Journal article
Oxygen Radical Production in the Sea Anemone Anthopleura Elegantissima and its Endosymbiotic Algae
Journal of experimental biology, Vol.168(1), pp.219-241
07/01/1992
DOI: 10.1242/jeb.168.1.219
Abstract
Host animals in algal-invertebrate endosymbiotic associations are exposed to photosynthetically generated hyperoxia while in sunlight, conditions conducive to photodynamic excitations and production of cytotoxic oxygen-derived radicals such as the superoxide anion (O2−) and the hydroxyl radical (OH). All previous vidence of oxyradical production in symbiotic associations has been circumstantial. We here present direct evidence, from electron paramagnetic resonance studies on tissue homogenates of the photosymbiont-containing sea anemone Anthopleura elegantissima (Brandt), of substantial light-dependent OH and O2 production that is abolished by dichlorophenyldimethylurea (DCMU), an inhibitor of photosynthesis. Shade-adapted A. elegantissima lacking endosymbiotic algae likewise show OH production upon illumination. The latter flux is not dependent on photosynthesis, and DCMU has no effect. Rather, OH production in apozooxanthellate anemones is via direct photoexcitations. The selective reaction of dimethyl sulfoxide (DMSO) with OH to form methane sulfinic acid allows quantification of OH produced in vivo. Such in vivo measurements confirm the production of OH in both host and algae in illuminated zooxanthellate anemones, where the amount of OH in the zooxanthellae is disproportionately large relative to their fractional contribution to the biomass of the symbiosis. In vivo studies using DMSO also suggest a photochemical production of OH in apozooxanthellate anemones exposed to simulated sunlight enriched in ultraviolet (UV) wavelengths, and the enhancement by UV light of OH production in zooxanthellate individuals. Such chronic radical exposure necessitates defenses
Details
- Title: Subtitle
- Oxygen Radical Production in the Sea Anemone Anthopleura Elegantissima and its Endosymbiotic Algae
- Creators
- JAMES A. Dykens - Grinnell CollegeJ. MALCOLM Shick - University of MaineCRAIG Benoit - Louisiana State UniversityGARRY R. Buettner - University of IowaGARY W. Winston - Louisiana State University
- Resource Type
- Journal article
- Publication Details
- Journal of experimental biology, Vol.168(1), pp.219-241
- DOI
- 10.1242/jeb.168.1.219
- ISSN
- 0022-0949
- eISSN
- 1477-9145
- Language
- English
- Date published
- 07/01/1992
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984314276902771
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