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Content with the tag: “nitrogen cycle”
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An Alternative Path for the Evolution of Nitrogen Fixation
Bayesian inferred phylogenetic reconstruction of Anf/Vnf/NifD, BchN, and NflD proteins. The putative substrates and cofactors for each protein lineage are indicated below each respective clade.
A team of researchers supported by the NASA Astrobiology Institute (NAI) has proposed an new path in the evolution of biological nitrogen fixation on Earth. Nitrogen is one of the most important elements for life on Earth, and astrobiologists have long been interested in its role in the history and evolution of life.Nitrogen is abundant on our planet as an atmospheric gas. However, in order for Nitrogen to be accessible for life, it must be converted into other chemical forms. A key step in the global cycling of nitrogen is biological nitrogen fixation,...
February 8, 2012 / Posted by: Aaron Gronstal
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Cycling Nitrogen in Ancient Oceans
The nitrogen synthase complex. Nitrogenase is shown in the center, with two chains in cyan and two chains in grey. Image Credit: University of Arizona
In recent years, scientists have found evidence that a ‘near complete’ biological nitrogen cycle existed in the oceans during the late Archean to early Proterozoic (from 2.5 to 2 billion years ago). Modern bacteria use an enzyme called nitrogenase to cycle nitrogen from one form to another. This enzyme is dependent on the presence of metallic elements like iron (Fe), vanadium (V) and, most often, molybdenum (Mo). However, ancient oceans didn’t contain much molybdenum. Could Fe-nitrogenase or V-nitrogenase have played a larger role in the archaean oceans than they do today? To answer this question, a team...Source: [Geobiology]
July 1, 2011 / Posted by: Aaron Gronstal
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Cycling Nitrogen
NASA-funded researchers at the University of Washington have shown that microorganisms completed large-scale steps in the their evolution by 2.5 billion years ago. This means that the major branches of microbial life were before we have any record of them. One important aspect of this evolution was the development of microbes capable of fixing nitrogen. This metabolic pathway had profound effects on the environment of Earth and the evolution of all life on our planet.
Source: [Astrobiology Magazine]
February 22, 2009 / Posted by: Aaron Gronstal
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