Sedimentable hydrogenase activity was demonstrated in cell-free extracts from both zoospores and vegetative growth of the anaerobic rumen fungus Neocallimastix patriciarum. Electron micrographs of the fraction enriched in hydrogenase activity contained finely granular microbody-like organelles, about 0.5 micron in diameter and having an equilibrium density of about 1.2 g X ml-1 in sucrose, 1.12 g X ml-1 in Percoll and 1.27-1.28 g X ml-1 in Metrizamide. These organelles, which are sedimentable at 10(5) g-min, bear no similarity to mitochondria, but are morphologically similar to hydrogen-evolving organelles possessed by certain anaerobic protozoa and termed ‘hydrogenosomes’. Other typical hydrogenosomal enzymes, namely ‘malic’ enzyme, pyruvate:ferredoxin oxidoreductase and NADPH:ferredoxin oxidoreductase, were enriched in the same particle fraction as hydrogenase. The synthesis of pyruvate:ferredoxin oxidoreductase was found to be suppressed when the organism was cultured under an atmosphere of CO2, and an alternative pathway is proposed for growth under these conditions.
Research Article| June 15 1986
Hydrogenosomes in the rumen fungus Neocallimastix patriciarum
Biochem J (1986) 236 (3): 729–739.
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N Yarlett, C G Orpin, E A Munn, N C Yarlett, C A Greenwood; Hydrogenosomes in the rumen fungus Neocallimastix patriciarum. Biochem J 15 June 1986; 236 (3): 729–739. doi: https://doi.org/10.1042/bj2360729
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