RESUMO
ABSTRACT The aim of this study was to perform the molecular characterization of conserved and variable regions of feline calicivirus capsid genome in order to investigate the molecular diversity of variants in Brazilian cat population. Twenty-six conjunctival samples from cats living in five public short-term animal shelters and three multicat life-long households were analyzed. Fifteen cats had conjunctivitis, three had oral ulceration, eight had respiratory signs (cough, sneeze and nasal discharge) and nine were asymptomatic. Feline calicivirus were isolated in CRFK cells and characterized by reverse transcription PCR target to both conserved and variable regions of open reading frame 2. The amplicons obtained were sequenced. A phylogenetic analysis along with most of the prototypes available in GenBank database and an amino acid analysis were performed. Phylogenetic analysis based on both conserved and variable region revealed two clusters with an aLTR value of 1.00 and 0.98 respectively and the variants from this study belong to feline calicivirus genogroup I. No association between geographical distribution and/or clinical signs and clustering in phylogenetic tree was observed. The variants circulating in public short-term animal shelter demonstrated a high variability because of the relatively rapid turnover of carrier cats constantly introduced of multiple viruses into this location over time.
Assuntos
Animais , Gatos , Doenças do Gato/virologia , Calicivirus Felino/isolamento & purificação , Calicivirus Felino/genética , Infecções por Caliciviridae/veterinária , Animais de Estimação/virologia , Filogenia , Brasil , Fases de Leitura Aberta , Genoma Viral , Calicivirus Felino/classificação , Infecções por Caliciviridae/virologia , Proteínas do Capsídeo/genéticaRESUMO
Bovine viral diarrhea virus (BVDV) is an etiologic agent that causes important economic losses in the world. It is endemic in cattle herds in most parts of the world. The purpose of this study was to evaluate the in vitro cytotoxic effect and antiviral properties of several marine natural products obtained from seaweeds: the indole alkaloid caulerpin (CAV, 1) and three diterpenes: 6-hydroxydichotoma-3,14-diene-1,17-dial (DA, 2), 10,18-diacetoxy-8-hydroxy-2,6-dolabelladiene (DB1, 3) and 8,10,18-trihydroxy-2,6-dolabelladiene (DB3, 4). The screening to evaluate the cytotoxicity of compounds did not show toxic effects to MDBK cells. The antiviral activity of the compounds was measured by the inhibition of the cytopathic effect on infected cells by plaque assay (PA) and EC50 values were calculated for CAV (EC=2,0± 5.8), DA (EC 2,8± 7.7), DB1 (EC 2,0±9.7), and DB3 (EC 2,3±7.4). Acyclovir (EC50 322± 5.9) was used in all experiments as the control standard. Although the results of the antiviral activity suggest that all compounds are promising as antiviral agents against BVDV, the Selectivity Index suggests that DB1 is the safest of the compounds tested.
RESUMO
A existência e o caráter de variantes ou subpopulaçöes derivadas de uma amostra padräo de vírus Sendai foram estudados, usando duas amostras de vírus Sendai selecionadas por técnica baseada na atividade de ligaçäo e receptores, a qual é apresentada por aqueles vírus. Foram estudados o comportamento biológico da neuraminidase de duas diferentes amostras Sendai de vírus parainfluenza tipo 1, sua pH-dependência, cálcio-dependência e relaçäo com as capacidades hemaglutinante e hemolítica. Foi observado que ambas as amostras, aquela considerada como semelhante à padräo e aquela obtida por propagaçäo de subpopulaçäo adsorvida à eritrócitos, mostravam mais significativas atividades hemaglutinante e sialidásica em valores de pH entre 5.0 e 7.0. A amostra considerada como semelhante à padräo, embora näo mostrasse qualquer atividade hemaglutinante frente a hemácias humanas do grupo O, era capaz de mostrar uma atividade sialidásica significativa. A atividade sialidásica revelava cálcio-dependência e relacionamento com a atividade hemolítica. A baixa taxa de hemólise exibida poderia ser explicada pela eficiente atividade sialidásica de estruturas HN sobre receptores celulares, os quais seriam essenciais para o processo de fusäo. As amostras mostravam caráteres diferentes quanto às atividades hemaglutinante e sialidásica, o que sugeriu que a seleçäo de diferentes variantes ou subpopulaçöes, uma observaçäo já feita por alguns autores, seria muito importante de ser compreendida, para um eficiente direcionamento dos processos de diagnóstico e de seleçäo de amostras virais vacinais