Estación Experimental de Zonas Aridas, CSIC, General Segura 1, 04001 Almeria, Spain.
J Exp Biol. 2010 Feb 1;213(3):400-7. doi: 10.1242/jeb.037101.
Oxidative stress, the physiological condition whereby the production of reactive oxygen and nitrogen species overwhelms the capacity of antioxidant defences, causes damage to key bio-molecules. It has been implicated in many diseases, and is proposed as a reliable currency in the trade-off between individual health and ornamentation. Whether oxidative stress mediates the expression of carotenoid-based signals, which are among the commonest signals of many birds, fish and reptiles, remains controversial. In the present study, we explored interactions between parasites, oxidative stress and the carotenoid-based ornamentation of red grouse Lagopus lagopus scoticus. We tested whether removing nematode parasites influenced both oxidative balance (levels of oxidative damage and circulating antioxidant defences) and carotenoid-based ornamentation. At the treatment group level, parasite purging enhanced the size and colouration of ornaments but did not significantly affect circulating carotenoids, antioxidant defences or oxidative damage. However, relative changes in these traits among individuals indicated that males with a greater number of parasites prior to treatment (parasite purging) showed a greater increase in the levels of circulating carotenoids and antioxidants, and a greater decrease in oxidative damage, than those with initially fewer parasites. At the individual level, a greater increase in carotenoid pigmentation was associated with a greater reduction in oxidative damage. Therefore, an individual's ability to express a carotenoid-based ornament appeared to be linked to its current oxidative balance and susceptibility to oxidative stress. Our experimental results suggest that oxidative stress can mediate the impact of parasites on carotenoid-based signals, and we discuss possible mechanisms linking carotenoid-based ornaments to oxidative stress.
氧化应激是指活性氧和氮物种的产生超过抗氧化防御能力的生理状态，会对关键生物分子造成损伤。它与许多疾病有关，并被认为是个体健康和装饰之间权衡的可靠货币。氧化应激是否介导基于类胡萝卜素的信号的表达，而基于类胡萝卜素的信号是许多鸟类、鱼类和爬行动物最常见的信号之一，这仍然存在争议。在本研究中，我们探讨了寄生虫、氧化应激和红松鸡 Lagopus lagopus scoticus 的基于类胡萝卜素的装饰之间的相互作用。我们测试了去除线虫寄生虫是否会影响氧化平衡（氧化损伤水平和循环抗氧化防御）和基于类胡萝卜素的装饰。在处理组水平上，寄生虫清除增强了装饰物的大小和颜色，但对循环类胡萝卜素、抗氧化防御或氧化损伤没有显著影响。然而，个体之间这些特征的相对变化表明，与最初寄生虫较少的个体相比，在治疗前（寄生虫清除）具有更多寄生虫的雄性个体在循环类胡萝卜素和抗氧化剂水平上的增加更大，而在氧化损伤水平上的降低更大。在个体水平上，类胡萝卜素色素沉着的增加与氧化损伤的减少呈正相关。因此，个体表达基于类胡萝卜素的装饰物的能力似乎与其当前的氧化平衡和对氧化应激的敏感性有关。我们的实验结果表明，氧化应激可以介导寄生虫对基于类胡萝卜素的信号的影响，我们讨论了将基于类胡萝卜素的装饰物与氧化应激联系起来的可能机制。
