| Autor: |
da Costa RA; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, SGAN 916, Brasília, DF 70790-160, Brazil., Dutra TTB; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, SGAN 916, Brasília, DF 70790-160, Brazil., Pereira Costa Andrade IE; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, SGAN 916, Brasília, DF 70790-160, Brazil., Monnerat RG; Laboratório de Bactérias Entomopatogênicas, Embrapa Recursos Genéticos e Biotecnologia, Av. W5 Norte, Brasília, DF 70770-917, Brazil., Barreto CC; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, SGAN 916, Brasília, DF 70790-160, Brazil., Dias SC; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, SGAN 916, Brasília, DF 70790-160, Brazil.; Graduate Program in Animal Biology, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF 70910-900, Brazil. |
| Abstrakt: |
Aedes aegypti and Culex quinquefasciatus are vectors of numerous diseases of worldwide public importance, such as arboviruses and filariasis. The main strategy for controlling these vectors is the use of chemicals, which can induce the appearance of resistant insects. The use of Bacillus thuringiensis ( Bt ) and Lysinibacillus sphaericus ( Ls ) with larvicidal activity against arboviral-transmitting insects has been successful in many studies. In contrast, the use and knowledge of peptides with insecticidal activity are so far scarce. In this work, 25 peptides and 5 strains of each bacterial species were prospected individually or together regarding their insecticidal activity. Initially, in vitro assays of cellular cytotoxicity of the peptides against SF21 cells of Spodoptera frugiperda were performed. The peptides Polybia-MPII and pelgipeptin caused 69 and 60% of cell mortality, respectively, at the concentration of 10 μM. Thus, they were evaluated in vivo against second-stage larvae of the two Culicidae. However, in the in vivo bioassays, only pelgipeptin showed larvicidal mortality against both larvae (LC 50 6.40 μM against A. aegypti , and LC 50 1.22 μM against C. quinquefasciatus ). The toxin-producing bacterial strain that showed the lowest LC 50 against A. aegypti was Bt S8 (LC 50 = 0.71 ng/mL) and against C. quinquefasciatus , it was Ls S260 (LC 50 = 2.32 ng/mL). So, the synergistic activity between the association of the bacterial toxins and pelgipeptin was evaluated. A synergic effect of pelgipeptin was observed with Ls strain S260 against C. quinquefasciatus . Our results demonstrate the possibility of synergistic or individual use of both biologically active larvicides against C. quinquefasciatus and A. aegypti . |
