Detection of murine norovirus 1 by using plaque assay, transfection assay, and real-time reverse transcription-PCR before and after heat exposure

Abstract

The correlation between the detection of murine norovirus 1 RNA by real-time reverse transcription-PCR and the infectivity by plaque assay before and after heat exposure (80 degrees C) was examined. No correlation was found in the current study. Moreover, heat inactivation had a much stronger detrimental effect on virus infectivity than on the integrity of the viral genome.

FIG. 1.

Inactivation profile of MNV-1 exposed to 80°C (×, solid line), shown as log₁₀ PFU/ml versus time (in seconds). The temperature profile (▵, dashed line) is shown as temperature (°C) versus time (in seconds). Experiments were done in duplicate. Error bars, standard deviations (Microsoft Excel, version 2003).

FIG. 2.

Standard curve of MNV-1 real-time PCR directed to the ORF1/ORF2 junction region. The cycle threshold (C_T) is plotted against the log₁₀ copy number of the plasmid containing a full-length copy of the MNV-1 genome. Error bars, standard errors of the means (SPSS 12.0 for Windows [SPSS Inc.]) from 10 independent runs.