Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy

Galván, Ismael; Jorge, Alberto; Solano, Francisco; Wakamatsu, Kazumasa

doi:10.1016/j.saa.2013.03.027

Cited by 36 publications

(52 citation statements)

References 35 publications

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“…(2013a)), and the wide Raman bands at about 500, 1490, and 2000 cm −1 characteristic of pheomelanin (Galván et al. 2013b), the spectra reported by Thomas et al. (2013) all exhibited a sinusoidal disturbance characteristic of fluorescence in the range 300–1600 cm −1 irrespective of the melanin type present in the feather (i.e., no difference was reported between eumelanin and pheomelanin) (Fig 1…”

Section: Resultsmentioning

confidence: 87%

“…We obtained the previously reported characteristic Raman spectra for eumelanin and pheomelanin (Galván et al. 2013a,b) in the species in which Thomas et al. (2013) expected to find either eumelanin or pheomelanin, respectively, based on the color of feathers.…”

Section: Resultsmentioning

confidence: 97%

“…This method has been proved efficient at distinguishing eumelanin and pheomelanin when both melanin forms are mixed in the focal tissues, as it usually happens (Galván et al. 2013a,b). We also analyzed a barb of an unpigmented feather of a white Gyrfalcon Falco rusticolus as a control, as the Raman signal from keratin (the main compound in nonpigmented feathers; Hsu et al.…”

Section: Methodsmentioning

confidence: 99%

“…(2013) conflict with the ones reported by Galván et al. (2013b), who characterized the Raman spectrum of pheomelanin, again not including fluorescence but wide Raman bands at about 500, 1490, and 2000 cm −1 (Galván et al. 2013b).…”

Section: Introductionmentioning

confidence: 99%

“…(2013b), who characterized the Raman spectrum of pheomelanin, again not including fluorescence but wide Raman bands at about 500, 1490, and 2000 cm −1 (Galván et al. 2013b). This Raman spectrum can also be detected from pheomelanin embedded in feathers (Galván et al.…”

Section: Introductionmentioning

confidence: 99%

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Dispersive Raman spectroscopy allows the identification and quantification of melanin types

Galván

Jorge

2015

Ecology and Evolution

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Melanins are the most prevalent pigments in animals and are involved in visual communication by producing colored traits that often evolve as intraspecific signals of quality. Identifying and quantifying melanins are therefore essential to understand the function and evolution of melanin-based signals. However, the analysis of melanins is difficult due to their insolubility and the lack of simple methods that allow the identification of their chemical forms. We recently proposed the use of Raman spectroscopy as a simple, noninvasive technique that can be used to identify and quantify melanins in feathers and hairs. Contrarily, other authors later stated that melanins are characterized by a lack of defined Raman signals. Here, we use confocal Raman microscopy to confirm previous analyses showing that the two main chemical forms of melanins (eumelanin and pheomelanin) exhibit distinct Raman signal and compare different excitation wavelengths to analyze synthetic pheomelanin and natural melanins in feathers of different species of birds. Our analyses indicate that only laser excitation wavelengths below 1064 nm are useful for the analysis of melanins by Raman spectroscopy, and only 780-nm laser in the case of melanins in feathers. These findings show that the capacity of Raman spectroscopy to distinguish different chemical forms of melanins depends on laser power and integration time. As a consequence, Raman spectroscopy should be applied after preliminar analyses using a range of these parameters, especially in fragile biological tissues such as feathers.

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Section: Resultsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dispersive Raman spectroscopy allows the identification and quantification of melanin types

Galván

Jorge

2015

Ecology and Evolution

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Colour in bivalve shells: Using resonance Raman spectroscopy to compare pigments at different phylogenetic levels

Wade

Pugh

Nightingale

et al. 2019

J Raman Spectroscopy

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Several studies have suggested that shell colour may be phylogenetically distributed within the phylum Mollusca, but this pattern is confounded by our ignorance of the homology of colour and lack of understanding about the identity of most molluscan pigments. We use resonance Raman spectroscopy to address this problem by examining bivalve pigments producing a range of colours and compare spectra from taxa at different phylogenetic levels. The spectra of most shell pigments exhibited a skeletal signature typical of partially methylated polyenes, possibly modified carotenoids, with the strongest peaks occurring between 1,501–1,540 cm−1 and 1,117–1,144 cm−1 due to the C═C (ν1) and C–C (ν2) stretching modes, respectively. Neither pigment class nor mineral structure differentiated Imparidentia and Pteriomorphia. Spectral acquisitions for purple pigments for two species of Asaphis suggest that identical or nearly identical pigments are shared within this genus, and some red pigments from distantly related species have similar spectra. Conversely, two species with brown shells have distinctly different pigments, highlighting the difficulty in determining the homology of colour even within a single class of pigments. Curiously, we were unable to detect any Raman activity for green‐coloured shell or pigment peaks for the yellow area of Codakia paytenorum, suggesting that these colours are due to structural elements or a pigment that is quite different from those observed in other taxa examined to date. Our results are consistent with the idea that classes of pigments are evolutionarily ancient but heritable modifications may be specific to clades.

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Extraction, Purification, and Characterization of Microbial Melanin Pigments

Ghadge

Singh

Kumar

et al. 2023

Melanins: Functions, Biotechnological Production, and Applications

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Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy

Cited by 36 publications

References 35 publications

Dispersive Raman spectroscopy allows the identification and quantification of melanin types

Dispersive Raman spectroscopy allows the identification and quantification of melanin types

Colour in bivalve shells: Using resonance Raman spectroscopy to compare pigments at different phylogenetic levels

Extraction, Purification, and Characterization of Microbial Melanin Pigments

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