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Influence of lactococcal plasmid on the specific growth rate of host cells
Author(s) -
Kobayashi M.,
Nomura M.,
Fujita Y.,
Okamoto T.,
Ohmomo S.
Publication year - 2002
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2002.01213.x
Subject(s) - plasmid , lactococcus lactis , biovar , biology , microbiology and biotechnology , strain (injury) , polymerase chain reaction , transformation (genetics) , host (biology) , bacteria , dna , genetics , gene , lactic acid , anatomy
Aims: To investigate a lactococcal plasmid responsible for a reduction in growth rate of its host cell. Methods and Results:Lactococcus lactissubsp.lactisbiovar.diacetylactisDRC1 carries a high number of plasmids. The DRC1 wild‐type strain was found to grow more slowly than a plasmid‐free derivative of DRC1. The plasmids extracted from DRC1 together with anindicator plasmid were cotransformed into the plasmid‐free strain DRC1021. A 7·4‐kb cryptic plasmid, designated pDR1‐1, was found to significantly affect the maximum specific growth rate (µ max ) of the host cell. Polymerase chain reaction (PCR) analysis was carried out in order to detect the presence of pDR1‐1 in the other L. lactis strains. The µ max of the single pDR1‐1‐positive strain was determined to be the same as that of DRC1. Significance and Impact of the Study:These results suggest that pDR1‐1 (or a pDR1‐1‐like plasmid) is a critical factor in the reduction of the µmaxof DRC1, and that its effect on the µmax is significantly greater than that of any other coexisting plasmid.