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A study of the nitrate and nitrite discharge from the mutant cells of Neurospora crassa lacking nitrate and nitrite reductase activities

Research paper by S. Yu. Filippovich, G. P. Bachurina, M. S. Kritsky

Indexed on: 01 May '07Published on: 01 May '07Published in: Applied Biochemistry and Microbiology



Abstract

The Neurospora crassa mutants nit-2 (lacking both nitrite and nitrate reductases) and nit-6 (lacking nitrite reductase) grown in the medium with ammonium chloride as a sole source of nitrogen discharged nitrate and nitrite ions into culture medium. For nit-2, the content of nitrate exceeded that of nitrite in both the homogenate of fungal cells and growth medium; moreover, this difference was more pronounced in the culture medium. Unlike nit-2, the content of nitrite in the cultivation medium of the nit-6 mutant irradiated with visible light for 30 min during the lag phase of carotenogenesis photoinduction displayed a trend of increase as compared with the dark control. Further (to 240 min) irradiation of cells, i.e., irradiation during biosynthesis of carotenoid pigments, leveled this difference.