Neuromelanin (NM) is a insoluble polymer pigment produced in specific populations of catecholaminergic neurons in the brain. Humans have the largest amount of NM, which is present in lesser amounts in other primates, and totally absent in many other species. [15] The biological function remains unknown, although human NM has been shown to efficiently bind transition metals such as iron, as well as other potentially toxic molecules. Therefore, it may play crucial roles in apoptosis and the related Parkinson's disease. [16] Other organisms [ edit ] Sarangarajan R, Apte SP (2005). "Melanin aggregation and polymerization: possible implications in age-related macular degeneration". Ophthalmic Research. 37 (3): 136–41. doi: 10.1159/000085533. PMID 15867475. S2CID 27499198. Liu Y, Hong L, Kempf VR, Wakamatsu K, Ito S, Simon JD (June 2004). "Ion-exchange and adsorption of Fe(III) by Sepia melanin". Pigment Cell Research. 17 (3): 262–9. doi: 10.1111/j.1600-0749.2004.00140.x. PMID 15140071. Nappi, A. J. & Christensen, B. M. Melanogenesis and associated cytotoxic reactions: applications to insect innate immunity. Insect Biochem. Mol. Biol. 35, 443–459 (2005). Pheomelanin. This type of melanin pigments your lips, nipples and other pinkish parts of your body. People who have equal parts eumelanin and pheomelanin have red hair.

Thody, A. J.; Higgins, E. M.; Wakamatsu, K.; Ito, S.; Burchill, S. A.; Marks, J. M. (August 1991). "Pheomelanin as well as eumelanin is present in human epidermis". The Journal of Investigative Dermatology. 97 (2): 340–344. doi: 10.1111/1523-1747.ep12480680. PMID 2071942. Following the hemocyte washes, 1 ml of cell-free hemolymph was added to the entirety of the MatTek dish, followed by an addition 1 ml of IPS. The MatTek dish was covered and imaged using the OpenFlexure microscope and software and time-lapse microscopy was performed every minute for 16–24 h 63. Control experiments without added fungus or fungal components, or with anticoagulation buffer to inhibit melanization and coagulation, were performed (Supplementary Movies 11 and 12). This protocol is summarized in Supplementary Fig. 3b. Wade, Nicholas (19 August 2003). "Why Humans and Their Fur Parted Ways". The New York Times. ISSN 0362-4331 . Retrieved 24 August 2019. Yao, Zeng-Yu; Qi, Jian-Hua (22 April 2016). "Comparison of Antioxidant Activities of Melanin Fractions from Chestnut Shell". Molecules. 21 (4): 487. doi: 10.3390/molecules21040487. PMC 6273334. PMID 27110763. When you spend time out in the sun, your body produces more melanin. The substance absorbs light from UV rays and redistributes it toward the upper layers of skin. It also protects the genetic material stored in your cells by keeping out harmful UV rays.Kavanagh, K. & Fallon, J. P. Galleria mellonella larvae as models for studying fungal virulence. Fungal Biol. Rev. 24, 79–83 (2010). The darker feathers of birds owe their color to melanin and are less readily degraded by bacteria than unpigmented ones or those containing carotenoid pigments. [25] Feathers that contain melanin are also 39% more resistant to abrasion than those that do not because melanin granules help fill the space between the keratin strands that form feathers. [26] [27] Pheomelanin synthesis in birds implies the consumption of cysteine, a semi‐essential amino acid that is necessary for the synthesis of the antioxidant glutathione (GSH) but that may be toxic if in excess in the diet. Indeed, many carnivorous birds, which have a high protein content in their diet, exhibit pheomelanin‐based coloration. [28] Hearing loss. Because melanin is found in the stria vascularis of your inner ear, it’s been linked to hearing loss. People who have too little melanin have a higher risk for hearing problems. Smith, D. F. Q. & Casadevall, A. in Fungal Physiology and Immunopathogenesis (ed. Rodrigues, M. L.) 1–30 (Springer International Publishing, 2019).

Cichorek, Mirosława; Wachulska, Małgorzata; Stasiewicz, Aneta; Tymińska, Agata (20 February 2013). "Skin melanocytes: biology and development". Advances in Dermatology and Allergology. 30 (1): 30–41. doi: 10.5114/pdia.2013.33376. PMC 3834696. PMID 24278043. It is now understood that melanins do not have a single structure or stoichiometry. Nonetheless, chemical databases such as PubChem include structural and empirical formulae; typically 3,8-Dimethyl-2,7-dihydrobenzo[1,2,3-cd :4,5,6-c ′d ′]diindole-4,5,9,10-tetrone. This can be thought of as a single monomer that accounts for the measured elemental composition and some properties of melanin, but is unlikely to be found in nature. [47] Solano [47] claims that this misleading trend stems from a report of an empirical formula in 1948, [48] but provides no other historical detail.

Discussion

Mouchet SR, Cortesi F, Bokic B, Lazovic V, Vukusic P, Marshall NJ, Kolaric B (November 2023). "Morphological and Optical Modification of Melanosomes in Fish Integuments upon Oxidation". Optics. 4 (4): 563–562. doi: 10.3390/opt4040041. {{ cite journal}}: CS1 maint: date and year ( link) Harding RM, Healy E, Ray AJ, etal. (April 2000). "Evidence for variable selective pressures at MC1R". American Journal of Human Genetics. 66 (4): 1351–61. doi: 10.1086/302863. PMC 1288200. PMID 10733465. Ignasiak, K. & Maxwell, A. Galleria mellonella (greater wax moth) larvae as a model for antibiotic susceptibility testing and acute toxicity trials. BMC Res. Notes 10, 428 (2017). Solano, F. (2014). "Melanins: Skin Pigments and Much More—Types, Structural Models, Biological Functions, and Formation Routes". New Journal of Science. 2014: 1–28. doi: 10.1155/2014/498276.