本期Scientific Reports上发表的一篇文章提出，不同种类的鲸利用不同机制来抵抗紫外线(UV)辐射的有害影响。还需要进一步的研究来弄清UV辐射对鲸的长期影响。
以前的研究表明，紫外线能对鲸造成皮肤损伤。Mark Birch-Machin、Karina Acevedo-Whitehouse及其同事在基因层面上研究了UV辐射对鲸的影响，并将损伤与鲸的迁徙模式联系了起来。该小组测定了来自蓝鲸、长须鲸和抹香鲸的皮肤样品中的线粒体DNA(mtDNA)水平，将其作为DNA损伤的一个标记。
作者发现，较高的黑色素水平倾向于与较低的微损伤和mtDNA损伤水平相关联，这说明黑色素可能对太阳辐射有保护作用。他们发现，蓝鲸可以响应于紫外线而改变它们皮肤的色素沉积。这种响应于UV辐射而改变黑色素水平（来使皮肤变成象征健康的棕色）的能力可能与蓝鲸的迁徙模式有关，因为它们每年要从较高纬度地区迁徙到较低纬度地区，进入到紫外线水平较高的环境中。长须鲸永久性地在一个紫外线水平高的区域生活，它们改变皮肤色素沉积的能力降低，其皮肤中的黑色素水平始终保持较高。在所研究过的鲸类中，对长须鲸所记录到的晒伤发生数量最低。
抹香鲸（它们在海洋表面上一次可以呆长达六小时）的反应方式不同，它们会响应于紫外线辐射激活基因毒性应激通道。较高水平的HSP70（作为这一反应一部分而表达的蛋白之一）被发现与抹香鲸较低的mtDNA损伤发生率相关联，说明这些通道也许能防护紫外线损伤。（生物谷 Bioon.com）
生物谷推荐的英文摘要
Scientific Reports doi:10.1038/srep02386
Whales Use Distinct Strategies to Counteract Solar Ultraviolet Radiation
Laura M. Martinez-Levasseur,1, 2, 7 Mark A. Birch-Machin,3 Amy Bowman,3 Diane Gendron,4 Elizabeth Weatherhead,5 Robert J. Knell2 & Karina Acevedo-Whitehouse1, 6
A current threat to the marine ecosystem is the high level of solar ultraviolet radiation (UV). Large whales have recently been shown to suffer sun-induced skin damage from continuous UV exposure. Genotoxic consequences of such exposure remain unknown for these long-lived marine species, as does their capacity to counteract UV-induced insults. We show that UV exposure induces mitochondrial DNA damage in the skin of seasonally sympatric fin, sperm, and blue whales and that this damage accumulates with age. However, counteractive molecular mechanisms are markedly different between species. For example, sperm whales, a species that remains for long periods at the sea surface, activate genotoxic stress pathways in response to UV exposure whereas the paler blue whale relies on increased pigmentation as the season progresses. Our study also shows that whales can modulate their responses to fluctuating levels of UV, and that different evolutionary constraints may have shaped their response strategies.
