Medical research

Mouse and human skin cells produce melanin on a 48-hour cycle

Researchers have discovered that mouse skin and skin cells from humans produce pigmentation in response to sunlight on a 48-hour cycle. They observed that exposing skin to ultraviolet light every 2 days yielded darker pigmentation ...

Medical research

Sunlight continues to damage skin in the dark

Much of the damage that ultraviolet radiation (UV) does to skin occurs hours after sun exposure, a team of Yale-led researchers concluded in a study that was published online Feb. 19 by the journal Science.

Psychology & Psychiatry

Is this peptide a key to happiness?

(Medical Xpress)—What makes us happy? Family? Money? Love? How about a peptide? The neurochemical changes underlying human emotions and social behavior are largely unknown. Now though, for the first time in humans, scientists ...

Genetics

New research unlocks a mystery of albinism

Newly published research provides the first demonstration of how a genetic mutation associated with a common form of albinism leads to the lack of melanin pigments that characterizes the condition.

Medical research

Study finds linchpin of skin response to UVA light

Last year, a team of researchers at Brown University discovered that certain skin cells use a light-sensitive receptor found outside of the eye to sense ultraviolet light and quickly begin pumping out melanin to protect against ...

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Melanin

Melanin i/ˈmɛlənɪn/ (Greek: μέλας, black) is a pigment that is ubiquitous in nature, being found in most organisms (spiders are one of the few groups in which it has not been detected). In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms. All melanins can be considered as derivatives of polyacetylene, since they rely on a polyconiugate structure. Another common form of melanin is pheomelanin, a red-brown polymer of benzothiazine units largely responsible for red hair and freckles. The presence of melanin in the archaea and bacteria kingdoms is an issue of ongoing debate among researchers in the field.

The increased production of melanin in human skin is called melanogenesis. Production of melanin is stimulated by DNA damage induced by UVB-radiation, and it leads to a delayed development of a tan. This melanogenesis-based tan takes more time to develop, but it is long-lasting.

The photochemical properties of melanin make it an excellent photoprotectant. It absorbs harmful UV-radiation (ultraviolet) and transforms the energy into harmless heat through a process called "ultrafast internal conversion". This property enables melanin to dissipate more than 99.9% of the absorbed UV radiation as heat (see photoprotection). This prevents the indirect DNA damage that is responsible for the formation of malignant melanoma and other skin cancers.

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