Cyanide- and hydroxamate-resistant respiration in Neurospora crassa

Abstract

Strain inl-89601 of Neurospora crassa respires exclusively by means of the mitochondrial cytochrome chain. The respiration of this strain is entirely inhibited by cyanide or antimycin A, the classical inhibitors of cytochrome chain respiration. When this strain was grown in the presence of chloramphenicol, however, two additional terminal oxidases were detected. One of these oxidases is inhibited by substituted hydroxamic acids and has been described previously. The second oxidase was not inhibited by cyanide or hydroxamic acid but was inhibited by azide in the presence of both cyanide and hydroxamic acid. This azide-sensitive respiration was due to a single respiratory pathway with a Ki for azide of 200,uM. A small amount of azide-sensitive respiration was detected in mitochondrial fractions obtained from chloramphenicol-treated cells, and it is likely that the azide-sensitive oxidase is localized in the mitochondrion. The determinants for the azide-sensitive and hydroxamate-sensitive oxidases segregate in a Mendelian manner in crosses and are either unlinked or not closely linked to each other.on August 4, 2020 by guest

Dimorphism in Histoplasma capsulatum: a model for the study of cell differentiation in pathogenic fungi.

“…In fact, when cyanide and SHAM were added together in yeast and mycelial cells to inhibit mitochondrial respiration, subsequent addition of cysteine stimulated oxygen consumption to about 60% of the original rate in the yeast cells, but cysteine had no effect on mycelial cells under the same conditions. The possibility that cysteine would be used up by a third mitochondrial respiratory pathway present in some fungi was excluded (29). The cysteine oxidase activity (assayed as cysteine-dependent oxygen consumption in the presence of cyanide and SHAM) was found only in the high-speed supernatant of the yeast cytoplasmic fraction.…”

Selection of succinic dehydrogenase mutants of Neurospora crassa

“…Symbols: (0) particles from ANT-1 prepared in the presence of 2 mM PMSF; (0) particles from ANT-I prepared without PMSF; (A) particles from SDH-1 prepared in the presence of 2 mM PMSF. 0.134 ± 0.003 (8) SDH-1 Succinate 0.047 ± 0.002 (7) 0.017 ± 0.001 (7) aMitochondria were isolated from 15-h cultures by the method of Edwards and Unger (8). The concentrations of substrates used were: NADH, 0.5 mM; succinate, 10 mM.…”

“…MATERIALS AND METHODS Strains. The ANT-1 strain of N. crassa used in these studies has been described previously (5,8).…”

“…Succinic dehydrogenase was assayed using the reduction of phenazine methosulfate (PMS) and 2,6-dichloroindophenol as described by Baginsky and Hatefi (1). Submitochondrial particles prepared according to Edwards and Unger (8) were activated by incubation at 38°C in the presence of 20 mM succinate for 15 min before assay. Succinate oxidase and NADH oxidase activities were measured on isolated mitochondria as described by Edwards et al (7).…”

Διερεύνηση Της Ανθεκτικότητας Των Φυτοπαθογόνων Μυκήτων Στους Παρεμποδιστές Του Συμπλόκου ΙΙΙ Της Αναπνευστικής Αλυσίδας

“…ηηο πεξηζφηηεξεο ησλ πεξηπηψζεσλ επάγεηαη κεηά ηελ παξεκπφδηζε ηεο θπηνρξσκηθήο αλαπλνήο απφ εμεηδηθεπκέλνπο παξεκπνδηζηέο,. Έηζη, ζηνπο κχθεηεο Ustilago maydis (Ziogas and Georgopoulos,1980) θαη Neurospora crassa (Edwards and Unger, 1978) έγηλε επαγσγή ηεο ελαιιαθηηθήο νδνχ παξνπζία ρισξακθεληθφιεο, ζηε δχκε Hansenula anomala παξνπζία antimycin A (Sakajo et.al., 1991), ζηνλ Nectria haematoccoca παξνπζία azoxystrobin θαη antimycin A (Tsehay, 1998), ζηνλ Pyricularia oryzae παξνπζία antimycin A ή παξαγψγσλ ηνπ κεζνμπαθξπιηθνχ νμένο (Mizunati et.al., 1995), ζηνλ Moniliella tomentosa παξνπζία n-πξνπαλφιεο (Von Derleyden et.al., 1978) θαη ζηνλ Pyricularia (Magnaporthe) grisae παξνπζία SFF126 (Mizunati et.al., 1996;Yukioka et.al., 1998).…”