EFFECTS OF STARVATION ON THE METABOLISM OF CHLORELLA

Abstract

Chlorella has been widely used in studies on photosynthesis with but little attention to possible variations in its metabolic activities. The metabolism of other microorganisms has proved to be quite variable and dependent upon previous history as well as upon prevailing environmental conditions. It has been common practice, for instance, to study resting cells as opposed to actively proliferating cells. Resting cells have been variously obtained by removal of the nitrogen source from the nutrient medium, by washing the cells, or starving the cells of organic nutrients for a period of time. Assimilation of carbon may be much more efficient in resting cells than in growing cells (cf. 10) and for that reason the former have most frequently been used in studies on oxidative assimilation. In Chlorella oxidative assimilation has been studied in resting cell preparations obtained as a result of starvation, i.e., aerobic incubation in the dark in the absence of organic nutrients (6). As a background for the larger problem of assimilation in Chlorella it becomes important to investigate the changes that take place during starvation.