title: Effects of DNase production, plasmid size, and restriction barriers on transformation of Vibrio cholerae by electroporation and osmotic shock.
abstract: Attempts to transform wild type strains of V. cholerae with plasmid DNA by traditional osmotic shock methods were not successful. A mutant of V. cholerae that was deficient in extracellular DNase was transformed with plasmid DNA by osmotic shock, demonstrating directly that extracellular DNase is a major barrier to transformation of V. cholerae. Transformation of wild type and DNase-negative strains of V. cholerae was accomplished by electroporation. Efficiency of transformation by electroporation increased with field strength, decreased with plasmid size, and was relatively insensitive to changes in the electrolyte composition of the buffer as long as isotonic sucrose was present. Host-controlled modification/restriction systems also affected transformation efficiency in V. cholerae.
authors.affiliation: Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
authors.forename: H
authors.initials: H
authors.lastname: Marcus
authors.forename: J M
authors.initials: JM
authors.lastname: Ketley
authors.forename: J B
authors.initials: JB
authors.lastname: Kaper
authors.forename: R K
authors.initials: RK
authors.lastname: Holmes
mesh_terms: D002463:Cell Membrane Permeability; D003851:Deoxyribonucleases / Q000096:biosynthesis*; D004560:Electricity; D009997:Osmotic Pressure; D010957:Plasmids; D014169:Transformation, Bacterial; D014734:Vibrio cholerae / Q000201:enzymology / Q000235:genetics*
chemical_list: D003851:Deoxyribonucleases