WorldWideScience

Sample records for melanins

  1. Photoelectrochemical properties of melanin

    OpenAIRE

    Arturo Solis; Maria E. Lara; Luis E. Rendon

    2007-01-01

    Melanin is to the animal kingdom like chlorophyll to the vegetal kingdom(1). Melanin collects energy from lower-energy radiation sources, kicks electrons into excited states, initiating a process that would end up producing chemical energy, similar to the way in which photosynthesis supplies energy to plants. However, the precise roles of melanin during this process are unknown. Here we show that the increase in the electron-transfer properties of melanin is independent of the energy of the i...

  2. Fluorescent quantification of melanin

    OpenAIRE

    Fernandes, Bruno Pacheco; Matamá, Maria Teresa; Guimarães, Diana Isabel Pereira; Gomes, Andreia; Cavaco-Paulo, Artur

    2016-01-01

    Melanin quantification is reportedly performed by absorption spectroscopy, commonly at 405 nm. Here, we propose the implementation of fluorescence spectroscopy for melanin assessment. In a typical in vitro assay to assess melanin production in response to an external stimulus, absorption spectroscopy clearly overvalues melanin content. This method is also incapable of distinguishing non-melanotic/amelanotic control cells from those that are actually capable of performing melanogenesis. Theref...

  3. Antiradiation properties of melanin

    OpenAIRE

    Bushmanov A.Ju.; Ivanov А.А.; Andrianova I.E.; Stavrakova N.M.; Bulinina T.M.; Dorozhkina O.V.

    2014-01-01

    Aim: to examine the therapeutic efficiency of melanin administered to mice after irradiation at lethal and sublethal doses. Material and methods: Survival and hematological states were studied on CD-1 mice receiving on acute or fractionated whole-body doses on X-rays or gamma-irradiation. Melanin soluble was given with water ad libitum from the first to the 30th-day after irradiation. Results. It was shown that melanin produced a significant therapeutic and protective-therapeutic action again...

  4. Melanin-binding radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Packer, S; Fairchild, R G; Watts, K P; Greenberg, D; Hannon, S J

    1980-01-01

    The scope of this paper is limited to an analysis of the factors that are important to the relationship of radiopharmaceuticals to melanin. While the authors do not attempt to deal with differences between melanin-binding vs. melanoma-binding, a notable variance is assumed. (PSB)

  5. Melanin-binding radiopharmaceuticals

    International Nuclear Information System (INIS)

    Packer, S.; Fairchild, R.G.; Watts, K.P.; Greenberg, D.; Hannon, S.J.

    1980-01-01

    The scope of this paper is limited to an analysis of the factors that are important to the relationship of radiopharmaceuticals to melanin. While the authors do not attempt to deal with differences between melanin-binding vs. melanoma-binding, a notable variance is assumed

  6. Antiradiation properties of melanin

    Directory of Open Access Journals (Sweden)

    Bushmanov A.Ju.

    2014-12-01

    Full Text Available Aim: to examine the therapeutic efficiency of melanin administered to mice after irradiation at lethal and sublethal doses. Material and methods: Survival and hematological states were studied on CD-1 mice receiving on acute or fractionated whole-body doses on X-rays or gamma-irradiation. Melanin soluble was given with water ad libitum from the first to the 30th-day after irradiation. Results. It was shown that melanin produced a significant therapeutic and protective-therapeutic action against acute radiation injury in the dose range 6,5-7,5 Gy (LD80-LD under our conditions. Cumulative survival melanin treated mice was increased to 14,4%, in control group — 1,9%. After fractionated injury (1 Gy daily, total dose 10 Gy all mice which consumed melanin remained alive, versus 43,7% in control. Melanin decreased radiation-induced damage and stimulated the hematopoiesis recovery after sublethal exposure (5Gy. Conclusion. The results permit to regard melanin as a therapeutic agent for treatment of radiation injuries.

  7. Melanin, melanin "ghosts," and melanin composition in Cryptococcus neoformans.

    OpenAIRE

    Wang, Y; Aisen, P; Casadevall, A

    1996-01-01

    Melanin synthesis is associated with virulence for the pathogenic fungus Cryptococcus neoformans. Exposure of nonmelanized C. neoformans 4067 cells to 4 M guanidinium isothiocyanate followed by 6 M HCl at 100 degrees C resulted in complete solubilization of cellular structures. However, exposure of melanized C. neoformans 24067 to the same conditions produced a suspension of black particles. Analysis of black particles with transmission and scanning electron microscopy revealed cell "ghosts" ...

  8. Photothermal imaging of melanin

    Science.gov (United States)

    Kerimo, Josef; DiMarzio, Charles A.

    2013-02-01

    We present photothermal images of melanin using modulation with two laser beams. Strong melanin absorption followed by efficient nonradiative relaxation caused heating and an increase in temperature. This temperature effect was used as an imaging contrast to detect melanin. Melanin from several samples including Sepia officinalis, black human hair, and live zebra fish, were imaged with a high signal-to-noise ratio. For the imaging, we focused two near infrared laser beams (pump and probe) collinearly with different wavelengths and the pump was modulated in amplitude. The thermally induced variations in the refractive index, at the modulation frequency, were detected by the scattering of the probe beam. The Photothermal method brings several imaging benefits including the lack of background interference and the possibility of imaging for an extended period of time without photodamage to the melanin. The dependence of the photothermal signal on the laser power, modulation frequency, and spatial offset of the probe is discussed. The new photothermal imaging method is promising and provides background-free and label-free imaging of melanin and can be implemented with low-cost CW lasers.

  9. Melanin pigmented solar absorbing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gallas, J.M.; Eisner, M.

    1980-01-01

    Selectivity enhancement is shown to result for melanin, a black biopolymer pigment, for sufficiently low sample density. The effect is proposed to follow from a consideration of the evanescent waves associated with the total internal reflection phenomenon. A relationship is discussed among powder density, pH and the paramagnetic properties of melanin; this relationship is shown to be consistent with, and offer support to an amino-acid side group proposed earlier as part of the melanin structure. A brief discussion is also presented on the optical properties of melanin and the relative importance of quinhydrone, a change transfer complex believed to exist in the polymeric structure of melanin.

  10. Antibodies Against Melanin

    African Journals Online (AJOL)

    1973-01-06

    Jan 6, 1973 ... as often quoted, to an auto-immune aetiology of vitiligo;. (ii) its significance regarding the current problem of melanin structure, whether it is a homopolymer, formed by the linkage of a single monomer (indole-5, 6-quinone) or a poikilopolymer, formed by the irregular random bonding of several types of ...

  11. Melanin-Based Functional Materials.

    Science.gov (United States)

    d'Ischia, Marco

    2018-01-12

    Melanin biopolymers are currently the focus of growing interest for a broad range of applications at the cutting edge of biomedical research and technology. This Special Issue presents a collection of papers dealing with melanin-type materials, e.g., polydopamine, for classic and innovative applications, offering a stimulating perspective of current trends in the field. Besides basic scientists, the Special Issue is directed to researchers from industries and companies that are willing to invest in melanin research for innovative and inspiring solutions.

  12. Melanin-Based Functional Materials

    Directory of Open Access Journals (Sweden)

    Marco d’Ischia

    2018-01-01

    Full Text Available Melanin biopolymers are currently the focus of growing interest for a broad range of applications at the cutting edge of biomedical research and technology. This Special Issue presents a collection of papers dealing with melanin-type materials, e.g., polydopamine, for classic and innovative applications, offering a stimulating perspective of current trends in the field. Besides basic scientists, the Special Issue is directed to researchers from industries and companies that are willing to invest in melanin research for innovative and inspiring solutions.

  13. Melanin pigmentary disorders: treatment update.

    Science.gov (United States)

    Ortonne, Jean-Paul; Passeron, Thierry

    2005-04-01

    Most of the melanin pigmentary disorders are cosmetically important and have a strong impact on the quality of life of affected individuals. This article examines recent advances in the treatment of melanin pigmentary disorder including hypermelanosis and hypomelanosis. The development of laser technologies has completed the use of the increasing number of bleaching agents in treating hyperpigmented lesions. The treatment of hypomelanotic disorders is still often disappointing, but new therapeutic options provide encouraging results.

  14. Melanin-Based Functional Materials

    OpenAIRE

    Marco d’Ischia

    2018-01-01

    Melanin biopolymers are currently the focus of growing interest for a broad range of applications at the cutting edge of biomedical research and technology. This Special Issue presents a collection of papers dealing with melanin-type materials, e.g., polydopamine, for classic and innovative applications, offering a stimulating perspective of current trends in the field. Besides basic scientists, the Special Issue is directed to researchers from industries and companies that are willing to inv...

  15. Computational model of heterogeneous heating in melanin

    Science.gov (United States)

    Kellicker, Jason; DiMarzio, Charles A.; Kowalski, Gregory J.

    2015-03-01

    Melanin particles often present as an aggregate of smaller melanin pigment granules and have a heterogeneous surface morphology. When irradiated with light within the absorption spectrum of melanin, these heterogeneities produce measurable concentrations of the electric field that result in temperature gradients from thermal effects that are not seen with spherical or ellipsoidal modeling of melanin. Modeling melanin without taking into consideration the heterogeneous surface morphology yields results that underestimate the strongest signals or over{estimate their spatial extent. We present a new technique to image phase changes induced by heating using a computational model of melanin that exhibits these surface heterogeneities. From this analysis, we demonstrate the heterogeneous energy absorption and resulting heating that occurs at the surface of the melanin granule that is consistent with three{photon absorption. Using the three{photon dluorescence as a beacon, we propose a method for detecting the extents of the melanin granule using photothermal microscopy to measure the phase changes resulting from the heating of the melanin.

  16. Fourier transform infrared spectroscopy for sepia melanin

    CSIR Research Space (South Africa)

    Mbonyiryivuze, A

    2015-08-01

    Full Text Available range of electromagnetic radiation, antibiotic, thermoregulation. Melanins are found all over the body from the skin and blood to the nervous system but the role of melanin in all these system is unclear. FTIR spectroscopy technique is usually one...

  17. Synthesis and characterization of melanin in DMSO

    Science.gov (United States)

    Bronze-Uhle, Erika S.; Batagin-Neto, Augusto; Xavier, Pedro H. P.; Fernandes, Nicole I.; de Azevedo, Eduardo R.; Graeff, Carlos F. O.

    2013-09-01

    Recently soluble melanin derivatives have been obtained by a synthetic procedure carried out in DMSO (D-melanin). In this work a comparative study of the structural characteristics of synthetic melanin derivatives obtained by oxidation of L-DOPA in H2O and DMSO are presented. To this end, Fourier-transform infrared spectroscopy as well as proton and carbon nuclear magnetic resonance techniques has been employed. In addition, aging effects have been investigated for D-melanin. The results suggest that sulfonate groups (-SO2CH3) from the oxidation of DMSO, are incorporated into melanin, which confers protection to the phenolic hydroxyl group present in its structure. The solubility of D-melanin in DMSO is attributed to the presence of these groups. When D-melanin is left in air for long time periods, the sulfonate groups leave the structure, and an insoluble compound is obtained. NaOH and water have been used, in order to accelerate the release of the sulfonate groups attached to D-melanin, thereby corroborating the proposed structure and the synthesis mechanism.

  18. Fungal melanins and their interactions with metals.

    Science.gov (United States)

    Fogarty, R V; Tobin, J M

    1996-09-01

    Fungal melanins are dark brown or black pigments located in cell walls. They also exist as extracellular polymers. Melanized fungi possess increased virulence and resistance to microbial attack as well as enhanced survival while under environmental stress. Melanins contain various functional groups which provide an array of multiple nonequivalent binding sites for metal ions. Pigmented Cladosporium cladosporoides was shown to biosorb 2.5- to four-fold more Ni, Cu, Zn, Cd, and Pb than albino Penicillium digitatum and at four- to six-fold higher rates. Metal desorption was significantly lower for extracellular melanin than from pigmented or albino biomass which indicated the strength of the melanin-metal bond. At equilibrium, tributyltin chloride (TBTC) concentrations of 2.5 mM, pigmented and albino Aureobasidium pullulans absorbed approximately 0.9 and 0.7 mumol TBTC mg -1 dry wt, respectively, whereas purified extracellular melanin exhibited uptake levels of approximately 22 mumol TBTC mg-1 dry wt at an equilibrium concentration of only 0.4 mM. Addition of melanin to the growth medium reduced the toxic effect of CuSO4 and TBTC due to melanin metal binding and sequestration.

  19. Evaluation of melanin production by Sporothrix luriei

    Directory of Open Access Journals (Sweden)

    Ingrid Ludmilla Rodrigues Cruz

    Full Text Available 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. luriei may be an explanation for its low frequency in human infections.

  20. Evaluation of melanin production by Sporothrix luriei.

    Science.gov (United States)

    Cruz, Ingrid Ludmilla Rodrigues; Figueiredo-Carvalho, Maria Helena Galdino; Zancopé-Oliveira, Rosely Maria; Almeida-Paes, Rodrigo

    2018-01-01

    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. luriei may be an explanation for its low frequency in human infections.

  1. A melanin-mediated cancer immunotherapy patch.

    Science.gov (United States)

    Ye, Yanqi; Wang, Chao; Zhang, Xudong; Hu, Quanyin; Zhang, Yuqi; Liu, Qi; Wen, Di; Milligan, Joshua; Bellotti, Adriano; Huang, Leaf; Dotti, Gianpietro; Gu, Zhen

    2017-11-10

    Melanin is capable of transforming 99.9% of the absorbed sunlight energy into heat, reducing the risk of skin cancer. We here develop a melanin-mediated cancer immunotherapy strategy through a transdermal microneedle patch. B16F10 whole tumor lysate containing melanin is loaded into polymeric microneedles that allow sustained release of the lysate upon insertion into the skin. In combination with the near-infrared light irradiation, melanin in the patch mediates the generation of heat, which further promotes tumor-antigen uptake by dendritic cells, and leads to enhanced antitumor vaccination. We found that the spatiotemporal photoresponsive immunotherapy increases infiltration of polarized T cells and local cytokine release. These immunological effects increase the survival of mice after tumor challenge and elicited antitumor effects toward established primary tumor and distant tumor. Collectively, melanin generates local heat, boosts T cell activities by transdermal vaccines, and promotes antitumor immune responses. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  2. Bleaching of melanin pigments. Role of copper ions and hydrogen peroxide in autooxidation and photooxidation of synthetic dopa-melanin.

    Science.gov (United States)

    Korytowski, W; Sarna, T

    1990-07-25

    Bleaching of eumelanin has been studied in model systems consisting of synthetic dopa-melanin and various concentrations of hydrogen peroxide, molecular oxygen, and copper(II) ions at neutral and alkaline pH. The data show that at neutral pH, in the dark, metal-ion-free melanin is very resistant to oxidation by hydrogen peroxide. However, the rate of bleaching of melanin, induced by H2O2 is significantly accelerated by illumination from UVA-visible light. Bound-to-melanin copper(II) also accelerates the bleaching of melanin with the efficiency dependent on concentration of H2O2 and oxygen. It suggests possible involvement of melanin-copper complexes in Fenton-like processes. The formation of hydroxyl radicals during melanin bleaching has been concluded on the basis of the electrochemical detection of hydroxylation products of salicylate used as OH scavenger. Redox conversion of bound-to-melanin copper ions was monitored by EPR spectroscopy and direct measurement of melanin-Cu(II) complexes. It has been shown that melanin-copper(I) complexes were readily oxidized by either oxygen or hydrogen peroxide. The data indicate that bleaching of melanin is a complex process with two distinct stages, reversible oxidation of the hydroquinone moieties of melanin followed by irreversible reactions of the monomers that lead to degradation of the melanin polymer.

  3. Morphological and chemical composition characterization of commercial sepia melanin

    CSIR Research Space (South Africa)

    Mbonyiryivuze, A

    2015-06-01

    Full Text Available Melanins are difficult to characterize because of their intractable chemical properties and the heterogeneity in their structural features. Melanin pigments, in fact, are composed of many different types of monomeric units that are connected through...

  4. Optical and photoelectronic properties of melanin

    Energy Technology Data Exchange (ETDEWEB)

    Capozzi, V. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy)]|[Istituto Nazionale di Fisica della Materia, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Perna, G. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy)]|[Istituto Nazionale di Fisica della Materia, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Carmone, P. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy); Gallone, A. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy); Lastella, M. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy); Mezzenga, E. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy); Quartucci, G. [Dipartimento di Scienze Biomediche, Universita di Foggia, Viale Pinto, I-71100 Foggia (Italy); Ambrico, M. [Istituto di Metodologie Inorganiche e dei Plasmi del C.N.R., Via Orabona 4, I-70126 Bari (Italy); Augelli, V.; Biagi, P.F.; Ligonzo, T.; Minafra, A.; Schiavulli, L. [Istituto Nazionale di Fisica della Materia, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy)]|[Dipartimento Interateneo di Fisica, Universita di Bari, Via Amendola 173, I-70126 Bari (Italy); Pallara, M. [Dipartimento Geomineralogico, Universita di Bari, via Amendola 173, Bari (Italy); Cicero, R. [Dipartimento di Biochimica Medica e Biologia Medica, Sezione di Biologia Medica, Facolta di Medicina e Chirurgia, Universita di Bari, Policlinico, I-70124 Bari (Italy)

    2006-07-26

    A study of the structural, optical and electrical properties of synthetic and natural melanin by means of X-ray diffraction, absorption and photocurrent techniques is reported. The model of the natural melanin film as a network of nano-aggregates of polymeric units based on the indolic structure is proposed to explain the X-ray diffraction results. The shape of the absorption spectra is similar to that of amorphous and disordered semiconductors, with a very strong, broad band UV and visible absorption and an optical gap value of about 0.5 eV. Photosensitivity to sun spectra has been demonstrated by photoconductivity measurements of synthetic melanin pellets under AM1 light source illumination.

  5. Bacterial melanin promotes recovery after sciatic nerve injury in rats

    OpenAIRE

    Olga V Gevorkyan; Irina B Meliksetyan; Tigran R Petrosyan; Anichka S Hovsepyan

    2015-01-01

    Bacterial melanin, obtained from the mutant strain of Bacillus Thuringiensis, has been shown to promote recovery after central nervous system injury. It is hypothesized, in this study, that bacterial melanin can promote structural and functional recovery after peripheral nerve injury. Rats subjected to sciatic nerve transection were intramuscularly administered bacterial melanin. The sciatic nerve transected rats that did not receive intramuscular administration of bacterial melanin served as...

  6. Degradation of melanin by Aspergillus fumigatus.

    Science.gov (United States)

    Luther, J P; Lipke, H

    1980-07-01

    A strain of Aspergillus fumigatus from composted coffee and garden wastes utilized natural deproteinized insect, banana, hair, octopus, and synthetic tyrosine and dopa melanins as sole sources of carbon. With a sucrose supplement, degradation was essentially complete after 50 days in Czapek medium pH 6.5 at 30 degrees C. The catabolic rate differed for each substrate pigment, as did the molecular weight distribution of products accumulating in the medium. After incubation with L-[U-14C]melanin, over 50% was recovered in a dark fungal pigment, the remainder appearing as cell protein, chitin, lipid, CO2, and polar metabolites. When grown on melanin, the normally pale mycelia darkened with the production of a fungal allomelanin, with infrared spectrum and alkali fusion products differing from those of the substrate pigment. Isotope distribution in amino acids for A. fumigatus grown on labeled melanin supplemented with sucrose suggested separate pools for synthesis of cell proteins and melanoproteins. Deposition of allomelanin increased resistance of conidia, sterigma, and conidiophores to lytic carbohydrases as judged by scanning electron microscopy.

  7. Antibodies Against Melanin | Wassermann | South African Medical ...

    African Journals Online (AJOL)

    This study reports on unsuccessful attempts to produce antibodies against melanoprotein in rabbits. Available evidence suggests antibodies against melanocytes in the aetiology of vitiligo, but there is no convincing evidence for antibodies against melanin per se. It is suggested that the demonstration of antibodif's against ...

  8. Melanin production from marine Streptomyces | Vasanthabharathi ...

    African Journals Online (AJOL)

    Melanin pigments are frequently used in medicine, food and cosmetic preparations. In this study, three strains among 21 Actinomycetes sp isolates produced a diffusible dark pigment on starch casein an agar medium which was water soluble. The pigment production was estimated using L-tyrosine as substrate. Among the ...

  9. Melanin as an active layer in biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Piacenti da Silva, Marina, E-mail: marinaness@yahoo.com; Congiu, Mirko, E-mail: congiumat@gmail.com; Oliveira Graeff, Carlos Frederico de, E-mail: graeff@fc.unesp.br [Department of Physics, Faculty of Sciences - UNESP, Bauru, SP (Brazil); Fernandes, Jéssica Colnaghi, E-mail: jeziga-cf@yahoo.com.br; Biziak de Figueiredo, Natália, E-mail: natbiziak@yahoo.com.br; Mulato, Marcelo, E-mail: mmulato@ffclrp.usp.br [Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)

    2014-03-15

    The development of pH sensors is of great interest due to its extensive application in several areas such as industrial processes, biochemistry and particularly medical diagnostics. In this study, the pH sensing properties of an extended gate field effect transistor (EGFET) based on melanin thin films as active layer are investigated and the physical mechanisms related to the device operation are discussed. Thin films were produced from different melanin precursors on indium tin oxide (ITO) and gold substrates and were investigated by Atomic Force Microscopy and Electrochemical Impedance Spectroscopy. Experiments were performed in the pH range from 2 to 12. EGFETs with melanin deposited on ITO and on gold substrates showed sensitivities ranging from 31.3 mV/pH to 48.9 mV/pH, depending on the melanin precursor and the substrate used. The pH detection is associated with specific binding sites in its structure, hydroxyl groups and quinone imine.

  10. Melanin as an active layer in biosensors

    Science.gov (United States)

    Piacenti da Silva, Marina; Fernandes, Jéssica Colnaghi; de Figueiredo, Natália Biziak; Congiu, Mirko; Mulato, Marcelo; de Oliveira Graeff, Carlos Frederico

    2014-03-01

    The development of pH sensors is of great interest due to its extensive application in several areas such as industrial processes, biochemistry and particularly medical diagnostics. In this study, the pH sensing properties of an extended gate field effect transistor (EGFET) based on melanin thin films as active layer are investigated and the physical mechanisms related to the device operation are discussed. Thin films were produced from different melanin precursors on indium tin oxide (ITO) and gold substrates and were investigated by Atomic Force Microscopy and Electrochemical Impedance Spectroscopy. Experiments were performed in the pH range from 2 to 12. EGFETs with melanin deposited on ITO and on gold substrates showed sensitivities ranging from 31.3 mV/pH to 48.9 mV/pH, depending on the melanin precursor and the substrate used. The pH detection is associated with specific binding sites in its structure, hydroxyl groups and quinone imine.

  11. Renal cell carcinoma with melanin pigment

    Science.gov (United States)

    Shetty, Jayaprakash; Chandrika; Laxman, Prabhu

    2010-01-01

    The incidence of renal cell carcinoma has been steadily increasing. There are several morphological types of renal cell carcinoma. Recognizing histologic patterns of renal cell carcinoma is important for correct diagnosis and subsequent medical care for the patient. Melanotic tumors in the kidney are very rare. Here, we present an unusual case of renal cell carcinoma with melanin pigment. PMID:20877613

  12. Melanin: A scavenger in gingival inflammation

    Directory of Open Access Journals (Sweden)

    S Nilima

    2011-01-01

    Full Text Available Background: One of the major direct or indirect targets of ultraviolet exposure of skin is the melanocyte or the melanin -forming cell. Epidermal melanocytes act as a trap for free radicals. Based on the protective role of melanocytes in medical literature, the role of melanin pigmentation in gingiva needs to be elucidated. Periodontal pathogens and their products demonstrate the ability to induce the generation of reactive oxygen species. Hence purpose of this study was to unravel the protective role of melanin (if any against the gingival inflammation. Materials and Methods: A total of 80 subjects; 20 in each group were selected. The selection of subjects regarding gingival pigmentation was based on Dummett′s scoring criteria 0, 3. A complete medical, dental history and an informed consent were obtained from the patients. After evaluation of clinical parameters the GCF was collected using microcapillary pipettes at the selected sites. IL-1β levels were quantitated using ELISA. Results: In non-pigmented healthy and gingivitis groups, there was a positive correlation between plaque index, gingival index and bleeding index versus IL-1β level: indicating an increase in the biochemical mediator of inflammation corresponding to an increase in the clinical parameters of inflammation. Also a positive correlation was found between the gingival index and bleeding index versus the IL-1β levels in the pigmented healthy group. The pigmented gingivitis groups showed a negative correlation between the plaque index, gingival index and bleeding index. Conclusions: The clinical markers of inflammation such as gingival index, bleeding index was of low numerical value in pigmented group than in the non-pigmented group, supposedly due to the protective action of melanin. The negative correlation of clinical markers of inflammation to the IL-1β levels in the pigmented gingivitis group could possibly be attributed to the protective role of melanins.

  13. Interaction of radicals from water radiolysis with melanin

    Energy Technology Data Exchange (ETDEWEB)

    Sarna, T.; Pilas, B.; Land, E.J.; Truscott, T.G.

    1986-08-06

    Melanins are considered to be natural photoprotectors in the melanocytes and keratinocytes of the skin. These pigments have also been suggested to play an important role in protection of melanin-containing cells against ionising radiation. Various mechanisms have been proposed to explain the protective role of melanin which invoke the radical scavenging properties of the polymer. In the present work the reactions of melanins with radicals generated in aqueous media by pulse radiolysis have been studied. Time-resolved changes in absorbance of the melanin or the radical species were recorded at selected wavelengths. Experiments were carried out on synthetic dopa- and 5-S-cysteinyldopa-melanins and a natural melanin in phosphate buffer (pH 7.4). Under the conditions employed, melanin reacted predominantly with either oxidising (OH., N3.) or reducing (eaq-, CO2-) species. We were also able to monitor the interaction of melanin with superoxide radical, which was reducing in this case. Detailed analysis of transient changes in melanin absorbance, detected at different wavelengths, was demonstrated to be a convenient method for studying redox processes of this substance, as shown by model experiments using ferricyanide and dithionite as oxidising and reducing agents, respectively. Among the radicals studied, OH. exhibited the strongest reactivity with melanins. Apparent rate constants for the reactions of radicals with autoxidative dopa-melanin (1.5 X 10(9) M-1 X s-1, 2.6 X 10(8) M-1 X s-1, 1.8 X 10(8) M-1 X s-1, 5 X 10(5) M-1 X s-1, 10(6)-10(7) M-1 X s-1 for OH., eaq-, N.3. O2- and CO2-, respectively) are reported. The reactivity of melanins with radicals from water radiolysis and their effect on pigment properties are discussed in terms of the structure and possible biological role of the pigments.

  14. Bioinspired bright noniridescent photonic melanin supraballs.

    Science.gov (United States)

    Xiao, Ming; Hu, Ziying; Wang, Zhao; Li, Yiwen; Tormo, Alejandro Diaz; Le Thomas, Nicolas; Wang, Boxiang; Gianneschi, Nathan C; Shawkey, Matthew D; Dhinojwala, Ali

    2017-09-01

    Structural colors enable the creation of a spectrum of nonfading colors without pigments, potentially replacing toxic metal oxides and conjugated organic pigments. However, significant challenges remain to achieve the contrast needed for a complete gamut of colors and a scalable process for industrial application. We demonstrate a feasible solution for producing structural colors inspired by bird feathers. We have designed core-shell nanoparticles using high-refractive index (RI) (~1.74) melanin cores and low-RI (~1.45) silica shells. The design of these nanoparticles was guided by finite-difference time-domain simulations. These nanoparticles were self-assembled using a one-pot reverse emulsion process, which resulted in bright and noniridescent supraballs. With the combination of only two ingredients, synthetic melanin and silica, we can generate a full spectrum of colors. These supraballs could be directly added to paints, plastics, and coatings and also used as ultraviolet-resistant inks or cosmetics.

  15. Selective Coloration of Melanin Nanospheres through Resonant Mie Scattering.

    Science.gov (United States)

    Cho, Soojeong; Shim, Tae Soup; Kim, Ju Hyeon; Kim, Dong-Hyun; Kim, Shin-Hyun

    2017-06-01

    Black melanin inks are prepared to selectively exhibit colors under strong light, inspired by human hair. High absorbance of melanin suppresses multiple scattering, causing resonant Mie scattering predominant. Various colors can be developed as the resonant wavelength dictated by nanosphere diameter. Therefore, the melanin inks can be used to encrypt and selectively disclose multicolor patterns for anticounterfeiting applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Thioamides as false melanin precursors. Studies in murine melanomas

    Energy Technology Data Exchange (ETDEWEB)

    Olander, K.; Larsson, B.; Dencker, L. (Department of Toxicology, University of Uppsala, Sweden)

    1983-01-01

    Melanotic melanomas show a high rate of melanin synthesis. Foreign substances that are accepted as precursors in the formation of melanin may therefore be useful in the diagnosis and therapy of malignant melanotic melanomas, if labelled with suitable radionuclides. We have earlier reported that 2-thiouracil is incorporated in melanotic melanomas, apparently as a false melanin precursor. In the present study it is shown that methimazole and 5-iodo-2-thiouracil are as well accepted as melanin precursors. 5-Iodo-2-thiouracil is of special interest, since iodine has many clinically useful radioisotopes. The chemical properties that characterize substances which are incorporated as false precursors into melanin are discussed. A free sulfur ligand of the thioamides (2-thiouracil, 5-iodo-2-thiouracil, methimazole and thiourea are all incorporated into melanin) seems to be essential and the link between these substances and the melanin. Uracil (which lacks sulfur) and 2-benzylthiouracil (where the sulfur is blocked with a benzyl group) do not attach to melanin. Our conclusion therefore is that the thioureylene structure is the smallest common molecular fragment of the false melanin precursors.

  17. Implications of melanin binding in ocular drug delivery.

    Science.gov (United States)

    Rimpelä, Anna-Kaisa; Reinisalo, Mika; Hellinen, Laura; Grazhdankin, Evgeni; Kidron, Heidi; Urtti, Arto; Del Amo, Eva M

    2017-12-13

    Pigmented ocular tissues contain melanin within the intracellular melanosomes. Drugs bind to melanin at varying extent that ranges from no binding to extensive binding. Binding may lead to drug accumulation to the pigmented tissues and prolonged drug retention in the melanin containing cells. Therefore, melanin binding is an important feature that affects ocular drug delivery and biodistribution, but this topic has not been reviewed since 1998. In this review, we present current knowledge on ocular melanin, melanosomes and binding of drugs to pigmented cells and tissues. In vitro, in vivo and in silico methods in the field were critically evaluated, because the literature in this field can be confusing if the reader does not properly understand the methodological aspects. Literature analysis includes a comprehensive table of literature data on melanin binding of drugs. Furthermore, we aimed to give some insights beyond the current literature by making a chemical structure based classification model for melanin binding of drugs and kinetic simulations that revealed significant interplay between melanin binding and drug permeability across the melanosomal and plasma membranes. Overall, more mechanistic and systematic research is needed before the impact of melanin binding on ocular drug delivery can be properly understood and predicted. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Influence of variation in melanin content on absorbance spectra of liquid skin phantoms

    CSIR Research Space (South Africa)

    Smit, Jacoba E

    2010-09-01

    Full Text Available This presentation looked at the influence of variation in melanin content on absorbance spectra of liquid skin phantoms. Reasons for studying melanin, plus skin pigments, melanocytes, melanosomes, and melanin in particular, are discussed...

  19. Effect of UV irradiation on free radicals in synthetic melanin and melanin biopolymer from Sepia officinalis – EPR examination

    Directory of Open Access Journals (Sweden)

    Zdybel Magdalena

    2015-07-01

    Full Text Available Free radicals in synthetic melanin and melanin from Sepia officinalis were studied by electron paramagnetic resonance (EPR spectroscopy. The effect of time of ultraviolet (UV irradiation on free radicals in these melanins was tested. The samples were exposed to UV during 15, 30, and 60 minutes. EPR spectra were measured with microwaves from an X-band (9.3 GHz in the range of microwave power of 2.2–70 mW. The performed EPR examinations indicate that high concentrations (~1021–1022 spin/g of o-semiquinone free radicals with g factors of 2.0039–2.0045 exist in all the tested samples. For nonirradiated samples, free radical concentration was higher in natural melanin than in synthetic melanin. UV irradiation caused the increase of free radical concentrations in synthetic melanin samples and this effect depends on the time of irradiation. The largest free radical formation in the both melanins was obtained for 60 min of UV irradiation. Free radical concentrations after the UV irradiation of melanins during 30 min were lower than during irradiation by 15 min, and probably this effect was the result of recombination of the radiatively formed free radicals. EPR lines of the tested samples broadened with increasing microwave power, so these lines were homogeneously broadened. The two types of melanins differed in the time of spin-lattice relaxation processes. Slower spin-lattice relaxation processes exist in melanin from Sepia officinalis than in synthetic melanin. UV irradiation did not change the time of spin-lattice relaxation processes in the tested melanins. The performed studies confirmed the usefulness of EPR spectroscopy in cosmetology and medicine.

  20. In vivo stepwise multi-photon activation fluorescence imaging of melanin in human skin

    Science.gov (United States)

    Lai, Zhenhua; Gu, Zetong; Abbas, Saleh; Lowe, Jared; Sierra, Heidy; Rajadhyaksha, Milind; DiMarzio, Charles

    2014-03-01

    The stepwise multi-photon activated fluorescence (SMPAF) of melanin is a low cost and reliable method of detecting melanin because the activation and excitation can be a continuous-wave (CW) mode near infrared (NIR) laser. Our previous work has demonstrated the melanin SMPAF images in sepia melanin, mouse hair, and mouse skin. In this study, we show the feasibility of using SMPAF to detect melanin in vivo. in vivo melanin SMPAF images of normal skin and benign nevus are demonstrated. SMPAF images add specificity for melanin detection than MPFM images and CRM images. Melanin SMPAF is a promising technology to enable early detection of melanoma for dermatologists.

  1. Photoinduced oxygen consumption in melanin systems. Action spectra and quantum yields for eumelanin and synthetic melanin

    Energy Technology Data Exchange (ETDEWEB)

    Sarna, T.; Sealy, R.C. (Medical Coll. of Wisconsin, Milwaukee (USA))

    1984-01-01

    Consumption of oxygen during irradiation of melanins with either visible or ultraviolet light (230 to 600 nm) was monitored using a spin-probe nitroxide-electron spin resonance spectroscopic approach. Eumelanins are moderately effective in promoting oxygen consumption; quantum yields are low for irradiation with visible light, but increase sharply with light of shorter wavelengths. The absolute quantum yield for oxygen consumption is about 0.1% for natural melanin at 320 nm. The action spectrum is similar for both natural and synthetic melanins indicating that the major chromophore responsible for oxygen consumption is the same for both kinds of material. This chromophore is not the major melanin chromophore responsible for absorption of visible light. The action spectrum also clearly differs from published action spectra for melanogenesis; however, the weak wavelength dependence for visible light is similar to that found for immediate pigment darkening. Catalase decreases the rate of oxygen consumption by 50% confirming that hydrogen peroxide is the major molecular product of oxygen reduction. The results suggest that a Type I (free radical) mechanism predominates in the oxygen consumption process.

  2. Expression of melanin and insecticidal protein from Rhodotorula ...

    African Journals Online (AJOL)

    Both the salmon/red melanin and the insecticidal producing genes of Rhodotorula glutinis was successfully expressed in Escherichia coli using plasmid pZErO-1. This work suggests that in Rhodotorula species melanin and insecticidal toxin are co-expressed and therefore possibly co-evolved. Keywords: Rhodotorula ...

  3. Protective role of Aspergillus fumigatus melanin against ultraviolet ...

    African Journals Online (AJOL)

    Melanin protects pigmented cells from physical and biological stresses which are associated with virulence in several important human pathogens, but little is known about the immune response to this ubiquitous biologic compound. Melanin content increased in Aspergillus fumigatus mycelium exposed to ultraviolet for 10 ...

  4. Effect of melanin on radiation response of CHO cells

    Energy Technology Data Exchange (ETDEWEB)

    Hopwood, L.E. (Medical Coll. of Wisconsin, Milwaukee (USA). Dept. of Radiation Oncology); Swartz, H.M. (Illinois Univ., Urbana (USA). Coll. of Medicine); Pajak, S. (Uniwersytet Jagiellonski, Krakow (Poland))

    1985-05-01

    The effect of the presence of melanin on the response of mammalian cells to ionizing radiation was investigated in a model system utilizing the ability of Chinese hamster ovary cells to incorporate melanin by endocytosis. Cells were incubated in monolayer cultures from 2 to 20 hours with melanin prepared from 'beef eye' or synthesized by air oxidation of 3,4-dihydroxyphenylalanine. For asynchronous cultures, the survival curve parameters for cells incubated with both types of melanin were indistinguishable from those of the same cells without added melanin. The radiation response to fractionated doses of 6 Gy separated by various periods did not indicate any effect of melanin on the extent or kinetics of repair of sublethal damage. Likewise, the repair of potentially lethal damage in plateau phase cultures was unaffected by the presence of melanin. Thus the explanation for the clinical radiation resistance of melanomas in the absence of a direct radiation effect might more likely be found in consideration of other factors such as the role of melanin in oxygen consumption or in differentiation.

  5. Melanin content of hamster tissues, human tissues, and various melanomas

    Energy Technology Data Exchange (ETDEWEB)

    Watts, K.P.; Fairchild, R.G.; Slatkin, D.N.; Greenberg, D.; Packer, S.; Atkins, H.L.; Hannon, S.J.

    1981-02-01

    Melanin content (percentage by weight) was determined in both pigmented and nonpigmented tissues of Syrian golden hamsters bearing Greene melanoma. Melanin content was also measured in various other melanoma models (B-16 in C57 mice, Harding-Passey in BALB/c mice, and KHDD in C3H mice) and in nine human melanomas, as well as in selected normal tissues. The purpose was to evaluate the possible efficacy of chlorpromazine, which is known to bind to melanin, as a vehicle for boron transport in neutron capture therapy. Successful therapy would depend upon selective uptake and absolute concentration of borated compounds in tumors; these parameters will in turn depend upon melanin concentration in melanomas and nonpigmented ''background'' tissues. Hamster whole eyes, hamster melanomas, and other well-pigmented animal melanomas were found to contain 0.3 to 0.8% melanin by weight, whereas human melanomas varied from 0.1 to 0.9% (average, 0.35%). Other tissues, with the exception of skin, were lower in content by a factor of greater than or equal to30. Melanin pigment was extracted from tissues, and the melanin content was determined spectrophotometrically. Measurements were found to be sensitive to the presence of other proteins. Previous procedures for isolating and quantifying melanin often neglected the importance of removing proteins and other interfering nonmelanic substances.

  6. Aspergillus fumigatus conidial melanin modulates host cytokine response.

    NARCIS (Netherlands)

    Chai, L.; Netea, M.G.; Sugui, J.; Vonk, A.G.; Sande, W.W. van de; Warris, A.; Kwon-Chung, K.J.; Kullberg, B.J.

    2010-01-01

    Melanin biopigments have been linked to fungal virulence. Aspergillus fumigatus conidia are melanised and are weakly immunogenic. We show that melanin pigments on the surface of resting Aspergillus fumigatus conidia may serve to mask pathogen-associated molecular patterns (PAMPs)-induced cytokine

  7. Temperature-enhanced synthesis of DMSO-Melanin

    Science.gov (United States)

    Piacenti-Silva, M.; Bronze-Uhle, E. S.; Paulin, J. V.; Graeff, C. F. O.

    2014-01-01

    Melanins are a class of pigmentary conjugated macromolecules found in many biological systems. Functionalization of synthetic melanin provides interesting new properties like the greater solubility of melanin synthesized in dimethyl sulfoxide, D-Melanin. In this work we have studied the influence of temperature on D-Melanin synthesis and its properties. To this end, UV-Vis, Fourier-transform infrared (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) techniques have been employed to analyze D-Melanin synthesized within the range of 25-100 °C. Our results reveal that by increasing the synthesis temperature up to 100 °C, the synthesis time can be decreased by a factor of 7 when compared to room temperature. From FTIR and 13C CP/MAS NMR analyses the increase in temperature causes a decrease in the number of carbonyl groups from carboxylic acid and from ionized carboxylic acid. The decarboxylation of D-Melanin monomers at higher temperatures shows that the use of higher synthesis temperatures influences the elimination of carbonyls present in the precursor molecules, thus facilitating the polymerization of D-Melanin.

  8. Aspergillus fumigatus conidial melanin modulates host cytokine response

    NARCIS (Netherlands)

    L.Y.A. Chai (Louis); M.G. Netea (Mihai); J. Sugui (Janyce); A.G. Vonk (Alieke); W.W.J. van de Sande (Wendy); A. Warris (Adilia); K.J. Kwon-Chung (Kyung); B. Jan Kullberg (Bart)

    2010-01-01

    textabstractMelanin biopigments have been linked to fungal virulence. Aspergillus fumigatus conidia are melanised and are weakly immunogenic. We show that melanin pigments on the surface of resting Aspergillus fumigatus conidia may serve to mask pathogen-associated molecular patterns (PAMPs)-induced

  9. Antibacterial Activity of Melanin from Cuttlefish and Squid Ink

    Directory of Open Access Journals (Sweden)

    Yuspihana Fitrial

    2017-08-01

    Full Text Available Marine environment comprises of many organism which are known to posses bioactive compound as a common means of self-defense or for the protection of eggs and embryos. Class Cephalopods (such as squidand cuttlefish are notable for their defences, such as jetting escape movements, changes in colouration, toxic venom and inking.This study aims to compare the antibacterial activity of melanin from cuttlefish ink (Sepia sp. with squid ink (Loligo sp. against E. coli. Extraction and purification studies were carried out on Sepia and Loligo melanin using a hydrochloric acid 0,5M treatment under mechanical.The melanins were obtained and further evaluated their activity by direct contact methods between melanin and E. coli in nutrient broth.Total microbes was counted by total plate count.Both inks also was tested their activity against E. coli. The results showed that melanin from cuttlefish and squid inks had inhibitory activity at concentrations of 10 mg / ml and 20 mg / mL, respectively reaching 99.99% against E. coli.The inks of both Cephalopods at the same concentration as melanin, did not show any inhibitory activity against E. coli.  The melanin of Sepia sp. have a higher antibacterial activity than the melanin of Loligo sp.

  10. Matrix assisted pulsed laser deposition of melanin thin films

    Science.gov (United States)

    Bloisi, F.; Pezzella, A.; Barra, M.; Chiarella, F.; Cassinese, A.; Vicari, L.

    2011-07-01

    Melanins constitute a very important class of organic pigments, recently emerging as a potential material for a new generation of bioinspired biocompatible electrically active devices. In this paper, we report about the deposition of synthetic melanin films starting from aqueous suspensions by matrix assisted pulsed laser evaporation (MAPLE). In particular, we demonstrate that it is possible to deposit melanin films by MAPLE even if melanin (a) is not soluble in water and (b) absorbs light from UV to IR. AFM images reveal that the film surface features are highly depending on the deposition parameters. UV-VIS and FTIR spectra show both the optical properties and the molecular structure typical of melanins are preserved.

  11. Natural melanin composites by layer-by-layer assembly

    Science.gov (United States)

    Eom, Taesik; Shim, Bong Sub

    2015-04-01

    Melanin is an electrically conductive and biocompatible material, because their conjugated backbone structures provide conducting pathways from human skin, eyes, brain, and beyond. So there is a potential of using as materials for the neural interfaces and the implantable devices. Extracted from Sepia officinalis ink, our natural melanin was uniformly dispersed in mostly polar solvents such as water and alcohols. Then, the dispersed melanin was further fabricated to nano-thin layered composites by the layer-by-layer (LBL) assembly technique. Combined with polyvinyl alcohol (PVA), the melanin nanoparticles behave as an LBL counterpart to from finely tuned nanostructured films. The LBL process can adjust the smart performances of the composites by varying the layering conditions and sandwich thickness. We further demonstrated the melanin loading degree of stacked layers, combination nanostructures, electrical properties, and biocompatibility of the resulting composites by UV-vis spectrophotometer, scanning electron microscope (SEM), multimeter, and in-vitro cell test of PC12, respectively.

  12. Melanin photosensitizes ultraviolet light (UVC) DNA damage in pigmented cells

    International Nuclear Information System (INIS)

    Huselton, C.A.; Hill, H.Z.

    1990-01-01

    Melanins, pigments of photoprotection and camouflage, are very photoreactive and can both absorb and emit active oxygen species. Nevertheless, black skinned individuals rarely develop skin cancer and melanin is assumed to act as a solar screen. Since DNA is the target for solar carcinogenesis, the effect of melanin on Ultraviolet (UV)-induced thymine lesions was examined in mouse melanoma and carcinoma cells that varied in melanin content. Cells prelabeled with 14C-dThd were irradiated with UVC; DNA was isolated, purified, degraded to bases by acid hydrolysis and analyzed by HPLC. Thymine dimers were detected in all of the extracts of irradiated cells. Melanotic and hypomelanotic but not mammary carcinoma cell DNA from irradiated cells contained hydrophilic thymine derivatives. The quantity of these damaged bases was a function of both the UVC dose and the cellular melanin content. One such derivative was identified by gas chromatography-mass spectroscopy as thymine glycol. The other appears to be derived from thymine glycol by further oxidation during acid hydrolysis of the DNA. The finding of oxidative DNA damage in melanin-containing cells suggests that melanin may be implicated in the etiology of caucasian skin cancer, particularly melanoma. Furthermore, the projected decrease in stratospheric ozone could impact in an unanticipated deleterious manner on dark-skinned individuals

  13. A Pathway Analysis of Melanin Patterning in a Hemimetabolous Insect

    Science.gov (United States)

    Liu, Jin; Lemonds, Thomas R.; Marden, James H.; Popadić, Aleksandar

    2016-01-01

    Diversity in insect pigmentation, encompassing a wide range of colors and spatial patterns, is among the most noticeable features distinguishing species, individuals, and body regions within individuals. In holometabolous species, a significant portion of such diversity can be attributed to the melanin synthesis genes, but this has not been formally assessed in more basal insect lineages. Here we provide a comprehensive analysis of how a set of melanin genes (ebony, black, aaNAT, yellow, and tan) contributes to the pigmentation pattern in a hemipteran, Oncopeltus fasciatus. For all five genes, RNA interference depletion caused alteration of black patterning in a region-specific fashion. Furthermore, the presence of distinct nonblack regions in forewings and hindwings coincides with the expression of ebony and aaNAT in these appendages. These findings suggest that the region-specific phenotypes arise from regional employment of various combinations of the melanin genes. Based on this insight, we suggest that melanin genes are used in two distinct ways: a “painting” mode, using predominantly melanin-promoting factors in areas that generally lack black coloration, and, alternatively, an “erasing” mode, using mainly melanin-suppressing factors in regions where black is the dominant pigment. Different combinations of these strategies may account for the vast diversity of melanin patterns observed in insects. PMID:26984060

  14. Melanin photosensitizes ultraviolet light (UVC) DNA damage in pigmented cells

    Energy Technology Data Exchange (ETDEWEB)

    Huselton, C.A.; Hill, H.Z. (New Jersey Medical School, Newark (USA))

    1990-01-01

    Melanins, pigments of photoprotection and camouflage, are very photoreactive and can both absorb and emit active oxygen species. Nevertheless, black skinned individuals rarely develop skin cancer and melanin is assumed to act as a solar screen. Since DNA is the target for solar carcinogenesis, the effect of melanin on Ultraviolet (UV)-induced thymine lesions was examined in mouse melanoma and carcinoma cells that varied in melanin content. Cells prelabeled with 14C-dThd were irradiated with UVC; DNA was isolated, purified, degraded to bases by acid hydrolysis and analyzed by HPLC. Thymine dimers were detected in all of the extracts of irradiated cells. Melanotic and hypomelanotic but not mammary carcinoma cell DNA from irradiated cells contained hydrophilic thymine derivatives. The quantity of these damaged bases was a function of both the UVC dose and the cellular melanin content. One such derivative was identified by gas chromatography-mass spectroscopy as thymine glycol. The other appears to be derived from thymine glycol by further oxidation during acid hydrolysis of the DNA. The finding of oxidative DNA damage in melanin-containing cells suggests that melanin may be implicated in the etiology of caucasian skin cancer, particularly melanoma. Furthermore, the projected decrease in stratospheric ozone could impact in an unanticipated deleterious manner on dark-skinned individuals.

  15. Melanin in Fonsecaea pedrosoi: a trap for oxidative radicals

    Directory of Open Access Journals (Sweden)

    de Souza Wanderley

    2010-03-01

    Full Text Available Abstract Background The pathogenic fungus Fonsecaea pedrosoi constitutively produces the pigment melanin, an important virulence factor in fungi. Melanin is incorporated in the cell wall structure and provides chemical and physical protection for the fungus. We evaluated the production of nitric oxide (NO in macrophages, the oxidative burst and the inducible nitric oxide synthase (i-NOS activity in interactions between activated murine macrophages and F. pedrosoi. Experiments were carried out with or without tricyclazole (TC treatment, a selective inhibitor of the dihydroxynaphthalene (DHN-melanin biosynthesis pathway in F. pedrosoi. The paramagnetisms of melanin and the TC-melanin were analysed by electron spin resonance. The fungal growth responses to H2O2 and to S-nitroso-N-acetylpenicillamine (SNAP, a nitric oxide donor, were also evaluated. Results Melanised F. pedrosoi cells were more resistant to both H2O2 and NO. Nitrite was not detected in the supernatant of macrophages incubated with melanised fungal cells. However, i-NOS expression was unaffected by the presence of either untreated control F. pedrosoi or TC-treated F. pedrosoi. In addition, the inhibition of the DHN-melanin pathway by TC improved the oxidative burst capability of the macrophages. Conclusion The NO-trapping ability of F. pedrosoi melanin is an important mechanism to escape the oxidative burst of macrophages.

  16. Subcellular Compartmentalization and Trafficking of the Biosynthetic Machinery for Fungal Melanin

    Directory of Open Access Journals (Sweden)

    Srijana Upadhyay

    2016-03-01

    Full Text Available Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell-wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are recruited to endosomes through a non-conventional secretory pathway. In contrast, late melanin enzymes accumulate in the cell wall. Such subcellular compartmentalization of the melanin biosynthetic machinery occurs in both A. fumigatus and A. nidulans. Thus, fungal melanin biosynthesis appears to be initiated in endosomes with exocytosis leading to melanin extracellular deposition, much like the synthesis and trafficking of mammalian melanin in endosomally derived melanosomes.

  17. Fungal melanin: what do we know about structure?

    Directory of Open Access Journals (Sweden)

    Joshua D Nosanchuk

    2015-12-01

    Full Text Available The production of melanin significantly enhances the virulence of many important human pathogenic fungi. Despite fungal melanin’s importance in human disease, as well as melanin’s contribution to the ability of fungi to survive in diverse hostile environments, the structure of melanin remains unsolved. Nevertheless, ongoing research efforts have progressively revealed several notable structural characteristics of this enigmatic pigment, which will be the focus of this review. These compositional and organizational insights could further our ability to develop novel therapeutic approaches to combat fungal disease and enhance our understanding of how melanin is inserted into the cell wall.

  18. Dual role of melanins and melanin precursors as photoprotective and phototoxic agents: inhibition of ultraviolet radiation-induced lipid peroxidation

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, S.; Jimbow, K. [Alberta Univ., Edmonton, AB (Canada). Dept. of Dermatology and Cutaneous Sciences; Thomas, P.D.; Poznansky, M.J. [Alberta Univ., Edmonton, AB (Canada). Dept. of Physiology; Allen, T.M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Pharmacology

    1995-06-01

    Ultraviolet radiation (UVR) is one of the risk factors for skin cancer and the main inducer of melanin pigmentation, the major protective mechanism of mammalian skin against radiation damage. The melanin pigments, eumelanin and pheomelanin, are likely to be important in protection against UVR, but their precursors are generally considered as phototoxic. The available data suggest DNA damage as the mechanism of phototoxicity. However, the effect of melanin precursors on membrane damage through lipid peroxidation, another important and probably more relevant (from the point-of-view of the melanosomal confinement of these molecules) mechanism of phototoxicity, is not known. As a model system for UVR-melanin-membrane interactions, we irradiated liposomes in the presence of eumelanin, pheomelanin and two of their major precursors, 5,6-dihydroxyindole (DHI) and 5-S-cysteinyldopa (SCD). The presence of the two melanin precursors substantially reduced the formation of lipid peroxidation products resulting from UVR exposure. The antioxidant activity of the melanin precursors was diminished under strong prooxidant conditions (presence of Fe{sub 3+}). These results suggest that melanin precursors may have an important role in the protection of skin against the harmful effects of UVR including photocarcinogenesis. (Author).

  19. Quantitative variation of melanins in alpaca (Lama pacos L.

    Directory of Open Access Journals (Sweden)

    Marco Antonini

    2011-07-01

    Full Text Available The amount of melanin pigments was investigated in 95 Peruvian alpaca, representative of six different fleece colours, by means of spectrophotometric assays: SpEM (Spectrophoto­metric Eumelanin, SpPM (Spectrophotometric Pheomelanin, SpASM (Spectrophotometric Alkali Soluble Melanin, and SpTM (Spectro­photometric Total Melanin. It was found that these melanin pigments were suitable for identifying three homogeneous groups, each consisting of two closely related colours. A low, an intermediate, and a high amount of SpASM, SpTM, and SpPM characterize pinkish grey and light reddish brown, brown and reddish brown, dark reddish brown and black fleeces, respectively. SpEM and SpTM provide a further split within this latter group; higher concentrations of these pigments distinguish black fleece from dark reddish brown.

  20. Melanin fluorescence spectra by step-wise three photon excitation

    Science.gov (United States)

    Lai, Zhenhua; Kerimo, Josef; DiMarzio, Charles A.

    2012-03-01

    Melanin is the characteristic chromophore of human skin with various potential biological functions. Kerimo discovered enhanced melanin fluorescence by stepwise three-photon excitation in 2011. In this article, step-wise three-photon excited fluorescence (STPEF) spectrum between 450 nm -700 nm of melanin is reported. The melanin STPEF spectrum exhibited an exponential increase with wavelength. However, there was a probability of about 33% that another kind of step-wise multi-photon excited fluorescence (SMPEF) that peaks at 525 nm, shown by previous research, could also be generated using the same process. Using an excitation source at 920 nm as opposed to 830 nm increased the potential for generating SMPEF peaks at 525 nm. The SMPEF spectrum peaks at 525 nm photo-bleached faster than STPEF spectrum.

  1. Melanin-binding drugs and ultrasonics-induced cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    McGinness, J.; Corry, P.M.; Armour, E.

    1973-01-01

    In vitro experiments with human melanoma cells indicate that ultrasonic induced killing of melanin-containing cells can be potentiated by the proper choice of temperature and drugs. These agents appear to be interacting through electron-phonon coupling in the melanins within the melanosome itself. As the mechanism of these interactions becomes clearer, it may be possible to relate these phenomena to some human syndromes and perhaps develop controlled methods to kill pigmented tumor cells.

  2. Kinetics of Melanin Polymerization during Enzymatic and Nonenzymatic Oxidation.

    Science.gov (United States)

    Mondal, Sayan; Thampi, Arya; Puranik, Mrinalini

    2018-02-22

    Melanin is an abundant biopigment in the animal kingdom, but its structure remains poorly understood. This is a substantial impediment to understanding the mechanistic origin of its observed functions. Proposed models of melanin structure include aggregates of both linear and macrocyclic units and noncovalently held monomers. Both models are broadly in agreement with current experimental data. To constrain the structural and kinetic models of melanin, experimental data of high resolution with chemical specificity accompanied by atomistic modeling are required. We have addressed this by obtaining electronic absorption, infrared, and ultraviolet resonance Raman (RR) spectra of melanin at several wavelengths of excitation that are sensitive to small changes in structure. From these experiments, we observed kinetics of the formation of different species en route to melanin polymerization. Exclusive chemical signatures of monomer 3,4-dihydroxyphenylalanine (dopa), intermediate dopachrome (DC), and early-time polymer are established through their vibrational bands at 1292, 1670, and 1616 cm -1 respectively. Direct evidence of reduced heterogeneity of melanin oligomers in tyrosinase-induced formation is provided from experimental measurements of vibrational bandwidths. Models made with density functional theory show that the linear homopolymeric structures of 5,6-dihydroxyindole can account for experimentally observed wavenumbers and broad bandwidth in Raman spectra of dopa-melanin. We capture resonance Raman (RR) signature of DC, the intermediate stabilized by the enzyme tyrosinase, for the first time in an enzyme-assisted melanization reaction using 488 nm excitation wavelength and propose that this wavelength can be used to probe reaction intermediates of melanin formation in solution.

  3. Bird Integumentary Melanins: Biosynthesis, Forms, Function and Evolution

    Directory of Open Access Journals (Sweden)

    Ismael Galván

    2016-04-01

    Full Text Available Melanins are the ubiquitous pigments distributed in nature. They are one of the main pigments responsible for colors in living cells. Birds are among the most diverse animals regarding melanin-based coloration, especially in the plumage, although they also pigment bare parts of the integument. This review is devoted to the main characteristics of bird melanins, including updated views of the formation and nature of melanin granules, whose interest has been raised in the last years for inferring the color of extinct birds and non-avian theropod dinosaurs using resistant fossil feathers. The molecular structure of the two main types of melanin, eumelanin and pheomelanin, and the environmental and genetic factors that regulate avian melanogenesis are also presented, establishing the main relationship between them. Finally, the special functions of melanin in bird feathers are also discussed, emphasizing the aspects more closely related to these animals, such as honest signaling, and the factors that may drive the evolution of pheomelanin and pheomelanin-based color traits, an issue for which birds have been pioneer study models.

  4. [Antifungal activity of melanin in clinical isolates of Candida spp].

    Science.gov (United States)

    Fuentes, Marisol; Hernández, Romané; Gordillo, Diego; Amaro, José; Falconer, Mary A; Alburquenque, Claudio; Tapia, Cecilia V

    2014-02-01

    Melanocytes are cells located in epidermis and mucous membranes that synthesize melanin and cytokines. It is known that melanin has antimicrobial activity and that melanocytes are melanized in presence of microbial molecules. To study the antifungal activity of melanin on Candida spp. The minimum inhibitory concentration (MIC) to melanin was determined in 4 Candida ATCC strains (C. albicans SC5314, C. parapsilosis 22019, C. glabrata 2001, C. krusei 6258) and 56 clinical isolates of Candida spp. (33 C. albicans, 12 C. glabrata, 3 C. famata, 3 C. krusei, 3 C. parapsilosis, 2 C. tropicalis) using a broth microdilution method. In addition, the antifungal activity of melanocytes and mice melanoma cells was tested against C. albicans. Melanin inhibited the tested isolates, including the susceptible dose-dependent and fluconazole-resistant strains; MIC range and MIC50 were 0.09-50 μg/mL and 6.25 μg/mL, respectively. Pigmented cells lysates inhibited C. albicans. Melanin is able to inhibit clinical isolates of Candida spp. Melanization could be an important protective mechanism of melanocytes.

  5. Development of gadolinium based nanoparticles having an affinity towards melanin

    Science.gov (United States)

    Morlieras, Jessica; Chezal, Jean-Michel; Miot-Noirault, Elisabeth; Roux, Amandine; Heinrich-Balard, Laurence; Cohen, Richard; Tarrit, Sébastien; Truillet, Charles; Mignot, Anna; Hachani, Roxanne; Kryza, David; Antoine, Rodolphe; Dugourd, Philippe; Perriat, Pascal; Janier, Marc; Sancey, Lucie; Lux, François; Tillement, Olivier

    2013-01-01

    Small Rigid Platforms (SRPs) are sub-5 nanometre gadolinium based nanoparticles that have been developed for multimodal imaging and theranostic applications. They are composed of a polysiloxane network surrounded by gadolinium chelates. A covalent coupling with quinoxaline derivatives has been performed. Such derivatives have proven their affinity for melanin frequently expressed in primary melanoma cases. Three different quinoxaline derivatives have been synthesised and coupled to the nanoparticles. The affinity of the grafted nanoparticles for melanin has then been shown in vitro by surface plasmon resonance on a homemade melanin grafted gold chip.Small Rigid Platforms (SRPs) are sub-5 nanometre gadolinium based nanoparticles that have been developed for multimodal imaging and theranostic applications. They are composed of a polysiloxane network surrounded by gadolinium chelates. A covalent coupling with quinoxaline derivatives has been performed. Such derivatives have proven their affinity for melanin frequently expressed in primary melanoma cases. Three different quinoxaline derivatives have been synthesised and coupled to the nanoparticles. The affinity of the grafted nanoparticles for melanin has then been shown in vitro by surface plasmon resonance on a homemade melanin grafted gold chip. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33457g

  6. Photodegradation of melanin thin films by UV lithography

    Science.gov (United States)

    Farley, C. W.; Kassu, A.; Sharma, A.

    2011-09-01

    Effect of ambient humidity on the photodegradation of melanin is investigated using an interferometric technique to fabricate gratings on thin films. A low power 355 nm diode laser is used to fabricate gratings on melanin thin films, while a 1 mW He-Ne laser is used to probe grating formation. Effects at several different UV intensities, ranging from 10 mW to 30 mW, and ambient humidities, ranging from 13% to 93%, are investigated on melanin thin films of two different thicknesses; 22 nm and 40nm. It is found that humidity has a great effect on the photodegradation of melanin. It is also found that existing gratings on melanin thin films can be enhanced by raising ambient humidity. These results have implications in the biological evolution of many mammals; as well as implications in fabrication and effective lifetime of organic electronics. The interferometric technique used shows great promise for fabricating grating to analyze photodegradation of different biomolecules under varying conditions. A simple mathematical model is developed to help explain the contribution of light intensity and ambient humidity to the photodegradation of melanin.nage.

  7. 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis inhibitors increase erythritol production in Torula corallina, and DHN-melanin inhibits erythrose reductase.

    Science.gov (United States)

    Lee, Jung-Kul; Jung, Hyung-Moo; Kim, Sang-Yong

    2003-06-01

    The yeast Torula corallina is a strong erythritol producer that is used in the industrial production of erythritol. However, melanin accumulation during culture represents a serious problem for the purification of erythritol from the fermentation broth. Melanin biosynthesis inhibitors such as 3,4-dihydroxyphenylalanine and 1,8-dihydroxynaphthalene (DHN)-melanin inhibitors were added to the T. corallina cultures. Only the DHN-melanin inhibitors showed an effect on melanin production, which suggests that the melanin formed during the culturing of T. corallina is derived from DHN. This finding was confirmed by the detection of a shunt product of the pentaketide pathway, flaviolin, and elemental analysis. Among the DHN-melanin inhibitors, tricyclazole was the most effective. Supplementation with tricyclazole enhanced the production of erythritol while significantly inhibiting the production of DHN-melanin and DHN-melanin biosynthetic enzymes, such as trihydroxynaphthalene reductase. The erythrose reductase from T. corallina was purified to homogeneity by ion-exchange and affinity chromatography. Purified erythrose reductase was significantly inhibited in vitro in a noncompetitive manner by elevated levels of DHN-melanin. In contrast, the level of erythrose reductase activity was unaffected by increasing concentrations of tricyclazole. These results suggest that supplemental tricyclazole reduces the production of DHN-melanin, which may lead to a reduction in the inhibition of erythrose reductase and a higher yield of erythritol. This is the first report to demonstrate that melanin biosynthesis inhibitors increase the production of a sugar alcohol in T. corallina.

  8. The stepwise multi-photon activation fluorescence guided ablation of melanin

    Science.gov (United States)

    Lai, Zhenhua; Gu, Zetong; DiMarzio, Charles

    2015-02-01

    Previous research has shown that the stepwise multi-photon activation fluorescence (SMPAF) of melanin, activated and excited by a continuous-wave (CW) mode near infrared (NIR) laser, is a low-cost and reliable method for detecting melanin. We have developed a device utilizing the melanin SMPAF to guide the ablation of melanin with a 975 nm CW laser. This method provides the ability of targeting individual melanin particles with micrometer resolution, and enables localized melanin ablation to be performed without collateral damage. Compared to the traditional selective photothermolysis, which uses pulsed lasers for melanin ablation, this method demonstrates higher precision and lower cost. Therefore, the SMPAF guided selective ablation of melanin is a promising tool of melanin ablation for both medical and cosmetic purposes.

  9. Melanin concentrating hormone in central hypersomnia.

    Science.gov (United States)

    Peyron, Christelle; Valentin, Françoise; Bayard, Sophie; Hanriot, Lucie; Bedetti, Christophe; Rousset, Bernard; Luppi, Pierre-Hervé; Dauvilliers, Yves

    2011-09-01

    Narcolepsy with cataplexy (NC) is a disabling disorder characterized by excessive daytime sleepiness and abnormal rapid eye movement (REM) sleep manifestations, due to a deficient hypocretin/orexin neurotransmission. Melanin concentrating hormone (MCH) neurons involved in the homeostatic regulation of REM sleep are intact. We hypothesized that an increased release of MCH in NC would be partly responsible for the abnormal REM sleep manifestations. Twenty-two untreated patients affected with central hypersomnia were included: 14 NC, six idiopathic hypersomnia with long sleep time, and two post-traumatic hypersomnia. Fourteen neurological patients without any sleep disorders were included as controls. Using radioimmunoassays, we measured hypocretin-1 and MCH levels in cerebrospinal fluid (CSF). The MCH level was slightly but significantly lower in patients with hypersomnia (98 ± 32 pg/ml) compared to controls (118 ± 20 pg/ml). After exclusion of patients affected with post-traumatic hypersomnia the difference became non-significant. We also failed to find any association between MCH level and hypocretin level, the severity of daytime sleepiness, the number of SOREMPs, the frequency of cataplexy, and the presence of hypnagogic hallucinations or sleep paralysis. This study reports the first measurement of MCH in CSF using radioimmunoassay technology. It appears to be a non-informative tool to differentiate etiologies of central hypersomnia with or without REM sleep dysregulation. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Optical properties of cells with melanin

    Science.gov (United States)

    Rohde, Barukh; Coats, Israel; Krueger, James; Gareau, Dan

    2014-02-01

    The optical properties of pigmented lesions have been studied using diffuse reflectance spectroscopy in a noninvasive configuration on optically thick samples such as skin in vivo. However, it is difficult to un-mix the effects of absorption and scattering with diffuse reflectance spectroscopy techniques due to the complex anatomical distributions of absorbing and scattering biomolecules. We present a device and technique that enables absorption and scattering measurements of tissue volumes much smaller than the optical mean-free path. Because these measurements are taken on fresh-frozen sections, they are direct measurements of the optical properties of tissue, albeit in a different hydration state than in vivo tissue. Our results on lesions from 20 patients including melanomas and nevi show the absorption spectrum of melanin in melanocytes and basal keratinocytes. Our samples consisted of fresh frozen sections that were unstained. Fitting the spectrum as an exponential decay between 500 and 1100 nm [mua = A*exp(-B*(lambda-C)) + D], we report on the fit parameters of and their variation due to biological heterogeneity as A = 4.20e4 +/- 1.57e5 [1/cm], B = 4.57e-3 +/- 1.62e-3 [1/nm], C = 210 +/- 510 [nm] , D = 613 +/- 534 [1/cm]. The variability in these results is likely due to highly heterogeneous distributions of eumelanin and pheomelanin.

  11. The protective effect of melanin against radiation. Final technical report, Oct 1975--Oct 1976

    Energy Technology Data Exchange (ETDEWEB)

    Swan, G.A.; Baldry, P.A.

    1976-10-01

    Oxidation and reduction of autoxidative dopa-melanin were studied. Reduction with neither ascorbic acid nor sodium dithionite led to any overall increase in the number of 5,6-dihydroxyindole units in the melanin polymer. The melanin was oxidised using repsectivley potassium ferricyanide and ceric sulphate solutions but in neither case was the melanin e.s.r. signal diminished. The interaction of melanin's free radicals with cupric ions was shown not to be chemical in nature. The number of bound cupric ions was determined and the value used to calculate the number of free radicals in autoxidative dopa-melanin.

  12. Melanin Transferred to Keratinocytes Resides in Nondegradative Endocytic Compartments.

    Science.gov (United States)

    Correia, Maria S; Moreiras, Hugo; Pereira, Francisco J C; Neto, Matilde V; Festas, Tiago C; Tarafder, Abul K; Ramalho, José S; Seabra, Miguel C; Barral, Duarte C

    2018-03-01

    Melanin transfer from melanocytes to keratinocytes and subsequent accumulation in the supranuclear region is a critical process in skin pigmentation and protection against UVR. We have previously proposed that the main mode of transfer between melanocytes and keratinocytes is through exo/endocytosis of the melanosome core, termed melanocore. In this study, we developed an in vitro uptake assay using melanocores secreted by melanocytes. We show that the uptake of melanocores, but not melanosomes, by keratinocytes is protease-activated receptor-2-dependent. Furthermore, we found that the silencing of the early endocytic regulator Rab5b, but not the late endocytic regulators Rab7a or Rab9a, significantly impairs melanocore uptake by keratinocytes. After uptake, we observed that melanin accumulates in compartments that are positive for both early and late endocytic markers. We found that melanin does not localize to either highly degradative or acidic organelles, as assessed by LysoTracker and DQ-BSA staining, despite the abundance of these types of organelles within keratinocytes. Therefore, we propose that melanocore uptake leads to storage of melanin within keratinocytes in hybrid endocytic compartments that are not highly acidic or degradative. By avoiding lysosomal degradation, these specialized endosomes may allow melanin to persist within keratinocytes for long periods. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Genetic validation and spectroscopic detailing of DHN-melanin extracted from an environmental fungus

    Directory of Open Access Journals (Sweden)

    Nitya Meenakshi Raman

    2017-12-01

    Full Text Available Accurate characterization of melanin using analytical methodologies has proved to be difficult due to its heterogeneity, insolubility in wide pH and broad range of solvents. The present study was undertaken to characterize melanin extracted from an environmental Aspergillus fumigatus AFGRD105 by studying its genes, chemical properties and spectral data. A gene based approach to confirm the type of melanin carried out indicated the extracted melanin to be of the dihydroxynaphthalene type. On comparison with synthetic melanin, UV–Vis and IR spectra of the extracted melanin revealed characteristic peaks that can be further used for confirmation of DHN-melanin extracted from any source. Solid state 13C NMR spectroscopy established the presence of the hydroxyl-naphthalene moiety and validated the results obtained by genetic analysis. The correct assignment of the observed spectral frequency characteristic of functional groups can be further adapted in future works that deal with binding capacities and biomolecule systems involving melanin.

  14. Genetic validation and spectroscopic detailing of DHN-melanin extracted from an environmental fungus.

    Science.gov (United States)

    Raman, Nitya Meenakshi; Ramasamy, Suganthi

    2017-12-01

    Accurate characterization of melanin using analytical methodologies has proved to be difficult due to its heterogeneity, insolubility in wide pH and broad range of solvents. The present study was undertaken to characterize melanin extracted from an environmental Aspergillus fumigatus AFGRD105 by studying its genes, chemical properties and spectral data. A gene based approach to confirm the type of melanin carried out indicated the extracted melanin to be of the dihydroxynaphthalene type. On comparison with synthetic melanin, UV-Vis and IR spectra of the extracted melanin revealed characteristic peaks that can be further used for confirmation of DHN-melanin extracted from any source. Solid state 13 C NMR spectroscopy established the presence of the hydroxyl-naphthalene moiety and validated the results obtained by genetic analysis. The correct assignment of the observed spectral frequency characteristic of functional groups can be further adapted in future works that deal with binding capacities and biomolecule systems involving melanin.

  15. Inhibition of two stages of melanin synthesis by sesamol, sesamin and sesamolin

    Directory of Open Access Journals (Sweden)

    Montra Srisayam

    2017-10-01

    Conclusions: Three sesame lignans prevent melanin synthesis through 2 stages: (a by blocking melanin-induction and (b by interrupting melanogenic enzyme production. This study provides evidence that sesamol, sesamin and sesamolin are potential for antimelanogenesis agents.

  16. MMS 1001 inhibits melanin synthesis via ERK activation.

    Science.gov (United States)

    Lee, Hyun-E; Song, Jiho; Kim, Su Yeon; Park, Kyoung-Chan; Min, Kyung Hoon; Kim, Dong-Seok

    2013-03-01

    Melanin plays major a role in pigmentation of hair, eyes, and skin in mammals. In this study, the inhibitory effects of MMS 1001 on alpha-MSH-stimulated melanogenesis were investigated in B16F10 melanoma cells. MMS 1001 did not show cytotoxic effects up to 10 microM. Melanin content and intracellular tyrosinase activity were inhibited by MMS 1001 treatment in a dose-dependent manner. In Western blot analysis, MITF expression was decreased by MMS 1001. In addition, tyrosinase expressions were also reduced after MMS 1001 treatment. Further results showed that the phosphorylation of ERK was induced by MMS 1001. Moreover, a specific MEK inhibitor, PD98059, abrogated the inhibitory effects of MMS 1001 on melanin production and tyrosinase expression. These results indicate that the hypopigmentary effects of MMS 1001 resulted from the inhibition of MITF and tyrosinase expression via phosphorylation of ERK. Thus, MMS 1001 could be developed as a new effective skin-whitening agent.

  17. Melanin determination by high performance liquid chromatography (HPLC) for K. marxianus

    Science.gov (United States)

    Ultraviolet light (UV) mutated K. marxianus was found to turn dark brown during a growth assay. This brown color was hypothesized to be melanin overproduction influenced by the UV exposure. Cell cultures were oxidized and HPLC analyzed to determine melanin concentrations. The resulting melanin con...

  18. Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies

    Directory of Open Access Journals (Sweden)

    Néstor Correa

    2017-07-01

    Full Text Available Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans (n = 4 and C. gattii (n = 4 were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range: 13.7/(7.8–15.6 and 19.5/(15.6–31.2 μg/mL, respectively, for human melanin; 273.4/(125–>500 and 367.2/(125.5–>500 μg/mL for C. neoformans melanin and 125/(62.5–250 and 156.2/(62–250 μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal

  19. Genetic monitoring of irradiated Drosophila populations treated with antimutagen melanine

    International Nuclear Information System (INIS)

    Mosseh, I.B.; Savchenko, V.K.; Lyakh, I.P.

    1986-01-01

    It was shown that viability of irradiated Drosophila is, on an average, lower than in intact populations. The fertility first decreases then increases exceeding the control level. Melanine added to the diet increases fertility and viability of both exposed and intact Drosophila populations

  20. Uncovering of melanin fluorescence in human skin tissue

    Science.gov (United States)

    Scholz, Matthias; Stankovic, Goran; Seewald, Gunter; Leupold, Dieter

    2007-07-01

    Due to its extremely low fluorescence quantum yield, in the conventionally (one-photon) excited autofluorescence of skin tissue, melanin fluorescence is masked by several other endogenous and possibly also exogenous fluorophores (e.g. NADH, FAD, Porphyrins). A first step to enhance the melanin contribution had been realized by two-photon fs-pulse excitation in the red/near IR, based on the fact that melanin can be excited by stepwise two-photon absorption, whereas all other fluorophores in this spectral region allow only simultaneous two-photon excitation. Now, the next and decisive step has been realized: Using an extremely sensitive detection system, for the first time twophoton fluorescence of skin tissue excited with pulses in the ns-range could be measured. The motivation for this step was based on the fact that the population density of the fluorescent level resulting from a stepwise excitation has a different dependence of the pulse duration than that from a simultaneous excitation (Δt2 vs. Δt). Due to this strong discrimination between the fluorophores, practically pure melanin fluorescence can be obtained. Examples for in-vivo, ex-vivo as well as paraffin embedded skin tissue will be shown. The content of information with respect to early diagnosis of skin deseases will be discussed.

  1. Modelling and verification of melanin concentration on human skin type

    CSIR Research Space (South Africa)

    Karsten, AE

    2012-03-01

    Full Text Available Lasers are used in the minimalistic or noninvasive diagnosis and treatment of skin disorders. Less laser light reaches the deeper skin layers in dark skin types, due to its higher epidermal melanin concentration compared with lighter skin. Laser...

  2. Structural, electrical, electronic and optical properties of melanin films

    Science.gov (United States)

    Abbas, M.; D'Amico, F.; Morresi, L.; Pinto, N.; Ficcadenti, M.; Natali, R.; Ottaviano, L.; Passacantando, M.; Cuccioloni, M.; Angeletti, M.; Gunnella, R.

    2009-03-01

    We present thick, uniform and rather flat melanin films obtained using spray deposition. The morphology of the films was investigated using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Temperature-dependent electrical resistance of melanin thin films evidenced a semiconductor-like character and a hysteretic behavior linked to an irreversible process of water molecule desorption from the melanin film. X-ray Photoelectron Spectroscopy (XPS) was carried out to analyze the role of the functional groups in the primary and secondary structure of the macromolecule, showing that the contribution of the 5,6-dihydroxyindole-2-carboxylic acid (DHICA) subunit to the molecule is about 35%. Comparison of the optical absorption of the thick (800nm) and thin (80nm) films showed a spectral change when the thickness increases. From in vacuum photoconductivity (PC) measured at controlled temperatures, we suggest that the melanin films exhibit a possible charge transport mechanism by means of delocalized π states along the stacked planar secondary structure.

  3. Ions doped melanin nanoparticle as a multiple imaging agent.

    Science.gov (United States)

    Ha, Shin-Woo; Cho, Hee-Sang; Yoon, Young Il; Jang, Moon-Sun; Hong, Kwan Soo; Hui, Emmanuel; Lee, Jung Hee; Yoon, Tae-Jong

    2017-10-10

    Multimodal nanomaterials are useful for providing enhanced diagnostic information simultaneously for a variety of in vivo imaging methods. According to our research findings, these multimodal nanomaterials offer promising applications for cancer therapy. Melanin nanoparticles can be used as a platform imaging material and they can be simply produced by complexation with various imaging active ions. They are capable of specifically targeting epidermal growth factor receptor (EGFR)-expressing cancer cells by being anchored with a specific antibody. Ion-doped melanin nanoparticles were found to have high bioavailability with long-term stability in solution, without any cytotoxicity in both in vitro and in vivo systems. By combining different imaging modalities with melanin particles, we can use the complexes to obtain faster diagnoses by computed tomography deep-body imaging and greater detailed pathological diagnostic information by magnetic resonance imaging. The ion-doped melanin nanoparticles also have applications for radio-diagnostic treatment and radio imaging-guided surgery, warranting further proof of concept experimental.

  4. Diversion of the melanin synthetic pathway by dopamine product

    African Journals Online (AJOL)

    Differences in the ratio of melanin pigments create wide variations in human skin color, ranging from light to dark skin color. Thus, when the eumelanin to pheomelanin ratio is higher the skin of an individual becomes darker. To lighten skin, dopaminoquinone has to be diverted towards the production of pheomelanin by ...

  5. Predicting human epidermal melanin concentrations for different skin tones

    CSIR Research Space (South Africa)

    Smit, Jacoba E

    2011-07-01

    Full Text Available from the Realistic Skin Model (RSM) part of the ASAP® software from Breault Research. Skin-like phantoms were prepared by adding Intralipid (20% fat emulsion) to samples of increasing melanin concentration at pH ~ 7. UV-VIS transmittance spectra...

  6. Red blood cell membrane-camouflaged melanin nanoparticles for enhanced photothermal therapy.

    Science.gov (United States)

    Jiang, Qin; Luo, Zimiao; Men, Yongzhi; Yang, Peng; Peng, Haibao; Guo, Ranran; Tian, Ye; Pang, Zhiqing; Yang, Wuli

    2017-10-01

    Photothermal therapy (PTT) has represented a promising noninvasive approach for cancer treatment in recent years. However, there still remain challenges in developing non-toxic and biodegradable biomaterials with high photothermal efficiency in vivo. Herein, we explored natural melanin nanoparticles extracted from living cuttlefish as effective photothermal agents and developed red blood cell (RBC) membrane-camouflaged melanin (Melanin@RBC) nanoparticles as a platform for in vivo antitumor PTT. The as-obtained natural melanin nanoparticles demonstrated strong absorption at NIR region, higher photothermal conversion efficiency (∼40%) than synthesized melanin-like polydopamine nanoparticles (∼29%), as well as favorable biocompatibility and biodegradability. It was shown that RBC membrane coating on melanin nanoparticles retained their excellent photothermal property, enhanced their blood retention and effectively improved their accumulation at tumor sites. With the guidance of their inherited photoacoustic imaging capability, optimal accumulation of Melanin@RBC at tumors was achieved around 4 h post intravenous injection. Upon irradiation by an 808-nm laser, the developed Melanin@RBC nanoparticles exhibited significantly higher PTT efficacy than that of bare melanin nanoparticles in A549 tumor-bearing mice. Given that both melanin nanoparticles and RBC membrane are native biomaterials, the developed Melanin@RBC platform could have great potential in clinics for anticancer PTT. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Decolorization of synthetic melanins by crude laccases of Lentinus polychrous Lév.

    Science.gov (United States)

    Khammuang, Saranyu; Sarnthima, Rakrudee

    2013-01-01

    Melanins are complex natural pigments that darken the skin and are difficult to degrade. This study evaluated synthetic melanin decolorization by the crude laccase from fungus Lentinus polychrous in the absence and presence of selected redox mediators. The greatest melanin decolorization activity was 87 % at pH 6.5 within 3 h in the presence of 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS), whereas only about 22 % melanin decolorized at pH 5.0 in case of no mediator. The optimum temperatures for melanin decolorization in the absence and presence of ABTS were 55 and 35°C, respectively. Using a natural redox mediator, 1.0 mmol/L vanillin leads to 45 % melanin decolorization. Our results suggest the possibility of applying vanillin for L. polychrous laccase-catalyzed decolorization of melanin.

  8. Scavenging or Quenching Effect of Melanin on Superoxide Anion and Singlet Oxygen

    Science.gov (United States)

    Tada, Mika; Kohno, Masahiro; Niwano, Yoshimi

    2010-01-01

    Although photoprotective properties of skin melanin have been well documented, a few studies on the effect of melanin on reactive oxygen species (ROS) generated by ultraviolet (UV) irradiation have been reported. To study the interaction of melanin with ROS, scavenging or quenching effect of melanin on O2•− and 1O2 was examined by electron spin resonance (ESR)-spin trapping methods and a spectrophotometric method, respectively. Melanin potently interacted with O2•− generated in a hypoxanthine (HPX)-xanthine oxidase (XOD) reaction, and with 1O2 generated from a peroxidase, H2O2, and halide system. In the HPX-XOD reaction, it was proved that melanin doses not interfere with the enzyme reaction. It is confirmed that one of the mechanisms by which melanin protects UV-induced skin damage is likely scavenging or quenching activity against ROS such as O2•− and 1O2. PMID:20490317

  9. Melanin: spin behaviour and implications for bioelectronic devices (Presentation Recording)

    Science.gov (United States)

    Meredith, Paul; Sheliakina, Margarita; Mostert, Bernard

    2015-10-01

    The melanins are a broad class of pigmentary macromolecules found through nature that perform a wide range of functions including photo-protection [1]. The most common melanin - the brown, black pigment eumelanin, has been much studied because of its role in melanoma and also for its functional material properties [2]. Synthetic eumelanin has been shown to be photoconductive in the solid state and also possess a water content dependent dark conductivity [3]. It is now well established that these electrical properties arise from hybrid ionic-electronic behaviour, leading to the proposition that melanins could be model biocompatible systems for ion-to-electron transduction in bioelectronics. In my talk, I will discuss the basic science behind these bioelectronics properties - electrical and optical. In this context I will also describe recent electron paramagnetic spin studies which isolate the role of the various chemical moieties responsible for the hybrid ionic-electronic behaviour. I will also highlight preliminary results on prototype melanin-based bioelectronics devices and discuss possible architectures to realise elements such as solid-state switches and transducers. [1] "The physical and chemical properties of eumelanin", P. Meredith and T. Sarna, Pigment Cell Research, 19(6), pp572-594 (2006). [2] "Electronic and optoelectronic materials and devices inspired by nature", P Meredith, C.J. Bettinger, M. Irimia-Vladu, A.B. Mostert and P.E. Schwenn, Reports on Progress in Physics, 76, 034501 (2013). [3] "Is melanin a semiconductor: humidity induced self doping and the electrical conductivity of a biopolymer", A.B. Mostert, B.J. Powell, F.L. Pratt, G.R. Hanson, T. Sarna, I.R. Gentle and P. Meredith, Proceedings of the National Academy of Sciences of the USA, 109(23), 8943-8947 (2012).

  10. The effect of melanin on the bystander effect in human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Mosse, I. [Institute of Genetics and Cytology of the National Academy of Sciences, Academicheskaya Str. 27, Minsk (Belarus)]. E-mail: i.mosse@igc.bas-net.by; Marozik, P. [Institute of Genetics and Cytology of the National Academy of Sciences, Academicheskaya Str. 27, Minsk (Belarus); Radiation and Environmental Science Centre, DIT, Dublin 8 (Ireland); Seymour, C. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont. (Canada); Mothersill, C. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont. (Canada)

    2006-05-11

    The influence of melanin on radiation-induced bystander effects has been studied. Melanin is known to be a natural substance with proved radioprotective properties in different organisms and cell lines. It is non-toxic and is effective against acute and chronic irradiation. The lower the radiation dose, the higher the relative impact of melanin protection. In this study influence of melanin on human keratinocytes (HPV-G cells) has been studied using the colony-forming assay. We have shown that bystander donor medium from 0.5 Gy irradiated cells when transferred to unirradiated cells, caused almost the same effect as direct irradiation. Melanin increased the colony-forming ability of bystander recipient cells when it was added into culture medium before irradiation. The effect of melanin added after irradiation was to produce less protection in both the directly irradiated and bystander medium treated groups. The absorption spectrum of the filtered medium is identical to one of the intact culture medium showing that melanin was not present in filtered medium. Thus, it cannot protect recipient cells but reduces the amount of the bystander effect. It is concluded that melanin added before irradiation effectively decreased the radiation dose. The reduction of the impact of the bystander signal on recipient cells when melanin was added to the donor medium after harvest but before filtration, may mean that the bystander signal has a physical component as melanin can absorb all types of physical energy.

  11. Isolation and characterization of melanin pigment from yesso scallop Patinopecten yessoensis

    Science.gov (United States)

    Sun, Xiujun; Wu, Biao; Zhou, Liqing; Liu, Zhihong; Dong, Yinghui; Yang, Aiguo

    2017-04-01

    Melanin is one of the essential compounds in the pigments of molluscan shells. However, the effects of melanin on color variations in molluscs are largely unknown. Our previous study suggests that Yesso scallop Patinopecten yessoensis might contain melanin pigment in the dark brown shell. We therefore isolated melanin from the pigmented shells using hydrochloric acid method, and characterized the types of melanin pigments by spectrophotometry. The purified melanin, which was verified by spectrophotometry scanning and HPLC analysis, showed the typical characteristics of melanin absorption spectra and HPLC chromatograms. The contents of pheomelanin and eumelanin in pigmented shells, which were determined by the linear standard curve of melanin at 405 nm and 350 nm absorbance, were 48.23 ± 1.350 and 157.65 ± 5.905 mg, respectively. The present results indicate that the brown-pigmented shells of scallops comprise approximately 76.6% of eumelanin and 23.4% of pheomelanin, which supports the presence of eumelanin-rich pigment in scallop shells. Therefore, the combination of hydrochloric acid extraction and spectrophotometric quantification is a rapid and efficient method to isolate and quantify melanin in shells. This will facilitate the melanin studies related to shell color polymorphism and the selective breeding of bivalves with different shell colors.

  12. Melanin and Melanin-Related Polymers as Materials with Biomedical and Biotechnological Applications-Cuttlefish Ink and Mussel Foot Proteins as Inspired Biomolecules.

    Science.gov (United States)

    Solano, Francisco

    2017-07-18

    The huge development of bioengineering during the last years has boosted the search for new bioinspired materials, with tunable chemical, mechanical, and optoelectronic properties for the design of semiconductors, batteries, biosensors, imaging and therapy probes, adhesive hydrogels, tissue restoration, photoprotectors, etc. These new materials should complement or replace metallic or organic polymers that cause cytotoxicity and some adverse health effects. One of the most interesting biomaterials is melanin and synthetic melanin-related molecules. Melanin has a controversial molecular structure, dependent on the conditions of polymerization, and therefore tunable. It is found in animal hair and skin, although one of the common sources is cuttlefish (Sepia officinalis) ink. On the other hand, mussels synthesize adhesive proteins to anchor these marine animals to wet surfaces. Both melanin and mussel foot proteins contain a high number of catecholic residues, and their properties are related to these groups. Dopamine (DA) can easily polymerize to get polydopamine melanin (PDAM), that somehow shares properties with melanin and mussel proteins. Furthermore, PDAM can easily be conjugated with other components. This review accounts for the main aspects of melanin, as well as DA-based melanin-like materials, related to their biomedical and biotechnological applications.

  13. Melanin and Melanin-Related Polymers as Materials with Biomedical and Biotechnological Applications—Cuttlefish Ink and Mussel Foot Proteins as Inspired Biomolecules

    Directory of Open Access Journals (Sweden)

    Francisco Solano

    2017-07-01

    Full Text Available The huge development of bioengineering during the last years has boosted the search for new bioinspired materials, with tunable chemical, mechanical, and optoelectronic properties for the design of semiconductors, batteries, biosensors, imaging and therapy probes, adhesive hydrogels, tissue restoration, photoprotectors, etc. These new materials should complement or replace metallic or organic polymers that cause cytotoxicity and some adverse health effects. One of the most interesting biomaterials is melanin and synthetic melanin-related molecules. Melanin has a controversial molecular structure, dependent on the conditions of polymerization, and therefore tunable. It is found in animal hair and skin, although one of the common sources is cuttlefish (Sepia officinalis ink. On the other hand, mussels synthesize adhesive proteins to anchor these marine animals to wet surfaces. Both melanin and mussel foot proteins contain a high number of catecholic residues, and their properties are related to these groups. Dopamine (DA can easily polymerize to get polydopamine melanin (PDAM, that somehow shares properties with melanin and mussel proteins. Furthermore, PDAM can easily be conjugated with other components. This review accounts for the main aspects of melanin, as well as DA-based melanin-like materials, related to their biomedical and biotechnological applications.

  14. Structure and Function of Iron-Loaded Synthetic Melanin

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yiwen; Xie, Yijun; Wang, Zhao; Zang, Nanzhi; Carniato, Fabio; Huang, Yuran; Andolina, Christopher M.; Parent, Lucas R.; Ditri, Treffly B.; Walter, Eric D.; Botta, Mauro; Rinehart, Jeffrey D.; Gianneschi, Nathan C.

    2016-11-22

    We describe a synthetic method for increasing and controlling the iron loading of synthetic melanin nanoparticles and use the resulting materials to perform a systematic quantitative investigation on their structure- property relationship. A comprehensive analysis by magnetometry, electron paramagnetic resonance, and nuclear magnetic relaxation dispersion reveals the complexities of their magnetic behavior and how these intraparticle magnetic interactions manifest in useful material properties such as their performance as MRI contrast agents. This analysis allows predictions of the optimal iron loading through a quantitative modeling of antiferromagnetic coupling that arises from proximal iron ions. This study provides a detailed understanding of this complex class of synthetic biomaterials and gives insight into interactions and structures prevalent in naturally occurring melanins.

  15. Molecular preservation of the pigment melanin in fossil melanosomes.

    Science.gov (United States)

    Lindgren, Johan; Uvdal, Per; Sjövall, Peter; Nilsson, Dan E; Engdahl, Anders; Schultz, Bo Pagh; Thiel, Volker

    2012-05-08

    Fossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this fundamental difference in interpretation is crucial: if endogenous then the fossil microbodies would represent a significant advancement in the fields of palaeontology and evolutionary biology given, for example, the possibility to reconstruct integumentary colours and plumage colour patterns. It has previously been shown that certain trace elements occur in fossils as organometallic compounds, and hence may be used as biomarkers for melanin pigments. Here we expand this knowledge by demonstrating the presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark.

  16. Snapshot RGB mapping of skin melanin and hemoglobin

    Science.gov (United States)

    Spigulis, Janis; Oshina, Ilze

    2015-05-01

    The concept of snapshot red-green-blue (RGB) multispectral imaging was applied for skin chromophore mapping. Three monochromatic spectral images have been extracted from a single RGB image dataset at simultaneous illumination of skin by 473-, 532-, and 659-nm laser lines. The spectral images were further transformed into distribution maps of skin melanin, oxyhemoglobin, and deoxyhemoglobin, related to pigmented and vascular skin malformations. The performance and clinical potential of the proposed technique are discussed.

  17. Flavonoids and Melanins: A Common Strategy across Two Kingdoms

    OpenAIRE

    Carletti, Giorgia; Nervo, Giuseppe; Cattivelli, Luigi

    2014-01-01

    Ultraviolet (UV) radiations alter a number of metabolic functions in vivant. They produce damages to lipids, nucleic acids and proteins, generating reactive oxygen species such as singlet oxygen (O2), hydroxyl radical (HO) and superoxide anion (O2 -). Plants and animals, after their water emersion, have developed biochemical mechanisms to protect themselves from that environmental threat through a common strategy. Melanins in animals and flavonoids in plants are antioxidant pigments acting as...

  18. Madecassoside Inhibits Melanin Synthesis by Blocking Ultraviolet-Induced Inflammation

    OpenAIRE

    Eunsun Jung; Jung-A Lee; Seoungwoo Shin; Kyung-Baeg Roh; Jang-Hyun Kim; Deokhoon Park

    2013-01-01

    Madecassoside (MA), a pentacyclic triterpene isolated from Centella asitica (L.), is used as a therapeutic agent in wound healing and also as an anti-inflammatory and anti-aging agent. However, the involvement of MA in skin-pigmentation has not been reported. This study was conducted to investigate the effects of MA on ultraviolet (UV)-induced melanogenesis and mechanisms in a co-culture system of keratinocytes and melanocytes. MA significantly inhibited UVR-induced melanin synthesis and mel...

  19. Melanin-based colour polymorphism responding to climate change.

    Science.gov (United States)

    Roulin, Alexandre

    2014-11-01

    Climate warming leads to a decrease in biodiversity. Organisms can deal with the new prevailing environmental conditions by one of two main routes, namely evolving new genetic adaptations or through phenotypic plasticity to modify behaviour and physiology. Melanin-based colouration has important functions in animals including a role in camouflage and thermoregulation, protection against UV-radiation and pathogens and, furthermore, genes involved in melanogenesis can pleiotropically regulate behaviour and physiology. In this article, I review the current evidence that differently coloured individuals are differentially sensitive to climate change. Predicting which of dark or pale colour variants (or morphs) will be more penalized by climate change will depend on the adaptive function of melanism in each species as well as how the degree of colouration covaries with behaviour and physiology. For instance, because climate change leads to a rise in temperature and UV-radiation and dark colouration plays a role in UV-protection, dark individuals may be less affected from global warming, if this phenomenon implies more solar radiation particularly in habitats of pale individuals. In contrast, as desertification increases, pale colouration may expand in those regions, whereas dark colourations may expand in regions where humidity is predicted to increase. Dark colouration may be also indirectly selected by climate warming because genes involved in the production of melanin pigments confer resistance to a number of stressful factors including those associated with climate warming. Furthermore, darker melanic individuals are commonly more aggressive than paler conspecifics, and hence they may better cope with competitive interactions due to invading species that expand their range in northern latitudes and at higher altitudes. To conclude, melanin may be a major component involved in adaptation to climate warming, and hence in animal populations melanin-based colouration is

  20. Comparative EPR studies of free radicals in melanin synthesized by Bacillus weihenstephanensis soil strains

    Science.gov (United States)

    Zdybel, Magdalena; Pilawa, Barbara; Drewnowska, Justyna M.; Swiecicka, Izabela

    2017-07-01

    EPR spectroscopy was used to examine the properties of and free radical concentrations in atypical water-soluble melanin-like pigments from Bacillus weihenstephanensis strains. The same EPR spectral shape was observed in bacterial melanins as in eumelanin. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR lines indicated slow spin-lattice relaxation processes in the samples. Strong dipolar interactions characterized the tested melanin samples. Higher free radical concentrations were found in bacterial melanin than in synthetic melanin. The free radical concentrations in melanin from B. weihenstephanensis increased in the following order: strain JAS 81/4 < JAS 83/3 < JAS 86/1 < JAS 39/1.

  1. Optimization of culture medium for production of melanin by Auricularia auricula

    Directory of Open Access Journals (Sweden)

    Yu ZOU

    Full Text Available Abstract Melanin is a natural high molecular weight pigment with the huge application value and development potential in food industry. In the present study, medium composition for melanin production by fungus Auricularia auricula was investigated. Wheat bran extract, l-tyrosine, and CuSO4 were determined to optimize medium composition by response surface methodology with Box–Behnken design. Results indicated that the optimal medium composition was 26.80% (v/v wheat bran extract, 1.59 g/L l-tyrosine, and 0.11 g/L CuSO4, and the maximum melanin yield was 519.54 mg/L. Melanin production through A. auricula fermentation avoided expensive enzymatic or complicated chemical methods for melanin extraction from tissues of plant or animal, which had the huge application value and development potential for efficient production of melanin.

  2. Role of semiconductivity and ion transport in the electrical conduction of melanin

    Science.gov (United States)

    Mostert, Albertus B.; Powell, Benjamin J.; Pratt, Francis L.; Hanson, Graeme R.; Sarna, Tadeusz; Gentle, Ian R.; Meredith, Paul

    2012-01-01

    Melanins are pigmentary macromolecules found throughout the biosphere that, in the 1970s, were discovered to conduct electricity and display bistable switching. Since then, it has been widely believed that melanins are naturally occurring amorphous organic semiconductors. Here, we report electrical conductivity, muon spin relaxation, and electron paramagnetic resonance measurements of melanin as the environmental humidity is varied. We show that hydration of melanin shifts the comproportionation equilibrium so as to dope electrons and protons into the system. This equilibrium defines the relative proportions of hydroxyquinone, semiquinone, and quinone species in the macromolecule. As such, the mechanism explains why melanin at neutral pH only conducts when “wet” and suggests that both carriers play a role in the conductivity. Understanding that melanin is an electronic-ionic hybrid conductor rather than an amorphous organic semiconductor opens exciting possibilities for bioelectronic applications such as ion-to-electron transduction given its biocompatibility. PMID:22615355

  3. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine

    OpenAIRE

    Almeida-Paes, Rodrigo; Figueiredo-Carvalho, Maria Helena Galdino; Brito-Santos, F?bio; Almeida-Silva, Fernando; Oliveira, Manoel Marques Evangelista; Zancop?-Oliveira, Rosely Maria

    2016-01-01

    Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensi...

  4. Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi.

    Science.gov (United States)

    Dadachova, Ekaterina; Bryan, Ruth A; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D; Aisen, Philip; Nosanchuk, Joshua D; Casadevall, Arturo

    2007-05-23

    Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melanin is beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidis and Cryptococcus neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of (14)C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized Cladosporium sphaerospermum cells under limited nutrients conditions. Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization.

  5. Effect of Purified Mushroom Tyrosinase on Melanin Content and Melanogenic Protein Expression

    OpenAIRE

    Zaidi, Kamal Uddin; Ali, Sharique A.; Ali, Ayesha S.

    2016-01-01

    In mammalian melanocytes, melanosome is a highly specialized organelle where melanin is synthesized. Melanin synthesis is controlled by tyrosinase, the vital enzyme in melanogenic pathway. The present investigation is based on an effect of purified mushroom tyrosinase of Agaricus bisporus on B16F10 melanocytes for the melanin production via blocking pigment cell machinery. Using B16F10 melanocytes showed that the stimulation of melanogenesis by purified tyrosinase is due to increased tyrosina...

  6. Electron spin resonance of melanin from hair. Effects of temperature, pH and light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, R.; Perbet, G. (Clermont-Ferrand-2 Univ., 63 - Aubiere (France)); Deflandre, A.; Lang, G. (Centre de Recherches de la Societe L' Oreal, Aulnay Sous Bois (France) Dept. de Chimie Generale)

    1983-08-01

    The variation with temperature, pH and light of the ESR signal of hydrated melanin powders from Japanese black hair has been studied. An explanation of the results is proposed on the basis of quinhydrone type complexes and of acid-base equilibria of melanin and its semiquinone radicals. During exposure to light of wavelengths 254-600 nm, both stable and unstable radicals have been observed. The action spectrum for the formation of stable melanin radicals has been determined.

  7. Ovarian Sex Cord-stromal Tumors With Melanin Pigment: Report of a Previously Undescribed Phenomenon.

    Science.gov (United States)

    Taylor, Jennifer; McCluggage, W Glenn

    2017-11-14

    We report 2 ovarian sex cord-stromal tumors, a luteinized adult granulosa cell tumor and a cellular fibroma, with melanin pigment. These occurred in 44 and 61-yr-old patients, respectively. As far as we are aware, melanin pigment has not been described previously in an ovarian sex cord-stromal tumor, although it has been reported in a testicular Sertoli cell tumor. We review ovarian neoplasms containing melanin pigment.

  8. Non-contact assessment of melanin distribution via multispectral temporal illumination coding

    Science.gov (United States)

    Amelard, Robert; Scharfenberger, Christian; Wong, Alexander; Clausi, David A.

    2015-03-01

    Melanin is a pigment that is highly absorptive in the UV and visible electromagnetic spectra. It is responsible for perceived skin tone, and protects against harmful UV effects. Abnormal melanin distribution is often an indicator for melanoma. We propose a novel approach for non-contact melanin distribution via multispectral temporal illumination coding to estimate the two-dimensional melanin distribution based on its absorptive characteristics. In the proposed system, a novel multispectral, cross-polarized, temporally-coded illumination sequence is synchronized with a camera to measure reflectance under both multispectral and ambient illumination. This allows us to eliminate the ambient illumination contribution from the acquired reflectance measurements, and also to determine the melanin distribution in an observed region based on the spectral properties of melanin using the Beer-Lambert law. Using this information, melanin distribution maps can be generated for objective, quantitative assessment of skin type of individuals. We show that the melanin distribution map correctly identifies areas with high melanin densities (e.g., nevi).

  9. The Analgesic Acetaminophen and the Antipsychotic Clozapine Can Each Redox-Cycle with Melanin.

    Science.gov (United States)

    Temoçin, Zülfikar; Kim, Eunkyoung; Li, Jinyang; Panzella, Lucia; Alfieri, Maria Laura; Napolitano, Alessandra; Kelly, Deanna L; Bentley, William E; Payne, Gregory F

    2017-12-20

    Melanins are ubiquitous but their complexity and insolubility has hindered characterization of their structures and functions. We are developing electrochemical reverse engineering methodologies that focus on properties and especially on redox properties. Previous studies have shown that melanins (i) are redox-active and can rapidly and repeatedly exchange electrons with diffusible oxidants and reductants, and (ii) have redox potentials in midregion of the physiological range. These properties suggest the functional activities of melanins will depend on their redox context. The brain has a complex redox context with steep local gradients in O 2 that can promote redox-cycling between melanin and diffusible redox-active chemical species. Here, we performed in vitro reverse engineering studies and report that melanins can redox-cycle with two common redox-active drugs. Experimentally, we used two melanin models: a convenient natural melanin derived from cuttlefish (Sepia melanin) and a synthetic cysteinyldopamine-dopamine core-shell model of neuromelanin. One drug, acetaminophen (APAP), has been used clinically for over a century, and recent studies suggest that low doses of APAP can protect the brain from oxidative-stress-induced toxicity and neurodegeneration, while higher doses can have toxic effects in the brain. The second drug, clozapine (CLZ), is a second generation antipsychotic with polypharmacological activities that remain incompletely understood. These in vitro observations suggest that the redox activities of drugs may be relevant to their modes-of-action, and that melanins may interact with drugs in ways that affect their activities, metabolism, and toxicities.

  10. Applying photoacoustics to quantification of melanin concentration in retinal pigment epithelium (Conference Presentation)

    Science.gov (United States)

    Shu, Xiao; Zhang, Hao F.; Liu, Wenzhong

    2016-03-01

    The melanin in the retinal pigment epithelium (RPE) protects retina and other ocular tissues by photo-screening and acting as antioxidant and free radical scavenger. It helps maintain normal visual functions since human eye is subjected to lifelong high oxygen stress and photon exposure. Loss of the RPE melanin weakens the protection mechanism and jeopardizes ocular health. Local decrease in the RPE melanin concentration is believed to be both a cause and a sign of early-stage age-related macular degeneration (AMD), the leading blinding disease in developed world. Current technology cannot quantitatively measure the RPE melanin concentration which might be a promising marker in early AMD screening. Photoacoustic ophthalmoscopy (PAOM), as an emerging optical absorption-based imaging technology, can potentially be applied to measure the RPE melanin concentration if the dependence of the detectable photoacoustic (PA) signal amplitudes on the RPE melanin concentrations is verified. In this study, we tested the feasibility of using PA signal ratio from RPE melanin and the nearby retinal blood vessels as an indicator of the RPE melanin variation. A novel whole eye optical model was designed and Monte Carlo modeling of light (MCML) was employed. We examined the influences on quantification from PAOM axial resolution, the depth and diameter of the retinal blood vessel, and the RPE thickness. The results show that the scheme is robust to individual histological and illumination variations. This study suggests that PAOM is capable of quantitatively measuring the RPE melanin concentration in vivo.

  11. Different culture media containing methyldopa for melanin production by Cryptococcus species

    Directory of Open Access Journals (Sweden)

    Ralciane de Paula Menezes

    2011-10-01

    Full Text Available INTRODUCTION: Melanin production by species of Cryptococcus is widely used to characterize C. neoformans complex in mycology laboratories. This study aims to test the efficacy of methyldopa from pharmaceutical tablet as a substrate for melanin production, to compare the production of melanin using different agar base added with methyldopa, and to compare the melanin produced in those media with that produced in Niger seed agar and sunflower seed agar by C. neoformans, C. laurentii, and C. albidus. Two isolates of each species, C. neoformans, C. laurentii, and C. albidus, and one of Candida albicans were used to experimentally detect conditions for melanin production. METHODS: The following media were tested: Mueller-Hinton agar (MHA, brain and heart infusion agar (BHIA, blood agar base (BAB, and minimal medium agar (MMA, all added with methyldopa, and the media Niger seed agar (NSA and sunflower seed agar (SSA. RESULTS: All isolates grew in most of the culture media after 24h. Strains planted on media BAB and BHIA showed growth only after 48h. All isolates produced melanin in MMA, MHA, SSA, and NSA media. CONCLUSIONS: Methyldopa in the form pharmaceutical tablet can be used as a substrate for melanin production by Cryptococcus species; minimal medium plus methyldopa was more efficient than the BAB, MHA, and BHIA in the melanin production; and NSA and SSA, followed by MMA added with methyldopa, were more efficient than other media studied for melanin production by all strains studied.

  12. Production and Cytotoxicity of Extracellular Insoluble and Droplets of Soluble Melanin by Streptomyces lusitanus DMZ-3

    Directory of Open Access Journals (Sweden)

    D. N. Madhusudhan

    2014-01-01

    Full Text Available A Streptomyces lusitanus DMZ-3 strain with potential to synthesize both insoluble and soluble melanins was detected. Melanins are quite distinguished based on their solubility for varied biotechnological applications. The present investigation reveals the enhanced production of insoluble and soluble melanins in tyrosine medium by a single culture. Streptomyces lusitanus DMZ-3 was characterized by 16S rRNA gene analysis. An enhanced production of 5.29 g/L insoluble melanin was achieved in a submerged bioprocess following response surface methodology. Combined interactive effect of temperature (50°C, pH (8.5, tyrosine (2.0 g/L, and beef extract (0.5 g/L were found to be critical variables for enhanced production in central composite design analysis. An optimized indigenous slant culture system was an innovative approach for the successful production (264 mg/L of pure soluble melanin from the droplets formed on the surface of the culture. Both insoluble and soluble melanins were confirmed and characterized by Chemical, reactions, UV, FTIR, and TLC analysis. First time, cytotoxic study of melanin using brine shrimps was reported. Maximum cytotoxic activity of soluble melanin was Lc50-0.40 µg/mL and insoluble melanin was Lc50-0.80 µg/mL.

  13. B16F1 melanoma cells upregulate melanin synthesis after photodynamic therapy

    International Nuclear Information System (INIS)

    Moder, A.; Gassner, F.; Krammer, B.; Thalhamer, J.; Hammerl, P.

    2003-01-01

    Full text: The success of photodynamic therapy (PDT) of melanotic tumors is severely limited by insufficient penetration of light into deeper tissue layers. In this study, we analyzed the effect of PDT on the melanin production of the melanoma cell line B16F1. In vitro, these cells produce only little melanin. However, after PDT we found a dramatic elevation in intracellular melanin. Melanin production increased with, both, the concentration of the sensitizing agent and the light dose, and was found to continue for several hours after cell death. PDT-induced melanin synthesis was not prevented by the addition of cycloheximide or actinomycin D prior to irradiation, indicating that de-novo protein synthesis and transcriptional activity are not required for this effect. We also analyzed tyrosinase activity, a key enzyme in melanin biosynthesis, in PDT-treated B16 cells. Tyrosinase activity was found in PDT-treated as well as untreated cells. Cell fractionation experiments showed that tyrosinase was present in the cytosolic as well as the melanosomal fractions of, both, PDT-treated (melanin-high) as well as untreated (melanin-low) cells. These data indicate that PDT-induced production of melanin is not controlled at the transcriptional or translational level and that tyrosinase is not likely an essential regulator in this process. (author)

  14. Melanin, a promising radioprotector: Mechanisms of actions in a mice model

    Energy Technology Data Exchange (ETDEWEB)

    Kunwar, A., E-mail: amitbio@rediffmail.com [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Adhikary, B. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Jayakumar, S. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Barik, A. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Chattopadhyay, S. [Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Raghukumar, S. [Myko Tech Private Limited, Dona Paula, Goa‐403004 (India); Priyadarsini, K.I., E-mail: kindira@barc.gov.in [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-10-15

    The radioprotective effect of extracellular melanin, a naturally occurring pigment, isolated from the fungus Gliocephalotrichum simplex was examined in BALB/C mice, and the probable mechanism of action was established. At an effective dose of 50 mg/kg body weight, melanin exhibited both prophylactic and mitigative activities, increasing the 30-day survival of mice by 100% and 60%, respectively, after exposure to radiation (7 Gy, whole body irradiation (WBI)). The protective activity of melanin was primarily due to inhibition of radiation-induced hematopoietic damages as evidenced by improvement in spleen parameters such as index, total cellularity, endogenous colony forming units, and maintenance of circulatory white blood cells and platelet counts. Melanin also reversed the radiation-induced decrease in ERK phosphorylation in splenic tissue, which may be the key feature in its radioprotective action. Additionally, our results indicated that the sustained activation of AKT, JNK and P38 proteins in splenic tissue of melanin pre-treated group may also play a secondary role. This was also supported by the fact that melanin could prevent apoptosis in splenic tissue by decreasing BAX/Bcl-XL ratio, and increasing the expressions of the proliferation markers (PCNA and Cyclin D1), compared to the radiation control group. Melanin also reduced the oxidative stress in hepatic tissue and abrogated immune imbalance by reducing the production of pro-inflammatory cytokines (IL6 and TNFα). In conclusion, our results confirmed that fungal melanin is a very effective radioprotector against WBI and the probable mechanisms of radioprotection are due to modulation in pro-survival (ERK) signaling, prevention of oxidative stress and immunomodulation. -- Highlights: ► Melanin showed promising radioprotection under pre and post irradiation condition. ► Melanin protects the hematopoietic system from radiation induced damage. ► Melanin modulates pro-survival pathways, immune system

  15. Melanin fate in the human epidermis: a reassessment of how best to detect and analyse histologically.

    Science.gov (United States)

    Joly-Tonetti, Nicolas; Wibawa, Judata I D; Bell, Mike; Tobin, Desmond

    2016-07-01

    Melanin is the predominant pigment responsible for skin colour and is synthesized by the melanocyte in the basal layer of the epidermis and then transferred to surrounding keratinocytes. Despite its optical properties, melanin is barely detectable in unstained sections of human epidermis. However, identification and localization of melanin is of importance for the study of skin pigmentation in health and disease. Current methods for the histologic quantification of melanin are suboptimal and are associated with significant risk of misinterpretation. The aim of this study was to reassess the existing literature and to develop a more effective histological method of melanin quantification in human skin. Moreover, we confirm that Warthin-Starry (WS) stain provides a much more sensitive and more specific melanin detection method than the commonplace Fontana-Masson (FM) stain. For example, WS staining sensitivity allowed the visualization of melanin even in very pale Caucasian skin that was missed by FM or Von Kossa (VK) stains. From our reassessment of the histology-related literature, we conclude that so-called melanin dust is most likely an artifact of discoloration due to non-specific silver deposition in the stratum corneum. Unlike FM and VK, WS was not associated with this non-specific stratum corneum darkening, misinterpreted previously as 'degraded' melanin. Finally, WS melanin particle counts were largely similar to previously reported manual counts by transmission electron microscopy, in contrast to both FM and VK. Together these findings allow us to propose a new histology/Image J-informed method for the accurate and precise quantification of epidermal melanin in skin. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol

    Directory of Open Access Journals (Sweden)

    Ryuji Uchida

    2014-04-01

    Full Text Available 2-Hydroxytyrosol (2-HT, originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH-stimulated melanin formation in intact B16 melanoma cells.

  17. Odontogenic Cyst with Verrucous Proliferation Exhibiting Melanin Pigmentation

    Science.gov (United States)

    Soni, Krupa Mehta; Ahmed, Junaid; Bhat, Keshava; Kottieth Pallam, Nandita; Lewis, Amitha Juanita

    2017-01-01

    Verrucous proliferation arising from odontogenic cysts is a rare entity. We report an unusual case of an infected odontogenic cyst with verrucous proliferation and melanin pigmentation in a 13-year-old male patient who presented with an intraoral swelling in relation to impacted teeth 26 and 27. The enucleated lesion was diagnosed as an odontogenic keratocyst and the patient died within two years of presentation due to multiple recurrences. The clinical, radiological, and microscopic features of the lesion are presented with an attempt to discuss the etiopathogenesis. The case hereby reported is uncommon with only eight cases reported in the literature. PMID:28409045

  18. ESTIMATION OF MELANIN CONTENT IN IRIS OF HUMAN EYE

    Directory of Open Access Journals (Sweden)

    E. A. Genina

    2008-12-01

    Full Text Available Based on the experimental data obtained in vivo from digital analysis of color images of human irises, the mean melanin content in human eye irises has been estimated. For registration of color images the digital camera Olympus C-5060 has been used. The images have been obtained from irises of healthy volunteers as well as from irises of patients with open-angle glaucoma. The computer program has been developed for digital analysis of the images. The result has been useful for development of novel methods and optimization of already existing ones for non-invasive glaucoma diagnostics.

  19. Effects of melanin on the accumulation of exopolysaccharides by Aureobasidium pullulans grown on nitrate.

    Science.gov (United States)

    Zheng, Weifa; Campbell, Bradley S; McDougall, Barbara M; Seviour, Robert J

    2008-11-01

    Aureobasidium pullulans produced pullulan and melanin when grown in medium containing low nitrate levels. With high nitrate concentrations, however, this fungus produced a mixture of exopolysaccharides (EPS) without melanin synthesis. At 0.78 g l(-1) N as nitrate, where no melanin synthesis occurred, maximum EPS yields reached 6.92 g l(-1) and then decreased to the final yield of 2.36 g l(-1). Following melanin addition (0.1 g l(-1)), yields reached 7.02 g l(-1) at 48 h and fell to a final yield of 5.21 g l(-1). The EPS produced in high nitrate medium contained both pullulan and (1-->3)-beta-glucan, but only pullulan was produced with melanin-supplementation. With melanin addition a doubling of (1-->3)-beta-glucanase activity was observed in high nitrate medium compared to that without supplementation. On the other hand amylolytic activities disappeared in medium with melanin production or addition. Culture filtrates sustained a higher reducing capacity (RC) when melanin was present. Low RC appeared to reduce (1-->3)-beta-glucanase activity and increase amylolytic activities. Thus, higher RC appears to inhibit production/activity of amylose-degrading enzymes capable of degrading pullulan, and stimulates (1-->3)-beta-glucanase synthesis/activity, leading to a preferential accumulation of pullulan.

  20. Melanin binding study of clinical drugs with cassette dosing and rapid equilibrium dialysis inserts.

    Science.gov (United States)

    Pelkonen, Laura; Tengvall-Unadike, Unni; Ruponen, Marika; Kidron, Heidi; Del Amo, Eva M; Reinisalo, Mika; Urtti, Arto

    2017-11-15

    Melanin pigment is a negatively charged polymer found in pigmented human tissues. In the eye, iris, ciliary body, choroid and retinal pigment epithelium (RPE) are heavily pigmented. Several drug molecules are known to bind to melanin, but larger sets of drugs have not been compared often in similar test conditions. In this study, we introduce a powerful tool for screening of melanin binding. The binding of a set of 34 compounds to isolated porcine RPE melanin was determined by cassette (n-in-one) dosing in rapid equilibrium dialysis inserts and the binding was quantitated with LC-MS/MS analytics. The compounds represented large variety in melanin binding (from 8.6%, ganciclovir) to over 95% bound (ampicillin and ciprofloxacin). The data provides information on melanin binding of small molecular weight compounds that are used for ocular (e.g. brinzolamide, ganciclovir) and systemic (e.g. tizanidine, indomethacin) therapy. Interestingly, competition among compounds was seen for melanin binding and the binding did not show any correlation with plasma protein binding. These results increase the understanding of melanin binding of ocular drugs and can be further exploited to predict pharmacokinetics in the eye. Pigment binding provides an interesting option for improved drug distribution to retina and choroid that are difficult target tissues in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Condition-dependent expression of melanin-based coloration in the Eurasian kestrel

    NARCIS (Netherlands)

    Piault, Romain; van den Brink, Valentijn; Roulin, Alexandre

    Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent.

  2. CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

    Directory of Open Access Journals (Sweden)

    TABORDA Valeria B.A.

    1999-01-01

    Full Text Available Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.

  3. Macular pigment and melanin in age-related maculopathy in a general population

    NARCIS (Netherlands)

    Berendschot, Tos T. J. M.; Willemse-Assink, Jacqueline J. M.; Bastiaanse, Mieke; de Jong, Paulus T. V. M.; van Norren, Dirk

    2002-01-01

    It has been suggested that macular pigment (MP) and melanin may protect against age-related maculopathy (ARM). To check this, MP and melanin optical density were measured in a random population-based sample of subjects 55 years of age or older. Spectral fundus reflectance of the fovea was measured

  4. (Pheo)melanin photosensitizes UVA-induced DNA damage in cultured human melanocytes

    NARCIS (Netherlands)

    Wenczl, E.; Schans, G.P. van der; Roza, L.; Kolb, R.M.; Timmerman, A.J.; Smit, N.P.M.; Pavel, S.; Schothorst, A.A.

    1998-01-01

    The question of whether melanins are photoprotecting and/or photosensitizing in human skin cells continues to be debated. To evaluate the role of melanin upon UVA irradiation, DNA single-strand breaks (ssb) were measured in human melanocytes differing only in the amount of pigment produced by

  5. Transferring Biomarker into Molecular Probe: Melanin Nanoparticle as a Naturally Active Platform for Multimodality Imaging

    OpenAIRE

    Fan, Quli; Cheng, Kai; Hu, Xiang; Ma, Xiaowei; Zhang, Ruiping; Yang, Min; Lu, Xiaomei; Xing, Lei; Huang, Wei; Gambhir, Sanjiv Sam; Cheng, Zhen

    2014-01-01

    Developing multifunctional and easily prepared nanoplatforms with integrated different modalities is highly challenging for molecular imaging. Here, we report the successful transfer of an important molecular target, melanin, into a novel multimodality imaging nanoplatform. Melanin is abundantly expressed in melanotic melanomas and thus has been actively studied as a target for melanoma imaging. In our work, the multifunctional biopolymer nanoplatform based on ultrasmall (

  6. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine.

    Directory of Open Access Journals (Sweden)

    Rodrigo Almeida-Paes

    Full Text Available Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC and minimal fungicidal concentrations (MFC of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.

  7. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine.

    Science.gov (United States)

    Almeida-Paes, Rodrigo; Figueiredo-Carvalho, Maria Helena Galdino; Brito-Santos, Fábio; Almeida-Silva, Fernando; Oliveira, Manoel Marques Evangelista; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.

  8. Gingival melanin depigmentation by Er:YAG laser: A literature review.

    Science.gov (United States)

    Pavlic, Verica; Brkic, Zlata; Marin, Sasa; Cicmil, Smiljka; Gojkov-Vukelic, Mirjana; Aoki, Akira

    2017-10-06

    Laser ablation is recently suggested as a most effective and reliable technique for depigmentation of melanin hyperpigmented gingiva. To date, different lasers have been used for gingival depigmentation (CO 2 , diode, Nd:YAG, Er:YAG and Er,Cr:YSGG lasers). The use of Er:YAG laser for depigmentation of melanin hyperpigmented gingiva has gained increasing importance in recent years. The purpose of this study was to report removal of gingival melanin pigmentation using an Er:YAG laser in a literature review. The main outcomes, such as improvement of signs (clinical parameters of bleeding, erythema, swelling and wound healing), symptoms (pain) and melanin recurrence/repigmentation were measured. The literature demonstrated that depigmentation of gingival melanin pigmentation can be performed safely and effectively by Er:YAG laser resulting in healing and an esthetically significant improvement of gingival discoloration. Thus, Er:YAG laser seems to be safe and useful in melanin depigmentation procedure. However, the main issue in giving the final conclusion of the optimal Er:YAG laser use in melanin depigmentation is that, to date, studies are offering completely discrepant Er:YAG laser procedure protocols (complex settings of laser parameters), and different criteria for the assessment of depigmentation and repigmentation (recurrence), thus hampering the comparison of the results. Therefore, further studies are necessary to give an optimal recommendation on the use of Er:YAG laser in gingival melanin hyperpigmentation.

  9. Reflectance Spectra of Peacock Feathers and the Turning Angles of Melanin Rods in Barbules.

    Science.gov (United States)

    Okazaki, Toshio

    2018-02-01

    I analyzed the association between the reflectance spectra and melanin rod arrangement in barbules of the eyespot of peacock feathers. The reflectance spectra from the yellow-green feather of the eyespot indicated double peaks of 430 and 540 nm. The maximum reflectance spectrum of the blue feather was 480 nm, and that of the dark blue feather was 420 nm. The reflectance spectra from brown feathers indicated double peaks of 490 and 610 nm. Transmission electron microscopic analysis confirmed that melanin rods were arranged fanwise in the outer layer toward the barbule tips. In addition, using polarized light microscope, I attempted to determine whether the turning angles of melanin rods in the barbules reflected different colors. The turning angle of the polarizing axis of the barbules was supported by that of the melanin rods, observed using transmission electron microscopic images. To compare the turning angle of melanin rods in the respective barbules, I calculated the opening width of the fanwise melanin rods by dividing the width of the barbules by the turning angle of the polarizing axis of barbules and obtained a positive correlation between the reflectance spectra and opening width of the fanwise melanin rods. Moreover, the widely spreading reflection from the barbules may occur because of the fanwise melanin rod arrangement.

  10. Interactions between Melanin Enzymes and Their Atypical Recruitment to the Secretory Pathway by Palmitoylation

    Directory of Open Access Journals (Sweden)

    Srijana Upadhyay

    2016-11-01

    Full Text Available Melanins are biopolymers that confer coloration and protection to the host organism against biotic or abiotic insults. The level of protection offered by melanin depends on its biosynthesis and its subcellular localization. Previously, we discovered that Aspergillus fumigatus compartmentalizes melanization in endosomes by recruiting all melanin enzymes to the secretory pathway. Surprisingly, although two laccases involved in the late steps of melanization are conventional secretory proteins, the four enzymes involved in the early steps of melanization lack a signal peptide or a transmembrane domain and are thus considered “atypical” secretory proteins. In this work, we found interactions among melanin enzymes and all melanin enzymes formed protein complexes. Surprisingly, the formation of protein complexes by melanin enzymes was not critical for their trafficking to the endosomal system. By palmitoylation profiling and biochemical analyses, we discovered that all four early melanin enzymes were strongly palmitoylated during conidiation. However, only the polyketide synthase (PKS Alb1 was strongly palmitoylated during both vegetative hyphal growth and conidiation when constitutively expressed alone. This posttranslational lipid modification correlates the endosomal localization of all early melanin enzymes. Intriguingly, bioinformatic analyses predict that palmitoylation is a common mechanism for potential membrane association of polyketide synthases (PKSs and nonribosomal peptide synthetases (NRPSs in A. fumigatus. Our findings indicate that protein-protein interactions facilitate melanization by metabolic channeling, while posttranslational lipid modifications help recruit the atypical enzymes to the secretory pathway, which is critical for compartmentalization of secondary metabolism.

  11. EFFECT OF CADMIUM(II) ON FREE RADICALS IN DOPA-MELANIN TESTED BY EPR SPECTROSCOPY.

    Science.gov (United States)

    Zdybel, Magdalena; Pilawa, Barbara; Chodurek, Ewa

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy may be applied to examine interactions of melanin with metal ions and drugs. In this work EPR method was used to examination of changes in free radical system of DOPA-melanin--the model eumelanin after complexing with diamagnetic cadmium(II) ions. Cadmium(II) may affect free radicals in melanin and drugs binding by this polymer, so the knowledge of modification of properties and free radical concentration in melanin is important to pharmacy. The effect of cadmium(II) in different concentrations on free radicals in DOPA-melanin was determined. EPR spectra of DOPA-melanin, and DOPA-melanin complexes with cadmium(II) were measured by an X-band (9.3 GHz) EPR spectrometer produced by Radiopan (Poznań, Poland) and the Rapid Scan Unit from Jagmar (Krak6w, Poland). The DOPA (3,4-dihydroxyphenylalanine) to metal ions molar ratios in the reaction mixtures were 2:1, 1:1, and 1: 2. High concentrations of o-semiquinone (g ~2.0040) free radicals (~10(21)-10(22) spin/g) characterize DOPA-melanin and its complexes with cadmium(II). Formation of melanin complexes with cadmium(II) increase free radical concentration in DOPA-melanin. The highest free radical concentration was obtained for DOPA-melanin-cadmium(II) (1:1) complexes. Broad EPR lines with linewidths: 0.37-0.73 mT, were measured. Linewidths increase after binding of cadmium(II) to melanin. Changes of integral intensities and linewidths with increasing microwave power indicate the homogeneous broadening of EPR lines, independently on the metal ion concentration. Slow spin-lattice relaxation processes existed in all the tested samples, their EPR lines saturated at low microwave powers. Cadmium(II) causes fastening of spin-lattice relaxation processes in DOPA-melanin. The EPR results bring to light the effect of cadmium(II) on free radicals in melanin, and probably as the consequence on drug binding to eumelanin.

  12. The nanomechanical role of melanin granules in the retinal pigment epithelium.

    Science.gov (United States)

    Sarna, Michal; Olchawa, Magdalena; Zadlo, Andrzej; Wnuk, Dawid; Sarna, Tadeusz

    2017-04-01

    Nanomechanical properties of cells and tissues, in particular their elasticity, play an important role in different physiological and pathological processes. Recently, we have demonstrated that melanin granules dramatically modify nanomechanical properties of melanoma cells making them very stiff and, as a result, less aggressive. Although the mechanical effect of melanin granules was demonstrated in pathological cells, it was never studied in the case of normal cells. In this work, we analyzed the impact of melanin granules on nanomechanical properties of primary retinal pigment epithelium tissue fragments isolated from porcine eyes. The obtained results clearly show that melanin granules are responsible for the exceptional nanomechanical properties of the tissue. Our findings suggest that melanin granules in the retinal pigment epithelium may play an important role in sustaining the stiffness of this single cell layer, which functions as a natural mechanical barrier separating the retina from the choroid. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Synthetic melanin bound to subunit vaccine antigens significantly enhances CD8+ T-cell responses.

    Directory of Open Access Journals (Sweden)

    Antoine F Carpentier

    Full Text Available Cytotoxic T-lymphocytes (CTLs play a key role in immunity against cancer; however, the induction of CTL responses with currently available vaccines remains difficult. Because several reports have suggested that pigmentation and immunity might be functionally linked, we investigated whether melanin can act as an adjuvant in vaccines. Short synthetic peptides (8-35 amino acids long containing T-cell epitopes were mixed with a solution of L-Dopa, a precursor of melanin. The mixture was then oxidized to generate nanoparticles of melanin-bound peptides. Immunization with melanin-bound peptides efficiently triggered CTL responses in mice, even against self-antigens and at a very low dose of peptides (microgram range. Immunization against a tumor antigen inhibited the growth of established tumors in mice, an effect that was abrogated by the depletion of CD8+ lymphocytes. These results demonstrate the efficacy of melanin as a vaccine adjuvant.

  14. Accumulation of melanin in the peritoneum causes black abdomens in broilers.

    Science.gov (United States)

    Wang, J; Wang, Y; Luo, C; Qu, H; Shu, D

    2014-03-01

    A suspected case of localized visceral hyperpigmentation was described for a breed of broiler in China. Using optical microscopy, the accumulation of pigments in the abdominal skin and visceral peritoneum was observed. Electron microscopy was used to further study the ultrastructure of the pigmented peritoneum, and pigment granules resembling melanosomes at different stages were found, and melanocytes were present in this tissue. Infrared spectroscopy was used to analyze the physical-chemical properties of pigments extracted from these broilers. Using synthetic melanin as a reference and the melanin from the peritoneum of Silkie fowls as a control, the pigments in the peritonea of these broilers were found to be melanin, and it had a chemical structure similar to that of melanin from the Silkie fowl peritoneum. In this way, the black abdomens of these broilers were found to have been caused by accumulation of melanin produced by melanocytes in visceral peritonea.

  15. Radiation, heat and anti-melanin drug response of a transformed mouse embryo cell line with varying melanin content

    Energy Technology Data Exchange (ETDEWEB)

    Raaphorst, G.P.; Azzam, E.I.

    1987-11-01

    The R25 melanoma-like cell line, produced by transformation of the C3H-10T1/2 mouse embryo cell line, was studied to determine 1) whether the increased size of the survival curve shoulder indicated an increased capacity for radiation damage repair, 2) whether the presence of melanin influences radiosensitivity and heat sensitivity and 3) whether this melanoma cell line is sensitive in its response to anti-melanoma chemical agents compared to its normal parental cell line and other transformants not exhibiting melanoma like properties. (U.K.).

  16. Comparison of Antioxidant Activities of Melanin Fractions from Chestnut Shell

    Directory of Open Access Journals (Sweden)

    Zeng-Yu Yao

    2016-04-01

    Full Text Available Chestnut shell melanin can be used as a colorant and antioxidant, and fractionated into three fractions (Fr. 1, Fr. 2, and Fr. 3 with different physicochemical properties. Antioxidant activities of the fractions were comparatively evaluated for the first time. The fractions exhibited different antioxidative potential in different evaluation systems. Fr. 1, which is only soluble in alkaline water, had the strongest peroxidation inhibition and superoxide anion scavenging activity; Fr. 2, which is soluble in alkaline water and hydrophilic organic solvents but insoluble in neutral and acidic water, had the greatest power to chelate ferrous ions; and Fr. 3, which is soluble both in hydrophilic organic solvents and in water at any pH conditions, had the greatest hydroxyl (·OH and 1,1-diphenyl-2-picryl-hydrazyl (DPPH· radicals scavenging abilities, reducing power, and phenolic content. The pigment fractions were superior to butylated hydroxytolune (BHT in ·OH and DPPH· scavenging and to ethylene diamine tetraacetic acid (EDTA in the Fe2+–chelation. They were inferior to BHT in peroxidation inhibition and O2·− scavenging and reducing power. However, BHT is a synthetic antioxidant and cannot play the colorant role. The melanin fractions might be used as effective biological antioxidant colorants.

  17. Role of Melanin in Melanocyte Dysregulation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Noah C. Jenkins

    2013-01-01

    Full Text Available We have recently reported a potential alternative tumor suppressor function for p16 relating to its capacity to regulate oxidative stress and observed that oxidative dysregulation in p16-depleted cells was most profound in melanocytes, compared to keratinocytes or fibroblasts. Moreover, in the absence of p16 depletion or exogenous oxidative insult, melanocytes exhibited significantly higher basal levels of reactive oxygen species (ROS than these other epidermal cell types. Given the role of oxidative stress in melanoma development, we speculated that this increased susceptibility of melanocytes to oxidative stress (and greater reliance on p16 for suppression of ROS may explain why genetic compromise of p16 is more commonly associated with predisposition to melanoma rather than other cancers. Here we show that the presence of melanin accounts for this differential oxidative stress in normal and p16-depleted melanocytes. Thus the presence of melanin in the skin appears to be a double-edged sword: it protects melanocytes as well as neighboring keratinocytes in the skin through its capacity to absorb UV radiation, but its synthesis in melanocytes results in higher levels of intracellular ROS that may increase melanoma susceptibility.

  18. Madecassoside inhibits melanin synthesis by blocking ultraviolet-induced inflammation.

    Science.gov (United States)

    Jung, Eunsun; Lee, Jung-A; Shin, Seoungwoo; Roh, Kyung-Baeg; Kim, Jang-Hyun; Park, Deokhoon

    2013-12-16

    Madecassoside (MA), a pentacyclic triterpene isolated from Centella asitica (L.), is used as a therapeutic agent in wound healing and also as an anti-inflammatory and anti-aging agent. However, the involvement of MA in skin-pigmentation has not been reported. This study was conducted to investigate the effects of MA on ultraviolet (UV)-induced melanogenesis and mechanisms in a co-culture system of keratinocytes and melanocytes. MA significantly inhibited UVR-induced melanin synthesis and melanosome transfer in the co-culture system. These effects were further demonstrated by the MA-induced inhibition of protease-activated receptor-2 expression and its signaling pathway, cyclooxygenase-2, prostaglandin E2 and prostaglandin F2 alpha in keratinocytes. The clinical efficacy of MA was confirmed on artificially tanned human skin. MA significantly reduced UV-induced melanin index at 8 weeks after topical application. Overall, the study demonstrated significant benefits of MA use in the inhibition of hyperpigmentation caused by UV irradiation.

  19. Madecassoside Inhibits Melanin Synthesis by Blocking Ultraviolet-Induced Inflammation

    Directory of Open Access Journals (Sweden)

    Eunsun Jung

    2013-12-01

    Full Text Available Madecassoside (MA, a pentacyclic triterpene isolated from Centella asitica (L., is used as a therapeutic agent in wound healing and also as an anti-inflammatory and anti-aging agent. However, the involvement of MA in skin-pigmentation has not been reported. This study was conducted to investigate the effects of MA on ultraviolet (UV-induced melanogenesis and mechanisms in a co-culture system of keratinocytes and melanocytes. MA significantly inhibited UVR-induced melanin synthesis and melanosome transfer in the co-culture system. These effects were further demonstrated by the MA-induced inhibition of protease-activated receptor-2 expression and its signaling pathway, cyclooxygenase-2, prostaglandin E2 and prostaglandin F2 alpha in keratinocytes. The clinical efficacy of MA was confirmed on artificially tanned human skin. MA significantly reduced UV-induced melanin index at 8 weeks after topical application. Overall, the study demonstrated significant benefits of MA use in the inhibition of hyperpigmentation caused by UV irradiation.

  20. Multimodal microscopy and the stepwise multi-photon activation fluorescence of melanin

    Science.gov (United States)

    Lai, Zhenhua

    The author's work is divided into three aspects: multimodal microscopy, stepwise multi-photon activation fluorescence (SMPAF) of melanin, and customized-profile lenses (CPL) for on-axis laser scanners, which will be introduced respectively. A multimodal microscope provides the ability to image samples with multiple modalities on the same stage, which incorporates the benefits of all modalities. The multimodal microscopes developed in this dissertation are the Keck 3D fusion multimodal microscope 2.0 (3DFM 2.0), upgraded from the old 3DFM with improved performance and flexibility, and the multimodal microscope for targeting small particles (the "Target" system). The control systems developed for both microscopes are low-cost and easy-to-build, with all components off-the-shelf. The control system have not only significantly decreased the complexity and size of the microscope, but also increased the pixel resolution and flexibility. The SMPAF of melanin, activated by a continuous-wave (CW) mode near-infrared (NIR) laser, has potential applications for a low-cost and reliable method of detecting melanin. The photophysics of melanin SMPAF has been studied by theoretical analysis of the excitation process and investigation of the spectra, activation threshold, and photon number absorption of melanin SMPAF. SMPAF images of melanin in mouse hair and skin, mouse melanoma, and human black and white hairs are compared with images taken by conventional multi-photon fluorescence microscopy (MPFM) and confocal reflectance microscopy (CRM). SMPAF images significantly increase specificity and demonstrate the potential to increase sensitivity for melanin detection compared to MPFM images and CRM images. Employing melanin SMPAF imaging to detect melanin inside human skin in vivo has been demonstrated, which proves the effectiveness of melanin detection using SMPAF for medical purposes. Selective melanin ablation with micrometer resolution has been presented using the Target system

  1. Photoreactivity of biologically active compounds. VII. Interaction of antimalarial drugs with melanin in vitro as part of phototoxicity screening.

    Science.gov (United States)

    Kristensen, S; Orsteen, A L; Sande, S A; Tønnesen, H H

    1994-10-01

    The drugs commonly used in the treatment of malaria are photochemically unstable. Several of these compounds accumulate in melanin-rich tissues and cause toxic reactions which may be light induced. As part of the screening of the photochemical properties and phototoxic capabilities of antimalarials, the in vitro interaction of eight antimalarials with melanin was studied. The dissociation constant for the drug-melanin complex and the relative number of binding sites on melanin were estimated for six of the drugs using a curve-fitting program. The reaction rate for the formation of the melanin-drug complex was determined, and the complexes were further characterized by zeta potential measurements.

  2. Data on melanin production in B16F1 melanoma cells in the presence of emu oil

    Directory of Open Access Journals (Sweden)

    Minoru Ito

    2016-12-01

    Full Text Available Here, we present data on the effects of emu oil, obtained from emu (Dromaius novaehollandiae fat deposits, on melanogenesis in B16F1 murine melanoma cells. The cells were cultured in media containing different concentrations of emu oil, and the melanin content of these cells was measured using a microplate reader. Next, melanin content was measured for cells cultured with α-melanocyte-stimulating hormone. This article reports the different melanin contents as μg melanin/mg cellular protein, by using bar graphs with error bars. The present data imply that emu oil reduces the cellular melanin production.

  3. A Non-canonical Melanin Biosynthesis Pathway Protects Aspergillus terreus Conidia from Environmental Stress.

    Science.gov (United States)

    Geib, Elena; Gressler, Markus; Viediernikova, Iuliia; Hillmann, Falk; Jacobsen, Ilse D; Nietzsche, Sandor; Hertweck, Christian; Brock, Matthias

    2016-05-19

    Melanins are ubiquitous pigments found in all kingdoms of life. Most organisms use them for protection from environmental stress, although some fungi employ melanins as virulence determinants. The human pathogenic fungus Aspergillus fumigatus and related Ascomycetes produce dihydroxynaphthalene- (DHN) melanin in their spores, the conidia, and use it to inhibit phagolysosome acidification. However, biosynthetic origin of melanin in a related fungus, Aspergillus terreus, has remained a mystery because A. terreus lacks genes for synthesis of DHN-melanin. Here we identify genes coding for an unusual NRPS-like enzyme (MelA) and a tyrosinase (TyrP) that A. terreus expressed under conidiation conditions. We demonstrate that MelA produces aspulvinone E, which is activated for polymerization by TyrP. Functional studies reveal that this new pigment, Asp-melanin, confers resistance against UV light and hampers phagocytosis by soil amoeba. Unexpectedly, Asp-melanin does not inhibit acidification of phagolysosomes, thus likely contributing specifically to survival of A. terreus conidia in acidic environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils.

    Science.gov (United States)

    Colleary, Caitlin; Dolocan, Andrei; Gardner, James; Singh, Suresh; Wuttke, Michael; Rabenstein, Renate; Habersetzer, Jörg; Schaal, Stephan; Feseha, Mulugeta; Clemens, Matthew; Jacobs, Bonnie F; Currano, Ellen D; Jacobs, Louis L; Sylvestersen, Rene Lyng; Gabbott, Sarah E; Vinther, Jakob

    2015-10-13

    In living organisms, color patterns, behavior, and ecology are closely linked. Thus, detection of fossil pigments may permit inferences about important aspects of ancient animal ecology and evolution. Melanin-bearing melanosomes were suggested to preserve as organic residues in exceptionally preserved fossils, retaining distinct morphology that is associated with aspects of original color patterns. Nevertheless, these oblong and spherical structures have also been identified as fossilized bacteria. To date, chemical studies have not directly considered the effects of diagenesis on melanin preservation, and how this may influence its identification. Here we use time-of-flight secondary ion mass spectrometry to identify and chemically characterize melanin in a diverse sample of previously unstudied extant and fossil taxa, including fossils with notably different diagenetic histories and geologic ages. We document signatures consistent with melanin preservation in fossils ranging from feathers, to mammals, to amphibians. Using principal component analyses, we characterize putative mixtures of eumelanin and phaeomelanin in both fossil and extant samples. Surprisingly, both extant and fossil amphibians generally exhibit melanosomes with a mixed eumelanin/phaeomelanin composition rather than pure eumelanin, as assumed previously. We argue that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils. This refutes the hypothesis that such fossil microbodies could be bacteria, and demonstrates that melanin is widely responsible for the organic soft tissue outlines in vertebrates found at exceptional fossil localities, thus allowing for the reconstruction of certain aspects of original pigment patterns.

  5. Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils

    Science.gov (United States)

    Colleary, Caitlin; Dolocan, Andrei; Gardner, James; Singh, Suresh; Wuttke, Michael; Rabenstein, Renate; Habersetzer, Jörg; Schaal, Stephan; Feseha, Mulugeta; Clemens, Matthew; Jacobs, Bonnie F.; Currano, Ellen D.; Jacobs, Louis L.; Sylvestersen, Rene Lyng; Gabbott, Sarah E.; Vinther, Jakob

    2015-01-01

    In living organisms, color patterns, behavior, and ecology are closely linked. Thus, detection of fossil pigments may permit inferences about important aspects of ancient animal ecology and evolution. Melanin-bearing melanosomes were suggested to preserve as organic residues in exceptionally preserved fossils, retaining distinct morphology that is associated with aspects of original color patterns. Nevertheless, these oblong and spherical structures have also been identified as fossilized bacteria. To date, chemical studies have not directly considered the effects of diagenesis on melanin preservation, and how this may influence its identification. Here we use time-of-flight secondary ion mass spectrometry to identify and chemically characterize melanin in a diverse sample of previously unstudied extant and fossil taxa, including fossils with notably different diagenetic histories and geologic ages. We document signatures consistent with melanin preservation in fossils ranging from feathers, to mammals, to amphibians. Using principal component analyses, we characterize putative mixtures of eumelanin and phaeomelanin in both fossil and extant samples. Surprisingly, both extant and fossil amphibians generally exhibit melanosomes with a mixed eumelanin/phaeomelanin composition rather than pure eumelanin, as assumed previously. We argue that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils. This refutes the hypothesis that such fossil microbodies could be bacteria, and demonstrates that melanin is widely responsible for the organic soft tissue outlines in vertebrates found at exceptional fossil localities, thus allowing for the reconstruction of certain aspects of original pigment patterns. PMID:26417094

  6. Stepwise multiphoton activation fluorescence reveals a new method of melanin detection

    Science.gov (United States)

    Lai, Zhenhua; Kerimo, Josef; Mega, Yair; DiMarzio, Charles A.

    2013-06-01

    The stepwise multiphoton activated fluorescence (SMPAF) of melanin, activated by a continuous-wave mode near infrared (NIR) laser, reveals a broad spectrum extending from the visible spectra to the NIR and has potential application for a low-cost, reliable method of detecting melanin. SMPAF images of melanin in mouse hair and skin are compared with conventional multiphoton fluorescence microscopy and confocal reflectance microscopy (CRM). By combining CRM with SMPAF, we can locate melanin reliably. However, we have the added benefit of eliminating background interference from other components inside mouse hair and skin. The melanin SMPAF signal from the mouse hair is a mixture of a two-photon process and a third-order process. The melanin SMPAF emission spectrum is activated by a 1505.9-nm laser light, and the resulting spectrum has a peak at 960 nm. The discovery of the emission peak may lead to a more energy-efficient method of background-free melanin detection with less photo-bleaching.

  7. Structural Studies of Bleached Melanin by Synchrotron Small-angle X-ray Scattering¶

    Energy Technology Data Exchange (ETDEWEB)

    Littrell, Kenneth C.; Gallas, James M.; Zajac, Gerry W.; Thiyagarajan, Pappannan

    2003-01-01

    Small-angle X-ray scattering was used to measure the effects of chemical bleaching on the size and morphology of tyrosine-derived synthetic melanin dispersed in aqueous media. The average size as measured by the radius of gyration of the melanin particles in solution, at neutral to mildly basic pH, decreases from 16.5 to 12.5 angstroms with increased bleaching. The melanin particles exhibit scattering characteristic of sheet-like structures with a thickness of approximately 11 angstroms at all but the highest levels of bleaching. The scattering data are well described by the form factor for scattering from a pancake-like circular cylinder. These data are consistent with the hypothesis that unbleached melanin, at neutral to mildly basic pH, is a planar aggregate of 6- to 10-nm-sized melanin protomolecules, hydrogen bonded through their quinone and phenolic perimeters. The observed decrease in melanin particle size with increased bleaching is interpreted as evidence for deaggregation, most probably the result of oxidative disruption of hydrogen bonds and an increase in the number of charged, carboxylic acid groups, whereby the melanin aggregates disassociate into units composed of decreasing numbers of protomolecules.

  8. Melanin quantification by in vitro and in vivo analysis of near-infrared fluorescence.

    Science.gov (United States)

    Kalia, Sunil; Zhao, Jianhua; Zeng, Haishan; McLean, David; Kollias, Nikiforos; Lui, Harvey

    2018-01-01

    Objective measurements of melanin can provide important information for differentiating melanoma from benign pigmented lesions and in assessing pigmentary diseases. Herein, we evaluate near-infrared (NIR) fluorescence as a possible tool to quantify melanin. Various concentrations of in vitro Sepia melanin in tissue phantoms were measured with NIR fluorescence and diffuse reflectance spectroscopy. Similar optic measurements were conducted in vivo on 161 normal human skin sites. Diffuse reflectance spectroscopy was used to quantify the melanin content via Stamatas-Kollias algorithm. At physiologic concentrations, increasing in vitro melanin concentrations demonstrated higher fluorescence that was linearly correlated (R 2  = 0.99, p < .001). At higher concentrations, the fluorescence signal plateaued. A linear relationship was also observed with melanin content in human skin (R 2  = 0.59, p < .001). Comparing the fluorescence and reflectance signals with in vitro and in vivo samples, the estimated melanin concentration in human skin ranged between 0 and 1.25 mg/ml, consistent with previous quantitative studies involving invasive methods. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Thallium-201: Autoradiography in pigmented mice and melanin-binding in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tjaelve, H.; Nilsson, M.; Larsson, B. (Uppsala Univ. (Sweden))

    1982-01-01

    Autoradiography with /sup 201/Tl/sup +/ in C57Bl mice showed a strong labelling of the eye melanin and of pigmented hair follicles. An analysis of the affinity of thallium for pigment from cow eyes indicated a binding to three groups of sites and showed a marked sensitivity to the addition of H/sup +/-ions. The results are consistent with the conception that a binding of thallium occurs to the free carboxyl groups of the melanin and that the structure of the polymer has a marked influence on the affinity. Similar results have previously been obtained with other cations. There was no indication that the strong in vivo affinity of thallium to melanin is due to a more firm binding than for other cations which do not localize on melanin in vivo. Instead, the ability of cations to pass the melanocyte membranes and reach the melanin granules is probably decisive for whether a melanin-binding will take place in vivo. Toxic effects on the eye and epilation are symptoms of thallium intoxication which may be related to its melanin-binding. The fate of /sup 201/Tl/sup +/ in some other tissues is also described and discussed.

  10. Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils

    Science.gov (United States)

    Colleary, Caitlin; Dolocan, Andrei; Gardner, James; Singh, Suresh; Wuttke, Michael; Rabenstein, Renate; Habersetzer, Jörg; Schaal, Stephan; Feseha, Mulugeta; Clemens, Matthew; Jacobs, Bonnie F.; Currano, Ellen D.; Jacobs, Louis L.; Lyng Sylvestersen, Rene; Gabbott, Sarah E.; Vinther, Jakob

    2015-10-01

    In living organisms, color patterns, behavior, and ecology are closely linked. Thus, detection of fossil pigments may permit inferences about important aspects of ancient animal ecology and evolution. Melanin-bearing melanosomes were suggested to preserve as organic residues in exceptionally preserved fossils, retaining distinct morphology that is associated with aspects of original color patterns. Nevertheless, these oblong and spherical structures have also been identified as fossilized bacteria. To date, chemical studies have not directly considered the effects of diagenesis on melanin preservation, and how this may influence its identification. Here we use time-of-flight secondary ion mass spectrometry to identify and chemically characterize melanin in a diverse sample of previously unstudied extant and fossil taxa, including fossils with notably different diagenetic histories and geologic ages. We document signatures consistent with melanin preservation in fossils ranging from feathers, to mammals, to amphibians. Using principal component analyses, we characterize putative mixtures of eumelanin and phaeomelanin in both fossil and extant samples. Surprisingly, both extant and fossil amphibians generally exhibit melanosomes with a mixed eumelanin/phaeomelanin composition rather than pure eumelanin, as assumed previously. We argue that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils. This refutes the hypothesis that such fossil microbodies could be bacteria, and demonstrates that melanin is widely responsible for the organic soft tissue outlines in vertebrates found at exceptional fossil localities, thus allowing for the reconstruction of certain aspects of original pigment patterns.

  11. Sponge-Associated Bacteria Produce Non-cytotoxic Melanin Which Protects Animal Cells from Photo-Toxicity.

    Science.gov (United States)

    Vijayan, Vijitha; Jasmin, Chekidhenkuzhiyil; Anas, Abdulaziz; Parakkaparambil Kuttan, Sreelakshmi; Vinothkumar, Saradavey; Perunninakulath Subrayan, Parameswaran; Nair, Shanta

    2017-09-01

    Melanin is a photo-protective polymer found in many organisms. Our research shows that the bacteria associated with darkly pigmented sponges (Haliclona pigmentifera, Sigmadocia pumila, Fasciospongia cavernosa, Spongia officinalis, and Callyspongia diffusa) secrete non-cytotoxic melanin, with antioxidant activity that protects animal cells from photo-toxicity. Out of 156 bacterial strains screened, 22 produced melanin and these melanin-producing bacteria (MPB) were identified as Vibrio spp., Providencia sp., Bacillus sp., Shewanella sp., Staphylococcus sp., Planococcus sp., Salinococcus sp., and Glutamicibacter sp. Maximum melanin production was exhibited by Vibrio alginolyticus Marine Microbial Reference Facility (MMRF) 534 (50 mg ml -1 ), followed by two isolates of Vibrio harveyi MMRF 535 (40 mg ml -1 ) and MMRF 546 (30 mg ml -1 ). Using pathway inhibition assay and FT-IR spectral analysis, we identified the melanin secreted into the culture medium of MPB as 1,8-dihydroxynaphthalene-melanin. The bacterial melanin was non-cytotoxic to mouse fibroblast L929 cells and brine shrimps up to a concentration of 200 and 500 ppm, respectively. Bacterial melanin showed antioxidant activity at very low concentration (IC 50 -9.0 ppm) and at 50 ppm, melanin protected L929 cells from UV-induced intracellular reactive oxygen stress. Our study proposes sponge-associated bacteria as a potential source of non-cytotoxic melanin with antioxidant potentials.

  12. The acid-catalyzed interaction of melanin with nitrite ions. An EPR investigation

    Directory of Open Access Journals (Sweden)

    Matuszak Zenon

    2015-07-01

    Full Text Available The interaction of synthetic dihydroxyphenylalanine (DOPA melanin (DM with nitrite ions, NO2−, in the pH 3.6–7.0 range, has been investigated using electron paramagnetic resonance (EPR. We found that especially at pH <5.5 (from ca. 5.5 to 3.6 the reaction of DM with nitrite generated large quantities of new melanin radicals, which implies the involvement of nitrous acid, HNO2, in the radical formation process. Measurements carried out at constant pH of 3.6 showed that the melanin signal increased together with nitrite concentration, reaching a plateau level which was more than fourfold larger compared to the initial signal amplitude observed in a nitrite-free buffer of the same pH. The effects of nitrite and DM concentrations on the melanin-free radical content were also investigated. It is proposed that the radicals are generated by one electron oxidation of melanin ortho-hydroquinone groups to ortho-semiquinones by HNO2 or related nitrogen oxides such as NO2• radicals. The possible involvement of nitric oxide (•NO and peroxynitrite (ONOO− in DM oxidation was also examined. In air-free solutions, nitric oxide per se did not generate melanin radicals; however, in the presence of oxygen a marked increase in the melanin EPR signal intensity was observed. This result is interpreted in terms of the generation of radicals via the oxidation of DM by peroxynitrite. Our findings suggest that melanin can function as a natural scavenger of nitrous acid and some nitrous acid-derived species. This property may be relevant to physiological functions of melanin pigments in vivo.

  13. Melanin concentration gradients in modern and fossil feathers.

    Directory of Open Access Journals (Sweden)

    Daniel J Field

    Full Text Available In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ∼55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly related groups that share aquatic ecologies (e.g. waterfowl Anseriformes, penguins Sphenisciformes, suggesting a potential adaptive function with ancient origins.

  14. Screening of micro-organisms for decolorization of melanins produced by bluestain fungi.

    Science.gov (United States)

    Rättö, M; Chatani, M; Ritschkoff, A C; Viikari, L

    2001-03-01

    A total of 17 fungi and four bacteria were screened for their ability to decolorize melanin, using isolated extracellular melanin of the bluestain fungus Aureobasidium pullulans as substrate. On agar media, decolorization was observed by four fungal strains: Bjerkandera adusta VTT-D-99746, Galactomyces geotrichum VTT-D-84228, Trametes hirsuta VTT-D-95443 and Trametes versicolor VTT-D-99747. The four fungi were more efficient on nitrogen-limited medium than on complete medium. The melanin-decolorizing activity of G. geotrichum appeared to be located on the mycelium and could be liberated into the medium enzymatically.

  15. An objective assessment of melanin in vitiligo skin treated with Balneo PUVA therapy.

    Science.gov (United States)

    Hegyi, V; Petrovajová, M; Novotný, M

    2014-02-01

    Visual clinical methods of skin color evaluation for diagnostic purposes are so far mostly subjective and thus inaccurate. We present a modified method of melanin amount measurement based on diffuse reflectance spectroscopy (DRS). This method is non-invasive and objective, and allows easy quantification and comparison of melanin levels. Skin pigmentation was measured by DRS method in 0-18 year old patients at the Department of Pediatric Dermatovenerology, School of Medicine Comenius University Bratislava. Patients were treated for their vitiligo by Balneo PUVA treatment twice weekly. Each patient had measured his remittance spectra from the treated vitiliginous skin before the treatment was started, after 10 irradiations of Balneo PUVA and at the end of the treatment after 25 irradiations of Balneo PUVA. In our study as a reference skin for spectroscopic assessment of melanin in vivo was used the averaged remittance spectra (measured on the inner arm) from the sample of 10 albino patients. The remittance spectra obtained from the vitiligo patients were ratioed against the newly described remittance reference albino skin. We exploited the linear behavior of the spectral curve in the 620-720 nm interval (significant for melanin absorption) and used the slope of the regression line to compute the quantification index α. By clinical examination before the Balneo PUVA therapy, after the 10th dose of Balneo PUVA therapy as well as at the end of the complete course of Balneo PUVA therapy (after 25 irradiations) we recorded a marked increase of pigmentation in all treated patients for their vitiligo. In each patient the values of melanin quantification angle α were calculated. Statistically we found a significant difference between the melanin quantification angle α in vitiliginous skin before, during the 10th dose of treatment and after the treatment. Similar significant difference was also observed between treated and non-involved skin. We could confirm a clear

  16. The role of alpha-synuclein in melanin synthesis in melanoma and dopaminergic neuronal cells.

    Directory of Open Access Journals (Sweden)

    Tianhong Pan

    Full Text Available The relatively high co-occurrence of Parkinson's disease (PD and melanoma has been established by a large number of epidemiological studies. However, a clear biological explanation for this finding is still lacking. Ultra-violet radiation (UVR-induced skin melanin synthesis is a defense mechanism against UVR-induced damage relevant to the initiation of melanoma, whereas, increased neuromelanin (NM, the melanin synthesized in dopaminergic neurons, may enhance the susceptibility to oxidative stress-induced neuronal injury relevant to PD. SNCA is a PD-causing gene coding for alpha-Synuclein (α-Syn that expresses not only in brain, but also in skin as well as in tumors, such as melanoma. The findings that α-Syn can interact with tyrosinase (TYR and inhibit tyrosine hydroxylase (TH, both of which are enzymes involved in the biosynthesis of melanin and dopamine (DA, led us to propose that α-Syn may participate in the regulation of melanin synthesis. In this study, by applying ultraviolet B (UVB light, a physiologically relevant stimulus of melanogenesis, we detected melanin synthesis in A375 and SK-MEL-28 melanoma cells and in SH-SY5Y and PC12 dopaminergic neuronal cells and determined effects of α-Syn on melanin synthesis. Our results showed that UVB light exposure increased melanin synthesis in all 4 cell lines. However, we found that α-Syn expression reduced UVB light-induced increase of melanin synthesis and that melanin content was lower when melanoma cells were expressed with α-Syn, indicating that α-Syn may have inhibitory effects on melanin synthesis in melanoma cells. Different from melanoma cells, the melanin content was higher in α-Syn-over-expressed dopaminergic neuronal SH-SY5Y and PC12 cells, cellular models of PD, than that in non-α-Syn-expressed control cells. We concluded that α-Syn could be one of the points responsible for the positive association between PD and melanoma via its differential roles in melanin synthesis in

  17. Blood Supply--Susceptible Formation of Melanin Pigment in Hair Bulb Melanocytes of Mice

    Directory of Open Access Journals (Sweden)

    Shogo Maeda, MD

    2015-03-01

    Conclusions: Melanin pigment formation in the hair bulb melanocytes appeared to be susceptible to the blood supply, and melanocytosis was promoted in the follicles and in the epidermis of Kitl-Tg C57BL/6 mice.

  18. Mechanisms of branching reactions in melanin formation - Ab initio quantum engineering approach -

    Science.gov (United States)

    Kishida, Ryo; Menez Aspera, Susan; Kasai, Hideaki

    Melanin, a pigment found in animals, consists of two types of oligomeric unit: eumelanin and pheomelanin. The color of the skin, the hair, and the eyes is controlled by the ratio of eumelanin/pheomelanin production. Especially, dopachrome and dopaquinone are the precursor molecules of melanin which directly affect the composition of melanin through their branching reactions. Dopachrome is converted into two possible monomers of eumelanin. Dopaquinone can undergo both eumelanin and pheomelanin synthesis. To understand the mechanisms and controlling factors that govern the conversions, reactions of the two molecules are investigated using density functional theory-based first-principles calculations. Our results deepen mechanistic understanding of the reactions and open possibilities to design properties and functions of melanin. In this talk, we will discuss about the competitions of the branching reactions.

  19. Screening of Auricularia auricula strains for strong production ability of melanin pigments

    Directory of Open Access Journals (Sweden)

    Yu ZOU

    Full Text Available Abstract Melanin pigments have great application value and development potential in food industry to use as nature functional food colorants. In initial study, twenty-two Auricularia auricula strains were screened for stronger production ability of melanin pigments by solid culture. Three A. auricula strains (RF201, QD2 and QD6 with higher pigment production capacity were selected for further study through submerged culture supplementing 1 g/L l-tyrosine. The maximal pigment yields of A. auricula RF201, QD2 and QD6 were 493.9, 367.6 and 318.5 mg/L, respectively. Among three strains, A. auricula RF201 possessed the strongest production ability of melanin pigments. The present study indicated that A. auricula RF201 could be used as potential excellent producer of melanin pigments.

  20. Gamma-resonance study of the reaction of iron ions with synthetic L-dopa melanin

    Energy Technology Data Exchange (ETDEWEB)

    Bagirov, R.M.; Stukan, R.A.; Lapina, V.A.; Dontsov, A.E.; Ostrovskii, M.A.

    1986-07-01

    The reaction of Fe/sup 3 +/ and Fe/sup 2 +/ ions with synthetic L-dopa melanin, which is a model compound of natural melanin (the melanoprotein granules in the pigment epithelial cells in vertebrate and human eyes), has been studied by gamma-resonance spectroscopy. The investigations showed that L-dopa melanin is capable of effectively binding iron ions and that it displays oxidative or reducing properties with respect to Fe, depending on the composition of the subsystem of the Fe ions and the ambient pH. Trivalent Fe/sup 3 +/ ions form stronger complexes with L-dopa melanin than do Fe/sup 2 +/ ions. The coordination takes place mainly with the carboxyl groups and the amino and imino groups of the polymer. The conformational state of the polymer apparently changes as the pH is varied.

  1. Flux pinning mechanism and Hc2-anisotropy in melanin doped bulk MgB2

    Science.gov (United States)

    Shahabuddin Shah, M.; Shahabuddin, Mohammed; Alzayed, Nasser S.; Parakkandy, Jafar M.

    2014-06-01

    Flux pinning mechanism in melanin doped MgB2 superconductor has been studied using a scaling law proposed by Dew-Hughes and another method proposed by Eisterer. Our experimental data could be fitted very closely by the aforementioned scaling law. The fitting parameters, the positions of peaks bpeak and k = bpeak/bn confirm a grain-boundary pinning in the 10% melanin doped sample, while the undoped sample consists of mixed pinning. Furthermore, percolation theory was utilized under grain-boundary approximation to investigate the role of Hc2-anisotropy in the critical current density, and its dependence on applied field as well as temperature. The Hc2-anisotropy decreases with melanin doping resulting in the increase of Jc in high field. There is suppression of flux pinning maximum due to melanin doping, which is found to be the main reason for the degradation of low-field Jc.

  2. Corticosterone mediates the condition-dependent component of melanin-based coloration

    Czech Academy of Sciences Publication Activity Database

    Roulin, A.; Almasi, B.; Rossi-Pedruzzi, A.; Ducrest, A.-L.; Wakamatsu, K.; Mikšík, Ivan; Blount, J.D.; Jenni-Eiermann, S.; Jenni, L.

    2008-01-01

    Roč. 75, č. 4 (2008), s. 1351-1358 ISSN 0003-3472 Institutional research plan: CEZ:AV0Z50110509 Keywords : coricosterone * barn owl * melanin Subject RIV: CE - Biochemistry Impact factor: 2.828, year: 2008

  3. Lasers in esthetic treatment of gingival melanin hyperpigmentation: a review article.

    Science.gov (United States)

    Bakhshi, Mahin; Rahmani, Somayeh; Rahmani, Ali

    2015-11-01

    The health and suitability of mouth components play an important role towards defining facial attractiveness. An important component of the oral cavity is the color of the gingival tissue. Gingival melanin hyperpigmentation is caused by several reasons and affects people across ethnicity, race, age, and both gender. Lasers are presently being used for gingival melanin depigmentation. In this article, we reviewed studies on laser parameters, duration of gingival healing, pain perception during and after the operation, scores used for the evaluation of gingival melanin hyperpigmentation, follow-up period, treatment results, and recurrence reports. We conclude that laser ablation for gingival depigmentation is one of the most pleasant, reliable, acceptable, and impressive techniques available for treating gingival melanin hyperpigmentation.

  4. The role of melanin as protector against free radicals in skin and its role as free radical indicator in hair

    Science.gov (United States)

    Herrling, Thomas; Jung, Katinka; Fuchs, Jürgen

    2008-05-01

    Throughout the body, melanin is a homogenous biological polymer containing a population of intrinsic, semiquinone-like radicals. Additional extrinsic free radicals are reversibly photo-generated by UV and visible light. Melanin photochemistry, particularly the formation and decay of extrinsic radicals, has been the subject of numerous electron spin resonance (ESR) spectroscopy studies. Several melanin monomers exist, and the predominant monomer in a melanin polymer depends on its location within an organism. In skin and hair, melanin differs in content of eumelanin or pheomelanin. Its bioradical character and its susceptibility to UV irradiation makes melanin an excellent indicator for UV-related processes in both skin and hair. The existence of melanin in skin is strongly correlated with the prevention against free radicals/ROS generated by UV radiation. Especially in the skin melanin (mainly eumelanin) ensures the only natural UV protection by eliminating the generated free radicals/ROS. Melanin in hair can be used as a free radical detector for evaluating the efficacy of hair care products. The aim of this study was to investigate the suitability of melanin as protector of skin against UV generated free radicals and as free radical indicator in hair.

  5. Examination by EPR spectroscopy of free radicals in melanins isolated from A-375 cells exposed on valproic acid and cisplatin.

    Science.gov (United States)

    Chodurek, Ewa; Zdybel, Magdalena; Pilawa, Barbara; Dzierzewicz, Zofia

    2012-01-01

    Drug binding by melanin biopolymers influence the effectiveness of the chemotherapy, radiotherapy and photodynamic therapy. Free radicals of melanins take part in formation of their complex with drugs. The aim of this work was to determine the effect of the two compounds: valproic acid (VPA) and cisplatin (CPT) on free radicals properties of melanin isolated from A-375 melanoma cells. Free radicals were examined by an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. EPR spectra were measured for the model synthetic eumelanin - DOPA-melanin, the melanin isolated from the control A-375 cells and these cells treated by VPA, CPT and both VPA and CPT. For all the examined samples broad EPR lines (deltaBpp: 0.48-0.68 mT) with g-factors of 2.0045-2.0060 characteristic for o-semiquinone free radicals were observed. Free radicals concentrations (N) in the tested samples, g-factors, amplitudes (A), integral intensities (I) and linewidths (deltaBpp) of the EPR spectra, were analyzed. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR spectra indicated that slow spin-lattice relaxation processes existed in all the tested melanin samples. The relatively slowest spin-lattice relaxation processes characterized melanin isolated from A-375 cells treated with both VPA and CPT. The changes of the EPR spectra with increasing microwave power in the range of 2.2-70 mW were evaluated. Free radicals concentrations in the melanin from A-375 cells were higher than in the synthetic DOPA-melanin. The strong increase of free radicals concentration in the melanin from A-375 cells was observed after their treating by VPA. CPT also caused the increase of free radicals concentrations in the examined natural melanin. The free radicals concentration in melanin isolated from A-375 cells treated with both VPA and CPT was slightly higher than those in melanin from the control cells.

  6. Melanin in human irides of different color and age of donors.

    Science.gov (United States)

    Wielgus, Albert R; Sarna, Tadeusz

    2005-12-01

    Melanin is the main chromophore of the human iris. This pigment is considered to be the most important factor that determines the color of the irides. Previous studies based mainly on chemical degradation methods showed that brown irides contain more melanin than blue ones. In our study, we used electron spin resonance (ESR) spectroscopy to detect and characterize melanin free radical centers and associated iron in human irides. Based on this method, we determined the amount of melanin in the irides and the relative content of iron in iridial melanin as a function of their color, shade, and the age of their donors. Chemical degradation of iridial homogenates enabled us to characterize the structure of eumelanin and determine the content of pheomelanin present in human and bovine irides. The ESR amplitude, the normalized intensity obtained by double integration of the ESR signal of melanin, and the content of the pigment in the irides depended on color and shade of the eyes being 40% higher in the brown group of the irides compared with all other groups. On the other hand, the relative iron content normalized to the melanin content in light blue irides showed a small decrease with age of donors. Melanin in human and bovine irides was mostly composed of eumelanin, and pheomelanin content was of the order of a few percent. Although some differences in the structure of eumelanin present in the human and bovine irides are possible, the results obtained in this study suggest that human irides contain eumelanin with very similar chemical properties.

  7. Tyrisonase inhibition and melanin reduction of human melanocytes (HEMn-MP) using Anacardium occidentale L extract.

    Science.gov (United States)

    Abdul Gaffar, R; Abdul Majid, F A; Sarmidi, M R

    2008-07-01

    Cashew (Anacardium occindentale L) leaves extract (CLE) has potential as tyrosinase inhibitor that can be used for therapeutic in pigmentation problem. This study investigates the real potential of CLE to inhibit tyrosinase and melanin reduction using human epidermal melanocytes. The extracts were exposed to the human melanocytes for more than 24 hours. The CLE extract exhibited potential as tyrosinase inhibitor, reduced melanin and high in antioxidant activity relative to commercial extract of Emblica sp.

  8. Andrographolide suppresses melanin synthesis through Akt/GSK3β/β-catenin signal pathway.

    Science.gov (United States)

    Zhu, Ping-Ya; Yin, Wei-Han; Wang, Meng-Ran; Dang, Yong-Yan; Ye, Xi-Yun

    2015-07-01

    Tyrosinase (TYR) is the key enzyme controlling the production of melanin. Very few papers have reported that andrographolide can inhibit melanin content. To investigate the effects of andrographolide on melanin synthesis. Cell viability, melanin content, TYR activity, transcriptional and protein expression levels of TYR family and other kinds of proteins involved in melanogenesis were measured after the treatments of andrographolide. It was found that andrographolide decreased melanin content, TYR activity and transcriptional and protein expression of TYR family and microphthalmia-associated transcription factor (MITF) in B16F10 melanoma cells. Data showed andrographolide also decreased melanin content and TYR content in ultraviolet B (UVB) irradiation induced brown guinea pigs. Moreover, we found that melanin content and TYR activity were effectively inhibited in Human Epidermis Melanocyte (HEM) treated with andrographolide at the medium concentrations without apparent effect on cell viability. Results in experiments treated with MG-132 or cycloheximide (CHX) showed that andrographolide lowered the content of β-catenin in cell nucleus resulting from accelerating the degradation of β-catenin. Phosphorylation of glycogen synthase kinase 3β (GSK3β) and Akt decreased simultaneously. 6-Bromoindirubin-3'-oxime (BIO, inhibitor of GSK3β) and insulin-like growth factors-1 (IGF-1, activator of Akt) could reverse the decline of β-catenin in B16F10 cells induced by andrographolide. These results demonstrate that andrographolide can effectively suppress melanin content and TYR activity in B16F10 cells, HEM cells and UVB-induced brown guinea pig skin by decreasing phosphorylation of GSK3β dependent on Akt, promoting the degradation of β-catenin, inhibiting β-catenin into the nucleus and decreasing the expression of MITF and TYR family. Data indicate that andrographolide may be a potential whiting agent which can have great market in cosmetics and in clinical such as

  9. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    OpenAIRE

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Ro, Hyunju; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in ? -melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respect...

  10. Screening of Auricularia auricula strains for strong production ability of melanin pigments

    OpenAIRE

    ZOU, Yu; MA, Kun

    2017-01-01

    Abstract Melanin pigments have great application value and development potential in food industry to use as nature functional food colorants. In initial study, twenty-two Auricularia auricula strains were screened for stronger production ability of melanin pigments by solid culture. Three A. auricula strains (RF201, QD2 and QD6) with higher pigment production capacity were selected for further study through submerged culture supplementing 1 g/L l-tyrosine. The maximal pigment yields of A. aur...

  11. Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica, its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown and belly (white-to-brownish feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations

  12. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Directory of Open Access Journals (Sweden)

    Aulie Banerjee

    Full Text Available Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13C NMR, we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  13. Redox Active Transition Metal ions Make Melanin Susceptible to Chemical Degradation Induced by Organic Peroxide.

    Science.gov (United States)

    Zadlo, Andrzej; Pilat, Anna; Sarna, Michal; Pawlak, Anna; Sarna, Tadeusz

    2017-12-01

    With aging, retinal pigment epithelium melanosomes, by fusion with the age pigment lipofuscin, form complex granules called melanolipofuscin. Lipofuscin granules may contain oxidized proteins and lipid hydroperoxides, which in melanolipofuscin could chemically modify melanin polymer, while transition metal ions present in melanin can accelerate such oxidative modifications. The aim of this research was to examine the effect of selected transition metal ions on melanin susceptibility to chemical modification induced by the water-soluble tert-butyl hydroperoxide used as an oxidizing agent. Synthetic melanin obtained by DOPA autooxidation and melanosomes isolated from bovine retinal pigment epithelium were analyzed. To monitor tert-butyl hydroperoxide-induced oxidative changes of DMa and BMs, electron paramagnetic resonance spectroscopy, UV-vis absorption spectroscopy, dynamic light scattering, atomic force microscopy and electron paramagnetic resonance oximetry were employed. These measurements revealed that both copper and iron ions accelerated chemical degradation induced by tert-butyl hydroperoxide, while zinc ions had no effect. Strong prooxidant action was detected only in the case of melanosomes and melanin degraded in the presence of iron. It can be postulated that similar chemical processes, if they occur in situ in melanolipofuscin granules of the human retinal pigment epithelium, would modify antioxidant properties of melanin and its reactivity.

  14. Purification and physiochemical characterization of melanin pigment from Klebsiella sp. GSK.

    Science.gov (United States)

    Sajjan, Shrishailnath; Kulkarni, Guruprasad; Yaligara, Veeranagouda; Kyoung, Lee; Karegoudar, T B

    2010-11-01

    The bacterium capable of producing melanin pigment in the presence of L-tyrosine was isolated from crop field soil sample and identified as Klebsiella sp. GSK based on morphological, biochemical and 16S rDNA sequencing. The polymerization of this pigment occurs outside the cell wall, which has granular structure as melanin ghosts. The chemical characterization of pigment particles showed acid resistant, alkali soluble, insoluble in most of the organic solvents and water. The pigment gets bleached when subjected to the action of oxidants as well as reductants. This pigment was precipitated with FeCl3, ammoniacal silver nitrate and potassium ferricynide. The pigment showed high absorbance in the UV region and decreased absorbance when shifted towards the visible region. The melanin pigment was further charecterized by FT-IR and EPR spectroscopy. A key enzyme 4-hydroxyphenylacetic acid hydroxylase catalyzes the formation of melanin pigment by hydroxylation of L-tyrosine was detected in this bacterium. Inhibition studies with specific inhibitor kojic acid and KCN proved that melanin is synthesized by DOPA-Melanin pathway.

  15. Tyrosinase-catalyzed melanin as a contrast agent for photoacoustic tomography

    Science.gov (United States)

    Krumholz, Arie; Chavez, Sarah; Yao, Junjie; Fleming, Timothy; Gillanders, William E.; Wang, Lihong V.

    2011-03-01

    It is difficult to distinguish between tumor cells and surrounding cells without staining as is done in histology. We developed tyrosinase-catalyzed melanin as a reporter gene for photoacoustic tomography. Tyrosinase is the primary enzyme responsible for the production of melanin and alone is sufficient to produce melanin in non-melanogenic cells. Two cell lines were created: a stably transfected HeLa line and a transiently transfected 293 line. A phantom experiment was performed with the 293 transfected cells 48 hours post transfection and the results compared with oxygenated whole blood, B16 melanoma and 293 control cells. An in vivo experiment was performed using the transfected HeLa cells xenografted into a nude mouse ear, and then imaged. The results show strong contrast for tyrosinase-catalyzed melanin in both the 293 cells in the tube phantom as well as the in vivo result showing melanin in a nude mouse ear. Transfection increased expression in 293 cells 159 fold and image contrast compared to blood by as much as 50 fold. Due to the strong signal obtained at longer wavelengths and the decrease of blood signal at the same wavelengths, tyrosinase catalyzed melanin is a good candidate as a molecular imaging contrast agent for photoacoustic tomography.

  16. Efektivitas kurkumin sebagai antioksidan dan inhibitor melanin pada kultur sel B16F1

    Directory of Open Access Journals (Sweden)

    Sugiharto Sugiharto

    2013-03-01

    Full Text Available Melanin inhibitors have become increasingly important ingredients in medication and cosmetics for the prevention ofhyperpigmentation. In the last few years, a huge number of natural herbal extracts have been tested as inhibitors of melanin synthesisand some of these effects are related to the antioxidant properties. The objectives of this study were to determine of curcumin propertiesas antioxidant activity and melanin inhibitors. In this study, our data indicated that antioxidant assay with DPPH showed IC50 was16,05 μg/ml. In the absence of α-MSH (α-Melanocyte Stimulating Hormone, melanin content assay in cell B16-F1 indicated thatthe highest activity of curcumin to reduce melanin content of 45,67% at 25 μg/ml. Meanwhile, in the presence of α-MSH at the sameconcentration indicated that the highest activity was 53,87%. Based on the data, curcumin has potential properties as antioxidantactivity and melanin inhibitor.

  17. Variation of Human Hairiness: A Possible Adaptation to Solar Radiation and Melanin

    Directory of Open Access Journals (Sweden)

    Dhugga Amrita

    2014-07-01

    Full Text Available Many theories have been advanced to explain human hairlessness, however, there is no consensus. This study of 76 males observed that skin reflectance measuring skin colouration and melanin pigmentation correlated with hair size and follicle density. Individuals with a greater concentration of melanin within the superficial layer of the skin had a lower follicle density and smaller sizes of hairs. In contrast, individuals with a lower melanin concentration and lighter skin colour had a full range of hairiness. This leads to the suggestion that over the course of human evolution, high concentrations of melanin in consistently exposed to ultraviolet radiation areas developed first and that hair loss was a consequence of competition in the skin between melanin production and hair growth. Darker pigmented skin and lower follicle density are significantly correlated (R2=0.283; p<0.05. Individuals with darker skin had a mean of 4.91 follicles per cm2 whereas those with lighter skin reflectance had 11.20 follicles per cm2. This suggests that increased concentrations of melanin in the basal layer of the epidermis may limit hairiness by negatively influencing the skin's ability to produce hair.

  18. Influence of melanin on mutation load in Drosophila populations after long-term irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mosse, I.B.; Lyakh, I.P. [Belarus Academy of Sciences, Minsk (Belarus)

    1994-09-01

    The effect of melanin on the level of mutation load has been studied in experimental Drosophila populations exposed to radiation for 115 generations. Four types of populations have been analyzed: (1) control; (2) treated with melanin; (3) irradiated; (4) irradiated and treated with melanin. Melanin was produced by auto-oxidation of 1-dioxyphenylallanine and was constantly added to food. Populations were X-irradiated twice in each generation (at the larvae stage with 6 Gy and at the imago stage with 9 Gy). The level of recessive mutation on the third chromosome was analyzed by a standard genetic method of balanced lethals. The data obtained have shown that the populations exposed to long-term irradiation have the greatest number of mutations decreasing viability. Melanin exhibited radioprotective properties-it reduced the percentage of lethal, semilethal and subvital mutations. Thus the possibility of effective protection of populations exposed to radiation for many generations by melanin has been shown for the first time. 19 refs., 1 fig., 1 tab.

  19. The interaction of melanin with ionizing and UVC radiations: Characterization of thymine damage

    Energy Technology Data Exchange (ETDEWEB)

    Huselton, C.A.

    1988-01-01

    These studies were undertaken to determine whether melanin could protect DNA against the harmful effects of ionizing or UVC radiations. A simple, in vitro, model system was developed to evaluate eumelanin (Sigma melanin) as a radioprotector of solutions of 0.1 mM thymine or thymidine exposed to 570Gy of ionizing radiation. Sigma melanin was compared to several amino acids, other biomolecules or to other forms of melanin. To investigate the role of melanin as a passive screen of UVC radiation, melanotic (I{sub 3}), amelanotic (AMEL) cells (both derived from a Cloudman S91 melanoma) and non-melanotic (EMT6) cells were labelled with radioactive dTHd and exposed to 0, 1, 5 or 10KJ/m{sup 2} of UVC. The DNA was extracted; the bases hydrolyzed with concentrated HCl. Thymine bases were separated by reverse phase HPLC. No difference in dimer content was observed between I{sub 3} and AMEL cells, but EMT6 cells had nearly twice the amount of dimer. Overall thymine degradation was more pronounced in I{sub 3} cells than in the other two cell lines, due to the production of non-dimer thymine damage. This damage was identified as thymine glycol by HPLC and mass spectrometry. Melanin, upon exposure to UVC, appears to enhance thymine damage by producing oxidative damage.

  20. Melanin-independent accumulation of turgor pressure in appressoria of Phakopsora pachyrhizi.

    Science.gov (United States)

    Chang, Hao-Xun; Miller, Lou Ann; Hartman, Glen L

    2014-09-01

    Appressoria of some plant-pathogenic fungi accumulate turgor pressure that produces a mechanical force enabling the direct penetration of hyphae through the epidermis. Melanin functions as an impermeable barrier to osmolytes, which allows appressoria to accumulate high turgor pressure. Deficiency of melanin in appressoria reduces turgor pressure and compromises the infection process. In Phakopsora pachyrhizi, the soybean rust pathogen, the appressoria are hyaline. Our objective was to ensure the absence of a melanin layer specifically between the appressorial cell wall and plasma membrane, as well as to determine the turgor pressure of P. pachyrhizi appressoria. We demonstrated that two melanin biosynthesis inhibitors neither reduced turgor pressure nor compromised the infection process. Transmission electron microscopy also showed the absence of a melanin layer between the appressorial cell wall and plasma membrane. In addition, the turgor pressure of P. pachyrhizi appressoria was 5 to 6 MPa, based on extracellular osmolytes used to simulate different osmotic pressures. This is the first report showing that turgor pressure accumulation of P. pachyrhizi appressoria was independent of melanin.

  1. Melanins in Fossil Animals: Is It Possible to Infer Life History Traits from the Coloration of Extinct Species?

    OpenAIRE

    Negro, Juan J.; Fynlayson, Clive; Galván, Ismael

    2018-01-01

    Paleo-colour scientists have recently made the transition from describing melanin-based colouration in fossil specimens to inferring life-history traits of the species involved. Two such cases correspond to counter-shaded dinosaurs: dark-coloured due to melanins dorsally, and light-coloured ventrally. We believe that colour reconstruction of fossils based on the shape of preserved microstructures—the majority of paleo-colour studies involve melanin granules—is not without risks. In addition, ...

  2. Melanin-concentrating hormone (MCH: a new sleep factor?

    Directory of Open Access Journals (Sweden)

    Pablo eTorterolo

    2011-03-01

    Full Text Available Neurons that utilize the neuropeptide melanin-concentrating hormone (MCH as a neuromodulator are mainly located in the lateral hypothalamus and the incerto-hypothalamic area, and have widespread projections throughout the brain. While the biological functions of this neuropeptide are exerted in humans through two metabotropic receptors, the MCHR1 and MCHR2, only the MCHR1 is present in rodents. Recently, it has been shown that the MCHergic system is involved in the control of sleep. We can summarize the experimental findings as follows:1. The areas related to the control of sleep and wakefulness have an important density of MCHergic fibers and receptors.2. MCHergic neurons are active during sleep, especially during REM sleep.3. Genetically-modified animals without MCH have less REM sleep, notably under conditions of negative energy balance. 4. Systemically administered MCHR1 antagonists reduce sleep. 5. Intraventricular microinjection of MCH increases both slow wave sleep (SWS and REM sleep; however, the increment in REM sleep is more pronounced.6. Microinjection of MCH into the dorsal raphe nucleus increases REM sleep time. REM seep is inhibited by immunoneutralization of MCH within this nucleus.7. Microinjection of MCH in the nucleus pontis oralis of the cat enhances REM sleep time and reduces REM sleep latency.All these data strongly suggest that MCH has a potent role in the promotion of sleep. Although both SWS and REM sleep are facilitated by MCH, REM sleep seems to be more sensitive to MCH modulation.

  3. Melanin concentrating hormone modulates oxytocin-mediated marble burying.

    Science.gov (United States)

    Sanathara, Nayna M; Garau, Celia; Alachkar, Amal; Wang, Lien; Wang, Zhiwei; Nishimori, Katsuhiko; Xu, Xiangmin; Civelli, Olivier

    2018-01-01

    Repetitive and perseverative behaviors are common features of a number of neuropsychiatric diseases such as Angelman's syndrome, Tourette's syndrome, obsessive-compulsive disorder, and autism spectrum disorders. The oxytocin system has been linked to the regulation of repetitive behavior in both animal models and humans, but many of its downstream targets have still to be found. We report that the melanin-concentrating hormone (MCH) system is a target of the oxytocin system in regulating one repetitive behavior, marble burying. First we report that nearly 60% of MCH neurons express oxytocin receptors, and demonstrate using rabies mediated tract tracing that MCH neurons receive direct presynaptic input from oxytocin neurons. Then we show that MCH receptor knockout (MCHR1KO) mice and MCH ablated animals display increased marble burying response while central MCH infusion decreases it. Finally, we demonstrate the downstream role of the MCH system on oxytocin mediated marble burying by showing that central infusions of MCH and oxytocin alone or together reduce it while antagonizing the MCH system blocks oxytocin-mediated reduction of this behavior. Our findings reveal a novel role for the MCH system as a mediator of the role of oxytocin in regulating marble-burying behavior in mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Memory-like behavior as a feature of electrical signal transmission in melanin-like bio-polymers

    Science.gov (United States)

    Ambrico, M.; Ambrico, P. F.; Ligonzo, T.; Cardone, A.; Cicco, S. R.; Lavizzera, A.; Augelli, V.; Farinola, G. M.

    2012-06-01

    The memory-like behavior of melanin biopolymer under electrical stimuli is shown through electrical transport characterization performed on melanin based metal insulator semiconductor structures on silicon. The presence of a memory window and retention behavior is verified by capacitance-voltage read outs before and after the application of voltage pulses. Interestingly, these phenomena occur without the presence of metallic nanoclusters enclosed in the melanin matrix. Charge trapping is considered the main mechanism responsible for the melanin memory-like character. The inability to erase the memory window has been ascribed to the permanent polarization effect during the application of the voltage pulse.

  5. Physiological oral melanin pigmentation in a South African sample: A clinical study.

    Science.gov (United States)

    Masilana, Aubrey; Khammissa, Razia A G; Lemmer, Johan; Feller, Liviu

    2017-11-01

    Physiological oral melanin pigmentation is genetically determined, more frequently affecting people with darker skin. It can involve any oral mucosal site, but predominantly the gingiva. The aim of the present study was to determine the prevalence and to characterize the clinical features of physiological oral melanin pigmentation in a South African population sample. A trainee in the discipline of periodontology and oral medicine interviewed all participants and examined the oral soft tissues. The diagnosis of physiological oral melanin pigmentation was based on clinical findings and on the history reported by the patient. A predetermined list of exclusion criteria was applied. The study population comprised 430 participants, of whom 319 (74%) were black, 55 (13%) Indian, 54 (12.5%) white, and two (0.5%) were mixed race. A total of 182 participants were diagnosed with physiological oral melanin pigmentation. The overall prevalence of physiological oral melanin pigmentation in the ethnically-mixed study population was 42%: 54% of blacks were affected, 16% of Indians, and 21% of whites. The female (101): male (81) ratio was 1.2:1; the gingiva was the site most frequently affected (73%). The total number of oral mucosal sites with physiological oral melanin pigmentation in the study population was 263; 68% of participants had one, 22% had two, 7% had three, and 3% had four sites affected. There was no significant association between the number of sites affected and sex or age. In this study of a South African population sample, the prevalence of physiological oral melanin pigmentation was higher in blacks than in Indians or whites, and the gingiva was the oral mucosal site most frequently affected. © 2017 John Wiley & Sons Australia, Ltd.

  6. E-cadherin mediates ultraviolet radiation- and calcium-induced melanin transfer in human skin cells.

    Science.gov (United States)

    Singh, Suman K; Baker, Richard; Sikkink, Stephen K; Nizard, Carine; Schnebert, Sylvianne; Kurfurst, Robin; Tobin, Desmond J

    2017-11-01

    Skin pigmentation is directed by epidermal melanin units, characterized by long-lived and dendritic epidermal melanocytes (MC) that interact with viable keratinocytes (KC) to contribute melanin to the epidermis. Previously, we reported that MC:KC contact is required for melanosome transfer that can be enhanced by filopodi, and by UVR/UVA irradiation, which can upregulate melanosome transfer via Myosin X-mediated control of MC filopodia. Both MC and KC express Ca 2+ -dependent E-cadherins. These homophilic adhesion contacts induce transient increases in intra-KC Ca 2+ , while ultraviolet radiation (UVR) raises intra-MC Ca 2+ via calcium-selective ORAI1 ion channels; both are associated with regulating melanogenesis. However, how Ca 2+ triggers melanin transfer remains unclear. Here we evaluated the role of E-cadherin in UVR-mediated melanin transfer in human skin cells. MC and KC in human epidermis variably express filopodia-associated E-cadherin, Cdc42, VASP and β-catenin, all of which were upregulated by UVR in human MC in vitro. Knockdown of E-cadherin revealed that this cadherin is essential for UVR-induced MC filopodia formation and melanin transfer. Moreover, Ca 2+ induced a dose-dependent increase in filopodia formation and melanin transfer, as well as increased β-catenin, Cdc42, Myosin X and E-cadherin expression in these skin cells. Together, these data suggest that filopodial proteins and E-cadherin, which are upregulated by intracellular (UVR-stimulated) and extracellular Ca 2+ availability, are required for filopodia formation and melanin transfer. This may open new avenues to explore how Ca 2+ signalling influences human pigmentation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Melanin-Like Pigment Synthesis by Soil Bacillus weihenstephanensis Isolates from Northeastern Poland.

    Directory of Open Access Journals (Sweden)

    Justyna M Drewnowska

    Full Text Available Although melanin is known for protecting living organisms from harmful physical and chemical factors, its synthesis is rarely observed among endospore-forming Bacillus cereus sensu lato. Here, for the first time, we reported that psychrotolerant Bacillus weihenstephanensis from Northeastern Poland can produce melanin-like pigment. We assessed physicochemical properties of the pigment and the mechanism of its synthesis in relation to B. weihenstephanensis genotypic and phenotypic characteristics. Electron paramagnetic resonance (EPR spectroscopy displayed a stable free radical signal of the pigment from environmental isolates which are consistent with the commercial melanin. Fourier transform infrared spectroscopy (FT-IR and physicochemical tests indicated the phenolic character of the pigment. Several biochemical tests showed that melanin-like pigment synthesis by B. weihenstephanensis was associated with laccase activity. The presence of the gene encoding laccase was confirmed by the next generation whole genome sequencing of one B. weihenstephanensis strain. Biochemical (API 20E and 50CHB tests and genetic (Multi-locus Sequence Typing, 16S rRNA sequencing, and Pulsed-Field Gel Electrophoresis characterization of the isolates revealed their close relation to the psychrotrophic B. weihenstephanensis DSMZ 11821 reference strain. The ability to synthesize melanin-like pigment by soil B. weihenstephanensis isolates and their psychrotrophic character seemed to be a local adaptation to a specific niche. Detailed genetic and biochemical analyses of melanin-positive environmental B. weihenstephanensis strains shed some light on the evolution and ecological adaptation of these bacteria. Moreover, our study raised new biotechnological possibilities for the use of water-soluble melanin-like pigment naturally produced by B. weihenstephanensis as an alternative to commercial non-soluble pigment.

  8. Melanin-Covered Nanoparticles for Protection of Bone Marrow During Radiation Therapy of Cancer

    International Nuclear Information System (INIS)

    Schweitzer, Andrew D.; Revskaya, Ekaterina; Chu, Peter; Pazo, Valeria; Friedman, Matthew; Nosanchuk, Joshua D.; Cahill, Sean; Frases, Susana; Casadevall, Arturo; Dadachova, Ekaterina

    2010-01-01

    Purpose: Protection of bone marrow against radiotoxicity during radioimmunotherapy and in some cases external beam radiation therapy such as hemi-body irradiation would permit administration of significantly higher doses to tumors, resulting in increased efficacy and safety of treatment. Melanin, a naturally occurring pigment, possesses radioprotective properties. We hypothesized that melanin, which is insoluble, could be delivered to the bone marrow by intravenously administrated melanin-covered nanoparticles (MNs) because of the human body's 'self-sieving' ability, protecting it against ionizing radiation. Methods and Materials: The synthesis of MNs was performed via enzymatic polymerization of 3,4-dihydroxyphenylalanine and/or 5-S-cysteinyl-3,4-dihydroxyphenylalanine on the surface of 20-nm plain silica nanoparticles. The biodistribution of radiolabeled MNs in mice was done at 3 and 24 h. Healthy CD-1 mice (Charles River Laboratories International, Inc., Wilmington, MA) or melanoma tumor-bearing nude mice were given MNs intravenously, 50 mg/kg of body weight, 3 h before either whole-body exposure to 125 cGy or treatment with 1 mCi of 188 Re-labeled 6D2 melanin-binding antibody. Results: Polymerization of melanin precursors on the surface of silica nanoparticles resulted in formation of a 15-nm-thick melanin layer as confirmed by light scattering, transmission electron microscopy, and immunofluorescence. The biodistribution after intravenous administration showed than MN uptake in bone marrow was 0.3% and 0.2% of injected dose per gram at 3 and 24 h, respectively, whereas pre-injection with pluronic acid increased the uptake to 6% and 3% of injected dose per gram, respectively. Systemic MN administration reduced hematologic toxicity in mice treated with external radiation or radioimmunotherapy, whereas no tumor protection by MNs was observed. Conclusions: MNs or similar structures provide a novel approach to protection of bone marrow from ionizing radiation based

  9. Production of melanin pigment from Pseudomonas stutzeri isolated from red seaweed Hypnea musciformis.

    Science.gov (United States)

    Ganesh Kumar, C; Sahu, N; Narender Reddy, G; Prasad, R B N; Nagesh, N; Kamal, A

    2013-10-01

    Hypnea musciformis red seaweed is popularly known to produce carrageenan was collected from the Gulf of Mannar, India. Strain HMGM-7 [MTCC 11712] was isolated from the surface of this seaweed, which was capable of producing an extracellular black-coloured polymeric pigment. Based on phenotypic characterization and 16S rDNA sequencing, the strain HMGM-7 was identified as Pseudomonas stutzeri. Biophysical characterization by UV-visible, FT-IR, EPR and XRD spectroscopic studies confirmed the pigment as melanin. Further chemical characterization showed that it was acid-resistant, alkali-soluble and alkali-insoluble in most of the organic solvents and distilled water. To our knowledge, this is a first report on a marine Pseudomonas stutzeri strain producing significant amounts of melanin of about 6·7 g l(-1) without L-tyrosine supplementation in the sea-water production medium. This investigation reports a marine Pseudomonas stutzeri strain HMGM-7 [MTCC 11712] that produces significant quantities of melanin (6·7 g l(-1) ) in sea-water medium without the supplementation of L-tyrosine. The confirmation of the produced melanin was carried out by various chemical and physical characterization studies. The isolated melanin may find potential application for use in cosmetic and/or pharmaceutical industries. © 2013 The Society for Applied Microbiology.

  10. Melanin pigmentation gives rise to black spots on the wings of the silkworm Bombyx mori.

    Science.gov (United States)

    Ito, Katsuhiko; Yoshikawa, Manabu; Fujii, Takeshi; Tabunoki, Hiroko; Yokoyama, Takeshi

    2016-01-01

    Several mutants of the silkworm Bombyx mori show body color variation at the larval and adult stages. The Wild wing spot (Ws) mutant exhibits a phenotype in which the moth has a spot on the apex of the forewing. In this study, we investigated this trait to elucidate the molecular mechanism underlying the color pattern. Microscopy of the black spot of Ws mutants showed that the pigment emerges in the scales of the wing, and accumulation of the pigment becomes strong just before eclosion. We next examined the relationship between the black spot of the Ws mutant and melanin. The spectrophotometry using alkaline extracts from the black spot in the wing showed the highest absorption intensity at 405nm, which is the absorbance wavelength of melanin. Moreover, inhibition assays for enzymes implicated in melanin synthesis using 3-iodo-l-tyrosine (a tyrosine hydroxylase inhibitor) and L-α-methyl-DOPA (a dopa decarboxylase inhibitor) revealed that treatment with each inhibitor disrupted the pigmentation of the wing of the Ws mutant. On the basis of these results, we analyzed the expression pattern of five genes involved in melanin formation, and found that the expression levels of yellow and laccase2 were increased just before pigmentation, whereas those of DDC, tan, and TH were increased when the apex of the wing turned black. These results showed that melanin pigmentation gives rise to the black spot on the wing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. D-tyrosine negatively regulates melanin synthesis by competitively inhibiting tyrosinase activity.

    Science.gov (United States)

    Park, Jisu; Jung, Hyejung; Kim, Kyuri; Lim, Kyung-Min; Kim, Ji-Young; Jho, Eek-Hoon; Oh, Eok-Soo

    2017-11-09

    Although L-tyrosine is well known for its melanogenic effect, the contribution of D-tyrosine to melanin synthesis was previously unexplored. Here, we reveal that, unlike L-tyrosine, D-tyrosine dose-dependently reduced the melanin contents of human MNT-1 melanoma cells and primary human melanocytes. In addition, 500 μM of D-tyrosine completely inhibited 10 μM L-tyrosine-induced melanogenesis, and both in vitro assays and L-DOPA staining MNT-1 cells showed that tyrosinase activity is reduced by D-tyrosine treatment. Thus, D-tyrosine appears to inhibit L-tyrosine-mediated melanogenesis by competitively inhibiting tyrosinase activity. Furthermore, we found that D-tyrosine inhibited melanogenesis induced by α-MSH treatment or UV irradiation, which are the most common environmental factors responsible for melanin synthesis. Finally, we confirmed that D-tyrosine reduced melanin synthesis in the epidermal basal layer of a 3D human skin model. Taken together, these data suggest that D-tyrosine negatively regulates melanin synthesis by inhibiting tyrosinase activity in melanocyte-derived cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Condition-dependent expression of melanin-based coloration in the Eurasian kestrel

    Science.gov (United States)

    Piault, Romain; van den Brink, Valentijn; Roulin, Alexandre

    2012-05-01

    Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent. Significant costs imposed by an ornament would ensure that only the highest quality individuals display the most exaggerated forms of the signal. Firm evidence that melanin-based traits can be condition-dependent is still rare in birds. In an experimental test of this central assumption, we report condition-dependent expression of a melanin-based trait in the Eurasian kestrel ( Falco tinnunculus). We manipulated nestling body condition by reducing or increasing the number of nestlings soon after hatching. A few days before fledging, we measured the width of sub-terminal black bands on the tail feathers. Compared to nestlings from enlarged broods, individuals raised in reduced broods were in better condition and thereby developed larger sub-terminal bands. Furthermore, in 2 years, first-born nestlings also developed larger sub-terminal bands than their younger siblings that are in poorer condition. This demonstrates that expression of melanin-based traits can be condition-dependent.

  13. Interference of melanin in the susceptibility profile of Sporothrix species to amphotericin B.

    Science.gov (United States)

    Mario, Débora Alves Nunes; Santos, Roberto Christ Vianna; Denardi, Laura Bedin; Vaucher, Rodrigo de Almeida; Santurio, Janio Morais; Alves, Sydney Hartz

    2016-01-01

    The presence of melanin in the fungal cell is a major virulence factor of the genus Sporothrix since it protects the fungal cells against the defense systems. The present study aimed to investigate the interference of melanin in the susceptibility of Sporothrix brasiliensis and Sporothrix schenckii sensu stricto to amphotericin B and itraconazole, drugs recommended as therapy for disseminated and subcutaneous sporotrichosis, respectively. Yeast cells were cultivated in minimal medium with or without l-DOPA in order to induce the production of melanin. Microdilution and killing assay methods were used to determine the antifungal activity against yeast cells with different amounts of melanin. The killing assay showed that melanization protected isolates within the S. schenckii complex from amphotericin B, particularly in the lower concentrations tested. Studies combining amphotericin B and inhibitors of melanin are required in order to avoid this effect. Copyright © 2014 Asociación Española de Micología. Published by Elsevier Espana. All rights reserved.

  14. Transferring biomarker into molecular probe: melanin nanoparticle as a naturally active platform for multimodality imaging.

    Science.gov (United States)

    Fan, Quli; Cheng, Kai; Hu, Xiang; Ma, Xiaowei; Zhang, Ruiping; Yang, Min; Lu, Xiaomei; Xing, Lei; Huang, Wei; Gambhir, Sanjiv Sam; Cheng, Zhen

    2014-10-29

    Developing multifunctional and easily prepared nanoplatforms with integrated different modalities is highly challenging for molecular imaging. Here, we report the successful transfer of an important molecular target, melanin, into a novel multimodality imaging nanoplatform. Melanin is abundantly expressed in melanotic melanomas and thus has been actively studied as a target for melanoma imaging. In our work, the multifunctional biopolymer nanoplatform based on ultrasmall (passive nanoplatforms require complicated and time-consuming processes for prebuilding reporting moieties or chemical modifications using active groups to integrate different contrast properties into one entity. In comparison, utilizing functional biomarker melanin can greatly simplify the building process. We further conjugated αvβ3 integrins, cyclic c(RGDfC) peptide, to MNPs to allow for U87MG tumor accumulation due to its targeting property combined with the enhanced permeability and retention (EPR) effect. The multimodal properties of MNPs demonstrate the high potential of endogenous materials with multifunctions as nanoplatforms for molecular theranostics and clinical translation.

  15. Quantitative photoacoustics to measure single cell melanin production and nanoparticle attachment

    Science.gov (United States)

    Bhattacharyya, Kiran; Eshein, Adam; Chandrasekhar, Anand; Viator, John A.

    2015-04-01

    Photoacoustics can be used as a label-free spectroscopic method of identifying pigmented proteins and characterizing their intracellular concentration over time in a single living cell. The authors use a microscopic laser irradiation system with a 5 ns, Q-switched laser focused onto single cells in order to collect photoacoustic responses of melanoma cells from the HS936 cell line and gold nanoparticle labeled breast cancer cells from the T47D cell line. The volume averaged intracellular concentration of melanin is found to range from 29-270 mM for single melanoma cells and the number of gold nanoparticles (AuNP) is shown to range from 850-5900 AuNPs/cell. Additionally, the melanin production response to UV-A light stimulus is measured in four melanoma cells to find a mass production rate of 5.7 pg of melanin every 15 min.

  16. Phenolic melanin precursors provide a rational approach to the design of antitumor agents for melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Jimbow, K.; Miura, T.; Ito, S.; Ishikawa, K.

    1989-01-01

    A unique biological property of the melanocyte, melanin synthesis may permit a rational approach to design agents for better management of malignant melanoma. This in vivo and in vitro study examined the selective melanocytotoxicity and antimelanoma effects of phenolic compounds, cysteinylphenol (CP), cysteaminylphenol (CAP), and related compounds, and found (1) that both 4-S-CP and 4-S-CAP are melanin precursors, (2) that 4-S-CAP possesses a marked depigmenting potency with selective destruction of melanocytes in black follicles, and (3) a significant inhibition in the protein synthesis and tumor growth of B16 melanoma. Importantly, a whole body autoradiography indicated that these phenolic melanin precursors are selectively incorporated into melanoma tissues after i.p. administration.

  17. Early diagnosis of melanotic melanoma based on laser-induced melanin fluorescence

    Science.gov (United States)

    Eichhorn, Reinhold; Wessler, Gerd; Scholz, Matthias; Leupold, Dieter; Stankovic, Goran; Buder, Susanne; Stücker, Markus; Hoffmann, Klaus

    2009-05-01

    Because of the increasing incidence of skin cancer, interest in using the autofluorescence of skin tissue as a noninvasive tool for early diagnosis is enforced. Focus is especially on malignant melanotic melanoma. On the basis of a newly developed method to selectively excite melanin fluorescence of skin tissue by stepwise two-photon excitation with nanosecond laser pulses at 810 nm, we have investigated information from this melanin fluorescence with respect to the differentiation of pigmented lesions. A distinct difference in the melanin fluorescence spectrum of malignant melanoma (including melanoma in situ) when compared to that of benign melanocytic lesions (i.e., common nevi) has been found for freshly excised samples as well as for histopathological samples. There is also specific fluorescence from dysplastic nevi. In this way, early detection of malignant melanoma is possible.

  18. Analysis of the melanin distribution in different ethnic groups by in vivo laser scanning microscopy

    Science.gov (United States)

    Antoniou, C.; Lademann, J.; Richter, H.; Astner, S.; Patzelt, A.; Zastrow, L.; Sterry, W.; Koch, S.

    2009-05-01

    The aim of this study was to determine whether Laser scanning confocal microscopy (LSM) is able to visualize differences in melanin content and distribution in different Skin Phototypes. The investigations were carried out on six healthy volunteers with Skin Phototypes II, IV, and VI. Representative skin samples of Skin Phototypes II, V, and VI were obtained for histological analysis from remaining tissue of skin grafts and were used for LSM-pathologic correlation. LSM evaluation showed significant differences in melanin distribution in Skin Phototypes II, IV, and VI, respectively. Based on the differences in overall reflectivity and image brightness, a visual evaluation scheme showed increasing brightness of the basal and suprabasal layers with increasing Skin Phototypes. The findings correlated well with histological analysis. The results demonstrate that LSM may serve as a promising adjunctive tool for real time assessment of melanin content and distribution in human skin, with numerous clinical applications and therapeutic and preventive implications.

  19. Melanin pigments in the melanocytic nevus regress spontaneously after inactivation by high hydrostatic pressure.

    Science.gov (United States)

    Sakamoto, Michiharu; Morimoto, Naoki; Jinno, Chizuru; Mahara, Atsushi; Ogino, Shuichi; Suzuki, Shigehiko; Kusumoto, Kenji; Yamaoka, Tetsuji

    2017-01-01

    We report a novel treatment for giant congenital melanocytic nevi (GCMN) that involves the reuse of resected nevus tissue after high hydrostatic pressurization (HHP). However, the remaining melanin pigments in the inactivated nevus tissue pose a problem; therefore, we performed a long-term observation of the color change of inactivated nevus tissue after HHP. Pressurized nevus specimens (200 MPa group, n = 9) and non-pressurized nevus tissues (control group, n = 9) were subcutaneously implanted into nude mice (BALB/c-nu) and then harvested 3, 6, and 12 months later. Color changes of the nevus specimens were evaluated. In the 200 MPa group, the specimen color gradually regressed and turned white, and brightness values were significantly higher in the 200 MPa group than in the control group after 6 months. This indicated that melanin pigments in the pressurized nevus tissue had spontaneously degraded and regressed. Therefore, it is not necessary to remove melanin pigments in HHP-treated nevus tissue.

  20. A Photoplethysmography Melanin Evaluation System by Modified Boltzmann Transport Equation (BTE

    Directory of Open Access Journals (Sweden)

    Sheng-Chieh Huang

    2015-01-01

    Full Text Available With the advance in cosmetic medical technology in recent years, more and more people get cosmetic medical treatments, especially skin whitening treatments. Nevertheless, people usually assess the effect of skin whitening products by vision, which is subjective and will be different from each person. To acquire the value of melanin concentration objectively, people need to go to cosmetic medical clinics. This will cause inconvenience to people. This paper develops a novel evaluation platform based on optical assessment methods, which employ different absorption and scattering properties to different wavelengths of light in human tissue to obtain melanin concentration. Moreover, this paper proposes a new method that compensates the interaction between epidermis and dermis to acquire the melanin concentration more accurately. The novel platform designed in this paper is smaller and consumes lower-power and smaller when comparing to other conventional devices in market.

  1. Pigment Melanin Scavenges Nitric Oxide In Vitro: Possible Relevance to Keloid Formation

    Directory of Open Access Journals (Sweden)

    Julian M. Menter

    2008-01-01

    Full Text Available Recently, nitric oxide (NO has been implicated in the formation of keloids, preferentially formed in dark-skinned persons, and we suspected that pigment melanin itself may play a direct role by adsorbing NO. We tested the ability of cuttlefish sepia melanin to scavenge (adsorb NO, generated in situ by 2-(N.N Diethylamino diazeneolate-2-oxide (DEA/NO, through a dialysis membrane. NO was measured as NO2_ and NO3_ by the Griess method and as N2O3 by trapping experiments with the fluorogenic substrate 4,5-diaminofluorescein (DAF-2. Initial NO2_ and NO3_ concentrations were significantly lower in the test dialyzates than in controls. Scavenging of NO was rapid enough to compete with DAF adduct formation. Both analytical methods gave comparable results. Adsorbed NO and/or its oxidized products may undergo interactions with melanin, adsorbed O2, and/or dermal material that may lead to keloid formation.

  2. Oral melanin pigmentation in 467 Thai and Malaysian people with special emphasis on smoker's melanosis.

    Science.gov (United States)

    Hedin, C A; Axéll, T

    1991-01-01

    At the faculties of dentistry in Chiang Mai, Thailand (CM), and Kuala Lumpur, Malaysia (KL), 234 and 233 consecutive out-patients were interviewed concerning tobacco and chewing habits and examined for the presence of oral melanin pigmentation. Tobacco was regularly used by 32% and 28% of the studied populations in CM and KL. Cigarette smoking was the predominant habit, but the chewing of betel and tea leaves (miang) and the smoking of banana leaf cigars (khi yo) was also registered. The genetically acquired pigmentation dominated. Although nearly all non-tobacco users in the Malay and Indian populations had oral melanin pigmentation, it was found that tobacco smokers had significantly more oral surfaces pigmented than non-tobacco users. Among Thais, the percentage of pigmented individuals was significantly higher among tobacco smokers. It was concluded that tobacco smoking stimulates oral melanocytes to a higher melanin production also in dark-skinned ethnic groups.

  3. Skip areas of retained melanin: A clue to the histopathological diagnosis of idiopathic guttate hypomelanosis

    Directory of Open Access Journals (Sweden)

    Rajiv Joshi

    2014-01-01

    Full Text Available Biopsy findings in 55 cases of idiopathic guttate hypomelanosis (IGH are reported. Most cases had a flat epidermis with loss of the rete pattern and a thickened orthokeratotic basket weave stratum corneum. The epidermis had markedly decreased to absent melanin in the basal layer and reduced numbers of melanocytes at the dermoepidermal junction. One-third of patients had a sparse perivascular lymphocytic infiltrate, whereas the rest had no significant dermal inflammation. These findings are in concordance with current literature.However, small foci of retained melanin in the basal layer (skip areas alternating with larger areas of melanin loss were present in almost 80% of cases. This finding has not been reported earlier and appears to be quite specific to IGH and may be used as a clue to differentiate IGH from other similar conditions such as vitiligo and guttate morphea.

  4. Melanin offers protection against induction of cyclobutane pyrimidine dimers and 6-4 photoproducts by UVB in cultured human melanocytes

    NARCIS (Netherlands)

    Smit, N.P.M.; Vink, A.A.; Kolb, R.M.; Steenwinkel, M.J.S.T.; Berg, P.T.M. van den; Nieuwpoort, F. van; Roza, L.; Pavel, S.

    2001-01-01

    The goal of this investigation was to correlate the melanin content in human pigmentary cells with the generation of UVB-induced photoproducts and to examine the relationship between the melanin content and the removal of the photoproducts. Cultured melanocytes from light-skinned individuals

  5. Flux pinning mechanism and H{sub c2}-anisotropy in melanin doped bulk MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Shahabuddin Shah, M., E-mail: mshahabuddin@ksu.edu.sa; Shahabuddin, Mohammed; Alzayed, Nasser S.; Parakkandy, Jafar M.

    2014-06-15

    Highlights: • Melanin doping enhances superconducting properties of MgB{sub 2}. • Grain boundary pinning is the dominant pinning mechanism in melanin doped MgB{sub 2}. • Experimental J{sub c} data could be very closely fitted using Percolation model. • Anisotropy is reduced due to melanin doping resulting in increase in J{sub c} in high field. • Pinning force maximum is suppressed due to melanin doping. - Abstract: Flux pinning mechanism in melanin doped MgB{sub 2} superconductor has been studied using a scaling law proposed by Dew-Hughes and another method proposed by Eisterer. Our experimental data could be fitted very closely by the aforementioned scaling law. The fitting parameters, the positions of peaks b{sub peak} and k = b{sub peak}/b{sub n} confirm a grain-boundary pinning in the 10% melanin doped sample, while the undoped sample consists of mixed pinning. Furthermore, percolation theory was utilized under grain-boundary approximation to investigate the role of H{sub c2}-anisotropy in the critical current density, and its dependence on applied field as well as temperature. The H{sub c2}-anisotropy decreases with melanin doping resulting in the increase of J{sub c} in high field. There is suppression of flux pinning maximum due to melanin doping, which is found to be the main reason for the degradation of low-field J{sub c}.

  6. Sexual Dichromatism of the Damselfly Calopteryx japonica Caused by a Melanin-Chitin Multilayer in the Male Wing Veins

    NARCIS (Netherlands)

    Stavenga, Doekele G.; Leertouwer, Hein L.; Hariyama, Takahiko; De Raedt, Hans A.; Wilts, Bodo D.

    2012-01-01

    Mature male Calopteryx japonica damselflies have dark-blue wings, due to darkly coloured wing membranes and blue reflecting veins. The membranes contain a high melanin concentration and the veins have a multilayer of melanin and chitin. Female and immature C. japonica damselflies have brown wings.

  7. Melanin deposition ruled out as cause of color changes in the red-eared sliders (Trachemys scripta elegans).

    Science.gov (United States)

    Cao, Dainan; Gong, Shiping; Yang, Jiangbo; Li, Weiye; Ge, Yan; Wei, Yufeng

    2018-03-01

    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. Moreover, the full-length coding sequence (CDS) of red-eared slider turtle melanin biosynthesis regulatory genes TYR, TYRP1, MITF and SLC24A5 were cloned, sequenced and quantitatively analyzed. Both histological view of melanin deposition and quantitative real-time PCR test of melanin-regulated gene expressions showed that there are significant differences among different tissues of red-eared slider, but no significant difference among different color-types, indicating that melanin deposition is not associated with ontogenetic color change in the carapace of red-eared slider. This study initially explore the melanin deposition and the mRNA expression of melanin biosynthesis regulatory genes in red-eared slider, which serve as a foundation for further insight into the pigmentation patterns and the mechanism of body color change in turtles. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. In vivo measurements of cutaneous melanin across spatial scales: using multiphoton microscopy and spatial frequency domain spectroscopy

    Science.gov (United States)

    Saager, Rolf B.; Balu, Mihaela; Crosignani, Viera; Sharif, Ata; Durkin, Anthony J.; Kelly, Kristen M.; Tromberg, Bruce J.

    2015-06-01

    The combined use of nonlinear optical microscopy and broadband reflectance techniques to assess melanin concentration and distribution thickness in vivo over the full range of Fitzpatrick skin types is presented. Twelve patients were measured using multiphoton microscopy (MPM) and spatial frequency domain spectroscopy (SFDS) on both dorsal forearm and volar arm, which are generally sun-exposed and non-sun-exposed areas, respectively. Both MPM and SFDS measured melanin volume fractions between ˜5% (skin type I non-sun-exposed) and 20% (skin type VI sun exposed). MPM measured epidermal (anatomical) thickness values ˜30-65 μm, while SFDS measured melanin distribution thickness based on diffuse optical path length. There was a strong correlation between melanin concentration and melanin distribution (epidermal) thickness measurements obtained using the two techniques. While SFDS does not have the ability to match the spatial resolution of MPM, this study demonstrates that melanin content as quantified using SFDS is linearly correlated with epidermal melanin as measured using MPM (R2=0.8895). SFDS melanin distribution thickness is correlated to MPM values (R2=0.8131). These techniques can be used individually and/or in combination to advance our understanding and guide therapies for pigmentation-related conditions as well as light-based treatments across a full range of skin types.

  9. Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration.

    Science.gov (United States)

    Roulin, Alexandre

    2016-05-01

    The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.

  10. A comparison of melanin bleaching and azure blue counterstaining in the immunohistochemical diagnosis of malignant melanoma.

    Science.gov (United States)

    Kligora, C J; Fair, K P; Clem, M S; Patterson, J W

    1999-12-01

    Distinguishing heavily pigmented melanocytes from melanophages on routine hematoxylin and eosin slides can be difficult. Melanin bleaching with potassium permanganate solution is a traditional means of removing melanin from tissues and can be used before immunohistochemical staining to remove any pigment that might be confused with the brown chromogen diaminobenzidine. Azure B stains melanin granules green-blue, easily contrasts with diaminobenzidine, and may be used as a counterstain on unbleached sections after immunohistochemical staining. To our knowledge, studies comparing melanin bleaching with azure B counterstaining in the immunohistochemical evaluation of malignant melanomas have not been performed. Paraffin sections from 33 heavily pigmented malignant melanomas were bleached with a 3.0-g/L potassium permanganate solution, immunohistochemically stained for S-100 and HMB-45, and counterstained with hematoxylin. Unbleached sections were similarly stained for S-100 and HMB-45 and counterstained with azure B. To establish optimal permanganate concentrations, a variable number of sections were bleached with lower permanganate concentrations ranging from 0.125 to 2.5 g/L. S-100 antigenicity was preserved at all permanganate concentrations, whereas HMB-45 antigenicity was abolished at concentrations of 0.5 g/L and greater. At permanganate concentrations from 0.125 to 0.5 g/L, both antigenicities were preserved; however, melanin was incompletely removed. Complications of bleaching included tissue damage and loss of cytologic detail. Positive immunohistochemical staining was observed in azure B counterstained sections. Azure B stained melanin greenblue and was easily distinguished from the brown diaminobenzidine chromogen, regardless of the antibody tested. Neither tissue damage nor loss of cytologic detail was observed. We conclude that the use of azure B counterstaining is superior to permanganate bleaching in the histologic evaluation of heavily pigmented

  11. A novel S-sulfhydrated human serum albumin preparation suppresses melanin synthesis

    Directory of Open Access Journals (Sweden)

    Mayumi Ikeda

    2018-04-01

    Full Text Available Products of ultraviolet (UV irradiation such as reactive oxygen species (ROS and nitric oxide (NO stimulate melanin synthesis. Reactive sulfur species (RSS have been shown to have strong ROS and NO scavenging effects. However, the instability and low retention of RSS limit their use as inhibitors of melanin synthesis. The free thiol at Cys34 on human serum albumin (HSA is highly stable, has a long retention and possess a high reactivity for RSS. We report herein on the development of an HSA based RSS delivery system. Sulfane sulfur derivatives released from sodium polysulfides (Na2Sn react readily with HSA. An assay for estimating the elimination of sulfide from polysulfide showed that almost all of the sulfur released from Na2Sn bound to HSA. The Na2Sn-treated HSA was found to efficiently scavenge ROS and NO produced from chemical reagents. The Na2Sn-treated HSA was also found to inhibit melanin synthesis in B16 melanoma cells and this inhibition was independent of the number of added sulfur atoms. In B16 melanoma cells, the Na2Sn-treated HSA also inhibited the levels of ROS and NO induced by UV radiation. Finally, the Na2Sn-treated HSA inhibited melanin synthesis from L-DOPA and mushroom tyrosinase and suppressed the extent of aggregation of melanin pigments. These data suggest that Na2Sn-treated HSA inhibits tyrosinase activity for melanin synthesis via two pathways; by directly inhibiting ROS signaling and by scavenging NO. These findings indicate that Na2Sn-treated HSA has potential to be an attractive and effective candidate for use as a skin whitening agent. Keywords: Ultraviolet irradiation, Human serum albumin, Reactive sulfur species, Whitening agent, Oxidative stress

  12. A novel S-sulfhydrated human serum albumin preparation suppresses melanin synthesis.

    Science.gov (United States)

    Ikeda, Mayumi; Ishima, Yu; Kinoshita, Ryo; Chuang, Victor T G; Tasaka, Nanami; Matsuo, Nana; Watanabe, Hiroshi; Shimizu, Taro; Ishida, Tatsuhiro; Otagiri, Masaki; Maruyama, Toru

    2018-04-01

    Products of ultraviolet (UV) irradiation such as reactive oxygen species (ROS) and nitric oxide (NO) stimulate melanin synthesis. Reactive sulfur species (RSS) have been shown to have strong ROS and NO scavenging effects. However, the instability and low retention of RSS limit their use as inhibitors of melanin synthesis. The free thiol at Cys34 on human serum albumin (HSA) is highly stable, has a long retention and possess a high reactivity for RSS. We report herein on the development of an HSA based RSS delivery system. Sulfane sulfur derivatives released from sodium polysulfides (Na 2 S n ) react readily with HSA. An assay for estimating the elimination of sulfide from polysulfide showed that almost all of the sulfur released from Na 2 S n bound to HSA. The Na 2 S n -treated HSA was found to efficiently scavenge ROS and NO produced from chemical reagents. The Na 2 S n -treated HSA was also found to inhibit melanin synthesis in B16 melanoma cells and this inhibition was independent of the number of added sulfur atoms. In B16 melanoma cells, the Na 2 S n -treated HSA also inhibited the levels of ROS and NO induced by UV radiation. Finally, the Na 2 S n -treated HSA inhibited melanin synthesis from L-DOPA and mushroom tyrosinase and suppressed the extent of aggregation of melanin pigments. These data suggest that Na 2 S n -treated HSA inhibits tyrosinase activity for melanin synthesis via two pathways; by directly inhibiting ROS signaling and by scavenging NO. These findings indicate that Na 2 S n -treated HSA has potential to be an attractive and effective candidate for use as a skin whitening agent. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Structural Color Tuning: Mixing Melanin-Like Particles with Different Diameters to Create Neutral Colors.

    Science.gov (United States)

    Kawamura, Ayaka; Kohri, Michinari; Yoshioka, Shinya; Taniguchi, Tatsuo; Kishikawa, Keiki

    2017-04-18

    We present the ability to tune structural colors by mixing colloidal particles. To produce high-visibility structural colors, melanin-like core-shell particles composed of a polystyrene (PSt) core and a polydopamine (PDA) shell, were used as components. The results indicated that neutral structural colors could be successfully obtained by simply mixing two differently sized melanin-like PSt@PDA core-shell particles. In addition, the arrangements of the particles, which were important factors when forming structural colors, were investigated by mathematical processing using a 2D Fourier transform technique and Voronoi diagrams. These findings provide new insights for the development of structural color-based ink applications.

  14. Photon absorption in step-wise multi-photon activation fluorescence (SMPAF) of Sepia melanin

    Science.gov (United States)

    Lai, Zhenhua; Kerimo, Josef; DiMarzio, Charles

    2013-02-01

    Previous research has shown that melanin goes through a step-wise three-photon absorption process when the fluorescence is activated with high laser intensity. We have conducted further research using even higher laser intensity for the activation, and have shown the possibility of observing power dependence other than third-order. This article discusses the possible energy states of Sepia melanin by studying the power dependence curves of the step-wise multi-photon activated fluorescence signal. Three different excitation channels are activated. Possible reasons causing the three channels are discussed.

  15. On the origin of electrical conductivity in the bio-electronic material melanin

    Science.gov (United States)

    Bernardus Mostert, A.; Powell, Ben J.; Gentle, Ian R.; Meredith, Paul

    2012-02-01

    The skin pigment melanin is one of a few bio-macromolecules that display electrical and photo-conductivity in the solid-state. A model for melanin charge transport based on amorphous semiconductivity has been widely accepted for 40 years. In this letter, we show that a central pillar in support of this hypothesis, namely experimental agreement with a hydrated dielectric model, is an artefact related to measurement geometry and non-equilibrium behaviour. Our results cast significant doubt on the validity of the amorphous semiconductor model and are a reminder of the difficulties of electrical measurements on low conductivity, disordered organic materials.

  16. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with multimodal photoacoustic ophthalmoscopy

    Science.gov (United States)

    Zhang, Xiangyang; Zhang, Hao F.; Zhou, Lixiang; Jiao, Shuliang

    2012-02-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective vs. exacerbate) in the RPE in the aging process. We successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  17. Prevention of melanin formation during aryl alcohol oxidase production under growth-limited conditions using an Aspergillus nidulans cell factory.

    Science.gov (United States)

    Pardo-Planas, Oscar; Prade, Rolf A; Müller, Michael; Atiyeh, Hasan K; Wilkins, Mark R

    2017-11-01

    An Aspergillus nidulans cell factory was genetically engineered to produce an aryl alcohol oxidase (AAO). The cell factory initiated production of melanin when growth-limited conditions were established using stationary plates and shaken flasks. This phenomenon was more pronounced when the strain was cultured in a trickle bed reactor (TBR). This study investigated different approaches to reduce melanin formation in fungal mycelia and liquid medium in order to increase the enzyme production yield. Removal of copper from the medium recipe reduced melanin formation in agar cultures and increased enzyme activities by 48% in agitated liquid cultures. Copper has been reported as a key element for tyrosinase, an enzyme responsible for melanin production. Ascorbic acid (0.44g/L) stopped melanin accumulation, did not affect growth parameters and resulted in AAO activity that was more than two-fold greater than a control treatment with no ascorbic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Sexual dichromatism of the damselfly Calopteryx japonica caused by a melanin-chitin multilayer in the male wing veins.

    Directory of Open Access Journals (Sweden)

    Doekele G Stavenga

    Full Text Available Mature male Calopteryx japonica damselflies have dark-blue wings, due to darkly coloured wing membranes and blue reflecting veins. The membranes contain a high melanin concentration and the veins have a multilayer of melanin and chitin. Female and immature C. japonica damselflies have brown wings. We have determined the refractive index of melanin by comparing the differently pigmented wing membranes and applying Jamin-Lebedeff interference microscopy. Together with the previously measured refractive index of chitin the blue, structural colour of the male wing veins could be quantitatively explained by an optical multilayer model. The obtained melanin refractive index data will be useful in optical studies on melanized tissues, especially where melanin is concentrated in layers, thus causing iridescence.

  19. Autophagy participates in isoliquiritigenin-induced melanin degradation in human epidermal keratinocytes through PI3K/AKT/mTOR signaling.

    Science.gov (United States)

    Yang, Zhibo; Zeng, Biyun; Pan, Yi; Huang, Pan; Wang, Chang

    2018-01-01

    Melanin is the pigment responsible for the color of human skin and hair. Melanin serves as a double-edge sword which can exert both protective and spot-causing effects on skin. Although melanin has an important role in protecting the skin against UV damage, an excessive or uneven melanin production can lead to the formation of freckles and age spots. Isoliquiritigenin (ISL) has been reported to inhibit melanin synthesis; however, its role in melanin degradation remains unclear. In the present study, we evaluated the detailed function of ISL in melanin degradation in human epidermal keratinocytes. Since autophagy has been reported to be related to melanin degradation, we also examined the activation of autophagy by ISL treatment in keratinocytes by measurement of autophagy-related proteins, ATG7, LC3 and p62. Moreover, si-ATG7-induced ATG7 knockdown and autophagy inhibitor 3-MA decreased LC3 II protein levels and increased PMEL17, p62 and melanin levels in HaCaT cells, which could be partially reversed by ISL treatment, indicating that autophagy participated in melanin degradation. The decreased p-AKT and p-mTOR proteins upon ISL treatment indicated the involvement of PI3K/AKT/mTOR signaling in ISL-induced melanin degradation. Taken together, we demonstrated that autophagy participates in ISL-induced melanin degradation in human epidermal keratinocytes through PI3K/AKT/mTOR signaling. Copyright © 2017. Published by Elsevier Masson SAS.

  20. Protection of melanized Cryptococcus neoformans from lethal dose gamma irradiation involves changes in melanin's chemical structure and paramagnetism.

    Directory of Open Access Journals (Sweden)

    Abdelahad Khajo

    Full Text Available Certain fungi thrive in highly radioactive environments including the defunct Chernobyl nuclear reactor. Cryptococcus neoformans (C. neoformans, which uses L-3,4-dihydroxyphenylalanine (L-DOPA to produce melanin, was used here to investigate how gamma radiation under aqueous aerobic conditions affects the properties of melanin, with the aim of gaining insight into its radioprotective role. Exposure of melanized fungal cell in aqueous suspensions to doses of γ-radiation capable of killing 50 to 80% of the cells did not lead to a detectable loss of melanin integrity according to EPR spectra of melanin radicals. Moreover, upon UV-visible (Xe-lamp illumination of melanized cells, the increase in radical population was unchanged after γ-irradiation. Gamma-irradiation of frozen cell suspensions and storage of samples for several days at 77 K however, produced melanin modification noted by a reduced radical population and reduced photoresponse. More direct evidence for structural modification of melanin came from the detection of soluble products with absorbance maxima near 260 nm in supernatants collected after γ-irradiation of cells and cell-free melanin. These products, which include thiobarbituric acid (TBA-reactive aldehydes, were also generated by Fenton reagent treatment of cells and cell-free melanin. In an assay of melanin integrity based on the metal (Bi(+3 binding capacity of cells, no detectable loss in binding was detected after γ-irradiation. Our results show that melanin in C. neoformans cells is susceptible to some damage by hydroxyl radical formed in lethal radioactive aqueous environments and serves a protective role in melanized fungi that involves sacrificial breakdown.

  1. Dual-wavelength pump-probe microscopy analysis of melanin composition

    Science.gov (United States)

    Thompson, Andrew; Robles, Francisco E.; Wilson, Jesse W.; Deb, Sanghamitra; Calderbank, Robert; Warren, Warren S.

    2016-01-01

    Pump-probe microscopy is an emerging technique that provides detailed chemical information of absorbers with sub-micrometer spatial resolution. Recent work has shown that the pump-probe signals from melanin in human skin cancers correlate well with clinical concern, but it has been difficult to infer the molecular origins of these differences. Here we develop a mathematical framework to describe the pump-probe dynamics of melanin in human pigmented tissue samples, which treats the ensemble of individual chromophores that make up melanin as Gaussian absorbers with bandwidth related via Frenkel excitons. Thus, observed signals result from an interplay between the spectral bandwidths of the individual underlying chromophores and spectral proximity of the pump and probe wavelengths. The model is tested using a dual-wavelength pump-probe approach and a novel signal processing method based on gnomonic projections. Results show signals can be described by a single linear transition path with different rates of progress for different individual pump-probe wavelength pairs. Moreover, the combined dual-wavelength data shows a nonlinear transition that supports our mathematical framework and the excitonic model to describe the optical properties of melanin. The novel gnomonic projection analysis can also be an attractive generic tool for analyzing mixing paths in biomolecular and analytical chemistry. PMID:27833147

  2. Melanin precursors prevent premature age-related and noise-induced hearing loss in albino mice.

    Science.gov (United States)

    Murillo-Cuesta, Silvia; Contreras, Julio; Zurita, Esther; Cediel, Rafael; Cantero, Marta; Varela-Nieto, Isabel; Montoliu, Lluís

    2010-02-01

    Strial melanocytes are required for normal development and correct functioning of the cochlea. Hearing deficits have been reported in albino individuals from different species, although melanin appears to be not essential for normal auditory function. We have analyzed the auditory brainstem responses (ABR) of two transgenic mice: YRT2, carrying the entire mouse tyrosinase (Tyr) gene expression-domain and undistinguishable from wild-type pigmented animals; and TyrTH, non-pigmented but ectopically expressing tyrosine hydroxylase (Th) in melanocytes, which generate the precursor metabolite, L-DOPA, but not melanin. We show that young albino mice present a higher prevalence of profound sensorineural deafness and a poorer recovery of auditory thresholds after noise-exposure than transgenic mice. Hearing loss was associated with absence of cochlear melanin or its precursor metabolites and latencies of the central auditory pathway were unaltered. In summary, albino mice show impaired hearing responses during ageing and after noise damage when compared to YRT2 and TyrTH transgenic mice, which do not show the albino-associated ABR alterations. These results demonstrate that melanin precursors, such as L-DOPA, have a protective role in the mammalian cochlea in age-related and noise-induced hearing loss.

  3. RESEARCH ARTICLE Map the locus of Id for dermal shank melanin ...

    Indian Academy of Sciences (India)

    Navya

    2017-03-24

    Mar 24, 2017 ... Map the locus of Id for dermal shank melanin in a Chinese indigenous chicken breed. JIGUO XU1,2,#, SHUDAI LIN1,2,#, XINFENG GAO1,2,QINGHUA NIE1,2, QINBIN. LUO1,2, XIQUAN ZHANG1,2*. 1College of Animal Science, South China Agricultural University Guangzhou,. Guangdong, China.

  4. Positive Relationship between Abdominal Coloration and Dermal Melanin Density in Phrynosomatid Lizards

    Science.gov (United States)

    Vanessa S. Quinn; Diana K. Hews

    2003-01-01

    Phrynosomatid lizards show considerable variation among species in the occurrence of a secondary sexual trait, blue abdominal coloration. The production of blue skin may be controlled by at least two cellular components, melanin in melanophores, and guanine in iridophores. To examine the hypothesis that a mechanism producing variation in abdominal coloration is...

  5. Mapping of Id locus for dermal shank melanin in a Chinese ...

    Indian Academy of Sciences (India)

    JIGUO XU

    2017-12-08

    Dec 8, 2017 ... Introduction. The phenotypic diversity of pigmentation in wild animals and domesticated animals is one of the most observed char- acteristics by biologists and breeders. The phenotype of the shank skin colour is a defining trait of the breeds of chick- ens, and it is due to the interaction between the melanins.

  6. Melanin-related metabolites as markers of the skin pigmentary system

    NARCIS (Netherlands)

    Westerhof, W.; Pavel, S.; Kammeyer, A.; Beusenberg, F. D.; Cormane, R.

    1987-01-01

    Three different groups of chemical intermediates are known to be formed during the synthesis of melanin in melanocytes: phenolic compounds, phenolic thio-conjugates, and indolic compounds. All these substances and their metabolites can be detected in urine. We measured the urinary excretion of

  7. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Directory of Open Access Journals (Sweden)

    Hwayong Park

    2013-01-01

    Full Text Available To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content.

  8. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Science.gov (United States)

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content. PMID:23781272

  9. Combined effects of Cu and UVR on survival and melanin synthesis in Chironomus riparius larvae

    NARCIS (Netherlands)

    de Baat, M.L.; van Gemert, M.; Verweij, R.A.; Loayza Muro, R.A.; Kraak, M.H.S.

    2012-01-01

    The tropical Andes encompass vast areas with altitudes above 4000 m, where the combination of high UV radiation and metal pollution creates environments that challenge the survival and persistence of aquatic life. Since the pigment melanin counteracts the negative effects of UVR, and has the

  10. Increased melanin concentrating hormone receptor type I in the human hypothalamic infundibular nucleus in cachexia

    NARCIS (Netherlands)

    Unmehopa, Unga A.; van Heerikhuize, Joop J.; Spijkstra, Wenda; Woods, John W.; Howard, Andrew D.; Zycband, Emanuel; Feighner, Scott D.; Hreniuk, Donna L.; Palyha, Oksana C.; Guan, Xiao-Ming; Macneil, Douglas J.; van der Ploeg, Lex H. T.; Swaab, Dick F.

    2005-01-01

    Melanin-concentrating hormone (MCH) exerts a positive regulation on appetite and binds to the G protein-coupled receptors, MCH1R and MCH2R. In rodents, MCH is produced by neurons in the lateral hypothalamus with projections to various hypothalamic and other brain sites. In the present study, MCH1R

  11. Mapping of Id locus for dermal shank melanin in a Chinese ...

    Indian Academy of Sciences (India)

    JIGUO XU

    2017-12-08

    Dec 8, 2017 ... of 96 Gushi hens and 96 Gushi hens with a yellow shank skin colour. The results of the ... Gushi chicken; sex-linked inhibitor of dermal melanin; GRAMD3 gene; shank skin colour. Introduction. The phenotypic diversity of ..... ventral pathway, which is normally reserved for cells of neuronal and glial lineages, ...

  12. Technological Desition of Extraction of Melanin from the Waste of Production of Sunflower-Seed Oil

    Science.gov (United States)

    Kartushina, Yu N.; Nefedieva, E. E.; Sevriukova, G. A.; Gracheva, N. V.; Zheltobryukhov, V. F.

    2017-05-01

    The research was realized in the field of the technology for re-use of waste of sunflower-seed oil production. A technological scheme of production of melanin from sunflower husk as a waste was developed. Re-cycling will give the opportunity to reduce the amount of waste and to obtain an additional source of income.

  13. Melanin-independent accumulation of turgor pressure in appressoria of Phakopsora pachyrhizi

    Science.gov (United States)

    In some plant pathogenic fungi, turgor pressure accumulation in appressoria produces a mechanical force enabling the direct penetration of hyphae through the plant cell epidermis. Melanin has been reported to function as an impermeable barrier to osmolytes, which allow appressoria to accumulate high...

  14. Melanin Bleaching With Warm Hydrogen Peroxide and Integrated Immunohistochemical Analysis: An Automated Platform.

    Science.gov (United States)

    Liu, Chia-Hsing; Lin, Chih-Hung; Tsai, Min-Jan; Chen, Yu-Hsuan; Yang, Sheau-Fang; Tsai, Kun-Bow

    2018-02-01

    Diagnosing melanocytic lesions is among the most challenging problems in the practice of pathology. The difficulty of physically masking melanin pigment and the similarity of its color to commonly used chromogens often complicate examination of the cytomorphology and immunohistochemical staining results for tumor cells. Melanin bleach can be very helpful for histopathological diagnosis of heavily pigmented melanocytic lesions. Although various depigmentation methods have been reported, no standardized methods have been developed. This study developed a fully automated platform that incorporates hydrogen peroxide-based melanin depigmentation in an automated immunohistochemical analysis. The utility of the method was tested in 1 cell block of malignant melanoma cells in pleural effusion, 10 ocular melanoma tissue samples, and 10 cutaneous melanoma tissue samples. Our results demonstrated that the proposed method, which can be performed in only 3 hours, effectively preserves cell cytomorphology and immunoreactivity. The method is particularly effective for removing melanin pigment to facilitate histopathological examination of cytomorphology and for obtaining an unmasked tissue section for immunohistochemical analysis.

  15. Neural Stem Cells and Its Derivatives as a New Material for Melanin Inhibition.

    Science.gov (United States)

    Hwang, Insik; Hong, Sunghoi

    2017-12-22

    The pigment molecule, melanin, is produced from melanosomes of melanocytes through melanogenesis, which is a complex process involving a combination of chemical and enzymatically catalyzed reactions. The synthesis of melanin is primarily influenced by tyrosinase (TYR), which has attracted interest as a target molecule for the regulation of pigmentation or depigmentation in skin. Thus, direct inhibitors of TYR activity have been sought from various natural and synthetic materials. However, due to issues with these inhibitors, such as weak or permanent ability for depigmentation, allergy, irritant dermatitis and rapid oxidation, in vitro and in vivo, the development of new materials that inhibit melanin production is essential. A conditioned medium (CM) derived from stem cells contains many cell-secreted factors, such as cytokines, chemokines, growth factors and extracellular vesicles including exosomes. In addition, the secreted factors could negatively regulate melanin production through stimulation of a microenvironment of skin tissue in a paracrine manner, which allows the neural stem cell CM to be explored as a new material for skin depigmentation. In this review, we will summarize the current knowledge regulating depigmentation, and discuss the potential of neural stem cells and their derivatives, as a new material for skin depigmentation.

  16. Melanin-based color of plumage: role of condition and of feathers' microstructure

    Science.gov (United States)

    D'Alba, Liliana; Van Hemert, Caroline R.; Spencer, Karen A.; Heidinger, Britt J.; Gill, Lisa; Evans, Neil P.; Monaghan, Pat; Handel, Colleen M.; Shawkey, Matthew D.

    2014-01-01

    Whether melanin-based colors honestly signal a bird's condition during the growth of feathers is controversial, and it is unclear if or how the physiological processes underlying melanogenesis or color-imparting structural feather microstructure may be adversely affected by condition. Here we report results from two experiments designed to measure the effect of condition on expression of eumelanic and pheomelanic coloration in black-capped chickadees (Poecile atricapillus) and zebra finches (Taeniopygia guttata), respectively. In chickadees, we compared feathers of birds affected and unaffected by avian keratin disorder, while in zebra finches we compared feathers of controls with feathers of those subjected to an unpredictable food supply during development. In both cases we found that control birds had brighter feathers (higher total reflectance) and more barbules, but similar densities of melanosomes. In addition, the microstructure of the feathers explained variation in color more strongly than did melanosome density. Together, these results suggest that melanin-based coloration may in part be condition-dependent, but that this may be driven by changes in keratin and feather development, rather than melanogenesis itself. Researchers should be cautious when assigning variation in melanin-based color to melanin alone and microstructure of the feather should be taken into account.

  17. Hypocretin and melanin-concentrating hormone in patients with Huntington disease.

    NARCIS (Netherlands)

    Aziz, A.; Fronczek, R.; Maat-Schieman, M.L.; Unmehopa, U.A.; Roelandse, F.W.; Overeem, S.; Duinen, S.G. van; Lammers, G.J.; Swaab, D.F.; Roos, R.A.C.

    2008-01-01

    To evaluate whether hypocretin-1 (orexin-A) and melanin-concentrating hormone (MCH) neurotransmission are affected in patients with Huntington disease (HD), we immunohistochemically stained hypocretin and MCH neurons and estimated their total numbers in the lateral hypothalamus of both HD patients

  18. High refractive index of melanin in shiny occipital feathers of a bird of paradise

    NARCIS (Netherlands)

    Stavenga, Doekele G.; Leertouwer, Heinrich; Osorio, Daniel C.; Wilts, Bodo D.

    Male Lawes's Parotia, a bird of paradise, use the highly directional reflection of the structurally colored, brilliant-silvery occipital feathers in their courtship display. As in other birds, the structural coloration is produced by ordered melanin pigmentation. The barbules of the Parotia's

  19. Differential effects of endoparasitism on the expression of carotenoid- and melanin-based ornamental coloration.

    Science.gov (United States)

    McGraw, K J; Hill, G E

    2000-01-01

    The striking diversity of sexual dimorphisms in nature begs the question: Why are there so many signal types? One possibility is that ornamental traits convey different sets of information about the quality of the sender to the receiver. The colourful, pigmented feathers of male birds seem to meet the predictions of this hypothesis. Evidence suggests that carotenoid pigmentation reflects the nutritional condition of males during moult, whereas in many instances melanin pigmentation is a reliable indicator of social status. However, as of yet there have been no experimental tests to determine how these two ornament types respond to the same form of environmental stress. In this study, we tested the effect of endoparasitic infection by intestinal coccidians (Isospora sp.) on the expression of both carotenoid- and melanin-based ornamental coloration in captive male American goldfinches (Carduelis tristis). We found that the carotenoid-based plumage and bill coloration of parasitized males was less saturated than that developed by unparasitized males, but that the brightness and size of melanin-based black caps did not differ between the groups. These findings provide the most robust empirical support to date for the notion that carotenoid and melanin ornaments reveal different information to conspecifics. PMID:11007328

  20. Silver nanoparticles mediated altered gene expression of melanin biosynthesis genes in Bipolaris sorokiniana.

    Science.gov (United States)

    Mishra, Sandhya; Singh, H B

    2015-03-01

    Melanin production in many fungal phytopathogens has been investigated to play direct or indirect role in pathogenesis. However, in Bipolaris sorokiniana, the spot blotch pathogen of wheat, much less is known about the role melanin play in pathogenesis. As an extension of our previous report, the present study aims to investigate the plausible association between melanin production and virulence factor in B. sorokiniana. In the previous study, we carried out analysis on the antifungal efficacy of biosynthesized silver nanoparticles (AgNPs) against B. sorokiniana. The present investigation revealed the gene expression analysis of melanin biosynthesis genes viz. polyketide synthase (PKS1) and scytalone dehydratase (SCD1) under the influence of AgNPs. The 0.05mg/ml concentration of AgNPs yielded noticeable inhibition of B. sorokiniana growth, while 0.1mg/ml concentration of AgNPs accounted for complete inhibition of pathogen growth. In addition, the semiquantitative RT-PCR analysis exhibited reduced expression of PKS1 and SCD1 under the influence of AgNPs treatment. Furthermore, the qRT-PCR demonstrated 6.47 and 1.808 fold significant decrease in the expression pattern of PKS1 and SCD1, respectively, in B. sorokiniana treated with AgNPs. The present study provides probable understanding of molecular events underlying the antifungal role of AgNPs against B. sorokiniana. Copyright © 2015 Elsevier GmbH. All rights reserved.

  1. GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C.; Ekechukwu, A.; Milliken, C.

    2011-05-17

    The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

  2. An alternative method for the analysis of melanin production in Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato.

    Science.gov (United States)

    Brilhante, Raimunda S N; España, Jaime D A; de Alencar, Lucas P; Pereira, Vandbergue S; Castelo-Branco, Débora de S C M; Pereira-Neto, Waldemiro de A; Cordeiro, Rossana de A; Sidrim, José J C; Rocha, Marcos F G

    2017-10-01

    Melanin is an important virulence factor for several microorganisms, including Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato, thus, the assessment of melanin production and its quantification may contribute to the understanding of microbial pathogenesis. The objective of this study was to standardise an alternative method for the production and indirect quantification of melanin in C. neoformans sensu lato and C. gattii sensu lato. Eight C. neoformans sensu lato and three C. gattii sensu lato, identified through URA5 methodology, Candida parapsilosis ATCC 22019 (negative control) and one Hortaea werneckii (positive control) were inoculated on minimal medium agar with or without L-DOPA, in duplicate, and incubated at 35°C, for 7 days. Pictures were taken from the third to the seventh day, under standardised conditions in a photographic chamber. Then, photographs were analysed using grayscale images. All Cryptococcus spp. strains produced melanin after growth on minimal medium agar containing L-DOPA. C. parapsilosis ATCC 22019 did not produce melanin on medium containing L-DOPA, while H. werneckii presented the strongest pigmentation. This new method allows the indirect analysis of melanin production through pixel quantification in grayscale images, enabling the study of substances that can modulate melanin production. © 2017 Blackwell Verlag GmbH.

  3. Generation and suppression of singlet oxygen in hair by photosensitization of melanin.

    Science.gov (United States)

    Chiarelli-Neto, Orlando; Pavani, Christiane; Ferreira, Alan S; Uchoa, Adjaci F; Severino, Divinomar; Baptista, Maurício S

    2011-09-15

    We have studied the spectroscopic properties of hair (white, blond, red, brown, and black) under illumination with visible light, giving special emphasis to the photoinduced generation of singlet oxygen ((1)O(2)). Irradiation of hair shafts (λ(ex)>400 nm) changed their properties by degrading the melanin. Formation of C3 hydroperoxides in the melanin indol groups was proven by (1)H NMR. After 532-nm excitation, all hair shafts presented the characteristic (1)O(2) emission (λ(em)=1270 nm), whose intensity varied inversely with the melanin content. (1)O(2) lifetime was also shown to vary with hair type, being five times shorter in black hair than in blond hair, indicating the role of melanin as a (1)O(2) suppressor. Lifetime ranged from tenths of a nanosecond to a few microseconds, which is much shorter than the lifetime expected for (1)O(2) in the solvents in which the hair shafts were suspended, indicating that (1)O(2) is generated and suppressed inside the hair structure. Both eumelanin and pheomelanin were shown to produce and to suppress (1)O(2), with similar efficiencies. The higher amount of (1)O(2) generated in blond hair and its longer lifetime is compatible with the stronger damage that light exposure causes in blond hair. We propose a model to explain the formation and suppression of (1)O(2) in hair by photosensitization of melanin with visible light and the deleterious effects that an excess of visible light may cause in hair and skin. Copyright © 2011. Published by Elsevier Inc.

  4. Inhibitory effect of Cinnamomum osmophloeum Kanehira ethanol extracts on melanin synthesis via repression of tyrosinase expression.

    Science.gov (United States)

    Lee, Shih-Chieh; Chen, Chun-Hao; Yu, Chih-Wen; Chen, Hsiao Ling; Huang, Wei-Tung; Chang, Yun-Shiang; Hung, Shu-Hsien; Lee, Tai-Lin

    2016-09-01

    Melanin contributes to skin color, and tyrosinase is the enzyme that catalyzes the initial steps of melanin formation. Therefore, tyrosinase inhibitors may contribute to the control of skin hyperpigmentation. The inhibition of tyrosinase activity by Cinnamomum zeylanicum extracts was previously reported. In this report, we test the hypothesis that Cinnamomum osmophloeum Kanehira, an endemic plant to Taiwan, contains compounds that inhibit tyrosinase activity, similar to C. zeylanicum. The cytotoxicity of three sources of C. osmophloeum Kanehira ethanol extracts was measured in B16-F10 cells using a methyl thiazolyl tetrazolium bromide (MTT) assay. At concentrations greater than 21.25 μg/mL, the ethanol extracts were toxic to the cells; therefore, 21.25 μg/mL was selected to test the tyrosinase activities. At this concentration, all three ethanol extracts decreased the melanin content by 50% in IBMX-induced B16-F10 cells. In addition to the melanin content, greater than 20% of the tyrosinase activity was inhibited by these ethanol extracts. The RT-PCR results showed that tyrosinase and transcription factor MITF mRNAs expression were down-regulated. Consistent with the mRNA results, greater than 40% of the human tyrosinase promoter activity was inhibited based on the reporter assay. Furthermore, our results demonstrate that the ethanol extracts protect cells from UV exposure. C. osmophloeum Kanehira neutralized the IBMX-induced increase in melanin content in B16-F10 cells by inhibiting tyrosinase gene expression at the level of transcription. Moreover, the ethanol extracts also partially inhibited UV-induced cell damage and prevented cell death. Taken together, we conclude that C. osmophloeum Kanehira is a potential skin-whitening and protective agent. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Melanin-targeted nonlinear microscopy for label-free molecular diagnosis and staining (Conference Presentation)

    Science.gov (United States)

    Warren, Warren S.

    2017-02-01

    Visible absorption in tissue is dominated by a very small number of chromophores (hemoglobins and melanins) with broad optical spectra; for melanins in particular, the optical absorption spectrum is typically featureless. In addition, scattering limits penetration depth. As a result, the most common microscopy application by far is with excised tissue, which can be stained. However, nonlinear optical methods have the additional advantages of greater penetration depth and reduced sensitivity to scattering. Traditional nonlinear microscopy relies on mechanisms which produce light of a different color than the irradiating lasers, such as second harmonic generation or two photon induced fluorescence, and this contrast is sparse in biological issue without expressing or injecting different chromophores. Recently, stable laser sources and pulse shaping/pulse train modulation methods have made it possible to detect a much wider range of nonlinear molecular signatures, even at modest laser powers (much less than a laser pointer). Here we show the utility of a variety of such signatures (pump-probe, pulse-shaped stimulated Raman, cross-phase modulation) to quantitatively image the biochemical composition of transparent or pigmented tissue in a variety of applications, ranging from thin, unstained tissue sections to live knockout mice. The rich biochemical information provided by this method can be used as an indicator of melanocyte activity, which in turn (for example) reflects the status of melanocytic lesions. Comparisons with model systems (synthetic melanin nanoparticles, sepia melanin) and analysis of melanin degradation pathways in vivo have led to a quantitative understanding of the molecular basis of these changes.

  6. Lactoferrin-melanin interaction and its possible implications in melanin polymerization: crystal structure of the complex formed between mare lactoferrin and melanin monomers at 2.7-A resolution.

    Science.gov (United States)

    Sharma, A K; Kumar, S; Sharma, V; Nagpal, A; Singh, N; Tamboli, I; Mani, I; Raman, G; Singh, T P

    2001-11-15

    The concentration of melanin determines the intensity of colors of the skin and hair of animals. Melanin pigments are tyrosine-based polymers formed in melanocytes within specialized organelles called melanosomes. In order to understand the mechanism of melanin polymerization, lactoferrin, a basic protein with a pI value of 9.0, has been used to produce melanin. Lactoferrin is a monomeric iron-binding protein with a molecular weight of 80 kDa. The crystals of lactoferrin were soaked in a solution containing dihydroxyphenylalanine (DOPA) and tyrosinase enzyme. These crystals were used for X-ray intensity data collection. The intensity data were collected to 2.7-A resolution to an overall completeness of 91% with an R(sym) of 0.071. The crystals belong to orthorhombic space group P2(1)2(1)2(1) with cell dimensions: a = 85.0 A, b = 99.8 A, c = 103.4 A. The structure was determined by molecular replacement method, using the model of diferric mare lactoferrin, and refined to an R-factor 0.215 (R(free) = 0.287) for all the data to 2.7-A resolution. The final model comprises 5,281 protein atoms from 689 amino acids, 2Fe(3+), 2CO(2-)(3) ions, 2 indole-5,6-quinone molecules (IQ), and 73 water molecules. Two IQ molecules, one in each lobe, bind to lactoferrin. In the C-lobe, the IQ binds in the iron-binding cleft, whereas in the N-lobe, it is located in the side pocket between two alpha-helices, filled with solvent molecules in the native iron-saturated mare lactoferrin. The IQ molecules interact with protein molecule mainly through glutamic acid in both lobes, without significant perturbation to the protein structure. The orientation of N- and C-lobes in the present structure is similar to that observed in the native iron-saturated protein. However, as a result of the binding of IQ molecules, the orientations of the domains N1, N2 and C1, C2 in the two cases differ slightly. Copyright 2001 Wiley-Liss, Inc.

  7. Pigmented epidermal cyst with dense collection of melanin: A rare entity - Report of a case with review of the literature.

    Science.gov (United States)

    Jayalakshmy, P S; Subitha, K; Priya, P V; Johnson, Gerald

    2012-05-01

    Epidermal cyst is a very common benign cystic lesion of the skin. It is usual to find ulceration of the lining epithelium, rupture of the cyst wall with chronic inflammation and foreign body giant cell reaction. But, it is very rare to see an epidermal cyst with marked accumulation of melanin pigment. Only a few cases of pigmented epidermal cyst with dense collection of melanin pigment have been published in the literature. Here, we are reporting a case of ruptured epidermal cyst with keratin granuloma formation and showing dense collection of melanin pigment.

  8. N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

    Science.gov (United States)

    Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

    2017-11-01

    Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

  9. Wavelength-dependent optical properties of melanosomes in retinal pigmented epithelium and their changes with melanin bleaching: a numerical study.

    Science.gov (United States)

    Song, Weiye; Zhang, Lei; Ness, Steve; Yi, Ji

    2017-09-01

    In this paper, we present the first numerical study on full metrics of wavelength-dependent optical properties of melanosomes in retinal pigmented epithelial (RPE) cells. T-matrix method was used to simulate the spheroidal shapes of mature melanosomes, and the complex refractive index was calculated by a subtractive Kramers-Kronig relation for melanin. The validity of the method was first confirmed by Mie theory, and corroborated by a comparison between visible light and near infrared (NIR) optical coherence tomography (OCT) on human retinal imaging. We also studied the changes of melanosome optical properties due to melanin bleaching by numerically reducing the absorption of melanin. This study implies a unique approach to detect melanin changes specifically in RPE by a spectroscopic contrast of optical coherence tomography.

  10. EPR characteristics of free radicals in DOPA-melanin-moxifloxacin complexes at ambient level of UVA radiation

    Science.gov (United States)

    Beberok, Artur; Zdybel, Magdalena; Pilawa, Barbara; Buszman, Ewa; Wrześniok, Dorota

    2014-01-01

    EPR studies pointed out that o-semiquinone free radicals with g-values 2.0038-2.0040 take part in moxifloxacin-melanin complex formation. The process contributed to increase in free radicals concentration in nonirradiated complexes. This effect was observed for the complexes with 1 × 10-4 M, 1 × 10-3 M and 4 × 10-3 M drug concentrations. UV irradiation contributed to decrease in free radicals concentration in DOPA-melanin complexes with moxifloxacin, besides the complexes with the drug concentration of 1 × 10-4 M. The strongest decrease was observed for DOPA-melanin-moxifloxacin complexes with the drug concentration of 1 × 10-3 M. Homogeneous broadening of EPR lines, strong dipolar interactions and slow spin-lattice relaxation processes characterized all the tested melanin samples.

  11. Quantifying melanin distribution using pump-probe microscopy and a 2D morphological autocorrelation transformation for melanoma diagnosis

    Science.gov (United States)

    Robles, Francisco E.; Wilson, Jesse W.; Warren, Warren S.

    2014-03-01

    Pump-probe microscopy is a quantitative molecular imaging technique that yields diagnostically relevant information from endogenous pigments, like melanin, by probing their ultrafast photodynamic properties. Previously, the method was applied to image thin, pigmented, cutaneous samples at different stages of melanoma, and results have shown a correlation between melanin photodynamic behavior and malignancy. Here, we add to the diagnostic power of the method by applying principles of mathematical morphology to parameterize melanins' image structure. Along with bulk melanin chemical information, results show that this method can differentiate invasive melanomas from non-invasive and benign lesions with high sensitivity and specificity (92.3% and 97.5%, respectively, with N = 53). The mathematical method and the statistical analysis are described in detail and results from cutaneous and ocular conjuctival melanocytic lesions are presented.

  12. Topical microemulsion containing Punica granatum extract: its control over skin erythema and melanin in healthy Asian subjects.

    Science.gov (United States)

    Parveen, Rashida; Akhtar, Naveed; Mahmood, Tariq

    2014-12-01

    Punica granatum is apotent source of polyphenolic compounds with strong free radicals scavenging activity. The skin lightening effects of Punica granatum are assumed due to ellagic acid which acts by chelating copper at the active site of tyrosinase. To explore a topical microemulsion (O/W) of pomegranate (Punica granatum) extract for its control on skin erythema and melanin. Microemulsions were formulated using a polysorbate surfactant (Tween 80(®)) along with cosurfactant (propylene glycol) and were characterized regarding their stability. The placebo microemulsion (without extract) and the active microemulsion (containing Punica extract) were applied in a split face fashion by the volunteers (n = 11) for a period of 12 weeks. Skin erythema and melanin were measured at baseline and after every 15 days to determine any effect produced by these formulations. Active formulation showed a significant impact on skin erythema and melanin (p Punica granatum extract for conditions where elevated skin melanin and erythema have significantly prone skin physiology.

  13. Influence of chitosan and melanin-glucan complex onto gamma-exposure with low doses and acute stressful reaction

    International Nuclear Information System (INIS)

    Senyuk, O.F.; Tarasenko, P.D.; Pazukhin, Eh.M.; Gorovoj, L.F.; Varlamov, V.P.

    2004-01-01

    Possibilities of prevention and reduction of consequences of acute exposure on the background of immobilization stress with the help of chitosan preparations and of melanin - glucan complex of highest bazidiomicetes (fungi) were studied. Tested preparations were capable to protect hematological and immunological homeostasis of line BALB/c mice from stressful reaction provoked by acute exposure and two-hour immobilization. The most expressed normalizing and adapting effect had the mixture composed of chitosan and melanin-glucan complex

  14. Loss of Melanin by Eye Retinal Pigment Epithelium Cells Is Associated with Its Oxidative Destruction in Melanolipofuscin Granules.

    Science.gov (United States)

    Dontsov, A E; Sakina, N L; Ostrovsky, M A

    2017-08-01

    The effect of superoxide radicals on melanin destruction and degradation of melanosomes isolated from cells of retinal pigment epithelium (RPE) of the human eye was studied. We found that potassium superoxide causes destruction of melanin in melanosomes of human and bovine RPE, as well as destruction of melanin from the ink bag of squid, with the formation of fluorescent decay products having an emission maximum at 520-525 nm. The initial kinetics of the accumulation of the fluorescent decay products is linear. Superoxide radicals lead simultaneously to a decrease in the number of melanosomes and to a decrease in concentration of paramagnetic centers in them. Complete degradation of melanosomes leads to the formation of a transparent solution containing dissolved proteins and melanin degradation products that do not exhibit paramagnetic properties. To completely degrade one melanosome of human RPE, 650 ± 100 fmol of superoxide are sufficient. The concentration of paramagnetic centers in a melanolipofuscin granule of human RPE is on average 32.5 ± 10.4% (p < 0.05, 150 eyes) lower than in a melanosome, which indicates melanin undergoing a destruction process in these granules. RPE cells also contain intermediate granules that have an EPR signal with a lower intensity than that of melanolipofuscin granules, but higher than that of lipofuscin granules. This signal is due to the presence of residual melanin in these granules. Irradiation of a mixture of melanosomes with lipofuscin granules with blue light (450 nm), in contrast to irradiation of only melanosomes, results in the appearance of fluorescent melanin degradation products. We suggest that one of the main mechanisms of age-related decrease in melanin concentration in human RPE cells is its destruction in melanolipofuscin granules under the action of superoxide radicals formed during photoinduced oxygen reduction by lipofuscin fluorophores.

  15. Reduced yield of x-ray-induced long-lived paramagnetic centers in melanin-containing wool

    Energy Technology Data Exchange (ETDEWEB)

    Latypov, I.F.; Vsevolodov, E.B.; Golichenkov, V.A.

    1979-10-01

    After exposure to x rays in the air at 300/sup 0/K in doses of 60 to 1000 krad, the absolute increment of free radicals (10/sup 16/ spin/g) is several times lower in brown wool (containing melanin) than in pure white wool or white wool to which melanin powder, which is not dispersed in the wool fibers, is added (8.10/sup 16/ spin/g).

  16. Compton scattering by internal shields based on melanin-containing mushrooms provides protection of gastrointestinal tract from ionizing radiation.

    Science.gov (United States)

    Revskaya, Ekaterina; Chu, Peter; Howell, Robertha C; Schweitzer, Andrew D; Bryan, Ruth A; Harris, Matthew; Gerfen, Gary; Jiang, Zewei; Jandl, Thomas; Kim, Kami; Ting, Li-Min; Sellers, Rani S; Dadachova, Ekaterina; Casadevall, Arturo

    2012-11-01

    There is a need for radioprotectors that protect normal tissues from ionizing radiation in patients receiving high doses of radiation and during nuclear emergencies. We investigated the possibility of creating an efficient oral radioprotector based on the natural pigment melanin that would act as an internal shield and protect the tissues via Compton scattering followed by free radical scavenging. CD-1 mice were fed melanin-containing black edible mushrooms Auricularia auricila-judae before 9 Gy total body irradiation. The location of the mushrooms in the body before irradiation was determined by in vivo fluorescent imaging. Black mushrooms protected 80% of mice from the lethal dose, while control mice or those given melanin-devoid mushrooms died from gastrointestinal syndrome. The crypts of mice given black mushrooms showed less apoptosis and more cell division than those in control mice, and their white blood cell and platelet counts were restored at 45 days to preradiation levels. The role of melanin in radioprotection was proven by the fact that mice given white mushrooms supplemented with melanin survived at the same rate as mice given black mushrooms. The ability of melanin-containing mushrooms to provide remarkable protection against radiation suggests that they could be developed into oral radioprotectors.

  17. Fungal melanin stimulates surfactant protein D-mediated opsonization of and host immune response to Aspergillus fumigatus spores.

    Science.gov (United States)

    Sze Wah Wong, Sarah; Rani, Manjusha; Dodagatta-Marri, Eswari; Ibrahim-Granet, Oumaima; Kishore, Uday; Bayry, Jagadeesh; Latgé, Jean-Paul; Sahu, Arvind; Madan, Taruna; Aimanianda, Vishukumar

    2018-02-05

    Surfactant protein D (SP-D), a C-type lectin and pattern-recognition soluble factor, plays an important role in immune surveillance to detect and eliminate human pulmonary pathogens. SPD has been shown to protect against infections with the most ubiquitous airborne fungal pathogen, Aspergillus fumigatus, but the fungal surface component(s) interacting with SP-D is unknown. Here, we show that SP-D binds to melanin pigment on the surface of A. fumigatus dormant spores (conidia). SP-D also exhibited an affinity to two cell-wall polysaccharides of A. fumigatus, galactomannan (GM) and galactosaminogalactan (GAG). The immunolabeling pattern of SP-D was punctate on the conidial surface and was uniform on germinating conidia, in accordance with the localization of melanin, GM, and GAG. We also found that the collagen-like domain of SP-D is involved in its interaction with melanin, whereas its carbohydrate-recognition domain recognized GM and GAG. Unlike unopsonized conidia, SPD-opsonized conidia were phagocytosed more efficiently and stimulated the secretion of proinflammatory cytokines by human monocytederived macrophages. Further, SP-D -/- mice challenged intranasally with wild-type conidia or melanin ghosts (i.e. hollow melanin spheres) displayed significantly reduced proinflammatory cytokines in the lung compared with wild-type mice. In summary, SP-D binds to melanin present on the dormant A. fumigatus conidial surface, facilitates conidial phagocytosis, and stimulates the host immune response. Copyright © 2018, The American Society for Biochemistry and Molecular Biology.

  18. Statistical analysis on activation and photo-bleaching of step-wise multi-photon activation fluorescence of melanin

    Science.gov (United States)

    Gu, Zetong; Lai, Zhenhua; Zhang, Xi; Yin, Jihao; DiMarzio, Charles A.

    2015-03-01

    Melanin is regarded as the most enigmatic pigments/biopolymers found in most organisms. We have shown previously that melanin goes through a step-wise multi-photon absorption process after the fluorescence has been activated with high laser intensity. No melanin step-wise multi-photon activation fluorescence (SMPAF) can be obtained without the activation process. The step-wise multi-photon activation fluorescence has been observed to require less laser power than what would be expected from a non-linear optical process. In this paper, we examined the power dependence of the activation process of melanin SMPAF at 830nm and 920nm wavelengths. We have conducted research using varying the laser power to activate the melanin in a point-scanning mode for multi-photon microscopy. We recorded the fluorescence signals and position. A sequence of experiments indicates the relationship of activation to power, energy and time so that we can optimize the power level. Also we explored regional analysis of melanin to study the spatial relationship in SMPAF and define three types of regions which exhibit differences in the activation process.

  19. Melanin- and carotenoid-dependent signals of great tits ( Parus major) relate differently to metal pollution

    Science.gov (United States)

    Dauwe, Tom; Eens, Marcel

    2008-10-01

    Due to their high phenotypic plasticity, the expression of secondary sexual characteristics is particularly sensitive to stress. Here, we investigated the expression of two conspicuous visual signals in great tits ( Parus major) in a metal pollution gradient. In three study sites with marked differences in metal contamination (mainly lead, cadmium, copper and zinc), we compared melanin and carotenoid colouration of great tits. While carotenoid colouration (yellow breast) was negatively related to metal pollution, the size of a melanin trait (breast stripe) was larger in the most polluted sites. Environmental pollutants not only affect the expression of conspicuous signals but may even enhance, directly or indirectly, a signal of male quality such as breast stripe. Our results also support the multiple messages hypothesis predicting that different signals highlight different aspects of geno- and phenotypic condition of the bearer.

  20. Antioxidative role of ocular melanin pigment in the model of lens induced uveitis.

    Science.gov (United States)

    Bilgihan, A; Bilgihan, M K; Akata, R F; Aricioğlu, A; Hasanreisoğlu, B

    1995-12-01

    Ocular melanin pigment has antioxidant effect against excess of dispersed light. To investigate whether it has a similar effect in ocular inflammations, we used albino and pigmented guinea pigs and measured retinal glutathione peroxidase activities and lipid peroxide levels (expressed as thiobarbituric acid reactive substances) in a model of lens induced uveitis. Although the increase in the levels of the retinal lipid peroxides were higher in the albino group (204%, p < 0.05), the decrease in the activities of glutathione peroxidase were higher in pigmented guinea pigs (26%, p < 0.005). The results of the study suggest that pigmentless animals are more sensitive to the ocular inflammations, and ocular melanin pigment may act as an endojen antioxidant in lens induced uveitis.

  1. AP-1/KIF13A Blocking Peptides Impair Melanosome Maturation and Melanin Synthesis.

    Science.gov (United States)

    Campagne, Cécile; Ripoll, Léa; Gilles-Marsens, Floriane; Raposo, Graça; Delevoye, Cédric

    2018-02-14

    Melanocytes are specialized cells that generate unique organelles called melanosomes in which melanin is synthesized and stored. Melanosome biogenesis and melanocyte pigmentation require the transport and delivery of melanin synthesizing enzymes, such as tyrosinase and related proteins (e.g., TYRP1), from endosomes to maturing melanosomes. Among the proteins controlling endosome-melanosome transport, AP-1 together with KIF13A coordinates the endosomal sorting and trafficking of TYRP1 to melanosomes. We identify here β1-adaptin AP-1 subunit-derived peptides of 5 amino acids that block the interaction of KIF13A with AP-1 in cells. Incubating these peptides with human MNT-1 cells or 3D-reconstructed pigmented epidermis decreases pigmentation by impacting the maturation of melanosomes in fully pigmented organelles. This study highlights that peptides targeting the intracellular trafficking of melanocytes are candidate molecules to tune pigmentation in health and disease.

  2. AP-1/KIF13A Blocking Peptides Impair Melanosome Maturation and Melanin Synthesis

    Directory of Open Access Journals (Sweden)

    Cécile Campagne

    2018-02-01

    Full Text Available Melanocytes are specialized cells that generate unique organelles called melanosomes in which melanin is synthesized and stored. Melanosome biogenesis and melanocyte pigmentation require the transport and delivery of melanin synthesizing enzymes, such as tyrosinase and related proteins (e.g., TYRP1, from endosomes to maturing melanosomes. Among the proteins controlling endosome-melanosome transport, AP-1 together with KIF13A coordinates the endosomal sorting and trafficking of TYRP1 to melanosomes. We identify here β1-adaptin AP-1 subunit-derived peptides of 5 amino acids that block the interaction of KIF13A with AP-1 in cells. Incubating these peptides with human MNT-1 cells or 3D-reconstructed pigmented epidermis decreases pigmentation by impacting the maturation of melanosomes in fully pigmented organelles. This study highlights that peptides targeting the intracellular trafficking of melanocytes are candidate molecules to tune pigmentation in health and disease.

  3. Relationship between p-boronophenylalanine and polymerization of melanin monomers in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kamijyo, M.; Yoshino, Kazuo [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Kondo, H.; Kadota, M.; Mishima, Y.

    1998-12-01

    p-boronophenylalanine (p-BPA) is now employed in Boron Neutron Capture Therapy (BNCT) for cancer. However, it has been confirmed that {sup 10}B content accumulated in melanomas decreases with time. It is suggested that p-BPA has suppressive ability for the formation of the melanin polymer substrate which would stabilize the p-BPA taken in. To make clear the mechanism for this, the present authors investigated chemical reactions taking place in the DOPA chrome solution added with p-BPA using {sup 11}B-NMR method. It was concluded that p-BPA when complexed with dihydroxy derivatives of melanin precursors (L-DOPA, DHICA) reacts with dissolved oxygen to give boric acid and tyrosine. Effects of the pH and the concentration of DOPA chrome on the reaction were also studied. (S. Ohno)

  4. Genetic monitoring of experimental Drosophila populations exposed to X-radiation and treated with melanin

    International Nuclear Information System (INIS)

    Mosseh, I.B.; Savchenko, V.K.; Lyakh, I.P.

    1985-01-01

    Monitoring of laboratory populations of Drosophila over four years has demonstrated that X radiation of 0.25 C/kg, delivered during the life span of each generation, causes a decrease of 20% and 30%, on the average, in the number of individuals in 1-55 generations and 45-55 generations, respectively. The antimutagen, melanin, added to a nutrient medium has no effect on the number of individuals in populations

  5. Melanocytes and melanin represent a first line of innate immunity against Candida albicans.

    Science.gov (United States)

    Tapia, Cecilia V; Falconer, Maryanne; Tempio, Fabián; Falcón, Felipe; López, Mercedes; Fuentes, Marisol; Alburquenque, Claudio; Amaro, José; Bucarey, Sergio A; Di Nardo, Anna

    2014-07-01

    Melanocytes are dendritic cells located in the skin and mucosae that synthesize melanin. Some infections induce hypo- or hyperpigmentation, which is associated with the activation of Toll-like receptors (TLRs), especially TLR4. Candida albicans is an opportunist pathogen that can switch between blastoconidia and hyphae forms; the latter is associated with invasion. Our objectives in this study were to ascertain whether C. albicans induces pigmentation in melanocytes and whether this process is dependent on TLR activation, as well as relating this with the antifungal activity of melanin as a first line of innate immunity against fungal infections. Normal human melanocytes were stimulated with C. albicans supernatants or with crude extracts of the blastoconidia or hyphae forms, and pigmentation and TLR2/TLR4 expression were measured. Expression of the melanosomal antigens Melan-A and gp100 was examined for any correlation with increased melanin levels or antifungal activity in melanocyte lysates. Melanosomal antigens were induced earlier than cell pigmentation, and hyphae induced stronger melanization than blastoconidia. Notably, when melanocytes were stimulated with crude extracts of C. albicans, the cell surface expression of TLR2/TLR4 began at 48 h post-stimulation and peaked at 72 h. At this time, blastoconidia induced both TLR2 and TLR4 expression, whereas hyphae only induced TLR4 expression. Taken together, these results suggest that melanocytes play a key role in innate immune responses against C. albicans infections by recognizing pathogenic forms of C. albicans via TLR4, resulting in increased melanin content and inhibition of infection. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Simultaneous estimation of transcutaneous bilirubin, hemoglobin, and melanin based on diffuse reflectance spectroscopy

    Science.gov (United States)

    Nishidate, Izumi; Abdul, Wares MD.; Ohtsu, Mizuki; Nakano, Kazuya; Haneishi, Hideaki

    2018-02-01

    We propose a method to estimate transcutaneous bilirubin, hemoglobin, and melanin based on the diffuse reflectance spectroscopy. In the proposed method, the Monte Carlo simulation-based multiple regression analysis for an absorbance spectrum in the visible wavelength region (460-590 nm) is used to specify the concentrations of bilirubin (Cbil), oxygenated hemoglobin (Coh), deoxygenated hemoglobin (Cdh), and melanin (Cm). Using the absorbance spectrum calculated from the measured diffuse reflectance spectrum as a response variable and the extinction coefficients of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, as predictor variables, multiple regression analysis provides regression coefficients. Concentrations of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, are then determined from the regression coefficients using conversion vectors that are numerically deduced in advance by the Monte Carlo simulations for light transport in skin. Total hemoglobin concentration (Cth) and tissue oxygen saturation (StO2) are simply calculated from the oxygenated hemoglobin and deoxygenated hemoglobin. In vivo animal experiments with bile duct ligation in rats demonstrated that the estimated Cbil is increased after ligation of bile duct and reaches to around 20 mg/dl at 72 h after the onset of the ligation, which corresponds to the reference value of Cbil measured by a commercially available transcutaneous bilirubin meter. We also performed in vivo experiments with rats while varying the fraction of inspired oxygen (FiO2). Coh and Cdh decreased and increased, respectively, as FiO2 decreased. Consequently, StO2 was dramatically decreased. The results in this study indicate potential of the method for simultaneous evaluation of multiple chromophores in skin tissue.

  7. Conidial Dihydroxynaphthalene Melanin of the Human Pathogenic Fungus Aspergillus fumigatus Interferes with the Host Endocytosis Pathway.

    Science.gov (United States)

    Thywißen, Andreas; Heinekamp, Thorsten; Dahse, Hans-Martin; Schmaler-Ripcke, Jeannette; Nietzsche, Sandor; Zipfel, Peter F; Brakhage, Axel A

    2011-01-01

    Aspergillus fumigatus is the most important air-borne fungal pathogen of humans. The interaction of the pathogen with the host's immune system represents a key process to understand pathogenicity. For elimination of invading microorganisms, they need to be efficiently phagocytosed and located in acidified phagolysosomes. However, as shown previously, A. fumigatus is able to manipulate the formation of functional phagolysosomes. Here, we demonstrate that in contrast to pigmentless pksP mutant conidia of A. fumigatus, the gray-green wild-type conidia inhibit the acidification of phagolysosomes of alveolar macrophages, monocyte-derived macrophages, and human neutrophil granulocytes. Therefore, this inhibition is independent of the cell type and applies to the major immune effector cells required for defense against A. fumigatus. Studies with melanin ghosts indicate that the inhibitory effect of wild-type conidia is due to their dihydroxynaphthalene (DHN)-melanin covering the conidia, whereas the hydrophobin RodA rodlet layer plays no role in this process. This is also supported by the observation that pksP conidia still exhibit the RodA hydrophobin layer, as shown by scanning electron microscopy. Mutants defective in different steps of the DHN-melanin biosynthesis showed stronger inhibition than pksP mutant conidia but lower inhibition than wild-type conidia. Moreover, A. fumigatus and A. flavus led to a stronger inhibition of phagolysosomal acidification than A. nidulans and A. terreus. These data indicate that a certain type of DHN-melanin that is different in the various Aspergillus species, is required for maximal inhibition of phagolysosomal acidification. Finally, we identified the vacuolar ATPase (vATPase) as potential target for A. fumigatus based on the finding that addition of bafilomycin which inhibits vATPase, led to complete inhibition of the acidification whereas the fusion of phagosomes containing wild-type conidia and lysosomes was not affected.

  8. Two-photon excited fluorescence spectroscopy and imaging of melanin in vitro and in vivo

    Science.gov (United States)

    Krasieva, Tatiana B.; Liu, Feng; Sun, Chung-Ho; Kong, Yu; Balu, Mihaela; Meyskens, Frank L.; Tromberg, Bruce J.

    2012-03-01

    The ability to detect early melanoma non-invasively would improve clinical outcome and reduce mortality. Recent advances in two-photon excited fluorescence (TPEF) in vivo microscopy offer a powerful tool in early malignant melanoma diagnostics. The goal of this work was to develop a TPEF optical index for measuring relative concentrations of eumelanin and pheomelanin since ex vivo studies show that changes in this ratio have been associated with malignant transformation. We acquired TPEF emission spectra (λex=1000 nm) of melanin from several specimens, including human hair, malignant melanoma cell lines, and normal melanocytes and keratinocytes in different skin layers (epidermis, papillary dermis) in five healthy volunteers in vivo. We found that the pheomelanin emission peaks at around 620 nm and is blue-shifted from the eumelanin with broad maximum at 640-680nm. We defined "optical melanin index" (OMI) as a ratio of fluorescence signal intensities measured at 645 nm and 615nm. The measured OMI for a melanoma cell line MNT-1 was 1.6+/-0.2. The MNT-46 and MNT-62 lines (Mc1R gene knockdown) showed an anticipated change in melanins production ratio and had OMI of 0.55+/-0.05 and 0.17+/-0.02, respectively, which strongly correlated with HPLC data obtained for these lines. Average OMI measured for basal cells layers (melanocytes and keratinocytes) in normal human skin type I, II-III (not tanned and tanned) in vivo was 0.5, 1.05 and 1.16 respectively. We could not dependably detect the presence of pheomelanin in highly pigmented skin type V-VI. These data suggest that a non-invasive TPEF index could potentially be used for rapid melanin ratio characterization both in vitro and in vivo, including pigmented lesions.

  9. Effects of wogonin on the mechanism of melanin synthesis in A375 cells.

    Science.gov (United States)

    Chen, Xi; Gu, Ting; Wang, Jing-Hua; Xiong, Hui; Wang, Ye-Qiu; Liu, Guo-Liang; Qu, Yan; Zhang, Ning

    2017-11-01

    The present study aimed to investigate the effect of wogonin on the mechanism of melanin synthesis in the A375 melanoma cell line. A375 cells, cultured in vitro , were treated with wogonin and the activity of tyrosinase (TYR) and melanin synthesis were examined via MTT assay, L-dopa oxidation assay and an NaOH lysis assay. Protein expression levels of TYR and c-Jun N-terminal kinase (JNK) were examined via western blotting. mRNA expression levels of TYR, tyrosinase related protein (TRP)-1, TRP-2, extracellular signal-regulated kinase (ERK)-1, ERK-2 and JNK-2 were analyzed by reverse transcription-quantitative polymerase chain reaction. Furthermore, the effect of wogonin on estrogen receptor inhibitor (ICI182780) and ERK pathway inhibitor (U0126) was investigated. Safe doses of wogonin (10, 1, 10 -1 , 10 -2 or 10 -3 µmol/l) significantly inhibited melanin synthesis and TYR activity (P<0.05). Wogonin (10 µmol/l) inhibited the protein expression levels of TYR, JNK and mRNA expression levels of TYR, TRP-1, TRP-2, ERK-1, ERK-2, JNK-2 in A375 cells (P<0.01). The estrogen receptor inhibitor, ICI182780, and MEK inhibitor, U0126, significantly reversed the effects of wogonin on protein and mRNA expression levels of TYR, TRP-1, TRP-2, ERK-1, ERK-2 and JNK-2 (all P<0.01). To conclude, the present study identified that wogonin is able to inhibit the synthesis of melanin in A375 cells, through inhibiting protein and mRNA expression levels of TYR, TRP-1, and TRP-2, and ERK1, ERK2 and JNK2, respectively.

  10. Sulfitolytic and keratinolytic potential of Chryseobacterium sp. RBT revealed hydrolysis of melanin containing feathers

    OpenAIRE

    Gurav, Ranjit G.; Tang, Jingchun; Jadhav, Jyoti P.

    2016-01-01

    In black feathers, melanin is embedded in keratin matrix that makes feather more resistance to the microbial degradation. Chryseobacterium sp. RBT previously isolated from the poultry waste disposable site revealed strong sulfitolytic and keratinolytic activities. Maximum keratinase activity was observed at 48?h (89.12?U?ml?1) showed 83?% of native black feather degradation. The concentration of free sulfhydryl groups released during degradation was 0.648???10?4?M?(12?h), 2.144???10?4?M?(96?h...

  11. Identification of a tyrosinase gene and its functional analysis in melanin synthesis of Pteria penguin.

    Science.gov (United States)

    Yu, Feifei; Pan, Zhenni; Qu, Bingliang; Yu, Xiangyong; Xu, Kaihang; Deng, Yuewen; Liang, Feilong

    2018-02-26

    Tyrosinase is a key rate-limiting enzyme in melanin synthesis. In this study, a new tyrosinase gene (Tyr) was identified from Pteria penguin and its effect on melanin synthesis was deliberated by RNA interference (RNAi). The cDNA of PpTyr was 1728 bp long, containing a 5'untranslated region (UTR) of 11 bp, a 3'UTR of 295 bp, and an open reading fragment of 1422 bp encoding 473 amino acids. Amino acid alignment showed PpTyr had the highest (50%) identity to tyrosinase-like protein 1 from Pinctada fucata. Phylogenetic tree analysis classified PpTyr into α-subclass of type-3 copper protein. Tissue expression analysis indicated that PpTyr was highly expressed in mantle, a nacre formation related tissue. After PpTyr RNA interference, PpTyr mRNA was significantly inhibited by 71.0% (P PDCA (pyrrole-2, 3-dicarboxylic acid) and PTCA (pyrrole-2,3,5-tricarboxylic acid), as main markers for eumelanin, was sharply decreased by 66.6% after PpTyr RNAi (P PDCA was also obviously decreased from 20.1% to 13.9%. This indicated that tyrosinase played a key role in melanin synthesis and color formation of P. penguin. Copyright © 2017. Published by Elsevier B.V.

  12. Substantial Effect of Melanin Influencing Factors on Melanogenesis in Muzzle Melanocytes of Differently Colored Hanwoo

    Directory of Open Access Journals (Sweden)

    Touseef Amna

    2012-07-01

    Full Text Available The present study was designed to investigate the effect of α-melanocyte-stimulating hormone (α-MSH, nitric oxide (NO and L-cysteine on melanin production and expression of related genes MC1R, Tyr, Tyrp-1 and Tyrp-2 in muzzle melanocytes of differently colored three native Hanwoo cattle. Muzzle samples were taken from black, brindle and brown Hanwoo and purified melanocytes were cultured with α-MSH, nitric oxide and L-cysteine at 100 nM, 50 µM and 0.07 mg/ml of media respectively. The amounts of total melanin, eumelanin and mRNA expression at Tyr, Tyrp-1, Tyrp-2 and MC1R levels were quantified. α-MSH and nitric oxide significantly increased (p<0.05 the amount of total melanin in black and brindle whereas eumelanin production in brown Hanwoo muzzle melanocytes. On the contrary, L-cysteine greatly (p<0.05 depressed the eumelanin production in black color but increased in brown. Simultaneously, up regulation of Tyr by nitric oxide and α-MSH and down regulation of Tyr, Tyrp-2 and MC1R genes by L-cysteine were observed in muzzle melanocytes of all three phenotypes. The results of this study revealed nitric oxide and α-MSH contribute hyper-pigmentation by enhancing eumelanogenesis whereas L-cysteine contributes to pheomelanin production in different colored Hanwoo muzzle melanocytes.

  13. Melanin pigments in the melanocytic nevus regress spontaneously after inactivation by high hydrostatic pressure.

    Directory of Open Access Journals (Sweden)

    Michiharu Sakamoto

    Full Text Available We report a novel treatment for giant congenital melanocytic nevi (GCMN that involves the reuse of resected nevus tissue after high hydrostatic pressurization (HHP. However, the remaining melanin pigments in the inactivated nevus tissue pose a problem; therefore, we performed a long-term observation of the color change of inactivated nevus tissue after HHP. Pressurized nevus specimens (200 MPa group, n = 9 and non-pressurized nevus tissues (control group, n = 9 were subcutaneously implanted into nude mice (BALB/c-nu and then harvested 3, 6, and 12 months later. Color changes of the nevus specimens were evaluated. In the 200 MPa group, the specimen color gradually regressed and turned white, and brightness values were significantly higher in the 200 MPa group than in the control group after 6 months. This indicated that melanin pigments in the pressurized nevus tissue had spontaneously degraded and regressed. Therefore, it is not necessary to remove melanin pigments in HHP-treated nevus tissue.

  14. LIGHT REGULATION OF GROWTH AND MELANIN FORMATION IN Inonotus оbliquus (Pers. Pilat

    Directory of Open Access Journals (Sweden)

    N. L. Poyedinok

    2013-04-01

    Full Text Available The study aims to investigate possibilities of using different sources of low-intensity light for the regulation of mycelium growth and melanin synthesis by medicinal mushroom Inonotus obliquus (Pers. Pilat. Studies of the light’s influence on the linear growth, biomass accumulation and melanin synthesis I. obliquus were performed using experimental installations that provide both lasing (coherent light with specified parameters, as well as sources of incoherent light. It has been demonstrated that the greatest stimulating effect took place during the irradiation of mycelium with blue light. It has been found that further realization of photobiological effect is largely dependent on the method of cultivation. Irradiation with laser light within all studied wavelength ranges was more conducive to growth, biomass and melanin accumulation in the mushroom mycelium than incoherent light irradiation within the same wavelength range. Light treatment made it possible to significantly reduce the duration of fermentation. The results of studies allow considering lowintensity light in the visible part of the spectrum as a perspective growth and biosynthetic activity regulator of I. obliquus in the biotechnology of its cultivation.

  15. ULK1 regulates melanin levels in MNT-1 cells independently of mTORC1.

    Directory of Open Access Journals (Sweden)

    Eyal Kalie

    Full Text Available Melanosomes are lysosome-related organelles that serve as specialized sites of melanin synthesis and storage in melanocytes. The progression of melanosomes through the different stages of their formation requires trafficking of specific proteins and membrane constituents in a sequential manner, which is likely to deploy ubiquitous cellular machinery along with melanocyte-specific proteins. Recent evidence revealed a connection between melanogenesis and the autophagy machinery, suggesting a novel role for members of the latter in melanocytes. Here we focused on ULK1, a key autophagy protein which is negatively regulated by mTORC1, to assess its potential role in melanogenesis in MNT-1 cells. We found that ULK1 depletion causes an increase in melanin levels, suggesting an inhibitory function for this protein in melanogenesis. Furthermore, this increase was accompanied by increased transcription of MITF (microphthalmia-associated transcription factor and tyrosinase and by elevated protein levels of tyrosinase, the rate-limiting factor in melanin biogenesis. We also provide evidence to show that ULK1 function in this context is independent of the canonical ULK1 autophagy partners, ATG13 and FIP200. Furthermore we show that regulation of melanogenesis by ULK1 is independent of mTORC1 inhibition. Our data thus provide intriguing insights regarding the involvement of the key regulatory autophagy machinery in melanogenesis.

  16. Multi-spectral mapping of in vivo skin hemoglobin and melanin

    Science.gov (United States)

    Jakovels, Dainis; Spigulis, Janis; Saknite, Inga

    2010-04-01

    The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxyhemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500-700 nm, so speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-hemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy-hemoglobin absorption and exponential function - for melanin absorption. The proposed approach was clinically tested for three types of in-vivo skin provocations - ultraviolet irradiance, chemical reaction with vinegar essence and finger arterial occlusion. Spectral range 500-700 nm provided better sensitivity to oxy-hemoglobin changes and higher response stability to melanin than two reduced ranges 500-600 nm and 530-620 nm.

  17. Sesquiterpenes from fruits of Torilis japonica with inhibitory activity on melanin synthesis in B16 cells.

    Science.gov (United States)

    Song, Da Hye; Jo, Yang Hee; Ahn, Jong Hoon; Kim, Seon Beom; Yun, Cheong-Yong; Kim, Youngsoo; Hwang, Bang Yeon; Lee, Mi Kyeong

    2018-01-01

    Melanin, a dark macromolecular pigment, protects skin from harmful damage. However, abnormal accumulation is responsible for hyperpigmentation disorders. Melanogenesis inhibitors have therefore become important constituents in cosmetic products for depigmentation. Torilis japonica Decandolle (Umbelliferae) is a biennial plant which is distributed in East Asia. Fruits of this plant have been used for the treatment of skin disease and inflammation. In our previous study, torilin, a major sesquiterpene of T. japonica, showed an inhibitory effect on melanin production in α-melanocyte stimulating hormone (α-MSH)-activated B16 melanoma cells. Further extensive chromatographic separation resulted in thirteen compounds. On the basis of spectroscopic analysis, the structures of the compounds isolated were determined to be three new sesquiterpenes, viz. a guaiane-type, epoxytorilinol (1), a eudesmane-type, elematorilone (2) and a cadinane-type, cardinatoriloside (3), together with ten known sesquiterpenes (4-13). Of the compounds isolated, compounds 4-6 and 11-13 inhibited α-MSH-activated melanin production in B16 melanoma cells with IC 50 values from 72.9 to 191.0 μM.

  18. Melanin granule model for laser-induced thermal damage in the retina

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C.R.; Rogers, M.E. [Armstrong Laboratory, Brooks AFB, TX (United States). Optical Radiation Division; Gerstman, B.S. [Florida International Univ., Miami, FL (United States). Physics Dept.; Jacques, S.L. [M.D. Anderson Cancer Center, Houston, TX (United States). Laser Biology Research Lab.

    1996-05-01

    An analytical model for thermal damage of retinal tissue due to absorption of laser energy by finite-sized melanin granules is developed. Since melanin is the primary absorber of visible and near-IR light in the skin and in the retina, bulk heating of tissue can be determined by superposition of individual melanin granule effects. Granules are modeled as absorbing spheres surrounded by an infinite medium of water. Analytical solutions to the heat equation result in computations that are quick and accurate. Moreover, the model does not rely on symmetric beam profiles, and so arbitrary images can be studied. The important contribution of this model is to provide a more accurate biological description of submillisecond pulse exposures than previous retinal models, while achieving agreement for longer pulses. This model can also be naturally extended into the sub-microsecond domain by including vaporization as a damage mechanism. It therefore represents the beginning of a model which can be applied across the entire pulse duration domain.

  19. Three-photon fluorescence imaging of melanin with a dual-wedge confocal scanning system

    Science.gov (United States)

    Mega, Yair; Kerimo, Joseph; Robinson, Joseph; Vakili, Ali; Johnson, Nicolette; DiMarzio, Charles

    2012-03-01

    Confocal microscopy can be used as a practical tool in non-invasive applications in medical diagnostics and evaluation. In particular, it is being used for the early detection of skin cancer to identify pathological cellular components and, potentially, replace conventional biopsies. The detection of melanin and its spatial location and distribution plays a crucial role in the detection and evaluation of skin cancer. Our previous work has shown that the visible emission from melanin is strong and can be easily observed with a near-infrared CW laser using low power. This is due to a unique step-wise, (SW) three-photon excitation of melanin. This paper shows that the same SW, 3-photon fluorescence can also be achieved with an inexpensive, continuous-wave laser using a dual-prism scanning system. This demonstrates that the technology could be integrated into a portable confocal microscope for clinical applications. The results presented here are in agreement with images obtained with the larger and more expensive femtosecond laser system used earlier.

  20. Effect of oxygen on free radicals in DOPA-melanin complexes with netilmicin, diamagnetic Zn(II), and paramagnetic Cu(II)

    Science.gov (United States)

    Zdybel, Magdalena; Pilawa, Barbara; Buszman, Ewa; Wrześniok, Dorota

    2013-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used to examine interactions between molecules of oxygen O2 and free radicals of DOPA-melanin and its complexes with netilmicin, Zn(II) and Cu(II). EPR spectra were measured for evacuated samples and then compared to earlier data for the samples in air. The concentrations of free radicals in the evacuated samples were higher than for samples in air. The strongest effect was observed for DOPA-melanin and melanin samples containing Cu(II). Evacuation of DOPA-melanin and DOPA-melanin-Cu(II) samples causes high EPR line broadening. Faster spin-lattice relaxation processes exist in evacuated melanin samples than in samples in air.

  1. Penurunan Aktivitas Tirosinase dan Jumlah Melanin oleh Fraksi Etil Asetat Buah Malaka (Phyllantus emblica) pada Mouse Melanoma B16 Cell-Line

    OpenAIRE

    Reti Hindritiani; Diah Dhianawaty; Muchtan Sujatno; Endang Sutedja; Setiawan

    2013-01-01

    Melanin accumulation can lead to hyperpigmentation, and if it occurs on the face can cause psychosocial problem. Depigmenting agents derived from plants are increasingly utilized. Agents being developed have to be effective in inhibiting melanin synthesis and should not be toxic to melanocyte. This study aimed was to examine the effect of ethyl acetate fraction from Phyllanthus emblica (P. emblica) fruit, also known as malaka fruit, towards melanine synthesis, which was measured from the mela...

  2. Melanin is an essential component for the integrity of the cell wall of Aspergillus fumigatus conidia

    Directory of Open Access Journals (Sweden)

    Georgeault Sonia

    2009-08-01

    Full Text Available Abstract Background Aspergillus fumigatus is the most common agent of invasive aspergillosis, a feared complication in severely immunocompromised patients. Despite the recent commercialisation of new antifungal drugs, the prognosis for this infection remains uncertain. Thus, there is a real need to discover new targets for therapy. Particular attention has been paid to the biochemical composition and organisation of the fungal cell wall, because it mediates the host-fungus interplay. Conidia, which are responsible for infections, have melanin as one of the cell wall components. Melanin has been established as an important virulence factor, protecting the fungus against the host's immune defences. We suggested that it might also have an indirect role in virulence, because it is required for correct assembly of the cell wall layers of the conidia. Results We used three A. fumigatus isolates which grew as white or brown powdery colonies, to demonstrate the role of melanin. Firstly, sequencing the genes responsible for biosynthesis of melanin (ALB1, AYG1, ARP1, ARP2, ABR1 and ABR2 showed point mutations (missense mutation, deletion or insertion in the ALB1 gene for pigmentless isolates or in ARP2 for the brownish isolate. The isolates were then shown by scanning electron microscopy to produce numerous, typical conidial heads, except that the conidia were smooth-walled, as previously observed for laboratory mutants with mutations in the PKSP/ALB1 gene. Flow cytometry showed an increase in the fibronectin binding capacity of conidia from mutant isolates, together with a marked decrease in the binding of laminin to the conidial surface. A marked decrease in the electronegative charge of the conidia and cell surface hydrophobicity was also seen by microelectrophoresis and two-phase partitioning, respectively. Ultrastructural studies of mutant isolates detected considerable changes in the organisation of the conidial wall, with the loss of the outermost

  3. [Decolorization of skin and hair-derived melanin by three ligninolytic enzymes].

    Science.gov (United States)

    Miao, F; Lei, T C; Su, M Y; Yi, W J; Jiang, S; Xu, S Z

    2017-11-21

    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 (0.2 U/ml) of ligninolytic enzymes for 3 h respectively.The absorbance at 475 nm ( A (475)) in the enzyme-catalyzed solution was measured using ELISA microplate reader.The experimental hyperpigmentation model was established in the dorsal skin of brownish guinea pigs using 308 nm excimer light radiation.LiP and heat-inactivated LiP solution were topically applied at each site.Meanwhile, 3% hydroquinone and vehicle cream were used as control.The skin color (L value) was recorded using a CR-10 Minolta chromameter.Corneocytes were collected using adhesive taping method.The amount and distribution of melanin in the corneocytes and skin tissues was visualized by Fontana-Masson staining. Results: All three ligninolytic enzymes showed various degree of eumelanin and pheomelanin decolorization activity.The decolorization activity of LiP, MnP and laccase was 40%-70%, 22%-42% and 9%-21%, respectively.The similar lightening was shown in the skin treated with LiP solution and 3% hydroquinone.The amount of melanin granules in the corneocytes was 199±11 by LiP, which was less than that in untreated control (923±12) and heat-inactive control (989±13). The amount of melanin was decreased in the whole epidermis treated with hydroquinone, the epidermis thickness was increased as well. In contrast, melanin of LiP group was decreased only in the superficial epidermis, the epidermis thickness seemed to be normal. Conclusion: LiP exerts

  4. Melanin-embedded materials effectively remove hexavalent chromium (CrVI) from aqueous solution.

    Science.gov (United States)

    Cuong, An Manh; Le Na, Nguyen Thi; Thang, Pham Nhat; Diep, Trinh Ngoc; Thuy, Ly Bich; Thanh, Nguyen Lai; Thang, Nguyen Dinh

    2018-02-23

    Currently, it is recognized that water polluted with toxic heavy metal ions may cause serious effects on human health. Therefore, the development of new materials for effective removal of heavy metal ions from water is still a widely important area. Melanin is being considered as a potential material for removal of heavy metal from water. In this study, we synthesized two melanin-embedded beads from two different melanin powder sources and named IMB (Isolated Melanin Bead originated from squid ink sac) and CMB (Commercial Melanin Bead originated from sesame seeds). These beads were of globular shape and 2-3 mm in diameter. We investigated and compared the sorption abilities of these two bead materials toward hexavalent-chromium (Cr VI ) in water. The isotherm sorption curves were established using Langmuir and Freundlich models in the optimized conditions of pH, sorption time, solid/liquid ratio, and initial concentration of Cr VI . The FITR analysis was also carried out to show the differences in surface properties of these two beads. The optimized conditions for isotherm sorption of Cr VI on IMB/CMB were set at pH values of 2/2, sorption times of 90/300 min, and solid-liquid ratios of 10/20 mg/mL. The maximum sorption capacities calculated based on the Langmuir model were 19.60 and 6.24 for IMB and CMB, respectively. However, the adsorption kinetic of Cr VI on the beads fitted the Freundlich model with R 2 values of 0.992 for IMB and 0.989 for CMB. The deduced Freundlich constant, 1/n, in the range of 0.2-0.8 indicated that these beads are good adsorption materials. In addition, structure analysis data revealed great differences in physical and chemical properties between IMB and CMB. Interestingly, FTIR analysis results showed strong signals of -OH (3295.35 cm - 1 ) and -C=O (1608.63 cm - 1 ) groups harboring on the IMB but not CMB. Moreover, loading of Cr VI on the IMB caused a shift of broad peaks from 3295.35 cm - 1 and 1608.63 cm - 1 to 3354

  5. Mechanical and photo-fragmentation processes for nanonization of melanin to improve its efficacy in protecting cells from reactive oxygen species stress

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi-Cheng [Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Chen, Sih-Min [Graduate Institute of Biophysics, National Central University, Jhongli 32001, Taiwan (China); Liu, Jhong-Han; Hsu, Hsiang-Wei [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Lin, Hoang-Yan [Graduate Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chen, Szu-yuan, E-mail: sychen@ltl.iams.sinica.edu.tw [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Graduate Institute of Biophysics, National Central University, Jhongli 32001, Taiwan (China); Department of Physics, National Central University, Jhongli 32001, Taiwan (China)

    2015-02-14

    It has been well established ex vivo that melanin has the ability of scavenging free radicals and reactive oxygen species (ROS), besides other functions. Therefore, we propose to utilize nanonized melanin as medication against acute oxidative stress. For this purpose, we developed and characterized two techniques based on mechanical stir and photo-fragmentation using femtosecond laser pulses, respectively, for disintegration of suspended melanin powder to produce nanometer-sized and water-dispersible melanin. This resolves a major obstacle in the medical and industrial applications of melanin. The viabilities of cultured retinal pigment epithelium (RPE) cells exposed to exogenous H{sub 2}O{sub 2} stress and treated with various conditions of melanin and irradiation were compared. It was found that melanin could be nanonized very effectively with the techniques, and nanonized melanin exhibited a much stronger effect than unprocessed melanin on raising the viability of cultured RPE cells under acute ROS stress. The effect was even more prominent without simultaneous light irradiation, promising for effective in vivo application to the whole body.

  6. The effect of endo- and exogenous melanin on Zn{sup 2+} and Co{sup 2+} elimination and distribution in mice

    Energy Technology Data Exchange (ETDEWEB)

    Nogaj, P.; Buszman, E.; Swiatkowska, L.; Wilczok, T. [Slaska Akademia Medyczna, Katowice (Poland)

    1995-12-31

    The content of endogenous melanin in white Balb c and black C-57 Bl. mice affected Zn{sup 2+} and Co{sup 2+} accumulation, elimination and distribution following intraperitoneal administration of these ions. Elimination of Co{sup 2+} ions was significantly greater in white mice than in black mice. Accumulation of Zn{sup 2+} was higher than that of Co{sup 2+} and did not depend on melanin content in mice. The same response was observed upon administration of exogenous melanin. Both ions accumulated mainly in spleen and heart irrespective of melanin content. (author). 12 refs, 4 figs, 3 tabs.

  7. 3, 4-dihydroxy-L-phenylalanine-derived melanin from Yarrowia lipolytica mediates the synthesis of silver and gold nanostructures.

    Science.gov (United States)

    Apte, Mugdha; Girme, Gauri; Bankar, Ashok; Ravikumar, Ameeta; Zinjarde, Smita

    2013-01-30

    Nanobiotechnology applies the capabilities of biological systems in generating a variety of nano-sized structures. Plants, algae, fungi and bacteria are some systems mediating such reactions. In fungi, the synthesis of melanin is an important strategy for cell-survival under metal-stressed conditions. Yarrowia lipolytica, the biotechnologically significant yeast also produces melanin that sequesters heavy metal ions. The content of this cell-associated melanin is often low and precursors such as L-tyrosine or 3, 4-dihydroxy-L-phenylalanine (L-DOPA) can enhance its production. The induced melanin has not been exploited for the synthesis of nanostructures. In this investigation, we have employed L-DOPA-melanin for the facile synthesis of silver and gold nanostructures. The former have been used for the development of anti-fungal paints. Yarrowia lipolytica NCIM 3590 cells were incubated with L-DOPA for 18 h and the resultant dark pigment was subjected to physical and chemical analysis. This biopolymer was used as a reducing and stabilizing agent for the synthesis of silver and gold nanostructures. These nanoparticles were characterized by UV-Visible spectra, X-ray diffraction (XRD) studies, and electron microscopy. Silver nanoparticles were evaluated for anti-fungal activity. The pigment isolated from Y. lipolytica was identified as melanin. The induced pigment reduced silver nitrate and chloroauric acid to silver and gold nanostructures, respectively. The silver nanoparticles were smaller in size (7 nm) and displayed excellent anti-fungal properties towards an Aspergillus sp. isolated from a wall surface. An application of these nanoparticles as effective paint-additives has been demonstrated. The yeast mediated enhanced production of the metal-ion-reducing pigment, melanin. A simple and rapid method for the extracellular synthesis of nanoparticles with paint-additive-application was developed.

  8. Diagnostic utility of melanin production by fungi: Study on tissue sections and culture smears with Masson-Fontana stain

    Directory of Open Access Journals (Sweden)

    Challa Sundaram

    2014-01-01

    Full Text Available Background: Dematiaceous fungi appear brown in tissue section due to melanin in their cell walls. When the brown color is not seen on routine H and E and culture is not available, differentiation of dematiaceous fungi from other fungi is difficult on morphology alone. Aims and Objective: To study if melanin production by dematiaceous fungi can help differentiate them from other types of fungi. Materials and Methods: Fifty tissue sections of various fungal infections and 13 smears from cultures of different species of fungi were stained with Masson Fontana stain to assess melanin production. The tissue sections included biopsies from 26 culture-proven fungi and 24 biopsies of filamentous fungi diagnosed on morphology alone with no culture confirmation. Results: All culture-proven dematiaceous fungi and Zygomycetes showed strong positivity in sections and culture smears. Aspergillus sp showed variable positivity and intensity. Cryptococcus neoformans showed strong positivity in tissue sections and culture smears. Tissue sections of septate filamentous fungi (9/15, Zygomycetes (4/5, and fungi with both hyphal and yeast morphology (4/4 showed positivity for melanin. The septate filamentous fungi negative for melanin were from biopsy samples of fungal sinusitis including both allergic and invasive fungal sinusitis and colonizing fungal balls. Conclusion: Melanin is produced by both dematiaceous and non-dematiaceous fungi. Masson-Fontana stain cannot reliably differentiate dematiaceous fungi from other filamentous fungi like Aspergillus sp; however, absence of melanin in the hyphae may be used to rule out dematiaceous fungi from other filamentous fungi. In the differential diagnosis of yeast fungi, Cryptococcus sp can be differentiated from Candida sp by Masson-Fontana stain in tissue sections.

  9. Adaptive melanin response of the soil fungus Aspergillus niger to UV radiation stress at "Evolution Canyon", Mount Carmel, Israel.

    Directory of Open Access Journals (Sweden)

    Natarajan Singaravelan

    Full Text Available BACKGROUND: Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s that evolve in direct response to selection, enhancing the organism's fitness. "Evolution Canyon" (EC in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric "African" slope (AS receives 200%-800% higher solar radiation than the north-facing, temperate, shady and mesic "European" slope (ES, 200 meters apart. Thus, solar ultraviolet radiation (UVR is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. METHODOLOGY/PRINCIPAL FINDINGS: We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin

  10. Inhibitory Effects of Adlay Extract on Melanin Production and Cellular Oxygen Stress in B16F10 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Huey-Chun Huang

    2014-09-01

    Full Text Available The aim of this study was to determine the effects of adlay extract on melanin production and the antioxidant characteristics of the extract. The seeds were extracted by the supercritical fluid CO2 extraction (SFE method. The effect of adlay extract on melanin production was evaluated using mushroom tyrosinase activity assay, intracellular tyrosinase activity, antioxidant properties and melanin content. Those assays were performed spectrophotometrically. In addition, the expression of melanogenesis-related proteins was determined by western blotting. The results revealed that the adlay extract suppressed intracellular tyrosinase activity and decreased the amount of melanin in B16F10 cells. The adlay extract decreased the expression of microphthalmia-associated transcription factor (MITF, tyrosinase, tyrosinase related protein-1 (TRP-1 and tyrosinase related protein-2 (TRP-2. The extract also exhibited antioxidant characteristics such as free radical scavenging capacity and reducing power. It effectively decreased intracellular reactive oxygen species (ROS levels in B16F10 cells. We concluded that the adlay extract inhibits melanin production by down-regulation of MITF, tyrosinase, TRP-1 and TRP-2. The antioxidant properties of the extract may also contribute to the inhibition of melanogenesis. The adlay extract can therefore be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products.

  11. Population-related genetic aspects of the low doses radiological risk and melanin influence on genetic radiosensitivity

    International Nuclear Information System (INIS)

    Mosse, I.B.; Plotnikova, S.I.; Kostrova, L.N.; Subbot, S.T.; Maksymenia, I.P.; Dubovic, B.V.

    1997-01-01

    From the genetic point of view, radiation sensitivity is a quantitative character, and the distribution of individuals in the population with different radiation sensitivities is characterized by a binomial curve. Thus rise in irradiation dose first results in a very slow increase in the number of sensitive genotypes, and then in a sharp rise. Since quantitative characters are dependent on several polymeric genes, and their manifestation is strongly affected by external conditions, radiation sensitivity of the organism depends on many hereditary and environmental factors. One of them is the presence of melanin pigment in cells. In particular, we have shown that the introduction of exogenous melanin into the organisms of mice reduces (2-4 times) the frequency of mutations, induced not only by acute, but also by chronic irradiation. It was also established, that mutational load, accumulated in drosophila populations, irradiated within 125 generations, has been decreased under melanin influence almost to the control level. Antimutagenic action of melanin is also manifested on cultured human cells. So, it was shown by the example of melanin, that it is possible to increase the radiation resistance of individuals, and in the first place of the population highly sensitive fraction. (author)

  12. /sup 125/I-iodinated benzazepines bind to melanin: implications for the noninvasive localization of pigmented melanomas

    Energy Technology Data Exchange (ETDEWEB)

    Agui, T.; Bryant, G.; Kebabian, J.W.; Larson, S.; Saavedra, J.M.; Shigematsu, K.; Yamamoto, T.; Yokoyama, K.

    1987-01-01

    Both the 5-R and the 5-S enantiomers of (/sup 125/I)2,3,4,5-tetrahydro-8-iodo-3-methyl-5-phenyl-1H-3-benzazepin-7-ol bind to melanin. The interaction between the 5-R enantiomer and melanin permits visualization of melanomas in mice with a noninvasive imaging procedure. Two lines of evidence suggest that the interaction between iodinated ligands and melanin is not related to the D-1 dopamine receptor, a known target for the 5-R enantiomer: first, melanin binds both enantiomers of the /sup 125/I-iodinated benzazepine while the D-1 receptor binds only the 5-R enantiomer; second, the melanin binding site displays only a 5-fold difference in affinity towards the R-and S-enantiomers of SCH 23390 while the D-1 receptor displays a 100-fold difference in affinity towards these two molecules. Because both enantiomers of the iodinated benzazepine bind to a human pigmented melanoma, we propose that such compounds may be of use in the diagnosis of pigmented melanoma: in addition, we discuss the possible application of these molecules as a supplement to existing technology for the localization of pigmented melanomas.

  13. VdPKS1 is required for melanin formation and virulence in a cotton wilt pathogen Verticillium dahliae.

    Science.gov (United States)

    Zhang, Ting; Zhang, Bosen; Hua, Chenlei; Meng, Pei; Wang, Sheng; Chen, Zhirong; Du, Yejuan; Gao, Feng; Huang, Jiafeng

    2017-08-01

    Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form of melanized microsclerotia. To investigate the melanin synthesis in V. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in V. dahliae. The VdPKS1 gene-disruption mutant (vdpks1) formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of V. dahliae.

  14. Effects of melanin on high- and low- linear energy transfer (LET) radiation response of human epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Grossi, G.F.; Durante, M.; Gialanella, G. [Dipartimento di Scienze Fisiche, Univ. di Napoli and Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (Italy); Pugliese, M. [Servizio di Radioprotezione, Univ. di Napoli (Italy); Mosse, I. [Institute of Genetics and Cytology of Belarus Academy of Sciences, Minsk (Belarus)

    1998-04-01

    The search for effective radioprotectors is of major concern in the medical, military, environmental, and space sciences. Conventional radioprotectors are generally effective only during a single irradiation and display their radioprotective properties only at high, toxic concentrations. In addition, they reduce somatic radiation effects but are poorly efficient in protecting from hereditary stochastic radiation effects. In this respect, the pigment melanin merits attention. Experiments referring to potential melanin effects on the ionising radiation response have been carried out with different biological systems, both in vivo and in vitro. In this paper, we present results on the response to high- and low-linear energy transfer (LET) radiation of a human mammary epithelial cell line, H184B5 F5-1 M/10, supplemented by melanin. The incorporation of auto-oxidative (l-dopa) melanin was linear for concentrations from 3 to 10 {mu}g/ml in the growth medium. Concentrations of up to 250 {mu}g/ml did not significantly impair the cells proliferative ability. No significant protective effect of melanin on the survival of cultured cells after exposure to alpha-particles (130 keV/{mu}m) or x-rays was observed. (orig.) With 2 figs., 3 tabs., 35 refs.

  15. S-(−-10,11-Dihydroxyfarnesoic Acid Methyl Ester Inhibits Melanin Synthesis in Murine Melanocyte Cells

    Directory of Open Access Journals (Sweden)

    Seung-Hwa Baek

    2014-07-01

    Full Text Available The development of antimelanogenic agents is important for the prevention of serious aesthetic problems such as melasmas, freckles, age spots, and chloasmas. In the course of screening for melanin synthesis inhibitors, we found that the culture broth from an insect morphopathogenic fungus, Beauveria bassiana CS1029, exhibits potent antimelanogenic activity. We isolated and purified an active metabolite and identified it as S-(−-10,11-dihydroxyfarnesoic acid methyl ester (dhFAME, an insect juvenile hormone. To address whether dhFAME inhibits melanin synthesis, we first measured the size of the melanin biosynthesis inhibition zone caused by dhFAME. dhFAME also showed inhibitory activity against mushroom tyrosinase in Melan-a cells. Intracellular, dose-dependent tyrosinase inhibition activity was also confirmed by zymography. In addition, we showed that dhFAME strongly inhibits melanin synthesis in Melan-a cells. Furthermore, we compared levels of TYR, TRP-1, TRP-2, MITF, and MC1R mRNA expression by reverse-transcription polymerase chain reaction and showed that treatment of Melan-a cells with 35 μM dhFAME led to an 11-fold decrease in TYR expression, a 6-fold decrease in TRP-2 expression, and a 5-fold decrease in MITF expression. Together, these results indicate that dhFAME is a potent inhibitor of melanin synthesis that can potentially be used for cosmetic biomaterial(s.

  16. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Pawlowski, A.; Persad, S.D.; Menon, I.A.; Haberman, H.F.

    1988-01-01

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells.

  17. Melanins in Fossil Animals: Is It Possible to Infer Life History Traits from the Coloration of Extinct Species?

    Science.gov (United States)

    Negro, Juan J; Finlayson, Clive; Galván, Ismael

    2018-01-23

    Paleo-colour scientists have recently made the transition from describing melanin-based colouration in fossil specimens to inferring life-history traits of the species involved. Two such cases correspond to counter-shaded dinosaurs: dark-coloured due to melanins dorsally, and light-coloured ventrally. We believe that colour reconstruction of fossils based on the shape of preserved microstructures-the majority of paleo-colour studies involve melanin granules-is not without risks. In addition, animals with contrasting dorso-ventral colouration may be under different selection pressures beyond the need for camouflage, including, for instance, visual communication or ultraviolet (UV) protection. Melanin production is costly, and animals may invest less in areas of the integument where pigments are less needed. In addition, melanocytes exposed to UV radiation produce more melanin than unexposed melanocytes. Pigment economization may thus explain the colour pattern of some counter-shaded animals, including extinct species. Even in well-studied extant species, their diversity of hues and patterns is far from being understood; inferring colours and their functions in species only known from one or few specimens from the fossil record should be exerted with special prudence.

  18. Melanins in Fossil Animals: Is It Possible to Infer Life History Traits from the Coloration of Extinct Species?

    Directory of Open Access Journals (Sweden)

    Juan J. Negro

    2018-01-01

    Full Text Available Paleo-colour scientists have recently made the transition from describing melanin-based colouration in fossil specimens to inferring life-history traits of the species involved. Two such cases correspond to counter-shaded dinosaurs: dark-coloured due to melanins dorsally, and light-coloured ventrally. We believe that colour reconstruction of fossils based on the shape of preserved microstructures—the majority of paleo-colour studies involve melanin granules—is not without risks. In addition, animals with contrasting dorso-ventral colouration may be under different selection pressures beyond the need for camouflage, including, for instance, visual communication or ultraviolet (UV protection. Melanin production is costly, and animals may invest less in areas of the integument where pigments are less needed. In addition, melanocytes exposed to UV radiation produce more melanin than unexposed melanocytes. Pigment economization may thus explain the colour pattern of some counter-shaded animals, including extinct species. Even in well-studied extant species, their diversity of hues and patterns is far from being understood; inferring colours and their functions in species only known from one or few specimens from the fossil record should be exerted with special prudence.

  19. pH-Induced aggregated melanin nanoparticles for photoacoustic signal amplification

    Science.gov (United States)

    Ju, Kuk-Youn; Kang, Jeeun; Pyo, Jung; Lim, Joohyun; Chang, Jin Ho; Lee, Jin-Kyu

    2016-07-01

    We present a new melanin-like nanoparticle (MelNP) and its performance evaluation results. This particle is proposed as an exogenous contrast agent for photoacoustic (PA) imaging. Conventional PA contrast agents are based on non-biological materials. In contrast, the MelNPs are organic nanoparticles inspired by natural melanin. Melanin is an endogenous chromophore that has the ability to produce a PA signal in vivo. The developed MelNPs are capable of aggregating with one another under mildly acidic conditions after introducing hydrolysis-susceptible citraconic amide on the surface of bare MelNPs. We ascertained that the physical aggregation of the MelNPs resulted in an increased PA signal strength in the near-infrared window of biological tissue (i.e., 700 nm) without absorption tuning. This phenomenon is likely because of the overlapping thermal fields of the developed MelNPs. The PA signal produced from the developed MelNPs, after exposure to mildly acidic conditions (i.e., pH 6), is 8.1 times stronger than under neutral conditions. This unique characteristic found in this study can be utilized in a practical strategy for highly sensitive in vivo cancer target imaging in response to its acidic microenvironment. This approach to amplify the PA response of MelNPs in clusters could accelerate the use of MelNPs as an alternative to non-biological nanoprobes, so that MelNPs may be applicable in PA imaging and functional PA imaging such as stimuli sensitive, multimodal, and theranostic imaging.We present a new melanin-like nanoparticle (MelNP) and its performance evaluation results. This particle is proposed as an exogenous contrast agent for photoacoustic (PA) imaging. Conventional PA contrast agents are based on non-biological materials. In contrast, the MelNPs are organic nanoparticles inspired by natural melanin. Melanin is an endogenous chromophore that has the ability to produce a PA signal in vivo. The developed MelNPs are capable of aggregating with one

  20. Transcription factor Amr1 induces melanin biosynthesis and suppresses virulence in Alternaria brassicicola.

    Directory of Open Access Journals (Sweden)

    Yangrae Cho

    Full Text Available Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC were nonpathogenic and another gene (AbVf8 caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of Δamr1 and characterized their phenotypes. The Δamr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  1. Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yangrae; Srivastava, Akhil; Ohm, Robin A.; Lawrence, Christopher B.; Wang, Koon-Hui; Grigoriev, Igor V.; Marahatta, Sharadchandra P.

    2012-05-01

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC) were nonpathogenic and another gene (AbVf8) caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of ?amr1 and characterized their phenotypes. The ?amr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  2. The comparison of the melanin content and UV exposure affecting aging process: seven countries in Asia.

    Science.gov (United States)

    Bae, Sung Hae; Park, Jung Jun; Song, Eun Jeung; Lee, Jung Ah; Byun, Kyung Soo; Kim, Nam Soo; Moon, Tae Kee

    2016-12-01

    The skin brightness is determined according to the amount and type of melanin. People with darker skin have a greater amount of melanin that makes their skin less susceptible to UV damages. They live in lower latitude and receive a greater amount of the intensity of the UV radiation. We wanted to know how the latitude and skin brightness affect skin aging. Three thousand volunteers from seven countries (Korea, China, India, Thailand, Vietnam, Indonesia, and Malaysia), aged 20-59 years, participated in this study. We measured skin brightness, Ra (wrinkles parameter), and R2 (elasticity parameter) under controlled environmental conditions. The skin brightness of the face was measured using the Janus ® which is a facial analysis system. Cutometer ® the elasticity was measured by on the cheeks, and PRIMOS lite ® was used to evaluate wrinkles on crow's feet. Latitude and skin brightness showed a positive correlation (0.346). Also, the correlations of Ra and R2 with skin brightness were significantly negative (-0.181) and positive (0.105), respectively. Results of comparison of Ra and R2 with age among the countries showed no significant difference among the 20s, but there was a significant difference among the 50s between countries with high latitude and low latitude. The long-term exposure of UV radiation, the natural environmental factor, seems to have more decisive effect on the skin aging process than the photoprotective effect of melanin of epidermal skin. This study helps to understand differences of the skin properties among countries in Asia. © 2016 Wiley Periodicals, Inc.

  3. Duration of reappearance of gingival melanin pigmentation after surgical removal - A clinical study

    Directory of Open Access Journals (Sweden)

    Kaur Harjit

    2010-01-01

    Full Text Available Background: In dentistry, esthetics has a special place. Although gingival melanin pigmentation does not present a medical problem, clinicians are often faced with a challenge of achieving gingival esthetics. Materials and Methods: A method of de-epithelialization of the pigmented gingiva using Kirkland′s gingivectomy knife is described. Twenty patients who were conscious about their gingival melanin pigmentation were selected. The gingiva of the whole of the arch was abraded until the entire visible pigmentation was removed. Clinical observations for intensity of pigmentation were recorded at baseline and then after surgery at monthly intervals over a period of 9 months according to Dummett-Gupta Oral Pigmentation Index scoring criteria proposed by Dummett C. O. in 1964. Results: The mean gingival melanin pigmentation score came down to 0.407 after 9 months as compared to preoperative score, which was 2.24. No repigmentation occurred in fair-complexioned persons. In persons with wheatish complexion, repigmentation was seen in 85.71% of the cases, but scores came down to 0.38 postoperatively as compared to 2.27 preoperatively. In dark complexioned persons, repigmentation occurred in all cases, but the mean scores were 0.93 as compared to 2.40 preoperatively. The difference between preoperative and postoperative mean scores for each segment was put to statistical analysis by applying paired t test and was found to be significant. Conclusion: As this method has shown statistically significant results, it can be used in patients who are conscious of pigmented gingiva and want an esthetically satisfactory color.

  4. Microneedling dilates the follicular infundibulum and increases transfollicular absorption of liposomal sepia melanin

    Directory of Open Access Journals (Sweden)

    Serrano G

    2015-06-01

    Full Text Available Gabriel Serrano,1 Patricia Almudéver,2 Juan M Serrano,3 Julio Cortijo,2 Carmen Faus,1 Magda Reyes,1 Inmaculada Expósito,3 Ana Torrens,3 Fernando Millán1 1Clínica Dermatológica Serrano, 2Department of Pharmacology, University of Valencia, 3Research and Development Department, Sesderma Laboratories, Valencia, Spain Abstract: Encapsulation of chemicals in liposomes and microneedling are currently used techniques to enhance the penetration of several substances through skin and hair. In this study, we apply a liposomal melanin–fluorescein compound to an ex vivo model of human skin, using a new electrical microneedling device (Nanopore turbo roller. The product was applied by hand massage (A or with the assistance of the electrical roller for 2 minutes (B. An additional test was performed free of product and with only the E-roller (C. Histological changes and product absorption were evaluated by optical and fluorescent microscopy 60 and 90 minutes after the treatment. Site B showed larger deposits of melanin–fluorescein at superficial and deep levels of hair structures in comparison to site A. Light, epidermal deposits of the melanin–fluorescein complex were also observed. Sites B and C showed a significant widening (47% of the follicular infundibulum which could explain the increased penetration of the formulation. Microneedling also removed the scales and sebum residues in the neighborhood of the infundibulum. Targeting hair follicles with melanin may be useful to dye poorly pigmented hairs, improving laser hair removal. The procedure accelerates the delivery of melanin into hair structures allowing an even absorption, larger pigment deposits, and deeper penetration of the formulation into the hair. Keywords: liposomes, melanin, microneedling, follicular infundibulum, hair removal

  5. Complexity and integration in sexual ornamentation: an example with carotenoid and melanin plumage pigmentation.

    Science.gov (United States)

    Badyaev, A V; Young, R L

    2004-11-01

    Sexual ornaments often consist of several components produced by distinct developmental processes. The complexity of sexual ornaments might be favoured by mate choice of individual components in different environments which ultimately results in weak interrelationships (integration) among the developmental processes that produce these components. At the same time, sexual selection for greater exaggeration of individual components favours their stronger co-dependence on organismal resources. This should ultimately produce stronger condition-mediated integration among ornaments' components in individuals with the most exaggerated ornamentation. Here we distinguish between these two sources of integration by examining the relationship between integration and elaboration of sexual ornamentation in three bird species: two with carotenoid-based sexual ornamentation (the house finch, Carpodacus mexicanus and common redpoll, Carduelis flammea) and a species with melanin-based sexual ornamentation (house sparrow, Passer domesticus). We found that integration of components varied with elaboration of carotenoid-based ornamentation but not of melanin ornamentation. In the house finches, integration was the highest in individuals with small ornaments and decreased with ornament elaboration whereas the pattern was the opposite in common redpolls. These results suggest that in these species integration and complexity of carotenoid-based ornamental components are due to shared condition-dependence of distinct developmental pathways, whereas integration and complexity of the melanin ornamentation is due to organismal integration of developmental pathways and is largely condition- and environment-invariant. Thus, functionally, ornamentation of the house sparrows can be considered a single trait, whereas complexity of the house finch and redpoll ornamentation varies with ornament elaboration and individual condition.

  6. Enzymatic synthesis of arbutin undecylenic acid ester and its inhibitory effect on melanin synthesis.

    Science.gov (United States)

    Tokiwa, Yutaka; Kitagawa, Masaru; Raku, Takao; Yanagitani, Shusaku; Yoshino, Kenji

    2007-06-01

    Transesterification of arbutin and undecylenic acid vinyl ester was catalyzed by alkaline protease, Bioprase, in dimethylformamide to get arbutin derivative having undecylenic acid at 6-position of glucose moiety, 6-O-undecylenoyl p-hydroxyphenyl beta-D-glucopyranoside. The reaction rate increased with increase of arbutin concentration, and when its concentration was 0.9 M, the conversion rate was more than 90% under addition of 2 M undecylenic acid vinyl ester. The obtained arbutin ester significantly suppressed melanin production in murine B16 melanoma cells.

  7. Evolution of physicochemical properties of melanin concentrating hormone receptor 1 (MCHr1) antagonists.

    Science.gov (United States)

    Johansson, Anders

    2016-10-01

    One pharmacological principle for the treatment of obesity is blockade of the melanin concentrating hormone receptor 1 (MCHr1), which in rodents has been shown to be strongly associated with food intake and energy expenditure. However, discovery of safe and efficacious MCHr1 antagonists has proved to be complex. So far, six compounds have been progressed into clinical trials, but clinical validation of the concept is still lacking. An account of discovery of the three most recent clinical candidates targeting the MCHr1 receptor is given, with an emphasis on their physicochemical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. [A comparative characterization of fungal melanin and the humin-like substances synthesized by Cerrena maxima 0275].

    Science.gov (United States)

    Koroleva, O V; Kulikova, N A; Alekseeva, T N; Stepanova, E V; Davidchik, V N; Beliaeva, E Iu; Tsvetkova, E A

    2007-01-01

    Comparative studies of fungal melanin and two preparations of the high-molecular-weight humin-like substances formed during a solid-phase cultivation of the basidiomycete Cerrena maxima 0275 for 45 and 70 days were performed. The fungal melanin from Aspergillus niger and the humin-like substances synthesized by the basidiomycete C. maxima 0275 are similar in their physicochemical properties (elemental composition and behavior in acids and alkalis) and auxin-like activities. However, these biopolymers differ, essentially, at the structural level. According to IR spectroscopy data, the obtained humin-like substances display a higher similarity to natural humic acids and are more diverse in their functional groups compared with fungal melanins. Presumably, this is connected with the fact that laccase is involved in formation of humin-like substances; moreover, this enzyme is involved not only in the synthesis of these polymers, but also in their modification and degradation.

  9. EPR examination of free radical properties of DOPA-melanin complexes with ciprofloxacin, lomefloxacin, norfloxacin and sparfloxacin

    Science.gov (United States)

    Beberok, Artur; Buszman, Ewa; Zdybel, Magdalena; Pilawa, Barbara; Wrześniok, Dorota

    2010-09-01

    Paramagnetic complexes of DOPA-melanin with ciprofloxacin, lomefloxacin, norfloxacin and sparfloxacin were studied by EPR spectroscopy. The aim of this work was to determine free radical concentration and properties of these complexes. Free radical concentrations in the studied complexes were ∼1019-1020 spin/g. Relatively lower and similar (5.1-6.6 × 1019 spin/g) free radical concentrations characterized DOPA-melanin complexes with ciprofloxacin, and lomefloxacin. Higher concentrations (0.8-1.2 × 1020 spin/g) were obtained for complexes of norfloxacin and sparfloxacin. Effect of the drug concentration on free radicals in melanin was observed. Strong dipolar spin-spin interactions and slow spin-lattice relaxation processes exist in all of the samples.

  10. Melanin pigmented periradicular lesions of extracted teeth: a report of 3 cases and review of the literature.

    Science.gov (United States)

    Omoregie, F O; Odukoya, O; Ojo, M A; Saheeb, B D

    2011-09-01

    This article reports 3 cases of melanin pigmented lesions among 75 histologically diagnosed periradicular lesions of extracted teeth. Case 1 was a 25-year old male who presented with one week history of toothache involving a tender carious left mandibular second molar tooth (37), with periapical radiolucency and diagnosed clinically as acute apical periodontitis. The lesion was diagnosed histologically (using Haematoxylin and Eosin) as periapical granuloma, while histochemical examination (using Masson-Fontana technique) showed the presence of round/oval shaped melanin pigmented macrophages (melanophage) in the lesion. Case 2 was a 54-year old male with one week history of toothache associated with tender carious right maxillary first molar tooth (16) with periapical radiolucency. A clinical diagnosis of acute apical periodontitis was made, but histological and histochemical examination showed a melanin pigmented periapical granuloma with spindle shaped melanophage. Case 3 was a 28-year old female who presented with 4 days history of toothache, involving the tender left mandibular first molar tooth (36). The lesion had periapical radiolucency and a clinical diagnosis of acute apical periodontitis. On examination histologically and histochemically, the lesion was diagnosed as an intraosseous melanocytic naevi with dark-brown nests of round naevus cells. In conclusion, this article shows the rarity of melanin pigmented periradicular lesions in the jaws. The cases reported suggest that the trigger for formation of melanin-pigmented cells in the periradicular lesions may be related to the acute phase of the lesions. Further study is recommended to determine if the remnants of the migratory neural crest cells are the precursors of melanin-pigmented cells in the periradicular region.

  11. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with photoacoustic ophthalmoscopy and autofluorescence imaging

    Science.gov (United States)

    Zhang, Xiangyang; Zhang, Hao F.; Puliafito, Carmen A.; Jiao, Shuliang

    2011-08-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective versus exacerbate) in the RPE in the aging process. We have successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  12. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Directory of Open Access Journals (Sweden)

    Miguel J Beltrán-García

    Full Text Available In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg. Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg, a highly reactive oxygen specie (ROS that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg. A pigmented-strain generated more O2 (1Δg than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2 but we cannot distinguish the source. Our results suggest that O2 (1Δg photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.

  13. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Science.gov (United States)

    Beltrán-García, Miguel J; Prado, Fernanda M; Oliveira, Marilene S; Ortiz-Mendoza, David; Scalfo, Alexsandra C; Pessoa, Adalberto; Medeiros, Marisa H G; White, James F; Di Mascio, Paolo

    2014-01-01

    In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.

  14. Photoprotective role of epidermal melanin granules against ultraviolet damage and DNA repair in guinea pig skin

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T.; Kodama, K.; Matsumoto, J.; Takayama, S.

    1984-11-01

    We previously developed a quantitative autoradiographic technique with special forceps for measuring unscheduled DNA synthesis (UDS) in mouse skin after treatment with ultraviolet light in vivo. By this method, we investigated the relationship between the protective role of melanin and UV-induced DNA repair in black-and-white guinea pigs. Flat areas containing a sharp border between pigmented and unpigmented skin were selected. The skin of the selected areas was shaved and irradiated with short-wave UV (254 nm) or UV-AB (270 to 440 nm, emission peak at 312 nm) at various doses. Immediately after irradiation, the skin was clamped off with forceps, and an isotonic aqueous solution of (methyl-/sup 3/H)thymidine was injected s.c. into the clamped off portion. UDS was clearly demonstrated as silver grains in this portion of the skin after irradiation with 254 nm UV or UV-AB. Errors due to individual differences were avoided by comparing the intensities of UDS in basal cells from pigmented skin and unpigmented skin of the same animals. Unexpectedly, in groups of animals treated with 254 nm UV or UV-AB, no difference in UDS in pigmented and unpigmented skin was seen at any UV dose. These results suggested that epidermal melanin granules do not significantly protect DNA of basal cells against 254 nm UV or UV-AB irradiation. Results of a study on the effect of the wavelength of irradiation on the UDS response of albino guinea pigs are also reported.

  15. Melanin Transfer in Human 3D Skin Equivalents Generated Exclusively from Induced Pluripotent Stem Cells.

    Directory of Open Access Journals (Sweden)

    Karl Gledhill

    Full Text Available The current utility of 3D skin equivalents is limited by the fact that existing models fail to recapitulate the cellular complexity of human skin. They often contain few cell types and no appendages, in part because many cells found in the skin are difficult to isolate from intact tissue and cannot be expanded in culture. Induced pluripotent stem cells (iPSCs present an avenue by which we can overcome this issue due to their ability to be differentiated into multiple cell types in the body and their unlimited growth potential. We previously reported generation of the first human 3D skin equivalents from iPSC-derived fibroblasts and iPSC-derived keratinocytes, demonstrating that iPSCs can provide a foundation for modeling a complex human organ such as skin. Here, we have increased the complexity of this model by including additional iPSC-derived melanocytes. Epidermal melanocytes, which are largely responsible for skin pigmentation, represent the second most numerous cell type found in normal human epidermis and as such represent a logical next addition. We report efficient melanin production from iPSC-derived melanocytes and transfer within an entirely iPSC-derived epidermal-melanin unit and generation of the first functional human 3D skin equivalents made from iPSC-derived fibroblasts, keratinocytes and melanocytes.

  16. 4-(Phenylsulfanylbutan-2-One Suppresses Melanin Synthesis and Melanosome Maturation In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Shing-Yi Sean Wu

    2015-08-01

    Full Text Available In this study, we screened compounds with skin whitening properties and favorable safety profiles from a series of marine related natural products, which were isolated from Formosan soft coral Cladiella australis. Our results indicated that 4-(phenylsulfanylbutan-2-one could successfully inhibit pigment generation processes in mushroom tyrosinase platform assay, probably through the suppression of tyrosinase activity to be a non-competitive inhibitor of tyrosinase. In cell-based viability examinations, it demonstrated low cytotoxicity on melanoma cells and other normal human cells. It exhibited stronger inhibitions of melanin production and tyrosinase activity than arbutin or 1-phenyl-2-thiourea (PTU. Also, we discovered that 4-(phenylsulfanylbutan-2-one reduces the protein expressions of melanin synthesis-related proteins, including the microphthalmia-associated transcription factor (MITF, tyrosinase-related protein-1 (Trp-1, dopachrome tautomerase (DCT, Trp-2, and glycoprotein 100 (GP100. In an in vivo zebrafish model, it presented a remarkable suppression in melanogenesis after 48 h. In summary, our in vitro and in vivo biological assays showed that 4-(phenylsulfanylbutan-2-one possesses anti-melanogenic properties that are significant in medical cosmetology.

  17. A Compatible Sensitivity Enhancement Strategy for Electrochemiluminescence Immunosensors Based on the Biomimetic Melanin-Like Deposition.

    Science.gov (United States)

    Ma, Hongmin; Zhao, Yanhua; Liu, Yuanyuan; Zhang, Yong; Wu, Dan; Li, He; Wei, Qin

    2017-12-19

    In this work, a compatible strategy was demonstrated for the enhancement of detection sensitivity of sandwich-type electrochemiluminescence (ECL) immunosensors. The enhanced signal response was based on the combination of biomimetic melanin-like deposition with the effective ECL quenching ability of quinone-rich biopolymers. Gold nanoparticle-loaded horseradish peroxidase (HRP) was used as a catalytic label for the secondary antibodies. The intrinsic catalytic property of HRP toward hydrogen peroxide (H 2 O 2 ) generates reactive oxygen species, which highly promote the autopolymerization of catecholamines. The resulting fast deposition of quinone-rich biopolymers approaching the luminophor-incorporated sensing platform achieves an obvious ECL quenching. A broad-spectrum tumor marker alpha fetoprotein (AFP) was selected as a model analyte to demonstrate the feasibility of the proposed strategy. Under optimal conditions, a very low detection limit of 0.056 pg mL -1 was obtained. Two orders of magnitude enhancement was achieved in contrast to the signal response without the step of catalytic biopolymer deposition. The combination of compatible HRP labeling with unique melanin-like deposition has potential as a universal strategy in other ECL bioassays.

  18. Melanin-Based Contrast Agents for Biomedical Optoacoustic Imaging and Theranostic Applications.

    Science.gov (United States)

    Longo, Dario Livio; Stefania, Rachele; Aime, Silvio; Oraevsky, Alexander

    2017-08-07

    Optoacoustic imaging emerged in early 1990s as a new biomedical imaging technology that generates images by illuminating tissues with short laser pulses and detecting resulting ultrasound waves. This technique takes advantage of the spectroscopic approach to molecular imaging, and delivers high-resolution images in the depth of tissue. Resolution of the optoacoustic imaging is scalable, so that biomedical systems from cellular organelles to large organs can be visualized and, more importantly, characterized based on their optical absorption coefficient, which is proportional to the concentration of absorbing chromophores. Optoacoustic imaging was shown to be useful in both preclinical research using small animal models and in clinical applications. Applications in the field of molecular imaging offer abundant opportunities for the development of highly specific and effective contrast agents for quantitative optoacoustic imaging. Recent efforts are being made in the direction of nontoxic biodegradable contrast agents (such as nanoparticles made of melanin) that are potentially applicable in clinical optoacoustic imaging. In order to increase the efficiency and specificity of contrast agents and probes, they need to be made smart and capable of controlled accumulation in the target cells. This review was written in recognition of the potential breakthroughs in medical optoacoustic imaging that can be enabled by efficient and nontoxic melanin-based optoacoustic contrast agents.

  19. A drug release system induced by near infrared laser using alginate microparticles containing melanin.

    Science.gov (United States)

    Kim, Min Ah; Yoon, Soon Do; Lee, Chang-Moon

    2017-10-01

    The photothermal effect is used in a new drug release system to control drug delivery in a specific region. Melanin absorbs near-infrared (NIR) light with a high photothermal conversion efficiency, and as a result, an NIR laser can be used to induced drug release from alginate microparticles containing melanin (ALG-Mel microparticles). The temperature of the ALG-Mel microparticle solution at a concentration of 5mg/mL increased to 38.1°C from 26.0°C after irradiation with 808nm NIR at 1.5W/cm 2 for 5min, and this increase in temperature was found to be independent of the ALG-Mel microparticle concentration. After the NIR laser irradiation, 5-fluorouracil (5-FU) was released from the ALG-Mel microparticles to 87.4±0.5% of the total loaded drug for 24h. Without NIR laser irradiation, 5-FU was released from the ALG-Mel microparticles to 60.8±1.5% of the total loaded drug for 24h. These results indicate that NIR laser irradiation can be used with ALG-Mel microparticles as a drug delivery system for release within a target region. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Brassica rapa hairy root extracts promote skin depigmentation by modulating melanin production and distribution.

    Science.gov (United States)

    Sena, Luigi Michele; Zappelli, Claudia; Apone, Fabio; Barbulova, Ani; Tito, Annalisa; Leone, Antonella; Oliviero, Teresa; Ferracane, Rosalia; Fogliano, Vincenzo; Colucci, Gabriella

    2017-07-03

    Skin whitening products, used for ages by Asian people for cultural and esthetic purposes, are very popular nowadays in Western countries as well, where the need to inhibit skin spots after sun exposure has become not only a cosmetic but also a health-related issue. Thus, the development of effective and safe depigmenting agents derived from natural products gets continuous attention by cosmetic brands and consumers. The aim of this study was to determine the effects of two preparations, obtained from the hairy root cultures of the species Brassica rapa, on melanogenesis and the expression of the extracellular matrix proteins involved in a correct pigment distribution. The two preparations, obtained by water-ethanol extraction and by digestion of cell-wall glycoproteins of the root cells, were chemically characterized and tested on skin cell cultures and on human skin explants to investigate on their dermatological activities. Both the extracts were able to decrease melanin synthesis pathway in melanocytes and modulate the expression of genes involved in melanin distribution. One of the extracts was also effective in inducing the expression of laminin-5 and collagen IV, involved into the maintenance of tissue integrity. The two extracts, when tested together on human skin explants, demonstrated a good synergic hypopigmenting activity. Taken together, the results indicate that the extracts from B. rapa root cultures can be employed as cosmetic active ingredients in skin whitening products and as potential therapeutic agents for treating pigmentation disorders. © 2017 Wiley Periodicals, Inc.

  1. Melanin photosensitization and the effect of visible light on epithelial cells.

    Directory of Open Access Journals (Sweden)

    Orlando Chiarelli-Neto

    Full Text Available Protecting human skin from sun exposure is a complex issue that involves unclear aspects of the interaction between light and tissue. A persistent misconception is that visible light is safe for the skin, although several lines of evidence suggest otherwise. Here, we show that visible light can damage melanocytes through melanin photosensitization and singlet oxygen (1O2 generation, thus decreasing cell viability, increasing membrane permeability, and causing both DNA photo-oxidation and necro-apoptotic cell death. UVA (355 nm and visible (532 nm light photosensitize 1O2 with similar yields, and pheomelanin is more efficient than eumelanin at generating 1O2 and resisting photobleaching. Although melanin can protect against the cellular damage induced by UVB, exposure to visible light leads to pre-mutagenic DNA lesions (i.e., Fpg- and Endo III-sensitive modifications; these DNA lesions may be mutagenic and may cause photoaging, as well as other health problems, such as skin cancer.

  2. Effects of melanin-induced free radicals on the isolated rat peritoneal mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ranadive, N.S.; Shirwadkar, S.; Persad, S.; Menon, I.A.

    1986-03-01

    Pheomelanin from human red hair (RHM) produces considerably more cellular damage in Ehrlich ascites carcinoma cells when subjected to radiations of wavelength 320-700 nm than eumelanin from black hair (BHM). Irradiation of RHM generated large amounts of superoxide while BHM did not produce detectable amounts of superoxide. The present investigations describe the effects of irradiation of mast cells in the presence of various natural and synthetic melanins. Irradiation of mast cells in the presence of RHM and red hair melanoprotein released large amounts of histamine while BHM and synthetic melanins prepared from dopa, cysteinyldopa, or a mixture of dopa and cysteinyldopa did not release histamine. The release of histamine at lower concentrations of RHM was not accompanied by the release of /sup 51/Cr from chromium-loaded cells, suggesting that this release was of noncytotoxic nature. On the other hand, the release of histamine at higher concentrations of RHM was due to cell lysis since both histamine and cytoplasmic marker /sup 51/Cr were released to the same extent. The release evoked by large concentration RHM was not inhibited by superoxide dismutase or catalase. This suggests that the cell lysis under these conditions was not due to H/sub 2/O/sub 2/ or O-2. The finding that mast cells release histamine when irradiated in the presence of RHM suggests that the immediate and late-phase reactions seen in sunburn may in part be due to the release of mediators from these cells.

  3. New SPECT tracers: Example of tracers of proteoglycans and melanin; Nouveaux traceurs TEMP: exemple des traceurs des proteoglycanes et de la melanine

    Energy Technology Data Exchange (ETDEWEB)

    Cachin, F.; Mestas, D.; Kelly, A.; Merlin, C.; Veyre, A.; Maublant, J. [CRLCC Jean-Perrin, Service de Medecine Nucleaire, 63 - Clermont-Ferrand (France); Cachin, F.; Chezal, J.M.; Miot-Noirault, E.; Moins, N.; Auzeloux, P.; Vidal, A.; Bonnet-Duquennoy, M.; Boisgard, S.; D' Incan, M.; Madelmont, J.C.; Maublant, J. [Universite d' Auvergne, EA 4231, 63 - Clermont-Ferrand (France); Boisgard, S. [CHRU Gabriel-Montpied, Service d' Orthopedie, 63 - Clermont-Ferrand (France); D' Incan, M. [CHRU Gabriel-Montpied, Service de Dermatologie, 63 - Clermont-Ferrand (France); Redini, F. [Inserm, U957-EA3822, Faculte de Medecine, 44 - Nantes (France); Filaire, M. [Universite d' Auvergne, Lab. d' Anatomie, 63 - Clermont-Ferrand (France)

    2009-02-15

    The majority of research program on new radiopharmaceuticals turn to tracers used for positron emission tomography (PET). Only a few teams work on new non fluorine labeled tracers. However, the coming of SPECT/CT gamma cameras, the arrival of semi-conductors gamma cameras should boost the development of non-PET tracers. We exhibit in this article the experience acquired by our laboratory in the conception and design of two new non fluorine labelled compounds. The {sup 99m}Tc-N.T.P. 15-5 (N.T.P. 15-5 for N-[tri-ethyl-ammonium]-3-propyl-[15]ane-N5) which binds to proteoglycans could be used for the diagnosis and staging of osteoarthritis and chondrosarcoma. The iodo benzamides, specific to the melanin, are nowadays compared to {sup 18}F-fluorodeoxyglucose in a phase III clinical trial for the diagnosis and detection of melanoma metastasis. Our last development focus on N-[2-(diethyl-amino)ethyl]-4 and 2-iodo benzamides respectively B.Z.A. and B.Z.A.2 hetero-aromatic analogues usable for melanoma treatment. (authors)

  4. Topical microemulsion containing Punica granatum extract: its control over skin erythema and melanin in healthy Asian subjects

    Science.gov (United States)

    Parveen, Rashida; Akhtar, Naveed

    2014-01-01

    Introduction Punica granatum is apotent source of polyphenolic compounds with strong free radicals scavenging activity. The skin lightening effects of Punica granatum are assumed due to ellagic acid which acts by chelating copper at the active site of tyrosinase. Aim To explore a topical microemulsion (O/W) of pomegranate (Punica granatum) extract for its control on skin erythema and melanin. Material and methods Microemulsions were formulated using a polysorbate surfactant (Tween 80®) along with cosurfactant (propylene glycol) and were characterized regarding their stability. The placebo microemulsion (without extract) and the active microemulsion (containing Punica extract) were applied in a split face fashion by the volunteers (n = 11) for a period of 12 weeks. Skin erythema and melanin were measured at baseline and after every 15 days to determine any effect produced by these formulations. Results Active formulation showed a significant impact on skin erythema and melanin (p Punica granatum extract for conditions where elevated skin melanin and erythema have significantly prone skin physiology. PMID:25610348

  5. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion

    International Nuclear Information System (INIS)

    Lopes, Luis Mario de Melo

    2002-01-01

    Melanin pigmentation occurs as a result of excessive deposition of melanin, produced by the melanocytes present in the basal layer of the epithelium. This study compares clinical parameters such as inflammation and/or hemorrhage, healing process and re-pigmentation, caused by the Nd:YAG laser ablation and the mechanical abrasion of the melanin, by means of photographic images, taken during the first 30 days after the treatment. The patients comfort was monitored during the first ten days after the treatment using the method of the Visual Analog Scale to measure the pain. Six patients with gingival melanin pigmentation were selected. The left upper gingival quadrant was treated with the Nd:YAG laser using 125 mJ per pulse and 20 Hz, the right upper gingival quadrant received mechanical abrasion and the lower quadrants served for control. Both techniques did not result in inflammation and/or hemorrhage. The healing process was slower with the laser. Using mechanical abrasion, ali patients showed remaining pigmentation or re-pigmentation of varying intensity after a period of 30 days. With the laser 50 % of the patients did not show any re-pigmentation after this period. The pain analysis showed that the pain sensed 24 hours after the treatment with the laser is higher than using mechanical abrasion. (author)

  6. Production of melanin by soil microbial isolate on fruit waste extract: two step optimization of key parameters

    Directory of Open Access Journals (Sweden)

    Korumilli Tarangini

    2014-12-01

    Full Text Available In this study, optimization of production parameters influencing melanin production in an economical fruit waste extract was attempted using a garden soil isolate (Bacillus safensis. Taguchi approach was adopted for screening of critical parameters and further optimization was done using a central composite design of response surface methodology (RSM. At optimum conditions (pH 6.84 and Temp 30.7 °C, a significant yield of ∼6.96 mg/mL was observed. Statistical analysis revealed that the experimental results fitted well to the statistical model with model R2 value 0.982. The optimization of process parameters using RSM reported a 15% increase in the pigment yield than average yield obtained from the studied model. The melanin produced was confirmed by UV–visible spectroscopy, FTIR and XRD analysis. Moreover melanin obtained has significant photoprotective, radical scavenging and metal chelating activity. Thus, B. safensis has the potential to be a new source for the production of melanin, which is of industrial interest.

  7. Raman spectroscopy as a non-invasive technique for the quantification of melanins in feathers and hairs.

    Science.gov (United States)

    Galván, Ismael; Jorge, Alberto; Ito, Kazuma; Tabuchi, Keisuke; Solano, Francisco; Wakamatsu, Kazumasa

    2013-11-01

    The quantification of melanins is a complex task due to the chemical heterogeneity of the pigments and the difficulty of their isolation. The best accepted procedure currently consists in the chemical cleavage of melanins and the subsequent detection of degradation products by HPLC, which implies the destruction of samples. Here, we show that Raman spectroscopy is a non-invasive technique that can be used to quantify melanins. We made parallel analyses of the characteristics of pheomelanin and eumelanin Raman spectra as measured by confocal Raman microscopy and of degradation products of pheomelanin (4-amino-3-hydroxyphenylalanine, 4-AHP) and eumelanin (pyrrole-2,3,5-tricarboxylic acid, PTCA) as measured by HPLC in feathers of red-legged partridges and hairs of wild boars and humans. We found strong correlations between the spectral Raman characteristics and 4-AHP and PTCA levels, which indicates that the Raman spectra of melanins can be used to determine their content. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Quantifying melanin spatial distribution using pump-probe microscopy and a 2-D morphological autocorrelation transformation for melanoma diagnosis

    Science.gov (United States)

    Robles, Francisco E.; Wilson, Jesse W.; Warren, Warren S.

    2013-12-01

    Pump-probe microscopy is an emerging molecular imaging technique that probes the excited state dynamics properties of pigmented samples. This method has been particularly intriguing for melanoma because, unlike other methods available, it can provide nondestructive, quantitative chemical information regarding different types of melanins, with high spatial resolution. In this Letter, we present a method based on mathematical morphology to quantify melanin structure (eumelanin, pheomelanin, and total melanin content, uniquely available with pump-probe microscopy) to aid in melanoma diagnosis. The approach applies a two-dimensional autocorrelation function and utilizes statistical parameters of the corresponding autocorrelation images, specifically, the second moments and entropy, to parameterize image structure. Along with bulk melanin chemical information, we show that this method can differentiate invasive melanomas from noninvasive and benign lesions with high sensitivity and specificity (92.3% and 97.5%, respectively, with N=53). The mathematical method and the statistical analysis are described in detail and results from cutaneous and ocular conjunctival melanocytic lesions are presented.

  9. Esthetic treatment of gingival melanin hyperpigmentation with a Nd:YAG laser and high speed rotary instrument: comparative case report

    Science.gov (United States)

    Ko, Hyuk-Jin; Park, Jin-Woo; Suh, Jo-Young

    2010-01-01

    Purpose The purpose of this study was to evaluate the clinical effectiveness of and patient's satisfaction with treatment of gingival melanin hyperpigmentation with a Nd:YAG laser and a high speed rotary instrument. Methods Three patients with melanin hyperpigmentation in the anterior parts of the gingiva were chosen for this case study. Clinical photographs were taken at the preoperative state and three patients were treated under local anesthesia. In the maxilla, the gingival deepithelization was conducted with a high speed diamond bur, whereas, in the mandible with a Nd:YAG laser. Clinical photographs were taken immediately after the procedures and at the 1st, 2nd, and 4th week to evaluate clinical color changes. A week after the procedure, the patients filled out a questionnaire about any pain or discomfort. At the 4th week after the procedure, the patients filled out questionnaires about esthetic aspects of the results of treatment. Results In all cases, both anterior gingival areas were depigmented with satisfaction and the patients did not complain of severe pain or discomfort. At the 1st week of healing, the gingiva showed moderate to fast epithelization. Two weeks after the procedure, clinically, the gingiva showed almost complete healing. Four weeks after the procedure, there was significant improvement in gingival melanin hyperpigmentation. Conclusions The Nd:YAG laser and the high speed rotary instruments seem to be effective for the esthetic treatment of gingival melanin hyperpigmentation. PMID:20827330

  10. Inhibitory effect of a novel combination of Salvia hispanica (chia) seed and Punica granatum (pomegranate) fruit extracts on melanin production.

    Science.gov (United States)

    Diwakar, Ganesh; Rana, Jatinder; Saito, Lisa; Vredeveld, Doug; Zemaitis, Dorothy; Scholten, Jeffrey

    2014-09-01

    In recent years, dietary fatty acids have been extensively evaluated for nutritional as well as cosmetic benefits. Among the dietary fats, the omega-3 (ω3) and omega-6 (ω6) forms of polyunsaturated fatty acids (PUFAs) have been found to exhibit many biological functions in the skin such as prevention of transepidermal water loss, maintenance of the stratum corneum epidermal barrier, and disruption of melanogenesis in epidermal melanocytes. In this study, we examined the effect of chia seed extract, high in ω3 (linolenic acid) and ω6 (linoleic acid) PUFAs, for its capacity to affect melanogenesis. Chia seed extract was shown to inhibit melanin biosynthesis in Melan-a cells; however, linoleic and α-linolenic acids alone did not effectively reduce melanin content. Further investigation demonstrated that chia seed extract in combination with pomegranate fruit extract had a synergistic effect on the inhibition of melanin biosynthesis with no corresponding effect on tyrosinase activity. Investigation of the possible mechanism of action revealed that chia seed extract downregulated expression of melanogenesis-related genes (Tyr, Tyrp1, and Mc1r), alone and in combination with pomegranate fruit extract, suggesting that the inhibition of melanin biosynthesis by a novel combination of chia seed and pomegranate fruit extracts is possibly due to the downregulation of gene expression of key melanogenic enzymes. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Preparation of a Sepia Melanin and Poly(ethylene-alt-maleic Anhydride) Hybrid Material as an Adsorbent for Water Purification.

    Science.gov (United States)

    Panzarasa, Guido; Osypova, Alina; Consolati, Giovanni; Quasso, Fiorenza; Soliveri, Guido; Ribera, Javier; Schwarze, Francis W M R

    2018-01-23

    Meeting the increasing demand of clean water requires the development of novel efficient adsorbent materials for the removal of organic pollutants. In this context the use of natural, renewable sources is of special relevance and sepia melanin, thanks to its ability to bind a variety of organic and inorganic species, has already attracted interest for water purification. Here we describe the synthesis of a material obtained by the combination of sepia melanin and poly(ethylene- alt -maleic anhydride) (P(E- alt -MA)). Compared to sepia melanin, the resulting hybrid displays a high and fast adsorption efficiency towards methylene blue (a common industrial dye) for a wide pH range (from pH 2 to 12) and under high ionic strength conditions. It is easily recovered after use and can be reused up to three times. Given the wide availability of sepia melanin and P(E- alt -MA), the synthesis of our hybrid is simple and affordable, making it suitable for industrial water purification purposes.

  12. Preparation of a Sepia Melanin and Poly(ethylene-alt-maleic Anhydride Hybrid Material as an Adsorbent for Water Purification

    Directory of Open Access Journals (Sweden)

    Guido Panzarasa

    2018-01-01

    Full Text Available Meeting the increasing demand of clean water requires the development of novel efficient adsorbent materials for the removal of organic pollutants. In this context the use of natural, renewable sources is of special relevance and sepia melanin, thanks to its ability to bind a variety of organic and inorganic species, has already attracted interest for water purification. Here we describe the synthesis of a material obtained by the combination of sepia melanin and poly(ethylene-alt-maleic anhydride (P(E-alt-MA. Compared to sepia melanin, the resulting hybrid displays a high and fast adsorption efficiency towards methylene blue (a common industrial dye for a wide pH range (from pH 2 to 12 and under high ionic strength conditions. It is easily recovered after use and can be reused up to three times. Given the wide availability of sepia melanin and P(E-alt-MA, the synthesis of our hybrid is simple and affordable, making it suitable for industrial water purification purposes.

  13. Melanin and carotenoid ornaments are related to the individual condition in free-living grey partridges (Perdix perdix)

    Czech Academy of Sciences Publication Activity Database

    Svobodová, J.; Gabrielová, B.; Hyršl, P.; Albrecht, Tomáš; Vinkler, M.

    2016-01-01

    Roč. 157, č. 4 (2016), s. 1007-1015 ISSN 0021-8375 Institutional support: RVO:68081766 Keywords : complement * Condition-dependent sexual signalling * Carotenoid and melanin colouration * Game bird * Haematology * Phytohaemagglutinin Subject RIV: EG - Zoology Impact factor: 1.468, year: 2016

  14. Using tyrosinase as a monophenol monooxygenase: A combined strategy for effective inhibition of melanin formation.

    Science.gov (United States)

    Lee, Sang-Hyuk; Baek, Kiheon; Lee, Ju-Eun; Kim, Byung-Gee

    2016-04-01

    Tyrosinase is a binuclear copper-containing metalloprotein that leads the fast and regio-selective o-hydroxylation of monophenols to o-diphenols. However, the subsequent second oxidation to produce o-quinones, i.e., melanin precursors, from the o-diphenols has restricted its use to the production of functional o-diphenol derivatives. Herein, we present a combined strategy for the effective inhibition of melanin formation in tyrosinase reaction, which allows the use of tyrosinase as a monophenol monooxygenase. The o-diphenolic products were protected from being oxidized in the tyrosinase reaction by borate ions and L-ascorbic acid (LAA). Borate-o-diphenol complexes were favorable formed at high pH and consequentially protected the o-diphenolic products from the catecholase activity of tyrosinase. LAA not only directly reduced the byproduct, o-quinones, into o-diphenols but also assisted the completion of the tyrosinase reaction cycle by removing a hydroxyl group attached to the copper metal cluster at the active site of the met-form tyrosinase. The regio-selective o-hydroxylation of 7,4'-dihydroxyisoflavone (daidzein) to produce 7,3',4'-trihydroxyisoflavone (3'-ODI) was successfully carried out by whole E. coli cell biotransformation with heterologously expressed tyrosinase from Bacillus megaterium. The yield of this o-hydroxylation of 5 mM daidzein in one-pot 400 mL reaction was ca. 100% in 90 min and the productivity was 16.3 mg 3'-ODI · L(-1)  ·  h(-1)  ·  DCW mg(-1), which is considerably higher than that of other monooxygenases. The method effectively abolished melanin synthesis, so that the o-diphenolic product remained stable without enzyme inactivation. Other monophenolic phytochemicals such as resveratrol and genistein could be subjected to the same strategy. After 1 h, 1 mM of genistein and resveratrol were both converted to orobol and piceatannol, respectively, with ca. 95% conversion yield. These results support the strong

  15. Light-emitting diode 585nm photomodulation inhibiting melanin synthesis and inducing autophagy in human melanocytes.

    Science.gov (United States)

    Chen, Li; Xu, Zhongyi; Jiang, Min; Zhang, Chengfeng; Wang, Xuan; Xiang, Leihong

    2018-01-01

    Melasma is a common hyperpigmentation skin disease on face. Light-emitting diode (LED) photomodulation (585nm) is reported to be effective for the treatment of melasma. However, whether and how LED photomodulation would influence melanogenesis of human epidermal melanocytes (HEMs) is unknown. To evaluate the effects of LED photomodulation (585nm) on melanogenesis in HEMs. HEMs were irradiated with fluences of 0, 5, 10 and 20J/cm 2 585nm LED light. After 5-day treatment, cell viability was analyzed by CCK-8 assay, and apoptosis was assessed by Annexin V APC assay. Melanin content and tyrosinase activity were measured by spectrophotometer. Melanosome stage and autophagosomes were determined under transmission electron microscope (TEM). The formation of autophagic punctate structures was observed under confocal microscope. RT-PCR and western blotting were used to assess the expression of relative mRNA and protein levels. Yellow light LED 585nm had no effects on HEMs cell viability and apoptosis. Treatment with LED 585nm from 5J/cm 2 to 20J/cm 2 inhibited melanosome maturation, decreased melanin content and tyrosinase activity. Inhibition was accompanied by the decreased expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and microphthalmia-associated transcription factor (MITF) on both mRNA and protein levels. Autophagosomes were observed under TEM. Autophagic punctate structures of microtubule-associated protein light chain 3 (LC3) proteins were induced by LED 585nm light. The configuration change of LC3 from LC3-I to LC3-II, and the degradation of p62 protein were observed after LED 585nm. Furthermore, we also revealed that the anti-melanogenic effect of LED 585nm photomodulation was reversed by 3-Methyladenine (3-MA), which inhibits autophagy by blocking autophagosome formation via the inhibition of type III Phosphatidylinositol 3-kinases (PI-3K). Our finding demonstrated that LED photomodulation with 585nm wavelength suppressed melanin content in

  16. Penurunan Aktivitas Tirosinase dan Jumlah Melanin oleh Fraksi Etil Asetat Buah Malaka (Phyllantus emblica pada Mouse Melanoma B16 Cell-Line

    Directory of Open Access Journals (Sweden)

    Reti Hindritiani

    2013-06-01

    Full Text Available Melanin accumulation can lead to hyperpigmentation, and if it occurs on the face can cause psychosocial problem. Depigmenting agents derived from plants are increasingly utilized. Agents being developed have to be effective in inhibiting melanin synthesis and should not be toxic to melanocyte. This study aimed was to examine the effect of ethyl acetate fraction from Phyllanthus emblica (P. emblica fruit, also known as malaka fruit, towards melanine synthesis, which was measured from the melanin amount and tyrosinase activity, the key regulatory enzyme in melanin synthesis, spectrophotometrically towards melanocytes of mouse melanoma B16 cell-line. The cytotoxic effect towards melanocytes was measured with 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT assay. This study was conducted on November−December 2009 in Department of Biochemistry and Diabetes Research Centre, Chonbuk National University Medical School, South Korea. The result of this study showed that tyrosinase activity and melanin amount decreased in a dose-dependent manner towards various concentrations of ethyl acetate fraction of P. emblica fruit with inhibition concentration (IC 50=95.63 and 16.90 μg/mL, respectively and lethal dose (LD 50 concentration 106.64 μg/mL. In conclusion, ethyl acetate fraction of P. emblica fruit is a potential depigmenting agent, since it can reduce melanin synthesis by inhibition of tyrosinase activity.

  17. Threshold switching in the amorphous semiconductor As/sub 15/Te/sub 70/Ge/sub 15/ and in the organic semiconductor melanin

    Energy Technology Data Exchange (ETDEWEB)

    Culp, C.H. III

    1976-06-01

    The threshold switching properties of the amorphous semiconductor As/sub 15/Te/sub 70/Ge/sub 15/ and the organic semiconductor melanin have been examined with threshold switching experiments. Measurements of delay time, energy and average resistance as functions of applied voltage were made by a computer controlled data acquisition system. These measurements were made on As/sub 15/Te/sub 70/Ge/sub 15/ at 243, 273 and 298/sup 0/K. A time dependent electrothermal model was solved numerically. The material parameters that were measured for this model are activation energy, sample thickness, conductivity at T equal to infinity, and area of the electrodes. With these measured parameters the calculation was compared to the experimental values of delay time, energy, and average resistance as functions of applied voltage. The measured data and the calculations are in good agreement. Melanin was prepared from a lyophilized powder into a hydrated pellet. The melanin pellets were studied at 298, 190, and 77/sup 0/K with a double pulse apparatus. Time dependent current versus voltage characteristics were also measured. Melanin exhibits threshold switching at low electric fields (about 10/sup 2/ V/cm). The results from the melanin experiments show that threshold switching in melanin can be explained by a thermal runaway model. A pseudo-memory effect was also found in melanin.

  18. Interpretation of Ocular Melanin Drug Binding Assays. Alternatives to the Model of Multiple Classes of Independent Sites.

    Science.gov (United States)

    Manzanares, José A; Rimpelä, Anna-Kaisa; Urtti, Arto

    2016-04-04

    Melanin has a high binding affinity for a wide range of drugs. The determination of the melanin binding capacity and its binding affinity are important, e.g., in the determination of the ocular drug distribution, the prediction of drug effects in the eye, and the trans-scleral drug delivery. The binding parameters estimated from a given data set vary significantly when using different isotherms or different nonlinear fitting methods. In this work, the commonly used bi-Langmuir isotherm, which assumes two classes of independent sites, is confronted with the Sips isotherm. Direct, log-log, and Scatchard plots are used, and the interpretation of the binding curves in the latter is critically analyzed. In addition to the goodness of fit, the emphasis is placed on the physical meaning of the binding parameters. The bi-Langmuir model imposes a bimodal distribution of binding energies for the sites on the melanin granules, but the actual distribution is most likely continuous and unimodal, as assumed by the Sips isotherm. Hence, the latter describes more accurately the distribution of binding energies and also the experimental results of melanin binding to drugs and metal ions. Simulations are used to show that the existence of two classes of sites cannot be confirmed on the sole basis of the shape of the binding curve in the Scatchard plot, and that serious doubts may appear on the meaning of the binding parameters of the bi-Langmuir model. Experimental results of melanin binding to chloroquine and metoprolol are used to illustrate the importance of the choice of the binding isotherm and of the method used to evaluate the binding parameters.

  19. Bioinspired Multifunctional Melanin-Based Nanoliposome for Photoacoustic/Magnetic Resonance Imaging-Guided Efficient Photothermal Ablation of Cancer.

    Science.gov (United States)

    Zhang, Liang; Sheng, Danli; Wang, Dong; Yao, Yuanzhi; Yang, Ke; Wang, Zhigang; Deng, Liming; Chen, Yu

    2018-01-01

    Background: The construction of theranostic nanosystems with concurrently high biosafety and therapeutic performance is a challenge but has great significance for the clinical translation of nanomedicine for combating cancer. Methods: Bio-inspired melanin-based nanoliposomes (Lip-Mel) as theranostic agents were constructed for simultaneous photoacoustic (PA) imaging- and T 1 -weighted magnetic resonance (MR) imaging-guided photothermal ablation of tumors, which was demonstrated both in vitro and in vivo . The high biosafety of Lip-Mel was also systematically evaluated. Results: The achieved Lip-Mel nanoliposomes demonstrated their imaging capability for both PA and T 1 -weighted MR imaging (r 1 = 0.25 mM -1 ·s -1 ) both in vitro and in vivo , providing the potential for therapeutic guidance and monitoring. Importantly, the desirable photothermal-conversion efficiency of the as-prepared Lip-Mel achieved complete eradication of tumors in breast cancer-bearing mice, exhibiting remarkable photothermal-based therapeutic performance. In particular, the efficient encapsulation of melanin into the PEGylated liposome mitigated the potential toxicity of melanin and improved the photothermal performance of the loaded melanin. Systematic in vivo biosafety evaluations demonstrated the high biocompatibility of Lip-Mel at a high dose of 100 mg/kg. Conclusion: In this work, we reported a bioinspired strategy where melanin, a natural product in the human body, is encapsulated into PEGylated nanoliposomes for efficient theranostics with high biocompatibility. This work provides a new strategy for creating desirable theranostic agents with concurrent high biocompatibility and satisfactory theranostic performance through the use of materials that totally originate from biosystems.

  20. Melanin protects melanocytes and keratinocytes against H2O2-induced DNA strand breaks through its ability to bind Ca2+.

    Science.gov (United States)

    Hoogduijn, M J; Cemeli, E; Ross, K; Anderson, D; Thody, A J; Wood, J M

    2004-03-10

    Reactive oxygen species (ROS) such as hydrogen peroxide (H(2)O(2)) are produced in the skin under the influence of UV radiation. These compounds are highly reactive and can induce DNA lesions in epidermal cells. Melanin is considered to protect human skin against DNA damage by absorbing UV radiation. We have investigated whether melanin can, in addition, offer protection against the effects of H(2)O(2) in human melanocytes and HaCaT keratinocytes. In the present study, it was shown that 40 and 100 microM H(2)O(2) increased the number of DNA strand breaks as measured using the comet assay, in melanocytes of Caucasian origin. In melanocytes of the same origin in which melanin levels were increased by culturing in presence of 10 mM NH(4)Cl and elevated l-tyrosine, H(2)O(2)-induced DNA damage was reduced compared to that in control melanocytes. Similarly, HaCaT cells that were loaded with melanin were better protected against H(2)O(2)-induced DNA strand breaks than control HaCaT cells. These protective effects of melanin were mimicked by the intracellular Ca(2+)-chelator BAPTA. Thus, BAPTA reduced the level of H(2)O(2)-induced DNA strand breaks in melanocytes. Like BAPTA, melanin is known to be a potent chelator of Ca(2+) and this was confirmed in the present study. It was shown that melanin levels in melanocytic cells correlated directly with intracellular Ca(2+) binding capacity and, in addition, correlated inversely with H(2)O(2)-induced increases in intracellular Ca(2+). Our results show that melanin may have an important role in regulating intracellular Ca(2+) homeostasis and it is suggested that melanin protects against H(2)O(2)-induced DNA strand breaks in both melanocytes and keratinocytes and through its ability to bind Ca(2+).

  1. Role of the melanin-concentrating hormone neuropeptide in sleep regulation.

    Science.gov (United States)

    Peyron, Christelle; Sapin, Emilie; Leger, Lucienne; Luppi, Pierre-Hervé; Fort, Patrice

    2009-11-01

    Melanin-concentrating hormone (MCH), a neuropeptide secreted by a limited number of neurons within the tuberal hypothalamus, has been drawn in the field of sleep only fairly recently in 2003. Since then, growing experimental evidence indicates that MCH may play a crucial role in the homeostatic regulation of paradoxical sleep (PS). MCH-expressing neurons fire specifically during PS. When injected icv MCH induces a 200% increase in PS quantities in rats and the lack of MCH induces a decrease in sleep quantities in transgenic mice. Here, we review recent studies suggesting a role for MCH in the regulation of the sleep-wake cycle, in particular PS, including insights on (1) the specific activity of MCH neurons during PS; (2) how they might be controlled across the sleep-wake cycle; (3) how they might modulate PS; (4) and finally whether MCH might take part in the expression of some symptoms observed in primary sleep disorders.

  2. Electrochemical growth of synthetic melanin thin films by constant potential methods

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Gyun; Nam, Hye Jin; Ahn, Hyeon Ju [Department of Chemistry, School of Chemical Materials Science, Institute of Basic Sciences, Sungkyunkwan Advanced Institute of NanoTechnology (SAINT), Sungkyunkwan University, Chunchun-dong, Gyunggi-do, Suwon 440-746 (Korea, Republic of); Jung, Duk-Young, E-mail: dyjung@skku.ed [Department of Chemistry, School of Chemical Materials Science, Institute of Basic Sciences, Sungkyunkwan Advanced Institute of NanoTechnology (SAINT), Sungkyunkwan University, Chunchun-dong, Gyunggi-do, Suwon 440-746 (Korea, Republic of)

    2011-02-28

    Polymerized melanin thin films were electrochemically synthesized in a 5,6-dihydroxyindole precursor solution on indium tin oxide (ITO) substrates using the cyclic voltammetry and constant potential methods. Tris(hydroxymethyl)aminomethane (THAM) and phosphate buffer solutions were applied to prepare the films that were well deposited to the ITO substrates. The films that were synthesized in the THAM buffer solution exhibited a faster growth rate and better adhesion to the ITO electrodes than the films in the phosphate buffer. The film thickness linearly increased at the growth rate of 0.8 nm/s as the deposition time and number of cycles increased. Two electrochemical conditions produced similar thicknesses as well as physical properties in each buffer solution. However, the constant potential method demonstrated that this provides the synthetic advantages of faster deposition and less consumption of electric charge compared to the cyclic voltammetry route.

  3. Adhesive coatings based on melanin-like nanoparticles for surgical membranes.

    Science.gov (United States)

    Scognamiglio, Francesca; Travan, Andrea; Turco, Gianluca; Borgogna, Massimiliano; Marsich, Eleonora; Pasqua, Mattia; Paoletti, Sergio; Donati, Ivan

    2017-07-01

    Adhesive coatings for implantable biomaterials can be designed to prevent material displacement from the site of implant. In this paper, a strategy based on the use of melanin-like nanoparticles (MNPs) for the development of adhesive coatings for polysaccharidic membranes was devised. MNPs were synthesized in vitro and characterized in terms of dimensions and surface potential, as a function of pH and ionic strength. The in vitro biocompatibility of MNPs was investigated on fibroblast cells, while the antimicrobial properties of MNPs in suspension were evaluated on E. coli and S. aureus cultures. The manufacturing of the adhesive coatings was carried out by spreading MNPs over the surface of polysaccharidic membranes; the adhesive properties of the nano-engineered coating to the target tissue (intestinal serosa) were studied in simulated physiological conditions. Overall, this study opens for novel approaches in the design of naturally inspired nanostructured adhesive systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Novel Inhibitory Effect of N-(2-Hydroxycyclohexylvaliolamine on Melanin Production in a Human Skin Model

    Directory of Open Access Journals (Sweden)

    Bum-Ho Bin

    2014-07-01

    Full Text Available Hyper-pigmentation causes skin darkness and medical disorders, such as post-inflammatory melanoderma and melasma. Therefore, the development of anti-melanogenic agents is important for treating these conditions and for cosmetic production. In our previous paper, we demonstrated that the anti-diabetic drug voglibose, a valiolamine derivative, is a potent anti-melanogenic agent. In addition, we proposed an alternative screening strategy to identify valiolamine derivatives with high skin permeability that act as anti-melanogenic agents when applied topically. In this study, we synthesized several valiolamine derivatives with enhanced lipophilicity and examined their inhibitory effects in a human skin model. N-(2-hydroxycyclohexylvaliolamine (HV possesses a stronger inhibitory effect on melanin production than voglibose in a human skin model, suggesting that HV is a more potent anti-melanogenic agent for the skin.

  5. Organelle-specific injury to melanin-containing cells in human skin by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, G.F.; Shepard, R.S.; Paul, B.S.; Menkes, A.; Anderson, R.R.; Parrish, J.A.

    1983-12-01

    Physical models predict that ultraviolet laser radiation of appropriately brief pulses can selectively alter melanin-containing cellular targets in human skin. Skin of normal human volunteers was exposed to brief (20 nanosecond) 351-nm wave length pulses from a XeF excimer laser, predicting that those cells containing the greatest quantities of melanized melanosomes (lower half of the epidermis) would be selectively damaged. Transmission electron microscopy revealed the earliest cellular alteration to be immediate disruption of melanosomes, both within melanocytes and basal keratinocytes. This disruption was dose dependent and culminated in striking degenerative changes in these cells. Superficial keratinocytes and Langerhans cells were not affected. It was concluded that the XeF excimer laser is capable of organelle-specific injury to melanosomes. These findings may have important clinical implications in the treatment of both benign and malignant pigmented lesions by laser radiations of defined wave lengths and pulse durations.

  6. Genomic regions associated with the sex-linked inhibitor of dermal melanin in Silkie chicken

    Directory of Open Access Journals (Sweden)

    Ming TIAN,Rui HAO,Suyun FANG,Yanqiang WANG,Xiaorong GU,Chungang FENG,Xiaoxiang HU,Ning LI

    2014-09-01

    Full Text Available A unique characteristic of the Silkie chicken is its fibromelanosis phenotype. The dermal layer of its skin, its connective tissue and shank dermis are hyperpigmented. This dermal hyperpigmentation phenotype is controlled by the sex-linked inhibitor of dermal melanin gene (ID and the dominant fibromelanosis allele. This study attempted to confirm the genomic region associated with ID. By genotyping, ID was found to be closely linked to the region between GGA_rs16127903 and GGA_rs14685542 (8406919 bp on chromosome Z, which contains ten functional genes. The expression of these genes was characterized in the embryo and 4 days after hatching and it was concluded that MTAP, encoding methylthioadenosinephosphorylase, would be the most likely candidate gene. Finally, target DNA capture and sequence analysis was performed, but no specific SNP(s was found in the targeted region of the Silkie genome. Further work is necessary to identify the causal ID mutation located on chromosome Z.

  7. EPR persistence measurements of UV-induced melanin free radicals in whole skin

    Energy Technology Data Exchange (ETDEWEB)

    Collins, B.; Poehler, T.O. [Johns Hopkins Univ., Baltimore, MD (United States); Bryden, W.A. [Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Lab.

    1995-09-01

    Electron paramagnetic resonance is used to detect the formation of free radicals caused by exposure to ultraviolet radiation in chemically untreated rabbit skin. A fast jump in EPR signal level, occurring over a few seconds, is observed immediately after a skin sample is exposed to UV. This is followed by a slower increase toward an elevated steady-state signal over a period of hours as the skin is continuously exposed to a UV light source. Upon cessation of UV light exposure, EPR signal levels undergo an abrupt drop followed by a slower decay toward natural levels. Elevated free radical concentrations following UV exposure are found to persist for several hours in whole skin. These results are consistent with time resolved EPR measurements of photoinduced radicals in various natural melanins. (Author).

  8. Pharmacokinetics of Ro 03-8799 in mice bearing melanosarcoma: comparison with tumors without melanin

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, F.; Canal, P.; Soula, G.

    1989-04-01

    The pharmacokinetics of Ro 03-8799 has been studied in melanic and non-melanic tumor bearing mice after iv administration of 150 mg/kg. The peak concentration in B16 melanosarcoma tumor reached 152 micrograms/g, that is 7.6-fold higher than the plasma concentration at the same time. This concentration is 3-times greater than that obtained in the tumor of mice bearing non-melanic sarcoma (DB16) or Lewis lung carcinoma (3LL). The exposure of B16 tumor (AUC) is respectively 15-times and 11-times higher than the 3LL and the DB16 ones. These experimental data confirm that this 2-nitro-imidazol compound has an important affinity for melanin and suggest that it might be used as a radiosensitizer for the treatment of malignant melanoma.

  9. A comparative analysis shows morphofunctional differences between the rat and mouse melanin-concentrating hormone systems.

    Directory of Open Access Journals (Sweden)

    Sophie Croizier

    Full Text Available Sub-populations of neurons producing melanin-concentrating hormone (MCH are characterized by distinct projection patterns, birthdates and CART/NK3 expression in rat. Evidence for such sub-populations has not been reported in other species. However, given that genetically engineered mouse lines are now commonly used as experimental models, a better characterization of the anatomy and morphofunctionnal organization of MCH system in this species is then necessary. Combining multiple immunohistochemistry experiments with in situ hybridization, tract tracing or BrdU injections, evidence supporting the hypothesis that rat and mouse MCH systems are not identical was obtained: sub-populations of MCH neurons also exist in mouse, but their relative abundance is different. Furthermore, divergences in the distribution of MCH axons were observed, in particular in the ventromedial hypothalamus. These differences suggest that rat and mouse MCH neurons are differentially involved in anatomical networks that control feeding and the sleep/wake cycle.

  10. Detection of melanomas. Approach with radiolabeled false precursors of melanin synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Levine, N.; Queen, L.; Chalom, A.

    1983-04-01

    Thiouracil is a thiol-containing pyrimidine that is selectively incorporated into cells that synthesize melanin. In an effort to delineate further the specificity and dynamics of uptake, we injected thiouracil labeled with radioactive carbon into S91 melanoma-bearing mice; biopsy specimens were taken of the tumors and organs at various time intervals thereafter. The data showed a substantial uptake of thiouracil by the melanomas, with peak uptake occurring at 24 hours. All other organs examined showed only minor amounts of radioactivity, which probably reflected the presence of thiouracil in the blood perfusing these tissues. Because of its incorporation into melanomas, the use of radioactive thiouracil has potential as a marker for tumor growth, as a diagnostic tracer compound, and as a carrier for chemotherapeutic agents.

  11. The prospect of using the chitin-melanin-glukancontaining materials in measures of radiating protection

    International Nuclear Information System (INIS)

    Senyuk, O.F.; Myshkovskij, N.M.; Ivchenko, V.G.; Kovalev, V.A.; Gorovoj, L.F.; Kosyakov, V.N.; Kurchenko, V.P.; Sushinskaya, N.V.; Gavrilenko, N.V.

    2004-01-01

    An installation for testing the efficiency of Petryanov fabrics in conditions of the maximal humidity is created. It was shown in research, that chitin-melanin-glukan-containing materials (ChMGM) from higher bazidial fungi has high sorptive ability in relation to isotopes of strontium, uranium, transuranic elements, in particular to americium, and also salts of heavy metals (copper, silver, lead, chromium). Main part of metal ions are quickly absorbed by these materials. The technique of processing them by ChMGM is developed with the purpose to estimate amplification the detaining ability of these filters. High concentration of salts of alkaline and alkaline-earth metals do not essentially influence the absorption level of ChMGM heavy metals and transuranic elements

  12. Digital dermoscopy to determine skin melanin index as an objective indicator of skin pigmentation

    Directory of Open Access Journals (Sweden)

    Sara Majewski

    2016-04-01

    Full Text Available Clinical assessment of skin photosensitivity is subjectively determined by erythema and tanning responses to sunlight recalled by the subject, alternatively known as Fitzpatrick Skin Phototype (SPT. Responses may be unreliable due to recall bias, subjective bias by clinicians and subjects, and lack of cultural sensitivity of the questions. Analysis of red-green-blue (RGB color spacing of digital images may provide an objective determination of SPT. This paper presents the studies to assess the melanin index (MI, as determined by RGB images obtained by both standard digital camera as well as by videodermoscope, and to correlate the MI with SPT based upon subjects’ verbal responses to standardized questions administered by a dermatologist.A sample of subjects representing all SPTs I–VI was selected. Both the digital camera and videodermoscope were calibrated at standard illumination, light source and white balance. Images of constitutive skin of the upper ventral arm were taken of each subject using both instruments.The studies showed that 58 subjects (20 M, 38 F were enrolled in the study (mean age: 47 years; range: 20–89, stratified to skin phototype I–VI. MI obtained by using both digital camera and videodermoscope increased significantly as the SPT increased p = 0.004 and p < 0.0001, respectively and positively correlated with dermatologist-assessed SPT (Spearman correlation, r = 0.48 and r = 0.84, respectively.Digital imaging can quantify melanin content in order to quantitatively approximate skin pigmentation in all skin phototypes including Type VI skin. This methodology holds promise as a simple, non-invasive, rapid and objective approach to reliably determine skin phototype and, with further investigation, may prove to be both practical and useful in the prediction of skin cancer risk.

  13. Size Control and Fluorescence Labeling of Polydopamine Melanin-Mimetic Nanoparticles for Intracellular Imaging

    Directory of Open Access Journals (Sweden)

    Devang R. Amin

    2017-09-01

    Full Text Available As synthetic analogs of the natural pigment melanin, polydopamine nanoparticles (NPs are under active investigation as non-toxic anticancer photothermal agents and as free radical scavenging therapeutics. By analogy to the widely adopted polydopamine coatings, polydopamine NPs offer the potential for facile aqueous synthesis and incorporation of (biofunctional groups under mild temperature and pH conditions. However, clear procedures for the convenient and reproducible control of critical NP properties such as particle diameter, surface charge, and loading with functional molecules have yet to be established. In this work, we have synthesized polydopamine-based melanin-mimetic nanoparticles (MMNPs with finely controlled diameters spanning ≈25 to 120 nm and report on the pH-dependence of zeta potential, methodologies for PEGylation, and the incorporation of fluorescent organic molecules. A comprehensive suite of complementary techniques, including dynamic light scattering (DLS, cryogenic transmission electron microscopy (cryo-TEM, X-ray photoelectron spectroscopy (XPS, zeta-potential, ultraviolet–visible (UV–Vis absorption and fluorescence spectroscopy, and confocal microscopy, was used to characterize the MMNPs and their properties. Our PEGylated MMNPs are highly stable in both phosphate-buffered saline (PBS and in cell culture media and exhibit no cytotoxicity up to at least 100 µg mL−1 concentrations. We also show that a post-functionalization methodology for fluorophore loading is especially suitable for producing MMNPs with stable fluorescence and significantly narrower emission profiles than previous reports, suggesting they will be useful for multimodal cell imaging. Our results pave the way towards biomedical imaging and possibly drug delivery applications, as well as fundamental studies of MMNP size and surface chemistry dependent cellular interactions.

  14. Near-infrared fundus autofluorescence-visualized melanin in the choroidal abnormalities of neurofibromatosis type 1

    Directory of Open Access Journals (Sweden)

    Ueda-Consolvo T

    2012-07-01

    Full Text Available Tomoko Ueda-Consolvo, Akio Miyakoshi, Hironori Ozaki, Satoshi Houki, Atsushi HayashiDepartment of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, JapanPurpose: To report a series of three cases of neurofibromatosis type 1 examined by near-infrared fundus autofluorescence (NIR-AF with a scanning laser ophthalmoscope and spectral-domain optical coherence tomography (OCT to show the characteristics of choroidal abnormalities.Methods: Retrospective case series. Six eyes of three patients were examined by conventional fundus examinations, near-infrared monochromatic light reflectance (NIR-R and NIR-AF, OCT, fluorescein angiography, and indocyanine green angiography.Results: All eyes showed multiple bright patchy regions in the choroid of the posterior pole with NIR-R. NIR-AF revealed high fluorescent regions of similar sizes at fundus locations identical to those shown by NIR-R. In one case, hypofluorescent regions were shown by indocyanine green angiography in the bright fluorescent region shown by NIR-AF. The other two cases showed no abnormality under conventional fundus examination or fluorescein angiography. OCT images crossing the bright patchy region showed irregular hyper-reflectivity in the choroid in two cases and hyporeflectivity in one case.Conclusions: NIR-AF demonstrated that dense melanin was included in the choroidal nodules of neurofibromatosis type 1. The choroidal nodules showed hyper- or hyporeflectivity in the choroid on OCT, which did not affect the retinal structure.Keywords: near-infrared fundus autofluorescence, neurofibromatosis type 1, choroidal nodule, melanin

  15. Size Control and Fluorescence Labeling of Polydopamine Melanin-Mimetic Nanoparticles for Intracellular Imaging.

    Science.gov (United States)

    Amin, Devang R; Sugnaux, Caroline; Lau, King Hang Aaron; Messersmith, Phillip B

    2017-09-01

    As synthetic analogs of the natural pigment melanin, polydopamine nanoparticles (NPs) are under active investigation as non-toxic anticancer photothermal agents and as free radical scavenging therapeutics. By analogy to the widely adopted polydopamine coatings, polydopamine NPs offer the potential for facile aqueous synthesis and incorporation of (bio)functional groups under mild temperature and pH conditions. However, clear procedures for the convenient and reproducible control of critical NP properties such as particle diameter, surface charge, and loading with functional molecules have yet to be established. In this work, we have synthesized polydopamine-based melanin-mimetic nanoparticles (MMNPs) with finely controlled diameters spanning ≈25 to 120 nm and report on the pH-dependence of zeta potential, methodologies for PEGylation, and the incorporation of fluorescent organic molecules. A comprehensive suite of complementary techniques, including dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), X-ray photoelectron spectroscopy (XPS), zeta-potential, ultraviolet-visible (UV-Vis) absorption and fluorescence spectroscopy, and confocal microscopy, was used to characterize the MMNPs and their properties. Our PEGylated MMNPs are highly stable in both phosphate-buffered saline (PBS) and in cell culture media and exhibit no cytotoxicity up to at least 100 μg mL -1 concentrations. We also show that a post-functionalization methodology for fluorophore loading is especially suitable for producing MMNPs with stable fluorescence and significantly narrower emission profiles than previous reports, suggesting they will be useful for multimodal cell imaging. Our results pave the way towards biomedical imaging and possibly drug delivery applications, as well as fundamental studies of MMNP size and surface chemistry dependent cellular interactions.

  16. Seasonal changes in colour: a comparison of structural, melanin- and carotenoid-based plumage colours.

    Directory of Open Access Journals (Sweden)

    Kaspar Delhey

    Full Text Available BACKGROUND: Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult, although whether this affects signalling has not been sufficiently assessed. METHODOLOGY/PRINCIPAL FINDINGS: We studied changes in coloration after moult in four passerine birds (robin, Erithacus rubecula; blackbird, Turdus merula; blue tit, Cyanistes caeruleus; and great tit, Parus major displaying various coloration types (melanin-, carotenoid-based and structural. Birds were caught regularly during three years to measure plumage reflectance. We used models of avian colour vision to derive two variables, one describing chromatic and the other achromatic variation over the year that can be compared in magnitude among different colour types. All studied plumage patches but one (yellow breast of the blue tit showed significant chromatic changes over the year, although these were smaller than for a typical dynamic trait (bill colour. Overall, structural colours showed a reduction in relative reflectance at shorter wavelengths, carotenoid-based colours the opposite pattern, while no general pattern was found for melanin-based colours. Achromatic changes were also common, but there were no consistent patterns of change for the different types of colours. CONCLUSIONS/SIGNIFICANCE: Changes of plumage coloration independent of moult are probably widespread; they should be perceivable by birds and have the potential to affect colour signalling.

  17. Blood supply--susceptible formation of melanin pigment in hair bulb melanocytes of mice.

    Science.gov (United States)

    Maeda, Shogo; Ueda, Koichi; Yamana, Hidenori; Tashiro-Yamaji, Junko; Ibata, Minenori; Mikura, Ayako; Okada, Masashi; Yasuda, Emi; Shibayama, Yuro; Yoshino, Miya; Kubota, Takahiro; Yoshida, Ryotaro

    2015-03-01

    Allogeneic skin grafts onto C57BL/6 mice are rejected, and the rejected skin is replaced by surrounding skin with black hair. In contrast, syngeneic skin grafts are tolerated, and gray hair grows on the grafts. To explore the mechanism of gray hair growing on the tolerated skin grafts, we prepared full-thickness skin (2-cm square) autografts, 2 (2 cm + 2 cm) horizontal or vertical parallel incisions, and U-shaped (2 cm × 2 cm × 2 cm) flaps with or without pedicle vessels. The grafts, incisions, and flaps were fixed by suturing with string and protected by a transparent bandage. On day 14 after the operation, the bandages were removed to observe the color of the hair growing on the skin. Skin autografts from wild-type or hepatocyte growth factor-transgenic (Tg) C57BL/6 mice survived with gray hair, whereas those from steel factor (Kitl)-Tg C57BL/6 mice survived with black hair. In addition, U-shaped flaps lacking both of the 2 main feeding vessels of wild-type mice had gray hair at the tip of the flaps. Light microscopy after staining with hematoxylin and eosin or dihydroxyphenylalanine showed that the formation of melanin pigment in the follicles, but not in the interadnexal skin, was susceptible to the blood supply. Melanin pigment formation in the hair bulb melanocytes appeared to be susceptible to the blood supply, and melanocytosis was promoted in the follicles and in the epidermis of Kitl-Tg C57BL/6 mice.

  18. Coloration principles of nymphaline butterflies - thin films, melanin, ommochromes and wing scale stacking.

    Science.gov (United States)

    Stavenga, Doekele G; Leertouwer, Hein L; Wilts, Bodo D

    2014-06-15

    The coloration of the common butterflies Aglais urticae (small tortoiseshell), Aglais io (peacock) and Vanessa atalanta (red admiral), belonging to the butterfly subfamily Nymphalinae, is due to the species-specific patterning of differently coloured scales on their wings. We investigated the scales' structural and pigmentary properties by applying scanning electron microscopy, (micro)spectrophotometry and imaging scatterometry. The anatomy of the wing scales appears to be basically identical, with an approximately flat lower lamina connected by trabeculae to a highly structured upper lamina, which consists of an array of longitudinal, parallel ridges and transversal crossribs. Isolated scales observed at the abwing (upper) side are blue, yellow, orange, red, brown or black, depending on their pigmentation. The yellow, orange and red scales contain various amounts of 3-OH-kynurenine and ommochrome pigment, black scales contain a high density of melanin, and blue scales have a minor amount of melanin pigment. Observing the scales from their adwing (lower) side always revealed a structural colour, which is blue in the case of blue, red and black scales, but orange for orange scales. The structural colours are created by the lower lamina, which acts as an optical thin film. Its reflectance spectrum, crucially determined by the lamina thickness, appears to be well tuned to the scales' pigmentary spectrum. The colours observed locally on the wing are also due to the degree of scale stacking. Thin films, tuned pigments and combinations of stacked scales together determine the wing coloration of nymphaline butterflies. © 2014. Published by The Company of Biologists Ltd.

  19. Low-melanin containing pullulan production from sugarcane bagasse hydrolysate by Aureobasidium pullulans in fermentations assisted by light-emitting diode.

    Science.gov (United States)

    Terán Hilares, Ruly; Orsi, Camila Ayres; Ahmed, Muhammad Ajaz; Marcelino, Paulo Franco; Menegatti, Carlos Renato; da Silva, Silvio Silvério; Dos Santos, Júlio César

    2017-04-01

    Pullulan is a polymer produced by Aureobasidium pullulans and the main bottleneck for its industrial production is the presence of melanin pigment. In this study, light-emitting diodes (LEDs) of different wavelengths were used to assist the fermentation process aiming to produce low-melanin containing pullulan by wild strain of A. pullulans LB83 with different carbon sources. Under white light using glucose-based medium, 11.75g.L -1 of pullulan with high melanin content (45.70UA 540nm .g -1 ) was obtained, this production improved in process assisted by blue LED light, that resulted in 15.77g.L -1 of pullulan with reduced content of melanin (4.46UA 540nm .g -1 ). By using sugarcane bagasse (SCB) hydrolysate as carbon source, similar concentration of pullulan (about 20g.L -1 ) was achieved using white and blue LED lights, with lower melanin contents in last. Use of LED light was found as a promising approach to assist biotechnological process for low-melanin containing pullulan production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Melanin distribution in human epidermis affords localized protection against DNA photodamage and concurs with skin cancer incidence difference in extreme phototypes.

    Science.gov (United States)

    Fajuyigbe, Damilola; Lwin, Su M; Diffey, Brian L; Baker, Richard; Tobin, Desmond J; Sarkany, Robert P E; Young, Antony R

    2018-02-02

    Epidermal DNA damage, especially to the basal layer, is an established cause of keratinocyte cancers (KCs). Large differences in KC incidence (20- to 60-fold) between white and black populations are largely attributable to epidermal melanin photoprotection in the latter. The cyclobutane pyrimidine dimer (CPD) is the most mutagenic DNA photolesion; however, most studies suggest that melanin photoprotection against CPD is modest and cannot explain the considerable skin color-based differences in KC incidence. Along with melanin quantity, solar-simulated radiation-induced CPD assessed immediately postexposure in the overall epidermis and within 3 epidermal zones was compared in black West Africans and fair Europeans. Melanin in black skin protected against CPD by 8.0-fold in the overall epidermis and by 59.0-, 16.5-, and 5.0-fold in the basal, middle, and upper epidermis, respectively. Protection was related to the distribution of melanin, which was most concentrated in the basal layer of black skin. These results may explain, at least in part, the considerable skin color differences in KC incidence. These data suggest that a DNA protection factor of at least 60 is necessary in sunscreens to reduce white skin KC incidence to a level that is comparable with that of black skin.-Fajuyigbe, D., Lwin, S. M., Diffey, B. L., Baker, R., Tobin, D. J., Sarkany, R. P. E., Young, A. R. Melanin distribution in human epidermis affords localized protection against DNA photodamage and concurs with skin cancer incidence difference in extreme phototypes.

  1. Cloning and identification of a novel tyrosinase and its overexpression in Streptomyces kathirae SC-1 for enhancing melanin production.

    Science.gov (United States)

    Guo, Jing; Rao, Zhiming; Yang, Taowei; Man, Zaiwei; Xu, Meijuan; Zhang, Xian; Yang, Shang-Tian

    2015-04-01

    A 30-kDa novel tyrosinase was purified to homogeneity. The Km for L-Dopa and L-tyrosine were determined as 0.42 and 0.25 mM. The 1231 bp (base pair) melC gene and its 167 bp promoter Pskmel were obtained by thermal asymmetric interlaced polymerase chain reaction based on the amino acids fragment obtained from MS results of the purified enzyme. The protein sequence of tyrosinase shows maximum identity (84%) to tyrosinase from Streptomyces galbus. The melC was introduced into S. kathirae. The melanin production and the transcriptional level of melC in recombinant S. kathirae [pIJPskmelmelC] were about 2.1-fold and 2-fold higher than the wild-type strain, respectively. The melanin concentration was maximized at 28.8 g L(-1). © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Tomographic reconstruction of melanin structures of optical coherence tomography via the finite-difference time-domain simulation

    Science.gov (United States)

    Huang, Shi-Hao; Wang, Shiang-Jiu; Tseng, Snow H.

    2015-03-01

    Optical coherence tomography (OCT) provides high resolution, cross-sectional image of internal microstructure of biological tissue. We use the Finite-Difference Time-Domain method (FDTD) to analyze the data acquired by OCT, which can help us reconstruct the refractive index of the biological tissue. We calculate the refractive index tomography and try to match the simulation with the data acquired by OCT. Specifically, we try to reconstruct the structure of melanin, which has complex refractive indices and is the key component of human pigment system. The results indicate that better reconstruction can be achieved for homogenous sample, whereas the reconstruction is degraded for samples with fine structure or with complex interface. Simulation reconstruction shows structures of the Melanin that may be useful for biomedical optics applications.

  3. Characterization of melanosomes and melanin in Japanese patients with Hermansky-Pudlak syndrome types 1, 4, 6, and 9.

    Science.gov (United States)

    Okamura, Ken; Abe, Yuko; Araki, Yuta; Wakamatsu, Kazumasa; Seishima, Mariko; Umetsu, Takafumi; Kato, Atsushi; Kawaguchi, Masakazu; Hayashi, Masahiro; Hozumi, Yutaka; Suzuki, Tamio

    2018-03-01

    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. All HPS patients had fewer, smaller, and more immature melanosomes than healthy controls. Further, all patients showed reduced total melanin content and increased levels of benzothiazine-type pheomelanin. The results of this study demonstrate the impact of the dysfunctions of BLOCs on the maturation of melanosomes and melanin levels and composition through analysis of their hair samples. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Poly(ethylene oxide) layers grafted to dopamine-melanin anchoring layer: stability and resistance to protein adsorption

    Czech Academy of Sciences Publication Activity Database

    Pop-Georgievski, Ognen; Popelka, Štěpán; Houska, Milan; Chvostová, Dagmar; Proks, Vladimír; Rypáček, František

    2011-01-01

    Roč. 12, č. 9 (2011), s. 3232-3242 ISSN 1525-7797 R&D Projects: GA AV ČR KJB400500904; GA ČR GAP108/11/1857; GA ČR GPP207/10/P569 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10100522 Keywords : dopamine-melanin * polydopamine * poly( ethylene oxide ) Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.479, year: 2011

  5. Melanin concentrating hormone and estrogen receptor-α are coexstensive but not coexpressed in cells of male rat hypothalamus

    OpenAIRE

    Muschamp, John W.; Hull, Elaine M.

    2007-01-01

    In male rats, estradiol (E2) exerts marked anorectic effects. One mechanism proposed for this effect is an E2-mediated down-regulation of the orexigenic neuropeptide melanin concentrating hormone (MCH). Previous anatomical work has shown that both MCH and estrogen receptor α (ERα) are found in quantity in the lateral hypothalamic area (LHA), a structure long associated with appetite and ingestive behavior. It has been hypothesized that the most direct manner by which E2 could affect MCH expre...

  6. Laccases involved in 1,8-dihydroxynaphthalene melanin biosynthesis in Aspergillus fumigatus are regulated by developmental factors and copper homeostasis.

    Science.gov (United States)

    Upadhyay, Srijana; Torres, Guadalupe; Lin, Xiaorong

    2013-12-01

    Aspergillus fumigatus produces heavily melanized infectious conidia. The conidial melanin is associated with fungal virulence and resistance to various environmental stresses. This 1,8-dihydroxynaphthalene (DHN) melanin is synthesized by enzymes encoded in a gene cluster in A. fumigatus, including two laccases, Abr1 and Abr2. Although this gene cluster is not conserved in all aspergilli, laccases are critical for melanization in all species examined. Here we show that the expression of A. fumigatus laccases Abr1/2 is upregulated upon hyphal competency and drastically increased during conidiation. The Abr1 protein is localized at the surface of stalks and conidiophores, but not in young hyphae, consistent with the gene expression pattern and its predicted role. The induction of Abr1/2 upon hyphal competency is controlled by BrlA, the master regulator of conidiophore development, and is responsive to the copper level in the medium. We identified a developmentally regulated putative copper transporter, CtpA, and found that CtpA is critical for conidial melanization under copper-limiting conditions. Accordingly, disruption of CtpA enhanced the induction of abr1 and abr2, a response similar to that induced by copper starvation. Furthermore, nonpigmented ctpAΔ conidia elicited much stronger immune responses from the infected invertebrate host Galleria mellonella than the pigmented ctpAΔ or wild-type conidia. Such enhancement in eliciting Galleria immune responses was independent of the ctpAΔ conidial viability, as previously observed for the DHN melanin mutants. Taken together, our findings indicate that both copper homeostasis and developmental regulators control melanin biosynthesis, which affects conidial surface properties that shape the interaction between this pathogen and its host.

  7. Recognition of DHN-melanin by a C-type lectin receptor is required for immunity to Aspergillus.

    Science.gov (United States)

    Stappers, Mark H T; Clark, Alexandra E; Aimanianda, Vishukumar; Bidula, Stefan; Reid, Delyth M; Asamaphan, Patawee; Hardison, Sarah E; Dambuza, Ivy M; Valsecchi, Isabel; Kerscher, Bernhard; Plato, Anthony; Wallace, Carol A; Yuecel, Raif; Hebecker, Betty; da Glória Teixeira Sousa, Maria; Cunha, Cristina; Liu, Yan; Feizi, Ten; Brakhage, Axel A; Kwon-Chung, Kyung J; Gow, Neil A R; Zanda, Matteo; Piras, Monica; Zanato, Chiara; Jaeger, Martin; Netea, Mihai G; van de Veerdonk, Frank L; Lacerda, João F; Campos, António; Carvalho, Agostinho; Willment, Janet A; Latgé, Jean-Paul; Brown, Gordon D

    2018-02-28

    Resistance to infection is critically dependent on the ability of pattern recognition receptors to recognize microbial invasion and induce protective immune responses. One such family of receptors are the C-type lectins, which are central to antifungal immunity. These receptors activate key effector mechanisms upon recognition of conserved fungal cell-wall carbohydrates. However, several other immunologically active fungal ligands have been described; these include melanin, for which the mechanism of recognition is hitherto undefined. Here we identify a C-type lectin receptor, melanin-sensing C-type lectin receptor (MelLec), that has an essential role in antifungal immunity through recognition of the naphthalene-diol unit of 1,8-dihydroxynaphthalene (DHN)-melanin. MelLec recognizes melanin in conidial spores of Aspergillus fumigatus as well as in other DHN-melanized fungi. MelLec is ubiquitously expressed by CD31 + endothelial cells in mice, and is also expressed by a sub-population of these cells that co-express epithelial cell adhesion molecule and are detected only in the lung and the liver. In mouse models, MelLec was required for protection against disseminated infection with A. fumigatus. In humans, MelLec is also expressed by myeloid cells, and we identified a single nucleotide polymorphism of this receptor that negatively affected myeloid inflammatory responses and significantly increased the susceptibility of stem-cell transplant recipients to disseminated Aspergillus infections. MelLec therefore recognizes an immunologically active component commonly found on fungi and has an essential role in protective antifungal immunity in both mice and humans.

  8. A novel bioactive chalcone of Morus australis inhibits tyrosinase activity and melanin biosynthesis in B16 melanoma cells.

    Science.gov (United States)

    Takahashi, Makoto; Takara, Kensaku; Toyozato, Tomonao; Wada, Koji

    2012-01-01

    The methanol extract of Morus australis (shimaguwa) acts as a whitening agent due to the inhibition of tyrosinase activity. In order to explore the mechanism(s) of the whitening action, constituents of the 95% methanol extract from the dried stems of shimaguwa were isolated and their skin-whitening capacity was examined. Bioassay-guided fractionation of the methanol soluble extract of shimaguwa led to the isolation of 2, 4, 2', 4'-hydroxycalcone (chalcone 1) and three analogues of chalcone 1 with 3'-substituted resorcinol moieties (chalcones 2-4). Chalcone derivative 4 proved to be a novel compound and was fully characterized. Chalcones 1-4 were evaluated for inhibition activity on mushroom tyrosinase using L-tyrosine as the substrate. The parent chalcone 1 was a highly effective inhibitor of tyrosinase activity (IC₅₀ = 0.21 μM) compared to arbutin (IC₅₀ = 164 μM). Compared to chalcone 1, chalcones 2 and 3, which possess 3'-substituted isoprenyl or bulky 2-benzoylbiphenyl, showed significantly decreased tyrosinase activity, while chalcone 4, possessing 3'-substituted 2-hydroxy-1-pentene group, showed slightly increased activity.The effects of chalcones 1-4 on melanin synthesis, without affecting cell growth, were assayed in melanin-producing B16 murine melanoma cells. Chalcone 3 significantly reduced cell viability before reaching the IC₅₀ value for melanin synthesis. In contrast, the inhibitory effects of chalcones 1, 2 and 4 were more than 100-fold greater than that of arbutin, with little or no cytotoxicity. More significantly, chalcone 2, which exhibited less tyrosinase inhibitory activity compared to the parent chalcone 1, showed the highest inhibition of melanin synthesis in B16 cells among the chalcones tested. Accordingly, chalcones 1 and 2, and the novel chalcone 4 might be the active components responsible for the whitening ability of shimaguwa. Moreover, whitening ability was not exclusively due to tyrosinase inhibition.

  9. Mapping of Id locus for dermal shank melanin in a Chinese indigenous chicken breed.

    Science.gov (United States)

    Xu, Jiguo; Lin, Shudai; Gao, Xinfeng; Nie, Qinghua; Luo, Qingbin; Zhang, Xiquan

    2017-12-01

    The dermal shank pigmentation, one of the defining traits of chicken breeds, is caused by an abnormal deposition of melanin in the dermis of the shank. The abnormal deposition is controlled by the sex-linked inhibitor of dermal melanin (Id). In this study, we aim to locate the gene responsible for the dermal shank pigmentation in chickens by an association analysis and a differential expression analysis. Based on our results, 72 single-nucleotide polymorphisms (SNPs) located in Z chromosome (chrZ): 71-73 Mb (galGal3) were selected to further explore their relationships with the dermal shank pigmentation in pure lines of 96 Gushi hens and 96 Gushi hens with a yellow shank skin colour. The results of the association analysis showed that the SNPs located in chrZ: 72.58-72.99 Mb (galGal3) (chrZ: 79.02-79.44 Mb (galGal4)) are significantly associated with the dermal shank pigmentation. Based on the results of our previous studies and the present association analysis, the zinc-finger protein 608 (ZNF608), GRAM domain containing 3 (GRAMD3), aldehyde dehydrogenase 7 family member A1 (ALDH7A1), fem-1 homologue C (FEM1C), beta-1,4-galactosyltransferase 1 (B4GALT1) and versican (VCAN) genes were selected for the differential expression analysis. The gene expression profiles showed that the expression of GRAMD3 gene in the dermis tissues of the shank was significantly (P = 0.010738 < 0.05) higher in 350-day-old Gushi chickens characterized by the dermal shank pigmentation than in one-day-old Gushi chickens. The dermal shank pigmentation was not present in the one-day-old Gushi chickens. Additionally, the results of the association analysis and the expression analysis showed that GRAMD3 could be the most likely candidate gene for the Id locus. However, we did not detect a mutation, i.e. significantly associated with this trait within GRAMD3. Therefore, we concluded that the variations located in the flanking region of GRAMD3 led to the abnormal expression of GRAMD3, which

  10. Nanoarchitecturing of Natural Melanin Nanospheres by Layer-by-Layer Assembly: Macroscale Anti-inflammatory Conductive Coatings with Optoelectronic Tunability.

    Science.gov (United States)

    Eom, Taesik; Woo, Kyungbae; Cho, Whirang; Heo, Jae Eun; Jang, Daseul; Shin, Jae In; Martin, David C; Wie, Jeong Jae; Shim, Bong Sup

    2017-06-12

    Natural melanins are biocompatible conductors with versatile functionalities. Here, we report fabrication of multifunctional poly(vinyl alcohol)/melanin nanocomposites by layer-by-layer (LBL) assembly using melanin nanoparticles (MNPs) directly extracted from sepia officinalis inks. The LBL assembly offers facile manipulation of nanotextures as well as nm-thickness control of the macroscale film by varying solvent qualities. The time-resolved absorption was monitored during the process and quantitatively studied by fractal dimension and lacunarity analysis. The capability of nanoarchitecturing provides confirmation of complete monolayer formation and leads to tunable iridescent reflective colors of the MNP films. In addition, the MNP films have durable electrochemical conductivities as evidenced by enhanced charge storage capacities for 1000 cycles. Moreover, the MNP covered ITO (indium tin oxide) substrates significantly reduced secretion of inflammatory cytokines, TNF-α, by raw 264.7 macrophage cells compared to bare ITO, by a factor of 5 and 1.8 with and without lipopolysaccharide endotoxins, respectively. These results highlight the optoelectronic device-level tunability along with the anti-inflammatory biocompatibility of the MNP LBL film. This combination of performance should make these films particularly interesting for bioelectronic device applications such as electroceuticals, artificial bionic organs, biosensors, and implantable devices.

  11. Determination of the optical properties of melanin-pigmented human skin equivalents using terahertz time-domain spectroscopy

    Science.gov (United States)

    Lipscomb, Dawn; Echchgadda, Ibtissam; Peralta, Xomalin G.; Wilmink, Gerald J.

    2013-02-01

    Terahertz time-domain spectroscopy (THz-TDS) methods have been utilized in previous studies in order to characterize the optical properties of skin and its primary constituents (i.e., water, collagen, and keratin). However, similar experiments have not yet been performed to investigate whether melanocytes and the melanin pigment that they synthesize contribute to skin's optical properties. In this study, we used THz-TDS methods operating in transmission geometry to measure the optical properties of in vitro human skin equivalents with or without normal human melanocytes. Skin equivalents were cultured for three weeks to promote gradual melanogenesis, and THz time domain data were collected at various time intervals. Frequency-domain analysis techniques were performed to determine the index of refraction (n) and absorption coefficient (μa) for each skin sample over the frequency range of 0.1-2.0 THz. We found that for all samples as frequency increased, n decreased exponentially and the μa increased linearly. Additionally, we observed that skin samples with higher levels of melanin exhibited greater n and μa values than the non-pigmented samples. Our results indicate that melanocytes and the degree of melanin pigmentation contribute in an appreciable manner to the skin's optical properties. Future studies will be performed to examine whether these contributions are observed in human skin in vivo.

  12. Estimation of Melanin and Hemoglobin Using Spectral Reflectance Images Reconstructed from a Digital RGB Image by the Wiener Estimation Method

    Directory of Open Access Journals (Sweden)

    Yoshihisa Aizu

    2013-06-01

    Full Text Available A multi-spectral diffuse reflectance imaging method based on a single snap shot of Red-Green-Blue images acquired with the exposure time of 65 ms (15 fps was investigated for estimating melanin concentration, blood concentration, and oxygen saturation in human skin tissue. The technique utilizes the Wiener estimation method to deduce spectral reflectance images instantaneously from an RGB image. Using the resultant absorbance spectrum as a response variable and the extinction coefficients of melanin, oxygenated hemoglobin and deoxygenated hemoglobin as predictor variables, multiple regression analysis provides regression coefficients. Concentrations of melanin and total blood are then determined from the regression coefficients using conversion vectors that are numerically deduced in advance by the Monte Carlo simulations for light transport in skin. Oxygen saturation is obtained directly from the regression coefficients. Experiments with a tissue-like agar gel phantom validated the method. In vivo experiments on fingers during upper limb occlusion demonstrated the ability of the method to evaluate physiological reactions of human skin.

  13. Uptake of 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene in melanin-containing tissues

    Energy Technology Data Exchange (ETDEWEB)

    Roberto, A.; Larsson, B.S. [Uppsala Univ., Dept. of Pharmaceutical Biosciences, Div. of Toxicology, Uppsala (Sweden); Tjaelve, H. [The Swedish Univ. of Agricultural Sciences, Dept. of Pharmacology and Toxicology, Uppsala (Sweden)

    1996-08-01

    It is widely accepted that UV exposure is the main etiological factor for malignant melanoma. Epidemiologic studies, however, have indicated that also chemical carcinogens may be a risk factor for the disease. Polycyclic aromatic hydrocarbons such as 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene represent an important class of carcinogenic chemicals. It is known that 7,12-dimethylbenz(a)anthracene can induce melanotic tumours in various animal species, and human melanocytes in culture have been found to be capable of metabolizing benzo(a)pyrene to its proximate carcinogen benzo(a)pyrene-7,8-diol. In the present study the disposition of {sup 14}C- and {sup 3}H-7,12-dimethylbenz(a)anthracene and {sup 14}C-benzo(a)pyrene was studied in pigmented and albino mice and Syrian golden hamsters by whole-body autoradiography. The results showed pronounced retention of label in the melanin-containing structures of the eyes and the hair follicles in the pigmented animals. The labelling of the corresponding structures in the albino animals was low. Additional experiments showed that 7,12-dimethylbenz(a)anthracene and benzo(a)pyrene as well as some of their metabolites are bound to melanin in vitro. The specific localization of the polycyclic aromatic hydrocarbons in pigmented tissues due to melanin affinity, combined with bioactivating capacity of melanocytes, suggest that these substances may play a role in the induction of malignant melanoma. (au).

  14. Relationship of the eye uptake of N-isopropyl-p-(/sup 123/I)iodoamphetamine to melanin production

    Energy Technology Data Exchange (ETDEWEB)

    Holman, B.L.; Wick, M.M.; Kaplan, M.L.; Hill, T.C.; Lee, R.G.L.; Wu, J.; Lin, T.H.

    1984-03-01

    Eye uptake has been a potential concern with N-isopropyl-p-(/sup 123/I)iodoamphetamine (I-123 IMP) because it has been observed in certain animal species. The authors have investigated the cause of the eye uptake and its relationship to melanin synthesis. In a 1-yr-old cynomolgus monkey, high concentration of the tracer was seen in the eyes regardless of the type of anesthesia (pentobarbital or ketamine) or the oral administration of Lugol's solution. The eye uptake at 24 hr after injection of I-123 IMP was equally high in an 8-yr-old rhesus monkey. The ratio of radioactivity in the eye of black compared with white albino mice was 10:1 at 30 min, 18:1 at 2 hr and 36:1 at 24 hr after injection if I-123 IMP. No eye uptake above soft-tissue background was seen in five patients at 2, 24, and 48 hr after injection. I-123 IMP is avidly incorporated into melanocytes actively producing melanin, but substantially less in melanocytes where production of melanin has ceased as in the human eye.

  15. Bleaching of melanin in the epidermis of South American fur seal and its application on enzyme immunohistochemistry

    Directory of Open Access Journals (Sweden)

    A.P. Silva

    2011-03-01

    Full Text Available The South American fur seal (Arctocephalus australis is an amphibious marine mammal distributed along the Atlantic and Pacific coasts of South America. The species is well adjusted to different habitats due to the morphology of its fin-like members and due to some adaptations in their integumentary system. Immunohistochemical studies are very important to evaluate the mechanisms of skin adaptation due the differential expression of the antigens present in the tissue depending of the region of the body surface. However, its strongly pigmented (melanin epidermis prevents the visualization of the immuno-histochemical chromogens markers. In this study a melanin bleaching method was developed aimed to allow the visualization of the chromogens without interfering in the antigen-antibody affinity for immunohistochemistry. The analysis of PCNA (proliferating cell nuclear antigen index in the epidermis of A. australis by immunohistochemistry with diaminobenzidine (DAB as chromogen was used to test the method. The bleaching of the melanin allowed to obtain the cell proliferation index in epidermis and to avoid false positive results without affecting the immunohistochemical results.

  16. Inhibitory effect of 660-nm LED on melanin synthesis in in vitro and in vivo.

    Science.gov (United States)

    Oh, Chang Taek; Kwon, Tae-Rin; Choi, Eun Ja; Kim, Soon Re; Seok, Joon; Mun, Seog Kyun; Yoo, Kwang Ho; Choi, Yeon Shik; Choi, Sun Young; Kim, Beom Joon

    2017-01-01

    Skin hyperpigmentary disorders including postinflammatory hyperpigmentation, melasma, solar lentigines, and conditions like freckles are common. The light-emitting diodes (LEDs) are the latest category of nonthermal and noninvasive phototherapy to be considered in skin pigmentation disorder treatment. The purpose of this study was to investigate the effects of 660-nm LED on inhibition of melanogenesis. We investigated whether a 660-nm LED affected melanin synthesis in in vitro and in vivo models, and we explored the mechanisms involved. The inhibitory effect of 660-nm LED on melanin synthesis was evaluated in B16F10 cells and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of 660-nm LED. Interestingly, 660-nm LED inhibited alpha-melanocyte-stimulating hormone-induced tyrosinase activity in B16F10 cells. We also found that 660-nm LED decreased MITF and tyrosinase expression and induced the activation of ERK. These findings suggest that the depigmenting effects of 660-nm LED result from downregulation of MITF and tyrosinase expression due to increased ERK activity. The 660-nm LED reduced UVB-induced melanogenesis in the skin of HRM-2 via downregulation of tyrosinase and MITF. These findings suggest 660-nm LED is a potentially depigmentation strategy. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Mediation of cholino-piperine like receptors by extracts of Piper nigrum induces melanin dispersion in Rana tigerina tadpole melanophores.

    Science.gov (United States)

    Sajid, Mohammed; Ali, Sharique A

    2011-08-01

    The present study was carried out to determine the effects of lyophilized dried fruit extracts of Piper nigrum and pure piperine on the tadpole melanophores of frog Rana tigerina which offer excellent in vitro opportunities for studying the effects of pharmacological and pharmaceutical agents. The nature of specific cellular receptors present on the neuro-melanophore junction and their involvement in pigmentary responses has been explored. Effects of lyophilized extracts of P. nigrum and pure piperine were studied on the isolated tail melanophores of tadpoles of the frog R. tigerina as per the modified method. The extract of P. nigrum and its active ingredient piperine caused significant melanin dispersal responses leading to darkening of the tail melanophores, which were completely antagonized by atropine and hyoscine. These per se melanin dispersal effects were also found to be markedly potentiated by neostigmine an anticholinesterase agent. It appears that the melanin dispersal effects of the extracts of P. nigrum and pure piperine leading to skin darkening are mediated by cholinergic muscarinic or piperine-like receptors having similar properties.

  18. Relationship of the eye uptake of N-isopropyl-p-[123I]iodoamphetamine to melanin production

    International Nuclear Information System (INIS)

    Holman, B.L.; Wick, M.M.; Kaplan, M.L.; Hill, T.C.; Lee, R.G.L.; Wu, J.; Lin, T.H.

    1984-01-01

    Eye uptake has been a potential concern with N-isopropyl-p-[ 123 I]iodoamphetamine (I-123 IMP) because it has been observed in certain animal species. The authors have investigated the cause of the eye uptake and its relationship to melanin synthesis. In a 1-yr-old cynomolgus monkey, high concentration of the tracer was seen in the eyes regardless of the type of anesthesia (pentobarbital or ketamine) or the oral administration of Lugol's solution. The eye uptake at 24 hr after injection of I-123 IMP was equally high in an 8-yr-old rhesus monkey. The ratio of radioactivity in the eye of black compared with white albino mice was 10:1 at 30 min, 18:1 at 2 hr and 36:1 at 24 hr after injection if I-123 IMP. No eye uptake above soft-tissue background was seen in five patients at 2, 24, and 48 hr after injection. I-123 IMP is avidly incorporated into melanocytes actively producing melanin, but substantially less in melanocytes where production of melanin has ceased as in the human eye

  19. Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival

    Directory of Open Access Journals (Sweden)

    Ayat Al-Laaeiby

    2016-03-01

    Full Text Available The dematiaceous (melanised fungus Lomentospora (Scedosporium prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H2O2, UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN-melanin biosynthetic enzymes polyketide synthase (PKS1, tetrahydroxynapthalene reductase (4HNR and scytalone dehydratase (SCD1. Infectious propagules (spores of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H2O2 treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

  20. Identification of a phenoloxidase- and melanin-dependent defence mechanism in Achatina fulica infected with Angiostrongylus vasorum.

    Science.gov (United States)

    Coaglio, Aytube Lucas; Ferreira, Mônica Alves Neves Diniz; Dos Santos Lima, Walter; de Jesus Pereira, Cíntia Aparecida

    2018-02-27

    Angiostrongylus vasorum has different freshwater aquatic and terrestrial gastropod molluscs as an intermediate host, e.g. Arion spp. The mollusc Achatina fulica is a danger to public health, given the large diversity of nematodes utilizing it as an intermediate host, such as the parasites of the genus Angiostrongylus, of importance in human and veterinary medicine. Achatina fulica has been shown to have an excellent capacity for maintaining outbreaks and natural infections with A. cantonensis in Asia. Within the mollusc, the nematode parasites activate haemocytes and/or haemolymph factors and in some invertebrates, phenoloxidase (PO), that induces the release of toxic elements and eliminates the parasites. Despite the importance of A. fulica in the life-cycle of nematodes, little is known regarding the defence mechanisms involving PO in molluscs infected with nematodes. Here, the presence of PO and nitric oxide (NO) in the haemolymph and haemocytes of A. fulica infected with first-stage (L1) larvae of Angiostrongylus vasorum was evaluated, together with the presence of melanin in the cephalopod mollusc tissue. An increase in PO at one day post infection (dpi), in comparison with the control using the substrates L-tyrosine (F (4,90)  = 6.73, P = 0.00006), L-DOPA (F (4,90)  = 22.67, P = 0.02) and p-phenylenediamine (PPD) (F (4,90)  = 27.58, P = 0.0019), was observed. PO increase coincided with the presence of melanin in the cephalopodal tissue. At 8 dpi, PO activity, compared to L-DOPA (F (4,90)  = 22.67, P = 0.00002) and PPD (F (4,90)  = 27.58, P = 0.079) decreased, while melanin increased. At 13 dpi, PO decreased with PPD (F (4,90)  = 27.58, P = 0.000015) and also the amount of melanin observed in histology. At 30 dpi, PO increased along with the substrates L-DOPA and PPD, while melanin decreased. NO levels increased until 8 dpi, and decreased after 13 dpi. To our knowledge, this is the first study that

  1. Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival.

    Science.gov (United States)

    Al-Laaeiby, Ayat; Kershaw, Michael J; Penn, Tina J; Thornton, Christopher R

    2016-03-24

    The dematiaceous (melanised) fungus Lomentospora (Scedosporium) prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H₂O₂), UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN)-melanin biosynthetic enzymes polyketide synthase (PKS1), tetrahydroxynapthalene reductase (4HNR) and scytalone dehydratase (SCD1). Infectious propagules (spores) of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H₂O₂ treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

  2. Safety and Efficacy of 188-Rhenium-Labeled Antibody to Melanin in Patients with Metastatic Melanoma

    Directory of Open Access Journals (Sweden)

    M. Klein

    2013-01-01

    Full Text Available There is a need for effective “broad spectrum” therapies for metastatic melanoma which would be suitable for all patients. The objectives of Phase Ia/Ib studies were to evaluate the safety, pharmacokinetics, dosimetry, and antitumor activity of 188Re-6D2, a 188-Rhenium-labeled antibody to melanin. Stage IIIC/IV metastatic melanoma (MM patients who failed standard therapies were enrolled in both studies. In Phase Ia, 10 mCi 188Re-6D2 were given while unlabeled antibody preload was escalated. In Phase Ib, the dose of 188Re-6D2 was escalated to 54 mCi. SPECT/CT revealed 188Re-6D2 uptake in melanoma metastases. The mean effective half-life of 188Re-6D2 was 12.4 h. Transient HAMA was observed in 9 patients. Six patients met the RECIST criteria for stable disease at 6 weeks. Two patients had durable disease stabilization for 14 weeks and one for 22 weeks. Median overall survival was 13 months with no dose-limiting toxicities. The data demonstrate that 188Re-6D2 was well tolerated, localized in melanoma metastases, and had antitumor activity, thus warranting its further investigation in patients with metastatic melanoma.

  3. Dynamics of melanin-concentrating hormone (MCH) serum levels in major depressive disorder during antidepressant treatment.

    Science.gov (United States)

    Schmidt, Frank M; Nowak, Claudia; Kratzsch, Juergen; Sander, Christian; Hegerl, Ulrich; Schönknecht, Peter

    2015-07-15

    In preclinical studies, the hypothalamic polypeptide melanin-concentrating hormone (MCH) has been shown to be involved in depression-like behavior and modulations of MCH and MCH-receptors were proposed as potential new antidepressant drug targets. For the first time, MCH serum levels were explored in 30 patients with major depressive disorder (MDD) prior to (T1) and after 2 (T2) and 4 weeks (T3) of antidepressant treatment and in 30 age- and sex-matched healthy controls by applying a fluorescence immunoassay. Levels of MCH did not differ significantly between un-medicated patients (444.11±174.63pg/mL SD) and controls (450.68±210.03pg/mL SD). In MDD patients, MCH levels significantly decreased from T1 to T3 (F=4.663; p=0.013). Post-hoc analyses showed that these changes were limited to patients treated with mirtazapine but not escitalopram and female but not male patients. MCH-levels showed high correlations from T1 to T3 (r≥0.964, pdepression but possibly reflecting depression-related state properties that can be modulated by sleep, medication and sex. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Application of melanin-free ink as a new antioxidative gel enhancer in sardine surimi gel.

    Science.gov (United States)

    Vate, Naveen Kumar; Benjakul, Soottawat; Agustini, Tri Winarni

    2015-08-30

    The squid ink that is discarded as waste during processing can be effectively utilised as a gel enhancer in surimi gels, especially those prepared from dark-fleshed fish which have poor gel properties. It also acts as an antioxidant, inhibiting lipid oxidation. This investigation aimed to study the effect of melanin-free ink (MFI) from splendid squid (Loligo formosana) on properties and oxidative stability of surimi gel from sardine (Sardinella albella). MFI (0-0.1 g kg(-1) surimi) increased the breaking force and deformation of sardine surimi gel in a dose-dependent manner (P 0.05). The expressible moisture content of gels decreased as the levels of MFI increased (P < 0.05). Based on a microstructure study, gel added with MFI at a level of 0.08 g kg(-1) surimi was denser and finer than that of the control (without MFI). Surimi gels with MFI had lower peroxide values, thiobarbituric acid reactive substances, nonanal and 2-decenal. MFI could improve the properties of sardine surimi gel. Additionally, it was able to prevent lipid oxidation in surimi gels during refrigerated storage. © 2014 Society of Chemical Industry.

  5. A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep

    Science.gov (United States)

    Verret, Laure; Goutagny, Romain; Fort, Patrice; Cagnon, Laurène; Salvert, Denise; Léger, Lucienne; Boissard, Romuald; Salin, Paul; Peyron, Christelle; Luppi, Pierre-Hervé

    2003-01-01

    Background Peptidergic neurons containing the melanin-concentrating hormone (MCH) and the hypocretins (or orexins) are intermingled in the zona incerta, perifornical nucleus and lateral hypothalamic area. Both types of neurons have been implicated in the integrated regulation of energy homeostasis and body weight. Hypocretin neurons have also been involved in sleep-wake regulation and narcolepsy. We therefore sought to determine whether hypocretin and MCH neurons express Fos in association with enhanced paradoxical sleep (PS or REM sleep) during the rebound following PS deprivation. Next, we compared the effect of MCH and NaCl intracerebroventricular (ICV) administrations on sleep stage quantities to further determine whether MCH neurons play an active role in PS regulation. Results Here we show that the MCH but not the hypocretin neurons are strongly active during PS, evidenced through combined hypocretin, MCH, and Fos immunostainings in three groups of rats (PS Control, PS Deprived and PS Recovery rats). Further, we show that ICV administration of MCH induces a dose-dependant increase in PS (up to 200%) and slow wave sleep (up to 70%) quantities. Conclusion These results indicate that MCH is a powerful hypnogenic factor. MCH neurons might play a key role in the state of PS via their widespread projections in the central nervous system. PMID:12964948

  6. Characterization of the melanin-concentrating hormone neurons activated during paradoxical sleep hypersomnia in rats.

    Science.gov (United States)

    Hanriot, Lucie; Camargo, Nutabi; Courau, Anne Claire; Leger, Lucienne; Luppi, Pierre Hervé; Peyron, Christelle

    2007-11-10

    Although the main nodes of the neuronal network that regulate paradoxical sleep (PS), also called rapid eye movement sleep, have been identified in rodents, it still needs to be more thoroughly described. We have recently shown that 58% of a hypothalamic neuronal population, the melanin-concentrating hormone (MCH) neurons, are activated after a PS hypersomnia and that MCH, when injected intracerebroventricularly, induces a dose-dependent increase in PS. This suggests that MCH plays a role in PS regulation. Two subpopulations of MCH neurons have been distinguished neurochemically, one that coexpresses cocaine and amphetamine-regulated transcript (CART) and sends ascending projections to the septum and the hippocampus, the other, the non-CART MCH neurons, send descending projections to the lower brainstem and the spinal cord. In order to better characterize the PS-activated MCH neurons it is interesting to determine whether they belong to the first, the second, or both subgroups. We therefore undertook an MCH, CART, and Fos triple immunolabeling study in PS hypersomniac rats. We showed that the MCH neurons activated during PS are part of both subpopulations since we found CART and non-CART MCH-activated neurons. Based on these results and the literature, we propose that MCH could be involved in memory processes and in the inhibition of muscle tone during PS. 2007 Wiley-Liss, Inc

  7. Sleep architecture of the melanin-concentrating hormone receptor 1-knockout mice.

    Science.gov (United States)

    Adamantidis, Antoine; Salvert, Denise; Goutagny, Romain; Lakaye, Bernard; Gervasoni, Damien; Grisar, Thierry; Luppi, Pierre-Hervé; Fort, Patrice

    2008-04-01

    Growing amounts of data indicate involvement of the posterior hypothalamus in the regulation of sleep, especially paradoxical sleep (PS). Accordingly, we previously showed that the melanin-concentrating hormone (MCH)-producing neurons of the rat hypothalamus are selectively activated during a PS rebound. In addition, intracerebroventricular infusion of MCH increases total sleep duration, suggesting a new role for MCH in sleep regulation. To determine whether activation of the MCH system promotes sleep, we studied spontaneous sleep and its homeostatic regulation in mice with deletion of the MCH-receptor 1 gene (MCH-R1-/- vs. MCH-R1+/+) and their behavioural response to modafinil, a powerful antinarcoleptic drug. Here, we show that the lack of functional MCH-R1 results in a hypersomniac-like phenotype, both in basal conditions and after total sleep deprivation, compared to wild-type mice. Further, we found that modafinil was less potent at inducing wakefulness in MCH-R1-/- than in MCH-R1+/+ mice. We report for the first time that animals with genetically inactivated MCH signaling exhibit altered vigilance state architecture and sleep homeostasis. This study also suggests that the MCH system may modulate central pathways involved in the wake-promoting effect of modafinil.

  8. Structurally colored films with superhydrophobicity and wide viewing angles based on bumpy melanin-like particles

    Science.gov (United States)

    Yi, Bo; Shen, Huifang

    2018-01-01

    Non-iridescent structural colors and lotus effect universally existing in the nature provide a great inspiration for artificially developing angle-independent and high hydrophobic structurally colored films. To this end, a facile strategy is put forward for achieving superhydrophobic structurally colored films with wide viewing angles and high visibility based on bumpy melanin-like polydopamine-coated polystyrene particles. Here, hierarchical and amorphous structures are assembled in a self-driven manner due to particles' protrusive surfaces. The superhydrophobicity of the structurally colored films, with water contact angle up to 151°, is realized by combining the hierarchical surface roughness with a dip-coating process of polydimethylsiloxane-hexane solution, while angle-independence revealed in the films is ascribed to amorphous arrays. In addition, benefited from an essential light-absorbing property and high refractive index of polydopamine, the visibility of as-prepared colored films is fundamentally enhanced. Moreover, the mechanical robustness of the films is considerably boosted by inletting 3-aminopropyltriethoxysilane. This fabrication strategy might provide an opportunity for promoting the open-air application of structurally colored coatings.

  9. Structure Characterization and Lead Detoxification Effect of Carboxymethylated Melanin Derived from Lachnum Sp.

    Science.gov (United States)

    Zong, Shuai; Li, Lan; Li, Jinglei; Shaikh, Farnaz; Yang, Liu; Ye, Ming

    2017-06-01

    In the present study, an intracellular melanin, named LIM205, was separated from Lachnum YM205 mycelia and was purified on a Sephadex G-15 column. The molecular weight of LIM205 was determined as 522 Da, and its molecular formula was speculated as C 28 H 14 N 2 O 7 S. The possible chemical structure of LIM205 was determined according to the results of Fourier transform infrared (FT-IR), 1 H NMR, 13 C NMR, and pyrolysis/GC-MS analysis. With the aim to increase its water solubility, its carboxymethylated derivative, named CLIM205, was formed by the substitution of hydrogen atoms in LIM205 with one, two, and three carboxymethylate groups. FT-IR, UV, and ESI-MS analysis demonstrated that the carboxymethylate groups were conjugated onto LIM205. The lead detoxification activities of LIM205 and CLIM205 had also been investigated. In vivo test showed that both LIM205 and CLIM205 reduced the tissue lead concentration, enhanced lead excretion, and reversed lead-induced alterations in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) concentrations in mice, with CLIM205 showed better efficacy. The study indicates that LIM205 and CLIM205 have significant lead detoxification effect which will contribute to solve related problems.

  10. Neurons Containing Orexin or Melanin Concentrating Hormone Reciprocally Regulate Wake and Sleep

    Directory of Open Access Journals (Sweden)

    Roda Rani eKonadhode

    2015-01-01

    Full Text Available There is considerable amount of data on arousal neurons whereas there is a paucity of knowledge regarding neurons that make us fall asleep. Indeed, current network models of sleep-wake regulation list many arousal neuronal populations compared to only one sleep group located in the preoptic area. There are neurons outside the preoptic area that are active during sleep, but they have never been selectively manipulated. Indeed, none of the sleep-active neurons have been selectively stimulated. To close this knowledge gap we used optogenetics to selectively manipulate neurons containing melanin concentrating hormone (MCH. The MCH neurons are located in the posterior hypothalamus intermingled with the orexin arousal neurons. Our data indicated that optogenetic stimulation of MCH neurons in wildtype mice (J Neuroscience, 2013 robustly increased both non-REM and REM sleep. MCH neuron stimulation increased sleep during the animal’s normal active period, which is compelling evidence that stimulation of MCH neurons has a powerful effect in counteracting the strong arousal signal from all of the arousal neurons. The MCH neurons represent the only group of sleep-active neurons that when selectively stimulated induce sleep. From a translational perspective this is potentially useful in sleep disorders, such as insomnia, where sleep needs to be triggered against a strong arousal drive. Our studies indicate that the MCH neurons belong within an overall model of sleep-wake regulation.

  11. Methylquercetins stimulate melanin biosynthesis in a three-dimensional skin model.

    Science.gov (United States)

    Yamauchi, Kosei; Mitsunaga, Tohru

    2018-02-13

    In a previous study, we found that both synthetic 3-O-methylquercetin (3MQ) and 3,4',7-O-trimethylquercetin (34'7TMQ) increased extracellular melanin content. 34'7TMQ increased the activity of melanogenic enzymes by stimulating the p38 pathway and the expression of microphthalmia-associated transcription factor (MITF). In contrast, 3MQ increased the activity of melanogenic enzymes without the involvement of MITF, which suggests that 3MQ inhibits the degradation of melanogenic enzymes. In the present study, we investigated the effects of 3MQ and 34'7TMQ on melanogenesis in normal human melanocytes and using a commercial three-dimensional (3D) skin model system. Both 3MQ and 34'7TMQ elongated the dendrites of normal human melanocytes from a Caucasian donor, but did not stimulate melanogenesis in the melanocytes. In the 3D skin model, which included melanocytes from an Asian donor, 3MQ and 34'7TMQ increased and elongated the melanocytes and showed a tendency to stimulate melanogenesis. These results suggest that 3MQ and 34'7TMQ could be put to practical use in skin care products and agents aimed at preventing hair graying.

  12. Internal dosimetry through GATE simulations of preclinical radiotherapy using a melanin-targeting ligand

    Science.gov (United States)

    Perrot, Y.; Degoul, F.; Auzeloux, P.; Bonnet, M.; Cachin, F.; Chezal, J. M.; Donnarieix, D.; Labarre, P.; Moins, N.; Papon, J.; Rbah-Vidal, L.; Vidal, A.; Miot-Noirault, E.; Maigne, L.

    2014-05-01

    The GATE Monte Carlo simulation platform based on the Geant4 toolkit is under constant improvement for dosimetric calculations. In this study, we explore its use for the dosimetry of the preclinical targeted radiotherapy of melanoma using a new specific melanin-targeting radiotracer labeled with iodine 131. Calculated absorbed fractions and S values for spheres and murine models (digital and CT-scan-based mouse phantoms) are compared between GATE and EGSnrc Monte Carlo codes considering monoenergetic electrons and the detailed energy spectrum of iodine 131. The behavior of Geant4 standard and low energy models is also tested. Following the different authors’ guidelines concerning the parameterization of electron physics models, this study demonstrates an agreement of 1.2% and 1.5% with EGSnrc, respectively, for the calculation of S values for small spheres and mouse phantoms. S values calculated with GATE are then used to compute the dose distribution in organs of interest using the activity distribution in mouse phantoms. This study gives the dosimetric data required for the translation of the new treatment to the clinic.

  13. To compare the gingival melanin repigmentation after diode laser application and surgical removal

    Directory of Open Access Journals (Sweden)

    Gaurav Mahajan

    2017-01-01

    Full Text Available Aim: The aim of the present study is to compare the gingival melanin repigmentation after diode laser application and surgical removal done by scraping with Kirkland knife. Materials and Methods: This study was a randomized split-mouth study where 10 patients presenting with unattractive, diffuse, dark brown to black gingival discoloration on the facial aspect of the maxillary gingiva were treated by diode laser application and surgical removal and followed up for 3-, 6-, and 9-month intervals. Results: The results showed a statistically significant difference in repigmentation between the groups at the interval of 3 months (P = 0.040, but the difference was statistically not significant at 6 months (P = 0.118 and 9 months (P = 0.146. On surgically treated sites, all cases showed repigmentation of the gingiva, but in laser treated, there were two individuals which did not show repigmentation of the gingiva even at the end of 9-month observation time. Conclusion: The incidence of repigmentation was slightly less in laser-treated sites as compared to surgical depigmentation although the difference was statistically significant only up to 3 months.

  14. Analyzing the Role of Receptor Internalization in the Regulation of Melanin-Concentrating Hormone Signaling

    Directory of Open Access Journals (Sweden)

    Jay I. Moden

    2013-01-01

    Full Text Available The regulation of appetite is complex, though our understanding of the process is improving. The potential role for the melanin-concentrating hormone (MCH signaling pathway in the treatment of obesity is being explored by many. It was hypothesized that internalization of MCH receptors would act to potently desensitize cells to MCH. Despite potent desensitization of ERK signaling by MCH in BHK-570 cells, we were unable to observe MCH-mediated internalization of MCH receptor 1 (MCHR1 by fluorescence microscopy. A more quantitative approach using a cell-based ELISA indicated only 15% of receptors internalized, which is much lower than that reported in the literature. When -arrestins were overexpressed in our system, removal of receptors from the cell surface was facilitated and signaling to a leptin promoter was diminished, suggesting that internalization of MCHR1 is sensitive to cellular -arrestin levels. A dominant-negative GRK construct completely inhibited loss of receptors from the cell surface in response to MCH, suggesting that the internalization observed is phosphorylation-dependent. Since desensitization of MCH-mediated ERK signaling did not correlate with significant loss of MCHR1 from the cell surface, we hypothesize that in this model system regulation of MCH signaling may be the result of segregation of receptors from signaling components at the plasma membrane.

  15. Evaluation of the Active Targeting of Melanin Granules after Intravenous Injection of Dendronized Nanoparticles.

    Science.gov (United States)

    Bordeianu, C; Parat, A; Piant, S; Walter, A; Zbaraszczuk-Affolter, C; Meyer, F; Begin-Colin, S; Boutry, S; Muller, R N; Jouberton, E; Chezal, J-M; Labeille, B; Cinotti, E; Perrot, J-L; Miot-Noirault, E; Laurent, S; Felder-Flesch, D

    2018-02-05

    The biodistribution of dendronized iron oxides, NPs10@D1_DOTAGA and melanin-targeting NPs10@D1_ICF_DOTAGA, was studied in vivo using magnetic resonance imaging (MRI) and planar scintigraphy through [ 177 Lu]Lu-radiolabeling. MRI experiments showed high contrast power of both dendronized nanoparticles (DPs) and hepatobiliary and urinary excretions. Little tumor uptake could be highlighted after intravenous injection probably as a consequence of the negatively charged DOTAGA-derivatized shell, which reduces the diffusion across the cells' membrane. Planar scintigraphy images demonstrated a moderate specific tumor uptake of melanoma-targeted [ 177 Lu]Lu-NPs10@D1_ICF_DOTAGA at 2 h post-intravenous injection (pi), and the highest tumor uptake of the control probe [ 177 Lu]Lu-NPs10@D1_DOTAGA at 30 min pi, probably due to the enhanced permeability and retention effect. In addition, ex vivo confocal microscopy studies showed a high specific targeting of human melanoma samples impregnated with NPs10@D1_ICF_Alexa647_ DOTAGA.

  16. Mechanisms relevant to the enhanced virulence of a dihydroxynaphthalene-melanin metabolically engineered entomopathogen.

    Directory of Open Access Journals (Sweden)

    Min-Nan Tseng

    Full Text Available The entomopathogenic fungus Metarhizium anisopliae MA05-169 is a transformant strain that has been metabolically engineered to express dihydroxynaphthalene-melanin biosynthesis genes. In contrast to the wild type strain, the transformant displays a greater resistance to environmental stress and a higher virulence toward target insect host. However, the underlying mechanisms for these characteristics remain unclear; hence experiments were initiated to explore the possible mechanism(s through physiological and molecular approaches. Although both transformant and wild type strains could infect and share the same insect host range, the former germinated faster and produced more appressoria than the latter, both in vivo and in vitro. The transformant showed a significantly shorter median lethal time (LT50 when infecting the diamondback moth (Plutella xylostella and the striped flea beetle (Phyllotreta striolata, than the wild type. Additionally, the transformant was more tolerant to reactive oxygen species (ROS, produced 40-fold more orthosporin and notably overexpressed the transcripts of the pathogenicity-relevant hydrolytic enzymes (chitinase, protease, and phospholipase genes in vivo. In contrast, appressorium turgor pressure and destruxin A content were slightly decreased compared to the wild type. The transformant's high anti-stress tolerance, its high virulence against five important insect pests (cowpea aphid Aphis craccivora, diamondback moth Pl. xylostella, striped flea beetle Ph. striolata, and silverleaf whitefly Bemisia argentifolii and its capacity to colonize the root system are key properties for its potential bio-control field application.

  17. Novel Neuroprotective Effects of Melanin-Concentrating Hormone in Parkinson's Disease.

    Science.gov (United States)

    Park, Ji-Yeun; Kim, Seung-Nam; Yoo, Junsang; Jang, Jaehwan; Lee, Ahreum; Oh, Ju-Young; Kim, Hongwon; Oh, Seung Tack; Park, Seong-Uk; Kim, Jongpil; Park, Hi-Joon; Jeon, Songhee

    2017-12-01

    Acupuncture has shown the therapeutic effect on various neurodegenerative disorders including Parkinson's disease (PD). While investigating the neuroprotective mechanism of acupuncture, we firstly found the novel function of melanin-concentrating hormone (MCH) as a potent neuroprotective candidate. Here, we explored whether hypothalamic MCH mediates the neuroprotective action of acupuncture. In addition, we aimed at evaluating the neuroprotective effects of MCH and elucidating underlying mechanism in vitro and in vivo PD models. First, we tested whether hypothalamic MCH mediates the neuroprotective effects of acupuncture by challenging MCH-R1 antagonist (i.p.) in mice PD model. We also investigated whether MCH has a beneficial role in dopaminergic neuronal protection in vitro primary midbrain and human neuronal cultures and in vivo MPTP-induced, Pitx3 -/- , and A53T mutant mice PD models. Transcriptomics followed by quantitative PCR and western blot analyses were performed to reveal the neuroprotective mechanism of MCH. We first found that hypothalamic MCH biosynthesis was directly activated by acupuncture treatment and that administration of an MCH-R1 antagonist reverses the neuroprotective effects of acupuncture. A novel finding is that MCH showed a beneficial role in dopaminergic neuron protection via downstream pathways related to neuronal survival. This is the first study to suggest the novel neuroprotective action of MCH as well as the involvement of hypothalamic MCH in the acupuncture effects in PD, which holds great promise for the application of MCH in the therapy of neurodegenerative diseases.

  18. HIV-Associated Oral Mucosal Melanin Hyperpigmentation: A Clinical Study in a South African Population Sample

    Directory of Open Access Journals (Sweden)

    R. Chandran

    2016-01-01

    Full Text Available Objective. The aim of the study was to determine the prevalence of HIV-associated oral mucosal melanin hyperpigmentation (HIV-OMH in a specific population of HIV-seropositive South Africans and to analyse the associations between HIV-OMH clinical features and the demographic and immunological characteristics of the study cohort. Material and Methods. This cross-sectional study included 200 HIV-seropositive Black subjects. The collected data comprised age, gender, CD4+ T cell count, viral load, systemic disease, medications, oral site affected by HIV-OMH, extent (localized or generalized, intensity of the pigmentation (dark or light, and smoking and snuff use. Results. Overall, 18.5% of the study cohort had HIV-OMH. Twenty-two and a half percent had OMH that could not with confidence be attributed to HIV infection, and 59% did not have any OMH. There was a significant but weak association between smoking and the presence of HIV-OMH. Conclusions. The prevalence of HIV-OMH in the study population was 18.5%, the gingiva being the most commonly affected site. It appears that the CD4+ T cell count does not play any role in the biopathology of HIV-OMH.

  19. Development of a sensitive solid-phase radioimmunoassay for melanin-concentrating hormone

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, A.N.; Baumann, J.B.; Girard, J. (Univ. Children' s Hospital, Basel (Switzerland)); Baker, B.I.; Kishida, M. (Univ. of Bath (England))

    1989-01-01

    A two-step solid-phase radioimmunoassay for melanin-concentrating hormone (MCH) was developed for direct determination of the hormone in plasma samples. To this end, synthetic MCH was coupled to bovine thyreoglobulin and the complex was injected into rabbits. Specific antisera of high titer were obtained which did not crossreact with other hormones. The IgGs were chemically linked to immunobeads, an acrylamide/acrylic acid polymer matrix. In the first step, plasma MCH was immunoextracted by incubation of diluted plasma samples with anti-MCH immunobeads. In the second step, the washed polymer was incubated with radioiodinated MCH tracer for titration of non-occupied sites. This procedure made it possible to determine as little as 4 pg MCH per ml of plasma. Application of the radioimmunoassay to plasma levels of black or white background-adapted trout showed a marked difference in circulating MCH: while trout on a black background contained a mean value of 29 {plus minus} 5.6 pg/ml, animals on a white background had 106 {plus minus} 19 pg/ml.

  20. Novel analgesic effects of melanin-concentrating hormone on persistent neuropathic and inflammatory pain in mice.

    Science.gov (United States)

    Jang, Jae-Hwan; Park, Ji-Yeun; Oh, Ju-Young; Bae, Sun-Jeong; Jang, Hyunchul; Jeon, Songhee; Kim, Jongpil; Park, Hi-Joon

    2018-01-15

    The melanin-concentrating hormone (MCH) is a peptidergic neuromodulator synthesized by neurons in the lateral hypothalamus and zona incerta. MCHergic neurons project throughout the central nervous system, indicating the involvements of many physiological functions, but the role in pain has yet to be determined. In this study, we found that pMCH -/- mice showed lower baseline pain thresholds to mechanical and thermal stimuli than did pMCH +/+ mice, and the time to reach the maximum hyperalgesic response was also significantly earlier in both inflammatory and neuropathic pain. To examine its pharmacological properties, MCH was administered intranasally into mice, and results indicated that MCH treatment significantly increased mechanical and thermal pain thresholds in both pain models. Antagonist challenges with naltrexone (opioid receptor antagonist) and AM251 (cannabinoid 1 receptor antagonist) reversed the analgesic effects of MCH in both pain models, suggesting the involvement of opioid and cannabinoid systems. MCH treatment also increased the expression and activation of CB1R in the medial prefrontal cortex and dorsolateral- and ventrolateral periaqueductal grey. The MCH1R antagonist abolished the effects induced by MCH. This is the first study to suggest novel analgesic actions of MCH, which holds great promise for the application of MCH in the therapy of pain-related diseases.

  1. Sub-cellular organization of the melanin-concentrating hormone neurons in the hypothalamus.

    Science.gov (United States)

    Jancsik, Veronika; Bene, Roland; Sótonyi, Péter; Zachar, Gergely

    2018-01-01

    Melanin-concentrating hormone (MCH) is a potent orexigenic and sleep-promoting neuropeptide in mammals produced predominately by hypothalamic neurons which project to a wide variety of brain areas. Several MCH producing neurons contain MCH as the only neuropeptide, while others comprise cocaine- and amphetamine regulated transcript (CART) as well. The intrahypothalamic localization and the projection pattern of these two subpopulations are distinct. To provide structural grounding to understand the mechanism of action of MCH neurons we show here the subcellular localization of the neuropeptides in the two subpopulations within the hypothalamus of healthy young male mice by applying single and double immunofluorescence labelling.; Thick, prominent MCH immunopositive reticulation and fine discrete granules are detected within the perikarya of both CART positive and CART-free MCH neurons. Typically, one or more immunoreactive processes emanate from the perikarya. The bulk of CART immunoreactivity is also centrally positioned, surrounded by sparse immunoreactive granules within the perikarya and in the processes. In double immunopositive neurons, the two neuropeptides seem to colocalize in the heavily labelled central area, while the immunopositive granules in the cell body periphery and in the processes apparently contain either MCH or CART. This spatial arrangement suggests that MCH and CART, after being synthetized and processed in the endoplasmic reticulum/Golgi complex, are sorted into separate dense core vesicles, which then enter into the cell processes. This mechanism allows for both concerted and independent regulation of the transport and release of MCH and CART. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Melanin-concentrating hormone: unique peptide neuronal systems in the rat brain and pituitary gland

    Energy Technology Data Exchange (ETDEWEB)

    Zamir, N.; Skofitsch, G.; Bannon, M.J.; Jacobowitz, D.M.

    1986-03-01

    A unique neuronal system was detected in the rat central nervous system by immunohistochemistry and radioimmunoassay with antibodies to salmon melanin-concentrating hormone (MCH). MCH-like immunoreactive (MCH-LI) cell bodies were confined to the hypothalamus. MCH-LI fibers were found throughout the brain but were most prevalent in hypothalamus, mesencephalon, and pons-medulla regions. High concentrations of MCH-LI were measured in the hypothalamic medial forebrain bundle (MFB), posterior hypothalamic nucleus, and nucleus of the diagonal band. Reversed-phase high-performance liquid chromatography of MFB extracts from rat brain indicate that MCH-like peptide from the rat has a different retention time than that of the salmon MCH. An osmotic stimuls (2% NaCl as drinking water for 120 hr) caused a marked increase in MCH-LI concentrations in the lateral hypothalamus and neurointermediate lobe. The present studies establish the presence of MCH-like peptide in the rat brain. The MCH-LI neuronal system is well situated to coordinate complex functions such as regulation of water intake.

  3. A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep

    Directory of Open Access Journals (Sweden)

    Salin Paul

    2003-09-01

    Full Text Available Abstract Background Peptidergic neurons containing the melanin-concentrating hormone (MCH and the hypocretins (or orexins are intermingled in the zona incerta, perifornical nucleus and lateral hypothalamic area. Both types of neurons have been implicated in the integrated regulation of energy homeostasis and body weight. Hypocretin neurons have also been involved in sleep-wake regulation and narcolepsy. We therefore sought to determine whether hypocretin and MCH neurons express Fos in association with enhanced paradoxical sleep (PS or REM sleep during the rebound following PS deprivation. Next, we compared the effect of MCH and NaCl intracerebroventricular (ICV administrations on sleep stage quantities to further determine whether MCH neurons play an active role in PS regulation. Results Here we show that the MCH but not the hypocretin neurons are strongly active during PS, evidenced through combined hypocretin, MCH, and Fos immunostainings in three groups of rats (PS Control, PS Deprived and PS Recovery rats. Further, we show that ICV administration of MCH induces a dose-dependant increase in PS (up to 200% and slow wave sleep (up to 70% quantities. Conclusion These results indicate that MCH is a powerful hypnogenic factor. MCH neurons might play a key role in the state of PS via their widespread projections in the central nervous system.

  4. A UV-Independent Topical Small-Molecule Approach for Melanin Production in Human Skin

    Directory of Open Access Journals (Sweden)

    Nisma Mujahid

    2017-06-01

    Full Text Available The presence of dark melanin (eumelanin within human epidermis represents one of the strongest predictors of low skin cancer risk. Topical rescue of eumelanin synthesis, previously achieved in “redhaired” Mc1r-deficient mice, demonstrated significant protection against UV damage. However, application of a topical strategy for human skin pigmentation has not been achieved, largely due to the greater barrier function of human epidermis. Salt-inducible kinase (SIK has been demonstrated to regulate MITF, the master regulator of pigment gene expression, through its effects on CRTC and CREB activity. Here, we describe the development of small-molecule SIK inhibitors that were optimized for human skin penetration, resulting in MITF upregulation and induction of melanogenesis. When topically applied, pigment production was induced in Mc1r-deficient mice and normal human skin. These findings demonstrate a realistic pathway toward UV-independent topical modulation of human skin pigmentation, potentially impacting UV protection and skin cancer risk.

  5. Deletion of Melanin Concentrating Hormone Receptor-1 disrupts overeating in the presence of food cues.

    Science.gov (United States)

    Sherwood, Andrew; Holland, Peter C; Adamantidis, Antoine; Johnson, Alexander W

    2015-12-01

    Exposure to environmental cues associated with food can evoke eating behavior in the absence of hunger. This capacity for reward cues to promote feeding behaviors under sated conditions can be examined in the laboratory using cue-potentiated feeding (CPF). The orexigenic neuropeptide Melanin Concentrating Hormone (MCH) is expressed throughout brain circuitry critical for CPF. We examined whether deletion of the MCH receptor, MCH-1R, would in KO mice disrupt overeating in the presence of a Pavlovian CS+ associated with sucrose delivery. While both wild-type controls and KO mice showed comparable food magazine approach responses during the CPF test, MCH-1R deletion significantly impaired the ability of the CS+ to evoke overeating of sucrose under satiety. Through the use of a refined analysis of meal intake, it was revealed that this disruption to overeating behavior in KO mice reflected a reduction in the capacity for the CS+ to initiate and maintain bursts of licking behavior. These findings suggest that overeating during CPF requires intact MCH-1R signaling and may be due to an influence of the CS+ on the palatability of food and on regulatory mechanisms of peripheral control. Thus, disruptions to MCH-1R signaling may be a useful pharmacological tool to inhibit this form of overeating behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Utility of sun-reactive skin typing and melanin index for discerning vitamin D deficiency.

    Science.gov (United States)

    Khalid, Arshad T; Moore, Charity G; Hall, Christopher; Olabopo, Flora; Rozario, Nigel L; Holick, Michael F; Greenspan, Susan L; Rajakumar, Kumaravel

    2017-09-01

    BackgroundSkin color, a vitamin D status determinant, can be assessed subjectively by Fitzpatrick sun-reactive skin typing (FST) and objectively by melanin index (MI). FST was validated against MI for discerning vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) serum 25(OH)D in healthy, 8- to 18-year-old children from one of two vitamin D trials. MI from forehead, hand, and upper arm split at the median of the more racially balanced study cohort and FST (I-III vs. IV-V) were used for discriminating vitamin D deficiency.ResultsA total of 296 participants (mean age, 12.3±2.3 years; black, 208; FST IV-V, 209; 25(OH)D Serum 25(OH)D was negatively associated with MI and FST. Sensitivity, specificity, and predictive values were similar for discriminating vitamin D deficiency between higher vs. lower MI and between FST I-III vs. IV-V. ROC area under the curves for FST (0.59) and MI (forehead (0.63); hand (0.62); and arm (0.64)) were similar.ConclusionsFST is comparable to MI for discerning vitamin D deficiency and can be deemed as an inexpensive, useful surrogate measure of skin color in the context of vitamin D research.

  7. Melanin-gamma rays assistants for bismuth oxide nanoparticles synthesis at room temperature for enhancing antimicrobial, and photocatalytic activity.

    Science.gov (United States)

    El-Batal, Ahmed I; El-Sayyad, Gharieb S; El-Ghamry, Abbas; Agaypi, Kerolos M; Elsayed, Mohamed A; Gobara, Mohamed

    2017-08-01

    Melanin pigment has been deemed as a natural photoprotector with strong hydrophobicity. It allured considerable compatibility with many applications in medicine, food, and nanotechnology. Penicillium chrysogenium has been devoted to the green synthesis of melanin whereby optimizing its culture and environmental conditions. The impacts of alternative economic L-tyrosine natural sources (unprecedented alternate origins) and gamma radiation were pledged for the potential growing of the pigment. Herein, notable increases in melanin yield (6.4mg/ml; much higher than nonoptimized one by 40 folds) was obtained by optimizing the culture, and environmental requirements [potato starch (3.0%), yeast extract (5.0%), copper sulfate (0.2mM), 0.25% L-tyrosine, 0.1% L-glycine, and 0.1% Tween 20 at pH5.0, and 30°C for 7.0days using 180.0rpm shaking speed]. The addition of banana's peel (2.0%) has been led to increase the melanin production up to (8.3mg/ml; much higher than optimized one by 1.29 folds). It stimulated the induced enzymes, (i.e., tyrosinase) because it contained significant amounts of L-tyrosine, dopamine, and L-DOPA as resources for melanin biosynthesis. Then irradiated P. chrysogenium (2.5kGy) induced the pigment yield to 10.3mg/ml; much higher than optimized one by (1.61 folds). On the other hand, we tailored a methodology involved the product of melanin and gamma rays (25.0kGy) to an eco-friendly synthesis of Bismuth oxide nanoparticles (BiONPs) at the room temperature. Melanin under such alkaline condition functioning as simultaneously hydrolyzes, photoprotection of the Bi seeds, and stabilizer against the uncontrolled growth and the free radicals attack. Whereas the gamma irradiation induced the room temperature condensation reaction to occur, a novel mechanism proposal was discussed. BiONPs were characterized by UV-Vis., DLS, XRD, SEM, EDX, and FTIR. DLS and XRD calculations with TEM analysis exhibited the mean diameter of BiONPs was 29.82nm. Moreover, the as

  8. Autoradiography of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP): Uptake in the monoaminergic pathways and in melanin containing tissues

    Energy Technology Data Exchange (ETDEWEB)

    Lyden, A.; Lindquist, N.G.; Bondesson, U.; Larsson, B.S.; Olsson, L.-I.

    1985-01-01

    A recently discovered neurotoxic compound, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, has been found to cause a parkinsonian-like syndrome in man and monkey, but not in laboratory animals such as rat, mouse and guinea pig. MPTP seems to selectively destroy the melanin containing dopaminergic cells in pars compacta of substantia nigra. Lower mammalian species do not have melanin in these cells, which indicates that the presence of neuromelanin may be of importance for the development of MPTP-induced lesions. By means of whole-body autoradiography of TH-MPTP in mice, accumulation and retention was observed in the dopaminergic pathways, in locus ceruleus and in structures in the medulla oblongata and spinal cord. A high uptake was also seen in melanin-containing tissues such as in the eyes of pigmented mice. MPTP has earlier been found to have high affinity in vitro for dopamine melanin, which is similar to the pigment in substantia nigra. The typical features of the MPTP-induced neurotoxicity with destruction of pigmented nerve cells and development of parkinsonism may be due to accumulation adn retention of MPTP and its metabolites in these cells. In species with pigmented nerve cells, such as man and monkey, the accumulation may be much more pronounced because of the melanin affinity of MPTP and its metabolites. (author).

  9. Accumulation of 14C-5,6-dihydroxytryptamine-melanin in intrathecal and subependymal phagocytes of the rat CNS and possible routes of their elimination from brain

    Energy Technology Data Exchange (ETDEWEB)

    Baumgarten, H.G.; Moritz, F.; Schlossberger, H.G.

    1981-01-01

    14C-5,6-DHT-Melanin, a labelled synthetic polymer resembling the naturally occurring melanin formed in brain by autoxidation of dopamine, was injected into the left lateral ventricle of adult rats, and its fate followed by autoradiography and by transmission electron microscopy of structures identified as labelled in preceding light micrographs, and by EM-autoradiography. Shortly after injection, melanin particles (easily identified in the em because of their size, structure and electron opacity) were seen ingested by supraependymal and epiplexus cells, by cells residing in the piaarachnoid, i.e. free subarachnoidal cells and perivascular cells, and by subependymally located microglia-like cells with intraventricular processes. Up to day four, an increase in the number of labelled phagocytes in the CSF was noted which transformed into typical reactive macrophages. Beyond this time, many intraventricular melanin-loaded phagocytes formed rounded clusters; cells of such clusters were subsequently found to invade the brain parenchyma by penetrating the ependymal lining and to accumulate in the perivascular space of brain vessels. 14C-Melanin-storing macrophages were found in the marginal sinus of the deep jugular lymph nodes suggesting emigration of CNS-derived phagocytes via lymphatics or prelymphatics that contact the subarachnoidal space compartment. This does not exclude the possibility that some of the macrophages leave the brain via the systemic circulation by penetrating the vascular endothelium; these may be disposed of in peripheral organs other than the lymph nodes.

  10. Neurochemical characterization of neurons expressing melanin-concentrating hormone receptor 1 in the mouse hypothalamus1

    Science.gov (United States)

    Chee, Melissa J. S.; Pissios, Pavlos; Maratos-Flier, Eleftheria

    2013-01-01

    Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that acts via MCH receptor 1 (MCHR1) in the mouse. It promotes positive energy balance thus mice lacking MCH or MCHR1 are lean, hyperactive, and resistant to diet-induced obesity. Identifying the cellular targets of MCH is an important step to understanding the mechanisms underlying MCH actions. We generated the Mchr1-cre mouse that expressed cre recombinase driven by the MCHR1 promoter and crossed it with a tdTomato reporter mouse. The resulting Mchr1-cre/tdTomato progeny expressed easily detectable tdTomato fluorescence in MCHR1 neurons, which were found throughout the olfactory system, striatum, and hypothalamus. To chemically identify MCH-targeted cell populations that play a role in energy balance, MCHR1 hypothalamic neurons were characterized by colabeling select hypothalamic neuropeptides with tdTomato fluorescence. TdTomato fluorescence colocalized with dynorphin, oxytocin, vasopressin, enkephalin, thyrothropin-releasing hormone, and corticotropin-releasing factor immunoreactive cells in the paraventricular nucleus. In the lateral hypothalamus, neurotensin but neither orexin nor MCH neurons expressed tdTomato. In the arcuate nucleus, both Neuropeptide Y and proopiomelanocortin cells expressed tdTomato. We further demonstrated that some of these arcuate neurons were also targets of leptin action. Interestingly, MCHR1 was expressed in the vast majority of leptin-sensitive proopiomelanocortin neurons, highlighting their importance for the orexigenic actions of MCH. Taken together, this study supports the use of the Mchr1-cre mouse for outlining the neuroanatomical distribution and neurochemical phenotype of MCHR1 neurons. PMID:23605441

  11. Intestinal upregulation of melanin-concentrating hormone in TNBS-induced enterocolitis in adult zebrafish.

    Directory of Open Access Journals (Sweden)

    Brenda M Geiger

    Full Text Available BACKGROUND: Melanin-concentrating hormone (MCH, an evolutionarily conserved appetite-regulating neuropeptide, has been recently implicated in the pathogenesis of inflammatory bowel disease (IBD. Expression of MCH is upregulated in inflamed intestinal mucosa in humans with colitis and MCH-deficient mice treated with trinitrobenzene-sulfonic acid (TNBS develop an attenuated form of colitis compared to wild type animals. Zebrafish have emerged as a new animal model of IBD, although the majority of the reported studies concern zebrafish larvae. Regulation MCH expression in the adult zebrafish intestine remains unknown. METHODS: In the present study we induced enterocolitis in adult zebrafish by intrarectal administration of TNBS. Follow-up included survival analysis, histological assessment of changes in intestinal architecture, and assessment of intestinal infiltration by myeloperoxidase positive cells and cytokine transcript levels. RESULTS: Treatment with TNBS dose-dependently reduced fish survival. This response required the presence of an intact microbiome, since fish pre-treated with vancomycin developed less severe enterocolitis. At 6 hours post-challenge, we detected a significant influx of myeloperoxidase positive cells in the intestine and upregulation of both proinflammatory and anti-inflammatory cytokines. Most importantly, and in analogy to human IBD and TNBS-induced mouse experimental colitis, we found increased intestinal expression of MCH and its receptor in TNBS-treated zebrafish. CONCLUSIONS: Taken together these findings not only establish a model of chemically-induced experimental enterocolitis in adult zebrafish, but point to effects of MCH in intestinal inflammation that are conserved across species.

  12. Ultrastructure: effects of melanin pigment on target specificity using a pulsed dye laser (577 nm)

    Energy Technology Data Exchange (ETDEWEB)

    Tong, A.K.; Tan, O.T.; Boll, J.; Parrish, J.A.; Murphy, G.F.

    1987-06-01

    It has been shown recently that brief pulses of 577 nm radiation from the tunable dye laser are absorbed selectively by oxyhemoglobin. This absorption is associated with highly specific damage to superficial vascular plexus blood vessels in those with lightly pigmented (type I-II) skin. To determine whether pigmentary differences in the overlying epidermis influence this target specificity, we exposed both type I (fair) and type V (dark) normal human skin to varying radiant exposure doses over 1.5-microsecond pulse durations from the tunable dye laser at a wavelength of 577 nm. Using ultrastructural techniques, we found in type I skin that even clinical subthreshold laser exposures caused reproducible alterations of erythrocytes and adjacent dermal vascular endothelium without comparable damage to the overlying epidermis. In contrast, degenerated epidermal basal cells represented the predominant form of cellular damage after laser exposure of type V skin at comparable doses. We conclude that epidermal melanin and vascular hemoglobin are competing sites for 577 nm laser absorption and damage, and that the target specificity of the 577 nm tunable dye laser is therefore influenced by variations in epidermal pigmentation. This finding is relevant to the clinical application of the tunable dye laser in the ablative treatment of vascular lesions. We also found on ultrastructure that the presence of electron-lucent circular structures of approximately 800 A in diameter were observed only at and above clinical threshold doses in those with type I skin and at the highest dose of 2.75 J/cm2 in type V skin. It has been proposed that these structures might be heat-fixed molds of water vapor. Both this and ultrastructural changes of epidermal basal cells demonstrate mechanisms responsible for alteration of tissue after exposure to 577 nm, which are discussed.

  13. The melanin-concentrating hormone (MCH system modulates behaviors associated with psychiatric disorders.

    Directory of Open Access Journals (Sweden)

    Shinjae Chung

    Full Text Available Deficits in sensorimotor gating measured by prepulse inhibition (PPI of the startle have been known as characteristics of patients with schizophrenia and related neuropsychiatric disorders. PPI disruption is thought to rely on the activity of the mesocorticolimbic dopaminergic system and is inhibited by most antipsychotic drugs. These drugs however act also at the nigrostriatal dopaminergic pathway and exert adverse locomotor responses. Finding a way to inhibit the mesocorticolimbic- without affecting the nigrostriatal-dopaminergic pathway may thus be beneficial to antipsychotic therapies. The melanin-concentrating hormone (MCH system has been shown to modulate dopamine-related responses. Its receptor (MCH1R is expressed at high levels in the mesocorticolimbic and not in the nigrostriatal dopaminergic pathways. Interestingly a genomic linkage study revealed significant associations between schizophrenia and markers located in the MCH1R gene locus. We hypothesize that the MCH system can selectively modulate the behavior associated with the mesocorticolimbic dopamine pathway. Using mice, we found that central administration of MCH potentiates apomorphine-induced PPI deficits. Using congenic rat lines that differ in their responses to PPI, we found that the rats that are susceptible to apomorphine (APO-SUS rats and exhibit PPI deficits display higher MCH mRNA expression in the lateral hypothalamic region and that blocking the MCH system reverses their PPI deficits. On the other hand, in mice and rats, activation or inactivation of the MCH system does not affect stereotyped behaviors, dopamine-related responses that depend on the activity of the nigrostriatal pathway. Furthermore MCH does not affect dizocilpine-induced PPI deficit, a glutamate related response. Thus, our data present the MCH system as a regulator of sensorimotor gating, and provide a new rationale to understand the etiologies of schizophrenia and related psychiatric disorders.

  14. Cytoskeleton-related regulation of primary cilia shortening mediated by melanin-concentrating hormone receptor 1.

    Science.gov (United States)

    Tomoshige, Sakura; Kobayashi, Yuki; Hosoba, Kosuke; Hamamoto, Akie; Miyamoto, Tatsuo; Saito, Yumiko

    2017-11-01

    Primary cilia are specialized microtubule-based organelles. Their importance is highlighted by the gamut of ciliary diseases associated with various syndromes including diabetes and obesity. Primary cilia serve as signaling hubs through selective interactions with ion channels and conventional G-protein-coupled receptors (GPCRs). Melanin-concentrating hormone (MCH) receptor 1 (MCHR1), a key regulator of feeding, is selectively expressed in neuronal primary cilia in distinct regions of the mouse brain. We previously found that MCH acts on ciliary MCHR1 and induces cilia shortening through a Gi/o-dependent Akt pathway with no cell cycle progression. Many factors can participate in cilia length control. However, the mechanisms for how these molecules are relocated and coordinated to activate cilia shortening are poorly understood. In the present study, we investigated the role of cytoskeletal dynamics in regulating MCH-induced cilia shortening using clonal MCHR1-expressing hTERT-RPE1 cells. Pharmacological and biochemical approaches showed that cilia shortening mediated by MCH was associated with increased soluble cytosolic tubulin without changing the total tubulin amount. Enhanced F-actin fiber intensity was also observed in MCH-treated cells. The actions of various pharmacological agents revealed that coordinated actin machinery, especially actin polymerization, was required for MCHR1-mediated cilia shortening. A recent report indicated the existence of actin-regulated machinery for cilia shortening through GPCR agonist-dependent ectosome release. However, our live-cell imaging experiments showed that MCH progressively elicited cilia shortening without exclusion of fluorescence-positive material from the tip. Short cilia phenotypes have been associated with various metabolic disorders. Thus, the present findings may contribute toward better understanding of how the cytoskeleton is involved in the GPCR ligand-triggered cilia shortening with cell mechanical

  15. The Melanin-Concentrating Hormone as an Integrative Peptide Driving Motivated Behaviors

    Directory of Open Access Journals (Sweden)

    Giovanne B. Diniz

    2017-05-01

    Full Text Available The melanin-concentrating hormone (MCH is an important peptide implicated in the control of motivated behaviors. History, however, made this peptide first known for its participation in the control of skin pigmentation, from which its name derives. In addition to this peripheral role, MCH is strongly implicated in motivated behaviors, such as feeding, drinking, mating and, more recently, maternal behavior. It is suggested that MCH acts as an integrative peptide, converging sensory information and contributing to a general arousal of the organism. In this review, we will discuss the various aspects of energy homeostasis to which MCH has been associated to, focusing on the different inputs that feed the MCH peptidergic system with information regarding the homeostatic status of the organism and the exogenous sensory information that drives this system, as well as the outputs that allow MCH to act over a wide range of homeostatic and behavioral controls, highlighting the available morphological and hodological aspects that underlie these integrative actions. Besides the well-described role of MCH in feeding behavior, a prime example of hypothalamic-mediated integration, we will also examine those functions in which the participation of MCH has not yet been extensively characterized, including sexual, maternal, and defensive behaviors. We also evaluated the available data on the distribution of MCH and its function in the context of animals in their natural environment. Finally, we briefly comment on the evidence for MCH acting as a coordinator between different modalities of motivated behaviors, highlighting the most pressing open questions that are open for investigations and that could provide us with important insights about hypothalamic-dependent homeostatic integration.

  16. Dynamic thermal effects of epidermal melanin and plasmonic nanoparticles during photoacoustic breast imaging

    Science.gov (United States)

    Ghassemi, Pejhman; Wang, Quanzeng; Pfefer, T. Joshua

    2016-03-01

    Photoacoustic Tomography (PAT) employs high-power near-infrared (near-IR) laser pulses to generate structural and functional information on tissue chromophores up to several centimeters below the surface. Such insights may facilitate detection of breast cancer - the most common cancer in women. PAT mammography has been the subject of extensive research, including techniques based on exogenous agents for PAT contrast enhancement and molecular specificity. However, photothermal safety risks of PAT due to strong chromophores such as epidermal melanin and plasmonic nanoparticles have not been rigorously studied. We have used computational and experimental approaches to elucidate highly dynamic optical-thermal processes during PAT. A Monte Carlo model was used to simulate light propagation at 800 and 1064 nm in a multi-layer breast tissue geometry with different epidermal pigmentation levels and a tumorsimulating inclusion incorporating nanoparticles. Energy deposition results were then used in a bioheat transfer model to simulate temperature transients. Experimental measurements involved multi-layer hydrogel phantoms with inclusions incorporating gold nanoparticles. Phantom optical properties were measured using the inverse adding-doubling technique. Thermal imaging was performed as phantoms were irradiated with 5 ns near-IR pulses. Scenarios using 10 Hz laser irradiation of breast tissue containing various nanoparticle concentrations were implemented experimentally and computationally. Laser exposure levels were based on ANSI/IEC limits. Surface temperature measurements were compared to corresponding simulation data. In general, the effect of highly pigmented skin on temperature rise was significant, whereas unexpectedly small levels of temperature rise during nanoparticle irradiation were attributed to rapid photodegradation. Results provide key initial insights into light-tissue interactions impacting the safety and effectiveness of PAT.

  17. Electrophysiological Properties of Melanin-Concentrating Hormone and Orexin Neurons in Adolescent Rats

    Directory of Open Access Journals (Sweden)

    Victoria Linehan

    2018-03-01

    Full Text Available Orexin and melanin-concentrating hormone (MCH neurons have complementary roles in various physiological functions including energy balance and the sleep/wake cycle. in vitro electrophysiological studies investigating these cells typically use post-weaning rodents, corresponding to adolescence. However, it is unclear whether these neurons are functionally mature at this period and whether these studies can be generalized to adult cells. Therefore, we examined the electrophysiological properties of orexin and MCH neurons in brain slices from post-weaning rats and found that MCH neurons undergo an age-dependent reduction in excitability, but not orexin neurons. Specifically, MCH neurons displayed an age-dependent hyperpolarization of the resting membrane potential (RMP, depolarizing shift of the threshold, and decrease in excitatory transmission, which reach the adult level by 7 weeks of age. In contrast, basic properties of orexin neurons were stable from 4 weeks to 14 weeks of age. Furthermore, a robust short-term facilitation of excitatory synapses was found in MCH neurons, which showed age-dependent changes during the post-weaning period. On the other hand, a strong short-term depression was observed in orexin neurons, which was similar throughout the same period. These differences in synaptic responses and age dependence likely differentially affect the network activity within the lateral hypothalamus where these cells co-exist. In summary, our study suggests that orexin neurons are electrophysiologically mature before adolescence whereas MCH neurons continue to develop until late adolescence. These changes in MCH neurons may contribute to growth spurts or consolidation of adult sleep patterns associated with adolescence. Furthermore, these results highlight the importance of considering the age of animals in studies involving MCH neurons.

  18. Melanin-concentrating hormone (MCH: role in REM sleep and depression

    Directory of Open Access Journals (Sweden)

    Pablo eTorterolo

    2015-12-01

    Full Text Available The melanin-concentrating hormone (MCH is a peptidergic neuromodulator synthesized by neurons of the lateral hypothalamus and incerto-hypothalamic area. MCHergic neurons project throughout the central nervous system, including areas such as the dorsal (DR and median (MR raphe nuclei, which are involved in the control of sleep and mood.Major Depression (MD is a prevalent psychiatric disease diagnosed on the basis of symptomatic criteria such as sadness or melancholia, guilt, irritability and anhedonia. A short REM sleep latency (i.e. the interval between sleep onset and the first REM sleep period, as well as an increase in the duration of REM sleep and the density of rapid-eye movements during this state, are considered important biological markers of depression. The fact that the greatest firing rate of MCHergic neurons occurs during REM sleep and that optogenetic stimulation of these neurons induces sleep, tends to indicate that MCH plays a critical role in the generation and maintenance of sleep, especially REM sleep. In addition, the acute microinjection of MCH into the DR promotes REM sleep, while immunoneutralization of this peptide within the DR decreases the time spent in this state. Moreover, microinjections of MCH into either the DR or MR promote a depressive-like behavior. In the DR, this effect is prevented by the systemic administration of antidepressant drugs (either fluoxetine or nortriptyline and blocked by the intra-DR microinjection of a specific MCH receptor antagonist. Using electrophysiological and microdialysis techniques we demonstrated also that MCH decreases the activity of serotonergic DR neurons.Therefore, there are substantive experimental data suggesting that the MCHergic system plays a role in the control of REM sleep and, in addition, in the pathophysiology of depression. Consequently, in the present report, we summarize and evaluate the current data and hypotheses related to the role of MCH in REM sleep and MD.

  19. Quercus infectoria and Terminalia chebula decrease melanin content and tyrosinase activity in B16/F10 cell lines

    Directory of Open Access Journals (Sweden)

    Akram Jamshidzadeh

    2017-10-01

    Full Text Available Context: One of the most complained skin cares in ethnic skin like Asian women is hyperpigmentation, and lightening preparations have been long-standing desired. Due to the side effects of current drugs, medicinal plants have attracted more attentions as a source of novel drugs. Mazo (Quercus infectoria galls and Terminalia chebula fruits have been suggested in Persian Traditional Medicine as a safe treatment for hyperpigmentation. Aims: To evaluate the cytotoxicity and the effect on melanin synthesis in B16/F10 melanoma of Q. infectoria and T. chebula extracts. Methods: After collection and scientific authentication, plants were extracted by maceration method with methanol and were standardized based on total phenolic content. MTT assay and colorimetric method were used for cytotoxicity and determination of melanin content and tyrosinase activity in B16/F10 cells, respectively. Kojic acid was used as a reference compound. Results: Total phenolic content of Q. infectoria and T. chebula was determined as 287.34 ± 4.21 and 172.61 ± 8.67 mg gallic acid equivalent/g dried extract, respectively. Both plants decreased cell viability at 100 µg/mL and significantly reduced intercellular melanin to 66.25% and 71.1%, respectively in comparison to kojic acid (56.63% at 50 µg/mL. In the same concentration, 65.7% and 71.2% tyrosinase activity was inhibited by Q. infectoria and T. chebula, which significantly were different from control (p<0.001. Conclusions: These findings suggest that both plants especially Q. infectoria could inhibit melanogenesis in non-toxic concentrations and would be a good candidate for further studies.

  20. Influence of melanocytes in the ex-vivo reconstructed epidermal melanin unit following an acute UV irradiation

    International Nuclear Information System (INIS)

    Cario-Andre, M.

    2000-11-01

    Influence of melanocytes in skin pigmentation is well documented, however its photo-protective role has given rise to controversy. The role of melanocytes have been investigated on reconstructed epidermis with 100 % of keratinocytes or 95 % of keratinocytes and 5 % of melanocytes. In a first time, the effect of an acute UVB dose has been studied on both reconstructed epidermis, next we have investigated UVA and UVA+B effects on these epidermis. Following irradiation, the presence of melanocytes in reconstructed epidermis protects against apoptosis without protecting significantly against DNA damage formation (CPD, 6-4PP) and protects against UV-induced unbalance of the SOD/catalase ratio (antioxidants enzymes). On the contrary, the presence of melanocytes in reconstructed epidermis amplifies lipids and proteins oxidations but seems to protect against DNA oxidations. Melanocytes differ from keratinocytes by their melanin content and their more important concentration in polyunsaturated fatty acids. To evaluate what is the part of melanin and the part of polyunsaturated fatty acids in epidermal UV responses, reconstructed epidermis with keratinocytes have been supplemented with polyunsaturated fatty acid. This study indicates that polyunsaturated fatty acids are responsible for lipids and proteins oxidations and that melanin protect against DNA oxidation induced by lipid peroxidation. All these studies demonstrate that, model of reconstructed epidermis and epidermis in-vivo have the same behaviour following UV irradiation. In the last part, sunscreens and antioxidants have been tested on reconstructed epidermis and have demonstrated that model of reconstructed epidermis is suitable for photo-protective molecules screening. (author)

  1. Polarization-Sensitive Optical Coherence Tomographic Documentation of Choroidal Melanin Loss in Chronic Vogt-Koyanagi-Harada Disease.

    Science.gov (United States)

    Miura, Masahiro; Makita, Shuichi; Yasuno, Yoshiaki; Tsukahara, Rintaro; Usui, Yoshihiko; Rao, Narsing A; Ikuno, Yasushi; Uematsu, Sato; Agawa, Tetsuya; Iwasaki, Takuya; Goto, Hiroshi

    2017-09-01

    Vogt-Koyanagi-Harada (VKH) disease is a systemic autoimmune disorder that affects organs with melanocytes. The sunset glow fundus (SGF) in VKH disease was evaluated with polarization-sensitive optical coherence tomography (PS-OCT). The study involved 28 eyes from 14 patients with chronic VKH disease, 21 eyes from 21 age-matched controls, and 22 eyes from 22 high-myopic patients with a tessellated fundus. VKH eyes were grouped into sunset or non-sunset groups on the basis of color fundus images. The presence of melanin in the choroid was determined by using the degree of polarization uniformity (DOPU) obtained by PS-OCT. The sunset glow index (SGI) was calculated by using color fundus images. Presence of an SGF was evaluated by using DOPU, SGI, subfoveal choroidal thicknesses, near-infrared images, and autofluorescence images at 488 nm (SW-AF) and 785 nm (NIR-AF). There were 16 eyes in the sunset group and 12 eyes in the non-sunset group. For all eyes in the sunset group, the disappearance of choroidal melanin was clearly detected with PS-OCT. Percentage areas of low DOPU in the choroidal interstitial stroma of the sunset group were significantly lower than those of other groups and showed no overlap with other groups. The distribution of choroidal thicknesses and SGI in the sunset group substantially overlapped with other groups. The subjective analyses of the sunset and non-sunset groups, using near infrared, SW-AF, or NIR-AF, showed substantial inconsistencies with the PS-OCT results. PS-OCT provides an in vivo objective evaluation of choroidal melanin loss of the SGF in chronic VKH disease.

  2. Oxidation levels differentially impact melanocytes: low versus high concentration of hydrogen peroxide promotes melanin synthesis and melanosome transfer.

    Science.gov (United States)

    Tang, Luyan; Li, Jian; Lin, Xiao; Wu, Wenyu; Kang, Kefei; Fu, Wenwen

    2012-01-01

    UVB light can generate potentially harmful hydrogen peroxide (H(2)O(2)) in vivo, but it can also promote the beneficial proliferation and migration of melanocytes. The successful use of UVB monotherapy for treatment of vitiligo suggests that H(2)O(2) may have a biphasic effect on melanin synthesis and melanosome transfer. To study the beneficial role of H(2)O(2) on melanogenesis and melanosome transport in living melanocytes and keratinocytes. A co-culture system model was constructed using the primary human melanocytes and keratinocytes. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine cell proliferation, NaOH was used to determine the melanin content, and real-time PCR was used to determine tyrosinase expression. Western blot was used to determine Rab-27A and protease-activated receptor 2 (PAR-2) expression. This study demonstrated that tyrosinase was activated by low concentrations of H(2)O(2) (≤0.3 mM); however, this activity was downregulated by high concentrations of H(2)O(2) (>0.3 mM). Activation of high levels of melanin synthesis was induced when cells were treated with low concentrations of H(2)O(2) (0.3 mM). Further observation using an in vitro co-culture system of fluorescein (carboxyfluorescein diacetate succinimidyl ester, CFDA-SE)-labeled melanocytes and keratinocytes indicated that melanosome transfer occurred in normal human epidermal melanocytes. Fluorescence microscopy revealed increased melanosome transfer into keratinocytes treated with 0.3 mM H(2)O(2) in the co-culture compared to the control. Examination of melanosomes in the keratinocytes by flow cytometry confirmed these results. Furthermore, treatment with H(2)O(2) (0.3 mM) upregulated the expression of Rab-27A and PAR-2, significant proteins involved in melanosome transfer, according to Western blot. These results confirmed that low concentration levels of H(2)O(2) play a major role in the regulation of human pigmentation by increasing

  3. Effect of x-ray irradiation upon the epithelial melanin unit of the hair bulb in hooded rat

    Energy Technology Data Exchange (ETDEWEB)

    Kostanecki, W.; Radwan, I.; Mroczkowski, T.

    1976-10-27

    A marked increase in the quantity of pigment in the upper bulb, penetration of melanosomes into the papillae and vacuolisation of the bulk keratinocytes occurred as early as 4 to 6 h after irradiation with a dose 600 to 1200 R. Afterwards considerable hyperpigmentations appeared in the proximal segments of dystrophic and catagen hairs and melanin was found in the catagen columns and beyond them. In most animals within 4 to 6 h after irradiation occurred a distinct vacuolisation of the Malpighian layer and the granular layer became more prominent.

  4. Effect of the tyrosinase inhibitor (S)-N-trans-feruloyloctopamine from garlic skin on tyrosinase gene expression and melanine accumulation in melanoma cells.

    Science.gov (United States)

    Wu, Yan; Wu, Zheng-Rong; Chen, Peng; Yang-Li; Deng, Wan-Rong; Wang, You-Quan; Li, Hong-Yu

    2015-04-01

    In our searching for novel tyrosinase inhibitors from natural sources, (S)-N-trans-feruloyloctopamine isolated from garlic skin was found to be a potential mushroom tyrosinase inhibitor. Here, we examined the effects of the potential tyrosinase inhibitor in B16F10 cells on intracellular melanin contents, cytotoxicity, and the signaling mechanism involved in the expression of tyrosinase. The results showed the inhibitor displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin contents in a dose-dependent manner in the α-MSH-stimulated B16F10 cells. Real-time PCR and Western blot analysis showed that it inhibits melanogenesis signaling by down-regulates mRNA and protein expression levels of tyrosinase, which leads to a lower melanin contents. These results suggested that (S)-N-trans-feruloyloctopamine was an ideal tyrosinase inhibitor, and could be used in food and medical industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effects of ultraviolet-visible irradiation in the presence of melanin isolated from human black or red hair upon Ehrlich ascites carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Menon, I.A.; Persad, S.; Ranadive, N.S.; Haberman, H.F.

    1983-07-01

    The present study is an attempt to investigate the possibility that ultraviolet irradiation in the presence of pheomelanin may be more harmful to cells than the irradiation in the presence of eumelanin. The effects of UV-visible irradiation upon Ehrlich ascites carcinoma cells in the presence of the melanin isolated from human black hair (eumelanin) or from red hair (pheomelanin) were investigated. Irradiation of these cells was found to produce cell lysis, as observed by leakage of 51Cr from labeled cells and intracellular lactic dehydrogenase from the cells and decrease in cell viability demonstrated by the trypan blue exclusion test. The three parameters were quantitatively parallel to one another under various experimental conditions, namely different periods of irradiation and irradiation in the presence of different concentrations of melanin. The above effects were more pronounced when the irradiation was carried out in the presence of melanin from red hair than in the presence of black-hair melanin. In the absence of either melanin, the irradiation did not produce any significant effect in cell viability or cell lysis. Irradiation of the cells in the presence of red-hair melanin also decreased the transplantability of these cells. These observations clearly show that irradiation of cells in the presence of pheomelanin could produce cytotoxic effects. The present experimental design may have application in the development of in vitro models for the study of UV radiation-induced cutaneous carcinogenesis. The reactions of pheomelanin may be related to the susceptibility of ''Celtic'' skin to UV radiation-induced skin damage and carcinogenesis.

  6. Estimate of the melanin content in human hairs by the inverse Monte-Carlo method using a system for digital image analysis

    International Nuclear Information System (INIS)

    Bashkatov, A N; Genina, Elina A; Kochubei, V I; Tuchin, Valerii V

    2006-01-01

    Based on the digital image analysis and inverse Monte-Carlo method, the proximate analysis method is deve-loped and the optical properties of hairs of different types are estimated in three spectral ranges corresponding to three colour components. The scattering and absorption properties of hairs are separated for the first time by using the inverse Monte-Carlo method. The content of different types of melanin in hairs is estimated from the absorption coefficient. It is shown that the dominating type of melanin in dark hairs is eumelanin, whereas in light hairs pheomelanin dominates. (special issue devoted to multiple radiation scattering in random media)

  7. Haste makes waste: accelerated molt adversely affects the expression of melanin-based and depigmented plumage ornaments in house sparrows.

    Directory of Open Access Journals (Sweden)

    Csongor I Vágási

    2010-12-01

    Full Text Available Many animals display colorful signals in their integument which convey information about the quality of their bearer. Theoretically, these ornaments incur differential production and/or maintenance costs that enforce their honesty. However, the proximate mechanisms of production costs are poorly understood and contentious in cases of non-carotenoid-based plumage ornaments like the melanin-based badge and depigmented white wing-bar in house sparrows Passer domesticus. Costly life-history events are adaptively separated in time, thus, when reproduction is extended, the time available for molt is curtailed and, in turn, molt rate is accelerated.We experimentally accelerated the molt rate by shortening the photoperiod in order to test whether this environmental constraint is mirrored in the expression of plumage ornaments. Sparrows which had undergone an accelerated molt developed smaller badges and less bright wing-bars compared to conspecifics that molted at a natural rate being held at natural-like photoperiod. There was no difference in the brightness of the badge or the size of the wing-bar.These results indicate that the time available for molt and thus the rate at which molt occurs may constrain the expression of melanin-based and depigmented plumage advertisements. This mechanism may lead to the evolution of honest signaling if the onset of molt is condition-dependent through the timing of and/or trade-off between breeding and molt.

  8. Inhibitory and Acceleratory Effects of Inonotus obliquus on Tyrosinase Activity and Melanin Formation in B16 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Zheng-Fei Yan

    2014-01-01

    Full Text Available The aim of the present study is to preliminarily investigate the antimelanogenesis effect of Inonotus obliquus extracts by cell-free mushroom tyrosinase assay. It was found that petroleum ether and n-butanol extracts might contain unknown potential tyrosinase inhibitors, while its ethyl acetate extract might contain some unknown accelerators. Six compounds were isolated and their structures were identified by interpretation of NMR data and nicotinic acid was first discovered in Inonotus obliquus. In cells testing, betulin and trametenolic acid decreased tyrosinase activity and melanin content, while inotodiol and lanosterol significantly increased tyrosinase activity and melanin content, showing an AC⁡50 of 9.74 and 8.43 μM, respectively. Nicotinie acid, 3β,22,25-trihydroxy-lanosta-8-ene, had a little or no effect on tyrosinase. Betulin exhibited a mode of noncompetitive inhibition with a KI=KIS of 0.4 μM on tyrosinase activity showing an IC50 of 5.13 μM and being more effective than kojic acid (6.43 μM, and trametenolic acid exhibited a mode of mixed inhibition with a KI of 0.9 μM, KIS of 0.5 μM, and an IC50 of 7.25 μM. We proposed betulin and trametenolic acid as a new candidate of potent tyrosinase inhibitors and inotodiol and lanosterol as accelerators that could be used as therapeutic agent.

  9. Identification and Molecular Characterization of the Homogentisate Pathway Responsible for Pyomelanin Production, the Major Melanin Constituents in Aeromonas media WS

    Science.gov (United States)

    Wang, He; Qiao, Yunqian; Chai, Baozhong; Qiu, Chenxi; Chen, Xiangdong

    2015-01-01

    The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine) based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate). Gene products of phhA (encodes phenylalanine hydroxylase), tyrB and aspC (both encode aromatic amino acid aminotransferase), and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase) constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species. PMID:25793756

  10. Melanin-based coloration covaries with ovary size in an age-specific manner in the barn owl

    Science.gov (United States)

    Roulin, Alexandre

    2009-10-01

    While the adaptive function of black eumelanin-based coloration is relatively well known, the function of reddish-brown pheomelanin-based coloration is still unclear. Only a few studies have shown or suggested that the degree of reddish-brownness is associated with predator-prey relationships, reproductive parameters, growth rate and immunity. To gain insight into the physiological correlates of melanin-based coloration, I collected barn owl ( Tyto alba) cadavers and examined the covariation between this colour trait and ovary size, an organ that increases in size before reproduction. A relationship is expected because melanin-based coloration often covaries with sexual activity. The results showed that reddish-brown juveniles had larger ovaries than whiter juveniles particularly in individuals in poor condition and outside the breeding season, while in birds older than 2 years lightly coloured females had larger ovaries than reddish-brown conspecifics. As barn owls become less reddish-brown between the first and second year of age, the present study suggests that reddish-brown pheomelanic and whitish colorations are associated with juvenile- and adult-specific adaptations, respectively.

  11. Retroperitoneal sclerosing PEComa with melanin pigmentation and granulomatous inflammation-A rare association within an uncommon tumor

    Directory of Open Access Journals (Sweden)

    Bharat Rekhi

    2012-01-01

    Full Text Available PEComa, defined as a perivascular epithelioid cell tumor, displays a wide clinicopathological spectrum. Lately, a sclerosing PEComa has been identified as its distinct variant, but with limited documentation, in view of its rarity. Herein, we describe an uncommon case of a 53-year-old lady, who was referred to us with pain abdomen. Radiological imaging disclosed a well-defined, hypodense retroperitoneal mass. The excised tumor was a round, encapsulated soft tissue mass measuring 7 cm with a tan-brown cut surface. Microscopy showed uniform, epithelioid cells with clear cytoplasm, focal melanin pigmentation and mild nuclear atypia, arranged in sheets and nests around capillary-sized vessels in a dense sclerotic stroma. Additionally, co-existing epithelioid granulomas were noted. On immunohistochemistry (IHC, tumor cells were diffusely positive for HMB45; focally for desmin and smooth muscle actin (SMA, while negative for EMA, CD10, S100-P, Melan A, CD34, AMACR and CK MNF116. This case reinforces sclerosing PEComa as an uncommon, but a distinct clinicopathological entity and exemplifies diagnostic challenge associated with it; necessitating application of IHC markers for its correct identification. Presence of melanin pigment and granulomatous inflammation in the present tumor constitute as novel histopathological findings in a sclerosing PEComa.

  12. Identification and molecular characterization of the homogentisate pathway responsible for pyomelanin production, the major melanin constituents in Aeromonas media WS.

    Directory of Open Access Journals (Sweden)

    He Wang

    Full Text Available The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate. Gene products of phhA (encodes phenylalanine hydroxylase, tyrB and aspC (both encode aromatic amino acid aminotransferase, and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.

  13. Can a one-layer optical skin model including melanin and inhomogeneously distributed blood explain spatially resolved diffuse reflectance spectra?

    Science.gov (United States)

    Karlsson, Hanna; Pettersson, Anders; Larsson, Marcus; Strömberg, Tomas

    2011-02-01

    Model based analysis of calibrated diffuse reflectance spectroscopy can be used for determining oxygenation and concentration of skin chromophores. This study aimed at assessing the effect of including melanin in addition to hemoglobin (Hb) as chromophores and compensating for inhomogeneously distributed blood (vessel packaging), in a single-layer skin model. Spectra from four humans were collected during different provocations using a twochannel fiber optic probe with source-detector separations 0.4 and 1.2 mm. Absolute calibrated spectra using data from either a single distance or both distances were analyzed using inverse Monte Carlo for light transport and Levenberg-Marquardt for non-linear fitting. The model fitting was excellent using a single distance. However, the estimated model failed to explain spectra from the other distance. The two-distance model did not fit the data well at either distance. Model fitting was significantly improved including melanin and vessel packaging. The most prominent effect when fitting data from the larger separation compared to the smaller separation was a different light scattering decay with wavelength, while the tissue fraction of Hb and saturation were similar. For modeling spectra at both distances, we propose using either a multi-layer skin model or a more advanced model for the scattering phase function.

  14. RNAi-mediated down-regulation of a melanin polyketide synthase (pks1) gene in the fungus Slafractonia leguminicola.

    Science.gov (United States)

    Alhawatema, Mohammad S; Gebril, Sayed; Cook, Daniel; Creamer, Rebecca

    2017-09-20

    The fungus Slafractonia leguminicola, the causal agent of blackpatch disease of legumes produces two mycotoxins slaframine and swainsonine, causing slobbers' symptoms and locoism of grazing animals, respectively. The genetics of this important fungus is poorly understood. This work aimed to develop a genetic transformation system and evaluate the efficacy of RNA interference (RNAi) in S. leguminicola. In this study, S. leguminicola was transformed using a PEG-mediated method with a fungal construct that carries a hygromycin resistance cassette. To assess the use of RNAi, a silencing construct pSilentPKS1-AS was constructed which includes inverted repeat transgenes of the polyketide synthase gene (pks1) that is involved in melanin biosynthesis. Transformation of S. leguminicola with the IRT pks1 vector decreased pks1 transcripts levels 82-92% in knockdown mutants when compared with the wild type and was accompanied with a reduction in melanin and swainsonine production. These results demonstrate that RNAi can be a useful tool for studying gene function in S. leguminicola.

  15. Discovering the role of the apolipoprotein gene and the genes in the putative pullulan biosynthesis pathway on the synthesis of pullulan, heavy oil and melanin in Aureobasidium pullulans.

    Science.gov (United States)

    Guo, Jian; Huang, Siyao; Chen, Yefu; Guo, Xuewu; Xiao, Dongguang

    2017-12-18

    Pullulan produced by Aureobasidium pullulans presents various applications in food manufacturing and pharmaceutical industry. However, the pullulan biosynthesis mechanism remains unclear. This work proposed a pathway suggesting that heavy oil and melanin may correlate with pullulan production. The effects of overexpression or deletion of genes encoding apolipoprotein, UDPG-pyrophosphorylase, glucosyltransferase, and α-phosphoglucose mutase on the production of pullulan, heavy oil, and melanin were examined. Pullulan production increased by 16.93 and 8.52% with the overexpression of UDPG-pyrophosphorylase and apolipoprotein genes, respectively. Nevertheless, the overexpression or deletion of other genes exerted little effect on pullulan biosynthesis. Heavy oil production increased by 146.30, 64.81, and 33.33% with the overexpression of UDPG-pyrophosphorylase, α-phosphoglucose mutase, and apolipoprotein genes, respectively. Furthermore, the syntheses of pullulan, heavy oil, and melanin can compete with one another. This work may provide new guidance to improve the production of pullulan, heavy oil, and melanin through genetic approach.

  16. The gene encoding the melanin-concentrating hormone receptor 1 is associated with schizophrenia in a Danish case-control sample

    DEFF Research Database (Denmark)

    Demontis, Ditte; Nyegaard, Mette; Christensen, Jane Hvarregaard

    2012-01-01

    OBJECTIVE: The MCHR1 gene encoding the melanin-concentrating hormone receptor 1 is located on chromosome 22q13.2 and has previously been associated with schizophrenia in a study of cases and controls from the Faroe Islands and Scotland. Herein we report an association between variations in the MCHR...

  17. Determination of catechol O-methyltransferase activity in relation to melanin metabolism using high-performance liquid chromatography with fluorimetric detection

    NARCIS (Netherlands)

    Smit, N. P.; Pavel, S.; Kammeyer, A.; Westerhof, W.

    1990-01-01

    A new sensitive method for the determination of catechol O-methyltransferase activity has been developed. The method is based on the O-methylation of the indolic intermediates of melanin metabolism. The substrate, 5,6-dihydroxyindole-2-carboxylic acid, is converted by the enzyme to two O-methylated

  18. New Biosynthetic Step in the Melanin Pathway of Wangiella (Exophiala) dermatitidis: Evidence for 2-Acetyl-1,3,6,8-Tetrahydroxynaphthalene as a Novel Precursor

    Science.gov (United States)

    The predominant cell wall melanin of Wangiella dermatitidis, a black fungal pathogen of humans, is synthesized from 1,8-dihydroxynaphthalene (D2HN). An early precursor, 1,3,6,8-tetrahydroxynaphthalene (T4HN), in the pathway leading to D2HN is reportedly produced as a pentaketide directly by an iter...

  19. Determination of melanin and haemoglobin in the skin of idiopathic cutaneous hyperchromia of the orbital region (ICHOR: A study of Indian patients

    Directory of Open Access Journals (Sweden)

    Michèle Verschoore

    2012-01-01

    Full Text Available Background: Idiopathic cutaneous hyperchromia at the orbital region (ICHOR is a cutaneous hyperchromia characterised by bilateral darkening of the eyelid and orbital skin that contrasts with the adjoining facial skin. ICHOR is frequent in dark skin. It interferes with the face appearance which often causes difficulties in societal acceptance and may impact quality of life. Objective : The aim of this investigation was to study the epidemiology, clinical features and risk factors associated with ICHOR in Indian patients and also to study the distribution of melanin and haemoglobin in ICHOR patients. This study also assessed the relevance of SIAscopy technique (spectrophotometric intracutaneous analysis (SIA, a new objective non-invasive method to measure melanin and haemoglobin concentration in vivo. Materials and Methods: Thirty-three patients diagnosed with ICHOR at the All India Institute of Medical Sciences, New Dehli, India, were included in the study. Epidemiological data were collected through a self-administrated questionnaire. Standard photographs were taken from each patient and SIAscopy measurements were done on dark circles and normal skin. Results: Surprisingly our study showed no significant correlation between ICHOR prevalence and family history, atopic and contact dermatitis, contemporaneous melasma and hormonal factors. The study confirms that sun exposure is a risk factor of dark circles aggravation. Indeed patients tend to reduce sun exposure after the onset of dark circles. SIAscopy analysis reveals significant differences in the concentration of total melanin, of dermal melanin and of haemoglobin between ICHOR skin and normal skin of the same patient. Conclusion: This study confirms that melanin deposits and blood stasis in dark circles may play a role in ICHOR pathogenesis and cause the darkening of skin under eyes. SIAscopy provides objective diagnostic information about ICHOR.

  20. Transcription factor VdCmr1 is required for pigment production, protection from UV irradiation, and regulates expression of melanin biosynthetic genes in Verticillium dahliae.

    Science.gov (United States)

    Wang, Yonglin; Hu, Xiaoping; Fang, Yulin; Anchieta, Amy; Goldman, Polly H; Hernandez, Gustavo; Klosterman, Steven J

    2018-04-01

    Verticillium dahliae is a soilborne fungus that causes vascular wilt diseases on numerous plant species worldwide. The production of darkly melanized microsclerotia is crucial in the disease cycle of V. dahliae, as these structures allow for long-term survival in soil. Previously, transcriptomic and genomic analysis identified a cluster of genes in V. dahliae that encodes some dihydroxynaphthalene (DHN) melanin biosynthetic pathway homologues found in related fungi. In this study, we explored the roles of cluster-specific transcription factor VdCmr1, as well as two other genes within the cluster encoding a polyketide synthase (VdPKS1) and a laccase (VdLac1), enzymes at initial and endpoint steps in DHN melanin production. The results revealed that VdCmr1 and VdPKS1 are required for melanin production, but neither is required for microsclerotia production. None of the three genes were required for pathogenesis on tobacco and lettuce. Exposure of ΔVdCmr1 and wild-type strains to UV irradiation, or to high temperature (40 °C), revealed an approx. 50 % reduction of survival in the ΔVdCmr1 strain, relative to the wild-type strain, in response to either condition. Expression profiles revealed that expression of some melanin biosynthetic genes are in part dependent on VdCmr1. Combined data indicate VdCmr1 is a key regulator of melanin biosynthesis, and that via regulation of melanogenesis, VdCmr1 affects survival of V. dahliae in response to abiotic threats. We conclude with a model showing regulation of VdCmr1 by a high osmolarity glycerol response (Hog)-type MAP kinase pathway.

  1. Effects of disrupting the polyketide synthase gene WdPKS1 in Wangiella [Exophiala] dermatitidis on melanin production and resistance to killing by antifungal compounds, enzymatic degradation, and extremes in temperature

    Directory of Open Access Journals (Sweden)

    Mandal Piyali

    2006-06-01

    Full Text Available Abstract Background Wangiella dermatitidis is a human pathogenic fungus that is an etiologic agent of phaeohyphomycosis. W. dermatitidis produces a black pigment that has been identified as a dihydroxynaphthalene melanin and the production of this pigment is associated with its virulence. Cell wall pigmentation in W. dermatitidis depends on the WdPKS1 gene, which encodes a polyketide synthase required for generating the key precursor for dihydroxynaphthalene melanin biosynthesis. Results We analyzed the effects of disrupting WdPKS1 on dihydroxynaphthalene melanin production and resistance to antifungal compounds. Transmission electron microscopy revealed that wdpks1Δ-1 yeast had thinner cell walls that lacked an electron-opaque layer compared to wild-type cells. However, digestion of the wdpks1Δ-1 yeast revealed small black particles that were consistent with a melanin-like compound, because they were acid-resistant, reacted with melanin-binding antibody, and demonstrated a free radical signature by electron spin resonance analysis. Despite lacking the WdPKS1 gene, the mutant yeast were capable of catalyzing the formation of melanin from L-3,4-dihyroxyphenylalanine. The wdpks1Δ-1 cells were significantly more susceptible to killing by voriconazole, amphotericin B, NP-1 [a microbicidal peptide], heat and cold, and lysing enzymes than the heavily melanized parental or complemented strains. Conclusion In summary, W. dermatitidis makes WdPKS-dependent and -independent melanins, and the WdPKS1-dependent deposition of melanin in the cell wall confers protection against antifungal agents and environmental stresses. The biological role of the WdPKS-independent melanin remains unclear.

  2. Chelator-Free and Biocompatible Melanin Nanoplatform with Facile-Loading Gadolinium and Copper-64 for Bioimaging.

    Science.gov (United States)

    Hong, Su Hyun; Sun, Yao; Tang, Chu; Cheng, Kai; Zhang, Ruiping; Fan, Quli; Xu, Liying; Huang, Daijuan; Zhao, Anthony; Cheng, Zhen

    2017-07-19

    Development of a chelator-free and biocompatible platform for the facile construction of gadolinium 3+ (Gd 3+ )-loaded nanoparticle based probes for in vivo magentic resonance imaging (MRI) is still challenging. Herein, biocompatible Gd 3+ -loading melanin dots (Gd-M-dots) have been easily prepared and have exhibited good loading efficiency for Gd 3+ , high stability, and higher T 1 relaxivity compared to the commercial Gd-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) agent. Furthermore, Gd-M-dots showed unique photoacoustic (PA) properties, and a high PA imaging signal could be observed in vivo 1 h after injection. Compared to the traditional Gd 3+ -loaded nanoparticles for single-modal MRI, Gd-M-dots can also be radiolabeled with 64 Cu 2+ for positron emission tomography. Overall, these attractive properties of Gd-M-dots render them a promising imaging agent for various biomedical applications.

  3. Fractal structure and the dynamics of aggregation of synthetic melanin in low pH aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.; Sung, J.; Eisner, M.; Moss, S.C.; Gallas, J.

    1989-01-01

    We have used static and dynamic light scattering to study the dynamics of aggregation of synthetic melanin, an amorphous biopolymeric substance, in low pH aqueous solution. We have found that, depending on the final pH value of the solutions, there existed two regimes of the aggregation kinetics, one corresponding to diffusion limited aggregation (DLA), and the other corresponding to reaction limited aggregation (RLA). The precipitates formed in these two regimes can be characterized by fractal structures. We have found fractal dimensions of d/sub f/ = 1.8 for the DLA clusters and d/sub f/ = 2.2 for the RLA clusters. These results agree well with the proposed limits of the fractal dimensions of the gold aggregates formed in aqueous solutions by Weitz et al.

  4. Interaction between p-BPA and precursor of melanin prepared from Greene's hamster melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Takase, M.; Yoshino, K.; Kamijo, M.; Niki, Y. [Shinshu Univ., Dept. of Chemistry, Matsumoto, Nagano (Japan); Kondoh, H.; Mishima, Y. [Mishima Inst. for Dermatological Research, Kobe, Hyogo (Japan); Hiratsuka, J. [Kawasaki Medical College, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan)

    2000-10-01

    We report on the first observation of p-Boronophenylalanine (p-BPA) complex signal of {sup 11}B-NMR which appeared at 8 ppm from BF{sub 3}OEt{sub 2} in the mixed solution of BPA and SGF (small granule fraction) among subcellular fractions of Greene's hamster melanoma. SGF contains coated vesicles (CV). CV organelles in melanoma cells contain a large amount of melanin monomers. The complex signal appeared at 2 hours after the mixing and gradually increased. At 6 hours after mixing it began to decrease and became broad at 8 hours after the mixing. On the other hand, there was no such a peak in BPA-LGF system. LGF (large granule fraction) does not contain CV. (author)

  5. Trace metals, melanin-based pigmentation and their interaction influence immune parameters in feral pigeons (Columba livia).

    Science.gov (United States)

    Chatelain, M; Gasparini, J; Frantz, A

    2016-04-01

    Understanding the effects of trace metals emitted by anthropogenic activities on wildlife is of great concern in urban ecology; yet, information on how they affect individuals, populations, communities and ecosystems remains scarce. In particular, trace metals may impact survival by altering the immune system response to parasites. Plumage melanin is assumed to influence the effects of trace metals on immunity owing to its ability to bind metal ions in feathers and its synthesis being coded by a pleiotropic gene. We thus hypothesized that trace metal exposure would interact with plumage colouration in shaping immune response. We experimentally investigated the interactive effect between exposure to an environmentally relevant range of zinc and/or lead and melanin-based plumage colouration on components of the immune system in feral pigeons (Columba livia). We found that zinc increased anti-keyhole limpet hemocyanin (KLH) IgY primary response maintenance, buffered the negative effect of lead on anti-KLH IgY secondary response maintenance and tended to increase T-cell mediated phytohaemagglutinin (PHA) skin response. Lead decreased the peak of the anti-KLH IgY secondary response. In addition, pheomelanic pigeons exhibited a higher secondary anti-KLH IgY response than did eumelanic ones. Finally, T-cell mediated PHA skin response decreased with increasing plumage eumelanin level of birds exposed to lead. Neither treatments nor plumage colouration correlated with endoparasite intensity. Overall, our study points out the effects of trace metals on some parameters of birds' immunity, independently from other confounding urbanization factors, and underlines the need to investigate their impacts on other life history traits and their consequences in the ecology and evolution of host-parasite interactions.

  6. Acetazolamide Inhibits the Level of Tyrosinase and Melanin: An Enzyme Kinetic, In Vitro, In Vivo, and In Silico Studies.

    Science.gov (United States)

    Abbas, Qamar; Raza, Hussain; Hassan, Mubashir; Phull, Abdul Rehman; Kim, Song Ja; Seo, Sung-Yum

    2017-09-01

    Melanin is the major factor that determines skin color and protects from ultraviolet radiation. In present study we evaluated the anti-melanogenesis effect of acetazolamide (ACZ) using four different approaches: enzyme kinetic, in vitro, in vivo and in silico. ACZ demonstrated significant inhibitory activity (IC 50 7.895 ± 0.24 μm) against tyrosinase as compared to the standard drug kojic acid (IC 50 16.84 ± 0.64 μm) and kinetic analyses showed that ACZ is a non-competitive inhibitor without cytotoxic effect. In in vitro experiments, A375 human melanoma cells were treated with 20 or 40 μm of ACZ with or without 50 μm of l-DOPA. Western blot results showed that ACZ significantly (P tyrosinase at 40 μm. Zebrafish embryos were treated with 10, 20 or 40 μm of ACZ and of positive control kojic acid. At 72 h of treatment with ACZ and kojic acid, ACZ significantly (P tyrosinase using PyRx tool. Docking studies suggested that His244, Asn260 and His85 are the major interacting residues in the binding site of the protein. In conclusion, our results suggest that ACZ is a good candidate for the inhibition of melanin and it could be used as a lead for developing the drugs for hyperpigmentary disorders and skin whitening. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  7. Effective melanin depigmentation of human and murine ocular tissues: an improved method for paraffin and frozen sections.

    Directory of Open Access Journals (Sweden)

    Caroline Manicam

    Full Text Available PURPOSE: The removal of excessive melanin pigments that obscure ocular tissue morphology is important to address scientific questions and for differential diagnosis of ocular tumours based on histology. Thus, the goal of the present study was to establish an effective and fast melanin bleaching method for paraffin and frozen mouse and human ocular tissues. METHODS: Paraffin-embedded and frozen ocular specimens from mice and human donors were subjected to bleaching employing two methods. The first employed potassium permanganate (KMnO4 with oxalic acid, and the second 10% hydrogen peroxide (H2O2. To determine optimal bleaching conditions, depigmentation was carried out at various incubation times. The effect of diluents used for 10% H2O2 was assessed using phosphate-buffered saline (PBS, and deionized water. Three different slide types and two fixatives, which were ice-cold acetone with 80% methanol, and 4% paraformaldehyde (PFA were used to determine the optimal conditions for better tissue adherence during bleaching. All tissues were stained in hematoxylin and eosin for histological evaluation. RESULTS: Optimal bleaching was achieved using warm 10% H2O2 diluted in PBS at 65°C for 120 minutes. Chromium-gelatin-coated slides prevented tissue detachment. Adherence of cryosections was also improved with post-fixation using 4% PFA and overnight air-drying at RT after cryosectioning. Tissue morphology was preserved under these conditions. Conversely, tissues bleached in KMnO4/oxalic acid demonstrated poor depigmentation with extensive tissue damage. CONCLUSIONS: Warm dilute H2O2 at 65°C for 120 minutes rapidly and effectively bleached both cryo- and paraffin sections of murine and human ocular tissues.

  8. Isochlorogenic acid A promotes melanin synthesis in B16 cell through the β-catenin signal pathway.

    Science.gov (United States)

    Mamat, Nuramina; Dou, Jun; Lu, Xueying; Eblimit, Aiden; Haji Akber, Aisa

    2017-09-01

    Isochlorogenic acid A, also called 3,5-dicaffeoylquinic acid (3,5-diCQA), is a widespread phenolic compound in the plant. Recent studies have shown that it has antioxidant and anti-inflammatory activity. In addition, oxidative stress and inflammation induced by solar ultraviolet radiation is a very significant reason for skin depigmentation. Therefore, in this study, we evaluated the effect of 3,5-diCQA on B16 cells and explored its molecular mechanism. Results showed that 3,5-diCQA upregulated intracellular melanin production in a time- and dose-dependent manner. Tyrosinase (TYR) activity was also increased after treatment with 3,5-diCQA in a dose-dependent manner. Expressions of TYR, TYR-related protein1, TYR-related protein2, and microphthalmia-associated transcription factor were upregulated in a dose-dependent manner after 48 h of treatment with 3,5-diCQA. Results also showed that 3,5-diCQA promoted the phosphorylation of Akt at Thr308 and glycogen synthase kinase-3β at Ser 9. Moreover, 3,5-diCQA increased the content of β-catenin in cell cytoplasm and nucleus by reducing the content of phosphorylated β-catenin (p-β-catenin). All these results suggest that 3,5-diCQA may mediate the acceleration of melanin synthesis by the β-catenin signal pathway. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Towards the development of a novel bioinspired functional material: Synthesis and characterization of hybrid TiO{sub 2}/DHICA-melanin nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pezzella, Alessandro; Capelli, Luigia [Dept. of Chemical Sciences, Via Cintia 4, 80126 Napoli (Italy); Costantini, Aniello [Dept. of Materials and Production Engineering, Piazzale Tecchio 80, 80125 Napoli (Italy); Luciani, Giuseppina, E-mail: luciani@unina.it [Dept. of Materials and Production Engineering, Piazzale Tecchio 80, 80125 Napoli (Italy); Tescione, Fabiana; Silvestri, Brigida [Dept. of Materials and Production Engineering, Piazzale Tecchio 80, 80125 Napoli (Italy); Vitiello, Giuseppe [Dept. of Chemical Sciences, Via Cintia 4, 80126 Napoli (Italy); Branda, Francesco [Dept. of Materials and Production Engineering, Piazzale Tecchio 80, 80125 Napoli (Italy)

    2013-01-01

    A large number of recent literature data focus on modification/modulation of surface chemistry of inorganic materials in order to improve their functional properties. Melanins, a wide class of natural pigments, are recently emerging as a powerful organic component for developing bioinspired active material for a large number of applications from organoelectronics to bioactive compounds. Here we report the use of the approach referred as 'chimie douce', involving in situ formation of the hybrids through reactions of precursors under mild conditions, to prepare novel hybrid functional architectures based on eumelanin like 5,6 dihydroxyindole-2-carboxylic acid (DHICA) polymer and TiO{sub 2}. Two synthesis procedures were carried out to get DHICA-melanin coated TiO{sub 2} nanoparticles as well as mixed DHICA/TiO{sub 2} hybrid nanostructures. Such systems were characterized through EPR, FT-IR and fluorescence spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and TEM microscopy in order to assess the effect of synthesis path as well as of DHICA content on structural, morphological and optical properties of TiO{sub 2} nanostructures. In particular, EPR, FT-IR spectra and TGA analysis confirmed the presence of DHICA-melanin in these samples. TEM measurements indicated the formation of the nanoparticles having relatively narrow size distribution with average particle size of about 10 nm. DHICA-melanin does act as a morphological agent affecting morphology of hybrid nanostructures. XRD analysis proved that TiO{sub 2} hybrid nanoparticles kept anatase structures for DHICA-melanin contents within the range of investigated compositions, i.e. up to 50% wt/wt. - Highlights: Black-Right-Pointing-Pointer TiO{sub 2}/DHICA melanin blends are novel hybrid functional architectures. Black-Right-Pointing-Pointer Two synthetic approaches were explored to produce TiO{sub 2}/DHICA nanostructures. Black-Right-Pointing-Pointer TiO{sub 2} nanorods prepared

  10. Involvement of a Polyketide Synthetase ClPKS18 in the Regulation of Vegetative Growth, Melanin and Toxin Synthesis, and Virulence inCurvularia lunata.

    Science.gov (United States)

    Gao, Jin-Xin; Chen, Jie

    2017-12-01

    The clpks18 gene was first cloned and identified in Curvularia lunata. It contains 6571 base pairs (bp) and an 6276 bp open reading frame encoding 2091 amino acids. The ClPKS18 deletion mutant displayed an albino phenotype, and almost lost the ability to product 5-(hydroxymethyl) furan-2-carboxylate (M5HF2C) toxin, implying that clpks18 gene in C. lunata is not only involved in 1,8-dihydroxynaphthalene melanin synthesis, but also relatively associated with M5HF2C toxin biosynthesis of the pathogen. The pathogenicity assays revealed that ΔClPKS18 was impaired in colonizing the maize leaves, which corresponds to the finding that ClPKS18 controls the production of melanin and M5HF2C in C. lunata . Results indicate that ClPKS18 plays a vital role in regulating pathogenicity of in C. lunata .

  11. Prostaglandin D2 production in FM55 melanoma cells is regulated by α-melanocyte-stimulating hormone and is not related to melanin production

    Science.gov (United States)

    Masoodi, Mojgan; Nicolaou, Anna; Gledhill, Karl; Rhodes, Lesley E; Tobin, Desmond J; Thody, Anthony J

    2010-01-01

    This study shows that prostaglandins in human FM55 melanoma cells and epidermal melanocytes are produced by COX-1. Prostaglandin production in FM55 melanoma cells was unrelated to that of melanin suggesting that the two processes can occur independently. α-Melanocyte-stimulating hormone, which had no effect on melanin production in FM55 cells, stimulated PGD2 production in these cells without affecting PGE2. While cAMP pathways may be involved in regulating PGD2 production, our results suggest that α-MSH acts independently of cAMP, possibly by regulating the activity of lipocalin-type PGD synthase. This α-MSH-mediated effect may be associated with its role as an immune modulator. PMID:20482620

  12. Mitigation of epidermal growth factor receptor inhibitor-induced side effects utilizing melanin and vascular-specific lasers: A case report series.

    Science.gov (United States)

    Kuo, Karen Y; Kwong, Bernice; Rahman, Zakia

    2017-10-01

    The advent of targeted chemotherapy has led to the emergence of new dermatologic toxicities. We sought to use lasers and light devices to treat recalcitrant cutaneous adverse effects related to cancer treatment. Three stage III or IV cancer patients with cutaneous complications due to epidermal growth factor receptor (EGFR) inhibitors were treated with melanin and vascular-specific laser and light technologies. Two patients reported reduction in papulopustular eruption following pulse dye laser (PDL) treatment. Two patients noted reduction in hair growth following intense pulsed light (IPL) and/or Alexandrite laser treatments. One patient was treated with both the PDL and IPL and reported improvement of both EGFR-induced hypertrichosis and papulopustular eruption. Laser and light devices targeting melanin and hemoglobin can be utilized to mitigate the cutaneous adverse effects associated with EGFR inhibitors in patients who have failed traditional therapies. This represents a new option for the cancer patient who is suffering from chemotherapy-induced side effects.

  13. Melanin production by a yeast strain XJ5-1 of Aureobasidium melanogenum isolated from the Taklimakan desert and its role in the yeast survival in stress environments.

    Science.gov (United States)

    Jiang, Hong; Liu, Nan-Nan; Liu, Guang-Lei; Chi, Zhe; Wang, Jian-Ming; Zhang, Ly-Ly; Chi, Zhen-Ming

    2016-07-01

    The yeast strain XJ5-1 isolated from the Taklimakan desert soil was identified to be a strain of Aureobasdium melanogenum and could produce a large amount of melanin when it was grown in the PDA medium, but its melanin biosynthesis and expression of the PKS gene responsible for the melanin biosynthesis was significantly repressed in the presence of (NH4)2SO4. However, A. melanogenum P5 strain isolated from a mangrove ecosystem grown in both the presence and the absence of (NH4)2SO4 did not produce any melanin. The cell size of A. melanogenum XJ5-1 strain was much higher than that of A. melanogenum P5 strain. The melanized cells of the yeast strain XJ5-1 had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), heat treatment (40 °C), salt shock (200.0 g/L NaCl), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than the non-melanized cells of the same yeast strain XJ5-1. At the same time, the melanized cells of the yeast strain XJ5-1 also had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than A. melanogenum P5 strain, but had similar resistance to heat treatment (40 °C) and salt shock (200.0 g/L NaCl) compared to those of A. melanogenum P5 strain. All the results revealed that many characteristics of A. melanogenum XJ5-1 isolated from the Taklimakan desert soil was different from those of A. melanogenum P5 strain isolated from the mangrove ecosystem.

  14. Anti-infective properties of the melanin-glucan complex obtained from medicinal tinder bracket mushroom, Fomes fomentarius (L.: Fr.) Fr. (Aphyllophoromycetideae).

    Science.gov (United States)

    Seniuk, Olga F; Gorovoj, Leontiy F; Beketova, Galina V; Savichuk, Hatalia O; Rytik, Petr G; Kucherov, Igor I; Prilutskay, Alla B; Prilutsky, Alexandr I

    2011-01-01

    The goal of this investigation was to comparatively study the efficiency of traditionally used anti-infective drugs and biopolymer complexes originated from the medicinal mushroom Fomes fomentarius (L.:Fr.) Fr.: 1) water-soluble melanin-glucan complex (MGC; -80% melanins and -20% beta-glucans) and 2) insoluble chitin-glucan-melanin complex (ChGMC; -70% chitin, -20% beta-glucans, and -10% melanins). Infectious materials (Helicobacter pylori, Candida albicans, and Herpes vulgaris I and HIV-1(zmb) were used in pure cultures of in vitro and in vivo models on experimental animals. Comparison studies of fungal biopolymers and effective modern antifungal, antibacterial, and antiviral drugs were used in in vitro models. The comparative clinical efficiency of ChGMC and of etiotropic pharmaceuticals in models of H. pylori, C. albicans, and H. vulgaris I infection contamination were studied. Using in vitro models, it was established that MGC completely depresses growth of C. albicans. MGC had an antimicrobial effect on H. pylori identical to erythromycin in all concentrations, and had a stronger action on this bacterium than other tested antibiotics. Tested MGC possesses simultaneously weak toxicity and high anti-HIV-1 activity in comparison with zidovudine (Retrovir). The obtained results show that CLUDDT therapy in Wistar rats with the application of ChGMC is, on average, 1.35-1.43 times as effective as a traditional one. Considering the absence of MGC and ChGMC toxic properties on blood cells even in very high concentrations, these complexes may be used as a source of biopolymers for the creation of essentially new agents for wide application in infectious pathology.

  15. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis.

    Science.gov (United States)

    Bilandžija, Helena; Ma, Li; Parkhurst, Amy; Jeffery, William R

    2013-01-01

    Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish) and several albino cave-dwelling forms (cavefish), albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.

  16. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis.

    Directory of Open Access Journals (Sweden)

    Helena Bilandžija

    Full Text Available Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish and several albino cave-dwelling forms (cavefish, albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.

  17. Caterpillar color patterns are determined by a two-phase melanin gene prepatterning process: new evidence from tan and laccase2.

    Science.gov (United States)

    Futahashi, Ryo; Banno, Yutaka; Fujiwara, Haruhiko

    2010-01-01

    The larval color patterns in Lepidoptera exhibit splendid diversity, and identifying the genes responsible for pigment distribution is essential to understanding color-pattern evolution. The swallowtail butterfly, Papilio xuthus, is a good candidate for analyzing marking-associated genes because its body markings change dramatically at the final molt. Moreover, the silkworm Bombyx mori is most suitable for identification of lab-generated color mutants because genome information and many color mutants are available. Here, we analyzed the expression pattern of 10 melanin-related genes in P. xuthus, and analyzed whether these genes were responsible for Bombyx larval color mutants. We found that seven genes correlated strongly with the stage-specific larval cuticular markings of P. xuthus, suggesting that, compared with Drosophila, more genes showed marking specificity in lepidopteran larvae. We newly found that the expression of both tan and laccase2 is strongly correlated with the larval black markings in both P. xuthus and B. mori. The results of F2 linkage analysis and mutant analysis strongly suggest that tan is the responsible gene for Bombyx larval color mutant rouge, and that tan is important in emphasizing black markings of lepidopteran larvae. Detailed comparison of temporal and spatial expression patterns showed that larval cuticular markings were regulated at two different phases. Marking-specific expression of oxidizing enzymes preceded the marking-specific expression of melanin synthesis enzymes at mRNA level, which is the reverse of the melanin synthesis step.

  18. Both a PKS and a PPTase are involved in melanin biosynthesis and regulation of Aureobasidium melanogenum XJ5-1 isolated from the Taklimakan desert.

    Science.gov (United States)

    Jiang, Hong; Liu, Guang-Lei; Chi, Zhe; Wang, Jian-Ming; Zhang, Ly-Ly; Chi, Zhen-Ming

    2017-02-20

    A PKS1 gene responsible for the melanin biosynthesis and a NPG1 gene in Aureobasidium melanogenum XJ5-1 were cloned and characterized. An ORF of the PKS1 gene encoding a protein with 2165 amino acids contained 6495bp while an ORF of the NPG1 gene encoding a protein with 340 amino acids had 1076bp. After analysis of their promoters, it was found that expression of both the PKS1 gene and the NPG1 gene was repressed by nitrogen sources and glucose, respectively. The PKS deduced from the cloned gene consisted of one ketosynthase, one acyl transferase, two acyl carrier proteins, one thioesterase and one cyclase while the PPTase belonged to the family Sfp-type. After disruption of the PKS1 gene and the NPG1 gene, expression of the PKS1 gene and the NPG1 gene and the melanin biosynthesis in the disruptants K5 and DP107 disappeared and expression of the PKS1 gene in the disruptant DP107 was also negatively influenced. However, after the NPG1 gene was complemented in the disruptant DP107, the melanin biosynthesis in the complementary strain BP17 was restored and expression of the PKS1 gene and the NPG1 gene was greatly enhanced, suggesting that the PKS was indeed activated and regulated by the PPTase and expression of the PKS1 gene and the NPG1 gene had a coordinate regulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Differences in the melanosome distribution within the epidermal melanin units and its association with the impairing background of leukoderma in vitiligo and halo nevi: a retrospective study.

    Science.gov (United States)

    Xiong, Xi-Xi; Ding, Gao-Zhong; Zhao, Wen-E; Li, Xue; Ling, Yu-Ting; Sun, Li; Gong, Qing-Li; Lu, Yan

    2017-07-01

    Skin color is determined by the number of melanin granules produced by melanocytes that are transferred to keratinocytes. Melanin synthesis and the distribution of melanosomes to keratinocytes within the epidermal melanin unit (EMU) within the skin of vitiligo patients have been poorly studied. The ultrastructure and distribution of melanosomes in melanocytes and surrounding keratinocytes in perilesional vitiligo and normal skin were investigated using transmission electron microscopy (TEM). Furthermore, we performed a quantitative analysis of melanosome distribution within the EMUs with scatter plot. Melanosome count within keratinocytes increased significantly compared with melanocytes in perilesional stable vitiligo (P vitiligo. Furthermore, melanosome counts within melanocytes and their surrounding keratinocytes in perilesional active vitiligo skin decreased significantly compared with the other groups. In addition, taking the means-standard error of melanosome count within melanocytes and keratinocytes in healthy controls as a normal lower limit, EMUs were graded into 3 stages (I-III). Perilesional active vitiligo presented a significantly different constitution in stages compared to other groups (P vitiligo. Active vitiligo varies in stages and in stage II, EMUs are slightly impaired, but can be resuscitated, providing a golden opportunity with the potential to achieve desired repigmentation with an appropriate therapeutic choice. Adverse milieu may also contribute to the low melanosome count in keratinocytes.

  20. Demonstration of tyrosinase in the vitiligo skin of human beings by a sensitive fluorometric method as well as by 14C(U)-L-tyrosine incorporation into melanin

    Energy Technology Data Exchange (ETDEWEB)

    Husain, I.; Vijayan, E.; Ramaiah, A.; Pasricha, J.S.; Madan, N.C.

    1982-03-01

    Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. The tyrosine activity in the vitiligo skin was about 4 to 37% of corresponding normal skin. The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. The enzyme from vitiligo and normal skin was severely inhibited by substance(s) of low molecular weight. The enzyme exhibits a lag of about 4 hr in the absence of added beta 3,4-dihydroxyphenylalanine and 1 hr in presence of 5 microM dopa. Tyrosinase from the normal and vitiligo skin was inhibited by excess concentration of tyrosine. The homogenates from vitiligo skin could synthesize melanin from C14(U)-L-Tyrosine. The rate of tyrosine incorporation into melanin by the epidermal homogenates is increased by 3,4-dihydroxyphenylalanine (dopa) disproportionate to its effect on tyrosinase activity. Based on the data presented in this paper it is concluded that melanocytes are present in the vitiligo skin. A tentative hypothesis is put forward to explain the lack of melanin synthesis by the vitiligo skin under in vivo conditions, although melanocytes are present.

  1. Analysis on unevenness of skin color using the melanin and hemoglobin components separated by independent component analysis of skin color image

    Science.gov (United States)

    Ojima, Nobutoshi; Fujiwara, Izumi; Inoue, Yayoi; Tsumura, Norimichi; Nakaguchi, Toshiya; Iwata, Kayoko

    2011-03-01

    Uneven distribution of skin color is one of the biggest concerns about facial skin appearance. Recently several techniques to analyze skin color have been introduced by separating skin color information into chromophore components, such as melanin and hemoglobin. However, there are not many reports on quantitative analysis of unevenness of skin color by considering type of chromophore, clusters of different sizes and concentration of the each chromophore. We propose a new image analysis and simulation method based on chromophore analysis and spatial frequency analysis. This method is mainly composed of three techniques: independent component analysis (ICA) to extract hemoglobin and melanin chromophores from a single skin color image, an image pyramid technique which decomposes each chromophore into multi-resolution images, which can be used for identifying different sizes of clusters or spatial frequencies, and analysis of the histogram obtained from each multi-resolution image to extract unevenness parameters. As the application of the method, we also introduce an image processing technique to change unevenness of melanin component. As the result, the method showed high capabilities to analyze unevenness of each skin chromophore: 1) Vague unevenness on skin could be discriminated from noticeable pigmentation such as freckles or acne. 2) By analyzing the unevenness parameters obtained from each multi-resolution image for Japanese ladies, agerelated changes were observed in the parameters of middle spatial frequency. 3) An image processing system modulating the parameters was proposed to change unevenness of skin images along the axis of the obtained age-related change in real time.

  2. A randomized, controlled, double-blind study evaluating melanin-encapsulated liposomes as a chromophore for laser hair removal of blond, white, and gray hair.

    Science.gov (United States)

    Sand, Michael; Bechara, Falk Georges; Sand, Daniel; Altmeyer, Peter; Hoffmann, Klaus

    2007-05-01

    Laser hair removal of blond and white hair is a complicated task with often unsatisfactory results as a result of a lack of laser-absorbing chromophore. In the present study, we investigated if repetitive external application of liposomal melanin (Lipoxome; Dalton Medicare B.V., Zevenbergschen Hoek, The Netherlands) enables removal of blond/white and gray hair with a diode laser. Forty-two areas of blond, gray, or white facial and body hair of 16 patients were treated with a liposomal melanin spray (Lipoxome) and 3 cycles of 800 nm diode laser at intervals of 8 weeks (28-40 J/cm). A control group of 16 patients applied physiological saline spray before diode laser treatment. Hair regrowth was measured 8 weeks after each cycle and additionally 6 months after the last treatment by counting the number of terminal hairs compared with baseline pretreatment values. Complications and treatment outcomes were documented. Mean regrowth in the liposomal melanin group was 83% after 3 treatment cycles. Six months after therapy, average terminal hair count compared with baseline pretreatment showed 14% reduction. Although significant difference was seen compared with the control group showing a 10% reduction of hair growth after 6 months (P hair compared with a control group. However, the clinically observed hair reduction was so weak that additional effort as well as higher costs argues against the application of the tested formulation.

  3. Polydopamine-Based 3D Colloidal Photonic Materials: Structural Color Balls and Fibers from Melanin-Like Particles with Polydopamine Shell Layers.

    Science.gov (United States)

    Kohri, Michinari; Yanagimoto, Kenshi; Kawamura, Ayaka; Hamada, Kosuke; Imai, Yoshihiko; Watanabe, Takaichi; Ono, Tsutomu; Taniguchi, Tatsuo; Kishikawa, Keiki

    2018-03-07

    Nature creates beautiful structural colors, and some of these colors are produced by nanostructural arrays of melanin. Polydopamine (PDA), an artificial black polymer produced by self-oxidative polymerization of dopamine, has attracted extensive attention because of its unique properties. PDA is a melanin-like material, and recent studies have reported that photonic materials based on PDA particles showed structural colors by enhancing color saturation through the absorption of scattered light. Herein, we describe the preparation of three-dimensional (3D) colloidal photonic materials, such as structural color balls and fibers, from biomimetic core-shell particles with melanin-like PDA shell layers. Structural color balls were prepared through the combined use of membrane emulsion and heating. We also demonstrated the use of microfluidic emulsification and solvent diffusion for the fabrication of structural color fibers. The obtained 3D colloidal materials, i.e., balls and fibers, exhibited angle-independent structural colors due to the amorphous assembly of PDA-containing particles. These findings provide new insight for the development of dye-free technology for the coloration of various 3D colloidal architectures.

  4. Screening of marine algae for potential tyrosinase inhibitor: those inhibitors reduced tyrosinase activity and melanin synthesis in zebrafish.

    Science.gov (United States)

    Cha, Seon-Heui; Ko, Seok-Chun; Kim, Daekyung; Jeon, You-Jin

    2011-04-01

    In order to find new anti-browning and whitening agents in this study, we investigated 43 indigenous marine algae for tyrosinase inhibitory activity. The extracts from Endarachne binghamiae, Schizymenia dubyi, Ecklonia cava (EC) and Sargassum silquastrum (SS) evidenced potent tyrosinase inhibitory activity similar to that of positive control, kojic acid. Among those marine algae, EC and SS are distributed abundantly on Jeju Island. Therefore, we selected those two species for further studies. Our results evidenced that both species reduced cellular melanin synthesis and tyrosinase activity. On the other hand, we utilized zebrafish as an alternative in vivo model. All the tested samples evidenced excellent inhibitory effects on the pigmentation of zebrafish, most likely due to their potential tyrosinase inhibitory activity. In simultaneous in vivo toxicity tests, no toxicity was observed in either algal species, on the other hand, toxicity was observed in positive controls. These results provided that EC and SS extract could be used as an ingredient for whiting cosmetics and that zebrafish is an alternative in vivo model. © 2010 Japanese Dermatological Association.

  5. Melanin and humic acid-like polymer complex from olive mill waste waters. Part I. Isolation and characterization.

    Science.gov (United States)

    Khemakhem, Maissa; Papadimitriou, Vassiliki; Sotiroudis, Georgios; Zoumpoulakis, Panagiotis; Arbez-Gindre, Cécile; Bouzouita, Nabiha; Sotiroudis, Theodore G

    2016-07-15

    A water soluble humic acid and melanin-like polymer complex (OMWW-ASP) was isolated from olive mill waste waters (OMWW) by ammonium sulfate fractionation to be used as natural additive in food preparations. The dark polymer complex was further characterized by a variety of biochemical, physicochemical and spectroscopic techniques. OMWW-ASP is composed mainly of proteins associated with polyphenols and carbohydrates and the distribution of its relative molecular size was determined between about 5 and 190 kDa. SDS-PAGE shows the presence of a well separated protein band of 21.3 kDa and a low molecular weight peptide. The OMWW-ASP complex exhibits a monotonically increasing UV-Vis absorption spectrum and it contains stable radicals. Antioxidant activity measurements reveal the ability of the OMWW protein fraction to scavenge both the cationic 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) radical, as well as the stable nitroxide free radical 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL). Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Unsuspected Intrinsic Property of Melanin to Dissociate Water Can Be Used for the Treatment of CNS Diseases.

    Science.gov (United States)

    Herrera, Arturo Solís; del Carmen Arias Esparza, María; Solís Arias, Paola Eugenia; Ávila-Rodriguez, Marco; Barreto, George Emilio; Li, Yi; Bachurin, Sergey Olegovich; Aliev, Gjumrakch

    2016-01-01

    Retinal adhesion mechanisms in mammals are quite complex and multifactorial in nature. To date, these mechanisms are incompletely understood due to a variety of chemical, physical, and physiological forces impinging upon retinal tissue: retinal pigment epithelium, nearby tissues as sclera and vitreous, the subretinal space, and the highly complex interphotoreceptor matrix that fills subretinal space. The adhesion of the retina to the choroid, rather than anatomical, is a dynamic process, as the retina detaches a few minutes after life ceases. The adhesion mechanisms described in the literature, such as intraocular pressure and the oncotic pressure of the choroid that seems to push the retina towards the choroid, the delicate anatomical relationships between the rod and cone photoreceptors, the retinal pigment epithelium, the existence of a complex material called interphotoreceptor matrix, as well as other metabolic and structural factors, still cannot explain the remarkable features observed in the adhesion mechanisms between the photoreceptor layer and retinal pigment epithelium cells. The unexpected intrinsic property of melanin to absorb light energy and transform it into chemically based free energy can explain normal adhesion of the sensory retina to the pigment epithelium. In this article, we explore and highlight this explanation, which states that it is definitely able to provide a new treatment avenue against devastating neurodegenerative properties.

  7. Abnormal response of melanin-concentrating hormone deficient mice to fasting: hyperactivity and rapid eye movement sleep suppression.

    Science.gov (United States)

    Willie, J T; Sinton, C M; Maratos-Flier, E; Yanagisawa, M

    2008-10-28

    Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that has been implicated in energy homeostasis. Pharmacological studies with MCH and its receptor antagonists have suggested additional behavioral roles for the neuropeptide in the control of mood and vigilance states. These suggestions have been supported by a report of modified sleep in the MCH-1 receptor knockout mouse. Here we found that MCH knockout (MCH(-)(/)(-)) mice slept less during both the light and dark phases under baseline conditions. In response to fasting, MCH(-)(/)(-) mice exhibited marked hyperactivity, accelerated weight loss and an exaggerated decrease in rapid eye movement (REM) sleep. Following a 6-h period of sleep deprivation, however, the sleep rebound in MCH(-)(/)(-) mice was normal. Thus MCH(-)(/)(-) mice adapt poorly to fasting, and their loss of bodyweight under this condition is associated with behavioral hyperactivity and abnormal expression of REM sleep. These results support a role for MCH in vigilance state regulation in response to changes in energy homeostasis and may relate to a recent report of initial clinical trials with a novel MCH-1 receptor antagonist. When combined with caloric restriction, the treatment of healthy, obese subjects with this compound resulted in some subjects experiencing vivid dreams and sleep disturbances.

  8. Melanin concentrating hormone and estrogen receptor-α are coexstensive but not coexpressed in cells of male rat hypothalamus

    Science.gov (United States)

    Muschamp, John W.; Hull, Elaine M.

    2009-01-01

    In male rats, estradiol (E2) exerts marked anorectic effects. One mechanism proposed for this effect is an E2-mediated down-regulation of the orexigenic neuropeptide melanin concentrating hormone (MCH). Previous anatomical work has shown that both MCH and estrogen receptor α (ERα) are found in quantity in the lateral hypothalamic area (LHA), a structure long associated with appetite and ingestive behavior. It has been hypothesized that the most direct manner by which E2 could affect MCH expression and feeding would be via classical nuclear ERα located in MCH neurons. To evaluate this notion, we performed double-label immunohistochemistry for MCH and ERα in male rat hypothalamus. We report here that MCH neurons do not contain ERα, suggesting that the primary locus for estrogenic control of feeding is not the MCH neurons themselves. Rather, we show substantial overlap in the anatomical distribution of both cell types, raising the possibility that E2 influences MCH signaling indirectly via adjacent ERα-containing cells. PMID:17933463

  9. Imaging melanin cancer growth in-vivo using raster-scan optoacoustic mesoscopy (RSOM) at 50 MHz and 100 MHz

    Science.gov (United States)

    Omar, Murad; Schwarz, Mathias; Soliman, Dominik; Symvoulidis, Panagiotis; Ntziachristos, Vasilis

    2016-03-01

    We used raster-scan optoacoustic mesoscopy (RSOM) at 50 MHz, and at 100 MHz, to monitor tumor growth, and tumor angiogenesis, which is a central hallmark of cancer, in-vivo. In this study we compared the performance, and the effect of the 50 MHz, and the 100 MHz frequencies on the quality of the final image. The system is based on a reflection-mode implementation of RSOM. The detectors used are custom made, ultrawideband, and spherically focused. The use of such detectors enables light coupling from the same side as the detector, thus reflection-mode. Light is in turn coupled using a fiber bundle, and the detector is raster scanned in the xy-plane. Subsequently, to retrieve small features, the raw data are reconstructed using a multi-bandwidth, beamforming reconstruction algorithm. Comparison of the system performance at the different frequencies shows as expected a higher resolution in case of the 100 MHz detector compared to the 50 MHz. On the other hand the 50 MHz has a better SNR, can detect features from deeper layers, and has higher angular acceptance. Based on these characteristics the 50 MHz detector was mostly used. After comparing the performance we monitored the growth of B16F10 cells, melanin tumor, over the course of 9 days. We see correspondence between the optoacoustic measurements and the cryoslice validations. Additionally, in areas close to the tumor we see sprouting of new vessels, starting at day 4-5, which corresponds to tumor angiogenesis.

  10. Photochemical interaction between the triplet state of 8-methoxypsoralen and the melanin precursor L-3,4 dihydroxyphenylalanine

    Energy Technology Data Exchange (ETDEWEB)

    Craw, M.; Truscott, T.G. (Paisley Coll. of Technology (UK)); Chedekel, M.R. (Johns Hopkins Univ., Baltimore, MD (USA). School of Hygiene and Public Health); Land, E.J. (Christie Hospital and Holt Radium Inst., Manchester (UK). Paterson Labs.)

    1984-02-01

    The photochemical interaction between 8-methoxypsoralen (8-MOP) and the melanin precursor L-3,4-dihydroxyphenylalanine (dopaH/sub 2/) has been studied using laser flash photolysis. Triplet excited 8-MOP was thus found to abstract electrons from dopaH/sub 2/ (k approx. 2 x 10/sup 9/ dm/sup 3/ mol/sup -1/ s/sup -1/) to form semireduced 8-MOP and semioxidised dopaH/sub 2/. The technique of pulse radiolysis was used to establish separately the spectra of (a) the semi-reduced form of 8-MOP at pH 6.5 and (b) the semioxidised forms of dopaH/sub 2/ at pH 6.5, 5.8, 4.6 and 3.3. The corresponding lambdasub(max) and extinction coefficients found were: for 8-MOP/sup -/ radical at pH 6.5, lambdasub(max) = 350 nm (epsilon = 9050 dm/sup 3/ mol/sup -1/ cm/sup -1/); for dopa/sup -/ radical at pH 6.5, lambdasub(max) = 305 nm (epsilon = 12000 dm/sup 3/ mol/sup -1/ cm/sup -1/) and for dopaH radical at pH 3.3, lambda = 305 nm (epsilon = 5900 dm/sup 3/ mol/sup -1/ cm/sup -1/).

  11. Regulation of miR-21 expression in human melanoma via UV-ray-induced melanin pigmentation.

    Science.gov (United States)

    Lin, Kuan-Yu; Chen, Chien-Min; Lu, Cheng-You; Cheng, Chun-Yuan; Wu, Yu-Hsin

    2017-08-01

    Excessive environmental ultraviolet (UV) radiation produces genetic mutations that can lead to skin cancer. This study was designed to assess the potential inhibitory activity of microRNA-21 (miR-21) on the UV irradiation-stimulated melanogenesis signal pathway in melanoma cells. The molecular mechanism of miR-21-induced inhibitory activity on UV-ray-stimulated melanogenesis-regulating proteins was examined in A375.S2 human melanoma and B16F10 mouse melanoma cells. UV irradiation for 30 min induced melanogenesis signal pathway by increasing melanin production and the number of A375.S2 cells. Similarly, UV radiation increased the expression of α-melanocyte-stimulating hormone (α-MSH) protein and decreased the melanogenesis-regulating signal, such as EGFR and Akt phosphorylation. Notably, miR-21 overexpression in UV-ray-stimulated A375.S2 cells decreased α-MSH expression and increased EGFR and Akt phosphorylation levels. Furthermore, miR-21 on UV-ray- induced melanogenesis was down-regulated by the Akt inhibitor and the EGFR inhibitor (Gefitinib). Results suggest that the suppressive activity of miR-21 on UV-ray-stimulated melanogenesis may involve the down-regulation of α-MSH and the activation in both of EGFR and Akt. © 2017 Wiley Periodicals, Inc.

  12. [Melanin Synthesis was Affected by Extracts of 22 Kinds Chinese Herbs of Acid Taste: an Experi- mental Study].

    Science.gov (United States)

    Zhang, Li-ping; Liang, Juan; Chen, Bin; Wang, Ying-hao

    2015-05-01

    To confirm the inhibitory effect of Chinese herbs of acid taste on melanin synthesis. Active ingredients of 22 kinds Chinese herbs of acid tastes were extracted by alkali extraction and acid precipitation, alcohol extraction, and water extraction, respectively, which was then dispensed into 25.00, 12.50, and 6.25 g/L suspension. Their effects on activities of tyrosinase were detected using mushroom-tyrosinase-DOPA speed oxidation. Their inhibition rates on activities of tyrosinase were respectively compared with inhibition rates of 1.0, 0.5, and 0.1 mmol/L arbutin. The 22 kinds Chinese herbs of acid taste included Cornus Officinalis, Crataegus pinnatifida, dark plum fruit, Schisandra Chinensis, Chaenomeles sinensis Koehne, Reynoutria japonica Houtt, Achyranthes Bidentata, Sanguisorba officinalis L., Semen Ziziphi Spinosae, Herba Ecliptae, blueberry, immature bitter orange, submature bitter orange, Prunus mume Var, Hovenia acerba Lindl., Fructus Mori, Pomegranate Rind, white paeony root, Rosa laevigata Michx., Portulaca oleracea L, Terminalia chebula Retz, Rhus chinensis Mill. Their alkaline extractions showed inhibition to activities of tyrosinase to different degrees except Herba Ecliptae. Of them, the highest inhibition rate (88.49% ± 9.98%) was got by dark plum fruit at 25 g/L, while the lowest inhibition rate (11.22% ± 3.36%) was got by immature bitter orange at 6.25 g/L. Their alcohol extractions showed inhibition to activities of tyrosinase to different degrees except Herba Ecliptae. Of them, the highest inhibition rate (75.92% ± 5.57%) was got by Hovenia acerba Lindl. at 25 g/L, while the lowest inhibition rate (9.60% ± 1.15%) was got by submature bitter orange at 6.25 g/L. Their water extractions all had inhibition on activities of tyrosinase. Of them, the highest inhibition rate (54.23% ± 3.56%) was got by Fructus Mori at 25 g/L, while the lowest inhibition rate (10.25% ± 1.83%) was got by Semen Ziziphi Spinosae at 6.25 g/L. Compared with 1 mmol

  13. Old males reduce melanin-pigmented traits and increase reproductive outcome under worse environmental conditions in common kestrels.

    Science.gov (United States)

    Lopez-Idiaquez, David; Vergara, Pablo; Fargallo, Juan Antonio; Martinez-Padilla, Jesús

    2016-02-01

    Secondary sexual traits displayed by males and females may have evolved as a signal of individual quality. However, both individual quality and investment on producing or maintaining enhanced sexual traits change as individuals age. At the same time, the costs associated to produce sexual traits might be attenuated or increased if environmental conditions are benign or worse respectively. Accordingly, environmental conditions are expected to shape the association between the expression of sexual traits and their reproductive outcome as individuals age. Nonetheless, little is known about the environmental influence on the co-variation between sexual traits and reproductive outcome throughout the life of individuals. We studied the age-dependency of the number and size of back spots, a melanin-based and sexual trait in adults of common kestrels (Falco tinnunculus). We analysed the age-dependence of reproductive traits and the environmental influence, defined as vole abundance, using a 10-year individual-based dataset. We broke down age-related changes of reproductive traits into within- and between-individual variation to assess their contribution to population-level patterns. Our results showed a within-individual decrease in the number, but not the size, of back spots in males. The size of back spots was positively correlated with food availability in males. Reproductive performance of males increased as they aged, in agreement with the life-history theory but depending of vole abundance. Remarkably, we found that having fewer back spots was positively associated with clutch size only for old individuals under low-food conditions. We suggest that environmental variation may shape the association between the expression of a sexual signal and reproductive outcome. We speculate that the reliability of sexual traits is higher when environmental conditions are poor only for old individuals. Within an evolutionary context, we suggest that the expression of sexual traits

  14. [Peculiarities of linear growth of the melanin-containing fungi Cladosporium sphaerospermum Penz. and Alternaria alternata (Fr.) Keissler].

    Science.gov (United States)

    Vember, V V; Zhdanova, N N

    2001-01-01

    Results on determination of radial (linear) growth rate of melanin-containing fungi Cladosporium sphaerospermum Penz. and Alternaria alternata (Fr.) Keissler concerning place of their isolation and ecologic peculiarities are presented in the paper. Essential differences, as to all studied indices of the strains of C. sphaerospermum strains, isolated from premices of the ChNPP 4th unit from the control strains of this species have been established. Only strain 34 of C. sphaerospermum, isolated from the cable driving region of the "Shelter" object, which did not differ from the control strains as to all the studied indices, made the exception. The radial growth rate was 2-4 times as low and variability amplitude 10-30 times as high in strains 60 and 5-1 of C. sphaerospermum, (which suffered high radiation load), as in the control strains of this species. The radial growth rate of C. sphaerospermum studied strains was an order lower as a whole than that of A. alternata strains. All the above said evidence for implementation of K-type vital strategy by C. sphaerospermum species and in this connection one can suppose its active growth on the surface of walls and ferroconcrete structures of the ChNPP 4th unit. Absence of differences, as to the studied radial growth indices, between A. alternata strains isolated from the ChNPP 4th unit premices and control strains of the species can evidence for the existence of A. alternata species under the conditions of high radioactivity in the surviving state.

  15. A Novel UV-Shielding and Transparent Polymer Film: When Bioinspired Dopamine-Melanin Hollow Nanoparticles Join Polymers.

    Science.gov (United States)

    Wang, Yang; Su, Jing; Li, Ting; Ma, Piming; Bai, Huiyu; Xie, Yi; Chen, Mingqing; Dong, Weifu

    2017-10-18

    Ultraviolet (UV) light is known to be harmful to human health and cause organic materials to undergo photodegradation. In this Research Article, bioinspired dopamine-melanin solid nanoparticles (Dpa-s NPs) and hollow nanoparticles (Dpa-h NPs) as UV-absorbers were introduced to enhance the UV-shielding performance of polymer. First, Dpa-s NPs were synthesized through autoxidation of dopamine in alkaline aqueous solution. Dpa-h NPs were prepared by the spontaneous oxidative polymerization of dopamine solution onto polystyrene (PS) nanospheres template, followed by removal of the template. Poly(vinyl alcohol) (PVA)/Dpa nanocomposite films were subsequently fabricated by a simple casting solvent. UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of Dpa-s versus Dpa-h NPs. In contrast to PVA/Dpa-s films, PVA/Dpa-h films exhibit stronger UV-shielding capabilities and can almost block the complete UV region (200-400 nm). The excellent UV-shielding performance of the PVA/Dpa-h films mainly arises from multiple absorption because of the hollow structure and large specific area of Dpa-h NPs. Moreover, the wall thickness of Dpa-h NPs can be simply controlled from 28 to 8 nm, depending on the ratio between PS and dopamine. The resulting films with Dpa-h NPs (wall thickness = ∼8 nm) maintained relatively high transparency to visible light because of the thinner wall thickness. The results indicate that the prepared Dpa-h NPs can be used as a novel UV absorber for next-generation transparent UV-shielding materials.

  16. Role of REM Sleep, Melanin Concentrating Hormone and Orexin/Hypocretin Systems in the Sleep Deprivation Pre-Ischemia.

    Science.gov (United States)

    Pace, Marta; Adamantidis, Antoine; Facchin, Laura; Bassetti, Claudio

    2017-01-01

    Sleep reduction after stroke is linked to poor recovery in patients. Conversely, a neuroprotective effect is observed in animals subjected to acute sleep deprivation (SD) before ischemia. This neuroprotection is associated with an increase of the sleep, melanin concentrating hormone (MCH) and orexin/hypocretin (OX) systems. This study aims to 1) assess the relationship between sleep and recovery; 2) test the association between MCH and OX systems with the pathological mechanisms of stroke. Sprague-Dawley rats were assigned to four experimental groups: (i) SD_IS: SD performed before ischemia; (ii) IS: ischemia; (iii) SD_Sham: SD performed before sham surgery; (iv) Sham: sham surgery. EEG and EMG were recorded. The time-course of the MCH and OX gene expression was measured at 4, 12, 24 hours and 3, 4, 7 days following ischemic surgery by qRT-PCR. A reduction of infarct volume was observed in the SD_IS group, which correlated with an increase of REM sleep observed during the acute phase of stroke. Conversely, the IS group showed a reduction of REM sleep. Furthermore, ischemia induces an increase of MCH and OX systems during the acute phase of stroke, although, both systems were still increased for a long period of time only in the SD_IS group. Our data indicates that REM sleep may be involved in the neuroprotective effect of SD pre-ischemia, and that both MCH and OX systems were increased during the acute phase of stroke. Future studies should assess the role of REM sleep as a prognostic marker, and test MCH and OXA agonists as new treatment options in the acute phase of stroke.

  17. Role of REM Sleep, Melanin Concentrating Hormone and Orexin/Hypocretin Systems in the Sleep Deprivation Pre-Ischemia.

    Directory of Open Access Journals (Sweden)

    Marta Pace

    Full Text Available Sleep reduction after stroke is linked to poor recovery in patients. Conversely, a neuroprotective effect is observed in animals subjected to acute sleep deprivation (SD before ischemia. This neuroprotection is associated with an increase of the sleep, melanin concentrating hormone (MCH and orexin/hypocretin (OX systems. This study aims to 1 assess the relationship between sleep and recovery; 2 test the association between MCH and OX systems with the pathological mechanisms of stroke.Sprague-Dawley rats were assigned to four experimental groups: (i SD_IS: SD performed before ischemia; (ii IS: ischemia; (iii SD_Sham: SD performed before sham surgery; (iv Sham: sham surgery. EEG and EMG were recorded. The time-course of the MCH and OX gene expression was measured at 4, 12, 24 hours and 3, 4, 7 days following ischemic surgery by qRT-PCR.A reduction of infarct volume was observed in the SD_IS group, which correlated with an increase of REM sleep observed during the acute phase of stroke. Conversely, the IS group showed a reduction of REM sleep. Furthermore, ischemia induces an increase of MCH and OX systems during the acute phase of stroke, although, both systems were still increased for a long period of time only in the SD_IS group.Our data indicates that REM sleep may be involved in the neuroprotective effect of SD pre-ischemia, and that both MCH and OX systems were increased during the acute phase of stroke. Future studies should assess the role of REM sleep as a prognostic marker, and test MCH and OXA agonists as new treatment options in the acute phase of stroke.

  18. Cutaneous metabolic pathway of tyrosine as a precursor to melanin in Asinara’s white donkey, Equus asinus L., 1758

    Directory of Open Access Journals (Sweden)

    Maria Grazia Cappai

    2015-10-01

    Full Text Available L-tyrosine (L-Tyr is a conditionally indispensable amino acid for Equids. The biologic role of L-Tyr is ubiquitous, being involved in the production of hair and skin pigments. The white donkeys of Asinara island display a peculiar white coat, with life-long hypopigmentation of skin, hairs and eyes. Our results underline how the white phenotype is due to a disorder of melanin biosynthesis, detected in skin biopsies and on hair bulbs through immunohistochemical and enzymatic assays. The metabolic pathway of L-Tyr is compatible with the clinical frame of ocular-cutaneous albinism (OCA. The enzymatic activity in hair bulbs for the conversion of L-Tyr to L-3,4-dihydroxyphenilalanine (L-DOPA tested negative, but positive for L-DOPA conversion into eumelanin in the 100% of the Asinara’s white donkey. This is the case of a negative-tyrosinase albinism, which contemporarily excludes dietary deficiencies of phenylalanine (Phe or L-Tyr and potential incapability of Tyr intestinal uptake or Tyr conversion from Phe. The tyrosinase (TYR residual activity positively and significantly (P=0.012 correlates (P=0.897 with the albino phenotype of the Asinara’s white donkey. These results definitely point to the fact that Asinara’s white donkey population owes its phenotype to TYR residual activity, thus on genetic basis. From a comparative point of view, the albino form of the Asinara’s white donkeys is similar to the human OCA type 1, from which however differs for positively testing to L-DOPA conversion, upon incubation of hair bulbs in L-DOPA solutions.

  19. Identification of mRNAs coding for mammalian-type melanin-concentrating hormone and its receptors in the scalloped hammerhead shark Sphyrna lewini.

    Science.gov (United States)

    Mizusawa, Kanta; Amiya, Noriko; Yamaguchi, Yoko; Takabe, Souichirou; Amano, Masafumi; Breves, Jason P; Fox, Bradley K; Grau, E Gordon; Hyodo, Susumu; Takahashi, Akiyoshi

    2012-10-01

    Melanin-concentrating hormone (MCH) is a neuromodulator, synthesized in the hypothalamus, that regulates both appetite and energy homeostasis in mammals. MCH was initially identified in teleost fishes as a pituitary gland hormone that induced melanin aggregation in chromatophores in the skin; however, this function of MCH has not been observed in other vertebrates. Recent studies suggest that MCH is involved in teleost feeding behavior, spurring the hypothesis that the original function of MCH in early vertebrates was appetite regulation. The present study reports the results of cDNAs cloning encoding preproMCH and two MCH receptors from an elasmobranch fish, Sphyrna lewini, a member of Chondrichthyes, the earliest diverged class in gnathostomes. The putative MCH peptide is composed of 19 amino acids, similar in length to the mammalian MCH. Reverse-transcription polymerase chain reaction revealed that MCH is expressed in the hypothalamus in S. lewini MCH cell bodies and fibers were identified by immunochemistry in the hypothalamus, but not in the pituitary gland, suggesting that MCH is not released via the pituitary gland into general circulation. MCH receptor genes mch-r1 and mch-r2 were expressed in the S. lewini hypothalamus, but were not found in the skin. These results indicate that MCH does not have a peripheral function, such as a melanin-concentrating effect, in the skin of S. lewini hypothalamic MCH mRNA levels were not affected by fasting, suggesting that feeding conditions might not affect the expression of MCH in the hypothalamus. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. SpectraCam®: A new polarized hyperspectral imaging system for repeatable and reproducible in vivo skin quantification of melanin, total hemoglobin, and oxygen saturation.

    Science.gov (United States)

    Nkengne, A; Robic, J; Seroul, P; Gueheunneux, S; Jomier, M; Vie, K

    2018-02-01

    An accurate way to determine skin pigmentation is to acquire the spectral reflectance of a skin sample and to quantify chromophores by reverse calculation from physical models of light propagation. Therefore, we tested a new hyperspectral imaging device and software suite, the SpectraCam ® system, and evaluated its accuracy to quantify skin chromophores. Validation of the SpectraCam ® system was performed by, firstly, comparing the known and the acquired reflectance spectra of color phantoms. Repeatability and reproducibility were then evaluated by two operators who performed acquisitions at different time points and compared the acquired reflectance spectra. The specificity of the system was tested by quantitative analysis of single chromophore variation models: lentigo and pressure relief. Finally, we tested the ability of the SpectraCam ® system to detect variations in chromophore in the eye region due to the daily application of a new anti-dark circle cosmetic product. The SpectraCam ® system faithfully acquires the reflectance spectra of color phantoms (r 2 >0.90). The skin reflectance spectra acquired by different operators at different times are highly repeatable (r 2 >0.94) and reproducible (r 2 >0.99). The SpectraCam ® system can also produce qualitative maps that reveal local variations in skin chromophore or underlying structures such as blood vessels. The system is precise enough to detect melanin variation in lentigo or total hemoglobin and oxygen saturation variations upon pressure relief. It is also sensitive enough to detect a decrease in melanin in the eye region due to the application of an anti-dark circle cosmetic product. The SpectraCam ® system proves to be rapid and produces high-resolution data encompassing a large field of view. It is a robust hyperspectral imaging system that quantifies melanin, total hemoglobin, and oxygen saturation and is well adapted to cosmetic research. © 2017 John Wiley & Sons A/S. Published by John Wiley

  1. A promising magnetic resonance stem cell tracer based on natural biomaterials in a biological system: manganese(II) chelated to melanin nanoparticles.

    Science.gov (United States)

    Liu, Shi-Jie; Wang, Ling-Jie; Qiao, Ying; Zhang, Hua; Li, Li-Ping; Sun, Jing-Hua; He, Sheng; Xu, Wen; Yang, Xi; Cai, Wen-Wen; Li, Jian-Ding; Wang, Bin-Quan; Zhang, Rui-Ping

    2018-01-01

    Melanin and manganese are both indispensable natural substances that play crucial roles in the human body. Melanin has been used as a multimodality imaging nanoplatform for biology science research because of its natural binding ability with metal ions (eg, 64 Cu 2+ , Fe 3+ , and Gd 3+ ). Because of its effects on T1 signal enhancement, Mn-based nanoparticles have been used in magnetic resonance (MR) quantitative cell tracking in vivo. Stem cell tracking in vivo is an essential technology used to characterize engrafted stem cells, including cellular viability, biodistribution, differentiation capacity, and long-term fate. In the present study, manganese(II) ions chelated to melanin nanoparticles [MNP-Mn(II)] were synthesized. The characteristics, stem cell labeling efficiency, and cytotoxicity of the nanoparticles were evaluated. MR imaging of the labeled stem cells in vivo and in vitro were also further performed. In T1 relaxivity (r1), MNP-Mn(II) were significantly more abundant than Omniscan. Bone marrow-derived stem cells (BMSCs) can be labeled easily by coincubating with MNP-Mn(II), suggesting that MNP-Mn(II) had high biocompatibility. Cell Counting Kit-8 assays revealed that MNP-Mn(II) had almost no cytotoxicity when used to label BMSCs, even with a very high concentration (1,600 µg/mL). BMSCs labeled with MNP-Mn(II) could generate a hyperintense T1 signal both in vitro and in vivo, and the hyperintense T1 signal in vivo persisted for at least 28 days. Taken together, our results showed that MNP-Mn(II) possessed many excellent properties for potential quantitative stem cell tracking in vivo.

  2. A promising magnetic resonance stem cell tracer based on natural biomaterials in a biological system: manganese (II chelated to melanin nanoparticles

    Directory of Open Access Journals (Sweden)

    Liu SJ

    2018-03-01

    Full Text Available Shi-Jie Liu,1,2,* Ling-Jie Wang,1,* Ying Qiao,1 Hua Zhang,1 Li-Ping Li,1 Jing-Hua Sun,1 Sheng He,1 Wen Xu,1,2 Xi Yang,1 Wen-Wen Cai,2 Jian-Ding Li,1 Bin-Quan Wang,3 Rui-Ping Zhang2 1Medical Imaging Department, First Clinical Medical College of Shanxi Medical University, Taiyuan, Shanxi, China; 2Imaging Department, Affiliated Tumor Hospital of Shanxi Medical University, Taiyuan, Shanxi, China; 3Department of Otolaryngology, Head & Neck Surgery, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China *These authors contributed equally to the paper Background: Melanin and manganese are both indispensable natural substances that play crucial roles in the human body. Melanin has been used as a multimodality imaging nanoplatform for biology science research because of its natural binding ability with metal ions (eg, 64Cu2+, Fe3+, and Gd3+. Because of its effects on T1 signal enhancement, Mn-based nanoparticles have been used in magnetic resonance (MR quantitative cell tracking in vivo. Stem cell tracking in vivo is an essential technology used to characterize engrafted stem cells, including cellular viability, biodistribution, differentiation capacity, and long-term fate.Methods: In the present study, manganese(II ions chelated to melanin nanoparticles [MNP-Mn(II] were synthesized. The characteristics, stem cell labeling efficiency, and cytotoxicity of the nanoparticles were evaluated. MR imaging of the labeled stem cells in vivo and in vitro were also further performed. In T1 relaxivity (r1, MNP-Mn(II were significantly more abundant than Omniscan. Bone marrow-derived stem cells (BMSCs can be labeled easily by coincubating with MNP-Mn(II, suggesting that MNP-Mn(II had high biocompatibility.Results: Cell Counting Kit-8 assays revealed that MNP-Mn(II had almost no cytotoxicity when used to label BMSCs, even with a very high concentration (1,600 µg/mL. BMSCs labeled with MNP-Mn(II could generate a hyperintense T1 signal both in vitro

  3. Meta-analysis of melanin-concentrating hormone signaling-deficient mice on behavioral and metabolic phenotypes.

    Directory of Open Access Journals (Sweden)

    Kenkichi Takase

    Full Text Available The demand for meta-analyses in basic biomedical research has been increasing because the phenotyping of genetically modified mice does not always produce consistent results. Melanin-concentrating hormone (MCH has been reported to be involved in a variety of behaviors that include feeding, body-weight regulation, anxiety, sleep, and reward behavior. However, the reported behavioral and metabolic characteristics of MCH signaling-deficient mice, such as MCH-deficient mice and MCH receptor 1 (MCHR1-deficient mice, are not consistent with each other. In the present study, we performed a meta-analysis of the published data related to MCH-deficient and MCHR1-deficient mice to obtain robust conclusions about the role of MCH signaling. Overall, the meta-analysis revealed that the deletion of MCH signaling enhanced wakefulness, locomotor activity, aggression, and male sexual behavior and that MCH signaling deficiency suppressed non-REM sleep, anxiety, responses to novelty, startle responses, and conditioned place preferences. In contrast to the acute orexigenic effect of MCH, MCH signaling deficiency significantly increased food intake. Overall, the meta-analysis also revealed that the deletion of MCH signaling suppressed the body weight, fat mass, and plasma leptin, while MCH signaling deficiency increased the body temperature, oxygen consumption, heart rate, and mean arterial pressure. The lean phenotype of the MCH signaling-deficient mice was also confirmed in separate meta-analyses that were specific to sex and background strain (i.e., C57BL/6 and 129Sv. MCH signaling deficiency caused a weak anxiolytic effect as assessed with the elevated plus maze and the open field test but also caused a weak anxiogenic effect as assessed with the emergence test. MCH signaling-deficient mice also exhibited increased plasma corticosterone under non-stressed conditions, which suggests enhanced activity of the hypothalamic-pituitary-adrenal axis. To the best of our

  4. Cerebrospinal fluid melanin-concentrating hormone (MCH and hypocretin-1 (HCRT-1, orexin-A in Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Frank M Schmidt

    Full Text Available Ancillary to decline in cognitive abilities, patients with Alzheimer's disease (AD frequently suffer from behavioural and psychological symptoms of dementia (BPSD. Hypothalamic polypeptides such as melanin-concentrating hormone (MCH and hypocretin-1 (HCRT-1, orexin-A are promoters of sleep-wake regulation and energy homeostasis and are found to impact on cognitive performance. To investigate the role of MCH and HCRT-1 in AD, cerebrospinal fluid (CSF levels were measured in 33 patients with AD and 33 healthy subjects (HS using a fluorescence immunoassay (FIA. A significant main effect of diagnosis (F(1,62 = 8.490, p<0.01 on MCH levels was found between AD (93.76±13.47 pg/mL and HS (84.65±11.40 pg/mL. MCH correlated with T-tau (r = 0.47; p<0.01 and P-tau (r = 0.404; p<0.05 in the AD but not in the HS. CSF-MCH correlated negatively with MMSE scores in the AD (r = -0.362, p<0.05 and was increased in more severely affected patients (MMSE≤20 compared to HS (p<0.001 and BPSD-positive patients compared to HS (p<0.05. In CSF-HCRT-1, a significant main effect of sex (F(1,31 = 4.400, p<0.05 with elevated levels in females (90.93±17.37 pg/mL vs. 82.73±15.39 pg/mL was found whereas diagnosis and the sex*diagnosis interaction were not significant. Elevated levels of MCH in patients suffering from AD and correlation with Tau and severity of cognitive impairment point towards an impact of MCH in AD. Gender differences of CSF-HCRT-1 controversially portend a previously reported gender dependence of HCRT-1-regulation. Histochemical and actigraphic explorations are warranted to further elucidate alterations of hypothalamic transmitter regulation in AD.

  5. Compounds isolated from the aerial part of Crataegus azarolus inhibit growth of B16F10 melanoma cells and exert a potent inhibition of the melanin synthesis.

    Science.gov (United States)

    Mustapha, Nadia; Bzéouich, Imèn Mokdad; Ghedira, Kamel; Hennebelle, Thierry; Chekir-Ghedira, Leila

    2015-02-01

    Poor therapeutic results have been reported for treatment of malignant melanoma; therefore in this study, we have investigated inhibitory capacity of vitexin-2''-O-rhamnoside as well as the extract from which it was isolated, i.e. the ethyl acetate extract obtained from the leaves of Crataegus azarolus, on mouse melanoma (B16F10) proliferation. Cell viability was determined using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In addition, amounts of melanin and tyrosinase were measured spectrophotometrically at 475nm. Ethyl acetate extract and vitexin-2''-O-rhamnoside exhibited significant anti-proliferative activity against B16F10 melanoma cells after incubation for 48hours with IC50s of 50μg/mL and 20μM, respectively. Furthermore, these two compounds have the ability to reduce the melanin content by inhibiting the tyrosinase activity of B16F10 cells. Thus, further investigations are merited to ascertain their potential application in treating hyperpigmentation disorders. Copyright © 2014. Published by Elsevier Masson SAS.

  6. Hematite photoanode co-functionalized with self-assembling melanin and C-phycocyanin for solar water splitting at neutral pH

    Energy Technology Data Exchange (ETDEWEB)

    Schrantz, Krisztina; Wyss, Pradeep P.; Ihssen, Julian; Toth, Rita; Bora, Debajeet K.; Vitol, Elina A.; Rozhkova, Elena A.; Pieles, Uwe; Thöny-Meyer, Linda; Braun, Artur

    2017-04-01

    tNature provides functional units which can be integrated in inorganic solar cell materials, such as lightharvesting antenna proteins and photosynthetic molecular machineries, and thus help in advancing artifi-cial photosynthesis. Their integration needs to address mechanical adhesion, light capture, charge transferand corrosion resistance. We showed recently how enzymatic polymerization of melanin can immobi-lize the cyanobacterial light harvesting protein C-phycocyanin on the surface of hematite, a prospectivemetal oxide photoanode for solar hydrogen production by water splitting in photoelectrochemical cells.After the optimization of the functionalization procedure, in this work we show reproducible hydrogenproduction, measured parallel to the photocurrent on this bio-hybrid electrode in benign neutral pHphosphate. Over 90% increase compared to the photocurrent of the pristine hematite could be achieved.The hydrogen evolution was monitored during the photoelectrochemical measurement in an improvedphotoelectrochemical cell. The C-phycocyanin-melanin coating on the hematite was shown to exhibit acomb-like fractal pattern. Raman spectroscopy supported the presence of the protein on the hematiteanode surface. The stability of the protein coating is demonstrated during the 2 h GC measurement andthe 24 h operando current density measurement

  7. Schinus terebinthifolius Raddi extract and linoleic acid from Passiflora edulis synergistically decrease melanin synthesis in B16 cells and reconstituted epidermis.

    Science.gov (United States)

    Jorge, A T S; Arroteia, K F; Santos, I A; Andres, E; Medina, S P H; Ferrari, C R; Lourenço, C B; Biaggio, R M T T; Moreira, P L

    2012-10-01

    Several treatments for skin whitening are available today, but few of them are completely adequate, especially owing to the carcinogenic potential attributed to classical drugs like hydroquinone, arbutin and kojic acid. To provide an alternative and safer technology for whitening, we developed two botanical compounds originated from Brazilian biodiversity, an extract of Schinus terebinthifolius Raddi and a linoleic acid fraction isolated from Passiflora edulis oil. The whitening effect of these compounds was assessed using biochemical assays and in vitro models including cellular assays and equivalent skin. The results showed that S. terebinthifolius Raddi extract is able to reduce the tyrosinase activity in vitro, and the combination of this extract with linoleic acid is able to decrease the level of melanin produced by B16 cells cultured with melanocyte-stimulating hormone. Furthermore, melanin was also reduced in human reconstituted epidermis (containing melanocytes) treated with the compounds. The combination of the compounds may provide a synergistic positive whitening effect rather than their isolated use. Finally, we demonstrated that the performance of these mixed compounds is comparable to classical molecules used for skin whitening, as kojic acid. This new natural mixture could be considered an alternative therapeutic agent for treating hyperpigmentation and an effective component in whitening cosmetics. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  8. An experimental test of the role of structural blue and melanin-based chestnut coloration in aggressive contests in male eastern bluebirds

    Directory of Open Access Journals (Sweden)

    Austin eMercadante

    2014-06-01

    Full Text Available Male eastern bluebirds (Sialia sialis have feathers with either structurally based blue coloration or melanin-based chestnut coloration, and they hold territories during the breeding season that they defend vigorously. We tested whether the melanin pigmentation or structural coloration of feathers serve as signals during intrasexual aggressive encounters by placing color-modified stuffed bluebirds in male territories. We recorded the time to attack and the intensity of attacks on each model, and we then compared the response to color-enhanced versus color-reduced models. Male bluebirds attacked models with brighter and more chromatic blue coloration significantly more often than they attacked models with darker and less chromatic blue coloration. In contrast, the darkness of the chestnut breast coloration did not have a significant effect on the rate at which models were attacked. We conclude that territorial male bluebirds perceive intruding males with brighter blue coloration as a greater threat than males with drabber blue coloration, presumably because blue coloration is a signal of fighting ability. In contrast, the chestnut coloration of breast feathers appears to be a signal of gender and sexual maturity and not a graded signal of social status.

  9. Hair Dyes Resorcinol and Lawsone Reduce Production of Melanin in Melanoma Cells by Tyrosinase Activity Inhibition and Decreasing Tyrosinase and Microphthalmia-Associated Transcription Factor (MITF Expression

    Directory of Open Access Journals (Sweden)

    Shu-Mei Lee

    2015-01-01

    Full Text Available Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  10. Regulation of 20-hydroxyecdysone on the larval pigmentation and the expression of melanin synthesis enzymes and yellow gene of the swallowtail butterfly, Papilio xuthus.

    Science.gov (United States)

    Futahashi, Ryo; Fujiwara, Haruhiko

    2007-08-01

    The swallowtail butterfly, Papilio xuthus, changes its larval body pattern dramatically during the fourth ecdysis. Cuticular pigmentation occurs with precise timing just before ecdysis. We previously found that the cuticular pigmentation was regulated by three melanin synthesis genes, tyrosine hydroxylase (TH), dopa decarboxylase (DDC), and ebony. We discovered that yellow is strongly expressed in the presumptive black markings earlier than TH and DDC. Because the ecdysis is triggered by 20-hydroxyecdysone (20E), the effects of 20E on the pigmentation and expression of the melanin synthesis genes were examined. Here, we established a method for the topical application of 20E to molting specimens, so that 20E has only a partial effect, resulting in successful ecdysis. When we applied 20E during the mid-phase of the molting period, when the 20E titer is declining, cuticular pigmentation was completely inhibited. The cessation of hormonal treatments caused delayed pigmentation. yellow expression was promoted by a high titer of 20E, whereas the expression of TH, DDC, and ebony was suppressed, suggesting that a decline in the 20E concentration is necessary for the induction of the expression of the latter three genes. These results indicate that cuticular pigmentation is controlled by the exposure to 20E and its removal.

  11. The Amount of Melanin Influences p16 Loss in Spitzoid Melanocytic Lesions: Correlation With CDKN2A Status by FISH and MLPA.

    Science.gov (United States)

    Martinez Ciarpaglini, Carolina; Gonzalez, Jose; Sanchez, Beatriz; Agusti, Jaime; Navarro, Lara; Nieto, Gema; Monteagudo, Carlos

    2018-02-27

    The risk assessment of spitzoid lesions is one of the most difficult challenges in dermatopathology practice. In this regard, the loss of p16 expression and the homozygous deletion of CDKN2A, have been pointed in the literature as reliable indicators of high risk. However, these findings are poorly reproducible, and the molecular bases underlying the loss of p16 expression remain unclear. We aimed to identify the underlying events causing loss of CDKN2A/p16 in spitzoid tumors. We evaluated the immunohistochemical expression of p16, and the presence of CDKN2A genetic alterations detected through fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA), in a series of 130 Spitz nevi, 20 atypical spitzoid tumors, and 11 spitzoid melanoma. We found a significant loss of p16 expression in cases with high amount of melanin content in the 3 groups (P<0.000001) and a similar proportion of p16-negative cases in the group of Spitz nevi and atypical spitzoid tumors. MLPA allowed the recognition of CDKN2A microdeletions, which correlated with p16 loss (P=0.01). MLPA and FISH were more accurate than immunohistochemistry to detect CDKN2A alterations; although contrary to MLPA, FISH fails to recognize CDKN2A microdeletions. According to our results, p16 expression may be useful in the study of cases with atypical features and low melanin content, but it has no value in highly pigmented spitzoid lesions.

  12. Using a melanin granule lattice model to study the thermal effects of pulsed and scanning light irradiations through a measurement aperture

    Science.gov (United States)

    Kim, Do-Hyun

    2011-12-01

    Optical radiation hazards of scanning light sources are often evaluated using pulsed light source criteria, with the relevant pulse parameter equivalent to the scanning light source determined by the energy delivered through a measurement aperture. However, physical equivalence has not been completely understood: a pulsed light source is temporally dynamic but spatially stationary, while a scanning light source is temporally stationary but spatially dynamic. This study introduces a numerical analysis based upon the melanin granule lattice model to investigate the equivalence of scanning and pulsed light sources through a measurement aperture and their respective thermal effects in the pigmented retinal layer. The numerical analysis calculates the thermal contribution of individual melanin granules with varying temporal sequence, and finds that temperature changes and thermal damage thresholds for the two different types of light sources were not equal. However, dwell times of 40 to 200 μsec did not produce significant differences between pulsed and scanning light sources in temperature change and thermal damage thresholds to the sample tissue.

  13. Effect of UVC, UVB, UVA and a solar simulator on the survival of mouse melanoma cell lines differing in melanin content

    Energy Technology Data Exchange (ETDEWEB)

    Hill, H.Z.; Hill, G.J.; Cieszka, K.; Azure, M. [New Jersey Medical School, Newark, NJ (United States)

    1994-12-31

    These studies were designed to determine the survival of cells that vary in constitutive pigment levels after exposure to different UV wave lengths. The lamps employed emitted UVC (near monochromatic 254 nm), UVB (Philips TL01-88.7% of UV output is UVB), UVA (Philips HPW125-89% of output is at 365 nm) and Westinghouse FS20 (broad band UVB and UVA). Dish lids were used to cut off UVC in the UVB and FS20 experiments and 0.25 inch plate glass was used to cut off UVB in the UVA experiments. UVC photons interact with putative intracellular photosensitizers which in turn convert O{sub 2} to active oxygen species which damage DNA to produce strand breaks, cross links and base damage. UVB acts by both mechanisms. The two cell lines studied were Cloudman S91/I3 (3.6 pg melanin/cell) and the closely related S91/amel (1.2 pg melanin/cell). Attached cells were covered with Ca{sup ++} and Mg{sup ++} free PBS and irradiated in the cold. Colonies were scored after 2 weeks. The two cell lines exhibit similar survival kinetics after UVC. S91/IE is more sensitive to killing by either UVB (TL01) or UVA. However, S91/amel cells are more sensitive to killing by UVB plus UVA (FS20). It is clear that UV of different qualities can interact to produce effects that would not be predicted based on responses to monochromatic wave lengths.

  14. Augmentation by L-Dopa of growth inhibition and melanin formation of X-irradiated Harding-Passey melanoma cells in culture

    Energy Technology Data Exchange (ETDEWEB)

    Schachtschabel, D.O.; Pfab, R.; Hess, F.; Paul, N.

    1988-07-01

    Treatment of exponentially proliferating melanogenic Harding-Passey melanoma cells in monolayer culture (HPM-73 line) with a single dose of X-irradiation (up to 8 Gy) or continuously (for several weeks) with L-3,4-dihydroxyphenylalanine (L-Dopa) up to 5x10/sup -4/ M resulted in a dose-dependent inhibition of cell proliferation, but not in death of all cells. Actually, 8 Gy-irradiated or L-Dopa (2x10/sup -4/ M)-treated cultures finally reached the cell number and cell density of controls. However, a combination of a single dose of radiation (8 Gy) followed by L-Dopa (2x10/sup -4/ M)-treatment resulted in destruction of all cells. Melanin formation was stimulated by L-dopa-treatment or X-irradiation, and was further elevated by the combined application of radiation and L-Dopa-exposure. Whether the effects of exogenously applied L-Dopa, an intermediary metabolite of melanin synthesis, are due to the conversion to growth-inhibitory metabolites (quinones, radicals, etc.) inside or outside the cell, was discussed. The latter might result from release (due to membrane damage or cell desintegration) of tyrosinase or/and melanosomes into the culture medium with the consequence of extracellular synthesis of potentially cytotoxic metabolites from medium substrates. Further, endocytosis of exogenous melanosomes and tyrosinase with potentially harmful effects is feasible. An application of such a combination therapy of melanoma to clinical medicine should be considered.

  15. Augmentation by L-Dopa of growth inhibition and melanin formation of X-irradiated Harding-Passey melanoma cells in culture

    International Nuclear Information System (INIS)

    Schachtschabel, D.O.; Pfab, R.; Hess, F.; Paul, N.

    1988-01-01

    Treatment of exponentially proliferating melanogenic Harding-Passey melanoma cells in monolayer culture (HPM-73 line) with a single dose of X-irradiation (up to 8 Gy) or continuously (for several weeks) with L-3,4-dihydroxyphenylalanine (L-Dopa) up to 5x10 -4 M resulted in a dose-dependent inhibition of cell proliferation, but not in death of all cells. Actually, 8 Gy-irradiated or L-Dopa (2x10 -4 M)-treated cultures finally reached the cell number and cell density of controls. However, a combination of a single dose of radiation (8 Gy) followed by L-Dopa (2x10 -4 M)-treatment resulted in destruction of all cells. Melanin formation was stimulated by L-dopa-treatment or X-irradiation, and was further elevated by the combined application of radiation and L-Dopa-exposure. Whether the effects of exogenously applied L-Dopa, an intermediary metabolite of melanin synthesis, are due to the conversion to growth-inhibitory metabolites (quinones, radicals, etc.) inside or outside the cell, was discussed. The latter might result from release (due to membrane damage or cell desintegration) of tyrosinase or/and melanosomes into the culture medium with the consequence of extracellular synthesis of potentially cytotoxic metabolites from medium substrates. Further, endocytosis of exogenous melanosomes and tyrosinase with potentially harmful effects is feasible. An application of such a combination therapy of melanoma to clinical medicine should be considered. (orig.) [de

  16. Hair dyes resorcinol and lawsone reduce production of melanin in melanoma cells by tyrosinase activity inhibition and decreasing tyrosinase and microphthalmia-associated transcription factor (MITF) expression.

    Science.gov (United States)

    Lee, Shu-Mei; Chen, Yi-Shyan; Lin, Chih-Chien; Chen, Kuan-Hung

    2015-01-09

    Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone) are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF) in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  17. Effects of a turmeric extract (Curcuma longa) on chronic ultraviolet B irradiation-induced skin damage in melanin-possessing hairless mice.

    Science.gov (United States)

    Sumiyoshi, Maho; Kimura, Yoshiyuki

    2009-12-01

    Turmeric (the rhizomes of Curcuma longa L., Zingiberacease) is widely used as a dietary pigment and spice, and has been traditionally used for the treatment of inflammation, skin wounds and hepatic disorders in Ayurvedic, Unani and Chinese medicine. Although the topical application or oral administration of turmeric is used to improve skin trouble, there is no evidence to support this effect. The aim of this study was to clarify whether turmeric prevents chronic ultraviolet B (UVB)-irradiated skin damage. We examined the effects of a turmeric extract on skin damage including changes in skin thickness and elasticity, pigmentation and wrinkling caused by long-term, low-dose ultraviolet B irradiation in melanin-possessing hairless mice. The extract (at 300 or 1000 mg/kg, twice daily) prevented an increase in skin thickness and a reduction in skin elasticity induced by chronic UVB exposure. It also prevented the formation of wrinkles and melanin (at 1000 mg/kg, twice daily) as well as increases in the diameter and length of skin blood vessels and in the expression of matrix metalloproteinase-2 (MMP-2). Prevention of UVB-induced skin aging by turmeric may be due to the inhibition of increases in MMP-2 expression caused by chronic irradiation.

  18. Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone.

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yi Ming; Meyer, Kristen M; Praseuth, Michael; Baker, Scott E; Bruno, Kenneth S; Wang, Clay C

    2010-12-06

    The genome sequencing of the fungus Aspergillus niger, an industrial workhorse, uncovered a large cache of genes encoding enzymes thought to be involved in