Malcicka Miriama, Ruther Joachim, Ellers Jacintha
Department of Ecological Sciences, Section Animal Ecology, Vrije Universiteit, Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.
Institute of Zoology, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
J Chem Ecol. 2017 Sep;43(9):911-919. doi: 10.1007/s10886-017-0878-0. Epub 2017 Aug 19.
Many ecological interactions in communities take place between consumers and the organisms they feed on. Continuous surplus of specific nutritional compounds in the diet may lead to evolutionary changes in the metabolic capacity of the consumer, leaving the biosynthesis of such compounds prone to genetic decay and render organisms auxotrophic. A nutrient that is essential to many organisms is the unsaturated fatty acid, linoleic acid (LA; 18:2n-6), which is important in the maintenance of cell membrane fluidity and as a precursor for signaling molecules. LA is readily synthesized in bacteria, protozoa and plants, but it was long thought that all animals lack this ability. Although the majority of animals lack the ability for LA biosynthesis, an increasing number of studies have shown that LA is commonly synthesized in arthropods. Here, we investigated a basal hexapod group, Collembola, to shed light on early evolution of LA synthetic ability in arthropods and its relation to dietary composition. We use stable isotope labeling to detect biosynthesis of LA in Collembola fed with C-OA oleic acid (OA; 18:1n-9), a precursor of LA. Our data demonstrate that LA biosynthesis is common among Collembola with 10 out of 16 tested species being able to synthesize LA and 4 species lacking this ability. However, we did not find clear evidence for a relationship between LA synthetic ability and the natural diet of species. Thus, the selective pressures underlying LA biosynthesis might be species-specific and further research will shed new light on understanding this evolutionary process.
群落中的许多生态相互作用发生在消费者与其所捕食的生物之间。饮食中特定营养化合物的持续过剩可能导致消费者代谢能力的进化变化，使此类化合物的生物合成容易发生基因衰退，并使生物产生营养缺陷型。对许多生物至关重要的一种营养素是不饱和脂肪酸亚油酸（LA；18:2n-6），它在维持细胞膜流动性以及作为信号分子的前体方面很重要。亚油酸在细菌、原生动物和植物中很容易合成，但长期以来人们一直认为所有动物都缺乏这种能力。尽管大多数动物缺乏合成亚油酸的能力，但越来越多的研究表明，亚油酸在节肢动物中普遍合成。在这里，我们研究了一个基础六足动物类群弹尾目，以阐明节肢动物中亚油酸合成能力的早期进化及其与饮食组成的关系。我们使用稳定同位素标记来检测以亚油酸前体C-油酸（OA；18:1n-9）喂养的弹尾目中亚油酸的生物合成。我们的数据表明，亚油酸生物合成在弹尾目中很常见，16个受试物种中有10个能够合成亚油酸，4个物种缺乏这种能力。然而，我们没有找到明确的证据表明亚油酸合成能力与物种的自然饮食之间存在关系。因此，亚油酸生物合成背后的选择压力可能是物种特异性的，进一步的研究将为理解这一进化过程带来新的启示。
