Sujitha Vasu, Murugan Kadarkarai, Dinesh Devakumar, Pandiyan Amuthvalli, Aruliah Rajasekar, Hwang Jiang-Shiou, Kalimuthu Kandasamy, Panneerselvam Chellasamy, Higuchi Akon, Aziz Al Thabiani, Kumar Suresh, Alarfaj Abdullah A, Vaseeharan Baskaralingam, Canale Angelo, Benelli Giovanni
Department of Zoology, Bharathiar University, Coimbatore 641 046, India.
Department of Zoology, Bharathiar University, Coimbatore 641 046, India; Thiruvalluvar University, Vellore, 632 115, India.
Aquat Toxicol. 2017 Jul;188:100-108. doi: 10.1016/j.aquatox.2017.04.015. Epub 2017 Apr 25.
Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensi and A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparum parasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV-vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC of V. pachynema extract was 58.1μg/ml (CQ-s) and 71.46μg/ml (CQ-r), while nano-CdS IC was 76.14μg/ml (CQ-s) and 89.21μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of CdS nanoparticles and Cd ions in aqueous solution was also assessed in mud crabs, showing higher toxicity of aqueous Cd ions if compared to nano-CdS. Overall, our results underlined the efficacy of green-synthesized CdS nanoparticles in malaria vector control, outlining also significant impacts on the enzymatic activity of non-target aquatic organisms, with special reference to mud crabs.
目前，纳米配方的杀蚊幼虫剂已被广泛提议用于控制疟疾病媒种群的幼龄阶段。然而，纳米颗粒在水生环境中的归宿却鲜为人知，特别是纳米颗粒对非靶标水生无脊椎动物酶活性的影响。在本研究中，我们采用一种绿色方法，利用厚叶藻廉价提取物合成了硫化镉纳米颗粒。硫化镉纳米颗粒对疟疾病媒斯氏按蚊和苏门答腊按蚊的幼龄阶段显示出高毒性。研究了该纳米合成产品对氯喹抗性（CQ-r）恶性疟原虫寄生虫的抗疟活性。从非靶标角度出发，我们重点关注了这种新型纳米农药对锯缘青蟹抗氧化酶乙酰胆碱酯酶（AChE）和谷胱甘肽S-转移酶（GST）活性的影响。通过紫外可见光谱、傅里叶变换红外光谱以及扫描电子显微镜和X射线衍射分析对纳米材料进行了表征。在杀蚊试验中，厚叶藻合成的硫化镉纳米颗粒对斯氏按蚊的致死浓度范围为16.856（一龄幼虫）至30.301μg/ml（蛹），而对苏门答腊按蚊则为13.584至22.496μg/ml。评估了厚叶藻提取物和硫化镉纳米颗粒对恶性疟原虫CQ-r和CQ-敏感（CQ-s）菌株的抗疟活性。厚叶藻提取物对CQ-s菌株的半数抑制浓度（IC）为58.1μg/ml，对CQ-r菌株为71.46μg/ml，而纳米硫化镉的IC分别为76.14μg/ml（CQ-s）和89.21μg/ml（CQ-r）。在酶活性测定中，将锯缘青蟹暴露于亚致死浓度，即4、6和8μg/ml的硫化镉纳米颗粒中，评估16天后GST和AChE活性的变化。在整个实验期间，与对照组相比，我们观察到GST活性显著更高。此外，单次用硫化镉纳米颗粒处理导致AChE活性随时间显著降低。还评估了水溶液中硫化镉纳米颗粒和镉离子对锯缘青蟹的毒性，结果表明与纳米硫化镉相比，水溶液中的镉离子毒性更高。总体而言，我们的结果强调了绿色合成的硫化镉纳米颗粒在控制疟疾病媒方面的功效，同时也概述了其对非靶标水生生物酶活性的显著影响，特别是对锯缘青蟹的影响。
