An Infective Factor Controlling Sex Compatibility in Bacterium coli

Cavalli, L. L.; Lederberg, Joshua; Lederberg, Esther

doi:10.1099/00221287-8-1-89

Cited by 102 publications

(47 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These data are insufficient to determine the relative order of xylose and mannitol. This is in partial agreement with the order given by Clowes & Rowley (1954) and in agreement with Cavalli-Sforza & Jinks (1956).…”

Section: The Efect Of F On the Transfer Of Unselected Marlcerssupporting

confidence: 80%

The Presence of the Transmissible Agent F in Non-Recombining Strains of Escherichia coli

Furness

Rowley

1957

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARY: A proportion of wild-type strains of Escherichia co2i unable to recombine with E. coli K12 F-mutants can 'infect' them with the sex-differentiating character known as F. Of these strains, not all infect the same E . coli K12 Fmutants and the ease of transfer of F varies among them, suggesting that there are different F agents. T@s is supported by the finding that there are great variations in the transfer of unselected markers in crosses in which the only known difference is the origin of the F factor possessed by the F + parent.Colicinogenicity and F are frequently associated and all of nine strains producing colicin I possess F, but they are not identical, since the two properties have been separated by treatment with cobalt chloride.

show abstract

Section: The Efect Of F On the Transfer Of Unselected Marlcerssupporting

confidence: 80%

The Presence of the Transmissible Agent F in Non-Recombining Strains of Escherichia coli

Furness

Rowley

1957

Journal of General Microbiology

View full text Add to dashboard Cite

show abstract

“…These h+ mutants were probably not due to a mixture of suppressor-and true back-mutations (Witkin & Kennedy, 1951) because Lieb (1951) showed, by studying nineteen randomly isolated h+ reversions of independent origin, that their rates of mutation to the h-state were the same and averaged 1.2 x lO-e/bacterium/generation. Although mutability is an extremely sensitive test, a critical decision cannot be made since, despite repeated attempts to introduce F+ factor (Cavalli, Lederberg & Lederberg, 1953) into strain 15, sexual crosses have been unsuccessful.…”

Section: Methodsmentioning

confidence: 99%

Nuclear Segregation and the Growth of Clones of Spontaneous Mutants of Bacteria

Ryan

Wainwright

1954

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARY: An investigation of the rate of increase of spontaneous mutants and the subsequent increase in mutant proportion in a bacterial culture revealed discrepancies between the observed results and those expected on the assumption that mutant and parent grew with equal rates. These discrepancies could not be accounted for in terms of a selective difference between established mutants and their parents since, when the two were mixed together in reconstruction experiments, they fared equally well for hundreds of generations. Rather the discrepancies indicated a difference between parents and new mutants. The data were consistent with the hypothesis that the mutation occurred independently among one of four mutable units (nuclei) and that the mutant nucleus was 'dominant' over its sister non-mutant nuclei in the heterocaryon so formed. As a consequence, a delay of two generations ensued before the mutant unit segregated into the homocaryotic ancestor of a mutant clone. This process delayed the onset of an increase in mutant numbers after mutation. The accurate prediction of the pseudo-equilibrium level of mutants, based on verifiable assumptions of periodic selection, mutation and segregation lag, is added evidence for the occurrence of a two-generation delay before the increase of the mutant clone. This phenomenon, called segregation lag, is a source of error in the calculation of mutation rate by methods involving the numbers of mutants found in bacterial cultures. Furthermore, because bacteria may be multinucleate, the rate of mutation/bacterium/generation is not the same as the rate of mutation/mutable unit (nucleus)/generation.That a growing bacterium may contain more than one body consisting of deoxyribonucleic acid is well known. Witkin (1951) was the first, however, to offer direct evidence indicating that these bodies contain genetic material and are the counterparts of nuclei. Her evidence was threefold. First, the ratio of wholly mutant colonies to those containing mutant sectors was proportional to the ratio of uninucleate bacteria in the irradiated culture which gave rise to the colonies. This finding is consistent with the hypothesis that sectored colonies originate through segregation of the nuclear bodies during growth. Secondly, there was a proportionality between the frequency of induced mutants, whole and sectored, and the frequency of bacteria with more than one nuclear body. Finally, there was some correlation between the types of sectored colonies and the most frequent number of nuclear bodies/multinucleate cell; cultures with mostly binucleate bacteria gave rise predominantly to half sectors while cultures consisting for the most part of cells with four nuclei gave rise predominantly to quarter sectors. A more extensive correlation was not attempted because of the difficulty in determining nuclear numbers.This difficulty is even greater with bacteria that have been grown 0.n chemically defined media. Yet it is sometimes necessary to know the average number

show abstract

“…It was later shown that the donor character, called F (for fertility), could be transferred to recipient cells independently of the usual genetic markers and with an efficiency of the order of 100% (Lederberg, Cavalli & Lederberg, 1952;Cavalli, Lederberg & Lederberg, 1953 ;Hayes, 1953a). Crosses between recipient (F -) strains were sterile; crosses between donor (F + ) and recipient strains showed maximum fertility.…”

mentioning

confidence: 99%

“…Two donor mutants were independently isolated from strain 58-161 F + which were about 1000 times more productive in crosses with the same F-strain (Cavalli, 1950;Hayes, 19533). These mutants, which were unable to convert F -cells to the F + state, were called Hfr (high frequency of recombination).…”

mentioning

confidence: 99%

The Role of the Krebs Cycle in Conjugation in Escherichia coli K-12

Fisher

1957

Journal of General Microbiology

View full text Add to dashboard Cite

An Infective Factor Controlling Sex Compatibility in Bacterium coli

Cited by 102 publications

References 23 publications

The Presence of the Transmissible Agent F in Non-Recombining Strains of Escherichia coli

The Presence of the Transmissible Agent F in Non-Recombining Strains of Escherichia coli

Nuclear Segregation and the Growth of Clones of Spontaneous Mutants of Bacteria

The Role of the Krebs Cycle in Conjugation in Escherichia coli K-12

Contact Info

Product

Resources

About