ISSN:
1615-6102
Keywords:
Crystalline inclusions
;
Cytochemistry
;
Glycolate oxidase
;
Glyoxysomes
;
Peroxisomes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Alpha hydroxy acid oxidase activity (using glycolate as substrate) was demonstrated cytochemically in leaf-type peroxisomes, glyoxysomes, and unspecialized peroxisomes of higher plant tissues with the CeCl3 technique in which cerous ions react with enzyme-generated H2O2 to form insoluble, electron-dense cerium perhydroxide. In all peroxisomes examined, reaction product was deposited throughout the matrices. None of the three types of microbody inclusions (crystals, amorphous nucleoids, or fibrillar, threadlike structures) observed in leaftype peroxisomes showed cytochemical reactivity. However, results with crystal-containing peroxisomes of guayule and tobacco leaves indicate an intimate association of glycolate oxidase with the crystals; reaction product was deposited in the spaces between the structural units of the crystal. Prolonged (18- versus 3-hour) incubation with glycolate and CeCl3 were required for reliable cytochemical reactivity in glyoxysomes of castor bean endosperm and unspecialized peroxisomes of barley coleoptile, both of which contain relatively low enzyme activity. The CeCl3 procedure may prove useful for helping identify microbodies observed with the electron microscope as peroxisomes. The lack of significant background deposits, and resolution of reaction product within crystals, illustrate qualities of the CeCl3 procedure superior to those of the ferricyanide-reduction method, which was previously used to localize glycolate oxidase in higher plant microbodies.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01276882
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