title: Selection of succinic dehydrogenase mutants of Neurospora crassa.
abstract: A method is described which permits the selection of mutants of Neurospora crassa that are deficient in succinic dehydrogenase activity. The method relies on the observation that succinic dehydrogenase-deficient strains fail to reduce the dye nitrotetrazolium blue when overlaid with the dye in the presence of succinate and phenazine methosulfate. Wild-type colonies reduced the dye and turned blue, whereas mutant colonies remained colorless. In this communication we present studies of a mutant, SDH-1, isolated by this method. The mutant had 18% of the succinic dehydrogenase activity of the parent strain used in the mutation experiments as determined from the ratio of Vmax activities obtained from Lineweaver-Burk plots. The SDH-1 mutant segregated in a Mendelian manner when back-crossed to its parent strain. Succinate oxidase activity in SDH-1 was low and was markedly inhibited by adenosine 5'-diphosphate. The succinate oxidase activity of the parent strain was high and was not affected by the presence of adenosine 5'-diphosphate.
mesh_terms: D009154:Mutation; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D010084:Oxidation-Reduction; D013385:Succinate Dehydrogenase / Q000235:genetics*; D013386:Succinates / Q000378:metabolism
chemical_list: D013386:Succinates; D009580:Nitroblue Tetrazolium; D013385:Succinate Dehydrogenase