Refine
Year of publication
- 2012 (59) (remove)
Document Type
- Doctoral Thesis (38)
- Article (21)
Language
- English (59) (remove)
Has Fulltext
- yes (59)
Is part of the Bibliography
- no (59)
Keywords
- - (21)
- Proteomanalyse (3)
- Atmosphärendruckplasma (2)
- Communication abilities (2)
- Gene expression (2)
- Kaltes Plasma (2)
- Phylogenie (2)
- Streptococcus pneumoniae (2)
- oxidative stress (2)
- 2-Phenoxyethanol (1)
Institute
- Institut für Physik (7)
- Institut für Mikrobiologie - Abteilung für Genetik & Biochemie (5)
- Abteilung für Mikrobiologie und Molekularbiologie (4)
- Institut für Chemie und Biochemie (4)
- Institut für Mathematik und Informatik (3)
- Institut für Geographie und Geologie (2)
- Institut für Hygiene und Umweltmedizin (2)
- Institut für Med. Biochemie u. Molekularbiologie (2)
- Institut für Pharmazie (2)
- Institut für Psychologie (2)
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung (UMG) (2)
- Klinik für Anästhesiologie und Intensivmedizin (2)
- Poliklinik für Kieferorthopädie, Präventive Zahnmedizin und Kinderzahnheilkunde (2)
- Zoologisches Institut und Museum (2)
- Friedrich-Loeffler-Institut für Medizinische Mikrobiologie (1)
- Historisches Institut (1)
- Institut für Anglistik/Amerikanistik (1)
- Institut für Botanik und Landschaftsökologie & Botanischer Garten (1)
- Institut für Community Medicine (1)
- Institut für Epidemiologie u. Sozialmedizin (1)
- Institut für Humangenetik (1)
- Institut für Pathologie (1)
- Institut für Pharmakologie (1)
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung (MNF) (1)
- Klinik für Psychiatrie und Psychotherapie (1)
- Klinik und Poliklinik für Augenheilkunde (1)
- Klinik und Poliklinik für Chirurgie (1)
- Klinik und Poliklinik für Chirurgie Abt. für Unfall- und Wiederherstellungschirurgie (1)
- Klinik und Poliklinik für Hals-, Nasen-, Ohrenkrankheiten (1)
- Klinik und Poliklinik für Neurologie (1)
- Poliklinik für Zahnerhaltung, Parodontologie und Endodontologie (1)
- Universitätsmedizin (1)
Publisher
The human brain is distinguished by its remarkable size, high energy consumption, and cognitive abilities compared to all other mammals and non-human primates. However, little is known about what has accelerated brain evolution in the human lineage. One possible explanation is that the appearance of advanced communication skills and language has been a driving force of human brain development. The phenotypic adaptations in brain structure and function which occurred on the way to modern humans may be associated with specific molecular signatures in today’s human genome and/or transcriptome. Genes that have been linked to language, reading, and/or autism spectrum disorders are prime candidates when searching for genes for human-specific communication abilities. The database and genome-wide expression analyses we present here revealed a clustering of such communication-associated genes (COAG) on human chromosomes X and 7, in particular chromosome 7q31-q36. Compared to the rest of the genome, we found a high number of COAG to be differentially expressed in the cortices of humans and non-human primates (chimpanzee, baboon, and/or marmoset). The role of X-linked genes for the development of human-specific cognitive abilities is well known. We now propose that chromosome 7q31-q36 also represents a hot spot for the evolution of human-specific communication abilities. Selective pressure on the T cell receptor beta locus on chromosome 7q34, which plays a pivotal role in the immune system, could have led to rapid dissemination of positive gene variants in hitchhiking COAG.
A molecular approach to characterize the arbuscular mycorrhizal fungus, Glomus sp. AMykor isolate
(2012)
The arbuscular mycorrhizal fungi (AMF) interaction with plants has a major impact on the soil ecosystem. However, so far, only a few studies on AMF genetics have been performed and molecular information on the genetic diversity of AMF is limited. In this study a fundamental genetic characterization of the industrial isolate, Glomus sp. AMykor (AMykor GmbH, Bitterfeld, Germany) has been undertaken to increase the understanding of AMF genetic diversity. Based on phylogenetic analysis of partial rDNA sequences, Glomus sp. AMykor isolate was proposed to belong to the G. irregulare species together with the reference isolate, DAOM197198. To investigate if both isolates differ in their ploidy level, fluorescence in situ hybridization (FISH) was performed and mainly one or two hybridization signals per nucleus were observed in both isolates. It is suggested that they harbour at least two major rDNA sites and possibly two minor sites. The DNA content was estimated by means of flow cytometry (FC) and confirmed by Feulgen densitometry (FD). The calculated average DNA content per nucleus is 153.0 ± 3.6 Mb for the G. irregulare AMykor isolate and 154.8 ± 6.2 Mb for the DAOM197198 isolate. Since there are plenty criticisms coming recently of using rDNA sequence for fungal barcoding there is necessity of development other system for the identification to species level of Glomeromycotan fungi. The focus of this part of the study was the GiFRD gene encoding fumarate reductase enzyme for use as a potential candidate for AMP species determination. Unfortunately, observed sequence variations do not allow the discrimination of Glomeromycotan species. However, further analysis of enzyme encoded by GiFRD showed a possible role of fumarate reductase in AMF redox balance maintaining under oxygen deficient conditions. Using a yeast expression system, it has been demonstrated that the protein encoded by GiFRD has fumarate reductase activity. The functional expression of GiFRD in the S. cerevisiae fumarate reductase deletion mutant restored the ability of growth under anaerobiosis which indicated that Gifrdp is able to functionally complement the S. cerevisiae missing genes. The fact that GiFRD expression was present only in the asymbiotic stage confirmed existence of at least one metabolic pathway involved in anaerobic metabolism and suggested that AMF behave as a facultative anaerobe in asymbiotic stage.
Despite a plethora of therapeutic approaches, the injection of local anaesthetics itself remains one of the most painful and dreadful procedures among children. Stimulation of acupoint LI4 is associated with analgesic effects in dentistry. Goal of the study To investigate whether stimulation of LI4, added to standard therapy (ST), reduces pain and distress during injection of local anaesthetic (LA) in comparison with ST alone. Materials and Methods Children, scheduled for dental treatment in local anaesthesia on 2 separate days were enrolled in this trial, approved by local ethics commission. On one day each child received bilateral acupuncture of LI4 point, using indwelling fixed “New Pyonex” needles (0.2 x 1.5 mm; Seirin, Japan). The parents of the children were asked to stimulate the needles by massage. Standardized injection of LA was performed 5 min following acupuncture. The needles were withdrawn at the end of dental treatment. On the other day of treatment children received LA injection without acupuncture. The order of treatment days (acupuncture first or vice versa) was randomised. Primary endpoint was the pain intensity during LA injection reported by children on Visual Rating Scale from 0=no pain to 10=maximal pain imaginable (VRS-11). Secondary endpoints were parent- and dentist-assessed pain intensity (measured on Numeric Rating Scale 1-10), patients’ heart rate before and during dental treatment and satisfaction with received therapy (measured on Numerical Rating Scale 1-5.) Side effects of LI4 stimulation were also recorded. Results and Discussion The data of 49 children (22 females; age 10 ± 4 yrs; mean ± SD), who completed both visits, were analysed. Children reported less pain with than without acupuncture: 2.2 ± 2.5 vs. 3.9 ± 2.7; mean ± SD, p<0.001. Heart rate decreased after LI4 stimulation compared to ST alone throughout the dental treatment (p<0.05). LI4 stimulation was safe and raised better satisfaction with the treatment among children and parents, than ST alone (p<0.05). Other secondary endpoints were comparable between both sessions. Conclusion Stimulation of acupuncture point LI4 reduces pain and autonomous stress during injection of local anaesthetics in paediatric dentistry.
The widespread use of natural and synthetic estrogens or chemicals with estrogenic activities is causing an increasing accumulation of estrogenic compounds in the environment. Already at very low concentrations these estrogenics can severely affect the wildlife, particularly in an aquatic environment. For these reasons measuring devices for detecting estrogen contaminations are in great demand. The majority of the analytical methods and bioassays on the market so far, lack semi-online adaptability, and usually cannot be used for automatic and continuous determination. Therefore, we have embarked on the development of new systems, which are able to fulfil those demands. The EstraMonitor combines recombinant A. adeninivorans G1212/YRC102-hERa-phyK yeast cells as the microbial component with an amperometric detection method to analyze estrogenic contaminations. A. adeninivorans G1212/YRC102-hERa-phyK was constructed by Kaiser et al. (2010). These cells were engineered to co-express the human estrogen receptor (hERa) gene and the inducible phytase (phyK, derived from Klebsiella sp. ASR1) reporter gene under control of a promoter with estrogen response elements (EREs). In the presence of estrogenic substances, such as 17ß -estradiol (E2), the phyK gene is expressed and recombinant phytase is secreted into the media. The level of phytase is quantified by amperometric detection using substrate p-aminophenyl phosphate (p-APP). Phytase dephosphorylates p-aminophenyl phosphate (p-APP) into an intermediate product p-aminophenol (p-AP). p-AP is electroactive and oxidized at the electrode. This generates electrons and produces a current which is proportional to the level of phytase activity. Since phytase activity is directly correlated to the E2 concentration, the estrogenic activity can thus be calculated from the current measured. The microbial component of the EstraMonitor, the non-immobilized A. adeninivorans G1212/YRC102-hERa-phyK, works well with the amperometric method in a quantitative manner. The optimal applied potential determined for amperometric measurements was 150 mV and provided a low background signal for the amperometric detection. The half maximal effective concentration (EC50) and limit of detection (LoD) values for E2 obtained from amperometric measurements with the EstraMonitor were 69.9 ng L-1 and 44.5 ng L-1, respectively. The measuring procedure of the EstraMonitor system including incubation of A. adeninivorans G1212/YRC102-hERa-phyK cells with E2, subsequently incubation with electrochemical substrate (p-APP), and signal recordation is completed within only 4 h and 10 min. Out of this total time, amperometric detection including substrate incubation and signals recordation takes only 10 min out of total time. The use of immobilized cells for a microbial biosensor is an essential advantage of the EstraMonitor system because it allows easy-handiness next to long-term stability and reusability. Immobilized A. adeninivorans G1212/YRC102-hERa-phyK cells revealed excellent properties which make them very suitable for semi-online, automatic and continuous monitoring. They were stable up to 30 days when stored at 4 °C. Furthermore, they could be reused up to 15 times. The EC50 and LoD values achieved for E2 using immobilized cells in combination with amperometric detection were 20.9 and 8.3 ng L-1, respectively. Furthermore, this application also removes the need to separate cells by centrifugation, to sterilize the samples as well as to cultivate repeatly. Additionally, both immobilized and non-immobilized A. adeninivorans G1212/YRC102-hERa-phyK cells remain fully functional in a wide range of untreated wastewater samples and in environments containing up to 5% NaCl. To enhance the sensitivity and reduce the time for estrogenic determination, an alternative A. adeninivorans G1214/YRC103-hERa-phyK strain was developed. This strain can produce a detectable amount of phytase within 2 h after induction with E2. It offers an improved microbial component in terms of sensitivity and time-effectiveness. In addition, to reduce the cost for estrogenic detection an alternative substrate, ascorbic acid 2-phosphate (AA2P), was tested. AA2P, which is both cheap and widely available, performed better than p-APP. The EC50 and LoD values for E2 obtained with AA2P were 15.69 and 0.92 ng L-1 versus 20.09 and 8.3 ng L-1 when examined with p-APP, respectively. Taken together, the EstraMonitor is an automated system with respect to sample cycling, sample measuring and calibration supplemented with an alarm function. This system makes it possible to control estrogenic activity semi-online, automatically and continuously. These are advantages of the EstraMonitor compared to other estrogenic detection systems. It can thus be concluded that, the EstraMonitor is a powerful and feasible semi-online device for monitoring estrogenic activity especially adapted for the use in sewage treatment plants.
In the framework of the current work has been the plasma initiated and surface catalysed species conversion studied in low pressure and atmospheric plasmas. The aim of the work is to improve the understanding of the internal processes in order to increase the energy efficiency as well as the selectivity of the reaction products of future plasma devices. Beside many technical applications of plasmas, air purification shows great potential. Over the last decades, plasma based pollution control has proofed its ability to remove harmful contaminants or annoying odours from an air stream. However, the energy efficiency and the selectivity of the products are a remaining challenge.
Motivated by these issues, a multi stage packed-bed reactor has been used to remove admixed ethylene and toluene from an air stream. It has been found that the maximum toluene destruction has been 60%, whereas ethylene has been nearly completely removed. The specific energy β has been between 120 and 1600 JL-1. Fourier Transform Infrared spectroscopy, FTIR spectroscopy, has been used to identify and quantify the species H2O, CO2, CO, O3, HNO3, HCN, CH2O, CH2O2, N2O and NO2. However, none of these experiments led to the detection of NO.
The embedment of packing material into a plasma volume leads to increased surface effects. In order to study them, the inner side of a tube reactor, made of Pyrex, served as the surface under study and has been exposed to a rf plasma for 1h. The surface effects of the plasma treatment have been investigated indirectly by studying the oxidation of NO into NO2. After the plasma exposure, the reactor has been evacuated and filled with a gas mixture of 1% NO in N2 / Ar. Both species have been measured using quantum cascade laser absorption spectroscopy, QCLAS. It has been found that, using oxygen containing plasmas, the NO concentration decreased whereas the NO2 concentration increased. Therefore, oxygen containing plasmas are able to deposit oxygen on the surface. The filling with NO leads to the oxidation via the Eley-Rideal mechanism. A simplified model calculation supports these assumptions.
For a more comfortable application of the QCLAS, a compact multi channel spectrometer has been developed, TRIPLE Q. It combines the high time resolution with the possibility to measure the concentration of at least three infrared active species simultaneously. Due to the high time resolution, a huge number of spectra have to be analysed. In order to calculate absolute number densities, an algorithm has been developed which automatically treats typical phenomena like pulse jitter, rapid passage effect or variations of the intensity of the laser pulses.
The gas temperature is an important parameter in plasma physics. Using the TRIPLE Q system, the gas temperature has been determined for pulsed dc plasmas. For this case, NO has been used as a probe gas. From the spectra, the temperature has been calculated using the line ratio method. The relative intensity of the absorption structures of NO at 1900.5cm-1 and 1900.08cm-1 depend on the temperature. Therefore, the ratio has been used to calculate the gas temperature with a time resolution in the μs range.
Vibrationally excited nitrogen can be an energy reservoir that plays an important role in plasma chemistry. In N2 / N2O plasmas, vibrationally excited N2 can undergo relaxation via a resonant vibration vibration coupling between vibrationally excited N2 and N2O. Due to such an efficient energy transfer, the method allows one to study the relaxation of vibrationally excited N2. Using this method, molecules, which are not infrared active, can be monitored. This approach has extended the field of scientific and commercial applications of the QCLAS.
Chronic infections, including periodontal infections, may reduce lung function. To date, there are hardly any population-based studies evaluating the association between periodontitis and lung function. However, there are some studies that used variables associated with obstructive pulmonary diseases (FEV1, FEV1/FVC). Thus, we aimed to assess the potential association of periodontal diseases with lung volumes and airflow limitation in the population-based Study of Health in Pomerania (SHIP). Of 3300 participants aged 25-85 years of the 5-year follow-up (SHIP-1), 1809 subjects participated in lung function examinations. 1465 subjects were included in the analyses. Lung function was measured using spirometry, body plethysmography, helium dilution, and diffusing capacity for carbon monoxide. Periodontal status was assessed by clinical attachment loss, probing depth, and number of missing teeth. Linear regression models using fractional polynomials were used to assess linear and non-linear associations between periodontal disease and lung function adjusting for confounders. Adjusting for age, sex, waist circumference, physical activity, diabetes, asthma, and time between core and pulmonary examination, mean attachment loss was significantly associated with variables of dynamic and static lung volumes, airflow limitation and hyperinflation. Total lung capacity and diffusing capacity for carbon monoxide were not associated with mean attachment loss. Adjustment for smoking and height considerably changed coefficients indicating profound confounding. Including fibrinogen and high sensitive CRP into fully adjusted models did not change coefficients of mean attachment loss. Restricted to never smokers, mean attachment loss was significantly associated with FEV1, FVC, and RV/TLC. Relations with lung function were confirmed for mean probing depth, extent measures of attachment loss/probing depth, and number of missing teeth. Periodontal disease was significantly associated with decreased lung function. Systemic inflammation did not provide a mechanism linking both diseases. However, cohort studies evaluating lung function in the current manner are needed to confirm results from this study and to assess a causal relationship. Furthermore, it needs to be investigated with the help of randomized clinical trials whether prevention or treatment of periodontitis might have a beneficial impact on lung function.
Abstract Atmospheric Pressure Discharges have attracted much interest in recent years. The development of a new processes based on this discharge needs a clear understanding of plasma and discharge physics and chemistry. At the present time much attention is paid to the chemical processes in barrier discharge plasma in various gas mixtures, since the understanding of these processes is necessary for the development of industrial reactors. Besides these, hydrocarbons are being used for the formation of diamond like or amorphous carbon (DLC) films. Specially, hydrogenated amorphous carbon (a-C: H) and plasma polymerization. In this work we have used Dielectric Barrier Discharge (DBD) a plasma device used to investigate simple hydrocarbon reactions in a plasma phase. Our aim of plasma phase chemical reaction studies is to form molecular hydrogen, higher order hydrocarbons CnHm up to n ≥ 12 series and nitrogen - containing organic complexes using simple hydrocarbons. Deposition of thin organic films or DLC films were carried out using the DBD. In this study we have chosen certain combination of gases such as C2Hm/N2 (m = 2, 4, 6) and C2Hm/Ar (m = 2, 4, 6); the purpose of using N2 and Ar gases are to dilute and stabilize the hydrocarbon plasma and to investigate plasma chemical reactions with nitrogen gas. All reactions were carried out under an atmospheric pressure (300 mbar) with gas ratio 1:2; Experiments were performed by applying high voltage with a frequency 5.5 kHz. The plasma phase diagnostics have been investigated using mass spectrometry and FTIR spectroscopy. Formation of molecular hydrogen, N-containing organic complexes and higher order hydrocarbons with C ≥ 12, have been investigated with mass spectrometry. FTIR spectroscopy reveals the formation of substituted alkanes (sp3), alkenes (sp2) and alkynes (sp) and nitrogen containing functional groups from the individual gases which are used in this work. Abundant formation of acetylene occurs with C2H6 and C2H4 as precursor gases. Amorphous hydrogenated carbon nitride (a-CNx:H) films have been deposited on Si (100) and glass substrates using gas mixtures C2Hm/N2 (m = 2, 4, 6). Surface chemical compositions have been derived from Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) and X-ray Photo electron Spectroscopy (XPS). FT-IRRAS and XPS show the presence of sp, sp2 and sp3 bonds of carbon and nitrogen for C2Hm/N2 thin films. Various functional groups such as amines, saturated and unsaturated alkyl groups have been identified. Thin films obtained from C2H2/N2 and C2H4/N2 gas mixture had a larger N/C ratio when compared to the film obtained from C2H6/N2. Thickness, refractive index and extinction co-efficient were investigated by ellipsometry. Rate of deposition have been investigated. Different surface morphology has been derived using Scanning Electron Microscopy. Amorphous hydrogenated carbon (a-C:H) films or diamond like carbon (DLC) films have been deposited on Si (100) and glass substrates using gas mixtures C2Hm/Ar (m = 2, 4, 6). Diagnostics for the deposited films have been done using different spectroscopic techniques. Surface chemical compositions have been derived from Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) and X-ray Photo electron Spectroscopy (XPS). FT-IRRAS show the presence of sp, sp2 and sp3 bonds of carbon and hydrogen for C2Hm/Ar (m = 2, 4, 6) thin films. The characteristic peak for C1s has been observed from XPS. Thickness, refractive index and extinction co-efficient were investigated by ellipsometry. Rate of deposition have been investigated.
In this thesis, all three BVMOs from Pseudomonas putida NCIMB10007, that were known to be responsible for the ability of this strain to degrade camphor since the 1950s were successfully made available as recombinant biocatalysts. While the genomic sequence of 2,5-DKCMO was available from the database, the genes encoding 3,6-DKCMO and OTEMO had to be identified using certain PCR-techniques first. All three enzymes were cloned into standard plasmids enabling convenient expression in E. coli facilitating the application of the enzymes in organic chemistry. Their synthetic potential was already reported during the 1990s, but at that time their efficient application was limited due to difficulties with respect to low production levels and insufficient purity and separation of enzyme fractions. These drawbacks are now overcome. Furthermore, biochemical characterization of the camphor-degrading BVMOs was performed including the substrate spectra of these enzymes. Thereby OTEMO turned out not only to have a broad substrate scope accepting mono- and bicyclic aliphatic and arylaliphatic ketones, but also to efficiently convert alpha/beta-unsaturated cycloalkanones due to the similarity of these compounds to OTEMOs natural substrate. Finally, the major limitation in the synthetic application of Type II BVMOs was addressed by searching a flavin-reductase suitable for coupling to these two-component oxygenases. Putative candidates from the respective P. putida strain were identified by the use of amino acid motifs conserved in other representatives of two-component systems. While these enzymes failed, flavin-reductase Fre from E. coli - that also contained the motifs - was shown to enhance the activity of the DKCMOs when applied as crude cell extract as well as pure enzyme. This finding represents a key step for future application of Type II BVMOs.
The worldwide distribution and prevalence of melioidosis, an infectious disease caused by the soil-dwelling Gram-negative bacterium Burkholderia pseudomallei, is unknown. In Vietnam, sporadic cases of melioidosis have been reported for decades, but clinical and epidemiological data for the indigenous population are still scarce. In this study, we reviewed clinical and demographic data of patients with culture-proven melioidosis diagnosed at a single large referral hospital in Hanoi between November 1997 and December 2005. The clinical manifestations of melioidosis with fatal septicaemia as the most common presentation, a high rate of underlying diseases and a peak of cases admitted during the wet season were similar to studies from other endemic areas. The geographical origin of melioidosis patients shows that melioidosis exists in at least 18 northern provinces. The characterization of clinical B. pseudomallei strains by multilocus sequence typing identified 17 different sequence types (STs), ten of which have (as yet) not been found outside Vietnam. Several of these STs presumably were generated through recent evolutionary events in this rapidly diversifying bacterial species, and thus restricted geographic distribution may be a consequence of limited time passed since emergence. In order to define the distribution of the bacterium in the environment, our study also aimed to develop a more sensitive culture method for the detection of B. pseudomallei from soil samples in endemic areas compared to the currently used culture method based on soil dispersion in water. Our newly developed protocol involving soil dispersion in a polyethylene glycol and sodium deoxycholate solution increased the yield of viable B. pseudomallei from soil samples. Comparative testing of soil samples from Northeast Thailand covering a wide range of B. pseudomallei concentrations demonstrated a significantly higher recovery (p < 0.0001) of B. pseudomallei colony forming units by the new method compared to the conventional method. Our data indicate that using the detergents polyethylene glycol and sodium deoxycholate not only results in a higher recovery of viable B. pseudomallei, but also results in a shift in the bacterial species recovered from soil samples. Molecular methods based on direct bacterial nucleic acid extraction from environmental samples and subsequent amplification have the potential to overcome many restrictions of traditional microbiological approaches. Moreover, culture-dependent methods require special expertise in recognizing B. pseudomallei colony morphologies. Thus, a highly sensitive culture-independent DNA-based method that allows direct quantification of B. pseudomallei from soil is needed, particularly in diagnostic laboratories outside endemic areas. We therefore aimed to establish a protocol for B. pseudomallei soil DNA isolation, purification and quantification by qPCR targeting a type three secretion system 1 single copy gene. This assay was validated using 40 soil samples from Northeast Thailand that underwent parallel bacteriological culture. All 26 samples that were B. pseudomallei-positive by direct culture were B. pseudomallei qPCR-positive, with a median of 1.84 x 104 genome equivalents (range 3.65 x 102 to 7.85 x 105) per gram of soil. This was 10.6 fold (geometric mean; range 1.1 to 151.3) higher than the bacterial count as defined by culture. Moreover, the qPCR detected B. pseudomallei in seven samples (median 36.9 genome equivalents per g soil; range 9.4 to 47.3), which were negative on direct culture. These seven positives were reproduced using a nested PCR targeting a second, independent B. pseudomallei-specific sequence. Two samples were direct culture and qPCR negative but nested PCR positive. Five samples were negative by both PCR methods and culture. In conclusion, this is the first report on a series of cases describing clinical and epidemiological features of melioidosis and corresponding Burkholderia pseudomallei strains from northern Vietnam. Moreover, our newly developed culture-based and PCR-based methods provide highly specific and sensitive tools for the quantitative environmental surveillance of B. pseudomallei.
Abstract
In the 21st century, most of the world’s glaciers are expected to retreat due to further global warming. The range of this predicted retreat varies widely as a result of uncertainties in climate and glacier models. To calibrate and validate glacier models, past records of glacier mass balance are necessary, which often only span several decades. Long-term reconstructions of glacier mass balance could increase the precision of glacier models by providing the required calibration data. Here we show the possibility of applying shrub growth increments as an on-site proxy for glacier summer mass balance, exemplified by Salix shrubs in Finse, Norway. We further discuss the challenges which this method needs to meet and address the high potential of shrub growth increments for reconstructing glacier summer mass balance in remote areas.
Background: In clinical practice, treatment of genital tract infections is based on administration of either antibiotics or antiseptics. While antibiotics may be applied systemically or topically, antiseptics may be applied only topically. In case of bacterial vaginosis (BV), antibiotic therapy may often be limited and side effects due to systemic administration may develop. Polihexanide (PHMB) is a promising option for the topical treatment of genital tract infections, in particular BV and vaginitis. Method: A systematic search for publications on the use of PHMB for the treatment of genital infections in two electronic databases was performed. Titles, abstracts and citations were imported into a reference database. Duplicates were removed and two reviewers assessed each identified publication separately. Results: Among a total of 204 references, 3 prospective randomized trials were identified. Two trials treated BV infections with PHMB in comparison to clindamycin as antibiotic standard therapy with no significant differences either in safety or in efficacy. The third controlled trial investigated the clinical efficacy of PHMB compared to placebo in the treatment of human papilloma virus. Patients treated with PHMB daily for up to 16-weeks showed significantly higher (52%) clearance of genital warts as compared to patients treated with placebo (4%). Conclusion: PHMB may be a clinically effective alternative for the treatment of BV and human papilloma virus. Although PHMB-based antiseptics are available since the late 90s, controlled trials to investigate its clinical potential for antiseptic treatment are scant. Clinical use of antiseptics for the treatment of infectious diseases should be explored and supported further.
The goal of this doctoral thesis is to create and to implement methods for fully automatic segmentation applications in magnetic resonance images and datasets. The work introduces into technical and physical backgrounds of magnetic resonance imaging (MRI) and summarizes essential segmentation challenges in MRI data including technical malfunctions and ill-posedness of inverse segmentation problems. Theoretical background knowledge of all the used methods that are adapted and extended to combine them for problem-specific segmentation applications are explained in more detail. The first application for the implemented solutions in this work deals with two-dimensional tissue segmentation of atherosclerotic plaques in cardiological MRI data. The main part of segmentation solutions is designed for fully automatic liver and kidney parenchyma segmentation in three-dimensional MRI datasets to ensure computer-assisted organ volumetry in epidemiological studies. The results for every application are listed, described and discussed before important conclusions are drawn. Among several applied methods, the level set method is the main focus of this work and is used as central segmentation concept in the most applications. Thus, its possibilities and limitations for MRI data segmentation are analyzed. The level set method is extended by several new ideas to overcome possible limitations and it is combined as important part of modularized frameworks. Additionally, a new approach for probability map generation is presented in this thesis, which reduces data dimensionality of multiple MR-weightings and incorporates organ position probabilities in a probabilistic framework. It is shown, that essential organ features (i.e. MR-intensity distributions, locations) can be well represented in the calculated probability maps. Since MRI data are produced by using multiple MR- weightings, the used dimensionality reduction technique is very helpful to generate a single probability map, which can be used for further segmentation steps in a modularized framework.
Colonization and infection of wounds represent a major reason for the impairment of tissue repair. Recently, it has been reported that tissue-tolerable plasma (TTP) is highly efficient in the reduction of the bacterial load of the skin. In the present study, the antiseptic efficacy of TTP was compared to that of octenidine hydrochloride with 2-phenoxyethanol. Both antiseptic methods proved to be highly efficient. Cutaneous treatment of the skin with octenidine hydrochloride and 2-phenoxyethanol leads to a 99% elimination of the bacteria, and 74% elimination is achieved by TTP treatment. Technical challenges with an early prototype TTP device could be held responsible for the slightly reduced antiseptic properties of TTP, compared to a standard antiseptic solution, since the manual treatment of the skin surface with a small beam of the TTP device might have led to an incomplete coverage of the treated area.
This thesis will discuss the different fields of application of the two soft ionization techniques ESI and MALDI in microbial proteomics and their importance for a better understanding of bacteria physiology. The general development in the past 25 years coming from 2D-gel analysis and protein identification by peptide mass fingerprint analysis via MALDI-TOF to genome wide quantitative LC-ESI-MS experiments with fast and sensitive ESI instruments is exemplary shown for the Gram-positive bacterium Bacillus subtilis in article I. Even though 2D-PAGE in conjunction with MALDI-MS is still an important tool in proteomic research, the more recently established global quantitative LC-ESI-MS workflows gain more and more relevance as they overcome 2D-PAGE based protein restrictions and enable the acquisition of higher accurate protein quantities. In article II such a workflow was used to analyze the physiological adaptation of Staphylococcus aureus to vancomycin treatment on a global-scale. Also post-translational modifications of proteins, that are important for regulation of their activity and allow rapid adaption to changed environmental conditions, could be analyzed by LC-ESI-MS workflows using special enrichment strategies (article III and IV). Despite the mentioned discrimination and less accurate quantification of proteins, 2D-PAGE analyses are still advantageous when analyzing large-scale time series experiments. To gain highly time resolved data but also very accurate relative quantities on a global-scale, 2D-PAGE-MALDI-MS and LC-ESI-MS techniques have been combined to investigate dynamic proteome adaptations of B. subtilis during nutrition shift as part of a global systems biology approach (article V). Also absolute quantities of proteins are of high interest for systems biology, but are still challenging to obtain on large-scale as well as with sufficient accuracy. In article VI a method that again combined 2D-PAGE-MALDI-MS and LC-ESI-MS was introduced to gain absolute protein quantities on global-scale. Utilizing the complementarity of 2D-PAGE and LC-ESI-MS this new workflow enabled fast and cost efficient data acquisition on absolute scale. In article VII we described for the first time a global quantitative LC-MALDI-MS workflow. Cross validation with an LTQ Orbitrap proofed that LC-MALDI-MS is able to process complex samples and obtain highly reliable quantities. The comparative analysis of data gained with both instrument types revealed biases for certain biochemical properties of MALDI as well as ESI instruments, resulting in a general complementarity of both ionization techniques. Article I Becher, D., Büttner, K., Moche, M., Hessling, B., Hecker, M., 2011. From the genome sequence to the protein inventory of Bacillus subtilis. Proteomics 11, 2971–2980. Article II Hessling,B., Bonn,F., Herbst,F.-A., Rappen,G.-M., Bernhardt,J., Hecker,M. and Becher,D. Global proteome analysis of vancomycin stress in Staphylococcus aureus. Submitted to Mol. Cell Proteomics. Article III Elsholz, A.K.W., Turgay, K., Michalik, S., Hessling, B., Gronau, K., Oertel, D., Mäder, U., Bernhardt, J., Becher, D., Hecker, M., Gerth, U., 2012. Global impact of protein arginine phosphorylation on the physiology of Bacillus subtilis. Proc. Natl. Acad. Sci. U.S.A. 109, 7451–7456. Article IV Chi, B.K., Gronau, K., Mäder, U., Hessling, B., Becher, D., Antelmann, H., 2011. S-bacillithiolation protects against hypochlorite stress in Bacillus subtilis as revealed by transcriptomics and redox proteomics. Mol. Cell Proteomics 10, M111.009506. Article V Buescher,J.M., Liebermeister,W., Jules,M., Uhr,M., Muntel,J., Botella,E., Hessling,B., Kleijn,R.J., Le Chat,L., Lecointe,F., et al. (2012) Global network reorganization during dynamic adaptations of Bacillus subtilis metabolism. Science, 335, 1099–1103. Article VI Maass, S., Sievers, S., Zühlke, D., Kuzinski, J., Sappa, P.K., Muntel, J., Hessling, B., Bernhardt, J., Sietmann, R., Völker, U., Hecker, M., Becher, D., 2011. Efficient, global-scale quantification of absolute protein amounts by integration of targeted mass spectrometry and two-dimensional gel-based proteomics. Anal. Chem. 83, 2677–2684. Article VII Hessling,B., Büttner,K., Hecker,M. and Becher,D. Global relative quantification with LC-MALDI – cross-validation with LTQ-Orbitrap proves reliability and reveals complementary ionization preferences. Submitted to Mol. Cell Proteomics.
Abstract
We present experiments on the luminescence of excitons confined in a potential trap at milli-Kelvin bath temperatures under continuous-wave (cw) excitation. They reveal several distinct features like a kink in the dependence of the total integrated luminescence intensity on excitation laser power and a bimodal distribution of the spatially resolved luminescence. Furthermore, we discuss the present state of the theoretical description of Bose–Einstein condensation of excitons with respect to signatures of a condensate in the luminescence. The comparison of the experimental data with theoretical results with respect to the spatially resolved as well as the integrated luminescence intensity shows the necessity of taking into account a Bose–Einstein condensed excitonic phase in order to understand the behaviour of the trapped excitons.
Streptococcus pneumoniae (pneumococci) are Gram-positive cocci and commensals of the human upper respiratory tract. Pneumococcal pathogenesis requires adherence to host cells and dissemination through cellular barriers and to evade host defense mechanisms. The Pneumococcal surface protein C (PspC) is an important virulence factor which has a crucial role in pneumococcal adhesion to host cells and immune evasion by manipulating the host complement system. To elucidate the pneumococcal adherence and uptake mechanism via factor H glycosaminoglycans (dermatan sulfate and heparin) were employed as competitive inhibitors in infection experiments with epithelial cells or human polymorphonuclear leukocytes (PMNs). Glycosaminoglycans significantly inhibited the FH mediated pneumococcal adherence and subsequent invasion to host epithelial cells. Furthermore, the short consensus repeats of FH which promotes the adhesion of pneumococci to host cells were identified by blocking experiments with domain mapped antibodies for specific regions of FH. Moreover, this study indicates that FH acts as adhesion molecule via cellular receptors recognized as integrin CR3 on human PMNs. Binding of Factor H loaded pneumococci to integrins CR3 was assessed by flow cytometry. Pneumococci coated with Factor H showed a significantly increased association with PMNs. This interaction was blocked by anti-CR3 antibodies and Pra1. This project further aims to study mechanisms of pneumococcal endocytosis by host cells, their intracellular fate, and the pathogen induced host cell signal transduction cascades including the calcium signaling upon pneumococcal infection of host cells via the PspC-hpIgR interaction. To assess now the role of protein tyrosine kinases (PTKs) during pneumococcal infection via PspC, cell culture infections were performed in presence of pharmacological inhibitors of PTKs and MAPKs or by employing genetic interference techniques. Blocking the function of Src or ER1/2 and JNK and genetic-knock down of Src and FAK reduced significantly internalization of pneumococci. These data indicated the importance of a coordinated signaling between Src PTKs, ERK1/2, and JNK during PspC-pIgR-mediated uptake of pneumococci by host epithelial cells. The impact of host cells intracellular calcium concentrations on pneumococcal PspC-hpIgR mediated internalization was studied. Intracellular calcium measurement of epithelial cells performed in the presence of pneumococci suggested a calcium influx in host epithelial cells and importantly this calcium influx was PspC- hpIgR specific as pspC-deficient pneumococci were unable to mediate calcium mobilization in host cells. The increase in intracellular calcium [Ca2+]i was dependent on phospholipase C as pretreatment of cells with a phospholipase C-specific inhibitor abolished the increase in [Ca2+]i. Furthermore, role of host intracellular calcium concentrations during pneumococcal internalization was demonstrated by employing specific pharmacological inhibitors and calcium chelators in epithelial cell culture infection assays. The results revealed that elevated host cells calcium concentrations diminished pneumococcal internalization while lower calcium concentration in host epithelial cells promoted pneumococcal uptake. This study further demonstrates that dynamin, clathrin and caveolin play a key role during pneumococcal endocytosis into host cells via PspC-hpIgR. The use of specific pharmacological inhibitors or genetic interference approaches against dynamin, clathrin and caveolin in epithelial cell culture infection assays significantly blocked pneumococcal uptake. Furthermore, confocal microscopy revealed that pneumococci co-localize with clathrin. At later stages of the infection the pathogen is sorted to early, late and recycling endosomes as indicated by co-localization of pneumococci with endosomal markers such as Rab5, Rab4, Rab 7, and Lamp1. In order to get further insights into PspC-hpIgR mediated uptake mechanisms, a chimeric PspC was constructed and expressed heterologously on the surface of Lactococcus lactis. Immunofluorescence staining, immunoblot and flow cytometric analysis of L. lactis confirmed the expression of PspC on the bacterial surface. Moreover the ability of recombinant lactococci expressing PspC to adhere to and to invade pIgR-expressing epithelial cells confirmed the functional activity of PspC when exposed on the lactococcal surface. PspC expressing lactococci confirmed the specificity of PspC-hpIgR mediated endocytosis in host epithelial cells as PspC deficient lactococci were not taken up by these host cells. Confocal microscopic analysis demonstrated that only PspC expressing lactococci were sorted to early, late and recycling endosomes, similar to the intracellular fate of S. pneumoniae.
The learning theory of panic disorder differs between panic attacks and anxious apprehension as distinct emotional states. Acute panic is accompanied by extreme fear, experience of strong body symptoms reflecting autonomic surge and flight tendencies. In contrast, anxious apprehension is associated with hypervigilance towards bodily sensations and increased distress when subtle somatic symptoms are identified. Following animal models, these clinical entities reflect different stages of defensive reactivity depending upon the imminence of interoceptive or exteroceptive threat cues with lowest distance to threat during panic attacks. We tested this model by investigating the dynamics of defensive reactivity in a large group of patients suffering from panic disorder and agoraphobia (PD/AG) prior to a multicenter controlled clinical trial. Three hundred forty-five patients participated in a standardized behavioral avoidance test (being entrapped in a small, dark chamber for 10 minutes). Defensive reactivity was assessed measuring avoidance and escape behavior, self reports of anxiety and panic symptoms, autonomic arousal (heart rate and skin conductance), and potentiation of the startle reflex before and during the exposure period of the behavioral avoidance test. While 125 patients showed strong anxious apprehension during the task (as indexed by increased reports of anxiety, elevated physiological arousal, and startle potentiation), 72 patients escaped from the test chamber. Active escape was initiated at the peak of the autonomic surge accompanied by an inhibition of the startle response as predicted by the animal model. These physiological responses were observed during 34 reported panic attacks as well. We found evidence that defensive reactivity in PD/AG patients is dynamically organized ranging from anxious apprehension to panic with increasing proximity of interoceptive threat. Importantly, the patients differed quite substantially according defensive reactivity during the behavioral avoidance test despite all patients received the same principal diagnosis. These differences can be explained in part by differences in the disposition according to two genetic variants previously associated with panic disorder. Patients carrying the risk variant of a polymorphism in the neuropeptide S receptor gene showed an overall increased heart rate during the whole behavioral avoidance test reflecting an enhanced sympathomimetic activation and consequently arousal level. During the entrapment situation in which heart rate further increased over an already elevated baseline level, risk variant carriers were prone to experience more panic symptoms. This is in line with the learning perspective of panic disorder, postulating that internal cues of elevated arousal increase the chance of experiencing another panic attack once they have been associated with aversive responses. Furthermore, the risk variant of a polymorphism in the monoamine oxidase A gene was observed to augment the occurrence of panic attacks and escape behavior preparation. In addition, we find evidence that suggest an enhanced resistance to corrective learning experiences as indicated by a lack of a reduction of avoiding and escaping behavior during repeated test chamber exposures in wait-list control patients carrying the risk gene variant. Both effects may strengthen the learning mechanism hypothesized to be involved in the pathogenesis of panic disorder. Exteroceptive and interoceptive cues previously associated with the initial panic attack might trigger subsequent attacks in risk allele carriers more rapidly while simultaneously the opportunity to dissolve once established associations due to contradictory experiences is limited. Now, differential dispositions regarding defensive reactivity in PD/AG patients has to be linked to mechanisms supposed to be involved in exposure based therapy. First outcome evaluations of the clinical trial indicated that a behavioral therapy variant suggested to be linked with higher fear activation during exposure exercises is more effective than another. Further analyses have to proof whether those patients showing a clear specific fear response during the behavioral avoidance test benefit more than others from exposure based therapy.
Background: Controversy surrounds the questions whether co-occurring depression has negative effects on cognitivebehavioral therapy (CBT) outcomes in patients with panic disorder (PD) and agoraphobia (AG) and whether treatment for PD and AG (PD/AG) also reduces depressive symptomatology. Methods: Post-hoc analyses of randomized clinical trial data of 369 outpatients with primary PD/AG (DSM-IV-TR criteria) treated with a 12-session manualized CBT (n = 301) and a waitlist control group (n = 68). Patients with comorbid depression (DSM-IV-TR major depression, dysthymia, or both: 43.2% CBT, 42.7% controls) were compared to patients without depression regarding anxiety and depression outcomes (Clinical Global Impression Scale [CGI], Hamilton Anxiety Rating Scale [HAM-A], number of panic attacks, Mobility Inventory [MI], Panic and Agoraphobia Scale, Beck Depression Inventory) at post-treatment and follow-up (categorical). Further, the role of severity of depressive symptoms on anxiety/depression outcome measures was examined (dimensional). Results: Comorbid depression did not have a significant overall effect on anxiety outcomes at post-treatment and follow-up, except for slightly diminished post-treatment effect sizes for clinician-rated CGI (p = 0.03) and HAM-A (p = 0.008) when adjusting for baseline anxiety severity. In the dimensional model, higher baseline depression scores were associated with lower effect sizes at post-treatment (except for MI), but not at follow-up (except for HAM-A). Depressive symptoms improved irrespective of the presence of depression. Conclusions: Exposure-based CBT for primary PD/AG effectively reduces anxiety and depressive symptoms, irrespective of comorbid depression or depressive symptomatology.
Background: To analyze the relation and distribution of mean, systolic and diastolic ocular perfusion pressure (OPP) in telemedical homemonitoring of patients with primary open-angle glaucoma (POAG). Methods: 70 patients with POAG measured intraocular pressure (IOP) and blood pressure at home for a period of 6 months with the Goldmann applanation self-tonometer Ocuton S and the blood pressure device boso medicus PC. Twenty-four-hour profiles were taken every 4 weeks in addition to single measurements in the morning and evening once a week. All measured values were transmitted to an electronic patient record, which calculated OPP by taking systolic, diastolic and mean arterial blood pressure and subtracting IOP. Results: We analyzed 3,282 values of mean, systolic and diastolic OPP. The quantity of values below the risk levels of the Barbados Eye Studies was calculated. We found values lower than the risk levels for LE: 49 (1.5%)/RE: 60 (1.8%) systolic OPP, LE: 1,623 (49.5%)/RE: 1,761 (53.7%) diastolic OPP and LE: 687 (20.9%)/RE: 794 (24.2%) mean OPP. The individual average OPP levels of all 70 patients below the risk levels showed the following distribution: LE: 4 (5.7%)/RE: 6 (8.6%) systolic OPP, LE: 19 (27.1%)/RE: 20 (28.6%) diastolic OPP and LE: 10 (14.3%)/RE: 10 (14.3%) mean OPP. Conclusion: The individual distribution of different OPP values in POAG patients is not easy to interpret for clinical ophthalmologists. Precise practicable guidelines for clinical use still have to be determined.
In order to identify possible experimental signatures of the superfluid to Mott-insulator quantum phase transition we calculate the charge structure factor S(k, ω) for the one-dimensional Bose-Hubbard model using the dynamical density-matrix renormalisation group (DDMRG) technique. Particularly we analyse the behaviour of S(k, ω) by varying – at zero temperature–the Coulomb interaction strength within the first Mott lobe. For strong interactions, in the Mott-insulator phase, we demonstrate that the DDMRG results are well reproduced by a strong-coupling expansion, just as the quasi-particle dispersion. In the super-fluid phase we determine the linear excitation spectrum near k = 0. In one dimension, the amplitude mode is absent which mean-field theory suggests for higher dimensions.