Stacking of three different restriction and modification systems in Lactococcus lactis by cotransformation |
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Authors: | J Josephsen T Klaenhammer |
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Institution: | Department of Food Science, North Carolina State University, Raleigh 27695-7624. |
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Abstract: | Four plasmids encoding restriction and modification (R/M) systems are described that are different in the specificity of their restrictive activity toward the small isometric phage p2 and prolate phage c2. The R/M plasmids were cotransformed into Lactococcus lactis MG1363 with pVS2, encoding resistance to chloramphenicol and erythromycin, to indicate successful transformation events. Analysis of cotransformants showed that three different R/M plasmids could be combined in L. lactis MG1363. The efficiency at which phage plaqued on the transformants decreased as the number of R/M plasmids increased. Some plasmid combinations were unstable suggesting replicon incompatibility. |
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