Abstract：
n-3 Long-chain polyunsaturated fatty acids (n-3 LC-PUFAs), including eicosapentaenoic acid (EPA), are essential multifunctional nutrients in animals. Microorganisms such as microalgae are known to be n-3 LC-PUFA producers in aquatic environments. Various aquatic invertebrates, including Harpacticoida copepods, and a few terrestrial invertebrates, such as the nematode Caenorhabditis elegans, possess n-3 LC-PUFA biosynthetic enzymes. However, the capacity for n-3 LC-PUFA biosynthesis and the underlying molecular mechanisms in terrestrial insects are largely unclear. In this study, we investigated the fatty acid biosynthetic pathway in the silkworm Bombyx mori and found that EPA was present in silkworms throughout their development. Stable isotope tracing revealed that dietary α-linolenic acid (ALA) was metabolized to EPA in silkworm larvae. These results indicated that silkworms synthesize EPA from ALA. Given that EPA is enriched in the central nervous system, we propose that EPA confers optimal neuronal functions, similar to docosahexaenoic acid, in the mammalian nervous system.
摘要：
n-3长链多不饱和脂肪酸（n-3LC-PUFA），包括二十碳五烯酸（EPA），是动物体内必需的多功能营养素。已知微生物例如微藻是水生环境中的n-3LC-PUFA生产者。各种水生无脊椎动物，包括Harpacticoidaco足类动物，和一些陆地无脊椎动物，比如线虫秀丽隐杆线虫，具有n-3LC-PUFA生物合成酶。然而,其在陆生昆虫中n-3LC-PUFA生物合成的能力和潜在的分子机制尚不清楚。在这项研究中,我们研究了家蚕脂肪酸的生物合成途径，发现EPA在家蚕的整个发育过程中都存在。稳定同位素示踪表明，家蚕幼虫中的膳食α-亚麻酸（ALA）被代谢为EPA。这些结果表明家蚕从ALA合成EPA。鉴于EPA在中枢神经系统中富集，我们建议EPA赋予最佳的神经元功能，类似于二十二碳六烯酸，哺乳动物的神经系统。
