College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
J Hazard Mater. 2024 Mar 5;465:133248. doi: 10.1016/j.jhazmat.2023.133248. Epub 2023 Dec 14.
β-cyclocitral is one of the major compounds in cyanobacterial volatile organic compound (VOCs) and can poison other aquatic organisms. To investigate the effect of β-cyclocitral on cyanobacterial-grazer interactions, Daphnia sinensis was fed Microcystis aeruginosa and exposed to β-cyclocitral. Our present study demonstrated that M. aeruginosa could significantly inhibit D. sinensis grazing. And the grazing inhibition by Microcystis aeruginosa results from the suppression of feeding rate, heart rate, thoracic limb activity and swimming speed of D. sinensis. In addition, M. aeruginosa could also induce intestinal peristalsis and emptying in D. sinensis. Interestingly, our present study found that the exposure to β-cyclocitral could mimic a range of phenotypes induced by M. aeruginosa in D. sinensis. These results suggested that M. aeruginosa could release β-cyclocitral to inhibit Daphnia grazing. To further examine the toxic mechanism of β-cyclocitral in Daphnia, several in vivo and in vitro experiments displayed that β-cyclocitral was a novel inhibitor of acetylcholinesterase (AChE). It could induce the accumulation of acetylcholine (ACh) by inhibiting AchE activity in D. sinensis. High level of endogenous Ach could inhibit feeding rate and induce intestinal peristalsis and emptying in D. sinensis.
β-环柠檬醛是蓝藻挥发性有机化合物（VOCs）中的主要化合物之一，可毒害其他水生生物。为了研究β-环柠檬醛对蓝藻-食草动物相互作用的影响，用铜绿微囊藻喂食溞，并暴露于β-环柠檬醛。本研究表明，铜绿微囊藻可显著抑制溞的摄食。并且，铜绿微囊藻对溞的摄食抑制作用来自于对溞的摄食率、心率、胸肢活动和游泳速度的抑制。此外，铜绿微囊藻还可以诱导溞的肠道蠕动和排空。有趣的是，本研究发现，暴露于β-环柠檬醛可以模拟铜绿微囊藻在溞体内诱导的一系列表型。这些结果表明，铜绿微囊藻可能会释放β-环柠檬醛来抑制溞的摄食。为了进一步研究β-环柠檬醛对溞的毒性机制，进行了一系列体内和体外实验，结果显示β-环柠檬醛是一种新型乙酰胆碱酯酶（AChE）抑制剂。它可以通过抑制 D. sinensis 中的 AChE 活性来诱导乙酰胆碱（ACh）的积累。高水平的内源性 ACh 可以抑制溞的摄食率，并诱导肠道蠕动和排空。
