Mutants That Produce Nitrogenase in the Presence of Ammonia

Gordon, Joyce K.; Brill, Winston J.

doi:10.1073/pnas.69.12.3501

Cited by 57 publications

(18 citation statements)

References 20 publications

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“…Duplicated segments, which are cis and tandem to the original loci, are known to be unstable (Novick, 1969), in contrast to duplicated integrations which are stabilized by genetic inversion (Adelberg & Bergquist, 1972 (Shah, Davis & Brill, 1972). By selecting re\ ertants of an Azotobacter mutant unable to synthesize any component of nitrogenase, Gordon & Brill (1972) isolated constitutive mutants, which produced nitrogenase in the presence of NH,'. We have observed that the Escherichia coli Nif-hybrid, C -~7 , produces a niirogenase with the same physiological properties as that of the Klebsiella donor strain.…”

Section: Nitrogen Jixatioti Gmes Ill E Coli 237mentioning

confidence: 99%

Chromosomal Integration of Klebsiella Nitrogen Fixation Genes in Escherichia coli

Cannon

Dixon

Postgate

et al. 1974

Journal of General Microbiology

126

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S U M M A R YEscherichia coli, C-M7, a His+Nif+ hybrid obtained by intergeneric mating with a Klebsiella pneumoniae donor strain, also inherited the unselected markers gnd and rfb. The R factor, R144drd3, which had been used to confer fertility on the donor, was present, detectable as covalently closed circular DNA of molecular weight 69 x lo6 daltons. No other species of supercoiled DNA were isolated and the elimination of R144drd3 did not result in the loss of Klebsiella genes. Segregation analysis of donor markers indicated that the Klebsiella DNA was integrated at the his region of the E. coli chromosome in the probable order his-gnd-nif-rfb. Strain C-M7 produced a nitrogenase physiologically identical to that of K. pneumoniae, but synthesized a heteromeric species of gluconate-6-phosphate dehydrogenase.

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Section: Nitrogen Jixatioti Gmes Ill E Coli 237mentioning

confidence: 99%

Chromosomal Integration of Klebsiella Nitrogen Fixation Genes in Escherichia coli

Cannon

Dixon

Postgate

et al. 1974

Journal of General Microbiology

126

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“…Regulatory mutants of nif in A. vinelandii include those which lack the ability to synthesise both MoFe and Fe proteins under derepressing conditions (Shah et al 1973); those which synthesise nitrogenase constitutively in NH4+ (Gordon and Brill 1972); and an interesting mutant (UW38), having no parallel in K. pneumoniae, which fails to make MoFe protein but overproduces Fe protein .…”

Section: Regulation Of Nif Genes In Other Speciesmentioning

confidence: 99%

Progress in comparative genetics of nitrogen fixation

Robson¹,

Kennedy²,

Postgate³

1983

Can. J. Microbiol.

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“…Studies with mutants unable to assimilate added NH: into glutamine, or inhibition of this process by methionine sulphoximine (MSX), have shown that repression of nif'by NH,+ requires its assimilation into glutamine (Gordon & Brill, 1972).…”

Section: Introductionmentioning

confidence: 99%

Nitrogenase Synthesis in Klebsiella pneumoniae: Enhanced nif Expression without Accumulation of Guanosine 5'-Diphosphate 3'-Diphosphate

Nair

Eady

1984

Microbiology

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Derepression of nitrogen fixation (nif) genes in Klebsiella pneumoniae following transfer from NH+4-sufficiency to N-free medium was preceded by rapid expansion of the guanosine 5'-diphosphate 3'-diphosphate (ppGpp) pool. When derepressed in N-free medium supplemented with glutamine (600 micrograms ml-1), expression from the nifH and nifL promoters, determined as beta-galactosidase activity in nif::lac merodiploid strains, was stimulated 7-fold and nitrogenase activity 26-fold; ppGpp did not accumulate, remaining at the levels found in NH+4-repressed populations. The relaxed mutant K. pneumoniae relA40, which accumulates only very low levels of ppGpp, showed partial derepression of nitrogenase activity in the presence of glutamine, thus ppGpp is unlikely to be an effector of nif expression. ATP and GTP levels were elevated under conditions where nif expression was enhanced, consistent with previous data suggesting that maintenance of ATP levels is a prerequisite for the expression of nif genes in K. pneumoniae.

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Mutants That Produce Nitrogenase in the Presence of Ammonia

Abstract: Rhizobium-legume symbionts and all Nrfixing bacteria and Nrfixing blue-green algae that have been examined exhibit a striking level of repression of nitrogenase synthesis when excess NH4+ is added to the growth medium (for example, refs.

Cited by 57 publications

References 20 publications

Chromosomal Integration of Klebsiella Nitrogen Fixation Genes in Escherichia coli

Chromosomal Integration of Klebsiella Nitrogen Fixation Genes in Escherichia coli

Progress in comparative genetics of nitrogen fixation

Nitrogenase Synthesis in Klebsiella pneumoniae: Enhanced nif Expression without Accumulation of Guanosine 5'-Diphosphate 3'-Diphosphate

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