[Effect of cadmium on C-14-glucose uptake by Staphylococcus aureus]

The aim of the study was to evaluate an influence of Cd++ on 14C-glucose uptake by two strains of S. aureus resistant and sensitive to cadmium in 0.1 M phosphate buffer, pH 7.0. Uptake of this sugar in both strains is an active process in which energy comes from oxidation of endogenous substrates, what was shown in aerobic condition, anaerobic condition at temperatures of 37 degrees C and 4 degrees C, and with p-CMB and CCCP. In the resistant strains Cd++ at 10 microM concentration did not inhibit endogenous respiration, 14C-glucose uptake and its oxidation. This is due to presence of energy-dependent system of 2H+/Cd++ antiport coded by cadA genes located on penicillinase pII17810 plasmid, which eliminated Cd++ from bacterial cell. In the case of plasmid free variant deprived of this system, Cd++ is retained in cytoplasm and blocks endogenous respiration uptake, and oxidation of glucose.