Ockham's razor gone blunt: coenzyme Q adaptation and redox balance in tropical reef fishes |
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Authors: | Monica Gagliano Walter C Dunlap Rocky de Nys Martial Depczynski |
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Institution: | 1.School of Marine Biology, James Cook University, Townsville, Queensland 4811, Australia;2.Australian Institute of Marine Science, PMB3, Townsville, Queensland 4810, Australia;3.Australian Institute of Marine Science, University of Western Australia (M096), Crawley, Western Australia 6009, Australia |
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Abstract: | The ubiquitous coenzyme Q (CoQ) is a powerful antioxidant defence against cellular oxidative damage. In fishes, differences in the isoprenoid length of CoQ and its associated antioxidant efficacy have been proposed as an adaptation to different thermal environments. Here, we examine this broad contention by a comparison of the CoQ composition and its redox status in a range of coral reef fishes. Contrary to expectations, most species possessed CoQ8 and their hepatic redox balance was mostly found in the reduced form. These elevated concentrations of the ubiquinol antioxidant are indicative of a high level of protection required against oxidative stress. We propose that, in contrast to the current paradigm, CoQ variation in coral reef fishes is not a generalized adaptation to thermal conditions, but reflects species-specific ecological habits and physiological constraints associated with oxygen demand. |
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Keywords: | coenzyme Q fishes redox balance temperature |
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