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Conor L Evans
The natural pigments known as melanins are thought to play a role in the etiology and progression of melanoma, but many of their roles are currently not well understood. While quantification of melanins have, up until now, have been performed in bulk, new imaging technologies have unlocked the means to visualize and quantify melanins. The nonlinear imaging methods known as Pump-Probe, Coherent Raman, and Sum Frequency Absorption microscopies, provide subcellular resolution imaging of melanins, enabling label-free, longitudinal quantification of both eumelanin and pheomelanin in situ and in vivo...
February 27, 2018: Photochemistry and Photobiology
Shosuke Ito, Kazumasa Wakamatsu
-4-(4-hydroxyphenyl)-2-butanol (rhododendrol (RD))-a skin-whitening ingredient-was reported to induce leukoderma in some consumers. We have examined the biochemical basis of the RD-induced leukoderma by elucidating the metabolic fate of RD in the course of tyrosinase-catalyzed oxidation. We found that the oxidation of racemic RD by mushroom tyrosinase rapidly produces RD-quinone, which gives rise to secondary quinone products. Subsequently, we confirmed that human tyrosinase is able to oxidize both enantiomers of RD...
February 12, 2018: International Journal of Molecular Sciences
Tolga N V Karsili, Barbara Marchetti, Spiridoula Matsika
4-Hydroxybenzothiazole (HBT) is a molecular constituent of pheomelanin $-$ a polymeric skin centered pigment which acts as a natural photoprotector against harmful solar-UV radiation. Its molecular structure is therefore required to sustain a degree of photostability upon electronic excitation with UV irradiation. Despite its function as a protector against UV, pheomelanin is known to be less photostable than that of its close derivative eumelanin - a dark skin centered pigment. The HBT subunit has long being attributed as a key contributor to the lack of photostability of pheomelanin - a hypothesis which we aim to test in this manuscript...
February 2, 2018: Journal of Physical Chemistry. A
Peter Frost, Karel Kleisner, Jaroslav Flegr
Red hair is associated in women with pain sensitivity. This medical condition, and perhaps others, seems facilitated by the combination of being red-haired and female. We tested this hypothesis by questioning a large sample of Czech and Slovak respondents about the natural redness and darkness of their hair, their natural eye color, their physical and mental health (24 categories), and other personal attributes (height, weight, number of children, lifelong number of sexual partners, frequency of smoking). Red-haired women did worse than other women in ten health categories and better in only three, being particularly prone to colorectal, cervical, uterine, and ovarian cancer...
2017: PloS One
Dainan Cao, Shiping Gong, Jiangbo Yang, Weiye Li, Yan Ge, Yufeng Wei
Animal coloration primarily depends on the presence of pigments and the mixing ratio of eumelanin and pheomelanin. The color of red-eared slider's carapace varies with age, from an olive green to a yellow green, and then to a yellow brown in juveniles, generally. The purpose of the present study was to investigate whether this color change is related to the difference in melanin expression. Melanin deposition levels were examined in the carapace, skin, eye and muscle of the three color-types using hematoxylin and eosin staining...
December 18, 2017: Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
Kouichi Nakagawa, Satoko Minakawa, Daisuke Sawamura, Hideyuki Hara
Continuous wave electron paramagnetic resonance (CW EPR) and X-band (9 GHz) EPR imaging (EPRI) were used to nondestructively investigate the possible differentiation between malignant melanoma (MM) and nevus pigmentosus (NP) melanin radicals in paraffin-embedded specimens. The EPR spectra of both samples were analyzed using linewidth, spectral pattern, and X-band EPRI. The CW-EPR spectra of the MM showed an additional signal overlap. Eumelanin- and pheomelanin-related radicals were observed in the MM specimens...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Shoichi Sasamori, Andrew S Wiewel, Vicki A Thomson, Motoko Kobayashi, Katsushi Nakata, Hitoshi Suzuki
The occurrence of black fur, or melanism, in many mammalian species is known to be linked to DNA sequence variation in the agouti signaling protein (Asip) gene, which is a major determinant of eumelanin and pheomelanin pigments in coat color. We investigated 38 agouti (i.e., banded wildtype) and four melanistic Rattus rattus species complex (RrC) lineage II specimens from Okinawa Island, Ryukyu Islands, Japan, for genetic variation in three exons and associated flanking regions in the Asip gene. On Okinawa, a predicted loss-of-function mutation caused by a cysteine to serine amino acid change at p...
December 2017: Zoological Science
Naoki Oiso, Kazumasa Wakamatsu, Shigeto Yanagihara, Akira Kawada
No abstract text is available yet for this article.
November 27, 2017: European Journal of Dermatology: EJD
F Miao, T C Lei, M Y Su, W J Yi, S Jiang, S Z Xu
Objective: To compare the decolorization efficiency of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase on eumelanin and pheomelanin, and to investigate the effect of topical administration of LiP solution on hyperpigmented guinea pigs skin induced by 308 nm excimer light. Methods: Pheomelanin-enriched specimens were prepared from human hair and cutaneous melanoma tissue using alkaline lysis method.Synthetic eumelanin was purchased from a commercial supplier.The same amount (0.02%) of melanin was incubated with the equal enzyme activity (0...
November 21, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Shosuke Ito, Shiho Miyake, Shoji Maruyama, Itaru Suzuki, Stéphane Commo, Yukiko Nakanishi, Kazumasa Wakamatsu
We previously reported a constant ratio of the benzothiazole pheomelanin marker thiazole-2,4,5-tricarboxylic acid (TTCA) to the eumelanin marker pyrrole-2,3,5-tricarboxylic acid (PTCA) in eumelanic, black human hair. A constant level (20%-25%) of benzothiazole-type pheomelanin was recently demonstrated in human skin with varying concentrations of melanin. Therefore, in this study, we aimed to investigate the origin of pheomelanin markers in black to brown human hair by developing a method to remove protein components from hair by heating with 6 M HCl at 110°C for 16 hr...
November 24, 2017: Pigment Cell & Melanoma Research
Hanine Barek, Manickam Sugumaran, Shosuke Ito, Kazumasa Wakamatsu
Melanin from several insect samples was 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 is derived from the oxidative polymerization of both 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acids. 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
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
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
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
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
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
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
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
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
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
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