Read by QxMD icon Read

Melanin degradation

María Elisa Pavan, Esmeralda Solar Venero, Diego E Egoburo, Esteban E Pavan, Nancy I López, M Julia Pettinari
The environmental strain Aeromonas salmonicida subsp. pectinolytica 34melT produces abundant melanin through the homogentisate pathway in several culture media, but unexpectedly not when grown in a medium containing glycerol. Using this observation as a starting point, this study investigated the underlying causes of the inhibition of melanin synthesis by glycerol, to shed light on factors that affect melanin production in this microorganism. The effect of different carbon sources on melanin formation was related to the degree of oxidation of their C atoms, as the more reduced substrates delayed melanization more than the more oxidized ones, although only glycerol completely abolished melanin production...
December 11, 2018: Applied Microbiology and Biotechnology
Katharina Fürst, Marc Steder, Stella Logotheti, Alessandro Angerilli, Alf Spitschak, Stephan Marquardt, Toni Schumacher, David Engelmann, Ottmar Herchenröder, Ralph A W Rupp, Brigitte M Pützer
Melanoma is an aggressive cancer with poor prognosis, requiring personalized management of advanced stages and establishment of molecular markers. Melanomas derive from melanocytes, which specifically express tyrosinase, the rate-limiting enzyme of melanin-synthesis. We demonstrate that melanomas with high levels of DNp73, a cancer-specific variant of the p53 family member p73 and driver of melanoma progression show, in contrast to their less-aggressive low-DNp73 counterparts, hypopigmentation in vivo. Mechanistically, reduced melanin-synthesis is mediated by a DNp73-activated IGF1R/PI3K/AKT axis leading to tyrosinase ER-arrest and proteasomal degradation...
November 13, 2018: Cancer Letters
Abha Sharma, Kavish Kumar Jain, Arti Jain, Mazahir Kidwai, R C Kuhad
Laccases are multicopper enzymes present in plants, fungi, bacteria, and insects, which catalyze oxidation reactions together with four electron reduction of oxygen to water. Plant, bacterial, and insect laccases have a polymerizing role in nature, implicated in biosynthesis of lignin, melanin formation, and cuticle hardening, respectively. On the other hand, fungal laccases carry out both polymerizing (melanin synthesis and fruit body formation) as well as depolymerizing roles (lignin degradation). This bifunctionality of fungal laccases can be attributed to the presence of multiple isoforms within the same as well as different genus and species...
November 8, 2018: Applied Microbiology and Biotechnology
Taek-In Oh, Hye-Jeong Jung, Yoon-Mi Lee, Sujin Lee, Geon-Hee Kim, Sang-Yeon Kan, Hyeji Kang, Taerim Oh, Hyun Myung Ko, Keun-Chang Kwak, Ji-Hong Lim
Zerumbone (ZER), an active constituent of the Zingiberaceae family, has been shown to exhibit several biological activities, such as anti-inflammatory, anti-allergic, anti-microbial, and anti-cancer; however, it has not been studied for anti-melanogenic properties. In the present study, we demonstrate that ZER and Zingiber officinale (ZO) extract significantly attenuate melanin accumulation in α-melanocyte-stimulating hormone (α-MSH)-stimulated mouse melanogenic B16F10 cells. Further, to elucidate the molecular mechanism by which ZER suppresses melanin accumulation, we analyzed the expression of melanogenesis-associated transcription factor, microphthalmia-associated transcription factor (MITF), and its target genes, such as tyrosinase , tyrosinase-related protein 1 ( TYRP1 ), and tyrosinase-related protein 2 ( TYRP2 ), in B16F10 cells that are stimulated by α-MSH...
October 13, 2018: International Journal of Molecular Sciences
Mark F Kavlick
A hybrid absolute/relative qPCR assay which provides information regarding the condition of mitochondrial DNA (mtDNA) in a DNA sample is described. MtDNA concentration (copy number/μL) is determined via absolute quantification using a standard curve of a synthetic duplex DNA previously described (Kavlick et al., 2011). The state of mtDNA degradation is determined via the relative quantification of a mtDNA target found within the 16 s rRNA gene which is 3× longer than that of the short target in the former duplex assay, using the delta, delta Ct (ΔΔCt) method...
September 25, 2018: Mitochondrion
Jordan M Blacktop, Barbara A Sorg
We previously reported that a small, circumscribed region of the lateral hypothalamus, the anterior dorsal region (LHAad), stains heavily for PNNs and dense extracellular matrix (PNNs/ECM) with Wisteria floribunda agglutinin (WFA), and critically contributes to the acquisition of cocaine-induced conditioned place preference and cocaine self-administration. Here we tested the role of LHAad PNNs/ECM in cue-induced reinstatement in cocaine self-administering (SA) rats and identified how it is embedded in the circuitry of motivated behavior and drug reward...
September 11, 2018: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Anita J Grosvenor, Santanu Deb-Choudhury, Paul G Middlewood, Ancy Thomas, Erin Lee, James A Vernon, Joy L Woods, Cheryl Taylor, Fraser I Bell, Stefan Clerens
OBJECTIVE: To understand the structural and chemical effects of cosmetic peroxide bleaching on human hair. Methods Human hair was progressively bleached using alkaline peroxide-persulfate treatment. Proteins lost through leaching were examined using amino acid analysis and mass spectrometric sequencing. Fibre damage was assessed using transmission electron microscopy, amino acid analysis, and redox proteomics. RESULTS: Protein loss through leaching increased with bleaching severity...
September 19, 2018: International Journal of Cosmetic Science
Md Badrul Alam, Arif Ahmed, Md Abdul Motin, Sunghwan Kim, Sang-Han Lee
Medicinal plants have been used to treat diseases from time immemorial. We aimed to examine the efficacy of the ethyl acetate fraction of Nymphaea nouchali flower extract (NNFE) against melanogenesis process, and the underlying mechanisms in vitro and in vivo. Paper spray ionisation mass spectroscopy and (+) mode electrospray ionisation revealed the presence of seven flavonoids, two spermidine alkaloids, 3,4,8,9,10-pentahydroxy-dibenzo[b,d]pyran-6-one, and shoyuflavone C in NNFE. NNFE (100 µg/mL) significantly inhibited the monophenolase and diphenolase activities of mushroom tyrosinase at 94...
September 17, 2018: Scientific Reports
Lijun Sun, Lei Hu, Ping Zhang, Huijin Li, Jingying Sun, Haifang Wang, Xin Xie, Jun Hu
The functionally specialized melanosome is a membrane-enclosed lysosome-related organelle, which coexists with lysosomes in melanocytes. Pre-melanosomal protein (PMEL) initiates pre-melanosome morphogenesis and is the only cell-specific pigment protein required for the formation of fibrils on which melanin is deposited in melanosomes. But the effects of PMEL on melanin synthesis and lysosome activity remain unclear. In the study, PMEL was silenced in human epidermal melanocytes by siRNA transfection. Compared to the non-treated group, melanin content in the transfected cells was greatly reduced...
September 18, 2018: Biochemical and Biophysical Research Communications
N Joly-Tonetti, J I D Wibawa, M Bell, D J Tobin
BACKGROUND: Melanin is synthesized by melanocytes in the basal layer of the epidermis. When transferred to surrounding keratinocytes melanin is the key ultraviolet radiation-protective biopolymer responsible for skin pigmentation. Most melanin is observable in the proliferative basal layer of the epidermis and only sparsely distributed in the stratifying/differentiating epidermis. The latter has been explained as 'melanin degradation' in suprabasal layers. OBJECTIVES: To re-evaluate the currently accepted basis for melanin distribution in human epidermis and to discover whether this pattern is altered after a regenerative stimulus...
November 2018: British Journal of Dermatology
Pan Soo Kim, Ji Hyun Shin, Doo Sin Jo, Dong Woon Shin, Dong-Hwa Choi, Woo Jung Kim, Kyuhee Park, Jin Kyu Kim, Chul Gue Joo, Jong Suk Lee, Yongmun Choi, Yong Won Shin, Joong Jin Shin, Hong Bae Jeon, Jin-Ho Seo, Dong-Hyung Cho
Skin pigmentation involves multiple processes, including melanin synthesis, transport, and melanosome release. Melanin content determines skin color and protects against UV radiation-induced damage. Autophagy is a cooperative process between autophagosomes and lysosomes that degrades cellular components and organelles. In the present study, B16F1 cells were treated with Rhizoma Arisaematis extract (RA) and assessed for pigmentation and autophagy regulation. RA treatment suppressed the α-MSH-stimulated increase of melanogenesis and down-regulated the expression of tyrosinase and TRP1 proteins in B16F1 cells...
September 3, 2018: Biochemical and Biophysical Research Communications
Mohammed Shariful Azam, Misung Kwon, Jinkyung Choi, Hyeung-Rak Kim
Hyperpigmentation disorders of the skin adversely influence the quality of life. We previously demonstrated the hypopigmenting properties of the ethanolic extract from Sargassum serratifolium and identified sargaquinoic acid (SQA) as an active component. The current study aims to investigate the hypopigmenting action of SQA in α-melanocyte stimulating hormone (α-MSH)-stimulated B16F10 cells. SQA attenuated cellular melanin synthesis by inhibiting the expression of the melanogenic enzymes, including tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and TRP2...
August 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Sally M Yacout, Kelsey L McIlwain, Shama P Mirza, Elizabeth R Gaillard
With increasing age, there is an observable loss of melanin in retinal pigment epithelial (RPE) cells. It is possible that degradation of the pigment contributes to the pathogenesis of retinal disease, as the cellular antioxidant material is depleted. Functionally, intact melanin maintains protective qualities, while oxidative degradation of melanin promotes reactive oxygen species (ROS) generation and formation of metabolic byproducts, such as melanolipofuscin. Understanding the structural and functional changes to RPE melanin with increasing age may contribute to a better understanding of disease progression and risk factors for conditions such as age-related macular degeneration (AMD)...
May 12, 2018: Photochemistry and Photobiology
Ji Hoon Ha, Yoon Ju Jeong, Song Hua Xuan, Jae-Young Lee, Jino Park, Soo Nam Park
BACKGROUND: Microphthalmia-associated transcription factor (MITF) is regulated by expression and/or degradation pathway, controlling to the expression of melanogenic enzymes for melanin synthesis. Methyl-2-acetylamino-3-(4-hydroxyl-3,5-dimethoxybenzoylthio)propanoate (MAHDP) is reported to anti-melanogenesis effect but its mechanism remain unclear. OBJECTIVE: To investigate the effects of MAHDP on melanogenesis and elucidate its mechanism. METHODS: Tyrosinase activity, melanogenic proteins and gene expression levels were measured with MAHDP treatment in B16F1 cells, human melanocytes, reconstructed skin and clinical trial...
April 22, 2018: Journal of Dermatological Science
Yushi Katsuyama, Norihisa Taira, Masato Yoshioka, Yuri Okano, Hitoshi Masaki
The formation of skin pigmentation requires multiple steps, namely the activation of melanocytes, the synthesis of melanin, the transport of melanosomes to the tips of melanocyte dendrites and the transfer of melanosomes from melanocytes to surrounding keratinocytes. Recently, we reported that melanosomes accumulate in melanocytes when melanosome transport is disrupted and that they are then degraded by the autophagy system. In this study, we examined whether 3-O-glyceryl-2-O-hexyl ascorbate (VC-HG) suppresses melanogenesis through the activation of autophagy since VC-HG interferes with melanosome transport through the down-regulated expression of MyosinVa and Kinesin...
2018: Biological & Pharmaceutical Bulletin
Dániel G Knapp, Julianna B Németh, Kerrie Barry, Matthieu Hainaut, Bernard Henrissat, Jenifer Johnson, Alan Kuo, Joanne Hui Ping Lim, Anna Lipzen, Matt Nolan, Robin A Ohm, László Tamás, Igor V Grigoriev, Joseph W Spatafora, László G Nagy, Gábor M Kovács
Dark septate endophytes (DSE) are a form-group of root endophytic fungi with elusive functions. Here, the genomes of two common DSE of semiarid areas, Cadophora sp. and Periconia macrospinosa were sequenced and analyzed with another 32 ascomycetes of different lifestyles. Cadophora sp. (Helotiales) and P. macrospinosa (Pleosporales) have genomes of 70.46 Mb and 54.99 Mb with 22,766 and 18,750 gene models, respectively. The majority of DSE-specific protein clusters lack functional annotation with no similarity to characterized proteins, implying that they have evolved unique genetic innovations...
April 20, 2018: Scientific Reports
R Abdayem, M Haftek
The skin acts as an interface between the body and its surrounding environment. The epidermis, the surface layer of the skin, is chiefly responsible for this interactive protective function. The epidermal barrier may be subdivided into three defensive systems: the photoprotective barrier, the immune barrier, and the physical and chemical barrier of the stratum corneum or horny layer. To protect against harmful ultraviolet radiation, the epidermis has absorption factors such as melanin, produced by melanocytes, and urocanic acid, which is a degradation product of filaggrin...
April 2018: Annales de Dermatologie et de Vénéréologie
Wen-Juan Yi, Meng-Yun Su, Ying Shi, Shan Jiang, Shi-Zheng Xu, Tie-Chi Lei
Melanosomes are membrane-bound intracellular organelles that are uniquely generated by melanocytes (MCs) in the basal layer of human epidermis. Highly pigmented mature melanosomes are transferred from MCs to keratinocytes (KCs), and then positioned in the supra-nuclear region to ensure protection against ultraviolet radiation (UVR). However, the molecular mechanism underlying melanosome (or melanin pigment) transfer remains enigmatic. Emerging evidence shows that exo-/endo-cytosis of the melanosome core (termed melanocore) has been considered as the main transfer manner between MCs and KCs...
2018: Cell Cycle
Rita Kiss, Katalin Szabó, Rudolf Gesztelyi, Sándor Somodi, Péter Kovács, Zoltán Szabó, József Németh, Dániel Priksz, Andrea Kurucz, Béla Juhász, Zoltán Szilvássy
In developed, developing and low-income countries alike, type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases, the severity of which is substantially a consequence of multiple organ complications that occur due to long-term progression of the disease before diagnosis and treatment. Despite enormous investment into the characterization of the disease, its long-term management remains problematic, with those afflicted enduring significant degradation in quality-of-life. Current research efforts into the etiology and pathogenesis of T2DM, are focused on defining aberrations in cellular physiology that result in development of insulin resistance and strategies for increasing insulin sensitivity, along with downstream effects on T2DM pathogenesis...
March 8, 2018: International Journal of Molecular Sciences
Chao Niu, Li Yin, Haji Akber Aisa
The extracts of Ficuscarica L. and Psoralen corylifolia L. are traditional Uygur medicines for the treatment of vitiligo, and its active ingredients furocoumarins, were are found to be the most effective agents against this skin disorder nowadays. Therefore, a series of novel easter derivatives ( 8a - 8p ) of furocoumarin were designed and synthesized based on our previous research to improve this activity in the present study. The synthesized derivatives were biologically evaluated for melanin synthesis in murine B16 cells and the SAR (structure-activity relationship) was summarized...
March 6, 2018: International Journal of Molecular Sciences
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"