Figure 3

Detection of MERS-CoV RNA from tissue culture-derived virions through reverse transcription and LAMP amplification (RT-LAMP).
(A) Agarose gel electrophoretic characterization of RT-LAMP amplicons from samples containing RNA extracted from 60 PFU of MERS-CoV virons (or 2 μL 3E4 PFU/mL) (P-3) or samples lacking MERS-CoV RNA (N-1 and N-2). For each sample, the LAMP reaction was carried out at 55 oC for 1.5 hours and developed on a 1% agarose gel stained with ethidium bromide. (B) Glucometer responses for amplification reactions with RNAs extracted from 0.06 (P-1), 0.6 (P-2), 60 (P-3 and P-4) PFU MERS-CoV virions (2 μL) and with RNA-negative samples (N-1, N-2 and N-3). Samples underwent 1.5 hour or 10 min 55 oC RT-LAMP reactions, 1 hour 25 oC OSD and 23 min 55 oC glucose generation with thermostable TmINV. The signals shown in N-1, N-2 and P-3 in Fig 3B were obtained from the same RT-LAMP reactions as the N-1, N-2 and P-3 samples shown in Fig 3A. It should be noted that the LAMP reaction for sample N-2 produces non-specific amplicons but these do not produce a false positive glucometer signal. The error bars represent standard deviations calculated from three parallel assays.