Corals make use of different chemical compounds during interactions with prey, predators and aggressors. Hydrogen Peroxide (H2O2) is produced and released by a wide range of organisms as part of their defense against grazers or pathogens. In coral reefs, the large fluxes and relatively long half-life of H2O2, make it a potentially important info-chemical or defense molecule. Here we describe a previously unstudied phenomenon of rapid H2O2 release from the reef-building coral Stylophora pistillata during feeding on zooplankton and in response to chemical and physical stimuli. Following stimuli, both symbiotic and bleached corals were found to rapidly release H2O2 to the surrounding water for a short period of time (few minutes). The H2O2 release was restricted to the site of stimulus, and an increase in physical stress and chemical stimuli concentration resulted in elevated H2O2 release. Omission of calcium (a key regulator of exocytotic processes) from the experimental medium inhibited H2O2 release. Hence we suggest that H2O2 is actively released in response to stimuli, rather than leaking passively from the coral tissue. We estimate that at the site of stimulus H2O2 can reach concentrations potentially high enough to deter predators or motile, potentially pathogenic, bacteria.
|State||Published - 15 Feb 2016|
Bibliographical noteFunding Information:
We wish to thank Murielle Dray, Yaron Halevy, Bastian Piltz and Itay Cohen for their assistance with the lab work and Tamar Lotan, Eugene Rosenberg and Ariel Kushmaro for their good advice and helpful discussions. We also thank two referees for very thoughtful and helpful remarks. This study was supported by Israel Science Foundation grant number 248/11 to YS and 1239/13 to DS (www.isf.org.il).
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