Abstract：
Guvermectin, as a novel nucleoside-like biopesticide, could increase the rice yield excellently, but the potential environmental behaviors remain unclear, which pose potential health risks. Therefore, the uptake and biotransformation of guvermectin in three types of crops (rice, lettuce, and carrot) were first evaluated with a hydroponic system. Guvermectin could be rapidly absorbed and reached equilibrium in roots (12-36 h) and shoots (24-60 h) in three plants, and guvermectin was also vulnerable to dissipation in roots (t1/2 1.02-3.65 h) and shoots (t1/2 9.30-17.91 h). In addition, 8 phase I and 2 phase II metabolites, transformed from guvermectin degradation in vivo and in vitro exposure, were identified, and one was confirmed as psicofuranine, which had antibacterial and antitumor properties; other metabolites were nucleoside-like chemicals. Molecular simulation and quantitative polymerase chain reaction further demonstrated that guvermectin was metabolized by the catabolism pathway of an endogenous nucleotide. Guvermectin had similar metabolites in three plants, but the biotransformation ability had a strong species dependence. In addition, all the metabolites exhibit neglectable toxicities (bioconcentration factor <2000 L/kg b.w., LC50,rat > 5000 mg/kg b.w.) by prediction. The study provided valuable evidence for the application of guvermectin and a better understanding of the biological behavior of nucleoside-like pesticides.
摘要：
古维菌素,作为一种新型的核苷类生物农药，可以很好地提高水稻产量，但是潜在的环境行为仍然不清楚，这构成了潜在的健康风险。因此,三种作物(水稻，生菜,和胡萝卜）首先使用水培系统进行评估。在3种植物的根(12-36h)和芽(24-60h)中都能迅速吸收并达到平衡,并且古维菌素也容易在根（t1/21.02-3.65h）和芽（t1/29.30-17.91h）中消散。此外,8个I相和2个II相代谢物，从体内和体外暴露的格维菌素降解转化，被确认,其中一个被证实为阿糖胞苷，具有抗菌和抗肿瘤特性；其他代谢物是核苷样化学物质。分子模拟和定量聚合酶链反应进一步证明，古维菌素是通过内源性核苷酸的分解代谢途径代谢的。古维菌素在三种植物中具有相似的代谢产物，但是生物转化能力具有很强的物种依赖性。此外,所有代谢物均表现出可忽略的毒性（生物富集系数<2000L/kgb.w.，LC50，大鼠>5000mg/kgb.w.)通过预测。该研究为古维菌素的应用和更好地理解核苷类农药的生物学行为提供了有价值的证据。
