RESUMO
Bovine leukaemia virus (BLV) is an oncogenic member of the genus Deltaretrovirus of the family Retroviridae. Recent studies revealed that BLV strains can be classified into six different genotypes and raised the possibility that another genotype may exist. In order to gain insight into the degree of genetic variability of BLV strains circulating in the South American region, a phylogenetic analysis was performed using gp51 env gene sequences. The results of these studies revealed the presence of seven BLV genotypes in this geographic region and the suitability of partial gp51 env gene sequences for phylogenetic inference. A significant number of amino acid substitutions found in BLV strains isolated in South America map to the second neutralization domain of gp51. A 3D molecular model of BLV gp51 revealed that these substitutions are located on the surface of the molecule. This may provide a selective advantage to overcome immune host neutralization.
Assuntos
Leucose Enzoótica Bovina/virologia , Vírus da Leucemia Bovina/classificação , Vírus da Leucemia Bovina/isolamento & purificação , Polimorfismo Genético , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Animais , Bovinos , Análise por Conglomerados , Epitopos/genética , Produtos do Gene env/genética , Genótipo , Vírus da Leucemia Bovina/genética , Modelos Moleculares , Dados de Sequência Molecular , Filogenia , Estrutura Terciária de Proteína , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência , América do SulRESUMO
Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV causes a wide range of diseases in humans, from the acute febrile illness dengue fever (DF) to life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). There is not knowledge of the genetic relations among DENV circulating in Ecuador. Given the emerging behaviour of DENV, a single tube RT-PCR assay using a pair of consensus primers to target the NS5 coding region has been recently validated for rapid detection of flaviviruses. In order to gain insight into the degree of genetic variation of DENV strains isolated in Ecuador, DENV NS5 sequences from 23 patients were obtained by direct sequencing of PCR fragments using the mentioned one step RT-PCR assay. Phylogenetic analysis carried out using the 23 Ecuadorian DENV NS5 sequences, as well as 56 comparable sequences from DENV strains isolated elsewhere, revealed a close genetic relation among Ecuadorian strains and DENV isolates of Caribbean origin. The use of partial NS5 gene sequences may represent a useful alternative for a rapid phylogenetic analysis of DENV outbreaks.