Questions tagged [melanin]
Biopigment, present in the skin and hair of humans.
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Toxicity of phaeomelanin
I have been reading an article discussing a study by Tiffany Slater and Maria McNamara in which they identified molecular evidence of phaeomelanin in the fossil record. Slater is quoted as saying &...
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Intensity of UVA needed to damage skin and cause ageing
Using a UVA/B measuring device, I was able to determine that approximately $\pu{10 μW/cm^2}$ penetrates a window even when not in direct sunlight. For reference, the intensity of direct sunlight ...
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Do any animals mix porphyrins and carotenoids in their pigmentation?
Many animals (particularly birds) use carotenoids or porphyrins in their diet to contribute to the brilliance of their skin/fur/feather coloration. A few even mix melanin in with carotenoids to get ...
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Why does more melanin means harder vitamin D production if melanocytes lie deeper in the skin than keratinocytes?
From my Googling, I understand that keratinocytes are primarily responsible for generating vitamin D from UV rays, and melanocytes are for producing melanin to block UV rays. However in lots of skin ...
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Why are many skin depigmenting agents toxic to the body?
Coming from a developing country, I know many people who regularly use these creams to lighten their skin and some of them have developed liver and kidney problems as a result.
I know that many ...
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Does melanin protect against nuclear radiation?
It is known that melanin protects against UV radiation.
But say a nuclear bomb dropped somewhere would more people of dark complexion survive the radiation burns because the melanin would protect ...
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Why does hair turn white but not skin?
From my understanding melanocyte stem cells (McSCs) stop being produced and we have a finite reserve that gets depleted with time. They're at the origin of melanocytes that create hair and skin ...
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Which chemokines are being produced by melanocytes?
I am looking into Vitiligo it's an autoimmune disease that results in apoptosis of melanocytes due to misfolded protein accumulation.
It also dramatically increases breast cancer rates (600 times) ...
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Does vitamin D affect melanin concentration?
I am aware of the affect on vitamin D production by melanin (in sunlight) but I can not find any information regarding a reverse connection.
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What kind melanin do fair or light skinned black or mixed people have, eumelanin of pheomelanin?
I am doing a study on melanin and conductivity but I cannot find the answer to this question anywhere. Do light complected black or biracial people have eumelanin or pheomelanin? or both?
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What part of the skin is damaged under sun exposure?
How exactly does extensive sun exposure lead to skin damage and increase cancer risk. In which part of the skin is the sun doing the most damage. Is it in the epidermis or beneath ? I would like to ...
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Could being exposed to excess UV in the arctic lead to a human eye color change? If so, what is the mechanism?
The CBS News article Expedition Antarctica: A father and son's journey to save the planet says (in part):
Thirty-two years ago, Robert Swan made history as the first person to walk to both poles. ...
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Why does the scalp hair become grey first?
I understand that when the hair follicles produce less melanin or stop producing melanin altogether, hair becomes grey. But it seems like it is the scalp hair that becomes grey first. If follicles are ...
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Can cysteine alone change pigmentation?
According to this graph (from here):
cysteine contributes to pheomelanogenesis, and having a high enough concentration of cysteine makes the shift towards pheomelanin instead of eumelanin. So my ...
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Why is black eumelanin black even though it consists of black AND brown molecules?
In dogs,eumelanin consists of molecules of DHI and DHICA. DHI and DHICA are made from dopachrome. DHI through DHI oxidase and DHICA through DHICA oxidase also known as TYRP1. When TYRP1 has a mutation ...
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What decides between the synthesis of eumelanin and pheomelanin on a biochemical level?
MC1R is a very well known gene where a loss-of-function mutation will cause the synthesis of pale/redish pheomelanin instead of black/brown eumelanin. MC1R is only a receptor which doesn't directly ...
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How does TYRP1 affect the synthesis of black and brown eumelanin (on a biochemical level)?
TYRP1 (aka B-locus) is a gene in dogs that determines whether black or brown eumelanin is produced (assuming eumelanin is produced at all which is determined by the MC1R gene). I've looked at many ...
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How to increase pheomelanin production?
How can you increase the pheomelanin production in your body, while decreasing the eumelanin production? In other words, shifting the balance towards pheomelanin.
From what I see, sulfur and cysteine ...
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Why is hyper pigmentation the common aftermath of skin lesions and abrasions?
I'm aware that melanocytes produce melanin, giving color to the skin, but why are these cells recruited or overactive when healing skin abrasions, lesions and sores when T-cells and inflammatory ...
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How long does a tan last?
How long do melanocytes and melanosomes continue to protect DNA after UV exposure? Basically, if skin is tanned, then over the next month it is shed, will melanocytes continue to produce high levels ...
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Why Do Most Humans & Cats Have Blue/Bluish Eyes At Birth?
I've read that the eye color at birth for most humans and for cats may not always be the the true genetic color at first. This is due to the lack of melanin in the iris. This makes sense as there is ...
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