept of TH action developed to increased complexity. However, most of the recent advances in the field of TH research are based either on cell culture, tissue or animal models or stem from studies investigating specific hypotheses in humans. Thus, experimental approaches for the comprehensive, hypothesis-free characterization of metabolic effects of classical and non-classical TH in human are urgently needed. This holds true in particular for the TH derivative 3,5-diiodothyronine (3,5-T2). It was described to alleviate the typical detrimental metabolic consequences of a high-fat diet and even reversed hepatic steatosis. To replicate these experimental findings from rodents in humans, comprehensive data from the population-based Study of Health in Pomerania (SHIP) was analyzed in the present work. Based on a euthyroid, diabetes-free SHIP-subsample (N=761), non-linear associations between the serum concentrations of 3,5-T2 and glucose as well as TSH were detected. In contrast, no significant 3,5-T2 associations with several anthropometric markers or blood lipid parameters were observed, partially questioning the transferability of the beneficial metabolic 3,5-T2 effects reported for pharmacological intervention studies on rodents to humans. Recent advances in technological development now allow for the use of high-throughput spectrometric platforms to characterize the small molecule content (metabolome) of blood and urine samples. The detected metabolome constituents can be associated with any relevant parameters of interest, thereby extending the scope of classical association studies. Therefore, in the second part of the present thesis, the metabolic fingerprints of FT4, TSH as well as the ratio log(TSH)/FT4 as markers of thyroid function were profiled. Strong differences between the metabolic fingerprints of FT4 and TSH were observed, partially alleviated by the log(TSH)/FT4 ratio. These findings not only emphasize the high diagnostic value of the combined evaluation of TSH and FT4 in the assessment of thyroid function but additionally argue for a holistic approach in the diagnosis of thyroid function. More moderate endogenous effects of 3,5-T2 were evaluated by comparing its urinary metabolic fingerprint with that of the classical TH. A number of associations became apparent, indicating a function of endogenous 3,5-T2 in intermediary metabolism. Besides partially confirming associations with respect to the presented findings in animal studies, the strongest 3,5-T2-association was observed with trigonelline, a metabolite described earlier to exhibit similar beneficial effects as 3,5-T2 on glucose metabolism when used as a pharmacological agent in animal studies. An association towards hippurate indicated a partial overlap with the metabolic profile of TSH and hence consolidated results from the first two projects in the sense of a thyromimetic role of 3,5-T2 in the feedback regulation of TH. The diagnosis of thyroid disorders based on the classical markers TSH and FT4 suffers from restricted sensitivity in the subclinical range as both parameters have broad reference ranges in the general population. Therefore, in an approach to detect novel peripheral biomarkers of thyroid function, sixteen healthy young men were challenged with 250 µg of levothyroxine (L-T4) over a period of eight weeks in the fourth project presented here as part of this thesis. Monitoring of the volunteers over a period of sixteen weeks allowed delineation of the metabolic shifts first towards thyrotoxicosis and later in the context of the restoration of euthyroidism. The use of mass spectrometry for the comprehensive characterization of the metabolite as well as the protein content of samples taken at the different time points revealed profound molecular alterations, despite the lack of any clinical symptoms in the volunteers. Molecular signatures of thyrotoxicosis indicated increased energy expenditure, pronounced defense against systemic oxidative stress, a general drop in apolipoproteins, as well as increased abundances of proteins related to the coagulation cascade and the complement system. Good and robust classification of the thyroid state independent of TSH and FT4 was achieved using random forest analysis with a subset of fifteen metabolites and proteins, indicating new options in the individualized diagnosis of thyroid disorders.
Humanity is plagued by many diseases. Beside environmental influences, many --- if not all --- diseases are also subject to genetic predisposition and then display molecular alterations such as proteomic or metabolic aberrations. The elucidation of the molecular principles underlying human diseases is one of the prime goals of biomedical research. To this end, there has been an advent of large-scale omics profiling studies. While the field of molecular biology has experienced tremendous development, data analysis remains a bottleneck. In the context of this thesis, we developed a number of analysis strategies for different types of omics data resulting from different experimental settings. These include approaches for associations studies for plasma miRNAs and time-resolved plasma omics data. Furthermore, we devised analyses of different RNA-Seq transcriptome profiling studies coping with problems such as lack of replicates or multifactorial experimental design. We also designed machine learning frameworks for the identification of discriminatory biomolecular signatures analysing case-control or time-to-event data. All of the strategies mentioned above were developed and applied in the contexts of multi-disciplinary endeavours. They aided in the identification of plasma miRNAs associated with age, sex, and BMI as well as plasma miRNAs bearing potential as diagnostic biomarkers for non-alcoholic fatty liver disease (NAFLD). This thesis significantly contributed to a study demonstrating the utility of plasma miRNAs as prognostic biomarkers for major cardiovascular events such as ST-elevation myocardial infarction. Our approaches for analysing RNA-Seq data aided in the characterisation of murine models for Alzheimers disease and the transcriptional response of human gingiva fibroblasts to ionizing radiation exposure. Furthermore, the developed approaches were applied for studying a human model for thyrotoxicosis and for the successful identification of a multi-omics plasma biomarker signature of thyroid status. We are only beginning to understand the molecular principles underlying human diseases. The approaches and results presented in this thesis will contribute to improved understanding of biomolecular processes involved in common diseases such as Alzheimers disease, NAFLD, and cardiovascular diseases.
Transfusion-related acute lung injury (TRALI) is an adverse transfusion reaction and the major cause of transfusion-related mortality. The syndrome occurs within six hours after transfusion and is characterized by acute respiratory distress and the occurrence of a non-cardiogenic, bilateral lung edema. TRALI is almost entirely induced by leukocyte-reactive substances which are present in the blood product and get transferred to the recipient during transfusion. The majority of cases (~80%) is caused by leukocyte-reactive immunoglobulins and is accordingly classified as immune-mediated TRALI. The responsible antibodies are generated via alloimmunization and are directed against human leukocyte antigens of class I and II or human neutrophil alloantigens (HNA). Within the HNA class, HNA-3a antibodies have an exceptional clinical relevance as they are most frequently involved in severe and fatal TRALI cases. The high mortality was associated with their characteristic ability to induce a strong neutrophil aggregation response. The described clinical relevance of HNA-3a antibody-mediated TRALI motivates the screening for new strategies for preventive or acute pharmacologic intervention. Knowledge of the molecular pathomechanisms is a crucial prerequisite and thus, respective investigations are required. In order to achieve this goal, HNA-3a antibody-induced cytotoxicity and aggregation were assessed on the molecular level by usage of flow cytometry, the granulocyte agglutination test and by phosphoproteome analysis. The current study provides insight into molecular processes during HNA-3a antibody-induced neutrophil responses and is the first to assess neutrophils using global, gel-free phosphoproteome analyses. Accordingly, it is the first to provide neutrophil phosphoproteome data in the context of TRALI. Gel-free phosphoproteome analyses of primary neutrophils required the highly selective and sensitive phosphopeptide enrichment from stable and sufficiently large protein extracts. However, an appropriate workflow did not exist and was hence developed by sequential protocol optimization steps. The developed workflow was finally proven suitable for comparative gel-free phosphoproteomics when detecting the formyl-methionyl-leucyl-phenylalanine-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) signaling in a proof-of-principle experiment. The following single parameter analyses were conducted to investigate neutrophils for their responses to HNA-3a antibodies in absence and presence of proinflammatory priming conditions. Results revealed that the direct stimulation of neutrophils with HNA-3a antibodies will likely not cause the induction of cytotoxic effector functions. In contrast, neutrophils react predominantly by aggregation, a process which is potentially mediated by integrins and causes a secondary, subthreshold activation of solely ERK2. Accordingly, only the neutrophil aggregation response could also be enhanced by an appropriate priming. Taken together, the single parameter analyses proved neutrophil aggregation as the main pathomechanism in HNA-3a antibody-mediated TRALI and thus, the underlying signaling pathways were investigated by global, gel-free phosphoproteomics. The following phosphoproteome analyses indicated the induction of a biphasic signaling during 30 minutes of HNA-3a antibody treatment and signaling pathways of Rho family GTPases could be associated with the first and the second phase. Additionally, the involvement of ERK signaling was indicated in the second phase and this result corroborated thus the data of the previous single parameter analyses. The comprehensive analysis of the identified signaling pathways revealed Rho, Rac and Cdc42 as central regulators and the specific inhibition of Rho in the following validating experiments led very intriguingly to a significant enhancement of HNA-3a antibody-mediated neutrophil aggregation. Hence, this result indicated a potential inhibitory effect of HNA-3a antibodies on Rho activity. Therefore, Rho inhibition was suggested to occur in parallel to an adhesion-inducing signaling pathway and might hence be involved in the stabilization of neutrophil aggregates in HNA-3a antibody-induced TRALI. The results from this doctoral thesis contributed to the generation of a new pathogenesis model for HNA-3a antibody-mediated TRALI. In this model, neutrophils respond to direct HNA-3a antibody exposure predominantly by homotypic aggregation. These potentially very stable and primed aggregates accumulate in the lung and are susceptible to parallel, proinflammatory stimulation. Subsequently, this cascade leads to full neutrophil activation and finally to TRALI induction.
The four stranded G-quadruplexes are important secondary structures of nucleic acids formed by guanosine-rich sequences. Besides the application as scaffold for technological applications, they are involved in many cellular processes such as gene regulation, replication, or maintenance of chromosomal ends. Characteristically, a large diversity of quadruplex structures is observed, whereas the correlation between sequence and structure is still not fully understood. In this thesis, the effects of modified nucleotides on G-quadruplexes were analyzed using NMR-spectroscopy to gain insight into driving forces determining the folding process. Contrary to DNA quadruplexes, the folding landscape of RNA structures is mostly restricted to parallel topologies. Therefore, ribose moieties were introduced into DNA sequences to isolate the effect of the additional hydroxy group. In this way, sequential CHO hydrogen bonds between the 2′-OH and the H8 of the 3′-neighbored anti conformer were identified and subsequently detected within RNA structures. In a second part, 2′-fluoro-2′-deoxyribose was incorporated at positions with guanosine in unfavored syn orientation. Instead of a changed global fold, the direction of the hydrogen bond network in the modified tetrad was reversed. This first example of tetrad inversion within a unimolecular quadruplex yielded a unique (3+1)-hybrid topology with only homopolar stacking interactions. Additionally, the effect was reproduced for another sequence and high-resolution structures were determined. Unfavored interactions between the 2′-fluorine and the narrow groove of the quadruplex were identified as a reason for different sugar conformations and consequent structural rearrangements.
The overarching goal of this work was to develop a biosensor based on functional nucleic acids. The biosensor should be modular, such that by exchange of the recognition unit, tailored biosensors could be created, allowing detecting a variety of analytes on demand. In the context of the cooperation with a company, initially, TNFalpha was chosen as an analyte. In a previous work, it was tried to build a modular aptazyme for TNFalpha that was based on four aptamers that were developed by SELEX. Here, these aptamers were investigated more closely by different methods (SPR, QCM). In the present work, it was proven beyond doubt that this attempt was not feasible. The aptamers were not able to bind the biologically active form of TNFalpha. An even more interesting finding was that a common tool to immobilize molecules to investigate their interactions with a binding partner, namely the streptavidin-biotin interaction, can strongly influence the result of the assay and causing false-positive results. Afterwards, it was decided to continue the work with a DNAzyme and modular approach was strictly refrained. It was tried to build aptazymes for TNFa or creatinine by in vitro selection, which failed. Most likely, the crucial factors were the ligands itself and the high demand on in vitro selection to select two functionalities (aptamer and catalytic activity) in parallel. This was the reason, to develop a new and a different method with streptavidin as a model analyte. The new strategy was to combine in vitro selection and rational design. The 17E-DNAzyme was chosen as catalytically active module. In preparation of the in vitro selection work, its properties were analyzed. An oligo-based inhibitor of the 17E-DNAzyme was rationally designed and its functionality was experimentally evaluated. Then, a library was designed which contained the 17E-DNAzyme, a randomized domain, and the inhibitor and its functionality was experimentally proven. The in vitro selection for the aptamer and the catalytic function were separated in two steps where the substrate strand was introduced in the second step. The knowledge about in vitro selection procedures, which was gained in the first trials with TNFalpha and creatinine was applied and could be substantially broadened. The crucial factors for the success of this process were identified. Most important steps are the amplification steps between the rounds and the in vitro selection pressure. The template concentration in the PCR has to be very low; the selection pressure has to be high. However, in fact, the exact quantity of "low" and "high" is difficult to determine exactly, it has to be individually evaluated for every amplification step, and this makes in vitro selection a method that requires a lot of experimental skills, optimization procedures, and experience. An EMSA was established and performed to qualitatively prove the affinity of the library for streptavidin in the first step of the in vitro selection method. For the second step, the in vitro selection of the catalytic function, considerable effort was done, but the in vitro selection did not succeed. Using the Biacore, the dissociation constant of the pool, which was applied in the second step of in vitro selection, was determined to be KD = 38 nM. This is very low, and by sequencing the pool it was found that the sequence variability was too low. The sequences share a cramp-like stem-loop structure, which hold the DNAzyme in an inactive conformation. This work presents valuable results for the development of biosensors based on nucleic acids, applying in vitro selection and rational design. Aptamers for streptavidin were selected. The library, which was used for this in vitro selection was structurally constrained. This obviously, represented an exceptionally good starting point for the in vitro selection. In this work, a lot of information about the development of in vitro selection systems was gained. Important work was done on establishing a click chemistry-based immobilization strategy. This work is going to fundamentally facilitate a new in vitro selection approach based on this immobilization strategy.
Chiral amines represent high-value fine chemicals serving as key intermediate products in pharmaceutical, chemical and agrochemical industries. In the past decades, application of amine transaminases (ATAs) for stereoselective amination of prochiral ketones emerged to an environmentally benign and economically attractive alternative to transition metal-catalyzed asymmetric synthesis to afford optically pure amines at industrial scale. However, the restricted substrate scope of wild-type transaminases prohibited the conversion of particularly sterically demanding substrates, making protein engineering indispensable. The following thesis covers elaboration of a novel assay for transaminases (Article I) and identification and development of transaminase variants in order to achieve biocatalytic preparation of a set of pharmaceutically relevant model amines, ideally in optically pure form for both stereoisomers, preferentially using asymmetric synthesis and most preferably using isopropylamine as cost-efficient amine donor co-substrate (Article II-IV). The aforementioned target amines and the corresponding precursor ketones (see Scheme 4.1) were conceived and provided by the company F. Hoffmann-La Roche to attain suitable biocatalysts for a variety of potential intermediates for active pharmaceutical ingredients. Protein engineering of the transaminase scaffolds investigated in this thesis comprised: Initial screening for suitable starting enzyme scaffolds, structure-guided rational design of these scaffolds to enable bulky planar substrate acceptance, elaboration of a sequence motif, verification of the motif and preparative-scale asymmetric synthesis reactions (Article II). For non-planar and structurally different target substrates, namely spatially bulky or bi-cyclic bridged substrates, the transaminase variants were specifically refined and a different evolutionary route had to be pursued (Article III and Article IV). These results (Article II) represent not only the first successful endeavor to engineer a PLP-fold type I amine transaminase (commonly denoted as (S)-selective) for the conversion of highly sterically demanding substrates, but also generally expanded the scope of available fold type I amine transaminases by enzymes having a novel and exceptionally broad substrate spectrum. Aside from structure-guided rational protein engineering, as well non-rational methods, such as site-specific saturation mutagenesis or directed evolution, were applied for protein-engineering. In order to do so for all of the target compounds, a novel high-throughput solid phase activity assay for transaminases that was actually developed during the master thesis, was refined and published (Article I). In the context of this thesis, the same assay principle was as well adapted for quantification of specific activities in liquid phase (Article III). A comparison of different methodologies for developing agar plate assays and a detailed step by step protocol of our transaminase assay are illustrated in a book chapter.
In this work, the discovery, expression and characterization of new eukaryotic Baeyer-Villiger monooxygenases (BVMOs) from yeasts has been shown. A rational design of one of these enzymes led to the identification of key residues to alter the sulfoxidation activity of this group of enzymes. Additionally, in another rational design approach, the cofactor specificity of the BVMO cyclohexanone monooxygenase from Acinetobacter calcoaceticus could be substantially altered to accept the much cheaper and therefore industrially more relevant cofactor NADH.
In this work, the regioselectivity of different Baeyer-Villiger monooxygenases (BVMOs) for the conversion of selected substrates was reversed or improved by protein engineering. These studies highlight the importance of substrate positioning for the regioselectivity and that the position of the substrate can be efficiently influenced by introducing proper mutations. It was shown that the beneficial mutations for all BVMOs were partly in corresponding positions. Additionally, the sulfoxidation activity and the stability of BVMOs were targeted and improved by applying protein engineering.
Streptococcus pneumoniae (pneumococci), a human pathobiont, express and expose several proteinaceous colonization and virulence factors on its surface to facilitate on the one hand colonization of the upper respiratory tract and on the other hand pathogenesis in the host. In this study the interaction of two of such factors referred to as pneumococcal virulence factor A (PavA) and pneumococcal virulence factor B (PavB) and acting as microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), was delineated with the two host matricellular proteins fibronectin (Fn) and vitronectin (Vn). Despite similarity in nomenclature, PavA and PavB represent two diverse pneumococcal proteins with respect to their structure and association with the pneumococcal surface. PavA is a non-classical surface protein (NCSP) with an ambiguous mode of secretion and anchorage while PavB is a characteristic MSCRAMM, anchored via sortase A to pneumococcal peptidoglycan. PavB has a signature of repetitive modules termed as streptococcal surface repeats (SSURE). Pneumococci preferentially interact with immobilized human Fn. In vitro cell culture adherence assays demonstrated that cell bound Fn facilitates the adherence of pneumococci to the host cells and this particular interaction is indifferent to host cell type and is species non-specific. Flow cytometry and immunoblot analyses further indicated the ability of pneumococci to interact with the soluble form of Fn in a dose-dependent but species non-specific manner. The molecular interaction of PavA and PavB (via its SSURE domains) with Fn was delineated further in detail via several direct protein-protein interaction approaches. Ligand overlay assays, surface plasmon resonance studies and SPOT peptide arrays demonstrated that PavA and PavB target at least 13 out of the 15 type III fibronectin domains located in the C-terminal part of Fn. Strikingly, both pneumococcal fibronectin-binding proteins (FnBPs) recognize similar peptides in targeted type III repeats. Structural comparisons revealed that the targeted type III epitopes cluster on the inner strands of both β-sheets forming the fibronectin domains. Importantly, synthetic peptides of FnIII1, FnIII5 or FnIII15 bind directly to FnBPs PavA and PavB, respectively. Thus, analysis of interaction of pneumococcal FnBPs PavA and PavB revealed a probable conserved and/or common pattern of molecular interaction with human Fn. In addition to Fn, pneumococcal PavB interacts with other host matricellular proteins such as human plasminogen (Plg) and human thrombospondin-1 (hTSP-1). Pneumococcal proteins such as PspC and PspC-like Hic have earlier been demonstrated to interact with hTSP-1 as well as human Vn, thereby depicting a redundant function as MSCRAMMs. In this study the role of PavB as a pneumococcal vitronectin binding protein (VnBP) was assessed. Flow cytometric analysis suggested PavB as VnBP, because strains deficient for PavB exhibited a significantly decreased ability to acquire vitronectin compared to wild-type pneumococci. When using a double knockout, deficient in expression of PavB and the VnBP PspC, the pneumococcal interaction with vitronectin was completely abolished. The direct protein-protein interaction assays such as far western ligand overlay, ELISA, and surface plasmon resonance indicated the interaction of SSURE domains with both soluble and immobilized Vn. However, the binding activity depends on the number of SSURE domains with five SSURE showing the highest binding activity to Vn. The interaction of PavB with Vn was charge dependent and heparin sensitive as analyzed by ELISA. The importance of the heparin binding domains of Vn in this interaction was further analyzed via direct protein-protein interaction approaches. Binding studies (far western ligand overlay, ELISA, and surface plasmon resonance) with truncated recombinant Vn fragments indicated that PavB targets the C-terminal heparin-binding domain (HBD3) of vitronectin, a characteristic shared with PspC, hence, suggesting a conserved molecular interaction of pneumococci with Vn. In addition to its function as an MSCRAMM, PavB has the capability to interact directly with host epithelial cells via an unknown cellular receptor. Thus, this study aimed to identify cellular receptor(s) for PavB. In vitro cell culture adherence and invasion assays confirmed that pneumococcal PavB is involved in promoting pneumococcal adherence to respiratory epithelial cells without employing any molecular bridge. The direct interaction between PavB and host epithelial cells was further confirmed via direct binding assays when using Cy5-labeled PavB and flow cytometric analysis. Strikingly, exogenously added human vitronectin competitively inhibited binding of PavB to respiratory epithelial cells. This observation led us to hypothesize that the major vitronectin receptor αvβ3 integrin acts as a potential receptor for PavB. This hypothesis was supported by functional blocking assays with monoclonal antibodies recognizing specific integrin subunits. The results revealed reduced binding of PavB in the presence of bound antibodies recognizing αv integrin indicating that PavB employs αvβ3 integrin as its direct receptor on eukaryotic cells. This was further confirmed via a direct binding assay of PavB to mouse embryonic fibroblasts (MEFs) where cells lacking αvβ3 demonstrated a marked decrease in binding to PavB. Although functional blocking assay and direct binding assay with MEFs supported the role of αvβ3 integrin as a direct adhesin for PavB, RNA interference of αv integrin in epithelial cells did not impair the binding of PavB in αv-knocked down cells in comparison to non-transfected cells. Finally, surface plasmon resonance (SPR) analysis indicated the direct interaction between pneumococcal PavB and recombinant αvβ3 integrin. In this study we report for the first time the interaction of a Gram-positive extracellular pathogen, namely Streptococcus pneumoniae, with one of the host ICAMs, namely the αvβ3 integrin. In conclusion, the present study analysed some of the aspects of molecular interaction of pneumococcal MSCRAMMs PavA and PavB with hFn and hVn. The hot spots of interaction on C-terminal FnIII repeats were delineated for PavA and PavB. HBD3 was revealed to be pivotal for PavB-Vn interaction. In addition the redundant role of pneumococcal PavB as an MSCRAMM was demonstrated. Furthermore this study successfully identifies a direct receptor for pneumococcal PavB, namely αvβ3 integrin. The mechanism and biological rationale of this newly identified interaction is a matter of debate and awaits further scientific analyses.
The intracellular life cycle of the human immunodeficiency virus (HIV) is modelled using ordinary differential equations (ODEs). Model parameters are obtained from the literature or fitted to experimental data using parameter estimation procedures. Key steps in the life cycle are inhibited singly and in combination to show the effects on viral replication. The results validate the success of highly active antiretroviral therapy (HAART), and in addition DNA nuclear import is identified as a novel influential therapeutic target.
Forests are and have been of major importance to cover a variety of societal needs. Today the demands on forests are ever increasing with sequestering carbon and balancing the climate, to name only a few. To cover those requirements forests need vital, productive, and sustainable. A difficult concept as such as the understanding of a healthy forest varies greatly. Nevertheless, forests still have to produce a sufficient amount of yield while threatened by changing climate conditions. These are predicted to bring extended and more intense drought periods as well as a higher frequency of storms and the promotion of secondary disturbances like insects calamities to also rise. In this complex situation of high and versatile demand the focus is on the allocation of the “right” forest. Forest management is requested to balance the needs of humans against those of wildlife against those of the trees themselves. To gain the respective knowledge on species responses and provenance growth, now and in the future research gaps need to be closed. All factors influencing tree growth and therefore ultimately yield need to be understood and special focus needs to be on the interactions within the forest ecosystem. One of the parameters in understanding aggregated tree growth is the dynamic of growth. This can be visualised by dendroecological methods, providing a picture of growth within the individual years. Growth dynamics are dependent on multiple factors, some, like soil being preconditioning and other like climate causing short-term responses. In this thesis I focus on the influence of climate on annual tree growth using a new approach of daily climate data to calculate climate-growth correlations. This method has the advantage of representing tree processes better than the former approach of using monthly means. Furthermore the program enables the user to feed climate scenarios and therefore estimate future growth. To gather information on species as well as provenance differences to provide advice to foresters I used different trials in Britain and Germany. On the British site different oak species were planted while the German sites are stocked with various spruce provenances. For the latter we additionally used stable carbon isotope analysis to calculate intrinsic water use efficiency. The climate-growth correlations revealed differences between the oak species with a generally higher linkage to precipitation than temperature. While the differences are clear, the question of thresholds and the role of extreme events became apparent in this work. VII Abstract Assessing the impact of extreme events using dendrometer data revealed little differences in the response to short term events of the three investigated species, oak, beech, and pine. We were able to pick up stimulus-response-relationships and as a novel result no species-specific responses were found when focusing on such a small time frame. The provenance trials offered the opportunity to investigate the potential of the use of daily climate data more closely. The two contrasting sites planted with six spruce provenances each gave an insight on the adaptive potential of provenances as well as an indication on the response times. Depending on the proceeding environmental and the local climate conditions decisions have to be made on the species or provenance selection. This thesis provides a method as well as insight on the behaviour of the important European species beech, oak, pine, and spruce. It, however, highlights the limitations such methods have for large scale estimates. While general trends on the response to specific soil factors can be used, the climatic responses, be it thresholds or climate-growth correlations can only be seen within the ecological context of their sampling region.
Pharmaceutical residues are found in increasing concentrations in the environment and in potable water where they have verifiable effects on aquatic life. Conventional methods for water treatment are not able to sufficiently abate these generally stable compounds. It was found that physical plasma generated directly in water can degrade several of these recalcitrant organic pollutants. Studies on the basic plasma chemical processes for the model system of phenol showed that the degradation is primarily caused by hydroxyl radicals. This was confirmed by reaction chemistry and spin trap enhanced electron paramagnetic resonance spectroscopy (EPR). The degradation of diclofenac and its by-products were investigated in detail to perform a first risk-assessment of the new technology. Findings are not limited to the application of plasma but applicable to other advanced oxidation processes (AOP) that are based on the generation of hydroxyl radicals as well. Additionally, pulsed corona plasma and pulsed electric fields were assessed for their capacity to kill Legionella pneumophila in water. Whereas it was possible to kill L. Pneumophila with both methods, plasma treatment resulted in an enhanced bacterial killing. Therefore, advanced oxidation processes (AOP) and plasma treatment in particular are some of the few feasible approaches to decompose recalcitrant compounds in water.
Investigation on the primary and secondary metabolism of marine and terrestrial endosymbionts
(2017)
Ph.D. thesis describes the metabolism of marine fungus and isolation of natural product for human use in part I and also describes earthworm endosymbiosis mechanism in part II. From the marine fungus project, three new producers have been identified for the previously reported bioactive secondary metabolites. And, from the Earthworm endosymbiosis project, the role of primary metabolites in the host fitness has been partially studied. the results outcome will be a partial contribution to microbial symbiosis.
Estimating effects of craniofacial morphology on gingival recession and clinical attachment loss
(2017)
Objectives: Currently, evidence for the association between face morphology, attachment loss and
recession is lacking. Face type can be described by the ratio of facial width and facial length. We
hypothesize, that the facial type might be related to gingival recession (REC) and clinical attachment
loss (CAL) and that a broad face is associated with less recession and attachment loss than a long
face.
Materials and methods: Data from the 10 year follow-up of the Study of Health in Pomerania
(SHIP-2; 2008-2012; 2333 participants) were used. Periodontitis was assessed by probing depth (PD)
and clinical attachment loss (CAL). Generalized regression models were used to assess associations
between specific landmark distances extracted from magnetic resonance images (MRI) head scans
and clinically assessed gingival recession adjusting(REC) or clinical attachment loss(CAL) adjusting
for relevant confounders.
Results: Maximum cranial width was negatively associated with mean REC and mean CAL
(p<0.05). Also, higher mean REC and higher mean CAL correlate positively with long face
(B=0.361 with 95% CI), upper anterior facial height.
Conclusion: According to the results of the present study, gingival recession and clinical attachment
loss were associated with higher Prosopic face and facial length indices results.
Aiming at the goal of individualized medicine, this dissertation develops a generic methodology to individualize risk factors and phenotypes via metabolomic data from the urine. As metabolomic data can be seen as a holistic representation of the metabolism of an organism at certain time point, metabolomic data contain not only information about current life-style factors like diet and smoking but also about latent genetic traits. Utilizing this integrative attribute, the dissertation delivers a metric for biological age (the metabolic age score) which was shown to be informative beyond chronological age in three independent samples. It was associated with a broad range of age-related comorbidities in two large population-based cohorts, predicted independently of classical risk factors mortality and, moreover, it predicted weight loss subsequently to bariatric surgery in a small sample of heavily obese individuals.
Subsequently to this work, the dissertation built a definitional framework justifying the procedure underlying the metabolic age score, delivering a general framework for the construction of individualized phenotypes and thereby an operationalization of individualization in statistical terms. Conceptualizing individualization of the process of differentiation of individuals showing the same phenotype despite different underlying biological traits, it was shown formally that the prediction error of a statistical model approximating a phenotype is always informative about the underlying biology beyond the phenotype if the predictors fulfill certain statistical requirements. Thus, the prediction error facilitates the meaningful differentiation of individuals showing the same phenotype. The definitional framework presented here is not restricted to any kind of data and is therefore applicable to a broad range of medical research questions.
However, when utilizing metabolomic data, technical factors, data-preprocessing, pre-analytic features introduce unwanted variance into the statistical modeling. Thus, it is unclear whether predictive models like the metabolic age score are stable enough for clinical application. The third part of this doctoral thesis provided two statistical criteria to decide which normalization method to remove the dilution variance from urinary metabolome data performs best in terms of erroneous variance introduced by the different methods, aiding the minimization of biological irrelevant variance in metabolomic analyses.
In conclusion, this doctoral thesis developed a general, applicable, definitional framework for the construction of individualized phenotypes and demonstrated the value of the methodology for clinical phenotypes on metabolomic data, improving on the way the statistical treatment of urinary data regarding the dilution correction.
Staphylococcus aureus (S. aureus) is the leading cause of serious diseases in human both from hospital and community associated infections. Some clinical manifestations of S. aureus infections are infective endocarditis (IE), osteoarticular infections, skin and soft tissue, pleuropulmonary, and device-related infections. In Germany, S. aureus is the second most common cause of hospital-acquired (HA) infections. About 16.7% of these nosocomial infections are caused by HA-MRSA clinical isolates. It has been a huge threat for the clinicians/scientists to control the emergence of such infections caused by S. aureus. S. aureus exhibits increasing virulence and resistance to various antibiotics, complicating prevention and treatment of infections. Eventually, active and passive vaccines might be the alternative strategy to deal with S. aureus related diseases. An effective S. aureus vaccine would provide great potential security and many societal benefits. However, so far vaccine trials have failed often due to limited number of available antigen candidates (monovalent/single antigen) in the clinical trials. Efforts to develop not only S. aureus vaccine but also prognosis or diagnosis tools are challenging tasks. That was the motivation point for the current thesis to identify potential antigen candidates for the aid of vaccine development using immunoproteomics approaches. From the earlier studies, passive immunisation with CP5, CP8, PNAG, ClfA, SdrG, alpha-hemolysin and active immunisation with IsdB, SEB, ClfA, CP5, CP8 were examined during preclinical trials and found to be the best examples for potential vaccine candidates. The antibody responses against S. aureus infections are heterogenous, still it is possible to identify the antibody signatures to a number of corresponding S. aureus antigens, whose abundance and presence could correlate to the disease state and may predict treatment outcome. To support this hypothesis, goals were set to develop and validate serological assay by indirect detection using suspension array technology (SAT). During the study, an antigen library of 140 recombinant S. aureus antigens was generated. Further serological assay were developed and validated to monitor the insights of antibody mediated humoral responses during S. aureus infection from various episodes of S. aureus infection. As an outcome, potential immunogenic antigen candidates were identified which may be used as candidates in active/passive vaccination and to stratify the patient. In total, three studies were carried out using serum and plasma samples from S. aureus nasal colonised healthy individuals (carriers and non-carriers) and bacteraemia patients (control, complicated and uncomplicated sepsis). Bead-based assays were performed and subsequent statistical analyses were done to identify immunogenic antigens that might discriminate between the different clinical status and outcome. Screening of healthy individuals (study-1) have shown significantly higher IgG responses against 14 antigens in S. aureus nasal carriers compared to non-carriers. Furthermore, the clonal complex 30 group of healthy carriers has shown significantly higher IgG responses against toxic shock syndrome toxin-1 (Tsst1) in comparison to non-clonal complex 30 healthy carriers. Study-2 have shown extensively higher IgG responses against 67 antigens in control samples compared to sepsis patients. 50% of the antigens eliciting different immune responses belonged to the extracellular components of S. aureus. The IgG responses against MSCRAMM proteins such as FnbA, FnbB, Efb-1 have been shown to be significantly higher in complicated sepsis. Study-3 have shown notably higher IgG responses against 8 antigens (Plc, SspB, IsaA, SEM, GlpQ, HlgC, SACOL0444, SACOL0985) at baseline in uncomplicated sepsis patients compared to patients subsequently developing complicated sepsis. In summary, the group of immunogenic antigens that have been identified in these studies using immunoproteomics approach could be a starting point for the development of S. aureus vaccines. Moreover, the suspension array technology approach facilitated the identification of new S. aureus antigen candidates in addition to earlier reports. The current results of this study support the hypothesis that it is possible to identify a serological response to potential S. aureus antigens that correlate to progression of S. aureus infections.
The thyroid as the largest endocrine gland mainly produces and secretes the thyroid hormones (TH): 3,3’,5-triiodo-L-thyronine (T3) and its pro-hormone L-thyroxine (T4). Besides the impact on growth, normal development, bone marrow structure, the cardiovascular system, body weight and thermogenesis, TH play a vivid role in many metabolic regulatory mechanisms in almost all tissues. Thyroid diseases are relatively prevalent and cause, due to the resulting TH imbalances, a broad spectrum of effects. Many of them manifest in pathologically increased or decreased TH levels defined as hyperthyroidism or hypothyroidism, respectively. Routinely, determination of the thyroid state is based on the assessment of the classical markers TSH and free T4. However, this practice has several drawbacks. Moreover, elucidation of the pleiotropic effects of TH on multiple molecular pathways is mostly based on cell culture, tissue and rodent models. Analysis of animal biofluids like serum and urine using metabolomics approaches demonstrated the extensive impact of TH on other body compartments. In contrast, proteome profiling has not been exploited for the comprehensive characterization of the general metabolic effects of TH. Plasma as a large and diverse compartment of the human proteome provides a great opportunity to identify novel protein markers of thyroid function as well as to characterize metabolic effects of TH in humans.
Therefore, a study of experimental thyrotoxicosis was performed with 16 male volunteers treated with 0.25 mg/d levothyroxine (L-T4) for 8 weeks to induce a hyperthyroid state. Plasma samples were collected before the L-T4 application started, two times during the treatment and additionally two times after withdrawal. Proteome analysis revealed remarkable alterations including increased levels of two known proteins known to correlate with TH levels (sex hormone-binding globulin and cystatin C). The correlation with free T4 levels revealed 76 out of 437 detected proteins with a Pearson correlation coefficient of r ≥ |0.9|. One prominent signature included 10 coagulation cascade proteins exhibiting significantly increased plasma levels during thyrotoxicosis, thereby revealing a trend towards a hypercoagulative state in hyperthyroidism. To overcome the statistical drawbacks of the Pearson correlation analysis, additionally a mixed-effect linear regression model using serum free T4 concentrations as exposure and protein abundances as outcome while controlling for age, BMI, and batch was implemented. Application of this model resulted in the detection of 63 proteins with significant associations to free T4 levels. Besides the already mentioned augmented coagulation, a significant drop in the amounts of three apolipoproteins (ApoD, ApoB-100 and ApoC3) was observed. Furthermore, an increased abundance of proteins assigned to the complement system was detected.
Experimental studies in humans were complemented by corresponding analyses in murine models. In the current work, plasma samples of two murine studies including male C57BL/6 wildtype mice were analyzed to elucidate the impact of thyroid dysfunction on the plasma proteome. The first study was similarly designed as the human model of experimentally induced thyrotoxicosis and assigned the animals to three groups: a control group, a T4 treatment group, and a T4 recovery group, whereupon the latter first received T4 followed by a subsequent TH normalization period. A high proportion of plasma proteins exhibited significantly different protein levels during T4 application (n = 120), where 90 of these also showed a corresponding reverse trend after T4 withdrawal (T4 recovery vs. T4), thereby displaying transient alterations. The molecular pattern of hyperthyroidism in the murine model indicated, as in the human study, a pronounced decrease in apolipoproteins. However, in clear contrast to the human data, the levels of proteins related to the coagulation cascade and complement system were also transiently decreased in mice, while being increased in humans.
The second murine analysis focused on the impact of hyper- and hypothyroidism caused by T3 or T4 treatment and MMI/KClO4 application, respectively. In general, compared to the first murine study less clear alterations of protein levels were detected. Proteins related to the complement system revealed fewer changes in the T3 group and only marginal changes after T4 induction. Unexpectedly, the MMI/KClO4-induced hypothyroidism caused a reduction of the levels of several proteins assigned to the complement system, although different components and factors were affected.
Generally, rodent studies partially provided a divergent picture of TH action as compared to human studies. However, in spite of inconsistent results in studies regarding the effects of TH that are possibly due to species-specific differences, an important role of TH on several metabolic and other pathways, e.g. in the process of blood coagulation and apolipoprotein regulation, is evident. The results from both murine and human studies presented here provide novel insights into changes in the plasma proteome in the context of thyroid diseases which might contribute to a better understanding of TH action on metabolism and other pathways.
Body sensations play a crucial role in the etiology and maintenance of diverse anxiety and health problems (e.g., in panic disorder or respiratory diseases) as they may be perceived as threatening and consequently elicit anxious responses. The factors that may affect the perception of bodily sensations as a threat and thus modulate the anxious response to body sensations have so far rarely been studied. Therefore, the present thesis targeted at elucidating the effect of contextual (i.e., the predictability, expectation, and proximity of a threat) and dispositional factors (i.e., tendency to fear arousal sensations or trait fear of suffocation) on the defensive response to body sensations.
In study 1, it was investigated how a personality factor, that is, fear of suffocation, affects the acquisition of fear to body sensations (i.e., mild dyspnea induced by inspiratory resistive loads) and contexts when faced with a predictable and unpredictable respiratory threat (i.e., severe dyspnea). Study 2 aimed at examining the main and interactive effects of the tendency to fear arousal sensations, again a personality trait factor, and current arousal expectations as varied by situational variables on anxious responding to arousal sensations. In this study, expected and unexpected arousal sensations were induced by administering caffeine in coffee or bitter lemon soda, respectively. Moreover, in study 3, it was explored how subjective anxiety, bodily symptoms, and defensive respiratory responses change and might culminate into active defense behavior (i.e., escape/active avoidance) during increasing dyspnea that was evoked by inspiratory resistive loads increasing in intensity. For a detailed analysis of the factors that contribute to the initiation and maintenance of avoidance of or escape from increasing dyspnea, in study 4 changes in subjective, autonomic, somatic reflex and brain responses were analyzed during repeated avoidance of increasing dyspnea.
In study 1, it was demonstrated that only individuals who fear suffocation learned to fear mild dyspnea preceding the onset of severe dyspnea and developed anxiety during a context of unpredictable respiratory threat. Moreover, the data from study 2 indicate that individuals who fear arousal sensations show an increased attention allocation towards unexpected arousal sensations and higher threat appraisal when expecting arousal sensations. Increasing intensity of dyspnea as provoked in study 3 led to increased defensive respiratory responses that were associated with increased symptom reports in individuals with high compared to low fear of suffocation. Moreover, culminating dyspnea elicited repeated avoidance behavior preceded by increases in defensive respiratory mobilization. The analysis of repeated avoidance of increasing dyspnea in study 4 revealed that physiological fear responses might be involved in the initial initiation of this avoidance behavior while no indication of response preparation and physiological arousal was related to persistent avoidance.
Taken together, the present data suggest that the fear of suffocation, as well as the tendency to fear arousal sensations along with the predictability, expectation, or proximity of interoceptive threat, may increase the perceived threat and thus the anxious response to body sensations. Therefore, contextual and dispositional factors may set the stage for the culmination of body sensations into defensive action and might contribute to the development of pathological anxiety and fear of body sensations. The present findings are integrated into the current literature and discussed in relation to the development and maintenance of pathological anxiety and fear of body sensations.
Psychological health is a result of the effective interplay between explicit and implicit attempts to regulate ones’ emotions (Koole & Rothermund, 2011). Emotion regulation refers to processes that influence the intensity, the duration and the type of emotion experienced (Gross & Thompson, 2007). While explicit emotion regulation comprises effortful mental processes, implicit emotion regulation refers to processes that require no monitoring and terminate automatically (Gyurak, Gross, & Etkin, 2011).
In the present thesis, explicit and implicit strategies to regulate emotions were investigated. In Study 1, a well-established paradigm (Gross & Levenson, 1993) was adapted to examine the up- and down-regulation of positive and negative emotions using two different explicit emotion regulation strategies. To infer on the neurobiological correlates, blood oxygen level dependent (BOLD) brain activity was recorded using functional magnetic resonance tomography. Furthermore, as a trait marker for the individual ability to regulate emotions, heart rate variability (HRV) was acquired during rest. In Study 2, implicit emotion regulation was examined. Therefore, a well-established fear extinction paradigm was compared to a novel approach based on the integration of new information during reconsolidation (Schiller et al., 2010). Autonomic arousal was measured via the skin conductance response during fear acquisition, fear extinction and after fear reinstatement. In Study 3, two dysfunctional emotion regulation strategies —worrying and rumination— were investigated. Excessive worrying and rumination are pathogenic characteristics of psychological disorders. Behavioral, autonomic and BOLD activity was recorded during worried and ruminative thinking as well as during neutral thinking.
The results showed that explicit emotion regulation was associated with modulated BOLD activity in the amygdala according to the regulation direction independent of the applied strategy and the valence of the emotion. In addition, increased dorsolateral prefrontal cortex (dlPFC) activity was observed during regulation compared to passively viewing emotional pictures. The findings are in line with previous research (Eippert etal., 2007; Kim &Hamann, 2007; Ochsner etal., 2004) and support the key role of the dlPFC during the explicit regulation of emotions. Similarly, implicit emotion regulation was associated with a decreased autonomic fear response, which was sustained after fear extinction during reconsolidation. The findings underscore the notion, that this novel technique might alter the initial fear memory resulting in a permanently diminished fear response (Nader, Schafe, & LeDoux, 2000; Schiller et al., 2010). Dysfunctional emotion regulation was associated with increased autonomic activity and fear potentiated startle (during worry) as well as increased BOLD activity in the insula (during worry and rumination) and increased BOLD activity in the amygdala (during rumination). In addition, neural activity in brain areas associated with the default mode network was observed. These findings stress the preserved negative emotional activity and the self-referential nature of the examined dysfunctional strategies. The results of all three studies are integrated into a neuro-biological model of emotion regulation focusing on the interplay between subcortical and prefrontal brain areas.
There is multiple evidence that emotionally arousing events are preferentially processed, and better remembered than neutral events. In the present dissertation I investigated whether those strong emotional memories are affected by acute and chronic stress. Moreover, I was interested in whether already established emotional memories can be changed by behavioral intervention. According to the modulation hypothesis, emotionally arousing events promote attention and memory processes via noradrenergic and glucocorticoid actions. Recent models suggest that stress hormones differentially impact mnemonic processing, namely encoding, (re-) consolidation and memory retrieval, depending on timing and duration of the stressor relative to the learning experience. Acute stress around the time of encoding has been found to enhance memory, whereas chronic stress has been associated with memory impairments. Furthermore, consolidated memories are not resistant to modifications. Following reactivation, memories can turn into an unstable state and undergo a process called reconsolidated in order to persist. During this vulnerable state, memories are prone to modification, for instance by pharmacological blockade or interference learning. Here, the modulation of newly formed emotional and neutral memories as well as existing emotional and neutral memories was investigated in a well-established picture viewing and recognition memory paradigm using behavioral and neurophysiological measures (event-related potential, ERPs). More elaborative processing of emotional, relative to neutral stimuli has been related to the late positive potential (LPP). During encoding of emotional and neutral pictures, enhanced LPPs (starting at about 400 ms after stimulus onset) are usually observed for emotionally arousing relative to neutral pictures, indicating preferential attention allocation and processing. During recognition, correctly recognized old items evoke larger ERP amplitudes than correctly identified new items. This difference, the ERP old/new effect, was used to measure mnemonic processing during retrieval. The ERP old/new effect over centro-parietal sensor sites (400-800 ms) has been associated with recollection processes, and is enhanced for emotional, compared to neutral materials. Three studies are presented, that investigated 1) the influence of acute stress prior to encoding on long-term memory and its neural correlates, 2) the impact of chronic stress on encoding and memory, and 3) the influence of interference on already established memories (reconsolidation), always contrasting emotionally arousing and neutral scenes. Study 1 investigated subsequent recognition memory after encoding following acute stress using a socially evaluated cold pressure test, while study 2 tested the influence of chronic stress investigating breast cancer survivors about two years after cancer treatment. In study 3, one day after encoding, reconsolidation of the reactivated picture memory was targeted with an interfering learning task. In all three studies, recognition memory was tested one week later. High-density electroencephalograms (EEGs; 257 electrodes) were recorded to measure brain potentials. The results showed, in line with previous research, that emotionally arousing scenes were preferentially processed, as indicated by larger LPPs, and were better remembered than neutral scenes, as indicated by enhanced memory performance and larger ERP old/new differences. Experiencing acute stress prior to encoding enhanced the centro-parietal ERP old/new effect for emotionally arousing pictures at recognition, corroborating that acute stress facilitates memory for emotional scenes (Study 1). In contrast, attenuated LPPs for unpleasant pictures and impaired memory performance for arousing pictures were observed in breast cancer survivors (Study 2), indicating altered attention to emotion and subsequent emotional memory storage in chronically stressed individuals. When memory reactivation was followed by an interfering learning task, recognition memory and ERP old/new differences were attenuated for emotionally arousing scenes, selectively, showing the possibility that emotional memories might be modulated by behavioral interventions (Study 3). The results of all three studies are discussed and integrated into a model of memory modulation by stress and interference. The results highlight the importance of understanding the role of emotional arousal in the processes of memory formation, retrieval and reconsolidation. Moreover, shedding light on the differential effects of acute and chronic stress, interference and their possible interactions might help to prevent and even modify impairing memories that are one of the major concerns in stress- and fear-related mental disorders.
Interoceptive sensations, that means, perceptions of the physiological body state, play an important role in the generation and expression of emotion. The focus of the research presented here is on respiratory sensations as specific interoceptive signals. Such respiratory sensations (like the feeling of dyspnea) play an important role in symptom perception in somatic (e.g., asthma) as well as in mental disorders (e.g., anxiety disorders). There are several different ways to manipulate respiratory sensations in an experimental environment, but many of them did not equal sensations in daily life. Here, stimuli (inspiratory resistive loads, caffeine) were used that trigger nearly naturally occurring interoceptive sensations. Taking into account that the elicited interoceptive experience also induces an unpleasant feeling state it is most likely that individuals show defensive physiological responding to such cues and try to avoid them. According to a bidirectional motivational system defensive behaviors are regulated by a defensive motivational system that is activated by threatening cues. From research with exteroceptive stimuli it is known that defensive responding is typically characterized by heightened autonomic arousal, increased respiration, and a potentiated startle eyeblink response. In contrast, only a few studies using interoceptive stimuli have incorporated the measurement of physiological data in their experimental designs. If included, studies show also heightened autonomic responding, whilst a heterogeneous respiratory as well as startle eyeblink responding is observed. Thus, the studies presented here were designed to clarify the factors that mediate defensive responding to interoceptive sensations. Study 1 investigated the influence of anxiety on the subjective, respiratory, and autonomic response to an individually determined inspiratory resistive load, while study 2 focuses on the effect of attentional modulation of the startle eyeblink response to a mild respiratory threat. In study 3 the modulation of subjective, respiratory and autonomic reactions by arousal expectations was examined. Therefore, caffeine, a respiratory stimulant, or a placebo were administered without the participants’ knowledge. The fourth study examined the influence of the process of worrying, a strategy to deal with unpleasant body symptoms, on defensive responding. Depending on the study design subjective, respiratory and autonomic (skin conductance level, heart rate) parameters were assessed as marker for defensive mobilization. In study 2 and 4 the startle eyeblink response was measured as further index of defensive activation. Besides that in study 2 also the P3 component of the event-related potential, as an index for attentional allocation, was recorded. The main findings of the presented dissertation are the following: Study 1 revealed that 1) only high anxiety sensitive individuals reporting also high suffocation fear respond to lower stimulus intensities with stronger defensive responding, and 2) that this group demonstrated a maladaptive compensatory breathing pattern. Additionally, study 2 exhibited that 1) the startle eyeblink response is relatively inhibited during a mild interoceptive threat, and 2) this inhibition corresponds to an attention allocation towards breathing as indicated by a reduced P3 amplitude to the startle noise as well as subjective report. Furthermore, highly anxiety sensitive individuals showed a more pronounced defensive responding if the interoceptive sensations were unexpected (study 3). Recently, study 4 demonstrated that worry led to an increased defensive response mobilization. All studies are discussed in the context of the theoretical background of the defensive response modulation to exteroceptive and interoceptive sensations with respect to mediating factors. Showing exaggerated defensive responding and maladaptive adaptation processes in high anxious individuals the results point towards the important role of interoceptive sensations in the etiology, maintenance and therapy of mental disorders, especially the anxiety disorders.
Lead-cluster investigations
(2017)
In this thesis, investigations on lead clusters stored in a Penning trap are presented. The measurements are performed at the ClusterTrap setup at the Institute of Physics of the University of Greifswald. A Penning trap with a superconducting magnet (B=12 Tesla) makes up the central part of the experiment. In this trap, singly positively or negatively charged lead clusters (a group of lead atoms) are stored, their amplitudes of motion are cooled, and a specific cluster size is selected. Thus, clusters of only a single size are prepared for experimental investigation. After interactions with electrons and/or photons, the trap content is extracted and analyzed by time-of-flight mass spectrometry.
In the first experiment, the size-selected clusters are excited by a frequency-doubled Nd:YAG laser, which leads to fragmentation processes. The preferred fragmentation pathway, which is observed to be break-off of a seven-atom neutral cluster is unusual for metal clusters, which typically evaporate monomers. Furthermore, the already known magic cluster sizes are observed.
In a subsequent experiment, positively charged lead clusters with 31 atoms are irradiated with laser light and fragmentation processes are time resolved investigated. The assumption that lead clusters fragment by break-off of neutral heptamers is confirmed.
In the following experiment, an electron beam is guided through the Penning trap to ionize pulsed-in argon atoms. While the positive argon ions leave the trap, the secondary electrons are trapped together with the selected lead clusters. This allows the electrons to attach to the singly charged lead clusters, which leads to multiply negatively charged lead clusters. The relative abundance of multiply-charged clusters is measured with respect to the cluster size, from which the appearance sizes of di- and trianions can be calculated. In addition to the attachment of electrons, fragmentation products similar to those of the photoexcitation measurements are observed. Furthermore, the cluster sizes 10 and 12 are observed regardless of the investigated precursor size, together with clusters of the precursor size reduced by 10 and 12. This is a first hint for a fission process of doubly negatively charged lead clusters into two singly charged products. In a following measurement, doubly charged lead clusters are produced and photoexcited. The observed abundance spectra confirm this assumption.
Introduction: Antiseptics are used for the prophylaxis of infections of acute wounds and for the treatment of critically colonized chronic wounds as well as localized infections of acute and chronic wounds. If an antiseptic with too much tissue toxicity and/or too little efficacy is used, the wound healing can be delayed.
Objective: The aim was to compare the irritation potency of frequently used wound antiseptics by using the hen's egg test on the chorioallantoic membrane (HET-CAM). Additionally, the influence of antiphlogistic active additives which might increase the tolerability was examined. To allow a more extensive comparison, antiseptics classified as obsolete such as hydrogen peroxide, creams on PVP- iodine base, silver sulfadiazine, chlorhexidine and nitrofural as well as the non-antiseptic wound treatment agents dexpanthenol and hemoglobin spray were also examined.
Method: The HET-CAM was used as a semi-in-vivo method to test the tolerability of wound antiseptics to tissues by observing the reactions that occur in the blood vessels of the highly vascularized CAM such as hemorrhage, lysis and coagulation. The irritation score (IS) was calculated and differentiated in 4 ranges according to Spielmann (1991).
Results: The vascular injuries of the CAM were considered as an indirect indicator of the tolerability. It is accepted that agents with no or low irritation potential on the CAM are to be preferred in the clinical practice if they are clinically effective.
Severe CAM reaction was observed after short-term application of octenidine based wound gel (active ingredient octenidine 0.05%) (IS: 10.3) and chlorhexidine digluconate 0.5% solution (IS: 9.5). Moderate reaction was observed for the combination of octenidine 0.05% in aqueous solution with panthenol 1.34% and allantoin 0.2% (IS: 8.7), hydrogen peroxide 1.5% in aqueous solution (IS: 6.1) and hydrogen peroxide 0.5% solution (IS: 5.5). Slight reaction was observed for hydrogen peroxide 1.5% solution in combination with sodium thiocyanate 0.698% (IS: 2.6), sodium thiocyanate 0.698% solution (IS: 2.1) and Dermacyn® (active ingredient NaOCl/HOCl each 0.004) (IS: 1.2). Polihexanide 0.04% in Ringer solution (IS: 0.9), Polihexanide 0.05% in Lipofundin, Granulox® (active agent hemoglobin 10%) (IS: 0) and dexpanthenol 5% solution (IS: 0) showed no reaction. In the long-term observation (24 hours after application), Dermacyn® showed the best results (59% of irritation remained alive after 24 hours). The addition of dexpanthenol and allantoin reduced the irritability only slightly, whereas the decrease of IS of hydrogen peroxide by addition of sodium thiocyanate was almost significant (p 0.0596).
Conclusion: It is suggested that agents with no or low irritation potential on the CAM are to be preferred in the clinical practice if they are clinically effective. It is suggested that further in vivo and in vitro studies are to be undertaken with these agents.
Solely regarding local tolerability, polihexanide and hypochlorite are the antiseptic agents of choice of the tested preparations. The wound oxygenizer hemoglobin spray is tolerated without irritation as well as the negative control 0.9% NaCl solution. Because of their other disadvantages in conjunction with their irritability, the outdated cream formulations on basis of silver sulfadiazine, PVP- iodine, chlorhexidine and nitrofural cannot be recommended for wound antisepsis.