Search results for "Extracellular digestion"
showing 2 items of 2 documents
Effects of cadmium exposure on the ultrastructure of hepatopancreatic cells of Thais haemastoma (gastropoda, prosobranchia)
1993
Abstract Specific histopathological parameters have been proposed as good indicators of heavy-metal pollution. Hence the study of ultrastructural alterations in target organs from sentinel animals after heavy-metal exposure may provide a useful tool in understanding the cellular role in heavy-metal metabolism. The main purpose of this study was the determination of the ultrastructural changes in the different hepatopancreatic-cell types of Thais haemastoma after experimental exposure to cadmium. Specimens of this species from the Gulf of Valencia were exposed to sublethal doses of cadmium during a period of 96 h. The hepatopancreas was excised and prepared in a routine manner for electron m…
Defence Mechanisms and Stem Cells in Holothuria polii and Sipunculus nudus
2009
Holothuria polii (Phylum Echinodermata) and Sipunculus nudus (Phylum Sipuncula) have been used as model systems for studying invertebrate immunity. In the coelomic fluid of Holothuria polii, coelomocytes (i.e. amoebocytes, Type I, Type II, Type III spherule cells) and stem cells are present. After an injection of formalin-fixed sheep erythrocytes into the coelomic cavity, structural modifications in the animal’s, such as the coelomic cavity, stone canal and periesophageal ring were observed. Cellular events observed within the coelomic cavity include the recruitment of a large number of coelomocytes from the haemopoietic areas, phagocytosis carried out by amoebocytes and the formation of br…