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https://www.readbyqxmd.com/read/29225224/characterization-of-melanin-radicals-in-paraffin-embedded-malignant-melanoma-and-nevus-pigmentosus-using-x-band-epr-and-epr-imaging
#1
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
https://www.readbyqxmd.com/read/29219041/potential-causative-mutation-for-melanism-in-rats-identified-in-the-agouti-signaling-protein-gene-asip-of-the-rattus-rattus-species-complex-on-okinawa-island-japan
#2
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
https://www.readbyqxmd.com/read/29211110/evaluation-of-melanin-production-by-sporothrix-luriei
#3
Ingrid Ludmilla Rodrigues Cruz, Maria Helena Galdino Figueiredo-Carvalho, Rosely Maria Zancopé-Oliveira, Rodrigo Almeida-Paes
There is a paucity of studies on the cell biology of Sporothrix luriei, the less common of the pathogenic Sporothrix species worldwide. The production of DHN-melanin, eumelanin, and pyomelanin were evaluated on the mycelial and yeast forms of the S. luriei ATCC 18616 strain. The mycelial form of this species produced only pyomelanin, which protected the fungus against environmental stressors such as ultraviolet light, heat, and cold. The yeast form was unable to produce any of the tested melanin types. The lack of melanin in the parasitic form of S...
January 2018: Memórias do Instituto Oswaldo Cruz
https://www.readbyqxmd.com/read/29179286/-decolorization-of-skin-and-hair-derived-melanin-by-three-ligninolytic-enzymes
#4
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]
https://www.readbyqxmd.com/read/29171182/acid-hydrolysis-reveals-a-low-but-constant-level-of-pheomelanin-in-human-black-to-brown-hair
#5
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-tricaboxylic 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 h...
November 24, 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/29160957/insect-cuticular-melanins-are-distinctly-different-from-those-of-mammalian-epidermal-melanins
#6
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/29124869/polydopamine-based-colloidal-materials-synthesis-and-applications
#7
REVIEW
Ziwei Deng, Bin Shang, Bo Peng
Polydopamine is a synthetic analogue of natural melanin (eumelanin) produced from oxidative polymerization of dopamine. Owing to its strong adhesion ability, versatile chemical reactivity, biocompatibility and biodegradation, polydopamine is commonly applied as a versatile linker to synthesize colloidal materials with diverse structures, unique physicochemical properties and tunable functions, which allow for a broad scope of applications including biomedicine, sensing, catalysis, environment and energy. In this personal account, we discuss first about the different synthetic approaches of polydopamine, as well as its polymerization mechanism, and then with a comprehensive overview of recent progress in the synthesis and applications of polydopamine-based colloidal materials...
November 10, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/29124695/photodermatoses-in-the-pigmented-skin
#8
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/29083852/eumelanin-coated-pla-electrospun-micro-fibers-as-bio-inspired-cradle-for-sh-sy5y-neuroblastoma-cells-growth-and-maturation
#9
Ines Fasolino, Irene Bonadies, Luigi Ambrosio, Maria Grazia Raucci, Cosimo Carfagna, Federica Maria Caso, Francesca Cimino, Alessandro Pezzella
Within the framework of neurodegenerative disorder therapies, the fabrication of 3D eumelanin architectures represents a novel strategy to realize tissue-engineering scaffolds for neuronal cell growth and control by providing both mechanical support and biological signals. Here, an appropriate procedure combining electrospinning, spin coating and solid-state polymerization process is established to realize the scaffolds. For biological analysis, a human derived cell line SH-SY5Y from neuroblastoma is used. Cell maturation on eumelanin microfibers, random and aligned, is evaluated by using confocal analysis and specific markers of differentiating neurons (βIII tubulin and GAP-43 expression)...
October 30, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29051758/identification-of-yfih-and-the-catalase-cata-as-polyphenol-oxidases-of-aeromonas-media-and-cata-as-a-regulator-of-pigmentation-by-its-peroxyl-radical-scavenging-capacity
#10
Baozhong Chai, Yunqian Qiao, He Wang, Xiaoming Zhang, Jiao Wang, Choushi Wang, Ping Zhou, Xiangdong Chen
Pyomelanin is the major constituent of pigment in melanogenic Aeromonas strains of bacteria. However, eumelanin, synthesized from tyrosine via L-DOPA and polyphenol oxidases (PPOs), may also be present in this genus since L-DOPA is frequently detected in culture fluids of several species. To address this question, we used a deletion mutant of Aeromonas media strain WS, in which pyomelanin synthesis is completely blocked under normal culture conditions. When tyrosine was supplied to the medium, we observed residual melanin accumulation, which we interpret as evidence for existence of the DOPA-melanin pathway...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29044987/sticky-fingers-at-work-palmitoylation-dependent-mc1r-activation
#11
Jose Carlos Garcia-Borron, Celia Jimenez-Cervantes
No abstract text is available yet for this article.
October 17, 2017: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/29039817/replacing-nitrogen-by-sulfur-from-structurally-disordered-eumelanins-to-regioregular-thiomelanin-polymers
#12
Mariagrazia Iacomino, Juan Mancebo-Aracil, Mireia Guardingo, Raquel Martín, Gerardino D'Errico, Marco Perfetti, Paola Manini, Orlando Crescenzi, Félix Busqué, Alessandra Napolitano, Marco d'Ischia, Josep Sedó, Daniel Ruiz-Molina
The oxidative polymerization of 5,6-dihydroxybenzothiophene (DHBT), the sulfur analog of the key eumelanin building block 5,6-dihydroxyindole (DHI), was investigated to probe the role of nitrogen in eumelanin build-up and properties. Unlike DHI, which gives a typical black insoluble eumelanin polymer on oxidation, DHBT is converted to a grayish amorphous solid (referred to as thiomelanin) with visible absorption and electron paramagnetic resonance properties different from those of DHI melanin. Mass spectrometry experiments revealed gradational mixtures of oligomers up to the decamer level...
October 17, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29022703/probing-the-eumelanin-silica-interface-in-chemically-engineered-bulk-hybrid-nanoparticles-for-targeted-subcellular-antioxidant-protection
#13
Brigida Silvestri, Giuseppe Vitiello, Giuseppina Luciani, Vincenzo Calcagno, Aniello Costantini, Maria Gallo, Silvia Parisi, Simona Paladino, Mariagrazia Iacomino, Gerardino D'Errico, M Federica Caso, Alessandro Pezzella, Marco d'Ischia
We disclose herein the first example of stable monodispersed hybrid nanoparticles (termed MelaSil-NPs) made up of eumelanin biopolymer intimately integrated into a silica nanoscaffold matrix and endowed with high antioxidant and cytoprotective effects associated with a specific subcellular localization. MelaSil-NPs have been fabricated by an optimized sol-gel methodology involving ammonia-induced oxidative polymerization of a covalent conjugate of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) with 3-aminopropyltriethoxysilanes (APTS)...
October 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28937213/structural-basis-of-polydopamine-film-formation-probing-5-6-dihydroxyindole-based-eumelanin-type-units-and-the-porphyrin-issue
#14
Maria L Alfieri, Raffaella Micillo, Lucia Panzella, Orlando Crescenzi, Stefano L Oscurato, Pasqualino Maddalena, Alessandra Napolitano, Vincent Ball, Marco d'Ischia
The role of 5,6-dihydroxyindole (DHI)-based oligomers, including porphyrin-like tetramers, in polydopamine (PDA) film formation was addressed by a comparative structural investigation against model polymers from DHI and its 2,7'-dimer. MALDI-MS data showed that (a) PDA is structurally different from DHI melanin and does not contain species compatible with DHI-based oligomers as primary building blocks; (b) PDA films and precipitate display a single main peak at m/z 402 in common; (c) no species matching the range of m/z values expected for cyclic porphyrin-type tetramers was detected in DHI melanin produced in the presence or in the absence of folic acid (FA) as templating agent, nor by oxidation of the 2,7'-dimer of DHI as putative precursor...
September 29, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28878140/the-supramolecular-buildup-of-eumelanin-structures-mechanisms-controllability
#15
REVIEW
Anne Büngeler, Benjamin Hämisch, Oliver I Strube
Research on the supramolecular buildup of eumelanin has gained high momentum in the last years. Several new aspects regarding the involved structures and mechanisms have been established, which has led to a better understanding of the entire process. This review intends to provide a clearly laid-out summary of previous and new findings regarding structures, mechanisms, and controllability. With respect to materials applications, the aspect of controllability is of supreme importance. A focus of this review is therefore set on a novel method with high potential for specific synthesis of various, isolated particle morphologies...
September 6, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28878021/ck1%C3%AE-ablation-in-keratinocytes-induces-p53-dependent-sunburn-protective-skin-hyperpigmentation
#16
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
#17
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/28753933/deciphering-molecular-mechanisms-of-interface-buildup-and-stability-in-porous-si-eumelanin-hybrids
#18
Elisa Pinna, Claudio Melis, Aleandro Antidormi, Roberto Cardia, Elisa Sechi, Giancarlo Cappellini, Marco d'Ischia, Luciano Colombo, Guido Mula
Porous Si/eumelanin hybrids are a novel class of organic-inorganic hybrid materials that hold considerable promise for photovoltaic applications. Current progress toward device setup is, however, hindered by photocurrent stability issues, which require a detailed understanding of the mechanisms underlying the buildup and consolidation of the eumelanin-silicon interface. Herein we report an integrated experimental and computational study aimed at probing interface stability via surface modification and eumelanin manipulation, and at modeling the organic-inorganic interface via formation of a 5,6-dihydroxyindole (DHI) tetramer and its adhesion to silicon...
July 19, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28753659/melanic-variation-underlies-aposematic-color-variation-in-two-hymenopteran-mimicry-systems
#19
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/28746990/identification-of-a-gene-involved-in-the-negative-regulation-of-pyomelanin-production-in-ralstonia-solanacearum
#20
Shabir Ahmad, Seung Yeup Lee, Raees Khan, Hyun Gi Kong, Geun Ju Son, Nazish Roy, Kihyuck Choi, Seon-Woo Lee
Ralstonia solanacearum causes bacterial wilt in a wide variety of host plant species and produces a melanin-like blackish-brown pigment in stationary phase when grown in minimal medium supplemented with tyrosine. To study melanin production regulation in R. solanacearum, five mutants exhibiting overproduction of melanin-like pigments were selected from a transposon (Tn) insertion mutant library of R. solanacearum SL341. Most of the mutants, except one (SL341T), were not complemented by the original gene or overproduced melanins...
September 28, 2017: Journal of Microbiology and Biotechnology
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