Lister Kathryn N, Lamare Miles D, Burritt David J
Department of Botany, University of Otago, PO Box 56, Dunedin 9016, New Zealand; Department of Marine Science, University of Otago, PO Box 56, Dunedin 9016, New Zealand.
Department of Marine Science, University of Otago, PO Box 56, Dunedin 9016, New Zealand.
Aquat Toxicol. 2015 Apr;161:61-72. doi: 10.1016/j.aquatox.2015.01.031. Epub 2015 Feb 2.
Legacy pollutants, including polycyclic aromatic hydrocarbons (PAHs) and metals, can occur in high concentrations in some Antarctic marine environments, particularly near scientific research stations. Oxidative stress is an important unifying feature underlying the toxicity of many chemical contaminants to aquatic organisms. However, the potential impacts of pollutants on the oxidative physiology of Antarctic marine invertebrates are not well documented. Sterechinus neumayeri is a common animal in the shallow subtidal benthos surrounding Antarctica, and is considered an important keystone species. The aim of the present study was to collect baseline oxidative biomarker data for S. neumayeri and to investigate the impacts of field exposure to chemical contaminants on gamete health and parent-to-offspring transfer of oxidative stress resilience. We analysed antioxidant enzyme activities, levels of the molecular antioxidant glutathione, protein carbonylation, lipid peroxidation and levels of 8-OHdG as oxidative stress biomarkers in S. neumayeri from a contaminant-impacted site near McMurdo Station and a relatively pristine site at Cape Evans. Biomarkers were analysed in adult gamete tissue and in early stage embryos exposed to AN8 fuel oil. PAHs were quantified as a proxy for contamination and were found to be elevated in urchins from the contaminated site (up to 231.67ng/g DW). These contaminant-experienced adult urchins produced eggs with greater levels of a broad suite of antioxidants, particularly superoxide dismutase, catalase and glyoxalase-I, than those from Cape Evans. In addition, embryos that were derived from contaminant-experienced mothers were endowed with higher baseline levels of antioxidants, which conferred an enhanced capacity to minimize oxidative damage to lipids, proteins and DNA when exposed to AN8 fuel. This pattern was strongest following exposure to 900ppm AN8, where lipid and protein damage was 5-7 times greater than baseline levels in contaminant-naïve female embryos in comparison to 3-4 times greater in contaminant-experienced female embryos. Despite this inherited resilience against oxidative stress, abnormal development was as high in these embryos when exposed to AN8 as in those derived from contaminant-naïve mothers (up to 80% abnormality), implying the conferred advantage may not translate to a fitness or survival gain, at least up to the blastulae stage. Our findings document the first evidence for parent-to-offspring transfer of oxidative stress resilience in an Antarctic marine invertebrate.
包括多环芳烃（PAHs）和金属在内的传统污染物，在一些南极海洋环境中，尤其是在科研站附近，可能会以高浓度出现。氧化应激是许多化学污染物对水生生物产生毒性的一个重要统一特征。然而，污染物对南极海洋无脊椎动物氧化生理的潜在影响尚未得到充分记录。新岛海胆（Sterechinus neumayeri）是南极洲周围浅潮下带底栖生物中的常见动物，被认为是一种重要的关键物种。本研究的目的是收集新岛海胆的氧化生物标志物基线数据，并调查野外接触化学污染物对配子健康以及氧化应激恢复力从亲代到子代传递的影响。我们分析了来自麦克默多站附近受污染物影响的地点和埃文斯角一个相对原始地点的新岛海胆的抗氧化酶活性、分子抗氧化剂谷胱甘肽水平、蛋白质羰基化、脂质过氧化以及8-羟基脱氧鸟苷（8-OHdG）水平，将其作为氧化应激生物标志物。在成年配子组织和暴露于AN8燃料油的早期胚胎中分析了生物标志物。对PAHs进行了定量分析以代表污染情况，发现受污染地点的海胆体内PAHs含量升高（高达231.67纳克/克干重）。与来自埃文斯角的海胆相比，这些接触过污染物的成年海胆所产卵子中多种抗氧化剂的水平更高，尤其是超氧化物歧化酶、过氧化氢酶和乙二醛酶-I。此外，来自接触过污染物的母体的胚胎具有更高的抗氧化剂基线水平，这使其在暴露于AN8燃料时，将脂质、蛋白质和DNA的氧化损伤降至最低的能力增强。在暴露于900ppm的AN8后，这种模式最为明显，此时脂质和蛋白质损伤比未接触过污染物的雌性胚胎的基线水平高5 - 7倍，而接触过污染物的雌性胚胎则高3 - 4倍。尽管这些胚胎具有这种遗传的抗氧化应激能力，但在暴露于AN8时，它们的异常发育情况与来自未接触过污染物的母体的胚胎一样高（高达80%的异常率），这意味着这种赋予的优势可能不会转化为适应性或生存优势，至少在囊胚阶段之前是这样。我们的研究结果首次证明了南极海洋无脊椎动物中氧化应激恢复力从亲代到子代的传递。
