Abstract:

The purpose of this study is to construct a pyruvate oxidase gene deficiency variant strain of Streptococcus oralis ( S . oralis) . Methods : The sopox gene , which was got using polymerase chain reaction (PCR) , and the 130- basepair segment of which was cut down with endonuclease BamHI , and transferred into S . oralis (ATCC10557) by using electrotransformation. The authors obtained a variant strain of S . oralis , and then the catalase activity of the first culture and 3-4 subcultures was examined. Results : The authors obtained a pyruvate oxidase gene deficiency variant strain of S . orlis. The catalase activity examination showed that the ability of producing H2O2 of the variant strain of S . orlis declined , whose catalase activity was between those of the positive control (ATCC10557) and the negative control ( Escherichia coli , JM109) . But the produced H2O2 quantity of their subcultures was less than that of the negative control.Conclusion :The construction of the pyruvate oxidase gene deficiency variant strain of Streptococcus oralis is successful.

Key words: Streptococcus oralis, pyruvate oxidase, homologous recombination, variation