Tartarotti B, Alfreider A, Egg M, Saul N, Schneider T, Sommaruga R, Tischler A, Vetter J
Lake and Glacier Research Group, Institute of Ecology University of Innsbruck Innsbruck Austria.
Ecophysiology, Institute of Zoology University of Innsbruck Innsbruck Austria.
Limnol Oceanogr. 2018 Jul;63(4):1579-1592. doi: 10.1002/lno.10793. Epub 2018 Feb 16.
Zooplankton from clear alpine lakes is exposed to stressful levels of solar UV radiation (UVR). As these pelagic organisms experience high UVR and large changes in solar radiation conditions between ice-free and ice-cover periods, they have evolved various strategies to minimize UVR exposure and damage. Here, we studied the relation between photoprotection levels (mycosporine-like amino acids, carotenoids), antioxidant capacities, and gene expression of heat shock proteins () as indicator of stress in the copepod during the course of a year. Expression of , , and was measured in the field (baseline expression [BE]) and after UVR exposure in the laboratory. The BE differed among genes and seasons (: high during summer, and : high during the ice-cover period). The gene expression of was upregulated after exposure to UVR (up to 5.2-fold change), while and were only constitutively expressed. A strong seasonal pattern was found in the photoprotective compounds and antioxidant capacities, with highest levels during the ice-free period. The extent of upregulation of gene expression increased with decreasing photoprotection levels and peaked 24 h post UVR exposure (9.6-fold change) at the time of lowest photoprotection (February). Our data suggest that gene expression is modulated by seasonal plasticity in photoprotection. This ability of adequate stress response is essential for survival in highly variable ecosystems such as alpine lakes.
来自清澈高山湖泊的浮游动物面临着高强度的太阳紫外线辐射（UVR）压力。由于这些浮游生物在无冰期和冰封期之间经历高紫外线辐射和太阳辐射条件的巨大变化，它们已经进化出各种策略来尽量减少紫外线辐射暴露和损害。在这里，我们研究了作为桡足类动物应激指标的光保护水平（类菌孢素氨基酸、类胡萝卜素）、抗氧化能力和热休克蛋白（）基因表达之间在一年中的关系。在野外（基线表达[BE]）和实验室紫外线辐射暴露后测量了、和的表达。BE在不同基因和季节之间存在差异（：夏季高，和：冰封期高）。暴露于紫外线辐射后，的基因表达上调（变化高达5.2倍），而和仅组成性表达。在光保护化合物和抗氧化能力方面发现了强烈的季节性模式，在无冰期水平最高。基因表达上调的程度随着光保护水平的降低而增加，并在紫外线辐射暴露后24小时（变化9.6倍）在光保护最低时（2月）达到峰值。我们的数据表明，基因表达受光保护的季节性可塑性调节。这种适当应激反应的能力对于在高山湖泊等高度可变的生态系统中生存至关重要。
