Turbidity detection of shrimp Taura Syndrome Virus by loop-mediated isothermal amplification reaction

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay is a novel method of gene amplification that amplifies nucleic acid, which can be applied for disease diagnosis in shrimp aquaculture. During the LAMP reaction, the white precipitate of magnesium pyrophosphate (Mg₂P₂O₇) is formed correlates with the amount of synthesized DNA. So, the turbidity can be measured. In this study, a portable turbidimeter has been developed for field to detection of Taura Syndrome Virus (TSV) that causes large economic losses to most major shrimp-producing countries including Thailand. The device could maintain an optimal temperature (63 °C) for 25 ¿l of LAMP sample solution contained in a 0.2 ml commercial PCR tube. We also applied the spectroscopic measurement technique to monitor a by-product of LAMP reaction, light emitting diode (LED) was used as a light source. Light dependent resistance (LDR) was used as detector. The results obtained from turbidity measurement revealed the same detection limit to those from agarose gel electrophoresis method.