Dataset Information

Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

ABSTRACT:

Background

Reactive oxygen species (ROS) are thought to play a major role in cell death pathways and bleaching in scleractinian corals. Direct measurements of ROS in corals are conspicuously in short supply, partly due to inherent problems with ROS quantification in cellular systems.

Methodology/principal findings

In this study we characterized the dynamics of the reactive oxygen species superoxide anion radical (O(2)(-)) in the external milieu of the coral Stylophora pistillata. Using a sensitive, rapid and selective chemiluminescence-based technique, we measured extracellular superoxide production and detoxification activity of symbiont (non-bleached) and aposymbiont (bleached) corals, and of cultured Symbiodinium (from clades A and C). Bleached and non-bleached Stylophora fragments were found to produce superoxide at comparable rates of 10(-11)-10(-9) mol O(2)(-) mg protein(-1) min(-1) in the dark. In the light, a two-fold enhancement in O(2)(-) production rates was observed in non-bleached corals, but not in bleached corals. Cultured Symbiodinium produced superoxide in the dark at a rate of . Light was found to markedly enhance O(2)(-) production. The NADPH Oxidase inhibitor Diphenyleneiodonium chloride (DPI) strongly inhibited O(2)(-) production by corals (and more moderately by algae), possibly suggesting an involvement of NADPH Oxidase in the process. An extracellular O(2)(-) detoxifying activity was found for bleached and non-bleached Stylophora but not for Symbiodinium. The O(2)(-) detoxifying activity was partially characterized and found to resemble that of the enzyme superoxide dismutase (SOD).

Conclusions/significance

The findings of substantial extracellular O(2)(-) production as well as extracellular O(2)(-) detoxifying activity may shed light on the chemical interactions between the symbiont and its host and between the coral and its environment. Superoxide production by Symbiodinium possibly implies that algal bearing corals are more susceptible to an internal build-up of O(2)(-), which may in turn be linked to oxidative stress mediated bleaching.

SUBMITTER: Saragosti E

PROVIDER: S-EPMC2939047 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

Saragosti Eldad E Tchernov Dan D Katsir Adi A Shaked Yeala Y

PloS one 20100914 9

<h4>Background</h4>Reactive oxygen species (ROS) are thought to play a major role in cell death pathways and bleaching in scleractinian corals. Direct measurements of ROS in corals are conspicuously in short supply, partly due to inherent problems with ROS quantification in cellular systems.<h4>Methodology/principal findings</h4>In this study we characterized the dynamics of the reactive oxygen species superoxide anion radical (O(2)(-)) in the external milieu of the coral Stylophora pistillata. ...[more]

PMID: 20856857

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Project description:Energy sources of corals, ultimately sunlight and plankton availability, change dramatically from shallow to mesophotic (30-150 m) reefs. Depth-generalist corals, those that occupy both of these two distinct ecosystems, are adapted to cope with such extremely diverse conditions. In this study, we investigated the trophic strategy of the depth-generalist hermatypic coral Stylophora pistillata and the ability of mesophotic colonies to adapt to shallow reefs. We compared symbiont genera composition, photosynthetic traits and the holobiont trophic position and carbon sources, calculated from amino acids compound-specific stable isotope analysis (AA-CSIA), of shallow, mesophotic and translocated corals. This species harbors different Symbiodiniaceae genera at the two depths: Cladocopium goreaui (dominant in mesophotic colonies) and Symbiodinium microadriaticum (dominant in shallow colonies) with a limited change after transplantation. This allowed us to determine which traits stem from hosting different symbiont species compositions across the depth gradient. Calculation of holobiont trophic position based on amino acid δ15N revealed that heterotrophy represents the same portion of the total energy budget in both depths, in contrast to the dogma that predation is higher in corals growing in low light conditions. Photosynthesis is the major carbon source to corals growing at both depths, but the photosynthetic rate is higher in the shallow reef corals, implicating both higher energy consumption and higher predation rate in the shallow habitat. In the corals transplanted from deep to shallow reef, we observed extensive photo-acclimation by the Symbiodiniaceae cells, including substantial cellular morphological modifications, increased cellular chlorophyll a, lower antennae to photosystems ratios and carbon signature similar to the local shallow colonies. In contrast, non-photochemical quenching remains low and does not increase to cope with the high light regime of the shallow reef. Furthermore, host acclimation is much slower in these deep-to-shallow transplanted corals as evident from the lower trophic position and tissue density compared to the shallow-water corals, even after long-term transplantation (18 months). Our results suggest that while mesophotic reefs could serve as a potential refuge for shallow corals, the transition is complex, as even after a year and a half the acclimation is only partial.

Dataset Information

Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

Background

Methodology/principal findings

Conclusions/significance

Publications

Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

Similar Datasets

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