@article{SunkavalliAguilarSilvaetal.2017, author = {Sunkavalli, Ushasree and Aguilar, Carmen and Silva, Ricardo Jorge and Sharan, Malvika and Cruz, Ana Rita and Tawk, Caroline and Maudet, Claire and Mano, Miguel and Eulalio, Ana}, title = {Analysis of host microRNA function uncovers a role for miR-29b-2-5p in Shigella capture by filopodia}, series = {PLoS Pathogens}, volume = {13}, journal = {PLoS Pathogens}, number = {4}, doi = {10.1371/journal.ppat.1006327}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158204}, pages = {e1006327}, year = {2017}, abstract = {MicroRNAs play an important role in the interplay between bacterial pathogens and host cells, participating as host defense mechanisms, as well as exploited by bacteria to subvert host cellular functions. Here, we show that microRNAs modulate infection by Shigella flexneri, a major causative agent of bacillary dysentery in humans. Specifically, we characterize the dual regulatory role of miR-29b-2-5p during infection, showing that this microRNA strongly favors Shigella infection by promoting both bacterial binding to host cells and intracellular replication. Using a combination of transcriptome analysis and targeted high-content RNAi screening, we identify UNC5C as a direct target of miR-29b-2-5p and show its pivotal role in the modulation of Shigella binding to host cells. MiR-29b-2-5p, through repression of UNC5C, strongly enhances filopodia formation thus increasing Shigella capture and promoting bacterial invasion. The increase of filopodia formation mediated by miR-29b-2-5p is dependent on RhoF and Cdc42 Rho-GTPases. Interestingly, the levels of miR-29b-2-5p, but not of other mature microRNAs from the same precursor, are decreased upon Shigella replication at late times post-infection, through degradation of the mature microRNA by the exonuclease PNPT1. While the relatively high basal levels of miR-29b-2-5p at the start of infection ensure efficient Shigella capture by host cell filopodia, dampening of miR-29b-2-5p levels later during infection may constitute a bacterial strategy to favor a balanced intracellular replication to avoid premature cell death and favor dissemination to neighboring cells, or alternatively, part of the host response to counteract Shigella infection. Overall, these findings reveal a previously unappreciated role of microRNAs, and in particular miR-29b-2-5p, in the interaction of Shigella with host cells.}, language = {en} } @phdthesis{Oesterreich2017, author = {Oesterreich, Babett}, title = {Preclinical development of an immunotherapy against antibiotic-resistant Staphylococcus aureus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123237}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {The Gram-positive bacterium Staphylococcus aureus is the leading cause of nosocomial infections. In particular, diseases caused by methicillin-resistant S. aureus (MRSA) are associated with higher morbidity, mortality and medical costs due to showing resistance to several classes of established antibiotics and their ability to develop resistance mechanisms against new antibiotics rapidly. Therefore, strategies based on immunotherapy approaches have the potential to close the gap for an efficient treatment of MRSA. In this thesis, a humanized antibody specific for the immunodominant staphylococcal antigen A (IsaA) was generated and thoroughly characterized as potential candidate for an antibody based therapy. A murine monoclonal antibody was selected for humanization based on its binding characteristics and the ability of efficient staphylococcal killing in mouse infection models. The murine antibody was humanized by CDR grafting and mouse and humanized scFv as well as scFv-Fc fragments were constructed for comparative binding studies to analyse the successful humanization. After these studies, the full antibody with the complete Fc region was constructed as isotype IgG1, IgG2 and IgG4, respectively to assess effector functions, including antibody-dependent killing of S. aureus. The biological activity of the humanized antibody designated hUK-66 was analysed in vitro with purified human PMNs and whole blood samples taken from healthy donors and patients at high risk of S. aureus infections, such as those with diabetes, end-stage renal disease, or artery occlusive disease (AOD). Results of the in vitro studies show, that hUK-66 was effective in antibody-dependent killing of S. aureus in blood from both healthy controls and patients vulnerable to S. aureus infections. Moreover, the biological activity of hUK-66 and hUK-66 combined with a humanized anti-alpha-toxin antibody (hUK-tox) was investigated in vivo using a mouse pneumonia model. The in vivo results revealed the therapeutic efficacy of hUK-66 and the antibody combination of hUK-66 and hUK-tox to prevent staphylococcal induced pneumonia in a prophylactic set up. Based on the experimental data, hUK-66 represents a promising candidate for an antibody-based therapy against antibiotic resistant MRSA.}, language = {en} } @phdthesis{Sharan2017, author = {Sharan, Malvika}, title = {Bio-computational identification and characterization of RNA-binding proteins in bacteria}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-153573}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {RNA-binding proteins (RBPs) have been extensively studied in eukaryotes, where they post-transcriptionally regulate many cellular events including RNA transport, translation, and stability. Experimental techniques, such as cross-linking and co-purification followed by either mass spectrometry or RNA sequencing has enabled the identification and characterization of RBPs, their conserved RNA-binding domains (RBDs), and the regulatory roles of these proteins on a genome-wide scale. These developments in quantitative, high-resolution, and high-throughput screening techniques have greatly expanded our understanding of RBPs in human and yeast cells. In contrast, our knowledge of number and potential diversity of RBPs in bacteria is comparatively poor, in part due to the technical challenges associated with existing global screening approaches developed in eukaryotes. Genome- and proteome-wide screening approaches performed in silico may circumvent these technical issues to obtain a broad picture of the RNA interactome of bacteria and identify strong RBP candidates for more detailed experimental study. Here, I report APRICOT ("Analyzing Protein RNA Interaction by Combined Output Technique"), a computational pipeline for the sequence-based identification and characterization of candidate RNA-binding proteins encoded in the genomes of all domains of life using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences of an input proteome using position-specific scoring matrices and hidden Markov models of all conserved domains available in the databases and then statistically score them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them according to functionally relevant structural properties. APRICOT performed better than other existing tools for the sequence-based prediction on the known RBP data sets. The applications and adaptability of the software was demonstrated on several large bacterial RBP data sets including the complete proteome of Salmonella Typhimurium strain SL1344. APRICOT reported 1068 Salmonella proteins as RBP candidates, which were subsequently categorized using the RBDs that have been reported in both eukaryotic and bacterial proteins. A set of 131 strong RBP candidates was selected for experimental confirmation and characterization of RNA-binding activity using RNA co-immunoprecipitation followed by high-throughput sequencing (RIP-Seq) experiments. Based on the relative abundance of transcripts across the RIP-Seq libraries, a catalogue of enriched genes was established for each candidate, which shows the RNA-binding potential of 90\% of these proteins. Furthermore, the direct targets of few of these putative RBPs were validated by means of cross-linking and co-immunoprecipitation (CLIP) experiments. This thesis presents the computational pipeline APRICOT for the global screening of protein primary sequences for potential RBPs in bacteria using RBD information from all kingdoms of life. Furthermore, it provides the first bio-computational resource of putative RBPs in Salmonella, which could now be further studied for their biological and regulatory roles. The command line tool and its documentation are available at https://malvikasharan.github.io/APRICOT/.}, language = {en} } @article{HampeFriedmanEdgertonetal.2017, author = {Hampe, Irene A. I. and Friedman, Justin and Edgerton, Mira and Morschh{\"a}user, Joachim}, title = {An acquired mechanism of antifungal drug resistance simultaneously enables Candida albicans to escape from intrinsic host defenses}, series = {PLoS Pathogens}, volume = {13}, journal = {PLoS Pathogens}, number = {9}, doi = {10.1371/journal.ppat.1006655}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158883}, pages = {e1006655}, year = {2017}, abstract = {The opportunistic fungal pathogen Candida albicans frequently produces genetically altered variants to adapt to environmental changes and new host niches in the course of its life-long association with the human host. Gain-of-function mutations in zinc cluster transcription factors, which result in the constitutive upregulation of their target genes, are a common cause of acquired resistance to the widely used antifungal drug fluconazole, especially during long-term therapy of oropharyngeal candidiasis. In this study, we investigated if C. albicans also can develop resistance to the antimicrobial peptide histatin 5, which is secreted in the saliva of humans to protect the oral mucosa from pathogenic microbes. As histatin 5 has been shown to be transported out of C. albicans cells by the Flu1 efflux pump, we screened a library of C. albicans strains that contain artificially activated forms of all zinc cluster transcription factors of this fungus for increased FLU1 expression. We found that a hyperactive Mrr1, which confers fluconazole resistance by upregulating the multidrug efflux pump MDR1 and other genes, also causes FLU1 overexpression. Similarly to the artificially activated Mrr1, naturally occurring gain-of-function mutations in this transcription factor also caused FLU1 upregulation and increased histatin 5 resistance. Surprisingly, however, Mrr1-mediated histatin 5 resistance was mainly caused by the upregulation of MDR1 instead of FLU1, revealing a previously unrecognized function of the Mdr1 efflux pump. Fluconazole-resistant clinical C. albicans isolates with different Mrr1 gain-of-function mutations were less efficiently killed by histatin 5, and this phenotype was reverted when MRR1 was deleted. Therefore, antimycotic therapy can promote the evolution of strains that, as a consequence of drug resistance mutations, simultaneously have acquired increased resistance against an innate host defense mechanism and are thereby better adapted to certain host niches.}, language = {en} } @article{SharanFoerstnerEulalioetal.2017, author = {Sharan, Malvika and F{\"o}rstner, Konrad U. and Eulalio, Ana and Vogel, J{\"o}rg}, title = {APRICOT: an integrated computational pipeline for the sequence-based identification and characterization of RNA-binding proteins}, series = {Nucleic Acids Research}, volume = {45}, journal = {Nucleic Acids Research}, number = {11}, doi = {10.1093/nar/gkx137}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157963}, pages = {e96}, year = {2017}, abstract = {RNA-binding proteins (RBPs) have been established as core components of several post-transcriptional gene regulation mechanisms. Experimental techniques such as cross-linking and co-immunoprecipitation have enabled the identification of RBPs, RNA-binding domains (RBDs) and their regulatory roles in the eukaryotic species such as human and yeast in large-scale. In contrast, our knowledge of the number and potential diversity of RBPs in bacteria is poorer due to the technical challenges associated with the existing global screening approaches. We introduce APRICOT, a computational pipeline for the sequence-based identification and characterization of proteins using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences using position-specific scoring matrices and Hidden Markov Models of the functional domains and statistically scores them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them by several biological properties. Here we demonstrate the application and adaptability of the pipeline on large-scale protein sets, including the bacterial proteome of Escherichia coli. APRICOT showed better performance on various datasets compared to other existing tools for the sequence-based prediction of RBPs by achieving an average sensitivity and specificity of 0.90 and 0.91 respectively. The command-line tool and its documentation are available at https://pypi.python.org/pypi/bio-apricot.}, language = {en} } @article{HeidrichBauriedlBarquistetal.2017, author = {Heidrich, Nadja and Bauriedl, Saskia and Barquist, Lars and Li, Lei and Schoen, Christoph and Vogel, J{\"o}rg}, title = {The primary transcriptome of Neisseria meningitidis and its interaction with the RNA chaperone Hfq}, series = {Nucleic Acids Research}, volume = {45}, journal = {Nucleic Acids Research}, number = {10}, doi = {10.1093/nar/gkx168}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170828}, pages = {6147-6167}, year = {2017}, abstract = {Neisseria meningitidis is a human commensal that can also cause life-threatening meningitis and septicemia. Despite growing evidence for RNA-based regulation in meningococci, their transcriptome structure and output of regulatory small RNAs (sRNAs) are incompletely understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptome of N. meningitidis strain 8013. Annotation of 1625 transcriptional start sites defines transcription units for most protein-coding genes but also reveals a paucity of classical σ70-type promoters, suggesting the existence of activators that compensate for the lack of -35 consensus sequences in N. meningitidis. The transcriptome maps also reveal 65 candidate sRNAs, a third of which were validated by northern blot analysis. Immunoprecipitation with the RNA chaperone Hfq drafts an unexpectedly large post-transcriptional regulatory network in this organism, comprising 23 sRNAs and hundreds of potential mRNA targets. Based on this data, using a newly developed gfp reporter system we validate an Hfq-dependent mRNA repression of the putative colonization factor PrpB by the two trans-acting sRNAs RcoF1/2. Our genome-wide RNA compendium will allow for a better understanding of meningococcal transcriptome organization and riboregulation with implications for colonization of the human nasopharynx.}, 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{TawkSharanEulalioetal.2017, author = {Tawk, Caroline and Sharan, Malvika and Eulalio, Ana and Vogel, J{\"o}rg}, title = {A systematic analysis of the RNA-targeting potential of secreted bacterial effector proteins}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, doi = {10.1038/s41598-017-09527-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158815}, pages = {9328}, year = {2017}, abstract = {Many pathogenic bacteria utilize specialized secretion systems to deliver proteins called effectors into eukaryotic cells for manipulation of host pathways. The vast majority of known effector targets are host proteins, whereas a potential targeting of host nucleic acids remains little explored. There is only one family of effectors known to target DNA directly, and effectors binding host RNA are unknown. Here, we take a two-pronged approach to search for RNA-binding effectors, combining biocomputational prediction of RNA-binding domains (RBDs) in a newly assembled comprehensive dataset of bacterial secreted proteins, and experimental screening for RNA binding in mammalian cells. Only a small subset of effectors were predicted to carry an RBD, indicating that if RNA targeting was common, it would likely involve new types of RBDs. Our experimental evaluation of effectors with predicted RBDs further argues for a general paucity of RNA binding activities amongst bacterial effectors. We obtained evidence that PipB2 and Lpg2844, effector proteins of Salmonella and Legionella species, respectively, may harbor novel biochemical activities. Our study presenting the first systematic evaluation of the RNA-targeting potential of bacterial effectors offers a basis for discussion of whether or not host RNA is a prominent target of secreted bacterial proteins.}, language = {en} } @article{MielichSuessWagnerMietrachetal.2017, author = {Mielich-S{\"u}ss, Benjamin and Wagner, Rabea M. and Mietrach, Nicole and Hertlein, Tobias and Marincola, Gabriella and Ohlsen, Knut and Geibel, Sebastian and Lopez, Daniel}, title = {Flotillin scaffold activity contributes to type VII secretion system assembly in Staphylococcus aureus}, series = {PLoS Pathogens}, volume = {13}, journal = {PLoS Pathogens}, number = {11}, doi = {10.1371/journal.ppat.1006728}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170035}, pages = {e1006728}, year = {2017}, abstract = {Scaffold proteins are ubiquitous chaperones that promote efficient interactions between partners of multi-enzymatic protein complexes; although they are well studied in eukaryotes, their role in prokaryotic systems is poorly understood. Bacterial membranes have functional membrane microdomains (FMM), a structure homologous to eukaryotic lipid rafts. Similar to their eukaryotic counterparts, bacterial FMM harbor a scaffold protein termed flotillin that is thought to promote interactions between proteins spatially confined to the FMM. Here we used biochemical approaches to define the scaffold activity of the flotillin homolog FloA of the human pathogen Staphylococcus aureus, using assembly of interacting protein partners of the type VII secretion system (T7SS) as a case study. Staphylococcus aureus cells that lacked FloA showed reduced T7SS function, and thus reduced secretion of T7SS-related effectors, probably due to the supporting scaffold activity of flotillin. We found that the presence of flotillin mediates intermolecular interactions of T7SS proteins. We tested several small molecules that interfere with flotillin scaffold activity, which perturbed T7SS activity in vitro and in vivo. Our results suggest that flotillin assists in the assembly of S. aureus membrane components that participate in infection and influences the infective potential of this pathogen.}, language = {en} } @article{AshrafYasrebiHertleinetal.2017, author = {Ashraf, Kerolos and Yasrebi, Kaveh and Hertlein, Tobias and Ohlsen, Knut and Lalk, Michael and Hilgeroth, Andreas}, title = {Novel effective small-molecule antibacterials against \(Enterococcus\) strains}, series = {Molecules}, volume = {22}, journal = {Molecules}, number = {12}, doi = {10.3390/molecules22122193}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172628}, year = {2017}, abstract = {\(Enterococcus\) species cause increasing numbers of infections in hospitals. They contribute to the increasing mortality rates, mostly in patients with comorbidities, who suffer from severe diseases. \(Enterococcus\) resistances against most antibiotics have been described, including novel antibiotics. Therefore, there is an ongoing demand for novel types of antibiotics that may overcome bacterial resistances. We discovered a novel class of antibiotics resulting from a simple one-pot reaction of indole and \(o\)-phthaldialdehyde. Differently substituted indolyl benzocarbazoles were yielded. Both the indole substitution and the positioning at the molecular scaffold influence the antibacterial activity towards the various strains of \(Enterococcus\) species with the highest relevance to nosocomial infections. Structure-activity relationships are discussed, and the first lead compounds were identified as also being effective in the case of a vancomycin resistance.}, language = {en} } @phdthesis{Leimbach2017, author = {Leimbach, Andreas}, title = {Genomics of pathogenic and commensal \(Escherichia\) \(coli\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154539}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {High-throughput sequencing (HTS) has revolutionized bacterial genomics. Its unparalleled sensitivity has opened the door to analyzing bacterial evolution and population genomics, dispersion of mobile genetic elements (MGEs), and within-host adaptation of pathogens, such as Escherichia coli. One of the defining characteristics of intestinal pathogenic E. coli (IPEC) pathotypes is a specific repertoire of virulence factors (VFs). Many of these IPEC VFs are used as typing markers in public health laboratories to monitor outbreaks and guide treatment options. Instead, extraintestinal pathogenic E. coli (ExPEC) isolates are genotypically diverse and harbor a varied set of VFs -- the majority of which also function as fitness factors (FFs) for gastrointestinal colonization. The aim of this thesis was the genomic characterization of pathogenic and commensal E. coli with respect to their virulence- and antibiotic resistance-associated gene content as well as phylogenetic background. In order to conduct the comparative analyses, I created a database of E. coli VFs, ecoli_VF_collection, with a focus on ExPEC virulence-associated proteins (Leimbach, 2016b). Furthermore, I wrote a suite of scripts and pipelines, bac-genomics-scripts, that are useful for bacterial genomics (Leimbach, 2016a). This compilation includes tools for assembly and annotation as well as comparative genomics analyses, like multi-locus sequence typing (MLST), assignment of Clusters of Orthologous Groups (COG) categories, searching for protein homologs, detection of genomic regions of difference (RODs), and calculating pan-genome-wide association statistics. Using these tools we were able to determine the prevalence of 18 autotransporters (ATs) in a large, phylogenetically heterogeneous strain panel and demonstrate that many AT proteins are not associated with E. coli pathotypes. According to multivariate analyses and statistics the distribution of AT variants is instead significantly dependent on phylogenetic lineages. As a consequence, ATs are not suitable to serve as pathotype markers (Zude et al., 2014). During the German Shiga toxin-producing E. coli (STEC) outbreak in 2011, the largest to date, we were one of the teams capable of analyzing the genomic features of two isolates. Based on MLST and detection of orthologous proteins to known E. coli reference genomes the close phylogenetic relationship and overall genome similarity to enteroaggregative E. coli (EAEC) 55989 was revealed. In particular, we identified VFs of both STEC and EAEC pathotypes, most importantly the prophage-encoded Shiga toxin (Stx) and the pAA-type plasmid harboring aggregative adherence fimbriae. As a result, we could show that the epidemic was caused by an unusual hybrid pathotype of the O104:H4 serotype. Moreover, we detected the basis of the antibiotic multi-resistant phenotype on an extended-spectrum beta-lactamase (ESBL) plasmid through comparisons to reference plasmids. With this information we proposed an evolutionary horizontal gene transfer (HGT) model for the possible emergence of the pathogen (Brzuszkiewicz et al., 2011). Similarly to ExPEC, E. coli isolates of bovine mastitis are genotypically and phenotypically highly diverse and many studies struggled to determine a positive association of putative VFs. Instead the general E. coli pathogen-associated molecular pattern (PAMP), lipopolysaccharide (LPS), is implicated as a deciding factor for intramammary inflammation. Nevertheless, a mammary pathogenic E. coli (MPEC) pathotype was proposed presumably encompassing strains more adapted to elicit bovine mastitis with virulence traits differentiating them from commensals. We sequenced eight E. coli isolates from udder serous exudate and six fecal commensals (Leimbach et al., 2016). Two mastitis isolate genomes were closed to a finished-grade quality (Leimbach et al., 2015). The genomic sequence of mastitis-associated E. coli (MAEC) strain 1303 was used to elucidate the biosynthesis gene cluster of its O70 LPS O-antigen. We analyzed the phylogenetic genealogy of our strain panel plus eleven bovine-associated E. coli reference strains and found that commensal or MAEC could not be unambiguously allocated to specific phylogroups within a core genome tree of reference E. coli. A thorough gene content analysis could not identify functional convergence of either commensal or MAEC, instead both have only very few gene families enriched in either pathotype. Most importantly, gene content and ecoli_VF_collection analyses showed that no virulence determinants are significantly associated with MAEC in comparison to bovine fecal commensals, disproving the MPEC hypothesis. The genetic repertoire of bovine-associated E. coli, again, is dominated by phylogenetic background. This is also mostly the case for large virulence-associated E. coli gene cluster previously associated with mastitis. Correspondingly, MAEC are facultative and opportunistic pathogens recruited from the bovine commensal gastrointestinal microbiota (Leimbach et al., 2017). Thus, E. coli mastitis should be prevented rather than treated, as antibiotics and vaccines have not proven effective. Although traditional E. coli pathotypes serve a purpose for diagnostics and treatment, it is clear that the current typing system is an oversimplification of E. coli's genomic plasticity. Whole genome sequencing (WGS) revealed many nuances of pathogenic E. coli, including emerging hybrid or heteropathogenic pathotypes. Diagnostic and public health microbiology need to embrace the future by implementing HTS techniques to target patient care and infection control more efficiently.}, subject = {Escherichia coli}, language = {en} } @article{GarciaBetancurGoniMorenoHorgeretal.2017, author = {Garc{\´i}a-Betancur, Juan-Carlos and Go{\~n}i-Moreno, Angel and Horger, Thomas and Schott, Melanie and Sharan, Malvika and Eikmeier, Julian and Wohlmuth, Barbara and Zernecke, Alma and Ohlsen, Knut and Kuttler, Christina and Lopez, Daniel}, title = {Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus}, series = {eLife}, volume = {6}, journal = {eLife}, number = {e28023}, doi = {10.7554/eLife.28023}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170346}, year = {2017}, abstract = {A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types.}, language = {en} } @article{HassanVasquezGuoLiangetal.2017, author = {Hassan, Musa A. and Vasquez, Juan J. and Guo-Liang, Chew and Meissner, Markus and Siegel, T. Nicolai}, title = {Comparative ribosome profiling uncovers a dominant role for translational control in \(Toxoplasma\) \(gondii\)}, series = {BMC Genomics}, volume = {18}, journal = {BMC Genomics}, doi = {10.1186/s12864-017-4362-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172376}, year = {2017}, abstract = {Background The lytic cycle of the protozoan parasite \(Toxoplasma\) \(gondii\), which involves a brief sojourn in the extracellular space, is characterized by defined transcriptional profiles. For an obligate intracellular parasite that is shielded from the cytosolic host immune factors by a parasitophorous vacuole, the brief entry into the extracellular space is likely to exert enormous stress. Due to its role in cellular stress response, we hypothesize that translational control plays an important role in regulating gene expression in \(Toxoplasma\) during the lytic cycle. Unlike transcriptional profiles, insights into genome-wide translational profiles of \(Toxoplasma\) \(gondii\) are lacking. Methods We have performed genome-wide ribosome profiling, coupled with high throughput RNA sequencing, in intracellular and extracellular \(Toxoplasma\) \(gondii\) parasites to investigate translational control during the lytic cycle. Results Although differences in transcript abundance were mostly mirrored at the translational level, we observed significant differences in the abundance of ribosome footprints between the two parasite stages. Furthermore, our data suggest that mRNA translation in the parasite is potentially regulated by mRNA secondary structure and upstream open reading frames. Conclusion We show that most of the \(Toxoplasma\) genes that are dysregulated during the lytic cycle are translationally regulated.}, language = {en} } @article{SchielmannSzwedaGucwaetal.2017, author = {Schielmann, Marta and Szweda, Piotr and Gucwa, Katarzyna and Kawczyński, Marcin and Milewska, Maria J. and Martynow, Dorota and Morschh{\"a}user, Joachim and Milewski, Sławomir}, title = {Transport deficiency is the molecular basis of \(Candida\) \(albicans\) resistance to antifungal oligopeptides}, series = {Frontiers in Microbiology}, volume = {8}, journal = {Frontiers in Microbiology}, doi = {10.3389/fmicb.2017.02154}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173245}, year = {2017}, abstract = {Oligopeptides incorporating \(N3\)-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), an inhibitor of glucosamine-6-phosphate synthase, exhibited growth inhibitory activity against \(Candida\) \(albicans\), with minimal inhibitory concentration values in the 0.05-50 μg mL\(^{-1}\) range. Uptake by the peptide permeases was found to be the main factor limiting an anticandidal activity of these compounds. Di- and tripeptide containing FMDP (F2 and F3) were transported by Ptr2p/Ptr22p peptide transporters (PTR) and FMDP-containing hexa-, hepta-, and undecapeptide (F6, F7, and F11) were taken up by the oligopeptide transporters (OPT) oligopeptide permeases, preferably by Opt2p/Opt3p. A phenotypic, apparent resistance of \(C. albicans\) to FMDP-oligopeptides transported by OPT permeases was triggered by the environmental factors, whereas resistance to those taken up by the PTR system had a genetic basis. Anticandidal activity of longer FMDP-oligopeptides was strongly diminished in minimal media containing easily assimilated ammonium sulfate or L-glutamine as the nitrogen source, both known to downregulate expression of the OPT genes. All FMDP-oligopeptides tested were more active at lower pH and this effect was slightly more remarkable for peptides F6, F7, and F11, compared to F2 and F3. Formation of isolated colonies was observed inside the growth inhibitory zones induced by F2 and F3 but not inside those induced by F6, F7, and F11. The vast majority (98\%) of those colonies did not originate from truly resistant cells. The true resistance of 2\% of isolates was due to the impaired transport of di- and to a lower extent, tripeptides. The resistant cells did not exhibit a lower expression of \(PTR2\), \(PTR22\), or \(OPT1-3\) genes, but mutations in the \(PTR2\) gene resulting in T422H, A320S, D119V, and A320S substitutions in the amino acid sequence of Ptr2p were found.}, language = {en} } @article{BalasubramanianOthmanKampiketal.2017, author = {Balasubramanian, Srikkanth and Othman, Eman M. and Kampik, Daniel and Stopper, Helga and Hentschel, Ute and Ziebuhr, Wilma and Oelschlaeger, Tobias A. and Abdelmohsen, Usama R.}, title = {Marine sponge-derived Streptomyces sp SBT343 extract inhibits staphylococcal biofilm formation}, series = {Frontiers in Microbiology}, volume = {8}, journal = {Frontiers in Microbiology}, doi = {10.3389/fmicb.2017.00236}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171844}, year = {2017}, abstract = {Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to absence of cell toxicity, the extract might represent a good starting material to develop a future remedy to block staphylococcal biofilm formation on contact lenses and thereby to prevent intractable contact lens-mediated ocular infections.}, language = {en} } @article{WestermannBarquistVogel2017, author = {Westermann, Alexander J. and Barquist, Lars and Vogel, J{\"o}rg}, title = {Resolving host-pathogen interactions by dual RNA-seq}, series = {PLoS Pathogens}, volume = {13}, journal = {PLoS Pathogens}, number = {2}, doi = {10.1371/journal.ppat.1006033}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171921}, year = {2017}, abstract = {The transcriptome is a powerful proxy for the physiological state of a cell, healthy or diseased. As a result, transcriptome analysis has become a key tool in understanding the molecular changes that accompany bacterial infections of eukaryotic cells. Until recently, such transcriptomic studies have been technically limited to analyzing mRNA expression changes in either the bacterial pathogen or the infected eukaryotic host cell. However, the increasing sensitivity of high-throughput RNA sequencing now enables "dual RNA-seq" studies, simultaneously capturing all classes of coding and noncoding transcripts in both the pathogen and the host. In the five years since the concept of dual RNA-seq was introduced, the technique has been applied to a range of infection models. This has not only led to a better understanding of the physiological changes in pathogen and host during the course of an infection but has also revealed hidden molecular phenotypes of virulence-associated small noncoding RNAs that were not visible in standard infection assays. Here, we use the knowledge gained from these recent studies to suggest experimental and computational guidelines for the design of future dual RNA-seq studies. We conclude this review by discussing prospective applications of the technique.}, language = {en} } @article{BoehmTorsinTintetal.2017, author = {B{\"o}hm, Lena and Torsin, Sanda and Tint, Su Hlaing and Eckstein, Marie Therese and Ludwig, Tobias and P{\´e}rez, J. Christian}, title = {The yeast form of the fungus Candida albicans promotes persistence in the gut of gnotobiotic mice}, series = {PLoS Pathogens}, volume = {13}, journal = {PLoS Pathogens}, number = {10}, doi = {10.1371/journal.ppat.1006699}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159120}, pages = {e1006699}, year = {2017}, abstract = {Many microorganisms that cause systemic, life-threatening infections in humans reside as harmless commensals in our digestive tract. Yet little is known about the biology of these microbes in the gut. Here, we visualize the interface between the human commensal and pathogenic fungus Candida albicans and the intestine of mice, a surrogate host. Because the indigenous mouse microbiota restricts C. albicans settlement, we compared the patterns of colonization in the gut of germ free and antibiotic-treated conventionally raised mice. In contrast to the heterogeneous morphologies found in the latter, we establish that in germ free animals the fungus almost uniformly adopts the yeast cell form, a proxy of its commensal state. By screening a collection of C. albicans transcription regulator deletion mutants in gnotobiotic mice, we identify several genes previously unknown to contribute to in vivo fitness. We investigate three of these regulators—ZCF8, ZFU2 and TRY4—and show that indeed they favor the yeast form over other morphologies. Consistent with this finding, we demonstrate that genetically inducing non-yeast cell morphologies is detrimental to the fitness of C. albicans in the gut. Furthermore, the identified regulators promote adherence of the fungus to a surface covered with mucin and to mucus-producing intestinal epithelial cells. In agreement with this result, histology sections indicate that C. albicans dwells in the murine gut in close proximity to the mucus layer. Thus, our findings reveal a set of regulators that endows C. albicans with the ability to endure in the intestine through multiple mechanisms.}, 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{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{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} } @phdthesis{HagmanngebKischkies2016, author = {Hagmann [geb. Kischkies], Laura Violetta}, title = {Stringent response regulation and its impact on ex vivo survival in the commensal pathogen \(Neisseria\) \(meningitidis\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-144352}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Neisseria meningitidis is a commensal bacterium which sometimes causes serious disease in humans. Recent studies in numerous human pathogenic bacteria have shown that the stringent response contributes to bacterial virulence. Therefore, this study analyzed the regulation of the stringent response in meningococci and in particular of RelA as well as its contribution to ex vivo fitness in a strain- and condition- dependent manner by using the carriage strain α522 and the hyperinvasive strain MC58 in different in vitro and ex vivo conditions. Growth experiments revealed that both wild-type strains were almost indistinguishable in their ex vivo phenotypes. However, quantitative real time PCR (qRT-PCR) found differences in the gene expression of relA between both strains. Furthermore, in contrast to the MC58 RelA mutant strain α522 deficient in RelA was unable to survive in human whole blood, although both strains showed the same ex vivo phenotypes in saliva and cerebrospinal fluid. Moreover, strain α522 was depended on a short non-coding AT-rich repeat element (ATRrelA) in the promoter region of relA to survive in human blood. Furthermore, cell culture experiments with human epithelial cells revealed that in both strains the deletion of relA resulted in a significantly decreased invasion rate while not significantly affecting adhesion. In order to better understand the conditional lethality of the relA deletion, computational and experimental analyses were carried out to unravel differences in amino acid biosynthetic pathways between both strains. Whereas strain MC58 is able to synthesize all 20 amino acids, strain α522 has an auxotrophy for cysteine and glutamine. In addition, the in vitro growth experiments found that RelA is required for growth in the absence of external amino acids in both strains. Furthermore, the mutant strain MC58 harboring an ATRrelA in its relA promoter region showed improved growth in minimal medium supplemented with L-cysteine and/or L-glutamine compared to the wild-type strain. Contrary, in strain α522 no differences between the wild-type and the ATRrelA deletion mutant were observed. Together this indicates that ATRrelA interferes with the complex regulatory interplay between the stringent response pathway and L-cysteine as well as L-glutamine metabolism. It further suggests that meningococcal virulence is linked to relA in a strain- and condition- depended manner. In conclusion, this work highlighted the role of the stringent response and of non-coding regulatory elements for bacterial virulence and indicates that virulence might be related to the way how meningococci accomplish growth within the host environments.}, subject = {Neisseria meningitidis}, language = {en} } @unpublished{Bartfeld2016, author = {Bartfeld, Sina}, title = {Modeling infectious diseases and host-microbe interactions in gastrointestinal organoids}, series = {Developmental Biology}, journal = {Developmental Biology}, issn = {0012-1606}, doi = {http://dx.doi.org/10.1016/j.ydbio.2016.09.014}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138788}, year = {2016}, abstract = {Advances in stem cell research have allowed the development of 3-dimensional (3D) primary cell cultures termed organoid cultures, as they closely mimic the in vivo organization of different cell lineages. Bridging the gap between 2-dimensional (2D) monotypic cancer cell lines and whole organisms, organoids are now widely applied to model development and disease. Organoids hold immense promise for addressing novel questions in host-microbe interactions, infectious diseases and the resulting inflammatory conditions. Researchers have started to use organoids for modeling infection with pathogens, such as Helicobacter pylori or Salmonella enteritica, gut- microbiota interactions and inflammatory bowel disease. Future studies will broaden the spectrum of microbes used and continue to establish organoids as a standard model for human host-microbial interactions. Moreover, they will increasingly exploit the unique advantages of organoids, for example to address patient-specific responses to microbes.}, 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} } @article{HershkoShalevOdenheimerBergmanElgrablyWeissetal.2016, author = {Hershko-Shalev, Tal and Odenheimer-Bergman, Ahuva and Elgrably-Weiss, Maya and Ben-Zvi, Tamar and Govindarajan, Sutharsan and Seri, Hemda and Papenfort, Kai and Vogel, J{\"o}rg and Altuvia, Shoshy}, title = {Gifsy-1 Prophage IsrK with Dual Function as Small and Messenger RNA Modulates Vital Bacterial Machineries}, series = {PLoS Genetics}, volume = {12}, journal = {PLoS Genetics}, number = {4}, doi = {10.1371/journal.pgen.1005975}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166717}, pages = {e1005975}, year = {2016}, abstract = {While an increasing number of conserved small regulatory RNAs (sRNAs) are known to function in general bacterial physiology, the roles and modes of action of sRNAs from horizontally acquired genomic regions remain little understood. The IsrK sRNA of Gifsy-1 prophage of Salmonella belongs to the latter class. This regulatory RNA exists in two isoforms. The first forms, when a portion of transcripts originating from isrK promoter reads-through the IsrK transcription-terminator producing a translationally inactive mRNA target. Acting in trans, the second isoform, short IsrK RNA, binds the inactive transcript rendering it translationally active. By switching on translation of the first isoform, short IsrK indirectly activates the production of AntQ, an antiterminator protein located upstream of isrK. Expression of antQ globally interferes with transcription termination resulting in bacterial growth arrest and ultimately cell death. Escherichia coli and Salmonella cells expressing AntQ display condensed chromatin morphology and localization of UvrD to the nucleoid. The toxic phenotype of AntQ can be rescued by co-expression of the transcription termination factor, Rho, or RNase H, which protects genomic DNA from breaks by resolving R-loops. We propose that AntQ causes conflicts between transcription and replication machineries and thus promotes DNA damage. The isrK locus represents a unique example of an island-encoded sRNA that exerts a highly complex regulatory mechanism to tune the expression of a toxic protein.}, language = {en} } @article{ReadMillsJohnsonetal.2016, author = {Read, Hannah M. and Mills, Grant and Johnson, Sarah and Tsai, Peter and Dalton, James and Barquist, Lars and Print, Cristin G. and Patrick, Wayne M. and Wiles, Siouxsie}, title = {The in vitro and in vivo effects of constitutive light expression on a bioluminescent strain of the mouse enteropathogen Citrobacter rodentium}, series = {PeerJ}, volume = {4}, journal = {PeerJ}, number = {e2130}, doi = {10.7717/peerj.2130}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166576}, year = {2016}, abstract = {Bioluminescent reporter genes, such as those from fireflies and bacteria, let researchers use light production as a non-invasive and non-destructive surrogate measure of microbial numbers in a wide variety of environments. As bioluminescence needs microbial metabolites, tagging microorganisms with luciferases means only live metabolically active cells are detected. Despite the wide use of bioluminescent reporter genes, very little is known about the impact of continuous (also called constitutive) light expression on tagged bacteria. We have previously made a bioluminescent strain of Citrobacter rodentium, a bacterium which infects laboratory mice in a similar way to how enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC) infect humans. In this study, we compared the growth of the bioluminescent C. rodentium strain ICC180 with its non-bioluminescent parent (strain ICC169) in a wide variety of environments. To understand more about the metabolic burden of expressing light, we also compared the growth profiles of the two strains under approximately 2,000 different conditions. We found that constitutive light expression in ICC180 was near-neutral in almost every non-toxic environment tested. However, we also found that the non-bioluminescent parent strain has a competitive advantage over ICC180 during infection of adult mice, although this was not enough for ICC180 to be completely outcompeted. In conclusion, our data suggest that constitutive light expression is not metabolically costly to C. rodentium and supports the view that bioluminescent versions of microbes can be used as a substitute for their non-bioluminescent parents to study bacterial behaviour in a wide variety of environments.}, language = {en} } @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{BabskiHaasNaetherSchindleretal.2016, author = {Babski, Julia and Haas, Karina A. and N{\"a}ther-Schindler, Daniela and Pfeiffer, Friedhelm and F{\"o}rstner, Konrad U. and Hammelmann, Matthias and Hilker, Rolf and Becker, Anke and Sharma, Cynthia M. and Marchfelder, Anita and Soppa, J{\"o}rg}, title = {Genome-wide identification of transcriptional start sites in the haloarchaeon Haloferax volcanii based on differential RNA-Seq (dRNA-Seq)}, series = {BMC Genomics}, volume = {17}, journal = {BMC Genomics}, number = {629}, doi = {10.1186/s12864-016-2920-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164553}, year = {2016}, abstract = {Background Differential RNA-Seq (dRNA-Seq) is a recently developed method of performing primary transcriptome analyses that allows for the genome-wide mapping of transcriptional start sites (TSSs) and the identification of novel transcripts. Although the transcriptomes of diverse bacterial species have been characterized by dRNA-Seq, the transcriptome analysis of archaeal species is still rather limited. Therefore, we used dRNA-Seq to characterize the primary transcriptome of the model archaeon Haloferax volcanii. Results Three independent cultures of Hfx. volcanii grown under optimal conditions to the mid-exponential growth phase were used to determine the primary transcriptome and map the 5′-ends of the transcripts. In total, 4749 potential TSSs were detected. A position weight matrix (PWM) was derived for the promoter predictions, and the results showed that 64 \% of the TSSs were preceded by stringent or relaxed basal promoters. Of the identified TSSs, 1851 belonged to protein-coding genes. Thus, fewer than half (46 \%) of the 4040 protein-coding genes were expressed under optimal growth conditions. Seventy-two percent of all protein-coding transcripts were leaderless, which emphasized that this pathway is the major pathway for translation initiation in haloarchaea. A total of 2898 of the TSSs belonged to potential non-coding RNAs, which accounted for an unexpectedly high fraction (61 \%) of all transcripts. Most of the non-coding TSSs had not been previously described (2792) and represented novel sequences (59 \% of all TSSs). A large fraction of the potential novel non-coding transcripts were cis-antisense RNAs (1244 aTSSs). A strong negative correlation between the levels of antisense transcripts and cognate sense mRNAs was found, which suggested that the negative regulation of gene expression via antisense RNAs may play an important role in haloarchaea. The other types of novel non-coding transcripts corresponded to internal transcripts overlapping with mRNAs (1153 iTSSs) and intergenic small RNA (sRNA) candidates (395 TSSs). Conclusion This study provides a comprehensive map of the primary transcriptome of Hfx. volcanii grown under optimal conditions. Fewer than half of all protein-coding genes have been transcribed under these conditions. Unexpectedly, more than half of the detected TSSs belonged to several classes of non-coding RNAs. Thus, RNA-based regulation appears to play a more important role in haloarchaea than previously anticipated.}, language = {en} } @article{ČuklinaHahnImakaevetal.2016, author = {Čuklina, Jelena and Hahn, Julia and Imakaev, Maxim and Omasits, Ulrich and F{\"o}rstner, Konrad U. and Ljubimov, Nikolay and Goebel, Melanie and Pessi, Gabriella and Fischer, Hans-Martin and Ahrens, Christian H. and Gelfand, Mikhail S. and Evguenieva-Hackenberg, Elena}, title = {Genome-wide transcription start site mapping of Bradyrhizobium japonicum grown free-living or in symbiosis - a rich resource to identify new transcripts, proteins and to study gene regulation}, series = {BMC Genomics}, volume = {17}, journal = {BMC Genomics}, doi = {10.1186/s12864-016-2602-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164565}, pages = {302}, year = {2016}, abstract = {Background Differential RNA-sequencing (dRNA-seq) is indispensable for determination of primary transcriptomes. However, using dRNA-seq data to map transcriptional start sites (TSSs) and promoters genome-wide is a bioinformatics challenge. We performed dRNA-seq of Bradyrhizobium japonicum USDA 110, the nitrogen-fixing symbiont of soybean, and developed algorithms to map TSSs and promoters. Results A specialized machine learning procedure for TSS recognition allowed us to map 15,923 TSSs: 14,360 in free-living bacteria, 4329 in symbiosis with soybean and 2766 in both conditions. Further, we provide proteomic evidence for 4090 proteins, among them 107 proteins corresponding to new genes and 178 proteins with N-termini different from the existing annotation (72 and 109 of them with TSS support, respectively). Guided by proteomics evidence, previously identified TSSs and TSSs experimentally validated here, we assign a score threshold to flag 14 \% of the mapped TSSs as a class of lower confidence. However, this class of lower confidence contains valid TSSs of low-abundant transcripts. Moreover, we developed a de novo algorithm to identify promoter motifs upstream of mapped TSSs, which is publicly available, and found motifs mainly used in symbiosis (similar to RpoN-dependent promoters) or under both conditions (similar to RpoD-dependent promoters). Mapped TSSs and putative promoters, proteomic evidence and updated gene annotation were combined into an annotation file. Conclusions The genome-wide TSS and promoter maps along with the extended genome annotation of B. japonicum represent a valuable resource for future systems biology studies and for detailed analyses of individual non-coding transcripts and ORFs. Our data will also provide new insights into bacterial gene regulation during the agriculturally important symbiosis between rhizobia and legumes.}, 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{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{MuellerDolowschiakSellinetal.2016, author = {M{\"u}ller, Anna A. and Dolowschiak, Tamas and Sellin, Mikael E. and Felmy, Boas and Verbree, Carolin and Gadient, Sandra and Westermann, Alexander J. and Vogel, J{\"o}rg and LeibundGut-Landmann, Salome and Hardt, Wolf-Dietrich}, title = {An NK Cell Perforin Response Elicited via IL-18 Controls Mucosal Inflammation Kinetics during Salmonella Gut Infection}, series = {PLoS Pathogens}, volume = {12}, journal = {PLoS Pathogens}, number = {6}, doi = {10.1371/journal.ppat.1005723}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167429}, pages = {e1005723}, year = {2016}, abstract = {Salmonella Typhimurium (S.Tm) is a common cause of self-limiting diarrhea. The mucosal inflammation is thought to arise from a standoff between the pathogen's virulence factors and the host's mucosal innate immune defenses, particularly the mucosal NAIP/NLRC4 inflammasome. However, it had remained unclear how this switches the gut from homeostasis to inflammation. This was studied using the streptomycin mouse model. S.Tm infections in knockout mice, cytokine inhibition and -injection experiments revealed that caspase-1 (not -11) dependent IL-18 is pivotal for inducing acute inflammation. IL-18 boosted NK cell chemoattractants and enhanced the NK cells' migratory capacity, thus promoting mucosal accumulation of mature, activated NK cells. NK cell depletion and Prf\(^{-/-}\) ablation (but not granulocyte-depletion or T-cell deficiency) delayed tissue inflammation. Our data suggest an NK cell perforin response as one limiting factor in mounting gut mucosal inflammation. Thus, IL-18-elicited NK cell perforin responses seem to be critical for coordinating mucosal inflammation during early infection, when S.Tm strongly relies on virulence factors detectable by the inflammasome. This may have broad relevance for mucosal defense against microbial pathogens.}, 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{EspinaPaganLopezetal.2015, author = {Espina, Laura and Pag{\´a}n, Rafael and L{\´o}pez, Daniel and Garc{\´i}a-Gonzalo, Diego}, title = {Individual Constituents from Essential Oils Inhibit Biofilm Mass Production by Multi-Drug Resistant Staphylococcus aureus}, series = {Molecules}, volume = {20}, journal = {Molecules}, doi = {10.3390/molecules200611357}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151845}, pages = {11357 -- 11372}, year = {2015}, abstract = {Biofilm formation by Staphylococcus aureus represents a problem in both the medical field and the food industry, because the biofilm structure provides protection to embedded cells and it strongly attaches to surfaces. This circumstance is leading to many research programs seeking new alternatives to control biofilm formation by this pathogen. In this study we show that a potent inhibition of biofilm mass production can be achieved in community-associated methicillin-resistant S. aureus (CA-MRSA) and methicillin-sensitive strains using plant compounds, such as individual constituents (ICs) of essential oils (carvacrol, citral, and (+)-limonene). The Crystal Violet staining technique was used to evaluate biofilm mass formation during 40 h of incubation. Carvacrol is the most effective IC, abrogating biofilm formation in all strains tested, while CA-MRSA was the most sensitive phenotype to any of the ICs tested. Inhibition of planktonic cells by ICs during initial growth stages could partially explain the inhibition of biofilm formation. Overall, our results show the potential of EOs to prevent biofilm formation, especially in strains that exhibit resistance to other antimicrobials. As these compounds are food additives generally recognized as safe, their anti-biofilm properties may lead to important new applications, such as sanitizers, in the food industry or in clinical settings.}, language = {en} } @article{FirdessaGoodAmstaldenetal.2015, author = {Firdessa, Rebuma and Good, Liam and Amstalden, Maria Cecilia and Chindera, Kantaraja and Kamaruzzaman, Nor Fadhilah and Schultheis, Martina and R{\"o}ger, Bianca and Hecht, Nina and Oelschlaeger, Tobias A. and Meinel, Lorenz and L{\"u}hmann, Tessa and Moll, Heidrun}, title = {Pathogen- and host-directed antileishmanial effects mediated by polyhexanide (PHMB)}, series = {PLoS Neglected Tropical Diseases}, volume = {9}, journal = {PLoS Neglected Tropical Diseases}, number = {10}, doi = {10.1371/journal.pntd.0004041}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148162}, pages = {e0004041}, year = {2015}, abstract = {Background Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed. Methodology/Principal Findings Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide), a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major) via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN). PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB. Conclusions Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators.}, language = {en} } @article{DembekBarquistBoinettetal.2015, author = {Dembek, Marcin and Barquist, Lars and Boinett, Christine J. and Cain, Amy K. and Mayho, Matthew and Lawley, Trevor D. and Fairweather, Neil F. and Fagan, Robert P.}, title = {High-throughput analysis of gene essentiality and sporulation in Clostridium difficile}, series = {mBio}, volume = {6}, journal = {mBio}, number = {2}, doi = {10.1128/mBio.02383-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143745}, pages = {e02383-14}, year = {2015}, abstract = {Clostridium difficile is the most common cause of antibiotic-associated intestinal infections and a significant cause of morbidity and mortality. Infection with C. difficile requires disruption of the intestinal microbiota, most commonly by antibiotic usage. Therapeutic intervention largely relies on a small number of broad-spectrum antibiotics, which further exacerbate intestinal dysbiosis and leave the patient acutely sensitive to reinfection. Development of novel targeted therapeutic interventions will require a detailed knowledge of essential cellular processes, which represent attractive targets, and species-specific processes, such as bacterial sporulation. Our knowledge of the genetic basis of C. difficile infection has been hampered by a lack of genetic tools, although recent developments have made some headway in addressing this limitation. Here we describe the development of a method for rapidly generating large numbers of transposon mutants in clinically important strains of C. difficile. We validated our transposon mutagenesis approach in a model strain of C. difficile and then generated a comprehensive transposon library in the highly virulent epidemic strain R20291 (027/BI/NAP1) containing more than 70,000 unique mutants. Using transposon-directed insertion site sequencing (TraDIS), we have identified a core set of 404 essential genes, required for growth in vitro. We then applied this technique to the process of sporulation, an absolute requirement for C. difficile transmission and pathogenesis, identifying 798 genes that are likely to impact spore production. The data generated in this study will form a valuable resource for the community and inform future research on this important human pathogen.}, language = {en} } @phdthesis{Sturm2015, author = {Sturm, Volker J{\"o}rg Friedrich}, title = {\(^{19}F\) Magnetresonanztomographie zur Bildgebung von Infektionen im Zeitverlauf}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-122851}, school = {Universit{\"a}t W{\"u}rzburg}, pages = {114}, year = {2015}, abstract = {Im Rahmen dieser Arbeit sollten die M{\"o}glichkeiten der MR Tomographie erkundet werden bakterielle Infektionen im Zeitverlauf darzustellen. Genauer gesagt sollte das Potential der MR Tomographie anhand eines durch eine Infektion induzierten lokalisierten Abszesses unter Verwendung dreier unterschiedlicher MRT Methoden untersucht werden: Mittels nativem \(T_2\) Kontrast; der Verwendung von superparamagnetischen Eisenoxid Partieln (USPIO) als \(T_2^*\) Kontrastmittel; und dem Einsatz von Perfluorkarbonen (PFC) als \(^{19}F\) MRT Marker (siehe Kapitel 3). Wie erwartet f{\"u}hrte die durch die Infektion hervorgerufene Entz{\"u}ndung zu ver{\"a}nderten \(T_2\)-Zeiten, welche auf \(T_2\)-gewichteten MR Bildern eine Lokalisierung des Abszessbereiches erlauben. Jedoch eigneten sich diese Daten aufgrund der graduellen {\"A}nderung der \(T_2\)-Zeiten nicht, um eine klare Grenze zwischen Abszess und umliegendem Gewebe zu ziehen. Superparamagnetische Eisenoxidpartikel andererseit haben als MRT Kontrastmittel bereits in den letzten Jahren ihre F{\"a}higkeit unter Beweis gestellt Entz{\"u}ndungen [53, 58, 64] darzustellen. Die Anreicherung dieser Partikel am Rande des Abszesses [53], wie sie auch in unseren MR Daten zu beobachten war, erlaubte eine relativ scharfe Abgrenzung gegen{\"u}ber dem umgebenden Gewebe in der chronischen Phase der Infektion (Tag 9 p.i.). Hingegen gen{\"u}gte die nur sehr sp{\"a}rlichen Anreicherung von USPIO Partikeln in der akuten Phase der Infektion (Tag 3 p.i.) nicht f{\"u}r eine entsprechende Abgrenzung [58]. Aufgrund der sehr geringen biologischen H{\"a}ufigkeit und den sehr kurzen Relaxationszeiten von endogenem Fluor eignen sich Perfluorkarbone als Markersubstanz in der MR Tomographie von biologischen Systemen. Insbesondere da PFC Emulsionen durch phagozytierende Zellen aufgenommen werden und im Bereich von Entz{\"u}ndungen akkumulieren [30, 59]. In dieser Arbeit konnte anhand der erhaltenen MRT Daten eine Akkumulation von Perfluorkarbonen nicht nur in der chronischen Phase, sondern auch in der akuten Phase nachgewiesen werden. Diese Daten erlauben somit zu allen untersuchten Zeitpunkten eine Abgrenzung zwischen Infektion und umliegenden Gewebe. Aufgrund der besagten Vorteile wurden die Perfluorkarbone gew{\"a}hlt, um die M{\"o}glichkeiten der MR Tomographie zu testen, quantitative Informationen {\"u}ber die schwere der Infektion zu liefern. Als Referenz f{\"u}r die Bakterienbelastung wurden die Biolumineszenzbildgebung (BLI) [49, 50] und die Standardmethode zur Bestimmung der Bakterienbelastung cfu (koloniebildenden Einheiten) herangezogen. Eine Gegen{\"u}berstellung der zeitlichen Verl{\"a}ufe der durch die Biolumineszenzbildgebung und durch die cfu erhaltenen Daten liefert eine qualitative {\"U}bereinstimmung mit den durch die 19F MR Tomographie erhaltenen Daten. Dies trifft hierbei sowohl auf die {\"u}ber den gesamten Infektionsbereich hinweg summierten Signalamplituden, als auch auf das Volumen zu, in dem Fluor am Ort der Infektion akkumuliert wurde. Im Gegensatz zur Methode der cfu Bestimmung sind die MR Tomographie und die Biolumineszenzbildgebung nicht invasiv und erlauben die Verfolgung des Infektionsverlaufes an einem einzelnen Individuum. Hierzu ben{\"o}tigt, im Gegensatz zur MR Tomographie, die Methode der Biolumineszenzbildgebung jedoch einen speziellen Pathogenstamm. Dar{\"u}ber hinaus ist hervorzuheben, dass die MR Tomographie zudem die M{\"o}glichkeit bietet auch morphologische Informationen {\"u}ber den Infektionsbereich und seine Umgebung zu akquirieren. Gerade weil jede dieser Methoden die mit der Infektion einhergehenden Prozesse aus einer leicht anderen Blickrichtung betrachtet, erscheint es sinnvoll diese etablierte Untersuchungsplattform bestehend aus MRT, BLI und cfu {\"u}ber die in dieser Arbeit bearbeitete Fragestellung hinaus n{\"a}her zu untersuchen. Insbesondere der Aspekt inwieweit die drei Methoden sich gegenseitig erg{\"a}nzen, k{\"o}nnte einen tieferen Einblick in die Wechselwirkung zwischen Pathogen und Wirt erlauben. Auch wenn f{\"u}r die betrachtete Fragestellung bereits der hierdurchgef{\"u}hrte semiquanitative Ansatz zur Bestimmung der relativen Fluormengen am Ort der Infektion ausreichte, so ist doch im Allgemeinen w{\"u}nschenswert probenbezogen die Sensitivit{\"a}t der Spule und damit die G{\"u}te der Spulenabstimmung zu bestimmen. Hierzu ist jedoch die Aufnahme von \(B_1\)-Karten unabdingbar und wird entsprechend im Kapitel 4 \(Bloch-Siegert B_1^+-Mapping\) n{\"a}her addressiert. Der Schwerpunkt liegt hierbei, wie der Kapitelname bereits andeutet, auf der Bloch-Siegert Methode, die insbesondere in der pr{\"a}sentierten Implementierung in einer Turbo/ Multi Spin Echo Sequenz eine effiziente Nutzung der relativ langen \(T_\)2-Zeiten der Perfluorkarbone erlaubt. Da zudem die Bloch-Siegert-Methode eine rein phasenbasierte Methode ist, kann neben der aus den Daten erzeugten \(B_1\)-Karte zugleich ein unverf{\"a}lschtes Magnitudenbild generiert werden, wodurch eine sehr effiziente Nutzung der vorhandenen Messzeit erm{\"o}glicht wird. Diese Eigenschaft ist insbesondere f{\"u}r \(^{19}F\) Bildgebung von besonderem Interesse, da hier f{\"u}r jede Messung, aufgrund der {\"u}blicherweise relativ geringen Konzentration an Fluoratomen, lange Messzeiten ben{\"o}tigt werden. Zusammenfassend konnte anhand des untersuchten Tiermodells sowohl die F{\"a}higkeit der MR Tomographie nachgewiesen werden Infektionen im Zeitverlauf darzustellen, als auch die F{\"a}higkeit der MR Tomographie quantitative Informationen {\"u}ber den Verlauf der Infektion zu liefern. Desweiteren konnte eine M{\"o}glichkeit aufgezeigt werden, welche das Potential hat in vertretbarem Zeitrahmen auch in vivo B1+-Karten auf dem Fluorkanal zu erstellen und so einen zentralen Unsicherheitsfaktor, f{\"u}r Relaxometry und absolute Quantifizierung von \(^{19}F\) Daten in vivo, zu beseitigen.}, subject = {Kernspintomografie}, language = {de} } @article{NeumannOhlsenDonatetal.2015, author = {Neumann, Yvonne and Ohlsen, Knut and Donat, Stefanie and Engelmann, Susanne and Kusch, Harald and Albrecht, Dirk and Cartron, Michael and Hurd, Alexander and Foster, Simon J.}, title = {The effect of skin fatty acids on Staphylococcus aureus}, series = {Archives of Microbiology}, volume = {197}, journal = {Archives of Microbiology}, doi = {10.1007/s00203-014-1048-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121657}, pages = {245-67}, year = {2015}, abstract = {Staphylococcus aureus is a commensal of the human nose and skin. Human skin fatty acids, in particular cis-6-hexadecenoic acid (C-6-H), have high antistaphylococcal activity and can inhibit virulence determinant production. Here, we show that sub-MIC levels of C-6-H result in induction of increased resistance. The mechanism(s) of C-6-H activity was investigated by combined transcriptome and proteome analyses. Proteome analysis demonstrated a pleiotropic effect of C-6-H on virulence determinant production. In response to C-6-H, transcriptomics revealed altered expression of over 500 genes, involved in many aspects of virulence and cellular physiology. The expression of toxins (hla, hlb, hlgBC) was reduced, whereas that of host defence evasion components (cap, sspAB, katA) was increased. In particular, members of the SaeRS regulon had highly reduced expression, and the use of specific mutants revealed that the effect on toxin production is likely mediated via SaeRS}, language = {en} } @article{MasicValenciaHernandezHazraetal.2015, author = {Masic, Anita and Valencia Hernandez, Ana Maria and Hazra, Sudipta and Glaser, Jan and Holzgrabe, Ulrike and Hazra, Banasri and Schurigt, Uta}, title = {Cinnamic Acid Bornyl Ester Derivatives from Valeriana wallichii Exhibit Antileishmanial In Vivo Activity in Leishmania major-Infected BALB/c Mice}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {11}, doi = {10.1371/journal.pone.0142386}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125354}, pages = {e0142386}, year = {2015}, abstract = {Human leishmaniasis covers a broad spectrum of clinical manifestations ranging from self-healing cutaneous leishmaniasis to severe and lethal visceral leishmaniasis caused among other species by Leishmania major or Leishmania donovani, respectively. Some drug candidates are in clinical trials to substitute current therapies, which are facing emerging drug-resistance accompanied with serious side effects. Here, two cinnamic acid bornyl ester derivatives (1 and 2) were assessed for their antileishmanial activity. Good selectivity and antileishmanial activity of bornyl 3-phenylpropanoate (2) in vitro prompted the antileishmanial assessment in vivo. For this purpose, BALB/c mice were infected with Leishmania major promastigotes and treated with three doses of 50 mg/kg/day of compound 2. The treatment prevented the characteristic swelling at the site of infection and correlated with reduced parasite burden. Transmitted light microscopy and transmission electron microscopy of Leishmania major promastigotes revealed that compounds 1 and 2 induce mitochondrial swelling. Subsequent studies on Leishmania major promastigotes showed the loss of mitochondrial transmembrane potential (ΔΨm) as a putative mode of action. As the cinnamic acid bornyl ester derivatives 1 and 2 had exhibited antileishmanial activity in vitro, and compound 2 in Leishmania major-infected BALB/c mice in vivo, they can be regarded as possible lead structures for the development of new antileishmanial therapeutic approaches.}, language = {en} } @article{SchneiderKleinMielichSuessetal.2015, author = {Schneider, Johannes and Klein, Teresa and Mielich-S{\"u}ss, Benjamin and Koch, Gudrun and Franke, Christian and Kuipers, Oskar P. and Kov{\´a}cs, {\´A}kos T. and Sauer, Markus and Lopez, Daniel}, title = {Spatio-temporal Remodeling of Functional Membrane Microdomains Organizes the Signaling Networks of a Bacterium}, series = {PLoS Genetics}, volume = {11}, journal = {PLoS Genetics}, number = {4}, doi = {10.1371/journal.pgen.1005140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125577}, pages = {e1005140}, year = {2015}, abstract = {Lipid rafts are membrane microdomains specialized in the regulation of numerous cellular processes related to membrane organization, as diverse as signal transduction, protein sorting, membrane trafficking or pathogen invasion. It has been proposed that this functional diversity would require a heterogeneous population of raft domains with varying compositions. However, a mechanism for such diversification is not known. We recently discovered that bacterial membranes organize their signal transduction pathways in functional membrane microdomains (FMMs) that are structurally and functionally similar to the eukaryotic lipid rafts. In this report, we took advantage of the tractability of the prokaryotic model Bacillus subtilis to provide evidence for the coexistence of two distinct families of FMMs in bacterial membranes, displaying a distinctive distribution of proteins specialized in different biological processes. One family of microdomains harbors the scaffolding flotillin protein FloA that selectively tethers proteins specialized in regulating cell envelope turnover and primary metabolism. A second population of microdomains containing the two scaffolding flotillins, FloA and FloT, arises exclusively at later stages of cell growth and specializes in adaptation of cells to stationary phase. Importantly, the diversification of membrane microdomains does not occur arbitrarily. We discovered that bacterial cells control the spatio-temporal remodeling of microdomains by restricting the activation of FloT expression to stationary phase. This regulation ensures a sequential assembly of functionally specialized membrane microdomains to strategically organize signaling networks at the right time during the lifespan of a bacterium.}, language = {en} } @article{GlaserSchurigtSuzukietal.2015, author = {Glaser, Jan and Schurigt, Uta and Suzuki, Brian M. and Caffrey, Connor R. and Holzgrabe, Ulrike}, title = {Anti-Schistosomal Activity of Cinnamic Acid Esters: Eugenyl}, series = {Molecules}, volume = {20}, journal = {Molecules}, doi = {10.3390/molecules200610873}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125712}, pages = {10873-10883}, year = {2015}, abstract = {Bornyl caffeate (1) was previously isolated by us from Valeriana (V.) wallichii rhizomes and identified as an anti-leishmanial substance. Here, we screened a small compound library of synthesized derivatives 1-30 for activity against schistosomula of Schistosoma (S.) mansoni. Compound 1 did not show any anti-schistosomal activity. However, strong phenotypic changes, including the formation of vacuoles, degeneration and death were observed after in vitro treatment with compounds 23 (thymyl cinnamate) and 27 (eugenyl cinnamate). Electron microscopy analysis of the induced vacuoles in the dying parasites suggests that 23 and 27 interfere with autophagy.}, language = {en} } @article{FrankMarcudeOliveiraAlmeidaPetersenetal.2015, author = {Frank, Benjamin and Marcu, Ana and de Oliveira Almeida Petersen, Antonio Luis and Weber, Heike and Stigloher, Christian and Mottram, Jeremy C. and Scholz, Claus J{\"u}rgen and Schurigt, Uta}, title = {Autophagic digestion of Leishmania major by host macrophages is associated with differential expression of BNIP3, CTSE, and the miRNAs miR-101c, miR-129, and miR-210}, series = {Parasites \& Vectors}, volume = {8}, journal = {Parasites \& Vectors}, number = {404}, doi = {10.1186/s13071-015-0974-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-124997}, year = {2015}, abstract = {Background Autophagy participates in innate immunity by eliminating intracellular pathogens. Consequently, numerous microorganisms have developed strategies to impair the autophagic machinery in phagocytes. In the current study, interactions between Leishmania major (L. m.) and the autophagic machinery of bone marrow-derived macrophages (BMDM) were analyzed. Methods BMDM were generated from BALB/c mice, and the cells were infected with L. m. promastigotes. Transmission electron microscopy (TEM) and electron tomography were used to investigate the ultrastructure of BMDM and the intracellular parasites. Affymetrix® chip analyses were conducted to identify autophagy-related messenger RNAs (mRNAs) and microRNAs (miRNAs). The protein expression levels of autophagy related 5 (ATG5), BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), cathepsin E (CTSE), mechanistic target of rapamycin (MTOR), microtubule-associated proteins 1A/1B light chain 3B (LC3B), and ubiquitin (UB) were investigated through western blot analyses. BMDM were transfected with specific small interfering RNAs (siRNAs) against autophagy-related genes and with mimics or inhibitors of autophagy-associated miRNAs. The infection rates of BMDM were determined by light microscopy after a parasite-specific staining. Results The experiments demonstrated autophagy induction in BMDM after in vitro infection with L. m.. The results suggested a putative MTOR phosphorylation-dependent counteracting mechanism in the early infection phase and indicated that intracellular amastigotes were cleared by autophagy in BMDM in the late infection phase. Transcriptomic analyses and specific downregulation of protein expression with siRNAs suggested there is an association between the infection-specific over expression of BNIP3, as well as CTSE, and the autophagic activity of BMDM. Transfection with mimics of mmu-miR-101c and mmu-miR-129-5p, as well as with an inhibitor of mmu-miR-210-5p, demonstrated direct effects of the respective miRNAs on parasite clearance in L. m.-infected BMDM. Furthermore, Affymetrix® chip analyses revealed a complex autophagy-related RNA network consisting of differentially expressed mRNAs and miRNAs in BMDM, which indicates high glycolytic and inflammatory activity in the host macrophages. Conclusions Autophagy in L. m.-infected host macrophages is a highly regulated cellular process at both the RNA level and the protein level. Autophagy has the potential to clear parasites from the host. The results obtained from experiments with murine host macrophages could be translated in the future to develop innovative and therapeutic antileishmanial strategies for human patients.}, 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{vonBohlKuehnSimonetal.2015, author = {von Bohl, Andreas and Kuehn, Andrea and Simon, Nina and Nkwouano Ngongang, Vanesa and Spehr, Marc and Baumeister, Stefan and Przyborski, Jude M. and Fischer, Rainer and Pradel, Gabriele}, title = {A WD40-repeat protein unique to malaria parasites associates with adhesion protein complexes and is crucial for blood stage progeny}, series = {Malaria Journal}, volume = {14}, journal = {Malaria Journal}, number = {435}, doi = {10.1186/s12936-015-0967-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139728}, year = {2015}, abstract = {Background During development in human erythrocytes, Plasmodium falciparum parasites display a remarkable number of adhesive proteins on their plasma membrane. In the invasive merozoites, these include members of the PfMSP1 and PfAMA1/RON complexes, which facilitate contact between merozoites and red blood cells. In gametocytes, sexual precursor cells mediating parasite transmission to the mosquito vector, plasma membrane-associated proteins primarily belong to the PfCCp and 6-cys families with roles in fertilization. This study describes a newly identified WD40-repeat protein unique to Plasmodium species that associates with adhesion protein complexes of both merozoites and gametocytes. Methods The WD40-repeat protein-like protein PfWLP1 was identified via co-immunoprecipitation assays followed by mass spectrometry and characterized using biochemical and immunohistochemistry methods. Reverse genetics were employed for functional analysis. Results PfWLP1 is expressed both in schizonts and gametocytes. In mature schizonts, the protein localizes underneath the merozoite micronemes and interacts with PfAMA1, while in gametocytes PfWLP1 primarily accumulates underneath the plasma membrane and associates with PfCCp1 and Pfs230. Reverse genetics failed to disrupt the pfwlp1 gene, while haemagglutinin-tagging was feasible, suggesting a crucial function for PfWLP1 during blood stage replication. Conclusions This is the first report on a plasmodial WD40-repeat protein associating with cell adhesion proteins. Since WD40 domains are known to mediate protein-protein contact by serving as a rigid scaffold for protein interactions, the presented data suggest that PfWLP1 supports the stability of adhesion protein complexes of the plasmodial blood stages.}, language = {en} } @article{SassVanAckerFoerstneretal.2015, author = {Sass, Andrea M. and Van Acker, Heleen and F{\"o}rstner, Konrad U. and Van Nieuwerburgh, Filip and Deforce, Dieter and Vogel, J{\"o}rg and Coenye, Tom}, title = {Genome-wide transcription start site profiling in biofilm-grown Burkholderia cenocepacia J2315}, series = {BMC Genomics}, volume = {16}, journal = {BMC Genomics}, number = {775}, doi = {10.1186/s12864-015-1993-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139748}, year = {2015}, abstract = {Background: Burkholderia cenocepacia is a soil-dwelling Gram-negative Betaproteobacterium with an important role as opportunistic pathogen in humans. Infections with B. cenocepacia are very difficult to treat due to their high intrinsic resistance to most antibiotics. Biofilm formation further adds to their antibiotic resistance. B. cenocepacia harbours a large, multi-replicon genome with a high GC-content, the reference genome of strain J2315 includes 7374 annotated genes. This study aims to annotate transcription start sites and identify novel transcripts on a whole genome scale. Methods: RNA extracted from B. cenocepacia J2315 biofilms was analysed by differential RNA-sequencing and the resulting dataset compared to data derived from conventional, global RNA-sequencing. Transcription start sites were annotated and further analysed according to their position relative to annotated genes. Results: Four thousand ten transcription start sites were mapped over the whole B. cenocepacia genome and the primary transcription start site of 2089 genes expressed in B. cenocepacia biofilms were defined. For 64 genes a start codon alternative to the annotated one was proposed. Substantial antisense transcription for 105 genes and two novel protein coding sequences were identified. The distribution of internal transcription start sites can be used to identify genomic islands in B. cenocepacia. A potassium pump strongly induced only under biofilm conditions was found and 15 non-coding small RNAs highly expressed in biofilms were discovered. Conclusions: Mapping transcription start sites across the B. cenocepacia genome added relevant information to the J2315 annotation. Genes and novel regulatory RNAs putatively involved in B. cenocepacia biofilm formation were identified. These findings will help in understanding regulation of B. cenocepacia biofilm formation.}, language = {en} } @article{FanLiChaoetal.2015, author = {Fan, Ben and Li, Lei and Chao, Yanjie and F{\"o}rstner, Konrad and Vogel, J{\"o}rg and Borriss, Rainer and Wu, Xiao-Qin}, title = {dRNA-Seq Reveals Genomewide TSSs and Noncoding RNAs of Plant Beneficial Rhizobacterium Bacillus amyloliquefaciens FZB42}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {11}, doi = {10.1371/journal.pone.0142002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138369}, pages = {e0142002}, year = {2015}, abstract = {Bacillus amyloliquefaciens subsp. plantarum FZB42 is a representative of Gram-positive plant-growth-promoting rhizobacteria (PGPR) that inhabit plant root environments. In order to better understand the molecular mechanisms of bacteria-plant symbiosis, we have systematically analyzed the primary transcriptome of strain FZB42 grown under rhizospheremimicking conditions using differential RNA sequencing (dRNA-seq). Our analysis revealed 4,877 transcription start sites for protein-coding genes, identified genes differentially expressed under different growth conditions, and corrected many previously mis-annotated genes. We also identified a large number of riboswitches and cis-encoded antisense RNAs, as well as trans-encoded small noncoding RNAs that may play important roles in the gene regulation of Bacillus. Overall, our analyses provided a landscape of Bacillus primary transcriptome and improved the knowledge of rhizobacteria-host interactions.}, language = {en} } @phdthesis{Frank2015, author = {Frank, Benjamin}, title = {Untersuchungen zur Autophagieinduktion in Leishmania major-infizierten Knochenmarksmakrophagen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137277}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Die von der WHO zu den 17 wichtigsten NTDs gez{\"a}hlte Leishmaniose wird durch intrazellul{\"a}re Parasiten der Gattung Leishmania hervorgerufen. Der Lebenszyklus der Parasiten besteht aus zwei Phasen. Die l{\"a}nglichen und beweglichen Promastigoten kennzeichnen die Phase in der Sandm{\"u}cke - der Vektor der Leishmaniose. Hingegen ist die Phase im S{\"a}ugerwirt durch runde unbewegliche Amastigoten charakterisiert. Aufgrund des Mangels an potenten antileishmanialen Therapien wurde in der vorliegenden Arbeit die Interaktion zwischen L. m. Parasiten und der Hauptwirtszelle, der Makrophage, v. a. in Hinblick auf autophage Prozesse in den infizierten Makrophagen n{\"a}her untersucht, um demgem{\"a}ß neue Erkenntnisse zu gewinnen, welche bei der Herstellung zuk{\"u}nftiger anti-leishmanialer Medikamente helfen k{\"o}nnten. Bei der Autophagie handelt es sich um einen katabolen Prozess, wodurch Zellen bei Nahrungsmangel oder zellul{\"a}rem Stress ihre Hom{\"o}ostase erhalten k{\"o}nnen. Durch diesen Prozess k{\"o}nnen {\"u}berfl{\"u}ssige oder besch{\"a}digte Organellen recycelt werden, um die Funktionen der Zelle aufrechtzuerhalten. Daneben {\"u}bernimmt Autophagie auch eine essenzielle Rolle bei der Abwehr von ins Zytosol eindringenden Pathogenen. Mittels des neu etablierten totalen Autophagiescore konnte festgestellt werden, dass Autophagie in L. m.-infizierten BMDM induziert wird. Die intrazellul{\"a}ren Amastigoten werden durch Autophagie in den BMDM verdaut. Die erh{\"o}hte autophage Aktivit{\"a}t konnte zudem durch Western-Blot-Analysen der autophagierelevanten Proteine ATG5, LC3B und UB best{\"a}tigt werden. Die molekulargenetischen Untersuchungen von L. m.-infizier-ten BMDM mithilfe von Affymetrix Microarrays f{\"u}hrten zu einem Netzwerk aus autophagierelevanten und infektionsspezifischen Genen, welches als LISA bezeichnet worden ist. Hier hat sich ebenfalls eine starke Verkn{\"u}pfung von autophagierelevanten Genen und den Genen der Glykolyse, einem zweiten katabolen Prozess, gezeigt. Zudem konnten zwei weitere autophagierelevante und infektionsspezifische Gene außerhalb von LISA identifiziert werden, n{\"a}mlich Bnip3 und Ctse, welche im Anschluss genauer untersucht worden sind. Bei beiden Genen konnte auf Proteinebene gezeigt werden, dass sie in L. m.-infizierten BMDM signifikant erh{\"o}ht sind. Durch siRNA-Analysen konnte {\"u}berdies beobachtet werden, dass beide f{\"u}r die erfolgreiche Elimination der Amastigoten essenziell sind. Somit konnte mit den Proteinen BNIP3 und CTSE zwei potenzielle neue Ansatzpunkte f{\"u}r m{\"o}gliche zuk{\"u}nftige antileishmaniale Therapien gefunden werden. Auch die in LISA enthaltenen Gene stellen prinzipiell vielversprechende Ziele f{\"u}r k{\"u}nftige Medikamente gegen Leishmaniose dar. Durch all diese Untersuchungen kommt man dem Ziel einer neuen, gezielten und nebenwirkungs{\"a}rmeren Behandlung der Leishmaniose einen Schritt n{\"a}her.}, subject = {Autophagie}, language = {de} } @article{BeissSpiegelBoesetal.2015, author = {Beiss, Veronique and Spiegel, Holger and Boes, Alexander and Scheuermayer, Matthias and Reimann, Andreas and Schillberg, Stefan and Fischer, Rainer}, title = {Plant expression and characterization of the transmission-blocking vaccine candidate PfGAP50}, series = {BMC Biotechnology}, volume = {15}, journal = {BMC Biotechnology}, number = {108}, doi = {10.1186/s12896-015-0225-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137327}, year = {2015}, abstract = {Background: Despite the limited success after decades of intensive research and development efforts, vaccination still represents the most promising strategy to significantly reduce the disease burden in malaria endemic regions. Besides the ultimate goal of inducing sterile protection in vaccinated individuals, the prevention of transmission by so-called transmission blocking vaccines (TBVs) is being regarded as an important feature of an efficient malaria eradication strategy. Recently, Plasmodium falciparum GAP50 (PfGAP50), a 44.6 kDa transmembrane protein that forms an essential part of the invasion machinery (glideosome) multi-protein complex, has been proposed as novel potential transmission-blocking candidate. Plant-based expression systems combine the advantages of eukaryotic expression with a up-scaling potential and a good product safety profile suitable for vaccine production. In this study we investigated the feasibility to use the transient plant expression to produce PfGAP50 suitable for the induction of parasite specific inhibitory antibodies. Results: We performed the transient expression of recombinant PfGAP50 in Nicotiana benthamiana leaves using endoplasmatic reticulum (ER) and plastid targeting. After IMAC-purification the protein yield and integrity was investigated by SDS-PAGE and Western Blot. Rabbit immune IgG derived by the immunization with the plastidtargeted variant of PfGAP50 was analyzed by immune fluorescence assay (IFA) and zygote inhibition assay (ZIA). PfGAP50 could be produced in both subcellular compartments at different yields IMAC (Immobilized Metal Affinity Chromatography) purification from extract yielded up to 4.1 mu g/g recombinant protein per fresh leaf material for ER-retarded and 16.2 mu g/g recombinant protein per fresh leave material for plasmid targeted PfGAP50, respectively. IgG from rabbit sera generated by immunization with the recombinant protein specifically recognized different parasite stages in immunofluorescence assay. Furthermore up to 55 \% inhibition in an in vitro zygote inhibition assay could be achieved using PfGAP50-specific rabbit immune IgG. Conclusions: The results of this study demonstrate that the plant-produced PfGAP50 is functional regarding the presentation of inhibitory epitopes and could be considered as component of a transmission-blocking malaria vaccine formulation.}, language = {en} } @article{OkoroBarquistConnoretal.2015, author = {Okoro, Chinyere K. and Barquist, Lars and Connor, Thomas R. and Harris, Simon R. and Clare, Simon and Stevens, Mark P. and Arends, Mark J. and Hale, Christine and Kane, Leanne and Pickard, Derek J. and Hill, Jennifer and Harcourt, Katherine and Parkhill, Julian and Dougan, Gordon and Kingsley, Robert A.}, title = {Signatures of adaptation in human invasive Salmonella Typhimurium ST313 populations from sub-Saharan Africa}, series = {PLoS Neglected Tropical Diseases}, volume = {9}, journal = {PLoS Neglected Tropical Diseases}, number = {3}, doi = {10.1371/journal.pntd.0003611}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143779}, pages = {e0003611}, year = {2015}, abstract = {Two lineages of Salmonella enterica serovar Typhimurium (S. Typhimurium) of multi-locus sequence type ST313 have been linked with the emergence of invasive Salmonella disease across sub-Saharan Africa. The expansion of these lineages has a temporal association with the HIV pandemic and antibiotic usage. We analysed the whole genome sequence of 129 ST313 isolates representative of the two lineages and found evidence of lineage-specific genome degradation, with some similarities to that observed in S. Typhi. Individual ST313 S. Typhimurium isolates exhibit a distinct metabolic signature and modified enteropathogenesis in both a murine and cattle model of colitis, compared to S. Typhimurium outside of the ST313 lineages. These data define phenotypes that distinguish ST313 isolates from other S. Typhimurium and may represent adaptation to a distinct pathogenesis and lifestyle linked to an-immuno-compromised human population.}, language = {en} }