601
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Abstract
The constituents of the melanin complex from mycelial forms of Fonsecaea pedrosoi were partially characterized. The pigment was mainly accumulated on large alkali-extractable, electron-dense cytoplasmic bodies (melanosomes) and, apparently, on the outer layer of the cell wall as external deposits within verrucose outgrowths. Using electron microscopy and Thiéry's periodate/thiosemicarbazide/silver proteinate staining method, glycogen-like particles were also detected at the periphery of the cells. Melanin constituents comprised aromatic and aliphatic/glycosidic structures with a predominance of the latter. Infrared spectra showed the presence of hydroxyl, carbonyl and carboxyl groups. The aliphatic/glycosidic moiety consisted of fatty acids and polysaccharides with protein, in a ratio protein/polysaccharide 1:15. Rhamnose, mannose, galactose and glucose (in the ratio 1:2:4:3.5) were the constituents of the polysaccharide. Lipid components included even-numbered, saturated and unsaturated fatty acids (in the ratio 2:1) ranging from C16 to C18. Palmitic and oleic acids were the prominent fatty acids. Aspartic and glutamic acids, leucine, glycine and alanine were the major amino acids. Non-pigmented cells of F. pedrosoi were studied for comparison with the pigmented forms: they did not accumulate acid-insoluble precursors of melanin.
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Affiliation(s)
- C S Alviano
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Ilha, do Fundão, Brazil
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602
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Abstract
Oral mucosa from six sites in 95 autopsies was tested for melanin using the Masson-Fontana silver reduction method. Melanin was detected in 51.6% of labial, 46.3% of palatal, 45.3% of buccal, 28.4% of mandibular gingival, 25.3% of lingual and 21.1% of maxillary gingival samples. 93.7% of epidermal samples from the same population were positive. In 24.2% of the subjects there was no detectable melanin at any intraoral site and 4.2% showed activity in all six sites. The mean number of positive oral sites per individual was 2.2. There are thus regional differences in oral epithelial melanocyte activity, but no parallel with the known regional incidence of primary oral melanoma.
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Affiliation(s)
- A W Barrett
- Department of Oral Biology, Dental School, Newcastle upon Tyne, U.K
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603
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Affiliation(s)
- B I Baker
- School of Biological Sciences, University of Bath, Cleverton Down, England
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604
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Abstract
The scavenger activity against O2-. of some flavonoids and melanins (synthetic melanins and melanins isolated from animal tissues, vegetable seeds, and mushroom spores) has been studied by ESR spectrometry. All these substances, except flavon and flavanone, diminish the signal of O2-. generated in vitro by a system containing H2O2 and acetone in an alkaline medium. It is shown that the presence of hydroxyl groups in the B ring of flavonoids is essential for their scavenger activity. Moreover, the presence of a hydroxyl at C-3 enhances the scavenger ability of flavonoids. Generally, aglycons are more active than their glycosides. It seems plausible that the antioxidant property of these substances comes from their scavenger activity against O2-(.). It is also pointed out that the scavenger activity shown by melanins, is strictly correlated with their nature of stable free radical.
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Affiliation(s)
- G Sichel
- Istituto di Biologia Generale, Università di Catania, Italy
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605
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Baker BI, Kinsman RG, Moss CA, White PD, Paul PK, Brown DW, Campbell MM, Osguthorpe DJ. Structure-activity studies with fragments and analogous of salmonid melanin-concentrating hormone. Peptides 1990; 11:1103-8. [PMID: 2087435 DOI: 10.1016/0196-9781(90)90137-t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A number of cyclic and linear fragments and analogues of MCH were synthesized and their biological potencies tested using the isolated carp scale melanophore assay. In this system the cyclic portion MCH(5-14) exhibited only 0.1% bioactivity, which was markedly enhanced by the addition of the exocyclic sequences MCH(15-17) and MCH(1-4). The exocyclic sequence itself, MCH(1-4,15-17), had minimal activity, however. Substitution of Tyr11 with phenylalanine reduced the potency of the ring structure MCH(5-14) by about 4-fold. Substitution of Gly8 with D-alanine reduced the potency of MCH(5-14) 16-fold, while both substitutions together caused a still more marked reduction (200-fold) in bioactivity. Linearized fragments of MCH, extending from MCH(15-17) to [Cys(Acm)5,14]MCH(1-17), showed a progressive increase in potency. The linearized forms of MCH, MCH(5-17) and MCH(5-14), were approximately 100-fold or less potent than their cyclic forms. The significant increases in bioactivity produced by the addition of the C- and N-terminal exocyclic sequence even to these linearized forms further emphasizes the importance of these regions for interaction at the receptor site.
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Affiliation(s)
- B I Baker
- School of Biological Sciences, Bath University, U.K
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606
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Abstract
A series of experiments was performed on lyophylized melanosomes in order to analyze the melanin in the natural state as polymerized into these organelles and to verify in such biological amorphous material the possibility of obtaining intensity scattering curves from which Bragg distances can be calculated. The results confirm the feasibility of the method and show that melanins in melanosomes maintain many structural features of the purified form and that the biochemical composition of the organelles can be responsible for the observed differences in the diffractograms. The presence in melanosomes of supramolecular paracrystalline aggregates was also clearly demonstrated.
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Affiliation(s)
- M G Bridelli
- Department of Physics, University of Parma, Italy
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607
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Abstract
A seventeen-month-old female had a pigmented nodule on her left lower leg. The excised lesion was histologically diagnosed as a Spitz nevus, composed mainly of spindle-shaped melanocytes containing large amounts of melanin pigment. When nodular regrowth was seen at the operative site, the recurrent lesion was radically excised as nodular melanoma. However the histological characteristics of the second excised specimen were essentially the same as those in the initially excised one except for the existence of the newly formed collagen fibers, which may suggest an involuting stage in the central portion of the lesion.
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Affiliation(s)
- K Tanaka
- Department of Dermatology, Tottori University School of Medicine, Yonago, Japan
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608
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Shukuwa T, Nonaka S, Yoshida H. A comparative study of fluorescence in malignant melanoma and nevocellular nevus using a fluorescence microscope and formalin-fixed specimens. J Dermatol 1990; 17:538-44. [PMID: 2277143 DOI: 10.1111/j.1346-8138.1990.tb01691.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fluorescence in malignant melanoma cells was investigated. The specimens from 18 cases of malignant melanoma and 26 cases of nevocellular nevus, which were fixed with formalin and embedded in paraffin wax, were studied by the fluorescence microscopic method. On the fluorescence microscope, the malignant melanoma cells emitted intense fluorescence from the cytoplasm. The nevus cells with large amounts of melanin granules showed moderate fluorescence. The tumor cells of melanoma in situ and nevus cells with few melanin granules emitted little fluorescence. Not only malignant melanoma cells but also nevus cells in the formalin fixed specimens had various degrees of fluorescence. Many cases of malignant melanoma emitted intense fluorescence, but this was rarely found in nevocellular nevus. This method is also useful in differentiating melanoma from nevocellular nevus.
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Affiliation(s)
- T Shukuwa
- Department of Dermatology, Nagasaki University School of Medicine, Japan
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609
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Jastrzebska MM, Stepień K, Wilczok J, Porebska-Budny M, Wilczok T. Semiconductor properties of melanins prepared from catecholamines. Gen Physiol Biophys 1990; 9:373-83. [PMID: 2272486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
D. C. dark - and photoconductivity measurements were performed with synthetic melanins prepared by oxidative polymerization of dopamine, adrenaline, adrenochrome and adrenolutin. The melanins examined show significant differences in conductivity, thermal activation energy and photocurrent intensity values. The differences in semiconductor properties observed between the melanins reflect the structure differences of catecholamine-melanin polymers.
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Affiliation(s)
- M M Jastrzebska
- Department of Biochemistry and Biophysics, Faculty of Pharmacy, Silesian Medical Academy, Sosnowiec, Poland
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610
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Matsunaga TO, Gehrig CA, Hruby VJ. 1H-NMR assignments and conformational studies of melanin concentrating hormone in water using two-dimensional NMR. Biopolymers 1990; 30:1291-5. [PMID: 1964810 DOI: 10.1002/bip.360301314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- T O Matsunaga
- Department of Chemistry, University of Arizona, Tucson 85721
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611
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Sorokulova IB, Reznik SR. [Pigments produced by Bacillus subtilis var. niger 16k]. Prikl Biokhim Mikrobiol 1979; 15:314-7. [PMID: 95833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pigments produced by Bacillus subtilis var. niger 16k on tyrosine agar and histidine containing synthetic medium were isolated and identified. On the basis of a number of tests the pigments were classified as melanins.
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612
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Abstract
The melanin granules of the eye generate a free radical when irradiated with visible light under approximately physiological conditions. The rapid generation in light and decay in dark of the free radical as indicated by electron spin resonance studies, coupled with the anatomical proximity of the melanin granules to the rods and cones of the eye, suggest that these granules may play an important role in the visual process. The investigation of this free radical offers a possible approach to connect the photochemical events in the eye with the subsequent electrophysiological events in the nerve.
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613
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HAGER G. [On the staining of bleached celloidin serial sections]. Mikroskopie 1962; 17:120-6. [PMID: 13903611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
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614
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STAMM MD. [Studies of on the biochemistry of insects. XIV. Metamorphosis hormones in insects]. Rev Esp Fisiol 1962; 18:39-44. [PMID: 13916168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
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615
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616
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MIYAKE M, HATTORI H. [Studies on composition of melanin in living bodies. (Influence of vitamin B1 and B2)]. Nihon Ganka Kiyo 1961; 12:973-6. [PMID: 14474794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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617
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TOMITA T. [Paper electrophoretic studies on rabbit uvea. I. On melanin]. Nippon Ganka Gakkai Zasshi 1961; 65:1049-56. [PMID: 13777337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
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618
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EDWARDS ML, KERKUT GA, MUNDAY KA, LEACH K. Effect of Temperature on the Concentration of Free Radicals in Melanins from Allium cepa. Nature 1961; 190:1005-6. [PMID: 13725813 DOI: 10.1038/1901005a0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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619
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Abstract
SUMMARY
Sections of human skin obtained from a variety of sites and from subjects of different ages have been examined. Mast cells, melanocytes and melanophores have been identified by the use of various staining procedures, but the 'chromaffin cells' reported by Adams-Ray & Nordenstam (1956) and Burch & Phillips (1958) have not been observed. The staining reactions of pressor amine-containing chromaffin cells are reviewed and contrasted with those of the granular cells of the skin.
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620
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CHRISTOMANOS AA. [Spectroscopic and chromatographic studies on the melanoidin proteid of Mytilus edulis, the melanin of Sepia, as well as on pseudomelanin from N-free substances]. Enzymologia 1961; 22:384-92. [PMID: 13693438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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621
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622
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623
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624
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RANGIER M. [On the chemical structure of melanins]. C R Hebd Seances Acad Sci 1959; 249:1954-5. [PMID: 14436179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
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625
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STINSON JC, LEA WA, SUNBURY TR, FORD HC. A rapid technic for demonstrating melanin in fresh tissue. J Invest Dermatol 1959; 33:223-4. [PMID: 13834698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
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626
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PECHAN Z. [Studies on melanin and melanogenesis. III. Evaluation of Thormahlen's reaction for the determination of indole melanogens]. Neoplasma 1959; 6:397-403. [PMID: 14431278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
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627
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