Development and Interlaboratories Validation of Event-Specific Quantitative Real-Time PCR Method for Genetically Modified Rice G6H1 Event

Establishment and evaluation of a qPCR method for the detection of pfmdr1 mutations in Plasmodium falciparum, the causal agent of fatal malaria

Drug resistance surveillance is a major integral part of malaria control programs. Molecular methods play a pivotal role in drug resistance detection and related molecular research. This study aimed to develop a rapid and accurate detection method for drug resistance of Plasmodium falciparum (P. falciparum). A quantitative real-time PCR (qPCR) assay has been developed that identifies the mutation at locus A256T in the P.falciparum multi-drug resistance(pfmdr1) gene producing amino acid change at position 86. The results of 198 samples detected by qPCR were consistent with nested PCR and sequencing, giving an accuracy of 94.3%. The sensitivity, specificity, positive and negative predictive value of qPCR were 85.7%, 97.6%, 90.0% and 96.4%, respectively. The results of qPCR are basically consistent with the nested PCR, which is expected to replace the nested PCR as a new molecular biological method for drug resistance detection, providing reliable technical support for global malaria prevention and control.

A label-free electrochemical impedimetric DNA biosensor for genetically modified soybean detection based on gold carbon dots

A label-free electrochemical impedimetric biosensor was constructed based on gold carbon dots (GCDs) modified screen-printed carbon electrode for the detection of genetic modified (GM) soybean. The structure and property of GCDs were investigated. The GCDs can directly bind to single-stranded DNA probes through Au-thiol interaction and boost electric conductivity for the DNA sensor construction. The quantification of target DNA was monitored by the change of electron-transfer resistance (Ret) upon the DNA hybridization on sensor surface. Under the optimal conditions, the Ret response (vs. Ag reference electrode) increased with the logarithm of target DNA concentrations in a wide linear range of 1.0 × 10-7 - 1.0 × 10-13 M with a detection limit of 3.1 × 10-14 M (S/N = 3). It was also demonstrated that the proposed DNA sensor possessed high specificity for discriminating target DNA from mismatched sequences. Moreover, the developed biosensor was applied to detect SHZD32-1 in actual samples, and the results showed a good consistency with those obtained from the gel electrophoresis method. Compared with the previous reports for DNA detection, the label-free biosensor showed a comparatively simple platform due to elimination of complicated DNA labeling. Therefore, the proposed method showed great potential to be an alternative device for simple, sensitive, specific, and portable DNA sensor.

Development and evaluation of a novel loop mediated isothermal amplification coupled with TaqMan probe assay for detection of genetically modified organism with NOS terminator

In this study, we aim to develop a novel loop mediated isothermal amplification (LAMP) coupled with TaqMan (LAMP-TaqMan) method for quick qualitative detection of genetically modified organism (GMOs). We designed four LAMP primers and one TaqMan probe for the LAMP-TaqMan detection method to detect the nopaline synthase gene (NOS) terminator in GMOs. This assay enabled the amplification of DNA within ~20 min at a constant temperature of 65 °C. This assay detected as few as five copies of target sequences, which had a high specificity similar to the TaqMan qPCR method. Furthermore, the LAMP-TaqMan detection method was successfully used to amplify and detect DNA from food samples of the major crops (soybean, maize, rice, etc.). In summary, a novel LAMP-TaqMan assay has been developed, which has the similar sensitivity but takes less time than the TaqMan qPCR method. This method offers a novel approach for rapid detection of GMOs in foods.

Identification of the Pol Gene as a Species-Specific Diagnostic Marker for Qualitative and Quantitative PCR Detection of Tricholoma matsutake

Tricholoma matsutake is a rare, precious, and wild edible fungus that could not be cultivated artificially until now. This situation has given way to the introduction of fake T. matsutake commodities to the mushroom market. Among the methods used to detect food adulteration, amplification of species-specific diagnostic marker is particularly important and accurate. In this study, the Pol gene is reported as a species-specific diagnostic marker to identify three T. matsutake varieties and 10 other types of edible mushrooms through qualitative and quantitative PCR. The PCR results did not reveal variations in the amplified region, and the detection limits of qualitative and quantitative PCR were found to be 8 ng and 32 pg, respectively. Southern blot showed that the Pol gene exists as a single copy in the T. matsutake genome. The method that produced the purest DNA of T. matsutake in this study was also determined, and the high-concentration salt precipitation method was confirmed to be the most suitable among the methods tested. The assay proposed in this work is applicable not only to the detection of raw materials but also to the examination of processed products containing T. matsutake.