| Author | Carvalho, Karine da Silva | |
| Author | Crespo, Mônica Maria | |
| Author | Araújo, Ana Paula | |
| Author | Silva, Renata Santana da | |
| Author | Melo-Santos, Maria Alice Varjal de | |
| Author | Oliveira, Cláudia Maria Fontes de | |
| Author | Silva-Filha, Maria Helena Neves Lobo | |
| Access date | 2019-03-28T12:22:38Z | |
| Available date | 2019-03-28T12:22:38Z | |
| Document date | 2018 | |
| Citation | CARVALHO, K. da S. et al. Long-Term Exposure of Aedes Aegypti to Bacillus Thuringiensis Svar. Israelensis Did Not Involve Altered Susceptibility to This Microbial Larvicide or to Other Control Agents. Parasites & Vectors, v. 11, n. 1, p. 673, 29 dez. 2018. | pt_BR |
| ISSN | 1756-3305 | pt_BR |
| URI | https://www.arca.fiocruz.br/handle/icict/32260 | |
| Language | eng | pt_BR |
| Rights | open access | pt_BR |
| Title | Long-term exposure of Aedes aegypti to Bacillus thuringiensis svar. israelensis did not involve altered susceptibility to this microbial larvicide or to other control agents | pt_BR |
| Type | Article | pt_BR |
| DOI | 10.1186/s13071-018-3246-1 | |
| Abstract | Background: Bacillus thuringiensis svar. israelensis (Bti) is an effective and safe biolarvicide to control Aedes aegypti.
Its mode of action based on four protoxins disfavors resistance; however, control in endemic areas that display high
mosquito infestation throughout the year requires continuous larvicide applications, which imposes a strong
selection pressure. Therefore, this study aimed to investigate the effects of an intensive Bti exposure on an Ae.
aegypti strain (RecBti), regarding its susceptibility to Bti and two of its protoxins tested individually, to other
control agents temephos and diflubenzuron, and its profile of detoxifying enzymes.
Methods: The RecBti strain was established using a large egg sample (10,000) from Recife city (Brazil) and more
than 290,000 larvae were subjected to Bti throughout 30 generations. Larvae susceptibility to larvicides and the
activity of detoxifying enzymes were determined by bioassays and catalytic assays, respectively. The Rockefeller
strain was the reference used for these evaluations.
Results: Bti exposure yielded an average of 74% mortality at each generation. Larvae assessed in seven time
points throughout the 30 generations were susceptible to Bti crystal (resistance ratio RR ≤ 2.8) and to its individual
toxins Cry11Aa and Cry4Ba (RR ≤ 4.1). Early signs of altered susceptibility to Cry11Aa were detected in the last
evaluations, suggesting that this toxin was a marker of the selection pressure imposed. RecBti larvae were also
susceptible (RR ≤ 1.6) to the other control agents, temephos and diflubenzuron. The activity of the detoxifying
enzymes α- and β-esterases, glutathione-S-transferases and mixed-function oxidases was classified as unaltered in
larvae from two generations (F19 and F25), except for a β-esterases increase in F25.
Conclusions: Prolonged exposure of Ae. aegypti larvae to Bti did not evolve into resistance to the crystal, and no
cross-resistance with temephos and diflubenzuron were recorded, which supports their sustainable use with Bti
for integrated control practices. The unaltered activity of most detoxifying enzymes suggests that they might not
play a major role in the metabolism of Bti toxins, therefore resistance by this mechanism is unlikely to occur. This
study also highlights the need to establish suitable criteria to classify the status of larval susceptibility/resistance. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Affilliation | Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil. | pt_BR |
| Subject | Cry11Aa | pt_BR |
| Subject | Cry4Ba | pt_BR |
| Subject | Temephos | pt_BR |
| Subject | Diflubenzuron | pt_BR |
| Subject | Detoxifying enzymes | pt_BR |
| Subject | Resistance | pt_BR |
| DeCS | Aedes / efeitos de drogas | pt_BR |
| DeCS | Animais | pt_BR |
| DeCS | Bacillus thuringiensis / crescimento e desenvolvimento | pt_BR |
| DeCS | Bacillus thuringiensis / patogenicidade | pt_BR |
| DeCS | Proteínas Bacterianas / Farmacologia | pt_BR |
| DeCS | Brasil | pt_BR |
| DeCS | Endotoxinas / farmacologia | pt_BR |
| DeCS | Proteínas Hemolisinas / Farmacologia | pt_BR |
| DeCS | Resistência a inseticidas | pt_BR |
| DeCS | Inseticidas / farmacologia | pt_BR |
| DeCS | Larva / efeitos de drogas | pt_BR |
| DeCS | Controle de Mosquitos / métodos | pt_BR |
| DeCS | Controle de Pragas Biológico / métodos | pt_BR |
