Presence of non-functional nisin genes in Lactococcus lactis subsp. lactis isolated from natural starters.
Sixty-four lactococcal strains isolated from natural whey starters were screened for the presence of the nisin structural gene by polymerase chain reaction. Seven of them showed a specific PCR product of 320 bp; only two produced antagonistic activity and were resistant to nisin. Southern blots of SmaI-digested DNA from PCR-positive strains hybridized with a nisA probe displayed a location of the gene on different SmaI fragments. Among PCR-positive strains, nisin producers showed specific transcript after reverse transcriptase-PCR, as well as some non-nisin-producing strains. The RT-PCR product could not be shown in one non-nisin-producing PCR-positive strain.
Moschetti
G
G
Instituto di Microbiologia Agraria e Stazione di Microbiologia Industriale, Università degli Studi di Napoli Federico II, Portici, Italy.
Villani
F
F
Blaiotta
G
G
Baldinelli
A
A
Coppola
S
S
D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002875:Chromosomes / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D013294:Lactococcus lactis / Q000235:genetics*; D008892:Milk / Q000382:microbiology; D009561:Nisin / Q000235:genetics*; D016133:Polymerase Chain Reaction
D009561:Nisin