@article{NguyenSaisingTribellietal.2019, author = {Nguyen, Minh-Thu and Saising, Jongkon and Tribelli, Paula Maria and Nega, Mulugeta and Diene, Seydina M. and Fran{\c{c}}ois, Patrice and Schrenzel, Jacques and Spr{\"o}er, Cathrin and Bunk, Boyke and Ebner, Patrick and Hertlein, Tobias and Kumari, Nimerta and H{\"a}rtner, Thomas and Wistuba, Dorothee and Voravuthikunchai, Supayang P. and M{\"a}der, Ulrike and Ohlsen, Knut and G{\"o}tz, Friedrich}, title = {Inactivation of farR Causes High Rhodomyrtone Resistance and Increased Pathogenicity in Staphylococcus aureus}, series = {Frontiers in Microbiology}, volume = {10}, journal = {Frontiers in Microbiology}, doi = {10.3389/fmicb.2019.01157}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224117}, year = {2019}, abstract = {Rhodomyrtone (Rom) is an acylphloroglucinol antibiotic originally isolated from leaves of Rhodomyrtus tomentosa. Rom targets the bacterial membrane and is active against a wide range of Gram-positive bacteria but the exact mode of action remains obscure. Here we isolated and characterized a spontaneous Rom-resistant mutant from the model strain Staphylococcus aureus HG001 (RomR) to learn more about the resistance mechanism. We showed that Rom-resistance is based on a single point mutation in the coding region of farR [regulator of fatty acid (FA) resistance] that causes an amino acid change from Cys to Arg at position 116 in FarR, that affects FarR activity. Comparative transcriptome analysis revealed that mutated farR affects transcription of many genes in distinct pathways. FarR represses for example the expression of its own gene (farR), its flanking gene farE (effector of FA resistance), and other global regulators such as agr and sarA. All these genes were consequently upregulated in the RomR clone. Particularly the upregulation of agr and sarA leads to increased expression of virulence genes rendering the RomR clone more cytotoxic and more pathogenic in a mouse infection model. The Rom-resistance is largely due to the de-repression of farE. FarE is described as an efflux pump for linoleic and arachidonic acids. We observed an increased release of lipids in the RomR clone compared to its parental strain HG001. If farE is deleted in the RomR clone, or, if native farR is expressed in the RomR strain, the corresponding strains become hypersensitive to Rom. Overall, we show here that the high Rom-resistance is mediated by overexpression of farE in the RomR clone, that FarR is an important regulator, and that the point mutation in farR (RomR clone) makes the clone hyper-virulent.}, language = {en} } @article{MichauxHansenJennichesetal.2020, author = {Michaux, Charlotte and Hansen, Elisabeth E. and Jenniches, Laura and Gerovac, Milan and Barquist, Lars and Vogel, J{\"o}rg}, title = {Single-Nucleotide RNA Maps for the Two Major Nosocomial Pathogens Enterococcus faecalis and Enterococcus faecium}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {10}, journal = {Frontiers in Cellular and Infection Microbiology}, issn = {2235-2988}, doi = {10.3389/fcimb.2020.600325}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217947}, year = {2020}, abstract = {Enterococcus faecalis and faecium are two major representative clinical strains of the Enterococcus genus and are sadly notorious to be part of the top agents responsible for nosocomial infections. Despite their critical implication in worldwide public healthcare, essential and available resources such as deep transcriptome annotations remain poor, which also limits our understanding of post-transcriptional control small regulatory RNA (sRNA) functions in these bacteria. Here, using the dRNA-seq technique in combination with ANNOgesic analysis, we successfully mapped and annotated transcription start sites (TSS) of both E. faecalis V583 and E. faecium AUS0004 at single nucleotide resolution. Analyzing bacteria in late exponential phase, we capture ~40\% (E. faecalis) and 43\% (E. faecium) of the annotated protein-coding genes, determine 5′ and 3′ UTR (untranslated region) length, and detect instances of leaderless mRNAs. The transcriptome maps revealed sRNA candidates in both bacteria, some found in previous studies and new ones. Expression of candidate sRNAs is being confirmed under biologically relevant environmental conditions. This comprehensive global TSS mapping atlas provides a valuable resource for RNA biology and gene expression analysis in the Enterococci. It can be accessed online at www.helmholtz-hiri.de/en/datasets/enterococcus through an instance of the genomic viewer JBrowse.}, language = {en} } @article{OndruschKreft2011, author = {Ondrusch, Nicolai and Kreft, J{\"u}rgen}, title = {Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in \(Listeria\) \(monocytogenes\)}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0016151}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134050}, pages = {e16151}, year = {2011}, abstract = {Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat.}, language = {en} }