Behan-Martin M K, Jones G R, Bowler K, Cossins A R
Department of Environmental and Evolutionary Biology, University of Liverpool, UK.
Biochim Biophys Acta. 1993 Sep 19;1151(2):216-22. doi: 10.1016/0005-2736(93)90106-a.
The bilayer order of a brain synaptic membrane fraction from a number of fish, mammalian and avian species have been compared in relation to their respective body temperatures using steady-state and time-resolved fluorescence anisotropy techniques. Fluorescence anisotropy for both 1,6-diphenyl-1,3,5-hexatriene and trans-parinaric acid increased in the order: antarctic Notothenia, trout, perch, cichlid, rat and starling, this also being the order of increasing body temperature. This suggests that cold-adapted fish species possess more disordered brain membranes than warm-adapted fish species, and mammals and birds membranes were more ordered than fish membranes. Comparison of temperature profiles for both fluorescence probes showed that fish species display similar anisotropies, and by inference bilayer order, to mammals and birds when measured at their respective body temperatures. Time-resolved analysis showed that the interspecific differences in (P2) order parameter was consistently related to body temperature whilst the rotational diffusion coefficient was not. These results suggest that brain membrane order is highly conserved within the vertebrates despite large differences in thermal habits and phylogenetic position. Polar fish species have by far the lowest bilayer order indicating that invasion of extreme cold habitats involved an adaptive decrease in bilayer order and conversely adoption of a high body temperature by mammals involved an adaptive increase in bilayer order. The conservation of membrane static order for these species at their respective body temperatures indicates a regulatory control of this aspect of membrane hydrocarbon structure and the functional importance of this structure.
利用稳态和时间分辨荧光各向异性技术，比较了多种鱼类、哺乳动物和鸟类大脑突触膜组分的双层结构与其各自体温的关系。1,6-二苯基-1,3,5-己三烯和反式-降植烷酸的荧光各向异性按以下顺序增加：南极南极鱼、鳟鱼、鲈鱼、丽鱼、大鼠和椋鸟，这也是体温升高的顺序。这表明，与适应温暖环境的鱼类相比，适应寒冷环境的鱼类大脑膜的无序程度更高，而哺乳动物和鸟类的膜比鱼类的膜更有序。对两种荧光探针的温度曲线进行比较表明，当在各自体温下测量时，鱼类与哺乳动物和鸟类表现出相似的各向异性，进而推断双层结构也相似。时间分辨分析表明，（P2）序参数的种间差异与体温始终相关，而旋转扩散系数则不然。这些结果表明，尽管热习性和系统发育位置存在很大差异，但脊椎动物大脑膜的有序性高度保守。迄今为止，极地鱼类的双层结构有序性最低，这表明入侵极端寒冷的栖息地涉及双层结构有序性的适应性降低，相反，哺乳动物采用较高体温则涉及双层结构有序性的适应性增加。这些物种在各自体温下膜静态有序性的保守表明了对膜烃结构这一方面的调节控制以及该结构的功能重要性。
