[Selection of heparin-sensitive dengue virus variants in BHK-21 cells].

Several studies have shown that adaptation of various viruses to grow in certain cell lines of vertebrates, leads to the selection of virus variants that bind heparan sulfate (HS) with high affinity. In this study we investigated the susceptibility of strains of dengue virus (DENV) to oversulfated heparin an analogue of HS after passages in BHK-21 cells. Field isolates of the four serotypes of DENV with a limited number of passes in mosquito cells C6/36HT were serially passaged eight times in BHK-21 cells.

Evolution of dengue virus type 3 genotype III in Venezuela: diversification, rates and population dynamics.

Background: Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV are comprised of four distinct serotypes (DENV-1 through DENV-4) and each serotype can be divided in different genotypes. Currently, there is a dramatic emergence of DENV-3 genotype III in Latin America.

Characterization of neuraminidase-resistant mutants derived from rotavirus porcine strain OSU.

Infection by some rotavirus strains requires the presence of sialic acid on the cell surface, its infectivity being reduced in cells treated with neuraminidase. A neuraminidase treatment-resistant mutant was isolated from the porcine rotavirus strain OSU. In reassortant strains, the neuraminidase-resistant phenotype segregated with the gene coding for VP4.

Mutation analysis of the HFE gene associated with hereditary hemochromatosis in a Venezuelan sample.

The frequency of the C282Y, H63D and S65C alleles of the HFE gene was determined in a sample of the Venezuelan population. Two new sets of primers were tested for amplifying the regions mapping these mutations, and genotyping was performed by restriction fragment length polymorphism (RFLP). DNA sequencing was used to validate the RFLP analysis.

A novel type of VP4 carried by a porcine rotavirus strain.

The gene encoding the VP8* trypsin-cleavage product of the VP4 protein of porcine rotavirus strain A34 was sequenced, and the predicted amino acid (aa) sequence was compared to the homologous region of all known P genotypes. The aa sequence of the VP8* of strain A34 shared low identity, ranging from 39% (bovine strain B223, P8[11]) to 76% (human strain 69M, P4[10]), with the homologous sequences of representative strains of the remaining 21 P genotypes. Phylogenetic relationships showed that the VP8* of strain A34 shares a common evolutionary lineage with those of human 69M (P4[10]) and equine H-2 (P4[12]) strains.