College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
J Hazard Mater. 2024 Nov 5;479:135690. doi: 10.1016/j.jhazmat.2024.135690. Epub 2024 Sep 5.
β-ionone is a volatile metabolite of Microcystis aeruginosa that is toxic to aquatic organisms. Using Daphnia sinensis as model, our present study found that β-ionone could significantly reduce heart rate and feeding rate, and induce intestinal emptying. Transcriptomic analysis showed that β-ionone could significantly inhibit the expression of acetylcholinesterase (AchE) mRNA, while metabolomics further revealed that β-ionone could significantly increase the level of acetylcholine (Ach) in D. sinensis. These results indicated that β-ionone might act as an AchE inhibitor, resulting in an increase in Ach levels. To test this hypothesis, both in vivo and in vitro experiments demonstrated that β-ionone could significantly reduce AchE activity. Furthermore, the inhibitory effects of β-ionone on heart rate and feeding rate could be blocked by the M-type Ach receptor (mAchR) blocker. These findings confirm that β-ionone is a novel AchE inhibitor. β-ionone could inhibit the activity of AchE, which in turn resulted in an increase of Ach in D. sinensis. Consequently, elevated levels of Ach could suppress the heart rate and feeding rate of D. sinensis by activating the mAchR, while concurrently accelerating the rate of intestinal emptying by stimulating intestinal peristalsis, thereby obstructing the digestion of algae within the intestinal tract.
β-紫罗兰酮是铜绿微囊藻的一种挥发性代谢物，对水生生物有毒。本研究以大型溞为模型，发现β-紫罗兰酮可显著降低心率和摄食率，并诱导肠道排空。转录组分析表明，β-紫罗兰酮可显著抑制乙酰胆碱酯酶（AchE）mRNA 的表达，而代谢组学进一步表明，β-紫罗兰酮可显著增加大型溞体内的乙酰胆碱（Ach）水平。这些结果表明，β-紫罗兰酮可能作为 AchE 抑制剂，导致 Ach 水平升高。为了验证这一假设，体内和体外实验均表明，β-紫罗兰酮可显著降低 AchE 活性。此外，β-紫罗兰酮对心率和摄食率的抑制作用可被 M 型乙酰胆碱受体（mAchR）阻断剂阻断。这些发现证实了β-紫罗兰酮是一种新型的 AchE 抑制剂。β-紫罗兰酮可抑制 AchE 的活性，进而导致大型溞体内 Ach 增加。因此，升高的 Ach 水平可通过激活 mAchR 抑制大型溞的心率和摄食率，同时通过刺激肠道蠕动加速肠道排空，从而阻碍肠道内藻类的消化。
