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Wakamatsu K, Ito S. Recent Advances in Characterization of Melanin Pigments in Biological Samples. Int J Mol Sci 2023; 24:ijms24098305. [PMID: 37176019 PMCID: PMC10179066 DOI: 10.3390/ijms24098305] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
The melanin pigments eumelanin (EM) and pheomelanin (PM), which are dark brown to black and yellow to reddish-brown, respectively, are widely found among vertebrates. They are produced in melanocytes in the epidermis, hair follicles, the choroid, the iris, the inner ear, and other tissues. The diversity of colors in animals is mainly caused by the quantity and quality of their melanin, such as by the ratios of EM versus PM. We have developed micro-analytical methods to simultaneously measure EM and PM and used these to study the biochemical and genetic fundamentals of pigmentation. The photoreactivity of melanin has become a major focus of research because of the postulated relevance of EM and PM for the risk of UVA-induced melanoma. Our biochemical methods have found application in many clinical studies on genetic conditions associated with alterations in pigmentation. Recently, besides chemical degradative methods, other methods have been developed for the characterization of melanin, and these are also discussed here.
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Affiliation(s)
- Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-192, Aichi, Japan
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-192, Aichi, Japan
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Olsson P, Lind O, Mitkus M, Delhey K, Kelber A. Lens and cornea limit UV vision of birds - a phylogenetic perspective. J Exp Biol 2021; 224:jeb243129. [PMID: 34581400 PMCID: PMC8601714 DOI: 10.1242/jeb.243129] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/21/2021] [Indexed: 12/03/2022]
Abstract
Most vertebrates have UV-sensitive vision, but the UV sensitivity of their eyes is limited by the transmittance of the ocular media, and the specific contribution of the different media (cornea, lens) has remained unclear. Here, we describe the transmittance of all ocular media (OMT), as well as that of lenses and corneas of birds. For 66 species belonging to 18 orders, the wavelength at which 50% of light is transmitted through the ocular media to the retina (λT0.5) ranges from 310 to 398 nm. Low λT0.5 corresponds to more UV light transmitted. Corneal λT0.5 varies only between 300 and 345 nm, whereas lens λT0.5 values are more variable (between 315 and 400 nm) and tend to be the limiting factor, determining OMT in the majority of species. OMT λT0.5 is positively correlated with eye size, but λT0.5 of corneas and lenses are not correlated with their thickness when controlled for phylogeny. Corneal and lens transmittances do not differ between birds with UV- and violet-sensitive SWS1 opsin when controlling for eye size and phylogeny. Phylogenetic relatedness is a strong predictor of OMT, and ancestral state reconstructions suggest that from ancestral intermediate OMT, highly UV-transparent ocular media (low λT0.5) evolved at least five times in our sample of birds. Some birds have evolved in the opposite direction towards a more UV-opaque lens, possibly owing to pigmentation, likely to mitigate UV damage or reduce chromatic aberration.
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Affiliation(s)
- Peter Olsson
- Department of Biology, Lund University, 22362 Lund, Sweden
| | - Olle Lind
- Department of Biology, Lund University, 22362 Lund, Sweden
- Department of Philosophy, Lund University, 22100 Lund, Sweden
| | | | - Kaspar Delhey
- Max Planck Institute for Ornithology, 78315 Seewiesen, Germany
- School of Biological Sciences, Monash University, 3800 Clayton, Victoria, Australia
| | - Almut Kelber
- Department of Biology, Lund University, 22362 Lund, Sweden
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Galván I. Predation risk determines pigmentation phenotype in nuthatches by melanin-related gene expression effects. J Evol Biol 2018; 31:1760-1771. [DOI: 10.1111/jeb.13379] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/19/2018] [Accepted: 09/19/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Ismael Galván
- Department of Evolutionary Ecology; Doñana Biological Station; CSIC; Sevilla Spain
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Coloration reflects skin pterin concentration in a red-tailed lizard. Comp Biochem Physiol B Biochem Mol Biol 2016; 193:17-24. [DOI: 10.1016/j.cbpb.2015.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 12/23/2022]
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Lehmann P, Boratyński Z, Mappes T, Mousseau TA, Møller AP. Fitness costs of increased cataract frequency and cumulative radiation dose in natural mammalian populations from Chernobyl. Sci Rep 2016; 6:19974. [PMID: 26814168 PMCID: PMC4728484 DOI: 10.1038/srep19974] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 12/21/2015] [Indexed: 11/09/2022] Open
Abstract
A cataract is a clouding of the lens that reduces light transmission to the retina, and it decreases the visual acuity of the bearer. The prevalence of cataracts in natural populations of mammals, and their potential ecological significance, is poorly known. Cataracts have been reported to arise from high levels of oxidative stress and a major cause of oxidative stress is ionizing radiation. We investigated whether elevated frequencies of cataracts are found in eyes of bank voles Myodes glareolus collected from natural populations in areas with varying levels of background radiation in Chernobyl. We found high frequencies of cataracts in voles collected from different areas in Chernobyl. The frequency of cataracts was positively correlated with age, and in females also with the accumulated radiation dose. Furthermore, the number of offspring in female voles was negatively correlated with cataract severity. The results suggest that cataracts primarily develop as a function of ionizing background radiation, most likely as a plastic response to high levels of oxidative stress. It is therefore possible that the elevated levels of background radiation in Chernobyl affect the ecology and fitness of local mammals both directly through, for instance, reduced fertility and indirectly, through increased cataractogenesis.
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Affiliation(s)
- Philipp Lehmann
- Centre of Excellence in Biological Interactions Research, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.,Department of Zoology, SE-106 91 University of Stockholm, Sweden
| | - Zbyszek Boratyński
- CIBIO/InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, 4485-661 Vairão, Portugal
| | - Tapio Mappes
- Centre of Excellence in Biological Interactions Research, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
| | - Timothy A Mousseau
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Anders P Møller
- Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Bâtiment 362, F-91405 Orsay Cedex, France
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Galván I, Wakamatsu K. Color measurement of the animal integument predicts the content of specific melanin forms. RSC Adv 2016. [DOI: 10.1039/c6ra17463a] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The slope of the reflectance spectra of feathers and hairs predicts their content of 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-eumelanin and benzothiazole-pheomelanin.
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Affiliation(s)
- Ismael Galván
- Department of Evolutionary Ecology
- Doñana Biological Station – CSIC
- 41092 Sevilla
- Spain
| | - Kazumasa Wakamatsu
- Department of Chemistry
- Fujita Health University School of Health Sciences
- Toyoake
- Japan
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Affiliation(s)
- M. B. Blanco
- Duke Lemur Center; Durham NC USA
- Department of Animal Ecology and Conservation; University of Hamburg; Hamburg Germany
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Galván I, Wakamatsu K, Camarero PR, Mateo R, Alonso-Alvarez C. Low-quality birds do not display high-quality signals: The cysteine-pheomelanin mechanism of honesty. Evolution 2014; 69:26-38. [PMID: 25330349 PMCID: PMC4312981 DOI: 10.1111/evo.12549] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 10/06/2014] [Indexed: 01/18/2023]
Abstract
The mechanisms that make that the costs of producing high-quality signals are unaffordable to low-quality signalers are a current issue in animal communication. The size of the melanin-based bib of male house sparrows Passer domesticus honestly signals quality. We induced the development of new bibs while treating males with buthionine-sulfoximine (BSO), a substance that depletes the levels of the antioxidant glutathione (GSH) and the amino acid cysteine, two elements that switch melanogenesis from eumelanin to pheomelanin. Final bib size is negatively related to pheomelanin levels in the bib feathers. BSO reduced cysteine and GSH levels in all birds, but improved phenotypes (bibs larger than controls) were only expressed by high-quality birds (BSO birds with largest bibs initially). Negative associations between final bib size and cysteine levels in erythrocytes, and between pheomelanin and cysteine levels, were observed in high-quality birds only. These findings suggest that a mechanism uncoupling pheomelanin and cysteine levels may have evolved in low-quality birds to avoid producing bibs of size not corresponding to their quality and greater relative costs. Indeed, greater oxidative stress in cells was not observed in low-quality birds. This may represent the first mechanism maintaining signal honesty without producing greater relative costs on low-quality signalers.
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Affiliation(s)
- Ismael Galván
- Departamento de Ecología Evolutiva, Estación Biológica de Doñana - CSIC, c/ Américo Vespucio s/n, 41092, Sevilla, Spain.
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Increased radiation from Chernobyl decreases the expression of red colouration in natural populations of bank voles (Myodes glareolus). Sci Rep 2014; 4:7141. [PMID: 25413373 PMCID: PMC5382704 DOI: 10.1038/srep07141] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 10/17/2014] [Indexed: 01/03/2023] Open
Abstract
Pheomelanin is a pink to red version of melanin pigment deposited in skin and hair. Due to its bright colour, pheomelanin plays a crucial function in signalling, in particular sexual signalling. However, production of pheomelanin, as opposed to its dark alternative, eumelanin, bears costs in terms of consumption of antioxidants important for protection of DNA against naturally produced reactive oxidative species. Therefore, decreased expression of pheomelanin is expected in organisms exposed to severe oxidative stress such as that caused by exposure to chronic ionizing radiation. We tested if variable exposure to radiation among natural populations of bank voles Myodes glareolus in Chernobyl affected expression of red colouration in their dorsal fur. The relative redness of dorsal fur was positively correlated with weight, but also negatively correlated with the level of background radiation. These results suggest that the development of the natural red colouration in adult bank voles is affected by ionizing background radiation, and potentially causing elevated levels of oxidative stress. Reduced production of pheomelanin allows more antioxidants to mitigate the oxidative stress caused by radiation. However, changing natural animal colouration for physiological reasons can have ecological costs, if e.g. it causes mismatch with habitat colouration and conspicuousness for predators.
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Napolitano A, Panzella L, Monfrecola G, d'Ischia M. Pheomelanin-induced oxidative stress: bright and dark chemistry bridging red hair phenotype and melanoma. Pigment Cell Melanoma Res 2014; 27:721-33. [PMID: 24814217 DOI: 10.1111/pcmr.12262] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/08/2014] [Indexed: 01/20/2023]
Abstract
The complex interplay of genetic and epigenetic factors linking sun exposure to melanoma in the red hair phenotype hinges on the peculiar physical and chemical properties of pheomelanins and the underlying biosynthetic pathway, which is switched on by the effects of inactivating polymorphisms in the melanocortin 1 receptor gene. In addition to the long recognized UV-dependent pathways of toxicity and cell damage, a UV-independent pro-oxidant state induced by pheomelanin within the genetically determined background of the red hair phenotype has recently been disclosed. This review provides a detailed discussion of the possible UV-dependent and UV-independent chemical mechanisms underlying pheomelanin-mediated oxidative stress, with special reference to the oxygen-dependent depletion of glutathione and other cell antioxidants. The new concept of pheomelanin as a 'living' polymer and biocatalyst that may grow by exposure to monomer building blocks and may trigger autooxidative processes is also discussed. As a corollary, treatment of inflammatory skin diseases in RHP patients is briefly commented. Finally, possible concerted strategies for melanoma prevention in the red hair phenotype are proposed.
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Galván I, Bonisoli-Alquati A, Jenkinson S, Ghanem G, Wakamatsu K, Mousseau TA, Møller AP. Chronic exposure to low-dose radiation at Chernobyl favours adaptation to oxidative stress in birds. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12283] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Ismael Galván
- Laboratoire d'Ecologie, Systématique et Evolution; CNRS UMR 8079; Université Paris-Sud 11; Bâtiment 362 91405 Orsay Cedex France
| | | | - Shanna Jenkinson
- Department of Biological Sciences; University of South Carolina; Columbia SC 29208 USA
| | - Ghanem Ghanem
- Laboratoire d'Oncologie et de Chirurgie Expérimentale (L.O.C.E.); Institut Jules Bordet; Université Libre de Bruxelles; rue Héger-Bordet 1 1000 Bruxelles Belgium
| | - Kazumasa Wakamatsu
- Department of Chemistry; Fujita Health University School of Health Sciences; Toyoake Aichi 470-1192 Japan
| | - Timothy A. Mousseau
- Department of Biological Sciences; University of South Carolina; Columbia SC 29208 USA
| | - Anders P. Møller
- Laboratoire d'Ecologie, Systématique et Evolution; CNRS UMR 8079; Université Paris-Sud 11; Bâtiment 362 91405 Orsay Cedex France
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Mousseau TA, Møller AP. Elevated frequency of cataracts in birds from chernobyl. PLoS One 2013; 8:e66939. [PMID: 23935827 PMCID: PMC3728354 DOI: 10.1371/journal.pone.0066939] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/11/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Radiation cataracts develop as a consequence of the effects of ionizing radiation on the development of the lens of the eye with an opaque lens reducing or eliminating the ability to see. Therefore, we would expect cataracts to be associated with reduced fitness in free-living animals. METHODOLOGY/PRINCIPAL FINDINGS We investigated the incidence of lens opacities typical of cataracts in more than 1100 free-living birds in the Chernobyl region in relation to background radiation. The incidence of cataracts increased with level of background radiation both in analyses based on a dichotomous score and in analyses of continuous scores of intensity of cataracts. The odds ratio per unit change in the regressor was 0.722 (95% CI 0.648, 0.804), which was less than odds ratios from investigations of radiation cataracts in humans. The relatively small odds ratio may be due to increased mortality in birds with cataracts. We found a stronger negative relationship between bird abundance and background radiation when the frequency of cataracts was higher, but also a direct effect of radiation on abundance, suggesting that radiation indirectly affects abundance negatively through an increase in the frequency of cataracts in bird populations, but also through direct effects of radiation on other diseases, food abundance and interactions with other species. There was no increase in incidence of cataracts with increasing age, suggesting that yearlings and older individuals were similarly affected as is typical of radiation cataract. CONCLUSIONS/SIGNIFICANCE These findings suggest that cataracts are an under-estimated cause of morbidity in free-living birds and, by inference, other vertebrates in areas contaminated with radioactive materials.
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Affiliation(s)
- Timothy Alexander Mousseau
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Anders Pape Møller
- Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Orsay, France
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Galván I, Møller AP. Pheomelanin-Based Plumage Coloration Predicts Survival Rates in Birds. Physiol Biochem Zool 2013; 86:184-92. [DOI: 10.1086/668871] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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