Open AccessMolecular genetics of Streptococcus thermophilus
Author(s) -
Mercenier Annick
Publication year - 1990
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.1574-6968.1990.tb04879.x
Subject(s) - streptococcus thermophilus , lysogenic cycle , biology , plasmid , genetics , streptococcus salivarius , horizontal gene transfer , gene , cloning (programming) , microbiology and biotechnology , genome , bacteria , bacteriophage , escherichia coli , streptococcus , lactobacillus , computer science , programming language
The metabolism and genetics of Streptococcus thermophilus (presently Streptococcus salivarius ssp. thermophilus ) have only been investigated recently despite its widespread use in milk fermentation processes. The development of recombinant DNA technology has allowed impressive progress to be made in the knowledge of thermophilic dairy streptococci. In particular, it has permitted a careful analysis of phenotypically altered variants which were derived from a mother strain by plasmid or chromosomal DNA reorganization. While natural phage defense mechanisms of S. thermophilus remain poorly documented, information on the bacteriophages responsible for fermentation failures has accumulated. The lysogenic state of two S. thermophilus strains has also been demonstrated for the first time. Gene transfer techniques for this species have been established and improved to the point that targeted manipulation of their chromosomal determinants is now feasible. Cloning and expression vectors have been constructed, and a few heterologous genes were successfully expressed in S. thermophilus . The first homologous genes, involved in carbohydrate utilization, have been cloned and sequenced, shedding some light on the molecular organization of key metabolic steps.