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Melanins are heterogenous biopolymers produced by many macro and microorganisms. They enhance the ecological fitness of the producer organisms by improving their virulence and protecting them from radiation, osmotic and heat stresses. Fungi synthesise either DOPA or DHN melanin and deposit them on their cell walls. Some fungal isolates produce water soluble melanin (pyomelanin) which is excerted out of the hyphae into the surrounding environment. Pyomelanin, a polymer of homogentisate, exhibits antimicrobial, UV screening, antioxidative, and anti-inflammatory activities and recent studies also show that pyomelanin could find use in space travel as radiation shield. However, scant literature is available on fungi with ability to produce pyomelanin. We report for the first time that Amorosia littoralis occurs as a root endophyte in mangrove species including Avicennia marina , Bruguiera cylindrica and Bruguiera gymnorhiza and produces pyomelanin. Considering the various technological uses of pyomelanin, this study underscores the need to explore fungi of different habitats to identify hyperproducers and to obtain chemically diverse pyomelanin. [ABSTRACT FROM AUTHOR]

Coat colour largely determines the market demand for several cat breeds. The KIT proto-oncogene (KIT) gene is a key gene controlling melanoblast differentiation and melanogenesis. KIT mutations usually cause varied changes in coat colour in mammalian species. In this study, we used a pair of single-guide RNAs (sgRNAs) to delete exon 17 of KIT in somatic cells isolated from two different Chinese Li Hua feline foetuses. Edited cells were used as donor nuclei for somatic cell nuclear transfer (SCNT) to generate cloned embryos presenting an average cleavage rate exceeding 85%, and an average blastocyst formation rate exceeding 9.5%. 131 cloned embryos were transplanted into four surrogates, and all surrogates carried their pregnancies to term, and delivered 4.58% (6/131) alive cloned kittens, with 1.53% (2/131) being KIT -edited heterozygotes (KIT D17/+ ). The KIT D17/+ cats presented an obvious darkness reduction in the mackerel tabby coat. Immunohistochemical analysis (IHC) of skin tissues indicated impaired proliferation and differentiation of melanoblasts caused by the lack of exon17 in feline KIT. To our knowledge, this is the first report on coat colour modification of cats through gene editing. The findings could facilitate further understanding of the regulatory role of KIT on feline coat colour and provide a basis for the breeding of cats with commercially desired coat colour. • Cloned cats with KIT edited by CRISPR-Cas9 presented a distinct coat colour variation. • Western blotting showed impaired proliferation and differentiation of melanoblasts in back skin of clone cats. • The findings provide a basis for the breeding of cats with commercially desired coat colour. [ABSTRACT FROM AUTHOR]

Tyrosol (4-hydroxyphenylethanol) is a phenolic compound used in the pharmaceutical and chemical industries. However, current supply methods, such as extraction from natural resources and chemical synthesis, have disadvantages from the viewpoint of cost and environmental protection. Here, we developed a tyrosol-producing Escherichia coli cell factory from a high-tyrosine-producing strain by expressing selected tyrosine decarboxylase-, tyramine oxidase (TYO)-, and medium-chain dehydrogenase/reductase (YahK)-encoding genes. The genes were controlled by the strong T7 promoter and integrated into the chromosome because of the advantages over plasmid-based systems. The strain produced a melanin-like pigment as a by-product, which is suggested to be formed from 4-hydroxyphenylacetaldehyde (a TYO product/YahK substrate). By using a culture medium containing a high concentration of glycerol, which was reported to enhance NADH supply required for YahK activity, the final titer of tyrosol reached 2.42 g/L in test tube-scale cultivation with a concomitant decrease in the amount of pigment. These results indicate that chromosomally integrated and T7 promoter-controlled gene expression system in E. coli is useful for high production of heterologous enzymes and might be applied for industrial production of useful compounds including tyrosine and tyrosol. [Display omitted] [ABSTRACT FROM AUTHOR]

The most lethal form of skin cancer is cutaneous melanoma, a tumor that develops in the melanocytes, which are found in the epidermis. The treatment strategy of melanoma is dependent on the stage of the disease and often requires combined local and systemic treatment. Over the years, systemic treatment of melanoma has been revolutionized and shifted toward immunotherapeutic approaches. Phototherapies like photothermal therapy (PTT) have gained considerable attention in the field, mainly because of their straightforward applicability in melanoma skin cancer, combined with the fact that these strategies are able to induce immunogenic cell death (ICD), linked with a specific antitumor immune response. However, PTT comes with the risk of uncontrolled heating of the surrounding healthy tissue due to heat dissipation. Here, we used pulsed laser irradiation of endogenous melanin-containing melanosomes to induce cell killing of B16-F10 murine melanoma cells in a non-thermal manner. Pulsed laser irradiation of the B16-F10 cells resulted in the formation of water vapor nanobubbles (VNBs) around endogenous melanin-containing melanosomes, causing mechanical cell damage. We demonstrated that laser-induced VNBs are able to kill B16-F10 cells with high spatial resolution. When looking more deeply into the cell death mechanism, we found that a large part of the B16-F10 cells succumbed rapidly after pulsed laser irradiation, reaching maximum cell death already after 4 h. Practically all necrotic cells demonstrated exposure of phosphatidylserine on the plasma membrane and caspase-3/7 activity, indicative of regulated cell death. Furthermore, calreticulin, adenosine triphosphate (ATP) and high-mobility group box 1 (HMGB1), three key damage-associated molecular patterns (DAMPs) in ICD, were found to be exposed from B16-F10 cells upon pulsed laser irradiation to an extent that exceeded or was comparable to the bona fide ICD-inducer, doxorubicin. Finally, we could demonstrate that VNB formation from melanosomes induced plasma membrane permeabilization. This allowed for enhanced intracellular delivery of bleomycin, an ICD-inducing chemotherapeutic, which further boosted cell death with the potential to improve the systemic antitumor immune response. [Display omitted] • Pulsed laser irradiation triggers vapor nanobubbles around endogenous melanosomes. • Laser-induced vapor nanobubbles can kill B16-F10 cells in a spatial-selective manner. • Laser-induced B16-F10 cell death involves caspase-3/7 activity and phosphatidylserine exposure. • Laser-induced vapor nanobubbles elicit the exposure and release of hallmarks of immunogenic cell death. • Laser-induced vapor nanobubbles promote the delivery of membrane-impermeable bleomycin in B16-F10 cells. [ABSTRACT FROM AUTHOR]

Pollution of water resources has become a global environmental problem, and the massive discharge of high-color printing and dyeing wastewater has caused serious harm to the natural environment. In this work, we have used repeated alkali solubilization and acid precipitation for an agricultural and forestry by-product, bilberry kernel shells, to obtain Mountain apricot shell Melanin (Mas-Mel), which can be used for the adsorption of cationic dyes. By graft copolymerization with a natural sugar-based polymer, κ-carrageenan (κCA), in a mild manner, we have prepared the adsorbent, Mountain apricot shell Melanin /κ-carrageenan (Mas-Mel/κCA) hydrogel beads, which were physically and chemically analyzed using a variety of spectroscopic and microscopic techniques. The optimum conditions for methylene blue (MB) adsorption and malachite green (MG) on Mas-Mel/κCA hydrogel were: contact time 150 min, adsorbent dose 60 mg, pH 6–7. The results of the adsorption tests followed the Pseudo-second order kinetics (R2 = 0.97 and 0.95), and the maximum adsorption capacity of MB and MG based on the Langmuir isotherm model was 48.63 mg/g and 37.84 mg/g, respectively. In addition, the prepared hydrogel beads still exhibited a high reusability and removal rate (∼50 %) after three consecutive 400-minute cyclic adsorption-resolution cycles. Our results may provide a new strategy for the development of green bio-based adsorbent materials and industrial dye wastewater treatment. [Display omitted] • Mountain apricot shell melanin (Mas-Mel) can be used for cationic dye adsorption. • Novel hydrogels obtained by grafting Mas-Mel into κ-carrageenan networks. • Removal of mobile cationic dyes using Mas-Mel/κCA beads as fixed bed filler. • Removes approx. 50 % of the dye even after 400 min of continuous adsorption-desorption. [ABSTRACT FROM AUTHOR]

Recent concerns regarding the clinical accuracy of pulse oximetry in dark-skinned patients, specifically in detecting occult hypoxaemia, have motivated research on this topic and recently reported in this journal. We provide an overview of the technical aspects of the issue, the sources of inaccuracy, and the current regulations and limitations. These insights offer perspectives on how pulse oximetry can be improved to address these potential limitations. [ABSTRACT FROM AUTHOR]

Retinal drug delivery is a challenging, but important task, because most retinal diseases are still without any proper therapy. Drug delivery to the retina is hampered by the anatomical and physiological barriers resulting in minimal bioavailability after topical ocular and systemic administrations. Intravitreal injections are current method-of-choice in retinal delivery, but these injections show short duration of action for small molecules and low target bioavailability for many protein, gene based drugs and nanomedicines. State-of-art delivery systems are based on prolonged retention, controlled drug release and physical features (e.g. size and charge). However, drug delivery to the retina is not cell-specific and these approaches do not facilitate intracellular delivery of modern biological drugs (e.g. intracellular proteins, RNA based medicines, gene editing). In this focused review we highlight biological factors and mechanisms that form the basis for the selective retinal drug delivery systems in the future. Therefore, we are presenting current knowledge related to retinal membrane transporters, receptors and targeting ligands in relation to nanomedicines, conjugates, extracellular vesicles, and melanin binding. These issues are discussed in the light of retinal structure and cell types as well as future prospects in the field. Unlike in some other fields of targeted drug delivery (e.g. cancer research), selective delivery technologies have been rarely studied, even though cell targeted delivery may be even more feasible after local administration into the eye. [Display omitted] [ABSTRACT FROM AUTHOR]

The earlobes of chickens exhibit a range of colors, but there has been relatively little research on the formation of structural blue earlobes. Previous results showed that the structural color earlobes were related to the interplay between melanin and collagen in light reflection. To investigate the metabolic differences in these earlobe colors, we conducted nontargeted liquid chromatograph mass spectrometer (LC-MS) for metabolomic sequencing on structural blue (Green and Blue groups) and nonstructural color (Black group) earlobes tissue of Jiangshan black-bone chickens. The content detection in earlobe tissues of different groups shows that there were significant differences in melanin and collagen content between the Black and Green group. The metabolome identified a total of 6,102 mass spectroscopic peaks and ultimately identified 919 annotated metabolites. Variable importance in the projection (VIP) analysis identified the common differential expressed metabolites (DMs) "Tyr Thr Ala Glu" among the 3 groups. By combining those DMs with differentially expressed genes (DEGs) in our previous transcriptome data from the same sample, and associated with KEGG pathway analysis, multiple pathways related to melanogenesis and collagen metabolism were enriched across the 3 groups. By analyzing the metabolites and genes in these pathways, as well as the interaction network diagram of DEGs, we identified some key genes, Wnt Family Member 6 (WNT6), Transcription Factor 7 (TCF7), Proopiomelanocortin (POMC) and Calcium/Calmodulin Dependent Protein Kinase II Alpha (CAMK2A), and some key DMs like DG (11M3/9M5/0:0) and gentisic acid. The differential gene expression and metabolic levels affect the production of melanin and collagen, leading to differences in the content in melanin and the thickness of the collagen layer between earlobe colors, while the thickness of the collagen layer could affect light scattering, ultimately resulting in different colored earlobes in Jiangshan black-bone chickens. [ABSTRACT FROM AUTHOR]

We previously identified a dark blue appearance through the skin of abdomen, especially the colored chicken breeds, called hyperpigmentation of the visceral peritoneum (HVP) which characterized by intense pigmentation of connective tissue in the visceral peritoneum. The HVP has recently garnered increasing attention due to its negative impact on carcass appearance, and been an important concern in the poultry industry, especially for the Chinese yellow-feathered broilers. In this study, we measured the in vivo HVP at different time points, and analyzed the correlation between the HVP in vivo and postmortem. Then, established an accurate and reliable HVP phenotypic measuring method in vivo for early selection in chickens and analyzed the association of phenotypic variations with the in vivo HVP traits with growth traits. The results showed that the in vivo HVP at 21 d of age in chickens have a high heritability (h2 = 0.452) through estimating genetic parameters, and in vivo HVP levels at 21 and 42 d were both significantly associated with those postmortem in chickens, suggesting that directional selection on reducing HVP can be implemented as early as at 21 d in the breeding and production of chickens. Although, we found HVP had no effect on the body weight at 1 d, it could significantly reduce the body weight at 21, 42, 70 d and 91 d in chickens. This suggests HVP not only has a negative effect on carcass traits, but also significantly reduces the production in the poultry industry. [ABSTRACT FROM AUTHOR]

Tokishakuyakusan (TSS), a traditional Kampo medicine, can effectively alleviate symptoms unique to women, such as menstrual pain and menopausal symptoms, and this effect is believed to be related to its ability to increase the secretion of female hormones. TSS is also believed to be effective against skin pigmentation. However, no studies have examined the effect of TSS on pigmentation. In this study, we conducted basic research to determine the effects of TSS on pigmentation. Female HRM-2 mice were given free access to a normal diet or a TSS-containing diet for 7 weeks. For 3 weeks starting from the 4th week of treatment, the back of the skin was irradiated with ultraviolet (UV) light, and the melanin level was measured. The expression levels of melanogenesis-related genes and inflammatory markers in the skin were analyzed. The melanin level in the skin of the mice exposed to UV radiation was approximately three times greater than that in the skin of the mice in the non-UV-irradiated group, confirming pigmentation due to UV irradiation. The protein expression levels of tyrosinase (Tyr), tyrosinase-related protein-1 (Tyrp1), and dopachrome tautomerase (Dct), which are important for melanin production, were significantly greater in the UV irradiation group than in the non-UV irradiation group. In contrast, the amount of skin melanin in the mice treated with TSS was significantly lower than that in the UV-irradiated group, and the expression levels of melanogenesis-related enzymes were also lower. Furthermore, TSS significantly decreased the expression of microphthalmia transcription factor (Mitf), a transcription factor for melanogenesis-related enzymes, and the inflammatory cytokines interleukin-1β and interleukin-6. TSS inhibits melanin production in melanocytes by suppressing the increase in the expression of melanogenesis-related enzymes caused by UV irradiation. These findings suggested that this effect of TSS is exerted through the combined regulation of MITF expression and anti-inflammatory responses. [Display omitted] • Tokishakuyakusan (TSS) inhibits melanin production caused by UV irradiation. • TSS suppresses the expression of melanogenesis-related enzymes in the skin. • TSS decreases the expression of Mc1r and Mitf in the skin. • TSS was suppressed the increase in inflammatory cytokines due to UV irradiation. • TSS is expected to have clinical application in the treatment of photoaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • RNAi of bursicon signaling gene fades adult pigmentation. • The dark area in the resulting beetles is decreased. • Expression of sclerotin biosynthesis genes is enhanced in the treated beetles. • RNAi of sclerotin biosynthesis gene can rescue the reduced dark area. In arthropods, the binding of a bursicon (encoded by burs and pburs) heterodimer or homodimer to a leucine-rich repeat-containing G protein coupled receptor LGR2 (encoded by rk) can activate many physiological processes, especially cuticle pigmentation during insect ecdysis. In the current paper, we intended to ascertain whether bursicon signaling mediates body coloration in the 28-spotted larger potato ladybird, Henosepilachna vigintioctomaculata , and if so, by which way bursicon signal governs the pigmentation. The high expression of Hvburs , Hvpburs and Hvrk occurred in the young larvae, pupae and adults, especially in the head and ventral nerve cord. RNA interference (RNAi) aided knockdown of Hvburs , Hvpburs or Hvrk in the prepupae caused similar phenotypic defects. The pigmentation of the resultant adults was affected, with significantly reduced dark areas on the sternums. Moreover, the accumulated mRNA levels of two sclerotin biosynthesis genes, aspartate 1-decarboxylase gene Hvadc and N-β-alanyldopamine synthase gene Hvebony , were significantly increased in the Hvburs , Hvpburs or Hvrk RNAi beetles. Furthermore, depletion of either Hvadc or Hvebony could completely rescue the impaired coloration on the sternums of Hvpburs RNAi adult. Our results supported that bursicon heterodimer-mediated signal regulate cuticle pigmentation. The bursicon signaling may tune the ratio of melanins (dark/black, brown) to sclerotins (light yellow, colorless) exerting its regulative role in the pigmentation of H. vigintioctomaculata sternums. [ABSTRACT FROM AUTHOR]

The healing of diabetic wounds is significantly impeded due to severe oxidative stress and hindered angiogenesis, presenting a major challenge to clinical treatment. In this context, we introduces a novel hydrogel dressing strategy that uniquely combines α-lipoic acid-modified chitosan (LAMC) and melanin nanoparticles (MNPs). This innovative hydrogel, LAMC@MNPs, is formulated to gel under ultraviolet (UV) light without the need for a photoinitiator, simplifying the preparation process and potentially enhancing safety. Our experimental results demonstrate that the LAMC@MNPs hydrogel not only exhibits superior skin adhesion, with an average strength of 56.59 ± 3.16 KPa, but also effectively alleviates oxidative stress and accelerates vascular regeneration and wound healing. This is achieved by promoting cell migration and scavenging free radicals, addressing the critical barriers in diabetic wound care. The combination of these materials and their functional benefits presents a promising new approach to diabetic wound treatment. [ABSTRACT FROM AUTHOR]

Melanin is a dark pigment from the group of phenolic or indole polymers with inherent biocompatibility and antioxidant capacity. In extremophilic lichen Lobaria pulmonaria , melanin is responsible for protective properties against hostile environments. Herein, the ability of melanin extracted from L. pulmonaria to counteract oxidative stress and related damages was studied in the mouse diaphragm, the main respiratory muscle. Initial in vitro experiments demonstrated ultraviolet (UV)-absorbing, antioxidant and metal chelating activities of melanin. This melanin can form nanoparticles and stabile colloidal system at concentration of 5 μg/ml. Pretreatment of the muscle with melanin (5 μg/ml) markedly reduced UV-induced increase in intracellular and extracellular reactive oxygen species (ROS) as well as antimycin A-mediated enhancement in mitochondrial ROS production accompanied by lipid peroxidation and membrane asymmetry loss. In addition, melanin attenuated suppression of neuromuscular transmission and alterations of contractile responses provoked by hydrogen peroxide. Thus, this study shed the light on the perspectives of the application of a lichen melanin as a protective component for treatment of skeletal muscle disorders, which are accompanied with an increased ROS production. [Display omitted] [ABSTRACT FROM AUTHOR]

The primary feathers of ducks have important economic value in the poultry industry. This study quantified the primary feather phenotype of Nonghua ducks, including the primary feathers' length, area, distribution of black spots, and feather symmetry. And genome-wide association analysis was used to screen candidate genes that affect the primary feather traits. The genome-wide association study (GWAS) results identified the genetic region related to feather length (FL) on chromosome 2. Through Linkage disequilibrium (LD) analysis, candidate regions (chr2: 115,246,393–116,501,448 bp) were identified and were further annotated to 5 genes: MRS2, GPLD1, ALDH5A1, KIAA0319 , and ATP9B. Secondly, candidate regions related to feather black spots were identified on chromosome 21. Through LD analysis, the candidate regions (chr21: 163,552–2,183,853 bp) were screened and further annotated to 47 genes. Among them, STK4, CCN5 , and YWHAB genes were related to melanin-related pathways or pigment deposition, which may be key genes affecting the distribution of black spots on feathers. In addition, we also screened 125 genes on multiple chromosomes that may be related to feather symmetry. Among them, significant SNPs on chromosome 1 were further identified as candidate regions (chr1: 142,118,209–142,223,605 bp) through LD analysis and annotated into 2 genes, TGFBRAP1 and LOC113839965. These results reported the genetic basis of the primary feather from multiple phenotypes, and offered valuable insights into the genetic basis for the growth and development of duck feathers and feather color pattern. [ABSTRACT FROM AUTHOR]

• The addition of melanin to the PVA/CMC/PPy blend resulted in an irregular rise in the n value compared to the blend without melanin. • The presence of melanin led to an enhancement in the optical conductivity of the PVA/CMC/PPy blended polymer. • The NLO parameters showed an irregular improvement. • The I-V characteristic emphasized the non-ohmic behavior of all blends. • The system mainly displays the Poole-Frenkel emission mechanism, with the exception of the doped blend with x = 0.1 at 293–333 K, which demonstrates Schottky emissions. Polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) have been used as polymeric matrices to create polymeric nanocomposite films that contain polypyrrole (PPY) and melanin as fillers. The structure of the PVA/CMC/PPy/x wt % melanin blends was analyzed using the X-ray diffraction technique. The scanning electron microscopy technique was used to investigate the morphologies of the blends. The highest absorbance and reflectance spectra were observed when the melanin content reached 0.25 and 0.2 % wt %, respectively. The smallest direct and indirect optical band gaps are (4.91, 4.44) eV and (4.22, 3.79, 2.34) eV, respectively, achieved when the melanin content was 0.25 wt%. The blend doped with 0.15 wt% PANi yielded the highest refractive index values (1.396 at λ = 600 nm). The optical dielectric constant values of the blends exhibited irregular improvement when the PVA/CMC/PPy blended polymer was filled with varying quantities of melanin. The blend doped with 0.15 wt% melanin exhibits the highest optical conductivity values in the visible range. The blend of PVA/CMC/PPy with a melanin concentration of 0.15 or 0.2 wt% demonstrated the highest nonlinear optical parameters. The blend of PVA/CMC/PPy with a melanin concentration of 0.15 or 0.2 wt% demonstrated the highest nonlinear optical parameter. Based on the observed behavior of the I-V characteristic, the possibility of ohmic conduct ions or space charge limited conduct ions is ruled out in all blends. The charge transport mechanisms that take place in different blends under varying temperatures were examined. These outcomes suggest the opportunity of employing the created blended polymer in capacitive energy storage, optoelectronic devices and photocatalytic application. [ABSTRACT FROM AUTHOR]

In this study, a novel water-insoluble bacterial melanin was first isolated and purified from the fermentation culture of Gram-negative bacterial Rhizobium radiobacter ATCC 1333 through the thermal acid-alkali treatment. The highest extracellular melanin production was 3.46 ± 0.07 g·L−1 when the initial glutamic acid concentration was 10 g·L−1. The molecular weight of the purified bacterial melanin (TPBM) was 686 g/mol. The molecular formula (C 34 H 30 N 4 O 12) and chemical structure were defined based on FT-IR, MALDI-TOF/MS, Py–GC/MS NMR (1H and 13C), and elemental analyses. Furthermore, UV–vis spectroscopy results indicated that TPBM showed maximum absorption at around 222 nm. TPBM was easily soluble in alkaline solutions, but hardly-soluble in aqueous and majority of the organic solvents. In addition, TPBM was stable to temperature, light, reducing agent, and most metal ions. However, TPBM could be bleached when subjected to the action of oxidants and precipitated with FeCl 3 and AgNO 3. TPBM (50 µg·mL−1) possessed high DPPH free radical (89.74% ± 1.10%) and hydroxyl scavenging properties (84.12% ± 1.31%). Finally, TPBM displayed potential anti-bacterial properties against E. coli , S. aureus , A. baumanii , and M. albican. These results provided a theoretical basis for the later development and utilization of TPBM. [Display omitted] • Microbial melanin was separated and purified from the submerged fermentation of Rhizobium radiobacter. • The molecular formula (C 34 H 30 N 4 O 12) and chemical structure of the melanin were defined. • The melanin was stable to temperature, light, reducing agent, and most metal ions. • The melanin possessed potential antioxidant and anti-bacterial activities. [ABSTRACT FROM AUTHOR]

CmrA, as transcription factor for regulating DHN-melanin synthesis, controls melanin synthesis gene expression, and also regulate growth, development, stress response and virulence of plant fungi. However, little is known about the roles of CmrA on infection structure formation, penetration and pathogenicity of pear fungal Alternaria alternata. Here, we identified c mrA gene in A. alternata and assigned as AacmrA , sequence alignment and phylogenetic analysis revealed that AacmrA is highly conserved among fungi and encoded protein contain two Cys2His2 zinc finger motifs and one Zn(II)2Cys6 zinc cluster protein motif. ΔAacmrA severely decreased melanin production and DHN melanin synthesis related genes expression. Deletion of AacmrA impaired the morphology of spore and hyphae. Spore germination and appressorium formation induced by hydrophobicity surfaces and fruit wax significantly decreased in Δ AacmrA mutant. Δ AacmrA mutants were more sensitive than the wild type to osmotic stress and cell wall inhibitors, especially more sensitive to oxidative stress. In addition, lesion diameter of pear fruit wound inoculated with the Δ AacmrA mutant was reduced by 40.8% compared with the wild type 12 d after inoculation. All findings of this study suggested that AacmrA is required for melanin biosynthesis, infection structure formation, and pathogenicity in A. alternata. [ABSTRACT FROM AUTHOR]

We explored the capability of low-frequency Electron Paramagnetic Resonance (EPR) to noninvasively detect melanin (a stable semiquinone free radical) in the human skin. As previous in vitro studies on biopsies suggested that the EPR signal from melanin was different when measured in skin melanomas or benign nevi, we conducted a prospective first-in-man clinical EPR study in patients with skin lesions suspicious of melanoma. EPR spectra were obtained using a spectrometer operating at 1 GHz, with a surface coil placed over the area of interest. Two clinical studies were carried out: 1) healthy volunteers (n = 45) presenting different skin phototypes; 2) patients (n = 88) with skin lesions suspicious of melanoma (n = 100) requiring surgical resection. EPR data obtained before surgery were compared with histopathology results. The method was not sensitive enough to measure differences in melanin content due to changes in skin pigmentation. In patients, 92% of the spectra were analyzable. The EPR signal of melanin was significantly higher (p < 0.0001) in melanoma lesions (n = 26) than that in benign atypical nevi (n = 62). A trend toward a higher signal intensity (though not significant) was observed in high Breslow depth melanomas (a marker of skin invasion) than in low Breslow lesions. To date, no naturally occurring free radicals have been detected by low-frequency EPR systems adapted for clinical studies. Here, we demonstrated for the first time the ability of this technology to detect an endogenous free radical, opening new avenues for evaluating clinical EPR as a potential aid in the diagnosis of pigmented skin lesions. [Display omitted] • Skin lesion characterization before surgery could accelerate patient management. • Melanin is an endogenous stable semiquinone free radical. • First-in-man clinical EPR study to detect noninvasively melanin in skin lesions. • Study on 100 lesions suspicious of melanoma requiring surgical resection. • EPR signal of melanin was higher in melanoma compared to atypical nevi. [ABSTRACT FROM AUTHOR]

Introduction: Vitiligo is a dermatological disease that affects about 0.38% to 2.9% of the world population. Currently, the main treatments used for vitiligo involve the use of topical drugs such as corticosteroids and calcineurin inhibitors, phototherapy, systemic treatment with steroids and even surgical grafts and, in acute cases, depigmenting treatments. Natural products are an alternative for the treatment of vitiligo: mamacadela (Brosimum gaudichaudii), a plant rich in furanocoumarins, and sowthistle (Sonchus oleraceus), rich in phenolic substances, are already used to treat vitiligo. There are also popular reports of the use of a preparation containing coffee (Coffea sp) and sunflower seed (Helianthus annuus) to treat vitiligo.Case Report: A female patient, 28 years old, diagnosed with vitiligo, reported having obtained a positive result in the repigmentation of the pale white patches after the daily use of a preparation containing coffee and sunflower seed for about one year.Discussion: Data from the scientific literature demonstrated that chemical constituents of these plants, such as chlorogenic acid and its isomers, which have antioxidant and anti-inflammatory action, and substances such as linoleic acid and vitamins E and B, which help in the process of melanin formation on the skin, may be responsible for the observed repigmentation of the patches. Further research on this case report is important for scientific validation and the development of new therapeutic options, especially with less adverse effects, in the treatment of vitiligo. [ABSTRACT FROM AUTHOR]

Yohimbine hydrochloride (YH) is a prescription drug to treat erectile dysfunction. It also had potential in fighting high blood pressure and diabetic neuropathy as well as promoting weight loss. The aim of the study is to investigate the anti-melanogenic function of yohimbine hydrochloride and reveal its underlying molecular mechanism. B16F10 mouse melanoma cells, Melan-A murine melanocyte, Zebrafish embryos and C57BL/6 mouse ear skins were treated with different concentrations of YH. The extracellular and cellular melanin content was detected by spectrometry. The expression of microphthalmia-associated transcription factor (MITF), tyrosinase and the activities of Wnt/β-catenin and p38/MAPK signal pathways were determined by RT-qPCR, Western blot analysis and immunofluorescent staining. Melanin production could be effectively inhibited by YH at the safe concentration in vitro and in vivo. Q-PCR and WB results showed that the expression of MITF and tyrosinase were strongly downregulated after YH treatments along with the reduction of tyrosinase activity. YH markedly inhibited β-catenin nuclear accumulation and p38 phosphorylation in B16F10 cells compared with the untreated controls. Importantly, the increase of MITF expression induced by β-catenin activator BIO and p38 activator anisomycin could be fully reversed by YH treatments. These results indicate that YH can function as an anti-melanogenic agent, at least in part, by inhibiting Wnt/β-catenin and p38/MAPK signal pathways. Therefore, YH may be potentially used as a skin-whitening compound for preventing hyperpigmentation disorders in the future. • This manuscript extends the novel function of YH as the anti-melanogenic agents. • It is first to report YH could inhibit β-catenin nuclear accumulation and p38 phosphorylation. • YH downregulates MITF expression via regulating Wnt/β-catenin and p38/MAPK signal pathways. [ABSTRACT FROM AUTHOR]

The main objective of this study was to prepare functional allopurinol (ALP) incorporated biomaterials using mungbean starch, polyvinyl alcohol, melanin (MEL), and plasticizers. Prepared biomaterials were characterized by FE-SEM and FT-IR analysis. Photothermal conversion efficiencies and ALP release properties of biomaterials were evaluated with NIR laser irradiation. When biomaterials were irradiated with the NIR laser, temperatures increase of MEL-added biomaterials were higher than those of MEL-non-added biomaterials. After NIR laser irradiation, ALP release rates of MEL-added biomaterials were 1.62 times faster than those of MEL-non-added biomaterials. In addition, ALP release using an artificial skin was increased by NIR laser irradiation. ALP release from biomaterials followed Fickian diffusion mechanism, while ALP release using an artificial skin followed a non-Fickian diffusion mechanism. Xanthine oxidase inhibitory (%) for MEL-added biomaterials with/without the addition of GL and XL were 47.5%, 61.7%, and 65.1%, respectively. [ABSTRACT FROM AUTHOR]

Nicotinamide mononucleotide (NMN) is a representative anti-aging drug that, after long-term administration in mice, causes an increase in energy and lipid metabolism, improves eye function, immune response, and increases insulin sensitivity. However, the effects of NMN on skin pigmentation are still unknown. In this study, we aimed to demonstrate the effects of NMN on melanogenesis. NMN was applied to both young and aged melanocytes, and melanin production, protein expression, and mRNA levels were analyzed. A reconstituted human skin model was used to validate the effect of NMN on melanogenesis in vivo. NMN treatment showed no apparent effects on young melanocytes, however, in aged melanocytes, a marked reduction in melanin production was observed. NMN treatment also efficiently reduced melanin production in a reconstituted human skin with aged melanocytes. Genome-wide analysis showed the downregulation of melanogenesis-related cyclic adenosine monophosphate (cAMP)/Wnt signaling in aged melanocytes. Moreover, NMN treatment downregulated forskolin-induced expression of melanogenesis-related proteins, tyrosinase (TYR), tyrosinase-related protein (TRP)− 1, and TRP-2. Nicotinamide adenine dinucleotide (NAD+), an NMN product within the cells, also reduced cAMP/Wnt signaling in aged melanocytes. SLC12A6 was the most highly expressed gene among the SLC12A family members in melanocytes and was significantly influenced by NMN or NAD+ treatment, indicating that SLC12A6 protein is an NMN transporter in melanocytes. NMN reduces melanogenesis in aged melanocytes by downregulating the signaling of melanogenesis-associated receptors. Therefore, NMN is a human-friendly anti-melanogenic agent with the potential to aid in aging-related hyperpigmentation therapy. • NMN treatment downregulated melanin production in aged melanocytes, but not young melanocytes. • NMN treatment downregulated melanin production in a human skin equivalent reconstructed with aged primary melanocytes. • NMN treatment downregulated the expression of genes involved in cAMP/Wnt signaling for melanogenesis in aged melanocytes. • NAD+, an NMN product within the cells, downregulated both melanin production and cAMP/Wnt signaling. [ABSTRACT FROM AUTHOR]

Tibetan kefir grain as the starter of milk fermentation has been applied as functional food with many bioactive characteristics. In this study, the milk whey product (TKG-MW) was obtained through the milk fermentation of Tibetan kefir grain containing the dominant Lactobacillus , Acetobacter , and Bacillus after 3 and 6 days of cultivation. Antioxidant, anti-inflammatory, and melanogenesis inhibition capacities under TKG-MW treatment were analyzed. Results revealed that the antioxidation of TKG-MW at 6 days of fermentation was higher than that at 3 days of fermentation according to the DPPH and ABTS + radical scavenging analysis. However, the anti-inflammation of TKG-MW was only observed at 6 days of fermentation by using lipopolysaccharide-stimulated RAW 264.7 macrophages. The inhibition of mushroom tyrosinase activity by TKG-MW was demonstrated. The decrease of melanin content was verified using α-melanocyte-stimulating hormone-stimulated B16-F10 cell. The real-time quantitative reverse transcription polymerase chain reaction result indicated that the mRNA levels of Tyr, Trp-1, and Trp-2 of the B16 cell involved in melanin synthesis were down-regulated over a two-fold change by the TKG-MW treatment. Additionally, the protein expressions of Tyr, Trp-1, Trp-2, and Mitf of the B16 cell were reduced with the TKG-MW treatment. Organic acids, such as lactic acid, succinic acid, 3-phenyllactic acid, l -pyroglutamic acid, and malic acid, were identified by liquid chromatography-mass spectrometry in TKG-MW and were found to significantly inhibit tyrosinase activity. To the best of our knowledge, this work is the first to report melanogenesis suppression by TKG-MW. Results suggested that the fermentation product of TKG could be applied as a depigmenting agent in food and cosmetics. [ABSTRACT FROM AUTHOR]

An 11-year-old spayed female Miniature Schnauzer dog was presented with loss of a claw caused by a nail bed mass. Histopathological evaluation revealed that the mass comprised neoplastic squamous cells with abundant cytoplasmic melanin pigment. Immunohistochemically, the neoplastic cells were positive for cytokeratin and negative for vimentin and ionized calcium-binding adaptor molecule 1, supporting a diagnosis of pigmented squamous cell carcinoma. To our knowledge, this is the first report of subungual pigmented squamous cell carcinoma in animals. [ABSTRACT FROM AUTHOR]

The occurrence of darkened skin and 'greying' fillet colouration has been reported with farmed barramundi and is considered a negative quality trait of the product for consumers. It was evident that the problem was present in both fresh and salt-water farmed barramundi, but there was very little occurrence in wild barramundi. Although such darkened skin colouration is understood to be related to skin melanin content, the issue with the greying of the flesh is less well understood. To explore the nature of this problem a series of qualitative assays were undertaken that demonstrated that the 'greying' of the dorsal fillet flank in barramundi is also caused by melanin. By combining the qualitative assessment with a range of colour assessment methods (L*a*b* meter, light-box photography, and digital scanning), we were able to examine and verify the extent of the melanisation in farmed fish. From examination of the level of variability of 'greying' in farmed fish, it was evident that the problem was greater in some samples than others, but with no obvious causes. The influence of incident light and background colour on skin and fillet melanisation was examined using two colorimetric methods and quantitative melanin analysis in a comprehensive trial. Those studies showed that background colour and to a lesser extent incident light had a significant effect on skin colour, but not on fillet colour. Due to the observation of increased levels of melanin in the fat cells of the dorsal flank of the fillet, an aligned experiment was undertaken to attempt to manipulate the melanin synthesis pathway by changing the levels of melanin substrate (the amino acid tyrosine) or substrate competitors (the amino acid tryptophan) or by attempting to influence rate-limiting enzyme (tyrosinase) co-factors, like copper content in the diet. The use of high-levels of poultry oil as a substitute to fish oil had also been implicated and were included as an additional treatment to be evaluated. None of the dietary treatments impacted skin colour or were able to resolve the issue of fillet greying and showed no differences between treatments. Some minor changes in colour and melanin levels were observed in response to some of the dietary treatments, indicating that some potential may exist to manipulate the fillet melanin content via the diet, but further work on this issue is required. • Farmed barramundi can be associated with a higher level of melanised skin and grey hue to the dorsal flank of the fillet. • Qualitative studies identified that the greyness in the fillet was caused by melanin. • Tank background colour and shading (UV light attenuation) influenced skin colour and to a lesser degree fillet colour. • The relationship between skin colour and fillet colour was not strong. • Manipulation of dietary nutrients involved in the tyrosinase enzyme pathway did not affect either skin or fillet colour. [ABSTRACT FROM AUTHOR]

Skin color is a crucial economic trait for commercial fishes. Recently, excluding wild-type grayish black alternations, pufferfish (Takifugu fasciatus) with white and black colors were observed in China. The molecular mechanism underlying these fascinating skin color differences is still unknown. We examined T. fasciatus individuals with three different skin colors, namely, control (C), white (W), and black (B), utilizing histology, proteomics, metabolomics, and Western blotting techniques. Histological observations revealed that melanin content plays a pivotal role in determining skin color. Proteomics analysis comparing control and black individuals revealed significant enrichment of melanin-related proteins, including phosphatidylinositol 3-kinase (Pi3k), solute carrier family 2 (Slc27a), dual specificity phosphatase (Dusp), and Wnt8a. Similarly, compared to controls, white individuals exhibited significant enrichment of Ellis-van-Creveld syndrome protein 1 (Evc), smoothened (Smo). A total of 11 proteins that were linearly correlated with changes in melanin content were identified, and 4 proteins, namely, Wnt8a, Slc27a, Mucin-2 (Muc2), and gamma-glutamyl transferase (Ggt5), were selected for validation via Western blotting. Metabolomic analysis revealed strong correlations between L-tyrosine, 4- N -methyltransferase, indole-3-acetate salt, L -phenylalanine, L-threonine, L-glutamic acid, indole, and skin color formation in T. fasciatus. Notably, joint proteomic and metabolomic analyses revealed significant enrichment of ABC transporters across all three skin colors of T. fasciatus. Additionally, we identified 25 differentially expressed metabolites, suggesting potential feed additives such as adrenosterone and 1-(3-ethyl-2,4-dihydroxy-6-methoxyphenyl) butan-1-one for adjusting skin color. This research enhances our understanding of fish skin color formation mechanisms and provides valuable insights for cultivating fish with specific skin colors. [Display omitted] • According to histological observing melanin content affects the skin color of T. fasciatus. • Exploring the mechanism of synthesis and decomposition of melanin in white individuals. • Exploring the mechanism of synthesis and decomposition of melanin in black individuals. • Screening of biomarkers linearly correlated with melanin content. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rapid and sensitive detection strategy of melanin has been established based on the nanocomposite AuNCs@ZIF-8. • The confined space of ZIF-8 limited the rotation and vibration of the AuNCs, decreasing their free motion. • Compared to the AuNCs, AuNCs@ZIF-8 exhibited a more pronounced quenching effect. • The AuNCs@ZIF-8 was applied to detect melanin in human hair. Melanin is an important marker of human disease and aging. It is necessary to quickly and sensitively detect melanin. In this study, a novel fluorescence strategy for the rapid and sensitive detection of melanin was established based on a nanocomposite (AuNCs@ZIF-8) consisting of gold nanoclusters (AuNCs) and a zeolite-imidazole framework (ZIF-8). The confined space of ZIF-8 restricted the rotation and vibration of the AuNCs, reducing their free movement. Thus, the non-radiative transition energy of the AuNCs decreased, leading to stronger fluorescence intensity of AuNCs@ZIF-8. Melanin acted as an electron acceptor while AuNCs@ZIF-8 acted as an electron donor. Through electron transfer, the fluorescence of the AuNCs@ZIF-8 was effectively quenched. Compared to the AuNCs, AuNCs@ZIF-8 showed a more significant quenching effect. Therefore, using the fluorescence value of AuNCs@ZIF-8 as the reporting part, the melanin level could be detected by the fluorescence quenching in 24 min. The range of linearity of the approach was 0.1–500.0 μg⋅mL−1, and the detection limit of melanin is 0.03 μg⋅mL−1. [ABSTRACT FROM AUTHOR]

Asymmetric pyrene derivative (Py3) exhibits synergetic ROS generation under NIR light exposure. Py3 demonstrates superior photodynamic therapy (PDT) effectiveness compared to Chlorin e6. Moreover, melanin, known to shield melanocytes during PDT with UV/visible excitation, remained minimally affected by two-photon irradiation in both cells and 3D pheroids. Also, Py3 inhibited tumor growth in a B16F10 and 4T1 model mice during two-photon PDT. [Display omitted] • Revealed novel pyrene derivatives as effective two-photon photosensitizers. • Implemented a simple, flexible design strategy with easy synthetic methods. • Generated potent ROS under NIR light exposure and hypoxic conditions. • Achieved notable PDT success in melanin pigment-protected melanoma models. • Successfully inhibited tumor growth in mouse models. Photodynamic therapy (PDT) is primarily applied in the treatment of skin diseases. However, conventional PDT is less effective for melanoma, a type of skin cancer that contains melanin pigment, due to melanin's broad absorption spectrum in the ultraviolet–visible region. This reduces the effectiveness of traditional photosensitizers (PSs) in PDT. Here, we introduced pyrene based two-photon (TP) PSs that are easy to synthesize. Among the π-extended pyrene derivatives, we have confirmed the synergetic generation of reactive oxygen species (ROS) with asymmetric pyrene (Py3). We proposed a mechanism explaining the higher ROS generation efficiency of Py3 compared with that of the symmetric derivatives through theoretical calculations. Py3 effectively stains the plasma membrane of melanoma cells and demonstrates superior PDT efficacy compared with Chlorin e6. As the melanin content increases in melanoma cells, cell death significantly decreases under visible light excitation; notably, it is minimally affected by TP irradiation at 750 nm. In 3D multicellular tumor spheroids with a high melanin content, Py3 showed high PDT efficacy through TP irradiation, whereas under visible light irradiation, PDT efficacy decreased. In experiments involving the injection of Py3 into the tail of mice with B16F10 and 4 T1 tumor models, followed by TP-PDT, we observed significant inhibition of tumor growth and high biocompatibility. Our results indicate a promising TP-PDT method for treating melanomas. [ABSTRACT FROM AUTHOR]

The aim of this review article is to summarize the latest findings and current understanding of the origin of melanin in the retinal pigment epithelium (RPE), its function within the RPE, its role in the pathogenesis of age-related macular degeneration (AMD), its effect on retinal development, and its potential therapeutic benefit in the treatment of AMD. A comprehensive search of peer-reviewed journals was conducted using various combinations of key terms such as "melanin," "retinal pigment epithelium" or "RPE," "age-related macular degeneration" or AMD," "lipofuscin," "oxidative stress," and "albinism." Databases searched include PubMed, Scopus, Science Direct, and Google Scholar. 147 papers published between the years of 1957 and 2023 were considered with an emphasis on recent findings. AMD is thought to result from chronic oxidative stress within the RPE that results in cellular dysfunction, metabolic dysregulation, inflammation, and lipofuscin accumulation. Melanin functions as a photoscreener, free radical scavenger, and metal cation binding reservoir within the RPE. RPE melanin does not regenerate, and it undergoes degradation over time in response to chronic light exposure and oxidative stress. RPE melanin is important for retinal development and RPE function, and in the aging eye, melanin loss is associated with increased lipid peroxidation, inflammation, and the accumulation of toxic oxidized cellular products. Therefore, melanin-based treatments may serve to preserve RPE and retinal function in AMD. The pathogenesis of AMD is not fully understood, but RPE dysfunction and melanin loss in response to chronic oxidative stress and inflammation are thought to be primary drivers of the disease. Due to melanin's antioxidative effects, melanin-based nanotechnology represents a promising avenue for the treatment of AMD. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2-MBO analogs showed stronger tyrosinase inhibition potency than phenylthiourea. • In B16F10 cells, 2-MBO analogs strongly inhibited melanin production. • Their anti-melanogenic effect was due to inhibition of cellular tyrosinase activity. • Their tyrosinase inhibitory activity was due to chelation of tyrosinase copper ions. • 2-MBO analogs are promising candidates for treating skin-pigmentation disorders. Tyrosinase is a metalloenzyme that contains copper(II) ions. We designed and synthesized eight known low-molecular-weight 2-mercaptobenzoxazole (2-MBO) analogs as tyrosinase inhibitors. Our focus was on the mercapto functional group, which interacts with copper ions. Analogs 1 – 3 exhibited mushroom tyrosinase inhibitory activity at the nanomolar level and demonstrated strong potency with extremely low half-maximal inhibitory concentration (IC 50) values of 80–90 nM for l -dopa and 100–240 nM for l -tyrosine. Analogs 2 , 4 , and 5 showed the most potent anti-melanogenic effects in B16F10 cells, and their mode of action was demonstrated by kinetic analysis. Their anti-melanogenic effects were similar to the tyrosinase inhibition results, suggesting that their anti-melanogenic effects could be attributed to their tyrosinase inhibitory ability. Experiments using copper-chelating activity assays and changes in tyrosinase inhibitory activity with and without CuSO 4 demonstrated that 2-MBO analogs inhibit tyrosinase activity by chelating the copper ions of tyrosinase. In conclusion, the 2-MBO analogs show potential as anti-melanogenic agents with potent tyrosinase inhibitory activity. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) are oxygen-free radicals produced from the metabolic reactions in living organisms. ROS with moderate levels in cells are the cell signaling molecules involved in cellular proliferation, survival, differentiation, and gene expression. Nevertheless, it can cause oxidative damage through increased excessive ROS generation. Melanin, a natural pigment found in all biological kingdoms, is known to contribute to different biological processes and to protect organisms from adverse environmental conditions. Its antioxidant capacity has been broadly studied and demonstrated. This study aimed to find out how the melanin extracted from the cuttlefish Sepia pharaonis ink (MCI) affected the antioxidant activities of Clone-9 cells. The results showed that 300 and 500 μg/mL MCI decreased the intracellular ROS level by 89.8% and 78.6%, respectively. MCI could promote mitochondrial functions and the increase in mitochondrial membrane potential. Furthermore, the gene expression and activities of master antioxidant enzymes, namely SOD, CAT, and GPx, were also increased by at least 20% by MCI inducement. The mechanistic study found that this protective capacity is mediated by enhanced translocation of Nrf2 from the cytoplasm to the nucleus due to MCI induction of activation of the Nrf2 transcription factor. Our study might contribute to throwing light on the molecular mechanism of the MCI's cytoprotective capacity under oxidative stress conditions, which may provide a foundation for the application of MCI in both the pharmaceutical and food industries. This helps to build awareness about using cephalopod ink, which most processing industries and consumers throw away as a byproduct. [Display omitted] • Melanin extracted from the cuttlefish (Sepia pharaonis) ink (MCI) decreased the intracellular ROS level. • MCI elevated the mitochondrial membrane potential, thereby enhancing mitochondrial functions. • Through the Nrf2 pathway, MCI increased the expression of genes and activities of antioxidant enzymes (SOD, CAT, and GPx). • MCI could be applied as a new preservation strategy in the food industry or as a dietary supplement. [ABSTRACT FROM AUTHOR]

Surfactants occupy a prominent place in the domestic and industrial fields. Amino acid surfactants have attracted attention as alternatives to petrochemical-based surfactants owing to their good biocompatibility and biodegradability. Conventional amino acid surfactants with structures having only acyl linkages lack multifunctionality. Therefore, novel amino acid surfactants must be developed to achieve this feature. Inspired by melanogenesis, the biomimetic synthesis of melanin-like amino acid surfactants with structures similar to that of melanin was conceived. Natural polyphenols with catechol moieties serve as building blocks for hydrophobic moieties. As a proof-of-concept, caffeic acid phenethyl ester was oxidized to o- quinone using periodate resin. Melanin-like amino acid surfactants were synthesized by conjugating amino acids to o -quinones via Michael addition and Schiff base reactions. The structure was confirmed by mass spectrometry. Melanin-like amino acid surfactants have outstanding surface activity with a low critical micelle concentration and excellent capacity for foaming, emulsifying, dispersing, wetting, and solubilizing. Melanin-like amino acid surfactants exhibit low skin irritation, as well as high tolerance to ions and pH. The utilization of polyphenols introduces multifunctionality, affording antioxidant, antibacterial and whitening activities. This study proposes a modular strategy for fabricating new and multifunctional amino acid surfactants that mimic melanin by simply replacing the o -quinone building block. This biomimetic synthesis route is a sustainable process for the green production of amino acid surfactants. This new generation of amino acid surfactants will contribute to meeting the increasing demand for multifunctional surfactants in both academia and industry. [Display omitted] • Novel structure similar with melanin by N-quinonyl linkage. • Biomimetic synthesis route by Michael addition inspired from melanogenesis. • Multifunctionality from natural polyphenols, antioxidant and antibacterial activity. • Modular toolbox by changing the o-quinone building block. • Superior performance on foaming, emulsifying, solubilizing, and dispersing capacity. [ABSTRACT FROM AUTHOR]

(A) Larvae from the crowded treatment (which induced higher melanin pigmentation) lost a significantly lower percentage of total water mass during a period of desiccation than larvae from the solitary treatment (which induced lower melanin pigmentation). (B) However, a path analysis showed that this difference in water loss was not driven by melanin pigmentation but by the crowding treatment itself. Two other measures of desiccation (change in hemolymph osmolality after a period of desiccation and water evaporation rate through the cuticle) did not differ between treatments. Box plot shows median (black line), interquartile range (box), and 5th and 95th percentiles (whiskers) of each treatment. Black diamonds represent the mean of each treatment. Path analysis shows standardized effect sizes. *p = 0.01–0.05, **p = 0.001–0.01, ***p < 0.001. [Display omitted] • Testing the melanin desiccation hypothesis in larvae of the white lined sphinx moth, Hyles lineata, which have plastic melanin pigmentation. • Changes in hemolymph osmolality and evaporation rate of water across the cuticle did not differ between treatments. • Density treatments (rearing larvae solitary or with conspecifics) influenced total water loss, but not via an effect of melanin pigmentation. • Discussion of other factors that influence cuticular water loss including body size and the composition of cuticular hydrocarbons. • Melanin may not play a role in desiccation prevention in lepidopteran larvae which have soft cuticles and are constantly feeding phytophagous insects that get sufficient water from host plants. Water regulation is an important physiological challenge for insects due to their small body sizes and large surface area to volume ratios. Adaptations for decreasing cuticular water loss, the largest avenue of loss, are especially important. The melanin desiccation hypothesis states that melanin molecules in the cuticle may help prevent water loss, thus offering protection from desiccation. This hypothesis has much empirical support in Drosophila species, but remains mostly untested in other taxa, including Lepidoptera. Because melanin has many other important functions in insects, its potential role in desiccation prevention is not always clear. In this study we investigated the role of melanin in desiccation prevention in the white-lined Sphinx moth, Hyles lineata (Lepidoptera, Sphingidae), which shows high plasticity in the degree of melanin pigmentation during the late larval instars. We took advantage of this plasticity and used density treatments to induce a wide range of cuticular melanization; solitary conditions induced low melanin pigmentation while crowded conditions induced high melanin pigmentation. We tested whether more melanic larvae from the crowded treatment were better protected from desiccation in three relevant responses: i) total water loss over a desiccation period, ii) change in hemolymph osmolality over a desiccation period, and iii) evaporation rate of water through the cuticle. We did not find support for the melanin desiccation hypothesis in this species. Although treatment influenced total water loss, this effect did not occur via degree of melanization. Interestingly, this implies that crowding, which was used to induce high melanin phenotypes, may have other physiological effects that influence water regulation. There were no differences between treatments in cuticular evaporative water loss or change in hemolymph osmolality. However, we conclude that osmolality may not sufficiently reflect water loss in this case. This study emphasizes the context dependency of melanin's role in desiccation prevention and the importance of considering how it may vary across taxa. In lepidopteran larvae that are constantly feeding phytophagous insects with soft cuticles, melanin may not be necessary for preventing cuticular water loss. [ABSTRACT FROM AUTHOR]

Avian feather color is a fascinating trait, and the genetic mechanism of duck plumage formation is still in the preliminary stage. In this study, feather color of Liancheng White ducks was analyzed by determination of melanin content and RNA-seq analysis. In this research, 9 ducks from Mallards (n = 3), Liancheng White (n = 3) and Pekin ducks (n = 3) were used by high performance liquid chromatography (HPLC) and Masson-Fontana staining to reveal the difference of feather melanin content. RNA-seq from 11 hair follicle tissues (1- and 8-wk-old) of Liancheng White ducks (n = 5) and Pekin ducks (n = 7) was used to analyze the candidate genes for the feather melanin synthesis, and Immunofluorescence experiment was used to show the protein expression in 6 black- and white-feathered ducks. Pectorale, skin, liver, fat, brain, heart, kidney, lung, spleen of an 8-wk-old black-feathered Mallard were collected for candidate gene expression. The results showed that the contents of feathers, beak, web melanin in Liancheng White ducks were higher than in Pekin ducks (p < 0.05). Melanin within hair follicles was located in the barb ridge and hair matrix of black feather duck, also we found that TYRP1, TYR, SOX10 genes were differentially expressed between Liancheng White and Pekin ducks (p < 0.05), and these genes were mainly expressed showed in duck skin tissues. This study revealed the unique feather color phenotype of Liancheng White duck shedding light on the transcriptome that underlies it. [ABSTRACT FROM AUTHOR]

Non-coplanar polychlorinated biphenyl (PCB) mixture Aroclor 1254 and polybrominated diphenyl ether (PBDE) BDE-47 are known to impede neurogenesis and neuronal development. We previously reported that exposure to PCB and PBDE leads to increased embryonic movement in zebrafish by decreasing dopamine levels. In this study, we studied the connection between the melanin and dopamine synthesis pathways in this context. Both genetic and chemical inhibition of tyrosinase, the rate-limiting enzyme in melanin synthesis, not only led to reduced pigmentation but also inhibit PCB/PBDE-induced embryonic hyperactivity. Furthermore, PCB and PBDE rarely affected tyrosinase expression in the potential pigment cells, suggesting that these compounds reduce dopamine through enzymatic regulation, including a competitive interaction for the substrate tyrosine. Our results provide new insights into the interactions between melanogenesis and dopaminergic neuronal activity, which may contribute to understanding the mechanisms underlying PCB/PBDE toxicity in developing organisms. • Non-coplanar PCB and PBDE impede neurogenesis and neuronal development. • PCB and PBDE enhance embryonic movement in zebrafish by reducing dopamine levels. • Chemical and genetic inhibition of melanin synthesis reduced the PCB/PBDE-induced embryonic hyperactivity. • Our results revealed a link between melanin and dopamine synthesis at the neurobehavioral level. [ABSTRACT FROM AUTHOR]

Melasma is a common skin disease induced by an increase in the content of melanin in the skin, which also causes serious physical and mental harm to patients. In this research, a novel peptide (Nigrocin-OA27) from Odorrana andersonii is shown to exert a whitening effect on C57 mice pigmentation model. The peptide also demonstrated non-toxic and antioxidant capacity, and can significantly reduce melanin content in B16 cells. Topical application effectively delivered Nigrocin-OA27 to skin's epidermal and dermal layers and exhibited significant preventive and whitening effects on the UVB-induced ear pigmentation model in C57 mice. The whitening mechanism of Nigrocin-OA27 may be related to reduced levels of the microphthalmia-associated transcription factor and the key enzyme for melanogenesis-tyrosinase (TYR). Nigrocin-OA27 also inhibited the catalytic activity by adhering to the active core of TYR, thereby reducing melanin formation and deposition. In conclusion, Nigrocin-OA27 may be a potentially effective external agent to treat melasma by inhibiting aberrant skin melanin synthesis. • A novel peptide Nigrocin-OA27 from amphibians exerted a whitening effect. • Nigrocin-OA27 can deliver to the epidermal and dermal layers of the skin. • The whitening mechanism may be related to the reduce of TYR and MITF levels. [ABSTRACT FROM AUTHOR]

A salt-resistant solar-driven interface evaporator was prepared from silk fibroin with a directional channel structure, coated with natural black melanin for solar light harvest and photothermal conversion. This silk fibroin-melanin (SF-melanin) solar-driven evaporator achieved a water evaporation rate of up to 2.49 kg m−2 h−1 under 1 sun beneficial from the intrinsic hydrophilicity of silk fibroin, the directional channel structure, and the high efficiency of solar light harvest and photothermal conversion of natural black melanin. The directional channel structure also facilitates the rapid dissolution of salt crystals back to the native solution, enabling stable performance during the long-term solar-driven desalination process. Moreover, this SF-melanin solar-driven evaporator can totally be degraded in soil since all of its components are bioresource. This high efficient, salt-resistant, biodegradable solar-driven evaporator will further promote the practical application of solar-driven evaporator. [Display omitted] • Silk fibroin aerogel with directional channel structure was obtained by liquid nitrogen-assisted directional freezing method. • Directional silk fibroin-melanin (D-SF-M) evaporator has excellent water-transport capability and broadband light absorption. • D-SF-M evaporator exhibits outstanding solar steam generation and desalination performance. • D-SF-M evaporator is totally biodegradable and environmental friendly. [ABSTRACT FROM AUTHOR]

Melasma is an acquired hypermelanotic condition characterized by the presence of irregular light-to-dark brown macules that primarily manifest on the sun-exposed areas of the skin, particularly the face. The management of melasma poses significant challenges, as it is often recalcitrant to treatment and tends to recur despite successful treatment. In this study, we explored a safe, easy, and effective melasma treatment strategy. A hyaluronic acid (HA)-based microneedle (MN) patch loaded with tranexamic acid (TXA) was designed to deliver the necessary medication for melasma treatment. The MN patch features uniform needles with adequate mechanical strength and effective penetration and solubility in the skin without cytotoxicity. Remarkably, these MNs substantially reduce the thickness of the epidermis of melasma mice, curtail melanin production, and diminish dopachrome tautomerase (DCT) expression. Schematics of the overall procedure for establishing a mouse model of melasma, the composition of the TXA-loaded MN patches prepared via the micromoulding method, and the release of TXA in mouse skin via the dissolution of the TXA-loaded MN patches for melasma treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous studies have shown that all kinin system is constitutively expressed in the normal and inflamed skin, with a potential role in both physiological and pathological processes. However, the understanding regarding the involvement of the kinin system in skin pigmentation and pigmentation disorders remains incomplete. In this context, the present study was designed to determine the role of kinins in the Monobenzone (MBZ)-induced vitiligo-like model. Our findings showed that MBZ induces higher local skin depigmentation in kinin receptors knockout mice (KOB1R, KOB2R and KOB1B2R) than in wild type (WT). Remarkably, lower levels of melanin content and reduced ROS generation were detected in KOB1R and KOB2R mice treated with MBZ. In addition, both KOB1R and KOB2R show increased dermal cell infiltrate in vitiligo-like skin, when compared to WT-MBZ. Additionally, lack of B1R was associated with greater skin accumulation of IL-4, IL-6, and IL-17 by MBZ, while KOB1B2R presented lower levels of TNF and IL-1. Of note, the absence of both kinin B1 and B2 receptors demonstrates a protective effect by preventing the increase in polymorphonuclear and mononuclear cell infiltrations, as well as inflammatory cytokine levels induced by MBZ. In addition, in vitro assays confirm that B1R and B2R agonists increase intracellular melanin synthesis, while bradykinin significantly enhanced extracellular melanin levels and proliferation of B16F10 cells. Our findings highlight that the lack of kinin receptors caused more severe depigmentation in the skin, as well as genetic deletion of both B1/B2 receptors seems to be linked with changes in levels of constitutive melanin levels, suggesting the involvement of kinin system in crucial skin pigmentation pathways. [Display omitted] • Kinin receptors play a role in the regulation of skin pigmentation is described. • Absence of both B1 and B2 kinin receptors reduces total melanin content in skin. • Kinin receptors modulate inflammatory responses in vitiligo lesions, controlling infiltration of inflammatory cells and levels of cytokines. • In melanocytes, both kinin receptors have a potential impact on melanin synthesis, and B2 receptors have a correlation with proliferation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Valorization of the chestnut shell with bioactive pigments was performed. • Optimization of color and bioactive properties of the chestnut shell were carried out through CCD and RSM. • Characterization of bioactive content of chestnut shell. • Melanin pigments in the chestnut shell were characterized. The objective of this study is to find optimum conditions to valorize chestnut shell bioactive compounds with coloring pigments through microwave-assisted extraction. With this aim, response surface methodology with central composite design was used. Microwave power (800 W), extraction time (12 min) and solvent concentration (NaOH: 0.115 mol/L) were determined as the optimum conditions to maximize the responses like color value, total phenolic content and total antioxidant capacity. In the optimized extract (OE), characterization of brown melanin like pigments were assessed by Spectrophotometer, Fourier Transform Infrared Spectrometer and major phenolics were identified as; gallic acid, ellagic acid, protocatechuic acid, catechin, and epicatechin as 0.53, 0.48, 0.46, 0.46, 0.14 mg/g dried weight (dw) by High Performance Liquid Chromatography, respectively. In terms of antibacterial activity, OE inhibited the growth of Staphylococcus aureus. Consequently, chestnut shells were successfully processed into natural coloring agents that were possessing strong brown color properties as well as high bioactive potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three MMS are designed to investigate their corrosion protection performance. • The MMS2/EP offers great corrosion resistance and high elongation at break. • The diffusion coefficient of Cl-, H 2 O and O 2 is simulated by molecular dynamics. • The |Z| 0.01 Hz of the scratched coating is improved by 4 orders of magnitude. Polymer coatings are inherently susceptible to deformation and irreversible damage when they are subjected to external forces during service. Self-healing coatings integrated with exceptional mechanical robustness and corrosion resistance are essential for industrial applications but have been deemed challenging. Here, we present a NIR-triggered self-healing coating by combining a toughness epoxy network with melanin-modified silica (MMS). Moreover, to investigate the impact of pore size and porosity of silica on the corrosion protection performance, three types of various silica particles are selected as building blocks. The melanin-modified fumed silica/epoxy coatings demonstrate superior elongation (275 %), outstanding tensile strength (5.31 MPa) and high toughness (7.37 MJ·m3). Moreover, the introduction of the MMS can not only improve the anticorrosion performance (|Z| 0.01 Hz value of 1.24 × 1010 Ω·cm2) but also realize fast photo-thermal repair (60 s). Our strategy furnishes a universal layout prototype for the manufacture of robust self-healing coatings with a scalable and cost-effective preparation method. [ABSTRACT FROM AUTHOR]

Visible light triggers free radical production in alive and intact Drosophila melanogaster. We exposed fruit flies to red (613–631 nm), green (515–535 nm), and blue (455–475 nm) light while we monitored changes in unpaired electron content with an electron spin resonance spectrometer (ESR/EPR). The immediate response to light is a rapid increase in spin content lasting approximately 10 s followed by a slower, linear increase for approximately 170 s. When the light is turned off, the spin population promptly decays with a similar time course, though never fully returning to baseline. The magnitude and time course of the spin production depends on the wavelength of the light. Initially, we surmised that eumelanin might be responsible for the spin change because of its documented ability for visible light absorption and its highly stable free radical content. To explore this, we utilized different fruit fly strains with varying eumelanin content and clarified the relation of melanin types with the spin response. Our findings revealed that flies with darker cuticle have at least three-fold more unpaired electrons than flies with yellow cuticle. However, to our surprise, the increase in unpaired electron population by light was not drastically different amongst the genotypes. This suggests that light-induced free radical production may not exclusively rely on the presence of black melanin, but may instead be dependent on light effects on quinone-based cuticular polymers. • Light exposure increases the population of unpaired electrons in fruit flies. • Flies produce more spin when exposed to a short wavelength of visible light. • The ESR spectrum of flies depends on their melanin content. • Lack of eumelanin surprisingly coincides with a strong response to light in ESR. [ABSTRACT FROM AUTHOR]

Streptomycin (STR) is an aminoglycoside antibiotic with a broad-spectrum of activity and ototoxic potential. The mechanism of STR-induced inner ear damage has not been fully elucidated. It was previously found that STR binds to melanin, which may result in the accumulation of the drug in melanin-containing tissues. Melanin pigment is present in various parts of the inner ear, including the cochlea and vestibular organ. The present study aimed to assess if streptomycin generates oxidative stress and affects melanogenesis in normal human melanocytes. Moreover the variation of free radical concentration in STR-treated melanocytes was examined by electron paramagnetic resonance spectroscopy (EPR). We found that STR decreases cell metabolic activity and reduces melanin content. The observed changes in the activity of antioxidant enzymes activity in HEMn-DPs treated with streptomycin may suggest that the drug affects redox homeostasis in melanocytes. In this work EPR study expanded knowledge about free radicals in interactions of STR and melanin in melanocytes. The results may help elucidate the mechanisms of STR toxicity on pigment cells, including melanin-producing cells in the inner ear. This is important because understanding the mechanism of STR-induced ototoxicity would be helpful in developing new therapeutic strategies to protect patients' hearing. • Streptomycin decreases metabolic activity and reduces melanin in melanocytes. • Streptomycin affects antioxidant enzymes in melanocytes. • Free radicals participate in streptomycin interactions with pigmented cells. • Melanin may protect pigment cells from adverse effects of streptomycin. [ABSTRACT FROM AUTHOR]

This study compares the skin structures of Rana kukunoris with two different skin colors living in the same area of Haibei in the Northeastern Qinghai-Tibet Plateau. The skin thickness of the khaki R. kukunoris was significantly greater than that of the brown R. kukunoris (P < 0.01), and significantly more mucous and granular glands were present on the dorsal skin of the khaki frog (P < 0.05). Meanwhile, the melanocytes on the dorsal skin of the brown frog were significantly larger than those on the khaki one (P < 0.05). Morphological changes in the expansion and aggregation of melanocytes seemed to deepen the skin color of R. kukunoris. Moreover, transcriptome sequencing identified tyrosine metabolism, melanogenesis, and riboflavin metabolism as the main pathways involved in melanin formation and metabolism in brown R. kukunoris. TYR, MC1R was upregulated as the skin color of R. kukunoris was deepened and contributed to melanin production and metabolism. In contrast, the khaki frog had significantly more upregulated genes and metabolic pathways related to autoimmunity. The khaki frog appeared to defend against ultraviolet (UV) radiation-induced damage by secreting mucus and small molecular peptides, whereas the brown frog protected itself by distributing a large amount of melanin. Hence, the different skin colors of R. kukunoris might represent different adaptation strategies for survival in the intense UV radiation environment of the Qinghai-Tibet Plateau. Figure. Individuals, Paraffin sections, Comparison of the morphological characteristics and the differentially expressed genes of R. kukunoris with different skin colors. [Display omitted] • The skin thickness of the khaki Rana kukunoris is greater than brown one • TYR and MC1R have different expression • Different skin colors are adaptation strategies to survive intense UV radiation [ABSTRACT FROM AUTHOR]

Solar-driven interface evaporation has emerged as an attractive technology for addressing the pressing issue of water scarcity. Herein, from the perspective of utilizing and managing ocean resources, we have developed a comprehensive evaporator based on ocean biomass for efficient solar-driven interfacial evaporation, aiming to sustainably harness marine resources. The construction of a biomass-based evaporator was achieved using three-dimensional melanin nanoparticles (MNPs)@carboxymethyl chitosan (CMCS)/polydimethylsiloxane (PDMS) porous sponge, which exhibits highly hydrophilic and porous properties. In this study, MNPs functioned as the photothermal material and the CMCS-hydrophilic modified PDMS sponge was utilized as the supportive material. Owing to its outstanding photothermal conversion capability and ingeniously designed columnar shape with cold evaporation surface, the MCP sponge-based evaporator achieves a water evaporation rate of 2.04 kg·m−2·h−1 and an evaporation efficiency of 85% under 1sun illumination. In addition, the MCP sponge-based evaporator exhibits an outstanding desalination performance (93% salt rejection) and purification efficiency for dyes with natural sunlight. This groundbreaking study presents an innovative method by utilizing marine biomass-derived CMCS and MNPs as raw materials to construct a high-performance solar-driven interface evaporator, thereby tackling clean water generation and promoting the sustainability of marine ecosystems. [Display omitted] • A comprehensive ocean biomass-based evaporator was developed. • The evaporation rate is 2.04 kg·m−2·h−1, with an efficiency of 85% under 1sun. • Evaporator has excellent purification for inorganic ions and wastewater with organic dyes. • This work can promote the sustainability of marine ecosystems. [ABSTRACT FROM AUTHOR]

EPR spectroscopy is a technique that provides direct information about free radicals in biological systems. So far, X-band EPR was seldomly used for in vivo studies as the small resonator size and high power used to detect EPR signals were unsuitable for living organisms. Here, we report new solutions which lift some limitations and make X-band EPR suitable for an in vivo detection of free radicals in zebrafish - a small laboratory animal that is often used as a model for various studies related to free radicals. We designed specially-shaped glass and quartz capillaries to ensure the zebrafish's safety during the experiments. The optimal EPR spectrometer parameters, safe for zebrafish embryos and sufficient to obtain EPR spectrum, were 4 scans by 20s, 100G sweep, and 0.8 mW power. Combining the specially-shaped capillary with a multi-harmonic analyzer for the EPR spectrometer allowed increasing the time up to 16 scans by 11s and lowering the power to 0.25 mW. As a proof of principle, we demonstrate the detection of melanin radicals and the 5-DSA spin probe in zebrafish larvae. As fish survive the EPR scans, the possibility of performing multiple measurements of free radicals in living zebrafish offers new tools for studies aiming to understand redox biology and membrane-dependent functions in both health and disease. [Display omitted] • Short exposure to low power X band EPR radiation is safe for zebrafish. • Specially shaped capillary ensures proper positioning of the sample and tuning of EPR. • Glass and quartz capillaries are both effective for the measurement of free radicals. • Melanin radical could be observed in vivo in zebrafish larvae with X band EPR. • Membrane fluidity changes could be observed in vivo in zebrafish larvae with X band EPR. [ABSTRACT FROM AUTHOR]

Background: Valid biomarkers of fruit and vegetable (FV) intake are needed for field-based nutrition research.Objectives: To examine criterion-related validity of pressure-mediated reflection spectroscopy as a proxy measure of FV intake, using plasma carotenoids and self-reported FV and carotenoid intake as primary and secondary criterion measures, respectively.Methods: Healthy adults 18-65 y of age, self-identifying as African American/black (n = 61), Asian (n = 53), white (n = 70), or Hispanic (n = 29), in North Carolina and Minnesota were recruited. Skin carotenoids were assessed via pressure-mediated reflection spectroscopy (Veggie Meter), skin melanin via spectrophotometer, and total plasma carotenoid concentration by HPLC-photodiode array detection. Self-reported carotenoid and FV intake was assessed using a semiquantitative FFQ. Relations between skin carotenoids, plasma carotenoids, FV, and carotenoid intake, with differences by race or ethnicity, age, sex, weight status, cholesterol, and melanin index, were examined by bivariate correlations and adjusted multivariate linear regressions.Results: The overall unadjusted correlation between skin and total plasma carotenoids was r = 0.71 and ranged from 0.64 (non-Hispanic black) to 0.80 (Hispanic). Correlations between skin carotenoids and self-reported FV intake ranged from 0.24 (non-Hispanic black) to 0.53 (non-Hispanic white), with an overall correlation of r = 0.35. In models adjusted for age, sex, racial or ethnic group, and BMI, skin carotenoids were associated with plasma carotenoids (R2 = 0.55), FV (R2 = 0.17), and carotenoid intake (R2 = 0.20). For both plasma carotenoid and FV measures, associations with skin carotenoids did not vary by race, but these relations did differ by skin melanin-those with lower melanin had a lower correlation between skin and plasma carotenoids.Conclusions: Reflection spectroscopy-assessed skin carotenoids may be a reasonable alternative to measurement of plasma carotenoids, a biomarker used to approximate FV intake. [ABSTRACT FROM AUTHOR]

• P. oleracea diminished the α-MSH-induced tyrosinase activity in a concentration-dependent manner. • P. oleracea concentration-dependently mitigated the α-MSH-induced extracellular melanin content. • Intra and extracellular melanin contents were suppressed following the P. oleracea treatment in a concentration-dependent manner. • P. oleracea mitigated the levels of Trp-1, Trp-2, and MITF expression levels following the α-MSH-induced stimulation. Portulaca oleracea (P. oleracea) has been used in folk medicine for treatment of diverse disorders for centuries. In the present study, we aimed to evaluate the anti-melanogenic properties of P. oleracea ethanolic extract on B16F1 murine melanoma cell line. The effect of different concentrations of P. oleracea and arbutin as positive control were investigated on the levels of cell viability, cellular tyrosinase, extracellular and intracellular melanin content as well as tyrosinase, tyrosinase related protein (Trp)-1, Trp-2, and microphthalmia-associated transcription factor (MITF) expression levels using real time-PCR, in B16F1 murine melanoma cell line. All different concentrations of P. oleracea (1–100 μg/ml) and arbutin (10 μM) did not significantly change the viability of B16F1 cells. Our results showed that α−melanocyte-stimulating hormones (α-MSH) (100 nM) significantly increased the levels of tyrosinase activity, extracellular, and intracellular melanin content as well as tyrosinase, Trp-1, Trp-2, and MITF expression levels in B16F1 cells. In contrast, arbutin (10 μM) significantly suppressed these changes following the α-MSH stimulation in B16F1 cells. Moreover, P. oleracea (1–100 μg/ml) remarkably mitigated the levels of tyrosinase activity, extracellular and intracellular melanin content as well as tyrosinase, Trp-1, Trp-2, and MITF expression levels following the α-MSH stimulation in B16F1 cells in a concentration-dependent manner. The plant possessed anti-melanogenic effects through alleviating tyrosinase, TRP-1, TRP-2, and MITF expression levels as well as melanin content and it may be a promising candidate for pigmentation disorders. However, further clinical investigations are required to confirm our results. [ABSTRACT FROM AUTHOR]

Black fungi (Auricularia auricula) was known as one of the major mushrooms grown and cultivated all over the world, especially northeast Asia. It has been proved that black fungi had tremendous biological functions, and thus was being remarked to be a potential ingredient for the functional food. This review comprises a comprehensive research for the isolation and characterization of bioactive components in black fungi and their potent physiological activities. Meanwhile, chemical and metabolic methodologies are introduced to clarify the specified mechanism and future challenges. Integrated research results showed that black fungi contain some bioactive components such as polysaccharide, melanin and phenolic. According to origin and isolation method, the structural features of polysaccharide and melanin were significantly different. Health benefits such as antioxidant, hypoglycemic, antitumor and immunostimulation could be exerted with black fungi components and their derivatives. Besides, biological activity and physicochemical property of black fungi enabled the application in the drug delivery and food production. Detailed mechanisms confirmed that oxidative damage removal, immune signal transduction and gut microbiota enhancement supports the promising functionality. However, present research of black fungi still demands the more efficient extraction and purification including subcritical water, ohmic, high hydrostatic pressure (HHP) and two-phase partitioning. Challenges to some health benefits such as gut microbiota-immune, dosage suitable for clinical practice and especially structure-function relationship should also be worthwhile to increase the total functional value of black fungi. • Polysaccharide, melanin and polyphenol are identified as black fungi biomolecules. • ROS removal by black fungi is a key governor of whole health benefits. • Black fungi provoke the immune-gut microbiota axis for physiological functions. • Physicochemical property of black fungi is applied for food and drug delivery. [ABSTRACT FROM AUTHOR]

This study examined microclimate changes to the skin as a result of pressure over a 1 h period. The results were compared to skin parameter results following brief consecutive off-loading of pressure-prone areas. A descriptive-correlational pilot study was undertaken. A convenience sample of 41 healthy adults aged 18–60 years was recruited. Participants engaged in four 1 h data collection sessions. The sessions were conducted in both semi-recumbent and supine positions. Measures of erythema, melanin, stratum corneum hydration, and skin temperature were taken at pressure-prone areas at baseline and after 1 h in an uninterrupted method (continuous pressure-loading) and every 10 min in an interrupted method (brief off-loading). The Corneometer and Mexameter (Courage + Khazaka Electronics GMbH, 2013) and Exergen DermaTemp DT-1001 RS Infrared Thermographic Scanner (Exergen Corporation, 2008) provided a digital appraisal of skin parameters. Intraclass correlation coefficients (ICC) were calculated to indicate test-retest reliability and absolute agreement of results between the two methods. Strong agreement between the interrupted and uninterrupted method was observed with ICCs ranging from 0.72 to 0.99 (supine) and 0.62–0.99 (semi-recumbent). Endpoint measures tended to be higher compared to baseline measures for all skin parameters. Differences in skin parameters results by anatomical location were evident particularly for erythema and stratum corneum hydration; the elbows and heels yielded lower scores compared to the sacrum. Erythema had the most variation across methods. The supine and semi-recumbent positions had negligible effect on measured skin parameters. Minimal variation between skin parameter results indicates that brief off-loading in the interrupted method did not significantly change the outcomes; minor shifts in positioning do not alter changes to the skin from pressure. Skin parameters varied by anatomical location and changed over a 1 h period of pressure-loading. Biophysical techniques may be able to assist accurate assessment of skin microclimate and skin colour. As brief off-loading (interruptions) to enable skin parameter measurement does not alter skin readings, researchers can proceed with some confidence regarding the use of this protocol in future studies assessing skin parameters. This study data provides a library of cutaneous changes at pressure-prone areas of healthy adults and is expected to inform innovative approaches to pressure injury risk assessment. • Biophysical techniques may be able to assist in the evaluation of skin microclimate and skin colour at pressure prone areas. • The data captured in this study provide a library of cutaneous changes at pressure-prone areas of healthy adults. • Brief off-loading to enable skin parameter measurement at 10 minute increments over 1 hour does not appear to alter skin readings. • Researchers can proceed with some confidence regarding the use of this protocol in future studies assessing skin parameters. • The study findings are expected to inform innovative approaches to pressure injury risk assessment. [ABSTRACT FROM AUTHOR]