A reliable and sensitive time-resolved fluorescent immunochromatographic assay (TRFICA) for ochratoxin A in agro-products

Immunochromatographic assays (ICAs) are considered as a suitable diagnostic tool for the detection of mycotoxins. Mycotoxins and especially, ochratoxin A are analytes with more demanding sensitivity requirements. To enhance the sensitivity of current immunochromatographic assays for ochratoxin A (OTA), a novel sensitive ICA was developed in this study. In the assay, microspheres enclosing fluorescent europium (III) [Eu(III)] nanoparticles (EuNPs) were used as a label for OTA monoclonal antibody (OTA-mAb) conjugation. Accordingly, assay was called time-resolved fluorescent immunochromatographic assay (TRFICA). The test strip was composed of three parts: a sample pad, nitrocellulose membrane and an absorbent pad. As for detection, a proper concentration of conjugated microspheres was pipetted into the microtube and sample extract was added to it. Then the strip was inserted into the tube and the fluid flow along the strip. The TRFICA results were obtained in 8 min and read by a portable TRFICA strip reader. The established method allows quantitative determination of OTA with limit of detection as low as 1.0 μg kg⁻¹ in the samples. For validation, spiked samples including wheat, maize, soybean and rice were respectively assayed by TRFICA and a standard high performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD), and good agreement of results was obtained between two methods.     

Rapid detection method for aflatoxin B1 in soybean sauce based on fluorescent microspheres probe

Soybean sauce, a Chinese traditional and daily condiment, is often contaminated by aflatoxin B₁. An extract-free immunochromatographic assay was proposed based on fluorescent microspheres probe for the' detection of aflatoxin B₁ in soybean sauce. The probe was prepared by coupling fluorescent microspheres with anti-aflatoxin B₁ antibody by the 1-ethyl-3(3-dimethylaminopropyl) carbodiimides hydrochloride-mediated method. The background from the soybean sauce sample on strip was eliminated because of the optical property of the probe. The sample without extracting procedure was directly detected by diluting with 10% methanol solution. The visible detection limit for the qualitative analysis of aflatoxin B₁ in the proposed method was 2.5 μg/L, which was lower than the maximum level of 5 μg/L set by the Chinese government. The results were well agreed with those obtained by liquid chromatography-mass spectrometry (LC-MS). The method showed satisfactory characteristics, such as rapid detection, easy operation, and high sensitivity, and can thus be applied for the large-scale and on-site screening of soybean sauce contaminated with aflatoxin B₁. To our knowledge, this report is the first one on the qualitative detection of aflatoxin B₁ in dark colored food samples directly by fluorescent microspheres probe-based immunochromatography.     

Efficacy of the theory of planned behaviour model in predicting safe food handling practices

The majority of food-borne disease outbreaks result from malpractice during food preparation in small food businesses. Effective food safety management, including the adoption of safe food handling practices learnt during food safety training programmes, is thus an important strategy to limit incidences of food poisoning. This study explores the impact of basic or foundation level food hygiene training on the attitudes, and intentions of food handlers to conduct safe food handling practices at every occasion.The Theory of Planned Behaviour was used to evaluate the relative impact of different influences on the intentions and self-reported behaviours of 249 food handlers, in hospitality settings. Interviews were also conducted with food handlers, and their managers to seek further insight into the changes in attitude and intent to conduct safe food handling practices after basic or foundation level food hygiene training.     

人参茸芝胶囊的急性毒性实验研究

目的研究人参茸芝胶囊的急性毒性,评价人参茸芝胶囊的安全性。方法根据中药、天然药物急性毒性实验技术指导原则,将60只小鼠按体质量随机分为给药组和空白对照组,禁食不禁水12 h后,给药组将人参茸芝胶囊以最大浓度(2.2 g·m L-1),最大体积(40 m L·kg-1)灌胃给药,空白对照组以等容积的蒸馏水灌胃给药,连续14 d观察小鼠体质量、行为活动以及死亡情况。14 d后处死所有小鼠,观察小鼠心、肝、肾、脑等脏器是否正常。结果给药组小鼠无1例死亡,与对照组比较,给药组小鼠的体质量变化和进食量无显著差异,行为活动无异常。尸解后未见给药组小鼠的脏器异常。小鼠的人参茸芝胶囊的半数致死量(LD50)未测得,最大耐受量(MTD)为88 g·kg-1。结论从药物急性毒性研究结果来看,人参茸芝胶囊是一个安全的剂型。     

The wildspace™ decision support system

A system architecture was developed for the wildspace decision support system (DSS) to provide a better understanding of complex wildlife and habitat problems. The system makes use of two key concepts, SPECIES and SPACES, to define the study domain. wildspace DSS’s flexible user interface allows users to select SPECIES through a number of different approaches, including direct selection and selection using information such as avian life history and project metadata. On the SPACES side, the system uses the raison™ object system (ROS) for mapping functions and spatial analysis. The key element in wildspace DSS is its knowledge-based database manager that provides intelligent support to various components of the system. It keeps track of all the legitimate databases, provides intelligence within the SPECIES and SPACES selection process and, more importantly, interfaces with the knowledge templates which are sets of operations implementing pre-defined analysis routines used for integrated analysis. This integrated decision support approach allows users to combine a diverse set of tools within a common framework. wildspace DSS is used to study complex wildlife problems involving multiple projects and data that are temporally and spatially heterogeneous. A case study about a relevant wildlife conservation question is presented using a series of queries and analyses performed within wildspace DSS. The system also serves as the repository for all past, current and future wildlife data collected by the Canadian Wildlife Service—Ontario Region.     

Novel monoclonal antibody-based sensitive enzyme-linked immunosorbent assay and rapid immunochromatographic strip for detecting aflatoxin M1 in milk

Monoclonal antibody (mAb) that is specific to AFM1 was generated from the hybridoma cell line, 10F3C10, which was obtained by the fusion of mouse NS1 myeloma cells with the spleen cells of mouse that had been immunized with AFM1-bovine serum albumin (BSA). The 10F3C10 mAb is belong to the immunoglobulin G1 isotype. Both competitive direct and indirect enzyme-linked immunosorbent assay (ELISA) was utilized to characterize the mAb for AFM1. The concentrations of AFM1, AFB1 and AFG1 that caused 50% inhibition (IC₅₀) of the binding of AFM1-horseradish peroxidase (AFM1-HRP) to the antibody were found to be 0.022, 0.310 and 2.12 ng/mL, respectively. The immunochromatographic strip (immunostrip) assay with mAb-gold nanoparticle conjugates as a detection marker exhibited a visual limit of detection of 0.1 ng/mL for AFM1 and the analysis took a total of 10 min. Closely examining 17 milk-based samples using cdELISA revealed that four were slightly contaminated with AFM1 at concentrations from 0.002 to 0.054 ng/mL. All milk samples were negative in the immunostrip test because the levels of contaminant were below the detection limit of the strip. Notably, the presented cdELISA and immunostrip methods are highly sensitive methods for detecting AFM1 in milk.     

短梗五加果多酚提取工艺优化及抗疲劳作用

目的：短梗五加果多酚的提取工艺及抗疲劳作用探讨。方法：通过正交试验考察提取次数、提取时间及液料比对短梗五加果多酚得率的影响;建立小鼠负重游泳疲劳模型,考察短梗五加果多酚的抗疲劳作用。结果：短梗五加果多酚提取的因素影响次序为：提取时间＞液料比＞提取次数,正交试验结果表明最佳提取工艺条件为液料比20∶1（mL/g）、提取时间60?min、提取2?次,短梗五加果多酚得率为1.426%;体内研究结果表明短梗五加果多酚能显著延长小鼠负重游泳力竭时间,显著增加机体肝糖原、肌糖原含量,明显提高小鼠体内谷胱甘肽过氧化物酶活力,同时降低乳酸和肌酸激酶水平。结论：短梗五加果多酚能提高小鼠抗疲劳能力。     

灵芝水溶性蛋白提取工艺优化

目的优化破壁灵芝孢子粉及灵芝子实体中水溶性蛋白的提取工艺。方法采用中心组合设计方法,以提取温度、提取时间、固液比为考察因素,研究各因素及其交互作用对水溶性蛋白提取率的影响。应用SAS软件和响应面分析相结合的方法,模拟得到回归方程的预测模型和可信度,并通过岭脊分析得到最佳提取条件。结果破壁灵芝孢子粉中水溶性蛋白最佳的提取条件为:提取温度92℃、提取时间196 min、固液比1:173。而灵芝子实体的最佳提取工艺为:提取温度94℃、提取时间157 min、固液比1:166。结论最佳条件下孢子粉中水溶性蛋白的提取率为1.57%,而子实体中水溶性蛋白的提取率为0.96%。     

Microstructures and electrochemical performances of La2Mg(Ni0.85Co0.15)9Crx (x = 0–0.2) electrode alloys prepared by casting and rapid quenching

In order to improve the electrochemical cycle stability of La–Mg–Ni system (PuNi₃-type) hydrogen storage alloy, a trace of Cr was added and rapid quenching techniques were employed. The electrochemical performances and microstructures of the as-cast and -quenched alloys were determined and measured. The effects of Cr content and quenching rate on the microstructures and electrochemical properties of the alloys were investigated in detail. The obtained results show that the as-cast and -quenched alloys are composed of the (La, Mg)Ni₃ phase (PuNi₃-type structure) and the LaNi₅ phase as well as the LaNi₂ phase. The amount of the LaNi₂ phase increases with the increase of Cr content. The addition of Cr enhances the cycle stability of the as-cast and -quenched alloys, but decreases the discharge capacities of the alloys. The cycle lives of the alloys increase with the increase of the quenching rate. The as-cast and -quenched alloys have an excellent activation performance.