title: Extracellular synthesis of silver nanoparticles using Bacillus megaterium against malarial and dengue vector (Diptera: Culicidae).
abstract: Biosynthesis of silver nanoparticles has provoked nowadays and alternative to physical and chemical approaches. In the present study, silver nanoparticles (AgNPs) were synthesized extracellular method using Bacillus megaterium. The AgNPs formations were confirmed initially through color change, and the aliquots were characterized through UV-visible spectrophotometer, followed by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared (FTIR) spectra. The surface plasmon resonance band was shown at 430 nm in UV-vis spectrophotometer. The bioreduction was categorized through identifying the compounds responsible for the AgNP synthesis, and the functional group present in B. megaterium cell-free culture was scrutinized using FTIR. The topography and morphology of the particles were determined using SEM. In addition, this biosynthesized AgNPs were found to show higher insecticidal efficacy against vector mosquitoes. The LC50 and LC90 were found to be 0.567, 2.260; 0.90, 4.44; 1.349, 8.269; and 1.640, 9.152 and 0.240, 0.955; 0.331, 1.593; 0.494, 2.811; and 0.700, 4.435 with respect to the first, second, third, and fourth instar larvae of Culex quinquefasciatus and Aedes aegypti. All the calculated χ (2) values are highly significant compared with the tabulated value. Therefore, B. megaterium-synthesized silver nanoparticles would be used as a potent larvicidal agent against Cx. quinquefasciatus and Ae. aegypti.
authors.affiliation: Department of Zoology, M.K.M. Group of Colleges, Hodal, Haryana, India. najirila2010@gmail.com.
authors.forename: A Najitha
authors.initials: AN
authors.lastname: Banu
authors.affiliation: Postgraduate and Research Department of Zoology, Thiagarajar College, Madurai, Tamil Nadu, India.
authors.forename: C
authors.initials: C
authors.lastname: Balasubramanian
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D001410:Bacillus megaterium / Q000378:metabolism*; D003465:Culex / Q000187:drug effects* / Q000254:growth & development; D003715:Dengue / Q000635:transmission; D007303:Insect Vectors / Q000187:drug effects* / Q000254:growth & development; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008288:Malaria / Q000635:transmission; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity; D008855:Microscopy, Electron, Scanning; D012834:Silver / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D020349:Surface Plasmon Resonance
chemical_list: D007306:Insecticides; D012834:Silver
keywords: Bacillus megaterium; Bioreduction; LC50 and LC90; Pathogenicity; Silver nanoparticle