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Pheomelanin

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https://www.readbyqxmd.com/read/29160957/insect-cuticular-melanins-are-distinctly-different-from-those-of-mammalian-epidermal-melanins
#1
Hanine Barek, Manickam Sugumaran, Shosuke Ito, Kazumasa Wakamatsu
Melanin from several insect samples were isolated and subjected to chemical degradation and HPLC analysis for melanin markers. Quantification of different melanin markers reveals that insect melanins are significantly different from that of the mammalian epidermal melanins. The eumelanin produced in mammals are derived from the oxidative polymerization of both 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid. The pheomelanin is formed by the oxidative polymerization of cysteinyldopa. Thus dopa is the major precursor for both eumelanin and pheomelanin in mammals...
November 21, 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/29124695/photodermatoses-in-the-pigmented-skin
#2
Vinod Kumar Sharma, Kanika Sahni
Skin colour (specifically in relation to its melanin content and composition) has a marked influence on its interaction with ultraviolet light. Eumelanin has mainly photoprotective properties while pheomelanin has the ability to cause formation of reactive oxygen species. This difference is responsible for the difference in incidence and presentation of various idiopathic photodermatoses in dark skinned patients compared to those with lighter skin types. Certain conditions are peculiar to darker skins including pin point popular variant of polymorphous light eruption...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/29054114/characterization-of-melanosomes-and-melanin-in-japanese-patients-with-hermansky-pudlak-syndrome-types-1-4-6-and-9
#3
Ken Okamura, Yuko Abe, Yuta Araki, Kazumasa Wakamatsu, Mariko Seishima, Takafumi Umetsu, Atsushi Kato, Masakazu Kawaguchi, Masahiro Hayashi, Yutaka Hozumi, Tamio Suzuki
Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism (OCA), a bleeding tendency and ceroid deposition. Most of the causative genes for HPS encode subunits of the biogenesis of lysosome-related organelles complex (BLOC). In this study, we identified one patient each with HPS4, HPS6 and HPS9 by whole-exome sequencing. Next, we analyzed hair samples from the three patients and representative patients with HPS1 and controls using electron microscopy and chemical methods...
October 20, 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/28878021/ck1%C3%AE-ablation-in-keratinocytes-induces-p53-dependent-sunburn-protective-skin-hyperpigmentation
#4
Chung-Hsing Chang, Che-Jung Kuo, Takamichi Ito, Yu-Ya Su, Si-Tse Jiang, Min-Hsi Chiu, Yi-Hsiung Lin, Andrea Nist, Marco Mernberger, Thorsten Stiewe, Shosuke Ito, Kazumasa Wakamatsu, Yi-An Hsueh, Sheau-Yann Shieh, Irit Snir-Alkalay, Yinon Ben-Neriah
Casein kinase 1α (CK1α), a component of the β-catenin destruction complex, is a critical regulator of Wnt signaling; its ablation induces both Wnt and p53 activation. To characterize the role of CK1α (encoded by Csnk1a1) in skin physiology, we crossed mice harboring floxed Csnk1a1 with mice expressing K14-Cre-ER(T2) to generate mice in which tamoxifen induces the deletion of Csnk1a1 exclusively in keratinocytes [single-knockout (SKO) mice]. As expected, CK1α loss was accompanied by β-catenin and p53 stabilization, with the preferential induction of p53 target genes, but phenotypically most striking was hyperpigmentation of the skin, importantly without tumorigenesis, for at least 9 mo after Csnk1a1 ablation...
September 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28873228/photodegradation-of-eumelanin-and-pheomelanin-and-its-pathophysiological-implications
#5
REVIEW
Shosuke Ito, Kazumasa Wakamatsu, Tadeusz Sarna
Eumelanin is photoprotective for pigmented tissues while pheomelanin is phototoxic. In this review, we summarize current understanding of how eumelanin and pheomelanin structures are modified by ultraviolet A (UVA) and also by visible light and how reactive oxygen species participate in those processes. Alkaline hydrogen peroxide oxidation was employed to characterize eumelanin and benzothiazole-type pheomelanin, giving pyrrole-2,3,5-tricarboxylic acid (PTCA) and thiazole-2,4,5-tricarboxylic acid (TTCA), respectively...
September 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28831177/condition-dependence-of-pheomelanin-based-coloration-in-nuthatches-sitta-europaea-suggests-a-detoxifying-function-implications-for-the-evolution-of-juvenile-plumage-patterns
#6
Ismael Galván
Adult-like juvenile plumage patterns often signal genotypic quality to parents. During adulthood, the same patterns often signal quality to mates. This has led to assume that adult-like juvenile plumage is a developmental consequence of sexual selection operating in adults. Many of these patterns are produced by the pigment pheomelanin, whose synthesis may help remove toxic excess cysteine. Excess cysteine is likely to arise under conditions of relatively low stress, such as those experienced by nestling birds...
August 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28805337/genetic-favouring-of-pheomelanin-based-pigmentation-limits-physiological-benefits-of-coloniality-in-lesser-kestrels-falco-naumanni
#7
Ismael Galván, Virginia Moraleda, Ignacio Otero, Ernesto Álvarez, Ângela Inácio
Pheomelanin contributes to the pigmentation phenotype of animals by producing orange and light brown colours in the integument. However, pheomelanin synthesis in melanocytes requires consumption of glutathione (GSH), the most important intracellular antioxidant. Therefore, a genetic control favouring the production of large amounts of pheomelanin for pigmentation may lead to physiological costs under environmental conditions that promote oxidative stress. We investigated this possibility in the context of breeding coloniality, a reproductive strategy that may affect oxidative stress...
October 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28753659/melanic-variation-underlies-aposematic-color-variation-in-two-hymenopteran-mimicry-systems
#8
Heather M Hines, Paige Witkowski, Joseph S Wilson, Kazumasa Wakamatsu
The stinging hymenopteran velvet ants (Mutillidae) and bumble bees (Apidae: Bombus spp.) have both undergone extensive diversification in aposematic color patterns, including yellow-red hues and contrasting dark-light body coloration, as a result of Müllerian mimicry. Understanding the genetic and developmental mechanisms underlying shifts in these mimetic colors requires characterization of their pigmentation. In this study, a combination of solubility, spectrophotometry, and melanin degradation analysis are applied to several color forms and species of these lineages to determine that orange-red colors in both lineages are comprised of primarily dopamine-derived pheomelanins...
2017: PloS One
https://www.readbyqxmd.com/read/28730346/gyrfalcons-falco-rusticolus-adjust-ctns-expression-to-food-abundance-a-possible-contribution-to-cysteine-homeostasis
#9
Ismael Galván, Ângela Inácio, Ólafur K Nielsen
Melanins form the basis of animal pigmentation. When the sulphurated form of melanin, termed pheomelanin, is synthesized, the sulfhydryl group of cysteine is incorporated to the pigment structure. This may constrain physiological performance because it consumes the most important intracellular antioxidant (i.e., glutathione, GSH), of which cysteine is a constitutive amino acid. However, this may also help avoid excess cysteine, which is toxic. Pheomelanin synthesis is regulated by several genes, some of them exerting this regulation by controlling the transport of cysteine in melanocytes...
July 20, 2017: Oecologia
https://www.readbyqxmd.com/read/28726920/pheomelanin-molecular-vibration-is-associated-with-mitochondrial-ros-production-in-melanocytes-and-systemic-oxidative-stress-and-damage
#10
Ismael Galván, Alberto Jorge, María García-Gil
Vibrations in covalent bonds affect electron delocalization within molecules, as reported in polymers. If synthesized by living cells, the electron delocalization of polymers affects the stabilization of cellular free radicals, but biomolecular vibration has never been considered a potential source of cytotoxicity. Here we show that the vibrational characteristics of natural pheomelanin and eumelanin contribute to feather color expression in four poultry breeds with different melanin-based pigmentation patterns, but only the vibrational characteristics of pheomelanin are related to the production of reactive oxygen species (ROS) in the mitochondria of melanocytes and to systemic levels of cellular oxidative stress and damage...
September 18, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28639704/genome-wide-association-analysis-identifies-potential-regulatory-genes-for-eumelanin-pigmentation-in-chicken-plumage
#11
L Yang, X Du, S Wei, L Gu, N Li, Y Gong, S Li
Plumage color in chicken is determined by the proportion of eumelanin and pheomelanin pigmentation. As the main ingredient in plumage melanin, eumelanin plays a key role in the dark black, brown and grey coloration. However, very few studies have been performed to identify the related genes and mutations on a genome-wide scale. Herein, a resource family consisting of one backcross population and two F2 cross populations between a black roster and Yukou Brown I parent stockbreed was constructed for identification of genes related to eumelanin pigmentation...
October 2017: Animal Genetics
https://www.readbyqxmd.com/read/28560094/eumelanin-and-pheomelanin-are-predominant-pigments-in-bumblebee-apidae-bombus-pubescence
#12
Carlo Polidori, Alberto Jorge, Concepción Ornosa
BACKGROUND: Bumblebees (Hymenoptera: Apidae: Bombus) are well known for their important inter- and intra-specific variation in hair (or pubescence) color patterns, but the chemical nature of the pigments associated with these patterns is not fully understood. For example, though melanization is believed to provide darker colors, it still unknown which types of melanin are responsible for each color, and no conclusive data are available for the lighter colors, including white. METHODS: By using dispersive Raman spectroscopy analysis on 12 species/subspecies of bumblebees from seven subgenera, we tested the hypothesis that eumelanin and pheomelanin, the two main melanin types occurring in animals, are largely responsible for bumblebee pubescence coloration...
2017: PeerJ
https://www.readbyqxmd.com/read/28546507/individual-quality-as-sensitivity-to-cysteine-availability-in-a-melanin-based-honest-signalling-system
#13
Ismael Galván, Carlos Alonso-Alvarez
The evolution of honest animal communication is mostly understood through the handicap principle, which is intrinsically dependent on the concept of individual quality: low-quality individuals are prevented from producing high-quality signals because if they did so, they would pay greater production costs than high-quality individuals. We tested an alternative explanation for the black bib size of male house sparrows Passer domesticus, an honest signal of quality whose expression is negatively related to levels of the pigment pheomelanin in its contituent feathers...
May 25, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28386436/a-novel-locus-on-chromosome-1-underlies-the-evolution-of-a-melanic-plumage-polymorphism-in-a-wild-songbird
#14
Yann X C Bourgeois, Boris Delahaie, Mathieu Gautier, Emeline Lhuillier, Pierre-Jean G Malé, Joris A M Bertrand, Josselin Cornuault, Kazumasa Wakamatsu, Olivier Bouchez, Claire Mould, Jade Bruxaux, Hélène Holota, Borja Milá, Christophe Thébaud
Understanding the mechanisms responsible for phenotypic diversification within and among species ultimately rests with linking naturally occurring mutations to functionally and ecologically significant traits. Colour polymorphisms are of great interest in this context because discrete colour patterns within a population are often controlled by just a few genes in a common environment. We investigated how and why phenotypic diversity arose and persists in the Zosterops borbonicus white-eye of Reunion (Mascarene archipelago), a colour polymorphic songbird in which all highland populations contain individuals belonging to either a brown or a grey plumage morph...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28378380/re-evaluation-of-insect-melanogenesis-research-views-from-the-dark-side
#15
REVIEW
Miranda M A Whitten, Christopher J Coates
Melanins (eumelanin and pheomelanin) are synthesized in insects for several purposes including cuticle sclerotization and color patterning, clot formation, organogenesis, and innate immunity. Traditional views of insect immunity detail the storage of pro-phenoloxidases inside specialized blood cells (hemocytes) and their release upon recognition of foreign bodies. Activated phenoloxidases convert monophenols into reactive quinones in a two-step enzymatic reaction, and until recently, the mechanism of tyrosine hydroxylation remained a mystery...
July 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/28271633/pheomelanogenesis-is-promoted-at-a-weakly-acidic-ph
#16
Kazumasa Wakamatsu, Ayano Nagao, Miu Watanabe, Kenta Nakao, Shosuke Ito
The diversity of pigmentation in the skin, hair, and eyes of humans has been largely attributed to the diversity of pH in melanosomes with an acidic pH being proposed to suppress melanin production, especially eumelanogenesis. We previously showed that an acidic pH greatly suppresses the late stage of eumelanogenesis after the dopachrome stage. The oxidation of tyrosine by tyrosinase in the presence of cysteine forms cysteinyldopa isomers, which are further oxidized to give rise to pheomelanin via benzothiazine intermediates...
May 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/28240252/novel-quantitative-pigmentation-phenotyping-enhances-genetic-association-epistasis-and-prediction-of-human-eye-colour
#17
Andreas Wollstein, Susan Walsh, Fan Liu, Usha Chakravarthy, Mati Rahu, Johan H Seland, Gisèle Soubrane, Laura Tomazzoli, Fotis Topouzis, Johannes R Vingerling, Jesus Vioque, Stefan Böhringer, Astrid E Fletcher, Manfred Kayser
Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study...
February 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28132436/the-potent-pro-oxidant-activity-of-rhododendrol-eumelanin-induces-cysteine-depletion-in-b16-melanoma-cells
#18
Shosuke Ito, Masae Okura, Kazumasa Wakamatsu, Toshiharu Yamashita
RS-4-(4-Hydroxyphenyl)-2-butanol (rhododendrol, RD), a skin-whitening agent, is known to induce leukoderma in some people. To explore the mechanism underlying this effect, we previously showed that the oxidation of RD with mushroom or human tyrosinase produces cytotoxic quinone oxidation products. We then examined the metabolism of RD in B16F1 melanoma cells in vitro and detected RD-pheomelanin and RD-quinone bound to non-protein and protein thiols. In this study, we examined the changes in glutathione (GSH) and cysteine in B16 cells exposed to RD for up to 24 h...
January 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/28024137/-secrets-of-the-red-headed
#19
REVIEW
Zygmunt Zdrojewicz, Małgorzata Kowalik, Adam Jagodziński
Only 1-2% of people is red-headed but in the Russian Udmurt Republic or United Kingdom they can be met more often. A specific variant of MC1R gene (R allele) is responsible for the red hair. The gene encodes a receptor for melanocortins. These substances stimulate melanocytes to product melanin- a dye of the skin which is transported to keratinocytes. It protects a cellular nucleus from ultraviolet radiation. Melanin has two types: eumelanin which is dark brown or even black and red/orange pheomelanin. The second one is mostly observed in red-headed which is caused by R allele...
December 22, 2016: Polski Merkuriusz Lekarski: Organ Polskiego Towarzystwa Lekarskiego
https://www.readbyqxmd.com/read/27988976/adaptive-downregulation-of-pheomelanin-related-slc7a11-gene-expression-by-environmentally-induced-oxidative-stress
#20
Ismael Galván, Ângela Inácio, Ana Angela Romero-Haro, Carlos Alonso-Alvarez
Pheomelanin is a sulphur-containing yellow-to-reddish pigment whose synthesis consumes the main intracellular antioxidant (glutathione; GSH) and its precursor cysteine. Cysteine used for pheomelanogenesis cannot be used for antioxidant protection. We tested whether the expression of Slc7a11, the gene regulating the transport of cysteine to melanocytes for pheomelanogenesis, is environmentally influenced when cysteine/GSH are most required for antioxidant protection. We found that zebra finches Taeniopygia guttata developing pheomelanin-pigmented feathers during a 12-day exposure to the pro-oxidant diquat dibromide downregulated the expression of Slc7a11 in feather melanocytes, but not the expression of other genes that affect pheomelanogenesis by mechanisms different from cysteine transport such as MC1R and Slc45a2...
February 2017: Molecular Ecology
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