The distribution of some hydrolytic enzymes in the cells of the digestive gland of certain lamellibranchs and gastropods

Abstract

Five hydrolytic enzymes (acid phosphatase, aryl sulphatase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase, and non‐specific esterase) have been studied histochemically in the cells of the digestive gland of Mytilus edulis, Helix aspersa, and certain other lamellibranchs and gastropods. All the enzymes studied have basically similar distributions. In the digestive cells, the enzymes occur in cytoplasmic granules which are believed to be primary lysosomes; in vacuoles which contain phagocytosed food material; and in vacuoles containing lipofuscin granules, which are the residues of digestive activity. In the basiphil cells of M. edulis, most of the enzymes are localized in a few cytoplasmic granules; non‐specific esterase, however, is found throughout the cytoplasm. In the calcium cells of H. aspersa and the other pulmonate gastropods studied, the enzymes are either in cytoplasmic granules, or distributed diffusely throughout the cytoplasm. Acid phosphatase is also found in the calcium spherules, especially in H. aspersa. In the excretory cells of H. aspersa and the other pulmonates studied, the enzymes are found in granules in the cytoplasm, and in the lipofuscin granules which lie in the vacuoles of these cells.

Cytochemical investigation of the digestive gland of two strombidae species (Strombus gigas and Strombus pugilis) in relation to the nutrition

“…In S. gigas and Strombus pugilis , acid phosphatase localization is more or less the same as arylsulfatase localization. Even of different sizes, the vesicules from the apical third of digestive cells present an activity for both enzymes, confirming that such vesicles are lysosomes or heterolysosomes when their size exceeds 1 μm (Sumner,1969). We also highlighted an acid phosphatase activity in the large granules of the digestive cells.…”

“…In response to the starvation, acid phosphatase is not produced anymore by digestive cells, while arylsulfatase is still present. A similar study on H. aspersa highlighted that individuals can survive 1 year in starvation and that the lysosomal enzyme activity is detected during all the experiment (Sumner,1969). Among the five enzymes followed, only arylsulfatase and acid phosphatase activity decreased or stopped.…”

“…In the prosobranch Nucella lapillus and in the bivalve M. galloprovincialis , it has been detected in heterolysosomes in the middle of the digestive cells, and, locally in some residual bodies (Dimitriadis and Andrews,2000; Robledo et al,2006). Sumner (1969) also reported it detection in “cytoplasmic granules” of M. edulis digestive cells and in the whole cells in H. aspersa . In S. gigas and Strombus pugilis , acid phosphatase localization is more or less the same as arylsulfatase localization.…”

“…In the same species, another study reports an arylsulfatase activity in heterolysosomes of the apical pole and in some lysosomal residual bodies (Robledo et al,2006). Finally a fourth study highlighted the presence of arylsulfatase in “cytoplasmic granules” of the digestive cells in the Bivalve M. edulis and in the pulmonate Helix aspersa (Sumner,1969). In Strombidae, we observed an increasing size of arylsulfatase positive vesicles from the apical pole to the one‐half of the cells.…”

Histopathological Changes Induced by Metaldehyde in Eobania vermiculata (Müller 1774)

“…Most findings are consistent with the hypothesis that the digestive gland epithelium of terrestrial gastropods is composed of three cell types: digestive cells, calcium cells and excretory cells (Babua and SkowronskWendland, 1988;Mersal, 1990;Aioub et al, 2000;Dimitriadis, 2001;Chabicovsky et al 2004 andSnyman et al, 2005). The presence of fourth type, the thin cells, have been documented in H. aspersa, A. reticulatus and E. vermiculata (Sumner, 1965(Sumner, , 1969Walker, 1970;Beshr, 2000 andHamed et al, 2007). The digestive gland of gastropods is concerning with production of digestive enzymes, adsorption of nutrients, endocytosis of food substances, food storage and excretion (Dimitriadis, 2001).…”