Effect of mercury and Gpi-2 genotype on standard metabolic rate of eastern mosquitofish (Gambusia holbrooki).
Previous studies demonstrated differential mortality among mosquitofish of different Gpi-2 genotypes during acute mercury and arsenate exposures. Mercury-exposed mosquitofish also had Gpi-2 genotype-specific differences in glycolytic and Krebs cycle metabolite pools. The mortality and metabolite data suggested that mosquitofish bearing specific Gpi-2 genotypes might differ in metabolic efficiency, with less efficient Gpi-2 genotypes having higher standard metabolic rates (SMRs) and shorter times to death during acute mercury exposure. Effect of Gpi-2 genotype on SMR was assessed with a factorial arrangement of six Gpi-2 genotypes and two exposure sequences (Control - Control; Control - 100 microg/L Hg). The SMRs were estimated by measuring oxygen consumption using an indirect, closed-circuit, computer-controlled respirometer. A 48-h exposure to 100 microg/L of mercury resulted in a 16.7% elevation of SMR above control levels (p = 0.001). The Gpi-2 genotype and the number of heterozygous loci per individual had no significant effect on SMR in mercury-exposed mosquitofish. The experimental results do not support the hypothesis that Gpi-2 genotype-specific differences in glycolytic and Krebs cycle metabolite pools and mortality in mosquitofish exposed to mercury are associated with differences in SMR.
Tatara
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National Marine Fisheries Service, Santa Rosa, California 95404, USA. chris.p.tatara@NOAA.gov
Newman
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Mulvey
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D000818:Animals; D000830:Animals, Laboratory; D003433:Crosses, Genetic; D003532:Cyprinodontiformes / Q000235:genetics / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D005838:Genotype; D005956:Glucose-6-Phosphate Isomerase / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D007527:Isoenzymes / Q000235:genetics; D008297:Male; D008628:Mercury / Q000633:toxicity*; D015656:Respiratory Mechanics / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D007527:Isoenzymes; D014874:Water Pollutants, Chemical; D005956:Glucose-6-Phosphate Isomerase; D008628:Mercury