title: Mode of action of the staphylococcin-like peptide Pep 5 and culture conditions effecting its activity.
abstract: Pep 5, a staphylococcin-like peptide produced by Staphylococcus epidermidis 5 was bactericidal for staphylococci and micrococci (Fig. 1). A stable L-phase variant of Staphylococcus aureus, but not of Streptococcus faecalis, was susceptible, too, indicating that the selectivity of Pep 5 is not due to the presence of a cell wall receptor. Addition of Pep 5 to cultures of the indicator strain caused immediate inhibition of DNA, RNA, protein, and polysaccharide synthesis (Fig. 5). The action of Pep 5 could be inhibited by increasing the cation content of the medium (e.g., to 100 mM Mg2+ or 600 mM K+) (Fig. 3), indicating a primary binding to anionic sites on the cell wall. Sublethally injured cells could be rescued by the addition of trypsin or 1 M KCl (Fig. 4).
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D001430:Bacteriocins / Q000494:pharmacology*; D003470:Culture Media; D004269:DNA, Bacterial / Q000096:biosynthesis; D006863:Hydrogen-Ion Concentration; D007740:L Forms / Q000187:drug effects; D008837:Micrococcus / Q000187:drug effects*; D009994:Osmolar Concentration; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D012329:RNA, Bacterial / Q000096:biosynthesis; D013210:Staphylococcus / Q000187:drug effects*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins; D003470:Culture Media; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D012329:RNA, Bacterial