Somatic and skeletally fixed carotenoids of t he purple hydrocoral, Allopora californica

Fox, Denis L.; Wilkie, Donald W.

doi:10.1016/0010-406x(70)90649-3

Cited by 26 publications

(5 citation statements)

References 9 publications

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“…Each of the species analysed presented a more or less distinct change of colour due to the presence of euendoliths inside their coral skeleton, as compared with their regular colour when they are not infested (Figure 4; Table I). Stylasterids are usually bright-coloured colonies due to their own pigments (Fox & Wilkie 1970;Fox 1972Fox , 1976. The occurrence of pigmented (phototrophic) euendoliths inside their coenosteum modifies the original colour of infested parts of the skeleton.…”

Section: Discussionmentioning

confidence: 99%

Microboring organisms in living stylasterid corals (Cnidaria, Hydrozoa)

Pica

Tribollet

Golubić

et al. 2016

Marine Biology Research

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Microboring or euendolithic microorganisms, which colonize and penetrate various carbonate substrates, are abundant in coral reef ecosystems and play a major role in reef carbonate dissolution. A few studies reported the presence of euendoliths in stylasterid coral skeletons but the biological identity, distribution and abundance of these microorganisms remain largely unknown. Observations of over 100 stylasterid colonies, collected in the Indo-Pacific area, revealed for the first time that the association between these corals and euendolith organisms appears to be quite common in shallow tropical waters. The most abundant euendolith was identified as a cryptic stage in the development of the rhodophyte Porphyra (Conchocelis stage). The euendoliths were observed in the skeletons of seven species of three genera (four Stylaster, two Distichopora and one Lepidotheca). The presence of euendoliths inside skeletons conferred a particular colour to the studied stylasterid corals. Distribution and abundance of microborings varied significantly among stylasterid species and among branches of a single colony and so did the colour of their skeletons. Colonization of skeletons and the associated colour distribution were almost uniform in some stylasterids, forming an upward gradually diminishing or sharply limited gradient. This study shows that patterns of euendolith colonization and growth in stylasterid skeletons may depend on the stage of the euendolith development as well as on their environmental requirements such as light exposure

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Section: Discussionmentioning

confidence: 99%

Microboring organisms in living stylasterid corals (Cnidaria, Hydrozoa)

Pica

Tribollet

Golubić

et al. 2016

Marine Biology Research

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“…Carotenoid molecules contain a polyenic chain, however there are four additional methyl groups substituted on this chain. Pigments containing polyenic chains are widespread in nature, for example in phytoplankton (Hoskins & Alexander, 1977), coral polyps and mollusk shells (Fox & Wilkie, 1970;Merlin & Delé-Dubois, 1983;Merlin, 1985;Merlin & Delé-Dubois, 1986;Vershinin, 1996;Barnard & De Waal, 2006;Hedegaard et al, 2006), vegetables (tomatoes, carrots etc. ; Withnall et al, 2003), bird feathers (Stradi et al, 1995(Stradi et al, , 1996(Stradi et al, , 2001aVeronelli et al, 1995), human retina (Ermakov et al, 2005), etc.…”

Section: Introductionmentioning

confidence: 99%

Role of polyenes in the coloration of cultured freshwater pearls

Karampelas

Fritsch

Mevellec

et al. 2009

ejm

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The exact nature of pigments present in cultured freshwater pearls is still not well known. We examined 21 untreated cultured freshwater pearls from Hyriopsis of typical colors by diffuse reflectance UV-Vis-NIR and Raman scattering measurements, at high resolution. The objective was to establish the relation between color and the nature of the pigment mixture in pearls, using strictly non-destructive methods. All natural color samples show the two major Raman resonance features of unmethylated (unsubstituted) polyenes, not carotenoids. Their general chemical formulae are R-(-CH¼CH) N-R 0 with N ¼ 6 to 14 and they give absorptions from violet to yellow-green. Each color is due to a mixture of pigments, not a single pigment. Different colors are explained by different mixtures. Each pigment identified by Raman spectroscopy can be related to a specific absorption with apparent maximum in the range 405-568 nm, thus absorbing from violet to yellow-green. This is the first study of the precise relation between Raman and diffuse reflectance spectra of cultured freshwater pearls.

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“…Prominent among such colored compounds or substances are melanins, tetrapyroles, hydroxynaphtoquinones and fat-soluble lipochromic polyenes. 8 Polyenes are polyunsaturated organic compounds that contain one or more sequences of alternating double and single carbon-carbon bonds (polyenic chain). Pigments containing polyenic chains are widespread in nature.…”

Section: Introductionmentioning

confidence: 99%

Determination by Raman scattering of the nature of pigments in cultured freshwater pearls from the mollusk Hyriopsis cumingi

Karampelas¹,

Fritsch²,

Mevellec³

et al. 2006

J Raman Spectroscopy

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The nature of pigments in naturally colored pearls is still under discussion. For this study, Raman scattering measurements were obtained for 30 untreated freshwater cultured pearls from the mollusk Hyriopsis cumingi covering their typical range of colors. The originality of this work is that seven different excitation wavelengths (1064 nm, 676.44 nm, 647.14 nm, 514.53 nm, 487.98 nm, 457.94 nm, 363.80 nm) are used for the same samples at the highest possible resolution. All colored pearls show the two major Raman features of polyenic compounds assigned to double carbon-carbon (C C) -at about 1500 cm −1 -and single carbon-carbon (C-C) -at about 1130 cm −1 -bond stretching mode, regardless of their specific hue. These peaks are not detected in the corresponding white pearls, and therefore seem directly related to the major cause of body color. Additionally, the exact position of C C stretching vibration shows that these compounds are not members of the carotenoid family. Moreover, some changes are observed in intensities, shape and positions of the two main characteristic polyenic peaks from one sample to the next. Similar changes are observed also using several excitation wavelengths for the same point of the same pearl. The exact position of C-C stretching vibration of polyenic molecules depends strongly on the number of double bonds (N) contained in their polyenic chain. Hence, using a constrained decomposition of this band for different excitation wavelengths, up to nine different pigments may be detected in the same pearl. Their general chemical formula is R-(-CH CH-) N -R with N = 6-14. All our colored samples contained at least four pigments (N = 8-11). Different colors are explained by different mixtures, not by a simple change of pigment. The chemical nature of the chain ends is still unknown, because it cannot be detected with Raman scattering. However, it is possible that these polyenes are complexed with carbonate molecules of the nacre. Similar coloration mechanisms are found in products from other living organisms (e.g. parrots feathers). Moreover, it seems that a similar series of pigments is found in other pearls also, as well as in some marine animals living in similar environments (e.g. corals).

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Somatic and skeletally fixed carotenoids of t he purple hydrocoral, Allopora californica

Cited by 26 publications

References 9 publications

Microboring organisms in living stylasterid corals (Cnidaria, Hydrozoa)

Microboring organisms in living stylasterid corals (Cnidaria, Hydrozoa)

Role of polyenes in the coloration of cultured freshwater pearls

Determination by Raman scattering of the nature of pigments in cultured freshwater pearls from the mollusk Hyriopsis cumingi

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