|
Methanotroph
Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to survive. Methanotrophs are especially common in or near environments where methane is produced, although some methanotrophs can oxidize atmospheric methane. Their habitats include wetlands, soils, marshes, rice paddies, landfills, aquatic systems (lakes, oceans, streams) and more. They are of special interest to researchers studying global warming, as they play a significant role in the global methane budget, by reducing the amount of methane emitted to the atmosphere. Methanotrophy is a special case of methylotrophy, using single-carbon compounds that are more reduced than carbon dioxide. Some methylotrophs, however, can also make use of multi-carbon compounds; this differentiates them from methanotrophs, which are usually fastidious metha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prokaryote
A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connections". Pearson Education. San Francisco: 2003. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: ''Bacteria'' (formerly Eubacteria) and ''Archaea'' (formerly Archaebacteria). Organisms with nuclei are placed in a third domain, Eukaryota. In the study of the origins of life, prokaryotes are thought to have arisen before eukaryotes. Besides the absence of a nucleus, prokaryotes also lack mitochondria, or most of the other membrane-bound organelles that characterize the eukaryotic cell. It was once thought that prokaryotic cellular components within the cytop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia-oxidizing Bacteria
Nitrifying bacteria are lithotroph, chemolithotrophic organisms that include species of genera such as ''Nitrosomonas'', ''Nitrosococcus'', ''Nitrobacter'', ''Nitrospina'', ''Nitrospira'' and ''Nitrococcus''. These bacteria get their energy from the redox, oxidation of inorganic nitrogen compounds. Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase (which oxidizes ammonia to hydroxylamine), hydroxylamine oxidoreductase (which oxidizes hydroxylamine to nitric oxide - which is further oxidized to nitrite by a currently unidentified enzyme), and nitrite oxidoreductase (which oxidizes nitrite to nitrate). Ecology Nitrifying bacteria are present in distinct taxonomical groups and are found in highest numbers where considerable amounts of ammonia are present (such as areas with extensive protein decomposit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binning (metagenomics)
In metagenomics, binning is the process of grouping reads or contigs and assigning them to individual genome. Binning methods can be based on either compositional features or alignment (similarity), or both. Introduction Metagenomic samples can contain reads from a huge number of organisms. For example, in a single gram of soil, there can be up to 18000 different types of organisms, each with its own genome. Metagenomic studies sample DNA from the whole community, and make it available as nucleotide sequences of certain length. In most cases, the incomplete nature of the obtained sequences makes it hard to assemble individual genes, much less recovering the full genomes of each organism. Thus, binning techniques represent a "best effort" to identify reads or contigs within certain genome known as Metagenome Assembled Genome (MAG). Taxonomy of MAGs can be inferred through placement into reference phylogenetic tree using algorithms like GTDB-Tk. The first studies that sampled DN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixotroph
A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other. It is estimated that mixotrophs comprise more than half of all microscopic plankton. There are two types of eukaryotic mixotrophs: those with their own chloroplasts, and those with endosymbionts—and those that acquire them through kleptoplasty or by enslaving the entire phototrophic cell. Possible combinations are photo- and chemotrophy, litho- and organotrophy (osmotrophy, phagotrophy and myzocytosis), auto- and heterotrophy or other combinations of these. Mixotrophs can be either eukaryotic or prokaryotic. They can take advantage of different environmental conditions. If a trophic mode is obligate, then it is always necessary for sustaining growth and maintenance; if facultative, it can be used as a supplemental source. Some organisms have incomplete Calvin cycles, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verrucomicrobiota
Verrucomicrobiota is a phylum of Gram-negative bacteria that contains only a few described species. The species identified have been isolated from fresh water, marine and soil environments and human faeces. A number of as-yet uncultivated species have been identified in association with eukaryotic hosts including extrusive explosive ectosymbionts of protists and endosymbionts of nematodes residing in their gametes. Verrucomicrobiota are abundant within the environment, though relatively inactive. This phylum is considered to have two sister phyla: Chlamydiota (formerly Chlamydiae) and Lentisphaerota (formerly Lentisphaerae) within the PVC superphylum. The Verrucomicrobiota phylum can be distinguished from neighbouring phyla within the PVC group by the presence of several conserved signature indels (CSIs). These CSIs represent unique, synapomorphic characteristics that suggest common ancestry within Verrucomicrobiota and an independent lineage amidst other bacteria. CSIs have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beijerinckiaceae
The Beijerinckiaceae are a family of Hyphomicrobiales named after the Dutch microbiologist Martinus Willem Beijerinck. ''Beijerinckia'' is a genus of free-living aerobic nitrogen-fixing bacteria. Acidotolerant ''Beijerinckiaceae'' has been shown to be the main bacterial methanol sink in a deciduous forest soil and highlights their importance for the conversion of methanol in forest soils. Together with ''Methylocystaceae'' they are alphaproteobacterial methanotroph Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to s ...s. References Hyphomicrobiales Martinus Beijerinck {{Hyphomicrobiales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylocystaceae
The Methylocystaceae are a family of bacteria that are capable of obtaining carbon and energy from methane. Such bacteria are called methanotrophs, and in particular the Methylocystaceae comprise the type II methanotrophs, which are structurally and biochemically distinct from the Methylococcaceae or type I methanotrophs. In this family methane is oxidized to form formaldehyde, which is assimilated by the serine pathway. This involves combining formaldehyde and glycine to form serine, which may be converted into glyceraldehyde and thus into other organic molecules. They can also fix nitrogen, like many other members of the order Hyphomicrobiales The ''Hyphomicrobiales'' are an order of Gram-negative Alphaproteobacteria. The rhizobia, which fix nitrogen and are symbiotic with plant roots, appear in several different families. The four families ''Nitrobacteraceae'', ''Hyphomicrobiaceae' .... The cells contained paired internal membranes which are arranged towards their peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylococcaceae
The Methylococcaceae are a family of bacteria that obtain their carbon and energy from methane, called methanotrophs.. They comprise the type I methanotrophs, in contrast to the Methylocystaceae or type II methanotrophs. They belong to Gammaproteobacteria, and are typically given their own order. The Methylococcaceae have internal membranes in the form of flattened discs, perpendicular to the cell wall. Methane is oxidized to give formaldehyde, which is fixed by a process called the ribulose monophosphate (RuMP) cycle. Here formaldehyde is combined with sugar ribulose, producing hexulose. This, in turn, is broken down to produce glyceraldehyde, which is used to produce new ribulose and other organic compounds. Catabolism does not involve a complete citric acid cycle The citric acid cycle (CAC)—also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA deri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphaproteobacteria
Alphaproteobacteria is a class of bacteria in the phylum Pseudomonadota (formerly Proteobacteria). The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria. The Alphaproteobacteria are highly diverse and possess few commonalities, but nevertheless share a common ancestor. Like all ''Proteobacteria'', its members are gram-negative and some of its intracellular parasitic members lack peptidoglycan and are consequently gram variable. Characteristics The Alphaproteobacteria are a diverse taxon and comprises several phototrophic genera, several genera metabolising C1-compounds (''e.g.'', ''Methylobacterium'' spp.), symbionts of plants (''e.g.'', ''Rhizobium'' spp.), endosymbionts of arthropods (''Wolbachia'') and intracellular pathogens (''e.g. Rickettsia''). Moreover, the class is sister to the protomitochondrion, the bacterium that was engulfed by the eukaryotic ancestor and gave rise to the mitochondria, which are organelles in eukaryotic ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gammaproteobacteria
Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically important groups of bacteria belong to this class. It is composed by all Gram-negative microbes and is the most phylogenetically and physiologically diverse class of Proteobacteria. These microorganisms can live in several terrestrial and marine environments, in which they play various important roles, including ''extreme environments'' such as hydrothermal vents. They generally have different shapes - rods, curved rods, cocci, spirilla, and filaments and include free living bacteria, biofilm formers, commensals and symbionts, some also have the distinctive trait of being bioluminescent. Metabolisms found in the different genera are very different; there are both aerobic and anaerobic (obligate or facultative) species, chemolithoautotrophic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
