Development of TaqMan probe-based insulated isothermal PCR (iiPCR) for sensitive and specific on-site pathogen detection

PLoS One. 2012;7(9):e45278. doi: 10.1371/journal.pone.0045278. Epub 2012 Sep 25.

Abstract

Insulated isothermal PCR (iiPCR), established on the basis of Ralyeigh-Bénard convection, is a rapid and low-cost platform for nucleic acid amplification. However, the method used for signal detection, namely gel electrophoresis, has limited the application of iiPCR. In this study, TaqMan probe-based iiPCR system was developed to obviate the need of post-amplification processing. This system includes an optical detection module, which was designed and integrated into the iiPCR device to detect fluorescent signals generated by the probe. TaqMan probe-iiPCR assays targeting white spot syndrome virus (WSSV) and infectious myonecrosis virus were developed for preliminary evaluation of this system. Significant elevation of fluorescent signals was detected consistently among positive iiPCR reactions in both assays, correlating with amplicon detection by gel electrophoresis analysis. After condition optimization, a threshold value of S/N (fluorescent intensity(after)/fluorescent intensity(before)) for positive reactions was defined for WSSV TaqMan probe-iiPCR on the basis of 20 blank reactions. WSSV TaqMan probe-iiPCR generated positive S/Ns from as low as 10(1) copies of standard DNA and lightly infected Litopenaeus vannamei. Compared with an OIE-certified nested PCR, WSSV TaqMan probe-iiPCR showed a sensitivity of 100% and a specificity of 96.67% in 120 WSSV-free or lightly infected shrimp samples. Generating positive signals specifically and sensitively, TaqMan probe-iiPCR system has a potential as a low-cost and rapid on-site diagnostics method.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA Primers / genetics
  • Nucleic Acid Denaturation
  • Penaeidae / virology*
  • Polymerase Chain Reaction / instrumentation
  • Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • Temperature
  • Totiviridae / genetics*
  • Totiviridae / isolation & purification*
  • White spot syndrome virus 1 / genetics*
  • White spot syndrome virus 1 / isolation & purification*

Substances

  • DNA Primers

Grants and funding

This study was supported by the Taiwan National Science Council (NSC) grant NSC 99-2112-M-005-006-MY3 to CCJ, and NSC-Central Taiwan Science Park grant NSC-CTSP 302403501 to GeneReach Biotechnology Corporation (http://web1.nsc.gov.tw/mp.aspx?mp=1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.