Induction of beta-oxidation enzymes and microbody proliferation in Aspergillus nidulans.
Aspergillus nidulans is able to grow on oleic acid as sole carbon source. Characterization of the oleate-induced beta-oxidation pathway showed the presence of the two enzyme activities involved in the first step of this catabolic system: acyl-CoA oxidase and acyl-CoA dehydrogenase. After isopicnic centrifugation in a linear sucrose gradient, microbodies (peroxisomes) housing the beta-oxidation enzymes, isocitrate lyase and catalase were clearly resolved from the mitochondrial fraction, which contained fumarase. Growth on oleic acid was associated with the development of many microbodies that were scattered throughout the cytoplasm of the cells. These microbodies (peroxisomes) were round to elongated, made up 6% of the cytoplasmic volume, and were characterized by the presence of catalase. The beta-oxidation pathway was also induced in acetate-grown cells, although at lower levels; these cells lacked acyl-CoA oxidase activity. Nevertheless, growth on acetate did not cause a massive proliferation of microbodies in A. nidulans.
Valenciano
S
S
Departamento de Microbiología y Parasitología, Campus Universitario, Facultad de Farmacia, Universidad de Alcalá de Henares, Ctra. Madrid-Barcelona Km 33, E-28871 Alcalá de Henares, Madrid, Spain. mplaborda@alcala.es
Lucas
J R
JR
Pedregosa
A
A
Monistrol
I F
IF
Laborda
F
F
D000085:Acetates / Q000378:metabolism; D000101:Acetyl-CoA C-Acetyltransferase / Q000378:metabolism; D042964:Acyl-CoA Dehydrogenase; D044944:Acyl-CoA Dehydrogenases / Q000378:metabolism*; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000378:metabolism* / Q000648:ultrastructure; D002374:Catalase / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism; D004746:Enoyl-CoA Hydratase / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005649:Fumarate Hydratase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007522:Isocitrate Lyase / Q000378:metabolism; D008830:Microbodies / Q000201:enzymology / Q000502:physiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D019301:Oleic Acid / Q000378:metabolism; D010084:Oxidation-Reduction
D000085:Acetates; D003470:Culture Media; D005227:Fatty Acids; D019301:Oleic Acid; D002374:Catalase; D044944:Acyl-CoA Dehydrogenases; D042964:Acyl-CoA Dehydrogenase; D000101:Acetyl-CoA C-Acetyltransferase; D007522:Isocitrate Lyase; D004746:Enoyl-CoA Hydratase; D005649:Fumarate Hydratase; D005947:Glucose