Faassen Elisabeth J, García-Altares María, Mendes e Mello Mariana, Lürling Miquel
Wageningen University, P.O. Box 47, Wageningen, 6700 DD, The Netherlands.
Wageningen University, P.O. Box 47, Wageningen, 6700 DD, The Netherlands; Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil.
Aquat Toxicol. 2015 Nov;168:98-107. doi: 10.1016/j.aquatox.2015.09.018. Epub 2015 Oct 9.
β-N-Methylamino-l-alanine (BMAA) is a neurotoxin that is suspected to play a role in the neurological diseases amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease. BMAA has been detected in phytoplankton and globally, the main exposure routes for humans to BMAA are through direct contact with phytoplankton-infested waters and consumption of BMAA-contaminated fish and invertebrates. As BMAA can be transferred from mothers to offspring in mammals, BMAA exposure is expected to have transgenerational effects. The aim of our study was to determine whether maternal exposure to BMAA affects offspring fitness in zooplankton. We performed a multigenerational life history experiment and a multigenerational uptake experiment with the water flea Daphnia magna as a model species. In both experiments, offspring from nonexposed and exposed mothers were raised in clean and BMAA-containing medium. Direct exposure to 110μg/l BMAA reduced survival, somatic growth, reproduction and population growth. Maternal exposure did not affect D. magna fitness: animals from exposed mothers that were raised in clean medium had a higher mortality and produced lighter neonates than the controls, but this did not result in lower population growth rates. No evidence of adaptation was found. Instead, multigeneration exposure to BMAA had a negative effect: animals that were exposed during two generations had a lower brood viability and neonate weight than animals born from unexposed mothers, but raised in BMAA-containing medium. Maternal transfer of BMAA was observed, but BMAA concentrations in neonates raised in BMAA containing medium were similar for animals born from exposed and unexposed mothers. Our results indicate that zooplankton might be an important vector for the transfer of BMAA along the pelagic food chain, but whether BMAA plays a role in preventing zooplankton from controlling cyanobacterial blooms needs further investigation.
β-N-甲基氨基-L-丙氨酸（BMAA）是一种神经毒素，被怀疑在肌萎缩侧索硬化症、阿尔茨海默病和帕金森病等神经疾病中起作用。已在浮游植物中检测到BMAA，在全球范围内，人类接触BMAA的主要途径是直接接触受浮游植物污染的水域以及食用受BMAA污染的鱼类和无脊椎动物。由于BMAA可在哺乳动物中从母体转移至后代，预计BMAA暴露会产生跨代效应。我们研究的目的是确定母体暴露于BMAA是否会影响浮游动物后代的适应性。我们以大型溞作为模式物种进行了多代生活史实验和多代摄取实验。在这两个实验中，未暴露和暴露母体的后代分别在清洁培养基和含BMAA的培养基中饲养。直接暴露于110μg/l的BMAA会降低存活率、体细胞生长、繁殖和种群增长。母体暴露并未影响大型溞的适应性：在清洁培养基中饲养的暴露母体的动物比对照组有更高的死亡率，且产出的幼体更轻，但这并未导致种群增长率降低。未发现适应的证据。相反，多代暴露于BMAA有负面影响：两代暴露的动物比未暴露母体所生但在含BMAA培养基中饲养的动物有更低的育雏活力和幼体重量。观察到了BMAA的母体转移，但在含BMAA培养基中饲养的幼体中，暴露和未暴露母体所生动物的BMAA浓度相似。我们的结果表明，浮游动物可能是BMAA沿远洋食物链转移的重要载体，但BMAA是否在阻止浮游动物控制蓝藻水华方面起作用还需要进一步研究。
