NADPH-dependent glutamate dehydrogenase activity inGibberella zeae

Utilization of Nitrogen Sources by Gibberella zeae

“…In fungi such as Neurospora crassa Shear and Dodge, Aspergillus nidulans (Eidam) Wint., and Saccharomyces cerevisiae Hansen where the genetics and physiology of nitrogen metabolism have been extensively studied, complex genetic and regulatory mechanisms are known (cf. Enzymes studied include: NADPH-glutamate dehydrogenase (Kinzel and Leslie, 1985), acid phosphatase (Yoshida and Tamiya, 1971;Sano and Ui, 1981) and nitrate reductase (Ottow and von Klopotek, 1969;Chebotarev and Zemlyanukhin, 1973). Relatively little attention has been paid to the nitrogen metabolic machinery in the Fusaria (cf.…”

A Nitrate Non-utilizing Mutant of Gibberella Zeae

“…zeae 1285 sources, and utilizable organic nitrogen sources are reduced to a handful of amino acids and closely related compounds. N ADPH-dependent glutamate dehydrogenase activity levels are comparable in the mutant and the wild-type when the cells are grown in a medium containing glutamine or monosodium glutamate as a sole nitrogen source (Kinzel & Leslie, 1985). The effective metabolism of glutamate to glutamine and of glutamine to glutamate suggests that functional glutamine synthetase and glutamate synthase systems are both present in the mutant strain.…”

“…This mutation was formerly designated gdh because it was believed to result in a defect in glutamate dehydrogenase (Leslie & Kinzel, 1983); this preliminary diagnosis was later found to be incorrect (Kinzel & Leslie, 1985), and the mutation has thus been renamed nnu (nitrate nonutilizing). I have identified compounds which can be used by the nnu mutant as sole source of nitrogen and as sole source of both carbon and nitrogen, measured growth rates on complex media, and documented unusual synergistic growth responses.…”

“…Some strains of this fungus are used commercially to make the fungal sex pheromone zearalenone (Keith, 1972;Wolf & Mirocha, 1973), which is subsequently processed to zearanol, an anabolic agent for ruminants (Hidy et al, 1977). Some preliminary studies of the enzymology of nitrogen catabolism in this organism have been conducted (Leslie & Kinzel, 1983;Kinzel & Leslie, 1985).…”

“…The activities in the fusaria of some of the enzymes related to nitrogen metabolism have been briefly examined. Enzymes studied include : NADPH-dependent glutamate dehydrogenase (Kinzel & Leslie, 1985), acid phosphatase (Yoshida & Tamiya, 1971;Sano & Ui, 1981) and nitrate reductase (Ottow & von Klopotek, 1969;Chebotarev & Zemlyanukhin, 1973).…”