Developmental potency of larval Schistosoma mansoni, and extraction of its mRNA

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This studies have been undertaken to mainly know way to match larval development in snails thus capable of obtaining mRNA concerning.A new method for isolation of a large number of sporocysts from intestine of infected snails should have process of digestion by autolysis of intestine removed from infected snails for 12-24 hours at 25 'C.When 0.3 % saline was used for implantation of sporocysts from infected to uninfected snails, snails becoming infected were hardly found (0-0.03 %, positive rate). On contrast, 31.3-55.6 % became infected when Schneider's Drosophila medium was used. These findings indicated that foreigh objects such as medium affected infection rate in implantation of sporocysts. Circulating hemocytes from Echinostoma paraensei-infected M line Biomphalaria snails, or from age and size matched control snails, were studied on plastic slides with phase contrast optics. Fully-spread granulocytes,partially-spread granulocytes, hyalinocytes, round cell were consistently present. Among control snails, the relative percentage and estimated number/mm3 of round cells decline significantly with increased snail size, and the corresponding values for both granulocytes increased. By 8 days post infection, infected snails had significantly higher relative percentage of round cells and partially-spread granulo cytes than control. Phagocytic activity of hemocytes was signi-ficantly lower in infected snails than control. These findings indicated that if susceptibility of snail to parasite was affected by hemocyte population, hemocytes could be used to match larval development in snails.