To develop a rapid detection method for nonprotein nitrogen adulterants, this experiment sets up a set of point-scan Raman hyperspectral imaging systems to qualitatively distinguish and quantitatively and positionally analyze samples spiked with a single nonprotein nitrogen adulterant and samples spiked with a mixture of nine nonprotein nitrogen adulterants at different concentrations (5 × 10–3 to 2.000%, w/w). The results showed that for samples spiked with single nonprotein nitrogen adulterants, the number of pixels corresponding to the adulterant in the region of interest increased linearly with an increase in the analyte concentration, the average coefficient of determination (R2) was above 0.99, the minimum detection concentration of nonprotein nitrogen adulterants reached 0.010%, and the relative standard deviation (RSD) of the predicted concentration was less than 6%. For the sample spiked with a mixture of nine nonprotein nitrogen adulterants, the standard curve could be used to accurately predict the additive concentration when the additive concentration was greater than 1.200%. The detection method established in this study has good accuracy, high sensitivity, and strong stability. It provides a method for technical implementation of real-time and rapid detection of adulterants in milk powder at the port site and has good application and promotion prospects.
Summary: Adenoviral vectors (AdV) are considered promising candidates for vaccine applications. A prominent group of Toll‐like receptors (TLRs) participate in the adenovirus‐induced adaptive immune response, yet there is little information regarding the role of TLR4 in AdV‐induced immune responses in recent literature. We investigated the function of TLR4 in both adaptive and innate immune responses to an AdV‐based anthrax vaccine. By immunizing wild‐type and TLR4 knockout (TLR4‐KO) mice, we revealed the requirement of TLR4 in AdV‐induced innate responses. We also showed that TLR4 functions are required for germinal centre responses in immunized mice, as expression of the apoptosis‐related marker Fas was down‐regulated on germinal centre B cells from TLR4‐KO mice. Likewise, decreased expression of inducible costimulator on follicular T helper cells was observed in immunized TLR4‐KO mice. Moreover, a potent protective antigen‐specific humoral immune response was mimicked using an adjuvant system containing the TLR4 agonist monophosphoryl lipid A. Overall, our findings showed that very rapid antigen‐specific antibody production is correlated with the TLR4‐imprinted germinal centre response to AdV‐based vaccine. These results provide additional evidence for the use of the AdV and a TLR agonist to induce humoral responses. Our findings offer new insights into rational vaccine design.
12 July 2023 in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
The current detection method of carbendazim suffers from the disadvantages of complicated preprocessing and long cycle time. In order to solve the problem of rapid quantitative screening of finite contaminants, this article proposed a qualitative method based on characteristic peaks and a semi-quantitative method based on threshold to detect carbendazim in apple, and finally the method is evaluated by a validation system based on binary output. The results showed that the detection limit for carbendazim was 0.5 mg/kg, and the detection probability was 100% when the concentration was no less than 1 mg/kg. The semi-quantitative analysis method had a false positive rate of 0% and 5% at 0.5 mg/kg and 2.5 mg/kg, respectively. The results of method evaluation showed that when the added concentration was greater than 2.5 mg/kg, the qualitative detection method was consistent with the reference method. When the concentration was no less than 5 mg/kg, the semi-quantitative method is consistent between different labs. The semi-quantitative method proposed in this study can achieve the screening of finite contaminants in blind samples and simplify the test validation process through the detection probability model, which can meet the needs of rapid on-site detection and has a good application prospect.
2 January 2024 in Food Technology and Biotechnology
Research background. Peanut allergy poses a significant threat to human health due to the increased risk of long-term morbidity at low doses. Modifying protein structure to affect sensitization is a popular topic. Experimental approach. In this study, the purified peanut allergen Ara h 1 was enzymatically hydrolysed using Flavourzyme, alkaline protease or a combination of both. The binding ability of Ara h 1 to antibodies, gene expression and secretion levels of the proinflammatory factors interleukin-5 and interleukin-6 in Caco-2 cells was measured. Changes in the secondary and tertiary structures before and after treatment with Ara h 1 were analysed by circular dichroism and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results and conclusions. The results indicated a decrease of the allergenicity and proinflammatory ability of Ara h 1. The evaluation showed that the Flavourzyme and alkaline protease treatments caused particle shortening and aggregation. The fluorescence emission peak increased by 3.4-fold after the combined treatment with both proteases. Additionally, the secondary structure underwent changes and the hydrophobicity also increased 8.95-fold after the combined treatment. Novelty and scientific contribution. These findings partially uncover the mechanism of peanut sensitization and provide an effective theoretical basis for the development of a new method of peanut desensitization.
Peste des petits ruminants (PPR) is a serious disease that affects goats, sheep and other small ruminants. As one of the earliest and most serious countries, PPR has seriously threatened India's animal husbandry economy. In this study, the spatiotemporal characteristics of the PPR in India outbreaks were analyzed. Between 2010 and 2018, the epidemic in India broke out all over the country in a cluster distribution. Epidemic clusters in northern and southern India are at higher risk, and the outbreak time of PPR has significant seasonality. The results of the analysis of the development and transmission of PPR under the natural infection conditions showed that the PPR outbreak in India reached a peak within 15 days. Finally, the quantitative risk analysis results based on scenario tree show showed that the average probability of infecting PPRV in live sheep exported from India was 1.45 × 10–4. This study analyzed the prevalence of PPR in India. The analysis of transmission dynamics on the development of the epidemic provides a reference for the prevention and control of the epidemic. At the same time, it provides risk analysis and suggestions on trade measures for the trading countries of India.