Physiochemical characterization of a neonatal calf diarrhea virus

Physicochemical characteristics of two isolates of a neonatal calf diarrhea virus were investigated. Neither isolate was sensitive to ether or chloroform, both were stable at pH 3.0, were relatively heat resistant, but were thermolabile when heated to 50 degrees C for one hour in the presence of 1.0 M MgCl(2). Multiplication of virus was not inhibited by concentrations of 5-iodo-2'-deoxyuridine (IDUR) up to 500 microg/ml, which indicated that the nucleic acid was ribonucleic acid (RNA). Also, multiplication was not inhibited by concentrations of actinomycin D (AD) up to 0.5 microg/ml. Thermal denaturation studies demonstrated that the nucleic acid had a high melting temperature. Resistance to lipid solvents, stability at an acid pH, relatively high thermostability, type of nucleic acid, plus previous reports from this laboratory on general morphology and cytopathogenicity suggest that the virus may belong to the diplornavirus (reovirus) group. However, thermolability in the presence of 1.0 M MgCl(2) is not consistent with characteristics of this group.