title: Cytochrome abnormalities and cyanide-resistant respiration in extranuclear mutants of Aspergillus nidulans.
abstract: The cytochrome spectra of two extranuclear mutants of Aspergillus nidulans and the double-mutant recombinant formed from them have been examined both at room temperature and at the temperature of liquid N2 and compared with those of the wild-type strain. The oligomycin-resistant, slow growing mutant contained an increased amount of cytochrome c without any loss of cytochromes b and a,a3. The cold-sensitive mutant, apparently normal when grown at 37 C, showed an increased amount of cytochrome c and a partial loss of cytochromes b and a,a3 when grown at 20 C. A combination of these effects was observed in the double-mutant recombinant. Cyanide-resistant respiration was present in both mutant strains and in the recombinant at much higher levels than in the wild-type strain. In the oligomycin-resistant mutant, this was usually present together with cyanide-sensitive respiration, whereas in the cold-sensitive mutant and recombinant grown at 20 C cyanide-resistant approached 100%. Inhibitor and growth yield studies indicated that the cyanide-resistant pathway was not used by the cold-sensitive mutant during growth at 20 C.
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D001233:Aspergillus nidulans / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D003486:Cyanides / Q000494:pharmacology; D003580:Cytochromes / Q000096:biosynthesis*; D004352:Drug Resistance, Microbial; D005111:Extrachromosomal Inheritance; D006877:Hydroxamic Acids / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation; D009840:Oligomycins / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011995:Recombination, Genetic; D013696:Temperature
chemical_list: D003486:Cyanides; D003580:Cytochromes; D006877:Hydroxamic Acids; D009840:Oligomycins; D000968:Antimycin A