Lactose negative and copper sensitive (Lac-/Cus) mutants of Lactococcus lactis subsp. lactis MCL64 were isolated after extended incubation periods at 32ºC and 37ºC. A 30.0 kb plasmid was absent in all Lac-/Cus mutants. These results showed that lactose metabolism and copper resistance were linked to the 30.0 kb plasmid in strain MCL64. Using MCL64 as a donor, the 30.0 kb plasmid transferred into Lac-/Cus recipient strains P81 and MCL64-90 with the frequencies of 4.1x10-5- 8.2x10-3 per donor cell, respectively. All transconjugants were found to be of a Lac+/ Cur phenotype.
AKÇELİK, MUSTAFA (2001) "Identification of a Lactose Utilization and Copper Resistance Plasmid in Lactococcus lactis subsp. lactis MCL64," Turkish Journal of Veterinary & Animal Sciences: Vol. 25: No. 5, Article 23. Available at: https://journals.tubitak.gov.tr/veterinary/vol25/iss5/23