Project description:Microarray expression profiling of S. aureus lavaged from murine lungs after residence times between 30 minutes and 6 hours compared to post-exponential phase or early log phase growth in Luria-Betani broth.
Project description:More than 200 direct CodY target genes in Staphylococcus aureus were identified by genome-wide analysis of in vitro DNA binding. This analysis, which was confirmed for some genes by DNase I footprinting assays, revealed that CodY is a direct regulator of numerous transcription units associated with amino acid biosynthesis, transport of macromolecules and virulence. The virulence genes regulated by CodY fell into three groups. One group was dependent on the Agr system for its expression; these genes were indirectly regulated by CodY through its repression of the agr locus. A second group was regulated directly by CodY. The third group, which includes genes for alpha-toxin and capsule synthesis, was regulated by CodY in two ways, i.e., by direct repression and by repression of the agr locus. Since S. aureus CodY was activated in vitro by the branched chain amino acids and GTP, CodY appears to link changes in intracellular metabolite pools with the induction of numerous adaptive responses, including virulence. Affymetrix GeneChips were used to compare the transcript titers of S. aureus strains UAMS-1 (wild type) and corresponding agr- (strain CM18), codY- (strain MS1), and agr- codY- (strain CM19) isogenic mutant strains during exponential and stationary phase growth. At least two biological replicates were assessed for each strain and each growth phase.
Project description:Microarray expression profiling of S. aureus lavaged from murine lungs after residence times between 30 minutes and 6 hours compared to post-exponential phase or early log phase growth in Luria-Betani broth. 21 samples analyzed, all replicates are biological replicates (independent biological experiments): 8 replicates of the overnight culture used for intranasal inoculation, 4 each from lavage at 0.5 hours and 2.0 hours, 3 from lavage after 6 hours and 2 from growth in fresh LB for 30 minutes.
Project description:MepR is a substrate-responsive repressor of mepR and mepA, which encode itself and a MATE family multidrug efflux pump. Microarray analyses of Staphylococcus aureus SH1000 and its mepR-disrupted derivative revealed changes in expression of many genes in addition to mepR and mepA, notably several involved in virulence Keywords: Staphylococcus aureus, MATE efflux pump, MepR Staphylococcus aureus strains SH1000 wildtype and mepR were grown in duplicate to exponential and post-exponential phase (corresponding to an A550 nm of 0/4 and 2.0 respectively). RNA was harvested, converted to cDNA, labelled with Biotin and used to probe custom-designed Affymetrix antisense S.aureus GeneChips. Eight samples in total were prepared and analyzed.
Project description:Staphylococcus aureus is an important human pathogen that causes life-threatening infections, and is resistant to the majority of our antibiotic arsenal. This resistance is complicated by the observation that most antibacterial agents target actively growing cells, thus, proving ineffective against slow growing populations, such as cells within a biofilm or in stationary phase. Recently, our group generated updated genome annotation files for S. aureus that not only include protein-coding genes but also regulatory and small RNAs. As such, these annotation files were used to perform a transcriptomic analysis in order to understand the metabolic and physiological changes that occur during transition from active growth to stationary phase; with a focus on sRNAs. We observed â¼24% of protein-coding and 34% of sRNA genes displaying changes in expression by â¥3-fold. Collectively, this study adds to our understanding of S. aureus adaptation to nutrient-limiting conditions, and sheds new light onto the contribution of sRNAs to this process. Bacterial cells were grown in TSB medium at 37°C with shaking for 3h (exponential growth phase) or 16h (stationary growth phase).
Project description:S. aureus has a propensity to cause endocarditis; diabetes mellitus is a frequent underlying comorbitity in patents with S. aureus endocarditis. S. aureus Affymetrix GeneChips were used to compare S. aureus expression properties in cardiac vegatations isolated from diabetic and nondiabetic rats. S. aureus Affymetrix GeneChips were also used to compare the S. aureus expression properties of cardiac vegatations (both diabetic and nondiabetic) in comparsions to planktonic cells. Few differences were observed between the expression properties of S. aureus harvested from diabetic vs. nondiabetic cardiac vegatations. Significant differences were observed between the expression properties of S. aureus harvested from cardiac vegetations in comparison to exponential and/or stationary phase planktonically grown cells.
Project description:S. aureus has the propensity to survive a range of NaCl challenge conditions We used commercially available Affymetrix S. aureus GeneChips (part number 900514) to compare the gene expression properties of wild type cells during growth at no or high (2M) NaCl. S. aureus strain USA300-lac cells were grown to late exponential phase growth in the absence or presence of 2M NaCl, total bacterial RNA was isolated and subjected to GeneChip hybridization and analysis. We sought to determine the regulatory effects of high NaCl.
Project description:S. aureus has a propensity to cause endocarditis; diabetes mellitus is a frequent underlying comorbitity in patents with S. aureus endocarditis. S. aureus Affymetrix GeneChips were used to compare S. aureus expression properties in cardiac vegatations isolated from diabetic and nondiabetic rats. S. aureus Affymetrix GeneChips were also used to compare the S. aureus expression properties of cardiac vegatations (both diabetic and nondiabetic) in comparsions to planktonic cells. Few differences were observed between the expression properties of S. aureus harvested from diabetic vs. nondiabetic cardiac vegatations. Significant differences were observed between the expression properties of S. aureus harvested from cardiac vegetations in comparison to exponential and/or stationary phase planktonically grown cells. S. aureus strain COL was used to establish cardiac vegetations in diabetic and nondiabetic rats or grown in laboratory medium to exponential or stationary phase, total bacterial RNA was isolated, labeled and applied to Affymetrix GeneChips. We sought to determine whether the transcriptional profiles of S. aureus differed in diabetic vs. nondiabetic rats and whether vegetations differed from that of planktonic S. aureus.
Project description:Genes that showed altered expression in Stk1 and Stp1 deficient Staphylococcus aureus Newman were identified. strain comparison, global regulation