Aquatic Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, Environment and Climate Change Canada, St. Lawrence Centre, 105 McGill Street, 7th floor, Montreal, Quebec H2Y 2E7, Canada.
St. Andrews Biological Station, Fisheries and Oceans Canada, 125 Marine Science Drive, St. Andrews, New Brunswick E5B 0E4, Canada.
Parasitology. 2021 Jun;148(7):827-834. doi: 10.1017/S003118202100038X. Epub 2021 Mar 9.
Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematode Oswaldocruzia sp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance of Oswaldocruzia sp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances of Oswaldocruzia sp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.
自然和人为压力源，包括寄生虫和农药，可能会导致动物氧化应激。测量对环境干扰特别敏感的哨兵物种的氧化应激反应，不仅可以深入了解宿主生理学，还可以作为生态系统健康的有用指标。新变态的北方豹蛙（Lithobates pipiens）是一种对环境变化非常敏感的指示物种，从暴露于不同浓度除草剂莠去津的农业和非农业湿地中采集。确定了某些寄生虫丰度及其与莠去津暴露的相互作用对青蛙氧化应激的显著影响。具体来说，感染棘口吸虫囊蚴的青蛙中检测到蛋白质水平升高。此外，Oswaldocruzia sp. 线虫与硫醇浓度和过氧化氢酶活性的增加显著相关。在莠去津暴露和 Oswaldocruzia sp. 的丰度与硫醇之间观察到显著的寄生虫×莠去津相互作用，因为在低莠去津地区，随着寄生虫丰度的增加，硫醇浓度增加，而在高莠去津湿地中则减少。此外，还观察到 Oswaldocruzia sp. 和 gorgoderid 吸虫丰度对硫醇浓度的显著相互作用。这些发现表明，在自然生态系统中对动物进行氧化应激研究应考虑到寄生虫的混杂影响，特别是在农业景观中的两栖动物。
