Chitin (C 8 H 13 n ( "English respelling pronunciation"> KY -tin ), long chain polymer N -acetylglucosamine, is a glucose derivative. It is a major component of cell walls in fungi, arthropod exoskeleton, such as crustaceans (eg, crabs, lobsters and shrimp) and insects, radula molluscs, cephalopoda beaks, and fish scales and lissamphibians. The structure of chitin is proportional to other polysaccharides - cellulose, forming a nanofibril or a crystal whisker. In terms of function, it may be compared to protein keratin. Chitin has proven useful for some medicinal, industrial and biotechnology purposes.
Video Chitin
Etimologi
The English word "chitin" comes from the French word chitine , originating from 1821 from the Greek word ????? (chiton), which means cover.
A similar word, "chiton", refers to a marine animal with a protective shell.
Maps Chitin
Chemistry, physical properties and biological functions
The chitin structure was determined by Albert Hofmann in 1929.
Chitin is a nitrogen-modified polysaccharide; it is synthesized from the N -acetyl- D -glucosamine unit (exactly, 2- (acetylamino) -2-deoxy- D -glukosa). These units form covalent? - (1-> 4) -linkages (similar to the relationship between the glucose unit forming cellulose). Therefore, chitin can be described as cellulose with one hydroxyl group in each monomer replaced by an acetyl amine group. This makes it possible to increase the hydrogen bond between adjacent polymers, providing a strengthening chitin-polymer matrix.
In its pure and unmodified form, chitin is translucent, supple, resilient, and hard enough. In most arthropods, however, they are often modified, occurring mostly as components of composite materials, such as in sclerotin, a brown proteinase matrix, which forms much of the insect's exoskeleton. Combined with calcium carbonate, as in crustaceans and mollusks, chitin produces a much stronger composite. This composite material is much harder and stiffer than pure chitin, and harder and less brittle than pure calcium carbonate. Another difference between pure form and composite can be seen by comparing the flexible body walls of the caterpillar (especially chitin) with the rigid beetle elytron of light (containing mostly sclerotin).
On the scale of the butterfly wings, chitin is organized into a gyroid pile made of photonic chitin crystals that produce various colors that serve phenotypic signals and communication for mating and foraging. The intricate gyroid chitin construction on the butterfly wings creates an optical device model that has the potential for innovation in biomimicry. The scarab beetle in the genus Cyphochilus also uses chitin to form very thin scales (five to fifteen micrometers thick) that diffusively reflect white light. This scale is a network of random chitin filaments with diameters on a scale of hundreds of nanometers, which serve to diffuse light. The scattering of many lights is thought to play a role in the unusual white of the scales. In addition, some social wasps, such as Protopolybia chartergoides , orally dispense chitin-containing material to strengthen the outer envelope envelope, which consists of paper.
Chitosan is produced commercially with deacetylation of chitin; chitosan dissolves in water, while chitin is not.
Nanofibrils have been made using chitin and chitosan.
Health effects
Chitin-producing organisms such as protozoa, fungi, arthropods, and nematodes are often pathogens in other species.
Other humans and mammals
Humans and other mammals have chitinase and chitinase proteins that can degrade chitin; they also have several immune receptors that can recognize chitin and its degradation products in molecular patterns associated with pathogens, initiating an immune response.
Chitin is felt mostly in the lungs or gastrointestinal tract where it can activate the innate immune system via eosinophils or macrophages, as well as adaptive immune responses through helper T cells. Keratinocytes in the skin can also react to chitin or chitin fragments. According to in vitro studies, chitin is felt by receptors, such as FIBCD1, KLRB1, REG3G, Toll-like 2 receptors, CLEC7A, and mannose receptors.
Immune responses can sometimes cleanse chitin and related organisms, but sometimes the immune response is pathological and allergic; allergic to home dust mites are thought to be driven by a response to chitin.
Plants
Plants also have receptors that can cause a response to chitin, the chitin elicitor receptor kinase 1 and the chitin-binding protein elititor. The first chitin receptor was cloned in 2006. When the receptor is activated by chitin, the genes associated with plant defense are expressed, and the hormone jasmonate is activated, which in turn activates the systematic defenses. Commensal mushrooms have a way to interact with host immune responses that by 2016 are not well understood.
Some pathogens produce chitin-binding proteins that cover the chitin they remove from this receptor. Zymoseptoria tritici is an example of a pathogenic fungus that has such blocking proteins; it is a major pest on wheat crops.
Fossil record
Chitin may be present in the Cambrian extraction of arthropods such as trilobites. The oldest chimpanzee preserved dates to Oligocene, about 25 million years ago , consisting of scorpions wrapped in amber.
Usage
Agriculture
Chitin is a good crop defense mechanism inducer for disease control. It has also been assessed as a fertilizer that can improve overall yields.
Industrial
Chitin is used in industry in many processes. Examples of potential use of chemically modified chitin in food processing include the formation of edible films and as additives to thicken and stabilize food. Process for size and strengthening paper using chitin and chitosan.
Research
How chitin interacts with the immune system of plants and animals has become an active research area, including the identity of key receptors interacting with chitin, whether the size of the chitin particle is relevant to the type of immune response that is triggered, and the mechanism used. immune system response. Chitin and chitosan have been explored as adjuvant vaccines because of its ability to stimulate the immune response.
Chitin and chitosan are being developed as scaffolds in the study of how tissues grow and how the wounds heal, and in an effort to create better bandages, surgical sutures, and materials for allotransplantation. The stitches made of chitin have been explored for years, but by 2015, nothing is on the market; lack of elasticity and thread-making problems has hindered commercial development.
By 2014, the method for using chitosan as a reproducible form of biodegradable plastic was introduced. Nanofiber Chitin is extracted from waste and crustacean fungi for possible product development in tissue engineering, medicine, and industry.
See also
- Biopesticides
- Chitobiose
- Lorica
- Sporopollenin
- Tektin
References
External links
Source of the article : Wikipedia
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