Project description:S. aureus response to exogenous fatty acid (oleic acid) Gene expression profiles were generated by microarray analysis of S. aureus cells grown in media without or with oleic aicd Comparison of expression profiles after growth of S. aureus in exogenous fatty acid S. aureus was grown in media with and without oleic acid to an OD600nm of 0.5, and RNA was extracted to look at the gobal gene expression.
Project description:S. aureus response to exogenous fatty acid (oleic acid) Gene expression profiles were generated by microarray analysis of S. aureus cells grown in media without or with oleic aicd
Project description:Genome-wide transcriptional profiling studies of the growth of bacteria with antimicrobial agents often reveals aspects of the drug-specific protective bacterial response. Fusidic acid is a steroid antimicrobial that inhibits protein synthesis by interfering with the release of elongation factor G (EF-G) after it has functioned in the translocation step. Two hundred and seventy two genes were both up- and down-regulated in a fusidic acid-susceptible strain of Staphylococcus aureus following challenge with 2 mg/L-1 fusidic acid for 15 min. Many genes altered by fusidic acid challenge are associated with protein synthesis such as fusA, which encodes EF-G which was up-regulated following exposure to the drug. The Staphylococcus microarray meta-database which curates and compares S. aureus transcriptome data revealed that the fusidic acid stimulon has the greatest overlap with the S. aureus cold shock- and stringent-responses. Six out of 9 autolysin genes making up the two component YycFG regulon (ssaA1-ssaA4, isaA and sceD) were also upregulated by fusidic acid; as were a carboxylesterase (est) and two putative Emr-Qac-like multidrug efflux pumps (emr-qac1 and emr-qac2). Genes down-regulated by fusidic acid induction encode a putative secreted acid phosphatase (sapS) and a number of protease genes (yjbG1, yjbG2, htrA1 and htrA2). Transcriptional analysis in conjunction with mutant fusidic acid susceptibility experiments revealed that th45 e virulence gene regulatory agr operon, a YycFG controlled peptidoglycan hydrolase gene isaA and the proteases htrA1 and htrA2 are required for the expression of wild-type levels of fusidic acid susceptibility.
Project description:Lignin is an aromatic plant cell wall polymer that facilitates water transport through the vasculature of plants. Although lignin’s ability to reduce bacterial growth been previously reported, it’s hydrophobicity complicates the ability to examine its biological effects on living cells in aqueous growth media. We recently described the ability to solvate lignin in Good’s buffers with neutral pH, a breakthrough that has allowed examination of lignin’s antimicrobial effects against the human pathogen Staphylococcus aureus. We previously showed that lignin damages the S. aureus cell membrane, causes increased cell clustering, and inhibits growth synergistically with tunicamycin, a teichoic acid synthesis inhibitor. In this current study, additional experiments were performed to better understand the physiological and transcriptomic responses of S. aureus to lignin. Intriguingly, lignin restored the susceptibility of genetically resistant S. aureus isolates to β-lactam antibiotics, dysregulated intracellular pH, and impaired normal cell division. Additionally, RNAseq analysis of lignin-treated cultures revealed a number of gene expression changes related to cell envelope, cell wall physiology, fatty acid metabolism and stress resistance. Altogether, these results represent the first comprehensive analysis of lignin’s antibacterial activity against S. aureus that provide clarity in deciphering the mechanisms of lignin’s antibacterial activity, while supporting the notion that lignin has potential to be repurposed for biomedical applications.
Project description:In the present study, we employed Affymetrix Staphylococcus aureus GeneChip arrays to investigate the dynamics of global gene expression profiles during the cellular response of Staphylococcus aureus to peracetic acid, which involved initial growth inhibition and subsequent partial recovery. Keywords: Time course
Project description:Staphylococcus aureus Newman and Staphylococcus epidermidis Tu3298, 20 minutes post challenge with sub-inhibitory concentration of sapienic acid vs equivalent concentration of ethanol. Challenge was added at mid logarithmic growth (OD600 0.5). Biological triplicates of samples were sequenced.
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 an important food poisoning bacterium. In food preservation, acidification is a well-known method. Permeant weak organic acids, like lactic and acetic acids, are known to be more effective against bacteria than inorganic strong acids (e.g., HCl). Growth experiments and metabolic and transcriptional analyses were used to determine the responses of a food pathogenic S. aureus strain exposed to lactic acid, acetic acid, and HCl at pH 4.5. Lactic and acetic acid stress induced a slower transcriptional response and large variations in growth patterns compared with the responses induced by HCl. In cultures acidified with lactic acid, the pH of the medium gradually increased to 7.5 during growth, while no such increase was observed for bacteria exposed to acetic acid or HCl. Staphylococcus aureus increased the pH in the medium mainly through accumulation of ammonium and the removal of acid groups, resulting in increased production of diacetyl (2,3-butanedione) and pyrazines. The results showed flexible and versatile responses of S. aureus to different types of acid stress. As measured by growth inhibition, permeant organic acid stress introduced severe stress compared with the stress caused by HCl. Cells exposed to lactic acid showed specific mechanisms of action in addition to sharing many of the mechanisms induced by HCl stress. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-87
Project description:Pseudomonas aeruginosa and Staphylococcus aureus are often co-isolated in persistent infections. The goal of this study was to determine how secreted products from S. aureus affect gene expression in surface-associated P. aerguinosa undergoing emergent motility. Therefore, media salts control or S. aureus supernatant was added to agar plates at 25% total volume. P. aeruginosa was inoculated on the agar and gene expression was measured from the leading edge after 17 h incubation using RNA-seq. P. aeruginosa moving on the agar containing S. aureus supernatant had an upregulation in genes involved in intermediate metabolite uptake and a downregulation in heme biosynthesis, response to heat, Type III Secretion System, and aerobic respiration pathways.