Presence of heterogeneous peroxisomal populations in the rat nervous tissue |
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Authors: | AM Cimini I Singh S Farioli-Vecchioli L Cristiano MP Cerú |
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Institution: | 1. Department of Basic and Applied Biology, University of L’Aquila, via Vetoio 10, 67010 Coppito L’Aquila, Italy;2. Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA;3. Department of Cellular and Developmental Biology, University of Rome, Rome, Italy |
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Abstract: | Peroxisomes were purified from the nervous tissue of 14-day-old rats by means of a Nycodenz gradient. Peroxisomal enzymes exhibited different sedimentation patterns: dihydroxyacetone phosphate acyl-transferase equilibrates at 1.142 g/ml together with the first peak of catalase; palmitoyl-CoA oxidase and d-amino acid oxidase activities are mainly recovered at 1.154 g/ml; the second peak of catalase is found at 1.175 g/ml. Morphological and semi-quantitative analyses of immunogold-labelled peroxisomes reveal profound heterogeneity of the particles. Very small (=0.2 μm diameter), electron dense vesicles containing catalase or thiolase, but devoid of other tested enzymes, are preferentially found in the light region, together with larger (>0.2 <0.3 μm) and less electron dense palmitoyl-CoA oxidase-positive peroxisomes. At intermediate density (1.154 g/ml) peroxisomes of more uniform size (0.25–0.27 μm), containing palmitoyl-CoA oxidase or thiolase with or without catalase are preferentially found. This population extends toward the densest region of the gradient, where very large d-amino acid oxidase-containing peroxisomes are also found. In this region, smaller peroxisomes, often polymorphic, which are catalase- and thiolase-positive and d-amino acid oxidase/palmitoyl-CoA oxidase-negative, are also observed. The possibility that the heterogeneity of neural peroxisomes may reflect both cellular heterogeneity and ongoing peroxisomal biogenesis is discussed. |
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Keywords: | Peroxisome Central nervous system Peroxisomal biogenesis Peroxisomal disorder Brain Glia (Rat) |
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