Chapter 6 Chemistry of Melanins

Crippa, Raimondo; Horák, V.; Prota, Giuseppe; Svoronos, Paris D N; Wolfram, L. J.

doi:10.1016/s0099-9598(08)60085-1

Cited by 31 publications

(35 citation statements)

References 211 publications

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“…The vibrational bands observed for BIOM and WIOM are the same, and coincide with many of those of natural and synthetic melanins noted by Crippa et al (1989). Some of the bands are not specific to melanins, but rather to glycoproteins (amine and amide bands, COOH-carboxylate, sugars).…”

Section: Infrared Studysupporting

confidence: 75%

“…No such melanin patches have been recorded in the external epithelium of the mantle of brown shells. According to this observation and their different solubility (Crippa et al, 1989), the two melanin pigments, phaeomelm nin in the mantle and eumelanin in the shell, are considered to have different origins and to be unrelated.…”

Section: Discussionmentioning

confidence: 99%

“…The appearance of the brown compound in scallop shells is characterized by the same reflectance and absorbency properties in the visible range: a monotonic increase of the absorbency with decreasing wavelength which was recorded by Crippa et al (1989) as "the typical spectra of both eu-and phaeomelanin". The extension of the spectral range to the UV in the second method shows that the presence of the organic shell matrix induces interferences linked to the absorption of its proteic component.…”

Section: Spectrometric Studymentioning

confidence: 95%

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Abnormal melanization and microstructural distortions of the shell of great scallop living in shallow water

1996

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Modifications of great scallop (Pecten maximus) shells have been noticed in many sites of scallop fisheries in Brittany, especially in shallow waters. These calcification abnormalities are linked to the appearance of a brown colouration of the internal calcified shell layer, due to the presence of a eumelanin associated with the insoluble organic matrix of the biocrystals. The appearance of this pigment generates many disturbances of the calcified foliated microstructure of the scallop internal shell layer. The mantle structure is not modified in brown shells as compared with white ones. No pathogenic signs such as hyperplasia or haemocytic infiltration have been observed. According to this observation, we hypothesize that the brown colour phenomenon is more a result of environmental disturbance rather than a symptom of a pathogenic disease.The colour abnormalities of the internal shell layer can be detected by a spectral analysis of its reflectance before it can be detected with the naked eye. This method, correlated to microstructural observations, gives a rapid and precise analysis of the appearance of the pigmentation on adult or juvenile scallops. It may be a useful method for the evaluation of the influence of environmental parameters, for example, on calcification and its abnormalities.

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Section: Infrared Studysupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Spectrometric Studymentioning

confidence: 95%

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Abnormal melanization and microstructural distortions of the shell of great scallop living in shallow water

1996

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“…24 Investigations on melanin structure have been carried out either by analytical or biosynthetic approaches. In particular, Nicolaus' explored a number of characterizing methods for natural and synthetic melanins based on their elemental composition, functional groups and structural features.…”

Section: Resultsmentioning

confidence: 99%

Laser desorption ionization mass spectrometry in the study of natural and synthetic melanins. I—Tyrosine melanins

Seraglia

Traldi

Elli³

et al. 1993

Biol. Mass Spectrom.

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Nine synthetic, biosynthetic and natural tyrosine melanins, together with dopa and catechol melanins, have been studied by means of laser desorption ionization mass spectrometry. The results obtained have shown that all the melanins under study consist of homogeneous sets of oligomers and have led to definitive information on their molecular weight distribution (from 500 to 30,000 Da). A deeper analysis of the spectra, in terms of mass differences among the various oligomers, allowed the identification of some monomeric units, identical or analogous to those already proposed in the literature.

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“…From the chemical point of view, the only common feature of microbial melanins is it being a product of oxidative polymerization of various phenolic substances (Przemyslaw and Maja, 2006). Melanins are heterogeneous polymers of dihydroxyindole (DHI) and dihydroxyindole carboxylic acid (DHICA) monomers linked by heterogeneous non-hydrolizable bonds (Crippa, 1989), with only a short-distance ordering .…”

Section: Article Infomentioning

confidence: 99%

Production, Extraction and Partial Purification of Melanin Pigment from Pathogenic Klebsiella pneumoniae HM Isolated from Clinical Samples

Saud¹,

Alaubydi²

2016

Int.J.Curr.Microbiol.App.Sci

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Chapter 6 Chemistry of Melanins

Cited by 31 publications

References 211 publications

Abnormal melanization and microstructural distortions of the shell of great scallop living in shallow water

Abnormal melanization and microstructural distortions of the shell of great scallop living in shallow water

Laser desorption ionization mass spectrometry in the study of natural and synthetic melanins. I—Tyrosine melanins

Production, Extraction and Partial Purification of Melanin Pigment from Pathogenic Klebsiella pneumoniae HM Isolated from Clinical Samples

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