The peroxisomes of the hepatopancreas in marine gastropods

Abstract

An ultrastructural study of the peroxisomes was performed in the hepatopancreas of six species of marine gastropods. Peroxisome morphology was described in the basophilic cells and digestive cells of each species. The identification of this organelle was supported by the cytochemical detection of catalase. Large peroxisomes, frequently with a diameter between 1.0 and 1.5 μm, possessing a prominent crystalline nucleoid with hexagonal section were observed in Gibbula umbilicalis and Monodonta lineata basophilic cells. In the digestive cells of the same two species, the peroxisomes usually do not exceed 0.5 μm in diameter and in some of them a small nucleoid was found. A diamond shaped nucleoid was observed in the digestive cell peroxisomes of Patella vulgata and Ocenebra erinacea. In the hepatopancreas of Siphonaria algesirae the peroxisomes also presented a diamond shaped nucleoid. On the other hand, nucleoids were not detected in the basophilic cell peroxisomes of P vulgata, O erinacea and Nucela lapillus. In the peroxisomes of N lapillus digestive cells, typical nucleoids were also not found, but in some of them a dense region attached to the peroxisomal membrane was observed. In general, digestive cell peroxisomes were associated with mitochondria and lipid droplets, while basophilic cell peroxisomes were close to endoplasmic reticulum cisternae, mitochondria, lipofuscin granules or secretion granules.