title: Strongyloides ratti: mitochondrial enzyme activities of the classical electron transport pathway in the infective (L3) larvae.
abstract: Submitochondrial particles prepared from S. ratti L3 larvae exhibited NADH-oxidase (NOX), NADH-ferricyanide reductase (NFR), NADH-cytochrome-c-reductase (NCR), succinate-cytochrome-c-reductase (SCR), and cytochrome-aa3-oxidase activities of 2.1 +/- 0.3, 8.9 +/- 1.3, 0.6 +/- 0.1., 1.0 +/- 0.2 and 1.2 +/- 0.3 nm min-1 mg protein-1 respectively, at 37 degrees C. The NCR and NOX activities were 39.3% and 23.5% of the NFR activity, suggesting the occurrence of a rate-limiting step or bifurcation of the respiratory electron transport (RET) pathway on the oxygen-side of RET-Complex I. The NCR activity was 50% that of cytochrome-aa3-oxidase activity which suggests partitioning of electron flow at the level of RET-Complex III and/or the quinone-function. Antimycin A and rotenone but not 2-thenoyl trifluoroacetone (TTFA) inhibited NCR activity, the EC50 values were 3.6 x 10(-6) M, 3.7 x 10(-7) M, respectively. SCR activity was inhibited by antimycin A (EC50 = 3.8 x 10(-6) M) and TTFA (EC50 = 2.8 x 10(-5) M) but not by rotenone. The results suggest that presence of classical and alternate RET-pathways in S. ratti L3 larvae.
authors.affiliation: School of Biomedical Sciences, Curtin University of Technology, Perth, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Armson
authors.forename: W B
authors.initials: WB
authors.lastname: Grubb
authors.forename: A H
authors.initials: AH
authors.lastname: Mendis
mesh_terms: D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D007700:Kinetics; D007814:Larva; D008928:Mitochondria / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012402:Rotenone / Q000494:pharmacology; D017170:Strongyloides ratti / Q000201:enzymology* / Q000469:parasitology*; D013367:Submitochondrial Particles / Q000201:enzymology; D013384:Succinate Cytochrome c Oxidoreductase / Q000378:metabolism; D013804:Thenoyltrifluoroacetone / Q000494:pharmacology
chemical_list: D009097:Multienzyme Complexes; D012402:Rotenone; D013804:Thenoyltrifluoroacetone; D000968:Antimycin A; D013384:Succinate Cytochrome c Oxidoreductase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; C014227:ferricyanide reductase; D009245:NADH Dehydrogenase; D003576:Electron Transport Complex IV; D014450:Electron Transport Complex III