منابع مشابه
Streptomyces thermoautotrophicus does not fix nitrogen.
Streptomyces thermoautotrophicus UBT1 has been described as a moderately thermophilic chemolithoautotroph with a novel nitrogenase enzyme that is oxygen-insensitive. We have cultured the UBT1 strain, and have isolated two new strains (H1 and P1-2) of very similar phenotypic and genetic characters. These strains show minimal growth on ammonium-free media, and fail to incorporate isotopically lab...
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A new study asserts that a late evolutionary leap in cyanobacterial nitrogen fixation terminated a long history of nitrogen-limited primary production in the ocean--and contributed to a dramatic increase in biospheric oxygen coincident with the rise of animals.
متن کاملSanctions and mutualism stability: why do rhizobia fix nitrogen?
Why do rhizobia expend resources on fixing N(2) for the benefit of their host plant, when they could use those resources for their own reproduction? We present a series of theoretical models which counter the hypotheses that N(2) fixation is favoured because it (i) increases the exudation of useful resources to related rhizobia in the nearby soil, or (ii) increases plant growth and therefore th...
متن کاملMutants of azotobacter that do not fix nitrogen.
Stable strains of mutants of Azotobacter that do not fix nitrogen are difficult to obtain by traditional procedures (Karlsson and Barker, 1948; Lindstrom, 1948). Stumbo and Gainey (1938) demonstrated that culturing Azotobacter on a high nitrate medium resulted in strains that failed to fix nitrogen even after continued transfer in the absence of fixed nitrogen. However, since these strains were...
متن کاملHow many metals does it take to fix N2? A mechanistic overview of biological nitrogen fixation.
During the process of biological nitrogen fixation, the enzyme nitrogenase catalyzes the ATP-dependent reduction of dinitrogen to ammonia. Nitrogenase consists of two component metalloproteins, the iron (Fe) protein and the molybdenum-iron (MoFe) protein; the Fe protein mediates the coupling of ATP hydrolysis to interprotein electron transfer, whereas the active site of the MoFe protein contain...
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ژورنال
عنوان ژورنال: Nature
سال: 2005
ISSN: 0028-0836,1476-4687
DOI: 10.1038/436786a