title: Changes in the Cytoplasmic Composition of Amino Acids and Proteins Observed in Staphylococcus aureus during Growth under Variable Growth Conditions Representative of the Human Wound Site.
abstract: Staphylococcus aureus is an opportunistic pathogen responsible for a high proportion of nosocomial infections. This study was conducted to assess the bacterial responses in the cytoplasmic composition of amino acids and ribosomal proteins under various environmental conditions designed to mimic those on the human skin or within a wound site: pH6-8, temperature 35-37°C, and additional 0-5% NaCl. It was found that each set of environmental conditions elicited substantial adjustments in cytoplasmic levels of glutamic acid, aspartic acid, proline, alanine and glycine (P< 0.05). These alterations generated characteristic amino acid profiles assessed by principle component analysis (PCA). Substantial alterations in cytoplasmic amino acid and protein composition occurred during growth under conditions of higher salinity stress implemented via additional levels of NaCl in the growth medium. The cells responded to additional NaCl at pH 6 by reducing levels of ribosomal proteins, whereas at pH 8 there was an upregulation of ribosomal proteins compared with the reference control. The levels of two ribosomal proteins, L32 and S19, remained constant across all experimental conditions. The data supported the hypothesis that the bacterium was continually responding to the dynamic environment by modifying the proteome and optimising metabolic homeostasis.
authors.affiliation: Metabolic Research Group, Faculty of Science and Information Technology, School of Environmental and Life Sciences, Department of Biology, University Drive, Callaghan, 2308, NSW, Australia.|Department of Biology, College of Science, University of Ha'il, P.O. 2440, Hail, Saudi Arabia.
authors.forename: Mousa M
authors.initials: MM
authors.lastname: Alreshidi
authors.affiliation: Metabolic Research Group, Faculty of Science and Information Technology, School of Environmental and Life Sciences, Department of Biology, University Drive, Callaghan, 2308, NSW, Australia.
authors.forename: R Hugh
authors.initials: RH
authors.lastname: Dunstan
authors.affiliation: Department of Chemistry and Molecular Biology, Gothenburg University, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Gottfries
authors.affiliation: Metabolic Research Group, Faculty of Science and Information Technology, School of Environmental and Life Sciences, Department of Biology, University Drive, Callaghan, 2308, NSW, Australia.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Macdonald
authors.affiliation: Metabolic Research Group, Faculty of Science and Information Technology, School of Environmental and Life Sciences, Department of Biology, University Drive, Callaghan, 2308, NSW, Australia.
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Crompton
authors.affiliation: Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.
authors.forename: Ching-Seng
authors.initials: CS
authors.lastname: Ang
authors.affiliation: Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Williamson
authors.affiliation: Metabolic Research Group, Faculty of Science and Information Technology, School of Environmental and Life Sciences, Department of Biology, University Drive, Callaghan, 2308, NSW, Australia.
authors.forename: Tim K
authors.initials: TK
authors.lastname: Roberts
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D025341:Principal Component Analysis; D012015:Reference Standards; D012269:Ribosomal Proteins / Q000378:metabolism; D013211:Staphylococcus aureus / Q000254:growth & development* / Q000378:metabolism*; D014947:Wounds and Injuries / Q000382:microbiology* / Q000473:pathology
chemical_list: D000596:Amino Acids; D012269:Ribosomal Proteins