Microperoxisomes and Catalase-Positive Particles
Improved cytochemical methods for visualizing the peroxidatic activities of catalase (Fahimi 1969) by means of strong alkaline DAB media (Herzog and Fahimi 1974 b, Novikoff and Goldfischer 1968, 1969, Novikoff et al. 1972 a) enabled the identification of catalase-positive particles (CPs) in almost all the mammalian cell types investigated thus far. The organelles are bordered by a single unit membrane and lack a crystalline core within the matrix. The matrix is seen to have a moderate electron density, and a fine granularity becomes more prominent after incubation in DAB media. The size and shape of the organelles vary within a wide range; the smallest organelles are spherical with a diameter of about 0.1 µm (Fig. 40). Other particles are ovoid, and in some cases a rod- or worm-like shape is found. The latter CPs are up to 1 µm long, whereas the small diameter does not greatly exceed 0.1 µm (e.g., in yolk sac visceral epithelium of the mouse, Hruban et al. 1972 a; Harderian gland of the mouse and rat, Böck et al. 1975). In most cases the organelles are round to oval in shape with a diameter of 0.1–0.35 µm (Fig. 48).
KeywordsBrown Adipose Tissue Acid Oxidase Smooth Endoplasmic Reticulum Peroxidatic Activity Harderian Gland
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