College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China; Environmental Information Institute, Dalian Maritime University, Dalian 116026, China.
Ecotoxicol Environ Saf. 2021 Mar 1;210:111852. doi: 10.1016/j.ecoenv.2020.111852. Epub 2021 Jan 5.
Symbiosis of marine algae is inevitable in the marine environment, and species may occur interaction on the growth. In this study, the macroalgae Ulva pertusa and marine microalgae Heterosigma akashiwo were selected as target species to study the interaction mechanism between them. After the 8 days of co-cultivation, the inhibition on growth was observed for both of U. pertusa and H. akashiwo. Eight fatty acids in U. pertusa was detected, with the significant decrease in contents of polyunsaturated fatty acids (PUFAs) especially for C18:2, C18:3n-3 and C18:3n-6. Twelve fatty acids in H. akashiwo was detected, with the significant change for PUFAs. PUFA concentrations in the co-culture group were less than those in the mono-culture. Meanwhile the principal component analysis was conducted to insight into the interaction between U. pertusa and H. akashiwo by fatty acids content and carbon stable isotope ratio of fatty acids (δC). Fatty acid content could not distinguish mono and co-culture. However, δC could distinguish not only the culture time of algae, but also the living environment of algae. In addition, this study combined fatty acids content and δC to explore the release of fatty acids by algae into the seawater. The C18:3n-3 was identified as the allelochemical released by U. pertusa to inhibit the growth of H. akashiwo. The ratio of δC in seawater decreased. This study provides a theoretical basis for the symbiosis of marine algae, and a new method of compound-specific stable carbon isotopes was used to better explore the metabolism of fatty acids in algae.
海洋藻类的共生在海洋环境中是不可避免的，物种之间可能会发生相互作用。在本研究中，选择大型海藻孔石莼（Ulva pertusa）和海洋微藻赤潮异弯藻（Heterosigma akashiwo）作为目标物种，研究它们之间的相互作用机制。经过 8 天的共培养，孔石莼和赤潮异弯藻的生长均受到抑制。检测到孔石莼中的 8 种脂肪酸，其中多不饱和脂肪酸（PUFAs），特别是 C18:2、C18:3n-3 和 C18:3n-6 的含量显著下降。检测到赤潮异弯藻中的 12 种脂肪酸，其中 PUFAs 发生了显著变化。共培养组的 PUFA 浓度低于单培养组。同时，通过脂肪酸含量和脂肪酸碳稳定同位素比值（δC）进行主成分分析，深入了解孔石莼和赤潮异弯藻之间的相互作用。脂肪酸含量无法区分单培养和共培养。然而，δC 不仅可以区分藻类的培养时间，还可以区分藻类的生活环境。此外，本研究结合脂肪酸含量和δC 来探索藻类向海水中释放脂肪酸的情况。鉴定出 C18:3n-3 是孔石莼释放的化感物质，抑制赤潮异弯藻的生长。海水的δC 比值降低。本研究为海洋藻类的共生提供了理论依据，并采用新的化合物特异性稳定碳同位素方法，更好地探索了藻类脂肪酸的代谢。
