Further Studies on the Localization of Catalase in Yeast Microbodies by Ultrathin Frozen Sectioning

Abstract

The localization of catalase by cytochemical reaction with 3, 3′-diamino-benzidine and by elemental analysis using electron probe microanalysis in Candida cells grown on normal alkanes and in Kheckera cells grown on methanol were examined by ultrathin frozen sectioning, When the glutaralde-hyde-fixed cells were incubated in 3, 3′-diaminobenzidine followed by osmification and ultrathin frozen sectioned, a fairly intense deposition of the DAB reaction product was obtained in the matrix of Candida microbodies. In the case of Kloeckera microbodies, the products were most clearly located in the crystalloid of the matrix. By poststaining with phosphotungstic acid, the membrane structure of the cells were easily recognized without removal of the reaction products in the organelles. When 3-amino-1, 2, 4-triazole, an inhibitor of catalase, was added to the reaction mixture DAB reaction products were not observed in microbodies. The localization of catalase in the microbodies was confirmed by X-ray microanalysis which could detect the characteristic X-ray of the Fe atom originated from catalase. The ultrathin frozen sectioning was found to be useful, especially in yeast cells, for the detection of catalase.