Ricerche sul meccanismo di azione della cocliobolina B: effetti sul metabolismo ossidativo diMicrococcus pyogenesvar.aureus

Abstract

Abstract STUDIES ON MECHANISM OF COCHLIOBOLIN ACTIVITY. B: EFFECTS ON OXIDATIVE METABOLISM OF MICROCOCCUS PYOGENES VAR. AUREUS. — Endogenous respiration of washed 24-hours old cells of Micrococcus pyogenes var. aureus was markedly decreased by cochliobolin, which also completely prevented pyruvate, succinate, fumarate and malate oxidation. The toxin inhibited also lactate and α-ketoglutarate utilization by Micrococcus cells, while aerobic respiration of glucose was only slightly reduced, and anaerobic breakdown increased. These phenomena were irreversible, and depended upon the pH of media and the lenght of incubation periods. In contrast, respiratory activities of cell-free homogenates and acetone powders of Micrococcus were refractory to the toxin, and the oxidation of Krebs cycle intermediates was not affected. These phenomena suggest that, although cochliobolin prevens the respiratory metabolism of Micrococcus cells, the initial locus of interference probably is not one of the common respiratory enzim...