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A coelectroporation method for the isolation of cryptic plasmids from Lactococcus lactis
Author(s) -
Corneau N.,
Dubé C.,
LaPointe G.,
Émond É.
Publication year - 2001
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.2001.00952.x
Subject(s) - plasmid , biology , lactococcus lactis , electroporation , microbiology and biotechnology , plasmid preparation , genetics , bacteria , dna , gene , pbr322 , lactic acid
Aims: A coelectroporation method using a marker plasmid for indirect selection of lactococcal plasmids with unassigned functions was evaluated. Methods and Results: Cryptic plasmids were mixed with an erythromycin resistance (Ery r ) marker plasmid and introduced into a recipient strain by electroporation, followed by plasmid extraction of erythromycin‐resistant transformants. By optimizing the ratio between the marker plasmid and the cryptic plasmids, an average of 20% cotransformants was obtained, including combinations of more than one cryptic plasmid. The marker plasmid pSA3 was easily eliminated from the cotransformed cells by subculture without selective pressure. Conclusions: This cotransformation approach reduces the number of colonies that must be screened to find transformants harbouring cryptic plasmids. Significance and Impact of the Study: The method facilitates the isolation of cryptic plasmids, helps in assigning functions to unknown plasmids and allows construction of food‐grade lactococcal strains with new combinations of wild‐type plasmids.