Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2020 Aug;246:110719. doi: 10.1016/j.cbpa.2020.110719. Epub 2020 May 4.
Understanding physiological tolerances of marine organisms to environmental stress is key to predicting species susceptability under climate change. Along the Pacific Coast of the U.S.A. intertidal mussel congeners (genus Mytilis) vary in their physiological stress tolerances, with the invasive M. galloprovincialis being heat tolerant but vulnerable to hyposalinity while the native M. trossulus is vulnerable to heat stress and tolerant of hyposalinity. Sirtuins, a family of NAD-dependent deacylases, may influence the environmental stressor tolerances in these mussel congeners. The purpose of our study was to determine the mechanism by which sirtuins may confer differential stress responses in the two mussel congeners. Mussels (N = 6 per species) were acclimated to laboratory conditions in tidal simulators and exposed to sirtuin inhibitors (suramin and nicotinamide). Following inhibition, mussels were exposed to hyposalinity stress (29 ppt) for 6 h followed by aerial heat stress (32 °C) for 6 h after which mussel gill was dissected for proteomic analysis. During sirtuin inhibition we found a reduction of cellular stress response (CSR) proteins (molecular chaperones, antioxidants), which are key to maintaining cellular homeostasis. Moreover, we found differential stress responses between the two species under aerial heat combined with hyposalinity exposure. Three-way interactions (aerial heat, hyposalinity and sirtuin inhibition combined) showed complex interactive effects with sirtuins as potential modulators. Thus, our study suggests that sirtuins are contributing to the species-specific CSR in Mytilus and our multiple-stressor approach provides information used to make predictions regarding climate change effects on these competing species.
了解海洋生物对环境压力的生理耐受性是预测物种在气候变化下易感性的关键。在美国太平洋沿岸，潮间带贻贝属（贻贝属）在生理应激耐受力方面存在差异，入侵物种 M. galloprovincialis 耐热但对低盐度敏感，而本地物种 M. trossulus 则对热应激敏感但能耐受低盐度。Sirtuins 是一种 NAD 依赖性去乙酰化酶家族，可能影响这些贻贝属的环境应激耐受能力。我们的研究目的是确定 Sirtuins 如何在两种贻贝属中赋予不同的应激反应机制。贻贝（每种物种 N = 6）在潮汐模拟器中适应实验室条件，并暴露于 Sirtuins 抑制剂（苏拉明和烟酰胺）下。抑制后，贻贝暴露于低盐度应激（29 ppt）6 小时，然后暴露于空气热应激（32°C）6 小时，然后解剖贻贝鳃进行蛋白质组学分析。在 Sirtuins 抑制期间，我们发现细胞应激反应（CSR）蛋白（分子伴侣、抗氧化剂）减少，这是维持细胞内稳态的关键。此外，我们发现两种物种在空气热与低盐度暴露下存在不同的应激反应。三向相互作用（空气热、低盐度和 Sirtuins 抑制的组合）显示出与 Sirtuins 作为潜在调节剂的复杂相互作用效应。因此，我们的研究表明 Sirtuins 对 Mytilus 的物种特异性 CSR 有贡献，我们的多胁迫方法提供了有关这些竞争物种对气候变化影响的预测信息。
