@article{HanzelmannJooFranzWachteletal.2016, author = {Hanzelmann, Dennis and Joo, Hwang-Soo and Franz-Wachtel, Mirita and Hertlein, Tobias and Stevanovic, Stefan and Macek, Boris and Wolz, Christiane and G{\"o}tz, Friedrich and Otto, Michael and Kretschmer, Dorothee and Peschel, Andreas}, title = {Toll-like receptor 2 activation depends on lipopeptide shedding by bacterial surfactants}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms12304}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165975}, pages = {12304}, year = {2016}, abstract = {Sepsis caused by Gram-positive bacterial pathogens is a major fatal disease but its molecular basis remains elusive. Toll-like receptor 2 (TLR2) has been implicated in the orchestration of inflammation and sepsis but its role appears to vary for different pathogen species and clones. Accordingly, Staphylococcus aureus clinical isolates differ substantially in their capacity to activate TLR2. Here we show that strong TLR2 stimulation depends on high-level production of phenol-soluble modulin (PSM) peptides in response to the global virulence activator Agr. PSMs are required for mobilizing lipoproteins, the TLR2 agonists, from the staphylococcal cytoplasmic membrane. Notably, the course of sepsis caused by PSM-deficient S. aureus is similar in wild-type and TLR2-deficient mice, but TLR2 is required for protection of mice against PSM-producing S. aureus. Thus, a crucial role of TLR2 depends on agonist release by bacterial surfactants. Modulation of this process may lead to new therapeutic strategies against Gram-positive infections.}, language = {en} } @article{DingemansMonsieursYuetal.2016, author = {Dingemans, Josef and Monsieurs, Pieter and Yu, Sung-Huan and Crabb{\´e}, Aur{\´e}lie and F{\"o}rstner, Konrad U. and Malfroot, Anne and Cornelis, Pierre and Van Houdt, Rob}, title = {Effect of Shear Stress on Pseudomonas aeruginosa Isolated from the Cystic Fibrosis Lung}, series = {mBio}, volume = {7}, journal = {mBio}, number = {4}, doi = {10.1128/mBio.00813-16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165821}, pages = {e00813-16}, year = {2016}, abstract = {Chronic colonization of the lungs by Pseudomonas aeruginosa is one of the major causes of morbidity and mortality in cystic fibrosis (CF) patients. To gain insights into the characteristic biofilm phenotype of P. aeruginosa in the CF lungs, mimicking the CF lung environment is critical. We previously showed that growth of the non-CF-adapted P. aeruginosa PAO1 strain in a rotating wall vessel, a device that simulates the low fluid shear (LS) conditions present in the CF lung, leads to the formation of in-suspension, self-aggregating biofilms. In the present study, we determined the phenotypic and transcriptomic changes associated with the growth of a highly adapted, transmissible P. aeruginosa CF strain in artificial sputum medium under LS conditions. Robust self-aggregating biofilms were observed only under LS conditions. Growth under LS conditions resulted in the upregulation of genes involved in stress response, alginate biosynthesis, denitrification, glycine betaine biosynthesis, glycerol metabolism, and cell shape maintenance, while genes involved in phenazine biosynthesis, type VI secretion, and multidrug efflux were downregulated. In addition, a number of small RNAs appeared to be involved in the response to shear stress. Finally, quorum sensing was found to be slightly but significantly affected by shear stress, resulting in higher production of autoinducer molecules during growth under high fluid shear (HS) conditions. In summary, our study revealed a way to modulate the behavior of a highly adapted P. aeruginosa CF strain by means of introducing shear stress, driving it from a biofilm lifestyle to a more planktonic lifestyle.}, language = {en} } @article{DugarSvenssonBischleretal.2016, author = {Dugar, Gaurav and Svensson, Sarah L. and Bischler, Thorsten and Waldchen, Sina and Reinhardt, Richard and Sauer, Markus and Sharma, Cynthia M.}, title = {The CsrA-FliW network controls polar localization of the dual-function flagellin mRNA in Campylobacter jejuni}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms11667}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173201}, year = {2016}, abstract = {The widespread CsrA/RsmA protein regulators repress translation by binding GGA motifs in bacterial mRNAs. CsrA activity is primarily controlled through sequestration by multiple small regulatory RNAs. Here we investigate CsrA activity control in the absence of antagonizing small RNAs by examining the CsrA regulon in the human pathogen Campylobacter jejuni. We use genome-wide co-immunoprecipitation combined with RNA sequencing to show that CsrA primarily binds flagellar mRNAs and identify the major flagellin mRNA (flaA) as the main CsrA target. The flaA mRNA is translationally repressed by CsrA, but it can also titrate CsrA activity. Together with the main C. jejuni CsrA antagonist, the FliW protein, flaA mRNA controls CsrA-mediated post-transcriptional regulation of other flagellar genes. RNA-FISH reveals that flaA mRNA is expressed and localized at the poles of elongating cells. Polar flaA mRNA localization is translation dependent and is post-transcriptionally regulated by the CsrA-FliW network. Overall, our results suggest a role for CsrA-FliW in spatiotemporal control of flagella assembly and localization of a dual-function mRNA.}, language = {en} } @article{SelleHertleinOesterreichetal.2016, author = {Selle, Martina and Hertlein, Tobias and Oesterreich, Babett and Klemm, Theresa and Kloppot, Peggy and M{\"u}ller, Elke and Ehricht, Ralf and Stentzel, Sebastian and Br{\"o}ker, Barbara M. and Engelmann, Susanne and Ohlsen, Knut}, title = {Global antibody response to Staphylococcus aureus live-cell vaccination}, series = {Scientific Reports}, volume = {6}, journal = {Scientific Reports}, doi = {10.1038/srep24754}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181245}, year = {2016}, abstract = {The pathogen Staphylococcus aureus causes a broad range of severe diseases and is feared for its ability to rapidly develop resistance to antibiotic substances. The increasing number of highly resistant S. aureus infections has accelerated the search for alternative treatment options to close the widening gap in anti-S. aureus therapy. This study analyses the humoral immune response to vaccination of Balb/c mice with sublethal doses of live S. aureus. The elicited antibody pattern in the sera of intravenously and intramuscularly vaccinated mice was determined using of a recently developed protein array. We observed a specific antibody response against a broad set of S. aureus antigens which was stronger following i.v. than i.m. vaccination. Intravenous but not intramuscular vaccination protected mice against an intramuscular challenge infection with a high bacterial dose. Vaccine protection was correlated with the strength of the anti-S. aureus antibody response. This study identified novel vaccine candidates by using protein microarrays as an effective tool and showed that successful vaccination against S. aureus relies on the optimal route of administration.}, language = {en} } @article{EneLohseVladuetal.2016, author = {Ene, Iuliana V. and Lohse, Matthew B. and Vladu, Adrian V. and Morschh{\"a}user, Joachim and Johnson, Alexander D. and Bennett, Richard J.}, title = {Phenotypic Profiling Reveals that Candida albicans Opaque Cells Represent a Metabolically Specialized Cell State Compared to Default White Cells}, series = {mBio}, volume = {7}, journal = {mBio}, number = {6}, doi = {10.1128/mBio.01269-16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165818}, pages = {e01269-16}, year = {2016}, abstract = {The white-opaque switch is a bistable, epigenetic transition affecting multiple traits in Candida albicans including mating, immunogenicity, and niche specificity. To compare how the two cell states respond to external cues, we examined the fitness, phenotypic switching, and filamentation properties of white cells and opaque cells under 1,440 different conditions at 25°C and 37°C. We demonstrate that white and opaque cells display striking differences in their integration of metabolic and thermal cues, so that the two states exhibit optimal fitness under distinct conditions. White cells were fitter than opaque cells under a wide range of environmental conditions, including growth at various pHs and in the presence of chemical stresses or antifungal drugs. This difference was exacerbated at 37°C, consistent with white cells being the default state of C. albicans in the mammalian host. In contrast, opaque cells showed greater fitness than white cells under select nutritional conditions, including growth on diverse peptides at 25°C. We further demonstrate that filamentation is significantly rewired between the two states, with white and opaque cells undergoing filamentous growth in response to distinct external cues. Genetic analysis was used to identify signaling pathways impacting the white-opaque transition both in vitro and in a murine model of commensal colonization, and three sugar sensing pathways are revealed as regulators of the switch. Together, these findings establish that white and opaque cells are programmed for differential integration of metabolic and thermal cues and that opaque cells represent a more metabolically specialized cell state than the default white state.}, language = {en} } @article{BarquistMayhoCumminsetal.2016, author = {Barquist, Lars and Mayho, Matthew and Cummins, Carla and Cain, Amy K. and Boinett, Christine J. and Page, Andrew J. and Langridge, Gemma C. and Quail, Michael A. and Keane, Jacqueline A. and Parkhill, Julian}, title = {The TraDIS toolkit: sequencing and analysis for dense transposon mutant libraries}, series = {Bioinformatics}, volume = {32}, journal = {Bioinformatics}, number = {7}, doi = {10.1093/bioinformatics/btw022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189667}, pages = {1109-1111}, year = {2016}, abstract = {Transposon insertion sequencing is a high-throughput technique for assaying large libraries of otherwise isogenic transposon mutants providing insight into gene essentiality, gene function and genetic interactions. We previously developed the Transposon Directed Insertion Sequencing (TraDIS) protocol for this purpose, which utilizes shearing of genomic DNA followed by specific PCR amplification of transposon-containing fragments and Illumina sequencing. Here we describe an optimized high-yield library preparation and sequencing protocol for TraDIS experiments and a novel software pipeline for analysis of the resulting data. The Bio-Tradis analysis pipeline is implemented as an extensible Perl library which can either be used as is, or as a basis for the development of more advanced analysis tools. This article can serve as a general reference for the application of the TraDIS methodology.}, language = {en} } @article{BlaettnerDasPaprotkaetal.2016, author = {Bl{\"a}ttner, Sebastian and Das, Sudip and Paprotka, Kerstin and Eilers, Ursula and Krischke, Markus and Kretschmer, Dorothee and Remmele, Christian W. and Dittrich, Marcus and M{\"u}ller, Tobias and Schuelein-Voelk, Christina and Hertlein, Tobias and Mueller, Martin J. and Huettel, Bruno and Reinhardt, Richard and Ohlsen, Knut and Rudel, Thomas and Fraunholz, Martin J.}, title = {Staphylococcus aureus Exploits a Non-ribosomal Cyclic Dipeptide to Modulate Survival within Epithelial Cells and Phagocytes}, series = {PLoS Pathogens}, volume = {12}, journal = {PLoS Pathogens}, number = {9}, doi = {10.1371/journal.ppat.1005857}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180380}, year = {2016}, abstract = {Community-acquired (CA) Staphylococcus aureus cause various diseases even in healthy individuals. Enhanced virulence of CA-strains is partly attributed to increased production of toxins such as phenol-soluble modulins (PSM). The pathogen is internalized efficiently by mammalian host cells and intracellular S. aureus has recently been shown to contribute to disease. Upon internalization, cytotoxic S. aureus strains can disrupt phagosomal membranes and kill host cells in a PSM-dependent manner. However, PSM are not sufficient for these processes. Here we screened for factors required for intracellular S. aureus virulence. We infected escape reporter host cells with strains from an established transposon mutant library and detected phagosomal escape rates using automated microscopy. We thereby, among other factors, identified a non-ribosomal peptide synthetase (NRPS) to be required for efficient phagosomal escape and intracellular survival of S. aureus as well as induction of host cell death. By genetic complementation as well as supplementation with the synthetic NRPS product, the cyclic dipeptide phevalin, wild-type phenotypes were restored. We further demonstrate that the NRPS is contributing to virulence in a mouse pneumonia model. Together, our data illustrate a hitherto unrecognized function of the S. aureus NRPS and its dipeptide product during S. aureus infection.}, language = {en} } @article{FroehlichHanekePapenfortetal.2016, author = {Fr{\"o}hlich, Kathrin S. and Haneke, Katharina and Papenfort, Kai and Vogel, J{\"o}rg}, title = {The target spectrum of SdsR small RNA in Salmonella}, series = {Nucleic Acids Research}, volume = {44}, journal = {Nucleic Acids Research}, number = {21}, doi = {10.1093/nar/gkw632}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175365}, pages = {10406-10422}, year = {2016}, abstract = {Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these 'core sRNAs' of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σ\(^{S}\) and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD. However, sdsR genes are present in almost all enterobacterial genomes, suggesting that additional, conserved targets of this sRNA must exist. Here, we have combined SdsR pulse-expression with whole genome transcriptomics to discover 20 previously unknown candidate targets of SdsR which include mRNAs coding for physiologically important regulators such as the carbon utilization regulator, CRP, the nucleoid-associated chaperone, StpA and the antibiotic resistance transporter, TolC. Processing of SdsR by RNase E results in two cellular SdsR variants with distinct target spectra. While the overall physiological role of this orphan core sRNA remains to be fully understood, the new SdsR targets present valuable leads to determine sRNA functions in resting bacteria.}, language = {en} } @article{WheelerBarquistKingsleyetal.2016, author = {Wheeler, Nicole E. and Barquist, Lars and Kingsley, Robert A. and Gardner, Paul P.}, title = {A profile-based method for identifying functional divergence of orthologous genes in bacterial genomes}, series = {Bioinformatics}, volume = {32}, journal = {Bioinformatics}, number = {23}, doi = {10.1093/bioinformatics/btw518}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186502}, pages = {3566-3574}, year = {2016}, abstract = {Motivation: Next generation sequencing technologies have provided us with a wealth of information on genetic variation, but predi cting the functional significance of this variation is a difficult task. While many comparative genomics studies have focused on gene flux and large scale changes, relatively little attention has been paid to quantifying the effects of single nucleotide polymorphisms and indels on protein function, particularly in bacterial genomics. Results: We present a hidden Markov model based approach we call delta-bitscore (DBS) for identifying orthologous proteins that have diverged at the amino acid sequence level in a way that is likely to impact biological function. We benchmark this approach with several widely used datasets and apply it to a proof-of-concept study of orthologous proteomes in an investigation of host adaptation in Salmonella enterica. We highlight the value of the method in identifying functional divergence of genes, and suggest that this tool may be a better approach than the commonly used dN/dS metric for identifying functionally significant genetic changes occurring in recently diverged organisms.}, language = {en} } @article{JiangOronClarketal.2016, author = {Jiang, Yuxiang and Oron, Tal Ronnen and Clark, Wyatt T. and Bankapur, Asma R. and D'Andrea, Daniel and Lepore, Rosalba and Funk, Christopher S. and Kahanda, Indika and Verspoor, Karin M. and Ben-Hur, Asa and Koo, Da Chen Emily and Penfold-Brown, Duncan and Shasha, Dennis and Youngs, Noah and Bonneau, Richard and Lin, Alexandra and Sahraeian, Sayed M. E. and Martelli, Pier Luigi and Profiti, Giuseppe and Casadio, Rita and Cao, Renzhi and Zhong, Zhaolong and Cheng, Jianlin and Altenhoff, Adrian and Skunca, Nives and Dessimoz, Christophe and Dogan, Tunca and Hakala, Kai and Kaewphan, Suwisa and Mehryary, Farrokh and Salakoski, Tapio and Ginter, Filip and Fang, Hai and Smithers, Ben and Oates, Matt and Gough, Julian and T{\"o}r{\"o}nen, Petri and Koskinen, Patrik and Holm, Liisa and Chen, Ching-Tai and Hsu, Wen-Lian and Bryson, Kevin and Cozzetto, Domenico and Minneci, Federico and Jones, David T. and Chapman, Samuel and BKC, Dukka and Khan, Ishita K. and Kihara, Daisuke and Ofer, Dan and Rappoport, Nadav and Stern, Amos and Cibrian-Uhalte, Elena and Denny, Paul and Foulger, Rebecca E. and Hieta, Reija and Legge, Duncan and Lovering, Ruth C. and Magrane, Michele and Melidoni, Anna N. and Mutowo-Meullenet, Prudence and Pichler, Klemens and Shypitsyna, Aleksandra and Li, Biao and Zakeri, Pooya and ElShal, Sarah and Tranchevent, L{\´e}on-Charles and Das, Sayoni and Dawson, Natalie L. and Lee, David and Lees, Jonathan G. and Sillitoe, Ian and Bhat, Prajwal and Nepusz, Tam{\´a}s and Romero, Alfonso E. and Sasidharan, Rajkumar and Yang, Haixuan and Paccanaro, Alberto and Gillis, Jesse and Sede{\~n}o-Cort{\´e}s, Adriana E. and Pavlidis, Paul and Feng, Shou and Cejuela, Juan M. and Goldberg, Tatyana and Hamp, Tobias and Richter, Lothar and Salamov, Asaf and Gabaldon, Toni and Marcet-Houben, Marina and Supek, Fran and Gong, Qingtian and Ning, Wei and Zhou, Yuanpeng and Tian, Weidong and Falda, Marco and Fontana, Paolo and Lavezzo, Enrico and Toppo, Stefano and Ferrari, Carlo and Giollo, Manuel and Piovesan, Damiano and Tosatto, Silvio C. E. and del Pozo, Angela and Fern{\´a}ndez, Jos{\´e} M. and Maietta, Paolo and Valencia, Alfonso and Tress, Michael L. and Benso, Alfredo and Di Carlo, Stefano and Politano, Gianfranco and Savino, Alessandro and Rehman, Hafeez Ur and Re, Matteo and Mesiti, Marco and Valentini, Giorgio and Bargsten, Joachim W. and van Dijk, Aalt D. J. and Gemovic, Branislava and Glisic, Sanja and Perovic, Vladmir and Veljkovic, Veljko and Almeida-e-Silva, Danillo C. and Vencio, Ricardo Z. N. and Sharan, Malvika and Vogel, J{\"o}rg and Kansakar, Lakesh and Zhang, Shanshan and Vucetic, Slobodan and Wang, Zheng and Sternberg, Michael J. E. and Wass, Mark N. and Huntley, Rachael P. and Martin, Maria J. and O'Donovan, Claire and Robinson, Peter N. and Moreau, Yves and Tramontano, Anna and Babbitt, Patricia C. and Brenner, Steven E. and Linial, Michal and Orengo, Christine A. and Rost, Burkhard and Greene, Casey S. and Mooney, Sean D. and Friedberg, Iddo and Radivojac, Predrag and Veljkovic, Nevena}, title = {An expanded evaluation of protein function prediction methods shows an improvement in accuracy}, series = {Genome Biology}, volume = {17}, journal = {Genome Biology}, number = {184}, doi = {10.1186/s13059-016-1037-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166293}, year = {2016}, abstract = {Background A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. Results We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. Conclusions The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent.}, language = {en} }