Berger Michael S, Emlet Richard B
Oregon Institute of Marine Biology, University of Oregon, Charleston, Oregon 97420, USA.
Biol Bull. 2007 Jun;212(3):232-41. doi: 10.2307/25066605.
In the intertidal zone in the Pacific Northwest, body temperatures of sessile marine organisms can reach 35 degrees C for an extended time during low tide, resulting in potential physiological stress. We used immunochemical assays to examine the effects of thermal stress on endogenous Hsp70 levels in the intertidal barnacle Balanus glandula. After thermal stress, endogenous Hsp70 levels did not increase above control levels in B. glandula exposed to 20 and 28 degrees C. In a separate experiment, endogenous Hsp70 levels were higher than control levels when B. glandula was exposed to 34 degrees C for 8.5 h. Although an induced heat-shock response was observed, levels of conjugated ubiquitin failed to indicate irreversible protein damage at temperatures up to 34 degrees C. With metabolic labeling, we examined temperature acclimation and thermally induced heat-shock proteins in B. glandula. An induced heat-shock response of proteins in the 70-kDa region (Hsp70) occurred in B. glandula above 23 degrees C. This heat-shock response was similar in molting and non-molting barnacles. Acclimation of B. glandula to relatively higher temperatures resulted in higher levels of protein synthesis in the 70-kDa region and lack of an upward shift in the induction temperature for heat-shock proteins. Our results suggest that B. glandula may be well adapted to life in the high intertidal zone but may lack the plasticity to acclimate to higher temperatures.
在太平洋西北部的潮间带，固着海洋生物的体温在退潮期间可长时间达到35摄氏度，从而导致潜在的生理压力。我们使用免疫化学分析方法来检测热应激对潮间带藤壶Balanus glandula体内Hsp70水平的影响。热应激后，暴露于20摄氏度和28摄氏度的B. glandula体内的内源性Hsp70水平并未升高至对照水平之上。在另一项实验中，当B. glandula暴露于34摄氏度8.5小时后，其体内的内源性Hsp70水平高于对照水平。尽管观察到了诱导热休克反应，但在高达34摄氏度的温度下，结合泛素水平并未显示出不可逆的蛋白质损伤。通过代谢标记，我们检测了B. glandula的温度适应和热诱导热休克蛋白。高于23摄氏度时，B. glandula中出现了70 kDa区域（Hsp70）蛋白质的诱导热休克反应。这种热休克反应在蜕皮和未蜕皮的藤壶中相似。B. glandula对相对较高温度的适应导致70 kDa区域的蛋白质合成水平升高，且热休克蛋白的诱导温度没有向上偏移。我们的结果表明，B. glandula可能很好地适应了高潮间带的生活，但可能缺乏适应更高温度的可塑性。
