Baculovirus expression, biochemical characterization and organophosphate sensitivity of rBmAChE1, rBmAChE2, and rBmAChE3 of Rhipicephalus (Boophilus) microplus

A single nucleotide polymorphism in the acetylcholinesterase gene of the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae) is associated with chlorpyrifos resistance

“…Alternative target site resistance mechanisms not explored in this study might also rely on the amplification of modified AChEs as occurs in T. urticae and T. evansi (Kwon et al, 2010;Carvalho et al, 2012) or on mutations that affect multiple AChE loci with additive effects such as those observed in R. microplus (Temeyer et al, 2009(Temeyer et al, , 2010(Temeyer et al, , 2012. While the detection of homozygosity for the G119S substitution argues against the co-existence of duplicated sensitive and insensitive AChEs in chlorpyrifos-resistant strains, the role of multiple AChE loci in K. aberrans cannot be ruled out since the genome of the closely related phytoseiid M. occidentalis harbors at least six putative AChEs with lower amino acid identities (<34%) to those found in T. urticae.…”

Acetylcholinesterases of blood-feeding flies and ticks

“…Reverse-transcription PCR demonstrated that transcripts encoding each of the three BmAChEs were expressed in tick synganglia [18] and quantitative PCR demonstrated that each of the three BmAChE genes were present in multiple copies in genomic DNA [21]. Sequencing of cDNAs from individual ticks further demonstrated that multiple alleles were expressed in tick synganglia for each of the three BmAChEs.…”

“…A third cDNA presumptively encoding R. microplus AChE was reported [15], subsequently expressed in baculovirus for biochemical confirmation of identity as an AChE [16], and at least one mutation was shown to result in production of an altered AChE with decreased sensitivity to OP inhibition [17]. Further studies utilized baculovirus expression to produce enzymatically active recombinant protein for each of the three presumptively identified AChE cDNAs of R. microplus (BmAChE1, BmAChE2, and BmAChE3) and allowed biochemical confirmation that each of them encoded authentic AChEs [18]. The recombinant baculoviral constructs also confirmed that mutations in BmAChE1 and BmAChE3 produced OP-insensitive enzymes.…”

“…The recombinant baculoviral constructs also confirmed that mutations in BmAChE1 and BmAChE3 produced OP-insensitive enzymes. Genotyping surveys identified a number of mutations in each of the three confirmed BmAChEs that appeared to be associated with OP-resistant strains [17][18][19][20][21]. Identification of OP-insensitive mutations is important to allow development of molecular assays for rapid diagnosis of OP-resistance, to guide selection of control options, and to determine effects on enzyme structure and activity resulting from specific amino acid substitutions.…”

Bases moleculares da resistência a ivermectina em Rhipicephalus (Boophilus) microplus

“…O caráter multigênico da resposta a OP quando consideramos acetilcolinesterases foi reforçado por um trabalho onde foram identificados sete contigs com sequência similar a acetilcolinesterases (Bellgard et al, 2012). No mesmo sentido, em outro estudo foram expressos três transcritos similares a acetilcolinesterases isolados a partir de linhagens de R. microplus resistentes a OP (Temeyer et al, 2010). Mecanismos metabólicos também têm sido relacionados à resistência OP: quando linhagens suscetíveis e resistentes são expostas a coumaphous superexpressam transcritos similares a citocromo P450.…”