Torula utilis was grown in a chemostat, at several dilution rates, in media containing growth-limiting concentrations of glucose, xylose and ethanol; it was similarly grown in an NH4+-limited medium (carbon source, glucose). The ‘steady state’ rates of oxygen uptake of cultures, and QO2 values for washed suspensions of organisms separated from the cultures and incubated with each substrate, were determined at each dilution rate. Differences in oxidation rates indicated quantitative changes in the ‘constitutive’ enzyme content of organisms, which varied according to the growth rate and/or the nature of the growth-limiting substrate. The significance of these changes in terms of metabolic regulation and economy of enzyme synthesis is discussed.
HerbertD.1958; Some principles of continuous culture. Recent Progress in Microbiology, VII Int. Congr. Microbiol381
HerbertD.1961; The chemical composition of micro-organisms as a function of their environment. Microbial Reaction to Environment. Symp. Soc. gen. Microbiol. 11:391
SykesJ., TempestD. W.1965; The effect of magnesium and of carbon limitation on the macromolecular organisation and metabolic activity of Pseudomonas sp., strain c-1b. Biochim. biophys. Acta 103:93
TempestD. W., HunterJ. R.1965; Influence of temperature on the macromolecular composition of c (glycerol)-limited and Mg2+-limited Aerobacter aerogenes, growing in a chemostat. J. gen. Microbiol. 41: in the Press