Abstract
Entomopathogenic agents are viable and effective options due to their selective action against insects but benign effects on humans and the environment. The most promising entomopathogens include subspecies of Bacillus thuringiensis (Bt), which are widely used for the biological control of insects, including mosquito vectors of human pathogens. The efficacy of B. thuringiensis toxicity has led to the search for new potentially toxic isolates in different regions of the world. Therefore, soil samples from the Amazon, Cerrado and Caatinga biomes of the state of Maranhão were evaluated for their potential larvicidal action against Aedes aegypti. The isolates with high toxicity to mosquito larvae, as detected by bioassays, were subjected to histological evaluation under a light microscope to identify the genes potentially responsible for the toxicity. Additionally, the toxic effects of these isolates on the intestinal epithelium were assessed. In the new B. thuringiensis isolates toxic to A. aegypti larvae, cry and cyt genes were amplified at different frequencies, with cry4, cyt1, cry32, cry10 and cry11 being the most frequent (33-55%) among those investigated. These genes encode specific proteins toxic to dipterans and may explain the severe morphological changes in the intestine of A. aegypti larvae caused by the toxins of the isolates.
Highlights
Aedes (Stegomyia) aegypti (L. 1762) is an important vector of the viruses that cause dengue fever, urban yellow fever, chikungunya and Zika fever
The most frequent genes were cry32 and cyt1, which were present in 56% of the new Bacillus thuringiensis (Bt) isolates, followed by the cry11 and cyt2 genes (44%) and the cry4 gene (33%)
Different profiles of toxic cry and cyt genes were detected among the evaluated Bt isolates, with a minimum of one and a maximum of five of the nine classes of the analysed genes
Summary
Aedes (Stegomyia) aegypti (L. 1762) is an important vector of the viruses that cause dengue fever, urban yellow fever, chikungunya and Zika fever. 1762) is an important vector of the viruses that cause dengue fever, urban yellow fever, chikungunya and Zika fever This mosquito is anthropophilic and domestic, with diurnal haematophagic activity (Consoli and Lourenço-de-Oliveira, 1994; Vasconcelos, 2015; Valle et al, 2016; Montagner et al, 2018), and its adaptive success is associated with favourable domestic or peridomestic conditions, such as the presence of humans and aquatic breeding sites; rapid development and eggs that are resistant to desiccation (Zara et al, 2016; Carvalho and Moreira, 2017; Bassani et al, 2019). It is necessary to search for alternative methods of reducing the population size of this vector, such as the use of entomopathogenic bacteria (Carvalho and Moreira, 2017; Moyes et al, 2017; Aponte et al, 2019)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
