Classification And Phagocytosis Property Of Haemocytes In The Hyriopsis Schlegeli

The haemocytes of the Hyriopsis schlegeli which were stained purple by Giemsa were observed by light microscope. At the same time the morphology of living haemocytes was also observed. The haemocytes were classified as 6 types based on the characteristics, amount of granule and its relative size, the nucleolus /plasm (N/P) ratio. They are granulocyte, hyalinocyte, serous cell, lymphoid cell, spindly cell and thrombocyte. Scan electron microscope was used to observe ultra-structure of the haemocytes and six kinds of haemocytes were recognized: circular cell, ovoid cell, large round cell, small round cell, spindly cell and fibre cell. Four layers were separated by density gradient. Lymphoid cells stay in the layer of 10-20% Percoll extract, hyalinocyte, spindly cell and thrombocyte in 20-30% Percoll extract, granulocyte in 30-40% Percoll extract and serous cell in 40-50% Percoll extract.The dynamic variation of the haemocytes was observed in vivo under the LEICA DM5000 B Microscope, namely, the morphology of haemocytes dipped on the slides underwent manifest changes for a short time. The shapes of hemocytes just taken out from the shell were all round-shape and most of them formed pesuclopods after 1-2 minutes. About 30 minutes later, the pesuclopods withdraw and haemocytes became round again. An important result through continue observation shows that the hyalinocyte and the spindly cell can transform each other. The spindly cell transform to hyalinocyte was completed about 1 hour. The degranulation from one side of cell body was a voluntary and harmless process. The granules would be dissociative and actionless after being released out of haemocytes. All the haemocytes began to die and disintegrate within 1h to 1.5h.Phagocytosis property was evaluated by the analysis of the phagocytosis of haemocytes against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Aeromonas hydrophila. The results showed that phagocytosis can be divided into two modes. One mode is that haemocyte extends pseudopodia of filament or sheet shape, and the other is that haemocyte morphology changes and forms denting. Haemocytes from H. schlegeli of different ages have different recognition of bacteria and phagocytic activity. There is a great effect on the phagocytosis rate to A. hydrophila (P<0.05) but not the other three bacterias. The adsorptive rate is not affected on the four kinds of bacterias, but there is a great impact on phagocytic index and adsorptive index. In general, the phagocytic activity of haemocyte to the four bacterias varied from different ages. Phagocytosis activity of H. schlegeli of 1 -year old is the lowest and is the highest in the 4-year old shell. The phagocytosis activity increased with the growing from age 1 to 4 but declined from age 4 to 6.The location of peroxidase (POD) was observed under light microscope according to blue or brown in the haemocytes through benzidine and hydrogen peroxide method. The results showed that all kinds of haemocytes except lymphoid cell have POD activity. I type of granulocyte and serous cell have higher POD activity than II type of granulocyte, hyalinocyte and spindly cell.