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Nitrososphaeria
The Nitrososphaerota (syn. Thaumarchaeota) are a phylum of the Archaea proposed in 2008 after the genome of ''Cenarchaeum symbiosum'' was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota (formerly Crenarchaeota). Three described species in addition to ''C. symbiosum'' are ''Nitrosopumilus maritimus'', ''Nitrososphaera viennensis'', and ''Nitrososphaera gargensis''. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea ''Nitrosopumilus maritimus'' and ''Nitrososphaera gargensis'', concluding that these species form a distinct lineage that includes ''Cenarchaeum symbiosum''. The lipid crenarchaeol has been found only in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrososphaeria
The Nitrososphaerota (syn. Thaumarchaeota) are a phylum of the Archaea proposed in 2008 after the genome of ''Cenarchaeum symbiosum'' was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota (formerly Crenarchaeota). Three described species in addition to ''C. symbiosum'' are ''Nitrosopumilus maritimus'', ''Nitrososphaera viennensis'', and ''Nitrososphaera gargensis''. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea ''Nitrosopumilus maritimus'' and ''Nitrososphaera gargensis'', concluding that these species form a distinct lineage that includes ''Cenarchaeum symbiosum''. The lipid crenarchaeol has been found only in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrososphaerales
The Nitrososphaerota (syn. Thaumarchaeota) are a phylum of the Archaea proposed in 2008 after the genome of ''Cenarchaeum symbiosum'' was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota (formerly Crenarchaeota). Three described species in addition to ''C. symbiosum'' are ''Nitrosopumilus maritimus'', ''Nitrososphaera viennensis'', and ''Nitrososphaera gargensis''. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea ''Nitrosopumilus maritimus'' and ''Nitrososphaera gargensis'', concluding that these species form a distinct lineage that includes ''Cenarchaeum symbiosum''. The lipid crenarchaeol has been found only in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrososphaera Gargensis
''Nitrososphaera gargensis'' is a non-pathogenic, small coccus measuring 0.9 ± 0.3 μm in diameter. ''N. gargensis'' is observed in small abnormal cocci groupings and uses its archaella to move via chemotaxis. Being an Archaeon, ''Nitrososphaera gargensis'' has a cell membrane composed of crenarchaeol, its isomer, and a distinct glycerol dialkyl glycerol tetraether (GDGT), which is significant in identifying ammonia-oxidizing archaea (AOA). The organism plays a role in influencing ocean communities and food production.Courtens, Emilie Np, Eva Spieck, Ramiro Vilchez-Vargas, Samuel Bodé, Pascal Boeckx, Stefan Schouten, Ruy Jauregui, Dietmar H. Pieper, Siegfried E. Vlaeminck, and Nico Boon. "A Robust Nitrifying Community in a Bioreactor at 50 °C Opens up the Path for Thermophilic Nitrogen Removal." ''The ISME Journal'' (2016) http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej20168a.htm Discovery ''Nitrososphaera gargensis'' was discovered in a Garga hot spring in Siberia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrososphaera Viennensis
''Nitrososphaera'' is a mesophilic genus of ammonia-oxidizing Crenarchaeota. The first ''Nitrososphaera'' organism was discovered in garden soils at the University of Vienna leading to the categorization of a new genus, family, order and class of Archaea. This genus is contains three distinct species: '' N. viennensis, Ca. N. gargensis'', and ''Ca N. evergladensis''. ''Nitrososphaera'' are chemolithoautotrophs and have important biogeochemical roles as nitrifying organisms. Phylogeny The ''Nitrososphaera'' genus contains one of the first discovered ammonia-oxidizing archaea (''N. viennensis)''. Only three distinct species of this genus have been identified. Both ''Ca. N. gargensis'', and ''Ca N. Evergladensis'' are known as ''Candidatus,'' which have been discovered and analyzed but have yet been studied in pure culture in a lab. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrosopumilus Maritimus
''Nitrosopumilus maritimus'' is an extremely common archaeon living in seawater. It is the first member of the Group 1a Nitrososphaerota (formerly Thaumarchaeota) to be isolated in pure culture. Gene sequences suggest that the Group 1a Nitrososphaerota are ubiquitous with the oligotrophic surface ocean and can be found in most non-coastal marine waters around the planet. It is one of the smallest living organisms at 0.2 micrometers in diameter. Cells in the species ''N. maritimus'' are shaped like peanuts and can be found both as individuals and in loose aggregates. They oxidize ammonia to nitrite and members of ''N. maritimus'' can oxidize ammonia at levels as low as 10 nanomolar, near the limit to sustain its life. Archaea in the species ''N. maritimus'' live in oxygen-depleted habitats. Oxygen needed for ammonia oxidation might be produced by novel pathway which generates oxygen and dinitrogen. ''N. maritimus'' is thus among organisms which are able to produce oxygen in dark. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Cycle
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmospheric nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is both caust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeochemical Cycle
A biogeochemical cycle (or more generally a cycle of matter) is the pathway by which a chemical substance cycles (is turned over or moves through) the biotic and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, hydrosphere and lithosphere. There are biogeochemical cycles for chemical elements, such as for calcium, carbon, hydrogen, mercury, nitrogen, oxygen, phosphorus, selenium, iron and sulfur, as well as molecular cycles, such as for water and silica. There are also macroscopic cycles, such as the rock cycle, and human-induced cycles for synthetic compounds such as polychlorinated biphenyls (PCBs). In some cycles there are reservoirs where a substance can remain or be sequestered for a long period of time. Overview Energy flows directionally through ecosystems, entering as sunlight (or inorganic molecules for chemoautotrophs) and leaving as heat during the many transfers between trophic levels. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metagenomics
Metagenomics is the study of genetic material recovered directly from environmental or clinical samples by a method called sequencing. The broad field may also be referred to as environmental genomics, ecogenomics, community genomics or microbiomics. While traditional microbiology and microbial genome sequencing and genomics rely upon cultivated clonal cultures, early environmental gene sequencing cloned specific genes (often the 16S rRNA gene) to produce a profile of diversity in a natural sample. Such work revealed that the vast majority of microbial biodiversity had been missed by cultivation-based methods. Because of its ability to reveal the previously hidden diversity of microscopic life, metagenomics offers a powerful lens for viewing the microbial world that has the potential to revolutionize understanding of the entire living world. As the price of DNA sequencing continues to fall, metagenomics now allows microbial ecology to be investigated at a much greater scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and Earth's atmosphere, atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration to and release from carbon sinks. Carbon sinks in the land and the ocean each currently take up about one-quarter of anthropogenic carbon emissions each year. Humans have disturbed the biological carbon cycle for many centuries by modifying land use, and moreover with the recent industrial-scale mining of fossil carbon (coal, petroleum and natural gas, gas extraction, and cement manufacture) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crenarchaeol
Crenarchaeol is a glycerol biphytanes glycerol tetraether (GDGT) biological membrane lipid. Together with archaeol, crenarcheol comprises a major component of archaeal membranes. Archaeal membranes are distinct from those of bacteria and eukaryotes because they contain isoprenoid GDGTs instead of diacyl lipids, which are found in the other domains (bacteria, procarya). It has been proposed that GDGT membrane lipids are an adaptation to the high temperatures present in the environments that are home to extremophile archaea Discovery and distribution Archaeal GDGTs were first detected in pelagic waters. Unknown GDGTs were also found in marine sediments and isolated from ''Cenarchaeum symbiosum'', a marine ammonia-oxidizing archaeon that lives in symbiosis with sponges. Following the discovery of GDGTs outside of hydrothermal environments, crenarchaeol was first identified as the major GDGT component in surface sediments and extracts from ''C. symbiosum'' by two-dimensional nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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