title: Inhibition of chlororespiration by myxothiazol and antimycin A in Chlamydomonas reinhardtii.
abstract: Myxothiazol and antimycin A are shown to suppress the oxygen transient previously attributed to the flash-induced inhibition of chlororespiration in Chlamydomonas reinhardtii (Peltier et al. 1987, Biochim Biophys Acta 893: 83-90). However, these two compounds do not affect the photosynthetic electron transport chain as inferred by the insensitivity of the CO2-dependent photosynthetic O2 evolution and of the flash-induced electrochromic effect. Chlorophyll fluorescence induction measurements carried out in dark-adapted cells of a mutant of Chlamydomonas lacking photosystem 1, show that myxothiazol and antimycin A significantly increase the redox state of the photosystem 2 acceptors. We conclude from these results that chlororespiration is inhibited by myxothiazol and antimycin A and that the site of inhibition is located on the dark oxidation pathway of the plastoquinone pool. This inhibition is interpreted through the involvement of a myxothiazol and antimycin A sensitive cytochrome in the chlororespiratory chain.
authors.affiliation: Département de Physiologie Végétale et Ecosystèmes, Centre d'Etudes de Cadarache, 13108, Saint-Paul-lez-Durance, France.
authors.forename: J
authors.initials: J
authors.lastname: Ravenel
authors.forename: G
authors.initials: G
authors.lastname: Peltier