Publications (13)49.9 Total impact
-
Article: Characterization and optimization of Bacillus subtilis ATCC 6051 as an expression host.
[show abstract] [hide abstract]
ABSTRACT: The genome sequence of Bacillus subtilis ATCC 6051 and its suitability as an expression host for recombinant protein production was determined. The comparison of this undomesticated wild type with the widely used laboratory strain B. subtilis 168 reveals a high degree of congruency between the two strains. Differences could only be detected on the level of point mutations or small insertions. B. subtilis ATCC 6051 shows none of the auxotrophies known for B. subtilis 168 and is able to produce polyketides. It exhibits better use of complex media and higher genomic stability through reduced natural competence. Consequently, B. subtilis ATCC 6051 was genetically modified to yield an optimized strain for the production of heterologously expressed proteins under control of an acetoin-inducible promoter.Journal of biotechnology 07/2012; · 2.88 Impact Factor -
Article: Involvement of two latex-clearing proteins during rubber degradation and insights into the subsequent degradation pathway revealed by the genome sequence of Gordonia polyisoprenivorans strain VH2.
[show abstract] [hide abstract]
ABSTRACT: The increasing production of synthetic and natural poly(cis-1,4-isoprene) rubber leads to huge challenges in waste management. Only a few bacteria are known to degrade rubber, and little is known about the mechanism of microbial rubber degradation. The genome of Gordonia polyisoprenivorans strain VH2, which is one of the most effective rubber-degrading bacteria, was sequenced and annotated to elucidate the degradation pathway and other features of this actinomycete. The genome consists of a circular chromosome of 5,669,805 bp and a circular plasmid of 174,494 bp with average GC contents of 67.0% and 65.7%, respectively. It contains 5,110 putative protein-coding sequences, including many candidate genes responsible for rubber degradation and other biotechnically relevant pathways. Furthermore, we detected two homologues of a latex-clearing protein, which is supposed to be a key enzyme in rubber degradation. The deletion of these two genes for the first time revealed clear evidence that latex-clearing protein is essential for the microbial utilization of rubber. Based on the genome sequence, we predict a pathway for the microbial degradation of rubber which is supported by previous and current data on transposon mutagenesis, deletion mutants, applied comparative genomics, and literature search.Applied and environmental microbiology 02/2012; 78(8):2874-87. · 3.69 Impact Factor -
Article: An ancient pathway combining carbon dioxide fixation with the generation and utilization of a sodium ion gradient for ATP synthesis.
[show abstract] [hide abstract]
ABSTRACT: Synthesis of acetate from carbon dioxide and molecular hydrogen is considered to be the first carbon assimilation pathway on earth. It combines carbon dioxide fixation into acetyl-CoA with the production of ATP via an energized cell membrane. How the pathway is coupled with the net synthesis of ATP has been an enigma. The anaerobic, acetogenic bacterium Acetobacterium woodii uses an ancient version of this pathway without cytochromes and quinones. It generates a sodium ion potential across the cell membrane by the sodium-motive ferredoxin:NAD oxidoreductase (Rnf). The genome sequence of A. woodii solves the enigma: it uncovers Rnf as the only ion-motive enzyme coupled to the pathway and unravels a metabolism designed to produce reduced ferredoxin and overcome energetic barriers by virtue of electron-bifurcating, soluble enzymes.PLoS ONE 01/2012; 7(3):e33439. · 4.09 Impact Factor -
Article: Proteomic analysis of the extremely thermoacidophilic archaeon Picrophilus torridus at pH and temperature values close to its growth limit.
[show abstract] [hide abstract]
ABSTRACT: The thermoacidophilic archaeon Picrophilus torridus belongs to the Thermoplasmatales order and is the most acidophilic organism known to date, growing under extremely acidic conditions around pH 0 (pH(opt) 1) and simultaneously at high temperatures up to 65°C. Some genome features that may be responsible for survival under these harsh conditions have been concluded from the analysis of its 1.55 megabase genome sequence. A proteomic map was generated for P. torridus cells grown to the mid-exponential phase. The soluble fraction of the cells was separated by isoelectric focusing in the pH ranges 4-7 and 3-10, followed by a two dimension (2D) on SDS-PAGE gels. A total of 717 Coomassie collodial-stained protein spots from both pH ranges (pH 4-7 and 3-10) were excised and subjected to LC-MS/MS, leading to the identification of 665 soluble protein spots. Most of the enzymes of the central carbon metabolism were identified on the 2D gels, corroborating biochemically the metabolic pathways predicted from the P. torridus genome sequence. The 2D master gels elaborated in this study represent useful tools for physiological studies of this thermoacidophilic organism. Based on quantitative 2D gel electrophoresis, a proteome study was performed to find pH- or temperature-dependent differences in the proteome composition under changing growth conditions. The proteome expression patterns at two different temperatures (50 and 70°C) and two different pH conditions (pH 0.5 and 1.8) were compared. Several proteins were up-regulated under most stress stimuli tested, pointing to general roles in coping with stress.Proteomics 12/2011; 11(23):4559-68. · 4.43 Impact Factor -
Article: Physiological homogeneity among the endosymbionts of Riftia pachyptila and Tevnia jerichonana revealed by proteogenomics.
[show abstract] [hide abstract]
ABSTRACT: The two closely related deep-sea tubeworms Riftia pachyptila and Tevnia jerichonana both rely exclusively on a single species of sulfide-oxidizing endosymbiotic bacteria for their nutrition. They do, however, thrive in markedly different geochemical conditions. A detailed proteogenomic comparison of the endosymbionts coupled with an in situ characterization of the geochemical environment was performed to investigate their roles and expression profiles in the two respective hosts. The metagenomes indicated that the endosymbionts are genotypically highly homogeneous. Gene sequences coding for enzymes of selected key metabolic functions were found to be 99.9% identical. On the proteomic level, the symbionts showed very consistent metabolic profiles, despite distinctly different geochemical conditions at the plume level of the respective hosts. Only a few minor variations were observed in the expression of symbiont enzymes involved in sulfur metabolism, carbon fixation and in the response to oxidative stress. Although these changes correspond to the prevailing environmental situation experienced by each host, our data strongly suggest that the two tubeworm species are able to effectively attenuate differences in habitat conditions, and thus to provide their symbionts with similar micro-environments.The ISME Journal 10/2011; 6(4):766-76. · 7.38 Impact Factor -
Article: Genome sequence of Brevibacillus laterosporus LMG 15441, a pathogen of invertebrates.
[show abstract] [hide abstract]
ABSTRACT: Here we announce the genome sequence of the bacterium Brevibacillus laterosporus LMG 15441, which is a pathogen of invertebrates. The genome consists of one chromosome and two circular plasmids. Sequence analysis revealed a large potential to produce polyketides, nonribosomal peptides, and toxins.Journal of bacteriology 10/2011; 193(19):5535-6. · 3.94 Impact Factor -
Article: Genome sequence analyses of two isolates from the recent Escherichia coli outbreak in Germany reveal the emergence of a new pathotype: Entero-Aggregative-Haemorrhagic Escherichia coli (EAHEC).
[show abstract] [hide abstract]
ABSTRACT: The genome sequences of two Escherichia coli O104:H4 strains derived from two different patients of the 2011 German E. coli outbreak were determined. The two analyzed strains were designated E. coli GOS1 and GOS2 (German outbreak strain). Both isolates comprise one chromosome of approximately 5.31 Mbp and two putative plasmids. Comparisons of the 5,217 (GOS1) and 5,224 (GOS2) predicted protein-encoding genes with various E. coli strains, and a multilocus sequence typing analysis revealed that the isolates were most similar to the entero-aggregative E. coli (EAEC) strain 55989. In addition, one of the putative plasmids of the outbreak strain is similar to pAA-type plasmids of EAEC strains, which contain aggregative adhesion fimbrial operons. The second putative plasmid harbors genes for extended-spectrum β-lactamases. This type of plasmid is widely distributed in pathogenic E. coli strains. A significant difference of the E. coli GOS1 and GOS2 genomes to those of EAEC strains is the presence of a prophage encoding the Shiga toxin, which is characteristic for enterohemorrhagic E. coli (EHEC) strains. The unique combination of genomic features of the German outbreak strain, containing characteristics from pathotypes EAEC and EHEC, suggested that it represents a new pathotype Entero-Aggregative-Haemorrhagic E scherichia c oli (EAHEC).Archives of Microbiology 06/2011; 193(12):883-91. · 1.43 Impact Factor -
Article: Status quo in physiological proteomics of the uncultured Riftia pachyptila endosymbiont.
[show abstract] [hide abstract]
ABSTRACT: Riftia pachyptila, the giant deep-sea tube worm, inhabits hydrothermal vents in the Eastern Pacific ocean. The worms are nourished by a dense population of chemoautotrophic bacterial endosymbionts. Using the energy derived from sulfide oxidation, the symbionts fix CO(2) and produce organic carbon, which provides the nutrition of the host. Although the endosymbionts have never been cultured, cultivation-independent techniques based on density gradient centrifugation and the sequencing of their (meta-) genome enabled a detailed physiological examination on the proteomic level. In this study, the Riftia symbionts' soluble proteome map was extended to a total of 493 identified proteins, which allowed for an explicit description of vital metabolic processes such as the energy-generating sulfide oxidation pathway or the Calvin cycle, which seems to involve a reversible pyrophosphate-dependent phosphofructokinase. Furthermore, the proteomic view supports the hypothesis that the symbiont uses nitrate as an alternative electron acceptor. Finally, the membrane-associated proteome of the Riftia symbiont was selectively enriched and analyzed. As a result, 275 additional proteins were identified, most of which have putative functions in electron transfer, transport processes, secretion, signal transduction and other cell surface-related functions. Integrating this information into complex pathway models a comprehensive survey of the symbiotic physiology was established.Proteomics 06/2011; 11(15):3106-17. · 4.43 Impact Factor -
Article: Pyrosequencing-based assessment of bacterial community structure along different management types in German forest and grassland soils.
[show abstract] [hide abstract]
ABSTRACT: Soil bacteria are important drivers for nearly all biogeochemical cycles in terrestrial ecosystems and participate in most nutrient transformations in soil. In contrast to the importance of soil bacteria for ecosystem functioning, we understand little how different management types affect the soil bacterial community composition. We used pyrosequencing-based analysis of the V2-V3 16S rRNA gene region to identify changes in bacterial diversity and community structure in nine forest and nine grassland soils from the Schwäbische Alb that covered six different management types. The dataset comprised 598,962 sequences that were affiliated to the domain Bacteria. The number of classified sequences per sample ranged from 23,515 to 39,259. Bacterial diversity was more phylum rich in grassland soils than in forest soils. The dominant taxonomic groups across all samples (>1% of all sequences) were Acidobacteria, Alphaproteobacteria, Actinobacteria, Betaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, and Firmicutes. Significant variations in relative abundances of bacterial phyla and proteobacterial classes, including Actinobacteria, Firmicutes, Verrucomicrobia, Cyanobacteria, Gemmatimonadetes and Alphaproteobacteria, between the land use types forest and grassland were observed. At the genus level, significant differences were also recorded for the dominant genera Phenylobacter, Bacillus, Kribbella, Streptomyces, Agromyces, and Defluviicoccus. In addition, soil bacterial community structure showed significant differences between beech and spruce forest soils. The relative abundances of bacterial groups at different taxonomic levels correlated with soil pH, but little or no relationships to management type and other soil properties were found. Soil bacterial community composition and diversity of the six analyzed management types showed significant differences between the land use types grassland and forest. Furthermore, bacterial community structure was largely driven by tree species and soil pH.PLoS ONE 01/2011; 6(2):e17000. · 4.09 Impact Factor -
Article: Comparative genomics and transcriptomics of Propionibacterium acnes.
[show abstract] [hide abstract]
ABSTRACT: The anaerobic gram-positive bacterium Propionibacterium acnes is a human skin commensal that is occasionally associated with inflammatory diseases. Recent work has indicated that evolutionary distinct lineages of P. acnes play etiologic roles in disease while others are associated with maintenance of skin homeostasis. To shed light on the molecular basis for differential strain properties, we carried out genomic and transcriptomic analysis of distinct P. acnes strains. We sequenced the genome of the P. acnes strain 266, a type I-1a strain. Comparative genome analysis of strain 266 and four other P. acnes strains revealed that overall genome plasticity is relatively low; however, a number of island-like genomic regions, encoding a variety of putative virulence-associated and fitness traits differ between phylotypes, as judged from PCR analysis of a collection of P. acnes strains. Comparative transcriptome analysis of strains KPA171202 (type I-2) and 266 during exponential growth revealed inter-strain differences in gene expression of transport systems and metabolic pathways. In addition, transcript levels of genes encoding possible virulence factors such as dermatan-sulphate adhesin, polyunsaturated fatty acid isomerase, iron acquisition protein HtaA and lipase GehA were upregulated in strain 266. We investigated differential gene expression during exponential and stationary growth phases. Genes encoding components of the energy-conserving respiratory chain as well as secreted and virulence-associated factors were transcribed during the exponential phase, while the stationary growth phase was characterized by upregulation of genes involved in stress responses and amino acid metabolism. Our data highlight the genomic basis for strain diversity and identify, for the first time, the actively transcribed part of the genome, underlining the important role growth status plays in the inflammation-inducing activity of P. acnes. We argue that the disease-causing potential of different P. acnes strains is not only determined by the phylotype-specific genome content but also by variable gene expression.PLoS ONE 01/2011; 6(6):e21581. · 4.09 Impact Factor -
Article: A novel metagenomic short-chain dehydrogenase/reductase attenuates Pseudomonas aeruginosa biofilm formation and virulence on Caenorhabditis elegans.
[show abstract] [hide abstract]
ABSTRACT: In Pseudomonas aeruginosa, the expression of a number of virulence factors, as well as biofilm formation, are controlled by quorum sensing (QS). N-Acylhomoserine lactones (AHLs) are an important class of signaling molecules involved in bacterial QS and in many pathogenic bacteria infection and host colonization are AHL-dependent. The AHL signaling molecules are subject to inactivation mainly by hydrolases (Enzyme Commission class number EC 3) (i.e. N-acyl-homoserine lactonases and N-acyl-homoserine-lactone acylases). Only little is known on quorum quenching mechanisms of oxidoreductases (EC 1). Here we report on the identification and structural characterization of the first NADP-dependent short-chain dehydrogenase/reductase (SDR) involved in inactivation of N-(3-oxo-dodecanoyl)-L-homoserine lactone (3-oxo-C(12)-HSL) and derived from a metagenome library. The corresponding gene was isolated from a soil metagenome and designated bpiB09. Heterologous expression and crystallographic studies established BpiB09 as an NADP-dependent reductase. Although AHLs are probably not the native substrate of this metagenome-derived enzyme, its expression in P. aeruginosa PAO1 resulted in significantly reduced pyocyanin production, decreased motility, poor biofilm formation and absent paralysis of Caenorhabditis elegans. Furthermore, a genome-wide transcriptome study suggested that the level of lasI and rhlI transcription together with 36 well known QS regulated genes was significantly (≥10-fold) affected in P. aeruginosa strains expressing the bpiB09 gene in pBBR1MCS-5. Thus AHL oxidoreductases could be considered as potent tools for the development of quorum quenching strategies.PLoS ONE 01/2011; 6(10):e26278. · 4.09 Impact Factor -
Article: Structural peculiarities of linear megaplasmid, pLMA1, from Micrococcus luteus interfere with pyrosequencing reads assembly.
[show abstract] [hide abstract]
ABSTRACT: Different strains of Micrococcus luteus, isolated from high-altitude Argentinean wetlands, were recently reported to harbour the linear plasmids pLMA1, pLMH5 and pLMV7, all of which with 5'-covalently attached terminal proteins. The link between pLMA1 and the host's erythromycin resistance as well as further presumptive qualities prompted us to perform a detailed characterization. When the 454 technology was applied for direct sequencing of gel-purified pLMA1, assembly of the reads was impossible. However, combined Sanger/454 sequencing of cloned pLMA1 fragments, covering altogether 23 kb of the 110-kb spanning plasmid, allowed numerous sequence repeats of varying in lengths to be identified thus rendering an explanation for the above 454 assembly failure. A large number of putative transposase genes were identified as well. Furthermore, a region with five putative iteron sequences is possibly involved in pLMA1 replication.Biotechnology Letters 12/2010; 32(12):1853-62. · 1.68 Impact Factor -
Article: Horizon-specific bacterial community composition of German grassland soils, as revealed by pyrosequencing-based analysis of 16S rRNA genes.
[show abstract] [hide abstract]
ABSTRACT: The diversity of bacteria in soil is enormous, and soil bacterial communities can vary greatly in structure. Here, we employed a pyrosequencing-based analysis of the V2-V3 16S rRNA gene region to characterize the overall and horizon-specific (A and B horizons) bacterial community compositions in nine grassland soils, which covered three different land use types. The entire data set comprised 752,838 sequences, 600,544 of which could be classified below the domain level. The average number of sequences per horizon was 41,824. The dominant taxonomic groups present in all samples and horizons were the Acidobacteria, Betaproteobacteria, Actinobacteria, Gammaproteobacteria, Alphaproteobacteria, Deltaproteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes. Despite these overarching dominant taxa, the abundance, diversity, and composition of bacterial communities were horizon specific. In almost all cases, the estimated bacterial diversity (H') was higher in the A horizons than in the corresponding B horizons. In addition, the H' was positively correlated with the organic carbon content, the total nitrogen content, and the C-to-N ratio, which decreased with soil depth. It appeared that lower land use intensity results in higher bacterial diversity. The majority of sequences affiliated with the Actinobacteria, Bacteroidetes, Cyanobacteria, Fibrobacteres, Firmicutes, Spirochaetes, Verrucomicrobia, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were derived from A horizons, whereas the majority of the sequences related to Acidobacteria, Chloroflexi, Gemmatimonadetes, Nitrospira, TM7, and WS3 originated from B horizons. The distribution of some bacterial phylogenetic groups and subgroups in the different horizons correlated with soil properties such as organic carbon content, total nitrogen content, or microbial biomass.Applied and environmental microbiology 10/2010; 76(20):6751-9. · 3.69 Impact Factor
Top co-authors
Top Journals
Institutions
-
2011–2012
-
Ernst-Moritz-Arndt-Universität Greifswald
Greifswald, Mecklenburg-Vorpommern, Germany
-
-
2010–2011
-
Georg-August-Universität Göttingen
- Institute of Microbiology and Genetics
Göttingen, Lower Saxony, Germany
-
