Franklin & Marshall College, Biology Department, Lancaster, PA 17604-3003, USA.
J Exp Biol. 2012 Apr 1;215(Pt 7):1106-16. doi: 10.1242/jeb.062273.
The ability to acclimate to variable environmental conditions affects the biogeographic range of species, their success at colonizing new habitats, and their likelihood of surviving rapid anthropogenic climate change. Here we compared responses to temperature acclimation (4 weeks at 7, 13 and 19°C) in gill tissue of the warm-adapted intertidal blue mussel Mytilus galloprovincialis, an invasive species in the northeastern Pacific, and the cold-adapted M. trossulus, the native congener in the region, to better understand the physiological differences underlying the ongoing competition. Using two-dimensional gel electrophoresis and tandem mass spectrometry, we showed that warm acclimation caused changes in cytoskeletal composition and proteins of energy metabolism in both species, consistent with increasing rates of filtration and respiration due to increased ciliary activity. During cold acclimation, changes in cytoskeletal proteins were accompanied by increasing abundances of oxidative stress proteins and molecular chaperones, possibly because of the increased production of aldehydes as indicated by the upregulation of aldehyde dehydrogenase. The cold-adapted M. trossulus showed increased abundances of molecular chaperones at 19°C, but M. galloprovincialis did not, suggesting that the two species differ in their long-term upper thermal limits. In contrast, the warm-adapted M. galloprovincialis showed a stronger response to cold acclimation than M. trossulus, including changes in abundance in more proteins and differing protein expression profiles between 7 and 13°C, a pattern absent in M. trossulus. In general, increasing levels of oxidative stress proteins inversely correlate with modifications in Krebs cycle and electron transport chain proteins, indicating a trade-off between oxidative stress resistance and energy production. Overall, our results help explain why M. galloprovincialis has replaced M. trossulus in southern California over the last century, but also suggest that M. trossulus may maintain a competitive advantage at colder temperatures. Anthropogenic global warming may reinforce the advantage M. galloprovincialis has over M. trossulus in the warmer parts of the latter's historical range.
适应可变环境条件的能力影响物种的生物地理范围、它们在新栖息地的殖民成功以及它们在快速人为气候变化中幸存的可能性。在这里，我们比较了适应温度（7、13 和 19°C 下 4 周）对暖水适应的潮间带蓝贻贝 Mytilus galloprovincialis （太平洋东北部的入侵物种）和冷水适应的 M. trossulus （该地区的本地同属种）的贻贝组织的反应，以更好地理解导致正在进行的竞争的生理差异。使用二维凝胶电泳和串联质谱法，我们表明，暖水适应导致两种物种的细胞骨架组成和能量代谢蛋白发生变化，这与由于纤毛活动增加导致的过滤和呼吸率增加一致。在冷适应期间，细胞骨架蛋白的变化伴随着氧化应激蛋白和分子伴侣的丰度增加，这可能是由于醛脱氢酶的上调导致醛的产量增加。冷水适应的 M. trossulus 在 19°C 时显示出分子伴侣的丰度增加，但 M. galloprovincialis 没有，这表明这两个物种在其长期的上限温度方面存在差异。相比之下，暖水适应的 M. galloprovincialis 对冷适应的反应强于 M. trossulus，包括在更多蛋白质中的丰度变化和在 7°C 和 13°C 之间不同的蛋白质表达谱，而 M. trossulus 则没有这种模式。一般来说，氧化应激蛋白水平的增加与三羧酸循环和电子传递链蛋白的修饰呈负相关，这表明氧化应激抗性和能量产生之间存在权衡。总的来说，我们的研究结果有助于解释为什么 M. galloprovincialis 在过去一个世纪中取代了 M. trossulus 在南加州的地位，但也表明 M. trossulus 可能在较冷的温度下保持竞争优势。人为全球变暖可能会加强 M. galloprovincialis 在后者历史分布的较暖地区相对于 M. trossulus 的优势。
