Membrane Lipid Changes During Formation of a Functional Electron Transport System in Staphylococcus aureus

Abstract

Addition of oxygen to a culture of anaerobically growing Staphylococcus aureus results in the formation of a membrane-bound, functional electron transport system. With the shift to aerobic growth, there is at least a 15-fold increase in cytochrome a and at least a 55-fold increase in cytochrome oxidase o . At the completion of the shift to aerobic growth, the cytochrome levels equal those found in bacteria grown with aeration throughout the entire growth cycle. Cytochromes b 1 and o are formed first. Their synthesis slows when cytochrome a becomes detectable. Concentrations of cytochromes b 1 and sometimes cytochrome a increase late in the adaptive period. Concomitant with this is a decrease in the oxygen tension at which the rate of oxygen utilization becomes dependent on the oxygen concentration. During the shift to aerobic growth, the protoheme content increases ninefold, and all the protoheme can be accounted for in enzymatically reducible cytochrome b 1 and cytochrome oxidase o . Protoheme, but not a functional cytochrome system, is synthesized by anaerobically growing S. aureus . Heme a appears only after a period of aerobic growth. During the shift to aerobic growth, there is a 1.6-fold increase in the vitamin K 2 content, with an alteration in the ratios of the 35 and 45 carbon side chain isoprenologues. A twofold increase in phosphatidyl glycerol and a 1.6-fold increase in cardiolipin occur with the shift to aerobic growth. Lysyl-phosphtidyl glycerol remains essentially constant in this period. Concentrations of mono- and diglucosyl diglycerides increase coordinately 1.3-fold during the shift to aerobic growth at a 2.5 to 1 m ratio.