Project description:Accurate annotation of regulatory RNAs is a complex task but nevertheless essential as sRNA molecular and functional studies ensue from it. Several formerly considered small RNAs (sRNA) are now known to be parts of UTR transcripts. In light of experimental data, we review hundreds of Staphylococcus aureus putative regulatory RNAs. We pinpoint those that are likely acting in trans and are not expressed from the opposite strand of a coding gene. We conclude that HG003, a NCTC8325 derivative strain, has about 50 bona fide sRNAs, indicating that these RNAs are less numerous than commonly stated.
Project description:In this study we compare logrithmically grown Staphylococcus aureus SAUSA300 wildtype to a transposon mutant that is disrupted in bshC, the third step in bacillithiol biosynthesis using RNASeq to identify novel pathways where bacillithiol may be involved.
Project description:Purpose: The goal of this study was to identify Staphylococcus aureus genes which are important during establishment of metastatic infections in bloodstream infections. Methods: Pooled mariner transposon mutant libraries were generated as previously described (PMID: 27185949). The libraries were sequenced on the Illumina HiSeq 2500 platform with the transposon-specific oligonucleotide primer Himar1-Seq. Illumina adapter sequences were removed via cutadapt version 1.2.1. The reads were filtered for size (>16 bp) and to contain the signature transposon inverted repeat. Reads were mapped to the Staphylococcus aureus 6850 genome (RefSeq accession NC_022222.1) by Bowtie2 v2.1.0. Identification of depleted and enriched mutants was performed via DESeq2 version 1.6.2. Results: S. aureus genes were identified which were upregulated or downregulated upon iduced expression of the LysR-type transcriptional regulator RSAU_000852 in Staphylococcus aureus 6850. Conclusions: Our study identifies a gene for a LysR-type transcription regulator, which is involved in metabolic adaptation of the pathogen during colonization of secondary infection sites in a bloodstream infection model.
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of ϕNM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process. Following strains were grown in TSA broth: Staphylococcus aureus USA300 (reference) Staphylococcus aureus USA300 with deletion of ϕSa2usa (Query) Staphylococcus aureus USA300 with deletion of ϕSa3usa (Query) Staphylococcus aureus USA300 Prophage-free mutant (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa2mw (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa3usa (Query) strain: Staphylococcus aureus USA300 Prophage-free mutant lysogenized with both ϕSa2mw and ϕSa3usa (Query) RNA samples were harvested at early log, midlog and stationary phase.Samples were hybridized on aminosilane coated slides with 70-mer oligos.
Project description:Staphylococcus aureus is one of the most important pathogens in humans and animals, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. Rhein, a natural plant product, has potential antimicrobial activity against Staphylococcus aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with rhein. Results provided insight into mechanisms involved in rhein - Staphylococcus aureus interactions. Keywords: rhein response
Project description:Investigation of mRNA expression level changes in a Staphylococcus aureus Mu50 delta-SAV1322 mutant, compared to the wild-type strain. A comparison of the wild-type and the mutant transcription profiles