多聚酶链反应鉴别致病性与非致病性的溶组织内阿米巴虫株

POLYMERASE CHAIN REACTION IN IDENTIFICATION OF PATHOGENIC AND NONPATHOGENIC ENTAMOEBA HISTOLYT1CA ISOLATES

多聚酶链反应是体外DNA增殖的新技术。在多聚酶、dNTP和引物的参与下在数小时内使特异性的DNA顺序大量增殖。用B、C、G、T4株溶组织内阿米巴的DNA增殖30周期后,作凝胶电泳分析,发现致病性虫株的引物不能使B、C、G、T虫株的DNA增殖,凝胶电泳不出现条带;而非致病性虫株的引物能使B、C、G、T虫株的DNA增殖,凝胶电泳出现特异性条带。用辣根过氧化物酶标记致病性虫株DNA探针与B、C、G、T的DNA进行斑点杂交呈阴性反应;而用非致病性虫株DNA探针与B、C、G、T的DNA斑点杂交呈阳性反应。实验结果显示B、C、G、T为非致病性虫株,与同工酶分析一致。多聚酶链反应是鉴别致病性和非致病性溶组织内阿米巴虫株的高特异性和敏感性方法,为从分子生物学研究溶组织内阿米巴的致病机理提供一新技术。

The polymerase chain reaction (PCR) is an in vitro DNA amplification procedure. With the participation of polymerase, dNTP and their primers, specific DNA of known sequences increased greatly in a few hours. Four strains (B, C, G, T) of E. histolytica DNA were used and PCR repeated for 30 cycles. The PCR products were put to gel eleotrophoresis. Results showed that primers for pathogenic strains did not amplify DNA from B,C, G, T strain, and no specific band was observed on gel eleotrophoresis. But primers specific for nonpathogenio strains amplified DNA from B, C, G, T strain, and a specific band was observed on gel analyses. Horseradish peroxidase-labelled pathogenic strain DNA probes did not react with PCR products of B, C, G, T strains; on contrary, nonpathogenio probes reacted, demonstrating that B, C, G, T belonged to nonpathogenio strains. These results corresponded to isoenzyme analyses. PCR is a highly sensitive and specific method for identification of pathogenic and nonpathogenio isolates of E. histolytica. It provides a new method for studying the pathogenioity of E. histolytica on a molecular basis.