OBJECTIVEThe purpose of this study is to construct a pyruvate oxidase gene deficiency variant strain of Streptococcus oralis (S. oralis).

METHODSThe 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.

RESULTSThe authors obtained a pyruvate oxidase gene deficiency variant strain of S. orlis. The catalase activity examination showed that the ability of producing H2 O2 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 H2 O2 quantity of their subcultures was less than that of the negative control.

CONCLUSIONThe construction of the pyruvate oxidase gene deficiency variant strain of Streptococcus oralis is successful.