This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

Este trabalho objetivou-se selecionar e identificar estirpes de Bacillus thuringiensis (Bt) obtidos de amostras de solo do estado de Tocantins que apresentaram toxicidade para o mosquito Aedes aegypti. Obteve-se isolados de Bt das amostras de solos obtidos e com maior número de colônias em solos com alto teor de argila e matéria orgânica. A atividade tóxica entre os isolados obtidos variou de 14,7 a 98% de mortalidade para larvas de 2o estádio de A. aegypti, com destaque para o isolado A-392. Foram realizadas analise de SDS-PAGE onde houve a presença de um peptídeos de aproximadamente 80 kDa, não sendo visualizado nos demais isolados, o a estirpe A-392 teve 98% de mortalidade das larvas de A. aegypti testadas, no período de 48 horas, utilizando uma concetração de 20 mL/mL do caldo bacteriano. Verifica-se que B. Thuringiensis isoladas do estado do Tocantins apresenta resultados promissores para serem utilizadas na fabricação de um bioinseticidas contra as larvas deste mosquito.

No abstract

Aedes aegypti (Diptera: Culicidae) is the main vector of Dengue, Zika and Chikungunya, diseases that have attracted the attention of scientific society and the population in general, due to epidemiological outbreaks and numerous health hazards and the imminent risk of death. Much has been discussed about more efficient forms of control for this mosquito, considering that the chemical control, currently used, has been causing impacts on the environment and the health of the population. Thus, alternative methods have been evaluated. Among them, biological control through products formulated from Bacillus thuringiensis has stood out, as biotechnological advances have allowed to improve and enhance the products already on the market, as well as to develop new bioinsecticides from the entomopathogenic proteins produced by these microorganisms, aiming to make the larvae control more and more effective. To this end, this study aimed to carry out a bibliographic survey on the use of Bacillus thuringiensis as a form of biological control of Aedes aegypti larvae, due to the need to use safer and more effective methods of control for disease vector insects.

In the title compound, C11H9FN2O3, the benzene ring is almost coplanar with the heterocyclic ring, making a dihedral angle of 14.0 (1)°. The plane of the carboxyl group is rotated by 14.7 (3)° with respect to the 1,2,4-oxadiazole ring plane. The aliphatic chain exhibits a standard zigzag arrangement. Two inter­molecular O—H⋯O hydrogen bonds between the carboxyl groups related by an inversion centre promote a dimeric structure formation. The dimers are stacked along the crystallographic a axis.