Electron cytochemical studies of Cryptococcus neoformans grown on uric acid and related sources of nitrogen.
Cells of Cryptococcus neoformans grown on xanthine or urate as the sole sources of nitrogen produced numerous, single membrane-bound organelles, deemed to be microbodies. Electron images of these structures showed positive cytochemical staining for catalase and alpha-hydroxy acid oxidase, known marker enzyme activities for microbodies. Microbodies in xanthine and urate-grown cells were cytochemically reactive for the presence of the hydrogen peroxide-producing xanthine and urate oxidases. Molybdenum and phosphorus (elements associated with the cofactor common to nitrogen scavenging enzymes) were detected in the substrate-induced microbodies by X-ray dispersive microanalysis. The single limiting membrane of the substrate-induced microbody was stained by a modified Gomori reaction for the presence of alkaline phosphatase, thereby suggesting the participation of this enzymic activity in the events associated with microbody chemistry.
Research Service, Veterans Administration Medical Center, Kansas City, Missouri 64128.
A M
AM
Fiskin
M C
MC
Zalles
R G
RG
Garrison
D000469:Alkaline Phosphatase / Q000032:analysis; D003455:Cryptococcus neoformans / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure*; D003470:Culture Media; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D008830:Microbodies / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008982:Molybdenum / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D014503:Urate Oxidase / Q000032:analysis; D014527:Uric Acid / Q000378:metabolism*; D019820:Xanthine; D014969:Xanthine Oxidase / Q000032:analysis; D014970:Xanthines / Q000378:metabolism*
D003470:Culture Media; D014970:Xanthines; D019820:Xanthine; D014527:Uric Acid; D010758:Phosphorus; D008982:Molybdenum; D014969:Xanthine Oxidase; D014503:Urate Oxidase; D000469:Alkaline Phosphatase