نتایج جستجو برای: n2 fixation
تعداد نتایج: 70968 فیلتر نتایج به سال:
Nitrogen fixation is a tightly regulated trait. Switching from N2 fixation-repressing conditions to the N2-fixing state is carefully controlled in diazotrophic bacteria mainly because of the high energy demand that it imposes. By using quantitative real-time PCR and quantitative immunoblotting, we show here how nitrogen fixation (nif) gene expression develops in Azotobacter vinelandii upon dere...
Dinitrogen fixation by Nostoc azollae residing in specialized leaf pockets supports prolific growth of the floating fern Azolla filiculoides. To evaluate contributions by further microorganisms, the A. filiculoides microbiome and nitrogen metabolism in bacteria persistently associated with Azolla ferns were characterized. A metagenomic approach was taken complemented by detection of N2 O releas...
A PREVIOuS report [Wyss & Wilson, 1941] demonstrated that B2 inhibits fixation of N2 by Azotobacter. Because of the apparent uniqueness of this type of inhibition, such a demonstration furnishes strong evidence that in the symbiotic and free-living N2 fixation processes the mechanism of fixation is very similar if not identical. Further studies described in this paper provide additional support...
Recent observations of N2 fixation rates (NFR) and the presence of nitrogenase (nifH) genes from heterotrophic N2-fixing (diazotrophic) prokaryotes in unusual habitats challenge the paradigm that pelagic marine N2 fixation is constrained to cyanobacteria in warm, oligotrophic, surface waters. Here, we compare NFR and diazotrophic diversity (assessed via high-throughput nifH sequencing) from a r...
In temperate Atlantic waters (18.8 to 20.1°C), biological nitrogen fixation has been demonstrated by 2 independent measurements: N-N2 incorporation and nifH identification in the DNA and expressed messenger RNA (mRNA). At 2 stations in the western English Channel, bulk waters were incubated with N-N2. At the high levels of particulate nitrogen (≤11.5 μmol N l–1), absolute fixation rates of 18.9...
Trichodesmium, a nonheterocystous cyanobacterium widely abundant in the surface water of the tropical and subtropical ocean, fixes dinitrogen under high light conditions while concurrently undergoing photosynthesis. The new production considerably influences the cycling of nitrogen and carbon in the ocean. Here, we investigated how light intensity and nickel (Ni) availability interplay to contr...
The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N2-fixation that are required to do so. We present results from a new Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N2-fixation with l...
EDITORIAL article Front. Mar. Sci., 04 March 2021 | https://doi.org/10.3389/fmars.2021.664195
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