These Colors Don’t Run: Regulation of Pigment—Biosynthesis in Echinoderms

Abstract

Pigment production is an important biological process throughout the tree of life. Some pigments function for collecting light energy, or for visual identification, while others have dramatic antimicrobial functions, or camouflage capabilities. The functions of these pigments and their biosynthesis are of great interest if only because of their diversity. The biochemistry of echinoderm pigmentation has been intensively studied for many years, and with more recent technologies, the origin and functions of these pigments are being exposed. Here we summarize the major pigment types in biology and emphasize the status of the field in echinoderms, taking full advantage of the new genomic and technologic resources for studying these important animals and their beautiful pigmentation.

A Cytotoxic Porphyrin from North Pacific Brittle Star Ophiura sarsii

“…Porphyrins have been identified in several marine living organisms including Echinodermata [ 13 ]. However, they were not seen, and were considered absent, in the class of Ophiuroidea [ 11 , 12 ].…”

“…While possessing a strong anti-Wnt activity (to be described in detail in a separate article), the extracts also revealed a separate potent cytotoxic activity, which surprisingly was found to be mediated by a porphyrin compound. Not previously identified in the class Ophiuroidea [ 11 , 12 , 13 ], synthetic porphyrins have found wide applications in the photodynamic therapy (PDT). Our findings may have identified a natural photosensitizer for future PDT applications.…”

Chlorin Endogenous to the North Pacific Brittle Star Ophiura sarsii for Photodynamic Therapy Applications in Breast Cancer and Glioblastoma Models

“…Although known in some marine invertebrates including some Echinodermata such as the sea urchin Strongylocentrotus purpuratus [ 8 ], porphyrins were considered absent in the class of Ophiuroidea [ 11 ]. Thus, following our discovery of ETPA in Ophiura sarsii , we hypothesized that this chlorin compound could be derived from a food source—perhaps a seasonal one—of these brittle stars [ 10 ].…”

“…Natural products have always been one of the major sources of new drugs, including oncology therapeutics [ 5 , 6 , 7 ]. Porphyrin-type compounds such as chlorins can act as efficient photosensitizers and have been found in diverse living groups [ 4 , 8 ]. In a search for novel anticancer compounds from ophiuras [ 9 ], we have recently discovered the chlorin (3 S ,4 S )-14-Ethyl-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid (ETPA) from a North Pacific brittle star Ophiura sarsii —the first-ever porphyrin identified in Ophiuroidea (phylum Echinodermata) [ 10 ].…”

The Diversity of Linear Conjugated Polyenes and Colours in Nature: Raman Spectroscopy as a Diagnostic Tool

“…An important clue is provided by the incorporation of polyenals into the outer shell layer of the mollusc A. islandica , which has been demonstrated by the Raman spectroscopies analyses of the growth lines [78] . Pks genes isolated from sea urchins [198] showed that PKSs involving domains leading to cyclisation is responsible for the synthesis of the dark‐red echinochrome (naphthoquinone) pigmentation present in their shells as well as spines, eggs, larvae and, adult organisms [199] …”