Nitrogen fixation genes

Fig. 12. The nitrogen fixation genes of Azotobacter vinelandii. This orgEinism has three nitrogenase systems, viz nif, vnf, and anf, which it uses for fixing N2 under different environmental conditions. The boxes with slanted hatching indicate the structural genes of the three systems, those colored dark gray are required for eiU three systems, and those with vertical hatching are required for both the vnf and anf systems.

C. Quinto, H de la Vega, M. Elores, L. Eernandez, T. Ballado, G. Soberon, and R. Palacios, Reiteration of nitrogen fixation gene. sequences in Rhizobium phaseoli. Nature 299 724-726 (1982). 

Golden, J. W., Robinson, S. J. and Haselkorn, R. (1985) Rearrangement of nitrogen fixation genes during heterocyst differentiation in the cyanobacterium Anabaena. Nature, 314, 419-23. 

Szeto, W.W. Nixon, B.T. Ronson, C.W. Ausubel, EM. Identification and characterization of the Rhizobium meliloti ntrC gene R. meliloti has separate regulatory pathways for activation of nitrogen fixation genes in free-living and symbiotic cells. J. BacterioL, 169, 1423-1432 (1987)... 

Birkenhead, K., Yang, Y.-P., Noonan, B., Manian S.S. O Gara, F. (1988). Characterization of Rhizobium meliloti DCT genes and relationship between utilization of dicarboxylic acids and expression of nitrogen fixation genes. In Molecular Genetics of Plant-Microbe Interactions, ed. R. Palacios D.P.S. Verma, pp. 137-8. St Paul, MO APS Press. 

NADH, reduced nicotinamide-adenine dinueleotide Q, coenzyme Q FNR, fumarate nitrate reduction SoxR, superoxide activated regulatory protein IRP, iron regulatory protein NIFU, nitrogen fixation gene U product. 

Zehr, J. P., Mellon, M., Braun, S., Litaker, W., Steppe, T., and Paerl, H. W. (1995). Diversity of heterotrophic nitrogen fixation genes in a marine cyanobacteria mat. Appl. Environ. Microbiol. 61, 2527-2532. 

Advances are also being made in the more complex area of the molecular biology of symbiotic nitrogen fixation. Genes in Rhizobia involved in recognition, infection and nodulation have been identified, while some progress has been made with the plant genes and proteins involved in the development of root nodules. 

Meeks J.C., Campbell E.L. and Bisen P.S. (1994). Elements interrupting nitrogen fixation genes in cyanobacteria presence and absence of a nifD element in clones of Nostoc sp. strain Mac. Microbiol. 140, 3225-3232. 

Misra, H.S. and Tuli, R. (2000) Differential expression of photosynthesis and nitrogen fixation genes in the cyanobacterium Plectonema horyanum. Plant Physiol, 122 (3), 731-736. 

Temme, K., Zhao, D., and Voigt, C.A. (2012) Refactoring the nitrogen fixation gene cluster from Klebsiella oxytoca. Proc. Natl. Acad. Sci. U.S.A., 109 (18), 7085-7090. 

Hill S, Austin S, Eydmann T, Jones T, Dixon R. Azotobacter vinelandii NilL is a flavoprotein that modulates transcriptional activation of nitrogen-fixation genes via a redox-sensitive switch. Proc Natl Acad Sci USA 1996 93 2143-2148. 

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