Melanins. Medical search

Insoluble polymers of TYROSINE derivatives found in and causing darkness in skin (SKIN PIGMENTATION), hair, and feathers providing protection against SUNBURN induced by SUNLIGHT. CAROTENES contribute yellow and red coloration.

An enzyme of the oxidoreductase class that catalyzes the reaction between L-tyrosine, L-dopa, and oxygen to yield L-dopa, dopaquinone, and water. It is a copper protein that acts also on catechols, catalyzing some of the same reactions as CATECHOL OXIDASE. EC 1.14.18.1.

Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.

Coloration of the skin.

Coloration or discoloration of a part by a pigment.

Melanin-containing organelles found in melanocytes and melanophores.

Naphthalene derivatives carrying one or more hydroxyl (-OH) groups at any ring position. They are often used in dyes and pigments, as antioxidants for rubber, fats, and oils, as insecticides, in pharmaceuticals, and in numerous other applications.

A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific.

General term for a number of inherited defects of amino acid metabolism in which there is a deficiency or absence of pigment in the eyes, skin, or hair.

A normally saprophytic mitosporic Chaetothyriales fungal genus. Infections in humans include PHAEOHYPHOMYCOSIS; and PERITONITIS.. Exophiala jeanselmei (previously Phialophora jeanselmei) is an etiological agent of MYCETOMA.

Excessive pigmentation of the skin, usually as a result of increased epidermal or dermal melanin pigmentation, hypermelanosis. Hyperpigmentation can be localized or generalized. The condition may arise from exposure to light, chemicals or other substances, or from a primary metabolic imbalance.

Found in large amounts in the plasma and urine of patients with malignant melanoma. It is therefore used in the diagnosis of melanoma and for the detection of postoperative metastases. Cysteinyldopa is believed to be formed by the rapid enzymatic hydrolysis of 5-S-glutathionedopa found in melanin-producing cells.

A copper-containing oxidoreductase enzyme that catalyzes the oxidation of 4-benzenediol to 4-benzosemiquinone. It also has activity towards a variety of O-quinols and P-quinols. It primarily found in FUNGI and is involved in LIGNIN degradation, pigment biosynthesis and detoxification of lignin-derived products.

A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.

An extensive order of basidiomycetous fungi whose fruiting bodies are commonly called mushrooms.

An enzyme of the oxidoreductase class that catalyzes the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. EC 1.10.3.1.

A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans.

Color of hair or fur.

Experimentally induced tumor that produces MELANIN in animals to provide a model for studying human MELANOMA.

Disorders of increased melanin pigmentation that develop without preceding inflammatory disease.

A basic helix-loop-helix leucine zipper transcription factor that regulates the CELL DIFFERENTIATION and development of a variety of cell types including MELANOCYTES; OSTEOCLASTS; and RETINAL PIGMENT EPITHELIUM. Mutations in MITF protein have been associated with OSTEOPETROSIS and WAARDENBURG SYNDROME.

Flat keratinous structures found on the skin surface of birds. Feathers are made partly of a hollow shaft fringed with barbs. They constitute the plumage.

A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)

A genus of cuttlefish in the family Sepiidae. They live in tropical, subtropical and temperate waters in most oceans.

Heterogeneous group of autosomal recessive disorders comprising at least four recognized types, all having in common varying degrees of hypopigmentation of the skin, hair, and eyes. The two most common are the tyrosinase-positive and tyrosinase-negative types.

The large pigment cells of fish, amphibia, reptiles and many invertebrates which actively disperse and aggregate their pigment granules. These cells include MELANOPHORES, erythrophores, xanthophores, leucophores and iridiophores. (In algae, chromatophores refer to CHLOROPLASTS. In phototrophic bacteria chromatophores refer to membranous organelles (BACTERIAL CHROMATOPHORES).)

Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms.

An unpigmented malignant melanoma. It is an anaplastic melanoma consisting of cells derived from melanoblasts but not forming melanin. (Dorland, 27th ed; Stedman, 25th ed)

A plant genus of the family FABACEAE.

Short-lived elementary particles found in cosmic radiation or produced from nuclear disintegration. Their mass is between that of protons and electrons and they can be negative, positive, or neutral. pi-Mesons (pions) are heavier than mu-mesons (muons) and are proposed for cancer radiotherapy because their capture and disintegration by matter produces powerful, but short-lived, secondary radiation.

Actinium. A trivalent radioactive element and the prototypical member of the actinide family. It has the atomic symbol Ac, atomic number 89, and atomic weight 227.0278. Its principal isotope is 227 and decays primarily by beta-emission.

The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.

A 13-amino acid peptide derived from proteolytic cleavage of ADRENOCORTICOTROPIC HORMONE, the N-terminal segment of ACTH. ACTH (1-13) is amidated at the C-terminal to form ACTH (1-13)NH2 which in turn is acetylated to form alpha-MSH in the secretory granules. Alpha-MSH stimulates the synthesis and distribution of MELANIN in MELANOCYTES in mammals and MELANOPHORES in lower vertebrates.

A genus of beetles which infests grain products. Its larva is called mealworm.

A mitosporic Loculoascomycetes fungal genus including several plant pathogens and at least one species which produces a highly phytotoxic antibiotic. Its teleomorph is Lewia.

Peptide hormones produced by NEURONS of various regions in the HYPOTHALAMUS. They are released into the pituitary portal circulation to stimulate or inhibit PITUITARY GLAND functions. VASOPRESSIN and OXYTOCIN, though produced in the hypothalamus, are not included here for they are transported down the AXONS to the POSTERIOR LOBE OF PITUITARY before being released into the portal circulation.

Enzymes of the isomerase class that catalyze the oxidation of one part of a molecule with a corresponding reduction of another part of the same molecule. They include enzymes converting aldoses to ketoses (ALDOSE-KETOSE ISOMERASES), enzymes shifting a carbon-carbon double bond (CARBON-CARBON DOUBLE BOND ISOMERASES), and enzymes transposing S-S bonds (SULFUR-SULFUR BOND ISOMERASES). (From Enzyme Nomenclature, 1992) EC 5.3.

Substances used to obtain a lighter skin complexion or to treat HYPERPIGMENTATION disorders.

Malformations of organs or body parts during development in utero.

Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.

Linear TETRAPYRROLES that give a characteristic color to BILE including: BILIRUBIN; BILIVERDIN; and bilicyanin.

Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)

Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.

The addition of descriptive information about the function or structure of a molecular sequence to its MOLECULAR SEQUENCE DATA record.

Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.

Large aggregates of CELESTIAL STARS; COSMIC DUST; and gas. (From McGraw Hill Dictionary of Scientific and Technical Terms, 6th ed)

A cell line derived from cultured tumor cells.

The ability of some cells or tissues to survive lethal doses of IONIZING RADIATION. Tolerance depends on the species, cell type, and physical and chemical variables, including RADIATION-PROTECTIVE AGENTS and RADIATION-SENSITIZING AGENTS.

A genus of gram-positive aerobic cocci found in the soil, that is highly resistant to radiation, especially ionizing radiation (RADIATION, IONIZING). Deinococcus radiodurans is the type species.

The human being as a non-anatomical and non-zoological entity. The emphasis is on the philosophical or artistic treatment of the human being, and includes lay and social attitudes toward the body in history. (From J. Cassedy, NLM History of Medicine Division)

Cellular localization and role of prohormone convertases in the processing of pro-melanin concentrating hormone in mammals. (1/1585)

Melanin concentrating hormone (MCH) and neuropeptide EI (NEI) are two peptides produced from the same precursor in mammals, by cleavage at the Arg145-Arg146 site and the Lys129-Arg130 site, respectively. We performed co-localization studies to reveal simultaneously the expression of MCH mRNA and proconvertases (PCs) such as PC1/3 or PC2. In the rat hypothalamus, PC2 was present in all MCH neurons, and PC1/3 was present in about 15-20% of these cells. PC1/3 or PC2 was not found in MCH-positive cells in the spleen. In GH4C1 cells co-infected with vaccinia virus (VV):pro-MCH along with VV:furin, PACE4, PC1/3, PC2, PC5/6A, PC5/6B, or PC7, we observed only efficient cleavage at the Arg145-Arg146 site to generate mature MCH. Co-expression of pro-MCH together with PC2 and 7B2 resulted in very weak processing to NEI. Comparison of pro-MCH processing patterns in PC1/3- or PC2-transfected PC12 cells showed that PC2 but not PC1/3 generated NEI. Finally, we analyzed the pattern of pro-MCH processing in PC2 null mice. In the brain of homozygotic mutants, the production of mature NEI was dramatically reduced. In contrast, MCH content was increased in the hypothalamus of PC2 null mice. In the spleen, a single large MCH-containing peptide was identified in both wild type and PC2 null mice. Together, our data suggest that pro-MCH is processed differently in the brain and in peripheral organs of mammals. PC2 is the key enzyme that produces NEI, whereas several PCs may cleave at the Arg145-Arg146 site to generate MCH in neuronal cell types. (+info)

Effects of lithium on pigmentation in the embryonic zebrafish (Brachydanio rerio). (2/1585)

Pigment cell precursors of the embryonic zebrafish give rise to melanophores, xanthophores and/or iridophores. Cell signaling mechanisms related to the development of pigmentation remain obscure. In order to examine the mechanisms involved in pigment cell signaling, we treated zebrafish embryos with various activators and inhibitors of signaling pathways. Among those chemicals tested, LiCl and LiCl/forskolin had a stimulatory effect on pigmentation, most notable in the melanophore population. We propose that the inositol phosphate (IP) pathway, is involved in pigment pattern formation in zebrafish through its involvement in the: (1) differentiation/proliferation of melanophores; (2) dispersion of melanosomes; and/or (3) synthesis/deposition of melanin. To discern at what level pigmentation was being effected we: (1) counted the number of melanophores in control and experimental animals 5 days after treatment; (2) measured tyrosinase activity and melanin content; and (3) employed immunoblotting techniques with anti-tyrosine-related protein-2 and anti-melanocyte-specific gene-1 as melanophore-specific markers. Although gross pigmentation increased dramatically in LiCl- and LiCl/forskolin treated embryos, the effect on pigmentation was not due to an increase in the proliferation of melanophores, but was possibly through an increase in melanin synthesis and/or deposition. Collectively, results from these studies suggest the involvement of an IP-signaling pathway in the stimulation of pigmentation in embryonic zebrafish through the synthesis/deposition of melanin within the neural crest-derived melanophores. (+info)

The effect of the orexins on food intake: comparison with neuropeptide Y, melanin-concentrating hormone and galanin. (3/1585)

Orexin-A and orexin-B (the hypocretins) are recently described neuropeptides suggested to have a physiological role in the regulation of food intake in the rat. We compared the orexigenic effect of the orexins administered intracerebroventricular (ICV) with other known stimulants of food intake, one strong, neuropeptide Y (NPY), and two weaker, melanin-concentrating hormone (MCH) and galanin. Orexin-A consistently stimulated food intake, but orexin-B only on occasions. Both peptides stimulated food intake significantly less than NPY, but to a similar extent to MCH (2 h food intake: NPY 3 nmol, 7.2+/-0.9 g vs saline, 1.5+/-0.2 g, P<0.001, MCH 3 nmol, 3.2+/-0.8 g vs saline, P<0.01, orexin-B 30 nmol, 2. 6+/-0.5 g vs saline, P=0.11) and to galanin (1 h food intake: galanin 3 nmol, 2.0+/-0.4 g vs saline, 0.8+/-0.2 g, P<0.05, orexin-A 3 nmol 2.2+/-0.4 g vs saline, P<0.01; 2 hour food intake: orexin-B 3 nmol, 2.4+/-0.3 g vs saline, 1.3+/-0.2 g, P<0.05). Following ICV orexin-A, hypothalamic c-fos, a maker of neuronal activation, was highly expressed in the paraventricular nucleus (PVN), and the arcuate nucleus (P<0.005 for both). IntraPVN injection of orexin-A stimulated 2 h food intake by one gram (orexin-A 0.03 nmol, 1.6+/-0. 3 g vs saline, 0.5+/-0.3 g, P<0.005). These findings support the suggestion that the orexins stimulate food intake. However, this effect is weak and may cast doubt upon their physiological importance in appetite regulation in the rat. (+info)

Topical all-trans retinoic acid augments ultraviolet radiation-induced increases in activated melanocyte numbers in mice. (4/1585)

We have previously shown that daily application of 0.05% retinoic acid to the backs of lightly pigmented, hairless HRA:Skh-2 mice increases melanogenesis resulting from exposure to solar-simulated ultraviolet radiation. In this study we show that as early as 1 wk following commencement of treatment, there is a 2- fold increase in the number of epidermal 3,4-dihydroxyphenylalanine positive melanocytes in retinoic acid and ultraviolet radiation treated HRA:Skh-2 mice compared with mice that received ultraviolet radiation only. This increased to a 2.9-fold difference by 6 wk. Retinoic acid also augmented ultraviolet radiation-stimulated melanogenesis, with a 4-fold increase being observed after only 2 wk. These findings were also seen in C57BL mice. Ultraviolet radiation and retinoic acid needed to be applied to the same skin site for the augmentation in melanocyte activation to occur. Ultraviolet B rather than ultraviolet A was mainly responsible for melanogenesis and the retinoic acid primarily increased ultraviolet B-induced melanogenesis. Furthermore, retinoic acid on it's own, in the absence of ultraviolet radiation caused a small but statistically significant increase in 3,4-dihydroxyphenylalanine positive melanocyte numbers and melanogenesis. Thus topical retinoic acid is a potent modulator of melanocyte activation. Alone it is able to increase the number of activated epidermal melanocytes and make melanocytes more sensitive to activation by ultraviolet B. (+info)

Tumor necrosis factor alpha-mediated inhibition of melanogenesis is dependent on nuclear factor kappa B activation. (5/1585)

Melanogenesis is a physiological process resulting in the synthesis of melanin pigments which play a crucial protective role against skin photocarcinogenesis. In vivo, solar ultraviolet light triggers the secretion of numerous keratinocyte-derived factors that are implicated in the regulation of melanogenesis. Among these, tumor necrosis factor alpha (TNFalpha), a cytokine implicated in the pro-inflammatory response, down-regulates pigment synthesis in vitro. In this report, we aimed to determine the molecular mechanisms by which this cytokine inhibits melanogenesis in B16 melanoma cells. First, we show that TNFalpha inhibits the activity and protein expression of tyrosinase which is the key enzyme of melanogenesis. Further, we demonstrate that this effect is subsequent to a down-regulation of the tyrosinase promoter activity in both basal and cAMP-induced melanogenesis. Finally, we present evidence indicating that the inhibitory effect of TNFalpha on melanogenesis is dependent on nuclear factor kappa B (NFkappaB) activation. Indeed, overexpression of this transcription factor in B16 cells is sufficient to inhibit tyrosinase promoter activity. Furthermore, a mutant of inhibitory kappa B (IkappaB), that prevents NFkappaB activation, is able to revert the effect of TNFalpha on the tyrosinase promoter activity. Taken together, our results clarify the mechanisms by which TNFalpha inhibits pigmentation and point out the key role of NFkappaB in the regulation of melanogenesis. (+info)

Purification and characterization of a secreted laccase of Gaeumannomyces graminis var. tritici. (6/1585)

We purified a secreted fungal laccase from filtrates of Gaeumannomyces graminis var. tritici cultures induced with copper and xylidine. The active protein had an apparent molecular mass of 190 kDa and yielded subunits with molecular masses of 60 kDa when denatured and deglycosylated. This laccase had a pI of 5.6 and an optimal pH of 4.5 with 2,6-dimethoxyphenol as its substrate. Like other, previously purified laccases, this one contained several copper atoms in each subunit, as determined by inductively coupled plasma spectroscopy. The active enzyme catalyzed the oxidation of 2, 6-dimethoxyphenol (Km = 2.6 x 10(-5) +/- 7 x 10(-6) M), catechol (Km = 2.5 x 10(-4) +/- 1 x 10(-5) M), pyrogallol (Km = 3.1 x 10(-4) +/- 4 x 10(-5) M), and guaiacol (Km = 5.1 x 10(-4) +/- 2 x 10(-5) M). In addition, the laccase catalyzed the polymerization of 1, 8-dihydroxynaphthalene, a natural fungal melanin precursor, into a high-molecular-weight melanin and catalyzed the oxidation, or decolorization, of the dye poly B-411, a lignin-like polymer. These findings indicate that this laccase may be involved in melanin polymerization in this phytopathogen's hyphae and/or in lignin depolymerization in its infected plant host. (+info)

Possible involvement of proteolytic degradation of tyrosinase in the regulatory effect of fatty acids on melanogenesis. (7/1585)

The purpose of this study was to investigate the mechanism of fatty acid-induced regulation of melanogenesis. An apparent regulatory effect on melanogenesis was observed when cultured B16F10 melanoma cells were incubated with fatty acids, i.e., linoleic acid (unsaturated, C18:2) decreased melanin synthesis while palmitic acid (saturated, C16:0) increased it. However, mRNA levels of the melanogenic enzymes, tyrosinase, tyrosinase-related protein 1 (TRP1), and tyrosinase-related protein 2 (TRP2), were not altered. Regarding protein levels of these enzymes, the amount of tyrosinase was decreased by linoleic acid and increased by palmitic acid, whereas the amounts of TRP1 and TRP2 did not change after incubation with fatty acids. Pulse-chase assay by [35S]methionine metabolic labeling revealed that neither linoleic acid nor palmitic acid altered the synthesis of tyrosinase. Further, it was shown that linoleic acid accelerated, while palmitic acid decelerated, the proteolytic degradation of tyrosinase. These results suggest that modification of proteolytic degradation of tyrosinase is involved in regulatory effects of fatty acids on melanogenesis in cultured melanoma cells. (+info)

Structure and developmental expression of the ascidian TRP gene: insights into the evolution of pigment cell-specific gene expression. (8/1585)

The tyrosinase family in vertebrates consists of three related melanogenic enzymes: tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2. These proteins control melanin production in pigment cells and play a crucial role in determining vertebrate coloration. We have isolated a gene from the ascidian Halocynthia roretzi which encodes a tyrosinase-related protein (HrTRP) with 45-49% identity with vertebrate TRP-1 and TRP-2. The expression of the HrTRP gene in pigment lineage a8.25 cells starts at the early-mid gastrula stage, which coincides with the stage when these cells are determined as pigment precursor cells; therefore, it provides the earliest pigment lineage-specific marker, which enables us to trace the complete cell lineage leading to two pigment cells in the larval brain. In addition, the expression pattern of the HrTRP gene appears to share similar characteristics with the mouse TRP-2 gene although structurally the HrTRP gene is more closely related to mammalian TRP-1 genes. Based on these observations and on results from molecular phylogenetic and hybridization analyses, we suggest that triplication of the tyrosinase family occurred during the early radiation of chordates. Initially, duplication of an ancestral tyrosinase gene produced a single TRP gene before the urochordate and cephalochordate-vertebrate divergence, and a subsequent duplication of the ancestral TRP gene in the vertebrate lineage gave rise to two TRP genes before the emergence of teleost fishes. Evolution of the melanin synthetic pathway and possible phylogenetic relationships among chordate pigment cells that accommodate the metabolic process are discussed. Dev Dyn 1999;215:225-237. (+info)

Melanin[edit]. Melanin is a chromophore that exists in the human epidermal layer of skin responsible for protection from ... When melanocytes are stimulated by solar radiation, melanin is produced.[7] Melanin is one of the major absorbers of light in ... Other tissue components with less significant contributions to the total absorption spectrum of tissue are melanin and fat. ... Extinction coefficient of melanin by Steven Jacques. URL: http://omlc.ogi.edu/spectra/melanin/extcoeff.html. ...

https://en.wikipedia.org/wiki/Near-infrared_window_in_biological_tissue

... containing increased melanin, the pigment responsible for skin color) and hypomelanotic (containing decreased melanin).[3] ... Increased melanin[edit]. Acquired[edit]. *Acquired melanocytic nevus *Types of acquired melanocytic nevi are categorized based ...

https://en.wikipedia.org/wiki/Mole_(skin_marking)

Melanin[edit]. The amount of the brown pigment melanin in the skin increases after exposure to UV radiation at moderate levels ... UVA gives a quick tan that lasts for days by oxidizing melanin that was already present and triggers the release of the melanin ... The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, blocking the UV from damaging skin ... Melanin is an excellent photoprotectant that absorbs both UVB and UVA radiation and dissipates the energy as harmless heat, ...

https://en.wikipedia.org/wiki/UV

... although the single most important substance determining human skin color is the pigment melanin. Melanin is produced within ... Melanoid: It resembles melanin but is present diffusely throughout the epidermis.. *Carotene: This pigment is yellow to orange ... Melanin: It is brown in color and present in the basal layer of the epidermis. ... Skin has mesodermal cells, pigmentation, such as melanin provided by melanocytes, which absorb some of the potentially ...

https://en.wikipedia.org/wiki/Human_skin

Melanin *Increase pheomelanin, reduce eumelanin. *Cancer *Support hormone-sensitive breast cancers (see section below) ...

https://en.wikipedia.org/wiki/Oestrogen

Melanin biosynthesis, which is quite high in C. geophilum, gives its hyphae the "jet-black" appearance, and has been linked ... Fernandez, C. W., & Koide, R. T. (2013). The function of melanin in the ectomycorrhizal fungus Cenococcum geophilum under water ... Butler, M. J., & Day, A. W. (1998). Destruction of fungal melanins by ligninases of Phanerochaete chrysosporium and other white ... Butler, M. J., & Day, A. W. (1998). Fungal melanins: a review. Canadian Journal of Microbiology, 44(12), 1115-1136. ...

https://en.wikipedia.org/wiki/Cenococcum_geophilum

However, this is unlikely since fungal melanin is structurally and biochemically different from human melanin and other species ... The dark colour is due to the presence of the dark pigment melanin. Hyphae are septate, as is the case for species belonging to ... It is hypothesized that predilection of this species for the central nervous system is due to the presence of melanin, which ... ISBN 0-8121-0566-4. Butler, M. J.; Day, A. W. (1998). "Fungal melanins: A review". Canadian Journal of Microbiology. 44 (12): ...

https://en.wikipedia.org/wiki/Cladophialophora_bantiana

Further information: Melanin theory. The term melanism has been used on Usenet, internet forums and blogs to mean an African- ... Melanin is the primary determinant of the degree of skin pigmentation and protects the body from harmful ultraviolet radiation ... The same ultraviolet radiation is essential for the synthesis of vitamin D in skin, so lighter colored skin - less melanin - is ... such as that the melanin pigment enhances function of immune defences,[13] or a thermal advantage from the darker coloration.[ ...

https://en.wikipedia.org/wiki/Melanism

Kirkpatrick, D.S., McGinness, J.E., Moorhead, W.D., Corry, P.M., and Proctor, P.H.: Melanin-Water-Ion Dielectric Interaction. ... The department had an interest in the physical properties of melanin as a possible hook to treating melanoma. While of enormous ... Kono, R. and McGinness, J.E.: Anomalous Absorption and Sound in DBA Melanins. J. Applied Physics, 50(3): 1236-1244, 1979. ... Filatovs, G.J., McGinness, J.E., Williams, L.: Statistical Analysis of Switching Melanins. Physicol. Chem. and Phys. Vol. 12, ...

https://en.wikipedia.org/wiki/John_McGinness

Melanin also protects the fungal cell wall from hydrolysis by scavenging the free radicals and hypochlorite produced by the ... Jacobson, Eric S. (2000). "Pathogenic Roles for Fungal Melanins". Clinical Microbiology Reviews. 13 (4): 708-717. doi:10.1128/ ... mackenziei for brain tissue is unknown but has been hypothesized to involve the fungal melanin which acts as a virulence factor ...

https://en.wikipedia.org/wiki/Rhinocladiella_mackenziei

"The chemistry of the melanins. Part V. The autoxidation of 5 : 6-dihydroxyindoles". Journal of the Chemical Society (Resumed): ... by the tyrosinase type polyphenol oxidase from tyrosine and catecholamines leading to the formation of catechol melanin. Like ...

https://en.wikipedia.org/wiki/Indole-5,6-quinone

The "melanin (polyacetylenes) bistable switch" currently is part of the chips collection of the Smithsonian Institution. In ... John McGinness; Corry, Peter; Proctor, Peter (March 1, 1974). "Amorphous Semiconductor Switching in Melanins". Science. 183 ( ...

https://en.wikipedia.org/wiki/Organic_semiconductor

Chemically they are closely related to dopamine, and there is a type of melanin, known as dopamine-melanin, that can be ... The melanin that darkens human skin is not of this type: it is synthesized by a pathway that uses L-DOPA as a precursor but not ... Dopamine-derived melanin probably appears in at least some other biological systems as well. Some of the dopamine in plants is ... It can be metabolized in a variety of ways, producing melanin and a variety of alkaloids as byproducts. The functions of plant ...

https://en.wikipedia.org/wiki/Dopamine

Generally, if more melanin is present, the color of the hair is darker; if less melanin is present, the hair is lighter. The ... Levels of melanin can vary over time causing a person's hair color to change, and it is possible to have hair follicles of more ... Gray or white hair is not caused by a true gray or white pigment, but is due to a lack of pigmentation and melanin. The clear ... Over 95% of melanin content in black and brown hair is eumelanin. Pheomelanin is generally found in elevated concentrations in ...

https://en.wikipedia.org/wiki/Human_hair_color

CS1 maint: discouraged parameter (link) Daniel, Jo (28 November 2019). "Melanin Popping! Nigerian model Mary Timms slays In ...

https://en.wikipedia.org/wiki/Mary_Timms

MELANIN MAJORITY. February 9, 2017. Retrieved October 13, 2019. Salih, Hassan (November 23, 2016). "What happened at MESH ...

https://en.wikipedia.org/wiki/Fred_Martins

Biosynthesis of melanin occurs in melanocytes, where tyrosine is converted into DOPA and then dopaquinone, which goes on to be ... l-Dopaquinone also known as o-dopaquinone is a metabolite of L-DOPA (L-dihydroxyphenylalanine) and a precursor of melanin. ... Hearing VJ (2011). "Determination of melanin synthetic pathways". J. Invest. Dermatol. 131 (E1): E8-E11. doi:10.1038/skinbio. ... Schlessinger, Daniel I.; Schlessinger, Joel (January 2020). "Biochemistry, Melanin". StatPearls Publishing. PMID 29083759. ...

https://en.wikipedia.org/wiki/L-Dopaquinone