GRA does not inactivate the rotavirus particle and inhibits replication postentry. A) RRV stocks were incubated with 25 μg/mL GRA or DMSO for one hour at 37°C. Virus then was concentrated by ultracentrifugation for two hours at 35,000 rpm in an SW55 rotor (Beckman) and infectivity was measured by IFA. Data are from triplicate samples, p < 0.001. B) Trypsin‒activated RRV was inoculated onto cells at a multiplicity of infection of 3 pfu/cell and adsorbed for one hour at 4°C. Following adsorption, the medium was replaced and cultures were incubated for one hour at 37°C to allow virus entry. 25 μg/mL GRA or DMSO was added to the culture following the 37°C incubation, and virus titers following an additional 5 hours of infection were determined by IFA. Data were analyzed for significance with the two‒tailed Student’s t test. Error bars indicate SEM. p < 0.004.