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Sample records for ommastrephes bartrami melanin

  1. Fluctuation in Ommastrephe bartrami yield in the North Pacific

    Institute of Scientific and Technical Information of China (English)

    ZHENG Rui; CHEN Ge

    2008-01-01

    The fluctuation in Ommastrephe bartrami yield from 1995 to 2001 in the North Pacific was shown obvious, on which this study was conducted using data of sea surface temperature (SST), chlorophyll-a (chl-a) and statistical production. The study shows that, cool water and low food abundance caused by abnormal Kuroshio resulted in the reduction in abundance of O. bartrami, which was worsened by excessive catch and the unawareness to local fishery resources protection.

  2. The study on fishing ground of neon flying squid, Ommastrephes bartrami, and ocean environment based on remote sensing data in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; WU Yumei; CUI Xuesen

    2009-01-01

    The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature (SST), chlorophyll concentration (Chl-a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results show that the favorable temperature for neon flying squid living is 10℃-22℃ and the favorite temperature is between 15℃-17℃. The Chl-a concentration is 0.1-0.6 mg/m3. When Chl-a concentration changes to 0.12-0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds,the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward during October-November, and the characteristics of the both migrations are very different. When squids migrate to the north, most relationships between the yields and SST are positive. The relationships are negative when squids move to southward. The relationships between the yields and Chl-a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between the catches of squid and longitude, but good with latitude.

  3. Isolation and Characterization of Collagen from Squid(Ommastreoges bartrami) Skin

    Institute of Scientific and Technical Information of China (English)

    YAN Mingyan; LI Bafang; ZHAO Xue

    2009-01-01

    Collagen of squid (Ommastrephes bartrami) skin was examined in the present study. Histology showed that collagen fiber in the skin was partially cross-linked with muscle fiber. Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin and characterized. The results of amino acid composition and electrophoretic patterns revealed that ASC and PSC were both type Ⅰ collagen, containing α1 and α2 chains. FTIR (fourier transform infrared spectroscopy) investigations con-firmed the existence of helical arrangements in PSC of squid skin. The denaturation temperature (Td) and shrinkage temperature (Ts)of PSC were 29.4℃ and 52.8℃, respectively.

  4. EFFECTS OF DIFFERENT REFINING METHODS ON THE MICRO-MORPHOLOGY, SPECTRA PROPERTIES AND METAL ELEMENTS OF MELANIN FROM SQUID ( OMMASTREPHES BARTRAM1) INK%不同精制方法对鱿鱼(Ommastrephes bartrami)墨黑色素的微观形态、光谱特征及金属元素的影响

    Institute of Scientific and Technical Information of China (English)

    宋茹; 李仁伟; 俞群娣; 邓尚贵

    2011-01-01

    采用扫描电镜、光谱分析和元素分析法,进行了胃蛋白酶水解法、高速离心法和酸水解法精制的鱿鱼墨黑色素颗粒形态、紫外可见光谱、红外光谱及金属元素含量的研究。结果表明,酸水解法破坏了鱿鱼墨黑色素的颗粒结构;三种不同精制方法所得的鱿鱼墨黑色素在220nm附近均有强吸收。胃蛋白酶水解和酸水解法有效切除黑色素的氨基基团,但酸水解法下鱿鱼墨黑色素吲哚类化合物的特征峰由1399.64cm-1移至1307.88cm-1;高速离心法精制的黑色素则在2925.02cm-1和2854.09cm-1有新吸收峰。不同精制方法对鱿鱼墨黑色素自身的不同金属元素含量具有降低和富集效应。%In this study, pepsin hydrolysis, high speed centrifugation and acidic hydrolysis were used to refine the melanin from squid (Ommastrephes bartrami) ink, and the characteristics of surface morphology, optical spectra and metal elements of these refined squid melanin were investigated. Results of scanning electronic microscope (SEM) showed that acidic hydrolysis damaged the melanin's original morphology. These refined squid melanin had maximum absorbance around 220nm. Fourier transform infra-red (FTIR) spectra revealed that pepsin hydrolysis and acidic hydrolysis cut off amino groups from squid melanin. However, the characteristic peak of indole group of melanin shifted from 1399.64cm-1 to 1307.88cm-1 after acidic hydrolysis. High speed centrifugation for squid melanin resulted in forming new peaks at 2925.02cm-1 and 2854.09cm-1, respectively. Moreover, the different refining methods lead to the effects of decrease or enrichment on the contents of metal elements in squid melanin.

  5. 巴特柔鱼(Ommastrephes bartrami)在不同贮藏温度下的鲜度变化%Freshness Variation of Ommastrephes bartrami during Storage at Different Temperature

    Institute of Scientific and Technical Information of China (English)

    黄洪亮; 郁岳峰; 冯春雷; 张勋; 周爱忠

    2007-01-01

    通过感官检定和理化检验,分析了不同贮藏温度(0℃、6~8℃和30℃)条件下巴特柔鱼的鲜度变化,结果表明:柔鱼内脏、墨汁最早影响柔鱼的TVBN值,柔鱼的背皮也是影响柔鱼TVBN的因素之一;在30℃的贮藏条件下,柔鱼鲜度的变化十分迅速,去内脏的柔鱼胴体6 h后其TVBN>30 mg/100 g,9 h后腐败;而柔鱼肌肉12 h后其TVBN>30 mg/100 g;在6~8℃和0℃的贮藏温度条件下,柔鱼肌肉的TVBN≤30 mg/100 g的放置时间分别为6 d和14 d.

  6. 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)

  7. 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.

  8. Role of Melanin in Oncogenesis

    Science.gov (United States)

    2011-08-01

    knockdown of individual enzymes that are specifically involved in melanin biosynthesis phenylalanine hydroxylase , tyrosinase, tyrosine hydroxylase and...with siRNAs directed against melanin biosynthetic enzymes, tyrosinase (siTYR), tyrosine hydroxylase (TYH), phenlyalanine hydroxylase (siPKU), and

  9. Photoacoustic measurement of epidermal melanin

    Science.gov (United States)

    Viator, John A.; Svaasand, Lars O.; Aguilar, Guillermo; Choi, Bernard; Nelson, J. Stuart

    2003-06-01

    Most dermatologic laser procedures must consider epidermal melanin, as it is a broadband optical absorber which affects subsurface fluence, effectively limiting the amount of light reaching the dermis and targeted chromophores. An accurate method for quantifying epidermal melanin content would aid clinicians in determining proper light dosage for therapeutic laser procedures. While epidermal melanin content has been quantified non-invasively using optical methods, there is currently no way to determine the melanin distribution in the epidermis. We have developed a photoacoustic probe that uses a Q-switched, frequency doubled Nd:YAG laser operating at 532nm to generate acoustic pulses in skin in vivo. The probe contained a piezoelectric element that detected photoacoustic waves which were then analyzed for epidermal melanin content, using a photoacoustic melanin index (PAMI). We tested 15 human subjects with skin types I--VI using the photoacoustic probe. We also present photoacoustic data for a human subject with vitiligo. Photoacoustic measurement showed melanin in the vitiligo subject was almost completely absent.

  10. Synthetic Melanin E-Ink.

    Science.gov (United States)

    Chang, Lingqian; Chen, Feng; Zhang, Xiaokang; Kuang, Tairong; Li, Mi; Hu, Jiaming; Shi, Junfeng; Lee, Ly James; Cheng, Huanyu; Li, Yiwen

    2017-05-17

    Extensive efforts have been devoted to the development of surfactant-free electronic ink (E-ink) with excellent display resolution for high-definition resolution display. Herein, we report the use of polydopamine-based synthetic melanin, a class of functional nanoparticles with similar chemical compositions and physical properties to those of naturally occurring melanin, as a new E-ink material. It was found that such E-ink displays could achieve ultrahigh resolution (>10 000 ppi) and low power consumption (operation voltage of only 1 V) in aqueous solutions. Interestingly, simple oxidation of synthetic melanin nanoparticles enables the generation of intrinsic fluorescence, allowing further development of fluorescent E-ink displays with nanoscale resolution. We describe these bioinspired materials in an initial proof-of-concept study and propose that synthetic melanin nanoparticles will be suitable for electronic nanoinks with a potential wide range of applications in molecular patterning and fluorescence bioimaging.

  11. Physical factors affecting chloroquine binding to melanin.

    Science.gov (United States)

    Schroeder, R L; Pendleton, P; Gerber, J P

    2015-10-01

    Chloroquine is an antimalarial drug but is also prescribed for conditions such as rheumatoid arthritis. Long-term users risk toxic side effects, including retinopathy, thought to be caused by chloroquine accumulation on ocular melanin. Although the binding potential of chloroquine to melanin has been investigated previously, our study is the first to demonstrate clear links between chloroquine adsorption by melanin and system factors including temperature, pH, melanin type, and particle size. In the current work, two Sepia melanins were compared with bovine eye as a representative mammalian melanin. Increasing the surface anionic character due to a pH change from 4.7 to 7.4 increased each melanin's affinity for chloroquine. Although the chloroquine isotherms exhibited an apparently strong interaction with each melanin, isosteric heat analysis indicated a competitive interaction. Buffer solution cations competed effectively at low surface coverage; chloroquine adsorption occurs via buffer cation displacement and is promoted by temperature-influenced secondary structure swelling.

  12. Study of Melanin Bleaching After Immunohistochemistry of Melanin-containing Tissues

    OpenAIRE

    2015-01-01

    Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3′-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium perman...

  13. Fungal melanins differ in planar stacking distances.

    Science.gov (United States)

    Casadevall, Arturo; Nakouzi, Antonio; Crippa, Pier R; Eisner, Melvin

    2012-01-01

    Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study we used X ray diffraction to analyze melanins derived from Cryptococcus neoformans, Aspergillus niger, Wangiella dermatitides and Coprinus comatus. Analysis of melanin in melanized C. neoformans encapsulated cells was precluded by the fortuitous finding that the capsular polysaccharide had a diffraction spectrum that was similar to that of isolated melanin. The capsular polysaccharide spectrum was dominated by a broad non-Bragg feature consistent with origin from a repeating structural motif that may arise from inter-molecular interactions and/or possibly gel organization. Hence, we isolated melanin from each fungal species and compared diffraction parameters. The results show that the inferred stacking distances of fungal melanins differ from that reported for synthetic melanin and neuromelanin, occupying intermediate position between these other melanins. These results suggest that all melanins have a fundamental diffracting unit composed of planar graphitic assemblies that can differ in stacking distance. The stacking peak appears to be a distinguishing universal feature of melanins that may be of use in characterizing these enigmatic pigments.

  14. Synthesis and assembly of fungal melanin.

    Science.gov (United States)

    Eisenman, Helene C; Casadevall, Arturo

    2012-02-01

    Melanin is a unique pigment with myriad functions that is found in all biological kingdoms. It is multifunctional, providing defense against environmental stresses such as ultraviolet (UV) light, oxidizing agents and ionizing radiation. Melanin contributes to the ability of fungi to survive in harsh environments. In addition, it plays a role in fungal pathogenesis. Melanin is an amorphous polymer that is produced by one of two synthetic pathways. Fungi may synthesize melanin from endogenous substrate via a 1,8-dihydroxynaphthalene (DHN) intermediate. Alternatively, some fungi produce melanin from L-3,4-dihydroxyphenylalanine (L-dopa). The detailed chemical structure of melanin is not known. However, microscopic studies show that it has an overall granular structure. In fungi, melanin granules are localized to the cell wall where they are likely cross-linked to polysaccharides. Recent studies suggest the fungal melanin may be synthesized in internal vesicles akin to mammalian melanosomes and transported to the cell wall. Potential applications of melanin take advantage of melanin's radioprotective properties and propensity to bind to a variety of substances.

  15. Impacts of climatic and marine environmental variations on the spatial distribution of Ommastrephes bartramii in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    YU Wei; CHEN Xinjun; YI Qian; GAO Guoping; CHEN Yong

    2016-01-01

    Ommastrephes bartramii is an ecologically dependent species and has great commercial values among the Asia-Pacific countries. This squid widely inhabits the North Pacific, one of the most dynamic marine environments in the world, subjecting to multi-scale climatic events such as the Pacific Decadal Oscillation (PDO). Commercial fishery data from the Chinese squid-jigging fleets during 1995-2011 are used to evaluate the influences of climatic and oceanic environmental variations on the spatial distribution of O. bartramii. Significant interannual and seasonal variability are observed in the longitudinal and latitudinal gravity centers (LONG and LATG) of fishing ground of O. bartramii. The LATG mainly occurred in the waters with the suitable ranges of environmental variables estimated by the generalized additive model. The apparent north-south spatial shift in the annual LATG appeares to be associated with the PDO phenomenon and is closely related to the sea surface temperature (SST) and sea surface height (SSH) on the fishing ground, whereas the mixed layer depth (MLD) might contribute limited impacts to the distribution pattern of O. bartramii. The warm PDO regimes tend to yield cold SST and low SSH, resulting in a southward shift of LATG, while the cold PDO phases provid warm SST and elevated SSH, resulting in a northward shift of LATG. A regression model is developed to help understand and predict the fishing ground distributions of O. bartramii and improve the fishery management.

  16. The effect of sea surface temperature increase on the potential habitat ofOmmastrephes bartramii in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    XU Jie; CHEN Xinjun; CHEN Yong; DING Qi; TIAN Siquan

    2016-01-01

    In the Northwest Pacific Ocean, the squid jigging fisheries from China, Japan and other countries and regions have targeted the west winter-spring cohort of neon flying squid (Ommastrephes bartramii) from August to November since the 1970s. This squid is a short-lived ecological opportunist with a life-span of about one year, and its population is labile and recruitment variability is driven by the environment or climate change. This variability provides a challenge for ones to forecast the key habitats affected by climate change. The catch data of O. bartramii from Chinese squid jigging fishery and the satellite-derived sea surface temperature (SST) data are used in the Northwest Pacific Ocean from August to November of 1998 to 2004, the SST preferences ofO. bartramiicorresponding to high values of catch per fishing day (CPUE) are determined and monthly potential habitats are predicted using a histogram analysis of the SST data. The possible changes in the potential habitats of O. bartramii in the Northwest Pacific Ocean are estimated under four climate change scenarios based on the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change, i.e., 0.5, 1, 2 and 4°C increases in the SST because of the climate change. The results reveal an obvious poleward shift of the potential habitats ofO. bartramii in the Northwest Pacific Ocean.

  17. Species identification of Ommastrephes bartramii, Dosidicus gigas, Sthenoteuthis oualaniensis and Illex argentinus (Ommastrephidae using beak morphological variables

    Directory of Open Access Journals (Sweden)

    Xinjun Chen

    2012-07-01

    Full Text Available Four oceanic squid species, Ommastrephes bartramii, Dosidicus gigas, Sthenoteuthis oualaniensis and Illex argentinus, not only support important commercial fisheries, but also play a vital role in their marine ecosystems. It is therefore important to identify them in the analyses of their predators’ stomach contents as this can yield critical information on the trophic dynamics of ecosystems. Hard beaks of the four species frequently found in their predators’ stomachs can be used to identify them. In this study, to remove the effect of size differences among individuals, measurements of upper and lower beaks were standardized with an allometric model. A discriminant analysis was carried out to compare morphological differences among the four species and between the sexes for each species. The upper rostral width and upper rostral length showed the greatest interspecific variation in the beak morphological variables of the four Ommastrephidae. The linear discriminant functions of beak morphological variables were developed for the four Ommastraphidae, which resulted in a rate of correct species classification of over 97%. Sexual dimorphism was also found in the beak morphology of O. bartramii and I. argentinus. This study suggests that morphological variables can be used to reliably classify Ommastrephidae at genus level, which can help identify the specie in the stomachs of cephalopod predators. This helps to improve the understanding of the role cephalopods play in their marine ecosystems.

  18. Modeling a habitat suitability index for the eastern fall cohort of Ommastrephes bartramii in the central North Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; TIAN Siquan; LIU Bilin; CHEN Yong

    2011-01-01

    The eastern fall cohort of the neon flying squid, Ommastrephes bartramii, has been commercially exploited by the Chinese squid jigging fleet in the central North Pacific Ocean since the late 1990s. To understand and identify their optimal habitat, we have developed a habitat suitability index (HSI) model using two potential important environmental variables - sea surface temperature (SST) and sea surface height anomaly (SSHA) - and fishery data from the main fishing ground (165°-180°E) during June and July of 1999-2003. A geometric mean model (GMM), minimum model (MM) and arithmetic weighted model (AWM) with different weights were compared and the best HSI model was selected using Akaike's information criterion (AIC). The performance of the developed HSI model was evaluated using fishery data for 2004. This study suggests that the highest catch per unit effort (CPUE) and fishing effort are closely related to SST and SSHA. The best SST- and SSHA-based suitability index (SI) regression models were SISST-bsed = 0.7SIeffort-SST + 0.3 SICPUE-SST, and SISSHA-based = 0.5SIeffon-SSHA + 0.5SICP,UE-SSHA,respectively, showing that fishing effort is more important than CPUE in the estimation of SI. The bestHSI model was the AWM, defined as HSI=0.3SISST-based+ 0.7SISSHA-based, indicating that SSHA is moreimportant than SST in estimating the HSI of squid. In 2004, monthly HSI values greater than 0.6 coincidedwith the distribution of productive fishing ground and high CPUE in June and July, suggesting that themodels perform well. The proposed model provides an important tool in our efforts to develop forecastingcapacity of squid spatial dynamics.

  19. Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae in the eastern Mediterranean and the implication on its range expansion

    Directory of Open Access Journals (Sweden)

    E. LEFKADITOU

    2012-12-01

    Full Text Available The neon flying squid Ommastrephes bartramii is found circumglobally in subtropical, temperate waters and sustains important fisheries in the North Pacific, but it is rarely encountered in the Mediterranean Sea. During the last decade, and particularly since 2004, the frequency of its presence in the Aegean Sea and nearby regions has increased, raising a question about a change in the species distribution and abundance in this area. In this study, we reviewed the literature on O. bartramii findings in the Mediterranean Sea and present new data describing body and beak morphometry, diet and the maturity of specimens recently collected from the easternmost basins. According to data from the entire Mediterranean Sea, collected individuals reached 66 cm in mantle length (ML, wherein only females were larger than 32 cm in ML. An isometric growth in body weight (BW was shown, whereas the lower beak rostral length (LRL was allometrically positive in relation to the ML. Occasional catches by jigs during experimental cruises provided most of the individuals recorded in the period from 1982-1992. In contrast, the most recent records are primarily comprised of mature females collected on or near the shore in the eastern basin and of predominantly smaller individuals from the western basin caught by professional jigging fisheries. The distribution of the specimen recorded from the Aegean Sea indicates an association between the species distribution and the circulation of the warm Levantine Intermediate Water. The more frequent observations of moribund spawning females at the periphery of the Cretan Sea are indicative of a spawning ground at this area. The suspected recent increase of O. bartramii abundance in both the northeastern and northwestern basins might be due to the warming of upper sea layers, which has been observed since the mid-1980s and is considered to be the main factor driving the northward expansion of the warm-water species’ range within

  20. Recent findings of Ommastrephes bartramii (Cephalopoda: Ommastrephidae in the eastern Mediterranean and the implication on its range expansion

    Directory of Open Access Journals (Sweden)

    E. LEFKADITOU

    2011-09-01

    Full Text Available The neon flying squid Ommastrephes bartramii is found circumglobally in subtropical, temperate waters and sustains important fisheries in the North Pacific, but it is rarely encountered in the Mediterranean Sea. During the last decade, and particularly since 2004, the frequency of its presence in the Aegean Sea and nearby regions has increased, raising a question about a change in the species distribution and abundance in this area. In this study, we reviewed the literature on O. bartramii findings in the Mediterranean Sea and present new data describing body and beak morphometry, diet and the maturity of specimens recently collected from the easternmost basins. According to data from the entire Mediterranean Sea, collected individuals reached 66 cm in mantle length (ML, wherein only females were larger than 32 cm in ML. An isometric growth in body weight (BW was shown, whereas the lower beak rostral length (LRL was allometrically positive in relation to the ML. Occasional catches by jigs during experimental cruises provided most of the individuals recorded in the period from 1982-1992. In contrast, the most recent records are primarily comprised of mature females collected on or near the shore in the eastern basin and of predominantly smaller individuals from the western basin caught by professional jigging fisheries. The distribution of the specimen recorded from the Aegean Sea indicates an association between the species distribution and the circulation of the warm Levantine Intermediate Water. The more frequent observations of moribund spawning females at the periphery of the Cretan Sea are indicative of a spawning ground at this area. The suspected recent increase of O. bartramii abundance in both the northeastern and northwestern basins might be due to the warming of upper sea layers, which has been observed since the mid-1980s and is considered to be the main factor driving the northward expansion of the warm-water species’ range within

  1. Spiders do have melanin after all.

    Science.gov (United States)

    Hsiung, Bor-Kai; Blackledge, Todd A; Shawkey, Matthew D

    2015-11-01

    Melanin pigments are broadly distributed in nature - from bacteria to fungi to plants and animals. However, many previous attempts to identify melanins in spiders were unsuccessful, suggesting that these otherwise ubiquitous pigments were lost during spider evolution. Yet, spiders exhibit many dark colours similar to those produced by melanins in other organisms, and the low solubility of melanins makes isolation and characterization difficult. Therefore, whether melanins are truly absent or have simply not yet been detected is an open question. Raman spectroscopy provides a reliable way to detect melanins in situ, without the need for isolation. In this study, we document the presence of eumelanin in diverse species of spiders using confocal Raman microspectroscopy. Comparisons of spectra with theoretically calculated data falsify the previous hypothesis that dark colours are produced solely by ommochromes in spiders. Our data indicate that melanins are present in spiders and further supporting that they are present in most living organisms. © 2015. Published by The Company of Biologists Ltd.

  2. Variations of oceanic fronts and their influence on the fishing grounds of Ommastrephes bartramii in the Northwest Pacific

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; TIAN Siquan; GUAN Wenjian

    2014-01-01

    Two predominant currents, the warm Kuroshio Current and the cold Oyashio Current, meet in the North-west Pacific Ocean. The dynamics of physical oceanographic structures in this region, including frontal zones and meandering eddies, result in a highly productive habitat that serves as a favorable feeding ground for various commercially important species. Neon flying squid, Ommastrephes bartramii, is an im-portant oceanic squid, which is widely distributed in the North Pacific Ocean. Based on the catch data col-lected by Chinese squid jigging fleets and relevant environmental data, including sea surface temperature (SST) and fronts (represented by gradients of SST and thermocline) during 1998-2009, the variations of oceanic fronts and their influence on the fishing grounds of O. bartramii were evaluated, and the differ-ences in distribution of fishing grounds of O. bartramii in 2000 and 2002 were compared by describing the differences in vertical temperature between 0-300 m. It was found that the preferred horizontal tem-perature gradient of SST for O. bartramii tended to be centered at 0.01-0.02°C/nm, which attracted nearly 80% of the total fishing effort, and the preferred horizontal temperature gradients at the 50 m and 105 m layers were mainly located at 0.01-0.03°C/nm, which accounted for more than 70%of the total fishing effort during August-October. The preferred vertical temperature gradient within the 0-50 m layer for O. bartramii tended to be centered at 0.15-0.25°C/m during August and September and at 0.10-0.15°C/m in October, implying that the mixed surface layer was distributed at depths of 0-50 m. It was concluded that the vertical temperature gradient was more important than the horizontal temperature gradient in playing a role in forming the fishing ground. The results improved our understanding of the spatial dynamics of the O. bartramii fishery.

  3. Detection of spatial hot spots and variation for the neon flying squid Ommastrephes bartramii resources in the northwest Pacific Ocean

    Science.gov (United States)

    Feng, Yongjiu; Chen, Xinjun; Liu, Yan

    2016-08-01

    With the increasing effects of global climate change and fishing activities, the spatial distribution of the neon flying squid (Ommastrephes bartramii) is changing in the traditional fishing ground of 150°-160°E and 38°-45°N in the northwest Pacific Ocean. This research aims to identify the spatial hot and cold spots (i.e. spatial clusters) of O. bartramii to reveal its spatial structure using commercial fishery data from 2007 to 2010 collected by Chinese mainland squid-jigging fleets. A relatively strongly-clustered distribution for O. bartramii was observed using an exploratory spatial data analysis (ESDA) method. The results show two hot spots and one cold spot in 2007 while only one hot and one cold spots were identified each year from 2008 to 2010. The hot and cold spots in 2007 occupied 8.2% and 5.6% of the study area, respectively; these percentages for hot and cold spot areas were 5.8% and 3.1% in 2008, 10.2% and 2.9% in 2009, and 16.4% and 11.9% in 2010, respectively. Nearly half (>45%) of the squid from 2007 to 2009 reported by Chinese fleets were caught in hot spot areas while this percentage reached its peak at 68.8% in 2010, indicating that the hot spot areas are central fishing grounds. A further change analysis shows the area centered at 156°E/43.5°N was persistent as a hot spot over the whole period from 2007 to 2010. Furthermore, the hot spots were mainly identified in areas with sea surface temperature (SST) in the range of 15-20°C around warm Kuroshio Currents as well as with the chlorophyll-a (chl-a) concentration above 0.3 mg/m3. The outcome of this research improves our understanding of spatiotemporal hotspots and its variation for O. bartramii and is useful for sustainable exploitation, assessment, and management of this squid.

  4. Detection of spatial hot spots and variation for the neon flying squid Ommastrephes bartramii resources in the northwest Pacific Ocean

    Science.gov (United States)

    Feng, Yongjiu; Chen, Xinjun; Liu, Yan

    2017-07-01

    With the increasing effects of global climate change and fishing activities, the spatial distribution of the neon flying squid ( Ommastrephes bartramii) is changing in the traditional fishing ground of 150°-160°E and 38°-45°N in the northwest Pacific Ocean. This research aims to identify the spatial hot and cold spots (i.e. spatial clusters) of O. bartramii to reveal its spatial structure using commercial fishery data from 2007 to 2010 collected by Chinese mainland squid-jigging fleets. A relatively strongly-clustered distribution for O. bartramii was observed using an exploratory spatial data analysis (ESDA) method. The results show two hot spots and one cold spot in 2007 while only one hot and one cold spots were identified each year from 2008 to 2010. The hot and cold spots in 2007 occupied 8.2% and 5.6% of the study area, respectively; these percentages for hot and cold spot areas were 5.8% and 3.1% in 2008, 10.2% and 2.9% in 2009, and 16.4% and 11.9% in 2010, respectively. Nearly half (>45%) of the squid from 2007 to 2009 reported by Chinese fleets were caught in hot spot areas while this percentage reached its peak at 68.8% in 2010, indicating that the hot spot areas are central fishing grounds. A further change analysis shows the area centered at 156°E/43.5°N was persistent as a hot spot over the whole period from 2007 to 2010. Furthermore, the hot spots were mainly identified in areas with sea surface temperature (SST) in the range of 15-20°C around warm Kuroshio Currents as well as with the chlorophyll- a (chl- a) concentration above 0.3 mg/m3. The outcome of this research improves our understanding of spatiotemporal hotspots and its variation for O. bartramii and is useful for sustainable exploitation, assessment, and management of this squid.

  5. Fourier transform infrared spectroscopy for sepia melanin

    CSIR Research Space (South Africa)

    Mbonyiryivuze, A

    2015-08-01

    Full Text Available intensively studied biomolecule systems such as nucleic acid, proteins and carbohydrates. Melanins have been reported to have a diverse number of functions in the biosystem, including photosensitization, metal ion chelation, photoprotection to absorb a broad...

  6. Actinobacterial melanins: current status and perspective for the future.

    Science.gov (United States)

    Manivasagan, Panchanathan; Venkatesan, Jayachandran; Sivakumar, Kannan; Kim, Se-Kwon

    2013-10-01

    Melanins are enigmatic pigments that are produced by a wide variety of microorganisms including several species of bacteria and fungi. Melanins are biological macromolecules with multiple important functions, yet their structures are not well understood. Melanins are frequently used in medicine, pharmacology, and cosmetics preparations. Melanins also have great application potential in agriculture industry. They have several biological functions including photoprotection, thermoregulation, action as free radical sinks, cation chelators, and antibiotics. Plants and insects incorporate melanins as cell wall and cuticle strengtheners, respectively. Actinobacteria are the most economically as well as biotechnologically valuable prokaryotes. However, the melanin properties are, in general, poorly understood. In this review an evaluation is made on the present state of research on actinobacterial melanins and its perspectives. The highlights include the production and biotechnological applications of melanins in agriculture, food, cosmetic and medicinal fields. With increasing advancement in science and technology, there would be greater demands in the future for melanins produced by actinobacteria from various sources.

  7. DOPA and DHN pathway orchestrate melanin synthesis in Aspergillus species.

    Science.gov (United States)

    Pal, Anuradha K; Gajjar, Devarshi U; Vasavada, Abhay R

    2014-01-01

    Melanins are high molecular weight hydrophobic pigments that have been studied for their role in the virulence of fungal pathogens. We investigated the amount and type of melanin in 20 isolates of Aspergillus spp.; A. niger (n = 3), A. flavus (n = 5), A. tamarii (n = 3), A. terreus (n = 3), A. tubingensis (n = 3), A. sydowii (n = 3). Aspergillus spp. were identified by sequencing the internal transcribed spacer (ITS) region. Extraction of melanin from culture filtrate and fungal biomass was done and followed by qualitative and quantitative analysis of melanin pigment. Ultraviolet (UV), Fourier transformed infrared (FT-IR), and electron paramagnetic resonance (EPR) spectra analyses confirmed the presence of melanin. The melanin pathway was studied by analyzing the effects of inhibitors; kojic acid, tropolone, phthalide, and tricyclazole. The results indicate that in A. niger and A. tubingensis melanin was found in both culture filtrate and fungal biomass. For A. tamarii and A. flavus melanin was extracted from biomass only, whereas melanin was found only in culture filtrate for A. terreus. A negligible amount of melanin was found in A. sydowii. The maximum amount of melanin from culture filtrate and fungal biomass was found in A. niger and A. tamarrii, respectively. The DOPA (3,4-dihydroxyphenylalanine) pathway produces melanin in A. niger, A. tamarii and A. flavus, whereas the DHN (1,8-dihydroxynaphthalene) pathway produces melanin in A. tubingensis and A. terreus. It can be concluded that the amount and type of melanin in aspergilli largely differ from species to species.

  8. Study of melanin bleaching after immunohistochemistry of melanin-containing tissues.

    Science.gov (United States)

    Shen, Hongwu; Wu, Wenqiao

    2015-04-01

    Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3'-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium permanganate bleaching and potassium dichromate bleaching clearly destroyed DAB, whereas TCCA bleaching had no significant effect on DAB. Therefore, neither potassium permanganate nor potassium dichromate is an ideal solution, whereas TCCA might be an ideal solution for melanin bleaching after the immunohistochemical staining of melanin-containing tissues. After immunostaining followed by TCCA bleaching, the melanin could be completely removed in all 120 malignant melanoma tissue sections. Compared with the control, the DAB intensity was clear, and the tissue structure and cellular nuclei were well maintained. It is worth noting that TCCA should be freshly prepared before each experiment, and used within 2 hours of its preparation. In addition, sections should not be incubated with TCCA for over 30 minutes.

  9. Thermohydrogel Containing Melanin for Photothermal Cancer Therapy.

    Science.gov (United States)

    Kim, Miri; Kim, Hyun Soo; Kim, Min Ah; Ryu, Hyanghwa; Jeong, Hwan-Jeong; Lee, Chang-Moon

    2016-12-01

    Melanin is an effective absorber of light and can extend to near infrared (NIR) regions. In this study, a natural melanin is presented as a photothermal therapeutic agent (PTA) because it provides a good photothermal conversion efficiency, shows biodegradability, and does not induce long-term toxicity during retention in vivo. Poloxamer solution containing melanin (Pol-Mel) does not show any precipitation and shows sol-gel transition at body temperature. After irradiation from 808 nm NIR laser at 1.5 W cm(-2) for 3 min, the photothermal conversion efficiency of Pol-Mel is enough to kill cancer cells in vitro and in vivo. The tumor growth of mice bearing CT26 tumors treated with Pol-Mel injection and laser irradiation is suppressed completely without recurrence postirradiation. All these results indicate that Pol-Mel can become an attractive PTA for photothermal cancer therapy.

  10. Evidence for a Melanin Cell Wall Component in Pneumocystis carinii

    OpenAIRE

    Icenhour, Crystal R.; Kottom, Theodore J.; Limper, Andrew H

    2003-01-01

    Fluorescein isothiocyanate-labeled monoclonal antibodies specific for fungal melanin were used in this study to visualize melanin-like components of the Pneumocystis carinii cell wall. A colorimetric enzyme assay confirmed these findings. This is the first report of melanin-like pigments in Pneumocystis.

  11. 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.

  12. Melanin biosynthesis pathway in Agaricus bisporus mushrooms

    NARCIS (Netherlands)

    Weijn, A.; Bastiaan-Net, S.; Wichers, H.J.; Mes, J.J.

    2013-01-01

    With the full genome sequence of Agaricus bisporus available, it was possible to investigate the genes involved in the melanin biosynthesis pathway of button mushrooms. Based on different BLAST and alignments, genes were identified in the genome which are postulated to be involved in this pathway.

  13. Melanin as an active layer in biosensors

    Directory of Open Access Journals (Sweden)

    Marina Piacenti da Silva

    2014-03-01

    Full Text Available 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.

  14. 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.

  15. 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.

  16. Epidermal melanin absorption in human skin

    Science.gov (United States)

    Norvang Nilsen, Lill T.; Fiskerstrand, Elisanne J.; Nelson, J. Stuart; Berns, Michael W.; Svaasand, Lars O.

    1996-01-01

    The principle of laser induced selective photothermolysis is to induced thermal damage to specific targets in such a manner that the temperature of the surrounding tissue is maintained below the threshold for thermal damage. The selectivity is obtained by selection of a proper wavelength and pulse duration. The technique is presently being used in the clinic for removal of port-wine stains. The presence of melanin in the epidermal layer can represent a limitation to the selectivity. Melanin absorption drops off significantly with increasing wavelength, but is significant in the entire wavelength region where the blood absorption is high. Treatment of port-wine stain in patients with high skin pigmentation may therefore give overheating of the epidermis, resulting in epidermal necrosis. Melanosomal heating is dependent on the energy and duration of the laser pulse. The heating mechanism for time scales less than typically 1 microsecond(s) corresponds to a transient local heating of the individual melanosomes. For larger time scales, heat diffusion out of the melanosomes become of increased importance, and the temperature distribution will reach a local steady state condition after typically 10 microsecond(s) . For even longer pulse duration, heat diffusing from neighboring melanosomes becomes important, and the temperature rise in a time scale from 100 - 500 microsecond(s) is dominated by this mechanism. The epidermal heating during the typical 450 microsecond(s) pulse used for therapy is thus dependent on the average epidermal melanin content rather than on the absorption coefficient of the individual melanosomes. This study will present in vivo measurements of the epidermal melanin absorption of human skin when exposed to short laser pulses (< 0.1 microsecond(s) ) from a Q-switched ruby laser and with long laser pulses (approximately 500 microsecond(s) ) from a free-running ruby laser or a long pulse length flashlamp pumped dye laser. The epidermal melanin

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

    Bacterial melanin, obtained from the mutant strain ofBacillus 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 controls. Behavior tests showed that compared to control rats, the time taken for instrumental conditioned relfex recovery was signiifcantly shorter and the ability to keep the balance on the rotating bar was signiifcantly better in bacterial melanin-treated rats. Histomor-phological tests showed that bacterial melanin promoted axon regeneration after sciatic nerve injury. These ifndings suggest that bacterial melanin exhibits neuroprotective effects on injured sciatic nerve, contributes to limb motor function recovery, and therefore can be used for rehabil-itation treatment of peripheral nerve injury.

  18. Melanins and melanogenesis: methods, standards, protocols.

    Science.gov (United States)

    d'Ischia, Marco; Wakamatsu, Kazumasa; Napolitano, Alessandra; Briganti, Stefania; Garcia-Borron, José-Carlos; Kovacs, Daniela; Meredith, Paul; Pezzella, Alessandro; Picardo, Mauro; Sarna, Tadeusz; Simon, John D; Ito, Shosuke

    2013-09-01

    Despite considerable advances in the past decade, melanin research still suffers from the lack of universally accepted and shared nomenclature, methodologies, and structural models. This paper stems from the joint efforts of chemists, biochemists, physicists, biologists, and physicians with recognized and consolidated expertise in the field of melanins and melanogenesis, who critically reviewed and experimentally revisited methods, standards, and protocols to provide for the first time a consensus set of recommended procedures to be adopted and shared by researchers involved in pigment cell research. The aim of the paper was to define an unprecedented frame of reference built on cutting-edge knowledge and state-of-the-art methodology, to enable reliable comparison of results among laboratories and new progress in the field based on standardized methods and shared information.

  19. Induction of melanin biosynthesis in Vibrio cholerae.

    OpenAIRE

    Coyne, V E; al-Harthi, L

    1992-01-01

    Vibrio cholerae synthesized the pigment melanin in response to specific physiological conditions that were stressful to the bacterium. Pigmentation was induced when V. cholerae was subjected to hyperosmotic stress in conjunction with elevated growth temperatures (above 30 degrees C). The salt concentration tolerated by V. cholerae was lowered by additional abiotic factors such as acidic starting pH of the growth medium and limitation of organic nutrients. Although the amount of toxin detected...

  20. Biochemical degradation of soil humic acids and fungal melanins

    Energy Technology Data Exchange (ETDEWEB)

    Zavgorodnyaya, Y.A.; Demin, V.V.; Kurakov, A.V. [Moscow MV Lomonosov State University, Moscow (Russian Federation). Dept. of Soil Science

    2002-07-01

    Studies were conducted to compare properties and biodegradation of fungal melanins from Aspergillus niger and Cladosporium cladosporiodes with those of humic acids from soils and brown coal. Compared to the humic acids the fungal melanins contained more functional groups, were less hydrophilic and had relatively high molecular weights. Under the conditions of incubation the melanins were found to be more readily degradable than the humic acids studied. The changes in elemental composition, optical parameters and the decrease of molecular weight, observed for both fungal melanins during degradation, made them more similar to soil humic acids.

  1. Dopamine-melanin nanofilms for biomimetic structural coloration.

    Science.gov (United States)

    Wu, Tong-Fei; Hong, Jong-Dal

    2015-02-09

    This article describes the formation of dopamine-melanin thin films (50-200 nm thick) at an air/dopamine solution interface under static conditions. Beneath these films, spherical melanin granules formed in bulk liquid phase. The thickness of dopamine-melanin films at the interface relied mainly on the concentration of dopamine solution and the reaction time. A plausible mechanism underlining dopamine-melanin thin film formation was proposed based on the hydrophobicity of dopamine-melanin aggregates and the mass transport of the aggregates to the air/solution interface as a result of convective flow. The thickness of the interfacial films increased linearly with the dopamine concentration and the reaction time. The dopamine-melanin thin film and granules (formed in bulk liquid phase) with a double-layered structure were transferred onto a solid substrate to mimic the (keratin layer)/(melanin granules) structure present in bird plumage, thereby preparing full dopamine-melanin thin-film reflectors. The reflected color of the thin-film reflectors depended on the film thickness, which could be adjusted according to the dopamine concentration. The reflectance of the resulted reflectors exhibited a maximal reflectance value of 8-11%, comparable to that of bird plumage (∼11%). This study provides a useful, simple, and low-cost approach to the fabrication of biomimetic thin-film reflectors using full dopamine-melanin materials.

  2. 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.

  3. Effects of environmental variations on the abundance of western winter-spring cohort of neon flying squid (Ommastrephes bartramii) in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    YU Wei; CHEN Xinjun; CHEN Yong; YI Qian; ZHANG Yang

    2015-01-01

    During 1995–2011, annual production of winter-spring cohort ofOmmastrephes bartramii for Chinese squid-jigging fishery has greatly fluctuated, which is closely related to the environmental conditions on the spawning and fishing grounds. To better understand how squid recruitment and abundance were influenced by ocean environmental conditions, biological and physical environmental variables including sea surface temperature (SST), SST anomaly (SSTA), chlorophylla (Chla) concentration and the Kuroshio Current were examined during years with the highest (1999), intermediate (2005), and lowest (2009) catches. Catch per unit effort (CPUE) of the squid-jigging vessels was used as an indicator of squid abundance. The results indicated that high SST and Chla concentration on the spawning ground in 1999 resulted in favorable incubation and feeding conditions for squid recruitment. Whereas the suitable spawning zone (SSZ) in 2009 shifted southward and coincided with low SST and Chla concentration, resulting in a reduction in the squid recruitment. The small difference of SSZ area in the three years suggested the SSZ provided limited influences on the variability in squid recruitment. Furthermore, high squid abundance in 1999 and 2005 was associated with warm SSTA on the fishing ground. While the cool SSTA on the fishing ground in 2009 contributed to adverse habitat for the squid, leading to extremely low abundance. It was inferred that strengthened intensity of the Kuroshio force generally yielded favorable environmental conditions forO. bartramii. Future research are suggested to focus on the fundamental research on the early life stage ofO. bartramii and mechanism of how the ocean-climate variability affects the squid abundance and spatial distribution by coupling physical model with squid biological process to explore transport path and abundance distribution.

  4. 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

  5. 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 re

  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. 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

  8. Interocular agreement in melanin and macular pigment optical density.

    NARCIS (Netherlands)

    Kanis, M.J.; Berendschot, T.T.J.M.; van Norren, D.

    2007-01-01

    Macular pigment (MP) and melanin possibly protect the macular area by absorbing blue light and acting as antioxidants. Because little is known about the interocular correlation of melanin, we determined its optical density (MOD) in both eyes of healthy subjects using fundus reflectometry. The measur

  9. 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.

  10. Electronic structure calculations of ESR parameters of melanin units.

    Science.gov (United States)

    Batagin-Neto, Augusto; Bronze-Uhle, Erika Soares; Graeff, Carlos Frederico de Oliveira

    2015-03-21

    Melanins represent an important class of natural pigments present in plants and animals that are currently considered to be promising materials for applications in optic and electronic devices. Despite their interesting properties, some of the basic features of melanins are not satisfactorily understood, including the origin of their intrinsic paramagnetism. A number of experiments have been performed to investigate the electron spin resonance (ESR) response of melanin derivatives, but until now, there has been no consensus regarding the real structure of the paramagnetic centers involved. In this work, we have employed electronic structure calculations to evaluate the ESR parameters of distinct melanin monomers and dimers in order to identify the possible structures associated with unpaired spins in this biopolymer. The g-factors and hyperfine constants of the cationic, anionic and radicalar structures were investigated. The results confirm the existence of at least two distinct paramagnetic centers in melanin structure, identifying the chemical species associated with them and their roles in electrical conductivity.

  11. Pigment Melanin: Pattern for Iris Recognition

    CERN Document Server

    Hosseini, Mahdi S; Soltanian-Zadeh, Hamid

    2009-01-01

    Recognition of iris based on Visible Light (VL) imaging is a difficult problem because of the light reflection from the cornea. Nonetheless, pigment melanin provides a rich feature source in VL, unavailable in Near-Infrared (NIR) imaging. This is due to biological spectroscopy of eumelanin, a chemical not stimulated in NIR. In this case, a plausible solution to observe such patterns may be provided by an adaptive procedure using a variational technique on the image histogram. To describe the patterns, a shape analysis method is used to derive feature-code for each subject. An important question is how much the melanin patterns, extracted from VL, are independent of iris texture in NIR. With this question in mind, the present investigation proposes fusion of features extracted from NIR and VL to boost the recognition performance. We have collected our own database (UTIRIS) consisting of both NIR and VL images of 158 eyes of 79 individuals. This investigation demonstrates that the proposed algorithm is highly s...

  12. Activation of Melanin Synthesis in Alternaria infectoria by Antifungal Drugs.

    Science.gov (United States)

    Fernandes, Chantal; Prados-Rosales, Rafael; Silva, Branca M A; Nakouzi-Naranjo, Antonio; Zuzarte, Mónica; Chatterjee, Subhasish; Stark, Ruth E; Casadevall, Arturo; Gonçalves, Teresa

    2015-12-28

    The importance of Alternaria species fungi to human health ranges from their role as etiological agents of serious infections with poor prognoses in immunosuppressed individuals to their association with respiratory allergic diseases. The present work focuses on Alternaria infectoria, which was used as a model organism of the genus, and was designed to unravel melanin production in response to antifungals. After we characterized the pigment produced by A. infectoria, we studied the dynamics of 1,8-dihydroxynaphthalene (DHN)-melanin production during growth, the degree of melanization in response to antifungals, and how melanization affected susceptibility to several classes of therapeutic drugs. We demonstrate that A. infectoria increased melanin deposition in cell walls in response to nikkomycin Z, caspofungin, and itraconazole but not in response to fluconazole or amphotericin B. These results indicate that A. infectoria activates DHN-melanin synthesis in response to certain antifungal drugs, possibly as a protective mechanism against these drugs. Inhibition of DHN-melanin synthesis by pyroquilon resulted in a lower minimum effective concentration (MEC) of caspofungin and enhanced morphological changes (increased hyphal balloon size), characterized by thinner and less organized A. infectoria cell walls. In summary, A. infectoria synthesizes melanin in response to certain antifungal drugs, and its susceptibility is influenced by melanization, suggesting the therapeutic potential of drug combinations that affect melanin synthesis.

  13. Binding characteristics of fluoroquinolones to synthetic levodopa melanin.

    Science.gov (United States)

    Ono, Chiho; Tanaka, Makoto

    2003-08-01

    To define the binding characteristics of fluoroquinolones to synthetic levodopa melanin, the binding of various drugs, including levofloxacin and ofloxacin, and positive controls (timolol and chloroquine), was investigated in-vitro. The affinity and capacity of the drug binding were calculated by Langmuir's adsorption isotherm. The affinity constant (K) and the binding capacity (r(max)) of levofloxacin were similar to those of timolol and much lower than those of chloroquine. Racemic ofloxacin and its enantiomers showed similar K and r(max), suggesting that the binding lacked stereoselectivity. The binding experiment with levofloxacin derivatives indicated that the basic nitrogen atom at position 7 of the quinolone ring, but not carboxyl group at position 3, would play a critical role in the interaction of fluoroquinolones with melanin. The melanin-drug complexes of levofloxacin and chloroquine were washed with neutral phosphate buffer, ethanol and 1 M HCl solution to explain the nature of the interaction of melanin with the drugs. Electrostatic forces mainly participate in the formation of the chloroquine-melanin complex, whereas van der Waals' and hydrophobic interactions are involved in the levofloxacin-melanin complex in addition to electrostatic forces. The interactions of various fluoroquinolones such as norfloxacin, enoxacin, sparfloxacin, ciprofloxacin and lomefloxacin with melanin were also studied. The results showed that the relative K value was: chloroquine approximately ciprofloxacin, sparfloxacin >/= lomefloxacin > timolol, levofloxacin approximately enoxacin, norfloxacin, and that the relative r(max) value was: norfloxacin, enoxacin >/= chloroquine, sparfloxacin > levofloxacin, ciprofloxacin, timolol, lomefloxacin. The fluoroquinolones vary in their affinity and capacity to bind with melanin, and ciprofloxacin and sparfloxacin showed a stronger interaction with melanin than the other fluoroquinolones studied.

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

    Science.gov (United States)

    Upadhyay, Srijana; Xu, Xinping; Lowry, David; Jackson, Jennifer C; Roberson, Robert W; Lin, Xiaorong

    2016-03-22

    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.

  15. Possible link between interannual variation of neon flying squid (Ommastrephes bartramii) abundance in the North Pacific and the climate phase shift in 1998/1999

    Science.gov (United States)

    Igarashi, Hiromichi; Ichii, Taro; Sakai, Mitsuo; Ishikawa, Yoichi; Toyoda, Takahiro; Masuda, Shuhei; Sugiura, Nozomi; Mahapatra, Kedarnath; Awaji, Toshiyuki

    2017-01-01

    The relationship between interannual variation in abundance of the autumn cohort of the neon flying squid (Ommastrephes bartramii) and ocean environmental changes in the central North Pacific was examined. We focused on the change in subsurface ocean state during the 1998/1999 climate shift. Changes in catch per unit effort (CPUE) of the neon flying squid derived from long-term driftnet survey was compared to that in ocean environments related to the feeding conditions of the squid. A four-dimensional variational (4D-VAR) ocean data assimilation product was used as an accurate estimate of the dynamic state in the North Pacific. Correlation analysis indicated that the squid CPUE was highly related with the Pacific Decadal Oscillation (PDO) in winter. In January, the correlation field with the entrainment rate (ENT), the proxy for the nutrient-rich water supply entering the mixed layer, showed a good agreement with the main spawning and nursery ground of the autumn cohort (MSNGAC). The nutrient-rich water supply in the MSNGAC in early winter was mainly induced by the deepening of the mixed layer forced by surface latent heat cooling and turbulent mixing, while the basin-scale wind stress curl and the horizontal advection were less affected. These results suggest that the amount of newly supplied nutrient-rich water mass in early winter could affect the primary productivity throughout the winter and the resultant feeding conditions of the juvenile squid. We assumed that this process would determine the stock levels of the neon flying squid in the following summer. We further attempted to reconstruct the changes in neon flying squid CPUE during 1994-2006 by applying regression analysis to several parameters. The result showed that ENT, surface and subsurface temperatures, and the PDO index in February were good predictors for estimating the squid CPUE time series. In addition, the subsurface temperature in the MSNGAC in the preceding autumn was also a good predictor

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

    OpenAIRE

    Srijana Upadhyay; Xinping Xu; David Lowry; Jennifer C. Jackson; Robert W. Roberson; Xiaorong Lin

    2016-01-01

    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 ...

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

    African Journals Online (AJOL)

    SERVER

    2006-02-16

    Feb 16, 2006 ... Key words: Rhodotorula glutinis, Escherichia coli, Melanin, Insecticidal Protein. INTRODUCTION ... proteinaceous crystals toxic to different insect larvae (Bulla ..... Gulex univitattus, Aedes aegypti and Culex pipens. Mosq.

  18. Morphological and chemical composition characterization of commercial sepia melanin

    CSIR Research Space (South Africa)

    Mbonyiryivuze, A

    2015-06-01

    Full Text Available of functions in the biosystem, including photosensitization, metal ion chelation, photoprotection to absorb a broad range of electromagnetic radiation, antibiotic, thermoregulation [6]. Melanins are found all over the body from the skin and blood...

  19. [Generation of superoxides during the interaction of melanins with oxygen].

    Science.gov (United States)

    Lapina, V A; Dontsov, A E; Ostrovskiĭ, M A

    1984-10-01

    The rate of nitroblue tetrazolium (NBT) reduction by dihydroxyphenylalanine-melanin, pheomelanin and retinal pigment epithelium melanosomes under aerobic conditions (pH 7.4) is low both in the dark and upon illumination, but increases drastically in the presence of cetyltrimethylammonium bromide (CTAB). Under these conditions, the light insignificantly stimulates NBT reduction (1.3-fold). The reaction is effectively inhibited by superoxide dismutase. This suggests that superoxide anions (O2-. are formed as intermediate reaction products in the course of NBT reduction by melanins. At alkaline values of pH (greater than or equal to 9.0), the O2-.-dependent reduction of NBT can also take place in the absence of CTAB. In contrast with oxidation of photoreduced riboflavin, the melanin oxidation by O2 cannot induce lipid peroxidation. It is concluded that O2-. generation via melanin oxidation of melanosomes occurs only under non-physiological conditions and can hardly take place in vivo.

  20. Melanin content in melanoma metastases affects the outcome of radiotherapy.

    Science.gov (United States)

    Brożyna, Anna A; Jóźwicki, Wojciech; Roszkowski, Krzysztof; Filipiak, Jan; Slominski, Andrzej T

    2016-04-05

    Melanin possess radioprotective and scavenging properties, and its presence can affect the behavior of melanoma cells, its surrounding environment and susceptibility to the therapy, as showed in vitro experiments. To determine whether melanin presence in melanoma affects the efficiency of radiotherapy (RTH) we evaluated the survival time after RTH treatment in metastatic melanoma patients (n = 57). In another cohort of melanoma patients (n = 84), the relationship between melanin level and pT and pN status was determined. A significantly longer survival time was found in patients with amelanotic metastatic melanomas in comparison to the melanotic ones, who were treated with either RTH or chemotherapy (CHTH) and RTH. These differences were more significant in a group of melanoma patients treated only with RTH. A detailed analysis of primary melanomas revealed that melanin levels were significantly higher in melanoma cells invading reticular dermis than the papillary dermis. A significant reduction of melanin pigmentation in pT3 and pT4 melanomas in comparison to pT1 and T2 tumors was observed. However, melanin levels measured in pT3-pT4 melanomas developing metastases (pN1-3, pM1) were higher than in pN0 and pM0 cases. The presence of melanin in metastatic melanoma cells decreases the outcome of radiotherapy, and melanin synthesis is related to higher disease advancement. Based on our previous cell-based and clinical research and present research we also suggest that inhibition of melanogenesis can improve radiotherapy modalities. The mechanism of relationship between melanogenesis and efficacy of RTH requires additional studies, including larger melanoma patients population and orthotopic, imageable mouse models of metastatic melanoma.

  1. Isolation of a novel strain of Aeromonas media producing high levels of DOPA-melanin and assessment of the photoprotective role of the melanin in bioinsecticide applications.

    Science.gov (United States)

    Wan, X; Liu, H M; Liao, Y; Su, Y; Geng, J; Yang, M Y; Chen, X D; Shen, P

    2007-12-01

    To isolate a bacterium that produces high yield of melanin and to examine the effect of this bacterial pigment on the efficacy of a bioinsecticide. A novel melanin-producing bacterium, designated as strain WS, was isolated from the East Lake, Wuhan, China. Taxonomic studies of this strain indicate that it belongs to Aeromonas media. Physicochemical analysis of the pigment produced by strain WS (melanin WS) suggests that it is the authentic 3,4-dihydroxyphenylalanine (DOPA)-melanin. This melanin and that produced by Pseudomonas maltophilia P28 (melanin P28) share many biophysical properties, but the yield of the melanin WS is significantly higher than that of the melanin P28. In addition, the melanin WS appears to be more effective in the protection of a bioinsecticide against ultraviolet (UV) or solar radiation. At the concentration of 10 ppm, the melanin P28 exhibited no photoprotective effect on the bioinsecticide against UV radiation; in contrast, 5 ppm of melanin WS displayed an obvious protective effect. Similarly, the melanin WS displayed more protective effect on the bioinsecticide against solar radiation than the melanin P28 did over a 4-day period, with the effect being more dramatic for the last 2 days. We have isolated a novel bacterial strain of A. media that produces high levels of melanin. The melanin produced by this strain offers effective photoprotection of a commercial bioinsecticide BTI against UV and solar radiation. Our study suggests that the melanin produced by our newly isolated A. media strain has the potential to be used as a general photoprotective agent for bioinsecticides.

  2. 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.

  3. [Intervention of nicotinamide on skin melanin genesis after UVA exposed].

    Science.gov (United States)

    Patam, Muhammad; Jin, Xi-peng; Zhang, Yu-bin; Pan, Jian-ying; Shen, Guang-zu

    2007-08-01

    To investigate the interference effect of nicotinamide on UVA-induced melanin genesis and melanin transport in human skin melanocyte. The optimum UVA dose expected to cause cell proliferation: 0.2 J/cm(2), nicotinamide was added immediately after the 0.2 J/cm(2) UVA exposure and the melanin content, cell cycles, cell apoptosis and mRNA express level were measured respectively. Melanin content in melanocytes was increased significantly after exposed to 0.2 J/cm(2) UVA. Melanin content in melanocytes was decreased after treatment with 10.0 mmol/ml nicotinamide following UVA exposure, but the cell cycles and the cell apoptosis rate were not significantly altered. mRNA express levels of TYR, TRP-1 were modulated by nicotinamide. Nicotinamide has more effect on decreasing melanin genesis after UVA exposure, nicotinamide also plays a role in modulating the mRNA express of TYR, TRP-1 gene. It is possible to consider nicotinamide as an efficient and safe sun screen to provide a certain level of protection for UVA exposed skin.

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

    Science.gov (United States)

    Galván, Ismael; Solano, Francisco

    2016-04-08

    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.

  5. Cd 2+ effect on free radicals in Cladosporium cladosporioides-melanin tested by EPR spectroscopy

    Science.gov (United States)

    Matuszczyk, Magdalena; Buszman, Ewa; Pilawa, Barbara; Witoszyńska, Teresa; Wilczok, Tadeusz

    2004-08-01

    Changes in free radicals system of Cladosporium cladosporioides-melanin and model DOPA-melanin caused by diamagnetic Cd 2+ ions were studied by electron paramagnetic resonance (EPR) spectroscopy. EPR line of eumelanin was mainly found in the spectrum of Cl.cl.-melanin. Cd 2+ ions increased o-semiquinone free radicals concentration in both natural and synthetic melanins. Cd 2+ broadened EPR lines of Cl.cl.-melanin in mycelium and the ions fastened spin-lattice relaxation processes. The narrower EPR lines and slower spin-lattice relaxation were obtained for DOPA-melanin-Cd 2+ complexes than for DOPA-melanin. Pheomelanin additionally existing in Cl.cl. samples was responsible for differences between the EPR data for Cl.cl. melanin and DOPA-melanin.

  6. Melanin Made by Dopamine Oxidation: Thin Films and Interactions with Polyelectrolyte Multilayers

    OpenAIRE

    Bernsmann, Falk

    2014-01-01

    The spontaneous oxidation of dopamine in slightly alkaline solutions was investigated on the basis of the work of Lee and others [Science, 318:426-430, 2007], and the reaction product was identified as dopamine-melanin. The ability of melanin to covalently bind amine functional groups was confirmed by quantification of the corresponding binding sites on dopamine-melanin aggregates. Furthermore it is possible to redissolve dopamine-melanin aggregates in strongly alkaline solutions. The obtaine...

  7. 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...

  8. 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

  9. diversion of the melanin synthetic pathway by dopamine product ...

    African Journals Online (AJOL)

    Studies have been reported about the physiological regulation of the ... However, the understanding of how melanin synthesis is regulated in the human body still needs ... conditions for temperature (298.15 K) and pressure (1.00 atm) using ...

  10. Paraquat-Melanin Redox-Cycling: Evidence from Electrochemical Reverse Engineering.

    Science.gov (United States)

    Kim, Eunkyoung; Leverage, W Taylor; Liu, Yi; Panzella, Lucia; Alfieri, Maria Laura; Napolitano, Alessandra; Bentley, William E; Payne, Gregory F

    2016-08-17

    Parkinson's disease is a neurodegenerative disorder associated with oxidative stress and the death of melanin-containing neurons of the substantia nigra. Epidemiological evidence links exposure to the pesticide paraquat (PQ) to Parkinson's disease, and this link has been explained by a redox cycling mechanism that induces oxidative stress. Here, we used a novel electrochemistry-based reverse engineering methodology to test the hypothesis that PQ can undergo reductive redox cycling with melanin. In this method, (i) an insoluble natural melanin (from Sepia melanin) and a synthetic model melanin (having a cysteinyldopamine-melanin core and dopamine-melanin shell) were entrapped in a nonconducting hydrogel film adjacent to an electrode, (ii) the film-coated electrode was immersed in solutions containing PQ (putative redox cycling reductant) and a redox cycling oxidant (ferrocene dimethanol), (iii) sequences of input potentials (i.e., voltages) were imposed to the underlying electrode to systematically engage reductive and oxidative redox cycling, and (iv) output response currents were analyzed for signatures of redox cycling. The response characteristics of the PQ-melanin systems to various input potential sequences support the hypothesis that PQ can directly donate electrons to melanin. This observation of PQ-melanin redox interactions demonstrates an association between two components that have been individually linked to oxidative stress and Parkinson's disease. Potentially, melanin's redox activity could be an important component in understanding the etiology of neurological disorders such as Parkinson's disease.

  11. Structural Characterization of Melanin Pigments from Commercial Preparations of the Edible Mushroom Auricularia auricula.

    Science.gov (United States)

    Prados-Rosales, Rafael; Toriola, Stacy; Nakouzi, Antonio; Chatterjee, Subhasish; Stark, Ruth; Gerfen, Gary; Tumpowsky, Paul; Dadachova, Ekaterina; Casadevall, Arturo

    2015-08-26

    Many of the most widely consumed edible mushrooms are pigmented, and these have been associated with some beneficial health effects. Nevertheless, the majority of the reported compounds associated with these desirable properties are non-pigmented. We have previously reported that melanin pigment from the edible mushroom Auricularia auricula can protect mice against ionizing radiation, although no physicochemical characterization was reported. Consequently, in this study we have characterized commercial A. auricula mushroom preparations for melanin content and carried out structural characterization of isolated insoluble melanin materials using a panel of sophisticated spectroscopic and physical/imaging techniques. Our results show that approximately 10% of the dry mass of A. auricula is melanin and that the pigment has physicochemical properties consistent with those of eumelanins, including hosting a stable free radical population. Electron microscopy studies show that melanin is associated with the mushroom cell wall in a manner similar to that of melanin from the model fungus C. neoformans. Elemental analysis of melanin indicated C, H, and N ratios consistent with 5,6-dihydroxyindole-2-carboxylic acid/5,6-dihydroxyindole and 1,8-dihydroxynaphthalene eumelanin. Validation of the identity of the isolated product as melanin was achieved by EPR analysis. A. auricula melanin manifested structural differences, relative to the C. neoformans melanin, with regard to the variable proportions of alkyl chains or oxygenated carbons. Given the necessity for new oral and inexpensive radioprotective materials coupled with the commercial availability of A. auricula mushrooms, this product may represent an excellent source of edible melanin.

  12. Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection.

    Science.gov (United States)

    Morris-Jones, Rachael; Youngchim, Sirida; Gomez, Beatriz L; Aisen, Phil; Hay, Roderick J; Nosanchuk, Joshua D; Casadevall, Arturo; Hamilton, Andrew J

    2003-07-01

    Melanin has been implicated in the pathogenesis of several important human fungal pathogens. Existing data suggest that the conidia of the dimorphic fungal pathogen Sporothrix schenckii produce melanin or melanin-like compounds; in this study we aimed to confirm this suggestion and to demonstrate in vitro and in vivo production of melanin by yeast cells. S. schenckii grown on Mycosel agar produced visibly pigmented conidia, although yeast cells grown in brain heart infusion and minimal medium broth appeared to be nonpigmented macroscopically. However, treatment of both conidia and yeast cells with proteolytic enzymes, denaturant, and concentrated hot acid yielded dark particles similar in shape and size to the corresponding propagules, which were stable free radicals consistent with identification as melanins. Melanin particles extracted from S. schenckii yeast cells were used to produce a panel of murine monoclonal antibodies (MAbs) which labeled pigmented conidia, yeast cells, and the isolated particles. Tissue from hamster testicles infected with S. schenckii contained fungal cells that were labeled by melanin-binding MAbs, and digestion of infected hamster tissue yielded dark particles that were also reactive. Additionally, sera from humans with sporotrichosis contained antibodies that bound melanin particles. These findings indicate that S. schenckii conidia and yeast cells can produce melanin or melanin-like compounds in vitro and that yeast cells can synthesize pigment in vivo. Since melanin is an important virulence factor in other pathogenic fungi, this pigment may have a similar role in the pathogenesis of sporotrichosis.

  13. 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.

  14. Keratinocyte-derived laminin-332 protein promotes melanin synthesis via regulation of tyrosine uptake.

    Science.gov (United States)

    Chung, Heesung; Jung, Hyejung; Lee, Jung-Hyun; Oh, Hye Yun; Kim, Ok Bin; Han, Inn-Oc; Oh, Eok-Soo

    2014-08-01

    Melanocytes, which produce the pigment melanin, are known to be closely regulated by neighboring keratinocytes. However, how keratinocytes regulate melanin production is unclear. Here we report that melanin production in melanoma cells (B16F10 and MNT-1) was increased markedly on a keratinocyte-derived extracellular matrix compared with a melanoma cell-derived extracellular matrix. siRNA-mediated reduction of keratinocyte-derived laminin-332 expression decreased melanin synthesis in melanoma cells, and laminin-332, but not fibronectin, enhanced melanin content and α-melanocyte-stimulating hormone-regulated melanin production in melanoma cells. Similar effects were observed in human melanocytes. Interestingly, however, laminin-332 did not affect the expression or activity of tyrosinase. Instead, laminin-332 promoted the uptake of extracellular tyrosine and, subsequently, increased intracellular levels of tyrosine in both melanocytes and melanoma cells. Taken together, these data strongly suggest that keratinocyte-derived laminin-332 contributes to melanin production by regulating tyrosine uptake.

  15. 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.

  16. 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.

  17. 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.

  18. Detection of antibodies against Paracoccidioides brasiliensis melanin in in vitro and in vivo studies during infection.

    Science.gov (United States)

    Urán, Martha E; Nosanchuk, Joshua D; Restrepo, Angela; Hamilton, Andrew J; Gómez, Beatriz L; Cano, Luz E

    2011-10-01

    Several cell wall constituents, including melanins or melanin-like compounds, have been implicated in the pathogenesis of a wide variety of microbial diseases caused by diverse species of pathogenic bacteria, fungi, and helminthes. Among these microorganisms, the dimorphic fungal pathogen Paracoccidioides brasiliensis produces melanin in its conidial and yeast forms. In the present study, melanin particles from P. brasiliensis were injected into BALB/c mice in order to produce monoclonal antibodies (MAbs). We identified five immunoglobulin G1 (IgG1) κ-chain and four IgM melanin-binding MAbs. The five IgG1 κ-chain isotypes are the first melanin-binding IgG MAbs ever reported. The nine MAbs labeled P. brasiliensis conidia and yeast cells both in vitro and in pulmonary tissues. The MAbs cross-reacted with melanin-like purified particles from other fungi and also with commercial melanins, such as synthetic and Sepia officinalis melanin. Melanization during paracoccidioidomycosis (PCM) was also further supported by the detection of IgG antibodies reactive to melanin from P. brasiliensis conidia and yeast in sera and bronchoalveolar lavage fluids from P. brasiliensis-infected mice, as well as in sera from human patients with PCM. Serum specimens from patients with other mycoses were also tested for melanin-binding antibodies by enzyme-linked immunosorbent assay, and cross-reactivities were detected for melanin particles from different fungal sources. These results suggest that melanin from P. brasiliensis is an immunologically active fungal structure that activates a strong IgG humoral response in humans and mice.

  19. 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.

  20. 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...

  1. Flavonoids and Melanins: a common strategy across two kingdoms.

    Science.gov (United States)

    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 free radical scavenging mechanisms. Both are phenol compounds constitutively synthesized and enhanced after exposure to UV rays, often conferring a red-brown-dark tissue pigmentation. Noteworthy, beside anti-oxidant scavenging activity, melanins and flavonoids have acquired secondary functions that, both in plants and animals, concern reproductions and fitness. Plants highly pigmented are more resistant to biotic and abiotic stresses. Darker wild vertebrates are generally more aggressive, sexually active and resistant to stress than lighter individuals. Flavonoids have been associated with signal attraction between flowers and insects and with plant-plant interaction. Melanin pigmentation has been proposed as trait in bird communication, acting as honest signals of quality. This review shows how the molecular mechanisms leading to tissue pigmentation have many functional analogies between plants and animals and how their origin lies in simpler organisms such as Cyanobacteria. Comparative studies between plant and animal kingdoms can reveal new insight of the antioxidant strategies in vivant.

  2. Genetic Basis of Melanin Pigmentation in Butterfly Wings.

    Science.gov (United States)

    Zhang, Linlin; Martin, Arnaud; Perry, Michael W; van der Burg, Karin R L; Matsuoka, Yuji; Monteiro, Antónia; Reed, Robert D

    2017-04-01

    Despite the variety, prominence, and adaptive significance of butterfly wing patterns, surprisingly little is known about the genetic basis of wing color diversity. Even though there is intense interest in wing pattern evolution and development, the technical challenge of genetically manipulating butterflies has slowed efforts to functionally characterize color pattern development genes. To identify candidate wing pigmentation genes, we used RNA sequencing to characterize transcription across multiple stages of butterfly wing development, and between different color pattern elements, in the painted lady butterfly Vanessa cardui This allowed us to pinpoint genes specifically associated with red and black pigment patterns. To test the functions of a subset of genes associated with presumptive melanin pigmentation, we used clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing in four different butterfly genera. pale, Ddc, and yellow knockouts displayed reduction of melanin pigmentation, consistent with previous findings in other insects. Interestingly, however, yellow-d, ebony, and black knockouts revealed that these genes have localized effects on tuning the color of red, brown, and ochre pattern elements. These results point to previously undescribed mechanisms for modulating the color of specific wing pattern elements in butterflies, and provide an expanded portrait of the insect melanin pathway. Copyright © 2017 by the Genetics Society of America.

  3. Sub-nm 3D observation of human hair melanin by high-voltage STEM.

    Science.gov (United States)

    Imai, Takehito; Higuchi, Kimitaka; Yamamoto, Yuta; Arai, Shigeo; Nakano, Takashi; Tanaka, Nobuo

    2016-04-01

    The ultrastructure of melanin granules in human hair was studied using 1,000 kV high-voltage scanning transmission electron microscopy to successfully reconstruct three-dimensional images of the whole melanin granule. It was revealed that the melanin granule was composed of a membrane-like outer structure that included many spherical vesicles, and an inner matrix containing a sheet-like structure in the elongated direction of the melanin granule and a sheet-like arrays structure in the cross direction. The outer structure of the melanin granule was maintained even after exposure to hair-bleaching agents to decompose the melanin granule, suggesting that the outer structure was a highly robust structure and composition compared with the inner matrix . © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

    Banerjee, Aulie; Supakar, Subhrangshu; Banerjee, Raja

    2014-01-01

    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 (13)C 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.

  5. 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 , Melanin Skin pigments • Melanin (epidermis), Haemoglobin (dermis), Bilirubin, Carotene, Keratin Melanocytes • Located at epidermal-dermal junction • Melanosomes • Melanin biosynthesis • In contact with ~ 40 keratinocytes Slide 4 of 41 © CSIR... due to keratin. More realistic phantoms – adding keratin • Comparison between the PheroidTM phantoms and melanosomes from different skin phototypes could not be made. To verify the true amount to which these phantoms represent real skin, such a...

  6. 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.

  7. Effect of pH on Paramagnetic Centers in Cladosporium cladosporioides Melanin

    Science.gov (United States)

    Pilawa, B.; Buszman, E.; Gondzik, A.; Wilczyński, S.; Zdybel, M.; Witoszyńska, T.; Wilczok, T.

    2006-07-01

    Paramagnetic centers in melanin existing in pigmented soil fungi Cladosporium cladosporioides cultured at acidic (4, 5, 6), neutral (7), and alkaline (8) pH were studied by EPR method. o-semiquinone free radicals (g: 2.0032-2.0040) concentration in melanin biopolymer increased for pH from 4 to 6, decreased at pH 7, and reached the maximum value at pH 8. It may be expected that melanin free radicals reactions with small molecules (metal ions, drugs) are the most effective at pH between 6 and 8. Slow spin-lattice relaxation processes exist in the all studied melanin samples.

  8. Production of natural edible melanin by Auricularia auricula and its physicochemical properties.

    Science.gov (United States)

    Sun, Shujing; Zhang, Xiaojuan; Chen, Wenxing; Zhang, Liaoyuan; Zhu, Hu

    2016-04-01

    Fermentation conditions of natural edible melanin by Auricularia auricula were optimized to obtain a high melanin yield and physicochemical properties of melanin were firstly investigated. The results indicated that yeast extract, tyrosine and lactose have significant effects on melanin production. Under the proposed optimized conditions, the melanin experimental yield (2.97 g/L) closely matched the value (3.04 g/L) predicted by the second-order model, which provided a statistically prediction of media in submerged fermentation of A. auricula. The yield achieved was 2.14-fold higher compared to the control. It was firstly revealed that tyrosine could stimulate melanin synthesis in A. auricula. The results showed that this melanin had better thermostability and light resistance, and its solubility was relatively high under alkaline conditions. Zn(2+) and Cu(2+) could result in melanin precipitation. The results should be useful for the efficient production of melanin and enable numerous applications in food, cosmetics, pharmacology, medicines and other fields.

  9. Production and cytotoxicity of extracellular insoluble and droplets of soluble melanin by Streptomyces lusitanus DMZ-3.

    Science.gov (United States)

    Madhusudhan, D N; Mazhari, Bi Bi Zainab; Dastager, Syed G; Agsar, Dayanand

    2014-01-01

    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.

  10. Isolation and characterization of biologically active melanin from Actinoalloteichus sp. MA-32.

    Science.gov (United States)

    Manivasagan, Panchanathan; Venkatesan, Jayachandran; Senthilkumar, Kalimuthu; Sivakumar, Kannan; Kim, Se-Kwon

    2013-07-01

    Melanins are enigmatic pigments and biological macromolecules that are produced by a wide variety of microorganisms including several species of bacteria and fungi. The present study was carried out on isolation and characterization of melanin from marine actinobacteria, Actinoalloteichus sp. MA-32. Medium composition and culture conditions for the melanin production by Actinoalloteichus sp. MA-32 were optimized using two statistical methods: Plackett-Burman design applied to find the key ingredients and conditions for the best yield of melanin production and central composite design used to optimize the concentration of the four significant variables: glycerol, L-tyrosine, NaCl and trace salt solution. The melanin was optimally active at pH 7-9 and temperature 45-60°C and it was most stable up to pH 11 and 4% of NaCl concentration. Melanin was examined by UV-vis absorption spectroscopy and infrared spectrometry. Melanin has potential antibacterial activity as it showed greater antagonistic and it has a strong antioxidant potential observed in the in vitro evaluation of its DPPH radical-scavenging activity, superoxide radical-scavenging activity, nitric oxide-scavenging activity, reducing power and metal chelating activity. The observed activities indicate that melanin might be a novel potential antioxidant. This study suggested that the melanin could potentially be used as a natural antioxidant in the food, cosmetic and pharmaceutical industries.

  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. 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

  13. From tyrosine to melanin: Signaling pathways and factors regulating melanogenesis

    Directory of Open Access Journals (Sweden)

    Zuzanna Rzepka

    2016-06-01

    Full Text Available Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI or 5,6-dihydroxyindole-2-carboxylic acid (DHICA. Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones. Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells.

  14. 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

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

    CSIR Research Space (South Africa)

    Karsten, AE

    2012-03-01

    Full Text Available -brown colour) and pheomelanin (yellow-reddish 11 colour) (3,4). Melanin is synthesized within melanosomes inside melanocytes located in the 12 basal layer of the epidermis and the mature melanosomes get transferred via dendrites to the 13 keratinocytes... in die epidermis where they are responsible for skin photoprotection (3). 14 It is well documented that the absorption and scattering of light through skin tissue 15 depends on the skin?s optical properties (see for example studies by Tuchin (5...

  16. Is there any difference in the photobiological properties of melanins isolated from human blue and brown eyes?

    Science.gov (United States)

    Menon, I A; Basu, P K; Persad, S; Avaria, M; Felix, C C; Kalyanaraman, B

    1987-01-01

    Investigations were carried out to determine whether the melanin present in the blue and brown eyes were eumelanin, the melanin present in black hair and dark skin, or pheomelanin, the melanin present in red hair and the skin of people with red hair. Our results showed that UV-visible irradiation of blue or brown eye melanin did not produce any superoxide. Irradiation of 51Cr-labelled Ehrlich ascites carcinoma cells in the presence of blue or brown eye melanin did not produce significant cell lysis. The electron spin resonance (ESR) signals of blue and brown eye melanins were very similar to those of eumelanin. Comparison of these findings with our previous results indicated that the blue and brown eye melanins are essentially eumelanin. The ESR signals further suggested that in the case of both blue and brown eye melanins the iris, ciliary body, choroid, and retinal pigment epithelium did not differ. PMID:2820463

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

    NARCIS (Netherlands)

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

    2012-01-01

    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.

  18. 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.

  19. 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.

  20. (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

  1. (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 cultur

  2. 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.

  3. 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. PMID:27031728

  4. 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.

  5. Color reduction of melanin by lysosomal and peroxisomal enzymes isolated from mammalian cells.

    Science.gov (United States)

    Park, Dong Jun; Sekhon, Simranjeet Singh; Yoon, Jihee; Kim, Yang-Hoon; Min, Jiho

    2016-02-01

    Lysosomes and peroxisomes are organelles with many functions in all eukaryotic cells. Lysosomes contain hydrolytic enzymes (lysozyme) that degrade molecules, whereas peroxisomes contain enzymes such as catalase that convert hydrogen peroxide (H2O2) to water and oxygen and neutralize toxicity. In contrast, melanin is known as a helpful element to protect the skin against harmful ultraviolet rays. However, a high quantity of melanin leads to hyperpigmentation or skin cancer in human. New materials have already been discovered to inhibit tyrosinase in melanogenesis; however, melanin reduction does not suggest their preparation. In this study, we report that the color intensity because of melanin decreased by the cellular activation of lysosomes and peroxisomes. An increase in the superficial intensity of lysosome and peroxisome activities of HeLa cells was observed. In addition, a decrease in the amount of melanin has also been observed in mammalian cells without using any other chemical, showing that the process can work in vivo for treating melanin. Therefore, the results of this study indicate that the amount of melanin decreases by the lysosome and peroxisome activity after entering the cells, and functional organelles are effective in color reduction. This mechanism can be used in vivo for treating melanin.

  6. Monte Carlo investigation on quantifying the retinal pigment epithelium melanin concentration by photoacoustic ophthalmoscopy.

    Science.gov (United States)

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

    2015-10-01

    The retinal pigment epithelium (RPE) melanin plays an important role in maintaining normal visual functions. A decrease in the RPE melanin concentration with aging is believed to be associated with several blinding diseases, including age-related macular degeneration. Quantifying the RPE melanin noninvasively is therefore important in evaluating the retinal health and aging conditions. Photoacoustic ophthalmoscopy (PAOM), as an optical absorption-based imaging technology, can potentially be applied to measure variations in the RPE melanin if the relationship between the detected photoacoustic (PA) signal amplitudes and the RPE melanin concentrations can be established. In this work, we tested the feasibility of using PA signals from retinal blood vessels as references to measure RPE melanin variation using Monte Carlo (MC) simulation. The influences from PAOM axial resolution, the depth and diameter of the retinal blood vessel, and the RPE thickness were examined. We proposed a calibration scheme by relating detected PA signals to the RPE melanin concentrations, and we found that the scheme is robust to these tested parameters. This study suggests that PAOM has the capability of quantitatively measuring the RPE melanin in vivo.

  7. 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.

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

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    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.

  9. Hesperetin induces melanin production in adult human epidermal melanocytes.

    Science.gov (United States)

    Usach, Iris; Taléns-Visconti, Raquel; Magraner-Pardo, Lorena; Peris, José-Esteban

    2015-06-01

    One of the major sources of flavonoids for humans are citrus fruits, hesperidin being the predominant flavonoid. Hesperetin (HSP), the aglycon of hesperidin, has been reported to provide health benefits such as antioxidant, anti-inflammatory and anticarcinogenic effects. However, the effect of HSP on skin pigmentation is not clear. Some authors have found that HSP induces melanogenesis in murine B16-F10 melanoma cells, which, if extrapolated to in vivo conditions, might protect skin against photodamage. Since the effect of HSP on normal melanocytes could be different to that observed on melanoma cells, the described effect of HSP on murine melanoma cells has been compared to the effect obtained using normal human melanocytes. HSP concentrations of 25 and 50 µM induced melanin synthesis and tyrosinase activity in human melanocytes in a concentration-dependent manner. Compared to control melanocytes, 25 µM HSP increased melanin production and tyrosinase activity 1.4-fold (p melanocyte cultures could be reproduced on human skin.

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

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    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.

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

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    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.

  12. 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

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

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    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.

  14. 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.

  15. Melanins: Skin Pigments and Much More—Types, Structural Models, Biological Functions, and Formation Routes

    Directory of Open Access Journals (Sweden)

    F. Solano

    2014-01-01

    Full Text Available This review presents a general view of all types of melanin in all types of organisms. Melanin is frequently considered just an animal cutaneous pigment and is treated separately from similar fungal or bacterial pigments. Similarities concerning the phenol precursors and common patterns in the formation routes are discussed. All melanins are formed in a first enzymatically-controlled phase, generally a phenolase, and a second phase characterized by an uncontrolled polymerization of the oxidized intermediates. In that second phase, quinones derived from phenol oxidation play a crucial role. Concerning functions, all melanins show a common feature, a protective role, but they are not merely photoprotective pigments against UV sunlight. In pathogenic microorganisms, melanization becomes a virulence factor since melanin protects microbial cells from defense mechanisms in the infected host. In turn, some melanins are formed in tissues where sunlight radiation is not a potential threat. Then, their redox, metal chelating, or free radical scavenging properties are more important than light absorption capacity. These pigments sometimes behave as a double-edged sword, and inhibition of melanogenesis is desirable in different cells. Melanin biochemistry is an active field of research from dermatological, biomedical, cosmetical, and microbiological points of view, as well as fruit technology.

  16. Experimental autoimmune anterior uveitis (EAAU): induction by melanin antigen and suppression by various treatments.

    Science.gov (United States)

    Broekhuyse, R M; Kuhlmann, E D; Winkens, H J

    1993-02-01

    The uveitogenicity of melanin has been a controversial subject for a long time, presumably as a result of the use of ill-defined preparations in the experiments. We have developed procedures for the preparation of purified uveitogenic melanins from the retinal pigment epithelium and choroid that are free from pathogenic retinal photoreceptor proteins. The active melano-antigen is located at the surface of the melanin granules and is probably identical in both tissues. It retains its pathogenicity in hot polar detergent and during in vitro proteolysis, but it is inactivated by macrophage phagocytosis and hydrolysis in hot hydrochloric acid. Lewis rats immunized with microgram doses of bovine retinal pigment epithelial or choroidal melanin develop severe experimental autoimmune anterior uveitis (EAAU) about 10 days later. Retinitis and pinealitis are not observed. Skin melanin prepared in a similar way evokes EAAU as well, but it is only weakly pathogenic. EAAU cannot be transferred by serum, and its development can effectively be inhibited by antibodies to the inciting antigen and by cyclosporin. Vitamin E treatment of the animals causes a delay in its onset. The results indicate that cell-mediated immunity plays a dominant role in the pathogenesis of EAAU. This is the first time it has been shown that purified ocular and skin melanins are able to induce an autoimmune disease. The relevance of this finding for the study of melanin-related immunopathology in man is discussed.

  17. Syndecan-2 regulates melanin synthesis via protein kinase C βII-mediated tyrosinase activation.

    Science.gov (United States)

    Jung, Hyejung; Chung, Heesung; Chang, Sung Eun; Choi, Sora; Han, Inn-Oc; Kang, Duk-Hee; Oh, Eok-Soo

    2014-05-01

    Syndecan-2, a transmembrane heparan sulfate proteoglycan that is highly expressed in melanoma cells, regulates melanoma cell functions (e.g. migration). Since melanoma is a malignant tumor of melanocytes, which largely function to synthesize melanin, we investigated the possible involvement of syndecan-2 in melanogenesis. Syndecan-2 expression was increased in human skin melanoma tissues compared with normal skin. In both mouse and human melanoma cells, siRNA-mediated knockdown of syndecan-2 was associated with reduced melanin synthesis, whereas overexpression of syndecan-2 increased melanin synthesis. Similar effects were also detected in human primary epidermal melanocytes. Syndecan-2 expression did not affect the expression of tyrosinase, a key enzyme in melanin synthesis, but instead enhanced the enzymatic activity of tyrosinase by increasing the membrane and melanosome localization of its regulator, protein kinase CβII. Furthermore, UVB caused increased syndecan-2 expression, and this up-regulation of syndecan-2 was required for UVB-induced melanin synthesis. Taken together, these data suggest that syndecan-2 regulates melanin synthesis and could be a potential therapeutic target for treating melanin-associated diseases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. 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.

  19. Fruit over sunbed: carotenoid skin colouration is found more attractive than melanin colouration.

    Science.gov (United States)

    Lefevre, Carmen E; Perrett, David I

    2015-01-01

    Skin colouration appears to play a pivotal part in facial attractiveness. Skin yellowness contributes to an attractive appearance and is influenced both by dietary carotenoids and by melanin. While both increased carotenoid colouration and increased melanin colouration enhance apparent health in Caucasian faces by increasing skin yellowness, it remains unclear, firstly, whether both pigments contribute to attractiveness judgements, secondly, whether one pigment is clearly preferred over the other, and thirdly, whether these effects depend on the sex of the face. Here, in three studies, we examine these questions using controlled facial stimuli transformed to be either high or low in (a) carotenoid colouration, or (b) melanin colouration. We show, firstly, that both increased carotenoid colouration and increased melanin colouration are found attractive compared to lower levels of these pigments. Secondly, we show that carotenoid colouration is consistently preferred over melanin colouration when levels of colouration are matched. In addition, we find an effect of the sex of stimuli with stronger preferences for carotenoids over melanin in female compared to male faces, irrespective of the sex of the observer. These results are interpreted as reflecting preferences for sex-typical skin colouration: men have darker skin than women and high melanization in male faces may further enhance this masculine trait, thus carotenoid colouration is not less desirable, but melanin colouration is relatively more desirable in males compared to females. Taken together, our findings provide further support for a carotenoid-linked health-signalling system that is highly important in mate choice.

  20. 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.

  1. Production of natural melanin by Auricularia auricula and study on its molecular structure.

    Science.gov (United States)

    Sun, Shujing; Zhang, Xiaojuan; Sun, Shiwei; Zhang, Liaoyuan; Shan, Shukai; Zhu, Hu

    2016-01-01

    In this study, the production and structure of melanin produced by Auricularia auricula have been determined and analyzed in detail. The results showed that the highest mycelial growth rate was observed in low-carbon and carbon-free medium. In low-nitrogen and nitrogen-free medium, melanin yield was very low. Deficiency of tyrosine in medium led to weak secretion of melanin. The inorganic salt could markedly influence mycelia morphology, but did not obviously impact mycelia growth rate and melanin yield. Meanwhile the condensed molecular formula ([C18(OR)3H7O4N2]n) and structural formula of melanin were concluded based on UV-Vis, HPLC, FTIR, NMR and elemental assay. This is an eumelanin and also a macromolecular polymer of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid. The 6 main components were phenolic hydroxyl, carboxyl, amidogen, carbonyl, methylene, methyne and sulfur. This work testified that nutritional control was very important to promote melanin production, making melanin more affordable as material in food, cosmetics and medicines.

  2. 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.

  3. Biologically derived melanin electrodes in aqueous sodium-ion energy storage devices.

    Science.gov (United States)

    Kim, Young Jo; Wu, Wei; Chun, Sang-Eun; Whitacre, Jay F; Bettinger, Christopher J

    2013-12-24

    Biodegradable electronics represents an attractive and emerging paradigm in medical devices by harnessing simultaneous advantages afforded by electronically active systems and obviating issues with chronic implants. Integrating practical energy sources that are compatible with the envisioned operation of transient devices is an unmet challenge for biodegradable electronics. Although high-performance energy storage systems offer a feasible solution, toxic materials and electrolytes present regulatory hurdles for use in temporary medical devices. Aqueous sodium-ion charge storage devices combined with biocompatible electrodes are ideal components to power next-generation biodegradable electronics. Here, we report the use of biologically derived organic electrodes composed of melanin pigments for use in energy storage devices. Melanins of natural (derived from Sepia officinalis) and synthetic origin are evaluated as anode materials in aqueous sodium-ion storage devices. Na(+)-loaded melanin anodes exhibit specific capacities of 30.4 ± 1.6 mAhg(-1). Full cells composed of natural melanin anodes and λ-MnO2 cathodes exhibit an initial potential of 1.03 ± 0.06 V with a maximum specific capacity of 16.1 ± 0.8 mAhg(-1). Natural melanin anodes exhibit higher specific capacities compared with synthetic melanins due to a combination of beneficial chemical, electrical, and physical properties exhibited by the former. Taken together, these results suggest that melanin pigments may serve as a naturally occurring biologically derived charge storage material to power certain types of medical devices.

  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.; 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.

  5. 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.

  6. 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

  7. Elemental characterisation of melanin in feathers via synchrotron X-ray imaging and absorption spectroscopy

    Science.gov (United States)

    Edwards, Nicholas P.; van Veelen, Arjen; Anné, Jennifer; Manning, Phillip L.; Bergmann, Uwe; Sellers, William I.; Egerton, Victoria M.; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Wakamatsu, Kazumasa; Ito, Shosuke; Wogelius, Roy A.

    2016-09-01

    Melanin is a critical component of biological systems, but the exact chemistry of melanin is still imprecisely known. This is partly due to melanin’s complex heterogeneous nature and partly because many studies use synthetic analogues and/or pigments extracted from their natural biological setting, which may display important differences from endogenous pigments. Here we demonstrate how synchrotron X-ray analyses can non-destructively characterise the elements associated with melanin pigment in situ within extant feathers. Elemental imaging shows that the distributions of Ca, Cu and Zn are almost exclusively controlled by melanin pigment distribution. X-ray absorption spectroscopy demonstrates that the atomic coordination of zinc and sulfur is different within eumelanised regions compared to pheomelanised regions. This not only impacts our fundamental understanding of pigmentation in extant organisms but also provides a significant contribution to the evidence-based colour palette available for reconstructing the appearance of fossil organisms.

  8. Characterization of melanin produced by a wild-type strain of Bacillus cereus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jianping; CAI Jun; DENG Yinyue; CHEN Yuehua; REN Gaixin

    2007-01-01

    Bacillus cereus 58 (Bc58)is a UV-resistant wild type strain that has an ability to produce a sorrel pigment induced by L-tyrosine.The Fourier-transform infrared (FT-IR)spectra and chemical tests of its pigment are similar to that of the standard melanin (Sigma).A bioassay shows that the LC50 of a Bacillus thuringiensis (Bt)formulation added with the melanin of Bc58 and exposed to UV for 5 h is 16.1 μg/ml,which is similar to that of the Bt formulation without UV treatment,however,it is almost double that of the Bt formulation exposed to UV without the melanin of Bc58.The result of SDS-PAGE indicates that the melanin of Bc58 can protect the insecticidal crystal proteins from degradation.This suggests that it is an excellent UV protective agent for the insecticidal crystal proteins of the Bt formulation.

  9. 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.

  10. Melanin concentrating hormone receptor 1 (MCHR1) antagonists - Still a viable approach for obesity treatment?

    DEFF Research Database (Denmark)

    Högberg, T.; Frimurer, T.M.; Sasmal, P.K.

    2012-01-01

    Obesity is a global epidemic associated with multiple severe diseases. Several pharmacotherapies have been investigated including the melanin concentrating hormone (MCH) and its receptor 1. The development of MCHR1 antagonists are described with a specific perspective on different chemotypes...

  11. Bio-Inspired Structural Colors Produced via Self-Assembly of Synthetic Melanin Nanoparticles.

    Science.gov (United States)

    Xiao, Ming; Li, Yiwen; Allen, Michael C; Deheyn, Dimitri D; Yue, Xiujun; Zhao, Jiuzhou; Gianneschi, Nathan C; Shawkey, Matthew D; Dhinojwala, Ali

    2015-05-26

    Structural colors arising from interactions of light with submicron scale periodic structures have been found in many species across all taxa, serving multiple biological functions including sexual signaling, camouflage, and aposematism. Directly inspired by the extensive use of self-assembled melanosomes to produce colors in avian feathers, we set out to synthesize and assemble polydopamine-based synthetic melanin nanoparticles in an effort to fabricate colored films. We have quantitatively demonstrated that synthetic melanin nanoparticles have a high refractive index and broad absorption spanning across the UV-visible range, similar to natural melanins. Utilizing a thin-film interference model, we demonstrated the coloration mechanism of deposited films and showed that the unique optical properties of synthetic melanin nanoparticles provide advantages for structural colors over other polymeric nanoparticles (i.e., polystyrene colloidal particles).

  12. Melanin and blood concentration in human skin studied by multiple regression analysis: experiments

    Science.gov (United States)

    Shimada, M.; Yamada, Y.; Itoh, M.; Yatagai, T.

    2001-09-01

    Knowledge of the mechanism of human skin colour and measurement of melanin and blood concentration in human skin are needed in the medical and cosmetic fields. The absorbance spectrum from reflectance at the visible wavelength of human skin increases under several conditions such as a sunburn or scalding. The change of the absorbance spectrum from reflectance including the scattering effect does not correspond to the molar absorption spectrum of melanin and blood. The modified Beer-Lambert law is applied to the change in the absorbance spectrum from reflectance of human skin as the change in melanin and blood is assumed to be small. The concentration of melanin and blood was estimated from the absorbance spectrum reflectance of human skin using multiple regression analysis. Estimated concentrations were compared with the measured one in a phantom experiment and this method was applied to in vivo skin.

  13. Natural melanin: a potential pH-responsive drug release device.

    Science.gov (United States)

    Araújo, Marco; Viveiros, Raquel; Correia, Tiago R; Correia, Ilídio J; Bonifácio, Vasco D B; Casimiro, Teresa; Aguiar-Ricardo, Ana

    2014-07-20

    This work proposes melanin as a new nanocarrier for pH-responsive drug release. Melanin is an abundant natural polymer that can be easily extracted from cuttlefish as nanoparticles with a suitable size range for drug delivery. However, despite its high potentiality, the application of this biopolymer in the pharmaceutical and biomedical fields is yet to be explored. Herein, melanin nanoparticles were impregnated with metronidazole, chosen as model antibiotic drug, using supercritical carbon dioxide. The drug release profile was investigated at acidic and physiologic pH, and the dominant mechanism was found to follow a non-Fickian transport. Drug release from melanin shows a strong pH dependency, which allied to its biocompatibility and lack of cytotoxicity envisages its potential application as nanocarrier in formulations for colon and intestine targeted drug delivery.

  14. Quick analysis of optical spectra to quantify epidermal melanin and papillary dermal blood content of skin.

    Science.gov (United States)

    Jacques, Steven L

    2015-04-01

    This paper presents a practical approach for assessing the melanin and blood content of the skin from total diffuse reflectance spectra, R(λ), where λ is wavelength. A quick spectral analysis using just three wavelengths (585 nm, 700 nm and 800 nm) is presented, based on the 1985 work of Kollias and Baquer who documented epidermal melanin of skin using the slope of optical density (OD) between 620 nm and 720 nm. The paper describes the non-rectilinear character of such a quick analysis, and shows that almost any choice of two wavelengths in the 600-900 range can achieve the characterization of melanin. The extrapolation of the melanin slope to 585 nm serves as a baseline for subtraction from the OD (585 nm) to yield a blood perfusion score. Monte Carlo simulations created spectral data for a skin model with epidermis, papillary dermis and reticular dermis to illustrate the analysis.

  15. Elemental characterisation of melanin in feathers via synchrotron X-ray imaging and absorption spectroscopy

    Science.gov (United States)

    Edwards, Nicholas P.; van Veelen, Arjen; Anné, Jennifer; Manning, Phillip L.; Bergmann, Uwe; Sellers, William I.; Egerton, Victoria M.; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Wakamatsu, Kazumasa; Ito, Shosuke; Wogelius, Roy A.

    2016-01-01

    Melanin is a critical component of biological systems, but the exact chemistry of melanin is still imprecisely known. This is partly due to melanin’s complex heterogeneous nature and partly because many studies use synthetic analogues and/or pigments extracted from their natural biological setting, which may display important differences from endogenous pigments. Here we demonstrate how synchrotron X-ray analyses can non-destructively characterise the elements associated with melanin pigment in situ within extant feathers. Elemental imaging shows that the distributions of Ca, Cu and Zn are almost exclusively controlled by melanin pigment distribution. X-ray absorption spectroscopy demonstrates that the atomic coordination of zinc and sulfur is different within eumelanised regions compared to pheomelanised regions. This not only impacts our fundamental understanding of pigmentation in extant organisms but also provides a significant contribution to the evidence-based colour palette available for reconstructing the appearance of fossil organisms. PMID:27658854

  16. 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.

  17. 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.

  18. 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.

  19. KHG26792 Inhibits Melanin Synthesis in Mel-Ab Cells and a Skin Equivalent Model

    OpenAIRE

    Li, Hailan; Kim, Jandi; Hahn, Hoh-Gyu; Yun, Jun; Jeong, Hyo-Soon; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Min, Young Sil; Park, Kyoung-Chan; Kim, Dong-Seok

    2014-01-01

    The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy) methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyros...

  20. An Ultra-Violet Tolerant Wild-Type Strain of Melanin-Producing Bacillus thuringiensis

    Science.gov (United States)

    Sansinenea, Estibaliz; Salazar, Francisco; Ramirez, Melanie; Ortiz, Aurelio

    2015-01-01

    Background: Bacillus thuringiensis is the most successful biological control agent used in agriculture, forestry and mosquito control. However, the insecticidal activity of the B. thuringiensis formulation is not very stable and rapidly loses its biological activity under field conditions, due to the ultraviolet radiation in sunlight. Melanin is known to absorb radiation therefore photo protection of B. thuringiensis based on melanin has been extensively studied. Objectives: The aim of this study was to find a wild type strain of naturally melanin-producing B. thuringiensis to avoid any mutation or manipulation that can affect the Cry protein content. Materials and Methods: Bacillus thuringiensis strains were isolated from soils of different States of Mexico and pigment extraction was followed by lowering the pH to 2 using 1N HCl. Pigment was characterized by some chemical tests based on its solubility, bleaching by H2O2 and flocculation with FeCl3, and using an Infrared (IR) spectrum. Ultraviolet (UV) irradiation experiment was performed to probe the melanin efficacy. Results: ELI52 strain of B. thuringiensis was confirmed to naturally produce melanin. The Cry protein analysis suggested that ELI52 is probably a B. thuringiensis subsp. israelensis strain with toxic activity against the Diptera order of insects. Ultra Violet protection efficacy of melanin was probed counting total viable colonies after UV radiation and comparing the results with the non-producing melanin strain L-DOPA (L-3, 4-dihydroxyphenylalanine) was also detected in the culture. ELI52 strain showed an antagonistic effect over some common bacteria from the environment. Conclusions: ELI52 wild-type strain of B. thuringiensis is a good bio-insecticide that produces melanin with UV-resistance that is probably toxic against the Diptera order of insects and can inhibit the growth of other environmental bacteria. PMID:26421136

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

    Science.gov (United States)

    Saino, Nicola; Romano, Maria; Rubolini, Diego; Teplitsky, Celine; Ambrosini, Roberto; Caprioli, Manuela; Canova, Luca; Wakamatsu, Kazumasa

    2013-01-01

    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, potentially

  2. Melanin, a promising radioprotector: mechanisms of actions in a mice model.

    Science.gov (United States)

    Kunwar, A; Adhikary, B; Jayakumar, S; Barik, A; Chattopadhyay, S; Raghukumar, S; Priyadarsini, K I

    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 50mg/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 (7Gy, 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.

  3. 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.

  4. 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.

  5. Manassantin A and B from Saururus chinensis inhibiting cellular melanin production.

    Science.gov (United States)

    Seo, Chang-Seob; Lee, Won-Hee; Chung, Hee-Wook; Chang, Eun Ju; Lee, Seung Ho; Jahng, Yurngdong; Hwang, Bang Yeon; Son, Jong-Keun; Han, Sang-Bae; Kim, Youngsoo

    2009-11-01

    Hyperpigmentation disorders such as freckles and senile lentigines in the skin are associated with abnormal accumulation of melanin pigments. In this study, two lignan constituents were isolated from Saururus chinensis Baill (Saururaceae) as inhibitors of cellular melanin production by bioassay-guided fractionations. The active constituents were manassantin A and B that dose-dependently inhibited melanin production in alpha-melanocyte stimulating hormone (alpha-MSH)-activated melanoma B16 cells with IC(50) values of 13 nm and 8 nm, respectively. Arbutin as a positive control exhibited an IC(50) value of 96 microm on alpha-MSH-induced melanin production. Further, manassantin A inhibited forskolin- or 3-isobutyl-1-methylxanthine (IBMX)-induced melanin production with IC(50) values of 14 nm or 12 nm, respectively. Manassantin A decreased cellular amounts of IBMX-inducible tyrosinase protein but could not affect the catalytic activity of cell-free tyrosinase, a key enzyme in the biosynthetic pathway of melanin pigments. Finally, this study could provide a pharmacological potential of S. chinensis in hyperpigmentation disorders.

  6. Production and Characterization of Melanin by Submerged Culture of Culinary and Medicinal Fungi Auricularia auricula.

    Science.gov (United States)

    Zhang, Min; Xiao, Gongnian; Thring, Ronald W; Chen, Wan; Zhou, Huabin; Yang, Hailong

    2015-05-01

    Natural melanin is of great potential value and application in the fields of pharmacology, cosmetics, and functional foods. In the present study, statistically designed experiments were conducted for the optimization of the media to enhance the production of melanin by submerged culture of Auricularia auricula. Glucose, tyrosine, peptone, and CaCO3 were found to have significant effects (P melanin biosynthesis by a Plackett-Burman experimental design and subsequently optimized using response surface methodology. Optimal media were obtained at the following concentrations: glucose, 0.90 g/L; tyrosine, 6.68 g/L; peptone, 6.99 g/L; and CaCO3, 6.75 g/L. The validity of the optimum media was verified in separate experiments in which the melanin yield of 1008.08 mg/L was obtained under optimum conditions, compared with 306.52 mg/L at other conditions, i.e., a 3.29-fold increase. Furthermore, the important physical and chemical properties of A. auricula melanin were determined. The findings from the present study indicate that large-scale production of natural melanin by submerged culture of A. auricular could be a useful approach.

  7. Preparation of melanin from Catharsius molossus L. and preliminary study on its chemical structure.

    Science.gov (United States)

    Xin, Chao; Ma, Jia-hua; Tan, Cheng-jia; Yang, Zhou; Ye, Feng; Long, Chan; Ye, Shuang; Hou, Da-bin

    2015-04-01

    A great deal of melanin was found in the waste alkali liquor produced by extraction of chitin from Catharsius molossus L. Discarding the lye could harm the environment and cause waste of resources. In this paper, melanin from C. molossus L. was recovered through acid precipitation and purified by pepsin and so on. The purity, chemical composition and structure of the prepared melanin were explored by UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, high resolution (13)C Cross polarization magic angle spinning nuclear magnetic resonance spectroscopy pyrolysis gas chromatography mass spectrometry, X ray diffraction, X ray fluorescence, matrix-assisted laser desorption/ionization time of flight tandem mass spectrometry, thermal analysis, and so on. The results showed that the purity of the prepared melanin was higher than the commercial standard melanin and it was a kind of nanoaggregates composed of a large quantity of 5,6-dihydroxyindole eumelanin and a small amount of phaeomelanin. In addition, the prepared melanin was irregular in shape and its structure could be divided into three levels: advanced structure maintained by polypeptides, substructure maintained by the ferric ion and microstructure. In particular, the smallest structural unit showed the graphite-like layered structure containing five layers linked by non-covalent bonds and each layer mainly consisted of 5,6-dihydroxyindole and its derivatives, which might be connected to each other through various chemical bonds.

  8. High-level production of melanin by a novel isolate of Streptomyces kathirae.

    Science.gov (United States)

    Guo, Jing; Rao, Zhiming; Yang, Taowei; Man, Zaiwei; Xu, Meijuan; Zhang, Xian

    2014-08-01

    Forty-five bacterial strains that produced diffusive pigments were isolated from 40 soil samples. Maximum pigment production was from a Streptomyces kathirae strain designated SC-1. The diffused pigment was characterized by UV-visual and infrared spectroscopy, MS and (1) H nuclear magnetic resonance imaging, and was confirmed as melanin. This may be the first report of melanin production by S. kathirae. To enhance melanin production, the culture medium was optimized by conducting a series of batch fermentations in a defined medium, and the results were analysed statistically using a response surface method. The optimal culture medium comprised 3.3 g L(-1) amylodextrine, 37 g L(-1) yeast extract, 5 g L(-1) NaCl, 0.1 g L(-1) CaCl2 and 54.4 μM CuSO4 . The pH of this medium was 6.0. Under optimal conditions, the melanin concentration was maximized at 13.7 g L(-1) , c. 8.6-fold higher than obtained in suboptimal medium. To our knowledge, the results provide novel data on melanin fermentation, and identify an excellent candidate for industrial-scale microbial fermentation of melanin.

  9. Characterization and biological activities of extracellular melanin produced by Schizophyllum commune (Fries).

    Science.gov (United States)

    Arun, G; Eyini, M; Gunasekaran, P

    2015-06-01

    Melanins are enigmatic pigments produced by a wide variety of microorganisms including bacteria and fungi. Here, we have isolated and characterized extracellular melanin from mushroom fungus, Schizophyllum commune. The extracellular dark pigment produced by the broth culture of S. commune, after 21 days of incubation was recovered by hot acid-alkali treatment. The melanin nature of the pigment was characterized by biochemical tests and further, confirmed by UV, IR, EPR, NMR and MALDI-TOF Mass Spectra. Extracellular melanin, at 100 μg/ml, showed significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens and antifungal activity against Trichophyton simii and T. rubrum. At a concentration of 50 μg/ml, melanin showed high free radical scavenging activity of DPPH (2,2-diphenyl-1-picrylhydrazyl) indicating its antioxidant potential. It showed concentration dependent inhibition of cell proliferation of Human Epidermoid Larynx Carcinoma Cell Line (HEP-2). This study has demonstrated characterization of melanin from basidiomycetes mushroom fungus, Schizophyllum commune and its applications.

  10. BmPAH catalyzes the initial melanin biosynthetic step in Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Ping Chen

    Full Text Available Pigmentation during insect development is a primal adaptive requirement. In the silkworm, melanin is the primary component of larval pigments. The rate limiting substrate in melanin synthesis is tyrosine, which is converted from phenylalanine by the rate-limiting enzyme phenylalanine hydroxylase (PAH. While the role of tyrosine, derived from phenylalanine, in the synthesis of fiber proteins has long been known, the role of PAH in melanin synthesis is still unknown in silkworm. To define the importance of PAH, we cloned the cDNA sequence of BmPAH and expressed its complete coding sequence using the Bac-to-Bac baculovirus expression system. Purified recombinant protein had high PAH activity, some tryptophan hydroxylase activity, but no tyrosine hydroxylase activity, which are typical properties of PAH in invertebrates. Because melanin synthesis is most robust during the embryonic stage and larval integument recoloring stage, we injected BmPAH dsRNA into silkworm eggs and observed that decreasing BmPAH mRNA reduced neonatal larval tyrosine and caused insect coloration to fail. In vitro cultures and injection of 4(th instar larval integuments with PAH inhibitor revealed that PAH activity was essential for larval marking coloration. These data show that BmPAH is necessary for melanin synthesis and we propose that conversion of phenylalanine to tyrosine by PAH is the first step in the melanin biosynthetic pathway in the silkworm.

  11. 北太平洋柔鱼渔业生物学研究进展%Review of fisheries biology of neon flying squid(Ommastrephes bartramii) in the North Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    马金; 陈新军; 刘必林; 田思泉; 李思亮; 曹杰

    2011-01-01

    柔鱼是重要的大洋性经济头足类,是我国远洋鱿钓渔船的主要捕捞对象。对北太平洋柔鱼的种群结构、洄游、年龄与生长、繁殖、摄食等生物学研究进展做了初步总结和归纳,并提出需要进一步深入研究的方向,供今后研究参考。柔鱼可分为4个季节性地理种群,即秋生东部群体、秋生中部群体、冬春生西部群体和冬春生中东部群体,但还需要在分子生物学角度得到进一步的确认;柔鱼随季节做南北洄游,其中向北索饵洄游模式研究较为深入,而向南产卵洄游模式尚不清楚,其产卵场空间分布及产卵期需要进一步调查;对柔鱼繁殖习性研究相对不足,尤其是产卵至孵化以及%Ommastrephes bartramii is an important economic cephalopod and also one of main fishing targets for Chinese squid jigging fleets.The knowledge of fishery biology is a basic condition for sustainable exploitation and utilization.The literature of population structure,migration,age and growth,spawning,feeding of O.bartramii has been reviewed,and comments and suggestion are provided in this paper.O.bartramii in the North Pacific Ocean can be sorted into four seasonal geographic cohorts,i.e.eastern stock of the fall cohort,central stock of the fall cohort,western stock of the winter-spring cohort and central-eastern stock of the winter-spring cohort.This classification need to be confirmed by the method of molecular biology.Generally,the squid made north-southward migration,the northward migration during the feeding period has been studied extensively;however the southward migration during spawning period was not clearly investigated,so the investigation on the temporal and spatial distribution of spawning ground is needed.Moreover,it is proposed that the spawning behavior of O.bartramii should be further studied,especially on the biologic process from spawning to hatching and paralarvae.The living environment of O.bartramii between west and

  12. Vaccinia virus-mediated melanin production allows MR and optoacoustic deep tissue imaging and laser-induced thermotherapy of cancer.

    Science.gov (United States)

    Stritzker, Jochen; Kirscher, Lorenz; Scadeng, Miriam; Deliolanis, Nikolaos C; Morscher, Stefan; Symvoulidis, Panagiotis; Schaefer, Karin; Zhang, Qian; Buckel, Lisa; Hess, Michael; Donat, Ulrike; Bradley, William G; Ntziachristos, Vasilis; Szalay, Aladar A

    2013-02-26

    We reported earlier the delivery of antiangiogenic single chain antibodies by using oncolytic vaccinia virus strains to enhance their therapeutic efficacy. Here, we provide evidence that gene-evoked production of melanin can be used as a therapeutic and diagnostic mediator, as exemplified by insertion of only one or two genes into the genome of an oncolytic vaccinia virus strain. We found that produced melanin is an excellent reporter for optical imaging without addition of substrate. Melanin production also facilitated deep tissue optoacoustic imaging as well as MRI. In addition, melanin was shown to be a suitable target for laser-induced thermotherapy and enhanced oncolytic viral therapy. In conclusion, melanin as a mediator for thermotherapy and reporter for different imaging modalities may soon become a versatile alternative to replace fluorescent proteins also in other biological systems. After ongoing extensive preclinical studies, melanin overproducing oncolytic virus strains might be used in clinical trials in patients with cancer.

  13. Non-toxic melanin production inhibitors from Garcinia livingstonei (Clusiaceae).

    Science.gov (United States)

    Mulholland, Dulcie A; Mwangi, Elizabeth M; Dlova, Ncoza C; Plant, Nick; Crouch, Neil R; Coombes, Phillip H

    2013-09-16

    The stem bark of Garcinia livingstonei is used traditionally as a skin lightening agent. To isolate and identify compounds responsible for the observed skin lightening activity of Garcinia livingstonei and to evaluate their cytotoxicity. Constituents of the stem bark and fruits of Garcinia livingstonei were isolated using chromatographic techniques and structures were determined using 1D and 2D NMR and MS analysis. MeWo cells were used to evaluate the cytotoxicity and impact on melanin levels of extracts and compounds isolated, in vitro. Twelve known compounds, morelloflavone (1), morelloflavone-7″-sulphate (2), guttiferone A (3), sargaol (4), isojacareubin (5), 6-deoxyisojacareubin (6) and in addition to the common triterpenoids, betulin, betulin aldehyde, lupeol, lupenone, euphol and stigmasterol were isolated in this investigation. Morelloflavone, morelloflavone-7″-sulphate and sargaol, were found to be considerably less cytotoxic and more effective as skin lightening agents than hydroquinone. A range of compounds was isolated from the stem bark and fruit of Garcinia livingstonei. Although the bark extract contained the cytotoxic guttiferone A, it was found to be less toxic than hydroquinone, and morelloflavone, the 7″-sulphate derivative and sargaol show potential for development as depigmentation/skin lightening agents. © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. 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.

  15. Redox activity of melanin from the ink sac of Sepia officinalis by means of colorimetric oxidative assay.

    Science.gov (United States)

    Srisuk, Pathomthat; Correlo, Vitor M; Leonor, Isabel B; Palladino, Pasquale; Reis, Rui L

    2016-01-01

    The redox properties of natural extract from cuttlefish ink sac (Sepia officinalis) and synthetic melanin used as a biomimetic in melanin structural investigation were determined by comparison of this phenol-based heterogeneous pigment with gallic acid used as a standard in Folin-Ciocalteu colorimetric assay widely employed for characterisation of oxidative properties of biomaterials. Reactivity of sepia melanin reported here is much higher than previously indicated and this protocol should allow the redox characterisation of all melanins irrespective of their origin and composition.

  16. Preparation of Thin Melanin-Type Films by Surface-Controlled Oxidation.

    Science.gov (United States)

    Salomäki, Mikko; Tupala, Matti; Parviainen, Timo; Leiro, Jarkko; Karonen, Maarit; Lukkari, Jukka

    2016-04-26

    The preparation of thin melanin films suitable for applications is challenging. In this work, we present a new alternative approach to thin melanin-type films using oxidative multilayers prepared by the sequential layer-by-layer deposition of cerium(IV) and inorganic polyphosphate. The interfacial reaction between cerium(IV) in the multilayer and 5,6-dihydroxyindole (DHI) in the adjacent aqueous solution leads to the formation of a thin uniform film. The oxidation of DHI by cerium(IV) proceeds via known melanin intermediates. We have characterized the formed DHI-melanin films using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), UV-vis spectroscopy, and spectroelectrochemistry. When a five-bilayer oxidative multilayer is used, the film is uniform with a thickness of ca. 10 nm. Its chemical composition, as determined using XPS, is typical for melanin. It is also redox active, and its oxidation occurs in two steps, which can be assigned to semiquinone and quinone formation within the indole structural motif. Oxidative multilayers can also oxidize dopamine, but the reaction stops at the dopamine quinone stage because of the limited amount of the multilayer-based oxidizing agent. However, dopamine oxidation by Ce(IV) was studied also in solution by UV-vis spectroscopy and mass spectrometry in order to verify the reaction mechanism and the final product. In solution, the oxidation of dopamine by cerium shows that the indole ring formation takes place already at low pH and that the mass spectrum of the final product is practically identical with that of commercial melanin. Therefore, layer-by-layer formed oxidative multilayers can be used to deposit functional melanin-type thin films on arbitrary substrates by a surface-controlled reaction.

  17. Melanin dependent survival of Apergillus fumigatus conidia in lung epithelial cells.

    Science.gov (United States)

    Amin, Shayista; Thywissen, Andreas; Heinekamp, Thorsten; Saluz, Hans Peter; Brakhage, Axel A

    2014-07-01

    Aspergillus fumigatus is the most important air-borne pathogenic fungus of humans. Upon inhalation of conidia, the fungus makes close contact with lung epithelial cells, which only possess low phagocytic activity. These cells are in particular interesting to address the question whether there is some form of persistence of conidia of A. fumigatus in the human host. Therefore, by also using uracil-auxotrophic mutant strains, we were able to investigate the interaction of A549 lung epithelial cells and A. fumigatus conidia in detail for long periods. Interestingly, unlike professional phagocytes, our study showed that the presence of conidial dihydroxynaphthalene (DHN) melanin enhanced the uptake of A. fumigatus conidia by epithelial cells when compared with non-pigmented pksP mutant conidia. Furthermore, conidia of A. fumigatus were able to survive within epithelial cells. This was due to the presence of DHN melanin in the cell wall of conidia, because melanised wild-type conidia showed a higher survival rate inside epithelial cells and led to inhibition of acidification of phagolysosomes. Both effects were not observed for white (non-melanised) conidia of the pksP mutant strain. Moreover, in contrast to pksP mutant conidia, melanised wild-type conidia were able to inhibit the extrinsic apoptotic pathway in A549 lung epithelial cells even for longer periods. The anti-apoptotic effect was not restricted to conidia, because both conidia-derived melanin ghosts (cell-free DHN melanin) and a different type of melanin, dihydroxyphenylalanine (DOPA) melanin, acted anti-apoptotically. Taken together, these data indicate the possibility of melanin-dependent persistence of conidia in lung epithelial cells.

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

    Science.gov (United States)

    Drewnowska, Justyna M; Zambrzycka, Monika; Kalska-Szostko, Beata; Fiedoruk, Krzysztof; Swiecicka, Izabela

    2015-01-01

    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.

  19. 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.

  20. Two-photon excited fluorescence lifetime imaging and spectroscopy of melanins in vitro and in vivo

    Science.gov (United States)

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

    2013-03-01

    Changes in the amounts of cellular eumelanin and pheomelanin have been associated with carcinogenesis. The goal of this work is to develop methods based on two-photon-excited-fluorescence (TPEF) for measuring relative concentrations of these compounds. We acquire TPEF emission spectra (λex=1000 nm) of melanin in vitro from melanoma cells, hair specimens, and in vivo from healthy volunteers. We find that the pheomelanin emission peaks at approximately 615 to 625 nm and eumelanin exhibits a broad maximum at 640 to 680 nm. Based on these data we define an optical melanin index (OMI) as the ratio of fluorescence intensities at 645 and 615 nm. The measured OMI for the MNT-1 melanoma cell line is 1.6±0.22 while the Mc1R gene knockdown lines MNT-46 and MNT-62 show substantially greater pheomelanin production (OMI=0.5±0.05 and 0.17±0.03, respectively). The measured values are in good agreement with chemistry-based melanin extraction methods. In order to better separate melanin fluorescence from other intrinsic fluorophores, we perform fluorescence lifetime imaging microscopy of in vitro specimens. The relative concentrations of keratin, eumelanin, and pheomelanin components are resolved using a phasor approach for analyzing lifetime data. Our results suggest that a noninvasive TPEF index based on spectra and lifetime could potentially be used for rapid melanin ratio characterization both in vitro and in vivo.

  1. Localization of melanin in conidia of Alternaria alternata using phage display antibodies.

    Science.gov (United States)

    Carzaniga, Raffaella; Fiocco, Daniela; Bowyer, Paul; O'Connell, Richard J

    2002-03-01

    Melanins derived from 1,8-dihydroxynaphthalene (DHN) are important for the pathogenicity and survival of fungi causing disease in both plants and animals. However, precise information on their location within fungal cell walls is lacking. To obtain antibodies for the immunocytochemical localization of melanin, 83 phage antibodies binding to 1,8-DHN were selected from a naive semisynthetic single-chain Fv (scFv) phage display library. Sequence analysis of the heavy chain binding domains of 17 antibodies showed a high frequency of positively charged amino acids. One antibody, designated M1, was characterized in detail. M1 bound specifically to 1,8-DHN in competitive inhibition enzyme-linked immunosorbent assays, showing no cross-reaction with nine structurally related phenolic compounds. Epitope recognition required two hydroxyl groups in a 1,8 configuration. M1 also bound to naturally occurring melanin isolated from mycelia of Alternaria alternata, suggesting that epitopes remain accessible in polymerized melanin. Transmission electron microscopy-immunogold labeling, using M1 in the form of soluble scFv fragments, showed that melanin was located in the septa and outer (primary) walls of wild-type A. alternata conidia, but not those of an albino mutant, AKT88-1. The M1 antibody provides a new tool for detecting melanized pathogens in plant and animal tissues and for precisely mapping the distribution of the polymer within spores, appressoria, and hyphae.

  2. A novel melanin inhibitor: hydroperoxy traxastane-type triterpene from flowers of Arnica montana.

    Science.gov (United States)

    Maeda, Kazuhisa; Naitou, Tomoko; Umishio, Kenichi; Fukuhara, Tadao; Motoyama, Akira

    2007-05-01

    We isolated a novel inhibitor of melanin biosynthesis from the flowers of Arnica montana L. (Compositae), and identified it as a traxastane-type triterpene (3beta,16beta-dihydroxy-21alpha-hydroperoxy-20(30)-taraxastene) [1] by means of 1D or 2D-NMR and liquid chromatography/high-resolution mass spectrometry (LC-HR-MS). Compound [1] at the concentration of 0.53 muM completely inhibited melanin accumulation in cultured B16 melanoma cells. It is one of the most potent among known plant inhibitors of melanin biosynthesis in cultured cells, being 50 times more potent than 4-methoxyphenol, which is used as an anti-pigmentation agent. Its mechanism of action is considered to involve inhibition of transcriptional factor MITF-M (melanocyte-type isoform of microphthalmia-associated transcription factor), which would lead to a decrease of tyrosinase and related genes. We confirmed that compound [1] decreased the protein levels of tyrosinase and its related proteins in B16 melanoma cells. Further study revealed that a similar hydroperoxy triterpene also suppressed the melanin pigment accumulation of B16 melanoma cells. These results indicate that the hydroperoxy group may play an important role in the suppression of the melanin accumulation by compound [1].

  3. Aspergillus Cell Wall Melanin Blocks LC3-Associated Phagocytosis to Promote Pathogenicity.

    Science.gov (United States)

    Akoumianaki, Tonia; Kyrmizi, Irene; Valsecchi, Isabel; Gresnigt, Mark S; Samonis, George; Drakos, Elias; Boumpas, Dimitrios; Muszkieta, Laetitia; Prevost, Marie-Christine; Kontoyiannis, Dimitrios P; Chavakis, Triantafyllos; Netea, Mihai G; van de Veerdonk, Frank L; Brakhage, Axel A; El-Benna, Jamel; Beauvais, Anne; Latge, Jean-Paul; Chamilos, Georgios

    2016-01-13

    Concealing pathogen-associated molecular patterns (PAMPs) is a principal strategy used by fungi to avoid immune recognition. Surface exposure of PAMPs during germination can leave the pathogen vulnerable. Accordingly, β-glucan surface exposure during Aspergillus fumigatus germination activates an Atg5-dependent autophagy pathway termed LC3-associated phagocytosis (LAP), which promotes fungal killing. We found that LAP activation also requires the genetic, biochemical or biological (germination) removal of A. fumigatus cell wall melanin. The attenuated virulence of melanin-deficient A. fumigatus is restored in Atg5-deficient macrophages and in mice upon conditional inactivation of Atg5 in hematopoietic cells. Mechanistically, Aspergillus melanin inhibits NADPH oxidase-dependent activation of LAP by excluding the p22phox subunit from the phagosome. Thus, two events that occur concomitantly during germination of airborne fungi, surface exposure of PAMPs and melanin removal, are necessary for LAP activation and fungal killing. LAP blockade is a general property of melanin pigments, a finding with broad physiological implications.

  4. Role of GTP-CHI links PAH and TH in melanin synthesis in silkworm, Bombyx mori.

    Science.gov (United States)

    Chen, Ping; Wang, Jiying; Li, Haiyin; Li, Yan; Chen, Peng; Li, Tian; Chen, Xi; Xiao, Junjie; Zhang, Liang

    2015-08-10

    In insects, pigment patterns are formed by melanin, ommochromes, and pteridines. Here, the effects of pteridine synthesis on melanin formation were studied using 4th instar larvae of a wild-type silkworm strain, dazao (Bombyx mori), with normal color and markings. Results from injected larvae and in vitro integument culture indicated that decreased activity of guanosine triphosphate cyclohydrolase I (GTP-CH I, a rate-limiting enzyme for pteridine synthesis), lowers BH4 (6R-l-erythro-5,6,7,8-tetrahydrobiopterin, a production correlated with GTP-CH I activity) levels and eliminates markings and coloration. The conversion of phenylalanine and tyrosine to melanin was prevented when GTP-CH I was inhibited. When BH4 was added, phenylalanine was converted to tyrosine, and the tyrosine concentration increased. Tyrosine was then converted to melanin to create normal markings and coloration. Decreasing GTP-CH I activity did not affect L-DOPA (3,4-l-dihydroxyphenylalanine). GTP-CH I affected melanin synthesis by generating the BH4 used in two key reaction steps: (1) conversion of phenylalanine to tyrosine by PAH (phenylalanine hydroxylase) and (2) conversion of tyrosine to L-DOPA by TH (tyrosine hydroxylase). Expression profiles of BmGTPCH Ia, BmGTPCH Ib, BmTH, and BmPAH in the integument were consistent with the current findings.

  5. Evolutionary shifts in the melanin-based color system of birds.

    Science.gov (United States)

    Eliason, Chad M; Shawkey, Matthew D; Clarke, Julia A

    2016-02-01

    Melanin pigments contained in organelles (melanosomes) impart earthy colors to feathers. Such melanin-based colors are distributed across birds and thought to be the ancestral color-producing mechanism in birds. However, we have had limited data on melanin-based color and melanosome diversity in Palaeognathae, which includes the flighted tinamous and large-bodied, flightless ratites and is the sister taxon to all other extant birds. Here, we use scanning electron microscopy and spectrophotometry to assess melanosome morphology and quantify reflected color for 19 species within this clade. We find that brown colors in ratites are uniquely associated with elongated melanosomes nearly identical in shape to those associated with black colors. Melanosome and color diversity in large-bodied ratites is limited relative to other birds (including flightless penguins) and smaller bodied basal maniraptoran dinosaur outgroups of Aves, whereas tinamous show a wider range of melanosome forms similar to neognaths. The repeated occurrence of novel melanosome forms in the nonmonophyletic ratites suggests that melanin-based color tracks changes in body size, physiology, or other life history traits associated with flight loss, but not feather morphology. We further anticipate these findings will be useful for future color reconstructions in extinct species, as variation in melanosome shape may potentially be linked to a more nuanced palette of melanin-based colors.

  6. Melanocyte biology and function with reference to oral melanin hyperpigmentation in HIV-seropositive subjects.

    Science.gov (United States)

    Feller, Liviu; Chandran, Rakesh; Kramer, Beverley; Khammissa, Razia A G; Altini, Mario; Lemmer, Johan

    2014-09-01

    The color of normal skin and of oral mucosa is not determined by the number of melanocytes in the epithelium but rather by their melanogenic activity. Pigmented biopolymers or melanins are synthesized in melanosomes. Tyrosinase is the critical enzyme in the biosynthesis of both brown/black eumelanin and yellow/red pheomelanin. The number of the melanosomes within the melanocytes, the type of melanin within the melanosomes, and the efficacy of the transfer of melanosomes from the melanocytes to the neighboring keratinocytes all play an important role in tissue pigmentation. Melanin production is regulated by locally produced factors including proopiomelanocortin and its derivative peptides, particularly alpha-melanocyte-stimulating hormone (α-MSH), melanocortin 1 receptor (MC1R), adrenergic and cholinergic agents, growth factors, cytokines, and nitric oxide. Both eumelanin and pheomelanin can be produced by the same melanocytes, and the proportion of the two melanin types is influenced by the degree of functional activity of the α-MSH/MC1R intracellular pathway. The cause of HIV oral melanosis is not fully understood but may be associated with HIV-induced cytokine dysregulation, with the medications commonly prescribed to HIV-seropositive persons, and with adrenocortical dysfunction, which is not uncommon in HIV-seropositive subjects with AIDS. The purpose of this article is to discuss some aspects of melanocyte biology and HIV-associated oral melanin hyperpigmentation.

  7. Melanin-containing films: growth from dopamine solutions versus layer-by-layer deposition.

    Science.gov (United States)

    Bernsmann, Falk; Ersen, Ovidiu; Voegel, Jean-Claude; Jan, Edward; Kotov, Nicholas A; Ball, Vincent

    2010-10-25

    Films formed by oxidation of dopamine are of interest for functionalisation of solid-liquid interfaces owing to their versatility. However, the ability to modulate the properties of such films, for example, permeability to ionic species and the absorption coefficient, is urgently needed. Indeed, melanin films produced by oxidation of dopamine absorb strongly over the whole UV/Vis part of the electromagnetic spectrum and are impermeable to anions even for a film thickness as low as a few nanometers. Herein we combine oxidation of dopamine to produce a solution containing dopamine-melanin particles and their alternating deposition with poly(diallyldimethylammonium chloride) to produce films which have nearly the same morphology as pure dopamine-melanin films but are less compact, more transparent and more permeable to ferrocyanide anions.

  8. 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.

  9. Experimentally induced melanin-like pigmentation (thesaurismosis) related to acorn ingestion in Nero Siciliano pigs.

    Science.gov (United States)

    Lanteri, Giovanni; Marino, Fabio; Liotta, Luigi; Stefano, Carmelo; Macrì, Battesimo

    2011-09-01

    In this study, an experimental challenge was carried out by feeding Nero Siciliano pigs with acorn to evoke melanin-like pigmentation and support the hypothesis that it is caused by ingested material. Twelve pigs were studied, 6 fed with acorns and 6 fed commercial feed. At slaughter, all the animals fed on acorns showed black discolouration of almost all lymph nodes. The lymph nodes were normal in size and shape. Histochemical tests performed on tissues allowed us to identify and differentiate the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Our data, and the well-known steps of melanin formation, confirm that swine enzymes could act on phenolic substances found in acorns.

  10. 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.

  11. 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.

  12. 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.

  13. Sexual selection and the function of a melanin-based plumage ornament in polygamous penduline tits Remiz pendulinus

    NARCIS (Netherlands)

    Kingma, Sjouke A.; Szentirmai, Istvan; Szekely, Tamas; Bokony, Veronika; Bleeker, Maarten; Liker, Andras; Komdeur, Jan; McGraw, K.

    2008-01-01

    Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly recognized. We investigated the functions of a melanin-based plumage ornament (facial 'mask') in male Eurasian penduline tits Remiz pendulinus in the contexts of male-

  14. Sexual selection and the function of a melanin-based plumage ornament in polygamous penduline tits Remiz pendulinus

    NARCIS (Netherlands)

    Kingma, Sjouke A.; Szentirmai, Istvan; Szekely, Tamas; Bokony, Veronika; Bleeker, Maarten; Liker, Andras; Komdeur, Jan; McGraw, K.

    2008-01-01

    Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly recognized. We investigated the functions of a melanin-based plumage ornament (facial 'mask') in male Eurasian penduline tits Remiz pendulinus in the contexts of male-

  15. 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. W

  16. 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

  17. 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.

  18. 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}.

  19. 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 synthes

  20. 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 (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.

  1. Innovative use of Mucuna monosperma (Wight) callus cultures for continuous production of melanin by using statistically optimized biotransformation medium.

    Science.gov (United States)

    Inamdar, Shrirang; Joshi, Swati; Bapat, Vishwas; Jadhav, Jyoti

    2014-01-20

    Melanins are predominantly indolic polymers which are having extensive applications in cosmetics, agriculture and medicine. In the present study, optimization of nutritional parameters influencing melanin production by Mucuna monosperma callus cultures was attempted using the response surface methodology (RSM). Standardization of four factors was carried out using the Box-Behnken design. The optimized levels of factors predicted by the model include tyrosine 0.978gL(-1), pH 5.85, SDS 34.55mgL(-1)and copper sulphate 21.14mgL(-1) tyrosine, which resulted in highest melanin yield of 0.887gL(-1). The optimization of medium using RSM resulted in a 3.06-fold increase in the yield of melanin. The ANOVA analysis showed a significant R(2)-value (0.9995), model F-value (1917.72) and probability (0.0001), with insignificant lack of fit. Optimized medium was used in the laboratory scale column reactor for the continuous production of melanin. Uninterrupted flow column exhibited maximum melanin production rate of 250mgL(-1)h(-1) which is the highest value ever reported using plant as a biotransformation source. Melanin production was confirmed by spectrophotometric and chemical analysis. Thus, this study demonstrates the production of melanin by M. monosperma callus, using a laboratory scale column reactor.

  2. 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.

  3. Tyrosine and the synthesis of melanin in embryonic cells fromAmbystoma mexicanum.

    Science.gov (United States)

    Landström, Ulf; Løvtrup, Søren

    1978-09-01

    Explants comprising about 15 cells were dissected from various regions of the blastula ofAmbystoma mexicanum and cultured in Barth's medium. By addition of L-tyrosine to the culture medium it was possible to induce melanin synthesis in three different cells types: undifferentiated embryonic cells, mesenchyme cells and nerve cells. Tyrosine was found to act as an inductor in a very low concentration (1 μM). It is suggested that tyrosine serves both as an inductor and as a substrate for melanin synthesis in the amphibian larva.

  4. 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.

  5. 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.

  6. 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; 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 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.

  7. 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.

    2015-01-01

    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 occipi

  8. 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 additio

  9. 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

  10. 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

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

    Directory of Open Access Journals (Sweden)

    Kamal Uddin Zaidi

    2016-01-01

    Full Text Available 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 tyrosinase absorption. Cellular tyrosinase activity and melanin content in B16F10 melanocytes were increased by purified tyrosinase in a dose-dependent manner. Western blot analysis revealed that cellular tyrosinase levels were enhanced after treatment with purified tyrosinase for 48 hours. Furthermore, tyrosinase induced phosphorylation of cyclic adenosine monophosphate (cAMP response element-binding protein (CREB in a dose-dependent manner. The purified tyrosinase-mediated increase of tyrosinase activity was significantly attenuated by H89, LY294002, Ro-32-0432, and PD98059, cAMP-dependent protein kinase inhibitors. The results indicate that purified tyrosinase can be used as contestant for the treatment of vitiligous skin conditions.

  12. Interpreting melanin-based coloration through deep time: a critical review

    Science.gov (United States)

    Lindgren, Johan; Moyer, Alison; Schweitzer, Mary H.; Sjövall, Peter; Uvdal, Per; Nilsson, Dan E.; Heimdal, Jimmy; Engdahl, Anders; Gren, Johan A.; Schultz, Bo Pagh; Kear, Benjamin P.

    2015-01-01

    Colour, derived primarily from melanin and/or carotenoid pigments, is integral to many aspects of behaviour in living vertebrates, including social signalling, sexual display and crypsis. Thus, identifying biochromes in extinct animals can shed light on the acquisition and evolution of these biological traits. Both eumelanin and melanin-containing cellular organelles (melanosomes) are preserved in fossils, but recognizing traces of ancient melanin-based coloration is fraught with interpretative ambiguity, especially when observations are based on morphological evidence alone. Assigning microbodies (or, more often reported, their ‘mouldic impressions’) as melanosome traces without adequately excluding a bacterial origin is also problematic because microbes are pervasive and intimately involved in organismal degradation. Additionally, some forms synthesize melanin. In this review, we survey both vertebrate and microbial melanization, and explore the conflicts influencing assessment of microbodies preserved in association with ancient animal soft tissues. We discuss the types of data used to interpret fossil melanosomes and evaluate whether these are sufficient for definitive diagnosis. Finally, we outline an integrated morphological and geochemical approach for detecting endogenous pigment remains and associated microstructures in multimillion-year-old fossils. PMID:26290071

  13. 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.

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

    Science.gov (United States)

    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 tyrosinase absorption. Cellular tyrosinase activity and melanin content in B16F10 melanocytes were increased by purified tyrosinase in a dose-dependent manner. Western blot analysis revealed that cellular tyrosinase levels were enhanced after treatment with purified tyrosinase for 48 hours. Furthermore, tyrosinase induced phosphorylation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) in a dose-dependent manner. The purified tyrosinase-mediated increase of tyrosinase activity was significantly attenuated by H89, LY294002, Ro-32-0432, and PD98059, cAMP-dependent protein kinase inhibitors. The results indicate that purified tyrosinase can be used as contestant for the treatment of vitiligous skin conditions. PMID:27699070

  15. Metal exposure influences the melanin and carotenoid-based colorations in great tits.

    Science.gov (United States)

    Giraudeau, M; Mateos-Gonzalez, F; Cotín, J; Pagani-Nuñez, E; Torné-Noguera, A; Senar, J C

    2015-11-01

    Metals are naturally found in the environment but are also emitted through anthropogenic activities, raising some concerns about the potential deleterious effects of these elements on wildlife. The potential effects of metals on bird coloration have been the focus of several recent studies since animal colored-signals often reflect the physiology of their bearers and are thus used by animals to assess the quality of another individual as a mate or competitor. These studies have shown that the melanin pigmentation seems to be positively associated and the carotenoid-based coloration negatively associated with metal exposure in wild birds. Although these studies have been very useful to show the associations between metal exposure and coloration, only few of them have actually quantified the levels of metal exposure at the individual level; always focusing on one or two of them. Here, we measured the concentrations of eight metals in great tits' feathers and then assessed how these levels of metals were associated with the carotenoid and melanin-based colorations. We found that the melanin pigmentation was positively associated with the copper concentration and negatively correlated with the chromium concentration in feathers. In addition, we have shown that the carotenoid-based coloration was negatively associated with the feather's mercury concentration. This study is the first one to identify some metals that might affect positively and negatively the deposition of melanin and carotenoid into the plumage of wild birds.

  16. Mechanistic insights into the bleaching of melanin by alkaline hydrogen peroxide.

    Science.gov (United States)

    Smith, R A W; Garrett, B; Naqvi, K R; Fülöp, A; Godfrey, S P; Marsh, J M; Chechik, V

    2017-07-01

    This work aims to determine the roles of reactive oxygen species HO∙ and HO2(-) in the bleaching of melanins by alkaline hydrogen peroxide. Experiments using melanosomes isolated from human hair indicated that the HO∙ radical generated in the outside solution does not contribute significantly to bleaching. However, studies using soluble Sepia melanin demonstrated that both HO2(-) and HO∙ will individually bleach melanin. Additionally, when both oxidants are present, bleaching is increased dramatically in both rate and extent. Careful experimental design enabled the separation of the roles and effects of these key reactive species, HO∙ and HO2(-). Rationalisation of the results presented, and review of previous literature, allowed the postulation of a simplified general scheme whereby the strong oxidant HO∙ is able to pre-oxidise melanin units to o-quinones enabling more facile ring opening by the more nucleophilic HO2(-). In this manner the efficiency of the roles of both species is maximised. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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.

  18. 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...

  19. Melanins and melanogenesis: from pigment cells to human health and technological applications.

    Science.gov (United States)

    d'Ischia, Marco; Wakamatsu, Kazumasa; Cicoira, Fabio; Di Mauro, Eduardo; Garcia-Borron, Josè Carlos; Commo, Stephane; Galván, Ismael; Ghanem, Ghanem; Kenzo, Koike; Meredith, Paul; Pezzella, Alessandro; Santato, Clara; Sarna, Tadeusz; Simon, John D; Zecca, Luigi; Zucca, Fabio A; Napolitano, Alessandra; Ito, Shosuke

    2015-09-01

    During the past decade, melanins and melanogenesis have attracted growing interest for a broad range of biomedical and technological applications. The burst of polydopamine-based multifunctional coatings in materials science is just one example, and the list may be expanded to include melanin thin films for organic electronics and bioelectronics, drug delivery systems, functional nanoparticles and biointerfaces, sunscreens, environmental remediation devices. Despite considerable advances, applied research on melanins and melanogenesis is still far from being mature. A closer intersectoral interaction between research centers is essential to raise the interests and increase the awareness of the biomedical, biomaterials science and hi-tech sectors of the manifold opportunities offered by pigment cells and related metabolic pathways. Starting from a survey of biological roles and functions, the present review aims at providing an interdisciplinary perspective of melanin pigments and related pathway with a view to showing how it is possible to translate current knowledge about physical and chemical properties and control mechanisms into new bioinspired solutions for biomedical, dermocosmetic, and technological applications.

  20. Near-infrared autofluorescence imaging of cutaneous melanins and human skin in vivo

    Science.gov (United States)

    Han, Xiao; Lui, Harvey; McLean, David I.; Zeng, Haishan

    2009-03-01

    In recent years, near-infrared (NIR) autofluorescence imaging has been explored as a novel technique for tissue evaluation and diagnosis. We present an NIR fluorescence imaging system optimized for the dermatologic clinical setting, with particular utility for the direct characterization of cutaneous melanins in vivo. A 785-nm diode laser is coupled into a ring light guide to uniformly illuminate the skin. A bandpass filter is used to purify the laser light for fluorescence excitation, while a long-pass filter is used to block the main laser wavelength but pass the spontaneous components for NIR reflectance imaging. A computer-controlled filter holder is used to switch these two filters to select between reflectance and fluorescence imaging modes. Both the reflectance and fluorescence photons are collected by an NIR-sensitive charge-coupled device (CCD) camera to form the respective images. Preliminary results show that cutaneous melanin in pigmented skin disorders emits higher NIR autofluorescence than surrounding normal tissue. This confirmed our previous findings from NIR fluorescence spectroscopy study of cutaneous melanins and provides a new approach to directly image the distributions of cutaneous melanins in the skin. In-vivo NIR autofluorescence images may be useful for clinical evaluation and diagnosis of pigmented skin lesions, including melanoma.

  1. 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

  2. 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.

  3. 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.

  4. Surface structure characterization of Aspergillus fumigatus conidia mutated in the melanin synthesis pathway and their human cellular immune response.

    Science.gov (United States)

    Bayry, Jagadeesh; Beaussart, Audrey; Dufrêne, Yves F; Sharma, Meenu; Bansal, Kushagra; Kniemeyer, Olaf; Aimanianda, Vishukumar; Brakhage, Axel A; Kaveri, Srini V; Kwon-Chung, Kyung J; Latgé, Jean-Paul; Beauvais, Anne

    2014-08-01

    In Aspergillus fumigatus, the conidial surface contains dihydroxynaphthalene (DHN)-melanin. Six-clustered gene products have been identified that mediate sequential catalysis of DHN-melanin biosynthesis. Melanin thus produced is known to be a virulence factor, protecting the fungus from the host defense mechanisms. In the present study, individual deletion of the genes involved in the initial three steps of melanin biosynthesis resulted in an altered conidial surface with masked surface rodlet layer, leaky cell wall allowing the deposition of proteins on the cell surface and exposing the otherwise-masked cell wall polysaccharides at the surface. Melanin as such was immunologically inert; however, deletion mutant conidia with modified surfaces could activate human dendritic cells and the subsequent cytokine production in contrast to the wild-type conidia. Cell surface defects were rectified in the conidia mutated in downstream melanin biosynthetic pathway, and maximum immune inertness was observed upon synthesis of vermelone onward. These observations suggest that although melanin as such is an immunologically inert material, it confers virulence by facilitating proper formation of the A. fumigatus conidial surface.

  5. Real-time in vivo confocal laser scanning microscopy of melanin-containing cells: A promising diagnostic intervention.

    Science.gov (United States)

    Xiang, Wenzhong; Song, Xiuzu; Peng, Jianzhong; Xu, Aie; Bi, Zhigang

    2015-12-01

    The use of noninvasive imaging techniques to evaluate different types of skin lesions is increasing popular. In vivo confocal laser scanning microscopy (CLSM) is a new method for high resolution non-invasive imaging of intact skin in situ and in vivo. Although many studies have investigated melanin-containing cells in lesions by in vivo CLSM, few studies have systematically characterized melanin-containing cells based on their morphology, size, arrangement, density, borders, and brightness. In this study, the characteristics of melanin-containing cells were further investigated by in vivo CLSM. A total of 130 lesions, including common nevi, giant congenital pigmented nevi, vitiligo, melasma, melanoma, and chronic eczema, were imaged by in vivo CLSM. This research helps dermatologists understand the characteristics of melanin-containing cells and facilitate the clinical application of melanin-containing cells in the investigation of dermatological disease. In summary, melanin-containing cells include keratinocytes, melanocytes, macrophages, and melanocytic skin tumor cells. Our study presents the CLSM characteristics of melanin-containing cells to potentially facilitate in vivo diagnosis based on shape, size, arrangement, density, borders, and brightness.

  6. Insulin-sensitizing and beneficial lipid-metabolic effects of the water-soluble melanin complex extracted from Inonotus obliquus.

    Science.gov (United States)

    Lee, Jung-Han; Hyun, Chang-Kee

    2014-09-01

    Inonotus obliquus has been traditionally used for treatment of metabolic diseases; however, the mechanism remains to be elucidated. In this study, we found that the water-soluble melanin complex extracted from I. obliquus improved insulin sensitivity and reduced adiposity in high fat (HF)-fed obese mice. When the melanin complex was treated to 3T3-L1 adipocytes, insulin-stimulated glucose uptake was increased significantly, and its phosphoinositide 3-kinase-dependent action was proven with wortmannin treatment. Additionally, dose-dependent increases in Akt phosphorylation and glucose transporter 4 translocation into the plasma membrane were observed in melanin complex-treated cells. Adiponectin gene expression in 3T3-L1 cells incubated with melanin complex increased which was corroborated by increased AMP-activated protein kinase phosphorylation in HepG2 and C2C12 cells treated with conditioned media from the 3T3-L1 culture. Melanin complex-treated 3T3-L1 cells showed no significant change in expression of several lipogenic genes, whereas enhanced expressions of fatty acid oxidative genes were observed. Similarly, the epididymal adipose tissue of melanin complex-treated HF-fed mice had higher expression of fatty acid oxidative genes without significant change in lipogenic gene expression. Together, these results suggest that the water-soluble melanin complex of I. obliquus exerts antihyperglycemic and beneficial lipid-metabolic effects, making it a candidate for promising antidiabetic agent.

  7. Role of melanin in release of extracellular enzymes and selection of aggressive isolates of Bipolaris sorokiniana in barley.

    Science.gov (United States)

    Chand, Ramesh; Kumar, Manoj; Kushwaha, Chanda; Shah, Kavita; Joshi, Arun K

    2014-08-01

    Eighteen barley isolates of Bipolaris sorokiniana belonging to wild and clonal type of black, mixed and white subpopulations were quantitatively assayed for their melanin content and aggressiveness with respect to production of some of the extracellular enzymes such as cellulase, pectinase, amylase and protease. Cellulase and pectinase constituted major portion of the enzymes recovered from the black, mixed and white isolates. Enzyme production and aggressiveness were relatively higher in melanin devoid or low melanin isolates. The melanin deficient isolates were also differentiated from black and mixed isolates on the basis of variation in internal transcribed spacer region of the ribosomal DNA. Higher enzyme productions positively correlated with area under disease progress curve (AUDPC) and lesion development. Melanin content was negatively correlated with extracellular enzymes and aggressiveness of the isolates. Based on melanin content, lesion size, AUDPC and extracellular enzymes, the isolates were grouped in two major clusters (I and II) with further division of cluster II into two sub-clusters (II-A and II-B). The results appears to indicate a possible role of melanin in release of extracellular enzymes and hence in evolution and selection of aggressive isolates of B. sorokiniana in barley.

  8. Melanin is required for the formation of the multi-cellular conidia in the endophytic fungus Pestalotiopsis microspora.

    Science.gov (United States)

    Yu, Xi; Huo, Liang; Liu, Heng; Chen, Longfei; Wang, Yu; Zhu, Xudong

    2015-10-01

    Melanin plays an important role in regulating various biological processes in many fungi. However, its biological role in conidiation remains largely elusive. We report here that conidia production, morphogenesis, integrity, germination and their viability in Pestalotiopsis microspora require the polyketide-derived melanin. A polyketide synthase gene, pks1, was identified and demonstrated responsible for melanin biosynthesis in this fungus. A targeted deletion mutant strain Δpks1 displayed a defect in pigmentation of conidia and had an albino colonial phenotype. Interestingly, Δpks1 produced approximately 6-fold as many conidia as the wild type did, suggesting a negative modulation of melanin on conidia production in this fungus. Moreover, the conidia failed to develop into the normal five-cell morphology, rather the three main-body cells separated via constriction at the original septum position to generate three independent mutant conidia. This result suggests a novel role of melanin in the formation of the multi-cellular conidia. Germ tubes could develop from the three different types of mutant conidia and kept elongating, despite a significantly lower germination rate was observed for them. Still more, the unpigmented conidia became permeable to Calcofluor White and DAPI, suggesting the integrity of the conidia was impaired. Deliberate inhibition of melanin biosynthesis by a specific inhibitor, tricyclazole, led to a similar phenotypes. This work demonstrates a new function of fungal melanin in conidial development.

  9. Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis.

    Science.gov (United States)

    Tarafder, Abul K; Bolasco, Giulia; Correia, Maria S; Pereira, Francisco J C; Iannone, Lucio; Hume, Alistair N; Kirkpatrick, Niall; Picardo, Mauro; Torrisi, Maria R; Rodrigues, Inês P; Ramalho, José S; Futter, Clare E; Barral, Duarte C; Seabra, Miguel C

    2014-04-01

    The transfer of melanin from melanocytes to keratinocytes is a crucial process underlying maintenance of skin pigmentation and photoprotection against UV damage. Here, we present evidence supporting coupled exocytosis of the melanin core, or melanocore, by melanocytes and subsequent endocytosis by keratinocytes as a predominant mechanism of melanin transfer. Electron microscopy analysis of human skin samples revealed three lines of evidence supporting this: (1) the presence of melanocores in the extracellular space; (2) within keratinocytes, melanin was surrounded by a single membrane; and (3) this membrane lacked the melanosomal membrane protein tyrosinase-related protein 1 (TYRP1). Moreover, co-culture of melanocytes and keratinocytes suggests that melanin exocytosis is specifically induced by keratinocytes. Furthermore, depletion of Rab11b, but not Rab27a, caused a marked decrease in both keratinocyte-stimulated melanin exocytosis and transfer to keratinocytes. Thus, we propose that the predominant mechanism of melanin transfer is keratinocyte-induced exocytosis, mediated by Rab11b through remodeling of the melanosome membrane, followed by subsequent endocytosis by keratinocytes.

  10. Unlocking the molecular structure of fungal melanin using 13C biosynthetic labeling and solid-state NMR.

    Science.gov (United States)

    Tian, Shiying; Garcia-Rivera, Javier; Yan, Bin; Casadevall, Arturo; Stark, Ruth E

    2003-07-15

    Melanins are enigmatic pigments found in all biological kingdoms that are associated with a variety of functions, including microbial virulence. Despite being ubiquitous in nature, melanin pigments have long resisted atomic-level structural examination because of their insolubility and amorphous organization. Cryptococcus neoformans is a human pathogenic fungus that melanizes only when provided with exogenous substrate, thus offering a unique system for exploring questions related to melanin structure at the molecular level. We have exploited the requirement for exogenous substrate in melanin synthesis as well as the capabilities of high-resolution solid-state nuclear magnetic resonance (NMR) to establish the predominantly aliphatic composition of l-dopa melanin and to introduce (13)C labels that permit the identification of proximal carbons in the developing biopolymer. By swelling solid melanin samples in organic solvents and using two-dimensional heteronuclear NMR in conjunction with magic-angle spinning, we have identified chemical bonding patterns typical of alkane, alkene, alcohol, ketone, ester, and indole functional groups. These findings demonstrate the feasibility of a novel approach to determining the structure of melanin using metabolic labeling and NMR spectroscopy.

  11. Melanin and Cryptococcus neoformans%黑素与新生隐球菌

    Institute of Scientific and Technical Information of China (English)

    王雪连; 孔庆涛; 王高峰; 刘芳; 邓德权; 桑红

    2011-01-01

    黑素的产生与多种微生物的毒力相关.新生隐球菌主要通过酚氧化酶(漆酶)合成黑素,黑素主要通过抵抗宿主微生物杀伤机制和影响宿主免疫应答来致病.主要就新生隐球菌黑素的微观结构、生物合成,漆酶的分子调节,黑素与新生隐球菌毒力的关系,黑化对真菌生存的影响及与抗真菌治疗的关系等方面进行概述,以期通过对黑素特征的理解为抗真菌药物的开发和对疾病的治疗策略选择提供帮助.%The production of melanin is associated with the virulence of various microorganisms.Cryptococcus neoformans produces melanin mainly via phenoloxidase(laccase)pathway.Melanin contributes to virulence likely by reducing the susceptibility of melanized fungi to host defense mechanisms and affecting immune responses in infected hosts.This review mainly focuses on the microstructure and biosynthesis of Cryptococcus neoformans melanin, molecular regulation of laecase, relationship between melanin and Cryptococcus neoformans virulence, effects of melanization on the survival of fungi, relationship between melanization and antifungal treatment, ete, which may facilitate the design and development of antifungal agents and strategies.

  12. 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.

  13. Characterization of human hair melanin and its degradation products by means of magnetic resonance techniques.

    Science.gov (United States)

    Ghiani, Simona; Baroni, Simona; Burgio, Daniela; Digilio, Giuseppe; Fukuhara, Masaki; Martino, Paola; Monda, Keiji; Nervi, Carlo; Kiyomine, Akira; Aime, Silvio

    2008-05-01

    Melanin granules (MGs) have been extracted from human Chinese black hairs by either acid hydrolysis (CH-type MGs) or enzymatic digestion (CP-type MGs), and their chemical structure investigated at the solid state by means of (13)C cross polarization magic angle spinning (CPMAS NMR) and EPR spectroscopy. Both types of MGs contain a large amount of protein that is tightly bound to the true melanin polymer, with CP-type MGs having a larger protein content than CH-type ones. Moreover, MGs may also contain variable amounts of lipid-like material. A high amount of paramagnetic metals is detected by EPR in CP-type MGs, in particular Fe(III). Iron can be bound in two chemical forms: as isolated high spin Fe(III) ions with rhombic symmetry and as small oxy-hydroxy Fe(III) aggregates. Iron is poorly available to chelators. CH-type MGs contain much fewer metals. CP-type MGs have then been subjected to partial bleaching by hydrogen peroxide in ammonia, yielding a residual solid, called residual oxidized melanin (ROM) and a soluble but still pigmented fraction called melanin free acid (MFA). MFA can be isolated by precipitation at acidic pH. The (13)C-CPMAS NMR and EPR spectra of these derivatives indicated that ROM has a structure very similar to that of parent MGs, whereas MFA shows a decrease of the protein content with respect to the melanin and a decreased amount of bound iron. Thus, the oxidative degradation of CP-type MGs is a process not involving the bulk of MGs, but rather it proceeds from the solvent-exposed outer parts to the interior. Copyright (c) 2008 John Wiley & Sons, Ltd.

  14. Brightness of melanin-based plumage coloration is a cue to oxidative stress in Himalayan Black Bulbuls (Hypsipete leucocephalus nigerrimus)

    Institute of Scientific and Technical Information of China (English)

    Hsin?Yi Hung; Shou?Hsien Li

    2015-01-01

    Background: Melanin?based coloration is often found to be associated with variations in physiological and behavio?ral traits that are essential in avian communication.However,the function of melanin?based traits to their bearers has been investigated less than that of carotenoid?based ones.It is commonly believed that expression of melanin?based pigmentation is genetically controlled.However,whether it could be modulated by physical condition has remained controversial.In this study,we demonstrate that the level of melanin?based plumage pigmentation could be nega?tively correlated with an individual’s oxidative stress level.Methods: In this study,we used two groups of Black Bulbuls(Hypsipetes leucocephalus nigerrimus) obtained from a pet?shop in 2010 and 2011 to examine the correlation between the melanin?based plumage coloration and the ratio of lymphocytes to heterocytes,which is an indicator of the oxidative stress experienced by an individual.Results: We found a negative correlation between oxidative stress levels and expression of melanin?based pigmen?tation on the breast and scapular feathers,but the correlation only appeared in the 2011 group,individuals of which had higher oxidative stress level and brighter plumage(i.e.more melanins) than those of the 2010 group.Conclusions: Our data suggest that melanin?based plumage could reflect an individual’s physical condition in certain situations.Therefore,melanin?based plumage coloration could have a function in Himalayan Black Bulbuls’ communication.

  15. Melanin directly converts light for vertebrate metabolic use: heuristic thoughts on birds, Icarus and dark human skin.

    Science.gov (United States)

    Goodman, Geoffrey; Bercovich, Dani

    2008-08-01

    Pigments serve many visually obvious animal functions (e.g. hair, skin, eyes, feathers, scales). One is 'melanin', unusual in an absorption across the UV-visual spectrum which is controversial. Any polymer or macro-structure of melanin monomers is 'melanin'. Its roles derive from complex structural and physical-chemical properties e.g. semiconductor, stable radical, conductor, free radical scavenger, charge-transfer. Clinicians and researchers are well acquainted with melanin in skin and ocular pathologies and now increasingly are with internal, melanized, pathology-associated sites not obviously subject to light radiation (e.g. brain, cochlea). At both types of sites some findings puzzle: positive and negative neuromelanin effects in Parkinsons; unexpected melanocyte action in the cochlea, in deafness; melanin reduces DNA damage, but can promote melanoma; in melanotic cells, mitochondrial number was 83% less, respiration down 30%, but development similar to normal amelanotic cells. A little known, avian anatomical conundrum may help resolve melanin paradoxes. One of many unique adaptations to flight, the pecten, strange intra-ocular organ with unresolved function(s), is much enlarged and heavily melanized in birds fighting gravity, hypoxia, thirst and hunger during long-distance, frequently sub-zero, non-stop migration. The pecten may help cope with energy and nutrient needs under extreme conditions, by a marginal but critical, melanin-initiated conversion of light to metabolic energy, coupled to local metabolite recycling. Similarly in Central Africa, reduction in body hair and melanin increase may also have lead to 'photomelanometabolism' which, though small scale/ unit body area, in total may have enabled a sharply increased development of the energy-hungry cortex and enhanced human survival generally. Animal inability to utilize light energy directly has been traditionally assumed. Melanin and the pecten may have unexpected lessons also for human physiology

  16. In vivo isolation of the effects of melanin from underlying hemodynamics across skin types using spatial frequency domain spectroscopy

    Science.gov (United States)

    Saager, Rolf B.; Sharif, Ata; Kelly, Kristen M.; Durkin, Anthony J.

    2016-05-01

    Skin is a highly structured tissue, raising concerns as to whether skin pigmentation due to epidermal melanin may confound accurate measurements of underlying hemodynamics. Using both venous and arterial cuff occlusions as a means of inducing differential hemodynamic perturbations, we present analyses of spectra limited to the visible or near-infrared regime, in addition to a layered model approach. The influence of melanin, spanning Fitzpatrick skin types I to V, on underlying estimations of hemodynamics in skin as interpreted by these spectral regions are assessed. The layered model provides minimal cross-talk between melanin and hemodynamics and enables removal of problematic correlations between measured tissue oxygenation estimates and skin phototype.

  17. 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.

  18. Morpho-histology of head kidney of female catfish Heteropneustes fossilis: seasonal variations in melano-macrophage centers, melanin contents and effects of lipopolysaccharide and dexamethasone on melanins.

    Science.gov (United States)

    Kumar, Ravi; Joy, K P; Singh, S M

    2016-10-01

    In the catfish Heteropneustes fossilis, the anterior kidney is a hemopoietic tissue which surrounds the adrenal homologues, interrenal (IR) and chromaffin tissues corresponding to the adrenal cortical and adrenal medulla of higher mammals. The IR tissue is arranged in cell cords around the posterior cardinal vein (PCV) and its tributaries and secretes corticosteroids. The chromaffin tissue is scattered singly or in nests of one or more cells around the epithelial lining of the PCV or blood capillaries within the IR tissue. They are ferric ferricyanide-positive. Leukemia-inhibitory factor (LIF)-like reactivity was noticed in the lining of the epithelium of the IR cell cords and around the wall of the PCV and blood capillaries. No staining was observed in the hemopoietic cells. IL-1β- and TNF-α-like immunoreactivity was seen in certain cells in the hemopoietic tissue but not in the IR region. Macrophages were identified with mammalian macrophage-specific MAC387 antibodies and are present in the hemopoietic mass but not in the IR tissue. Pigments accumulate in the hemopoietic mass as melano-macrophage centers (MMCs) and are PAS-, Schmorl's- and Perls'-positive. The pigments contain melanin (black), hemosiderin (blue) and lipofuscin/ceroid (oxidized lipid, yellowish tan), as evident from the Perls' reaction. The MMCs were TUNEL-positive as evident from FITC fluorescence, indicating their apoptotic nature. The MMCs showed significant seasonal variation with their density increasing to the peak in the postspawning phase. Melanins were characterized spectrophotometrically for the first time in fish anterior kidney. The predominant form is pheomelanin (PM), followed by eumelanin (EM) and alkali-soluble melanin (ASM). Melanins showed significant seasonal variations with the level low in the resting phase and increasing to the peak in the postspawning phase. Under in vitro conditions, lipopolysaccharide (10 µg/mL) treatment increased significantly the levels of PM and EM

  19. A thioredoxin of Sinorhizobium meliloti CE52G is required for melanin production and symbiotic nitrogen fixation.

    Science.gov (United States)

    Castro-Sowinski, Susana; Matan, Ofra; Bonafede, Paula; Okon, Yaacov

    2007-08-01

    A miniTn5-induced mutant of a melanin-producing strain of Sinorhizobium meliloti (CE52G) that does not produce melanin was mapped to a gene identified as a probable thioredoxin gene. It was proved that the thiol-reducing activity of the mutant was affected. Addition to the growth medium of substrates that induce the production of melanin (L-tyrosine, guaiacol, orcinol) increased the thioredoxin-like (trxL) mRNA level in the wild-type strain. The mutant strain was affected in the response to paraquat-induced oxidative stress, symbiotic nitrogen fixation, and both laccase and tyrosinase activities. The importance of thioredoxin in melanin production in bacteria, through the regulation of laccase or tyrosinase activities, or both, by the redox state of structural or catalytic SH groups, is discussed.

  20. Compositional changes of human hair melanin resulting from bleach treatment investigated by nanoscale secondary ion mass spectrometry.

    Science.gov (United States)

    Kojima, Toru; Yamada, Hiromi; Isobe, Mitsuru; Yamamoto, Toshihiko; Takeuchi, Miyuki; Aoki, Dan; Matsushita, Yasuyuki; Fukushima, Kazuhiko

    2014-11-01

    It is important to understand the influence of bleach treatment on human hair because it is one of the most important chemical treatments in hair cosmetic processes. A comparison of the elemental composition of melanin between virgin hair and bleached hair would provide important information about the structural changes of melanin. To investigate the elemental composition of melanin granules in virgin black hair and bleached hair, these hair cross-sections are analyzed by using a nanoscale secondary ion mass spectrometry (NanoSIMS). The virgin black hair and bleached hair samples were embedded in resin and smooth hair cross-sections were obtained using an ultramicrotome. NanoSIMS measurements were performed using a Cs(+) primary ion beam to detect negative secondary ions. More intensive (16) O(-) ions were detected from the melanin granules of bleached hair than from those of virgin black hair in NanoSIMS (16) O(-) ion image. In addition, it was indicated that (16) O(-) ion intensity and (16) O(-) /(12) C(14) N(-) ion intensity ratio of melanin granules in bleached hair were higher than those in virgin black hair. Nanoscale secondary ion mass spectrometry analysis of the cross-sections of virgin black hair and bleached hair indicated that the oxygen content in melanin granules was increased by bleach treatment. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. [THE INFLUENCE OF MELANIN ON THE GASTRIC MUCOSA AND HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL AXIS UNDER ACUTE STRESS CONDITIONS].

    Science.gov (United States)

    Golyshkin, D V; Falalyeyeva, T M; Neporada, K S; Beregova, T V

    2015-01-01

    We studied the influence of melanin from yeast-like fungi Nadsoniella nigra strain X1 on the changes of the levels of adrenocorticotropic hormone (ACTH) and cortisol in blood serum of rats, adrenal glands weight ratio and lesions of the gastric mucosa (GM) caused by neuromuscular tension by Selye. Melanin administration restored functioning of the hypothalamic-pituitary-adrenal axis that was evident by an increase of ACTH concentration by 42% and a decrease of cortisol concentration by 19% compared to the rats injected with water (group 2). In rats treated with melanin, the adrenal glands weight ratio, didn't differ from intact control group of the rats. Melanin decreased ulcers area by 64% and reduced the content of free hydroxyproline by 29%, the free fucose by 16% and the free hexuronic acids by 24% in the GM compared to the group 2 of the rats. It is established that the mechanism of melanin stress-protective properties are based on its regulation of the glucocorticoids secretion and prevention of GM collagen and extracellular matrix substances depolymerization. Melanin possesses gastroprotective properties and is a perspective agent for preventing and treatment of consequences of the stress influence on the organism.

  2. 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.

  3. 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.

  4. [The magnetic susceptibility of the melanin in the eyes of representatives of different vertebrate classes].

    Science.gov (United States)

    Zagal'skaia, E O

    1995-01-01

    The magnetoperceptivity (Chi) and element composition of eye pigment epitelium (EPE) melanin in vertebrate animals were measured. The minimal values of EPE Chi were found in winter-sleeping and anabiotic animals (Ursus arctos, Rana temporaria). The magnetoperception was high in migrating animals (Oncorhynchus keta, 0. gorbuscha, Anas crecca) and in wild gray rats as well, EPE magnetoperceptivity in albino rats wasn't practicaly established. In the majority of cases the quantity of magnetoperceptivity correlates with per-cent content of iron. The evident correlation between melanin magnet properties and the life strategy of the investigated animals allows to propose the participance of eye pigment epithelium in orientation and navigation of the animals.

  5. 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.

  6. Photochemistry. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure.

    Science.gov (United States)

    Premi, Sanjay; Wallisch, Silvia; Mano, Camila M; Weiner, Adam B; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J H; Halaban, Ruth; Douki, Thierry; Brash, Douglas E

    2015-02-20

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPDs), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. We found that in melanocytes, CPDs are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These "dark CPDs" constitute the majority of CPDs and include the cytosine-containing CPDs that initiate UV-signature C→T mutations. Dark CPDs arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but induces CPDs by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically generated excited electronic states are relevant to mammalian biology.

  7. 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.

  8. Rapid and accurate estimation of blood saturation, melanin content, and epidermis thickness from spectral diffuse reflectance.

    OpenAIRE

    2010-01-01

    We present a method to determine chromophore concentrations, blood saturation, and epidermal thickness of human skin from diffuse reflectance spectra. Human skin was approximated as a plane-parallel slab of variable thickness supported by a semi-infinite layer corresponding to the epidermis and dermis, respectively. The absorption coefficient was modeled as a function of melanin content for the epidermis and blood content and oxygen saturation for the dermis. The scattering coefficient and re...

  9. Skin melanin degradation%皮肤黑素降解的研究进展

    Institute of Scientific and Technical Information of China (English)

    周颖丽; 宋秀祖

    2014-01-01

    The difference in human skin complexion is mainly determined by melanin content,type and distribution (granular or scattered).It is considered that melanin is synthesized in melanocytes firstly,then transported from melanocytes to keratinocytes through a variety of ways,degraded in keratinocytes,and finally passes out of the body.Although there have been many studies on the production and transport of melanin,little is known about the degradation process of melanin in keratinocytes.Autophagy is likely to play an important role in this process.%人类皮肤颜色的差异主要由黑素在皮肤中的含量、种类及其分布状态(颗粒状或分散状)来决定.黑素在黑素细胞的黑素小体内被合成后,借助多种途径完成在黑素细胞内以及从黑素细胞到邻近角质形成细胞的转运,最终在角质形成细胞内被降解而排出体外.对于黑素的生成和转运,各方面的研究很多,而对黑素在角质形成细胞内的降解过程研究甚少,机制尚不明了.目前研究认为,自噬在其中发挥着重要的作用.

  10. 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.

  11. 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.

  12. Toxicological and melanin synthesis effects of Polygonum multiflorum root extracts on zebrafish embryos and human melanocytes

    Directory of Open Access Journals (Sweden)

    Thanh Thi Hoai Dang

    2016-09-01

    Full Text Available Polygonum multiflorum (PM has been commmonly used as folk medicine for treatment of various conditions, such as early graying of hair in humans. However, there have been limited studies which have evaluated the toxicological and biological effects of PM in vitro as well as in vivo. In this study, PM root extracts in ethyl acetate (PM-E and in distilled water (PM-W were examined for their effects on the development of teratogenic defects/deaths. Additionally, they were evaluated for their effects on melanin formation in human melanocytes and pigmentation in embryos/larvae of wild type strain AB zebrafish (Danio rerio. Our results showed that PM root extracts at concentrations of 40 mg/L and 105 mg/L induced the development of teratogenic defects, including yolk sac edema (or heart edema, hemovascular defects, necrosis and abnormal trunk in zebrafish embryos at 4 days post fertilization; teratogenic indexes (TIs were 1.43 and 0.63 for ethyl acetate extract and distilled water extract, respectively. Our results also demonstrated that PM-W significantly increased the pigmentation level of embryos/larvae and induced melanin formation in human melanocytes. The amount of melanin in PM-W-exposed embryos/larvae was 2.2-fold and 1.71-fold greater than those in the control embryos/larvae and control melanocytes, respectively. Our study also showed that the increased level of pigmentation in PM-W embryos/larvae or melanin biosynthesis in melanocytes were both regulated by activation of tyrosinase. Conclusively, our study suggests that PM root extracts could be used as potential agents for treatment of early hair graying as well as various other diseases related to loss of pigmentation. However, these PM root extracts may also have some negative effects on embryos; therefore it should be careful when using for women during pregnancy. [Biomed Res Ther 2016; 3(9.000: 808-818

  13. The Protective Role of Melanin Against UV Damage in Human Skin

    OpenAIRE

    Brenner, Michaela; Hearing, Vincent J.

    2008-01-01

    Human skin is repeatedly exposed to ultraviolet radiation (UVR) that influences the function and survival of many cell types and is regarded as the main causative factor in the induction of skin cancer. It has been traditionally believed that skin pigmentation is the most important photoprotective factor, since melanin, besides functioning as a broadband UV absorbent, has antioxidant and radical scavenging properties. Besides, many epidemiological studies have shown a lower incidence for skin...

  14. Endothelin-1 increases melanin synthesis in an established sheep skin melanocyte culture.

    Science.gov (United States)

    Pang, Yamiao; Geng, Jianjun; Qin, Yilong; Wang, Haidong; Fan, Ruiwen; Zhang, Ying; Li, Hongquan; Jiang, Shan; Dong, Changsheng

    2016-08-01

    The aims of the study were to establish a culture system for sheep skin melanocytes and uncover the effects of endothelin-1 on melanin synthesis in cultured melanocytes in order to provide an optimal cell system and a theoretical basis for studying the regulatory mechanism of coat color in sheep. In this study, skin punch biopsies were harvested from the dorsal region of 1-3-yr-old sheep, and skin melanocytes were then obtained by the two-step digestion using dispase II and trypsin/ethylene diamine tetraacetic acid (EDTA). The primary cultures of the melanocytes were established and characterized by dopa-staining, immunocytochemical localization of melanocyte markers, and RT-polymerase chain reaction (PCR) analysis of coat color genes. To determine the effect of endothelin-1 on proliferation and melanin synthesis of melanocytes, the cultured cells were treated with different doses of endothelin-1 (10(-7), 10(-8), 10(-9), 10(-10), and 0 mol/L), and the growth rate of melanocytes, production of melanin, expression of related genes, and location of related protein in cultured cells were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), ultraviolet spectrophotometry, qRT-PCR, and immunocytochemical localization, respectively. The results showed that the established melanocyte culture functions properly. Endothelin-1 treatment increased markedly the number of melanocytes and melanin content. In responding to this treatment, expressions of microphthalmia-associated transcription factor (MITF), melanocortin 1 receptor (MC1R), tyrosinase (TYR), and endothelin receptor B (EDNRB) in the melanocytes were significantly up regulated (P skin melanocytes was established successfully in vitro, and endothelin-1 promotes the melanogenesis in sheep skin melanocytes.

  15. Arbutin encapsulated micelles improved transdermal delivery and suppression of cellular melanin production

    OpenAIRE

    Liang, Ke; Xu, Keming; Bessarab, Dmitri; Obaje, Jonathan; Xu, Chenjie

    2016-01-01

    Background Hyperpigmentation is a skin disorder characterized by elevated production of melanin. Current treatment approaches mainly rely on the application of skin lightening chemicals, most of which have safety issues. Efficacy of delivery of the active ingredients to the target organ has also been a challenge. Transdermal based drug delivery platform has been shown to improve drug bioavailability, avoiding the hepatic first pass metabolism, decrease gastrointestinal side effects, and event...

  16. 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. PMID

  17. Biocatalysis on the surface of Escherichia coli: melanin pigmentation of the cell exterior

    Science.gov (United States)

    Gustavsson, Martin; Hörnström, David; Lundh, Susanna; Belotserkovsky, Jaroslav; Larsson, Gen

    2016-01-01

    Today, it is considered state-of-the-art to engineer living organisms for various biotechnology applications. Even though this has led to numerous scientific breakthroughs, the enclosed interior of bacterial cells still restricts interactions with enzymes, pathways and products due to the mass-transfer barrier formed by the cell envelope. To promote accessibility, we propose engineering of biocatalytic reactions and subsequent product deposition directly on the bacterial surface. As a proof-of-concept, we used the AIDA autotransporter vehicle for Escherichia coli surface expression of tyrosinase and fully oxidized externally added tyrosine to the biopolymer melanin. This resulted in a color change and creation of a black cell exterior. The capture of ninety percent of a pharmaceutical wastewater pollutant followed by regeneration of the cell bound melanin matrix through a simple pH change, shows the superior function and facilitated processing provided by the surface methodology. The broad adsorption spectrum of melanin could also allow removal of other micropollutants. PMID:27782179

  18. 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.

  19. 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.

  20. Prenylated flavonoids from Artocarpus altilis: antioxidant activities and inhibitory effects on melanin production.

    Science.gov (United States)

    Lan, Wen-Chun; Tzeng, Cheng-Wei; Lin, Chun-Ching; Yen, Feng-Lin; Ko, Horng-Huey

    2013-05-01

    Flavonoids, 10-oxoartogomezianone (1), 8-geranyl-3-(hydroxyprenyl)isoetin (2), hydroxyartoflavone A (3), isocycloartobiloxanthone (4), and furanocyclocommunin (5), together with 12 known compounds, were isolated from heartwood and cortex of Artocarpus altilis, and their structures were identified by comparing their spectra with those of similar compounds. To identify natural antioxidants and whitening agents, the ability of these prenylated flavonoids was assessed to scavenge the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+·)) radical cation, and the superoxide anion (O2(-·)), and their abilities to inhibit tyrosinase and melanin production. It was found that compounds 3, 4, and artoflavone A (15) had moderate DPPH(·)-scavenging activity, whereas compound 4 exhibited significant ABTS(+·)-scavenging activity, and that norartocarpetin (7) and artogomezianone (8) exhibited moderate ABTS(+·)-scavenging activity, with compounds 2, 7, and artocarpin (6) displaying good superoxide anion-scavenging activity. In addition, compounds 7, 8, cudraflavone A (14), and artonin M (17), inhibited melanin production by strongly suppressing tyrosinase activity. Compound 6 reduced the melanin content without inhibiting tyrosinase activity. These results suggest that flavonoids isolated from A. altilis may be candidate antioxidants and/or skin-whitening agents. However, further investigations are required to determine their mechanisms of action. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Studies on Synthetic and Natural Melanin and Its Affinity for Fe(III Ion

    Directory of Open Access Journals (Sweden)

    T. G. Costa

    2012-01-01

    Full Text Available In this work, we measured the metal-binding sites of natural and synthetic dihydroxyindole (DHI melanins and their respective interactions with Fe(III ions. Besides the two acid groups detected for the DHI system: catechol (Cat and quinone-imine (QI, acetate groups were detected in the natural oligomer by potentiometric titrations. At acidic pH values, Fe(III complexation with synthetic melanin was detected in an Fe(OH(CatH2Cat interaction. With an increase of pH, three new interactions occurred: dihydroxide diprotonated catechol, Fe(OH2(CatH2Cat−, dihydroxide monoprotonated catechol, [Fe(OH2(CatHCat]2−, and an interaction resulting from the association of one quinone-imine and a catechol group, [Fe(OH2(Qi−(CatHCat]3−. In the natural melanin system, we detected the same interactions involving catechol and quinone-imine groups but also the metal interacts with acetate group at pH values lower than 4.0. Furthermore, interactions in the synthetic system were also characterized by infrared spectroscopy by using the characteristic vibrations of catechol and quinone-imine groups. Finally, scanning electronic microscopy (SEM and energy-dispersive X-ray (EDS analysis were used to examine the differences in morphology of these two systems in the absence and presence of Fe(III ions. The mole ratio of metal and donor atoms was obtained by the EDS analysis.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 黑素及其对真菌毒力的影响%Melanin and its contribution to fungal virulence

    Institute of Scientific and Technical Information of China (English)

    张晓利; 吕雪莲; 刘维达

    2008-01-01

    Melanin is a kind of dark-brown or black negative charged materials formed by the oxidative polymerization of phenolic compounds. Melanin synthesis is associated with the virulence of a number of human pathogenic fungi. Melanin can enhance the pathogenicity and survival of infective fungi by protecting them against environmental damage, oxidative injury and antifungal agents. It has been observed that the melanin in Cryptococcus neoformans, Fonsecaea pedrosoi and Sporotrichum schenckii is closely related to the virulence of these fungi. This article presents the possible mechanisms underlying the enhancement of fungal virulence by melanin.%黑素是一类带负电荷的暗褐色或黑色物质,多由酚类化合物氧化聚合而成.黑素的合成与多种人类致病性真菌的毒力相关,它具有保护真菌免受环境因素损伤、抗氧化、抗宿主防御系统和耐受抗真菌药物等作用,从而能够提高菌株在宿主内的存活率,增强对宿主的致病能力.新生隐球菌,裴氏着色芽生菌及申克孢子丝菌等存在的黑素与毒力密切相关,探讨黑素能增强真菌毒力的机制.

  7. The pbrB gene encodes a laccase required for DHN-melanin synthesis in conidia of Talaromyces (Penicillium) marneffei.

    Science.gov (United States)

    Sapmak, Ariya; Boyce, Kylie J; Andrianopoulos, Alex; Vanittanakom, Nongnuch

    2015-01-01

    Talaromyces marneffei (Basionym: Penicillium marneffei) is a significant opportunistic fungal pathogen in patients infected with human immunodeficiency virus in Southeast Asia. T. marneffei cells have been shown to become melanized in vivo. Melanins are pigment biopolymers which act as a non-specific protectant against various stressors and which play an important role during virulence in fungi. The synthesis of the two most commonly found melanins in fungi, the eumelanin DOPA-melanin and the allomelanin DHN-melanin, requires the action of laccase enzymes. The T. marneffei genome encodes a number of laccases and this study describes the characterization of one of these, pbrB, during growth and development. A strain carrying a PbrB-GFP fusion shows that pbrB is expressed at high levels during asexual development (conidiation) but not in cells growing vegetatively. The pbrB gene is required for the synthesis of DHN-melanin in conidia and when deleted results in brown pigmented conidia, in contrast to the green conidia of the wild type.

  8. 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.

  9. 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

  10. Dopamine-melanin film deposition depends on the used oxidant and buffer solution.

    Science.gov (United States)

    Bernsmann, Falk; Ball, Vincent; Addiego, Frédéric; Ponche, Arnaud; Michel, Marc; Gracio, José Joaquin de Almeida; Toniazzo, Valérie; Ruch, David

    2011-03-15

    The deposition of "polydopamine" films, from an aqueous solution containing dopamine or other catecholamines, constitutes a new and versatile way to functionalize solid-liquid interfaces. Indeed such films can be deposited on almost all kinds of materials. Their deposition kinetics does not depend markedly on the surface chemistry of the substrate, and the films can reach thickness of a few tens of nanometers in a single reaction step. Up to now, even if a lot is known about the oxidation mechanism of dopamine in solution, only little information is available to describe the deposition mechanism on surfaces either by oxidation in solution or by electrodeposition. The deposition kinetics of melanin was only investigated from dopamine solutions using oxygen or ammonium persulfate as an oxidant and from a tris(hydroxymethyl) aminomethane (Tris) containing buffer solutions at pH 8.5. Many other oxidants could be used, and the buffer agent containing a primary amine group may influence the deposition process. Herein we show that the deposition kinetics of melanin from dopamine containing buffers at pH 8.5 can be markedly modified using Cu(2+) instead of O2 as an oxidant: the deposition kinetics remains linear up to thicknesses of more than 70 nm, whereas the film growth stops at 45 ± 5 nm in the presence of 02. In addition, the films prepared from Cu(2+) containing solutions display an absorption spectrum with defined peaks at 320 and 370 nm, which are absent in the spectra of films prepared in oxygenated solutions. The replacement of Tris buffer by phosphate buffer also has a marked effect on the melanin deposition kinetics.

  11. 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.

  12. 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

  13. New insights into the physicochemical effects of ammonia/peroxide bleaching of hair and Sepia melanins.

    Science.gov (United States)

    Prem, Padmaja; Dube, Katherine J; Madison, Stephen A; Bartolone, John

    2003-01-01

    Chemically unaltered melanosomes from black hair were isolated using a mild enzymatic procedure reported by Novellino et al. involving sequential treatment of a homogenized hair sample with different protease enzymes. Time-dependent fluorescence studies show, under identical conditions, that the rate of bleaching upon NH3/H2O2 treatment of hair melanosomes is twice that of Sepia melanosomes. The structure and morphology of hair melanosomes are compared to Sepia eumelanin using ESEM and TEM imaging studies. Black hair melanosomes are aggregates of rice-shaped ellipsoidal particles (0.8-1.0 microm in length and 0.2-0.6 microm in width) surrounded by an amorphous material suspected to be made of non-proteinacious materials. Sepia eumelanin aggregates are larger (2-5 microm) particles with a "doughnut" shape comprised of 100-150-nm spherical particles. Time-dependent TEM imaging studies of ammonia-treated (pH 10) hair melanosomes showed an initial breakdown of melanosomal aggregates followed by rupture of the melanosomal membrane, releasing melanin nanoparticles and leaving a ghost membrane behind. After prolonged treatment with aqueous NH3, a total loss of characteristic melanosome morphology was observed leading to an amorphous material. By contrast, Sepia melanosomes under identical conditions of ammonia treatment did not show such changes, probably due to different surface properties and aggregation behavior. Sodium hydroxide or sodium carbonate at identical pH did not show similar changes to ammonia, suggesting that the changes are not merely due to alkaline pH, but, rather, are specific to ammonia. Co-treatment with ammonia and peroxide induced a faster disintegration of the melanosomes, resulting in a complete dissolution and discoloration of melanin in 30 minutes. The data suggest that ammonia helps to release melanin nanoparticles out of melanosomes, making them more susceptible to oxidative attack by H2O2.

  14. 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.

  15. Duration of reappearance of gingival melanin pigmentation after surgical removal — A clinical study

    Science.gov (United States)

    Kaur, Harjit; Jain, Sanjeev; Sharma, Roshan Lal

    2010-01-01

    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. PMID:21691546

  16. Comparison of the effectiveness between 2% and 4% nicotinamide gel in reducing melanin index

    OpenAIRE

    Lisa Murtisari, Lisa Murtisari

    2015-01-01

    Background: Nicotinamide is a safe agent inhibiting melanosome transfer in vitro therefore it can reduce skin pigmentation. Two percent nicotinamide cream combined with sunscreen as a lightening agent in-creases skin lightness in vivo. Measurement of skin colour changes can be performed by mexameter to measure melanin index (MI).Objective: This study was aimed to compare the effectiveness of 2% and 4% nicotinamide gel as a lightening agent in reducing MI.Materials and Methods: This study was ...

  17. Comparison of the effectiveness between 2% and 4% nicotinamide gel in reducing melanin index

    OpenAIRE

    Lisa Murtisari, Lisa Murtisari

    2015-01-01

    Background: Nicotinamide is a safe agent inhibiting melanosome transfer in vitro therefore it can reduce skin pigmentation. Two percent nicotinamide cream combined with sunscreen as a lightening agent in-creases skin lightness in vivo. Measurement of skin colour changes can be performed by mexameter to measure melanin index (MI).Objective: This study was aimed to compare the effectiveness of 2% and 4% nicotinamide gel as a lightening agent in reducing MI.Materials and Methods: This study was ...

  18. Melanin synthesis is associated with changes in hyphopodial turgor, permeability, and wall rigidity in gaeumannomyces graminis var. graminis.

    Science.gov (United States)

    Money, N P; Caesar-TonThat, T C; Frederick, B; Henson, J M

    1998-01-01

    Mycelia of Gaeumannomyces graminis var. graminis form large cells called hyphopodia with deeply lobed, melanized walls. Like appressoria produced by other pathogens, hyphopodia develop on hydrophobic surfaces, but it is not clear that hyphopodia function as platforms for host penetration. In appressoria, melanin synthesis is linked to the generation of enormous turgor pressures that provide the necessary force for plant penetration. In the present study, hyphopodial turgor was measured in a wild-type strain of G. graminis var. graminis, a mutant exhibiting constitutive synthesis of melanin (referred to as the dark mutant), and a melanin-deficient strain (thr). These experiments demonstrate that hyphopodia of the wild-type strain generate higher pressures than the dark mutant and that nonmelanized thr hyphopodia generate minuscule internal pressures. Melanization of the wall is also associated with an increase in its rigidity. These data correlate with differences in wall permeability consistent with a recent model for turgor generation by appressoria.

  19. Melanin and blood concentration in a human skin model studied by multiple regression analysis: assessment by Monte Carlo simulation

    Science.gov (United States)

    Shimada, M.; Yamada, Y.; Itoh, M.; Yatagai, T.

    2001-09-01

    Measurement of melanin and blood concentration in human skin is needed in the medical and the cosmetic fields because human skin colour is mainly determined by the colours of melanin and blood. It is difficult to measure these concentrations in human skin because skin has a multi-layered structure and scatters light strongly throughout the visible spectrum. The Monte Carlo simulation currently used for the analysis of skin colour requires long calculation times and knowledge of the specific optical properties of each skin layer. A regression analysis based on the modified Beer-Lambert law is presented as a method of measuring melanin and blood concentration in human skin in a shorter period of time and with fewer calculations. The accuracy of this method is assessed using Monte Carlo simulations.

  20. Using Sepia melanin as a PD model to describe the binding characteristics of neuromelanin - A critical review.

    Science.gov (United States)

    Schroeder, Rhiannon L; Double, Kay L; Gerber, Jacobus P

    2015-01-01

    Parkinson's disease is characterised pathologically by a relatively selective death of dopaminergic neurons in the substantia nigra of the brain. The vulnerability of these neurons appears to be linked to the pigment neuromelanin. However, as yet there is limited understanding behind the mechanisms of this disease process. Complications arise due to the difficulty in obtaining appreciable quantities of neuromelanin. Furthermore, an appropriate model for studying neuromelanin has not been identified. To date there has been many studies looking at the binding and chemical characteristics of neuromelanin. However, a range of different synthetic and organic melanins have been used as models and leading to many varied conclusions being drawn. Therefore, the aim of this review is to present Sepia melanin as the most appropriate study model for the binding characteristics of neuromelanin. Considerations included chemical structure, surface characteristics and structural features of both synthetic and organic melanins.

  1. 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.

  2. High-Throughput Melanin-Binding Affinity and In Silico Methods to Aid in the Prediction of Drug Exposure in Ocular Tissue.

    Science.gov (United States)

    Reilly, John; Williams, Sarah L; Forster, Cornelia J; Kansara, Viral; End, Peter; Serrano-Wu, Michael H

    2015-12-01

    Drugs possessing the ability to bind to melanin-rich tissue, such as the eye, are linked with higher ocular exposure, and therefore have the potential to affect the efficacy and safety profiles of therapeutics. A high-throughput melanin chromatographic affinity assay has been developed and validated, which has allowed the rapid melanin affinity assessment for a large number of compounds. Melanin affinity of compounds can be quickly assigned as low, medium, or high melanin binders. A high-throughput chromatographic method has been developed and fully validated to assess melanin affinity of pharmaceuticals and has been useful in predicting ocular tissue distribution in vivo studies. The high-throughput experimental approach has also allowed for a specific training set of 263 molecules for a quantitative structure-affinity relationships (QSAR) method to be developed, which has also been shown to be a predictor of ocular tissue exposure. Previous studies have reported the development of in silico QSAR models based on training sets of relatively small and mostly similar compounds; this model covers a broader range of melanin-binding affinities than what has been previously published and identified several physiochemical descriptors to be considered in the design of compounds where melanin-binding modulation is desired.

  3. Protein adsorption on dopamine-melanin films: role of electrostatic interactions inferred from zeta-potential measurements versus chemisorption.

    Science.gov (United States)

    Bernsmann, Falk; Frisch, Benoît; Ringwald, Christian; Ball, Vincent

    2010-04-01

    We recently showed the possibility to build dopamine-melanin films of controlled thickness by successive immersions of a substrate in alkaline solutions of dopamine [F. Bernsmann, A. Ponche, C. Ringwald, J. Hemmerlé, J. Raya, B. Bechinger, J.-C. Voegel, P. Schaaf, V. Ball, J. Phys. Chem. C 113 (2009) 8234-8242]. In this work the structure and properties of such films are further explored. The zeta-potential of dopamine-melanin films is measured as a function of the total immersion time to build the film. It appears that the film bears a constant zeta-potential of (-39+/-3) mV after 12 immersion steps. These data are used to calculate the surface density of charged groups of the dopamine-melanin films at pH 8.5 that are mostly catechol or quinone imine chemical groups. Furthermore the zeta-potential is used to explain the adsorption of three model proteins (lysozyme, myoglobin, alpha-lactalbumin), which is monitored by quartz crystal microbalance. We come to the conclusion that protein adsorption on dopamine-melanin is not only determined by possible covalent binding between amino groups of the proteins and catechol groups of dopamine-melanin but that electrostatic interactions contribute to protein binding. Part of the adsorbed proteins can be desorbed by sodium dodecylsulfate solutions at the critical micellar concentration. The fraction of weakly bound proteins decreases with their isoelectric point. Additionally the number of available sites for covalent binding of amino groups on melanin grains is quantified.

  4. Topical liposome targeting of dyes, melanins, genes, and proteins selectively to hair follicles.

    Science.gov (United States)

    Hoffman, R M

    1998-01-01

    For therapeutic and cosmetic modification of hair, we have developed a hair-follicle-selective macromolecule and small molecule targeting system with topical application of phosphatidylcholine-based liposomes. Liposome-entrapped melanins, proteins, genes, and small-molecules have been selectively targeted to the hair follicle and hair shafts of mice. Liposomal delivery of these molecules is time dependent. Negligible amounts of delivered molecules enter the dermis, epidermis, or bloodstream thereby demonstrating selective follicle delivery. Naked molecules are trapped in the stratum corneum and are unable to enter the follicle. The potential of the hair-follicle liposome delivery system for therapeutic use for hair disease as well as for cosmesis has been demonstrated in 3-dimensional histoculture of hair-growing skin and mouse in vivo models. Topical liposome selective delivery to hair follicles has demonstrated the ability to color hair with melanin, the delivery of the active lac-Z gene to hair matrix cells and delivery of proteins as well. Liposome-targeting of molecules to hair follicles has also been achieved in human scalp in histoculture. Liposomes thus have high potential in selective hair follicle targeting of large and small molecules, including genes, opening the field of gene therapy and other molecular therapy of the hair process to restore hair growth, physiologically restore or alter hair pigment, and to prevent or accelerate hair loss.

  5. Olanzapine-induced changes in glucose metabolism are independent of the melanin-concentrating hormone system.

    Science.gov (United States)

    Girault, Elodie M; Toonen, Pim W; Eggels, Leslie; Foppen, Ewout; Ackermans, Mariëtte T; la Fleur, Susanne E; Fliers, Eric; Kalsbeek, Andries

    2013-11-01

    Atypical antipsychotic drugs such as Olanzapine (Ola) induce weight gain and metabolic changes associated with the development of type 2 diabetes. The mechanisms underlying these undesired side-effects are currently unknown. Chagnon et al. showed that the common allele rs7973796 of the prepro-melanin-concentrating hormone (PMCH) gene is associated with a greater body mass index in Ola-treated schizophrenic patients. As PMCH encodes for the orexigenic neuropeptide melanin-concentrating hormone (MCH), it was hypothesized that MCH is involved in Ola-induced metabolic changes. We have recently reported that the intragastric infusion of Ola results in hyperglycaemia and insulin resistance in male rats. In order to test in vivo the possible involvement of the PMCH gene in the pathogenesis of Ola side-effects, we administered Ola intragastrically in wild-type (WT) and PMCH knock-out (KO) rats. Our results show that glucose and corticosterone levels, as well as endogenous glucose production, are elevated by the infusion of Ola in both WT and KO animals. Thus, the lack of MCH does not seem to affect the acute effects of Ola on glucose metabolism. On the other hand, these effects might be obliterated by compensatory changes in other hypothalamic systems. In addition, possible modulatory effects of the MCH KO on the long term effects of Ola, i.e. increased adiposity, body weight gain, have not been investigated yet.

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

    Science.gov (United States)

    Serrano, Gabriel; Almudéver, Patricia; Serrano, Juan M; Cortijo, Julio; Faus, Carmen; Reyes, Magda; Expósito, Inmaculada; Torrens, Ana; Millán, Fernando

    2015-01-01

    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. PMID:26170707

  7. Action of 2,2',4,4'-tetrahydroxybenzophenone in the biosynthesis pathway of melanin.

    Science.gov (United States)

    Garcia-Jimenez, Antonio; Teruel-Puche, Jose Antonio; Garcia-Ruiz, Pedro Antonio; Berna, Jose; Rodríguez-López, Jose Neptuno; Tudela, Jose; Garcia-Canovas, Francisco

    2017-05-01

    2,2',4,4'-tetrahydroxybenzophenone (Uvinul D50), a sunscreen used in cosmetics, has two effects in the melanin biosynthesis pathway. On the one hand, it acts a weak inhibitor of tyrosinase and on the other, it accelerates the conversion of dopachrome to melanin. Uvinul D50 was seen to behave as a weak competitive inhibitor: apparent constant inhibition=2.02±0.09mM and IC50=3.82±0.39mM established in this work. These values are higher than those in the bibliography, which tend to be undersetimated. This discrepancy could be explained by the reaction of Uvinul D50 with the dopachrome produced from l-tyrosine or l-dopa, which would interfere in the measurement. Based on studies of its docking to tyrosinase, it seems that Uvinul D50 interacts with the active site of the enzyme (oxytyrosinase) both in its protonated and deprotonated forms (pKa=7). However, it cannot be hydroxylated, meaning that it acts as a weak inhibitor, not as an alternative substrate, despite its resorcinol structure. Uvinul D50 can be used as sunscreen, in low concentrations without significant adverse effects on melanogenesis.

  8. 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.

  9. Heavy Water as a Probe of the Free Radical Nature and Electrical Conductivity of Melanin.

    Science.gov (United States)

    Rienecker, Shermiyah B; Mostert, A Bernardus; Schenk, Gerhard; Hanson, Graeme R; Meredith, Paul

    2015-12-01

    Melanins are pigmentary macromolecules found in many locations throughout nature including plants and vertebrate animals. It was recently proposed that the predominant brown-black pigment eumelanin is a mixed ionic-electronic conductor which has led to renewed interest in its basic properties as a model bioelectronic material. This exotic hybrid electrical behavior is strongly dependent upon hydration and is closely related to the free radical content of melanin which is believed to be a mixed population of two species: the semiquinone (SQ) and a carbon-centered radical (CCR). The predominant charge carrier is the proton that is released during the formation of the SQ radical and controlled by a comproportionation equilibrium reaction. In this paper we present a combined solid-state electron paramagnetic resonance (EPR), adsorption, and hydrated conductivity study using D2O as a probe. We make specific predictions as to how the heavy isotope effect, in contrast to H2O, should perturb the comproportionation equilibrium and the related outcome as far as the electrical conductivity is concerned. Our EPR results confirm the proposed two-spin mechanism and clearly demonstrate the power of combining macroscopic measurements with observations from mesoscopic probes for the study of bioelectronic materials.

  10. 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.

  11. 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.

  12. Effect of norfloxacin and moxifloxacin on melanin synthesis and antioxidant enzymes activity in normal human melanocytes.

    Science.gov (United States)

    Beberok, Artur; Wrześniok, Dorota; Otręba, Michał; Miliński, Maciej; Rok, Jakub; Buszman, Ewa

    2015-03-01

    Fluoroquinolone antibiotics provide broad-spectrum coverage for a number of infectious diseases, including respiratory as well as urinary tract infections. One of the important adverse effects of these drugs is phototoxicity which introduces a serious limitation to their use. To gain insight the molecular mechanisms underlying the fluoroquinolones-induced phototoxic side effects, the impact of two fluoroquinolone derivatives with different phototoxic potential, norfloxacin and moxifloxacin, on melanogenesis and antioxidant enzymes activity in normal human melanocytes HEMa-LP was determined. Both drugs induced concentration-dependent loss in melanocytes viability. The value of EC50 for these drugs was found to be 0.5 mM. Norfloxacin and moxifloxacin suppressed melanin biosynthesis; antibiotics were shown to inhibit cellular tyrosinase activity and to reduce melanin content in melanocytes. When comparing the both analyzed fluoroquinolones, it was observed that norfloxacin possesses greater inhibitory effect on tyrosinase activity in melanocytes than moxifloxacin. The extent of oxidative stress in cells was assessed by measuring the activity of antioxidant enzymes: SOD, CAT, and GPx. It was observed that norfloxacin caused higher depletion of antioxidant status in melanocytes when compared with moxifloxacin. The obtained results give a new insight into the mechanisms of fluoroquinolones toxicity directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various phototoxic activities of the analyzed fluoroquinolone derivatives in vivo.

  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. 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.

  15. 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)

  16. Black perithecial pigmentation in Fusarium species is due to the accumulation of 5-deoxybostrycoidin-based melanin

    DEFF Research Database (Denmark)

    Frandsen, Rasmus John Normand; Rasmussen, Silas Anselm; Knudsen, Peter Boldsen

    2016-01-01

    anthrone (4) and purpurfusarin (5). The novel dimeric bostrycoidin purpurfusarin (5) was found to inhibit the growth of Candida albicans with an IC50 of 8.0 +/-1.9 mu M. The results show that Fusarium species with black perithecia have a previously undescribed form of 5-deoxybostrycoidin based melanin...

  17. [Influence of low dozes of ionizing radiation on accumulation of melanin pigments and catalase and superoxidedismutase activities in Cladosporium cladosporioides].

    Science.gov (United States)

    Tuhaĭ, T I

    2007-01-01

    Influence of low dozes of ionizing radiation on melanin pigments synthesis and activity of antioxidant enzymes catalase and superoxidedismutase of two strains of Cladosporium cladosporioides 4, (isolated from radioactive soil) and 396 (control) were investigated. It was shown, that in C. cladosporioides 4 under the exposure of ionizing radiation an increase of melanin synthesis in a stationary growth phase and increase of superoxidedismutase activity in a logarithmic phase were observed; in the control strain C. cladosporioides 396 activation of melanin synthesis and superoxide dismutase activity in both growth phases was revealed. It was established that in C. cladosporioides 4 the endocellular catalase activity in a logarithmic phase is 3.2 times higher, than in control strain. Under the action of ionizing radiation a 2-fold increase of this enzyme activity unlike the control strain in which the activity inhibition was revealed. The obtained results testify to the complex response of antioxidant systems and melanin to the action of low dozes of radiation which depends on the growth phase and presence of radioadaptation properties in the investigated fungi.

  18. Human eccrine sweat gland cells turn into melanin-uptaking keratinocytes in dermo-epidermal skin substitutes.

    Science.gov (United States)

    Böttcher-Haberzeth, Sophie; Biedermann, Thomas; Pontiggia, Luca; Braziulis, Erik; Schiestl, Clemens; Hendriks, Bart; Eichhoff, Ossia M; Widmer, Daniel S; Meuli-Simmen, Claudia; Meuli, Martin; Reichmann, Ernst

    2013-02-01

    Recently, Biedermann et al. (2010) have demonstrated that human eccrine sweat gland cells can develop a multilayered epidermis. The question still remains whether these cells can fulfill exclusive and very specific functional properties of epidermal keratinocytes, such as the incorporation of melanin, a feature absent in sweat gland cells. We added human melanocytes to eccrine sweat gland cells to let them develop into an epidermal analog in vivo. The interaction between melanocytes and sweat gland-derived keratinocytes was investigated. The following results were gained: (1) macroscopically, a pigmentation of the substitutes was seen 2-3 weeks after transplantation; (2) we confirmed the development of a multilayered, stratified epidermis with melanocytes distributed evenly throughout the basal layer; (3) melanocytic dendrites projected to suprabasal layers; and (4) melanin was observed to be integrated into former eccrine sweat gland cells. These skin substitutes were similar or equal to skin substitutes cultured from human epidermal keratinocytes. The only differences observed were a delay in pigmentation and less melanin uptake. These data suggest that eccrine sweat gland cells can form a functional epidermal melanin unit, thereby providing striking evidence that they can assume one of the most characteristic keratinocyte properties.

  19. 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.

  20. 2-Ethoxybenzamide stimulates melanin synthesis in B16F1 melanoma cells via the CREB signaling pathway.

    Science.gov (United States)

    Sato, Kazuomi; Ando, Ryosuke; Kobayashi, Honoka; Nishio, Takashi

    2016-12-01

    Non-steroidal anti-inflammatory drugs are frequently used for the treatment of inflammation, pain, and fever. In this study, we found that 2-ethoxybenzamide (ETZ) significantly enhanced melanin synthesis in B16F1 melanoma cells, and also induced melanosome formation. Therefore, we investigated the mechanism by which ETZ up-regulated melanin synthesis. Western blot analysis demonstrated that ETZ increased melanogenic protein levels, except that for TRP-2. Moreover, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR analyses showed that ETZ enhanced the mRNA levels of melanogenic genes, including microphthalmia-associated transcription factor and melanocortin 1 receptor. We also observed phosphorylation of cAMP response element-binding protein (CREB) following ETZ treatment. However, ETZ did not affect intracellular cAMP levels. ERK was also activated by ETZ treatment, and melanin content was enhanced upon treatment with the specific ERK inhibitor PD98059. Together, our results indicate that ETZ induces melanin synthesis via CREB phosphorylation.

  1. 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.

  2. Melanin index in assessing the treatment efficacy of 1064 nm Q switched Nd-Yag laser in nevus of Ota

    Directory of Open Access Journals (Sweden)

    Gomathy Sethuraman

    2013-01-01

    Full Text Available Background: Q-switched neodymium-yttrium aluminium-garnet (Q switched Nd-Yag laser has been used in the treatment of nevus of Ota in all skin types with variable success rate. Data with an objective assessment parameter to this laser treatment is lacking. Objective: To evaluate the utility of melanin index in assessing the treatment response and also determine the efficacy and safety of the Q-switched Nd-Yag laser (1064-nm in the treatment of nevus of Ota in Fitzpatrick skin types IV and V. Materials and Methods: A total of 35 patients treated with Nd-Yag laser were studied. The objective improvement (pigment clearance was determined by melanin index from two fixed points: A1, 2 cm below the pupil at the mid pupillary line (when the gaze is fixed; A2, the most prominent part of zygoma. The melanin index in these two areas was recorded as M1 and M2, respectively. The subjective clinical improvement was determined by the physician and the patient global assessment score. Results: The mean baseline melanin indices M1 and M2 were 59.54 ± 9.72 and 59.02 ± 9.16, respectively. At the last visit the mean M1 and M2 decreased to 53.8 ± 8.55 (P 50% pigment clearance. Conclusion: The melanin index, a simple non-invasive parameter is useful in assessing the treatment response more objectively. The 1064-nm Q-switched Nd-Yag laser offers good improvement in patients with nevus of Ota in darker skin types IV/V.

  3. Melanin Index in Assessing the Treatment Efficacy of 1064 nm Q Switched Nd-Yag Laser in Nevus of Ota

    Science.gov (United States)

    Sethuraman, Gomathy; Sharma, Vinod K; Sreenivas, Vishnubhatla

    2013-01-01

    Background: Q-switched neodymium-yttrium aluminium-garnet (Q switched Nd-Yag) laser has been used in the treatment of nevus of Ota in all skin types with variable success rate. Data with an objective assessment parameter to this laser treatment is lacking. Objective: To evaluate the utility of melanin index in assessing the treatment response and also determine the efficacy and safety of the Q-switched Nd-Yag laser (1064-nm) in the treatment of nevus of Ota in Fitzpatrick skin types IV and V. Materials and Methods: A total of 35 patients treated with Nd-Yag laser were studied. The objective improvement (pigment clearance) was determined by melanin index from two fixed points: A1, 2 cm below the pupil at the mid pupillary line (when the gaze is fixed); A2, the most prominent part of zygoma. The melanin index in these two areas was recorded as M1 and M2, respectively. The subjective clinical improvement was determined by the physician and the patient global assessment score. Results: The mean baseline melanin indices M1 and M2 were 59.54 ± 9.72 and 59.02 ± 9.16, respectively. At the last visit the mean M1 and M2 decreased to 53.8 ± 8.55 (P 50% pigment clearance. Conclusion: The melanin index, a simple non-invasive parameter is useful in assessing the treatment response more objectively. The 1064-nm Q-switched Nd-Yag laser offers good improvement in patients with nevus of Ota in darker skin types IV/V. PMID:24470713

  4. Bioproduction, characterization, anticancer and antioxidant activities of extracellular melanin pigment produced by newly isolated microbial cell factories Streptomyces glaucescens NEAE-H

    Science.gov (United States)

    El-Naggar, Noura El-Ahmady; El-Ewasy, Sara M.

    2017-01-01

    In this present study, a newly isolated strain, Streptomyces sp. NEAE-H, capable of producing high amount of black extracellular melanin pigment on peptone-yeast extract iron agar and identified as Streptomyces glaucescens NEAE-H. Plackett–Burman statistical design was conducted for initial screening of 17 independent (assigned) variables for their significances on melanin pigment production by Streptomyces glaucescens NEAE-H. The most significant factors affecting melanin production are incubation period, protease-peptone and ferric ammonium citrate. The levels of these significant variables and their interaction effects were optimized by using face-centered central composite design. The maximum melanin production (31.650 μg/0.1 ml) and tyrosinase activity (6089.10 U/ml) were achieved in the central point runs under the conditions of incubation period (6 days), protease-peptone (5 g/L) and ferric ammonium citrate (0.5 g/L). Melanin pigment was recovered by acid-treatment. Higher absorption of the purified melanin pigment was observed in the UV region at 250 nm. It appeared to have defined small spheres by scanning electron microscopy imaging. The maximum melanin yield was 350 mg dry wt/L of production medium. In vitro anticancer activity of melanin pigment was assayed against skin cancer cell line using MTT assay. The IC50 value was 16.34 ± 1.31 μg/ml for melanin and 8.8 ± 0.5 μg/ml for standard 5-fluorouracil. PMID:28195138

  5. Optical (DRUV-VIS and magnetic (EPR behavior of synthetic melanins

    Directory of Open Access Journals (Sweden)

    Júlio César Pereira dos Santos

    2012-04-01

    Full Text Available The properties of melanins prepared from L-dopa oxidation by both chemical and electrochemical methods are reported, searching for a material with more intense optical absorption in the visible region. The characterization of the samples have been done by cyclic voltammetry (CV, cronoamperometry (CA, Fourier transformed infrared spectroscopy (FTIR, electron paramagnetic resonance spectroscopy (EPR and diffuse reflectance ultraviolet-visible spectroscopy (DRUV-VIS techniques. The electrochemical method enhanced the organic free radical (spin concentration and the absorption intensity in the visible region of the spectrum. The DRUV-VIS technique along with mathematical tools, such as the Kubelka-Munk remission function, were good options for the characterization of the final products.

  6. The progress in animal melanin%动物黑色素研究进展

    Institute of Scientific and Technical Information of China (English)

    伍革民; 彭光旭

    2005-01-01

    黑色素(melanin)是一种生物多聚体。它广泛存在于人和动物皮肤,毛发和眼睛中。动物黑色素可分为两类,一是真黑色素(eumelanin),不含硫原子,呈棕色或黑色;二是脱黑色素(pheomelanin),含硫原子,呈黄色或微红棕色。动物与人的皮肤毛发色素沉着决定于其所含真黑色素与脱黑色素的相对数量。脊椎动物黑色素的合成与酪氨酸酶(tyrosinase)密切相关。

  7. 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.

  8. Melanin Biosynthesis Inhibition Effects of Ginsenoside Rb2 Isolated from Panax ginseng Berry.

    Science.gov (United States)

    Lee, Dae Young; Jeong, Yong Tae; Jeong, Sang Chul; Lee, Mi Kyoung; Min, Jin Woo; Lee, Jae Won; Kim, Geum Soog; Lee, Seung Eun; Ahn, Young Sup; Kang, Hee Cheol; Kim, Jin Hee

    2015-12-28

    Ginsenoside Rb2 (Gin-Rb2) was purified from the fruit extract of Panax ginseng. Its chemical structure was measured by spectroscopic analysis, including HR-FAB-MS, (1)H-NMR, and IR spectroscopy. Gin-Rb2 decreased potent melanogenesis in melan-a cells, with 23.4% at 80 μM without cytotoxicity. Gin-Rb2 also decreased tyrosinase and MITF protein expression in melan-a cells. Furthermore, Gin-Rb2 presented inhibition of the body pigmentation in the zebrafish in vivo system and reduced melanin contents and tyrosinase activity. These results show that Gin-Rb2 isolated from P. ginseng may be an effective skin-whitening agent via the in vitro and in vivo systems.

  9. 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.

  10. The contribution of structural-, psittacofulvin- and melanin-based colouration to sexual dichromatism in Australasian parrots.

    Science.gov (United States)

    Taysom, A J; Stuart-Fox, D; Cardoso, G C

    2011-02-01

    Colour ornamentation in animals is exceptionally diverse, but some colours may provide better signals of individual quality or more efficient visual stimuli and, thus, be more often used as sexual signals. This may depend on physiological costs, which depend on the mechanism of colour production (e.g. exogenously acquired colouration in passerine birds appears to be most sexually dichromatic). We studied sexual dichromatism in a sample of 27 Australasian parrot species with pigment- (melanin and psittacofulvin) and structural-based colouration, to test whether some of these types of colouration are more prominent in sexual ornamentation. Unlike passerines, in which long wavelength colouration (yellow to red) usually involves exogenous and costly carotenoid pigments, yellow to red colouration in parrots is based on endogenously synthesized psittacofulvin pigments. This allows us to assess whether costly exogenous pigments are necessary for these plumage colours to have a prominent role in sexual signalling. Structural blue colouration showed the largest and most consistent sexual dichromatism, both in area and perceptually relevant chromatic differences, indicating that it is often ornamental in parrots. By contrast, we found little evidence for consistent sexual dichromatism in melanin-based colouration. Unlike passerines, yellow to red colouration was not strongly sexually dichromatic: although the area of colouration was generally larger in males, colour differences between the sexes were on average imperceptible to parrots. This is consistent with the idea that the prominent yellow to red sexual dichromatism in passerines is related to the use of carotenoid pigments, rather than resulting from sensory bias for these colours.

  11. Seasonal Changes in Colour: A Comparison of Structural, Melanin- and Carotenoid-Based Plumage Colours

    Science.gov (United States)

    Delhey, Kaspar; Burger, Claudia; Fiedler, Wolfgang; Peters, Anne

    2010-01-01

    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. PMID:20644723

  12. 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.

  13. 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 (45.70UA540nm.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 (4.46UA540nm.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.

  14. Variation in melanin content and composition in type V and VI photoexposed and photoprotected human skin: the dominant role of DHI.

    Science.gov (United States)

    Alaluf, S; Heath, A; Carter, N; Atkins, D; Mahalingam, H; Barrett, K; Kolb, R; Smit, N

    2001-10-01

    A combination of techniques, including high-performance liquid chromatography (HPLC), spectrophotometric measurements, and a novel method for quantifying melanosome morphology, were applied to the analysis of melanin content and composition in highly pigmented (Fitzpatrick type V and VI) human skin. We found that total epidermal melanin content is significantly elevated in photoexposed type V and VI skin (approximately 1.6 x), while analysis of individual melanin components suggests that pheomelanin content increases only slightly, whereas 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-eumelanin and to a greater extent 5,6-dihydroxyindole (DHI)-eumelanin content are both markedly elevated. Analysis of the relative composition of epidermal melanin in these subjects revealed that DHI-eumelanin is the largest single component (approximately 60-70%), followed by DHICA-eumelanin (25-35%), with pheomelanin being a relatively minor component (2-8%). Moreover, there was a comparative enrichment of DHI-eumelanin at photoexposed sites, with a corresponding decline in the relative contributions from DHICA-eumelanin and pheomelanin. There was also a good correlation and close agreement between the concentration of spheroidal melanosomes determined by morphological image analysis and the concentration of pheomelanin determined by a combination of HPLC and spectrophotometric analysis (r = 0.89, P DHI-eumelanin formation is the dominant pathway for melanin synthesis in heavily pigmented (Fitzpatrick V and VI) skin types in vivo, and is the favoured pathway when melanin production is increased in chronically photoexposed skin.

  15. Melanins as biomarkers of ovarian follicular atresia in the catfish Heteropneustes fossilis: biochemical and histochemical characterization, seasonal variation and hormone effects.

    Science.gov (United States)

    Kumar, Ravi; Joy, Keerikkattil P

    2015-06-01

    Follicular atresia is a common feature of the vertebrate ovary that occurs at different stages of folliculogenesis and ovarian regression. It has physiological significance to maintain homeostasis and control fecundity, and ensure removal of post-ovulatory follicular remnants for preparing the ovary for the next cycle. Pigments appear late in the atretic process as indigestible waste formed out of the degradation of the oocytes, follicle wall and granulocytes. In the present study, pigment accumulation was demonstrated by Schmorl's and Perls' staining methods in the atretic ovarian follicles of Heteropneustes fossilis during follicular development and regression. Melanins were characterized spectrophotometrically for the first time in fish ovary. The predominant form is eumelanin, followed by pheomelanin and alkali-soluble melanin. Melanins showed significant seasonal variations with levels low in gonad resting phase, increasing to the peak in the post-spawning phase. The concentration of melanins increased time-dependently in post-ovulated ovary after human chorionic gonadotropin treatment. In the spawning phase, in vitro incubation of ovary slices with estradiol-17β or dexamethasone for 8 or 16 h decreased both eumelanin and pheomelanin levels time-dependently. The alkali-soluble melanin showed a significant decrease only in the dexamethasone group at 16 h. The results show that melanin assay can be used as a biomarker of follicular atresia in fish ovary, natural or induced by environmental toxicants.

  16. Near-infrared excited state dynamics of melanins: the effects of iron content, photo-damage, chemical oxidation, and aggregate size.

    Science.gov (United States)

    Simpson, Mary Jane; Wilson, Jesse W; Robles, Francisco E; Dall, Christopher P; Glass, Keely; Simon, John D; Warren, Warren S

    2014-02-13

    Ultrafast pump-probe measurements can discriminate the two forms of melanin found in biological tissue (eumelanin and pheomelanin), which may be useful for diagnosing and grading melanoma. However, recent work has shown that bound iron content changes eumelanin's pump-probe response, making it more similar to that of pheomelanin. Here we record the pump-probe response of these melanins at a wider range of wavelengths than previous work and show that with shorter pump wavelengths the response crosses over from being dominated by ground-state bleaching to being dominated by excited-state absorption. The crossover wavelength is different for each type of melanin. In our analysis, we found that the mechanism by which iron modifies eumelanin's pump-probe response cannot be attributed to Raman resonances or differences in melanin aggregation and is more likely caused by iron acting to broaden the unit spectra of individual chromophores in the heterogeneous melanin aggregate. We analyze the dependence on optical intensity, finding that iron-loaded eumelanin undergoes irreversible changes to the pump-probe response after intense laser exposure. Simultaneously acquired fluorescence data suggest that the previously reported "activation" of eumelanin fluorescence may be caused in part by the dissociation of metal ions or the selective degradation of iron-containing melanin.

  17. Validation of Eupatorium triplinerve Vahl leaves, a skin care herb from East Kalimantan, using a melanin biosynthesis assay.

    Science.gov (United States)

    Arung, Enos Tangke; Kuspradini, Harlinda; Kusuma, Irawan Wijaya; Shimizu, Kuniyoshi; Kondo, Ryuichiro

    2012-04-01

    In searching for a new material made from natural resources that could be used as a whitening agent, we focused on the plants used for skin treatment by the native people of East Kalimantan. The methanol extract of the leaves of Eupatorium triplinerve Vahl showed antimelanogenesis activity in a melanin biosynthesis assay. By activity-guided fractionation, 7-methoxycoumarin (1) was isolated as an active compound. The IC50 of 1 on mushroom tyrosinase was 2360 μM (L-tyrosine was used as the substrate) and above 2840 μM (L-DOPA was used as the substrate), respectively. Regarding melanin formation inhibition in B16 melanoma cells, the IC50 of 1 was 1780 μM with 83% cell viability at IC50. Based on these results, we validated that the leaf extract is in line with the traditional use of the Dayak tribe in East Kalimantan.

  18. Melanin biosynthesis inhibitory and antioxidant activities of quercetin-3'-O-beta-D-glucoside isolated from Allium cepa.

    Science.gov (United States)

    Arung, Enos Tangke; Furuta, Shoko; Ishikawa, Hiroya; Tanaka, Hiroyuki; Shimizu, Kuniyoshi; Kondo, Ryuichiro

    2011-01-01

    In the course of searching for new whitening agents, we have found that the methanol extract of dried skin of Allium cepa shows potent melanin biosynthesis inhibitory activity in B16 melanoma cells. Bioassay-guided fractionation led to the isolation of quercetin-3'-O-beta-D-glucoside (1) from the methanol extract of dried skin of A. cepa, which inhibited melanin formation in B16 melanoma cells with an IC50 value of 38.8 microM and mushroom tyrosinase with an IC50 value of 6.5 microM using L-tyrosine and 48.5 microM using L-dihydroxyphenylalanine as substrates, respectively. In addition, the antioxidant activity of 1 was evaluated in the oxygen radical absorbance capacity assay; it showed 3.04 micromol Trolox equivalents/mmol. 1 was shown to be a promising ingredient that could be useful for treating hyperpigmentation and for protecting against oxidative stress.

  19. 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...

  20. 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.

  1. 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.

  2. Sex-linked inheritance, genetic correlations and sexual dimorphism in three melanin-based colour traits in the barn owl.

    Science.gov (United States)

    Roulin, A; Jensen, H

    2015-03-01

    Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.

  3. Diversion of the melanin synthetic pathway by dopamine product scavengers: A quantum chemical modeling of the reaction mechanisms

    Directory of Open Access Journals (Sweden)

    T. B. Demissie

    2017-01-01

    Full Text Available We report the stability and reactivity of the oxidation products as well as L-cysteine and N-acetylcysteine adducts of dopamine studied using quantum chemical calculations. The overall reactions studied were subdivided into four reaction channels. The first reaction channel is the oxidation of dopamine to form dopaminoquinone. The second reaction channel leads to melanin formation through subsequent reactions. The third and fourth reaction channels are reactions leading to the formation of dopaminoquinone adducts which are aimed to divert the synthesis of melanin. The results indicate that L-cysteine and N-acetylcysteine undergo chemical reactions mainly at C5 position of dopaminoquinone. The analyses of the thermodynamic energies indicate that L-cysteine and N-acetylcysteine covalently bind to dopaminoquinone by competing with the internal cyclization reaction of dopaminoquinone which leads to the synthesis of melanin. The analysis of the results, based on the reaction free energies, is also supported by the investigation of the natural bond orbitals of the reactants and products.

  4. Cladosporium cladosporioides LPSC 1088 produces the 1,8-dihydroxynaphthalene-melanin-like compound and carries a putative pks gene.

    Science.gov (United States)

    Llorente, Carla; Bárcena, Alejandra; Vera Bahima, José; Saparrat, Mario C N; Arambarri, Angélica M; Rozas, M Fernanda; Mirífico, María V; Balatti, Pedro A

    2012-12-01

    Cladosporium cladosporioides is a dematiaceous fungus with coloured mycelia and conidia due to the presence of dark pigments. The purpose of this study was to characterize the dark pigments synthetized by Cladosporium sp. LPSC no. 1088 and also to identify the putative polyketide synthase (pks) gene that might be involved in the pigment biosynthesis. Morphological as well as molecular features like the ITS sequence confirmed that LPSC 1088 is Cladosporium cladosporioides. UV-visible, Fourier Transform Infrared (FTIR) and Electron Spin Resonance (ESR) spectroscopy analysis as well as melanin inhibitors suggest that the main dark pigment of the isolate was 1,8 dihydroxynaphthalene (DHN)-melanin-type compound. Two commercial fungicides, Difenoconazole and Chlorothalonil, inhibited fungal growth as well as increased pigmentation of the colonies suggesting that melanin might protect the fungus against chemical stress. The pigment is most probably synthetized by means of a pentaketide pathway since the sequence of a 651 bp fragment, coding for a putative polyketide synthase, is highly homologous to pks sequences from other fungi.

  5. 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).

  6. 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.

  7. Control of heterogeneous nucleation and growth kinetics of dopamine-melanin by altering substrate chemistry.

    Science.gov (United States)

    Klosterman, Luke; Riley, John K; Bettinger, Christopher John

    2015-03-24

    Dopamine-melanin (DM or "polydopamine") can be deposited on virtually any substrate from solution through autoxidation of dopamine. The versatility of this process has allowed surface-mediated assembly of DM for a wide variety of functional coatings. Here we report the impact of well-defined surface chemistries on the nucleation and growth of such films. DM was deposited on silicon dioxide (SiO2) and SiO2 substrates modified with self-assembled monolayers (SAMs) bearing octadecyl (C18), phenethyl, and aminopropyl functional groups. Atomic force microscopy revealed three-dimensional islands whose areal density and surface coverage are lowest on bare SiO2 substrates and highest on the neutral aromatic and aliphatic substrates. Increasing the pH of the solution from 8.2 to 10 dissociates catechol moieties in DM and inhibits adsorption on negatively charged SiO2 substrates. The growth rate of DM films on SAM-modified SiO2 is maximized at pH 9.5 and almost completely abolished at pH 10 because of increased DM solubility. The initial rates of DM adsorption were measured using quartz crystal microbalance with dissipation measurements. The initial adsorption rate is proportional to the nucleation density, which increases as the hydrophobicity of the substrate increases. Taken together, these data provide insight into the rates of heterogeneous nucleation and growth of DM on substrates with well-defined chemistries.

  8. 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.

  9. 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.

  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. Melanin concentrating hormone induces hippocampal acetylcholine release via the medial septum in rats.

    Science.gov (United States)

    Lu, Zhi-Hong; Fukuda, Satoru; Minakawa, Yoichi; Yasuda, Atsushi; Sakamoto, Hidetoshi; Sawamura, Shigehito; Takahashi, Hidenori; Ishii, Noriko

    2013-06-01

    Among various actions of melanin concentrating hormone (MCH), its memory function has been focused in animal studies. Although MCH neurons project to various areas in the brain, one main target site of MCH is hippocampal formation for memory consolidation. Recent immunohistochemical study shows that MCH neurons directly project to the hippocampal formation and may indirectly affect the hippocampus through the medial septum nucleus (MS). It has been reported that sleep is necessary for memory and that hippocampal acetylcholine (ACh) release is indispensable for memory consolidation. However, there is no report how MCH actually influences the hippocampal ACh effluxes in accordance with the sleep-wake cycle changes. Thus, we investigated the modulatory function of intracerebroventricular (icv) injection of MCH on the sleep-wake cycle and ACh release using microdialysis techniques. Icv injection of MCH significantly increased the rapid eye movement (REM) and non-REM episode time and the hippocampal, not cortical, ACh effluxes. There was a significant correlation between REM episode time and hippocampal ACh effluxes, but not between REM episode time and cortical ACh effluxes. Microinjection of MCH into the MS increased the hippocampal ACh effluxes with no influence on the REM episode time. It appears that the effect sites of icv MCH for prolongation of REM episode time may be other neuronal areas than the cholinergic neurons in the MS. We conclude that MCH actually increases the hippocampal ACh release at least in part through the MS in rats.

  12. Histamine inhibits the melanin-concentrating hormone system: implications for sleep and arousal.

    Science.gov (United States)

    Parks, Gregory S; Olivas, Nicholas D; Ikrar, Taruna; Sanathara, Nayna M; Wang, Lien; Wang, Zhiwei; Civelli, Olivier; Xu, Xiangmin

    2014-05-15

    Melanin-concentrating hormone (MCH)-producing neurons are known to regulate a wide variety of physiological functions such as feeding, metabolism, anxiety and depression, and reward. Recent studies have revealed that MCH neurons receive projections from several wake-promoting brain regions and are integral to the regulation of rapid eye movement (REM) sleep. Here, we provide evidence in both rats and mice that MCH neurons express histamine-3 receptors (H3R), but not histamine-1 (H1R) or histamine-2 (H2R) receptors. Electrophysiological recordings in brain slices from a novel line of transgenic mice that specifically express the reporter ZsGreen in MCH neurons show that histamine strongly inhibits MCH neurons, an effect which is TTX insensitive, and blocked by the intracellular presence of GDP-β-S. A specific H3R agonist, α-methylhistamine, mimicks the inhibitory effects of histamine, and a specific neutral H3R antagonist, VUF 5681, blocks this effect. Tertiapin Q (TPQ), a G protein-dependent inwardly rectifying potassium (GIRK) channel inhibitor, abolishes histaminergic inhibition of MCH neurons. These results indicate that histamine directly inhibits MCH neurons through H3R by activating GIRK channels and suggest that that inhibition of the MCH system by wake-active histaminergic neurons may be responsible for silencing MCH neurons during wakefulness and thus may be directly involved in the regulation of sleep and arousal.

  13. Mechanisms relevant to the enhanced virulence of a dihydroxynaphthalene-melanin metabolically engineered entomopathogen.

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    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.

  14. 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

    2016-11-14

    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.

  15. 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 C28H14N2O7S. 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.

  16. HIV-Associated Oral Mucosal Melanin Hyperpigmentation: A Clinical Study in a South African Population Sample

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    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.

  17. Regulation of nucleus accumbens activity by the hypothalamic neuropeptide melanin-concentrating hormone.

    Science.gov (United States)

    Sears, Robert M; Liu, Rong-Jian; Narayanan, Nandakumar S; Sharf, Ruth; Yeckel, Mark F; Laubach, Mark; Aghajanian, George K; DiLeone, Ralph J

    2010-06-16

    The lateral hypothalamus and the nucleus accumbens shell (AcbSh) are brain regions important for food intake. The AcbSh contains high levels of receptor for melanin-concentrating hormone (MCH), a lateral hypothalamic peptide critical for feeding and metabolism. MCH receptor (MCHR1) activation in the AcbSh increases food intake, while AcbSh MCHR1 blockade reduces feeding. Here biochemical and cellular mechanisms of MCH action in the rodent AcbSh are described. A reduction of phosphorylation of GluR1 at serine 845 (pSer(845)) is shown to occur after both pharmacological and genetic manipulations of MCHR1 activity. These changes depend upon signaling through G(i/o), and result in decreased surface expression of GluR1-containing AMPA receptors (AMPARs). Electrophysiological analysis of medium spiny neurons (MSNs) in the AcbSh revealed decreased amplitude of AMPAR-mediated synaptic events (mEPSCs) with MCH treatment. In addition, MCH suppressed action potential firing MSNs through K(+) channel activation. Finally, in vivo recordings confirmed that MCH reduces neuronal cell firing in the AcbSh in freely moving animals. The ability of MCH to reduce cell firing in the AcbSh is consistent with a general model from other pharmacological and electrophysiological studies whereby reduced AcbSh neuronal firing leads to food intake. The current work integrates the hypothalamus into this model, providing biochemical and cellular mechanisms whereby metabolic and limbic signals converge to regulate food intake.

  18. High-throughput screening of novel antagonists on melanin-concentrat-ing hormone receptor-1

    Institute of Scientific and Technical Information of China (English)

    Jian-hua YAN; Qun-yi LI; Jean A BOUTIN; M Pierre RENARD; Yi-xiang DING; Xiao-jiang HAO; Wei-min ZHAO; Ming-wei WANG

    2008-01-01

    Aim: To find new antagonists on human melanin-concentrating hormone recep-tor- 1 (MCHR-1) through high-throughput screening (HTS) of a diverse com-pound library. Methods: MCHR-1, [3H]SNAP7941, and FlashBlue G-protein-coupled receptor beads were used to measure the receptor-binding activities of various compounds based on scintillation proximity assay (SPA) technology. The guanosine 5' (γ-[35S]thio) triphosphate ([35S]GTPγS) binding assay was sub-sequently applied to functionally characterize the "hits" identified by the HTS campaign. Results: Of the 48 240 compounds screened with the SPA method, 12 hits were confirmed to possess MCHR-1 binding activities, 8 were function-ally studied subsequently with the [35S]GTPγS binding assay, and only 1 com-pound (NC 127816) displayed moderate human MCHR- 1 binding affinity (Ki=115.7 nmol/L) and relatively potent antagonism (KB=23.8 nmol/L). This compound shares a novel scaffold (1-ethoxy-2H-2-aza-1-phospha-naphthalene 1-oxide) with 3 other analogs in the group. Conclusion: Considering the marked difference in molecular shape and electrostatic status between NC127816 and the structures reported elsewhere, we anticipate that its derivatives may repre-sent a new class of potent MCHR-1 modulators.

  19. Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival

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    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. 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

  1. 高粱黑粉菌黑色素生成机理及其功能研究%Melanin Formation Mechanism and Function Discussion of Sphacelotheca Reiliana

    Institute of Scientific and Technical Information of China (English)

    石太渊; 于淼; 鲁明; 高雅

    2013-01-01

    Sphacelotheca reiliana melanin is indoles macromolecular polymer and it belongs to eumelanin. It consists of the intermediate-product from indole and tyrosine oxidation. In the process of melanin biosynthesis, in addition to tyrosinase, dopachrome isomerase and DHICA oxidase also involved in the metabolism of melanin. The comprehensive effect of these three enzymes determines the biosynthesis of eumelanin. This paper mainly expounds from the structure, function, mechanism and prospects of the sphacelotheca reiliana melanin and provide a theoretical basis for the sphacelotheca reiliana melanin development.%高粱黑粉菌黑色素属于真黑色素类,是吲哚类大分子聚合体,由吲哚和酪氨酸氧化而来的中间产物构成。在黑色素的生物合成步骤中,除了酪氨酸酶,还有多巴色素异构酶和DHICA氧化酶参与黑色素代谢,这3种酶的综合作用决定了真黑色素的生物合成。主要从高粱黑粉菌黑色素的结构、功能、作用机理和前景等方面进行阐述,为高粱黑粉菌黑色素开发提供理论依据。

  2. Research progress of bacterial melanin and nervous system diseases%细菌黑色素与神经系统疾病的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨倩; 韩彦青; 姜晓萌; 裴宇恒; 李东芳; 李光来

    2016-01-01

    黑色素是广泛存在于自然界中的一类天然色素家族,苏云金芽孢杆菌突变株可获得高水平细菌黑色素,细菌黑色素能透过血脑屏障,具有抗氧化、螯合有毒金属、促进神经再生等生物学特性,可用来治疗某些与黑色素缺乏相关的神经性疾病,也能促进中枢神经系统及周围神经损伤后的结构和功能的恢复,文章就细菌黑色素在神经系统疾病的相关研究做了综述。%Melanin is a class of natural pigments family in nature. Bacterial melanin with high level of pigment synthesis-Bacillus thuringiensis was obtained. Bacterial melanin can cross the blood-brain barrier, accomplish antioxidant protection, chelate toxic metals, promote nerve regeneration. It can treat nervous system diseases with melanin deficiency, promote the structural and functional recovery of the central nervous system and peripheral nerve injury. This article summarized the research of the function of the bacterial melanin in the nervous system diseases.

  3. Impact of Solvent pH on Direct Immobilization of Lysosome-Related Cell Organelle Extracts on TiO₂ for Melanin Treatment.

    Science.gov (United States)

    Bang, Seung Hyuck; Kim, Pil; Oh, Suk-Jung; Kim, Yang-Hoon; Min, Jiho

    2015-05-01

    Techniques for immobilizing effective enzymes on nanoparticles for stabilization of the activity of free enzymes have been developing as a pharmaceutical field. In this study, we examined the effect of three different pH conditions of phosphate buffer, as a dissolving solvent for lysosomal enzymes, on the direct immobilization of lysosomal enzymes extracted from Hen's egg white and Saccharomyces cerevisiae. Titanium(IV) oxide (TiO2) nanoparticles, which are extensively used in many research fields, were used in this study. The lysosomal enzymes immobilized on TiO2 under each pH condition were evaluated to maintain the specific activity of lysosomal enzymes, so that we can determine the degree of melanin treatment in lysosomal enzymes immobilized on TiO2. We found that the immobilization efficiency and melanin treatment activity in both lysosomal enzymes extracted from Hen's egg white and S. cerevisiae were the highest in an acidic condition of phosphate buffer (pH 4). However, the immobilization efficiency and melanin treatment activity were inversely proportional to the increase in pH under alkaline conditions. In addition, enhanced immobilization efficiency was shown in TiO2 pretreated with a divalent, positively charged ion, Ca(2+), and the melanin treatment activity of immobilized lysosomal enzymes on TiO2 pretreated with Ca(2+) was also increased. Therefore, this result suggests that the immobilization efficiency and melanin treatment activity of lysosomal enzymes can be enhanced according to the pH conditions of the dissolving solvent.

  4. Sleep architecture and homeostasis in mice with partial ablation of melanin-concentrating hormone neurons.

    Science.gov (United States)

    Varin, Christophe; Arthaud, Sébastien; Salvert, Denise; Gay, Nadine; Libourel, Paul-Antoine; Luppi, Pierre-Hervé; Léger, Lucienne; Fort, Patrice

    2016-02-01

    Recent reports support a key role of tuberal hypothalamic neurons secreting melanin concentrating-hormone (MCH) in the promotion of Paradoxical Sleep (PS). Controversies remain concerning their concomitant involvement in Slow-Wave Sleep (SWS). We studied the effects of their selective loss achieved by an Ataxin 3-mediated ablation strategy to decipher the contribution of MCH neurons to SWS and/or PS. Polysomnographic recordings were performed on male adult transgenic mice expressing Ataxin-3 transgene within MCH neurons (MCH(Atax)) and their wild-type littermates (MCH(WT)) bred on two genetic backgrounds (FVB/N and C57BL/6). Compared to MCH(WT) mice, MCH(Atax) mice were characterized by a significant drop in MCH mRNAs (-70%), a partial loss of MCH-immunoreactive neurons (-30%) and a marked reduction in brain density of MCH-immunoreactive fibers. Under basal condition, such MCH(Atax) mice exhibited higher PS amounts during the light period and a pronounced SWS fragmentation without any modification of SWS quantities. Moreover, SWS and PS rebounds following 4-h total sleep deprivation were quantitatively similar in MCH(Atax)vs. MCH(WT) mice. Additionally, MCH(Atax) mice were unable to consolidate SWS and increase slow-wave activity (SWA) in response to this homeostatic challenge as observed in MCH(WT) littermates. Here, we show that the partial loss of MCH neurons is sufficient to disturb the fine-tuning of sleep. Our data provided new insights into their contribution to subtle process managing SWS quality and its efficiency rather than SWS quantities, as evidenced by the deleterious impact on two powerful markers of sleep depth, i.e., SWS consolidation/fragmentation and SWA intensity under basal condition and under high sleep pressure.

  5. Chronic loss of melanin-concentrating hormone affects motivational aspects of feeding in the rat.

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    Joram D Mul

    Full Text Available Current epidemic obesity levels apply great medical and financial pressure to the strenuous economy of obesity-prone cultures, and neuropeptides involved in body weight regulation are regarded as attractive targets for a possible treatment of obesity in humans. The lateral hypothalamus and the nucleus accumbens shell (AcbSh form a hypothalamic-limbic neuropeptide feeding circuit mediated by Melanin-Concentrating Hormone (MCH. MCH promotes feeding behavior via MCH receptor-1 (MCH1R in the AcbSh, although this relationship has not been fully characterized. Given the AcbSh mediates reinforcing properties of food, we hypothesized that MCH modulates motivational aspects of feeding.Here we show that chronic loss of the rat MCH-precursor Pmch decreased food intake predominantly via a reduction in meal size during rat development and reduced high-fat food-reinforced operant responding in adult rats. Moreover, acute AcbSh administration of Neuropeptide-GE and Neuropeptide-EI (NEI, both additional neuropeptides derived from Pmch, or chronic intracerebroventricular infusion of NEI, did not affect feeding behavior in adult pmch(+/+ or pmch(-/- rats. However, acute administration of MCH to the AcbSh of adult pmch(-/- rats elevated feeding behavior towards wild type levels. Finally, adult pmch(-/- rats showed increased ex vivo electrically evoked dopamine release and increased limbic dopamine transporter levels, indicating that chronic loss of Pmch in the rat affects the limbic dopamine system.Our findings support the MCH-MCH1R system as an amplifier of consummatory behavior, confirming this system as a possible target for the treatment of obesity. We propose that MCH-mediated signaling in the AcbSh positively mediates motivational aspects of feeding behavior. Thereby it provides a crucial signal by which hypothalamic neural circuits control energy balance and guide limbic brain areas to enhance motivational or incentive-related aspects of food consumption.

  6. Melanin-concentrating hormone (MCH: role in REM sleep and depression

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    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.

  7. 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

  8. 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.

  9. Estradiol differently affects melanin synthesis of malignant and normal melanocytes: a relationship with clock and clock-controlled genes.

    Science.gov (United States)

    Poletini, Maristela Oliveira; de Assis, Leonardo Vinicius Monteiro; Moraes, Maria Nathalia; Castrucci, Ana Maria de Lauro

    2016-10-01

    Melanin production within melanocytes is regulated, among others, by estradiol, whose effects on melanogenesis are still not completely elucidated. Here we show that although 10(-7) M 17β-estradiol (E2) increased tyrosinase mRNA levels in B16-F10 malignant melanocytes, there was a transient decrease and abolishment of the temporal variation of melanin content. Both parameters were much higher in the malignant than in normal Melan-a cells. Considering that silencing clock machinery in human melanocytes increases melanogenesis, we investigated clock gene expression in those cell lines. Except for Melan-a Bmal1 and B16-F10 Per2 expression of control cells, Per1, Per2, and Bmal1 expression increased independently of cell type or E2 treatment after 24 h. However, melanoma cells showed a marked increase in Per1 and Bma11 expression in response to E2 at the same time points, what may rule out E2 as a synchronizer agent since the expression of those genes were not in antiphase. Next, we investigated the expression of Xpa, a clock-controlled gene, which in Melan-a cells, peaked at 18 h, and E2 treatment shifted this peak to 24 h, whereas B16-F10 Xpa expression peaked at 24 h in both control and E2 group, and it was higher compared to Melan-a cells in both groups. Therefore, malignant and normal melanocytes display profound differences on core elements of the local clock, and how they respond to E2, what is most probably determinant of the differences seen on melanin synthesis and Tyrosinase and Xpa expression. Understanding these processes at the molecular level could bring new strategies to treat melanoma.

  10. Statistical approach, Sensory analysis, brief application of Bioinformatics Tool, Melanin, Allicin and Glucosinolate presence in Mango pulp for Pharmacological Benefits

    Directory of Open Access Journals (Sweden)

    Saranya Chitturi

    2013-06-01

    Full Text Available Information on important flavor components for fruit and vegetables is lacking and would be useful for breeders and molecular biologists . In this study five acid treatments, were formulated and the effects of Citric Acid (CA and Malic Acid (MA levels on canned mango pulp (Mangifera indica L. flavor perception was evaluated . Depiction of pulp components was executed in the Rasmol V 2 7.1 visualizing pectin, melanin and allinase compounds as a part of brief bioformatic analysis of the pulp. Melanin content, allicin and glucosinolate’s presence were assessed and their % concentration variations against different treatments was depicted . As we correlated the values of TSS and pH by different statistical analysis methods like Pearson’s correlation coefficient, Spearman’s and Regression plots by a statistical software we found that these two variables are positively correlated to each other. We have the alternate hypothesis H1 with p value < 0.05 being accepted for the sensory quality estimation based on Larmond’s 9-point hedonic scale sensory evaluation. The lowest levels of allicin was found in T2 about 0.14% where as the highest was noted to be about 4.28% in T3. The T5 treatment showed low concentration of melanin about 3.98% and the highest was about 9.43% in T4.The glucosinolate concentrations also varied according to the treatment administered. Low level of about 3.34% in T3 and about 7.9% concentration was observed in T4 . All these findings can further invariably help in extending the shelf life and increasing the marketability of the mango based products

  11. Oxidative stress regulated heme-oxygenase-1 and glutathione S-transferase-m1 gene expression changes in cell lines exposed to melanins

    Institute of Scientific and Technical Information of China (English)

    Jie Li; Peng Zhao; Junfeng Yang; Renyun Zhang; Shen Li; Dan Liu

    2011-01-01

    To investigate the effects of oxidative stress on substantia nigra neuronal degeneration and death in patients with Parkinson's disease, we treated neuroblastoma cells (SK-N-SH) and glioma cells with Fenton's reagent, iron chelating agent, neuromelanin and dopamine melanin. We investigated the changes in expression of nine oxidative stress-related genes and proteins. The levels of mRNAs for heme-oxygenase-1 and glutathione S-transferase-m1 were significantly reduced in SK-N-SH cells exposed to oxidative stress, and increased in glial cells treated with deferoxamine. These results revealed that SK-N-SH neurons react sensitively to oxidative stress, which implies different outcomes between these two types of cells in the substantia nigra. Moreover, the influences of neuromelanin and dopamine melanin on cell function are varied, and dopamine melanin is not a good model for neuromelanin.

  12. Alisol B, a triterpene from Alismatis rhizoma (dried rhizome of Alisma orientale), inhibits melanin production in murine B16 melanoma cells.

    Science.gov (United States)

    Yoshida, Ichiro; Ito, Chihiro; Matsuda, Shinya; Tsuji, Akihiko; Yanaka, Noriyuki; Yuasa, Keizo

    2017-03-01

    To develop new whitening agents from natural products, we screened 80 compounds derived from crude drugs in Kampo medicine in a melanin synthesis inhibition assay using murine B16 melanoma cells. The screen revealed that treatment with alisol B, a triterpene from Alismatis rhizoma, significantly decreased both melanin content and cellular tyrosinase activity in B16 cells. However, alisol B did not directly inhibit mushroom tyrosinase activity in vitro. Therefore, we investigated the mechanism underlying the inhibitory effect of alisol B on melanogenesis. Alisol B suppressed mRNA induction of tyrosinase and its transcription factor, microphthalmia-associated transcription factor (MITF). Furthermore, alisol B reduced the phosphorylation of CREB and maintained the activation of ERK1/2. These results suggest that the reduction in melanin production by alisol B is due to the downregulation of MITF through the suppression of CREB and activation of ERK and that alisol B may be useful as a new whitening agent.

  13. 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.

  14. Ultrastructure and Antioxidative Activity of Melanin from Cuttlefish%乌贼墨黑色素的超微结构及抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    李和生; 李晓; 董亚辉; 雷静; 孙楠楠; 张丽媛

    2012-01-01

    应用电镜技术和体外培养试验等研究乌贼墨黑色素超微结构及其抗氧化等特性.结果表明,乌贼墨黑色素是由黑色素单体堆积而成,其单体颗粒呈圆形,表面清晰光滑,平均直径约118 nm.乌贼墨黑色素对大肠杆菌有较好的光保护效果.随着黑色素浓度的增加,其光保护作用增强.黑色素可有效抑制猪油的氧化反应.在乌贼墨黑色素同一添加量水平下,POV值均随着时间的延长而增大;在一定时间条件下,乌贼墨添加量越大,POV值越小,表明乌贼墨黑色素具有较强的抗氧化能力.黑色素对大鼠自发性脂质过氧化有明显的抑制作用,其抑制率达到53.3%.同时,黑色素对Fe2+-Cys诱导大鼠肝脂质过氧化也有较明显的抑制作用,其抑制率达到22.5%.%The ultrastruclure and antioxidation of melanin from cuttlefish were dealt with electron microscope technology and incubation in Vitro. The results were showed that the cuttlefish melanin was consisted hy the accumulation of the melanin monomers. The shape of monomer grain with mean diameter of about 0.118 μm was round, clear and smooth. The photoprotective effect of cuttlefish melanin to E. Coli was better and was increased with the melanin concentration. The oxidation of lard can be efficiently restrained by the cuttlefish melanin. POV (peroxide value) increased with time in the same addition of the cuttlefish melanin, but decreased with the addition in the same time. Those showed that the cuttlefish melanin had stronger, antioxidation ability. The restriction of endogenous LPO(lipid peroxidation) to rat liver homogenate was obvious and its inhibitory rate could reach to be 53.3%. Meanwhile, the restriction of Fe2+-Cys-induced LPO was also obvious and the inhibitory rate reached 22.5%.

  15. EPR Studies of DOPA–Melanin Complexes with Netilmicin and Cu(II) at Temperatures in the Range of 105–300 K

    OpenAIRE

    Zdybel, Magdalena; Pilawa, Barbara; Buszman, Ewa; Wrześniok, Dorota; Krzyminiewski, Ryszard; Kruczyński, Zdzisław

    2012-01-01

    The application of electron paramagnetic resonance (EPR) spectroscopy in pharmacy of melanin complexes with netilmicin and Cu(II) was presented. The continuous microwave saturation of EPR spectra of DOPA–melanin and the complexes was performed. EPR spectra were measured on an X-band (9.3 GHz) spectrometer at temperatures in the range of 105–300 K. Paramagnetic copper ions decrease the intensity of the EPR lines of melanin’s free radicals. It was found that fast spin–lattice relaxation charact...

  16. 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

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  17. Effects of Danshensu and Salvianolic Acid B from Salvia miltiorrhiza Bunge (Lamiaceae) on cell proliferation and collagen and melanin production.

    Science.gov (United States)

    Chen, Yi-Shyan; Lee, Shu-Mei; Lin, Ying-Ju; Chiang, Shu-Hua; Lin, Chih-Chien

    2014-02-13

    Danshensu (DSU) and salvianolic acid B (SAB) are the primary water-soluble compounds of Salvia miltiorrhiza Bunge (Lamiaceae). In this study, we analyzed the effects of DSU, SAB and a S. miltiorrhiza extract (SME) on cell proliferation. Additionally, the effects of DSU and SAB on collagen synthesis in Detroit 551 human normal fibroblast cells and on melanin production in B16 melanoma cells were verified. The results demonstrated that SME can enhance the proliferation of Detroit 551 cells and that this boost may be caused by DSU and SAB. This research showed that SME, DSU and SAB all have the ability to increase the production of collagen in Detroit 551 cells. The results also confirmed that DSU and SAB can attenuate the α-MSH-stimulated melanin production of B16 cells by inhibiting tyrosinase activity. Therefore, SME, DSU and SAB each have the potential to be utilized as active ingredients in wound healing or cosmetic treatments. In the future, DSU and SAB could also be used as functional components for treating hyperpigmentation.

  18. Effects of Danshensu and Salvianolic Acid B from Salvia miltiorrhiza Bunge (Lamiaceae on Cell Proliferation and Collagen and Melanin Production

    Directory of Open Access Journals (Sweden)

    Yi-Shyan Chen

    2014-02-01

    Full Text Available Danshensu (DSU and salvianolic acid B (SAB are the primary water-soluble compounds of Salvia miltiorrhiza Bunge (Lamiaceae. In this study, we analyzed the effects of DSU, SAB and a S. miltiorrhiza extract (SME on cell proliferation. Additionally, the effects of DSU and SAB on collagen synthesis in Detroit 551 human normal fibroblast cells and on melanin production in B16 melanoma cells were verified. The results demonstrated that SME can enhance the proliferation of Detroit 551 cells and that this boost may be caused by DSU and SAB. This research showed that SME, DSU and SAB all have the ability to increase the production of collagen in Detroit 551 cells. The results also confirmed that DSU and SAB can attenuate the α-MSH-stimulated melanin production of B16 cells by inhibiting tyrosinase activity. Therefore, SME, DSU and SAB each have the potential to be utilized as active ingredients in wound healing or cosmetic treatments. In the future, DSU and SAB could also be used as functional components for treating hyperpigmentation.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 从藜豆中提取天然黑色素的工艺研究%Study on the extraction of natural melanin from mucuna macrocarpa wall

    Institute of Scientific and Technical Information of China (English)

    陈松; 韦万兴; 刘志平; 周敏; 卓家雄; 肖世基

    2011-01-01

    The extraction of natural melanin from mucuna macrocarpa wall was studied. Based on the experiment, the melanin was suitable to be extracted with 4% NaOH at 60 t for 40 min,precipitated when pH was 2. After further purification,3.62% yield of melanin was obtained. With UV and IR analysis,the melanin has the structure model of catechol.%以我国南方资源丰富的藜豆为原料,对藜豆中的天然黑色素提取工艺进行了研究,得出了藜豆黑色素的最佳提取条件:用4% NaOH溶液于60℃超声浸提40 min,调节pH =2,析出黑色素,得率为3.62%.由紫外和红外波谱分析藜豆黑色素具有邻苯二酚型结构.

  4. The hypothalamo-hypophyseal system of the white seabream Diplodus sargus: immunocytochemical identification of arginine-vasotocin, isotocin, melanin-concentrating hormone and corticotropin-releasing factor.

    Science.gov (United States)

    Duarte, G; Segura-Noguera, M M; Martín del Río, M P; Mancera, J M

    2001-01-01

    The distribution of the neurosecretory hormones vasotocin, isotocin and melanin-concentrating hormone and the hypophysiotropic hormone corticotropin-releasing factor was studied in the hypothalamo-hypophyseal system of the white seabream (Diplodus sargus) using immunocytochemical techniques. Magnocellular and parvocellular perikarya immunoreactive for arginine-vasotocin and isotocin were present in the nucleus preopticus. Perikarya immunoreactive for arginine-vasotocin extended more caudally with respect to isotocin-immunoreactive perikarya. Parvocellular perikarya were located at rostroventral levels and magnocellular perikarya in the dorsocaudal portion of the nucleus. Arginine-vasotocin and isotocin did not coexist in the same neuron. Fibres immunoreactive for arginine-vasotocin and isotocin innervated all areas of neurohypophysis and terminate close to corticotropic and melanotropic cells. Perikarya immunoreactive for melanin-concentrating hormone and corticotropin-releasing factor were observed in the nucleus lateralis tuberis, with a few neurons in the nucleus periventricularis posterior. In addition, melanin-concentrating hormone immunoreactive perikarya were detected in the nucleus recessus lateralis. The preoptic nucleus did not show immunoreactivity for these antisera. Fibres showing melanin-concentrating hormone and corticotropin-releasing factor immunoreactivity ended close to the melanotropic and somatolactotrophic cells of the pars intermedia, and close to the corticotrophic cells of the rostral pars distalis.

  5. Manassantin A inhibits cAMP-induced melanin production by down-regulating the gene expressions of MITF and tyrosinase in melanocytes.

    Science.gov (United States)

    Lee, Hwa Dong; Lee, Won-Hee; Roh, Eunmiri; Seo, Chang-Seob; Son, Jong-Keun; Lee, Seung Ho; Hwang, Bang Yeon; Jung, Sang-Hun; Han, Sang-Bae; Kim, Youngsoo

    2011-09-01

    Microphthalmia-associated transcription factor (MITF) is inducible in response to cAMP through the cAMP-responsive element-binding protein (CREB) and plays a pivotal role in the melanocyte-specific expression of tyrosinase or tyrosinase-related proteins (TRPs) for melanin biosynthesis. Manassantin A from Saururus chinensis inhibits cAMP-induced melanin production in B16 melanoma cells. Here, we focused on molecular basis of the antimelanogenic activity. Manassantin A consistently inhibited the cAMP elevator 3-isobutyl-1-methylxanthine (IBMX)- or dibutyryl cAMP-induced melanin production in B16 cells or in melan-a melanocytes by down-regulating the expression of tyrosinase or TRP1 gene. Moreover, manassantin A suppressed MITF induction through IBMX-activated CREB pathway, directly inhibiting the Ser-133 phosphorylation of CREB. However, manassantin A did not affect IBMX-increased cAMP levels in these cells but also other cAMP-dependent melanogenic pathways through post-translational modifications of MITF. This putative molecular mechanism of manassantin A in the inhibition of melanin production suggests its pharmacological potential in skin hyperpigmentation.

  6. 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...

  7. Study on antioxidant activities of melanin of Aureobasidium pullulans%出芽短梗霉黑色素的抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    赵博; 乔长晟; 汪建明; 盖丽丰

    2013-01-01

    In order to evaluate the antioxidant activities of melanin in Aureobasidium pullulans, reaction systems of reducing force, DPPH free radicals, hydroxyl free radicals, super oxide anion free radicals, iron chela force as well as inhibition of lipid peroxidation were established. Then antioxidant activities of melanin of Aureobasidium pullulans and Vc were measured and compared in different reaction systems. The result indicated that melanin had certain reductive force, in 0.4g/L was equal to the Vc. Melanin could effectively scavenge DPPH free radicals, hydroxyl free radicals and super oxide anion free radicals. Under the condition of the same concentration, melanin remove hydroxyl free radicals and super oxide anion free radicals were higher than Vc. In addition, melanin had certain iron ion chelated force and suppress the lipid peroxidation ability. So, melanin in Aureobasidium pullulans had good antioxidant activities.%建立了还原力体系、DPPH自由基体系、羟基自由基体系、超氧阴离子自由基体系、铁离子螯合力体系及抑制脂质过氧化体系.以VC作为参照,研究了出芽短梗霉黑色素在不同体系下的抗氧化活性.结果表明,黑色素具有一定的还原能力,在浓度为0.4g/L时,其还原力与VC相当,黑色素对羟自由基、超氧阴离子自由基、DPPH自由基均有较好的清除作用,同等浓度条件下黑色素清除羟自由基和超氧阴离子的能力均高于VC.此外,黑色素具有一定的铁离子螯合能力和抑制脂质过氧化能力.综上所述,黑色素具有一定的抗氧化活性.

  8. In vitro binding studies of drugs to hair: influence of melanin and lipids on cocaine binding to Caucasoid and Africoid hair.

    Science.gov (United States)

    Joseph, R E; Su, T P; Cone, E J

    1996-10-01

    Although the mechanism(s) of drug deposition in hair are unknown, there is evidence that suggests that the amount and type of melanin present are major factors in determining how much drug enters hair after exposure. The role of other hair components, such as lipids, has received less attention. We used in vitro binding techniques to evaluate the binding of radiolabeled cocaine to different types of treated and untreated hair specimens. Divided male and female Caucasoid (black/brown and blond colored) and Africoid (black colored) hair specimens (N = 7) were exhaustively extracted to remove lipid components (lipid-extracted hair). Separate portions were bleached to denature or alter melanin content. Experiments with radiolabeled cocaine were performed on untreated, lipid-extracted, and bleached portions of hair from different groups. Cocaine binding was significantly higher (p hair compared with other groups. The amount of drug binding was similar among female Africoid and male and female, black/brown Caucasoid specimens. The lowest amount of binding was observed with blond, female Caucasoid specimens. Binding experiments also revealed that specific cocaine binding generally did not differ significantly between lipid-extracted hair and untreated hair, but bleaching of most hair specimens resulted in significant (p hair. In separate experiments with cocaine-treated hair specimens, digested samples were evaluated to determine if removal of the insoluble melanin fraction from soluble hair components provided a means of normalization of drug content and elimination of color bias. Removal of the insoluble melanin fraction was not effective in removal of significant amounts of cocaine, which indicated that the digestion process released bound cocaine into the digest solution. Overall, these experiments suggested that lipids in hair play a minor role in drug binding, whereas melanin functions as a major binding site for cocaine. Natural (ethnic) or artificial (bleaching

  9. 维生素对黑色素代谢的影响%Effects of Vitamins on Melanin Metabolism

    Institute of Scientific and Technical Information of China (English)

    李虎; 刘志军

    2013-01-01

      黑色素是人及动物皮肤或者毛发中存在的一种黑褐色的生物色素,是皮肤为避免受紫外线等的伤害而自行产生的一种保护性色素。遗传易感性、过度暴露在阳光下以及其他来源的紫外线均会破坏皮肤的抗氧化能力,影响黑素细胞合成黑素颗粒,引起皮肤色素相关疾病。现有研究表明皮肤中的抗氧化因子能有效保护机体免受紫外线的危害,维生素作为抗氧化物质已广泛应用于临床,本文概述了维生素B、维生素E、维生素C和维生素D等抗氧化维生素通过不同的抗氧化机制影响着黑色素代谢而应用于皮肤色素相关疾病的治疗,以期为维生素治疗色素疾病提供理论依据。%Melanin is a dark brown biological pigment which exists in human skin or hair, also in animal;protect the damage of UV rays. Genetic susceptibility, excessive exposure to sun’s rays and other sources of ultraviolet ray will damage the skin antioxidant capacity of the skin,then influence the melanin granules of melanocyte, cause pigment related skin diseases. Recent studies show that skin antioxidant factor can effectively protect the body from harmful UV rays, vitamins as antioxidants have been widely used in clinical practice. This article provides an overview of the antioxidant vitamins, including vitamin B, vitamin E, vitamin C and vitamin D, which affect the metabolism of melanin through different anti-oxidation mechanisms,and applied to the skin pigment disease treatment, in the hope of providing theoretical basis for the treatment of pigmentary disorders with vitamins.

  10. The leaf extract of Mallotus japonicus and its major active constituent, rutin,suppressed on melanin production in murine B16F1 melanoma简

    Institute of Scientific and Technical Information of China (English)

    Junsei; Taira; Eito; Tsuchida; Masatsugu; Uehara; Natsuko; Ohhama; Wakana; Ohmine; Takayuki; Ogi

    2015-01-01

    Objective: To find anti-melanogenesis materials used in whitening cosmetics.Methods: The ethanolic leaf extract of Mallotus japonicus(M. japonicus) having an anti-melanogenesis activity was separated by a sephadex LH-20 chromatography. Each fraction was measured for its tyrosinase inhibitory activity together with its polyphenol content using the Folin–Ciocalteu method. The anti-melanogenesis activity of the active fractions was determined by the melanin content in the murine B16F1 melanoma. The active fractions were put together due to similar constituents, and then separated by high performance liquid chromatography using a C-18 ODS column. The major antimelanogenesis compound was identified using1 H and13C-NMR and liquid chromatography-mass spectrometry.Results: The ethanolic leaf extract of M. japonicus showed an anti-tyrosinase activity with a high polyphenol content, resulting in suppression of melanin production in the B16F1 melanoma. The extract was separated and the active compound was identical as rutin based on the1 H,13C-NMR and liquid chromatography-mass spectrometry analysis data. In addition, the rutin treatment with cells reduced the melanin content in a concentration dependent manner without any cell toxicity. The leaf extract of M. japonicus containing rutin would be useful in whitening cosmetics for protection from UV-light exposure to be limiting the accumulation of melanin in skin.Conclusions: The leaf extract of M. japonicus and/or rutin isolated from the extract as a key whitening agent would be useful as a whitening cosmetic material for protecting against disorder skin due to melanin accumulation.

  11. The leaf extract ofMallotus japonicus and its major active constituent, rutin, suppressed on melanin production in murine B16F1 melanoma

    Institute of Scientific and Technical Information of China (English)

    Junsei Taira; Eito Tsuchida; Masatsugu Uehara; Natsuko Ohhama; Wakana Ohmine; Takayuki Ogi

    2015-01-01

    Objective:To find anti-melanogenesis materials used in whitening cosmetics. Methods: The ethanolic leaf extract ofMallotus japonicus (M. japonicus) having an anti-melanogenesis activity was separated by a sephadexLH-20 chromatography. Each fraction was measured for its tyrosinase inhibitory activity together with its polyphenol content using the Folin–Ciocalteu method. The anti-melanogenesis activity of the active fractions was determined by the melanin content in the murine B16F1 melanoma. The active fractions were put together due to similar constituents, and then separated by high performance liquid chromatography using a C-18 ODS column. The major anti-melanogenesis compound was identified using 1Hand13C-NMR and liquid chromatography-mass spectrometry. Results: The ethanolic leaf extract ofM. japonicus showed an anti-tyrosinase activity with a high polyphenol content, resulting in suppression of melanin production in the B16F1 melanoma. The extract was separated and the active compound was identical as rutin based on the1H,13C-NMR and liquid chromatography-mass spectrometry analysis data. In addition, the rutin treatment with cells reduced the melanin content in a concentration dependent manner without any cell toxicity. The leaf extract ofM. japonicus containing rutin would be useful in whitening cosmetics for protection from UV-light exposure to be limiting the accumulation of melanin in skin. Conclusions: The leaf extract ofM. japonicus and/or rutin isolated from the extract as a key whitening agent would be useful as a whitening cosmetic material for protecting against disorder skin due to melanin accumulation.

  12. Preparation and characterization of a novel Al(18)F-NOTA-BZA conjugate for melanin-targeted imaging of malignant melanoma.

    Science.gov (United States)

    Chang, Chih-Chao; Chang, Chih-Hsien; Lo, Yi-Hsuan; Lin, Ming-Hsien; Shen, Chih-Chieh; Liu, Ren-Shyan; Wang, Hsin-Ell; Chen, Chuan-Lin

    2016-08-15

    Melanin is an attractive target for the diagnosis and treatment of malignant melanoma. Previous studies have demonstrated the specific binding ability of benzamide moiety to melanin. In this study, we developed a novel (18)F-labeled NOTA-benzamide conjugate, Al(18)F-NOTA-BZA, which can be synthesized in 30min with a radiochemical yield of 20-35% and a radiochemical purity of >95%. Al(18)F-NOTA-BZA is highly hydrophilic (logP=-1.96) and shows good in vitro stability. Intravenous administration of Al(18)F-NOTA-BZA in two melanoma-bearing mouse models revealed highly specific uptake in B16F0 melanotic melanoma (6.67±0.91 and 1.50±0.26%ID/g at 15 and 120min p.i., respectively), but not in A375 amelanotic melanoma (0.87±0.21 and 0.24±0.09%ID/g at 15 and 120min p.i., respectively). The clearance from most normal tissues was fast. A microPET scan of Al(18)F-NOTA-BZA-injected mice also displayed high-contrast tumor images as compared with normal organs. Owing to the favorable in vivo distribution of Al(18)F-NOTA-BZA after intravenous administration, the estimated absorption dose was low in all normal organs and tissues. The melanin-specific binding ability, sustained tumor retention, fast normal tissues clearance and thelow projected human dosimetry supported that Al(18)F-NOTA-BZA is a very promising melanin-specific PET probe for melanin-positive melanoma.

  13. 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.

  14. Towards the development of a novel bioinspired functional material: synthesis and characterization of hybrid TiO2/DHICA-melanin nanoparticles.

    Science.gov (United States)

    Pezzella, Alessandro; Capelli, Luigia; Costantini, Aniello; Luciani, Giuseppina; Tescione, Fabiana; Silvestri, Brigida; Vitiello, Giuseppe; Branda, Francesco

    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 TiO2. Two synthesis procedures were carried out to get DHICA-melanin coated TiO2 nanoparticles as well as mixed DHICA/TiO2 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 TiO2 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 10nm. DHICA-melanin does act as a morphological agent affecting morphology of hybrid nanostructures. XRD analysis proved that TiO2 hybrid nanoparticles kept anatase structures for DHICA-melanin contents within the range of investigated compositions, i.e. up to 50% wt/wt.

  15. 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.

  16. The repeat domain of the melanosome fibril protein Pmel17 forms the amyloid core promoting melanin synthesis.

    Science.gov (United States)

    McGlinchey, Ryan P; Shewmaker, Frank; McPhie, Peter; Monterroso, Begoña; Thurber, Kent; Wickner, Reed B

    2009-08-18

    Pmel17 is a melanocyte protein necessary for eumelanin deposition 1 in mammals and found in melanosomes in a filamentous form. The luminal part of human Pmel17 includes a region (RPT) with 10 copies of a partial repeat sequence, pt.e.gttp.qv., known to be essential in vivo for filament formation. We show that this RPT region readily forms amyloid in vitro, but only under the mildly acidic conditions typical of the lysosome-like melanosome lumen, and the filaments quickly become soluble at neutral pH. Under the same mildly acidic conditions, the Pmel filaments promote eumelanin formation. Electron diffraction, circular dichroism, and solid-state NMR studies of Pmel17 filaments show that the structure is rich in beta sheet. We suggest that RPT is the amyloid core domain of the Pmel17 filaments so critical for melanin formation.

  17. Screening for cardiovascular safety: a structure-activity approach for guiding lead selection of melanin concentrating hormone receptor 1 antagonists.

    Science.gov (United States)

    Kym, Philip R; Souers, Andrew J; Campbell, Thomas J; Lynch, John K; Judd, Andrew S; Iyengar, Rajesh; Vasudevan, Anil; Gao, Ju; Freeman, Jennifer C; Wodka, Dariusz; Mulhern, Mathew; Zhao, Gang; Wagaw, Seble H; Napier, James J; Brodjian, Sevan; Dayton, Brian D; Reilly, Regina M; Segreti, Jason A; Fryer, Ryan M; Preusser, Lee C; Reinhart, Glenn A; Hernandez, Lisa; Marsh, Kennan C; Sham, Hing L; Collins, Christine A; Polakowski, James S

    2006-04-06

    An inactin-anesthetized rat cardiovascular (CV) assay was employed in a screening mode to triage multiple classes of melanin-concentrating hormone receptor 1 (MCHr1) antagonists. Lead identification was based on a compound profile producing high drug concentration in both plasma (>40 microM) and brain (>20 microg/g) with optimization activities on multiple classes of MCHr1 antagonists were terminated. After providing evidence that the cardiovascular liabilities were not a function of MCHr1 antagonism, continued screening identified the chromone-substituted aminopiperidine amides as a class of MCHr1 antagonists that demonstrated a safe cardiovascular profile at high drug concentrations in both plasma and brain. The high incidence of adverse cardiovascular effects associated with an array of MCHr1 antagonists of significant chemical diversity, combined with the stringent safety requirements for antiobesity drugs, highlight the importance of incorporating cardiovascular safety assessment early in the lead selection process.

  18. Whey peptides prevent chronic ultraviolet B radiation-induced skin aging in melanin-possessing male hairless mice.

    Science.gov (United States)

    Kimura, Yoshiyuki; Sumiyoshi, Maho; Kobayashi, Toshiya

    2014-01-01

    Whey proteins or peptides exhibit various actions, including an antioxidant action, an anticancer action, and a protective action against childhood asthma and atopic syndrome. The effects of orally administered whey peptides (WPs) on chronic ultraviolet B (UVB) radiation-induced cutaneous changes, including changes in cutaneous thickness, elasticity, wrinkle formation, etc., have not been examined. In this study, we studied the preventive effects of WPs on cutaneous aging induced by chronic UVB irradiation in melanin-possessing male hairless mice (HRM). UVB (36-180 mJ/cm(2)) was irradiated to the dorsal area for 17 wk in HRM, and the measurements of cutaneous thickness and elasticity in UVB irradiated mice were performed every week. WPs (200 and 400 mg/kg, twice daily) were administered orally for 17 wk. WPs inhibited the increase in cutaneous thickness, wrinkle formation, and melanin granules and the reduction in cutaneous elasticity associated with photoaging. Furthermore, it has been reported that UVB irradiation-induced skin aging is closely associated with the increase in expression of matrix metalloproteinase (MMP), vascular endothelial growth factor (VEGF), Ki-67-, and 8-hydroxy-2'-deoxyguanosine (8-OHdG)-positive cells. WPs also prevented increases in the expression of MMP-2 and pro-MMP-9, VEGF, and Ki-67- and 8-OHdG-positive cells induced by chronic UVB irradiation. It was found that WPs prevent type IV collagen degradation, angiogenesis, proliferation, and DNA damage caused by UVB irradiation. Overall, these results demonstrate the considerable benefit of WPs for protection against solar UV-irradiated skin aging as a supplemental nutrient.

  19. 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.

  20. 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.

  1. Optimization of extraction process of the melanin from prickly ash seed%花椒籽中黑色素提取工艺的优化研究

    Institute of Scientific and Technical Information of China (English)

    徐文秀; 王晓燕; 王鹏

    2013-01-01

    In order to improve the economy value of prickly ash seed and fully use of its by-products, the melanin was extracted from prickly ash seed by solvents.Effects of different factors,such as extraction solvent,extraction solvent concentration,extraction temperature,extraction time,ratio of solid to liquid and extraction times on melanin yield of prickly ash seed were studied by single factor test.Absorbance was selected as a substitute of melanin content.Based on single factor test,response surface analysis methodology was used to determine the optimal extraction conditions of melanin.Response surface analysis indicated that:optimal extraction conditions were 66℃, 4.5h,1:33(g/mL).The absorbance value of the melanin obtained was 0.305.The order of three factors affecting melanin yield from prickly ash seed was:temperature > ratio of solid to liquor Mime.%为了提高花椒的经济价值,充分利用花椒下脚料,以山西运域花椒籽为原料,采用溶剂法对花椒籽中的黑色素进行提取.通过单因素实验对影响花椒籽黑色素得率的因素:提取溶剂、提取溶剂浓度、提取温度、提取时间、料液比、提取次数进行探讨,用花椒籽黑色素提取液的吸光值来代替黑色素含量.在单因素实验的基础上,应用Box-Behnken 中心组合设计建立数学模型,以花椒籽黑色素提取液的吸光值作为响应值,进行响应面法分析(RSM),得出黑色素提取最佳工艺条件参数结果表明,最优工艺参数为:最佳提取温度为66℃,最佳提取时间4.5h,料液比1∶33 (g/mL).此条件下,黑色素吸光值为0.305.三个因素对花椒籽黑色素得率影响依次为:温度>料液比>时间.

  2. Study of Extracting Condition of Fungal Melanin%真菌菌丝黑色素提取条件的研究

    Institute of Scientific and Technical Information of China (English)

    杨一艳; 李明锐; 包龙丽; 何永美

    2012-01-01

    [Objective] The research aimed to extract the fungal melanin better. [Method] The effects of the particle size (30,60,100 and 140 mesh) of fungal mycelium and 3 kinds of extraction conditions at high temperature (121℃ and 20 min in high-pressure sterilization pot,boiling water bath for 2 h and boiling water bath for 5 h) on the extraction of fungal melanin were studied. [ Result] No significant influence of the particle size of fungal mycelium on the extraction of fungal melanin was found. The content of fungal melanin was extracted by boiling water bath for 5 h was significantly higher than that by 121 ℃ and 20 min in high-pressure sterilization pot or by boiling water bath for 2 h. RSD and recovery rate of fungal melanin extracted from fungal mycelium of 30 mesh by boiling water bath for 5 h was 0. 5% -3.0% and 86.0% - 123.0% respectively. [ Conclusion] The method was feasible for the extraction of fungal melanin from fungal mycelium of 30 mesh by 1 mol/L NaOH with boiling water bath for 5 h.%[目的]为了更好地提取真菌黑色素.[方法]比较了菌丝粒径(30、60、100和140目)和3种高温提取条件(高压灭菌锅内121℃20 min、沸水浴2 h和沸水浴5h)提取真菌黑色素的效果.[结果]菌丝粒径对黑色素提取效果影响不显著.沸水浴5h提取不同粒径菌丝黑色素的含量在0.01水平显著高于其余2个高温提取条件.沸水浴5h提取30目菌丝黑色素含量的RSD为0.5%~3.0%,黑色素加标回收率为86.0% ~ 123.0%.[结论]1 mol/L NaOH沸水浴5h提取30目菌丝中的黑色素是较好的提取方法.

  3. Research of extraction and property of melanin from fermented soy sauce%发酵酱油色素的提取及性质研究

    Institute of Scientific and Technical Information of China (English)

    郭彩华; 陈昭华; 孙莉萍; 卢珍华; 杨秋明

    2012-01-01

    用有机溶剂从生抽酱油中提取酱油色素,研究其理化性质。结果表明:酱油色素的得率为17.8g/100mL,其为棕褐色带有浓郁酱香味的固形物。紫外和红外光谱扫描结果显示酱油色素是美拉德反应和酶促褐变的产物。酱油色素容易被H2O2氧化,而亚硫酸钠、蔗糖、苯甲酸钠和山梨酸钾对色素的影响很小,说明酱油色素稳定性良好。色素对DPPH自由基的清除能力可达88%,对羟基自由基的清除能力达80%,抑制亚硝胺合成的抑制率可达80%。%The melanin was extracted from light fermented soy sauce by organic solvent,and its physical and chemical properties were studied.Results showed that 17.8g soy sauce melanin could be obtained from 100mL uncooked soy sauce,and it was a chocolate brown solid with a rich sauce flavor.UV-Vis and infrared spectra revealed that the soy sauce melanin was products of the Maillard reaction and enzymatic browning.The melanin could be oxidized easily by H2O2.But Na2SO3,sucrose,sodium benzoate and potassium sorbate had little effect on it,soy sauce melanin had a good stability.Scavenging effect of the melanin on DPPH free radicals and on hydroxyl free radicals were 88% and 80%,respectively.Blocking action on synthesis of nitrosamine was up to 80%.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Melanin is not required for turgor generation but enhances cell-wall rigidity in appressoria of the corn pathogen Colletotrichum graminicola.

    Science.gov (United States)

    Ludwig, Nancy; Löhrer, Marco; Hempel, Marcus; Mathea, Sebastian; Schliebner, Ivo; Menzel, Matthias; Kiesow, Andreas; Schaffrath, Ulrich; Deising, Holger B; Horbach, Ralf

    2014-04-01

    The ascomycete and causative agent of maize anthracnose and stem rot, Colletotrichum graminicola, differentiates melanized infection cells called appressoria that are indispensable for breaching the plant cell wall. High concentrations of osmolytes accumulate within the appressorium, and the internal turgor pressure of up to 5.4 MPa provides sufficient force to penetrate the leaf epidermis directly. In order to assess the function of melanin in C. graminicola appressoria, we identified and characterized the polyketide synthase 1 (CgPKS1) gene which displayed high similarity to fungal polyketide synthases (PKS) involved in synthesis of 1,3,6,8-tetrahydronaphthalene, the first intermediate in melanin biosynthesis. Cgpks1 albino mutants created by targeted gene disruption were unable to penetrate intact leaves and ruptured frequently but, surprisingly, were able to penetrate ultrathin polytetrafluoroethylene membranes mimicking the plant surface. Nonmelanized Cgpks1 appressoria were sensitive to externally applied cell-wall-degrading enzymes whereas melanized appressoria were not affected. Expression studies using a truncated CgPKS1 fused to green fluorescent protein revealed fluorescence in immature appressoria and in setae, which is in agreement with transcript data obtained by RNA-Seq and quantitative polymerase chain reaction. Unexpectedly, surface scans of mutant and wild-type appressoria revealed considerable differences in cell-wall morphology. Melanization of appressoria is indispensable for successful infection of intact leaves. However, cell collapse experiments and analysis of the appressorial osmolyte content by Mach-Zehnder interferometry convincingly showed that melanin is not required for solute accumulation and turgor generation, thus questioning the role of melanin as a barrier for osmolytes in appressoria of C. graminicola.

  9. 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.

  10. Molecular imaging of melanin distribution in vivo and quantitative differential diagnosis of human pigmented lesions using label-free harmonic generation biopsy (Conference Presentation)

    Science.gov (United States)

    Sun, Chi-Kuang; Wei, Ming-Liang; Su, Yu-Hsiang; Weng, Wei-Hung; Liao, Yi-Hua

    2017-02-01

    Harmonic generation microscopy is a noninvasive repetitive imaging technique that provides real-time 3D microscopic images of human skin with a sub-femtoliter resolution and high penetration down to the reticular dermis. In this talk, we show that with a strong resonance effect, the third-harmonic-generation (THG) modality provides enhanced contrast on melanin and allows not only differential diagnosis of various pigmented skin lesions but also quantitative imaging for longterm tracking. This unique capability makes THG microscopy the only label-free technique capable of identifying the active melanocytes in human skin and to image their different dendriticity patterns. In this talk, we will review our recent efforts to in vivo image melanin distribution and quantitatively diagnose pigmented skin lesions using label-free harmonic generation biopsy. This talk will first cover the spectroscopic study on the melanin enhanced THG effect in human cells and the calibration strategy inside human skin for quantitative imaging. We will then review our recent clinical trials including: differential diagnosis capability study on pigmented skin tumors; as well as quantitative virtual biopsy study on pre- and post- treatment evaluation on melasma and solar lentigo. Our study indicates the unmatched capability of harmonic generation microscopy to perform virtual biopsy for noninvasive histopathological diagnosis of various pigmented skin tumors, as well as its unsurpassed capability to noninvasively reveal the pathological origin of different hyperpigmentary diseases on human face as well as to monitor the efficacy of laser depigmentation treatments. This work is sponsored by National Health Research Institutes.

  11. Bioinspired near-infrared-excited sensing platform for in vitro antioxidant capacity assay based on upconversion nanoparticles and a dopamine-melanin hybrid system.

    Science.gov (United States)

    Wang, Dong; Chen, Chuan; Ke, Xuebin; Kang, Ning; Shen, Yuqing; Liu, Yongliang; Zhou, Xi; Wang, Hongjun; Chen, Changqing; Ren, Lei

    2015-02-11

    A novel core-shell structure based on upconversion fluorescent nanoparticles (UCNPs) and dopamine-melanin has been developed for evaluation of the antioxidant capacity of biological fluids. In this approach, dopamine-melanin nanoshells facilely formed on the surface of UCNPs act as ultraefficient quenchers for upconversion fluorescence, contributing to a photoinduced electron-transfer mechanism. This spontaneous oxidative polymerization of the dopamine-induced quenching effect could be effectively prevented by the presence of various antioxidants (typically biothiols, ascorbic acid (Vitamin C), and Trolox). The chemical response of the UCNPs@dopamine-melanin hybrid system exhibited great selectivity and sensitivity toward antioxidants relative to other compounds at 100-fold higher concentration. A satisfactory correlation was established between the ratio of the "anti-quenching" fluorescence intensity and the concentration of antioxidants. Besides the response of the upconversion fluorescence signal, a specific evaluation process for antioxidants could be visualized by the color change from colorless to dark gray accompanied by the spontaneous oxidation of dopamine. The near-infrared (NIR)-excited UCNP-based antioxidant capacity assay platform was further used to evaluate the antioxidant capacity of cell extracts and human plasma, and satisfactory sensitivity, repeatability, and recovery rate were obtained. This approach features easy preparation, fluorescence/visual dual mode detection, high specificity to antioxidants, and enhanced sensitivity with NIR excitation, showing great potential for screening and quantitative evaluation of antioxidants in biological systems.

  12. The metabolism and influence factors of skin melanin%皮肤黑素的代谢及其影响因素

    Institute of Scientific and Technical Information of China (English)

    王娟; 马慧群

    2011-01-01

    人类皮肤颜色的各种差异与黑素细胞中黑素小体的数目、大小、类型和分布有着直接的关系.黑素的合成及其在细胞内的转运是非常复杂而精确的过程,该过程决定皮肤色素的分布与沉着.有诸多因素影响着黑素的代谢,目前研究较多的有酪氨酸酶、过氧化物酶、微量元素、紫外线、结构蛋白Pmel 17和蛋白受体2等.%The skin color of human is diversity, there is a close relation between the quantity, magnitude, type, distribution of melanosome in melanocytes. The synthesis of melanin and the intercellular transportation of melanin are complicated which as a precise process determines the distribution and skin pigmentation. There are many factors influencing the metabolism of skin melanin, such as tyrosinase, peroxidase, microelement, ultraviolet rays, structural proteins 17 and protein receptor 2.

  13. 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.

  14. DHN melanin biosynthesis in the plant pathogenic fungus Botrytis cinerea is based on two developmentally regulated key enzyme (PKS)-encoding genes.

    Science.gov (United States)

    Schumacher, Julia

    2016-02-01

    Botrytis cinerea is the causal agent of gray mold disease in various plant species and produces grayish macroconidia and/or black sclerotia at the end of the infection cycle. It has been suggested that the pigmentation is due to the accumulation of 1,8-dihydroxynaphthalene (DHN) melanin. To unravel its basis and regulation, the putative melanogenic and regulatory genes were identified and functionally characterized. Unlike other DHN melanin-producing fungi, B. cinerea and other Leotiomycetes contain two key enzyme (PKS)-encoding enzymes. Bcpks12 and bcpks13 are developmentally regulated and are required for melanogenesis in sclerotia and conidia respectively. BcYGH1 converts the BcPKS13 product and contributes thereby to conidial melanogenesis. In contrast, enzymes acting downstream in conversion of the PKS products (BcBRN2, BcSCD1 and BcBRN1) are required for both, sclerotial and conidial melanogenesis, suggesting that DHN melanogenesis in B. cinerea follows a non-linear pathway that is rather unusual for secondary metabolic pathways. Regulation of the melanogenic genes involves three pathway-specific transcription factors (TFs) that are clustered with bcpks12 or bcpks13 and other developmental regulators such as light-responsive TFs. Melanogenic genes are dispensable in vegetative mycelia for proper growth and virulence. However, DHN melanin is considered to contribute to the longevity of the reproduction structures.

  15. Roles of reactive oxygen species in UVA-induced oxidation of 5,6-dihydroxyindole-2-carboxylic acid-melanin as studied by differential spectrophotometric method.

    Science.gov (United States)

    Ito, Shosuke; Kikuta, Marina; Koike, Shota; Szewczyk, Grzegorz; Sarna, Michal; Zadlo, Andrzej; Sarna, Tadeusz; Wakamatsu, Kazumasa

    2016-05-01

    Eumelanin photoprotects pigmented tissues from ultraviolet (UV) damage. However, UVA-induced tanning seems to result from the photooxidation of preexisting melanin and does not contribute to photoprotection. We investigated the mechanism of UVA-induced degradation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-melanin taking advantage of its solubility in a neutral buffer and using a differential spectrophotometric method to detect subtle changes in its structure. Our methodology is suitable for examining the effects of various agents that interact with reactive oxygen species (ROS) to determine how ROS is involved in the UVA-induced oxidative modifications. The results show that UVA radiation induces the oxidation of DHICA to indole-5,6-quinone-2-carboxylic acid in eumelanin, which is then cleaved to form a photodegraded, pyrrolic moiety and finally to form free pyrrole-2,3,5-tricarboxylic acid. The possible involvement of superoxide radical and singlet oxygen in the oxidation was suggested. The generation and quenching of singlet oxygen by DHICA-melanin was confirmed by direct measurements of singlet oxygen phosphorescence.

  16. 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.

  17. sAPP as a regulator of dendrite motility and melanin release in epidermal melanocytes and melanoma cells.

    Science.gov (United States)

    Quast, Thomas; Wehner, Sven; Kirfel, Gregor; Jaeger, Klaus; De Luca, Michele; Herzog, Volker

    2003-09-01

    Numerous factors including ultraviolet (UV) radiation and growth factors regulate the specific function of epidermal melanocytes. A recently discovered epidermal growth factor is sAPP, the soluble N-terminal ectodomain of the beta-amyloid precursor protein (APP). Using whole mount preparations of isolated human epidermis, we detected a small population of basal cells, which expressed exceptionally high levels of APP. These cells were identified as melanocytes, which, similar to keratinocytes and neuronal cells, expressed the three APP isoforms 695, 751, and 770. They differed in their expression pattern from that of neuronal cells by expressing only low levels of APP 695. Melanocytes and melanoma cells in vitro released, in addition to keratinocytes, large quantities of sAPP. Because of its growth factor function, we studied possible effects of sAPP on melanocytes. Recombinant sAPP strongly increased lamellipodia activity at dendritic tips, an effect that coincided with increased release of melanin particles. Our observations point to the possible use of APP as an immunocytochemical marker for melanocytes. They suggest that sAPP derived from keratinocytes and/or melanocytes belongs to a family of factors operating in the paracrine and/or autocrine regulation of melanocyte function.

  18. Biological Activities of QIAPI 1 as a Melanin Precursor and Its Therapeutic Effects in Wistar Rats Exposed to Arsenic Poisoning.

    Science.gov (United States)

    Solís-Herrera, Arturo; Ashraf, Ghulam M; del C A Esparza, María; Arias, Ruth I S; Bachurin, Sergei O; Barreto, George E; Aliev, Gjumrakch

    2015-01-01

    The chemical process initiated by QIAPI 1 has been deemed to be the most important biological reaction associated with human photosynthesis, and possibly neuroprotective effects under various inflammatory events. However, the detailed biological activities of QIAPI 1 as a melanin precursor are still unknown. In the present work, cytotoxicity test was done by MTT assay to determine cell viability of various cell lines (WI-38, A549, HS 683) like proliferation tests and its effect on cytokine production. Arsenic poisoning is an often-unrecognized cause of renal insufficiency. No prophylactic and/or therapeutic compounds have shown promising results against kidney diseases. The pathogenesis of Arsenic-induced nephropathy is not clear. Arsenic, as itself, does not degrade over time in the environment, and its accumulation may induce toxic effects. In this study, we also report the histological findings of the kidney in 3 groups of Wistar rats, a control group, a group exposed to arsenic in the water; and a group exposed to arsenic and treated with QIAPI 1 simultaneously. The findings of the current evidence indicates a potential therapeutic ability of QIAPI 1.

  19. 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.

  20. Melanin-originated carbonaceous dots for triple negative breast cancer diagnosis by fluorescence and photoacoustic dual-mode imaging.

    Science.gov (United States)

    Xiao, Wei; Li, Yuan; Hu, Chuan; Huang, Yuan; He, Qin; Gao, Huile

    2017-07-01

    Carbonaceous dots exhibit increasing applications in diagnosis and drug delivery due to excellent photostability and biocompatibility properties. However, relative short excitation and emission of melanin carbonaceous dots (MCDs) limit the applicability in fluorescence bioimaging. Furthermore, the generally poor spatial resolution of fluorescence imaging limits potential in vivo applications. Due to a variety of beneficial properties, in this study, MCDs were prepared exhibiting great potential in fluorescence and photoacoustic dual-mode bioimaging. The MCDs exhibited a long excitation peak at 615nm and emission peak at 650nm, further highlighting the applicability in fluorescence imaging, while the absorbance peak at 633nm renders MCDs suitable for photoacoustic imaging. In vivo, the photoacoustic signal of MCDs was linearly correlated with the concentration of MCDs. Moreover, the MCDs were shown to be taken up into triple negative breast cancer cell line 4T1 in both a time- and concentration-dependent manner. In vivo fluorescence and photoacoustic imaging of subcutaneous 4T1 tumor demonstrated that MCDs could passively target triple negative breast cancer tissue by enhanced permeability and retention effects and may therefore be used for tumor dual-mode imaging. Furthermore, fluorescence distribution in tissue slices suggested that MCDs may distribute in 4T1 tumor with high efficacy. In conclusion, the MCDs studied offer potential application in fluorescence and photoacoustic dual-mode imaging.

  1. Effective tracking of bone mesenchymal stem cells in vivo by magnetic resonance imaging using melanin-based gadolinium(3+) nanoparticles.

    Science.gov (United States)

    Cai, Wen-Wen; Wang, Ling-Jie; Li, Si-Jin; Zhang, Xi-Ping; Li, Ting-Ting-; Wang, Ying-Hua; Yang, Xi; Xie, Jun; Li, Jian-Ding; Liu, Shi-Jie; Xu, Wen; He, Sheng; Cheng, Zhen; Fan, Qu-Li; Zhang, Rui-Ping

    2017-01-01

    Tracking transplanted stem cells is necessary to clarify cellular properties and improve transplantation success. In this study, we designed and synthesized melanin-based gadolinium(3+) (Gd(3+) )-chelate nanoparticles (MNP-Gd(3+) ) of ∼7 nm for stem cell tracking in vivo. MNP-Gd(3+) possesses many beneficial properties, such as its high stability and sensitivity, shorter T1 relaxation time, higher cell labeling efficiency, and lower cytotoxicity compared with commercial imaging agents. We found that the T1 relaxivity (r1 ) of MNP-Gd(3+) was significantly higher than that of Gd-DTPA; the nanoparticles were taken up by bone mesenchymal stem cells (BMSCs) via endocytosis and were broadly distributed in the cytoplasm. Based on an in vitro MTT assay, no cytotoxicity of labeled stem cells was observed for MNP-Gd(3+) concentrations of less than 800 µg/mL. Furthermore, we tracked MNP-Gd(3+) -labeled BMSCs in vivo using 3.0T MRI equipment. After intramuscular injection, MNP-Gd(3+) -labeled BMSCs were detected, even after four weeks, by 3T MRI. We concluded that MNP-Gd(3+) nanoparticles at appropriate concentrations can be used to effectively monitor and track BMSCs in vivo. MNP-Gd(3+) nanoparticles have potential as a new positive MRI contrast agent in clinical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 131-137, 2017.

  2. Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes.

    Science.gov (United States)

    Devi, Sulochana; Markandeya, Yogananda; Maddodi, Nityanand; Dhingra, Anuradha; Vardi, Noga; Balijepalli, Ravi C; Setaluri, Vijayasaradhi

    2013-05-01

    Mutations in TRPM1, a calcium channel expressed in retinal bipolar cells and epidermal melanocytes, cause complete congenital stationary night blindness with no discernible skin phenotype. In the retina, TRPM1 activity is negatively coupled to metabotropic glutamate receptor 6 (mGluR6) signaling through Gαo and TRPM1 mutations result in the loss of responsiveness of TRPM1 to mGluR6 signaling. Here, we show that human melanocytes express mGluR6, and treatment of melanocytes with L-AP4, a type III mGluR-selective agonist, enhances Ca(2+) uptake. Knockdown of TRPM1 or mGluR6 by shRNA abolished L-AP4-induced Ca(2+) influx and TRPM1 currents, showing that TRPM1 activity in melanocytes is positively coupled to mGluR6 signaling. Gαo protein is absent in melanocytes. However, forced expression of Gαo restored negative coupling of TRPM1 to mGluR6 signaling, but treatment with pertussis toxin, an inhibitor of Gi /Go proteins, did not affect basal or mGluR6-induced Ca(2+) uptake. Additionally, chronic stimulation of mGluR6 altered melanocyte morphology and increased melanin content. These data suggest differences in coupling of TRPM1 function to mGluR6 signaling explain different cellular responses to glutamate in the retina and the skin.

  3. Melanin precursor 5,6-dihydroxyindol: protective effects and cytotoxicity on retinal cells in vitro and in vivo.

    Science.gov (United States)

    Heiduschka, Peter; Blitgen-Heinecke, Petra; Tura, Aysegül; Kokkinou, Despina; Julien, Sylvie; Hofmeister, Sabine; Bartz-Schmidt, Karl Ulrich; Schraermeyer, Ulrich

    2007-12-01

    5,6-dihydroxyindole (DHI) is a melanin pigment precursor with antioxidant properties. In the light of a report about cytotoxicity of DHI, the aim of this study was to assess possible toxic effects of DHI on cells related to the eye, such as human ARPE-19 cells and mouse retinal explants. Moreover, DHI was tested on its effects on retinal function in vivo using electroretinography. We found cytotoxicity of DHI against ARPE-19 cells at 100 microM, but not at 10 microM. 10 microM DHI exhibited a slight, though not significant protective activity against UV-A damage in ARPE-19 cells. We found cytoprotection in cultured mouse retinas by 50 microM DHI or its diacetylated derivative 5,6-diacetoxyindole (DAI), respectively. In ERG measurements in vivo, amplitudes were decreased only slightly by 100 microM DHI compared to saline, whereas a better preservation of amplitudes was visible at 10 microM DHI, in particular with respect to cones. In histological sections, more cones were found at 10 microM DHI than at 100 microM DHI. As a conclusion, DHI shows a slight protective effect at 10 microM both in vitro and in vivo. At 100 microM, it shows a strong cytotoxicity in vitro, which is strongly reduced in vivo.

  4. Biochemical effects of the flavanol-rich lychee fruit extract on the melanin biosynthesis and reactive oxygen species.

    Science.gov (United States)

    Hagiwara, Kazuya; Okura, Masae; Sumikawa, Yasuyuki; Hida, Tokimasa; Kuno, Atsushi; Horio, Yoshiyuki; Yamashita, Toshiharu

    2016-10-01

    An ingredient of fruit polyphenol, resveratrol, is known to have an inhibitory effect on melanogenesis. In order to examine the functional differences between resveratrol and other fruit polyphenols, we compared biochemical effects of a resveratrol-free polyphenol, flavanol-rich lychee fruit extract (FRLFE), with other phenolic compounds including resveratrol. FRLFE as well as hydroquinone and resveratrol suppressed growth of B16F1 melanoma cells more significantly than rhododendrol or arbutin. Resveratrol suppressed mushroom tyrosinase at the lowest concentration (23.0 μmol/L) among the compounds tested. FRLFE and hydroquinone suppressed tyrosinase at almost the same concentration (half maximal inhibitory concentration [IC50 ], 83.5 and 94.6 μmol/L, respectively), which was higher than rhododendrol, ascorbic acid and arbutin (IC50 , 245, 345 and 421 μmol/L, respectively). Western blot analysis revealed that although resveratrol decreased expressions of tyrosinase and tyrosinase-related protein 1, FRLFE did not affect their expressions. Both FRLFE and resveratrol suppressed antimycin A-mediated reactive oxygen species (ROS) production in melanocytic cells. Resveratrol-mediated ROS suppression was inhibited by nicotinamide, a SIRT1 inhibitor. However, FRLFE-mediated suppression was not affected by nicotinamide. Moreover, FRLFE directly decreased superoxide in vitro, as detected by superoxide dismutase-like scavenging activity assay. These results suggest that FRLFE can protect melanocytes from cytotoxicity caused by an excess amount of melanin and ROS in a different manner from resveratrol.

  5. A comparison of diode laser and Er:YAG lasers in the treatment of gingival melanin pigmentation.

    Science.gov (United States)

    Simşek Kaya, Göksel; Yapici Yavuz, Günay; Sümbüllü, Muhammed A; Dayi, Ertunç

    2012-03-01

    This study compared the use of diode and Er:YAG lasers in treating gingival melanin pigmentation (GMP) in terms of gingival depigmentation, local anesthesia requirements, postoperative pain/discomfort, depigmentation effectiveness, and total treatment duration. Twenty patients (13 female, 7 male) referred with GMP were enrolled in the study. Patients were randomly divided into 2 groups. Group 1 was treated with a gallium aluminum arsenide diode laser with a continuous wavelength of 808 nm, and group 2 was treated with an Er:YAG laser with a continuous wavelength of 2,940 nm. Gingival depigmentation was performed by applying the laser at 1 W. Treatment was administered on a weekly basis until a normal pink gingival color was observable in clinical examination and photographs. In addition, patients were asked to evaluate the procedure by using a self-administered questionnaire. Procedures were carried out without the need for any topical or local anesthetic, and no unpleasant events occurred during the actual procedure or the healing period. The total length of treatment was significantly shorter with the diode laser (group 1) than with the Er:YAG laser (group 2; P lasers administered at 1 W both result in satisfactory depigmentation of GMP. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Inhibitory effect of p-coumaric acid by Rhodiola sachalinensis on melanin synthesis in B16F10 cells.

    Science.gov (United States)

    Park, So-Hee; Kim, Dong-Seok; Park, Seo-Hyoung; Shin, Jung-Won; Youn, Sang-Woong; Park, Kyoung-Chan

    2008-04-01

    Rhodiola has been widely used in traditional Asian medicine. In this study, we tested the hypopigmentation effects of R. sachalinensis and its active compounds including catechin, chlorogenic acid, p-coumaric acid, and p-tyrosol. Results have shown that only p-coumaric acid inhibits melanin synthesis in B16F10 cells. However, p-coumaric acid did not inhibit tyrosinase activity when L-DOPA was used as a substrate. Instead, p-coumaric acid inhibited tyrosinase activity when L-tyrosine was used as a substrate. We further analyzed the changes of cAMP responsive element binding protein (CREB) phosphorylation and tyrosinase gene expression. The results indicate that p-coumaric acid does not affect CREB phosphorylation or tyrosinase protein production. In turn, these findings demonstrate that p-coumaric acid has no effect on the upstream regulation of tyrosinase gene expression, although p-coumaric acid showed a significant inhibitory effect on melanogenesis. Because p-coumaric acid showed different effects on tyrosinase activity according to different substrates, we tested whether tyrosinase can utilize p-coumaric acid as a substrate. Our findings revealed that competitive inhibition occurs between p-coumaric acid and tyrosine. Consequently, this finding could be a primary mechanism for the hypopigmenting action of p-coumaric acid.

  7. Cinnamomum cassia essential oil inhibits α-MSH-induced melanin production and oxidative stress in murine B16 melanoma cells.

    Science.gov (United States)

    Chou, Su-Tze; Chang, Wen-Lun; Chang, Chen-Tien; Hsu, Shih-Lan; Lin, Yu-Che; Shih, Ying

    2013-09-18

    Essential oils extracted from aromatic plants exhibit important biological activities and have become increasingly important for the development of aromatherapy for complementary and alternative medicine. The essential oil extracted from Cinnamomum cassia Presl (CC-EO) has various functional properties; however, little information is available regarding its anti-tyrosinase and anti-melanogenic activities. In this study, 16 compounds in the CC-EO have been identified; the major components of this oil are cis-2-methoxycinnamic acid (43.06%) and cinnamaldehyde (42.37%). CC-EO and cinnamaldehyde exhibited anti-tyrosinase activities; however, cis-2-methoxycinnamic acid did not demonstrate tyrosinase inhibitory activity. In murine B16 melanoma cells stimulated with α-melanocyte-stimulating hormone (α-MSH), CC-EO and cinnamaldehyde not only reduced the melanin content and tyrosinase activity of the cells but also down-regulated tyrosinase expression without exhibiting cytotoxicity. Moreover, CC-EO and cinnamaldehyde decreased thiobarbituric acid-reactive substance (TBARS) levels and restored glutathione (GSH) and catalase activity in the α-MSH-stimulated B16 cells. These results demonstrate that CC-EO and its major component, cinnamaldehyde, possess potent anti-tyrosinase and anti-melanogenic activities that are coupled with antioxidant properties. Therefore, CC-EO may be a good source of skin-whitening agents and may have potential as an antioxidant in the future development of complementary and alternative medicine-based aromatherapy.

  8. 棕榈纤维黑色素提取工艺及性质%Extraction technology and characterization of melanin from Palm fiber

    Institute of Scientific and Technical Information of China (English)

    方丽梅; 刘星星; 江颖; 王蜀; 张同华

    2016-01-01

    Mixed acid and alcohol were used to extract the palm fiber melanin,the extraction process was optimized and the basic properties of the palm fiber were studied. The one-factor-at-a-time and orthogonal array design methods were used to optimize the ex-traction technology of palm fiber melanin. The optimum extraction temperature,extraction time,ratio of solid to liquid,the volume fac-tion of alcohol and the ratio of acid and alcohol were 80 ℃,4 hours,25 g/ mL,80% and 2: 8,and the crude extract yield reached up to 34. 64% under these optimum conditions. The UV and infrared spectral characterization indicated that the melanin had a structure i-dentical to that of synthetic melanin. The palm fiber melanin was soluble in alkaline solution,but insoluble in water,acid solution and organic solvents.%采用盐酸和乙醇混合液为提取液对棕榈纤维黑色素进行提取并优化其提取工艺,对其基本性质进行了研究.结果表明,最佳提取条件为提取时间4 h、提取温度80℃、料液质量比1:25、乙醇的体积分数80%、盐酸乙醇体积比2:8,此时黑色素得率为34.64%.红外光谱图和紫外吸收光谱图表明,棕榈纤维黑色素的结构特征与合成黑色素基本一致,棕榈纤维黑色素溶于碱液但不溶于水、酸及一般的有机溶剂.

  9. Optimization of Extraction Process for Melanin Pigment from Apricot Kernel Skin%杏仁种皮黑色素提取工艺优化

    Institute of Scientific and Technical Information of China (English)

    李巨秀; 李红姣; 赵忠; 夏秋敏; 朱海兰

    2012-01-01

    Melanin is a kind of complex polymeric phenolic compound,which can be used in the field of medicine,cosmetics,food and electron.In this work,melanin was extracted from apricot kernel skin by alkaline extraction,acid hydrolysis,and repeated precipitation,and one-factor-at-a-time and orthogonal array design methods were used to optimize four extraction conditions including NaOH concentration,extraction temperature,extraction time and material-to-liquid ratio based on melanin yield.Three extraction conditions except extraction time had a highly significant effect on melanin yield(P 0.01),and could be ranked in descending order of importance as follows: extraction temperature NaOH concentration material-to-liquid ratio.The optimal extraction conditions were NaOH concentration of 0.4 mol/L,extraction temperature of 80 ℃,and extraction duration of 6 h,and material-to-liquid ratio of 1:20.Under these conditions,the yield of melanin was 7.2%.%以杏仁种皮为试验材料,采用碱溶解酸沉淀的方法提取黑色素,以氢氧化钠溶液浓度、提取温度、提取时间、料液比为考察因素,以黑色素得率为指标,通过单因素和正交试验,研究山杏种皮黑色素的提取工艺。结果表明:氢氧化钠浓度、提取温度、料液比3个因素对黑色素的得率均表现出极显著(P〈0.01)影响;3个因素对黑色素提取得率影响的主次顺序为提取温度〉氢氧化钠浓度〉料液比;最佳工艺为氢氧化钠浓度0.4mol/L、提取温度80℃、提取时间6h、料液比1:20(g/mL),黑色素得率达到7.2%。

  10. Role of ocular melanin in ocular drug delivery%眼内色素在眼部药物传递中的作用

    Institute of Scientific and Technical Information of China (English)

    兰碧菲

    2014-01-01

    Ocular melanin is mainly distributed in the uveal tract (including iris,ciliary body and choroid) and the retina pigmented epithelial (RPE) layer.Many drugs from different therapeutic classes can bind to melanin.Examples include antibiotics,anesthetics,β-blockers,corticosteroids,antimalarial drugs and so on.The critical factors are the acid/base status and the lipophilicity of the molecule.Lots of literatures,which refer to pharmacokinetic and pharmacodynamics of drugs from different administration routes,have demonstrated that the binding of drugs to melanin plays an important role in the drug delivery.Not only it may increase initial concentration of drug in the tissues,but also the reversible binding of most drugs to melanin result in a slow release of drugs from melanin,thus it would prolong the action time to potentially beneficial or adverse effects.In addition,the melanin content differs by species and races,even by regions of an eye,which results in different binding capacity of a drug in each individual.Nonetheless,further understanding the melanin-drug binding can provide scientific insight and guideline for transscleral ocular drug delivery.%眼内色素主要存在于葡萄膜(包括虹膜、睫状体、脉络膜)和视网膜色素上皮(RPE)层,它能与很多不同类型的药物结合,如抗生素、麻醉剂、β-受体阻滞剂、糖皮质激素和抗疟药等,结合的关键在于药物的酸碱度和脂溶性.通过研究药物在不同给药途径中的药代动力学和药效学,发现眼内色素与药物的结合在眼部药物传递中起重要的作用.它不仅可以提高药物在组织中的初始浓度,而且色素与大部分药物的结合是可逆的,使得药物可以从色素中缓慢释放而延长药物的作用时间,产生有利或不利的影响.由于不同的药物与色素的结合力不同,且在不同的物种和种族,甚至同一组织的不同区域中眼内色素的含量都有区别,使得药物与色素的结合

  11. 黑木耳天然黑色素理化性质及其抗氧化活性的研究%Physicochemical properties and antioxidant activities of Auricularia auricula melanin

    Institute of Scientific and Technical Information of China (English)

    邹宇; 尹冬梅; 胡文忠; 姜爱丽; 陈晨; 顾振新

    2013-01-01

    The physicochemical properties and antioxidant activities of Auricularia auricula(A.auricula)melanin were studied.The result showed that Aauricula melanin powder was dark with a little red and yellow colored( L* =41.03, a* =2.26, b* =3.78).The solubility properties of A.auricula melanin were very similar to those of the typical melanin.A auricula melanin possessed a stronger thermal stability and pigment retention rate was 88.0% after heating at 100℃ for 4h.Whereas, A auricula melanin was sensitive to light and pigment retention rate was only 25.3% when irradiation for 5d by natural light.A auricula melanin exhibited a strong antioxidant activity.At concentration of l.Omg/mL, hydroxyl radical scavenging activity and lipid peroxidation inhibiting activity of Aauricula melanin were greater than 40%.Thus, Aauricula melanin could be further used as a natural healthful food colorant.%对黑木耳天然黑色素的理化性质与抗氧化活性进行了研究,结果表明:黑木耳天然黑色素粉末呈黑色(L*=41.03),略带红色和黄色(a*=2.26,b*=3.78),具有与其他黑色素相似的溶解性;黑木耳黑色素热稳定性较强,100℃加热4h后,色素保存率仍达到88.0%,但对光照敏感,自然光照射5d时残存的黑色素仅为25.3%;黑木耳黑色素具有较强的抗氧化能力,1.0mg/mL浓度的黑色素溶液羟自由基清除率和脂质过氧化抑制率均在40%以上.黑木耳黑色素可进一步开发为具有保健功能的天然食用色素.

  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. 工程菌所产黑色素对苏云金芽孢杆菌毒力的保护作用%Protection of Bacillus thuringiensis toxicity by melanin from engineering bacteria

    Institute of Scientific and Technical Information of China (English)

    胡海艳; 黄雅莉; 梁志洲; 周世宁

    2011-01-01

    对基因工程菌Escherichia.Coli fss6所产黑色素进行了紫外保护研究.结果表明:添加黑色素的苏云金芽孢杆菌(Bt)经紫外照射后菌体的存活率是不加黑色素菌体的8倍;黑色素能有效保护Bt的晶体毒素蛋白免受紫外照射的降解;随着被照射菌体中黑色素浓度的增加,其杀虫活性也相应提高.%The protection of the ability of Bacillus thuringiensis against ultraviolet irradiation by melanin produced by engineering bacterium Escherichia coli fss6 was studied.Results showed that the survival ratio of the B.thuringiensis under the protection of melanin was 8 times higher than that of those without melanin after UV irradiation.Melanin could protect the toxin protein from UV degradation significantly, the insecticidal activity of B.thuringiensis was improved as the concentration of melanin increased.

  14. 美白剂的发展现状及其黑色素抑制机理的研究进展%Adcance in Studies of Melanins Inhibting Mechanism and Development of Skin Lightenors

    Institute of Scientific and Technical Information of China (English)

    贾爱群; 孙洋; 王建新

    2001-01-01

    For exploiting and applying of melanins inhibitors in skin lightening cosmetic fiel&, the development state of melanins inhibitors during of recent years is reviewed in this article. Then, on the basis of reseach into the melanins formation mechanism.melanins inhibiting mechanism is overviewed in the lay of subcellars, too. In the end, the developments direction of melanins inhibitors in the cosmetic fields are brought forwars%鉴于黑色素抑制剂在美白型化妆品中的不断开发、应用,使得对近年来的黑色素抑制剂的发展状况作一综述显得尤为必要;在黑色素形成机理研究的基础上,从亚细胞结构层次上对黑色素的抑制机理作一综述;最后,为黑色素抑制剂在化妆品等领域的研究、开发提出未来发展思路。

  15. DeoxyArbutin and its derivatives inhibit tyrosinase activity and melanin synthesis without inducing reactive oxygen species or apoptosis.

    Science.gov (United States)

    Chawla, Smita; Kvalnes, Kalla; deLong, Mitchell A; Wickett, Randall; Manga, Prashiela; Boissy, Raymond E

    2012-10-01

    Safety is a major concern in developing commercial skin-lightening agents. Here, we report the modulating effects of deoxyArbutin (dA) and its second-generation derivatives - deoxyFuran (dF), 2-fluorodeoxyArbutin (fdA), and thiodeoxyArbutin (tdA) - on tyrosinase, and consequently, on melanization. Results demonstrate that dA and its derivatives inhibit tyrosine hydroxylase and dopa oxidase activity of tyrosinase. The inhibition is dose-dependent, thereby inhibiting melanin synthesis in intact melanocytes, when used at concentrations that retain 95% viability of the treated cells in culture. Herein we demonstrate that dA, and its second-generation derivatives dF, fdA, and tdA, exhibit dose-dependent reductions in melanocyte cell number, primarily due to inhibition of proliferation rather than initiation of apoptosis as exemplified by hydroquinone (HQ), ie, cytostatic as opposed to cytotoxic. Human and murine melanocytes with functional mutations in either tyrosinase or tyrosinase-related protein 1 (Tyrp1) are less sensitive to the cytostatic effects of dA and its derivatives. Minimal amounts of reactive oxygen species (ROS) were generated upon treatment with dA and its derivatives, in contrast to a dramatic amount of ROS induced by HQ. This increase in ROS subsequently induced the expression of the endogenous antioxidant catalase in treated melanocytes. Treatment with exogenous antioxidants provided protection for melanocytes treated with HQ, but not dA and its derivatives, suggesting that HQ exerts more oxidative stress. These studies demonstrate that dA and its derivatives are relatively safe tyrosinase inhibitors for skin lightening or for ameliorating hyperpigmented lesions.

  16. Melanin concentrating hormone (MCH) is involved in the regulation of growth hormone in Cichlasoma dimerus (Cichlidae, Teleostei).

    Science.gov (United States)

    Pérez Sirkin, D I; Cánepa, M M; Fossati, M; Fernandino, J I; Delgadin, T; Canosa, L F; Somoza, G M; Vissio, P G

    2012-03-01

    Growth hormone (GH) is the main pituitary hormone involved in somatic growth. In fish, the neuroendocrine control of GH is multifactorial due to the interaction of multiple inhibitors and stimulators. Melanin-concentrating hormone (MCH) is a cyclic peptide involved in skin color regulation of fish. In addition, MCH has been related to the regulation of food intake in both mammals and fish. There is only one report presenting evidences on the GH release stimulation by MCH in mammals in experiments in vitro, but there are no data on non-mammals. In the present work, we report for the first time the sequence of MCH and GH cDNA in Cichlasoma dimerus, a freshwater South American cichlid fish. We detected contacts between MCH fibers and GH cells in the proximal pars distalis region of the pituitary gland by double label confocal immunofluorescence indicating a possible functional relationship. Besides, we found that MCH increased GH transcript levels and stimulated GH release in pituitary cultures. Additionally, C. dimerus exposed to a white background had a greater number of MCH neurons with a larger nuclear area and higher levels of MCH transcript than those fish exposed to a black background. Furthermore, fish reared for 3 months in a white background showed a greater body weight and total length compared to those from black background suggesting that MCH might be related to somatic growth in C. dimerus. Our results report for the first time, that MCH is involved in the regulation of the synthesis and release of GH in vitro in C. dimerus, and probably in the fish growth rate.

  17. 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

    Study Objectives 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. Methods 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. Results 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. Conclusions 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. PMID:28061506

  18. Identification of PaPKS1, a polyketide synthase involved in melanin formation and its use as a genetic tool in Podospora anserina.

    Science.gov (United States)

    Coppin, Evelyne; Silar, Philippe

    2007-08-01

    In the filamentous fungus Podospora anserina, many pigmentation mutations map to the median region of the complex locus '14', called segment '29'. The data presented in this paper show that segment 29 corresponds to a gene encoding a polyketide synthase, designated PaPKS1, and identifies two mutations that completely or partially abolish the activity of the PaPKS1 polypeptide. We present evidence that the P. anserina green pigment is a (DHN)-melanin. Using the powerful genetic system of PaPKS1 cloning, we demonstrate that in P. anserina trans-duplicated sequences are subject to the RIP process as previously demonstrated for the cis-duplicated regions.

  19. Research progress in the treatment of gingival melanin pigmentation%牙龈黑色素沉着治疗研究进展

    Institute of Scientific and Technical Information of China (English)

    夏静

    2014-01-01

    牙龈黑色素沉着(gingival melanin pigmentation,GMP)是由于黑色素母细胞分泌的黑色素颗粒沉积在牙龈黏膜的基底层及固有层所导致.虽然在多数情况下它不是病理性症状,但却给许多患者,尤其是露龈笑的患者造成美观上的困扰.本文对GMP的治疗方法及研究进展做一综述.

  20. Pilot study to visualise and measure skin tissue oxygenation, erythema, total haemoglobin and melanin content using index maps in healthy controls

    Science.gov (United States)

    Poxon, Ian; Wilkinson, Jack; Herrick, Ariane; Dickinson, Mark; Murray, Andrea

    2014-02-01

    We report on a method for analysing multispectral images of skin in vivo for the measurement and visualisation of skin characteristics. Four different indices were used to characterise skin tissue oxygenation, erythema, total haemoglobin and melanin content. Index values were calculated pixel-wise and combined to create index maps to visualise skin properties. Quantitative measurement of tissue oxygenation saturation was possible by calibrating the oxygenation index using a commercial, calibrated oximeter. Index maps were tested by arterial occlusion of the index finger with multispectral images taken before, during and after occlusion in a pilot study with 10 healthy controls.

  1. 采用空穴阻挡层提高有机太阳电池效率的研究%Adsorption Influencing Factors and Isotherms of Squid Melanin on Pb^2+ and Cr^6+

    Institute of Scientific and Technical Information of China (English)

    鲁婷婷; 林琳; 褚梦思; 汪盼盼; 黄乾; 宋茹

    2012-01-01

    为研究BCP对有机太阳电池的影响,制备了含BCP层的体相异质结电池,器件结构为:ITO/PEDOT:PSS/P3HT+PCBM/BCP/LiF/Al。结果表明:BCP层起到了空穴阻挡和电子传输的作用,器件性能随着BCP层厚度的不同而变化,当BCP厚度为6nm时,其性能最好。%In this study, squid melanin was used as adsorbent to remove of Pb^2+ and Cr^6+ from aqueous solutions, the adsorption factors including squid melanin content, adsorption time, adsorption temperature and solution pH were investigated, as well as the adsorption isotherms were analyzed. Results showed that the added squid melanin effectively adsorbed Pb^2+ and Cr^6+ in aqueous solutions. The removal rates of Pb^2+ and Cr^6+ were above 85.00% after adsorption of 15 min by squid melain. In addition, the removal rate of Pb^2+ decreased with the increased adsorption temperatures, whereas, the maximum adsorption of Cr^6+ was found at 35℃. The low adsorption capacity of squid melanin on Pb^2+ was observed at solution pH of 5.0, and the effective solution pH for Cr^6+ removal was in the range of 4.0 to 6.0. Furthermore, results of adsorption isotherms revealed that the adsorption characteristic of squid melanin on Cr^6+ fitted well to Langmuir and Freundlich models. By comparison, the adsorption behavior of squid melanin on Pb^2+ only had a good correlation with the Langmuir isotherm.

  2. Experimental Studies of Melanin Associated Antigen and Its Relationship with Sympathetic Ophthalmia and Vogt-Kayanagi-Harada Syndrome

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng Lin; Shaozhen Li; Chufeng Xie; Xiangkun Huang; Zhigang Fan

    2003-01-01

    Purpose: To discuss the relationship of Bovine Melanin-Associated Antigen (BMAA) to Sympathetic Ophthalmia (SO) and Vogt-Kayanagi-Harada (VKH) syndrome.Methods:BMAA was isolated and purified from bovine iris and ciliary body and MTT method was used to measure the peripheral lymphocyte reactions of SO and VKH syndrome patients to BMAA. 15 cases of SO were included in the SO group with 11 males and 4 females. The average age was 37.5, ranging from 23 to 56 years; 15 patients with VKH syndrome were included in the VHK group with 7 males and 8 females. Their average age was 37.2 years, ranging from 24 to 69 years; 20 normal individuals without ocular and systemic autoimmune diseases were included in the control group.These included 9 males and 11 females, aging from 14 to 28 with an average of 23.8 years.Results: The OD values of each group were as follows: SO controls 0.327+0.032; SO+ BMAA 0.490+0.758; SO+PHA 0.5310+0.918; VKH controls 0.328+0.503; VKH+BMAA 0.430 +0.530; VKH +PHA 0.328 +0.484;Normal controls 0.304 +0.267; Normal +BMAA 0.343+0.326; Normal+PHA 0.477+0.598. The average OD values of peripheral lymphocytes to BMAA stimulation in SO patients and normal controls were 0.490 and 0.343 respectively. The difference was statistically significant, P< 0.001; The average OD values of peripheral lymphocytes to BMAA stimulation in SO and VKH syndrome patients were 0.470 and 0.430 respectively. The difference was not statistically significant,P > 0.05.Conclusions:BMAA effectively stimulate the proliferative reaction of peripheral lymphocytes in SO patients and BMAA may act as an antigen and contribute in the pathological process of SO.No difference in proliferative reaction of peripheral lymphocytes was found between SO and VKH syndrome patients after BMAA stimulations and BMAA may be involved in the development of both SO and VKH yndrome.

  3. 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.

  4. 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

  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. 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 the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of YWA1, a precursor of fungal DHN melanin. Our results show that the A. niger alb1 PKS is responsible for the production of the polyketide precursor for DHN melanin biosynthesis. Deletion of alb1 elimnates the production of major metabolites, naphtho-γ-pyrones. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.

  7. 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

  8. 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.

  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. 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.

  11. 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.

  12. Determination and Characterization of Extracellular Melanin from Setosphaeria turcica and Influencing Factors of Its Production%玉米大斑病菌的胞外黑色素种类及影响其产量的因素

    Institute of Scientific and Technical Information of China (English)

    吴楠; 李青为; 曹志艳; 张娇; 郝志敏; 董金皋

    2013-01-01

    [目的]对玉米大斑病菌胞外黑色素的种类进行确定,探索影响玉米大斑病菌野生型菌株胞外黑色素产量的因素.[方法]利用酸碱沉淀法提取玉米大斑病菌01-23(野生型)菌株和1,3,8-三羟基萘还原酶(3HNR)基因缺失突变菌株△St3hnr-3的胞外黑色素,采用红外光谱分析确定黑色素的种类.通过在培养基中添加不同的物质,确定影响胞外黑色素产量的因素.[结果]玉米大斑病菌胞外黑色素不同于DHN黑色素,2种黑色素的理化性质相似,溶解于热碱溶液,且与FeCl3反应产生沉淀.在振荡培养条件下,加入酪氨酸和三环唑分别使胞外黑色素的产量提高了2倍和1.5倍,而Cu2+浓度低于0.5μmol·L-1利于胞外黑色素的合成,反之则表现抑制作用;pH值为6时较利于对胞外黑色素分泌.[结论]玉米大斑病菌胞外黑色素为DOPA黑色素类型,酪氨酸和三环唑对胞外黑色素的产生具有明显促进作用.%[Objective] The objective of this study is to determine the type of extracellular melanin from Setosphaeria turcica and explore the influencing factors of its production to lay a foundation for further clarification of the relationship between melanin and pathogenicity.[Method] Acid precipitation method was used to extract the extracellular melanin of 01-23 and △St3hnr-3 strain.The type of melanin was preliminarily identified with infrared spectroscopy.Media containing tyrosine,tricyclazole,Cu2+ and different pH values were used to determine the influences of these factors on the production of extracellular melanin.[Result] The infrared spectroscopy of extracellular melanin in S.turcica was different from the DHN melanin,while the physical and chemical properties of the samples from both strains were similar.It could dissolve in hot alkaline solution and produce precipitation when it was reacted with FeCl3.Under the shaking culture,the contents of extracellular melanin in the culture filtrates

  13. Effects of hesperidin on the melanin synthesis and tyrosinase activity of human primary melanocytes%橙皮苷对人黑素细胞黑素合成和酪氨酸酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    岳学状; 王大光; 马慧军; 朱文元

    2011-01-01

    目的:观察橙皮苷对人原代黑素细胞酪氨酸酶及黑素合成的影响,探讨其作用机制.方法:选择50、100、200、300、400、500 和600 mg/L 7 个浓度的橙皮苷作用于体外培养的人表皮黑素细胞72 h,分别测定细胞增殖活性、酪氨酸酶活性及黑素含量.结果:橙皮苷显著抑制黑素合成和酪氨酸酶活性,且呈浓度依赖性.结论:橙皮苷可抑制黑素合成和酪氨酸酶活性.%Objective: To observe the effects of hesperidin on melanin synthesis and tyrosinase activity. Methods: Normal human melanocytes were isolated from human foreskin. Melanocytes were incubated with the following concentrtions of hesperidin: 50, 100, 200, 300, 400、 500 and 600mg/L for 72 h, respectively .The rate of proliferation, melanin content, and tyrosinase activity were measured. Results: The results showed that hesperidin treatment inhibited melanin synthesis and tyrosinase activity significantly compared with the control. Hesperidin decreased the cellular melanin content in dose dependent manner. Conclusion: Hesperidin can inhibit melanogenesis and the activity of tyrosinase, which may be induced by down regulation of tyrosinase.

  14. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion; Estudo clinico comparativo entre as tecnicas de despigmentacao melanica gengival: laser neodimio (1064 nm) e gengivoabrasao

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Luis Mario de Melo

    2002-07-01

    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)

  15. Study on the scavenging DPPH free radical activity of melanin in crude product of Chinese sweet gum leaves%枫香树叶黑色素粗产品清除DPPH自由基活性研究

    Institute of Scientific and Technical Information of China (English)

    谢宇奇; 莫春凤; 奚文权

    2016-01-01

    The ability of melanin in Chinese sweet gum leaves for scavenging DPPH free radical activity was discussed in order to utilize the resource of Chinese sweet gum leaves. The melanin was extracted by immersion extraction;the crude product of melanin in the leaves was purified with AB - 8 macroporous resin. The antioxidant ability of the melanin in the leaves,ascorbic acid (Vc),pyrogallic acid,tert -butyl hydroquinone (TBHQ)and 2,6 Di tert - butyl and other substances was evaluated. The results showed that IC50 value of the melanin crude product prepared by the method was 3. 41,the order of scav-enging DPPH free radical ability of unit mass of antioxidant was pyrogallic acid > TBHQ > ascorbic acid >Chinese sweet gum leaves melanin crude product > BHT. Chinese sweet gum leaves melanin has a certain ability of scavenging DPPH free radical activity,which,as a natural pigment,has broad application pros-pect in the field of food,medicine,cosmetics and so on.%为开发利用枫香树叶资源,探讨枫香树叶黑色素清除DPPH 自由基活性的能力,浸渍提取黑色素,经AB -8大孔树脂初步纯化后得到枫香树叶黑色素粗产品。通过DPPH清除率曲线和计算IC50,评价枫香树叶黑色素、抗坏血酸、焦性没食子酸、叔丁基对苯二酚(TBHQ)、2,6-二叔丁基对甲酚等物质的抗氧化能力。结果表明:通过该方法制取的枫香树叶黑色素粗产品的IC 50值为3.41,单位质量抗氧化剂清除DPPH自由基能力次序为焦性没食子酸> TBHQ >抗坏血酸>枫香树叶黑色素粗产品> BHT。枫香树叶黑色素具有一定的清除DPPH自由基活性,作为天然色素,其在食品、药品、化妆品等领域的应用前景广阔。

  16. Extraction, Purification and Antioxidant Activity of Melanin from the Black Ants%蚂蚁黑色素的提取、纯化及抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    陶浚; 乔李娜; 童晶晶; 李杨悦; 聂少平; 胡晓波

    2012-01-01

    The melanin derived from the black ants was isolated and purified by acid hydrolysis,alkaline extraction,acid deposition and organic solvents abstersion. The solubility showed that the melanin was soluble in alkaline solution,but insoluble in water,acid solution and organic solvent. It may be a type of indoles melanin from the UV-visible spectrogram and the infrared spectrogram. The total antioxidant capacity,hydroxyl radical scavenging capacity and reducing power of the melanin were measured by the spectrophotometric method. The results showed that the melanin had certain antioxidant activity, but lower than that of the vitamin C.%对黑蚂蚁采用盐酸水解、氢氧化钠溶液提取、盐酸沉淀,以及多种有机溶剂洗涤等工艺手段提取分离、纯化得到黑蚂蚁黑色素.研究发现黑蚂蚁黑色素溶于碱性溶液,不溶于水、酸及有机溶剂;其紫外吸收光谱与红外光谱具有吲哚型黑色素典型光谱性质.利用分光光度法测定了黑蚂蚁黑色素的总抗氧化能力、羟基自由基清除能力及还原力,试验结果表明:黑蚂蚁黑色素有一定的抗氧化能力,但在试验范围内其抗氧化能力比维生素C低.

  17. 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 H;

    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......1 gene and schizophrenia, based on analyses of a larger sample and an increased number of single nucleotide polymorphisms (SNPs) than used in the previous study. METHODS: Eighteen SNPs in the MCHR1 gene region were genotyped in a Caucasian case-control sample from Denmark consisting of 390......, predominantly seen in men where one SNP (rs133073) remained significant (P=0.003) after correction for multiple testing. When combining the P values in the proximal region of MCHR1, the region-wise P value was low (P=0.009) supporting that variations in this part of the gene is associated with schizophrenia...

  18. Inhibitory effect of 2,4,2',4'-tetrahydroxy-3-(3-methyl-2-butenyl)-chalcone on tyrosinase activity and melanin biosynthesis.

    Science.gov (United States)

    Zhang, Xiaodong; Hu, Xiao; Hou, Aijun; Wang, Heyao

    2009-01-01

    2,4,2',4'-Tetrahydroxy-3-(3-methyl-2-butenyl)-chalcone (TMBC), a naturally occurring compound from Morus nigra, modulated melanogenesis by inhibiting tyrosinase. TMBC inhibited the L-dopa oxidase activity of mushroom tyrosinase with an IC(50) value of 0.95+/-0.04 microM, which was more potent than kojic acid (IC(50)=24.88+/-1.13 microM), a well-known tyrosinase inhibitor. The kinetic studies of tyrosinase inhibition revealed that TMBC acts as a competitive inhibitor of mushroom tyrosinase with L-dopa as the substrate. Furthermore, TMBC effectively inhibited both cellular tyrosinase activity and melanin biosynthesis in B16 melanoma cells without significant cytotoxicity. The inhibitory effect of TMBC on melanogenesis was attributed to the direct inhibition of tyrosinase activity, rather than the suppression of tyrosinase gene expression. These results indicated that TMBC may be a new promising pigmentation-altering agent for cosmetic or therapeutic applications.

  19. Viability of brown trout embryos positively linked to melanin-based but negatively to carotenoid-based colours of their fathers.

    Science.gov (United States)

    Wedekind, Claus; Jacob, Alain; Evanno, Guillaume; Nusslé, Sébastien; Müller, Rudolf

    2008-08-07

    'Good-genes' models of sexual selection predict significant additive genetic variation for fitness-correlated traits within populations to be revealed by phenotypic traits. To test this prediction, we sampled brown trout (Salmo trutta) from their natural spawning place, analysed their carotenoid-based red and melanin-based dark skin colours and tested whether these colours can be used to predict offspring viability. We produced half-sib families by in vitro fertilization, reared the resulting embryos under standardized conditions, released the hatchlings into a streamlet and identified the surviving juveniles 20 months later with microsatellite markers. Embryo viability was revealed by the sires' dark pigmentation: darker males sired more viable offspring. However, the sires' red coloration correlated negatively with embryo survival. Our study demonstrates that genetic variation for fitness-correlated traits is revealed by male colour traits in our study population, but contrary to predictions from other studies, intense red colours do not signal good genes.

  20. A guide to the field of palaeo colour: Melanin and other pigments can fossilise: Reconstructing colour patterns from ancient organisms can give new insights to ecology and behaviour.

    Science.gov (United States)

    Vinther, Jakob

    2015-06-01

    Melanin, and other pigments have recently been shown to preserve over geologic time scales, and are found in several different organisms. This opens up the possibility of inferring colours and colour patterns ranging from invertebrates to feathered dinosaurs and mammals. An emerging discipline is palaeo colour: colour plays an important role in display and camouflage as well as in integumental strengthening and protection, which makes possible the hitherto difficult task of doing inferences about past ecologies, behaviours, and organismal appearance. Several studies and techniques have been presented in the last couple of years that have described ways to characterize pigment patterns. Here, I will review the available methods and the likely applications to understand past ecologies. A golden age of colourized dinosaurs and other animals is now dawning upon us, which may elucidate the nature of ancient predator prey interactions and display structures. © 2015 WILEY Periodicals, Inc.

  1. 黄褐斑:表皮屏障与黑素屏障失衡%Melasma: the imbalance between epidermal barrier and melanin barrier

    Institute of Scientific and Technical Information of China (English)

    宋秀祖; 许爱娥

    2012-01-01

    黄褐斑是一种面部获得性色素增加性皮肤病,发病机制尚不清,概述黄褐斑的表皮屏障及黑素屏障的变化,以及真皮血管的变化.在此基础上推测黄褐斑的可能发病机制为紫外线、化妆品、避孕药等不良刺激导致表皮屏障功能障碍,代偿性引起黑素细胞功能活跃,黑素屏障增强,形成临床上表现为色素沉着为主的皮肤病.进一步导致真皮毛细血管扩张,血管内皮生长因子表达增加,促进色素沉着发生.%Melasma is an acquired skin disease characterized by facial hyperpigmentation of unclear pathogenesis.This paper describes the changes of epidermal barrier,melanin barrier and dermal blood vessels in melasma.On this basis,the pathogenesis of melasma is speculated to be associated with ultraviolet,cosmetics,contraceptives and other adverse stimuli,which cause epidermal barrier dysfunction,lead to a compensatory increase in melanocyte activity and melanin barrier followed by the occurrence of diseases characterized by skin pigmentation.Moreover,dermal telangiectasis is induced and vascular endothelial growth factor expression is enhanced,which accelerate skin pigmentation accordingly.

  2. Stability of polydopamine and poly(DOPA) melanin-like films on the surface of polymer membranes under strongly acidic and alkaline conditions.

    Science.gov (United States)

    Wei, Houliang; Ren, Jun; Han, Bo; Xu, Li; Han, Lulu; Jia, Lingyun

    2013-10-01

    This study investigated the stability of polydopamine and poly(3,4-dihydroxyphenylalanine) (poly(DOPA)) melanin-like films on the surface of polymer substrates. Three polymer membranes, polypropylene (PP), poly(vinylidenefluoride) (PVDF) and nylon, were modified with polydopamine or poly(DOPA), and then immersed in 0.1M HCl or NaOH, followed by UV-vis spectrometry analysis to detect the presence of film detachment. The results showed that the outer parts of both polydopamine and poly(DOPA) films were detached, probably due to electrostatic repulsion between the polymers within the film, when the modified membranes were washed in HCl or NaOH solution. These two films were more stable in strongly acidic solution, but the stability of poly(DOPA) film was better than that of polydopamine film. Compared to the films on the surface of PVDF or nylon membrane, films on PP surface showed the lowest stability, possibly because of the hydrophobic property of PP. The process of film detachment was analyzed by GPC, which showed that unreacted dopamine or DOPA monomers were still present in the freshly formed films. The unreacted monomers, as well as polydopamine or poly(DOPA) that were incorporated in the film via noncovalent interactions, became detached when the film was exposed to strongly acidic or alkaline solution. Oxidation of freshly formed films could significantly enhance their stability. The results therefore provide us with a better understanding of the stability of melanin-like films, and allow us to develop an effective strategy for constructing stable films.

  3. Effect of apigenin-7-glucoside, genkwanin and naringenin on tyrosinase activity and melanin synthesis in B16F10 melanoma cells.

    Science.gov (United States)

    Nasr Bouzaiene, Nouha; Chaabane, Fadwa; Sassi, Aicha; Chekir-Ghedira, Leila; Ghedira, Kamel

    2016-01-01

    In this study, we have investigated the effects of apigenin-7-glucoside, genkwanin and naringenin, on mouse melanoma B16F10 cell proliferation. Influence of these natural products on percentage cell distribution in cycle phases and melanogenesis was also studied. Cell viability was determined at various periods using the MTT assay, whereas effects of tested compounds on progression through the cell cycle were analyzed by flow cytometry. In addition, amounts of melanin and tyrosinase were measured spectrophotometrically at 475 nm. Besides, the mechanism involved on the death route induced by the tested molecules was evaluated using the bis-benzimide trihydrochloride coloration method (Hoechst 33258). Apigenin-7-glucoside, genkwanin and naringenin exhibited significant anti-proliferative activity against B16F10 melanoma cells after 24 and 48 h of incubation. Furthermore, apigenin-7-glucoside, genkwanin and naringenin provoked an increase of subG0/G1, S and G2/M phase cell proportion with a significant decrease of cell proportion in G0/G1 phases. The results evaluated using Hoechst 33,258, confirm that the percentage of B16F10 cells observed in the sub G0/G1 phase were undergoing apoptosis. Moreover, apigenin-7-glucoside and naringenin revealed an ability to enhance melanogenesis synthesis and tyrosinase activity of B16F10 melanoma cells. Whereas genkwanin induces a decrease of melanin synthesis by inhibiting tyrosinase activity. Our results promote the introduction of genkwanin in cosmetic preparations, as skin whitening agent, whereas apigenin-7-glucoside and naringenin should be introduced into cosmetic products as natural tanning agents. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Characterization of melanin-concentrating hormone (MCH) and its receptor in chickens: Tissue expression, functional analysis, and fasting-induced up-regulation of hypothalamic MCH expression.

    Science.gov (United States)

    Cui, Lin; Lv, Can; Zhang, Jiannan; Mo, Chunheng; Lin, Dongliang; Li, Juan; Wang, Yajun

    2017-06-05

    Melanin-concentrating hormone (MCH) is a neuropeptide expressed in the brain and exerts its actions through interaction with the two known G protein-coupled receptors, namely melanin-concentrating hormone receptor 1 and 2 (MCHR1 and MCHR2) in mammals. However, the information regarding the expression and functionality of MCH and MCHR(s) remains largely unknown in birds. In this study, using RT-PCR and RACE PCR, we amplified and cloned a MCHR1-like receptor, which is named cMCHR4 according to its evolutionary origin, and a MCHR2 from chicken brain. The cloned cMCHR4 was predicted to encode a receptor of 367 amino acids, which shares high amino acid identities with MCHR4 of ducks (90%), western painted turtles (85%), and coelacanths (77%), and a comparatively low identity to human MCHR1 (58%) and MCHR2 (38%), whereas chicken MCHR2 encodes a putative C-terminally truncated receptor and is likely a pseudogene. Using cell-based luciferase reporter assays or Western blot, we further demonstrated that chicken (and duck) MCHR4 could be potently activated by chicken MCH1-19, and its activation can elevate calcium concentration and activate MAPK/ERK and cAMP/PKA signaling pathways, indicating an important role of MCHR4 in mediating MCH actions in birds. Quantitative real-time PCR revealed that both cMCH and cMCHR4 mRNA are expressed in various brain regions including the hypothalamus, and cMCH expression in the hypothalamus of 3-week-old chicks could be induced by 36-h fasting, indicating that cMCH expression is correlated with energy balance. Taken together, characterization of chicken MCH and MCHR4 will aid to uncover the conserved roles of MCH across vertebrates. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Peripheral injections of melanin-concentrating hormone receptor 1 antagonist S38151 decrease food intake and body weight in rodent obesity models

    Directory of Open Access Journals (Sweden)

    Odile eDella-Zuana

    2012-12-01

    Full Text Available The compound S38151 is a nanomolar antagonist that acts at the melanin-concentrating hormone receptor 1 (MCH1. S38151 is more stable than its purely peptide counterpart, essentially because of the blockade of its N-terminus. Therefore, , its action on various models of obesity was studied. Acute intracerebroventricular (i.c.v. administration of S38151 in wild-type rats counteracted the effect of the stable precursor of melanin-concentrating hormone (MCH, NEI-MCH, in a dose-dependent manner (from 0.5 to 50 nmol/kg. In genetically obese Zucker fa/fa rats, daily i.c.v. administration of S38151 induced dose-dependent (5, 10, and 20 nmol/kg inhibition of food intake, water intake, and body weight gain, as well as increased motility (maximal effect observed at 20 nmol/kg. In Zucker fa/fa rats, intraperitoneal injection of S38151 (30 mg/kg induced complete inhibition of food consumption within 1 h. Daily intraperitoneal injection of S38151 (10 and 30 mg/kg into genetically obese ob/ob mice or diet-induced obese mice is able to limit body weight gain. Furthermore, S38151 administration (10 and 30 mg/kg does not affect food intake, water intake, or body weight gain in MCHR1-deleted mice, demonstrating that its effects are linked to its interaction with MCH1. These results validate MCH1 as a target of interest in obesity. S38151 cannot progress to the clinical phase because it is still too poorly stable in vivo.

  6. Hypothalamic kappa opioid receptor mediates both diet‐induced and melanin concentrating hormone–induced liver damage through inflammation and endoplasmic reticulum stress

    Science.gov (United States)

    Imbernon, Monica; Sanchez‐Rebordelo, Estrella; Romero‐Picó, Amparo; Kalló, Imre; Chee, Melissa J.; Porteiro, Begoña; Al‐Massadi, Omar; Contreras, Cristina; Fernø, Johan; Senra, Ana; Gallego, Rosalia; Folgueira, Cintia; Seoane, Luisa M.; van Gestel, Margriet; Adan, Roger A.; Liposits, Zsolt; Dieguez, Carlos; López, Miguel

    2016-01-01

    The opioid system is widely known to modulate the brain reward system and thus affect the behavior of humans and other animals, including feeding. We hypothesized that the hypothalamic opioid system might also control energy metabolism in peripheral tissues. Mice lacking the kappa opioid receptor (κOR) and adenoviral vectors overexpressing or silencing κOR were stereotaxically delivered in the lateral hypothalamic area (LHA) of rats. Vagal denervation was performed to assess its effect on liver metabolism. Endoplasmic reticulum (ER) stress was inhibited by pharmacological (tauroursodeoxycholic acid) and genetic (overexpression of the chaperone glucose‐regulated protein 78 kDa) approaches. The peripheral effects on lipid metabolism were assessed by histological techniques and western blot. We show that in the LHA κOR directly controls hepatic lipid metabolism through the parasympathetic nervous system, independent of changes in food intake and body weight. κOR colocalizes with melanin concentrating hormone receptor 1 (MCH‐R1) in the LHA, and genetic disruption of κOR reduced melanin concentrating hormone–induced liver steatosis. The functional relevance of these findings was given by the fact that silencing of κOR in the LHA attenuated both methionine choline–deficient, diet‐induced and choline‐deficient, high‐fat diet–induced ER stress, inflammation, steatohepatitis, and fibrosis, whereas overexpression of κOR in this area promoted liver steatosis. Overexpression of glucose‐regulated protein 78 kDa in the liver abolished hypothalamic κOR‐induced steatosis by reducing hepatic ER stress. Conclusions: This study reveals a novel hypothalamic–parasympathetic circuit modulating hepatic function through inflammation and ER stress independent of changes in food intake or body weight; these findings might have implications for the clinical use of opioid receptor antagonists. (Hepatology 2016;64:1086‐1104) PMID:27387967

  7. 微波辅助提取黎豆种皮黑色素%Extraction of Melanin from the Seed Coat of Mucuna prurients ( L.) by Microwave-assisted Method

    Institute of Scientific and Technical Information of China (English)

    董华群; 汪跃华; 董华强; 高赛文

    2012-01-01

    [目的]研究微波辅助碱提酸析法提取黎豆黑色素的工艺条件.[方法]分别采用碱提酸析法和微波辅助碱提酸析法提取成熟黎豆种皮中的黑色素,以紫外分光光度法测定黎豆黑色素的含量.[结果]黎豆种皮黑色素含量为2.41%;碱提酸析法最佳提取工艺为1.0mol/L NaOH溶液为提取剂、料液比1:20(g/ml),浸提时间4~6h,再调提取液pH值为2,进行酸析;在此条件下,黑色素粗提物得率为(91.2±2.0)%,黑色素纯度为(36.5±2.1)%;微波辅助碱提酸析最佳工艺为料液比1:20(g/ml)、1.0 mol/L NaOH溶液为提取剂、微波高档功率处理25 min;在此条件下,黑色素粗提物得率为(95.3±1.5)%,黑色素纯度达到(37.4±1.5)%.[结论]黎豆种皮中含有较为丰富的植物黑色素,值得进一步研究和开发利用;微波辅助较常规碱提酸析工艺明显提高了黎豆种皮黑色素粗提物得率,且大大缩短了提取时间.%[Objective] To research on the extraction technology of melanin from the seed coat of Mucuna prurients (L. ) by microwave-assisted alkaline extraction and acid precipitation. [ Method] Melanin was extracted from the seed coat of M. Prurients by the method of microwave-assisted alkaline extraction-acid precipitation and the method of alkaline extraction-acid precipitation. Content of melanin in M. Prurients was detected by UV spectrophotometry. [ Result] The melanin content of the seed coat was 2.41%. The optimal conditions for alkaline extraction-acid precipitation were 1.0 mol/L NaOH solution, 1:20 (g/ml) solid-liquid ratio,4 -6 h extraction time,and pH =2 for the precipitation of melanin. Under these conditions, the extraction rate of the crude extracts of melanin was (95.3 ±1.5)%; and the purity of melanin reached (37.4 ±1.5)%. [ Conclusion ] The seed coat of M. Prurients was rich in melanin, which deserved further research and development. Microwave assistance could significantly enhance the extraction

  8. 马尔尼菲青霉酵母细胞黑素的分离纯化及理化性质的分析%Isolation, purification and physicochemical characterization of melanin from yeast cells of Penicillium marneffei

    Institute of Scientific and Technical Information of China (English)

    郭婷; 梁伶; 刘栋华; 韦立莉

    2013-01-01

    目的 探讨提取、纯化马尔尼菲青霉(PM)酵母细胞的黑素并研究其理化性质.方法 在基础液体培养基中加入左旋多巴37℃振荡培养PM酵母细胞,通过溶壁酶、变性剂和浓酸等处理PM酵母细胞以分离提取黑素,用化学分析、紫外光谱、红外光谱以及电子顺磁共振(EPR)波谱研究PM黑素的理化性质.结果 PM黑素与合成多巴黑素的理化性质相似,均溶解于碱,不溶于酸,不溶于水和大多数有机溶剂,在pH≤3时产生沉淀,能被氧化剂H2O2漂白.紫外光谱分析显示,在205 nm处有最大吸收峰,随波长的增加其吸收值减小.红外光谱分析表明,PM黑素具有经典的黑素红外吸收特征,即在3μm附近和6μm附近各有一个吸收峰;EPR提示PM黑素含有稳定的自由基.结论 PM酵母细胞能利用外源性左旋多巴合成多巴黑素.%Objective To isolate and purify melanin from yeast cells of Penicillium mameffei (PM) and to analyze its physicochemical features.Methods PM yeast cells were cultured in minimal medium containing levodopa (L-dopa) with continuous shaking at 37 ℃.Melanin was isolated from the yeast cells of PM by cell walllysing enzyme,denaturant,concentrated hot acid,and purified by sodium hydroxide and concentrated hydrochloric acid.The physicochemical properties of isolated melanin were assessed on the basis of combined chemical analysis and spectroscopic methods including ultraviolet-visible (UV-vis),Fourier transform infrared (FT-IR) and electronparamagnetic resonance (EPR).Results Similar to synthetic dopa-melanin,the isolated melanin from PM was alkali soluble,acid-resistant,insoluble in water and most organic solvents,precipitated at or below PH 3,and could be bleached by hydrogen peroxide.UV-vis spectrophotometric analysis showed that the PM-derived melanin had a typical absorption peak at 205 nm and the absorbance decreased with the increase of wavelength.FT-IR spectroscopy displayed two absorption peaks at

  9. Influence of several treatments on properties of squid melanin%几种物理处理法对鱿鱼墨黑色素理化特性的影响

    Institute of Scientific and Technical Information of China (English)

    袁丽; 高瑞昌; 郭雪霞; 马海乐

    2011-01-01

    以鱿鱼墨黑色素为原料,利用紫外可见光谱仪、红外光谱仪和扫描电子显微镜研究超高压、亚临界和超声波处理对黑色素理化特性的影响.结果表明:超高压处理对黑色素理化特征变化影响最小,而亚临界和超声波处理可以引起黑色素发生较大变化,导致黑色素发生脱氨反应并且破坏亚氨基与金属离子螯合作用,但对于黑色素的特征结构,5,6二羟基吲哚(DHI)并没有造成显著影响;超声波和亚临界处理对黑色素颗粒物理形态均有一定的破坏作用,超声波处理可使黑色素颗粒破碎生成更小的颗粒和碎片,经处理后直径100 nm的颗粒数目比例提高至25%,比原料多了24.5%,其破碎效果大于亚临界处理.超声波处理可作为黑色素可溶性活性物质萃取的有效方法.%The influences of the ultra high pressure, subcritical water and ultrasonic wave treatment on the squid melanin were investigated by ultraviolet spectrophotometer? Infrared spectrometer and scanning electron microscopy (SEM) analysis. The results showed that the change of squid melanin caused by ultra high pressure was almost ig-norable. The significant change of melanin was detected after treated by the subcritical water or the ultrasonic waves. The amidocyanogen and the chelate structure between imidogen and metal ion in melanin could be destroyed under the condition of sub-critical or ultrasonic wave treatment. However, 5 ,6-dihydroxyindole that was the characteristic structure of melanin was intact. In addition, the shape of melanin was broken by the subcritical water or ultrasonic wave treatment. The change of the melanin shape caused by ultrasonic wave treatment was more significant than that of subcritical water treatment. There were more scraps and granules appeared after the mela-nin treated by ultrasonic wave. The proportion of the granule whose diameter was lower than 100 nm was up to 25 percent. It was only 0. 5 percent in

  10. Effect of calcipotriol on melanin synthesis by human melanoeytes%卡泊三醇对黑素细胞黑素合成的影响

    Institute of Scientific and Technical Information of China (English)

    汤芦艳; 傅雯雯; 张勇; 祝绿川; 郑志忠

    2009-01-01

    目的 探讨卡泊三醇对黑素细胞黑素合成的影响及其作用的可能机制.方法 用噻唑蓝比色法(MTT法)、酶学方法及NaOH法,观察卡泊三醇对黑素细胞增殖及色素合成的作用;RT-PCR和蛋白印迹分别检测卡泊三醇对黑素细胞酪氨酸酶基因转录和蛋白表达水平的影响.结果 10~(-9)~10~(-5) mol/L浓度范围的卡泊三醇对体外培养的黑素细胞增殖的影响与空白对照组比较差异无统计意义(P>0.05).同样浓度范围下,10~(-9)、10~(-8)mol/L浓度的卡泊三醇能明显增强黑素细胞的酪氨酸酶活性和促进黑素细胞的黑素含量,与空白对照组比较,酪氨酸酶活性可分别升高137%、123%(P<0.05),黑素含量分别增加40.63%、18.75%(P<0.05).其中10~(-9) mol/L浓度的卡泊三醇增强黑素细胞的酪氨酸酶活性及促进黑素细胞的黑素含量最明显.与高浓度组、空白对照组比较,10~(-9) mol/L浓度的卡泊三醇使酪氨酸酶蛋白表达增高也最明显.较空白对照组增高270.4%(P<0.05).结论 卡泊三醇对黑素细胞增殖无影响,可增加黑素细胞酪氨酸酶蛋白表达水平,提高酪氨酸酶活性,从而促进黑素细胞的黑素合成.%Objective To investigate the effect of calcipotriol on melanin synthesis by human melanocytes and its possible action mechanism.Methods Primary melanocytes were cultured with various concentrations(10~(-5),10~(-6),10~(-7),10~(-8),10~(-9),10~(-10) mol/L)of calcipotriol for 24 or 48 hours.Subsequently,MTT assay,NaoH assay.Dopa-oxidase assay,Western blot and semiquantitative RT-PCR were used to measure the cell proliferation of,melanin synthesis by.tyrosinase activity,protein and mRNA expression levels in the melanocytes.respectively.Those untreated melanocytes served as the control.Results The calcipotriol between 10~(-9) and 10~(-5) mol/L had no significant effect on the proliferation of cultured melanocytes(P>0.05).while that of 10~(-9) and 10~(-8) mol/L increased

  11. 产胞外黑色素海洋菌的鉴定及发酵条件优化%Identification and culture condition optimization for a marine extracellular melanin producing bacterium

    Institute of Scientific and Technical Information of China (English)

    田欣欣; 王琛; 曹为; 曲凌云

    2014-01-01

    从山东近海海域沉积物的微生物筛选中获得了一株高产胞外黑色素的菌株QJNY82,通过对该菌株菌落形态特征观察、生理生化检验及16S rDNA序列测定,初步确定该菌株为发光杆菌属细菌.通过对菌株QJNY82的胞外产物进行红外光谱分析,得到该细菌的胞外产物为黑色素,纯化后的黑色素的红外光谱图与标准黑色素(SIGMA)的红外光谱图一致,且该细菌所产黑色素的理化性质与标准黑色素具有一致性.该海洋菌株具有产黑色素速度快,产量高且不需要L-酪氨酸诱导的特点,而且经L-酪氨酸诱导后,可显著提高菌株QJNY82胞外黑色素的产量,在L-酪氨酸的含量为0.75 g/dm3、盐度为30、pH值为8.0、温度为28℃的条件下,菌株黑色素产量是未加L-酪氨酸的3.5倍,其产量达1.325 g/dm3.鉴于菌株QJNY82具有产黑色素的特性,将成为发光杆菌属的一个新的菌种资源.%One bacterial strain(QJNY82)that can produce melanin was isolated from a sample from Shandong coast-al sediment by our laboratory.Strain QJNY82 was identified as Photobacterium sp.based on morphological,physio-logical and biochemical tests as well as the 16S rDNA sequence analysis.We confirm the extracellular products of melanin through the infrared spectrum.The FT-IR spectra of its pigment is similar to that of the standard melanin (SIGMA).Moreover the physicochemical properties of melanin are similar to that of the standard melanin.Strain QJNY82 has advantages that it can produce melanin with a high yield in the absense of L-tyrosine.Induced by L-tyrosine,the melanin production could increases sharply.The results showed that the optimum condition was as fol-lows,i.e.L-tyrosine 0.75 g/dm3 ,pH=8.0,salinity 30,temperature 28℃.Its production reached 1.325 g/dm3 in the optimum condition.Strain QJNY82 may be identified as Photobacterium sp.,a new strain for melanin producing bacterium.

  12. EXTRACTION TECHNOLOGY OF THE MELANIN FROM AUREOBASIDIUM PULLULANS USING RESPONSE SURFACE METHOD%响应面法对出芽短梗霉黑色素提取工艺的研究

    Institute of Scientific and Technical Information of China (English)

    汪建明; 赵博; 乔长晟

    2013-01-01

    The extraction of melanin from Aureobasidium pullulans fermented liquid was studied in this paper. On the basis of single factor experiments, the main factors that influence the valeur of melanin were determined by two-level experiment, and then the optimum conditions for the extraction of the melanin from A. pullulans fermented liquid were obtained through a three-variable, three-level Box-Benhnken center-united experiment design and response surface methodology. The results showed that the optimum conditions were as follows:acid sinking time 90 min, ethanol add volume 93.17%and ethanol concentration90.42%. Under such conditions, the maximal valeur of melanin was up to 44.8μ/mL.%本研究以出芽短梗霉发酵液为原料提取黑色素,在单因素实验基础上选取实验因素与水平,用二水平实验确定影响黑色素色价的主要因素,然后根据Box-Behnken中心组合实验设计原理采用三因素三水平的响应面分析法,得到最佳提取工艺为:酸沉时间90 min、乙醇添加量93.17%、乙醇浓度90.42%。在此条件下提取黑色素色价可达44.8μ/mL。

  13. Bifunctional effects of O-methylated flavones from Scutellaria baicalensis Georgi on melanocytes: Inhibition of melanin production and intracellular melanosome transport

    Science.gov (United States)

    Tsuji-Naito, Kentaro

    2017-01-01

    The growing interest in skin lightening has recently renewed attention on the esthetic applications of Chinese herbal medicine. Although Scutellaria baicalensis Georgi is used for antipyretic and antiinflammatory purposes, its whitening effect remains unclear. This study reports three major findings: (1) S. baicalensis has a potent inhibitory effect on melanogenesis; (2) wogonin and its glycoside are the active components of S. baicalensis; and (3) O-methylated flavones from S. baicalensis, such as wogonin, inhibit intracellular melanosome transport. Using a melanin quantification assay, we showed that S. baicalensis potently inhibits melanogenesis in B16F10 cells. Componential analyses revealed that the main components of S. baicalensis are baicalin, wogonoside, baicalein, wogonin, and oroxylin A. Among these five flavones, wogonin and wogonoside consistently inhibited melanogenesis in both B16F10 melanoma cells and primary melanocytes. Wogonin exhibited the strongest inhibition of melanin production and markedly lightened the color of skin equivalents. We identified microphthalmia-associated transcription factor and tyrosinase-related proteins as potential targets of wogonin- and wogonoside-induced melanogenesis suppression. In culture, we found that the melanosomes in wogonin-treated B16F10 cells were localized to the perinuclear region. Immunoblotting analyses revealed that wogonin significantly reduced in melanophilin protein, which is required for actin-based melanosome transport. Other actin-based melanosome transport-related molecules, i.e., Rab27A and myosin Va, were not affected by wogonin. Cotreatment with MG132 blocked the wogonin-induced decrease in melanophilin, suggesting that wogonin promotes the proteolytic degradation of melanophilin via the calpain/proteasomal pathway. We determined that the structural specificities of the mono-O-methyl group in the flavone A-ring and the aglycone form were responsible for reducing melanosome transport

  14. Isolation and Identification of One Melanin-Producing Microorganism in Soil%土壤中一株产黑色素微生物的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    阎春兰; 代金刚; 王恒涛; 邱裕尧; 王茜

    2014-01-01

    One melanin-producing microorganism D-1 was isolated and purified from a soil . Based on morphological characteristics and the phylogenetical analysis of 16S rDNA sequence, this microorganism was determined to belong to Streptomyces.The growth curve , antibiotic resistance and absorption spectrum of melanin produced by D-1 were also examined and may provide the basis for subsequent optimization the melanin producing procedures .%以土壤为材料,分离纯化得到了一株产黑色素的微生物(D-1),根据菌株的形态特征并结合16S rDNA序列比对分析,确定这株产黑色素的微生物属于链霉菌属(Streptomyces)。并测定了菌株的生长曲线、抗生素抗性、所产黑色素的吸收光谱,为后期优化产黑色素的条件提供了理论基础。

  15. Inhibitory effects of melanin monomers, dihydroxyindole-2-carboxylic acid (DHICA) and dihydroxyindole (DHI) on mammalian tyrosinase, with a special reference to the role of DHICA/DHI ratio in melanogenesis.

    Science.gov (United States)

    Wilczek, A; Mishima, Y

    1995-04-01

    DOPAchrome tautomerase (DCT) is known to control the ratio of DHICA/DHI formed within the melanocyte, but physiologic significance of this activity is not yet fully elucidated. In this study the two melanin monomers are shown to inhibit with different efficacy the initial, tyrosinase-controlled, melanogenic reaction, namely conversion of L-tyrosine to DOPAchrome (2-carboxy-2,3-dihydroindole-5,6-quinone). This is demonstrated in the test tube assay system whereby formation of DOPAchrome is catalyzed by i) isolated premelanosomes (PMS), ii) tyrosinase-rich PMS glycoproteins, or iii) tyrosinase purified from fibroblasts transfected with human tyrosinase gene. Both DHI and DHICA suppress the conversion of L-tyrosine to DOPAchrome when added to reaction mixture but the inhibitory effect is far more strongly pronounced by DHI. DHI inhibits both activities of tyrosinase--tyrosine-hydroxylation and DOPA-oxidation--more strongly than DHICA. The different extent of inhibition is shown to reflect i) the ability of the two monomers to compete with tyrosinase substrates for the enzyme's active center and ii) the rate of interaction between melanin monomers and DOPAquinone. Consequently, we demonstrate that the tyrosinase-catalyzed DOPAchrome formation can be modulated by the ratio of DHICA/DHI among melanin monomers with the increased proportion of DHICA resulting in more efficient DOPAchrome formation. These results raise the possibility that DOPAchrome tautomerase plays a role in positive control of the tyrosinase-catalyzed early phase of melanogenesis.

  16. Central melanin-concentrating hormone influences liver and adipose metabolism via specific hypothalamic nuclei and efferent autonomic/JNK1 pathways.

    Science.gov (United States)

    Imbernon, Monica; Beiroa, Daniel; Vázquez, María J; Morgan, Donald A; Veyrat-Durebex, Christelle; Porteiro, Begoña; Díaz-Arteaga, Adenis; Senra, Ana; Busquets, Silvia; Velásquez, Douglas A; Al-Massadi, Omar; Varela, Luis; Gándara, Marina; López-Soriano, Francisco-Javier; Gallego, Rosalía; Seoane, Luisa M; Argiles, Josep M; López, Miguel; Davis, Roger J; Sabio, Guadalupe; Rohner-Jeanrenaud, Françoise; Rahmouni, Kamal; Dieguez, Carlos; Nogueiras, Ruben

    2013-03-01

    Specific neuronal circuits modulate autonomic outflow to liver and white adipose tissue. Melanin-concentrating hormone (MCH)-deficient mice are hypophagic, lean, and do not develop hepatosteatosis when fed a high-fat diet. Herein, we sought to investigate the role of MCH, an orexigenic neuropeptide specifically expressed in the lateral hypothalamic area, on hepatic and adipocyte metabolism. Chronic central administration of MCH and adenoviral vectors increasing MCH signaling were performed in rats and mice. Vagal denervation was performed to assess its effect on liver metabolism. The peripheral effects on lipid metabolism were assessed by real-time polymerase chain reaction and Western blot. We showed that the activation of MCH receptors promotes nonalcoholic fatty liver disease through the parasympathetic nervous system, whereas it increases fat deposition in white adipose tissue via the suppression of sympathetic traffic. These metabolic actions are independent of parallel changes in food intake and energy expenditure. In the liver, MCH triggers lipid accumulation and lipid uptake, with c-Jun N-terminal kinase being an essential player, whereas in adipocytes MCH induces metabolic pathways that promote lipid storage and decreases lipid mobilization. Genetic activation of MCH receptors or infusion of MCH specifically in the lateral hypothalamic area modulated hepatic lipid metabolism, whereas the specific activation of this receptor in the arcuate nucleus affected adipocyte metabolism. Our findings show that central MCH directly controls hepatic and adipocyte metabolism through different pathways. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

  17. Roles of glutamate signaling pathway in melanin transfer%谷氨酸信号通路对黑素细胞黑素转运的作用

    Institute of Scientific and Technical Information of China (English)

    高丽丽; 刘晶; 邹伟; 刘鹏; 张媛; 高船舟; 王楠; 宋智琦

    2012-01-01

    目的 探讨谷氨酸信号通路在黑素转运中的作用.方法 原代培养并纯化黑素细胞及角质形成细胞,免疫荧光显微镜观察离子型谷氨酸受体N-甲基-D-天冬氨酸受体1(NMDAR1)和N-甲基-D-天冬氨酸受体2A( NMDAR2A)在黑素细胞内的分布,共聚焦显微镜观察100 μmol/L NMDAR激动剂NMDA和100μmol/L拮抗剂地卓西平马来酸盐(dizocilpine maleate,MK801)作用5 min和1h后黑素细胞内钙离子浓度的变化以及100 μmol/L MK801对黑素细胞内微管蛋白的影响.结果 100 μmol/L NMDA可使黑素细胞内瞬时钙离子浓度升高,但100μmol/L MK801可使其降低;MK801先作用于黑素细胞5 min或1h阻断NMDA受体后,NMDA均不能再次诱导瞬时钙离子浓度升高.共聚焦显微镜观察发现MK801作用24 h后,胞内微管蛋白重新分布聚集于核周.扫描电镜观察发现100 μmol/L MK801作用于黑素细胞-角质形成细胞共培养体系48 h后,黑素细胞和角质形成细胞之间以及两种细胞表面的丝状伪足数量明显减少.共培养体系下,100μmol/L MK801作用后,角质形成细胞中的黑素含量明显降低,即从黑素细胞向角质形成细胞转移的黑素数量明显减少.结论 谷氨酸信号通路对黑素细胞胞内钙离子浓度、微管蛋白分布、黑素细胞伪足形成以及黑素细胞及角质形成细胞间的黑素转运具有一定调节作用.%Objective To investigate the roles of glutamate signaling pathway in melanin transfer.Methods Epidermal melanocytes and keratinocytes were isolated from human foreskin tissue followed by purification and primary culture.Immunofluorescence microscopy was conducted to observe the intracellular distribution of N-methy-D-aspartate receptor 1 (NMDAR1) and NMDAR2A in melanocytes.Some melanocytes were classified into 4 groups to be pretreated with MK801 (the NMDAR antagonist dizocilpine maleate) at 100μmol/L for 5 minutes followed by treatment with NMDA (an NMDAR agonist) at 100

  18. Berberine regulates melanin synthesis by activating PI3K/AKT, ERK and GSK3β in B16F10 melanoma cells.

    Science.gov (United States)

    Song, Young Chan; Lee, Yonghee; Kim, Hyeong Mi; Hyun, Moo Yeol; Lim, Yun Young; Song, Kye Yong; Kim, Beom Joon

    2015-04-01

    Berberine, an isoquinoline alkaloid, has a wide range of beneficial properties, including anti-bacterial, anti-inflammatory, anti-cancer, and cholesterol-lowering effects. Recently findings suggest that berberine improves glucose and lipid metabolism disorders. In the present study, we examined the mechanism underlying the inhibitory effect of berberine on α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells. The results showed that berberine attenuated α-MSH induction of the microphthalmia-associated transcription factor (MITF) and tyrosinase in a dose-dependent manner. To elucidate the mechanism underlying the inhibitory effect of berberine, we examined the effect of α-MSH-stimulated phosphorylation of PI3K/AKT, ERK, and GSK3β. The results showed that treatment with berberine resulted in a reduction in the phosphorylation of PI3K/AKT, ERK, and GSK3β. Taken together, the results suggested that berberine inhibits melanin synthesis and tyrosinase activity by downregulating the expression of MITF and tyrosinase. Thus, these findings may contribute to the potential application of berberine in the prevention and treatment of skin pigmentation disorders.

  19. 盐酸浸提木耳黑色素最佳工艺参数筛选研究%A Technique of Extracting Auriculair auricuia Melanin

    Institute of Scientific and Technical Information of China (English)

    张莲姬; 张敬爱

    2007-01-01

    天然黑色素(Melanin)是存在于植物、动物和微生物中的色素,是目前已知生物色素中最多的一类色素.黑色素具有抗氧化和防止衰老等功能,开发应用黑色素对食品工业具有重大意义.对黑木耳(Auriculair auricuia)中黑色素的提取方法进行了初步研究,将干黑木耳粉碎后以盐酸浸提,再经过滤、溶解、沉淀、离心、干燥得到黑木耳黑色素.通过试验筛选确定浸提盐酸的最佳浓度为3mol·L-1,正交试验确定黑色素的最佳提取条件为物料比1:25,提取时间1h,提取温度60℃,黑色素提取率为2.70%.

  20. Detection of Ca2+-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

    Directory of Open Access Journals (Sweden)

    Tigran R Petrosyan

    2016-01-01

    Full Text Available The study aims to confirm the neuroregenerative effects of bacterial melanin (BM on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12 or unilateral rubrospinal tract transection at the cervical level (C3–4 (group II; n = 12. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup and the remaining six rats were intramuscularly injected with saline (saline subgroup. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

  1. Control of ventricular ciliary beating by the Melanin Concentrating Hormone-expressing neurons of the lateral hypothalamus : a functional imaging survey.

    Directory of Open Access Journals (Sweden)

    Gregory eConductier

    2013-11-01

    Full Text Available The cyclic peptide Melanin-Concentrating Hormone (MCH is known to control a large number of brain functions in mammals such as food intake and metabolism, stress response, anxiety, sleep/wake cycle, memory and reward. Based on neuroanatomical and electrophysiological studies these functions were attributed to neuronal circuits expressing MCHR1, the single MCH receptor in rodents. In complement to our recently published work (Conductier et al. 2013 we provided here new data regarding the action of MCH on ependymocytes in the mouse brain. First, we establish that MCHR1 mRNA is expressed in the ependymal cells of the third ventricle epithelium. Second, we demonstated a tonic control of MCH-expressing neurons on ependymal cilia beat frequency using in vitro optogenics. Finally, we performed in vivo measurements of CSF flow using fluorescent micro-beads in wild-type and MCHR1 knockout mice. Collectively, our results demonstrated that MCH-expressing neurons modulate ciliary beating of ependymal cells at the third ventricle and could contribute to maintain cerebro-spinal fluid homeostasis.

  2. Melanin-concentrating hormone receptor 1 polymorphisms are associated with components of energy balance in the Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study.

    Science.gov (United States)

    Fontaine-Bisson, Bénédicte; Thorburn, James; Gregory, Anne; Zhang, Hongwei; Sun, Guang

    2014-02-01

    The melanin-concentrating hormone receptor 1 (MCHR1) is a G protein-coupled receptor that regulates energy balance and body composition in animal models. Inconsistent effects of MCHR1 polymorphisms on energy homeostasis in humans may partly be attributable to environmental factors. We examined the effect of 4 single nucleotide polymorphisms (rs133073, rs133074, rs9611386, and rs882111) in the MCHR1 gene on body composition as well as energy-related lifestyle factors (diet and physical activity). We also examined the effect of gene-lifestyle interactions on body composition. A total of 1153 participants (248 men and 905 women) from the cross-sectional Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study were genotyped by using probe-based chemistry validated assays. Diet and physical activity were estimated by using validated frequency questionnaires, and body composition was assessed by using dual-energy X-ray absorptiometry. Three polymorphisms (rs9611386, rs882111, and rs133073) were associated with differences in body-composition measurements (all P energy intakes (P = 0.02). A similar interaction was shown with rs882111 (P = 0.02). Interactions were also observed between each of these polymorphisms (rs9611386, rs882111, and rs133073) and physical activity score on body-composition measurements (all P gene are associated with differences in body composition and interact with physiologic and energy-related lifestyle factors.

  3. Central Melanin-Concentrating Hormone Influences Liver and Adipose Metabolism Via Specific Hypothalamic Nuclei and Efferent Autonomic/JNK1 Pathways

    Science.gov (United States)

    Imbernon, Monica; Beiroa, Daniel; Vázquez, María J.; Morgan, Donald A.; Veyrat–Durebex, Christelle; Porteiro, Begoña; Díaz–Arteaga, Adenis; Senra, Ana; Busquets, Silvia; Velásquez, Douglas A.; Al–Massadi, Omar; Varela, Luis; Gándara, Marina; López–Soriano, Francisco–Javier; Gallego, Rosalía; Seoane, Luisa M.; Argiles, Josep M.; López, Miguel; Davis, Roger J.; Sabio, Guadalupe; Rohner–Jeanrenaud, Françoise; Rahmouni, Kamal; Dieguez, Carlos; Nogueiras, Ruben

    2013-01-01

    BACKGROUND & AIMS Specific neuronal circuits modulate autonomic outflow to liver and white adipose tissue. Melanin-concentrating hormone (MCH)-deficient mice are hypophagic, lean, and do not develop hepatosteatosis when fed a high-fat diet. Herein, we sought to investigate the role of MCH, an orexigenic neuropeptide specifically expressed in the lateral hypothalamic area, on hepatic and adipocyte metabolism. METHODS Chronic central administration of MCH and adenoviral vectors increasing MCH signaling were performed in rats and mice. Vagal denervation was performed to assess its effect on liver metabolism. The peripheral effects on lipid metabolism were assessed by real-time polymerase chain reaction and Western blot. RESULTS We showed that the activation of MCH receptors promotes nonalcoholic fatty liver disease through the parasympathetic nervous system, whereas it increases fat deposition in white adipose tissue via the suppression of sympathetic traffic. These metabolic actions are independent of parallel changes in food intake and energy expenditure. In the liver, MCH triggers lipid accumulation and lipid uptake, with c-Jun N-terminal kinase being an essential player, whereas in adipocytes MCH induces metabolic pathways that promote lipid storage and decreases lipid mobilization. Genetic activation of MCH receptors or infusion of MCH specifically in the lateral hypothalamic area modulated hepatic lipid metabolism, whereas the specific activation of this receptor in the arcuate nucleus affected adipocyte metabolism. CONCLUSIONS Our findings show that central MCH directly controls hepatic and adipocyte metabolism through different pathways. PMID:23142626

  4. A new strategy to improve the predictive ability of the local lazy regression and its application to the QSAR study of melanin-concentrating hormone receptor 1 antagonists.

    Science.gov (United States)

    Li, Jiazhong; Li, Shuyan; Lei, Beilei; Liu, Huanxiang; Yao, Xiaojun; Liu, Mancang; Gramatica, Paola

    2010-04-15

    In the quantitative structure-activity relationship (QSAR) study, local lazy regression (LLR) can predict the activity of a query molecule by using the information of its local neighborhood without need to produce QSAR models a priori. When a prediction is required for a query compound, a set of local models including different number of nearest neighbors are identified. The leave-one-out cross-validation (LOO-CV) procedure is usually used to assess the prediction ability of each model, and the model giving the lowest LOO-CV error or highest LOO-CV correlation coefficient is chosen as the best model. However, it has been proved that the good statistical value from LOO cross-validation appears to be the necessary, but not the sufficient condition for the model to have a high predictive power. In this work, a new strategy is proposed to improve the predictive ability of LLR models and to access the accuracy of a query prediction. The bandwidth of k neighbor value for LLR is optimized by considering the predictive ability of local models using an external validation set. This approach was applied to the QSAR study of a series of thienopyrimidinone antagonists of melanin-concentrating hormone receptor 1. The obtained results from the new strategy shows evident improvement compared with the commonly used LOO-CV LLR methods and the traditional global linear model. 2009 Wiley Periodicals, Inc.

  5. Synaptic alpha-dystrobrevin: localization of a short alpha-dystrobrevin isoform in melanin-concentrating hormone neurons of the hypothalamus.

    Science.gov (United States)

    Hazai, Diana; Lien, Chun-Fu; Hajós, Ferenc; Halasy, Katalin; Górecki, Dariusz C; Jancsik, Veronika

    2008-03-27

    The expression of the two members of the dystrobrevin (DB) family in the adult brain was thought to be highly specific for the two main cell types: alpha-dystrobrevin (alpha-DB) and beta-dystrobrevin (beta-DB) has been identified as glial and neuronal proteins, respectively. In the present work we show that a subset of neurons in the hypothalamus contains alpha-DB. Comparative immunohistochemical studies with two alpha-DB antibodies of different specificity indicate that the neurons contain short alpha-DB isoform(s) alpha-DB-2 and/or alpha-DB-4. Immunoreactive multipolar or spindle-shaped neurons form clusters with bilateral symmetry, localized predominantly in the lateral hypothalamic area, with extensions into the zona incerta and the dorso-medial and ventro-medial hypothalamic region. alpha-DB immunoreactivity was localized in cell processes and at postsynaptic densities, furthermore in the endoplasmic reticulum within the perikarya. alpha-DB-positive neurons are beta-dystrobrevin immunoreactive, but alpha- and beta-DB do not co-localize with their usual molecular anchors like dystrophins or high molecular weight forms of utrophin. Colocalization with nNOS was also not observed. The pattern of alpha-DB immunoreactive neurons gave a perfect colocalization with melanin-concentrating hormone (MCH) neurons throughout the whole region studied. We propose that alpha-DB plays a role in a structure or regulation mechanism unique to MCH-expressing neurons.

  6. 祛斑汤对小鼠皮肤黑素合成影响的研究%Study on the Effect of Qu-ban Decoction On the Melanin Synthesis in Mouse Skin

    Institute of Scientific and Technical Information of China (English)

    李艳; 艾儒棣; 肖桦; 郝平生

    2012-01-01

    To observe the effect of Qu-ban Decoction on melanin synthesis in the female C57BL/6J mouse skin and provide the experimental basis for exploring deeply the mechanism of treating melasma by the prescription. Methods; Female C57BL/ 6J mice were randomly divided into the blank control group, the Qu-ban Decoction low dose group (10 g/kg) , the middle dose group (20 g/kg) , the high dose group (40 g/kg) and the vitamin C group. Take the skin from mice fed with drug for 30 days. Use immu-nohistochemical techniques to observe the melanin distribution and the result was analyzed using the one-way ANOVA statistically. Results : The melanocytes that contained the melanin granules were named positive cells. The average optical densities of positive cells of the high dose group and the middle dose group were lower than the blank control group. The difference between the high dose group, the middle dose group and the blank control group was significant statistically (P <0. 01) . Conclusion; The Qu-ban Decoction can inhibit the melanin synthesis and reduce the melanin distribution in female C57BI/6J mouse skin.%目的:观察祛斑汤对雌性C57BL/6J小鼠皮肤黑素合成的影响,为探索该方剂治疗黄褐斑机制提供实验依据.方法:将雌性C57BL/6J小鼠随机分成空白对照组、祛斑汤低(10 g/kg)、中(20 g/kg)、高剂量(40 g/kg)组、维生素C组.各组灌胃给药30 d后皮肤取材.采用免疫组化法观察小鼠皮肤黑素分布.结果:祛斑汤高、中剂量组黑素颗粒阳性反应的黑素细胞平均光密度低于空白对照组,差别有统计学意义(P<0.01).结论:祛斑汤能抑制雌性C57BI/6J小鼠皮肤中黑素合成、降低黑素分布.

  7. Study on Biological Activity of Melanin from Leaves of Guizhou Liquidambar Formosana Hance%黔产枫香树叶黑色素的生物活性研究

    Institute of Scientific and Technical Information of China (English)

    方玉梅; 张萍; 王毅红; 谭萍; 王盼; 赵宗城

    2015-01-01

    The experimental determination of the antimicrobial effected by slip method , and the antioxidant ability by salicylic acid colorimetric method and DPPH method , to evaluate the biological activity of melanin from leaves of Guizhou Liquidambar formosana Hance . The results showed that:the melanin from leaves of Guizhou Liquidambar formosana Hance had no inhibitory effect on Escherichia coli and Bacillus subtilis , had bacteriostasis to Staphylococcus aureus. Different concentrations of melanin from leaves of Guizhou Liquidambar formosana Hance had obvious effect scavenging rate of DPPH free radical and inhibition rate of ·OH free radical. And in a certain range of dilution , scavenging rate of DPPH free radical and inhibition rate of ·OH free radical, was positively related to concentration of melanin from leaves of Guizhou Liquidambar formosana Hance. To provide basis for further development and utilization of melanin from leaves of Guizhou Liquidambar formosana Hance.%采用纸片法测定其抑菌作用,并同时采用水杨酸比色法和DPPH法测定其抗氧化能力,来评价黔产枫香树叶黑色素的生物活性.结果表明:枫香树叶黑色素提取液对大肠杆菌和枯草芽孢杆菌没有抑菌作用,对金黄色葡萄球菌有抑菌作用.不同浓度的枫香叶黑色素对清除DPPH自由基和抑制·OH自由基都有明显的效果,且在一定的稀释范围内,枫香叶黑色素的浓度与DPPH自由基的清除率和·OH自由基的抑制率呈正相关.为黔产枫香叶黑色素的进一步开发利用提供参考.

  8. Characteristics and biosynthetic pathway of melanin in Ascochyta anemones%白头翁叶斑病菌黑色素的理化性质及其生物合成途径初步研究

    Institute of Scientific and Technical Information of China (English)

    苏丹; 吕国忠; 周如军; 杨红; 傅俊范

    2014-01-01

    对白头翁叶斑病菌胞壁结合黑色素和胞外黑色素进行了理化性质和红外光谱扫描测定,结果表明两者具有相似的理化性质,均易溶于KOH、H2 O2和NaClO,不溶于水、乙醇和丙酮。红外光谱分析表明,白头翁叶斑病菌YS-24菌株的胞壁结合黑色素与胞外黑色素为同一种类型的黑色素。DHN黑色素的特异性抑制剂—三环唑,对白头翁叶斑病菌黑色素的产生有明显的抑制作用;以白头翁叶斑病菌基因组DNA为模板,通过PCR扩增,得到了聚酮体合成酶基因的同源片段AaPKS,初步推断白头翁叶斑病菌黑色素合成属于DHN途径。%The characteristics of melanin,extracted from cell wall and fermented filtrate of Ascochyta anemones, were determined by diagnostic test and infrared spectroscopy. The results indicated that they have similar physical and chemical properties,and they are soluble in KOH,H2 O2 and NaClO,but not in water,ethanol and acetone. Infrared spectrum analysis showed that the wall-bound melanin and extracellular melanin belonged to the same type. Tricyclazole,a specific inhibitor of DHN melanin synthesis,could inhibit the fungal melanin’s biosynthesis of A.anemones. The homologous fragment of polyketide synthase gene (AaPKS)was amplified by PCR using A.anemones genomic DNA as a template. The results suggested that the melanin in A.anemones might be synthe-sized from DHN pathway.

  9. Emergence Time and Skin Melanin Spot Patterns Do Not Correlate with Growth Performance, Social Competitive Ability or Stress Response in Farmed Rainbow Trout

    Directory of Open Access Journals (Sweden)

    Manuel Gesto

    2017-06-01

    Full Text Available In wild salmonid fish, specific individual behavioral traits have been correlated with the timing of fry emergence from their gravel spawning nests; Early emerging fish display more aggressive behavior and have a higher probability of becoming socially dominant, compared to fish that emerge at a later stage. Apart from aggression and dominance, other behavioral and metabolic traits, such as boldness, metabolic rate, or growth, have also been linked to emergence time. Altogether, the traits of early- and late-emerging fish resemble those of the proactive and reactive stress-coping style, respectively. As proactive fish are considered more resilient to stress, it may be desirable to select these for aquaculture production. However, it is currently unclear to what extent the link between emergence time and stress-coping styles is maintained in the selective breeding of farmed fish. In the present study, eyed eggs from a commercial supplier were hatched, and larvae fractionated according to their emergence time. Later on, juvenile fish from different emergence fractions were subjected to a stress challenge and also tested to evaluate their competitive ability for food. Beyond some slight dissimilarities in the acute stress responses, emergence fraction displayed no correlation with growth rates, or the ability to compete for feed. Within the whole group of fish utilized in the experiments, no relationship between skin melanin spot pattern and growth performance, stress response intensity, or competitive ability was found. Altogether, the differences in physiological traits related to emergence time were not as strong as those found in earlier studies. It is hypothesized, that the origin and degree of domestication of the fish might be partly responsible for this. The predictive value of skin spots or emergence time to infer the fish stress coping style in farmed fish is also discussed.

  10. Melanin nanoparticles derived from a homology of medicine and food for sentinel lymph node mapping and photothermal in vivo cancer therapy.

    Science.gov (United States)

    Chu, Maoquan; Hai, Wangxi; Zhang, Zheyu; Wo, Fangjie; Wu, Qiang; Zhang, Zefei; Shao, Yuxiang; Zhang, Ding; Jin, Lu; Shi, Donglu

    2016-06-01

    The use of non-toxic or low toxicity materials exhibiting dual functionality for use in sentinel lymph node (SLN) mapping and cancer therapy has attracted considerable attention during the past two decades. Herein, we report that the natural black sesame melanin (BSM) extracted from black sesame seeds (Sesamum indicum L.) shows exciting potential for SLN mapping and cancer photothermal therapy. Aqueous solutions of BSM under neutral and alkaline conditions can assemble into sheet-like nanoparticles ranging from 20 to 200 nm in size. The BSM nanoparticles were encapsulated by liposomes to improve their water solubility and the encapsulated and bare BSM nanoparticles were both non-toxic to cells. Furthermore, the liposome-encapsulated BSM nanoparticles (liposome-BSM) did not exhibit any long-term toxicity in mice. The liposome-BSM nanoparticles were subsequently used to passively target healthy and tumor-bearing mice SLNs, which were identified by the black color of the nanoparticles. BSM also strongly absorbed light in the near-infrared (NIR) range, which was rapidly converted to heat energy. Human esophagus carcinoma cells (Eca-109) were killed efficiently by liposome-BSM nanocomposites upon NIR laser irradiation. Furthermore, mouse tumor tissues grown from Eca-109 cells were seriously damaged by the photothermal effects of the liposome-BSM nanocomposites, with significant tumor growth suppression compared with controls. Given that BSM is a safe and nutritious biomaterial that can be easily obtained from black sesame seed, the results presented herein represent an important development in the use of natural biomaterials for clinical SLN mapping and cancer therapy.

  11. Evaluation of the detection of melanin by the Fontana-Masson silver stain in tissue with a wide range of organisms including Cryptococcus.

    Science.gov (United States)

    Bishop, Justin A; Nelson, Ann Marie; Merz, William G; Askin, Frederic B; Riedel, Stefan

    2012-06-01

    It is not uncommon for surgical pathologists to encounter yeast and yeast-like organisms in tissue sections, and correct identification is imperative for guiding therapy. The Fontana-Masson silver stain for detecting melanin has been accepted as a relatively specific stain for diagnosing cryptococcosis in tissue based on few studies with limited numbers of organisms. This study was designed to test the value of the Fontana-Masson silver by investigating a large collection of tissues with infections that may mimic cryptococcosis. Cases of cryptococcosis and other infections that can morphologically mimic it were identified in the pathology archives of The Johns Hopkins Hospital and The Armed Forces Institute of Pathology. Overall, Fontana-Masson silver was positive in 25 (56%) of 45 cases, including infections caused by Cryptococcus neoformans (9/9), Coccidioides immitis (7/7), Blastomyces dermatitidis (4/10), Paracoccidioides brasiliensis (2/2), Lacazia loboi (1/1), and Rhinosporidium seeberi (1/1). The percentage of organisms staining varied widely, from less than 1% to 100%. Fontana-Masson silver was negative in all infections caused by Histoplasma capsulatum (n = 10), Histoplasma duboisii (n = 1), Sporothrix schenckii (n = 1), and the alga genus Prototheca (n = 2). Fontana-Masson silver was 100% sensitive for cryptococcosis. The specificity was low, however, with 5 of 9 noncryptococcal species being positive in some cases. These results need to be confirmed and extended to other isolates and species but it is clear that many organisms in the morphological differential diagnosis of cryptococcosis can be Fontana-Masson silver stain positive. Accordingly, results of the Fontana-Masson silver stain, especially a positive, should be interpreted cautiously and only in the context of the organism's morphological features and host factors.

  12. The role of melanin concentrating hormone (MCH in the central chemoreflex: a knockdown study by siRNA in the lateral hypothalamus in rats.

    Directory of Open Access Journals (Sweden)

    Ningjing Li

    Full Text Available Melanin concentrating hormone (MCH, a neuropeptide produced mainly in neurons localized to the lateral hypothalamic area (LHA, has been implicated in the regulation of food intake, energy balance, sleep state, and the cardiovascular system. Hypothalamic MCH neurons also have multisynaptic connections with diaphragmatic motoneurons and project to many central chemoreceptor sites. However, there are few studies of MCH involvement in central respiratory control. To test the hypothesis that MCH plays a role in the central chemoreflex, we induced a down regulation of MCH in the central nervous system by knocking down the MCH precursor (pMCH mRNA in the LHA using a pool of small interfering RNA (siRNA, and measured the resultant changes in breathing, metabolic rate, body weight, and blood glucose levels in conscious rats. The injections of pMCH-siRNA into the LHA successfully produced a ∼ 62% reduction of pMCH mRNA expression in the LHA and a ∼ 43% decrease of MCH levels in the cerebrospinal fluid relative to scrambled-siRNA treatment (P = 0.006 and P = 0.02 respectively. Compared to the pretreatment baseline and the scrambled-siRNA treated control rats, knockdown of MCH resulted in: 1 an enhanced hypercapnic chemoreflex (∼ 42 & 47% respectively; P < 0.05 only in wakefulness; 2 a decrease in body weight and basal glucose levels; and 3 an unchanged metabolic rate. Our results indicate that MCH participates not only in the regulation of glucose and sleep-wake homeostasis but also the vigilance-state dependent regulation of the central hypercapnic chemoreflex and respiratory control.

  13. Melanin-concentrating hormone (MCH) and gonadotropin-releasing hormones (GnRH) in Atlantic cod, Gadus morhua: tissue distributions, early ontogeny and effects of fasting.

    Science.gov (United States)

    Tuziak, Sarah M; Volkoff, Hélène

    2013-12-01

    Melanin-concentrating hormone (MCH) is classically known for its role in regulating teleost fish skin color change for environmental adaptation. Recent evidence suggests that MCH also has appetite-stimulating properties. The gonadotropin-releasing hormone (GnRH) peptide family has dual roles in endocrine control of reproduction and energy status in fish. Atlantic cod (Gadus morhua) are a commercially important aquaculture species inhabiting the shores of Atlantic Canada. In this study, we examine MCH and GnRH transcript expression profiles during early development as well as in central and peripheral tissues and quantify juvenile Atlantic cod MCH and GnRH hypothalamic mRNA expressions following food deprivation. MCH and GnRH3 cDNAs are maternally deposited into cod eggs, while MCH has variable expression throughout early development. GnRH2 and GnRH3 mRNAs "turn-on" during mid-segmentation once the brain is fully developed. For both MCH and GnRH, highest expression appears during the exogenous feeding stages, perhaps supporting their functions as appetite regulators during early development. MCH and GnRH transcripts are found in brain regions related to appetite regulation (telencephalon/preoptic area, optic tectum/thalamus, hypothalamus), as well as the pituitary gland and the stomach, suggesting a peripheral function in food intake regulation. Atlantic cod MCH mRNA is upregulated during fasting, while GnRH2 and GnRH3 transcripts do not appear to be influenced by food deprivation. In conclusion, MCH might be involved in stimulating food intake in juvenile Atlantic cod, while GnRHs may play a more significant role in appetite regulation during early development.

  14. Genetic deletion of melanin-concentrating hormone neurons impairs hippocampal short-term synaptic plasticity and hippocampal-dependent forms of short-term memory.

    Science.gov (United States)

    Le Barillier, Léa; Léger, Lucienne; Luppi, Pierre-Hervé; Fort, Patrice; Malleret, Gaël; Salin, Paul-Antoine

    2015-11-01

    The cognitive role of melanin-concentrating hormone (MCH) neurons, a neuronal population located in the mammalian postero-lateral hypothalamus sending projections to all cortical areas, remains poorly understood. Mainly activated during paradoxical sleep (PS), MCH neurons have been implicated in sleep regulation. The genetic deletion of the only known MCH receptor in rodent leads to an impairment of hippocampal dependent forms of memory and to an alteration of hippocampal long-term synaptic plasticity. By using MCH/ataxin3 mice, a genetic model characterized by a selective deletion of MCH neurons in the adult, we investigated the role of MCH neurons in hippocampal synaptic plasticity and hippocampal-dependent forms of memory. MCH/ataxin3 mice exhibited a deficit in the early part of both long-term potentiation and depression in the CA1 area of the hippocampus. Post-tetanic potentiation (PTP) was diminished while synaptic depression induced by repetitive stimulation was enhanced suggesting an alteration of pre-synaptic forms of short-term plasticity in these mice. Behaviorally, MCH/ataxin3 mice spent more time and showed a higher level of hesitation as compared to their controls in performing a short-term memory T-maze task, displayed retardation in acquiring a reference memory task in a Morris water maze, and showed a habituation deficit in an open field task. Deletion of MCH neurons could thus alter spatial short-term memory by impairing short-term plasticity in the hippocampus. Altogether, these findings could provide a cellular mechanism by which PS may facilitate memory encoding. Via MCH neuron activation, PS could prepare the day's learning by increasing and modulating short-term synaptic plasticity in the hippocampus. © 2015 Wiley Periodicals, Inc.

  15. A novel and selective melanin-concentrating hormone receptor 1 antagonist ameliorates obesity and hepatic steatosis in diet-induced obese rodent models.

    Science.gov (United States)

    Kawata, Yayoi; Okuda, Shoki; Hotta, Natsu; Igawa, Hideyuki; Takahashi, Masashi; Ikoma, Minoru; Kasai, Shizuo; Ando, Ayumi; Satomi, Yoshinori; Nishida, Mayumi; Nakayama, Masaharu; Yamamoto, Syunsuke; Nagisa, Yasutaka; Takekawa, Shiro

    2017-02-05

    Melanin-concentrating hormone (MCH), a cyclic neuropeptide expressed predominantly in the lateral hypothalamus, plays an important role in the control of feeding behavior and energy homeostasis. Mice lacking MCH or MCH1 receptor are resistant to diet-induced obesity (DIO) and MCH1 receptor antagonists show potent anti-obesity effects in preclinical studies, indicating that MCH1 receptor is a promising target for anti-obesity drugs. Moreover, recent studies have suggested the potential of MCH1 receptor antagonists for treatment of non-alcoholic fatty liver disease (NAFLD). In the present study, we show the anti-obesity and anti-hepatosteatosis effect of our novel MCH1 receptor antagonist, Compound A. Repeated oral administration of Compound A resulted in dose-dependent body weight reduction and had an anorectic effect in DIO mice. The body weight lowering effect of Compound A was more potent than that of pair-feeding. Compound A also reduced lipid content and the expression level of lipogenesis-, inflammation-, and fibrosis-related genes in the liver of DIO mice. Conversely, intracerebroventricular infusion of MCH caused induction of hepatic steatosis as well as increase in body weight in high-fat diet-fed wild type mice, but not MCH1 receptor knockout mice. The pair-feeding study revealed the MCH-MCH1 receptor system affects hepatic steatosis through a mechanism that is independent of body weight change. Metabolome analysis demonstrated that Compound A upregulated lipid metabolism-related molecules, such as acylcarnitines and cardiolipins, in the liver. These findings suggest that our novel MCH1 receptor antagonist, Compound A, exerts its beneficial therapeutic effect on NAFLD and obesity through a central MCH-MCH1 receptor pathway.

  16. Research of extraction technology of the melanin from core-shell of wild apricots using response surface analysis%响应面法对山杏核壳黑色素提取工艺的研究

    Institute of Scientific and Technical Information of China (English)

    李军; 张乔会; 蓝晶晶; 王建中

    2012-01-01

    With less utilization, core-shell of wild apricot was the scarps of production. On the basis of single factor experiments,the optimum conditions for the extraction of the melanin from core-shell of wild apricot were obtained through Box-Benhnken center-united experiment design and response surface methodology.The results showed that the optimum conditions of extraction of the melanin from core-shell of wild apricot were as follows: liquid ratio 1:20, temperature 60℃,alkali concentration tmol/L,time 4h.Under this condition,the maximal yield of melanin was up to 8.33%.%山杏核壳是生产中的下脚料,开发利用较少。以山杏核壳为原料提取黑色素,通过响应面法优化工艺条件。在单因素实验基础上选取实验因素与水平,根据Box—Benhnken中心组合实验设计原理采用四因素三水平的响应面分析法。得到最佳提取工艺为:料液比1:20,温度60℃,碱液浓度1mol/L,时间4h;在此条件下,提取得率可达8.33%。

  17. Influence of melanocytes in the ex-vivo reconstructed epidermal melanin unit following an acute UV irradiation; Role des melanocytes dans l'unite epidermique de melanisation reconstruite ex-vivo apres une irradiation UV aigue

    Energy Technology Data Exchange (ETDEWEB)

    Cario-Andre, M

    2000-11-15

    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)

  18. 甘草提取物对人黑素细胞黑素合成的影响%The impact of licorice on the melanin synthesis of human epidermal primary melanocytes

    Institute of Scientific and Technical Information of China (English)

    岳学状; 王大光; 朱文元

    2011-01-01

    目的: 评价甘草提取物对人原代黑素细胞酪氨酸酶及黑素合成的影响.方法:选择2.5、5.0、10.0、15.0、20.0、30.0 mg/L6个浓度的甘草作用于体外培养的人表皮黑素细胞72 h,分别测定细胞增殖活性、酪氨酸酶活性和黑素含量,western blot方法检测甘草作用后黑素细胞中酪氨酸酶蛋白的表达.结果: 甘草显著抑制黑素合成和酪氨酸酶活性,且呈浓度依赖性.结论: 甘草通过下调酪氨酸酶的表达抑制黑素合成和酪氨酸酶活性.%Objective: To assess the effects of licorice on melanin synthesis. Methods: Normal human melanocytes were isolated from human forskin and incubated with 2.5, 5.0, 10.0, 15.0, 20.0 and 30.0 fig/mL licorice for 72 h respectively, in vivo. The proliferation of melanocytes, melanin content and tyrosinase activity were measured. The protein expression of tyrosinase was evaluated with western blot technique. Results: Melanin synthesis was reduced and tyrosinase activity was significantly inhibited when licorice was cultured with melanocytes in a dose dependent manner, compared to control group. Conclusion: Licorice can inhibit melanogenesis and tyrosinase activity through downregulating the expression of tyrosinase.

  19. Inhibitory effects of salidroside and paeonol on tyrosinase activity and melanin synthesis in mouse B16F10 melanoma cells and ultraviolet B-induced pigmentation in guinea pig skin.

    Science.gov (United States)

    Peng, Li-Hua; Liu, Shuai; Xu, Shen-Yao; Chen, Lei; Shan, Ying-Hui; Wei, Wei; Liang, Wen-Quan; Gao, Jian-Qing

    2013-09-15

    Salidroside, the major active component of Rhodiola rosea, a herb with antioxidant, free radical scavenging and tyrosinase inhibitory effects, has been recently reported in protecting the kerationcytes from the UV radiation, suggesting the potential of this component in depigmentation. Paeonol is isolated from Moutan Cortex Radicis with anti-inflammation/microbial activities, was reported to induce the down-regulation of microphthalmia-associated transcription factor and subsequently tyrosinase. To testify the potential of these compounds as melanin formation inhibitors for hyperpigmentation therapy, the influence of salidroside and paeonol on pigmentation was investigated. With arbutin as a positive control, salidroside and paeonol were evaluated for their inhibitory effect on the cell viability, tyrosinase activity and melanin synthesis in B16F10 melanoma cells, as well as their effects in UVB-induced hyperpigmentation in brown guinea pig skins. It was demonstrated that the significant inhibition of salidroside (33.0%) and paeonol (22.2-30.9%) on the tyrosinase activity is slightly lower than that of arbutin (18.4-44.7%). However, salidroside exhibited the dose-dependent inhibition (30.6-42.0%) in melanin synthesis at a low concentration of 100 μM, paeonol and arbutin expressed inhibition rates of 27.4-37.2% and 25.8-45.6% within 500-1000 μM. The in vivo topical application of these compounds was demonstrated to obviously decrease the hyperpigmentation on UVB stimulated guinea pig skin. This study provided the original evidence for the salidroside and paeonol as therapeutic agents for pigmentation disorder and skin lightening, with further clinical investigation of these compounds in the field of depigmentation was suggested. Copyright © 2013 Elsevier GmbH. All rights reserved.

  20. Paradoxical (REM) sleep deprivation in mice using the small-platforms-over-water method: polysomnographic analyses and melanin-concentrating hormone and hypocretin/orexin neuronal activation before, during and after deprivation.

    Science.gov (United States)

    Arthaud, Sebastien; Varin, Christophe; Gay, Nadine; Libourel, Paul-Antoine; Chauveau, Frederic; Fort, Patrice; Luppi, Pierre-Herve; Peyron, Christelle

    2015-06-01

    Studying paradoxical sleep homeostasis requires the specific and efficient deprivation of paradoxical sleep and the evaluation of the subsequent recovery period. With this aim, the small-platforms-over-water technique has been used extensively in rats, but only rare studies were conducted in mice, with no sleep data reported during deprivation. Mice are used increasingly with the emergence of transgenic mice and technologies such as optogenetics, raising the need for a reliable method to manipulate paradoxical sleep. To fulfil this need, we refined this deprivation method and analysed vigilance states thoroughly during the entire protocol. We also studied activation of hypocretin/orexin and melanin-concentrating hormone neurones using Fos immunohistochemistry to verify whether mechanisms regulating paradoxical sleep in mice are similar to those in rats. We showed that 48 h of deprivation was highly efficient, with a residual amount of paradoxical sleep of only 2.2%. Slow wave sleep and wake quantities were similar to baseline, except during the first 4 h of deprivation, where slow wave sleep was strongly reduced. After deprivation, we observed a 124% increase in paradoxical sleep quantities during the first hour of rebound. In addition, 34% of hypocretin/orexin neurones were activated during deprivation, whereas melanin-concentrated hormone neurones were activated only during paradoxical sleep rebound. Corticosterone level showed a twofold increase after deprivation and returned to baseline level after 4 h of recovery. In summary, a fairly selective deprivation and a significant rebound of paradoxical sleep can be obtained in mice using the small-platforms-over-water method. As in rats, rebound is accompanied by a selective activation of melanin-concentrating hormone neurones.

  1. Study on the relationship between traditional chinese medicine constitution and skin's melanin, protoheme%中医体质与皮肤黑色素和血红素的关系研究

    Institute of Scientific and Technical Information of China (English)

    王雪; 徐艳明; 张宁; 郭鲁义; 李艳微; 刘国良

    2012-01-01

    目的:研究黑龙江地区女性皮肤黑色素、血红素与中医体质的关系.方法:选取1 05名女性志愿者,并根据王琦的“七分法”对其进行体质分型,并检测其不同部位皮肤的黑色素和血红素含量.结果:与平和组相比其它各组的黑色素值有减小的趋势,其中阳虚组的眼角部、湿热组的眼角部和前臂屈侧、气虚组的眼角部最为明显(P<0.05);与平和组相比其它各组的血红素值有减小的趋势,并且在各体质的面颊部和眼角部最明显(P<0.05).结论:不同中医体质对皮肤黑色素和血红素的影响不同.%Objective The article aims to study the relationship of women skin's Melanin, Protoheme and the constitution of traditional Chinese Medicine in the region of Hei Longjiang Province. Methods 105 female volunteer were chosen, they were classified physically according to Wang Qi's "Seven Classification", and the amounls of Melanin and Protoheme in the skin of the different part were detected- Results The value of Melanin in each group is decreasing comparing with the gentle group, among them the angle of the eye in sufficiency of yang group, the angle of the eye in damp heat group, forearm flexor side and the angle of the eye in deficiency of the vital energy group are the most obvious (P<0.05).The value of Protoheme in each group is decreasing comparing with the gentle group, and the cheek and the angle of the eye in each constitution are the most obvious (P<0.05). Conclusion The different constitution of traditional Chinese Medicine affects Melanin and Protoheme differently.

  2. 正交法优化花椒籽黑色素提取工艺研究%Research on Optimizing Extraction Method of Prickly Ash Seed Melanin by Orthogonal Array Design Tests

    Institute of Scientific and Technical Information of China (English)

    徐文秀; 王鹏; 王晓燕

    2014-01-01

    为了提高花椒籽的经济价值和社会效益,充分利用花椒资源,以运城花椒籽为原料,采用溶液浸提法提取花椒籽中黑色素。以提取液吸光度作为评价指标,考察提取过程中各因素对花椒籽黑色素得率影响。然后,用正交法优化花椒籽黑色素的提取工艺条件。结果表明:影响花椒籽黑色素得率主次因素为:提取温度>料液比>提取时间;正交法最优工艺参数:提取温度60℃,提取时间4.5 h,料液比1∶35(g/mL),提取次数1次,花椒籽黑色素提取液的吸光度达到最高值0.345。%In order to improve the economic benefits and social value of the prickly ash seed and fully use of this resource, the melanin was extracted from prickly ash seed by solvents in this paper. The influences of various factors on the obtaining ratio of prickly ash seed melanin were studied by single factor test , such as solution concentration, extraction temperature, ratio of solid to liquid and extraction time. Absorbance was selected as a substitute of melanin content. The optimize extraction process were determined by orthogonal experiments. The results showed that:the order of factors affected melanin yield from prickly ash seed was:temperature>ratio of solid to liquor>time. The optimum extraction temperature, the optimum extraction time, ratio of solid to liquid, extraction times were 60℃, 4.5 h, 1∶35(g/mL)and 1 times. The absorbance was as high as 0.345.

  3. Effects of SHIKONIN on Cel Proliferation and Melanin Transfer of Co-Cultured Human Melanocytes and Keratinocytes%紫草素对黑素转运的影响

    Institute of Scientific and Technical Information of China (English)

    解士海; 潘武辉; 宗国勇; 黄小雄

    2014-01-01

    目的:探讨紫草素(Sh)在人表皮共培养体系中对黑素转运的影响。方法采用MTT法测定紫草素对人黑素细胞(MC)与角质形成细胞(KC)共培养体系增殖的影响,利用荧光标记技术以及流式细胞仪研究紫草素对于黑素转运的影响。结果0.25μmol/L、0.5μmol/L和1μmol/L紫草素对于人表皮共培养体系增殖无影响,0.25μmol/L、0.5μmol/L和1μmol/L紫草素对于共培养体系中黑素转运有剂量依赖地促进作用。结论紫草素对于共培养体系中黑素转运有剂量依赖的促进作用。%Objective: To study the Effects of SHIKONIN on cellProliferation and Melanin transfer of Co-Cultured of melanocytes and keratinocytes Methods: MTT method, Flow cytometry were employed to measure the cellviability, melanin transfer of co-cultured melanocytes and keratinocytes Results No influence was observed on co-cultured melanocytes and keratinocytes cellproliferation by 0.25μmol/L, 0.5μmol/L, or 1μmol/L of SHIKONIN . The melanin transfer were clearly enhanced by SHIKONIN in a dose-dependent manner at concentrations of 0.25μmol/L, 0.5μmol/L, and 1μmol/L Conclusion SHIKONIN exhibits a dose-dependent enhancing effects on melanin transfer in co-cultured melanocytes and keratinocytes.

  4. Studing on the protection of macromolecule against light by melanin from engineering baeteria(E. Coli/p WSY)%工程菌所产黑色素对生物大分子光保护作用的研究

    Institute of Scientific and Technical Information of China (English)

    宁华

    2001-01-01

    研究了黑色素在防止紫外线照射引起的DNA双链断裂方面的作用,并探讨了该黑色素对B.t.的毒素蛋白和杀虫活性的光保护作用.%Studing melanin on the prevent function of DNA duplex breakage byUV irradiation, this paper discusses the protection of B.t. toxin protein and insecticidal activation against UV irradiation by melanin from engineering bacteria(E.Coli/p WSY).

  5. Identification of amino acids that are selectively involved in Gi/o activation by rat melanin-concentrating hormone receptor 1.

    Science.gov (United States)

    Hamamoto, Akie; Kobayashi, Yuki; Saito, Yumiko

    2015-04-01

    Many G-protein-coupled receptors (GPCRs) are known to functionally couple to multiple G-protein subfamily members. Although promiscuous G-protein coupling enables GPCRs to mediate diverse signals, only a few GPCRs have been identified with differential determinants for coupling to distinct Gα proteins. Mammalian melanin-concentrating hormone receptor 1 (MCHR1) couples to dual G-protein subfamilies. However, the selectivity mechanisms between MCHR1 and different subtypes of Gα proteins are unclear. Our previous studies demonstrated that mammalian MCHR1 couples to both Gi/o and Gq, whereas goldfish MCHR1 exclusively couples to Gq. In this study, we analyzed multiple sequence alignments between rat and goldfish MCHR1s, and designed three multisubstituted mutants of rat MCHR1 by replacing corresponding residues with those in goldfish MCHR1, focusing on regions around the cytosolic intracellular loops. By measurement of intracellular Ca(2+) mobilization, we found that two MCHR1 mutants, i2_6sub and i3_6sub, which contained six simultaneously substituted residues in the second intracellular loop or a combination of substituted residues in the third intracellular loop and fifth transmembrane domain, respectively, significantly reduced Gi/o-sensitive pertussis toxin responsiveness without altering Gq-mediated activity. Analyses of 10 other substitutions revealed that the multiple substitutions in i2_6sub and i3_6sub were necessary for Gi/o-selective responses. As judged by Gi/o-dependent GTPγS binding and cyclic AMP assays, i2_6sub and i3_6sub elicited phenotypes for impaired Gi/o-mediated signaling. We also monitored the dynamic mass redistribution (DMR) in living cells, which reveals receptor activity as an optical trace containing activation of all GPCR coupling classes. Cells transfected with i2_6sub or i3_6sub exhibited reduced Gi/o-mediated DMR responses compared with those transfected with MCHR1. These data suggest that two different regions independently affect

  6. Electron microscope study on the relationship between macrophages of the alevolar space and spheroid alveolar epithelial cells on mice after injection of squid-ink (sepia-melanin solution into the trachea

    Directory of Open Access Journals (Sweden)

    Suwa,Kiichi

    1977-02-01

    Full Text Available The relationship between alveolar macrophages and spheroid alveolar epithelial cells was studied with the electron microscope after injection of squid-ink solution into the trachea of the mouse. At 20 hours after injection of squid-ink solution slight degeneration was evident in alveolar macrophages with sepia-melanin particles being phagocytized with partial digestion by lysosmes. Furthermore, hardly any changes were seen in mitochondria and inclusion bodies of the spheroid alveolar epithelial cells. In contrast, at one week after injection of squid-ink solution, almost all alveolar macrophages were degenerated with destruction of the ectoplasm in which the ingested sepia-melanin particles were digested by lysosomes into fine particles, and the mitochondria of spheroid alveolar epithelial cells were degenerated and the inclusion bodies were hardly formed. At three weeks after injection of squid-ink solution, alveolar macrophages as well as speroid alveolar epithelial cells showed almost complete recovery of functional structure. As the phagocyte in the alveolar space, neutrophile leucocytes were also observed in addition to the so-called alveolar macrophage.

  7. Are melanin ornaments signals of antioxidant and immune capacity in birds?%黑色素羽毛装饰反映了鸟类的抗氧化和免疫能力吗?

    Institute of Scientific and Technical Information of China (English)

    Juan; MORENO; Anders; P.; MФLLER

    2006-01-01

    鸟类信号系统研究认为,不同于类胡萝卜素,基于黑色素的羽色装饰不需要昂贵的生理代价.然而,羽毛色素细胞的黑色素沉积与抗氧化能力和免疫系统有很强的联系,而抗氧化能力和免疫系统在提高有机体适合度方面具有重要的功能.黑色素细胞的生长对氧化环境压力十分敏感;并且,黑色素本身似乎就具有抗氧化剂的功能.相应地,把抗氧化剂用于以黑色素为基础羽色发育,还是用于其它方面例如免疫调节和免疫刺激等,个体也许必须对此做出权衡.组织中的抗氧化功能大多与代谢活动有关,也就是和自由基的最高水平有关.此外,人们发现,在哺乳动物中调节黑色素沉积的激素,即α-黑素细胞刺激素,在鸟类上皮组织的色素沉积中也具有同样的功能.这种进化保守的激素是免疫和炎症反应的一个重要介体.它下调前炎性细胞因子、免疫介导细胞因子和协同刺激分子,以及主要组织相容性复合体Ⅰ类分子在单核细胞的表达以及抗体的产生,而上调抑制因子白介素.黑色素在羽毛上的大量沉积,也可能反映出免疫系统在局部免疫应答的负调控能力.这些将黑色素沉积和抗氧化剂以及免疫功能联系起来的机制,表明基于黑色素的羽色信号具有一定的生理代价,这些对以往关于黑色素的优势作用的假说提出质疑[动物学报52(1):202-208,2006].%The assumption that melanin-based ornaments, in contrast to those that are carotenoid-based, are not physiologically costly has been pervasive in studies of avian signalling. However, melanin deposition in feather melanocytes has strong links with the capacity of the antioxidant and immune systems, two crucial fitness-enhancing organismic functions.Thus, melanocyte development is very sensitive to oxidative stress and melanin itself seems to function as an antioxidant.Accordingly, individuals may have to trade the use of

  8. DHN黑色素与玉米大斑病菌附着胞膨压形成的关系%Relationship Between DHN Melanin and Formation of Appressorium Turgor Pressure of Setosphaeria turcica

    Institute of Scientific and Technical Information of China (English)

    曹志艳; 贾慧; 朱显明; 董金皋

    2011-01-01

    [Objective] The objective of this study is to discuss the effect of intracellular DHN melanin ofSetosphaeria turcica on the appressorium turgor pressure generated and elucidate the invasive mechanism of S. turcica. [Method] In this research, the best conditions for appressorium formation of S. turcica were determined by inducing appressorium production. The appressorium cell wall pore sizes and turgor pressures of wild-type isolate 01-23 and melanin-deficient strains ΔSt3hnr of S. turcica were measured by a solute exclusion technique and incipient-cytorrhysis technique. [Result] The appressorium pore size of wild-type isolate 01-23 was 2.1-2.7 nm and it had a 5.4 MPa turgor pressure, while it was shown a range of 2.7-3.3 nm in melanin-deficient strainsΔSt3hnr and a lower pressure about 4.1 MPa. The results indicated that appressorium without melanin could not form a high turgor pressure resulting in losing the ability for penetrating. [ Conclusion] It is suggested that the melanin layer is significant in accumulation of excess turgor pressure and the turgor pressure of S. turcica play a major role in substance penetration.%[目的]探讨玉米大斑病菌胞内DHN黑色素在附着胞膨压产生过程中的作用,明确玉米大斑病菌的侵入机理.[方法]通过诱导玉米大斑病菌附着胞产生,确定附着胞形成的最佳条件,利用溶质排斥技术及incipient-cytorrhysis.技术对玉米大斑病菌野生型菌株01-23和黑色素缺失突变体△St3hnr附着胞细胞壁孔径大小和膨压进行测定.[结果]野生型菌株01-23细胞壁孔径范围是2.1-2.7nm,膨压在5.4MPa左右;黑色素缺失突变体△St3hnr细胞壁孔径范围是2.7-3.3nm,膨压在4.1MPa左右;缺乏黑色素的附着胞不能形成高膨压,丧失了穿透能力.[结论]黑色素层对溶质分子外渗的阻挡作用导致了附着胞高膨压的产生,膨压产生的机械穿透力在玉米大斑病菌穿透基质平面的过程中发挥了重要作用.

  9. Isolation and partial characterization of a mutant of Bacillus thuringiensis producing melanin Isolamento e caracterização parcial de um mutante de Bacillus thuringiensis produtor de melanina

    Directory of Open Access Journals (Sweden)

    Gislayne T. Vilas-Bôas

    2005-09-01

    Full Text Available A mutant (407-P of Bacillus thuringiensis subsp. thuringiensis strain 407 producing a melanin was obtained after treatment with the mutagenic agent ethyl-methane-sulfonate. Several microbiological and biochemical properties of the two strains were analyzed and the results were similar. The mutant 407-P was also incorporated into non-sterilized soil samples, recovered, easily identified, and quantified, what enables its use in ecology of B. thuringiensis.Um mutante (407-P da linhagem Bacillus thuringiensis subsp. thuringiensis 407 produtor de melanina foi obtido após tratamento com o agente mutagênico etil-metano-sulfonato. Diversas propriedades microbiológicas e bioquímicas das duas linhagens foram analisadas e os resultados foram similares. O mutante 407-P foi incorporado em amostras de solo não esterilizado, recuperado, facilmente identificado e quantificado, possibilitando seu uso em estudos de ecologia de B. thuringiensis.

  10. Hispolon Decreases Melanin Production and Induces Apoptosis in Melanoma Cells through the Downregulation of Tyrosinase and Microphthalmia-Associated Transcription Factor (MITF Expressions and the Activation of Caspase-3, -8 and -9

    Directory of Open Access Journals (Sweden)

    Yi-Shyan Chen

    2014-01-01

    Full Text Available Hispolon is one of the most important functional compounds that forms Phellinus linteus (Berkeley & Curtis Teng. Hispolon has antioxidant, anti-inflammatory, antiproliferative and anticancer effects. In this study, we analyzed the functions of hispolon on melanogenesis and apoptosis in B16-F10 melanoma cells. The results demonstrated that hispolon is not an enzymatic inhibitor for tyrosinase; rather, it represses the expression of tyrosinase and the microphthalmia-associated transcription factor (MITF to reduce the production of melanin in α-melanocyte-stimulating hormone (α-MSH-stimulated B16-F10 cells at lower concentrations (less than 2 μM. In contrast, at higher concentration (greater than 10 μM, hispolon can induce activity of caspase-3, -8 and -9 to trigger apoptosis of B16-F10 cells but not of Detroit 551 normal fibroblast cells. Therefore, we suggest that hispolon has the potential to treat hyperpigmentation diseases and melanoma skin cancer in the future.

  11. 维A酸对A375细胞黑素合成及酪氨酸酶蛋白表达的影响%Effects of retinoic acid on tyrosinase metabolism and melanin content expression in A375 cells

    Institute of Scientific and Technical Information of China (English)

    曹俊; 陈菊萍

    2014-01-01

    ObjectiveTo evaluate the effects of retinoic acid (RA) on melanin content, activity and protein expression of tyrosinase in A375 cells.MethodsCultured A375 cells were classiifed into 4 groups: RA group, 8-methoxypsoralen (8-MOP) group, hydroquinone group, and negative control group received no treatment. Melanin content and tyrosinase activity were determined by NaOH solubilization assay and dopa-oxidation assay respectively at 24, 48 and 72 hours after the addition of RA into the medium. Western blot was performed to detect the protein expression of tyrosinase in A375 cells after 24 hours culture with RA.ResultsThe melanin content and tyrosinase activity decreased in A375 cells after being treated with RA for 24, 48 and 72 hours (P<0.05). The protein (gray scale) in A375 cells at 24 hours expression level of tyrosinase in negative control group was 0.89 ± 0.085, decreased to 0.56 ± 0.044 (t=3.811,P<0.05) after additional treatment with RA.ConclusionRA down-regulates activity of tyrosinase, inhibits protein expression of tyrosinase in A375 cells, as well as the biosynthesis of melanin.%目的:探讨维A酸对人A375黑素瘤株细胞黑素含量、酪氨酸酶活性及蛋白表达的影响。方法将培养的A375细胞分为维A酸组、8-甲氧补骨脂素(8-MOP)组、氢醌组、阴性对照组(A375细胞只加入相应溶媒,不加入药物)分别培养,于24 h、48 h和72 h测定黑素含量及酪氨酸酶活性;培养24 h Western检测酪氨酸酶蛋白的变化。结果A375细胞加入维A酸24 h、48 h、72 h后黑素含量及酪氨酸酶活性均较阴性对照组下降(P<0.05)。阴性对照组A375细胞酪氨酸酶蛋白含量测定值为(0.89±0.085),维A酸组A375细胞酪氨酸酶蛋白含量为(0.56±0.044)(t=3.811,P<0.05)。结论维A酸能抑制人A375黑素瘤株细胞黑素含量、酪氨酸酶活性及蛋白表达。

  12. Molecular modifications of melanin f rom Lachnum and their antioxidative activities%粒毛盘菌黑色素分子修饰及其抗氧化活性

    Institute of Scientific and Technical Information of China (English)

    李兰; 袁怀波; 李盛兰; 叶明

    2016-01-01

    By using carboxymethylation and sulfation to modify the homogeneous component melanin (LIM205) from Lachnum sp ,a water-soluble melanin carboxymethylate (CLIM205) and a melanin sulfate(SLIM205) were obtained and the modifications were successfully verified by UV and FT-IR spectra .LIM205 was insoluble in water under the temperature of 30 ℃ ,however ,it became a water-soluble melanin after carboxymethylation and sulfation . The water solubility of CLIM205 and SLIM205 were 3.75 g and 2.06 g . The abilities of LIM205 ,CLIM205 and SLIM205 to scavenge OH・ ,O2 - ・ ,DPPH・ and to chelate Fe2+were tested ,and the antioxidative activities in vitro were also evaluated .At the same dosage ,the antioxidative activities