الملخص
Objective To evaluate the molluscicidal effect of black plastic mulching in mountainous areas of Yunnan Prov-ince. Methods In Leqiu Village,Nanjian County,Yunnan Province,the terraced fields with Oncomelania hupensis snails were divided into A,B,C,D,E groups,and of which,A,B,C,D groups,as the experimental groups,were administered with sim-ple black plastic mulching for 30 days,60 days,90 days and 120 days respectively;Group E,as the control group,was adminis-tered with 50%niclosamide ethanolamine salt wettable powder spraying. Results In Group C and D(simple black film mulching for 90 days and 120 days),no snails were found after the administration,the average density of living snails decreased by 100%, and the cost of one year was similar to that of the control group. Conclusion The molluscicidal effect of black plastic mulching is good in mountainous areas.
الملخص
Objective To explore the effect of phenol oxidase antigen on liver pathologic change in mice infected with Schistosoma japonicum. Methods 42d-aged adult worms were incubated in RPMI 1640 containing 0.05% sodium phenobarbital for 8 h. The worms were washed three times with PBS (pH 6.8) and homogenized with a Teflon pestle. The homogenate was then centrifuged at 3000 g for 20 min at 4 ℃. Supernatant fractions containing phenol oxidase (PO) were analyzed by means of polyacrylamide gel electrophoresis (PAGE). The rude antigen of PO was obtained by cutting the corresponding gel of PO activities. Three groups were set up to observe whether PO could induce protective immunity: experiment group, adjuvant control group and water control group. On day 42 post infection with (40?1) cercariae of Schistosoma japonicum, the mice were sacrificed to observe liver pathologic changes. Results The liver surface of PO immunized group was rather smooth and the liver color was slightly gray. A few pale nods were seen indistinctly but not clearly. Necrosis and inflammatory cell infiltration were not clear. There were many immature eggs without granuloma reaction. The mean diameter and area of the granuloma in the experiment group were less than those in the control group. There were significant differences among the 3 groups (P