Objective To study a rapid and sensitive method for determination of virulence-associated genes in O1El Tor,O139,non-O1/non-O139Vibrio cholerae strains.Methods Five pairs of primers were designed respectively ac-cording to cholera toxin sub-unit A gene(ctxA),accessory cholera enterotoxin gene(ace),zonula occludens toxin gene(zot),toxin coregulated pilus A gene(tcpA)and toxR regulatory protein gene(toxR).Multiplex PCR(MPCR)procedures for simultaneously detecting those five genes were established.The gene information of the virulence-associated genes in the Vibrio cholerae strains was obtained through agar gel electrophoresis for products of single amplification of the MPCR.Results The five virulence-associated genes in the positive control Vibrio cholerae O139(MO45strain)could be detected and the results were correct,which could meet the designed request for the method.In the other tested strains(O1EL Tor,O139,non-O1/non-O139)could be detected1to5kinds of the virulence-associated genes.Based on the results of the variety of carried virulence-associated genes,the tested Vibrio cholerae strains could be classified as5kinds of genetypes,and the Vibrio cholerae could be distinguished between toxic and non-toxic strains.The sensitivity of the MPCR approach reached to10 2 cfu/ml.Conclusion This method is rapid,specific and sensitive,which possess great value for practical application.

Objective To detect the spores of sulfite-reducing anaerobes in water. Methods At first the assay on form of the spores was accomplished, then reducing incubation was used to observe the change of the medium color. It indicated that sodium sulfite was reduced if the color of the medium became to black and positive result was able to be determined. Results 54 specimens including pure water, mineral water, secondary drinking water, source water for drinking, swimming pool water and cooling water of air conditioner were assayed. Sulfite-reducing anaerobes were found in 5 specimens of 7 source water samples and the other specimens showed negative results. The detection rate was 9.2%. Conclusion The determination of the spores of sulfite-reducing anaerobes in water was helpful to predict the contaminative degree and situation of water resource, and provide the scientific basis for prevention and control of water pollution.

Objective To study the molecular mechanism of injection with hepatocyte growth factor (HGF) at different doses on angiogenesis in myocardium of dogs with acute myocardial infarction (MI).Methods Sixteen 1.5-year-old male hybrid dogs,weighing 11-13 kg,were divided into 500 ?g HGF treatment group,1 000 ?g HGF treatment group,sham operation group,and no MI interference group,4 dogs in each group.Expressions of VEGF,HGF,CD31,and platelet factor Ⅷ in myocardium of dogs with MI were detected,the number of micro blood vessels was calculated,and correlation between angiogenesis and expression of HGF and VEGF was analyzed in 28 d after the model was established.Results HGF gene therapy could up-regulate the expression of CD31 and VEGF.The expression of CD31 and VEGF mRNA was 0.82 and 0.39 respectively in 1 000 ?g HGF group,and 0.47 and 0.21 respectively in 500 ?g HGF group.The expression of VEGF mRNA was 0.09 and no expression of CD31 mRNA was found in MI group.HGF could increase the angiogenesis in infracted myocardium.The microvascular density was 126.4?10.6,79.8?6.0,and 21.7?2.5/mm2,respectively,in 1 000 ?g HGF group,500 ?g HGF group,and MI group (P