A Classification of Molluscan Hemocytes Based on Functional Evidences

Morphofunctional Study of the Haemocytes of the Bivalve MolluscMytilus galloprovincialis with Emphasis on the Endolysosomal Compartment.

“…In the present work bacterial and algal cells have been observed within phagosomes of granulocytes thus stressing the importance of haemocyte phagocytosis in nutrition and the close linkage between feeding and internal defence (Cheng 1981;Bayne 1990). The fact that some of the granulocytes showthe presence of phagosomescontaining digestive cell residual bodies, that could be discharged by digestive cells and subsequently interiorized by haemocytes during their diapedesis (Fletcher and Cooper-Willis 1982), supports the idea of these cells having an active role in the excretion of non-degradable digestion end products (Cheng 1984;Bayne 1990). Alternatively the phagocytosis of digestive cell residual bodies could also be related to the resorption of degenerating and necrotic digestive cells during the normal phasic activity of the digestive epithelium (Owen 1972;Cajaraville et al 1991), thus accounting for the recycling of digestive epithelial cells.…”

“…In general, in earlier ultrastructural studies a considerable emphasis has been placed on the use of morphological features to classify bivalve haemocytes (Cheng 1984;Rasmussen et al 1985;Auffret 1988;1989). Nevertheless, the classification of bivalve haemocytes is still a matter of debate (Rasmussen et al 1985;Auffret 1988;Friedl et al 1988).…”

Changes induced by two strains of Vibrio splendidus in haemocyte subpopulations of Mya arenaria, detected by flow cytometry with LysoTracker

“…Interspecies variability and methodological differences in specimen collection and processing have been considered the principal reasons for the current lack of consensus on the actual number of distinct haemocytic subpopulations that can be discerned morphologically (see reviews in Cheng 1981, 1984, Auffret 1988, Hine 1999. There is general agreement, however, that bivalve haemocytes can readily be classified into at least 2 morphologically distinct groups, namely the granulocytes, which tend to be larger and contain cytoplasmic granules, and hyalinocytes (or agranulocytes), which tend to be smaller and contain fewer or no granules.…”

Light and Electron Microscopical Localization of Lysosomal Acid Hydrolases in Bivalve Haemocytes by Enzyme Cytochemistry.

“…In the same cell types there are usually other granules which lack acid hydrolases. Two main cell types are distinguished in the haemolymph of several bivalve molluscs: the non-granular hyalinocytic haemocyte and the granule-containing granulocytic haemocyte [2,3,7,10,30]. These haemocytes constitute the main internal defense system in molluscs, which is brought about by humoral factors and mainly by phagocytosis and cell-mediated cytotoxicity [1].…”