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Accueil du site → Master → Etats Unis → 1979 → Resolution of the subcellular components of cyanide insensitive and sensitive respiration in a durum wheat

University of Arizona (1979)

Resolution of the subcellular components of cyanide insensitive and sensitive respiration in a durum wheat

Goldstein, Alan H.

Titre : Resolution of the subcellular components of cyanide insensitive and sensitive respiration in a durum wheat

Auteur : Goldstein, Alan H.

Université de soutenance : University of Arizona

Grade : Master of Science (MS) 1979

Résumé
Polarographic measurements of mitochondria isolated via differ ential centrifugation from the germ of durum wheat seedlings showed that the ratio of antimycin-A insensitive to total respiration fell from 0o32 to 0.12 at 12 through 64 hrs. of development« Further purification R of the initial mitochondrial pellet on a linear Percoll density gradi ent separated the mitochondria into two bands of physiologically dis tinct activity. Based on the usual respiratory criteria5 these organelles were qualitatively similar to those of the crude pellet, however no antimycin-A insensitive component of respiration was ob served in either mitochondrial gradient band through 64 hrs. Antimycin-A insensitive respiration could be restored exclusively to the upper band of mitochondria by the addition of linoleic acid and this activity was inhibited either by salleyIhydroxamic acid (SHAM) or propyl gallate, a known lipoxygenase inhibitor. Likewise, addition of linoleic acid to the crude pellet elicited a 4 to 5 fold respiration increase. This 0^ consumption was insensitive to antimycin-A and in hibited by either propyl gallate or SHAM. Electron microscopic examina tion revealed that only the lower gradient band contained purified mitochondria which in turn lacked ability to oxidize linoleic acid. These data suggest that in vitro antimycin-A insensitive respiration in wheat seedlings is the result of lipoxygenase activity not directly associated with purified mitochondria.

Mots clés : Durum wheat. ; Plants — Respiration. ; Mitochondria.

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