Melanosomes: Melanin-containing organelles found in melanocytes and melanophores.Melanins: Insoluble polymers of TYROSINE derivatives found in and causing darkness in skin (SKIN PIGMENTATION), hair, and feathers providing protection against SUNBURN induced by SUNLIGHT. CAROTENES contribute yellow and red coloration.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Melanocytes: Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Monophenol Monooxygenase: An enzyme of the oxidoreductase class that catalyzes the reaction between L-tyrosine, L-dopa, and oxygen to yield L-dopa, dopaquinone, and water. It is a copper protein that acts also on catechols, catalyzing some of the same reactions as CATECHOL OXIDASE. EC 1.14.18.1.Skin Pigmentation: Coloration of the skin.Hermanski-Pudlak Syndrome: Syndrome characterized by the triad of oculocutaneous albinism (ALBINISM, OCULOCUTANEOUS); PLATELET STORAGE POOL DEFICIENCY; and lysosomal accumulation of ceroid lipofuscin.Pigmentation: Coloration or discoloration of a part by a pigment.Hypopigmentation: A condition caused by a deficiency or a loss of melanin pigmentation in the epidermis, also known as hypomelanosis. Hypopigmentation can be localized or generalized, and may result from genetic defects, trauma, inflammation, or infections.Melanophores: Chromatophores (large pigment cells of fish, amphibia, reptiles and many invertebrates) which contain melanin. Short term color changes are brought about by an active redistribution of the melanophores pigment containing organelles (MELANOSOMES). Mammals do not have melanophores; however they have retained smaller pigment cells known as MELANOCYTES.gp100 Melanoma Antigen: A melanosome-associated protein that plays a role in the maturation of the MELANOSOME.Myosin Type V: A subclass of myosin involved in organelle transport and membrane targeting. It is abundantly found in nervous tissue and neurosecretory cells. The heavy chains of myosin V contain unusually long neck domains that are believed to aid in translocating molecules over large distances.rab GTP-Binding Proteins: A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.Albinism, Oculocutaneous: Heterogeneous group of autosomal recessive disorders comprising at least four recognized types, all having in common varying degrees of hypopigmentation of the skin, hair, and eyes. The two most common are the tyrosinase-positive and tyrosinase-negative types.Albinism, Ocular: Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.Feathers: Flat keratinous structures found on the skin surface of birds. Feathers are made partly of a hollow shaft fringed with barbs. They constitute the plumage.Pigment Epithelium of Eye: The layer of pigment-containing epithelial cells in the RETINA; the CILIARY BODY; and the IRIS in the eye.Hair Color: Color of hair or fur.Lipofuscin: A naturally occurring lipid pigment with histochemical characteristics similar to ceroid. It accumulates in various normal tissues and apparently increases in quantity with age.Catechol Oxidase: An enzyme of the oxidoreductase class that catalyzes the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. EC 1.10.3.1.Melanosis: Disorders of increased melanin pigmentation that develop without preceding inflammatory disease.Albinism: General term for a number of inherited defects of amino acid metabolism in which there is a deficiency or absence of pigment in the eyes, skin, or hair.Pigments, Biological: Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms.Adaptor Protein Complex 3: An adaptor protein complex found primarily on perinuclear compartments.Melanocyte-Stimulating Hormones: Peptides with the ability to stimulate pigmented cells MELANOCYTES in mammals and MELANOPHORES in lower vertebrates. By stimulating the synthesis and distribution of MELANIN in these pigmented cells, they increase coloration of skin and other tissue. MSHs, derived from pro-opiomelanocortin (POMC), are produced by MELANOTROPHS in the INTERMEDIATE LOBE OF PITUITARY; CORTICOTROPHS in the ANTERIOR LOBE OF PITUITARY, and the hypothalamic neurons in the ARCUATE NUCLEUS OF HYPOTHALAMUS.Pigmentation DisordersMelanoma, Amelanotic: An unpigmented malignant melanoma. It is an anaplastic melanoma consisting of cells derived from melanoblasts but not forming melanin. (Dorland, 27th ed; Stedman, 25th ed)Dihydroxyphenylalanine: A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific.Melanoma: A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)Skin Absorption: Uptake of substances through the SKIN.Hair: A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.Melanoma, Experimental: Experimentally induced tumor that produces MELANIN in animals to provide a model for studying human MELANOMA.Microphthalmia-Associated Transcription Factor: A basic helix-loop-helix leucine zipper transcription factor that regulates the CELL DIFFERENTIATION and development of a variety of cell types including MELANOCYTES; OSTEOCLASTS; and RETINAL PIGMENT EPITHELIUM. Mutations in MITF protein have been associated with OSTEOPETROSIS and WAARDENBURG SYNDROME.Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.Retinal Pigment Epithelium: The single layer of pigment-containing epithelial cells in the RETINA, situated closely to the tips (outer segments) of the RETINAL PHOTORECEPTOR CELLS. These epithelial cells are macroglia that perform essential functions for the photoreceptor cells, such as in nutrient transport, phagocytosis of the shed photoreceptor membranes, and ensuring retinal attachment.Naphthols: Naphthalene derivatives carrying one or more hydroxyl (-OH) groups at any ring position. They are often used in dyes and pigments, as antioxidants for rubber, fats, and oils, as insecticides, in pharmaceuticals, and in numerous other applications.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Adaptor Protein Complex beta Subunits: A family of large adaptin protein complex subunits of approximately 90-130 kDa in size.Lysosomes: A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Intramolecular Oxidoreductases: Enzymes of the isomerase class that catalyze the oxidation of one part of a molecule with a corresponding reduction of another part of the same molecule. They include enzymes converting aldoses to ketoses (ALDOSE-KETOSE ISOMERASES), enzymes shifting a carbon-carbon double bond (CARBON-CARBON DOUBLE BOND ISOMERASES), and enzymes transposing S-S bonds (SULFUR-SULFUR BOND ISOMERASES). (From Enzyme Nomenclature, 1992) EC 5.3.alpha-MSH: A 13-amino acid peptide derived from proteolytic cleavage of ADRENOCORTICOTROPIC HORMONE, the N-terminal segment of ACTH. ACTH (1-13) is amidated at the C-terminal to form ACTH (1-13)NH2 which in turn is acetylated to form alpha-MSH in the secretory granules. Alpha-MSH stimulates the synthesis and distribution of MELANIN in MELANOCYTES in mammals and MELANOPHORES in lower vertebrates.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Spectrophotometry, Atomic: Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.X-Ray Absorption Spectroscopy: Analysis of the energy absorbed across a spectrum of x-ray energies/wavelengths to determine the chemical structure and electronic states of the absorbing medium.Jejunum: The middle portion of the SMALL INTESTINE, between DUODENUM and ILEUM. It represents about 2/5 of the remaining portion of the small intestine below duodenum.Adaptor Protein Complex 1: A clathrin adaptor protein complex primarily involved in clathrin-related transport at the TRANS-GOLGI NETWORK.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Optical Phenomena: LIGHT, it's processes and properties, and the characteristics of materials interacting with it.Exophiala: A normally saprophytic mitosporic Chaetothyriales fungal genus. Infections in humans include PHAEOHYPHOMYCOSIS; and PERITONITIS.. Exophiala jeanselmei (previously Phialophora jeanselmei) is an etiological agent of MYCETOMA.Organelle Size: The quantity of volume or surface area of ORGANELLES.Laccase: A copper-containing oxidoreductase enzyme that catalyzes the oxidation of 4-benzenediol to 4-benzosemiquinone. It also has activity towards a variety of O-quinols and P-quinols. It primarily found in FUNGI and is involved in LIGNIN degradation, pigment biosynthesis and detoxification of lignin-derived products.Hyperpigmentation: Excessive pigmentation of the skin, usually as a result of increased epidermal or dermal melanin pigmentation, hypermelanosis. Hyperpigmentation can be localized or generalized. The condition may arise from exposure to light, chemicals or other substances, or from a primary metabolic imbalance.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Dequalinium: A topical bacteriostat that is available as various salts. It is used in wound dressings and mouth infections and may also have antifungal action, but may cause skin ulceration.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Cysteinyldopa: Found in large amounts in the plasma and urine of patients with malignant melanoma. It is therefore used in the diagnosis of melanoma and for the detection of postoperative metastases. Cysteinyldopa is believed to be formed by the rapid enzymatic hydrolysis of 5-S-glutathionedopa found in melanin-producing cells.Agaricales: An extensive order of basidiomycetous fungi whose fruiting bodies are commonly called mushrooms.Mice, Mutant Strains: Mice bearing mutant genes which are phenotypically expressed in the animals.Mice, Inbred C57BLCryptococcus neoformans: A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Epidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.Spectrophotometry, Infrared: Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Dyneins: A family of multisubunit cytoskeletal motor proteins that use the energy of ATP hydrolysis to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.
Melanin is produced inside small membrane-bound packages called melanosomes. People with naturally occurring dark skin have ... it can absorb more energy from UVR and thus offers better protection against sunburns and by absorption and dispersion UV rays ... Humans with dark skin are naturally blessed with melanin (especially eumelanin), and have more melanosomes which provide a ... Melanin is derivative of the amino acid tyrosine. Eumelanin is the dominant form of melanin found in human skin. Eumelanin ...
Kono, R. and McGinness, J.E.: Anomalous Absorption and Sound in DBA Melanins. J. Applied Physics, 50(3): 1236-1244, 1979. ... Anomalous low temperature specific heat results in melanins and intact melanosomes. Nature 259:505, 1976. Filatovs, J., ... Kirkpatrick, D.S., McGinness, J.E., Moorhead, W.D., Corry, P.M., and Proctor, P.H.: Melanin-Water-Ion Dielectric Interaction. ... The department had an interest in the physical properties of melanin as a possible hook to treating melanoma. While of enormous ...
The degree of dispersion of the melanin, which is in subcellular bundles called melanosomes, has some influence on the observed ... and their eyes appear blue due to scattering and selective absorption from the posterior epithelium. If melanin is deposited ... Iris color is due to variable amounts of eumelanin (brown/black melanins) and pheomelanin (red/yellow melanins) produced by ... the only pigment that contributes substantially to normal human iris color is the dark pigment melanin. The quantity of melanin ...
Absorption spectrum of melanin Tyrosine metabolism in KEGG Melanogenesis in KEGG. ... Melanocytes insert granules of melanin into specialized cellular vesicles called melanosomes. These are then transferred into ... Melanins have very diverse roles and functions in various organisms. A form of melanin makes up the ink used by many ... Melanin produced by plants are sometimes referred to as 'catechol melanins' as they can yield catechol on alkali fusion. It is ...
This was contradicted in 2014 by the discovery of melanosomes, black melanin-bearing structures, in the skin of ichthyosaur ... This would have been an adaptation for an improved oxygen absorption, also in view of the low oxygen levels during the Toarcian ... This study noted that a basal layer of melanosomes in the skin is ubiquitous in reptile coloration, but does not necessarily ...
Once synthesised, melanin is contained in a special organelle called a melanosome and moved along arm-like structures called ... The agreement of the action spectrum with the absorption spectrum of DNA points towards the formation of cyclobutane pyrimidine ... Melanosomes are vesicles that package the chemical inside a plasma membrane. The melanosomes are organized as a cap protecting ... Tyrosinase is required for melanocytes to produce melanin from the amino acid tyrosine. Albinism may be caused by a number of ...
Melanin is produced inside small membrane-bound packages called melanosomes. Humans with naturally occurring light skin have ... Light skin provides better absorption qualities of ultraviolet radiation. This helps the body to synthesize higher amounts of ... Melanin is a derivative of the amino acid tyrosine. Eumelanin is the dominant form of melanin found in human skin. Eumelanin ... Melanin is produced in specialized cells called melanocytes, which are found in the lowest level of the epidermis. ...
Stray-light absorption by melanin granules of pecten oculi is also considered to give rise to small increments in temperature ... possible involvement of melanosomes in protecting the pecten against damage by ultraviolet light", Journal of Anatomy, 185 (Pt ...
Melanin protects the skin from ultra-violet radiation in sunlight. Melanosomes block harmful electromagnetic radiation from the ... The costs of albinism for marine mammals may include reduced heat absorption in colder waters, poor camouflage from predators, ... Melanin is an organic pigment that produces most of the colour seen in mammals. Depending on how it is created, melanin comes ... Melanin has several functions in most mammals and other animals; these are disrupted by albinism. Melanin functions in the ...
Melanin is often involved in the absorption of light; in combination with a yellow pigment, it produces a dull olive-green. In ... By comparing the shape of the fossil melanosomes to melanosomes from extant birds, the color and pattern of the feathers on ... The presence of melanin in feathers increases their resistance to abrasion. One study notes that melanin based feathers were ... In one fossil specimen of the Parave Anchiornis huxleyi, the features are so well preserved that the melanosome (pigment cells ...
Melanosome transfer: Melanosomes along with the melanin they contain is transferred from melanocytes to keratinocytes when ... Glutathione can be combined with many other agents like vitamin C to increase its absorption, N-acetyl cysteine to boost its ... Melanin in synthesized in melanosomes which are organelles produced in melanocytes. Melanocytes are cells dedicated to this ... See § Preventing the transfer of melanosomes to keratinocytes. Skin whitening agents work by reducing the presence of melanin ...
Pecten cells are packed with dark melanin granules, which have been theorized to keep this organ warm with the absorption of ... RPE melanosome zone Hypo-reflective RPE mitochondria zone + Junction between the RPE & Bruch's membrane Very Hyper-reflective ... The black pigment melanin in the pigment layer prevents light reflection throughout the globe of the eyeball; this is extremely ...
Loss of melanin/. amelanism. Albinism. *Oculocutaneous albinism. *Ocular albinism. Melanosome. transfer. *Hermansky-Pudlak ... Processing and homogenizing causes carotene to become more available for absorption. A small 2.5 ounce jar of baby food sweet ...
Melanosomes are vesicles or packages of the chemical inside a plasma membrane. The melanin is in organelles called "melanosomes ... The agreement of the action spectrum with the absorption spectrum of DNA points towards the formation of cyclobutane pyrimidine ... Once made, melanin is moved along arm-like structures called dendrites in a special container called a melanosome which is ... Barden H and Levine S (1983). "Histochemical observations on rodent brain melanin". Brain Res. Bull. 10 (6): 847-851. doi: ...
This was contradicted in 2014 by the discovery of melanosomes, black melanin-bearing structures, in the skin of ichthyosaur ... This would have been an adaptation for an improved oxygen absorption, also in view of the low oxygen levels during the Toarcian ... This study noted that a basal layer of melanosomes in the skin is ubiquitous in reptile coloration, but does not necessarily ...
Jacques SL (1998) Melanosome absorption coefficient. http://omlc.ogi.edu/spectra/melanin/mua.html ... and continues to pass through layers of the exo-endocuticle until it is absorbed by the pigment melanin in the brown-colored ...
... decreasing light absorption (3). Melanocytes produce melanin within melanosomes, specialized membrane-bound organelles (MBOs). ... Stage 3 melanosomes have deposits of dense melanin on the filaments. Stage 4 melanosomes are the mature melanosome and are ... 3D, arrowheads). The ring-like appearance is enhanced by the presence of melanin in the more mature melanosomes. Ring-like ... The regions between the accumulated melanosomes in the dv/dv cells (B) contain cytoplasm lacking melanosomes. (Bar = 50 μm.) ...
Pigment granules, in particular the melanin granules or melanosomes, contained within melanophores, absorb light. Thus by ... a difference in light absorption and therefore pigmentation level may be detected between test and control fish. A suitable ... the hypothalamus then inducing pituitary secretion of either a hormone causing melanin aggregation or one causing melanin ... the hypothalamus then inducing pituitary secretion of either a hormone causing melanin aggregation or one causing melanin ...
2014). Extant melanosomes are known to exist in both spherical and elongate forms depending on the type of melanin they contain ... 4d) show a similar absorption pattern to the tadpole (Fig. 4a, b), and some show a different one (Fig. 4d). In all cases, the ... Enspel Bacterial autolithification Amphibian Melanin Melanosomes Geochemistry This article is a contribution to the special ... 2004). Melanin can act like a metal ion sink during diagenesis, leading to the build-up of these metals where melanin was ...
Melanin, an endogenous cutaneous pigment which is most concentrated in the basal layer of the epidermis, has an absorption ... Melanosomes, which are melanocyte-specific organelles, densely packed with melanin, are predominantly found within melanocytes ... and it is expected that shorter wavelengths within the melanin absorption spectrum will provide desirable results. Due to ... At 504 nm, some effect on melanin is noted at 2 J/cm2, and damage is seen above 4 J/cm2 . The depth of penetration in caucasian ...
Apparent concentrations of melanin, oxy-, and deoxy-hemoglobin were calculated from the absorption spectra. In the second ... Most of scattering is attributed to collagen fibers and in pigmented skin to melanosomes. Traditionally skin redness is ... Melanin showed a significant increase on day 7 and remained relatively constant for the next 3 weeks, correlating well with the ... Application of pressure or H2O2 did not significantly alter the levels of oxy-hemoglobin or melanin. In this report we present ...
Melanin is produced inside small membrane-bound packages called melanosomes. People with naturally occurring dark skin have ... it can absorb more energy from UVR and thus offers better protection against sunburns and by absorption and dispersion UV rays ... Humans with dark skin are naturally blessed with melanin (especially eumelanin), and have more melanosomes which provide a ... Melanin is derivative of the amino acid tyrosine. Eumelanin is the dominant form of melanin found in human skin. Eumelanin ...
What blew my mind was that melanosomes (melanin-harboring organelles) are physically attached to mitochondria - all supported ... Theres a good book called "Melanin: energy from light and the souls ascent" It talks about the scientific basis for melanin- ... Theres a good book called "Melanin: energy from light and the souls ascent" It talks about the scientific basis for melanin- ... Like passive solar energy absorption, active cloud plasma absorption, stuff like that. 557x ...
Without the broadband absorption provided by melanin, this white colour illumination would swamp out the blue, leading to a ... Production of non-iridescent blue colour by birds also involves co-localized melanosomes (figure 2III). These melanin-filled ... g) Leucistic (i.e. lacking melanin) Stellers jay (Cyanocitta sterlleri) illustrating the effects of loss of melanin on blue ... through broadband light absorption across the visible spectrum [10]. There are two chemical variants of melanin, black ...
Kono, R. and McGinness, J.E.: Anomalous Absorption and Sound in DBA Melanins. J. Applied Physics, 50(3): 1236-1244, 1979. ... Anomalous low temperature specific heat results in melanins and intact melanosomes. Nature 259:505, 1976. Filatovs, J., ... Kirkpatrick, D.S., McGinness, J.E., Moorhead, W.D., Corry, P.M., and Proctor, P.H.: Melanin-Water-Ion Dielectric Interaction. ... The department had an interest in the physical properties of melanin as a possible hook to treating melanoma. While of enormous ...
RELATED CHANGES IN THE FLUORESCENCE OF MELANIN and LIPOFUSCIN GRANULES OF THE RETINAL PIGMENT EPITHELIUM: A TIME‐RESOLVED ... Age‐related changes in the morphology, absorption and fluorescence of mel‐anosomes and lipofuscin granules of the retinal ... Young melanin showed spectral patterns similar to those of bovine melanin, while a yellow‐orange fluorescence band appeared in ... Young melanin showed spectral patterns similar to those of bovine melanin, while a yellow‐orange fluorescence band appeared in ...
Figure 18. Absorption Spectra of Melanins, adapted from Wolfram et al. [4], with permission from Society of Cosmetic Chemists, ... In the reference to the importance of the scattering/absorption phenomenon, Figure 10 reflects the modulation of melanosomes in ... Figure 18. Absorption Spectra of Melanins, adapted from Wolfram et al. [4], with permission from Society of Cosmetic Chemists, ... It involves, through light absorption an excitation of the melanin moiety to a state in which it reacts with oxygen of the air ...
This latter activity requires functional melanosomes, which contain enzymes that catalyze the production of melanin (e.g. ... An important and evolutionarily conserved role of the RPE is the absorption of stray light to increase visual acuity and reduce ... or melanosome transport (RAB27a) and factors implicated in melanosome biogenesis (Gpnmb, Slc45a2, Slc24a5 and Slc3a2). ... link between melanin synthesis and melanosome biogenesis. Mol Cell Biol 24: 6550-6559. ...
... indicating that melanin is a better absorber of visible light than black polystyrene. The NIR melanosome absorption ... Melanosomes were irradiated using a 1064-nm Q-switched Nd:YAG (doubled for 532-nm irradiation). For comparison to melanosome ... Threshold data and extrapolated nucleation temperatures were used to estimate melanosome absorption coefficients in the visible ... The terahertz (THz) absorption and index of refraction of brain tissues from a mouse model of Alzheimers disease (AD) and a ...
... in which melanosomes and pigmented cells are preferentially altered. Due to the broad absorption spectrum of melanin, this ...
... absorption and fluorescence), 37 melanin content, 11 and light-induced chemical reactivity. 10 An age-related increase in the ... Moreover, bovine melanosomes exert protection similar to that of synthetic melanin, suggesting that melanin is the main factor ... In our previous studies, the photodegradation of synthetic melanin, porcine melanosomes, and bovine melanosomes was induced by ... In comparison with bovine melanosomes, human melanosomes proved significantly less effective than bovine melanosomes at ...
as well as melanin, the primary absorber in melanotic melanoma cells, have strong optical absorption but negligible ... Images of a cluster of melanosomes-small organelles containing melanin-were acquired using conventional PAM, second-order (. c ... The energy deposition due to single photon absorption is A. e. (. r. →. −. r. →. 0. ,. z. −. z. 0. ). =. ∫. −. ∞. ∞. μ. a. (. r ... is the optical absorption coefficient (. m. −. 1. ) at time t. , and I. (. r. →. −. r. →. 0. ,. z. −. z. 0. ,. t. ). is the ...
The skin melanins are synthetized and deposited within melanocyte-specialized cellular organelles called melanosomes that are ... Purified DCT contains two Zn atoms per protein molecule as measured by atomic absorption spectroscopy and Zn2+ chelation ... the melanosomes, the site of melanin synthesis and storage. In parallel with our early research on TRP1 intracellular ... L-Dopachrome is the second branch point which under the unique L-DCT action is transformed into DHICA (Figure 7). Melanin ...
These hues (figure S2, electronic supplementary material) may reflect absorption of metal ions into the melanosomes during ... Melanins are synthesized in a special class of pigment cells (melanocytes) and are packaged within organelles (melanosomes) ... e) Cross-section of barbule showing thin outer layer and aligned melanosomes within. R, ramus with loose aligned melanosomes; ... 2006). The melanosomes may be rod shaped as in some passerines (e.g. Quiscalus: figure 2a,b,e), galliform birds (e.g. Tetrao) ...
Light absorption by melanosomes. If one is in interested in the effects caused by irradiating melanosomes in vivo, then one ... Discussion of the melanin absorption coefficient. Light absorption by the epidermis. If one is interested in the amount of ... Cutaneous melanosomes are variable and may have 1/4th to 1/10th the melanin concentration of the RPE melanosomes. And there are ... Melanosomes may contain a variable amount of melanin. The melanosomes of the retinal pigmented epithelium (RPE) have a very ...
Melanin is produced in melanosomes from tyrosine, and it is the substance responsible for the particular coloration of the skin ... it tends to decrease appetite and minimize absorption and storage of some fats, beneficial in cases of cholesterol or ... Also it has effect on the mucosa of the skin and hair, for their stimulatory effect of melanin. ...
... study combines geochemical analyses with morphological observations to investigate the preservation of melanosomes and melanin ... When mapped, the carboxylic acid group absorption faithfully replicates the visually dark areas of the feathers. Electron ... spectroscopy of one specimen demonstrates the presence of organic signals but proved too insensitive to resolve melanin. ... Recent studies have shown evidence for the preservation of colour in fossilized soft tissues by imaging melanosomes, melanin ...
... as it interrupts the UV-triggered chemical signals that turn on melanin production and inhibits the transfer of melanosomes to ... This will offer maximum absorption and effectiveness.. How Can I Achieve The Best Possible Results? ... Other research indicates that we can also control melanin formation by affecting the signaling process involved in melanin ... concentration of Lactic Acid will slow melanin synthesis. This approach to affect melanin synthesis is unique to Lactic Acid ...
... of their absorption properties and an understanding of how the absorption varies with the molecular composition of melanin. ... Ultraviolet Absorption Coefficients of Melanosomes Containing Eumelanin As Related to the Relative Content of DHI and DHICA  ... Central to understanding the photochemical function(s) of melanosomes is the determination ...
Although the cause is not completely understood, it is known that the over-production of melanin creates its characteristic ... Melanocytes are cells that live in our dermis and produce melanin. Melanin is bundled up in melanosomes, which move up to the ... Melanin has many positive functions, including the absorption of UV light, which diminishes the risk of skin cancer and ... While the over-production of melanin (as seen in melasma) does not pose a medical risk, its emotional damage can be high, ...
  • Barker, Pierrette Dayhaw 1991-08-01 00:00:00 The photophysical properties of purified populations of melanin and lipofuscin granules from human retinal pigment epithelium, and their changes with donor age, have been investigated using high‐sensitivity time‐resolved fluorescence spectroscopy techniques with picosecond gating capabilities. (deepdyve.com)
  • Adding bovine melanosomes or synthetic melanin to nonpigmented bovine RPE cells resulted in a concentration-dependent decrease in the rate of oxidation to levels similar to those of pigmented bovine retinal pigment epithelium. (arvojournals.org)
  • Differences in the location and density of melanosomes in the retinal pigment epithelium may have an impact on the effect of laser energy delivered to those tissues. (spie.org)
  • The goal of our study is to identify the three-dimensional distribution of melanosomes within the retinal pigment epithelium (RPE) for the use of those modeling laser tissue effects. (spie.org)
  • Age-dependent photoionization thresholds of melanosomes and lipofuscin isolated from human retinal pigment epithelium cells. (duke.edu)
  • Because melanin is an aggregate of smaller component molecules, there are a number of different types of melanin with differing proportions and bonding patterns of these component molecules. (wikidoc.org)
  • The dilute coat color phenotype is caused by irregular clumping of pigment in the hair, but amounts of melanin are unchanged from wild-type controls. (pnas.org)
  • The presence of melanin in the archaea and bacteria kingdoms is an issue of ongoing debate amongst researchers in the field. (wikidoc.org)
  • Because the arms of the melanophores extend between and over the other types of chromatophore (generating yellows, reds, blues, etc.), varying the degree of dispersion of the melanin can conceal or reveal those chromatophores, thereby varying the animal's colour. (theconversation.com)
  • The degree of dispersion of the melanin, which is in subcellular bundles called melanosomes, has some influence on the observed color, but melanosomes in the iris of man and other vertebrates are not mobile, and the degree of pigment dispersion cannot be reversed. (medizines.net)
  • The physiologically significant dose-related melanin dispersion effects of berberine per se were found to be completely abolished by propranolol, which is a specific beta-2 adrenergic receptor blocker. (worldwidescience.org)
  • Many botanical extracts also inhibit melanin production, including Kiwi Fruit, Mulberry, Licorice and Giant Fennel. (dermalinstitute.com)
  • We demonstrate that the partial depletion of Tyr in the mouse was not sufficient to induce significant decreases in melanin accumulation in the mouse hair follicle, suggesting that TYR may not be an ideal target for the treatment of hyperpigmentary disorders. (escholarship.org)
  • This approach was demonstrated by using nonlinear PA flow cytometry platform for label-free detection of circulating melanoma cells in blood background in vitro and in vivo.Nonlinearly amplified PA signals from overheated melanin nanoclusters in melanoma cells became detectable above still linear blood background.Nonlinear nanobubble-based photoacoustics provide new opportunities to significantly (5-20-fold) increase PA contrast of single nanoparticles, cells, viruses and bacteria in complex biological environments. (nih.gov)
  • Nonlinearly amplified PA signals from overheated melanin nanoclusters in melanoma cells became detectable above still linear blood background. (nih.gov)
  • PT images and signals from single melanoma cells with low (d and f) and high (e and g) melanin content. (nih.gov)
  • The amount of melanin in melanoma cells widely varies (Fig. 2a-c) depending on several factors (cell line, growing methods, culturing time, etc. (nih.gov)
  • Melanin pigement-producing cells squeezed within the bottom strata of epithelium. (studystack.com)
  • Photoacoustic (PA) detection of single absorbing targets such as nanoparticles or cells can be limited by absorption background. (nih.gov)
  • a and b) Cells with various melanin content suspended in PBS. (nih.gov)
  • Specifically, the PT thermal lens signal amplitude and PT image structure in individual live cells were used as indicators of average melanin content (through average cell absorption) and melanin cellular spatial distribution, respectively. (nih.gov)
  • Melanin is yellowish-brown to dark brown in the stromal pigment cells, and black in the iris pigment epithelium, which lies in a thin but very opaque layer across the back of the iris. (medizines.net)
  • The scientists found slc24a5 to be highly expressed in the melanin-producing cells of both zebrafish and mammals. (beds.ac.uk)
  • This trend was found to be comparable to the decrease in retinal pigmented epithelial (RPE) layer absorption coefficients reported over the same wavelength region. (spie.org)
  • Here, we report label-free photoacoustic (PA) nanoscopy, which is exquisitely sensitive to optical absorption, with an 88 nm resolution. (cdc.gov)
  • Photoacoustic microscopy (PAM) is an effective in vivo functional and molecular imaging tool based on optical absorption contrast. (cdc.gov)
  • Young melanin showed spectral patterns similar to those of bovine melanin, while a yellow‐orange fluorescence band appeared in melanin samples from older age groups. (deepdyve.com)
  • Indeed, several studies have shown that porcine or bovine RPE melanosomes can offer substantial protection against photosensitized oxidation mediated by a cationic photosensitizer 4 and iron ion-mediated generation of hydroxyl radical or lipid peroxidation. (arvojournals.org)
  • Thresholds for microcavitation of isolated bovine and porcine melanosomes were determined using single nanosecond (ns) laser pulses in the NIR (1000 - 1319 nm) wavelength regime. (spie.org)
  • Investigation of feathers from the famous Middle Eocene Messel Oil Shale near Darmstadt, Germany shows that they are preserved as arrays of fossilized melanosomes, the surrounding beta-keratin having degraded. (royalsocietypublishing.org)
  • In a previous investigation on a fossil feather such structures were indeed thought to be bacteria covered with a glycocalyx ( Figure 1a , ), however in light of the recent studies on fossil feathers this assessment has been re-evaluated and the structures have since been identified as melanosomes surrounded by the remains of decaying β-keratin fibres . (plos.org)
  • It is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. (royalsocietypublishing.org)
  • Despite the great interspecific variation in the organization of such structures in bird plumage, melanin layers are usually considered too opaque, suggesting its main role is to delineate the outermost keratin layer and absorb incoherently scattered stray light. (royalsocietypublishing.org)
  • We combined spectrometry, electron microscopy and thin-film optical modelling to describe the UV-reflecting iridescent colour of feather barbules of male blue-black grassquits ( Volatinia jacarina ), characterized by a keratin layer overlying a single melanin layer. (royalsocietypublishing.org)
  • Application of pressure or H 2 O 2 did not significantly alter the levels of oxy-hemoglobin or melanin. (spiedigitallibrary.org)
  • 10 However, label-free nanoscopy of biological structures with chromophores having no or low fluorescence quantum yields-such as hemoglobin, cytochromes, melanin, DNA, and RNA-remains elusive. (cdc.gov)
  • 1 2 Melanin exhibits several potentially antioxidant properties, such as sequestration of redox-active metal ions, scavenging of free radicals, and thermal deactivation of electronically excited states of photosensitizers and oxygen. (arvojournals.org)
  • 4 5 6 However, some of these studies also showed that photobleaching of melanosomes results in a reduced capacity to bind metal ions or to offer protection against metal ion-dependent hydrogen peroxide decomposition and lipid peroxidation. (arvojournals.org)
  • These hues (figure S2, electronic supplementary material) may reflect absorption of metal ions into the melanosomes during diagenesis. (royalsocietypublishing.org)
  • 2 Although the exact mechanisms of action of PBM remain uncertain, robust evidence from absorption spectra indicates that a copper atom in Complex IV of the mitochondrial electron transport chain is the photoabsorber of PBM. (arvojournals.org)
  • In this report, we present data that argue strongly against hypotheses i and ii (process formation and melanosome maturation) listed above and establish that dilute function is necessary for localization of melanosomes within the cytoplasm, consistent with hypotheses iii and iv (transport or tethering) above. (pnas.org)