Antimutagenic activity of natural phenolic compounds present in the common bean ( Phaseolus vulgaris ) against aflatoxin B 1

Polyphenols with antimutagenic and anticarcinogenic properties are present in fruits, vegetables and legumes. In this study, the Salmonella typhimurium tester strains TA98 and TA100 were used in the microsuspension assay to examine the antimutagenic effect of phenolic compounds extracted from the common bean (Phaseolus vulgaris) against mutagenicity induced by aflatoxin B 1 (AFB 1 ). A dose-response curve was constructed for AFB 1 ; from which a level of 40ng AFB 1 /tube was selected for all antimutagenicity assays. The AFB 1 and phenolic extract (PE) were not toxic to the bacteria at concentrations tested. In the case of PE, results were similar to the number of spontaneous revertants for TA98 and TA100. The inhibitory effect of PE against AFB 1 mutagenicity was dose-dependent at the lower concentrations tested (2.5, 5, 10, 12.5, 15 and 25 μg-equivalent ( + )-catechin/tube for TA98; 0.5, 1, 1.5, 2.5, 5, 10 and 25 μg-equivalent ( + )-catechin/ tube for TA100). Further, a two-stage incubation procedure was used to investigate the potential interaction between PE and AFB 1 . The greatest inhibitory effect of the PE on AFB 1 mutagenicity occurred when PE and AFB 1 were incubated together. When the bacteria were first incubated with PE followed by a second incubation with AFB 1 , lower inhibition was observed. Lower inhibition was also observed when the bacteria were first incubated with AFB 1 followed by a second incubation with PE. The results suggest that the mechanism of inhibition could involve the formation of a chemical complex between of PE and AFB 1 .     

Rapid degradation of the mycotoxin patulin in man quantified by stable isotope dilution assays

The absorption and degradation of the mycotoxin patulin in man was quantified by using a recently developed stable isotope dilution assay. Application of this currently most sensitive method revealed a patulin content less than 200 ng l -1 in the blood serum of five consumers of apple juice. Likewise, no patulin was found in the serum of a volunteer, whose blood was drawn shortly after consumption of a juice containing a maximum tolerable amount of patulin. In further in vitro experiments, the degradation of patulin by reacting it with whole blood was investigated. After addition of 100 μg patulin to 9 ml blood, only 6.1% of the mycotoxin was detected after 2 min. It was concluded, therefore, that even high naturally occurring concentrations of patulin in foods are quickly degraded before reaching other tissues than the gastrointestinal tract.     

国产碱性脂肪酶的测定方法及特性研究

对几种国产脂肪酶的酶学特性进行了研究,并以酸碱滴定法对碱性脂肪酶的测定方法进行了探讨。结果表明:底物的乳化均匀程度对酶活力的测定有一定的影响,在α为0.05、经T检验得到:乳化、非乳化条件下及乳化液和缓冲液分开吸取和混合液乳化后吸取存在显著差异。SZ酶、SZX酶、SH酶在相同底物浓度下的最佳作用pH分别为9.0、8.9、9.1;最佳作用温度为35℃、35℃和45℃;达到最高活性所用的反应时间分别为15、10和10min。     

Rejection of endocrine disrupters contained in biologically treated sewage by nanofiltration

Two commercial nanofiltration membranes, NF-1 (low salt rejection) and NF-3 (medium salt rejection), were used for basic experiments on the rejection of endocrine disrupters of 17βestradiol,p-nonylphenol, bisphenol A and their mixed solution. Nanofiltration membrane experiments were carried out under low trans-membrane pressure of 0.5 MPa as the operating condition. For the two nanofiltration membranes, the rejection factor was high when the pH of each feed solution was not adjusted. Based on the results of the nanofiltration membrane experiments, four commercial nanofiltration membranes-NF-1, NF-2 (medium salt rejection), NF-3 and NF-4 (high salt rejection)-were used for the rejection of endocrine disrupters contained in biologically treated sewage. The biologically treated sewage concentration of 0.039–0.055 μg/Las 17Βestradiol equivalent was reduced by each nanofiltration membrane to 0.026 μg/ L(NF-1), 0.025 μg/L(NF-2), 0.003 μg/L(NF-3) and 0.009 μg/L(NF-4), as 17βestradiol equivalent, respectively. The rejection efficiency of endocrine disrupters showed the same tendency as the TOC rejection efficiency. The permeate flux of nanofiltration membranes was high in the order of NF-1, NF-3, NF-2 and NF-4.     

RP—HPLC法测定(7-甲氧基-3,4-二氢-1-萘基)乙腈的含量及其有关物质

目的:采用反相高效液相色谱法测定(7-甲氧基-3,4-二氢-1-萘基)乙腈含量及其有关物质。方法:采用Diamonsil~(TM)(钻石)C_(18)(250mm×4.6mm,5μm)色谱柱,流动相为甲醇-水(68:32),检测波长232nm,流速0.8mL/min。结果:此色谱条件下(7-甲氧基-3,4-二氢-1-萘基)乙腈与有关物质能达到有效分离,在40.48～161.92 μ g/mL范围内线性关系良好,r=0.9998;仪器精密度RSD为0.94%;方法重复性RSD为1.3%;最低检测限4.9ng。结论:该方法简便、准确、可行,可用于(7-甲氧基-3,4-二氢-1-萘基)乙腈的质量控制。     

Soybean Trypsin Inhibitor Assay: Further Improvement of the Standard Method Approved and Reapproved by American Oil Chemists’ Society and American Association of Cereal Chemists International

For measuring trypsin inhibitor (TI) activities in soybean products, the current standard method, approved and reapproved by American Oil Chemists Society (Method Ba 12-75) and American Association of Cereal Chemists International (Method 22-40.01), features mixing trypsin with a series of inhibitor levels and then adding a substrate to start the colorimetric reaction. Yet, previous studies have shown flaws with the method, particularly with using several inhibitor levels and the sequence of adding the substrate last. The present study showed that with varying levels of dilution and volumes of a dilute sample extract, the pH of the premix (the mixture of a dilute sample extract and trypsin solution) ranged 3.30–3.60 for raw soy flour, and 3.20–6.70 for toasted soy. Within these premix pH ranges, the standard method of adding substrate last would give TI values equal to or less than those measured by the same method except for adding the enzyme last. The standard method was subsequently improved by using a single sample extract level and the enzyme-last sequence. Other modifications included making stock solutions for reagents, adding Ca²⁺ to the trypsin solution, diluting sample extracts to a level that causes 30–70% of inhibition, and running both reference and sample blanks for better controls. Alternatively, the full volume assay (10 mL total, as in the standard method) was further modified by using half the volume of each reagent with the same concentration. Compared to the standard method, the improved methods gave more consistent results when assaying 11 selected soy products. The half volume (5 mL) and full volume methods gave the same results, but the former could increase assay sensitivity and reduce amounts of reagents used.     

2种用于检测市售核桃露(乳)饮品中花生、大豆成分方法的比较分析

摘 要: 目的 比较实时荧光定量PCR法与酶联免疫吸附法在核桃露(乳)饮品中检测花生和大豆成分的灵敏性的差异。方法 应用实时荧光定量PCR方法检测样本DNA的核桃、花生和大豆源性成分, 应用酶联免疫吸附法(enzyme linked immunosorbent assay, ELISA)检测样本的花生和大豆特征蛋白成分。结果 加热处理对实时荧光PCR和ELISA法检测花生和大豆的结果均有显著性影响。实时荧光定量PCR方法检出2个品牌4批次样本含有花生源性, 3个品牌的6批次样本含有大豆源性; ELISA方法除检出这些批次含有花生和大豆源性成分外, 另检出3个品牌5批次样本含有大豆源性成分。ELISA方法与实时荧光定量PCR方法的大豆检测结果差异主要集中在低蛋白浓度样品中, 这与2类方法的检出限不同有关。结论 鉴于2类方法检测结果在高浓度水平的高度一致性, 说明实时荧光PCR和ELISA方法对花生和大豆源性成分检测结果均具有很高的可靠性。     

Development and validation of a rapid HPLC method for the determination of ketotifen in pharmaceuticals

In the present study, a simple, sensitive, rapid, and stability-indicating high performance liquid chromatographic (HPLC) method with ultraviolet detection for the analysis of ketotifen was developed and validated. The method was applied to the determination of ketotifen in pharmaceutical formulations (tablets and syrups). The HPLC method utilized isocratic elution technique with a reversed phase C8 column, detection at 297 nm and a mixture of methanol, triethylamine phosphate buffer (pH 2.8; 0.04 M), and tetrahydrofuran (43: 55: 2, v/v/v) as mobile phase at a flow rate of 1.2 mL/min. Total analysis time was about 7 min with typical retention time of ketotifen of about 5 min. The method was validated for selectivity, linearity, accuracy, and precision following International Conference of Harmonization, 1996 (ICH) recommendations. Due to its simplicity and accuracy, the method can be used for routine quality control analysis.     

世界油页岩开发利用现状及预测——并记2010年国内外两次油页岩会议

介绍了世界油页岩开发利用现状,并记2010年美国第30届国际油页岩会议及国内油页岩年会上的主要报告内容。重点介绍了中国、爱沙尼亚、巴西、美国、加拿大、德国、约旦和澳大利亚等15个国家的油页岩最新发展。当前,世界上油页岩干馏生产页岩油的国家有中国(55×104t/a)、爱沙尼亚(40×104t/a)和巴西(18×104t/a),爱沙尼亚还正建设颗粒页岩干馏新工艺的大型工业装置,中国则正引进颗粒页岩干馏的大型工业装置,并自主创新筹建粉末及颗粒页岩干馏的工业试验装置。美国至今仍无页岩油的工业生产,但现有约30家公司、研究所和大学在进行油页岩地下和地上干馏炼油的开发和基础研究。当前,世界上利用油页岩燃烧产汽发电的国家有爱沙尼亚、中国、以色列等,爱沙尼亚油页岩电站生产规模很大(所发电量占其所需电力的94%),其他国家规模较小。中国页岩油仍不断增产,并在引进和自主开发油页岩干馏生产页岩油的新工艺。由于中国当前每年进口大量原油,对外依存度超过50%,故页岩油的生产受到重视。国家发改委等制定有支持油页岩产业发展的政策和税收优惠的规定。中国预测的页岩油资源很丰富,但探明储量不够多,建议在"十二五"期间加强勘查,落实更多可采储量,才可能使页岩油生产量大幅增加。中国石油大学(北京)编写了油页岩专著的英文本,于2010年6月由中国石化出版社出版,面向全世界发行。