The Genetic Control Colicinogenic Factors E2 I and V

Zwaig, Rosa Nagel de; Antón, Dora N.; Puig, Juan

doi:10.1099/00221287-29-3-473

Cited by 32 publications

(13 citation statements)

References 3 publications

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“…Some loss of F~ viability has also been reported recently by Zwaig et al (1962) in crosses involving lower concentrations of the same Hfr strain, but not with other Hfr strains tested. incubation with a 200-fold excess of HfrH bacteria.…”

Section: (Ii) the Viability Off~ Cells In Mixtures With High Concentrsupporting

confidence: 50%

Cellular damage associated with multiple mating inE. coli

Gross

1963

Genet. Res.

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In crosses in which the ratio of Hfr to F- cells was varied it was found that with one group of Hfr strains the yield of recombinants increased linearly with donor concentration until the number of donor and recipient cells were approximately equal. With other Hfr strains marked deviations from linearity were observed at Hfr: F−ratios greater than 1:5 and in crosses with one particular F−strain the yield of recombinants actually decreased progressively as the Hfr concentration was raised beyond this value. The deviations from linearity observed with this group of strains have been shown to be due to damage to F−cells which mate simultaneously with several Hfr cells.

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Section: (Ii) the Viability Off~ Cells In Mixtures With High Concentrsupporting

confidence: 50%

Cellular damage associated with multiple mating inE. coli

Gross

1963

Genet. Res.

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“…The detergent was added to disperse the fatty acids (when present), and in all media it was used to allow comparisons. M9 medium contained: NH4Cl, 1.0 g; NaCl, 0.5 g; MgSO4 7H2O, 0.25 g; KH2PO4, 3.0 g; and Na2HPO4, 6 g, per liter of distilled water. The pH values of the media were 6.7 to 7.0.…”

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confidence: 99%

Chilling cells enhances the bactericidal action of fatty acids on Escherichia coli

Fay¹,

Farias²

1976

Appl Environ Microbiol

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Preincubation at 0 C considerably increased the bactericidal action of 0.4% nonanoic and decanoic acids on Escherichia coli K-12 154. This lethal effect seemed to be dependent on the media used to grow the bacteria. Stationaryphase cells were more sensitive than those from exponential cultures. A mutant (FA31) resistant to the bactericidal action of "cold shock" and 0.4% decanoic acid was isolated from E. coli FA23 (an E. coli 154 derivative able to grow on 0.1% decanoic acid) by a recycling selection procedure. Other E. coli strains tested showed behavior similar to that of strain K-12 154. The chilling of cells as a tool to improve the bactericidal action of fatty acids in foods is discussed. Fatty acids are used as antimicrobial food additives (1). The growth of gram-negative and-positive bacteria is inhibited by fatty acids (2, 3, 5, 8-11), the latter group being more sensitive to the fatty acid action (3, 10). The presence of a lipopolysaccharide layer, which typically surrounds the walls of gram-negative organisms, is suggested to be involved in the resistance to long-chain fatty acids (10). In Escherichia coli, the extent of growth inhibition by fatty acids is dependent on many variables, among which are the chain length of the added fatty acid and the culture medium in which the bacteria were grown (J. P. Fay and R. N. Farfas, J. Gen. Microbiol., in press). In this work we show that a cold pretreatment of cells greatly increases the bactericidal effect of some fatty acids on E. coli, and we suggest that this fact could be helpful in finding optimal conditions for the use of these compounds as preservatives for foods.

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“…), and were acquired by recombinants incorporating only the leading locus of the Hfr less often than by other classes. In E. coli Hfr crosses some colicine factors, including the coll factor we used (Monk & Clowes, 1964) and another one (Nagel de Zwaig et al, 1962), are more frequent in recombinants selected for a late, rather than an early marker-as though the probability of their transfer increased the longer the partners remained paired. In our experiments, however, the representation of coll and colE2 was higher in recombinants which had incorporated a long stretch of donor chromosome than in those with only an early, or with only a late marker, or with both early and late markers separated by recipient alleles.…”

Section: •T-ile-rha-mal-inl-(ara Azi Pro)-gal-(fia His)-adecmentioning

confidence: 99%

“…No such proof is available in respect of various other plasmids; the prophage form of phage P i , the colicine factors and the R (transmissible drug-resistance) factors. Alfoldi and his colleagues (Alfoldi etal., 1957(Alfoldi etal., , 1958 reported observations on Hfr crosses between colicinogenic and non-colicinogenic strains which led them to infer that an El colicine factor had a characteristic chromosomal location in Escherichia coli K12-but other workers have questioned their interpretation of the data and in similar crosses have found no evidence for chromosomal location of several different colicine factors in this species (Nagel de Zwaig, Anton & Puig, 1962;Clowes, 1963;Fredericq, 19636;Monk & Clowes, 1964;. We here report the behavior of three different colicine factors and an R factor during crosses of an Hfr derivative of Salmonella typhimurium strain LT2 carrying all four plasmids to an acceptor LT2 line carrying none of them.…”

Section: Introductionmentioning

confidence: 99%

Behavior of three colicine factors and an R (drug-resistance) factor in Hfr crosses inSalmonella typhimurium

Dubnau

Stocker

1967

Genet. Res.

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An LT2 Hfr strain,his metC gal, was crossed to a multiply marked LT2 F−line. Analysis of recombinant yields, segregation of unselected markers and interrupted matings indicated injection of the Hfr chromosome in the sequenceThe introduction into the Hfr of the colicine factorscolI, colE1andcolE2and the R factorR2had little or no effect on its fertility. All four factors were transmitted at low frequency to the F−population, and to recombinants at higher frequencies (colI5–30%,colE130–80%,colE25–30%,R20–9%). Transfer ofcolE1occurred before 20 min., that ofcolE2andcolIlater than 100 min. Segregation data did not reveal close linkage of any factor to any chromosomal locus, but recombinants with a long stretch of donor chromosome were more likely than others to have acquiredcolE2andcolI. Nearly all recombinants andF−cells which acquiredcolIorcolE2acquired both, andcolE1also. Most cells which acquiredR2acquired one or more colicine factors. These plasmid associations can be formally represented by transfer of plasmids, independently of the chromosome, in the sequencecolE1—(colI, colE2)—R2. Phage P22 grown on the Hfr carrying the four plasmids transduced thetet-rtrait ofR2at very low frequency, and thesul-r str-rcharacters, together, at low frequency. Some of each sort of drug-resistance transductant, but no transductants in respect of chromosomal characters, acquiredcolEl or colE2by co-transduction.

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The Genetic Control Colicinogenic Factors E2 I and V

Cited by 32 publications

References 3 publications

Cellular damage associated with multiple mating inE. coli

Cellular damage associated with multiple mating inE. coli

Chilling cells enhances the bactericidal action of fatty acids on Escherichia coli

Behavior of three colicine factors and an R (drug-resistance) factor in Hfr crosses inSalmonella typhimurium

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