Higher Institution Centre of Excellence (HICoE), Tropical Infectious Diseases Research and Education Centre (TIDREC), Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
Center of Insect Vector Study, Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Sci Rep. 2023 Jan 2;13(1):4. doi: 10.1038/s41598-022-25387-9.
A potentially novel actinobacterium isolated from forest soil, Streptomyces sp. KSF103 was evaluated for its insecticidal effect against several mosquito species namely Aedes aegypti, Aedes albopictus, Anopheles cracens and Culex quinquefasciatus. Mosquito larvae and adults were exposed to various concentrations of the ethyl acetate (EA) extract for 24 h. Considerable mortality was evident after the EA extract treatment for all four important vector mosquitoes. Larvicidal activity of the EA extract resulted in LC at 0.045 mg/mL and LC at 0.080 mg/mL for Ae. aegypti; LC at 0.060 mg/mL and LC at 0.247 mg/mL for Ae. albopictus; LC at 2.141 mg/mL and LC at 6.345 mg/mL for An. cracens; and LC at 0.272 mg/mL and LC at 0.980 mg/mL for Cx. quinquefasciatus. In adulticidal tests, the EA extract was the most toxic to Ae. albopictus adults (LD = 2.445 mg/mL; LD = 20.004 mg/mL), followed by An. cracens (LD = 5.121 mg/mL; LD = 147.854 mg/mL) and then Ae. aegypti (LD = 28.873 mg/mL; LD = 274.823 mg/mL). Additionally, the EA extract exhibited ovicidal activity against Ae. aegypti (LC = 0.715 mg/mL; LC = 6.956 mg/mL), Ae. albopictus (LC = 0.715 mg/mL; LC = 6.956 mg/mL), and An. cracens (LC = 0.715 mg/mL; LC = 6.956 mg/mL), evaluated up to 168 h post-treatment. It displayed no toxicity on the freshwater microalga Chlorella sp. Beijerinck UMACC 313, marine microalga Chlorella sp. Beijerinck UMACC 258 and the ant Odontoponera denticulata. In conclusion, the EA extract showed promising larvicidal, adulticidal and ovicidal activity against Ae. aegypti, Ae. albopictus, An. cracens, and Cx. quinquefasciatus (larvae only). The results suggest that the EA extract of Streptomyces sp. KSF103 has the potential to be used as an environmental-friendly approach in mosquito control. The current study would serve as an initial step toward complementing microbe-based bioinsecticides for synthetic insecticides against medically important mosquitoes.
从森林土壤中分离得到的一种具有潜在新颖性的链霉菌，即链霉菌 sp. KSF103，其对几种蚊子（埃及伊蚊、白纹伊蚊、致倦库蚊和三带喙库蚊）的杀虫效果进行了评估。将幼虫和成虫暴露于不同浓度的乙酸乙酯（EA）提取物中 24 小时。四种重要病媒蚊子经 EA 提取物处理后均出现明显死亡。EA 提取物的杀幼虫活性导致 Ae. aegypti 的 LC at 0.045 mg/mL 和 LC at 0.080 mg/mL；Ae. albopictus 的 LC at 0.060 mg/mL 和 LC at 0.247 mg/mL；An. cracens 的 LC at 2.141 mg/mL 和 LC at 6.345 mg/mL；Cx. quinquefasciatus 的 LC at 0.272 mg/mL 和 LC at 0.980 mg/mL。在成虫杀蚊试验中，EA 提取物对白纹伊蚊成虫（LD = 2.445 mg/mL；LD = 20.004 mg/mL）毒性最大，其次是致倦库蚊（LD = 5.121 mg/mL；LD = 147.854 mg/mL），然后是埃及伊蚊（LD = 28.873 mg/mL；LD = 274.823 mg/mL）。此外，EA 提取物对埃及伊蚊（LC = 0.715 mg/mL；LC = 6.956 mg/mL）、白纹伊蚊（LC = 0.715 mg/mL；LC = 6.956 mg/mL）和致倦库蚊（LC = 0.715 mg/mL；LC = 6.956 mg/mL）具有杀卵活性，在处理后 168 小时内进行评估。它对淡水微藻 Chlorella sp. Beijerinck UMACC 313、海洋微藻 Chlorella sp. Beijerinck UMACC 258 和蚂蚁 Odontoponera denticulata 没有毒性。总之，EA 提取物对埃及伊蚊、白纹伊蚊、致倦库蚊和三带喙库蚊（幼虫）具有潜在的杀幼虫、杀成虫和杀卵活性。结果表明，链霉菌 sp. KSF103 的 EA 提取物具有作为蚊虫控制的环保方法的潜力。本研究将作为补充基于微生物的生物杀虫剂对抗医学重要蚊子的合成杀虫剂的初步步骤。
