title: Hydrogenosomes in the rumen entodiniomorphid ciliate Polyplastron multivesiculatum.
abstract: The rumen entodiniomorphid ciliate protozoon Polyplastron multivesiculatum was shown, by biochemical and electron microscopic techniques, to possess hydrogenosomes. After differential centrifugation of whole cell homogenates the hydrogenosomal marker enzymes pyruvate:ferredoxin oxidoreductase and hydrogenase were recovered predominantly (61% and 70% of activity respectively) in the large granular fractions that were sedimented by centrifugation for 10(4) g-min (fraction P1) and 10(5) g-min (fraction P2). These subcellular fractions contained membrane-bound organelles that were approximately 0.4-0.6 microns in diameter and which had a mean equilibrium density of 1.22-1.24 g ml-1 after isopycnic centrifugation in sucrose gradients. Malate dehydrogenase (decarboxylating) activity, however, was predominantly non-sedimentable after centrifugation for 6 x 10(6) g-min. Numerous hydrogenosome-like organelles were present in the ectoplasm and endoplasm of the cell. Hydrogenase activity was demonstrated and localized in the protozoan cell using a novel staining procedure with distyryl nitroblue tetrazolium chloride (DSNBT).
authors: Department of Cell and Structural Biology, University of Manchester, UK.
authors: R G
authors: RG
authors: Paul
authors: A G
authors: AG
authors: Williams
authors: R D
authors: RD
authors: Butler
mesh_terms: D000818:Animals; D016798:Ciliophora / Q000201:enzymology* / Q000648:ultrastructure; D006651:Histocytochemistry; D006864:Hydrogenase / Q000378:metabolism*; D008854:Microscopy, Electron; D015388:Organelles / Q000201:enzymology / Q000648:ultrastructure; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D006864:Hydrogenase