Detection of meat from horse, donkey and their hybrids (mule/hinny) by duplex real-time fluorescent PCR.

Meat adulteration is currently a common practice worldwide. In China, adulteration of donkey meat products with the similar species (horse and mule/hinny) meat and mislabeling are becoming widespread concerns. In this study, a sensitive and species-specific duplex real-time PCR assay based on the simultaneous amplification of fragments of the creatine kinase muscle gene family, was developed and optimized for the identification of horse, donkey and mule /hinny species in raw and heat-processed meat products. Duplex real-time PCR results showed different fluorescence amplification curves for horse and donkey. Both kinds of fluorescence amplification curves appeared simultaneously for mule/hinny. The limit of detection (LOD) of the method was up to 0.01 ng /µL. The method and strategy developed in this study could be applied to detect the presence of adulterants from horse and mule /hinny meat in raw donkey meat and meat products.

WS2 quantum dots-MnO2 nanosheet system for use in ratiometric fluorometric/scattered light detection of glutathione.

Based on WS2 quantum dots (QDs) as fluorescent signals and MnO2 nanosheets as second-order scattering (SOS) signals, a combination of fluorescence and scattered light was used to construct a ratio sensing platform for glutathione (GSH) detection. When MnO2 nanosheets are added to WS2 QDs, the fluorescence of WS2 QDs is quenched by MnO2 nanosheets through IFE. Large-sized MnO2 nanosheets increase the SOS of the system and gradually approach the fluorescence. After adding GSH to WS2 QDs-MnO2, the MnO2 nanosheets were decomposed into Mn2+. The disappearance of the characteristic absorption peak of the MnO2 nanosheets suppressed the IFE to WS2 QDs, resulting in the fluorescence recovery of WS2 QDs. The reduction in size of MnO2 nanosheets after decomposition results in a decrease in the SOS of the system. Therefore, the ratio detection of GSH is obtained through the fluorescence and SOS dual signal response. Under optimal experimental conditions, the value of F406/S648 is linearly related to the GSH concentration in the range 0 to 60 µM, and the limit of detection (LOD) of GSH is 0.12 µM. In addition, the system is also used for the determination of GSH in real water samples and human serum, with good analytical results. Graphical abstract Schematic principle of fluorescence/scattered light system based on WS2 QDs-MnO2 for GSH ratiometric detection.

Response of anodic biofilm and the performance of microbial fuel cells to different discharging current densities.

To better understand the responses of anodic biofilm and MFC performance, five identical MFCs started at 100Ω were operated with different discharging current densities (0.3, 1.6, 3.0, 3.6 and 4.8A/m2, denoted as MFC-0.3, MFC-1.6, MFC-3.0, MFC-3.6 and MFC-4.8, respectively). It was demonstrated that the discharging current would significantly influence biofilm development and MFC performance. Compared with the original MFC started at 100Ω, the performance of MFC-0.3 and MFC-1.6 decreased, whereas MFC-3.0 and MFC-3.6 exhibited improved maximum power densities. This was attributed to the reduced charge transfer resistance resulting from the increased active biomass after increasing discharging current. This indicated that the increasing discharging current could enhance active biomass and performance. However, a high discharging current density (4.8A/m2) caused the exfoliation of carbon particles from the carbon cloth and then the detachment of the anode biofilm, resulting in the cell failure of MFC-4.8.