[Changes in the electron transport chain in Escherichia coli depending on the cultivation conditions and growth phase].

Changes in the electron transport chain of E. coli K-12 were studied as a function of the growth phase and the nature of a terminal electron acceptor in the growth medium. The content of flavins in the preparations of bacterial membranes hardly changed in all cases. The highest concentration of quinones was observed in the bacterial membranes at the stationary growth phase under anaerobic conditions of growth in the presence of nitrate. These membranes contained also the greatest amount of cytochrome beta1. The concentration of cytochrome alpha2 in all the membranes was low and varied among different preparations. All the membranes contained a CO-binding pigment whose content was maximal in the membranes of "nitrate" cells. The membranes of cells grown under aerobic conditions oxidized malate, apart from NADH and lactate, whereas the membranes of cells cultivated under anaerobic conditions in the presence of nitrate oxidized formiate. In most cases, the oxidase activity of the membranes of cells collected at the stationary growth phase was higher cf. the exponential phase.