Identificação de domínios conservados associados a resistência a acaricidas em Amblyomma sculptum (Acari: Ixodidae)

Abstract

This is the first study that identifies conserved domains related to the resistance to acaricides in Amblyomna sculptum. On the raising of equines, the control of A. sculptum is one of the biggest challenges to the living stock raisers. There is no study in the literature that tries to explain the molecular mechanisms and their components involved on the development of chemical resistance in A. sculptum. Therefore, the objective of this work was to identify conserved domains related to the resistance to the two most commonly used chemical bases in the control of A. sculptum, the pyrethroids and organophosphates. This work was developed in two stages. The first one comprehended an observational research, with the application of a semi-structured form for the characterization of properties and living stock raisers, and for the acaricides-handling as well. On the second stage, the experimental one, molecular biology techniques were done in order to identify the conserved domains related to the chemical resistance in A. sculptum. 24 specimens of A. sculptum were collected, from naturally infested living stock in properties of southern Minas Gerais. The form was applied on those properties. For the molecular analysis, the 24 A. sculptum specimens had their total RNA extracted, followed by the cDNA synthesis. For the PCR, four pairs of primers were synthesized. On the Primer Blast software it was obtained four pairs of primers; two pairs related to the resistance to organophosphate and two pairs related to the resistance to pyrethroids. The PCR, for each pair of primer, was done using the cDNA of the 24 specimens, totalizing 48 samples for each chemical base.The PCR results were subjected to electrophoresis. For the sequencing, it was sent 20 parts. It was noticed a great similarity on the profile of the living stock raisers, as well as for the characterization of property, A. sculptum handling and control. All rliving stock raisers did the control with the application of some anti-tick product, with the pyrethroids as the most used chemical group. Most of the interviewees seems to confound the cycle and control of A. sculptum with the Rhipicephalus microplus and with Dermacentornitens, which is problematic. When it comes to the molecular analysis, the obtained result was 29 positive samples to the region associated to the resistance to organophosphate and 32 positive samples to pyrethroids. After data analysis, it was done a search for conserved domains in the Conserved Domain Database (CDD) at NCBI. Related to the sequences of A. sculptum, it was identified two domains, both members of the superfamily of ABC transporters. The presence of this superfamily suggests that the studied species might present specific genic regions related to the resistance to acaricides based on pyrethroids and organophosphates. This thesis is organized in two parts, with the first one concerning the theoretic referential and the second part contenting the scientific article reporting the methodology and the found results.