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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Coral Reef Research
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1483206

CONFOCAL LASER SCANNING MICROSCOPY REVEALS SPECIES-SPECIFIC DIFFERENCES IN DISTRIBUTION OF FLUORESCENT PROTEINS IN CORAL TISSUES

Provisionally accepted
Giulia Manso Marchioro Giulia Manso Marchioro 1,2*David Coelho David Coelho 2,3Thibault Bouderlique Thibault Bouderlique 4Daniel Abed-Navandi Daniel Abed-Navandi 5Michael Schagerl Michael Schagerl 1Cecilia D'Angelo Cecilia D'Angelo 6Luise Kruckenhauser Luise Kruckenhauser 1,7Igor Adameyko Igor Adameyko 4,8Pedro R. FRADE Pedro R. FRADE 2,9
  • 1 Vienna Doctoral School of Ecology and Evolution (VDSEE), University of Vienna, Vienna, Austria
  • 2 Zoological Department III, Natural History Museum Vienna, Vienna, Austria
  • 3 University of Algarve, Faro, Faro, Portugal
  • 4 Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
  • 5 Haus des Meeres, Vienna, Austria
  • 6 School of Ocean and Earth Science, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
  • 7 Central Research Laboratories, Natural History Museum Vienna, Vienna, Austria
  • 8 Department of Physiology and Pharmacology, Karolinska Institutet (KI), Stockholm, Stockholm, Sweden
  • 9 Caribbean Research and Management of Biodiversity Foundation, Willemstad, Curaçao

The final, formatted version of the article will be published soon.

    Reef-building corals have a variety of green fluorescent protein (GFP)-like proteins, also known as fluorescent proteins (FPs). These proteins have broad spectral properties covering most of the visible spectrum, with fluorophores fluorescing from cyan to red. However, the role of FPs is still a topic of debate and requires further investigation, particularly in the direction of mapping these FPs within the coral tissue and describing their cell-and tissue-level distributions. This study applied confocal laser scanning microscopy (CLSM) to investigate species-specific differences in the distribution of FPs in three coral taxa (Stylophora sp., Acropora sp., Echinopora sp.), combined with their photoacclimation response and that of associated symbiotic algae to light gradients in a controlled aquarium experiment. CLSM produced high-resolution images that enabled the identification of different FPs, their tissue distribution and quantification of their fluorescence intensity, as well as quantification of symbiont chlorophyll a (chl-a) fluorescence. Emission scans revealed three emission peaks between 490 -501 nm (cyan, CFPs), 510 -515 nm (green, GFPs), and 679 nm (chl-a fluorescence signal; Fchl) shared by all three studied species. The distribution of GFPs in Stylophora was concentrated in the intermesenterial muscle bands of the polyp, whereas CFPs were typically located at the tips of the tentacles. In contrast, Acropora and Echinopora exhibited agglomeration of CFPs and GFPs primarily in the epidermis. In general, species-specific differences in FP distribution remained unaltered during the experiment. However, linear regression models showed a significant negative relationship between CFP fluorescence intensity and light irradiance in Stylophora, whereas Echinopora exhibited a negative relation between chlorophyll fluorescence (Fchl) and light. In summary, the CLSM methodology provided a high-resolution tool to study coral FP patterns and symbiont response to irradiance, revealing ecophysiological differences among coral species at a tissue and cellular level. CLSM has the potential to elucidate the intricacies of coral photobiology within the natural environment and to discern their adaptive responses in situ.

    Keywords: photoacclimation, confocal microscopy, fluorescence, GFP-like protein, photosynthesis the high-light treatment Font: Italic

    Received: 19 Aug 2024; Accepted: 28 Oct 2024.

    Copyright: © 2024 Manso Marchioro, Coelho, Bouderlique, Abed-Navandi, Schagerl, D'Angelo, Kruckenhauser, Adameyko and R. FRADE. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Giulia Manso Marchioro, Vienna Doctoral School of Ecology and Evolution (VDSEE), University of Vienna, Vienna, Austria

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.