Because there are so many virus particles excreted in the stool of an infected infant it is possible to extract rotavirus dsRNA in sufficient quantities for PAGE. The migration patterns of the 11 dsRNA segments allow rotaviruses to be typed. There are three major electropherotypes: long, short, and super-short. With the short electropherotype, the 11th genomic segment is larger than usual and thus migrates more slowly resolving between the 9th and 10th segments. With the super-short electropherotype, the 11th segment is even larger. By using radiolabeled, positive sense single-stranded RNA transcribed from viral cores in Northern blots at high stringency, it is possible to subdivide group A rotaviruses into two major genogroups. These are named for the prototype strains, namely, Wa (genogroup 1) and DS-1 (genogroup 2). The Wa genogroup viruses are generally long electropherotype, subgroup II with VP4 P or P and VP7 G1, G3, or G4 genotypes, whereas the DS-1 genogroup are usually subgroup I, short electropherotype, and P and G2 genogroup. However, these broad subdivisions are being eroded by the tremendous variability of rotaviruses infecting man and other animals.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.