Competence for Genetic Transformation in Acinetobacter Calcoaceticus Ncib8250

Ahlquist, E. F.; Fewson, Charles A.; Ritchie, Donald A.; Podmore, J.; Rowell, V.

doi:10.1111/j.1574-6941.1980.tb01586.x

Cited by 19 publications

(10 citation statements)

References 14 publications

(4 reference statements)

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“…Acinetobacter calcoaceticus is a gram-negative and metabolically versatile organism (Juni 1978). Some A. calcoaceticus strains are naturally transformable (Juni and Janik 1969;Ahlquist et al 1980). Of these, strain BD413 is suitable for use as a model system to study natural transformation in gramnegative bacteria because high transformation frequencies can be obtained and the organism is easily grown into the competent state (Juni and Janik 1969;Juni 1972;Sawula and Crawford 1972;Palmen et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Physiological regulation of competence induction for natural transformation in Acinetobacter calcoaceticus

1994

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Acinetobacter calcoaceticus induced competence for natural transformation maximally after dilution of a stationary culture into fresh medium. Competence was gradually lost during prolonged exponential growth and after entrance into the stationary state. Growth cessation and nutrient upshift were involved in the induction of competence. The level of competence of a chemostat culture of A. calcoaceticus was dependent on the nature of the growth limitation. Under potassium limitation a transformation frequency of + 1 x 10 .4 was obtained. This frequency was independent of the specific growth rate. In phosphate-, nitrogen-, and carbon-limited chemostat cultures, in contrast, the transformation frequency depended on the specific growth rate; the transformation frequency equalled _+ 10.4 at dilution rates close to g,~a• of 0.6h -1 and decreased to _+ 10 -7 at a dilution rate of 0.1 h-L We conclude that (1) DNA uptake for natural transformation in A.calcoaceticus does not serve a nutrient function and (2) competence induction is regulated via a promoter(s) that resembles the fis promoter from Escherichia coli.

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Section: Introductionmentioning

confidence: 99%

Physiological regulation of competence induction for natural transformation in Acinetobacter calcoaceticus

1994

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“…Transformation on filters of mutants of wild-type strain NCIB8250, using DNA (58 /~g/filter) from NCIB8250 itself, also failed to yield the high frequencies of recombinants found in filter matings. Unlike transformation [4], addition of DNase before incubation of the mating mixture failed to cause any decrease in the frequency of appearance of recombinants. Furthermore, incubation of C1408 with a filtrate obtained from a culture of strain C1632 did not give a significant number of recombinants, suggesting that transduction was not likely to be responsible for the gene transfer observed in the filter matings.…”

Section: Mechanism Of the Genetic Transfermentioning

confidence: 80%

“…In contrast, transformation does not seem to occur in most acinetobacters [2] and could not be demonstrated in strain EBF65/65 (Lau, K. and Vivian, A., unpublished results) although RP4-mediated conjugation and chromosome mobilization has been observed in this strain [3]. Strain NCIB8250 which is apparently quite closely related to EBF65/65, is transformable but frequencies are low and competence is achieved only under certain growth conditions [4].…”

Section: Introductionmentioning

confidence: 95%

Gene transfer inAcinetobacter calcoaceticusNCIB8250

Vakeria

Fewson

Vivian

1985

FEMS Microbiology Letters

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Filter matings of mutant strains of Acinetobacter calcoaceticus NCIB8250 showed that catabolic and auxotrophic markers were transferred in the absence of a conjugative plasmid. There were no specific ‘donor’ or ‘recipient’ strains. Deoxyribonuclease had no effect on the mating system. Some crosses appeared to be highly polarized towards certain parental strains whilst others showed a two‐way transfer of genetic markers. There was a high frequency of transfer of the ability to utilize L(+)‐mandelate from a mutant of A. calcoaceticus NCIB8250 to certain strains of a second wild‐type, EBF65/65, but there was no evidence that the recombinants had acquired another plasmid. This process, whose mechanism is not clear, has some potential in the construction of novel strains but is not likely to be generally useful for mapping purposes and may even prove to be a hazard in the interpretation of results from other genetic techniques.

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“…This work was in contrast with earlier work with A . calcoaceticus strains BD413 and NCIB 8250, in which competence was found only during the mid-exponential growth phase (Ahlquist et al, 1980;Cruze et al, 1979). Thus, the HFT Vibrio WJT-1C seems to be unique with respect to competence development and maintenance.…”

Section: Discussionmentioning

confidence: 91%

Factors affecting competence in a high frequency of transformation marine Vibrio

Frischer

Thurmond

Paul

1993

Journal of General Microbiology

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Natural plasmid transformation may be a mechanism for the horizontal transfer of non-conjugative plasmids in the marine environment, yet there are few marine model systems available for the study of this process. Using multimers of IncQ/P4 plasmids and a filter transformation assay, we have measured the effects of nutrients, salinity, temperature, as well as the development and maintenance of competence for genetic transformation in the high frequency of transformation (HFT) marine Vibrio strain WJT-1C. Transformation frequency was proportional to the amount of DNA used from 0.1 to 1.0 pg DNA and was saturated at concentrations greater than 1-0 pg. Competence began in the early-exponential phase and reached a maximum at the onset of stationary phase. Once attained, competence was maintained in both spent and nutrient-free media for at least 10 d. Thus, the establishment and maintenance of competence was unique compared to previously described transformation systems. Temperatures ranging from 4 to 33 "C had no significant effect on the maximal transformation frequency of WJT-lC, but at 37 "C the transformation frequency was reduced. However, temperature did affect the rate of the transformation process. Salinities in the range 12 to 50%, had no significant effect on the transformation frequency but transformation frequencies were lower at 6%, and 63%,. Cells were transformed equally well in nutrient-free media or rich media. The ability of this marine HF'T Vibrio strain to develop competence under a wide spectrum of conditions and to maintain the competent state indicates that natural plasmid transformation could occur in conditions found in tropical and subtropical estuaries.

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Competence for Genetic Transformation in Acinetobacter Calcoaceticus Ncib8250

Cited by 19 publications

References 14 publications

Physiological regulation of competence induction for natural transformation in Acinetobacter calcoaceticus

Physiological regulation of competence induction for natural transformation in Acinetobacter calcoaceticus

Gene transfer inAcinetobacter calcoaceticusNCIB8250

Factors affecting competence in a high frequency of transformation marine Vibrio

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