Glutamine metabolism in nitrogen-starved conidia of Neurospora crassa.

During nitrogen deprivation, de novo synthesis of glutamine synthetase was induced in non-growing conidia of Neurospora crassa. When ammonia or glutamine was added to conidia which had been deprived of nitrogen, glutamine and arginine accumulated at a higher rate than in condia not deprived of nitrogen. The degradation of exogenous glutamine to glutamate is apparently a necessary step in the accumulation of glutamine and arginine within the conidia. In non-growing conidia, a cycle probably operates in which glutamine is degraded and resynthesized. The advantages of such a cycle would be that the carbon and nitrogen could be used to synthesize amino acids in general, as well as for the synthesis and accumulation of arginine and/or glutamine in particular.