Conjugation and Genetic Recombination in Escherichia coli K-12

Wollman, Elie L.; Jacob, François; Hayes, William

doi:10.1101/sqb.1956.021.01.012

Cited by 201 publications

(83 citation statements)

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“…One of the features of Hfr transfer in E. coli is that a gradient of transfer is seen, with more frequent transfer of markers proximal to oriT than of those more distal (Wollman et al, 1956). As M. smegmatis lacks many well-defined genetic markers, we are unable to carry out such an elaborate experiment.…”

Section: Chromosomal Transfer Is Extensivementioning

confidence: 99%

Conjugal transfer of chromosomal DNA in Mycobacterium smegmatis

Parsons

Jankowski

Derbyshire

1998

Molecular Microbiology

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SummaryThe genus Mycobacterium includes the major human pathogens Mycobacterium tuberculosis and Mycobacterium leprae. The development of rational drug treatments for the diseases caused by these and other mycobacteria requires the establishment of basic molecular techniques to determine the genetic basis of pathogenesis and drug resistance. To date, the ability to manipulate and move DNA between mycobacterial strains has relied on the processes of transformation and transduction. Here, we describe a naturally occurring conjugation system present in Mycobacterium smegmatis, which we anticipate will further facilitate the ability to manipulate the mycobacterial genome. Our data rule out transduction and transformation as possible mechanisms of gene transfer in this system and are most consistent with conjugal transfer. We show that recombinants are not the result of cell fusion and that transfer occurs from a distinct donor to a recipient. One of the donor strains is mc 2 155, a highly transformable derivative that is considered the prototype laboratory strain for mycobacterial genetics; the demonstration that it is conjugative should increase its genetic manipulability dramatically. During conjugation, extensive regions of chromosomal DNA are transferred into the recipient and then integrated into the recipient chromosome by multiple recombination events. We propose that DNA transfer is occurring by a mechanism similar to Hfr conjugation in Escherichia coli.

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Section: Chromosomal Transfer Is Extensivementioning

confidence: 99%

Conjugal transfer of chromosomal DNA in Mycobacterium smegmatis

Parsons

Jankowski

Derbyshire

1998

Molecular Microbiology

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“…The fact that energy is also required for chromosome transfer raises the question whether the irreversible link uniting the cells is really the chromosome itself. Electron microphotographs show the presence of a bridge of material between conjugating cells (Wollman, Jacob & Hayes, 1956). This bridge is clearly not the chromosome, as the absence of effect of DNA-ase on recombination had already suggested (Lederberg, 1947 ;Hayes, 1957).…”

Section: Discussionmentioning

confidence: 99%

The Nature of the Endergonic Processes in Conjugation in Escherichia coli K-12

Fisher

1957

Journal of General Microbiology

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SUMMARY:The energy required during zygote formation was found to be needed solely by the donor parent. The free energy is utilized by the donor cell in the establishment of effective contacts and subsequently in the transfer of the genetic material to the F -cell. Energy is not required to hold the cells in contact throughout the mating process. The effect of pH value on the recombination rate is described.Zygote formation in Escherichia coli K-12 is an endergonic process which is probably not dependent on protein or nucleic acid synthesis (Fisher, 1957). This paper describes an analysis of zygote formation in order to establish more precisely the nature of the endergonic stages. METHODSThe materials and bacterial strains used have been described previously (Fisher, 1957). In the present experiments, however, beef-digest broth was replaced by casein hydrolysate yeast extract broth (CHYE) (Difco ' Casamino acids', Technical, 2 yo (w/v) +Difco dehydrated yeast extract, 0.5 yo (w/v); pH value adjusted to 7-4). Escherichia coli K-12, strains 58-161 Hfr (Hayes, 1953) and W-1 F- (Lederberg & Lederberg, 1952) were used exclusively.The methods used to grow the parent cultures and to detect the formation of zygotes were as described by Fisher (1957). Other experimental procedures varied with the demands of particular experiments and will be described in their proper place in the text. (Fisher, 1957) that free energy is required for zygote formation. An analysis of this energy requirement must first resolve whether the energy is required by one or both parents and, secondly, the particular stage or stages of conjugation which are endergonic. RESULTS It was shown The energy requirements of each parent during conjugationThough optimal zygote formation occurs in buffer +glucose + aspartate, zygotes are still formed at a low rate in unsupplemented buffer. It was thought that the low rate which occurred in buffer might be due to endogenous carbohydrate reserves of the bacteria. The effect of starvation on washed parent cells was therefore investigated. The cells were differentially depleted of their carbohydrate or nitrogenous reserves by aeration at 37' in buffer supplemented

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“…The behaviour of col+ str-r colonies is in striking contrast to that of chromosomal recombinants, such as thr+ leu+ str-r. When chromosomal markers are transferred they must integrate in the genome of the recipient cell in order to reduplicate; the probability of integration being less than *, the frequency of transmission to recombinants becomes much less than the frequency of transfer to zygotes (Wollman, Jacob & Hayes, 1956). Furthermore, chromosomal recombinants begin to multiply only after integration has been accomplished (Fig.…”

Section: Discussionmentioning

confidence: 99%

The Genetic Control Colicinogenic Factors E2 I and V

Zwaig¹,

Antón

Puig³

1962

Journal of General Microbiology

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SUMMARYThe state of colicinogenic factors E,, I and V (col E,, col I and col V ) in Escherichia coli K12 was studied. The analysis of the results of conjugation experiments involving different Hfr or F+ and F-strains shows that: (1) The frequency of transfer of these colicinogenic factors differs markedly: col V is transferred with maximum efficiency, col E, and col I , on the contrary, only at low frequency. The non-colicinogenic character of the donor parent is never transmitted to recombinants. ( 5 ) Zygotes that have received col V , transmit it to all daughter cells. All these results lead to the conclusion that colicinogenic factors E,, I and V are in an extrachromosomal state in F+ and Hfr bacteria. The same conclusion would apply to their state in F-bacteria, since the results with colicinogenic factor V seem to indicate that this factor replicates in this type of bacteria autonomously and at a faster rate than the chromosome.

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Conjugation and Genetic Recombination in Escherichia coli K-12

Cited by 201 publications

References 0 publications

Conjugal transfer of chromosomal DNA in Mycobacterium smegmatis

Conjugal transfer of chromosomal DNA in Mycobacterium smegmatis

The Nature of the Endergonic Processes in Conjugation in Escherichia coli K-12

The Genetic Control Colicinogenic Factors E2 I and V

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