The effect of Antipiriculin-A and Phenyl mercuric acetate on the nitrogen metabolism of Piricularia oryzae

Abstract

This paper describes the nitrogen metabolism of P. oryzae and its inhibition by Antimycin-A (AP), Blastmycin (BM), and Phenyl mercuric acetate (PMA). According to the rate of growth of P. oryzae, the various nitrogen sources tested were divided into three groups. The most suitable group for fungal growth contains, for instance, glutamic acid, aspartic acid, serine, leucine, NH₄Cl and so on. The amino acids belonging to the most suitable group were oxidized by P. oryzae in a short period of incubation, and the most of these oxidation was completely inhibited by AP, BM, and PMA.
Two types of transamination were found in P. oryzae. One of these reaction was that of between α-ketoglutaric acid and alanine, and another was between α-ketoglutaric acid and aspartic acid. In the case of cell level, the former reaction was completely inhibited by AP, BM, and PMA at 18 hours after incubation, while the latter was moderately inhibited even by PMA. Using the extracted enzyme solution, however, no inhibitory effects of both AP and BM on these two reactions were confirmed, although a strong inhibition was detected by PMA.