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Journal of Bacteriology Oct 1992
Review
Topics: Bacteria; Conjugation, Genetic; DNA Transposable Elements; DNA, Circular; R Factors; Recombination, Genetic
PubMed: 1328149
DOI: 10.1128/jb.174.19.6005-6010.1992 -
Journal of Bacteriology Nov 1975Plasmid incompatibility was studied in Escherichia coli K-12. By double-antibiotic selection, clones were constructed that carried the two R-factors R1 and R100, both...
Plasmid incompatibility was studied in Escherichia coli K-12. By double-antibiotic selection, clones were constructed that carried the two R-factors R1 and R100, both belonging to the compatibility group FII. After release of the selection pressure, each of the two plasmids was lost at the same rate (8% per generation). Mutants of R-factor R1 showing an increased number of copies per chromosome (copy mutants) were tested for their incompatibility towards R-factor R100. The results indicate that plasmid incompatibility is quantitative and not just a qualitative property. All copy mutants studied affected incompatibility, and there were two classes of mutants: one increasing and one decreasing the incompatiblity exerted towards the test plasmid R100. Evidence is presented that incompatibility is related to the mechanisms that control replication. The implications of such a relation on proposed models for control of replication are discussed. The data do not support the hypothesis that plasmid incompatibility is due to competition for a replicational or segregational site.
Topics: Ampicillin; Anti-Bacterial Agents; Conjugation, Genetic; DNA Replication; DNA, Bacterial; Escherichia coli; Kanamycin; Mutation; Penicillin Resistance; Penicillinase; R Factors
PubMed: 1102525
DOI: 10.1128/jb.124.2.641-649.1975 -
Structure (London, England : 1993) Jun 1995
Review
Topics: Crystallography, X-Ray; Models, Molecular; R Factors; Software
PubMed: 8590014
DOI: 10.1016/s0969-2126(01)00187-3 -
Journal of Bacteriology Jul 1962Mitsuhashi, Susumu (Gunma University, Maebashi, Japan), Kenji Harada, Hajime Hashimoto, Mitsuo Kameda, and Mitsue Suzuki. Combination of two types of transmissible...
Mitsuhashi, Susumu (Gunma University, Maebashi, Japan), Kenji Harada, Hajime Hashimoto, Mitsuo Kameda, and Mitsue Suzuki. Combination of two types of transmissible drug-resistance factors in a host bacterium. J. Bacteriol. 84:9-16. 1962.-When two types of R factor, R(TC) and R (CM.SM.SA), or R(TC) and R (CM), were brought together in a host bacterium by superinfection with both factors, loss of either one or both factors was found. In the imperfectly stable existence of both factors in a host bacterium, both factors were transmitted separately by conjugation. As the result of interaction between the two types of R factor present in a host bacterium, recombinant factors were formed, R(25) (TC.CM.SM.SA) and R(31) (CM.TC). The recombinant factors were able to transfer their resistance by conjugation. They were also transduced as one unit into Escherichia coli K12 by Plke phage in the same fashion as the original R(11) (TC.CM.SM.SA) and R(14) (CM.TC) factors independently isolated from dysenteric patients.
Topics: Bacteria; Bacteriophages; Drug Resistance, Microbial; Escherichia coli; Japan; R Factors
PubMed: 14474716
DOI: 10.1128/jb.84.1.9-16.1962 -
Journal of Bacteriology Nov 1962Sugino, Yoshinobu (Osaka University, Osaka, Japan) and Yukinori Hirota. Conjugal fertility associated with resistance factor R in Escherichia coli. J. Bacteriol....
Sugino, Yoshinobu (Osaka University, Osaka, Japan) and Yukinori Hirota. Conjugal fertility associated with resistance factor R in Escherichia coli. J. Bacteriol. 84:902-910. 1962.-The introduction of the contagious drug-resistance factor, R, into an F(-) strain of Escherichia coli allows the R(+)F(-) strain to mate with F(-)R(-) strains. The chromosome fragment transferred from the R(+) cell is relatively large, comparable to the conjugation between F(+) or Hfr male and F(-) female bacteria. The complex R factor has been analyzed by transduction with phage Pl. Within the R factor, the fertility determinant is inseparable from the determinant responsible for its infectivity, but can be separated from the loci for drug resistance. R thus resembles the category of complex F factors (F-primes) previously analyzed.
Topics: Coliphages; Colistin; Drug Resistance, Microbial; Escherichia coli; F Factor; Fertility; Genetics; Japan; R Factors; Research; Shigella
PubMed: 13979132
DOI: 10.1128/jb.84.5.902-910.1962 -
Journal of Bacteriology Nov 1975The effect of the copy number of plasmid R1drd-19 on cell division of Escherichia coli K-12 was studied in populations growing as steady-state cultures at different...
The effect of the copy number of plasmid R1drd-19 on cell division of Escherichia coli K-12 was studied in populations growing as steady-state cultures at different growth rates, the growth rate being varied by use of different carbon sources. The plasmid copy number was also varied by using copy mutants of the R-factor. The mean cell size was larger in populations carrying an R-factor than in R-factorless populations, an effect that was more pronounced at low growth rates and in populations carrying R-factor copy mutants. The increased cell size was due to formation of elongated cells in a fraction of the population and to an increase in the diameter of all cells. The majority of the cells divided at a normal cell length, but the presence of an R-factor caused some cells to elongate, probably by the uncoupling of chromosome replication and cell division. This can be explained as a competition between the chromosome and plasmid replicons for some replication factor(s), presumably acting on both initiation and elongation of replication. The formation of elongated cells was a reversible process, but occasionally some of the elongated cells reached lengths 20 times that of newborn cells. If cell division did not occur at the normal cell size, the septum was not formed until the cell size was four times that of a newborn cell. When an elongated cell divided, it usually formed a polar septum, thus producing a newborn cell of normal cell length. The ability of plasmid-containing cells to omit one cell division but to retain the capacity of dividing one mass doubling later is compatible with a mechanical model for septum formation and cell division.
Topics: Acetates; Amino Acids; Cell Division; Chromosomes, Bacterial; DNA Replication; DNA, Bacterial; Drug Resistance, Microbial; Escherichia coli; Glucose; Glycerol; Mutation; R Factors; Succinates
PubMed: 1102524
DOI: 10.1128/jb.124.2.633-640.1975 -
Applied and Environmental Microbiology Aug 1981Coliform and fecal coliform populations found in the raw sewages and final sewage effluents of the prairie provinces and the Northwest Territories were examined for...
Coliform and fecal coliform populations found in the raw sewages and final sewage effluents of the prairie provinces and the Northwest Territories were examined for antibiotic resistance and the possession of R factors. It was determined that 8.91% of the total coliform and 10.80% of the fecal coliform populations carried R factors. The following numbers of combinations of R determinants were found: 39 in the Escherichia coli population, 6 in the Citrobacter population, 20 in the Enterobacter populations, 10 in the Klebsiella populations, and 11 in the Aeromonas populations. The maximum number of R determinants transferable simultaneously was seven; organisms with R factors containing determinants for chloramphenicol usually contained determinants for ampicillin. Of the coliform and fecal coliform populations, 2 to 4% were resistant to chloramphenicol in some provinces, and from 17 to 30% of the populations were resistant to three or more antibiotics. It was calculated that coliforms containing R factors in the raw sewage reached population levels of 1.5 X 10(7)/100 ml, and fecal coliforms containing R factors reached population levels of 8.6 X 10(5) ml. Final effluent discharges to the receiving environment contained R factor-containing coliform and fecal coliform populations of 3.1 X 10(4)/100 ml and 5.8 X 10(2)/100 ml, respectively. The incidence of bacteria containing R factors in sewage appears to be increasing with time, and their removal from sewage before discharge to the receiving environment is desirable. Consideration of data on bacteria with R factors should be made in future water quality deliberations and in discharge regulations.
Topics: Anti-Bacterial Agents; Canada; Enterobacteriaceae; Feces; R Factors; Sewage
PubMed: 7283425
DOI: 10.1128/aem.42.2.204-210.1981 -
Antimicrobial Agents and Chemotherapy Jun 1977The mercury and antibiotic resistance of 338 strains of Escherichia coli isolated from hospital patients was determined. Resistance to mercury was found in 58.6% of the...
The mercury and antibiotic resistance of 338 strains of Escherichia coli isolated from hospital patients was determined. Resistance to mercury was found in 58.6% of the isolates. The frequencies of resistance to streptomycin (Sm), tetracycline (Tc), chloramphenicol (Cm), kanamycin (Kan), cephaloridine (Cer), and gentamicin (Gm) were 66.3, 60.3, 56.5, 42.9, 32.1, and 1.5%, respectively. Among the above, 198 mercury- and antibiotic-resistant isolates were selected and tested for their ability to transfer the resistance to susceptible strains of E. coli K-12 and Klebsiella pneumoniae JK5. R plasmids carrying mercury resistance were demonstrated in 89.9% of the mercury-resistant strains of E. coli. Furthermore, R(Hg,Sm,Tc,Cm) plasmids were demonstrated most frequently, followed by R(Hg,Sm,Tc,Cm,Kan), R(Hg,Cm,Kan), and R(Hg,Sm,Tc,Cm,Kan,Cer) plasmids.
Topics: Anti-Bacterial Agents; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Infections; Humans; Mercury; R Factors
PubMed: 327927
DOI: 10.1128/AAC.11.6.999 -
The Journal of Antibiotics Dec 1978Membrane-bound penicillin-binding proteins of an Escherichia coli carrying an R factor which mediated the resistance to penicillins were examined by slab gel... (Comparative Study)
Comparative Study
Membrane-bound penicillin-binding proteins of an Escherichia coli carrying an R factor which mediated the resistance to penicillins were examined by slab gel electrophoresis and fluorography using beta-lactamase inhibitors such as methicillin, clavulanic acid and MC-696-SY2-A, and by affinity chomatography. By fluorography, it appeared that the penicillin-binding proteins of the strain carrying the R factor could not be distinguished from those of the parent strain. In both strains, methicillin had a preferential affinity for penicillin-binding proteins 2 and 3, clavulanic acid for 2 and 4, and MC-696-SY2-A for 1A at the concentration which was needed to inhibit about 75 approximately 80% of beta-lactamase activity of the membrane fraction from a strain carrying an R factor. This with other facts indicates that MC-696-SY2-A has a unique character in the binding to penicillin-binding proteins. By affinity chromatography using cephalexin-CH-Sepharose 4B column, two major cephalexin-binding proteins were detected. Their molecular weights were found to be 110,000 and 32,000, respectively. These two proteins correpsonded to penicillin-binding proteins 1 and 5/6. From these results it was suggested that the R factor had no influence on the penicillin-binding proteins in the E. coli strain examined.
Topics: Bacterial Proteins; Carrier Proteins; Escherichia coli; Membrane Proteins; Penicillin G; Penicillinase; Penicillins; Protein Binding; R Factors; beta-Lactamase Inhibitors
PubMed: 367999
DOI: 10.7164/antibiotics.31.1283 -
Antimicrobial Agents and Chemotherapy Jul 1998We isolated and sequenced a plasmid, named pIP1714 (4,978 bp), which specifies resistance to streptogramins A and B and the mixture of these compounds. pIP1714 was...
Characterization of a staphylococcal plasmid related to pUB110 and carrying two novel genes, vatC and vgbB, encoding resistance to streptogramins A and B and similar antibiotics.
We isolated and sequenced a plasmid, named pIP1714 (4,978 bp), which specifies resistance to streptogramins A and B and the mixture of these compounds. pIP1714 was isolated from a Staphylococcus cohnii subsp. cohnii strain found in the environment of a hospital where pristinamycin was extensively used. Resistance to both compounds and related antibiotics is encoded by two novel, probably cotranscribed genes, (i) vatC, encoding a 212-amino-acid (aa) acetyltransferase that inactivates streptogramin A and that exhibits 58.2 to 69.8% aa identity with the Vat, VatB, and SatA proteins, and (ii) vgbB, encoding a 295-aa lactonase that inactivates streptogramin B and that shows 67% aa identity with the Vgb lactonase. pIP1714 includes a 2,985-bp fragment also found in two rolling-circle replication and mobilizable plasmids, pUB110 and pBC16, from gram-positive bacteria. In all three plasmids, the common fragment was delimited by two direct repeats of four nucleotides (GGGC) and included (i) putative genes closely related to repB, which encodes a replication protein, and to pre(mob), which encodes a protein required for conjugative mobilization and site-specific recombination, and (ii) sequences very similar to the double- and single-strand origins (dso, ssoU) and the recombination site, RSA. The antibiotic resistance genes repB and pre(mob) carried by each of these plasmids were found in the same transcriptional orientation.
Topics: Acetyltransferases; Base Sequence; DNA, Bacterial; Drug Resistance, Microbial; Drug Synergism; Genes, Bacterial; Hydrolases; Molecular Sequence Data; R Factors; Sequence Alignment; Staphylococcus; Virginiamycin
PubMed: 9661023
DOI: 10.1128/AAC.42.7.1794