ABSTRACT The objectives of this study were to genotype single nucleotide polymorphisms (SNP) AF159246:g.2959A>G (CAST/DdeI) and AF248054.2:g.6545C>T (CAPN4751) in beef cattle by PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Length Polymorphism), using the restriction enzyme DdeI for both SNP, and describe the use of these genotyping methodologies for the first time. For the SNP located in the CAST gene, new primers were designed, and for the SNP of the CAPN1 gene, the same primers previously described in the literature were used. Bonsmara, Caracu, Senepol, Nelore, and Angus bulls were chosen from among the most used bulls in breeding programs according to their genealogy and the lowest possible degree of parentage between them to ensure an experimental sample representative of the genetic variability in each breed. For the CAST and CAPN1 genes, respectively, the following number of animals were analyzed: Bonsmara (n = 25/22), Caracu (n = 25/26), Senepol (n = 25/24), Nelore (n = 26/26), and Angus (n = 25/24). The accuracy of these methodologies was confirmed by direct sequencing of PCR products generated for the two polymorphisms. The new primers developed for CAST/DdeI SNP detection and the use of DdeI enzyme for CAPN4751 SNP detection were effective in genotyping, since no inconclusive genotypes were observed for these genes. Thus, the genotyping of beef cattle using the PCR-RFLP technique for CAST and CAPN1 genes is robust, relatively inexpensive, and easy to perform in any basic molecular biology laboratory. If the association of these markers with traits of economic interest in beef cattle is confirmed in new studies, these methodologies may contribute to the selection of animals with superior genetics, i.e., with the potential to produce better-quality meat, either by marker-assisted selection or by the inclusion of these polymorphisms in high-density marker panels.

Resumo O carrapato Rhipicephalus microplus é responsável por perdas significativas no agronegócio. O controle deste carrapato é feito principalmente por meio da aplicação de acaricidas químicos, geralmente resultando na contaminação de produtos de origem animal e do meio ambiente. Outra preocupação importante associada ao uso de acaricidas é o crescente aumento de relatos sobre a resistência deste carrapato a princípios ativos de vários produtos comerciais. Uma alternativa de controle é por meio de vacinação. Porém, a vacina comercializada contendo proteína homóloga à Bm86, apresenta variações de eficácia em relação às diferentes localizações geográficas. Este estudo buscou identificar determinantes antigênicos das sequencias de proteínas homólogas a Bm86. As análises filogenéticas foram feitas para determinar a extensão da divergência entre diferentes populações de R. microplus com o objetivo de identificar a sequência que poderia ser usada como vacina universal contra as múltiplas populações geograficamente distintas de R. microplus e espécies de carrapatos relacionados. Considerando-se a extensa sequência e o polimorfismo observados entre linhagens de R. microplus de diferentes regiões geográficas, podemos concluir que pode ser possível obter uma vacinação efetiva contra esses carrapatos bovinos utilizando um único antígeno universal baseado em Bm86.

Abstract The cattle tick Rhipicephalus microplus causes significant economic losses in agribusiness. Control of this tick is achieved mainly through the application of chemical acaricides, often resulting in contamination of animal food products and of the environment. Another major concern associated with acaricide use is the increasing reports of resistance of this tick vector against the active ingredients of many commercial products. An alternative control method is vaccination. However, the commercially available vaccine based on a protein homologous to Bm86 exhibits variations in efficacy relative to the different geographical locations. This study aimed to identify antigenic determinants of the sequences of proteins homologous to Bm86. Phylogenetic analyses were performed to determine the extent of divergence between different populations of R. microplus to identify the sequence that could be used as a universal vaccine against the multiple geographically distinct populations of R. microplus and related tick species. Considering the extensive sequence and functional polymorphism observed among strains of R. microplus from different geographical regions, we can conclude that it may be possible to achieve effective vaccination against these cattle ticks using a single universal Bm86-based antigen.

Resumo O objetivo deste trabalho foi avaliar a diversidade de carrapatos associados à animais de vida livre e investigar novos registros de hospedeiros. Coletas foram feitas em animais resgatados durante a cheia do Rio Jamari, localizado no município de Ariquemes, estado de Rondônia, Região Norte do Brasil. Um total de 39 animais foi capturado, dos quais dez eram anfíbios, 19 eram répteis e dez eram mamíferos. 127 carrapatos do gênero Amblyomma foram coletados destes animais, distribuídos em sete espécies: Amblyomma dissimile , Amblyomma geayi, Amblyomma humerale, Amblyomma longirostre, Amblyomma nodosum, Amblyomma rotundatum e Amblyomma varium. Adicionalmente, um exemplar de Rhipicephalus (Boophilus) microplus foi coletado. Dentre estes espécimes, 85 eram adultos e 42 eram ninfas, com A. rotundatum sendo a espécie mais prevalente. Uma larva de Amblyomma spp. também foi coletada de um lagarto (Uranoscodon superciliosus), um Amblyomma calcaratum e um Amblyomma dubitatum foram recuperados do ambiente, assim totalizando 130 carrapatos. Dentre os ixodídeos coletados de diferentes hospedeiros, este trabalho fornece o primeiro registro da espécie A. rotundatum parasitando Rhinella major, U. superciliosus, Leptophis ahaetulla, Chironius multiventris e Mastigodryas boddaerti, assim como da espécie A. humerale parasitando U. superciliosus , a espécie A. geayi parasitando Choloepus didactylus e R. microplus parasitando Alouatta puruensis .

Abstract The objective of this work was to evaluate the diversity of ticks associated with free-living animals and to investigate new host records for ticks. Ticks were collected from animals rescued during the flood of the Jamari River in the municipality of Ariquemes, state of Rondônia, North Region of Brazil. A total of 39 animals were captured, out of which 10 were amphibians, 19 were reptiles and 10 were mammals. A total of 127 ticks of the Amblyomma genus were collected from these animals, distributed among seven species: Amblyomma dissimile, Amblyomma geayi, Amblyomma humerale , Amblyomma longirostre, Amblyomma nodosum , Amblyomma rotundatum and Amblyomma varium. In addition, one specimen of Rhipicephalus (Boophilus) microplus was collected. Among these specimens, 85 were adults and 42 were nymphs, with A. rotundatum being the most prevalent species. An Amblyomma spp. larvae was also collected from a lizard (Uranoscodon superciliosus), and one Amblyomma calcaratum and one Amblyomma dubitatum were recovered from the environment, thus totaling 130 ticks. Among the Ixodidae collected from different hosts, we provide the first report for the species A. rotundatum parasitizing Rhinella major, U. superciliosus, Leptophis ahaetulla, Chironius multiventris, and Mastigodryas boddaerti, as well as of A. humerale parasitizing U. superciliosus, A. geayi parasitizing Choloepus didactylus, and Rhipicephalus (B.) microplus parasitizing Alouatta puruensis.

Resumo Carrapatos do complexo R. (B.) microplus se distribuem em cinco taxa: R. australis, R. annulatus, R. (B.) microplus clado A sensu R. microplus clado B sensue e R. (B.) microplus clado C sensu. Métodos baseados no DNA mitocondrial podem auxiliar taxonomistas quando há dificuldades em estabelecer diferenças morfológicas para distinguir membros do complexo R. (B.) microplus. O objetivo deste estudo foi a caracterização molecular e a inferência de relações filogenéticas em carrapatos de todas as cinco regiões geográficas do Brasil. Para o gene COX-1, a análise molecular caracterizou 10 haplótipos. Na análise molecular em rede foi observado que o haplótipo H-2 é o mais disperso entre as populações (n=11). O haplótipo H-3 (n=2) foi o que obteve maior diferenciação genética ao ser comparado com outras populações brasileiras. A árvore filogenética Bayesiana de gene COX-1 gerou suporte robusto e foi observado que a população de R. (B.) microplus haplótipo H-3 apresentou ramificação com divergência entre as outras populações brasileiras apresentadas neste estudo. Conclui-se que as populações brasileiras possuem diversidade haplotípica com divergência entre as diversas populações de R. (B.) microplus no Brasil.

Abstract The Rhipicephalus (Boophilus) microplus complex currently consists of five taxa, namely R. australis, R. annulatus, R. (B.) microplus clade A sensu, R. microplus clade B sensu, and R. (B.) microplus clade C sensu. Mitochondrial DNA-based methods help taxonomists when they are facing the morpho-taxonomic problem of distinguishing members of the R. (B.) microplus complex. The purpose of this study was to perform molecular characterization of ticks in all five regions of Brazil and infer their phylogenetic relationships. Molecular analysis characterized 10 haplotypes of the COX-1 gene. Molecular network analysis revealed that haplotype H-2 was the most dispersed of the studied populations (n = 11). Haplotype H-3 (n = 2) had the greatest genetic differentiation when compared to other Brazilian populations. A Bayesian phylogenetic tree of the COX-1 gene obtained strong support. In addition, it was observed that the population of R. (B.) microplus haplotype H-3 exhibited diverging branches among the other Brazilian populations in the study. The study concludes that the different regions of Brazil have R. (B.) microplus tick populations with distinct haplotypes.

The objective of the present study was to estimate the allelic and genotypic frequencies of the polymorphisms E2FB (AY138588.1: c.305C> T), located in the leptin gene (LEP), and TG5 (X05380.1:g.-422C>T), located in the thyroglobulin gene (TG), and evaluate the association of these polymorphisms in crossbred cattle of seven distinct genetic groups with the following traits: slaughter weight (SW), hot carcass weight (HCW), hot carcass yield (HCY), carcass fat thickness (CFT), ribeye area (REA), marbling (MARM) and shear force (SF). The animals were genotyped using the PCR-RFLP (Polymorphism Chain Reaction-Restriction Fragment Length Polymorphism) technique, using 201 products obtained from F1 Caracu × Nellore, Angus × Nellore and Valdostana × Nellore cows, mated to Canchim, Caracu and Red Angus bulls (only Caracu × Nellore cows were used with Red Angus bulls). The allelic and genotypic frequencies were compared using the Chi-squared test. Associations between the genotype of each polymorphism and the traits were analyzed using the General Linear Model (GLM) of statistical software SAS. The least squares means of genotypes of the polymorphisms were compared using Student's t test. The E2FB polymorphism in the LEP gene was associated with CFT, showing the potential for use in national programs for genetic improvement of beef cattle, through the inclusion of SNP in genotyping commercial tests. The TG5 polymorphism in the TG gene was not associated with any of the evaluated traits and was considered ineffective for selection of beef cattle in Brazilian herds.