title: Haemocytes of the clam Tapes philippinarum (Adams & Reeve, 1850): morphofunctional characterisation.
abstract: Tapes philippinarum is a bivalve mollusc of the Pacific Ocean, successfully imported for human consumption into the northern Adriatic Sea (Europe). For better knowledge of its considerable adaptive ability in comparison with similar autochthonous species, a morpho-functional characterisation of its haemocytes was carried out with the establishment of short-term cell cultures (60 min at 25 degrees C). Various methods of cytochemical staining identified four cell types in the haemolymph: granulocytes (48.05% +/- 1.43), hyalinocytes (32.18% +/- 0.99), haemoblasts (18.97% +/- 0.63) and serous cells (0.8% +/- 0.19). The granulocytes, possessing cytoplasmic granules with differing dye affinity, included basophils, neutrophils and acidophils. Such granules stained vitally with Neutral Red, and correspond to lysosomes. Hydrolytic and oxidative enzymes were mainly detectable after stimulation in the presence of yeast cells. Both granulocytes and hyalinocytes were positive for alkaline phosphatase, non-specific esterase, peroxidase, and cytochrome C oxidase, whereas only granulocytes were positive for beta-glucuronidase, acid esterase, and arylsulphatase. Both cell types were competent phagocytes towards yeast and plasma had an opsonising effect. Moreover, the respiratory burst accompanied phagocytosis with superoxide anion production, recognisable through cytoplasmic deposits of formazan after treatment with nitro blue tetrazolium. Haemoblasts were small undifferentiated cells which, due to their morphology and positivity to the anti-CD34 antibody, show the typical features of stem cells. Serous cells, probably arising from Keber's gland and belonging to another differentiation pathway, contained non-sulphate acid mucopolysaccharides and play an important role in early defence mechanisms, taking part in the formation of clots.
authors.affiliation: Department of Biology, University of Padova, Italy. ascilab@civ.bio.unipd.it
authors.forename: F
authors.initials: F
authors.lastname: Cima
authors.forename: V
authors.initials: V
authors.lastname: Matozzo
authors.forename: M G
authors.initials: MG
authors.lastname: Marin
authors.forename: L
authors.initials: L
authors.lastname: Ballarin
mesh_terms: D015720:5'-Nucleotidase / Q000032:analysis; D000115:Acetylesterase; D000135:Acid Phosphatase / Q000032:analysis; D000165:Acridine Orange / Q000737:chemistry; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal; D001192:Arylsulfatases / Q000032:analysis; D001399:Azure Stains / Q000737:chemistry; D049872:Bivalvia / Q000737:chemistry / Q000166:cytology*; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases; D004396:Coloring Agents / Q000737:chemistry; D003576:Electron Transport Complex IV / Q000032:analysis; D005456:Fluorescent Dyes / Q000737:chemistry; D005562:Formazans / Q000737:chemistry; D005966:Glucuronidase / Q000032:analysis; D006434:Hemocytes / Q000737:chemistry / Q000166:cytology*; D007150:Immunohistochemistry / Q000662:veterinary; D007202:Indicators and Reagents / Q000737:chemistry; D007558:Italy; D009499:Neutral Red / Q000737:chemistry; D009195:Peroxidase / Q000032:analysis; D010587:Phagocytosis; D014048:Tolonium Chloride / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D001399:Azure Stains; D004396:Coloring Agents; D005456:Fluorescent Dyes; D005562:Formazans; D007202:Indicators and Reagents; D014048:Tolonium Chloride; D009499:Neutral Red; D009195:Peroxidase; D003576:Electron Transport Complex IV; D002265:Carboxylic Ester Hydrolases; D043182:Carboxylesterase; D000115:Acetylesterase; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D015720:5'-Nucleotidase; D001192:Arylsulfatases; D005966:Glucuronidase; D000165:Acridine Orange