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CD1d Receptor
CD1D is the human gene that encodes the protein CD1d, a member of the CD1 (cluster of differentiation 1) family of glycoproteins expressed on the surface of various human antigen-presenting cells. They are non-classical MHC proteins, related to the class I MHC proteins, and are involved in the presentation of lipid antigens to T cells. CD1d is the only member of the group 2 CD1 molecules. Biological significance CD1d-presented lipid antigens activate a special class of T cells, known as natural killer T (NKT) cells, through the interaction with the T-cell receptor present on NKT membranes. When activated, NKT cells rapidly produce Th1 and Th2 cytokines, typically represented by interferon-gamma and interleukin 4 production. Nomenclature CD1d is also known as R3G1 Ligands Some of the known ligands for CD1d are: * α-galactosylceramide (α-GalCer), a compound originally derived from the marine sponge ''Agelas mauritanius'' with no physiological role but great research utili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically moder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agelas
''Agelas'' is a genus of sea sponge in the class Demospongiae. Ecology and distribution Members of this genus are filter feeders. and occur in the West Indies, the Mediterranean Sea, the Red Sea and the Indian Ocean in shallow tropical and subtropical waters down to a depth of or exceptionally . Spicules Some authorities report that the spongin fibres contain no coring spicules Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ... while others report that there are some of variable length. Fernando Parra-Velandia however, describing the Caribbean species in the group, writes that "The presence of verticillated acanthostyle spicules and a fibroreticulate skeleton of spongin fibres cored and/or echinated by spicules characterize this group." Species The World Register of Marine Speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetramers
A tetramer () (''tetra-'', "four" + '' -mer'', "parts") is an oligomer formed from four monomers or subunits. The associated property is called ''tetramery''. An example from inorganic chemistry is titanium methoxide with the empirical formula Ti(OCH3)4, which is tetrameric in solid state and has the molecular formula Ti4(OCH3)16. An example from organic chemistry is kobophenol A, a substance that is formed by combining four molecules of resveratrol. In biochemistry, it similarly refers to a biomolecule formed of four units, that are the same (homotetramer), i.e. as in Concanavalin A or different (heterotetramer), i.e. as in hemoglobin. Hemoglobin has 4 similar sub-units while immunoglobulins have 2 very different sub-units. The different sub-units may have each their own activity, such as binding biotin in avidin tetramers, or have a common biological property, such as the allosteric binding of oxygen in hemoglobin. See also * Cluster chemistry; atomic and molecular clusters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclitol
In organic chemistry, a cyclitol is a cycloalkane containing at least three hydroxyl, each attached to a different ring carbon atom. The general formula for an unsubstituted cyclitol is or where 3 ≤ ''x'' ≤ ''n''. The name is also used for compounds that can be viewed as result of substituting various functional groups for the hydrogen atoms in such a molecule, as well as similar molecules with one or more double bonds in the ring. Cyclitols and their derivatives are some of the compatible solutes which are formed in a plant as a response to salt or water stress. Some cyclitols (e.g. quinic or shikimic acid) are parts of hydrolysable tannins. Isomerism and nomenclature Unsubstituted cyclitols with the same ring size and number of hydroxyls may exist in several structural isomers, depending on the position of the hydroxyls along the ring. For example, cyclohexanetriol exists in three distinct isomers (1,2,3-, 1,2,4-, and 1,3,5-). Furthermore, the hydrogen and the hydroxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IGb3
Isoglobotriosylceramide, Gal(α1→3)Gal(β1→4) Glcβ(1→1) Cer, abbreviated as iGb3, is an iso-globo-series of glycosphingolipid, which mysteriously disappeared in most mammals studied (pig, mouse, and human), except trace amount reported in the thymus. iGb3 was discovered in canine and rat intestines among iso-globo-series of glycosphingolipids. First NMR spectrums for standard iGb3 were published by Dr. Tomoya Ogawa. The physiological function of iGb3 is not clear. It has been identified as a CD1d- presented self-antigen for an innate type of immune cells termed as Natural Killer T (NKT) cells. Extensive biochemical studies by multiple methods including HPLC, mass spectrometry, and NMR Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with ... did not lead to positive finding of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invariant NKT
Invariant and invariance may refer to: Computer science * Invariant (computer science), an expression whose value doesn't change during program execution ** Loop invariant, a property of a program loop that is true before (and after) each iteration * A data type in method overriding that is neither covariant nor contravariant * Class invariant, an invariant used to constrain objects of a class Physics, mathematics, and statistics * Invariant (mathematics), a property of a mathematical object that is not changed by a specific operation or transformation ** Rotational invariance, the property of function whose value does not change when arbitrary rotations are applied to its argument ** Scale invariance, a property of objects or laws that do not change if scales of length, energy, or other variables, are multiplied by a common factor ** Topological invariant * Invariant (physics), something does not change under a transformation, such as from one reference frame to another * Invaria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen-presenting Cells
An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). APCs process antigens and present them to T-cells. Almost all cell types can present antigens in some way. They are found in a variety of tissue types. Professional antigen-presenting cells, including macrophages, B cells and dendritic cells, present foreign antigens to helper T cells, while virus-infected cells (or cancer cells) can present antigens originating inside the cell to cytotoxic T cells. In addition to the MHC family of proteins, antigen presentation relies on other specialized signaling molecules on the surfaces of both APCs and T cells. Antigen-presenting cells are vital for effective adaptive immune response, as the functioning of both cytotoxic and helper T cells is dependent on APCs. Antigen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as starch and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form of glucose is -glucose, while -glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an aldehyde group, and is therefore an aldohexose. The glucose molecule can exist in an open-chain (acyclic) as well as ring (cyclic) form. Gluco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterium
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationshi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', ''Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomonas
''Sphingomonas'' was defined in 1990 as a group of Gram-negative, rod-shaped, chemoheterotrophic, strictly aerobic bacteria. They possess ubiquinone 10 as their major respiratory quinone, contain glycosphingolipids (GSLs), specifically ceramide, instead of lipopolysaccharide (LPS) in their cell envelopes, and typically produce yellow-pigmented colonies. The GSL serves to protect the bacteria from antibacterial substances. Unlike most Gram-negative bacteria, ''Sphingomonas'' carries endotoxins and has a hydrophobic surface characterized by the short nature of the GSL's carbohydrate portion. By 2001, the genus included more than 20 species that were quite diverse in terms of their phylogenetic, ecological, and physiological properties. As a result, ''Sphingomonas'' was subdivided into different genera: ''Sphingomonas'', ''Sphingobium'', '' Novosphingobium'', '' Sphingosinicella'', and '' Sphingopyxis''. These genera are commonly referred to collectively as sphingomonads. Distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Wall
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism. Cell walls are absent in many eukaryotes, including animals, but are present in some other ones like fungi, algae and plants, and in most prokaryotes (except mollicute bacteria). A major function is to act as pressure vessels, preventing over-expansion of the cell when water enters. The composition of cell walls varies between taxonomic group and species and may depend on cell type and developmental stage. The primary cell wall of land plants is composed of the polysaccharides cellulose, hemicelluloses and pectin. Often, other polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess cell walls made of glycoproteins and polysaccharides such as carrageenan and agar that are absent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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