METABOLIC DEVELOPMENT AND SECONDARY BIOSYNTHESIS IN PENICILLIUM URTICAE

Abstract

In cultures of Penicillium urticae Bainier, two successive physiological phases are distinguished. In the first, or trophophase, mycelial N, P, RNA, and —SH and the utilization of acetate for synthesis reach maximum values while glucose oxidation, mainly by the hexose monophosphate pathway, is most rapid. In the second, or idiophase, assimilation of N and P is reduced, RNA and —SH levels are lower, glucose is oxidized more slowly and mainly by glycolysis, fatty acids or mannitol accumulate, and special phenolic metabolites derived from 6-methyl-salicylic acid appear. The phase transition occurs sharply, with a minimum of respiratory activity and of acetate utilization; thereafter the pattern of secondary metabolism is established in a stepwise manner. The observations are interpreted in terms of sequential enzyme induction initiated by metabolic dislocation, and the generalized applications of such an hypothesis are considered.