Genetic and physical characteristics of an enterotoxin plasmid
- 1 December 1975
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 124 (3) , 1240-1247
- https://doi.org/10.1128/jb.124.3.1240-1247.1975
Abstract
We are engaged in the genetic and physical characterization of an enterotoxin (Ent) plasmid, Ent P307, which contains genes for the production of a hear-labile and a heat-stable enterotoxin. We are using an Escherichia coli K-12 strain, 711 (P307), constructed by S. Falkow, which contains no other plasmids besides Ent P307. Our genetic studies have shown that the plasmid is incompatible with the sex factor F, both in the integrated (Hfr) and the autonomous (F-prime) state. Ent P307 can thus be assigned to incompatibility group FI. An R factor, R386, which belongs to the same incompatibility group, was also found to be incompatibile with Ent P307, whereas five other R factors belonging to different incompatibility groups were compatible with Ent P307. In the presence of Ent P307, conjugal transfer and sensitivity to a male-specific phage of a derepressed F-like R factor, R1drd19, were repressed. Ent P307 is, thus, finO+. Presumably, it also causes repression of its own transfer genes since conjugal transfer of Ent P307 could not be demonstrated. Unlike F, it does not restrict the growth of female-specific phage phiII. From physical studies on extracted deoxyribonucleic acid, the molecular weight of Ent P307 was determined to be 54 X 10(6). By electron microscope heteroduplex analysis, the plasmid was found to be homologous with F in four regions, encompassing about half of its length. One long region and two short ones contain genes for conjugal transfer; the other short region carries genes for replication and incompatibility.Keywords
This publication has 28 references indexed in Scilit:
- Electron microscope heteroduplex studies of sequence relations among plasmids of Escherichia coli: IX. Note on the deletion mutant of F, FΔ(33–43)Journal of Molecular Biology, 1974
- Polynucleotide Sequence Relationships among Plasmids of the I Compatibility ComplexJournal of General Microbiology, 1974
- Interactions between the surface exclusion systems of some F-like plasmidsGenetics Research, 1974
- The Enterotoxin Plasmids of Escherichia ColiThe Journal of Infectious Diseases, 1974
- Electron microscope heteroduplex studies of sequence relations among plasmids of Escherichia coli: II. Structure of drug resistance (R) factors and f factorsJournal of Molecular Biology, 1973
- THE GENETICS OF TRANSMISSIBLE PLASMIDSAnnual Review of Genetics, 1972
- Electron microscope heteroduplex studies of sequence relations among plasmids of Escherichia coliJournal of Molecular Biology, 1972
- Non-chromosomal antibiotic resistance in bacteria: II. Molecular nature of R-factors isolated from Proteus mirabilis and Escherichia coliJournal of Molecular Biology, 1970
- Studies on Escherichia coli sex factors: I. Specific labeling of F'Lac DNAJournal of Molecular Biology, 1968
- A BACTERIOPHAGE CONTAINING RNAProceedings of the National Academy of Sciences, 1961