Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
Aquat Toxicol. 2022 Aug;249:106210. doi: 10.1016/j.aquatox.2022.106210. Epub 2022 May 27.
The neurotoxic secondary metabolite β-N-methylamino-L-alanine (BMAA) and its structural isomer 2,4-diaminobutyric acid (DAB) are known to be produced by various phytoplankton groups. Despite the worldwide spread of these toxin producers, no obvious role and function of BMAA and DAB in diatoms have been identified. Here, we investigated the effects of biotic factors, i.e., predators and competitors, as possible causes of BMAA and/or DAB regulation in the two diatom species Phaeodactylum tricornutum and Thalassiosira pseudonana. DAB was specifically regulated in T. pseudonana by the presence of predators and competitors. The effects of DAB on both diatoms as competitors and on the copepod Tigriopus sp. as predator at individual and at population levels were examined. The toxic effects of DAB on the growth of T. pseudonana and the population of Tigriopus sp. were significant. The effect of DAB as a defensive secondary metabolite is assumed to be environmentally relevant depending on the number of the copepods. The results show a potential function of DAB that can play an important role in defense mechanisms of T. pseudonana.
神经毒性次生代谢物β-N-甲基氨基-L-丙氨酸（BMAA）及其结构异构体 2,4-二氨基丁酸（DAB）已知由各种浮游植物群产生。尽管这些毒素生产者在全球范围内广泛存在，但尚未确定 DAB 和 BMAA 在硅藻中的明显作用和功能。在这里，我们研究了生物因素，即捕食者和竞争者，作为调节两种硅藻物种三角褐指藻和拟菱形藻中 BMAA 和/或 DAB 的可能原因。在存在捕食者和竞争者的情况下，DAB 特异性地在拟菱形藻中被调节。我们在个体和种群水平上研究了 DAB 作为竞争者对硅藻的影响，以及 DAB 对桡足类动物 Tigriopus sp. 作为捕食者的影响。DAB 对拟菱形藻生长和桡足类动物 Tigriopus sp. 种群的毒性作用是显著的。根据桡足类动物的数量，DAB 作为防御性次生代谢物的作用假定与环境有关。研究结果表明 DAB 具有潜在的功能，可能在拟菱形藻的防御机制中发挥重要作用。
