Project description:Cervimycins A‒D are natural products of Streptomyces tendae HKI 0179 with promising activity against multidrug resistant staphylococci and vancomycin resistant enterococci. To initiate mode of action studies, we selected cervimycin C and D resistant (CmR) Staphylococcus aureus strains. Genome sequencing of CmR mutants revealed amino acid exchanges in the essential histidine kinase WalK, the Clp protease proteolytic subunit ClpP or the Clp ATPase ClpC, and the heat shock protein DnaK. Proteomic analysis revealed massive alterations in CmR-02 (amino acid exchanges: ClpP-I29F, DnaK-A112P, WalK-A243V) compared to the parent strain S. aureus SG511 Berlin, with major modifications in the heat shock regulon, the metal ion homeostasis and the carbohydrate metabolism. These effects were alleviated in the antibiotic susceptible suppressor mutant 02REV (amino acid exchanges: ClpP-I29F/M31I, WalK-A243V/S191L).
Project description:Squalene makes up 12 % of human skin surface lipids, however little is known about its affects on the host skin microbiome. Here we tested the effect of squalene on genetic regulation of staphylococci, showing that it profoundly affects expression virulence or colonisation determinants, and of iron uptake systems.
