@article{BerghoffKonzerManketal.2013, author = {Berghoff, Bork A. and Konzer, Anne and Mank, Nils N. and Looso, Mario and Rische, Tom and F{\"o}rstner, Konrad U. and Kr{\"u}ger, Marcus and Klug, Gabriele}, title = {Integrative "Omics"-Approach Discovers Dynamic and Regulatory Features of Bacterial Stress Responses}, series = {PLOS Genetics}, volume = {9}, journal = {PLOS Genetics}, number = {6}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1003576}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127587}, pages = {e1003576}, year = {2013}, abstract = {Bacteria constantly face stress conditions and therefore mount specific responses to ensure adaptation and survival. Stress responses were believed to be predominantly regulated at the transcriptional level. In the phototrophic bacterium Rhodobacter sphaeroides the response to singlet oxygen is initiated by alternative sigma factors. Further adaptive mechanisms include post-transcriptional and post-translational events, which have to be considered to gain a deeper understanding of how sophisticated regulation networks operate. To address this issue, we integrated three layers of regulation: (1) total mRNA levels at different time-points revealed dynamics of the transcriptome, (2) mRNAs in polysome fractions reported on translational regulation (translatome), and (3) SILAC-based mass spectrometry was used to quantify protein abundances (proteome). The singlet oxygen stress response exhibited highly dynamic features regarding short-term effects and late adaptation, which could in part be assigned to the sigma factors RpoE and RpoH2 generating distinct expression kinetics of corresponding regulons. The occurrence of polar expression patterns of genes within stress-inducible operons pointed to an alternative of dynamic fine-tuning upon stress. In addition to transcriptional activation, we observed significant induction of genes at the post-transcriptional level (translatome), which identified new putative regulators and assigned genes of quorum sensing to the singlet oxygen stress response. Intriguingly, the SILAC approach explored the stress-dependent decline of photosynthetic proteins, but also identified 19 new open reading frames, which were partly validated by RNA-seq. We propose that comparative approaches as presented here will help to create multi-layered expression maps on the system level ("expressome"). Finally, intense mass spectrometry combined with RNA-seq might be the future tool of choice to re-annotate genomes in various organisms and will help to understand how they adapt to alternating conditions.}, language = {en} } @article{AbdaKrysciakKrohnMoltetal.2015, author = {Abda, Ebrahim M. and Krysciak, Dagmar and Krohn-Molt, Ines and Mamat, Uwe and Schmeisser, Christel and F{\"o}rstner, Konrad U. and Schaible, Ulrich E. and Kohi, Thomas A. and Nieman, Stefan and Streit, Wolfgang R.}, title = {Phenotypic Heterogeneity Affects Stenotrophomonas maltophilia K279a Colony Morphotypes and \(\beta\)-Lactamase Expression}, series = {Frontiers in Microbiology}, volume = {6}, journal = {Frontiers in Microbiology}, number = {1373}, doi = {10.3389/fmicb.2015.01373}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136446}, year = {2015}, abstract = {Phenotypic heterogeneity at the cellular level in response to various stresses, e.g., antibiotic treatment has been reported for a number of bacteria. In a clonal population, cell-to-cell variation may result in phenotypic heterogeneity that is a mechanism to survive changing environments including antibiotic therapy. Stenotrophomonas rnaltophilia has been frequently isolated from cystic fibrosis patients, can cause numerous infections in other organs and tissues, and is difficult to treat due to antibiotic resistances. S. maltophilia K279a produces the Li and L2 beta-lactamases in response to beta-lactam treatment. Here we report that the patient isolate S. rnaltophilia K279a diverges into cellular subpopulations with distinct but reversible morphotypes of small and big colonies when challenged with ampicillin. This observation is consistent with the formation of elongated chains of bacteria during exponential growth phase and the occurrence of mainly rod-shaped cells in liquid media. RNA-seq analysis of small versus big colonies revealed differential regulation of at least seven genes among the colony morphotypes. Among those, bleu and bla(L2) were transcriptionally the most strongly upregulated genes. Promoter fusions of b/a(L1) and b/a(L2) genes indicated that expression of both genes is also subject to high levels of phenotypic heterogeneous expression on a single cell level. Additionally, the comE homolog was found to be differentially expressed in homogenously versus heterogeneously bla(L2) expressing cells as identified by RNA(seq) analysis. Overexpression of cornE in S. maltophilia K279a reduced the level of cells that were in a bla(L2)-ON mode to 1\% or lower. Taken together, our data provide strong evidence that S. maltophilia K279a populations develop phenotypic heterogeneity in an ampicillin challenged model. This cellular variability is triggered by regulation networks including b/a(L1), b/a(L2), and comE.}, language = {en} } @article{JaegerFoerstnerSharmaetal.2014, author = {J{\"a}ger, Dominik and F{\"o}rstner, Konrad U. and Sharma, Cynthia M. and Santangelo, Thomas J. and Reeve, John N.}, title = {Primary transcriptome map of the hyperthermophilic archaeon Thermococcus kodakarensis}, series = {BMC Genomics}, volume = {15}, journal = {BMC Genomics}, number = {684}, issn = {1471-2164}, doi = {10.1186/1471-2164-15-684}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120966}, year = {2014}, abstract = {Background Prokaryotes have relatively small genomes, densely-packed with protein-encoding sequences. RNA sequencing has, however, revealed surprisingly complex transcriptomes and here we report the transcripts present in the model hyperthermophilic Archaeon, Thermococcus kodakarensis, under different physiological conditions. Results Sequencing cDNA libraries, generated from RNA isolated from cells under different growth and metabolic conditions has identified >2,700 sites of transcription initiation, established a genome-wide map of transcripts, and consensus sequences for transcription initiation and post-transcription regulatory elements. The primary transcription start sites (TSS) upstream of 1,254 annotated genes, plus 644 primary TSS and their promoters within genes, are identified. Most mRNAs have a 5'-untranslated region (5'-UTR) 10 to 50 nt long (median = 16 nt), but ~20\% have 5'-UTRs from 50 to 300 nt long and ~14\% are leaderless. Approximately 50\% of mRNAs contain a consensus ribosome binding sequence. The results identify TSS for 1,018 antisense transcripts, most with sequences complementary to either the 5'- or 3'-region of a sense mRNA, and confirm the presence of transcripts from all three CRISPR loci, the RNase P and 7S RNAs, all tRNAs and rRNAs and 69 predicted snoRNAs. Two putative riboswitch RNAs were present in growing but not in stationary phase cells. The procedure used is designed to identify TSS but, assuming that the number of cDNA reads correlates with transcript abundance, the results also provide a semi-quantitative documentation of the differences in T. kodakarensis genome expression under different growth conditions and confirm previous observations of substrate-dependent specific gene expression. Many previously unanticipated small RNAs have been identified, some with relative low GC contents (≤50\%) and sequences that do not fold readily into base-paired secondary structures, contrary to the classical expectations for non-coding RNAs in a hyperthermophile. Conclusion The results identify >2,700 TSS, including almost all of the primary sites of transcription initiation upstream of annotated genes, plus many secondary sites, sites within genes and sites resulting in antisense transcripts. The T. kodakarensis genome is small (~2.1 Mbp) and tightly packed with protein-encoding genes, but the transcriptomes established also contain many non-coding RNAs and predict extensive RNA-based regulation in this model Archaeon.}, language = {en} } @article{MoellerOverloeperFoerstneretal.2014, author = {M{\"o}ller, Philip and Overl{\"o}per, Aaron and F{\"o}rstner, Konrad U. and Wen, Tuan-Nan and Sharma, Cynthia M. and Lai, Erh-Min and Narberhaus, Franz}, title = {Profound Impact of Hfq on Nutrient Acquisition, Metabolism and Motility in the Plant Pathogen Agrobacterium tumefaciens}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {10}, doi = {10.1371/journal.pone.0110427}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-114874}, pages = {e110427}, year = {2014}, abstract = {As matchmaker between mRNA and sRNA interactions, the RNA chaperone Hfq plays a key role in riboregulation of many bacteria. Often, the global influence of Hfq on the transcriptome is reflected by substantially altered proteomes and pleiotropic phenotypes in hfq mutants. Using quantitative proteomics and co-immunoprecipitation combined with RNA-sequencing (RIP-seq) of Hfq-bound RNAs, we demonstrate the pervasive role of Hfq in nutrient acquisition, metabolism and motility of the plant pathogen Agrobacterium tumefaciens. 136 of 2544 proteins identified by iTRAQ (isobaric tags for relative and absolute quantitation) were affected in the absence of Hfq. Most of them were associated with ABC transporters, general metabolism and motility. RIP-seq of chromosomally encoded Hfq 3xFlag revealed 1697 mRNAs and 209 non-coding RNAs (ncRNAs) associated with Hfq. 56 ncRNAs were previously undescribed. Interestingly, 55\% of the Hfq-bound ncRNAs were encoded antisense (as) to a protein-coding sequence suggesting that A. tumefaciens Hfq plays an important role in asRNA-target interactions. The exclusive enrichment of 296 mRNAs and 31 ncRNAs under virulence conditions further indicates a role for post-transcriptional regulation in A. tumefaciens-mediated plant infection. On the basis of the iTRAQ and RIP-seq data, we assembled a comprehensive model of the Hfq core regulon in A. tumefaciens.}, language = {en} } @article{ReynoldsCliffeFoerstneretal.2014, author = {Reynolds, David and Cliffe, Laura and F{\"o}rstner, Konrad U. and Hon, Chung-Chau and Siegel, T. Nicolai and Sabatini, Robert}, title = {Regulation of transcription termination by glucosylated hydroxymethyluracil, base J, in Leishmania major and Trypanosoma brucei}, series = {Nucleic Acids Research}, volume = {42}, journal = {Nucleic Acids Research}, number = {15}, doi = {10.1093/nar/gku714}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117863}, pages = {9717-9729}, year = {2014}, abstract = {Base J, beta-d-glucosyl-hydroxymethyluracil, is an epigenetic modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. J is enriched at sites involved in RNA polymerase ( RNAP) II initiation and termination. Reduction of J in Leishmania tarentolae via growth in BrdU resulted in cell death and indicated a role of J in the regulation of RNAP II termination. To further explore J function in RNAP II termination among kinetoplastids and avoid indirect effects associated with BrdU toxicity and genetic deletions, we inhibited J synthesis in Leishmania major and Trypanosoma brucei using DMOG. Reduction of J in L. major resulted in genome-wide defects in transcription termination at the end of polycistronic gene clusters and the generation of antisense RNAs, without cell death. In contrast, loss of J in T. brucei did not lead to genome-wide termination defects; however, the loss of J at specific sites within polycistronic gene clusters led to altered transcription termination and increased expression of downstream genes. Thus, J regulation of RNAP II transcription termination genome-wide is restricted to Leishmania spp., while in T. brucei it regulates termination and gene expression at specific sites within polycistronic gene clusters.}, language = {en} } @article{FoerstnerReuscherHaberzettletal.2018, author = {F{\"o}rstner, Konrad U and Reuscher, Carina M and Haberzettl, Kerstin and Weber, Lennart and Klug, Gabriele}, title = {RNase E cleavage shapes the transcriptome of Rhodobacter sphaeroides and strongly impacts phototrophic growth}, series = {Life Science Alliance}, volume = {1}, journal = {Life Science Alliance}, number = {4}, doi = {10.26508/lsa.201800080}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177139}, pages = {e201800080}, year = {2018}, abstract = {Bacteria adapt to changing environmental conditions by rapid changes in their transcriptome. This is achieved not only by adjusting rates of transcription but also by processing and degradation of RNAs. We applied TIER-Seq (transiently inactivating an endoribonuclease followed by RNA-Seq) for the transcriptome-wide identification of RNase E cleavage sites and of 5′ RNA ends, which are enriched when RNase E activity is reduced in Rhodobacter sphaeroides. These results reveal the importance of RNase E for the maturation and turnover of mRNAs, rRNAs, and sRNAs in this guanine-cytosine-rich α-proteobacterium, some of the latter have well-described functions in the oxidative stress response. In agreement with this, a role of RNase E in the oxidative stress response is demonstrated. A remarkably strong phenotype of a mutant with reduced RNase E activity was observed regarding the formation of photosynthetic complexes and phototrophic growth, whereas there was no effect on chemotrophic growth.}, language = {en} } @article{RemesBerghoffFoerstneretal.2014, author = {Remes, Bernhard and Berghoff, Bork A. and F{\"o}rstner, Konrad U. and Klug, Gabriele}, title = {Role of oxygen and the OxyR protein in the response to iron limitation in Rhodobacter sphaeroides}, series = {BMC Genomics}, volume = {15}, journal = {BMC Genomics}, number = {794}, issn = {1471-2164}, doi = {10.1186/1471-2164-15-794}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115357}, year = {2014}, abstract = {Background: High intracellular levels of unbound iron can contribute to the production of reactive oxygen species (ROS) via the Fenton reaction, while depletion of iron limits the availability of iron-containing proteins, some of which have important functions in defence against oxidative stress. Vice versa increased ROS levels lead to the damage of proteins with iron sulphur centres. Thus, organisms have to coordinate and balance their responses to oxidative stress and iron availability. Our knowledge of the molecular mechanisms underlying the co-regulation of these responses remains limited. To discriminate between a direct cellular response to iron limitation and indirect responses, which are the consequence of increased levels of ROS, we compared the response of the alpha-proteobacterium Rhodobacter sphaeroides to iron limitation in the presence or absence of oxygen. Results: One third of all genes with altered expression under iron limitation showed a response that was independent of oxygen availability. The other iron-regulated genes showed different responses in oxic or anoxic conditions and were grouped into six clusters based on the different expression profiles. For two of these clusters, induction in response to iron limitation under oxic conditions was dependent on the OxyR regulatory protein. An OxyR mutant showed increased ROS production and impaired growth under iron limitation. Conclusion: Some R. sphaeroides genes respond to iron limitation irrespective of oxygen availability. These genes therefore reflect a "core iron response" that is independent of potential ROS production under oxic, iron-limiting conditions. However, the regulation of most of the iron-responsive genes was biased by oxygen availability. Most strikingly, the OxyR-dependent activation of a subset of genes upon iron limitation under oxic conditions, including many genes with a role in iron metabolism, revealed that elevated ROS levels were an important trigger for this response. OxyR thus provides a regulatory link between the responses to oxidative stress and to iron limitation in R. sphaeroides.}, language = {en} } @article{MuellerWindhofMaximovetal.2013, author = {M{\"u}ller, Sara and Windhof, Indra M. and Maximov, Vladimir and Jurkowski, Tomasz and Jeltsch, Albert and F{\"o}rstner, Konrad U. and Sharma, Cynthia M. and Gr{\"a}f, Ralph and Nellen, Wolfgang}, title = {Target recognition, RNA methylation activity and transcriptional regulation of the Dictyostelium discoideum Dnmt2-homologue (DnmA)}, series = {Nucleic Acids Research}, volume = {41}, journal = {Nucleic Acids Research}, number = {18}, issn = {1362-4962}, doi = {10.1093/nar/gkt634}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123149}, pages = {8615-8627}, year = {2013}, abstract = {Although the DNA methyltransferase 2 family is highly conserved during evolution and recent reports suggested a dual specificity with stronger activity on transfer RNA (tRNA) than DNA substrates, the biological function is still obscure. We show that the Dictyostelium discoideum Dnmt2-homologue DnmA is an active tRNA methyltransferase that modifies C38 in \(tRNA^{Asp(GUC)}\) in vitro and in vivo. By an ultraviolet-crosslinking and immunoprecipitation approach, we identified further DnmA targets. This revealed specific tRNA fragments bound by the enzyme and identified \(tRNA^{Glu(CUC/UUC)}\) and \(tRNA^{Gly(GCC)}\) as new but weaker substrates for both human Dnmt2 and DnmA in vitro but apparently not in vivo. Dnmt2 enzymes form transient covalent complexes with their substrates. The dynamics of complex formation and complex resolution reflect methylation efficiency in vitro. Quantitative PCR analyses revealed alterations in dnmA expression during development, cell cycle and in response to temperature stress. However, dnmA expression only partially correlated with tRNA methylation in vivo. Strikingly, dnmA expression in the laboratory strain AX2 was significantly lower than in the NC4 parent strain. As expression levels and binding of DnmA to a target in vivo are apparently not necessarily accompanied by methylation, we propose an additional biological function of DnmA apart from methylation.}, language = {en} } @article{EskenGorisGadkarietal.2020, author = {Esken, Jens and Goris, Tobias and Gadkari, Jennifer and Bischler, Thorsten and F{\"o}rstner, Konrad U. and Sharma, Cynthia M. and Diekert, Gabriele and Schubert, Torsten}, title = {Tetrachloroethene respiration in Sulfurospirillum species is regulated by a two-component system as unraveled by comparative genomics, transcriptomics, and regulator binding studies}, series = {MicrobiologyOpen}, volume = {9}, journal = {MicrobiologyOpen}, number = {12}, doi = {10.1002/mbo3.1138}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225754}, year = {2020}, abstract = {Energy conservation via organohalide respiration (OHR) in dehalogenating Sulfurospirillum species is an inducible process. However, the gene products involved in tetrachloroethene (PCE) sensing and signal transduction have not been unambiguously identified. Here, genome sequencing of Sulfurospirillum strains defective in PCE respiration and comparative genomics, which included the PCE-respiring representatives of the genus, uncovered the genetic inactivation of a two-component system (TCS) in the OHR gene region of the natural mutants. The assumption that the TCS gene products serve as a PCE sensor that initiates gene transcription was supported by the constitutive low-level expression of the TCS operon in fumarate-adapted cells of Sulfurospirillum multivorans. Via RNA sequencing, eight transcriptional units were identified in the OHR gene region, which includes the TCS operon, the PCE reductive dehalogenase operon, the gene cluster for norcobamide biosynthesis, and putative accessory genes with unknown functions. The OmpR-family response regulator (RR) encoded in the TCS operon was functionally characterized by promoter-binding assays. The RR bound a cis-regulatory element that contained a consensus sequence of a direct repeat (CTATW) separated by 17 bp. Its location either overlapping the -35 box or 50 bp further upstream indicated different regulatory mechanisms. Sequence variations in the regulator binding sites identified in the OHR gene region were in accordance with differences in the transcript levels of the respective gene clusters forming the PCE regulon. The results indicate the presence of a fine-tuned regulatory network controlling PCE metabolism in dehalogenating Sulfurospirillum species, a group of metabolically versatile organohalide-respiring bacteria.}, language = {en} } @article{GroteKrysciakPetersenetal.2016, author = {Grote, Jessica and Krysciak, Dagmar and Petersen, Katrin and G{\"u}llert, Simon and Schmeisser, Christel and F{\"o}rstner, Konrad U. and Krishnan, Hari B. and Schwalbe, Harald and Kubatova, Nina and Streit, Wolfgang R.}, title = {The Absence of the N-acyl-homoserine-lactone Autoinducer Synthase Genes tral and ngrl Increases the Copy Number of the Symbiotic Plasmid in Sinorhizobium fredii NGR234}, series = {Frontiers in Microbiology}, volume = {7}, journal = {Frontiers in Microbiology}, number = {1858}, doi = {10.3389/fmicb.2016.01858}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165185}, year = {2016}, abstract = {Plant-released flavonoids induce the transcription of symbiotic genes in rhizobia and one of the first bacterial responses is the synthesis of so called Nod factors. They are responsible for the initial root hair curling during onset of root nodule development. This signal exchange is believed to be essential for initiating the plant symbiosis with rhizobia affiliated with the Alphaproteobacteria. Here, we provide evidence that in the broad host range strain Sinorhizobium fredii NGR234 the complete lack of quorum sensing molecules results in an elevated copy number of its symbiotic plasmid (pNGR234a). This in turn triggers the expression of symbiotic genes and the production of Nod factors in the absence of plant signals. Therefore, increasing the copy number of specific plasmids could be a widespread mechanism of specialized bacterial populations to bridge gaps in signaling cascades.}, language = {en} } @article{UlbrichtNickelWeidenbachetal.2020, author = {Ulbricht, Andrea and Nickel, Lisa and Weidenbach, Katrin and Vargas Gebauer, Herman and Kießling, Claudia and F{\"o}rstner, Konrad U. and Schmitz, Ruth A.}, title = {The CARF protein MM_0565 affects transcription of the casposon-encoded cas1-solo gene in Methanosarcina mazei G{\"o}1}, series = {Biomolecules}, volume = {10}, journal = {Biomolecules}, number = {8}, issn = {2218-273X}, doi = {10.3390/biom10081161}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-211097}, year = {2020}, abstract = {Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) loci are found in bacterial and archaeal genomes where they provide the molecular machinery for acquisition of immunity against foreign DNA. In addition to the cas genes fundamentally required for CRISPR activity, a second class of genes is associated with the CRISPR loci, of which many have no reported function in CRISPR-mediated immunity. Here, we characterize MM_0565 associated to the type I-B CRISPR-locus of Methanosarcina mazei G{\"o}1. We show that purified MM_0565 composed of a CRISPR-Cas Associated Rossmann Fold (CARF) and a winged helix-turn-helix domain forms a dimer in solution; in vivo, the dimeric MM_0565 is strongly stabilized under high salt stress. While direct effects on CRISPR-Cas transcription were not detected by genetic approaches, specific binding of MM_0565 to the leader region of both CRISPR-Cas systems was observed by microscale thermophoresis and electromobility shift assays. Moreover, overexpression of MM_0565 strongly induced transcription of the cas1-solo gene located in the recently reported casposon, the gene product of which shows high similarity to classical Cas1 proteins. Based on our findings, and taking the absence of the expressed CRISPR locus-encoded Cas1 protein into account, we hypothesize that MM_0565 might modulate the activity of the CRISPR systems on different levels.}, language = {en} } @article{WestermannVenturiniSellinetal.2019, author = {Westermann, Alexander J. and Venturini, Elisa and Sellin, Mikael E. and F{\"o}rstner, Konrad U. and Hardt, Wolf-Dietrich and Vogel, J{\"o}rg}, title = {The major RNA-binding protein ProQ impacts virulence gene expression in Salmonella enterica serovar Typhimurium}, series = {mBio}, volume = {10}, journal = {mBio}, number = {1}, doi = {10.1128/mBio.02504-18}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177722}, pages = {e02504-18}, year = {2019}, abstract = {FinO domain proteins such as ProQ of the model pathogen Salmonella enterica have emerged as a new class of major RNA-binding proteins in bacteria. ProQ has been shown to target hundreds of transcripts, including mRNAs from many virulence regions, but its role, if any, in bacterial pathogenesis has not been studied. Here, using a Dual RNA-seq approach to profile ProQ-dependent gene expression changes as Salmonella infects human cells, we reveal dysregulation of bacterial motility, chemotaxis, and virulence genes which is accompanied by altered MAPK (mitogen-activated protein kinase) signaling in the host. Comparison with the other major RNA chaperone in Salmonella, Hfq, reinforces the notion that these two global RNA-binding proteins work in parallel to ensure full virulence. Of newly discovered infection-associated ProQ-bound small noncoding RNAs (sRNAs), we show that the 3′UTR-derived sRNA STnc540 is capable of repressing an infection-induced magnesium transporter mRNA in a ProQ-dependent manner. Together, this comprehensive study uncovers the relevance of ProQ for Salmonella pathogenesis and highlights the importance of RNA-binding proteins in regulating bacterial virulence programs. IMPORTANCE The protein ProQ has recently been discovered as the centerpiece of a previously overlooked "third domain" of small RNA-mediated control of gene expression in bacteria. As in vitro work continues to reveal molecular mechanisms, it is also important to understand how ProQ affects the life cycle of bacterial pathogens as these pathogens infect eukaryotic cells. Here, we have determined how ProQ shapes Salmonella virulence and how the activities of this RNA-binding protein compare with those of Hfq, another central protein in RNA-based gene regulation in this and other bacteria. To this end, we apply global transcriptomics of pathogen and host cells during infection. In doing so, we reveal ProQ-dependent transcript changes in key virulence and host immune pathways. Moreover, we differentiate the roles of ProQ from those of Hfq during infection, for both coding and noncoding transcripts, and provide an important resource for those interested in ProQ-dependent small RNAs in enteric bacteria.}, language = {en} } @article{BurySoundararajanBhartietal.2018, author = {Bury, Susanne and Soundararajan, Manonmani and Bharti, Richa and von B{\"u}nau, Rudolf and F{\"o}rstner, Konrad U. and Oelschlaeger, Tobias A.}, title = {The probiotic escherichia coli strain Nissle 1917 combats lambdoid bacteriophages stx and lambda}, series = {Frontiers in Microbiology}, volume = {9}, journal = {Frontiers in Microbiology}, doi = {10.3389/fmicb.2018.00929}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221960}, year = {2018}, abstract = {Shiga toxin (Stx) producing E. coli (STEC) such as Enterohemorrhagic E. coli (EHEC) are the major cause of foodborne illness in humans. In vitro studies showed the probiotic Escherichia coil strain Nissle 1917 (EcN) to efficiently inhibit the production of Stx. Life threatening EHEC strains as for example the serotype 0104:H4, responsible for the great outbreak in 2011 in Germany, evolutionary developed from certain E. coll strains which got infected by stx2-encoding lambdoid phages turning the E. coil into lysogenic and subsequently Stx producing strains. Since antibiotics induce stx genes and Stx production, EHEC infected persons are not recommended to be treated with antibiotics. Therefore, EcN might be an alternative medication. However, because even commensal E. coli strains might be converted into Stx-producers after becoming host to a stx encoding prophage, we tested EcN for stx-phage genome integration. Our experiments revealed the resistance of EcN toward not only stx-phages but also against lambda-phages. This resistance was not based on the lack of or by mutated phage receptors. Rather it involved the expression of a phage repressor (pr) gene of a defective prophage in EcN which was able to partially protect E. coli K-12 strain MG1655 against stx and lambda phage infection. Furthermore, we observed EcN to inactivate phages and thereby to protect E. coli K-12 strains against infection by stx- as well as lambda-phages. Inactivation of lambda-phages was due to binding of lambda-phages to LamB of EcN whereas inactivation of stx-phages was caused by a thermostable protein of EcN. These properties together with its ability to inhibit Stx production make EcN a good candidate for the prevention of illness caused by EHEC and probably for the treatment of already infected people.}, language = {en} } @article{LavyshSokolovaSlashchevaetal.2017, author = {Lavysh, Daria and Sokolova, Maria and Slashcheva, Marina and F{\"o}rstner, Konrad U. and Severinov, Konstantin}, title = {Transcription profiling of "bacillus subtilis" cells infected with AR9, a giant phage encoding two multisubunit RNA polymerases}, series = {mBio}, volume = {8}, journal = {mBio}, number = {1}, doi = {10.1128/mBio.02041-16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181810}, year = {2017}, abstract = {Bacteriophage AR9 is a recently sequenced jumbo phage that encodes two multisubunit RNA polymerases. Here we investigated the AR9 transcription strategy and the effect of AR9 infection on the transcription of its host, Bacillus subtilis. Analysis of whole-genome transcription revealed early, late, and continuously expressed AR9 genes. Alignment of sequences upstream of the 5′ ends of AR9 transcripts revealed consensus sequences that define early and late phage promoters. Continuously expressed AR9 genes have both early and late promoters in front of them. Early AR9 transcription is independent of protein synthesis and must be determined by virion RNA polymerase injected together with viral DNA. During infection, the overall amount of host mRNAs is significantly decreased. Analysis of relative amounts of host transcripts revealed notable differences in the levels of some mRNAs. The physiological significance of up- or downregulation of host genes for AR9 phage infection remains to be established. AR9 infection is significantly affected by rifampin, an inhibitor of host RNA polymerase transcription. The effect is likely caused by the antibiotic-induced killing of host cells, while phage genome transcription is solely performed by viral RNA polymerases.}, language = {en} } @article{MietchenHagedornFoerstneretal.2011, author = {Mietchen, Daniel and Hagedorn, Gregor and F{\"o}rstner, Konrad U. and Kubke, M Fabiana and Koltzenburg, Claudia and Hahnel, Mark J. and Penev, Lyubomir}, title = {Wikis in scholarly publishing}, doi = {10.3233/ISU-2011-0621}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-87770}, year = {2011}, abstract = {Scientific research is a process concerned with the creation, collective accumulation, contextualization, updating and maintenance of knowledge. Wikis provide an environment that allows to collectively accumulate, contextualize, update and maintain knowledge in a coherent and transparent fashion. Here, we examine the potential of wikis as platforms for scholarly publishing. In the hope to stimulate further discussion, the article itself was drafted on Species-ID - a wiki that hosts a prototype for wiki-based scholarly publishing - where it can be updated, expanded or otherwise improved.}, subject = {Elektronisches Publizieren}, language = {en} }