Fluorescence color diversity of great barrier reef corals

Grigory Lapshin,Victor Bagratashvili,Leonid Vinokurov,Peter Kolosov,Tatyana Ivashina,Alexander Savitsky,Yuri Zavorotnyi,Anya Salih,Maria Golovkina

doi:10.1142/s1793545815500285

Abstract

A group of variously colored proteins belonging to the green fluorescent protein (GFP) family are responsible for coloring coral tissues. Corals of the Great Barrier Reef were studied with the custom-built fiber laser fluorescence spectrometers. Spectral analysis showed that most of the examined corals contained multiple fluorescent peaks ranging from 470 to 620 nm. This observation was attributed to the presence of multiple genes of GFP-like proteins in a single coral, as well as by the photo-induced post-translational modifications of certain GFP-like proteins. We isolated a novel photo-convertible fluorescent protein (FP) from one of the tested corals. We propose that two processes may explain the observed diversity of the fluorescent spectra in corals: (1) dark post-translational modification (maturation), and (2) color photo-conversion of certain maturated proteins in response to sunlight.

Highlights

The color diversity of the Great Barrier Reef ecosystem in general, and its °uorescence color diversity specically, is surprising
The present study reveals the characteristics of the °uorescence spectra of several species and color morphs of corals from the Great Barrier Reef
Screening of scleractinian corals for °uorescence was done in situ, underwater, using blue light torches (Night Sea Inc) as described previously[12] at Heron Island and One Tree Island located in the center of the Capricorn Group of the Great Barrier Reef and $ 100 km o® the Queensland coast, Australia

Summary

Introduction

The color diversity of the Great Barrier Reef ecosystem in general, and its °uorescence color diversity specically, is surprising. At the same time the functional role of such diversity remains largely unknown.[1] The natural pallet of coral colors is limited by coral host tissue pigments and by the natural brown color of photosynthetic pigments (chlorophyll a and c2, peridinin) of the endosymbiotic zooxanthellae. Coral host-specic pigments °uoresce under visible light or UV excitation,[2] while red emissions at 680 nm arise from chlorophylls of zooxanthellae. The unusual feature of GFP protein superfamily is that, in contrast to most other pigments, the GFP-like proteins do not require any cofactors or prosthetic groups for autocatalytic chromophore formation.[6,7] it is well known that the GFP-like proteins are responsible for the °uorescent colors of corals, and for their non°uorescent blue, pink and purple hues.[6,8]

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Conclusion