一种5 重real-time PCR筛查转基因水稻方法的建立

以转基因水稻中最常用的CaMV35S启动子、NOS终止子、Cry1Ab/Ac基因、HPT基因及SPS水稻内标基因为研究对象，利用5 种不同的荧光信号（FAM、HEX、Taxas Red、Cy5、Cy5.5）进行多重实时聚合酶链式反应（real-time polymerase chain reaction，real-time PCR）检测方法的研究。通过引物组合筛选、反应体系优化、特异性测试、灵敏度测试、适用性测试等一系列实验，建立了5 重real-time PCR方法，灵敏度可达0.032%。此方法具有灵敏度高、结果准确、通量大等优点，可实现水稻中转基因成分的快速、高效检测。     

Synergetic effects of high-pressure carbon dioxide and nisin on the inactivation of Escherichia coli and Staphylococcus aureus

Synergetic effects of high-pressure carbon dioxide (HPCD) and nisin on Escherichia coli and Staphylococcus aureus were evaluated. Changes in morphology, interior structure, and membrane permeability were analyzed by scanning and transmission electron microscopy, and flow cytometry. Synergetic effects were found, especially in S. aureus. HPCD alone or with nisin led to morphological and intracellular alterations in both bacteria, but nisin alone led to these damages only in S. aureus. A positive correlation between membrane damage and inactivation was found, but ratios of inactivation were higher, probably because of viable but non-culturable state. Mechanisms were proposed for synergism: for E. coli, outer membrane was damaged first by HPCD, and then HPCD and nisin jointly acted on and destroyed the cytoplasmic membrane, leading to further intracellular damage by HPCD; for S. aureus, HPCD and nisin acted on the cytoplasmic membrane together leading to cell death.Industrial RelevanceEscherichia coli and Staphylococcus aureus are two common microorganisms, which exist widely in the environment and easily contaminate food such as vegetables and dairy products, respectively. Considering heat treatment may destroy some heat-sensitive quality of the products, this study evaluated synergetic effects of high-pressure carbon dioxide (HPCD) combined with the bacteriocin nisin. The investigations provided evidence for potentially combined application of HPCD and nisin to help keep food safe in the industry.     

微生物源单宁酶的研究进展

单宁酶可将单宁水解成没食子酸和葡萄糖，是一种重要的工业用酶。植物、动物和微生物中都含单宁酶，其中微生物是单宁酶的主要来源。基于单宁酶的国内外研究成果，该文归纳总结了不同微生物来源的单宁酶、酶学性质、作用机制，阐述了单宁酶在食品、饲料、制革、精细化工等实际生产中的应用，并对单宁酶今后的研究方向和应用前景进行了展望。     

Graphene oxide–tripolyphosphate hybrid used as a potent sorbent for cationic dyes

Graphene oxide–tripolyphosphate material (GPM) was synthesized through an ethanolamine (EA) mediated graphene oxide (GO) self-assembly. The synthesis route to GPM is simple and benign. GPM was composed of GO nanosheets as building blocks and the tripolyphosphate as cross-linkers and chelators of cations in solutions. GPM showed higher potency for adsorption of cationic dyes than anionic dyes, and the adsorption process was through electrostatic and π–π interactions. Adsorption was spontaneous and exothermic, and the adsorption capacity of GPM for cationic dyes (>2540 mg g⁻¹) far exceeded those reported in literature for GO materials.     

Chlorpyrifos residue levels on field crops (rice,maize and soybean) in China and their dietary risks to consumers

In this study, chlorpyrifos residue levels in field crops of rice, maize and soybean were investigated according to the “Guideline on Pesticide Residue Trials” of China. On the basis of the residual results, human dietary risks were further evaluated. Chlorpyrifos residues of harvest grains were firstly prepared by QuEChERS method and analyzed using Gas Chromatography Tandem Mass Spectrometry (GC–MS/MS). Dietary risks were assessed by a deterministic approach. The median residues in field trials of rice, maize and soybean were 0.617, 0.0227 and 0.0136 mg kg⁻¹, respectively. The highest residues in field trials of rice, maize and soybean were 3.23, 0.114 and 0.102 mg kg⁻¹, respectively. Chronic intake assessment indicated that only 39.0% of acceptable daily intake (ADI, 0–0.01 mg kg bw⁻¹ day⁻¹) was consumed through rice, maize and soybean. The acute hazard indexes (aHI) of adults was 26.1% of acute reference dose (ARfD, 0–0.1 mg kg bw⁻¹) and aHI of children was 63.5% of ARfD in dietary exposure assessment through rice, maize and soybean consumption. Single pathway risk assessment indicated that chlorpyrifos application on field crops in manner of the good agricultural practices didn't pose public health risks.     

固相萃取-高效液相色谱法测定草莓中氟唑菌酰胺残留量

[目的]建立草莓中氟唑菌酰胺残留量的测定方法。[方法]采用乙腈提取,氨基固相萃取柱净化,高效液相色谱法测定。[结果]添加氟唑菌酰胺水平为0.05、0.1、0.5mg/kg,平均回收率分别为83.5%、89.6%和90.4%,相对标准偏差分别为7.1%、4.9%和2.0%,检出限为0.05 mg/kg。[结论]方法操作简单,定量准确,重现性好。     

超高效液相色谱-串联质谱法检测花生中18种塑化剂的研究

为了解决塑化剂检测的问题,本文建立了高效液相色谱-串联质谱法检测花生中18种塑化剂。样品经乙腈超声提取并低温低速离心后,直接取上清液置于-18℃冰箱中冷冻至少2 h,上清液过膜后经Shim-pack XR-ODS Ш 反相色谱柱(150 mm×2.0 I.D., 2.0 μm)分离,最后用三重四极杆质谱在多反应监测模式下外标法定量测定。在最佳分析条件下,各塑化剂靶标线性范围均良好,相关系数(r2)均>0.999;检出限和定量限分别在0.0004~1.0000μg/kg和0.0012~3.0000 μg/kg范围内;在3个不同浓度下的加标回收率位于75.26%~114.54%之间,相对标准偏差为1.08%~8.00% (n=6)。该方法操作简单、稳定可靠、检测通量高、检测成本低,有望用于大批量花生样品中塑化剂质量安全风险评估筛查及验证分析,为政府部门粮油质量安全监管提供技术支撑。     

A TLC-HPLC Method for Determination of Thiamphenicol in Pig,Chicken, and Fish Feedstuffs

An effective thin-layer chromatography (TLC) purification procedure coupled to high-performance liquid chromatography (HPLC) method was developed for the determination of thiamphenicol (TAP) in pig, chicken, and fish feedstuffs. The feedstuff samples were extracted with ethyl acetate, defatted with n-hexane saturated with acetonitrile, and further purified by TLC. The chromatographic separation was performed on a Waters Symmetry C₁₈ column using an isocratic procedure with acetonitrile-water (21.7:78.3, v/v) at 0.6 mL/min. The ultraviolet (UV) detector was set at a wavelength of 225 nm. The TAP concentrations in feedstuff samples were quantified using a standard curve. Good linear correlations (y?=?162,630x???2381.7, r?>?0.9998) were achieved within the concentration range of 0.05–10.00 μg/mL. The recoveries of TAP spiked at levels of 1, 10, and 100 μg/g ranged from 82.0 to 114.9% with the intra-day and inter-day relative standard deviation (RSD) less than 9.0%. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.02 and 0.03 mg/kg for pig feedstuffs, 0.02 and 0.04 mg/kg for chicken feedstuffs, and 0.02 and 0.03 mg/kg for fish feedstuffs, respectively. This reliable, simple, and cost-effective method could be applied to the routine monitoring of TAP in animal feedstuffs.     

乙型副伤寒沙门氏菌在鲜切黄瓜中的生长行为及预测模型建立

为建立不同温度条件下鲜切黄瓜中乙型副伤寒沙门氏菌的生长预测模型,将新鲜黄瓜切丁,添加乙型副伤寒沙门氏菌,分别在10、15、20、25、30和35℃下的恒温条件下贮藏,以观察细菌的生长。使用USDA综合病原体建模程序(USDA-IPMP)拟合每个温度下每种细菌的生长曲线,以找出描述该细菌生长的最适初级生长模型,并拟合得到最大比生长速率。通过温度对初级模型中最大比生长速率的生长动力学拟合,分别建立Ratkowsky、Huang rate、Cardinal、Arrhenius-type二级生长模型,并进行数学评估和实测样品验证。结果表明,实验数据和生长曲线显示乙型副伤寒沙门氏菌的生长表现出三个阶段,包括延滞期,指数期和稳定期。乙型副伤寒沙门氏菌的延滞期时间随着孵育时间的增加而降低。相反,乙型副伤寒沙门氏菌的生长速率随着孵育温度而增加,由此表明风险随温度的升高而增加。使用Baranyi和Huang初级模型分析两种病原体的生长曲线,使用Ratkowsky、Huang平方根模型、Cardinal和Arrhenius模型描述温度对贮藏时间细菌生长的影响,同时应用实验数据和样品实测验证评估所建立的预测模型。从该研究中获得的结果和预测模型可用于预测鲜切黄瓜产品中乙型副伤寒沙门氏菌的生长。