Effects of growth phase and oxygen supply on the cytochrome composition and morphology of Arthrobacter crystallopoietes

Cytochrome d concentration in Arthrobacter crystallopoietes can be induced or inhibited by varying the oxygen content of the cultivation medium. Its synthesis is stimulated at a low oxygen concentration, as is usually present in the stationary growth phase, where spheres exclusively occur. The rod-sphere transition is dependent not only on the oxygen supply but also on other factors influencing the growth rate, such as nutrients and temperature. At a high growth rate, rods are formed, and at a low growth rate, spheres are formed. Under oxygencontrolled conditions, spheres can be induced both in the presence or absence of cytochrome d.