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Halomebacteria
Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. Halobacteria are now recognized as archaea rather than bacteria and are one of the largest groups. The name 'halobacteria' was assigned to this group of organisms before the existence of the domain Archaea was realized, and while valid according to taxonomic rules, should be updated. Halophilic archaea are generally referred to as haloarchaea to distinguish them from halophilic bacteria. These microorganisms are among the halophile organisms, that they require high salt concentrations to grow, with most species requiring more than 2.0M NaCl for growth and survival. They are a distinct evolutionary branch of the Archaea distinguished by the possession of ether-linked lipids and the absence of murein in their cell walls. Haloarchaea can grow aerobically or anaerobically. Parts of the membranes of haloarchaea ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halobacterium
''Halobacterium'' (common abbreviation ''Hbt.'') is a genus in the family Halobacteriaceae. The genus ''Halobacterium'' ("salt" or "ocean bacterium") consists of several species of Archaea with an aerobic metabolism which requires an environment with a high concentration of salt; many of their proteins will not function in low-salt environments. They grow on amino acids in their aerobic conditions. Their cell walls are also quite different from those of bacteria, as ordinary lipoprotein membranes fail in high salt concentrations. In shape, they may be either rods or cocci, and in color, either red or purple. They reproduce using binary fission (by constriction), and are motile. ''Halobacterium'' grows best in a 42 °C environment. The genome of an unspecified ''Halobacterium'' species, sequenced by Shiladitya DasSarma, comprises 2,571,010 bp (base pairs) of DNA compiled into three circular strands: one large chromosome with 2,014,239 bp, and two smaller ones with 191,346 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halophile
The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, such as the alga '' Dunaliella salina'' and fungus '' Wallemia ichthyophaga''. Some well-known species give off a red color from carotenoid compounds, notably bacteriorhodopsin. Halophiles can be found in water bodies with salt concentration more than five times greater than that of the ocean, such as the Great Salt Lake in Utah, Owens Lake in California, the Urmia Lake in Iran, the Dead Sea, and in evaporation ponds. They are theorized to be a possible analogues for modeling extremophiles that might live in the salty subsurface water ocean of Jupiter's Europa and similar moons. Classification Halophiles are categorized by the extent of their halotolerance: slight, moderate, or extreme. Slight halophiles prefer 0.3 to 0.8 M (1.7 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halococcaceae
''Halococcaceae'' is a family of halophilic and mostly chemoorganotrophic archaea within the order '' Halobacteriales''. The type genus of this family is ''Halococcus.'' Its biochemical characteristics are the same as the order '' Halobacteriales.'' The name ''Halococcaceae'' is derived from the Latin term ''Halococcus,'' referring to the type genus of the family and the suffix "-ceae", an ending used to denote a family. Together, ''Halococcaceae'' refers to a family whose nomenclatural type is the genus ''Halococcus.'' Current Taxonomy and Molecular Signatures As of 2021, ''Halococcaceae'' contains a single validly published genus, ''Halococcus''. This family can be molecularly distinguished from other Halobacteria by the presence of 23 conserved signature proteins (CSPs) and nine conserved signature indels (CSIs) present in the following proteins: DNA gyrase subunit B, chaperone protein DnaK, HAD-superfamily hydrolase, glycosyltransferase, 2-Succinyl-6-hydroxy-2,4-cyclohe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halobacteriaceae
In taxonomy, the Halobacteriaceae are a family of the Halobacteriales in the domain Archaea.See the NCBIbr>webpage on Halobacteriaceae Data extracted from the ''Halobacteriaceae'' represent a large part of halophilic Archaea, along with members in two other methanogenic families, ''Methanosarcinaceae'' and ''Methanocalculaceae''. The family consists of many diverse genera that can survive extreme environmental niches. Most commonly, Halobacteriaceae are found in hypersaline lakes and can even tolerate sites polluted by heavy metals. They include neutrophiles, acidophiles (ex. ''Halarchaeum acidiphilum''), alkaliphiles (ex. ''Natronobacterium''), and there have even been psychrotolerant species discovered (ex. ''Hrr. lacusprofundi''). Some members have been known to live aerobically, as well as anaerobically, and they come in many different morphologies. These diverse morphologies include rods in genus Halobacterium, cocci in Halococcus, flattened discs or cups in Halofer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haloarculaceae
''Haloarculaceae'' is a family of halophilic and mostly chemoorganotrophic archaea within the order ''Halobacteriales''. The type genus of this family is ''Haloarcula.'' Its biochemical characteristics are the same as the order ''Halobacteriales.'' The name ''Haloarculaceae'' is derived from the Latin term ''Haloarcula,'' referring to the type genus of the family and the suffix "-ceae," an ending used to denote a family. Together, ''Haloarculaceae'' refers to a family whose nomenclatural type is the genus ''Haloarcula.'' Current Taxonomy and Molecular Signatures As of 2021, ''Haloarculaceae'' contains 10 validly published genera. This family can be molecularly distinguished from other Halobacteria by the presence of 19 conserved signature proteins (CSPs) and seven conserved signature indels (CSIs) present in the following proteins: acetylglutamate kinase, ribonuclease R, metallo-beta-lactamase, tRNA modifying enzyme, carbamoyl phosphate synthase large subunit and hypothetical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to absorb energy from light. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. The presence of magnesium in chlorophyll was discovered in 1906, and was that element's first detection in living tissue. After initial work done by German ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodopsin
Rhodopsin, also known as visual purple, is a protein encoded by the RHO gene and a G-protein-coupled receptor (GPCR). It is the opsin of the rod cells in the retina and a light-sensitive receptor protein that triggers visual phototransduction in rods. Rhodopsin mediates dim light vision and thus is extremely sensitive to light. When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 30 minutes, after which the rods are more sensitive. Defects in the rhodopsin gene cause eye diseases such as retinitis pigmentosa and congenital stationary night blindness. Names Rhodopsin was discovered by Franz Christian Boll in 1876. The name rhodospsin derives from Ancient Greek () for "rose", due to its pinkish color, and () for "sight". It was coined in 1878 by the German physiologist Wilhelm Friedrich Kühne (1837-1900). When George Wald discovered that rhodopsin is a holoprotein, consisting of retinal and an apoprotein, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinal
Retinal (also known as retinaldehyde) is a polyene chromophore. Retinal, bound to proteins called opsins, is the chemical basis of visual phototransduction, the light-detection stage of visual perception (vision). Some microorganisms use retinal to convert light into metabolic energy. In fact, a recent study suggests most living organisms on our planet ~3 billion years ago used retinal to convert sunlight into energy rather than chlorophyll. Since retinal absorbs mostly green light and transmits purple light, this gave rise to the Purple Earth Hypothesis. There are many forms of vitamin A — all of which are converted to retinal, which cannot be made without them. Retinal itself is considered to be a form of vitamin A when eaten by an animal. The number of different molecules that can be converted to retinal varies from species to species. Retinal was originally called retinene, and was renamed after it was discovered to be vitamin A aldehyde. Vertebrate animals ingest retin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriorhodopsin
Bacteriorhodopsin is a protein used by Archaea, most notably by haloarchaea, a class of the Euryarchaeota. It acts as a proton pump; that is, it captures light energy and uses it to move protons across the membrane out of the cell. The resulting proton gradient is subsequently converted into chemical energy. Function Bacteriorhodopsin is a light-driven H+ ion transporter found in some haloarchaea, most notably ''Halobacterium salinarum'' (formerly known as syn. ''H. halobium''). The proton-motive force generated by the protein is used by ATP synthase to generate adenosine triphosphate (ATP). By expressing bacteriorhodopsin, the archaea cells are able to synthesise ATP in the absence of a carbon source. Structure Bacteriorhodopsin is a 27 kDa integral membrane protein usually found in two-dimensional crystalline patches known as "purple membrane", which can occupy almost 50% of the surface area of the archaeal cell. The repeating element of the hexagonal lattice is compose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Membrane
A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates the interior of a cell from the external environment or creates intracellular compartments by serving as a boundary between one part of the cell and another. Biological membranes, in the form of eukaryotic cell membranes, consist of a phospholipid bilayer with embedded, integral and peripheral proteins used in communication and transportation of chemicals and ions. The bulk of lipids in a cell membrane provides a fluid matrix for proteins to rotate and laterally diffuse for physiological functioning. Proteins are adapted to high membrane fluidity environment of the lipid bilayer with the presence of an annular lipid shell, consisting of lipid molecules bound tightly to the surface of integral membrane proteins. The cell membranes are different from the isolating tissues formed by layers of cells, such as mucous membranes, basement membranes, and serous membranes. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Respiration
Cellular respiration is the process by which biological fuels are oxidised in the presence of an inorganic electron acceptor such as oxygen to produce large amounts of energy, to drive the bulk production of ATP. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy. Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction, it is an unusual one because of the slow, controlled release of energy from the series of reactions. Nutrients that are commonly used by animal and pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
