title: Ultrastructural cytology of Basidiobolus haptosporus: morphology and electron cytochemistry of microbodies.
abstract: Vegetative and reproductive cells of Basidiobolus haptosporus possess naturally occurring organelles identified as microbodies. Cells of four other species of the genus contained morphologically indistinguishable organelles. Microbodies were invariably present in cells of the fungi grown on routine mycological media. The constitutive microbody was characterized by a single, intensely electron-opaque crystalloid body which rapidly enlarged to fill the organellar compartment. The microbody then underwent degeneration by an autolytic-like process. Growth of the fungi on xanthine and its catabolites as sole nitrogen sources (but not urea) greatly enhanced the production of new microbodies in which protein was initially accumulated as paracrystalline arrays. These inclusions then underwent reorganization and compaction to form crystalloid bodies. Key enzymes of the purine degradation pathway are believed to be core proteins of the crystalloid. D-amino acid oxidase, alpha-hydroxy acid oxidase, xanthine oxidase and urate oxidase (but not catalase) were detected cytochemically in mature microbodies. Significant levels of phosphorus and molybdenum were present in the microbody crystalloid by X-ray dispersive microanalysis; iron and copper were not detected. The ability of Basidiobolus species to assimilate xanthine and its catabolites might explain their ecological association with the gut and cloacal contents of various amphibia, reptiles and fish.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000032:analysis; D003605:D-Amino-Acid Oxidase / Q000032:analysis; D005658:Fungi / Q000032:analysis / Q000201:enzymology / Q000648:ultrastructure*; D006651:Histocytochemistry; D007770:L-Lactate Dehydrogenase; D045022:Lactate Dehydrogenases; D008830:Microbodies / Q000032:analysis / Q000201:enzymology / Q000648:ultrastructure*; D014503:Urate Oxidase / Q000032:analysis; D014969:Xanthine Oxidase / Q000032:analysis
chemical_list: D000429:Alcohol Oxidoreductases; D045022:Lactate Dehydrogenases; D007770:L-Lactate Dehydrogenase; C071195:D-lactate dehydrogenase; C021379:D-2-hydroxyacid dehydrogenase; D014969:Xanthine Oxidase; D003605:D-Amino-Acid Oxidase; D014503:Urate Oxidase