Abstract
Bacillus thuringiensis is the most commonly used entomopathogen in the control of Aedes aegypti, which is a vector for different etiological agents that cause serious infections in humans. Several studies aim to isolate strains of this bacterium from different environments, with the perspective of selecting isolates with larvicidal activity for mosquitoes. Aiming at the insecticidal action of B. thuringiensis, the present study aimed to prospect B. thuringiensis of restinga and mangrove soils from the state of Maranhão, Brazil, with toxic potential for use in the biological control of Ae. aegypti. Bioassays were performed to determine the entomopathogenic activity of the bacilli against Ae. aegypti and lethal concentrations (LC50 and CL90) were estimated after the tests. Polymerase Chain Reaction and SDS-PAGE techniques were performed to verify the gene and protein content of the isolates, respectively. The soil of the mangrove and restinga ecosystems showed potential for obtaining B. thuringiensis. This isolate, in addition to having proteins with molecular mass similar to the toxins Cry and Cyt, also presented several diptera-specific genes cry and cyt, demonstrating that it has high potential to be used in the biological control of Ae. aegypti.
Highlights
The Aedes (Stegomyia) aegypti (Linnaeus 1762), considered a cosmopolitan mosquito, is widely distributed among tropical and subtropical regions
The present study investigated the toxicity, the protein content and genic content of one B. thuringiensis isolate against Ae. aegypti larvae, obtained from the restinga ecosystem, to the search for a lineage with genetic variability greater than B. thuringiensis var. israelensis (Bti)
The soil of the mangrove and restinga ecosystems showed a potential to obtain this bacilli, with high variation of the B. thuringiensis index regarding the soil samples of the ecosystems of which they were isolated, being the average B. thuringiensis index of 0.81. This index showed that the restinga and mangrove soil had the potential to prospect the B. thuringiensis
Summary
The Aedes (Stegomyia) aegypti (Linnaeus 1762), considered a cosmopolitan mosquito, is widely distributed among tropical and subtropical regions This mosquito is the main vector for DENV, ZIKA and CHIKV arbovirus, which unleash infections in human, such as dengue fever, zika fever and chikungunya fever, respectively (Gubler and Clark, 1995; Donalisio and Freitas, 2015; Vasconcelos, 2015; Valle et al, 2016; Roundy et al, 2017; Brasil, 2020). These arboviruses currently represent one of the biggest public health problems in Brazil, because the vector shows a broad spread among its territory (Brasil, 2020). The Bacillus thuringiensis (Berliner, 1911) is an important insects’ pathogen and exhibits high toxicity for diptera larvae (Campanini et al, 2012; Soares-da-Silva et al, 2017; Lobo et al, 2018; Zghal et al, 2018; Viana et al, 2020)
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Schedule a callMore From: Brazilian journal of biology = Revista brasleira de biologia
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