Characterization of an Infectivity Assay for the Ribonucleic Acid of Bacteriophage MS2

Abstract

An infectivity assay for MS2 ribonucleic acid (RNA), which uses bacterial spheroplasts of an F − strain of Escherichia coli , has an efficiency of 10 −5 infected spheroplasts per RNA molecule. The characteristics of this assay and the influence of several parameters are presented. Important variables include the duration of exposure of the cells to lysozyme-ethylenediaminetetraacetic acid, the duration of exposure of the spheroplast stock to the RNA solutions before dilution, the concentration of RNA, and the presence of competing RNA. The growth kinetics of the virus in the infected spheroplasts and the extent of lysis have also been studied.