Drug Resistance of Enteric Bacteria VIII. Chromosomal Location of Nontransferable R Factor in<i>Escherichia coli</i>

Harada, Kenji; Kameda, Mitsuo; Suzuki, Mitsue; Shigehara, Susumu; Mitsuhashi, Susumu

doi:10.1128/jb.93.4.1236-1241.1967

Cited by 28 publications

(8 citation statements)

References 13 publications

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“…Drugs, determination of drug resistance, transmission of R and T-r factors by conjugation, conditions of transduction, and recombination of chromosomal markers were investigated as previously described [9,10].…”

Section: Methodsmentioning

confidence: 99%

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Genetic Properties of a T Factor and T‐r Recombinants

Kameda

Suzuki

Nakajima

et al. 1970

Japanese Journal of Microbiology

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Genetic studies have shown that one of the transfer (T) factors , T95, carries the following genetic properties: autonomous replication (rep+), conjugal transmission (tra+), transmission of the host chromosome (mat+), inhibition of F-mating (ifm+ or fi+), inhibition of superinfection with R factor (irs-), and suppression of phage proliferation (spp-). An Escherichia coli K12 strain carrying T95 factor is insensitive to male phages (f1 and f2). These facts indicated that the T95 factor is a sex factor but different from the F factors. By the interaction between T95 factor and the nontransferable resistance determinants; r21 (tet) for tetracycline resistance and r3 (kan) for kanamycin resistance, recombinants, T-tet, T-kan, and T-tet-kan, factors were obtained. These are capable of conferring drug-resistance and are conjugally transmissible as a single genetic unit. E. coli K12 strains carrying T95 or T-tet factor were insensitive to male phages and T-tet (probably T95) factor was transmitted sexually at about 10-5 transmission frequency after 1 hr of mixed culture. On the contrary, E. coli K12 strains carrying T-kan or T-tet-kan factor were found to become sensitive to male phages and their transmission frequency was 102 to 103-fold higher than that of T-tet factor. As a result of these findings, we concluded that the pili formation of T95 or T-tet factor is in a repressed state but the formation of a recombinant between T95 (or T-tet) and r3 (kan) determinants results in the derepression of pili formation.In previous papers [17,24], we presented three mechanisms involved in the acquisition of transmission of otherwise nontransferable resistance (r) determinants, 1) the resistance determinant which is integrated into the bacterial chromosome is transferred accompanying chromosomal transfer by sex factors such as F, R, and T factors, 2) acquisition of transferability of a nontransferable R factor which exists extrachromosomally, by complementation of episomic elements such as F, R, and T factors, and 3) formation of a recombinant between an r determinant and sex factors, resulting in the formation of F-r, R-r, and T-r factors [8,10,17]. This paper deals with the genetic properties of the T factors and of the recombinant T-r factors. MATERIALS AND METHODSStrains. Derivative strains of Escherichin coli K12 were used. The abbreviations and symbols of various markers were assigned according to the symbols described 339 340 M. KAMEDA ET AL.

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Section: Methodsmentioning

confidence: 99%

“…SM. SA) factor with phage epsilon [7] and is located on the host chromosome, between lac and pro, near lac [9]. or (TC.KM)-resistance, were sensitive to male phages and those carrying nontransferable drug-resistance were insensitive to male phages.…”

Section: Genetic Properties Of T95 Factormentioning

confidence: 99%

Genetic Properties of a T Factor and T‐r Recombinants

Kameda

Suzuki

Nakajima

et al. 1970

Japanese Journal of Microbiology

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“…The F+ (tet) conjugants were capable of transmitting their (tet) determinant by conjugation but the F-(tet) conjugants were not [4]. When E. coli strain carrying the nontransmissible (tet) determinant was infected with F, F', R or T factors, the recombinants F-tet, F'-tet, R-tet and T-tet factors were formed [5,7,11,12,18]. These results strongly suggested.…”

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Formation of Multiple Drug Resistance Factors by Recombination between Transfer Factor and Resistance Determinants

Kameda

Harada

Suzuki

et al. 1972

Japanese Journal of Microbiology

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Drug-resistance(r) determinants, r21(tet), r1(cml), and r11(str.sul), were obtained from R factors, and were capable of conferring resistance to tetracycline, chloramphenicol, and to both streptomycin and sulfanilamide, respectively. They were integrated into the chromosome ofEscherichia coli K12 and nontransmissible by conjugation.As described previously, the recombinant T-tet factor was formed and conjugally transmissible when E. coli K12 r(tet) + was infected with T95 one of the transfer factors. Similarly, the recombinants T-tet.cml and T-tet.str.sul factors were formed by the interaction between T-tet factor and resistance determinants r1(cml) and r11(str.snl), respectively. Subsequently, T-tet.cml.str.sul factor was formed by the recombination between T-tet.cml factor and r11(str.sul) determinant, and T-tet.str.sul.cml factor was produced by the infection of E. coli K12 r1(cml)+ with T-tet.str.sul factor. These recombinants were conjugally transmissible and transduced by phage P1 as one unit. These results strongly suggested the origin of R factors which were capable of conferring multiple resistance and transmissible by conjugation. According to the segregational patterns of resistance determinants by transduction and by conjugal transmission, the genetic structure of T-tet.cml.str.sul factors was established as being circular and the linkage order of the determinants of these factors was described.The resistance determinants in transductants were consistently segregated between a determinant governing tetracycline (TC) resistance and those responsible for resistance to chloramphenicol(CM), streptomycin(SM) and sulfanilamide(SA) in the transduction of R(TC.CM.SM.SA) factor in E group Salmonella with either bacteriophage epsilon [3] or P22 [25]. It was found that the TC resistance determinants, (tet) in transductants were all nontransferable by conjugation and not cured by treatment with acridine dyes [3]. The (tet) determinant in Salmonella was transferred to Escherichia coli K12 strain in cooperation with the F factor. The F+ (tet) conjugants were capable of transmitting their (tet) determinant by conjugation but the F-(tet) conjugants were not [4]. When E. coli strain carrying the nontransmissible (tet) determinant was infected with F, F', R or T factors, the recombinants F-tet, F'-tet, R-tet and T-tet factors were formed [5,7,11,12,18]. These results strongly suggested. that R factors originated from the formation of recombinants between otherwise nontransmissible resistance(r) determinants and sex factors. This paper deals with the formation of recombinant T-r factors resulting in the formation of multiple resistance factors.

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“…SM. SA) factor with phage P22 or epsilon, it was found that the resistance determinants were consistently segregated between the determinant for TC-resistance (tet) and the remaining resistance markers [6,17] and that the tet determinant was integrated into the host chromosome [2,8,9,11]. The nontransferable tet determinant obtained by transduction with phage epsilon was conjugally transferred to an E. coli K12 from Salmonella E strain by cooperation with F', F and the wild type R factor and the recombinants F-tet, F'-tet or R-tet were formed and transmissible by conjugation [7,10].…”

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“…The genetic symbols were described according to Taylor et al [16]. Transduction was conducted in the system of E. coli K12 and phage Plkc, following methods described previously [7,10,11]. A donor strain of F-lac-tet, JE346 F-lac85 was found to be deficient in structural genes lac Y and lac Z.…”

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confidence: 99%