One of the distinguishing features of the alphaviruses is a sequential processing of the nonstructural polyproteins P1234 and P123. In the early stages of the infection, the complex of P123+nsP4 forms the primary replication complexes (RCs) that function in negative-strand RNA synthesis. The following processing steps make nsP1+P23+nsP4, and later nsP1+nsP2+nsP3+nsP4. The latter mature complex ...

Temperature-sensitive (ts) mutants of Sindbis virus belonging to complementation group F, ts6, ts110, and ts118, are defective in RNA synthesis at the nonpermissive temperature. cDNA clones of these group F mutants, as well as of ts+ revertants, have been constructed. To assign the ts phenotype to a specific region in the viral genome, restriction fragments from the mutant cDNA clones were used...

Rotaviruses are the major etiological agents of diarrhea in children less than 5 years of age. Two unusual rotavirus strains not previously reported in India, G11P[25] (CRI 10795) and G3P[3] (CRI 33594) were isolated from faecal samples of asymptomatic children in India. The strains were characterized by sequence analysis of the genes encoding the VP7, VP4, VP6, and NSP4. The G11P[25] strain wa...

A porcine group A rotavirus (GARV) strain, 61/07/Ire, was isolated from a 4-5 week asymptomatic piglet, during an epidemiological survey of porcine herds in Southern Ireland, in 2007. The nucleotide (nt) and amino acid (aa) sequence of the full-length VP4 protein of the PoRV strain 61/07/Ire was determined. Based on the entire VP4 open reading frame (nt), strain 61/07/Ire displayed ≤76.5% ident...

Semliki Forest virus (SFV) is an arthropod-borne alphavirus that induces membrane invaginations (spherules) in host cells. These harbor the viral replication complexes (RC) that synthesize viral RNA. Alphaviruses have four replicase or nonstructural proteins (nsPs), nsP1-4, expressed as polyprotein P1234. An early RC, which synthesizes minus-strand RNA, is formed by the polyprotein P123 and the...

A human rotavirus strain (NB-150) was detected in stool samples from a neonate hospitalized for mild/moderate community-acquired diarrhoea. This baby lived in the outskirts of Belém, Brazil, under poor sanitation conditions. The NB-150 strain displayed a typical long electrophoretic pattern with 11 gene segments. It had two VP7 alleles, G1 and G4, and belonged to VP6 subgroup II. A close relate...