Morphological and cytoenzymatic characterization of haemocytes of the venus clam Chamelea gallina.
A morphological and enzymatic characterization of Chamelea gallina haemocytes was carried out as a prerequisite for further studies on venus clam immunobiology. Two main types of circulating haemocytes were identified (1) hyalinocytes (79.2%), agranular cells with a central nucleus surrounded by a little cytoplasm, and (2) granulocytes (16.5%), smaller granular cells with smaller nuclei. Small cells with a strongly basophilic nucleus and a thin layer of peripheral cytoplasm, probably undifferentiated blast cells (4.3%), were also observed. Both granulocytes and hyalinocytes can assume a spreading or round morphology. The enzymatic activities of haemocytes were also investigated. Some of the granulocytes and hyalinocytes were positive for hydrolytic enzymes, suggesting a role for these cells in phagocytosis; no oxidative enzymes were detected in C. gallina haemocytes. Granulocytes and hyalinocytes can easily adhere to the substratum and exhibit a low phagocytosis activity towards foreign particles (6.3%), whereas the fraction of cells containing ingested material significantly increased after pre-incubation of test particles with cell-free haemolymph, which suggests the presence of opsonin(s) in the haemolymph.
Pampanin
Daniela M
DM
Department of Biology, University of Padova, Italy. pampanin@ibm.ve.cnr.it
Marin
M Gabriella
MG
Ballarin
Loriano
L
D000818:Animals; D049872:Bivalvia / Q000166:cytology*; D006434:Hemocytes / Q000166:cytology* / Q000201:enzymology* / Q000648:ultrastructure; D006867:Hydrolases / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010587:Phagocytosis
D010088:Oxidoreductases; D006867:Hydrolases