Project description:Bacteria actively secrete extracellular vesicles (EVs), spherical nano-sized proteolipids into the extracellular milieu. Bacterial EVs have gained wide interests as non-living complex vaccines or delivery vehicles. However, no studies have used bacterial EVs in treating cancer so far. Our results showed remarkable capability of EVs derived from Staphylococcus aureus RN4220 wild-type to effectively induce long-term anti-tumor immune responses that can fully eradicate established tumors without notable adverse effects. This anti-tumor effect was IFN-γ-dependent, and we present a comprehensive proteome of S. aureus RN4220 wild-type EVs to investigate which vesicular components induce the anti-tumor effects.
Project description:Staphylococcus aureus is a gram-positive cocci and an important human commensal bacteria and pathogen. S. aureus infections are increasingly difficult to treat because of the emergence of highly resistant MRSA (Methicillin-resistant S. aureus) strains. Here we present a method to study differential gene expression in S. aureus using high-throughput RNA-sequencing (RNA-seq). We use RNA-seq to examine the differential gene expression in S. aureus RN4220 cells containing an exogenously expressed transcription factor and between two S. aureus strains (RN4220 and NCTC8325-4). The information provided by RNA-seq was a significant advance over previously described microarray based techniques. We investigated the sequence and gene expression differences between RN4220 and NCTC8325-4 and used the RNA-seq data to identify S. aureus promoters suitable for in vitro analysis. We used RNA-seq to describe, on a genome wide scale, genes positively and negatively regulated by a phage encoded transcription factor, gp67. RNA-seq offers the ability to study differential gene expression with single-nucleotide resolution, and is a considerable improvement over the predominant genome-wide transcriptome technologies used in S. aureus. RNA-seq analysis of Staphylococcus aureus RN4220 (electrocompetent strain) carrying either empty pRMC2 (inducible expression vector) or pRMC2 carrying the ORF67 gene (encodes gp67). Both strains were grown to OD 0.2 and transgene expression was induced with 100ng/ml anhydrotetracycline. As a control, Staphylococcus aureus strain NCTC8325-4 (non-electrocompetent strain) was grown under identical conditions except without the addition of anhydrotetracycline.
Project description:Staphylococcus aureus is a gram-positive cocci and an important human commensal bacteria and pathogen. S. aureus infections are increasingly difficult to treat because of the emergence of highly resistant MRSA (Methicillin-resistant S. aureus) strains. Here we present a method to study differential gene expression in S. aureus using high-throughput RNA-sequencing (RNA-seq). We use RNA-seq to examine the differential gene expression in S. aureus RN4220 cells containing an exogenously expressed transcription factor and between two S. aureus strains (RN4220 and NCTC8325-4). The information provided by RNA-seq was a significant advance over previously described microarray based techniques. We investigated the sequence and gene expression differences between RN4220 and NCTC8325-4 and used the RNA-seq data to identify S. aureus promoters suitable for in vitro analysis. We used RNA-seq to describe, on a genome wide scale, genes positively and negatively regulated by a phage encoded transcription factor, gp67. RNA-seq offers the ability to study differential gene expression with single-nucleotide resolution, and is a considerable improvement over the predominant genome-wide transcriptome technologies used in S. aureus.
Project description:To determine if significant genomic changes are associated with the development of vancomycin intermediate Staphylococcus aureus, genomic DNA microarrays were performed to compare the initial vancomycin susceptible Staphylococcus aureus (VSSA) and a related vancomycin intermediate Staphylococcus aureus (VISA) isolate from five unique patients (five isolate pairs). Keywords: comparative genomic hybridization
Project description:The purpose of this study was to compare the global, growth phase-dependent transcriptional profiles of two isolates of Staphylococcus aureus. One isolate is a prototypic laboratory strain named RN6390, and has been used frequently as a model organism for study of staphylococcal physiology and virulence. However, recent studies indicate that RN6390 is not, in general, genotypically or phenotypically representative of clinical isolates of Staphyloccos aureus. Therefore, there is no current comprehensive picture of gene expression patterns in a virulent, clinical isolate of Staphyloccous aureus. For these reasons, we compare the transcriptional profile of RN6390 to that of a virulent clinical isolate, UAMS-1. Also included in this study is profiling of two UAMS-1 regulatory mutants, UAMS-155, and UAMS-929. These strains possess mutations in the accessory gene regulator (agr) and staphylococcal accessory regulator (sarA) genes, respectively. These two genes are well described global regulatory molecules that are reported to play important roles in controlling virulence factor production and biofilm formation in Staphylococcus aureus. However, most study of these two molecules has been limited to laboratory strains such as RN6390. For these reasons, this study also includes transcriptional profiling of UAMS agr and sarA mutants. Keywords: Comparative, growth phase-dependent transcriptional profiling of bacterial strains and isogenic regulatory mutants