Oxidative biomarkers as indicators of reproductive effects in Daphnia magna
(English)Manuscript (preprint) (Other academic)
Oxidative stress can be induced by various stressors, and oxidative biomarkers are commonly used as indicators of xenobiotic exposure. However, the capacity of oxidative biomarkers to predict pro-oxidative exposure or indicate reproductive effects has not been evaluated. In this study, we hypothesized that biomarkers of oxidative stress (catalase, antioxidant capacity, and lipid peroxidation) can be used to diagnose pro-oxidative exposure, with concomitant reproductive penalties. We exposed Daphnia magna to UVB irradiation, a known agent inducing pro-oxidative processes in various organisms, from birth to adult stage. The biomarker responses were followed in different life-stages in concert with reproductive success and individual growth rate. The UVB exposure induced alterations in antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC) in both juvenile and adult daphnids. Moreover, these effects were age-specific, with decreased and increased ORAC in juveniles and adults, respectively. These changes were associated with reproductive success, as increased number of offspring was negatively associated with antioxidant capacity. Also, a trans-generational effect was observed as exposed females allocated less antioxidants to their offspring. ORAC normalized to protein content (ORACp) was identified as a suitable biomarker of pro-oxidative exposure. For diagnostics of oxidative stress in field and laboratory settings, two logistic models employing ORACp in juvenile and adult D. magna were proposed; the classification accuracy of the models was about 80%. None of the other biomarkers contributed significantly to the models.
Oxidative stress, reproduction, UVB, oxygen rdaical absorbance capacity
Research subject Applied Environmental Science
IdentifiersURN: urn:nbn:se:su:diva-120209OAI: oai:DiVA.org:su-120209DiVA: diva2:852596