Keratin in the context of "Sauropsida"

Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi, informally known as chytrids. The name is derived from the Ancient Greek χυτρίδιον (khutrídion), meaning "little pot", describing the structure containing unreleased zoospores. Chytrids are one of the earliest diverging fungal lineages, and their membership in kingdom Fungi is demonstrated with chitin cell walls, a posterior whiplash flagellum, absorptive nutrition, use of glycogen as an energy storage compound, and synthesis of lysine by the α-amino adipic acid (AAA) pathway.

Chytrids are saprobic, degrading refractory materials such as chitin and keratin, and sometimes act as parasites. There has been a significant increase in the research of chytrids since the discovery of Batrachochytrium dendrobatidis, the causal agent of chytridiomycosis.

Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (/fɒlɪˈdoʊtə/). The one extant family, the Manidae, has three genera: Manis, Phataginus, and Smutsia. Manis comprises four species found in Asia, while Phataginus and Smutsia include two species each, all found in sub-Saharan Africa. These species range in size from 30 to 100 cm (12 to 39 in). Several extinct pangolin species are also known. In September 2023, nine species were reported.

Pangolins have large, protective keratin scales, similar in material to fingernails and toenails, covering their skin; they are the only known mammals with this feature. Depending on the species, they live in hollow trees or burrows. Pangolins are nocturnal, and their diet consists of mainly ants and termites, which they capture using their long tongues. They tend to be solitary animals, meeting only to mate and produce a litter of one to three offspring, which they raise for about two years. Pangolins superficially resemble armadillos, though the two are not closely related; they have undergone convergent evolution.

William Thomas Astbury FRS (25 February 1898 – 4 June 1961) was an English physicist and molecular biologist who made pioneering X-ray diffraction studies of biological molecules. His work on keratin provided the foundation for Linus Pauling's discovery of the α-helix. He also studied the structure for DNA in 1937 and made the first step in the elucidation of its structure.

In zoology, a scale (Ancient Greek: λεπίς, romanized: lepís; Latin: squāma) is a small rigid plate made out of keratin that grows out of vertebrate animals' skin to provide protection. In lepidopterans (butterflies and moths), scales are plates on the surface of the insect wing, made out of chitin instead of keratin, and provide coloration. Scales are quite common and have evolved multiple times through convergent evolution, with varying structure and function.

Scales are generally classified as part of an organism's integumentary system. There are various types of scales according to the shape and class of an animal.

Turtles (order Testudines) are reptiles characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked turtles), which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins. They are found on most continents, some islands and, in the case of sea turtles, much of the ocean. Like other amniotes (reptiles, birds, and mammals) they breathe air and do not lay eggs underwater, although many species live in or around water.

Turtle shells are made mostly of bone; the upper part is the domed carapace, while the underside is the flatter plastron or belly-plate. Its outer surface is covered in scales made of keratin, the material of hair, horns, and claws. The carapace bones develop from ribs that grow sideways and develop into broad flat plates that join up to cover the body. Turtles are ectotherms or "cold-blooded", meaning that their internal temperature varies with their direct environment. They are generally opportunistic omnivores and mainly feed on plants and animals with limited movement. Many turtles migrate short distances seasonally. Sea turtles are the only reptiles that migrate long distances to lay their eggs on a favored beach.

Bovidae is the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and goat-antelopes such as sheep and goats. There are 143 extant species and 300 known extinct species of bovids, which are divided into either 11 major subfamilies, or two subfamilies with thirteen tribes. The earliest known bovid had evolved by 20 million years ago, in the early Miocene.

The bovids show great variation in size and colouration of their fur. With exceptions in some domesticated forms, all male bovids have two or more horns, and in many species, females possess horns too. The size and shape of the horns vary greatly, but the basic structure is always one or more pairs of simple, unbranched, bony protrusions of the skull covered in a permanent sheath of keratin, and often with a spiral, twisted, or fluted shape, Most bovids bear 30 to 32 teeth.

Chitin (C₈H₁₃O₅N)_n (/ˈkaɪtɪn/ KY-tin) is a long-chain polymer of N-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chitin are produced each year in the biosphere. It is a primary component of cell walls in fungi (especially filamentous and mushroom-forming fungi), the exoskeletons of arthropods such as crustaceans and insects, the radulae, cephalopod beaks and gladii of molluscs and in some nematodes and diatoms.It is also synthesised by at least some fish and lissamphibians. Commercially, chitin is extracted from the shells of crabs, shrimps, shellfish and lobsters, which are major by-products of the seafood industry. The structure of chitin is comparable to cellulose, forming crystalline nanofibrils or whiskers. It is functionally comparable to the protein keratin. Chitin has proved useful for several medicinal, industrial and biotechnological purposes.

Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. After cells of interest have been isolated from living tissue, they can subsequently be maintained under carefully controlled conditions. They need to be kept at body temperature (37 °C) in an incubator. These conditions vary for each cell type, but generally consist of a suitable vessel with a substrate or rich medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases (CO₂, O₂), and regulates the physio-chemical environment (pH buffer, osmotic pressure, temperature). Most cells require a surface or an artificial substrate to form an adherent culture as a monolayer (one single-cell thick), whereas others can be grown free floating in a medium as a suspension culture. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar. Tissue culture commonly refers to the culture of animal cells and tissues, with the more specific term plant tissue culture being used for plants. The lifespan of most cells is genetically determined, but some cell-culturing cells have been 'transformed' into immortal cells which will reproduce indefinitely if the optimal conditions are provided.

In practice, the term "cell culture" now refers to the culturing of cells derived from multicellular eukaryotes, especially animal cells, in contrast with other types of culture that also grow cells, such as plant tissue culture, fungal culture, and microbiological culture (of microbes). The historical development and methods of cell culture are closely interrelated with those of tissue culture and organ culture. Viral culture is also related, with cells as hosts for the viruses.

A horn is a permanent pointed projection on the head of various animals that consists of a covering of keratin and other proteins surrounding a core of live bone. Horns are distinct from antlers, which are not permanent. In mammals, true horns are found mainly among the ruminant artiodactyls, in the families Antilocapridae (pronghorn) and Bovidae (cattle, goats, antelope etc.). Cattle horns arise from subcutaneous connective tissue (under the scalp) and later fuse to the underlying frontal bone.

One pair of horns is usual; however, two or more pairs occur in a few wild species and in some domesticated breeds of sheep. Polycerate (multi-horned) sheep breeds include the Hebridean, Icelandic, Jacob, Manx Loaghtan, and the Navajo-Churro.