Mo-independent nitrogenase 3 is advantageous for diazotrophic growth of Azotobacter vinelandii on solid medium containing molybdenum

Maynard, R H; Premakumar, R.; Bishop, Paul E.

doi:10.1128/jb.176.17.5583-5586.1994

Cited by 25 publications

(14 citation statements)

References 21 publications

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“…This could lead to a competitive advantage by generating ecological niches that exclude diazotrophs lacking Mo-independent nitrogenases. Consistent with this hypothesis are the results of competition experiments where wild-type A. vinelandii had an advantage over a mutant lacking Mo-independent nitrogenase 3 on Mo-sufficient solid media but not in liquid media (36). If this hypothesis holds for other diazotrophs with Mo-independent nitrogenases, then it is reasonable to expect to find these diazotrophs in macroenvironments that have sufficient Mo concentrations for Mo-dependent nitrogen fixation.…”

Section: Resultssupporting

confidence: 71%

“…The ability of diazotrophs with Mo-independent nitrogenases to grow in a wide variety of environments, including those known to have sufficient Mo concentrations for Modependent nitrogen fixation, might be determined by other environmental factors (e.g., temperature) in addition to the concentration of Mo in the macroenvironment (4,36). As such, we were able to isolate strains with Mo-independent nitrogenases using enrichment media containing 1 M Na 2 MoO 4 (strains MU1 and MU2).…”

Section: Resultsmentioning

confidence: 87%

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Characterization of Diazotrophs Containing Mo-Independent Nitrogenases, Isolated from Diverse Natural Environments

Betancourt¹,

Loveless

Brown³

et al. 2008

Appl Environ Microbiol

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Molybdenum-independent nitrogenases were first described in the nitrogen-fixing bacterium Azotobacter vinelandii and have since been described in other diazotrophic bacteria. Previously, we reported the isolation of seven diazotrophs with Mo-independent nitrogenases from aquatic environments. In the present study, we extend these results to include diazotrophs isolated from wood chip mulch, soil, "paraffin dirt," and sediments from mangrove swamps. Mo-deficient, N-free media under both aerobic and anaerobic conditions were used for the isolations. A total of 26 isolates were genetically and physiologically characterized. Their phylogenetic placement was determined using 16S rRNA gene sequence analysis. Most of the isolates are members of the gamma subdivision of the class Proteobacteria and appear to be specifically related to fluorescent pseudomonads and azotobacteria. Two other isolates, AN1 and LPF4, are closely related to Enterobacter spp. and Paenibacillus spp., respectively. PCR and/or Southern hybridization were used to detect the presence of nitrogenase genes in the isolates. PCR amplification of vnfG and anfG was used to detect the genetic potential for the expression of the vanadium-containing nitrogenase and the iron-only nitrogenase in the isolates. This study demonstrates that diazotrophs with Mo-independent nitrogenases can be readily isolated from diverse natural environments.

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 87%

Characterization of Diazotrophs Containing Mo-Independent Nitrogenases, Isolated from Diverse Natural Environments

Betancourt¹,

Loveless

Brown³

et al. 2008

Appl Environ Microbiol

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“…Evidence to support this view is that Fe-nitrogenase is found to be advantageous for diazotrophic growth of A. vinelandii on solid Burk's medium when Mo has been exhausted (Maynard et al 1994 …”

Section: Other Possibly Alternative Nitrogenasesmentioning

confidence: 74%

Diversity of Nitrogenase Systems in Diazotrophs

Zhao

Bian

Zhou

et al. 2006

JIPB

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Nitrogenase is a metalloprotein complex that catalyses the reaction of biological nitrogen fixation. At least three genetically distinct nitrogenase systems have been confirmed in diazotrophs, namely Nif, Vnf, and Anf, in which the active-site central metals are Mo, V, and Fe, respectively. The present review summarizes progress on the genetic, structural, and functional investigations into the three nitrogenases and discusses the possibility of the existence of other novel nitrogenases. Key words: diazotroph; FeMo-cofactor and cofactors substituted for Mo; nitrogenase system; P-cluster. Zhao Y, Bian SM, Zhou HN, Huang JF (2006). Diversity of nitrogenase systems in diazotrophs. J Integrat Plant Biol 48(7), 745−755.www.blackwell-synergy.com; www.jipb.net . Review .Biological nitrogen fixation is an essential step in the global nitrogen cycle and this reaction is necessary to sustain life on earth (Seefeldt et al. 2004). Nitrogen fixation is mediated by the enzyme system nitrogenase, which, although found in a relatively few groups of prokaryotes, is responsible for the cycling of some 10 8 tons of N per year (Eady et al. 1996(Eady et al. , 2003. In general, the nitrogenase enzyme is composed of two oxygenlabile and separable metalloproteins, dinitrogenase (component I) and dinitrogenase reductase (component II). Component I contains the active site for N 2 reduction, with a molecular weight of approximately 240 kDa and is composed of two heterodimers. Component II is a 60-70 kDa homodimer coupling ATP hydrolysis to interprotein electron transfer (Zehr et al. 2003). At least three genetically distinct nitrogenase systems have been identified until now: Nif, Vnf, and Anf. Apart from the three O 2 -sensitive nitrogenases, a third alternative, but completely nif/ vnf/anf-independent and O 2 -insensitive nitrogenase system, has b e e n r e p o r t e d r e c e n t l y t o o c c u r i n S t r e p t o m y c e s thermoautotrophicus (Ribbe et al. 1997). Many studies have been conducted focusing on the structure and mechanism of nitrogenase systems. In recent years, considerable progress has been made towards establishing the mechanism of the action of nitrogenase complex, reflecting the contribution of a combination of structural, biochemical, spectroscopic, synthetic, and theoretical approaches to a challenging problem, with implications for a range of biochemical and chemical systems (Rees and Howard 2000).In the present review, we focus on the genetics, molecular biology and the structure and function of alternative (Moindependent) nitrogenases. The possibility of the existence of some novel nitrogenases is also discussed.

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“…First, diazotrophically growing bacteria take up Mo from their immediate environment, which leads to a self-inflicted Mo limitation in the surrounding medium that subsequently results in the expression of Fe-nitrogenase in the cells (Maynard et al, 1994).…”

Section: Implications For the Role Of The Heterometalmentioning

confidence: 99%

Iron-Only Nitrogenase: Exceptional Catalytic, Structural and Spectroscopic Features

Schneider

Müller

2004

Catalysts for Nitrogen Fixation

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Mo-independent nitrogenase 3 is advantageous for diazotrophic growth of Azotobacter vinelandii on solid medium containing molybdenum

Cited by 25 publications

References 21 publications

Characterization of Diazotrophs Containing Mo-Independent Nitrogenases, Isolated from Diverse Natural Environments

Characterization of Diazotrophs Containing Mo-Independent Nitrogenases, Isolated from Diverse Natural Environments

Diversity of Nitrogenase Systems in Diazotrophs

Iron-Only Nitrogenase: Exceptional Catalytic, Structural and Spectroscopic Features

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