Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA*
AUTOR(ES)
Cohen, Stanley N.
RESUMO
Transformation of E. coli cells treated with CaCl2 to multiple antibiotic resistance by purified R-factor DNA is reported. Drug resistance is expressed in a small fraction of the recipient bacterial population almost immediately after uptake of DNA, but full genetic expression of resistance requires subsequent incubation in drugfree medium before antibiotic challenge. Transformed bacteria acquire a closed circular, transferable DNA species having the resistance, fertility, and sedimentation characteristics of the parent R factor. Covalently-closed, catenated, and open (nicked) circular forms of R-factor DNA are all effective in transformation, but denaturation and sonication abolish the transforming ability of R-factor DNA in this system.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=426879Documentos Relacionados
- Non-Chromosomal Antibiotic Resistance in Bacteria, III: Isolation of the Discrete Transfer Unit of the R-Factor R1*
- Recircularization and Autonomous Replication of a Sheared R-Factor DNA Segment in Escherichia coli Transformants*
- Transformation and Physical Properties of R-Factor RP4 Transferred from Escherichia coli to Rhizobium trifolii
- Elimination of Resistance Determinants from R-Factor R1 by Intercalative Compounds
- Specific Labeling and Physical Characterization of R-Factor Deoxyribonucleic Acid in Escherichia coli