Physiology of sporeforming bacteria associated with insects, m. Radiorespirometry of pyruvate, acetate, succinate, and glutamate oxidation

Abstract

Oxidation of pyruvate, acetate, succinate, and glutamate was compared in Bacillus thuringiensis, B. alvei, B. lentimorbus, and B. popilliae. Cells of B. thuringiensis and B. alvei in transition from vegetative growth to sporulation oxidized these substrates by tricarboxylic acid (TCA) cycle reactions. No TCA cycle activity was exhibited by B. lentimorbus and B. popilliae cells that do not sporulate. B. popilliae decarboxylated C-1 of pyruvate and glutamate; B. lentimorbus, C-1 of pyruvate only. B. thuringiensis and B. alvei oxidized pyruvate and acetate at a much higher rate in the absence of amino acids and related compounds than when these nutrients were exogenously supplied; in contrast, there was no appreciable increase in C-1 decarboxylation of pyruvate by B. lentimorbus and B. popilliae. No nutrient effect was observed on succinate and glutamate oxidation in any of these four organisms.