Objective To optimize and simplify the survey method of Oncomelania hupensis snails in marshland endemic re-gions of schistosomiasis,so as to improve the precision,efficiency and economy of the snail survey. Methods A snail sam-pling strategy(Spatial Sampling Scenario of Oncomelania based on Plant Abundance,SOPA)which took the plant abundance as auxiliary variable was explored and an experimental study in a 50 m×50 m plot in a marshland in the Poyang Lake region was performed. Firstly,the push broom surveyed data was stratified into 5 layers by the plant abundance data;then,the required numbers of optimal sampling points of each layer through Hammond McCullagh equation were calculated;thirdly,every sample point in the line with the Multiple Directional Interpolation(MDI)placement scheme was pinpointed;and finally,the compari-son study among the outcomes of the spatial random sampling strategy,the traditional systematic sampling method,the spatial stratified sampling method,Sandwich spatial sampling and inference and SOPA was performed. Results The method(SOPA) proposed in this study had the minimal absolute error of 0.2138;and the traditional systematic sampling method had the largest estimate,and the absolute error was 0.9244. Conclusion The snail sampling strategy(SOPA)proposed in this study obtains the higher estimation accuracy than the other four methods.

Objective: To investigate the relationship between the melatonin and the development of testicle in rabbits. Methods: Thirty male rabbits (unreach puberty) were randomly divided into 2 groups:15 were actively immunized with melatonin and complete antigen, which was successfully synthesized through Mannich reaction by combining melatonin with BSA, the other 15 were taken as controls.The specific antibodies of rabbits were detected by ELISA and RIA.The serum testosterone(T) and luteinizing hormone(LH) were detected by RIA, the mass of testicle or epididymis and the number of sperm were measured. Results: The serum T and LH concentration in experiment group were significantly lower than that in the control group.The mass of testicle or epididymis and the number of sperm in experiment group were also significantly lower than that in the control group. Conclusion: The results suggest that the immunization of melatonin can block the development of testicle in male rabbits.