Detection of Pyricularia oryzae Based on Indirect ELISA Using Germinating Conidia as the Antigen Preparation

Abstract

One of the most destructive fungal diseases in rice crop in Malaysia is the Rice blast disease or Penyakit Karah, which is caused by Pyricularia oryzae Cav. (previously known as Magnoporthe grisea). The disease can cause a loss of yield of more than 50 percent. In this study a sensitive indirect ELISA method was developed for the detection of Pyricularia oryzae through an indirect ELISA method using rabbit polyclonal antibody against different concentrations of Pyricularia oryzae conidia to give seven calibration standard points ranging from 1×101 to 1×109 conidia/mL. The calibration curve shows a typical sigmoidal curve and the fitting of the curve was based on the four-parameter logistic equation. The calculated LOD value was 21.60 conidia/mL (95% confidence interval, 11.63 to 31.57 conidia/mL) with a good correlation coefficient value of 0.999 indicating the model fit the experimental data in an excellent manner. The sensitivity was comparable to another published work which claimed to be the most sensitive to date. This indicate that the current developed method can be utilized in the future as a sensitive method for the rapid and simple detection of this pathogen.

Detection of cancer‐associated miRNA using a fluorescence switch of AgNC@NA and guanine‐rich overhang sequences

“…I MAX and I B are fluorescence intensity values at the top and at the bottom of the curve, respectively, EC50% is the fluorescence intensity value that produces a 50% signal response, and the Hill coefficient, HC, is the slope-like parameter. [42,43] The LOD was then calculated strategy for the detection of miR sequences and tested it on miR371a-3p, which can serve as a biomarker in testicular cancer. We envision, in the future, the construction of more effective and optimized switch assemblies suitable for diagnostic applications.…”

“…The sigmoidal dependence of the binding kinetics described by the signal intensity versus analyte concentration could be statistically analyzed using the four-parameter logistic (4PL) curve for calculating the analytical limit of detection (LOD) of the method. [42,43] As we did not know the exact binding model in this three-substrate assembly process, 4PL was used to obtain the characteristic parameters for the performance of the AgNC@DNA + G 15 switch:…”