title: Genetic Evidence for Plasmid-Linked Lactose Metabolism in Streptococcus lactis subsp. diacetylactis.
abstract: It has been previously observed that loss of plasmid pGK4101 occurred concomitantly with loss of lactose-fermenting ability in Streptococcus lactis subsp. diacetylactis 18-16. Transfer of this 41-megadalton plasmid to LM0230, a lactosenegative (Lac) strain of S. lactis, required cell-to-cell contact and resulted in a conversion of LM0230 to the Lac phenotype. This confirms the linkage of lactose-fermenting ability to the 41-megadalton plasmid in S. lactis subsp. diacetylactis and, in addition, demonstrates transfer by a process resembling conjugation in the group N streptococci.
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108.
authors.forename: G M
authors.initials: GM
authors.lastname: Kempler
authors.forename: L L
authors.initials: LL
authors.lastname: McKay