Environmental prognostics: an integrated model supporting lysosomal stress responses as predictive biomarkers of animal health status.

Effects of oil on digestive cells in mussels: Quantitative alterations in cellular and lysosomal structure

Latent beta-glucuronidase and glucosaminidase activities have been demonstrated in small cytoplasmic particles, which may possibly be primary lysosomes, as well as some larger granules of the digestive cells of the common mussel. Latency was indicated by increased staining of these structures following incubation in buffer at pH 4.5 at 37 degrees C. The exposure of mussels to temperatures of 25-28 degrees C over a period of four days induced a significant decrease in the latency of lysosomal glucosaminidase. Thermal death produced labilization of lysosomes although selective release of hydrolase activity was indicated by the differential latency of glucosaminidase and glucuronidase. The injection of hydrocortisone induced a significant increase in latency in stressed animals, indicating that the stress response involved changes in structure and function of membranes.

Cytochemical demonstration of latency of lysosomal hydrolases in digestive cells of the common mussel, mytilus edulis, and changes induced by thermal stress.

INTRODUCTIONMarine bivalve molluscs have in recent years attracted considerable attention for a variety of reasons, not least of which is their importance as a source of food for man. Much of this research has concentrated on studies of reproduction; Mytilus viridis (India: Nagabhushanam & Mane, 1975), M. edulis aoteanus and Aulacomya maoriana (New Zealand: Kennedy, 1977);Choromytilus meridionalis and Aulacomya ater (South Africa: Berry, 1978); Mytilus (= Perna) perna (Brazil: Lunetta, 1969); M. edulis planulatus (Australia: Wilson & Hodgkin, 1967); Mytilus californianus and M. edulis (U.S.A.: Hines, 1979); Mytilus galloprovincialis (France: Lubet, 1959) and M. edulis (U.K.: Chipperfield, 1953; Seed, 1975; Bayne et al. 1978). A review of the literature revealed that in the majority of studies cytology was used as a descriptive tool for the ‘staging’ (Chipperfield, 1953; Lubet, 1957; Seed, 1975, 1976) of the developing gametes and certain anomalies were apparent with regard to the nomenclature of the connective tissue matrix of the mantle lobes.

Aspects of Gametogenesis in the Marine Mussel Mytilus Edulis L.

Autophagic and lysosomal reactions to stress in the hepatopancreas of blue mussels.

Histochemical studies of the digestive gland of Lymnaea truncatula have revealed features of the normal digestive processes in which at least 3 cell types are involved: digestive cells, mucus cells and basiphil cells. An intracellular vacuolar digestive system containing lysosomal enzymes appears to operate in the digestive cells. Parasitization by Fasciola hepatica evokes considerable structural and histochemical changes in the host digestive gland. There is, in general, increased cellular vacuolation together with increased lysosomal enzyme activity. The overall effect appears to be an increase in intracellular digestive processes, including autolysis, and it is suggested that this may be a consequence of the host attempting to maintain its nutritional requirements under parasitic stress. Starvation of un-infected specimens induces structural and histochemical changes which closely resemble the effects of parasitization.

Histochemical changes in the digestive gland of Lymnaea truncatula infected with Fasciola hepatica.

The cyctochemical localizations of a number of lysosomal hydrolases have been examined in Littorina littorea, Littorina saxatilis and Littorina neritoides. Reactivity for these enzymes is associated with granular and vacuolar components in the digestive cells, which are presumed to be lysosomes. Seasonal changes in staining intensity in L. littorea appear to be related to the summer growth and winter maturation phases. Invasion of the digestive gland of L. littorea by larval trematodes induces distributional changes in lysosomal hydrolases, which may be related to autophagic and autolytic activities. The distribution of these enzymes in the larval teguments and caecal cells is also described.

The cytochemical localization of lysosomal hydrolases in the digestive cells of littorinids and changes induced by larval trematode infection

Histochemical studies have revealed hydrolytic enzyme activity in the redial tegument and caecal epithelium of Fasciola hepatica. A number of the hydrolases are known to be lysosomal marker enzymes and it is thought that they may be involved in intracellular digestion. The larval stages have also been shown to be reactive for succinate dehydrogenase and phosphorylase, but not for glucose-6-phosphatase.

M. N. Moore

Papers

Histochemical changes in the digestive gland of Lymnaea truncatula infected with Fasciola hepatica.

The cytochemical localization of lysosomal hydrolases in the digestive cells of littorinids and changes induced by larval trematode infection

A histochemical study of the rediae and cercariae of Fasciola hepatica.