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Topic: Melanogenesis

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In the News (Thu 18 Jul 19)

  Melanogenesis - Wikipedia, the free encyclopedia
Melanogenesis is the production of the pigment melanin, responsible for skin colour.
It is triggered by the damaging effect of ultraviolet rays.
The IFPCS presidential lecture: a chemist's view of melanogenesis
en.wikipedia.org /wiki/Melanogenesis   (121 words)

 Study 4 Melanin 95
Besides, it should be stressed that the various melanogenesis in vitro and in vivo are fluctuating chemical systems, in the sense predicted and studied by Piccardi (Florence) sensitive to variables of a terrestrial, solar and cosmic nature.
The melanogenesis of the tuberculosis bacillus is unclear as is that of the Mycobacerium nigrum.
The dopasemiquinone which is formed in the first stages of melanogenesis by oxidation of the DOPA also provides the explanation of the formation of different tricochromes (pheochromes) (1, d) from the various cysteinyldopas.
www.tightrope.it /nicolaus/melanin95.htm   (10653 words)

 Melanocyte article - Melanocyte epidermis melanogenesis melanin skin eyes hair Caucasian ultraviolet - What-Means.com   (Site not responding. Last check: 2007-10-26)
Melanocytes are cells located in the bottom layer of the skin's epidermis.
With a process called melanogenesis, they produce melanin, a pigment in the skin, eyes, and hair.
In Caucasian people, melanocytes are triggered by ultraviolet rays, thus they have to be in the sunlight to tan.
www.what-means.com /encyclopedia/Melanocyte   (212 words)

 US Patent 5698184 - Compositions and methods for sun tanning and protection
Overall, ultraviolet-induced melanogenesis may be one part of a eukaryotic SOS response to damaging ultraviolet irradiation that has evolved over time to provide a protective tan in skin at risk of further injury from sun exposure.
Methods that increase melanogenesis and thus skin melanin have been developed but they typically do not increase the reddish color of skin that is part of the natural tanning process.
According to the invention, the formulations are administered to the skin of a mammal in an amount sufficient to accelerate melanogenesis, typically in an amount sufficient such that the accelerated melanogenesis results in prolonged and natural-appearing increased pigmentation of the skin.
www.suntanscience.com /uspatent5698184.html   (5273 words)

 Ethan Frome   (Site not responding. Last check: 2007-10-26)
It is not yet clear if the melanogenesis can proceed with the intervention of different melanogens like DHICA acid and the nature of the process in animals of different classes and orders, or the nature of the melanogenesis in differing biological sources and whether there is a difference between physiological and pathological melanogenesis are unstudied.
The study of melanogenesis or better the special process which happens in the ink sack of the Sepia officinalis is, in general, also considered valid for what happens in the melanocytes of mammals but studies on it are few.
The hydrated quinonic forms appear in the course of the melanogenesis from the first oligomers of DHI where with mass spectrometry it is possible to show the increase of mass of 16 m/z (606, 753, 900, 1047 m/z).
www.tightrope.it /nicolaus/ponta.htm   (5672 words)

 Abstracts Melanocitos
The involvement of the multipotent PPO in melanogenesis and its relationship with the SDS-activated form and with the alternative functions proposed for multicopper oxidases in other microorganisms are discussed.
Expression was determined by reverse transcriptase-competitive multiplex polymerase chain reaction of (i) melanogenesis enzyme transcripts and the "housekeeping" gene glyceraldehyde-3-phosphate dchydrogenase, and (ii) two internar standards consisting of mutated melanogenesis enzyme cDNA and mutated gene glyceraldehyde-3-phosphate dehydrogenase cDNA.
Tyrosinase, the rate-limiting enzyme in mammalian melanogenesis, is a copper-containing transmembrane glycoprotein.
www.um.es /bbmbi/GruposInvest/Melano/mel-abstracts.htm   (14513 words)

 Wildberry Extract
However, recent studies have shown that mammalian melanogenesis is not regulated solely by tyrosinase at the enzymatic level, and additional melanogenic factors have been identified which can modulate pigmentation in either a positive or negative fashion.
Lastly, melanogenesis is regulated at the subcellular level where the synthesis and expression of various melanogenic enzymes and inhibitors play a critical role.
There are chemical sun screens that absorb UV light, antioxidants that inhibit several oxidation steps during melanogenesis, reducing agents that reduce dopaquinone back to DOPA, indole-blocking factors which interrupt intermediates in melanin biosynthesis, and inhibitors for the enzymes tyrosinase dopachrome tautomerase and peroxidases that are involved in melanogenesis.
www.naturalskincare.com /SilSpray.htm   (2231 words)

 [No title]   (Site not responding. Last check: 2007-10-26)
Melanogenesis occurs within the melanosome, and the melanin is later distributed to keratinocytes via the melanocyte dendrites.
The key enzyme in melanogenesis is tyrosinase, which initiates a cascade of reactions which convert tyrosine to the biopolymer melanin.
In spite of the fact that the chemical and enzymatic basis of melanogenesis is well-documented, its regulation at the cellular level is only partially understood.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=99/04752.990408&ELEMENT_SET=DECL   (8574 words)

 Down-regulation of Melanogenesis by Phospholipase D2 through Ubiquitin Proteasome-mediated Degradation of Tyrosinase -- ...
involvement of PLD in the TPA-induced inhibition of melanogenesis.
of melanogenesis is inhibited mainly by PLD2 and, to a lesser
of melanogenesis is mediated by PLD2 in a physiological manner.
www.jbc.org /cgi/content/full/279/26/27774   (4359 words)

 Tumor necrosis factor alpha-mediated inhibition of melanogenesis is dependent on nuclear factor kappa B activation   (Site not responding. Last check: 2007-10-26)
Tumor necrosis factor alpha-mediated inhibition of melanogenesis is dependent on nuclear factor kappa B activation
Melanogenesis is a physiological process resulting in the synthesis of melanin pigments which play a crucial protective role against skin photocarcinogenesis.
In vivo, solar ultraviolet light triggers the secretion of numerous keratinocyte-derived factors that are implicated in the regulation of melanogenesis.
www.nature.com /cgi-taf/DynaPage.taf?file=/onc/journal/v18/n8/abs/1202446a.html   (314 words)

 XVIth IPCC Summaries
The Workshop on extracutaneous melanin, melanocytes and melanogenesis began with an overview by RU Peter who pointed out that not all pigment cells in mammals derive from the neural crest.
He cautioned, however, that in the case of melanogenesis in vitro and in vivo enzymatic activities might not necessarily corrrespond, particularly since melanin intermediates are often a) unstable in vitro, spontaneously creating new potential substrates for the melanogenic factor in question, and b) recognized as substrates by more than one melanogenic protein in vitro.
Using protein kinase inhibitors, evidence was obtained that PKC activity is not associated with stimulation of tyrosinase, rather it seemed to be a negative regulator of the melanogenesis pathway.
ifpcs.med.umn.edu /16ipcc.html   (8168 words)

 Inhibition of the Mitogen-activated Protein Kinase Pathway Triggers B16 Melanoma Cell Differentiation -- Englaro et al. ...
Melanin biosynthesis or melanogenesis consists in a cascade of enzymatic and spontaneous reactions that converts tyrosine
In a previous report, we have shown the activation of ERK1 during cAMP-induced melanogenesis in B16 melanoma cells (10).
Inhibition of MAP Kinases by PD98059 Induces Melanogenesis-- Induction of melanogenesis in B16 melanoma cells is characterized by the stimulation of tyrosinase activity resulting from
www.jbc.org /cgi/content/full/273/16/9966   (4245 words)

 Why Tanning Pills Don't Work - Sunless.com
Examining diseases and disorders that prevent melanogenesis from taking place is instructive in understanding the limitations of nutritional supplements.
Since the object of this study is to find out if a blend of antioxidents increases melanogenesis, and the only cause of melanogenesis is UV exposure, leaving it out is incomprehensible.
Melanogenesis in cultured melanocytes can be substantially influenced by l-tyrosine and l-cysteine.
www.sunless.com /safe/tanningpillsdontwork.php   (4702 words)

 [No title]   (Site not responding. Last check: 2007-10-26)
By increasing natural melanogenesis, skin can be at least partially shielded from ultraviolet radiation, and tanning of the skin can be achieved without exposure of the skin to potentially damaging ultraviolet radiation.
More particularly, the present invention contemplates a composition, and method of using such, which is effective in stimulating melanogenesis in human skin, the composition comprising an effective amount of a prostaglandin effective in increasing levels of melanin in melanocytes in human skin.
An"effective amount"of the melanin-increasing agent is an amount which increases melanogenesis in the treated area of the subject.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=98/00100.980806&ELEMENT_SET=DECL   (7041 words)

 Amazon.ca: Books: Melanogenesis and Malignant Melanoma: Biochemistry, Cell Biology, Molecular Biology, Pathophysiology, ...   (Site not responding. Last check: 2007-10-26)
The purpose of this symposium was to promote communication and to increase the level of exchange of information on melanogenesis, pigmentary disorders and malignant melanoma.
The rapid progress in both the basic science and clinical medicine has necessitated a better understanding of the biological significance of melanin and malignant melanoma in order to be able to cure malignant melanoma.
This book will be of help to the readers by stimulating both further study and the promotion of more extensive understanding of melanogenesis, pigmentary disorders and treatment of malignant melanoma.
www.amazon.ca /exec/obidos/ASIN/0444822097   (359 words)

 Follicle.com - Patent: Use of emu oil for stimulating skin and hair growth
Thus, emu oil is useful to treat pigmentation disorders such as hypopigmentation, stimulating melanogenesis to enhance skin tanning, and treating disorders relating to disturbances in hair cycling such as alopecia, male pattern baldness, female baldness, and chemotherapy-induced alopecia.
A second aspect of the present invention generally involves enhancing melanogenesis in mammalian skin tissue by contacting the skin tissue with emu oil or a biologically active fraction thereof.
It can be concluded from these studies that the topical application of emu oil increased the synthesis of DNA in the epidermis which is a measure of increase in the proliferative activity of the epidermis.
www.follicle.com /section3/3_7_1.html   (5170 words)

 Nitric Oxide Produced by Ultraviolet-irradiated Keratinocytes Stimulates Melanogenesis -- Roméro-Graillet et al. ...
Melanogenesis was estimated by measuring the activity of
The activation of melanogenesis, the induction of tyrosinase and
Ballotti(1995)Mitogen-activated protein kinase pathway and AP-1 are activated during cAMP-induced melanogenesis in B-16 melanoma cells.
www.jci.org /cgi/content/full/99/4/635   (4988 words)

The major melanogenic chemical stimuli for mammalian melanocytes are the melanocortins, a family of peptide hormones derived from proopiomelanocortin.
On the other hand, we have identified two potent inhibitors of melanogenesis, TGFb and TNFa, whose mechanisms of action and possible crosstalk with the cAMP pathway are currently being analysed.
Transforming growth factor beta inhibits basal melanogenesis in B16/F10 mouse melanoma cells by increasing the rate of degradation of tyrosinase and its related proteins.
www.um.es /bbmbi/GruposInvest/Melano/Schemes.htm   (1288 words)

 European Hair Research Society - Abstract
In addition to important roles in social/sexual communication, one potential benefit of pigmented scalp hair in humans may be the rapid excretion of heavy metals, chemicals, and toxins from the body by their selective binding to melanin.
The primary distinguishing feature of follicular melanogenesis, compared to the continuous melanogenesis in the epidermis, is the tight coupling of hair follicle melanogenesis to the hair growth cycle.
Each hair cycle is associated with the re-construction of an intact hair follicle pigmentary unit at least for the first 10 cycles or so.
www.ehrs.org /conferenceabstracts/2002brussels/guestlectures/O-10-tobin.htm   (382 words)

 Faculty: Ashok Chakraborty - Dermatology
Biology of melanoma and melanogenesis.- Looking for glycosylation as an event of macrophage induced processes for melanocyte biology including melanoma metastasis, DNA analyses of primary and metastatic melanoma cells.
Identification of novel regulatory factors in the melanogenesis pathways, understanding of mechanisms involved in UVB mediated POMC expression in epidermal cells.
Chakraborty AK and Pawelek J. The enzymology of mammalian melanogenesis.
info.med.yale.edu /dermatology/dept/chakraborty.html   (736 words)

 eMedicine - Skin Lightening/Depigmenting Agents : Article by Michael P Tabibian, MD   (Site not responding. Last check: 2007-10-26)
It is considered one of the most effective inhibitors of melanogenesis in vitro and in vivo.
Because arbutin does not hydrolyze to liberate HQ, the latter agent is not responsible for the inhibitory effect of arbutin on melanogenesis.
However, tyrosinase activity was not affected, suggesting that the inhibition of melanogenesis occurs at the posttyrosinase step in the melanin biosynthetic pathway.
www.emedicine.com /derm/topic528.htm   (2407 words)

 Pigmentation enhancer and method - Patent 5589161
By increasing melanogenesis, skin can be at least partially shielded from ultraviolet radiation, and tanning of the skin can be achieved without exposure of the skin to potentially damaging ultraviolet radiation.
The present invention is directed to compositions and methods which increase melanogenesis in subjects.
An "effective amount" of the melanin-increasing agent is an amount which increases melanogenesis in the treated area of the subject.
www.freepatentsonline.com /5589161.html   (4510 words)

 Melano   (Site not responding. Last check: 2007-10-26)
dopa oxidase activity of tyrosinase is necessary for the formation of dopaquinone which is one of the key compounds in melanogenesis (66).
for melanogenesis specific melanogens on the one hand and for melanogenesis non- or less specific melanogens on the other, is also in agreement with clinical observations (39, 42).
Duchon, J.: Urinary melanogens as a mirror of melanogenesis in vivo.
www.ulb.ac.be /medecine/loce/espcr/journals/sbornik/melano.htm   (3981 words)

 Possible involvement of proteolytic degradation of tyrosinase in the regulatory effect of fatty acids on melanogenesis ...
Possible involvement of proteolytic degradation of tyrosinase in the regulatory effect of fatty acids on melanogenesis -- Ando et al.
Possible involvement of proteolytic degradation of tyrosinase in the regulatory effect of fatty acids on melanogenesis
The purpose of this study was to investigate the mechanism of
www.jlr.org /cgi/content/full/40/7/1312   (3071 words)

 The Science Advisory Board   (Site not responding. Last check: 2007-10-26)
The enzyme tyrosinase, commonly considered as the sole enzyme involved in melanogenesis, has long served as a target for the development of melanocytotoxic and depigmenting agents.
Since tyrosinase initiates melanogenesis, skin depigmentation would occur if melanogenesis is inhibited.
In the near future, I am planning on moving to Geneva to continue my research on new types of depigmenting and melanocytotoxic agents and to be trained as a dermatologist.
www.scienceboard.net /community/memberSpotlight.asp?spotid=15   (1157 words)

 [No title]
The most important concept is that the difference in pigmentation between light and dark skinned people is not the number of melanocytes but the mechanism of transfer of melanosomes -which are matured to melanin grains- to the keratinocytes.
Melanin synthesis is a complex process controlled partly by an enzyme called tyrosinase and it is only a part of the melanogenesis process.
Melanogenesis also involves the development of the melanosomes, the organelle of the melanocyte in which melanin is synthesized and the subsequent transfer of the melanosomes to keratinocytes.
www.farmeco.com /pages/news1.doc   (1073 words)

 Sphingosine-1-phosphate decreases melanin synthesis via sustained ERK activation and subsequent MITF degradation -- Kim ...
Melanogenesis is regulated by at least three melanocyte-specific
is involved in the regulation of melanogenesis in melanocytes.
Tsukamoto, K., Ueda, M. and Hearing, V. Melanogenesis in murine melanocytes is suppressed by infection with the v-rasHa oncogene.
jcs.biologists.org /cgi/content/full/116/9/1699   (4709 words)

 Untitled Document
The melanocyte cells transform the peptide tyrosinase into two different forms of melanin, which then is spread throughout the dermal cells and the keratinocytes via melanosomes to darken tissue.
Eumelanin is metabollized from DHICA and produces a brown color in hair in its intact form; pheomelanin is metabolized from 5,6-indolequione, which produces a red color in hair in its intact form.
Proving this theory, there is histological evidence in vitiligo patients that apoptosis is occurring in the unpigmented skin lesions: there is damage to the melanocytes and keratinocytes in these areas, and the melanocytes exhibit nuclear shrinking, vacuolization, loss of dendrites, and detachment.
www.bio.davidson.edu /Courses/Immunology/Students/Spring2003/Leese/Vitiligo.htm   (2237 words)

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