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40-Year Longitudinal Caries Development in German Adolescents in the Light of New Caries Measures
(2019)
This study assessed the 40-year longitudinal caries development in German adolescents in the light of the sixth National Oral Health Survey in Children (NOHSC, 2016) employing initial DMFT (IDMFT), Significant Caries Index (SiC) and Specific Affected Caries Index (SaC). On the basis of the current NOHSC (randomized cluster selection using school list or regional community school surveys, 55,956 12-year-old sixth-graders examined by 482 calibrated community/study dentists) DMFT, SiC, a novel IDMFT including initial lesions (IT) and the recently introduced SaC were calculated and also recalculated for national and international surveys from the last 4 decades. In 2016, 78.8% of children were caries-free (DMFT = 0), 65.5% including IT lesions. The mean DMFT was 0.44 (single components: DT = 0.14, MT = 0.02, FT = 0.29, IT = 0.52) showing a clear association with the school type as marker for the socio-economic status. The mean number of affected teeth in children with DMFT >0 was 2.07 (SaC) in comparison to almost 9 teeth in the 1970s. The current care index on the tooth level was 66.3%, leaving only 7.7% of children with restorative treatment needs. Longitudinally, a continuous caries decline of more than 80%, including the risk groups (SiC/SaC), to an internationally extremely low level was observed. In conclusion, the National Oral Health Surveys reveal a continuous caries decline to a very low caries level in 12-year-old 6th-graders in Germany even if IT lesions are included (IDMFT). In spite of proportional reductions in the risk groups (SiC/SaC), the polarized caries distribution according to socio-economic parameters reveals the need for targeted preventive programmes.
In the present work high density helicon plasma discharges are created and characterized as a promising concept towards the realization of plasma wakefield accelerators to build up electric fields in the order of GV/m to accelerate electrons to energies in the TeV range with proton driving bunches. For such a concept plasma sources are needed that are able to maintain discharges with plasma densities of n_e = 7E20 m^-3 over long distances with a low variation in plasma density. Measurements at the PROMETHEUS-A device are performed for variable parameters, like magnetic induction, RF heating power and filling gas pressure. A CO2 laser interferometer, a laser induced fluorescence (LIF) diagnostic and a reaction rate model are combined to give a full picture. It is shown that in most cases the plasma density is centrally peaked with a high density region +- 5 mm from the center. The peak plasma density increases with increasing filling gas pressure, RF heating power and magnetic induction, limited by the number of neutral particles in low pressure discharges, by the transferred heating power and the increasing recombination and electron quenching rates of argon ions in high filling pressure cases. The increase in plasma density with increasing magnetic induction correlates to the direct proportionality in the helicon dispersion relation. For all investigated operational parameters the time evolution of the helicon discharge shows the same characteristics and is reliably reproducable inside the error bars. The electron temperature is determined by combining the collisional radiative model with line ratio measurements of two spontaneously emitted LIF lines. The low electron temperature regime of 1.2 eV < T_e < 1.4 eV and the electron temperature profiles are consistent with helicon wave heating via collisional power dissipation. The maximum plasma density of n_e = (6 +- 1)E20 m^-3 is measured at high RF power of P_RF = 24 kW, p_0 = 9 Pa filling gas pressure and a magnetic induction of B = 105 mT with a maximum electron temperature at 1.4 eV. At these operational parameters the plasma density peaking time and width are determined to be 270E-6 s and 50E-6 s, respectively. This shows that specific plasma density requirements for the use of a wakefield accelerator are reachable and the duration of the peak plasma density is more than sufficient for a relativistic particle to pass a 1 km long plasma cell. Additionally time-resolved LIF profile measurements for neutral and singly ionized argon were conducted to complement the previously evaluated measurements. The time resolution of the LIF diagnostic was chosen in a way to adequately represent the evolution of densities and to allow full profile measurements over one day. A resolution of 200E-6 s was chosen. The time-resolved neutral and ion metastable densities show hollow profiles with high densities at the edges over the first ms indicating higher ionization levels and increasing electron quenching rates. The metastable densities are highly determined by electron temperature, RF heating power and filling neutral gas pressure and do not reflect the neutral argon evolution. To investigate the influence of neutral depletion on the density evolution and maximum plasma density, the argon neutral and ion ground state densities are determined. Both time-resolved density profiles show a hollow profile with highest densities at the edges over a longer time interval of 3-4 ms. The penetration depths (ionization mean-free paths) indicate increased ionization of neutral argon while dissipating inwards, corresponding well to the theoretical value of lambda = 20 mm. This results in a depletion of neutrals in the center of the discharge, leading to a limitation and a fast decrease of plasma density after the neutrals are partially ionized. The shown refilling effect of neutral argon is too slow to have an important impact. At operation parameters for highest plasma density, the calculated ground states also show a fast increase in density at the end of the discharge after the RF-heating is switched off. This indicates recombination effects to these atomic states and higher ionization levels than ArII in the helicon discharge.
Understanding the fundamental mechanisms in the extracellular matrix of cells (ECM) is crucial for the development of drugs and biomaterials. Therefore, an atomistic model of the extracellular matrix is a cost-efficient way to observe influences of drugs, test the effect of mutations or misfolds in proteins or study the properties of fibril or network-forming peptides.
With this thesis, a refined molecular model of an adhesion complex is proposed that contains collagen, fibronectin and the cell receptor integrin. During the building of the model, major new insights are given for each of these proteins and a powerful protein-folding algorithm is
developed.
This thesis describes experiments with clusters stored in an electrostatic ion trap called Multi-reflection time-of-flight (MR-ToF) analyzer. These devices are established as mass separators and analyzers with high resolving powers and fast processing times. The objective was to characterize an experiment that utilizes such analyzer for cluster research, to this end a laser-ablation ion source was combined with an MR-ToF analyzer.
In the first part, an experiment scheme that combines two operating modes, namely in-trap lift operation and mirror operation, is presented and characterized for the present setup. For ion capture in-trap lift switching was employed and exit-side mirror switching for ejection with higher information content. Measurements were performed with small lead clusters to illustrate individual advantages of both techniques and the gain of combining them with focus on the ions’ ToF ejection window.
In the second part, a recently introduced method of ion separation by transversal ejection of unwanted species inside the trap was studied for the present setup. The ejection is performed by appropriate pulses of the potentials of deflector electrodes located in the trap. The various parameters affecting the selection effectivity and resolving power are illustrated with tin-cluster measurements, with resolving powers of up to several tens of thousands.
The third part presents the experiment in detail, with the construction of each component and measurements for its various performance parameters. Because the heart of the setup is the MR-ToF analyzer the characterization focuses on the trap. In addition, cluster ions were mass selected in the MR-ToF device and photodissociated. The charged fragments were stored and mass analyzed in a proof-of principle MS/MS experiment where both MS steps were performed in the MR-ToF operation mode.
For a long time the apocryphal Ladder of Jacob was accessible only in arbitrarily selected translations. Without a critical edition and a comprehensive study of the whole textual segment, scholars were unable to evaluate its significance for Early Jewish and Christian literature. Since 2015/17, with the publication of a new critical edition and German translation (accompanied by a detailed introduction, footnote commentaries and appendices with related texts), a new approach to this important but hitherto widely unknown text has been made possible. This approach verifies the different layers or strata in the text, which are: a supposed Jewish apocalypse (mid-second century), a Christian expansion of the angels speech in light of the praeparatio evangelica tradition (fourth–seventh centuries), a Jewish mystical prayer (eleventh century) and the incorporation of this narrative block into the Tolkovaja Paleja together with a series of exegetical commentaries (end of the thirteenth century). In the light of the new approach, it can be said that the Ladder of Jacob is most of all an outstanding example of mutual relations between Jewish and Christian theology.
Hyperoxia is a well-known cause of cerebral white matter injury in preterm infants with male sex being an independent and critical risk factor for poor neurodevelopmental outcome. We investigated the underlying mechanisms behind such a sex dependent difference in oligodendrocyte progenitor cells (OPCs). Our findings demonstrate that oxidative stress severely affects cellular functions related to energy metabolism, stress response, and maturation in male derived oligodendrocyte progenitor cells (OPCs) whereas the female cells remain largely unaffected. This impairment of maturation is accompanied by the downregulation of nucleoporin and nuclear lamina proteins. We identify Nup133, which regulates OPC maturation as a major target protein affected by hyperoxia in male cells and that this differential response is mediated by an inverse Nup133 regulation in the male and female cells. It also regulates mitochondrial function and oxidative stress response through its downstream target Nuclear respiratory factor 1 (Nrf1). Additionally, the presence of 17-β estradiol and higher amounts of fetal zone steroids (precursors for maternal estrogen synthesis during fetal development) confer resistance to the female cells mediated by the estrogen receptor alpha (ERα) along with Nup133. Both Nup133 and ERα regulate mitochondrial function and oxidative stress response by transcriptional regulation of Nrf1. These findings establish prominent sex based differences and the molecular mechanisms involved in differential response of OPCs towards oxidative stress and the important role of Nup133 in mediating a severe negative outcome in the male cells.
Microbial cell factories have been largely exploited for the controlled production of recombinant proteins, including industrial enzymes and biopharmaceuticals. The advent of high-throughput ‘-omics’ techniques have boosted the design of these production systems due to their valuable contribution to the field of systems metabolic engineering, a discipline integrating metabolic engineering with systems and synthetic biology. In order to thrive, the field of systems metabolic engineering needs absolute proteomics data to be generated, as proteins are the central players in the complex metabolic and adaptational networks. Due to advent of mass spectrometry-based proteomics, a substantial amount of absolute proteomic data became available in the past decade. However, membrane proteins remained inaccessible to these efforts.
Nonetheless, comparative studies targeting the membrane proteome have been quite successful in characterizing physiological processes. Hence, label-free proteomics was used in a study (Quesada-Ganuza et al, 2019 – Article I) to identify and optimize PrsA in Bacillus subtilis, for improved yield of amylase. Amylase is one of the most relevant enzymes in the biotechnological sector. By employing a label-free mass spectrometry approach targeting the membrane proteome of this bacterium, relative changes in heterologous and native levels of PrsA could be quantified. The results of this study evidenced that each PrsA shows different relative abundancies, but with no relevant impact in the yield of amylase.
Even though relative protein quantification can already provide a good visualization of the physiological changes occurring between different conditions, they are not sufficient to understand how resources are allocated in the cell under certain physiological conditions. Therefore, a global method for absolute membrane protein quantification remains the biggest requirement for systems metabolic engineering.
Hence, with this work, we successfully developed a mass spectrometry-based approach enabling the absolute quantification of membrane proteins (Antelo-Varela et al, 2019 – Article II). This study was also performed in the Gram-positive model organism Bacillus subtilis, regarded as a prolific microbial cell factory. The method developed in this work combines the comprehensiveness of shotgun proteomics with the sensitivity and accuracy of targeted mass spectrometry. Fundamental to the method is that it relies on the application of a correction and an enrichment factor to calibrate absolute membrane protein abundances derived from shotgun mass spectrometry. This has permitted, for the first time reported, the calculation of absolute membrane protein abundances in a living organism.
The newly developed approach enabled to accurately quantify ~40% of the predicted proteome of this bacterium, offering a clear visualization of the physiological rearrangements occurring upon the onset of osmotic stress. In addition, this work also provides evidence for new membrane protein stoichiometries.
Overall, this study enabled the development of a straightforward methodology long-needed in the scientific and biotechnological community and, for the first time reported, providing absolute abundances of one of the most puzzling fractions of the cell – the membrane proteome.
The next step of the work summarized here was to implement the afore described method to a biotechnological relevant strain, as absolute membrane protein abundances are essential to understand the fundamental principles of protein secretion and production stress. Hence, this work was applied in a genome-reduced B. subtilis strain, ‘midiBacillus’, expressing the major staphylococcal antigen IsaA (Antelo-Varela et al, submitted – Article III). The employed absolute membrane protein quantification methodology enabled the analysis of physiological rearrangements occurring upon the induction of heterologous protein production. This work showed that, even though IsaA was successfully secreted into the growth medium, one of the main requirements for the biotechnological sector, it was still partly accumulated in the cell membrane of this bacterium. This led to an exacerbated physiological response where membrane proteins involved in the management of secretion stress were activated. In addition, this study also showed that a rearrangement of the cell’s translocation machinery occurs upon induction of production, where a ‘game’ of in- and decrease of transporters takes place.
Anticipating the impact of genetic and environmental insults, such as the ones caused by production stress, is essential for the field of systems metabolic engineering. Thus, the highly accurate and comprehensive dataset generated during this work can be implemented in predictive mathematical models, thereby contributing in the rational design of next-generation secretion systems.
In phylogenetics, evolutionary relationships of different species are represented by phylogenetic trees.
In this thesis, we are mainly concerned with the reconstruction of ancestral sequences and the accuracy of this reconstruction given a rooted binary phylogenetic tree.
For example, we wish to estimate the DNA sequences of the ancestors given the observed DNA sequences of today living species.
In particular, we are interested in reconstructing the DNA sequence of the last common ancestor of all species under consideration. Note that this last common ancestor corresponds to the root of the tree.
There exist various methods for the reconstruction of ancestral sequences.
A widely used principle for ancestral sequence reconstruction is the principle of parsimony (Maximum Parsimony).
This principle means that the simplest explanation it the best.
Applied to the reconstruction of ancestral sequences this means that a sequence which requires the fewest evolutionary changes along the tree is reconstructed.
Thus, the number of changes is minimized, which explains the name of Maximum Parsimony.
Instead of estimating a whole DNA sequence, Maximum Parsimony considers each position in the sequence separately. Thus in the following, each sequence position is regarded separately, and we call a single position in a sequence state.
It can happen that the state of the last common ancestor is reconstructed unambiguously, for example as A. On the other hand, Maximum Parsimony might be indecisive between two DNA nucleotides, say for example A and C.
In this case, the last common ancestor will be reconstructed as {A,C}.
Therefore we consider, after an introduction and some preliminary definitions, the following question in Section 3: how many present-day species need to be in a certain state, for example A, such that the Maximum Parsimony estimate of the last common ancestor is also {A}?
The answer of this question depends on the tree topology as well as on the number of different states.
In Section 4, we provide a sufficient condition for Maximum Parsimony to recover the ancestral state at the root correctly from the observed states at the leaves.
The so-called reconstruction accuracy for the reconstruction of ancestral states is introduced in Section 5. The reconstruction accuracy is the probability that the true root state is indeed reconstructed and always takes two processes into account: on the one hand the approach to reconstruct ancestral states, and on the other hand the way how the states evolve along the edges of the tree. The latter is given by an evolutionary model.
In the present thesis, we focus on a simple symmetric model, the Neyman model.
The symmetry of the model means for example that a change from A to C is equally likely than a change from C to A.
Intuitively, one could expect that the reconstruction accuracy it the highest when all present-day species are taken into account. However, it has long been known that the reconstruction accuracy improves when some taxa are disregarded for the estimation.
Therefore, the question if there exits at least a lower bound for the reconstruction accuracy arises, i.e. if it is best to consider all today living species instead of just one for the reconstruction.
This is bad news for Maximum Parsimony as a criterion for ancestral state reconstruction, and therefore the question if there exists at least a lower bound for the reconstruction accuracy arises.
In Section 5, we start with considering ultrametric trees, which are trees where the expected number of substitutions from the root to each leaf is the same.
For such trees, we investigate a lower bound for the reconstruction accuracy, when the number of different states at the leaves of the tree is 3 or 4.
Subsequently in Section 6, in order to generalize this result, we introduce a new method for ancestral state reconstruction: the coin-toss method.
We obtain new results for the reconstruction accuracy of Maximum Parsimony by relating Maximum Parsimony to the coin-toss method.
Some of these results do not require the underlying tree to be ultrametric.
Then, in Section 7 we investigate the influence of specific tree topologies on the reconstruction accuracy of Maximum Parsimony. In particular, we consider balanced and imbalanced trees as the balance of a tree may have an influence on the reconstruction accuracy.
We end by introducing the Colless index in Section 8, an index which measures the degree of balance a rooted binary tree can have, and analyze its extremal properties.
Spinal cord injury (SCI) above mid-thoracic levels leads to autonomic dysfunction affecting both the cardiovascular system and thermoregulation. The renin-angiotensin system (RAS) which is a potent regulator of blood pressure, including its novel beneficial arm with the receptor Mas could be an interesting target in post-SCI hemodynamics. To test the hypothesis that hemodynamics, activity and diurnal patterns of those are more affected in the Mas deficient mice post-SCI we used a mouse model of SCI with complete transection of spinal cord at thoracic level 4 (T4-Tx) and performed telemetric monitoring of blood pressure (BP) and heart rate (HR). Our data revealed that hypothermia deteriorated physiological BP and HR control. Preserving normothermia by keeping mice at 30°C prevented severe hypotension and bradycardia post-SCI. Moreover, it facilitated rapid return of diurnal regulation of BP, HR and activity in wild type (WT) mice. In contrast, although Mas deficient mice had comparable reacquisition of diurnal HR rhythm, they showed delayed recovery of diurnal rhythmicity in BP and significantly lower nocturnal activity. Exposing mice with T4-Tx (kept in temperature-controlled cages) to 23°C room temperature for one hour at different time-points post-SCI, demonstrated their inability to maintain core body temperature, Mas deficient mice being significantly more impaired than WT littermates. We conclude that Mas deficient mice were more resistant to acute hypotension, delayed nocturnal recovery, lower activity and more severely impaired thermoregulation. The ambient temperature had significant effect on hemodynamics and, thus it should be taken into account when assessing cardiovascular parameters post-SCI in mice.
Summary
The susceptibility of Candida albicans biofilms to a non‐thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods, the C. albicans strain SC5314 was treated with a microwave‐induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a 40 s plasma treatment time were observed for C. albicans. After such a treatment, the biofilms revealed an altered morphology of their cells by atomic force microscopy (AFM). Additionally, fluorescence microscopy and confocal laser scanning microscopy (CLSM) analyses of plasma‐treated biofilms showed that an inactivation of cells mainly appeared on the bottom side of the biofilms. Thus, the plasma inactivation of the overgrown surface reveals a new possibility to combat biofilms.
Introduction: Hearing and vision loss are highly prevalent in elderly adults, and thus frequently occur in conjunction with cognitive impairments. Studies have shown that hearing impairment is associated with a higher risk of dementia. However, evidence concerning the association between vision loss and dementia, as well as the co-occurrence of vision and hearing loss and dementia, has been inconclusive.
Objectives: To assess the association between: (i) either hearing or vision loss and the risk of dementia, as well as between; and (ii) the combination of both sensory impairments and the risk of dementia.
Methods: This case-control study was based on a 5-year data set that included patients aged 65 years and older who had initially been diagnosed with dementia diseases by one of 1,203 general practitioners in Germany between January 2013 and December 2017. In total, 61,354 identified dementia cases were matched to non-dementia controls, resulting in a sample size of 122,708 individuals. Hearing loss and vision loss were identified using the ICD-10 diagnoses documented in the general practitioners’ files prior to the initial dementia diagnosis. Multivariate logistic regression models were fitted to evaluate the associations between visual and/or hearing impairment and the risk of dementia and controlled for sociodemographic and clinical variables.
Results: Hearing impairment was documented in 11.2% of patients with a dementia diagnosis and 9.5% of patients without such a diagnosis. Some form of vision impairment was documented in 28.4% of patients diagnosed with dementia and 28.8% of controls. Visual impairment was not significantly associated with dementia (OR = 0.97, CI = 95% 0.97–1.02, p = 0.219). However, patients with hearing impairment were at a significantly higher risk of developing dementia (OR = 1.26, CI = 95% 1.15–1.38, p < 0.001), a finding that very likely led to the observed significant association of the combination of both visual and hearing impairments and the risk of dementia (OR = 1.14, CI = 95% 1.04–1.24, p = 0.005).
Discussion: This analysis adds important evidence that contributes to the limited body of knowledge about the association between hearing and/or vision loss and dementia. It further demonstrates that, of the two, only hearing impairment affects patients’ cognition and thus contributes to dementia risk.
Brain aging even in healthy older adults is characterized by a decline in cognitive functions including memory, learning and attention. Among others, memory is one of the major cognitive functions affected by aging. Understanding the mechanisms underlying age-related memory decline may help pave the road for novel treatment strategies. Here, we tried to elucidate the neural correlates associated with memory decline using structural and functional neuroimaging and neuromodulation with transcranial direct current stimulation (tDCS).
Over the course of three studies, we investigated 1) the influence of white matter integrity and grey matter volume on memory performance in healthy older adults, 2) the role of functional coupling within the memory network in predicting memory performance and the impact of tDCS in modulating retrieval performance in healthy older adults, 3) the effect of tDCS over the sensorimotor cortex on cognitive performance in young adults.
MRI was used to study associations of cognitive performance with white matter integrity and grey matter volume, and examine their causal relationship in the course of aging. White matter integrity was assessed by acquiring diffusion tensor imaging (DTI) and performing deterministic tractography based on constrained spherical deconvolution. Grey matter volume was estimated using fully automated segmentation. Both white matter integrity and grey matter volume were correlated with behavioral data of a verbal episodic memory task. Percentage of correct answers at retrieval was used to measure memory performance (Manuscript 1). In addition, anodal tDCS (atDCS) (1 mA, 20 min) was applied over CP5 (left temporoparietal cortex) to modulate memory formation in healthy older adults. Participants underwent resting-state fMRI before the stimulation. Functional connectivity analysis was performed to determine whether functional coupling within the memory network predicted initial memory performance, and to examine its association to tDCS-induced enhancement effect (Manuscript 2). Finally, atDCS (1 mA, 20 min) was applied over C3 (left sensorimotor cortex) to explore the effect of tDCS over the sensorimotor cortex on cognitive performance in young adults. During the stimulation, participants performed three tasks; gestural task, attentional load task and simple reaction time task (Manuscript 3).
Results showed that volumes of the left dentate gyrus (DG) and tractography-based fractional anisotropy (FA) of individual fornix pathways were positively related to memory retrieval in older adults. Brain-behavior associations were observed for correct rejections rather than hits of memory performance, indicating specificity of memory network functioning for detecting false associations. Thus, the data suggested a particular role of neural integrity that promotes successful memory retrieval in older adults. Subsequent mediation analysis showed that left DG volume mediated the effect of fornix FA on memory performance (48%), corrected for age, revealing a crucial role of hippocampal pathway microstructure in modulating memory performance in older adults (Manuscript 1). tDCS results showed that atDCS led to better retrieval performance and increasing learning curves, indicating that brain stimulation can induce plasticity of episodic memory processes in older adults. Combining tDCS and fMRI, hippocampo-temporoparietal functional connectivity was positively associated with initial memory performance in healthy older adults and was positively correlated with the magnitude of individual tDCS-induced enhancement, suggesting that individual tDCS responsiveness may be determined by intrinsic network coupling (Manuscript 2). Finally, our findings suggested that atDCS over left sensorimotor cortex reduced reaction times in the gestural-verbal integration task, specifically for incongruent pairs of gestures and verbal expressions, indicating the role of sensorimotor cortex in gestural-verbal integration in young adults (Manuscript 3).
The results of all three studies may help to elucidate age-related structural deterioration and functional coupling network underlying cognitive processes in healthy adults. Furthermore, these studies emphasized the importance of interventions like tDCS in modulating cognitive performance, specifically episodic verbal memory and gestural-verbal integration. By unveiling the specific role of brain structures and functional network coupling as well as the role of tDCS in modulating cognitive performance, our results contribute to a better understanding of brain-behavior associations, and may help to develop clinical interventional approaches, tailored for specific cognitive functions in aging.
In this thesis, we elaborate upon Bayesian changepoint analysis, whereby our focus is on three big topics: approximate sampling via MCMC, exact inference and uncertainty quantification. Besides, modeling matters are discussed in an ongoing fashion. Our findings are underpinned through several changepoint examples with a focus on a well-log drilling data.
Staphylococcus aureus is one of the commonly encountered bacteria of the human microbiome. Although mostly a seemingly harmless commensal microbe, S. aureus can act as an invasive pathogen with seriously devastating effects on its host’s health and wellbeing. A wide range of infections caused by this bacterium has been reported to affect diverse parts of the human body, including the skin, soft tissues and bones, as well as important organs like the heart, kidneys and lungs. Particularly, S. aureus is infamous for being a major causative agent of respiratory tract infections that may escalate up to necrotizing pneumonia. Due to its clinical relevance, this pathogen has been intensively studied for many years. Nonetheless, further research in this field is still needed, because of the high capacity of S. aureus to evolve drug resistance, its high genomic plasticity and adaptability and, not in the last place, the plethora of niches within the human body where it can thrive and survive. In this regard, there are still many uncertainties concerning the specific adaptations carried out by S. aureus during colonization and infection of the human body, the transition between both stages, and upon the invasion of different types of host cells. To shed more light on some of these adaptations, the research described in this thesis has employed in vitro models of infection that mimic particular conditions during the infectious process with special focus on the lung epithelium. The adaptations displayed by S. aureus were monitored using advanced proteomics. Furthermore, the analyses documented in this thesis included S. aureus strains with diverse backgrounds and epidemiology to take into account the genetic diversity encountered in this species.
Biocatalytic Production of Amino Carbohydrates through Oxidoreductase and Transaminase Cascades
(2019)
Plant-derived carbohydrates are an abundant renewable re- source. Transformation of carbohydrates into new products, in- cluding amine-functionalized building blocks for biomaterials applications, can lower reliance on fossil resources. Herein, bio- catalytic production routes to amino carbohydrates, including oligosaccharides, are demonstrated. In each case, two-step bio- catalysis was performed to functionalize d-galactose-contain- ing carbohydrates by employing the galactose oxidase from Fusarium graminearum or a pyranose dehydrogenase from
Agaricus bisporus followed by the w-transaminase from Chro- mobacterium violaceum (Cvi-w-TA). Formation of 6-amino-6- deoxy-d-galactose, 2-amino-2-deoxy-d-galactose, and 2-amino- 2-deoxy-6-aldo-d-galactose was confirmed by mass spectrome- try. The activity of Cvi-w-TA was highest towards 6-aldo-d-gal- actose, for which the highest yield of 6-amino-6-deoxy-d-galac- tose (67%) was achieved in reactions permitting simultaneous oxidation of d-galactose and transamination of the resulting 6- aldo-d-galactose.
Long-term nationally representative caries data in the primary dentition are rare, but nonetheless central to assess needs in caries prevention and treatment. This study evaluated the prevalence and trends of caries levels in the primary dentition of 6- to 7-year-olds in Germany as a whole and its federal states individually. In 2016, employing a randomized cluster selection, 6- to 7-year-old first graders were included in the National German Oral Health Survey performed regularly since 1994/95. Children were examined by 482 calibrated dentists in all 17 German regions using the WHO criteria for the decayed, missing, and filled teeth (dmft) including the assessment of initial carious lesions (it). In total, 151,555 6- to 7-year-olds were examined. Caries prevalence in the primary dentition dropped from 65% in 1994 to 44% in 2016, while the mean caries experience dropped from 2.89 to 1.73 dmft (dt = 0.74, mt = 0.19, ft = 0.80). When initial lesions were included, the mean caries experience increased to idmft = 2.12 (it = 0.38). In 2016, 49.7% of the examined 6- to 7-year-olds were caries-free including initial lesions. The Care Index at the tooth level was 57.5%, and the Significant Caries Index was 4.84 dmft. Depending on the German region, the mean dmft varied considerably, ranging from 1.37 to 2.31. In conclusion, despite the overall caries decline in 6- to 7-year-olds in Germany, only minor caries reductions were observed over the last decade, with a still existing high proportion of untreated dental decay. This calls for more effective preventive and restorative efforts with focus on the primary dentition in Germany.
Changes in Interhemispheric Motor Connectivity Across the Lifespan: A Combined TMS and DTI Study
(2019)
Age-related decline in interhemispheric connectivity between motor areas has been reported with both transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) measurements. However, not all studies were able to confirm these findings, and previous studies did not apply structural (DTI) and functional (TMS) measurements within each individual appropriately. Here, we investigated age dependency of the ipsilateral silent period (ISP) and integrity of fibers in the corpus callosum as operationalized by fractional anisotrophy (FA), using TMS and DTI, respectively, in 20 participants between 19 and 72 years of age. We found age-dependent increase for ISP, and decrease of FA, both indicating a decrease in interhemispheric inhibition, with a negative association between FA and ISP for the dominant hemisphere (r = −0.39, p = 0.043). Our findings suggest that aging leads to decline of interhemispheric motor connectivity, as evidenced in both structural and functional parameters, which should be taken into account when interpreting disease- or medication-related changes.
The aim of the present dissertation was to investigate the biological and chemical potential of two European mushroom species: Fomitopsis betulina and Calvatia gigantea. For this purpose, different extracts of both fungi were tested for: antimicrobial, antifungal, cytotoxic, in vitro wound healing, and anti-adhesive properties. Bioassay-guided fractionation led to the isolation of bioactive compounds, altogether 20 compounds were isolated and identified. The compounds were obtained from the ethyl acetate extracts, they included triterpenes, sterols and aromatic compounds. The separated substances from both fungi were proved for biological activities, some of them showed antimicrobial and cytotoxic activities.
Due to a variety of plasma sources in terms of type of discharge, energy yield, working gas or geometric factors, it is recommended to standardize the study protocol by choosing a plasma source and easy access to rugged tumor surfaces as demonstrated by the CAP-plasma-jet. The intention of the trial shall be to optimize the plasma jet for tumor site capability and operating room implementation.
It makes sense to start clinical trials in plasma medicine with the treatment of head and neck squamous cell carcinoma patients of infected wounds and ulcerations.
CAP is able to reduce contamination of cancer ulcerations and the typical fetid odor that often accompanies head and neck cancer patients. The intention of the trial shall be to evaluate the efficiency of decontamination in head and neck cancer ulcerations in terms of pathogenic species, amount of reduction and reliability.
Standardize study protocol:
Phase I, clinical explorative single-arm, randomized, open, multicenter
Primary objective
Reduction of microbial burden of cancer ulcerations by application of CAP
Secondary objective:
Reduction of tumor following local CAP application
Inclusion:
20 Patients suffering from locally advanced oral cavity carcinoma with open tumor surfaces, treated with palliative intention and no more curative treatment options
Exclusion:
No wish for treatment, no compliance and understanding the protocol of the clinical study
Efficacy:
reduction of microbial burden; Documentation of visible changes by photography; Pathohistological and biochemical examination of specimen, taken from the tumor area and control areas
Procedure:
Plasma is applied for 1 minute per cm², spot area of 3 mm diameter distance between nozzle and tumor surface of 14 mm. 3 times/week with a break of 1 week followed by a repeated cycle for another week.
Conclusion:
The most important intention of the trial from the clinician’s point of view shall be to make CAP-treatment an effective and well-accepted addition to standard cancer therapy based upon EBM at least in palliative medicine.
Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations.
Determining the effect of a changing climate on tree growth will ultimately depend on our understanding of wood formation processes and how they can be affected by environmental conditions. In this context, monitoring intra-annual radial growth with high temporal resolution through point dendrometers has often been used. Another widespread approach is the microcoring method to follow xylem and phloem formation at the cellular level. Although both register the same biological process (secondary growth), given the limitations of each method, each delivers specific insights that can be combined to obtain a better picture of the process as a whole. To explore the potential of visualizing combined dendrometer and histological monitoring data and scrutinize intra-annual growth data on both dimensions (dendrometer → continuous; microcoring → discrete), we developed DevX (Dendrometer vs. Xylogenesis), a visualization application using the “Shiny” package in the R programming language. The interactive visualization allows the display of dendrometer curves and the overlay of commonly used growth model fits (Gompertz and Weibull) as well as the calculation of wood phenology estimates based on these fits (growth onset, growth cessation, and duration). Furthermore, the growth curves have interactive points to show the corresponding histological section, where the amount and development stage of the tissues at that particular time point can be observed. This allows to see the agreement of dendrometer derived phenology and the development status at the cellular level, and by this help disentangle shrinkage and swelling due to water uptake from actual radial growth. We present a case study with monitoring data for Acer pseudoplatanus L., Fagus sylvatica L., and Quercus robur L. trees growing in a mixed stand in northeastern Germany. The presented application is an example of the innovative and easy to access use of programming languages as basis for data visualization, and can be further used as a learning tool in the topic of wood formation and its ecology. Combining continuous dendrometer data with the discrete information from histological-sections provides a tool to identify active periods of wood formation from dendrometer series (calibrate) and explore monitoring datasets.
GPR68 (OGR1) belongs to the proton-sensing G protein-coupled receptors that are involved
in cellular adaptations to pH changes during tumour development. Although expression of GPR68
has been described in many tumour cell lines, little is known about its presence in human tumour
entities. We characterised the novel rabbit monoclonal anti-human GPR68 antibody 16H23L16
using various cell lines and tissue specimens. The antibody was then applied to a large series of
formalin-fixed, paraffin-embedded normal and neoplastic human tissue samples. Antibody specificity
was demonstrated in a Western blot analysis of GPR68-expressing cells using specific siRNAs.
Immunocytochemical experiments revealed pH-dependent changes in subcellular localisation of the
receptor and internalisation after stimulation with lorazepam. In normal tissue, GPR68 was present in
glucagon-producing islet cells, neuroendocrine cells of the intestinal tract, gastric glands, granulocytes,
macrophages, muscle layers of arteries and arterioles, and capillaries. GPR68 was also expressed
in neuroendocrine tumours, where it may be a positive prognostic factor, in pheochromocytomas,
cervical adenocarcinomas, and endometrial cancer, as well as in paragangliomas, medullary thyroid
carcinomas, gastrointestinal stromal tumours, and pancreatic adenocarcinomas. Often, tumour
capillaries were also strongly GPR68-positive. The novel antibody 16H23L16 will be a valuable tool for
basic research and for identifying GPR68-expressing tumours during histopathological examinations.
The aim of the present study was to construct a biological age score reflecting one’s physiologic capability and aging condition with respect to tooth loss over 10 y. From the follow-up to the population-based Study of Health in Pomerania (i.e., SHIP-2), 2,049 participants were studied for their baseline biomarker measures 10 y before (i.e., in SHIP-0). Metabolic and periodontal data were regressed onto chronological age to construct a score designated as “biological age.” For either sex separately, the impact of this individualized score was used to predict tooth loss in the follow-up cohort in comparison with each participant’s chronological age. Outcome data after 10 y with respect to tooth loss, periodontitis, obesity, and inflammation were shown to be better for biologically younger subjects than as expected by their chronological age, whereas for the older subjects, data were worse. Especially for tooth loss, a striking increase was observed in subjects whose biological age at baseline appeared to be higher than their chronological age. Biological age produced significantly better tooth loss predictions than chronological age (P < 0.001). Areas under receiver operating characteristic curves for tooth loss of ≥3 teeth in men during follow-up were 0.811 and 0.745 for biological and chronological age, respectively. For women, these figures were 0.788 and 0.724. For total tooth loss, areas under the curve were 0.890 and 0.749 in men and 0.872 and 0.752 in women. Biological age combines various measures into a single score and allows identifying individuals at increased risk of tooth loss.
The purpose of this study was to compare the effect of culture on consumers’ attitudes toward Cause-Related marketing between Iran and Germany by answering the following questions:
A: What is consumer’s response concerning (1) skepticism toward CRM claim (2) attitude toward the CRM strategy, (3) attitude toward CRM brand personality, (4) attitude toward the CRM brand image and (5) CRM purchase intention (6) Warm glow? ; B: Do consumers respond differently to Cause-Related Marketing in Iran in comparison to Germany? C: Can cultural characteristics of the countries explain these differences? To answer the research questions, hypotheses were developed based on the literature which shape the research framework, in total containing 17 hypotheses. The data was gathered by questionnaire to make the research quantitative. By using convenience sampling, 564 responses were generated. The data was analysed by Structural Equation Modeling (SEM) and independent student t-test. Potential differences between Iran and Germany as well as moderation analysis are tested by critical ratio difference test as well as chi-square difference test using multiple- group analysis in AMOS. The results showed the importance of culture in applying CRM strategy. It can be said that CRM in a collectivistic culture like Iran can be successful as well as individualistic country like Germany. Although Iranian consumers were less familiar with this strategy, the benefits of CRM were similar in case of brand image and higher for purchase intention. The research found that emotions play a stronger role in Iran and it is more critical to evoke proper emotions by CRM campaign.
A successful colonization of different compartments of the human host requires multifactorial contacts between bacterial surface proteins and host factors. Extracellular matrix proteins and matricellular proteins such as thrombospondin-1 play a pivotal role as adhesive substrates to ensure a strong interaction with pathobionts like the Gram-positive Streptococcus pneumoniae and Staphylococcus aureus. The human glycoprotein thrombospondin-1 is a component of the extracellular matrix and is highly abundant in the bloodstream during bacteremia. Human platelets secrete thrombospondin-1, which is then acquired by invading pathogens to facilitate colonization and immune evasion. Gram-positive bacteria express a broad spectrum of surface-exposed proteins, some of which also recognize thrombospondin-1. This review highlights the importance of thrombospondin-1 as an adhesion substrate to facilitate colonization, and we summarize the variety of thrombospondin-1-binding proteins of S. pneumoniae and S. aureus.
Type I interferonopathies cover a phenotypically heterogeneous group of rare genetic diseases including the recently described proteasome-associated autoinflammatory syndromes (PRAAS). By definition, PRAAS are caused by inherited and/or de novo loss-of-function mutations in genes encoding proteasome subunits such as PSMB8, PSMB9, PSMB7, PSMA3, or proteasome assembly factors including POMP and PSMG2, respectively. Disruption of any of these subunits results in perturbed intracellular protein homeostasis including accumulation of ubiquitinated proteins which is accompanied by a type I interferon (IFN) signature. The observation that, similarly to pathogens, proteasome dysfunctions are potent type I IFN inducers is quite unexpected and, up to now, the underlying molecular mechanisms of this process remain largely unknown. One promising candidate for triggering type I IFN under sterile conditions is the unfolded protein response (UPR) which is typically initiated in response to an accumulation of unfolded and/or misfolded proteins in the endoplasmic reticulum (ER) (also referred to as ER stress). The recent observation that the UPR is engaged in subjects carrying POMP mutations strongly suggests its possible implication in the cause-and- effect relationship between proteasome impairment and interferonopathy onset. The purpose of this present review is therefore to discuss the possible role of the UPR in the pathogenesis of PRAAS. We will particularly focus on pathways initiated by the four ER-membrane proteins ATF6, PERK, IRE1-a, and TCF11/Nrf1 which undergo activation under proteasome inhibition. An overview of the current understanding of the mechanisms and potential cross-talk between the UPR and inflammatory signaling casacades is provided to convey a more integrated picture of the pathophysiology of PRAAS and shed light on potential biomarkers and therapeutic targets.
Type I interferonopathies cover a phenotypically heterogeneous group of rare genetic diseases including the recently described proteasome-associated autoinflammatory syndromes (PRAAS). By definition, PRAAS are caused by inherited and/or de novo loss-of-function mutations in genes encoding proteasome subunits such as PSMB8, PSMB9, PSMB7, PSMA3, or proteasome assembly factors including POMP and PSMG2, respectively. Disruption of any of these subunits results in perturbed intracellular protein homeostasis including accumulation of ubiquitinated proteins which is accompanied by a type I interferon (IFN) signature. The observation that, similarly to pathogens, proteasome dysfunctions are potent type I IFN inducers is quite unexpected and, up to now, the underlying molecular mechanisms of this process remain largely unknown. One promising candidate for triggering type I IFN under sterile conditions is the unfolded protein response (UPR) which is typically initiated in response to an accumulation of unfolded and/or misfolded proteins in the endoplasmic reticulum (ER) (also referred to as ER stress). The recent observation that the UPR is engaged in subjects carrying POMP mutations strongly suggests its possible implication in the cause-and-effect relationship between proteasome impairment and interferonopathy onset. The purpose of this present review is therefore to discuss the possible role of the UPR in the pathogenesis of PRAAS. We will particularly focus on pathways initiated by the four ER-membrane proteins ATF6, PERK, IRE1-α, and TCF11/Nrf1 which undergo activation under proteasome inhibition. An overview of the current understanding of the mechanisms and potential cross-talk between the UPR and inflammatory signaling casacades is provided to convey a more integrated picture of the pathophysiology of PRAAS and shed light on potential biomarkers and therapeutic targets.
For decades, evolutionary biologists have sought to understand the evolution of individual behaviour, physiology and ecology allowing organisms to cope to environmental change. One of the main challenges of current climate change is the unprecedent rate of temperature increase, as well as the increased occurence of extreme heat events. Interindividual response variability opens a whole new area of opportunities to understand how individual phenotypic traits are linked to individual response differences. In colour polymorphic species, colour honestly reflects an individual’s life-history strategy, and each morph may, therefore, represent an alternative life-history strategy. As such, colour polymorphic species, such as the Gouldian finch (Erythrura gouldiae), may be good models to assess how different strategies between morphs are linked to their espective responses to environmental variations. However, polymorphic species have mainly been disregarded for that purpose. In this context, the main aim of this thesis was to understand how the two morphs of the Gouldian finch respond through phenotypic plasticity to simulated heatwaves reaching thermocritical temperatures, and whether such differential responses may help to identify a ‘winner’ and a ‘loser’ morph in the light of climate change. To address these issues, we used an integrative approach including measurements of behavioural (Study 1), physiological (Study 2), and reproductive (Study 3) parameters. The novelty of our approach was to assess the immediate behavioural and physiological response variation of individuals of the two morphs longitudinally across different thermal conditions, as well as the postponed effects of this thermocritical heatwave exposure on their reproductive performance. In this study, although the behavioural responses generally did not differ between morphs or according to temperature intensity, the physiological and reproductive parameters differed in response to morph and temperature intensity. Blackheaded females, in particular, seem highly sensitive to thermocritical heatwaves, as they exhibited decreased body mass and increased oxidative damage during the thermocritical heatwaves, and advanced breeding initiation after these conditions, whereas these variables remained mostly unaffected in black-headed males and red-headed individuals. However, despite some response differences between morphs, both invested similarly in reproduction following intense heatwaves, and the offspring of both morphs were similarly affected. Based on these results, no morph therefore seems to appear more disadvantaged than the other following an intense heatwave, and red- and black-headed Gouldian finches may both be considered as climate stress ‘losers’.
Extracts from the leaves and flowers of Crataegus spp. (i.e., hawthorn species) have been traditionally used with documented preclinical and clinical activities in cardiovascular medicine. Based on reported positive effects on heart muscle after ischemic injury and the overall cardioprotective profile, the present study addressed potential contributions of Crataegus extracts to cardiopoietic differentiation from stem cells. The quantified Crataegus extract WS®1442 stimulated cardiomyogenesis from murine and human embryonic stem cells (ESCs). Mechanistically, this effect was found to be induced by promoting differentiation of cardiovascular progenitor cell populations but not by proliferation. Bioassay-guided fractionation, phytochemical and analytical profiling suggested high-molecular weight ingredients as the active principle with at least part of the activity due to oligomeric procyanidines (OPCs) with a degree of polymerization between 3 and 6 (DP3–6). Transcriptome profiling in mESCs suggested two main, plausible mechanisms: These were early, stress-associated cellular events along with the modulation of distinct developmental pathways, including the upregulation of brain-derived neurotrophic factor (BDNF) and retinoic acid as well as the inhibition of transforming growth factor β/bone morphogenetic protein (TGFβ/BMP) and fibroblast growth factor (FGF) signaling. In addition, WS®1442 stimulated angiogenesis ex vivo in Sca-1+ progenitor cells from adult mice hearts. These in vitro data provide evidence for a differentiation promoting activity of WS®1442 on distinct cardiovascular stem/progenitor cells that could be valuable for therapeutic heart regeneration after myocardial infarction. However, the in vivo relevance of this new pharmacological activity of Crataegus spp. remains to be investigated and active ingredients from bioactive fractions will have to be further characterized.
Deciphering the influence of Streptococcus pneumoniae global regulators on fitness and virulence
(2019)
Streptococcus pneumoniae (S. pneumoniae; the pneumococcus) is a Gram-positive, aerotolerant, and opportunistic bacteria, which colonizes the upper respiratory tract of human. S. pneumoniae can further migrate to other sterile parts of the body, and causes local as well as fatal infections like, pneumonia, septicaemia and meningitis. Due to incomplete amino acid pathways, pneumococci are auxotrophic for eight different amino acids including glutamine and arginine. The pneumococcus has adapted to the various host environmental conditions and a number of systems are dedicated for the transport and utilization of nutrients such as monosaccharides, amino acids and oligopeptides.
In this study the amino acid metabolism was characterised by 15N-isotopologue profiling in two different pneumococcal strains, D39 and TIGR4. Efficient uptake of a labelled amino acids mixture of 15N-labelled amino acids showed that S. pneumoniae has a preference for the amino acids transport instead of a de novo biosynthesis. It is known that glutamine (Gln) serves as main nitrogen source for S. pneumoniae. The 15N-labelled Gln used in this study demonstrated an efficient 15N-enrichment of Glu, Ala, Pro and Thr. Minor enrichment was seen for the amino acids Asp, Ile, Leu, Phe, Tyr, and Val. Remarkably, labelled Gly and Ser could be determined in strain TIGR4, whereas for strain D39 these two labelled amino acids were not detected. This confirms earlier studies with 13C-labelled glucose, which showed the biosynthesis of Ser out of Gly. Strain TIGR4 was able to grow in chemically-defined medium depleted of Gly confirming that Gly can be synthesized out of serine by the action of the enzyme serine hydroxymethyltransferase (SHMT).
The transcriptional regulator GlnR controls the Gln and Glu metabolism in S. pneumoniae. Hence, the impact of the repressor GlnR on amino acids metabolism was also studied. An increased 15N-enrichment was determined for Ala and Glu in both used pneumococcal strains, while an increased level of Pro was only measured in the isogenic glnR-mutant of non-encapsulated D39.
Arginine can also serve as nitrogen source in strain TIGR4. The arginine deiminase system metabolizes Arg into ornithine, carbamoyl phosphate and CO2 by the generation of 1 ATP and 2 mol NH3. Because of the truncation of the arcA gene strain D39 lacks arginine deiminase activity and has thus no functional ADS system. When 15N-Arg was added for growth, only in strain TIGR4, thirteen (13) labelled amino acids were detected with the highest enrichment for Ala, Glu and Thr. Genes coding for the enzymes of the arginine metabolism and for arginine uptake are regulated by the activator ArgR2 in strain TIGR4. Inactivation of ArgR2 was not accompanied by an enrichment of labelled amino acids, when the argR2-mutant was grown with 15N-labelled Arg indicative of the important role of ArgR2.
The bicistronic operon arcDT encoding the arginine/ornithine transporter ArcD and a putative peptidase ArcT belong to the peptidase family M20. The in silico comparison of structures revealed a significant homology of ArcT to PepV of L. delbrueckii and to Sapep of S. aureus known as carboxypeptidase. ArcT was heterologously expressed in E. coli and purified under reducing conditions. An enzymatic reaction was established and several dipeptides like Ala-Arg, Arg-Ala, and Ala-Asp were used as substrates. In addition, the dependency on divalent cations was analysed. Cleavage of the dipeptide Ala-Arg was detected in the presence of Mn2+ as cofactor under reducing conditions. Reduced peptidase activity was observed when Zn2+ was added. No cleavage of the tripeptide Ala-Ala-Arg could be shown indicating that ArcT acts as dipeptidase with the preference to the Arg residue at the C-terminal end.
Bacterial meningitis caused by S. pneumoniae was studied in an in vivo proteomic analysis. In a mouse meningitis model S. pneumoniae was isolated from the cerebrospinal fluid (CSF) by a filter extraction step. The MS analysis identified AliB and ComDE only from CSF isolated pneumococci indicating that these proteins are expressed under infection conditions. Mice infected with D39 wild-type and isogenic aliB, comDE and aliB-comDE double knockout mutants showed significantly less number of pleocytosis in the CSF and lower bacterial load in the blood compared to the wild-type. The results indicate that AliB and ComDE play an important role during meningitis.
Phenotypic characterization was carried out to identify differences between the wild-type and the aliB-, comDE- and aliB-comDE double mutants. Oxidative stress conditions were induced by the application of hydrogen peroxide or paraquat during growth in a chemically-defined medium similar to the CSF. No alteration in growth and survival of these mutants compared to the wild-type was observed suggesting that oxygen radicals play not an important role during the progression of meningitis. In addition, no differences of AliB expression was detected in the ComDE deficient D39. No impact of aliB and comDE-mutation on the expression of different virulence factors like pneumolysin or proteins involved in capsular biosynthesis was detected.
In vitro proteome analysis was performed to compare the wild-type to the AliB, and ComDE deficient D39 in the early and mid logarithmic growth phase. More than 70 % of theoretically expressed proteins were identified. In the aliB-mutant 33 proteins were differentally expressed in the early growth phase and 50 proteins differed during mid log growth. For the comDE mutant 24 and 11 proteins differed in expression in these two growth phases. Interestingly, high level of AliA expression was identified in all samples. The aliB-mutant had a decreased abundance of the proteins resembling an oligopeptide ABC transporter (AmiA, AmiC, AmiD, AmiE). In addition, another ABC transporter for iron transport encoded by spd_1607 to spd_ 1610 was higher expressed in the aliB-mutant. In the ComDE deficient mutant lower abundance of the Ami transporter sytem was identified. An increased abundance of proteins involved in the pyrimidine metabolism (PyrF, PyrE, PyrDb, PyrB and PyrR) was recognized only in the early growth phase of the comDE-mutant. These analyses demonstrate the marginal changes in protein synthesis during growth of S. pneumoniae. These studies demonstrated the adaptation of the proteome of S. pneumoniae to different growth conditions and the impact of regulatory proteins on the availability of carbon and nitrogen sources.
Matrix-product-state based methods, in particular the density-matrix renormalization group, are used to numerically investigate several one-dimensional systems, focusing on models with symmetry-protected topological phases that generalize the spin-1 Haldane chain. In the first part, ground state properties such as topological order parameters and the criticality at quantum phase transitions are studied.
The second part deals with dynamic properties of spin chains. Using time-dependent matrix-product-state calculations, the dynamic structure factor, and the transport properties of contacted spin chains are analyzed.