University of Central Florida College of Medicine, Department of Internal Medicine, Orlando, Florida, United States of America.
University of Central Florida College of Engineering, Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, Orlando, Florida, United States of America.
PLoS Negl Trop Dis. 2020 Sep 25;14(9):e0008654. doi: 10.1371/journal.pntd.0008654. eCollection 2020 Sep.
Effectively controlling vector mosquito populations while avoiding the development of resistance remains a prevalent and increasing obstacle to integrated vector management. Although, metallic nanoparticles have previously shown promise in controlling larval populations via mechanisms which are less likely to spur resistance, the impacts of such particles on life history traits and fecundity of mosquitoes are understudied. Herein, we investigate the chemically well-defined cerium oxide nanoparticles (CNPs) and silver-doped nanoceria (AgCNPs) for larvicidal potential and effects on life history traits and fecundity of Aedes (Ae.) aegypti mosquitoes. When 3rd instar larvae were exposed to nanoceria in absence of larval food, the mortality count disclosed significant activity of AgCNPs over CNPs (57.8±3.68% and 17.2±2.81% lethality, respectively) and a comparable activity to Ag+ controls (62.8±3.60% lethality). The surviving larvae showed altered life history traits (e.g., reduced egg hatch proportion and varied sex ratios), indicating activities of these nanoceria beyond just that of a larvicide. In a separate set of experiments, impacts on oocyte growth and egg generation resulting from nanoceria-laced blood meals were studied using confocal fluorescence microscopy revealing oocytes growth-arrest at 16-24h after feeding with AgCNP-blood meals in some mosquitoes, thereby significantly reducing average egg clutch. AgCNPs caused ~60% mortality in 3rd instar larvae when larval food was absent, while CNPs yielded only ~20% mortality which contrasts with a previous report on green-synthesized nanoceria and highlights the level of detail required to accurately report and interpret such studies. Additionally, AgCNPs are estimated to contain much less silver (0.22 parts per billion, ppb) than the amount of Ag+ needed to achieve comparable larvicidal activity (2.7 parts per million, ppm), potentially making these nanoceria ecofriendly. Finally, this work is the first study to demonstrate the until-now-unappreciated impacts of nanoceria on life history traits and interference with mosquito egg development.
有效控制病媒蚊种群，同时避免抗药性的产生，仍然是综合病媒管理中普遍存在且日益增加的障碍。虽然金属纳米粒子在通过不太可能引发抗药性的机制来控制幼虫种群方面表现出了前景，但这些粒子对蚊子生活史特征和繁殖力的影响仍研究不足。在此，我们研究了化学定义明确的氧化铈纳米粒子（CNPs）和掺银纳米氧化铈（AgCNPs）对埃及伊蚊幼虫的杀幼虫潜力以及对生活史特征和繁殖力的影响。当 3 龄幼虫在没有幼虫食物的情况下暴露于纳米氧化铈时，死亡率计数显示 AgCNPs 比 CNPs 具有显著的活性（分别为 57.8±3.68%和 17.2±2.81%的致死率），并且与 Ag+对照物的活性相当（62.8±3.60%的致死率）。存活的幼虫表现出改变的生活史特征（例如，卵孵化比例降低和性别比例变化），表明这些纳米氧化铈的活性不仅限于杀幼虫剂。在另一组实验中，使用共聚焦荧光显微镜研究了纳米氧化铈污染的血餐对卵母细胞生长和卵生成的影响，结果显示，在用 AgCNP 血餐喂养后 16-24 小时，一些蚊子的卵母细胞生长停止，从而显著减少了平均卵簇。当幼虫食物不存在时，AgCNPs 导致 3 龄幼虫约 60%的死亡率，而 CNPs 仅导致约 20%的死亡率，这与之前关于绿色合成纳米氧化铈的报告形成对比，突出了准确报告和解释此类研究所需的详细程度。此外，AgCNPs 估计含有比实现类似杀幼虫活性所需的 Ag+（2.7 ppm）少得多的银（0.22 十亿分率，ppb），这可能使这些纳米氧化铈具有生态友好性。最后，这项工作是第一项证明纳米氧化铈对生活史特征的影响以及对蚊子卵发育的干扰的研究。
