Overgaard Johannes, Tomcala Ales, Sørensen Jesper G, Holmstrup Martin, Krogh Paul Henning, Simek Petr, Kostál Vladimir
Department of Terrestrial Ecology, National Environmental Research Institute, University of Aarhus, Vejlsøvej 25, P.O. Box 314, DK-8600 Silkeborg, Denmark.
J Insect Physiol. 2008 Mar;54(3):619-29. doi: 10.1016/j.jinsphys.2007.12.011. Epub 2008 Jan 4.
Adaptative responses of ectothermic organisms to thermal variation typically involve the reorganization of membrane glycerophospholipids (GPLs) to maintain membrane function. We investigated how acclimation at 15, 20 and 25 degrees C during preimaginal development influences the thermal tolerance and the composition of membrane GPLs in adult Drosophila melanogaster. Long-term cold survival was significantly improved by low acclimation temperature. After 60 h at 0 degrees C, more than 80% of the 15 degrees C-acclimated flies survived while none of the 25 degrees C-acclimated flies survived. Cold shock tolerance (1h at subzero temperatures) was also slightly better in the cold acclimated flies. LT50 shifted down by ca 1.5 degrees C in 15 degrees C-acclimated flies in comparison to those acclimated at 25 degrees C. In contrast, heat tolerance was not influenced by acclimation temperature. Low temperature acclimation was associated with the increase in proportion of ethanolamine (from 52.7% to 58.5% in 25 degrees C-acclimated versus 15 degrees C-acclimated flies, respectively) at the expense of choline in GPLs. Relatively small, but statistically significant changes in lipid molecular composition were observed with decreasing acclimation temperature. In particular, the proportions of glycerophosphoethanolamines with linoleic acid (18:2) at the sn-2 position increased. No overall change in the degree of fatty acid unsaturation was observed. Thus, cold tolerance but not heat tolerance was influenced by preimaginal acclimation temperature and correlated with the changes in GPL composition in membranes of adult D. melanogaster.
变温生物对温度变化的适应性反应通常涉及膜甘油磷脂（GPLs）的重新组织以维持膜功能。我们研究了在成虫前期发育过程中，15、20和25摄氏度的驯化如何影响成年黑腹果蝇的热耐受性和膜GPLs的组成。低驯化温度显著提高了长期耐寒性。在0摄氏度下放置60小时后，15摄氏度驯化的果蝇中有超过80%存活，而25摄氏度驯化的果蝇无一存活。冷驯化果蝇的冷休克耐受性（在零下温度下1小时）也略好一些。与25摄氏度驯化的果蝇相比，15摄氏度驯化的果蝇的致死中时（LT50）下降了约1.5摄氏度。相反，耐热性不受驯化温度的影响。低温驯化与乙醇胺比例的增加有关（25摄氏度驯化的果蝇与15摄氏度驯化的果蝇相比，分别从52.7%增加到58.5%），同时GPLs中的胆碱比例相应减少。随着驯化温度的降低，观察到脂质分子组成有相对较小但具有统计学意义的变化。特别是，在sn-2位置含有亚油酸（18:2）的甘油磷酸乙醇胺的比例增加。未观察到脂肪酸不饱和度的总体变化。因此，成虫前期驯化温度影响了耐寒性而非耐热性，并且与成年黑腹果蝇膜中GPL组成的变化相关。
