Open AccessCloning of the phospho‐β‐galactosidase gene in Escherichia coli from lactose‐negative mutants of Streptococcus mutans isolated following random mutagenesis with plasmid pVA891 clone banks
Author(s) -
Sato Yutaka,
Yamamoto Yasuhito,
Kizaki Harutoshi,
Kuramitsu Howard K.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05212.x
Subject(s) - plasmid , biology , escherichia coli , transformation (genetics) , mutant , microbiology and biotechnology , mutagenesis , streptococcus mutans , lactose , dna , gene , genetics , bacteria , biochemistry
In order to mutagenize Streptococcus mutans a marker rescue plasmid, pVA891, was employed. The plasmid was ligated with Sau 3AI digested chromosomal DNA fragments from S. mutans GS‐5IS3 and the resultant plasmids were amplified in Escherichia coli . These plasmids were then randomly integrated into the chromosome of strain GS‐5IS3 following transformation. Lactose‐negative transformants were isolated as white colonies on lactose‐BTR‐Xgal agar plates containing erythromycin. Six lactose‐negative mutants representing three different chromosomal sites of integration were isolated from about eight thousand transformants. Mutant chromosomal DNA fragments flanking the plasmids were recovered by a marker‐rescue method in E. coli and exhibited phospho‐β‐galactosidase activity.