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.     

生活污水对蚕豆根尖细胞致畸效应的研究

以蚕豆根尖为材料,采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,研究不同取样点生活污水对蚕豆根尖细胞的致畸效应.结果表明:生活污水能诱发微核率升高,而且在一定范围内,其微核率随污染物浓度升高而增加,但高于一定浓度后有下降趋势;不同取样点的污水均使蚕豆根尖细胞有丝分裂指数下降;生活污水还能诱导蚕豆根尖细胞产生较高频率的染色体畸变.所以生活污水蚕豆根尖细胞具有明显的致畸效应.     

不同菌种发酵对蚕豆酱风味成分的影响

本试验采用顶空固相萃取结合气质联用的技术检测由米曲霉、黑曲霉、根霉、毛霉4种不同单一菌种发酵的蚕豆酱在后发酵15d和40d两个时期酱醅中的香气成分。数据表明各菌种发酵的蚕豆酱在后发酵15d至40d酱醅中的挥发性成分变化较大,主要特征风味物质种类不断丰富。在后发酵前期阶段蚕豆酱中醇类和酸类物质占主要地位,随着发酵时间的延长,蚕豆酱中的醛类、酯类和杂环类物质含量会上升,而酮类及酸类物质减小。由米曲霉、黑曲霉、根霉及毛霉纯种发酵制作的4种酱中主要的特征风味物质有2,3-丁二醇、3-甲基丁醇、2-甲基丁醇、芳樟醇、苯乙醇、苯甲醛、苯乙醛、琥珀酸-3,4-二甲基苯基庚基酯、三甲基吡嗪等,且由米曲霉发酵的蚕豆酱风味物质较丰富,该菌种是制作蚕豆酱的良好发酵剂。     

Accelerated Fermentation Process for the Manufacture of Fish Sauce Using Histidine

Addition of histidine accelerated hydrolysis of fish protein during fermentation in the manufacture of fish sauce and after 4 mo fermentation yielded a product typical of traditional fish sauce. The liquefaction rate of the histidine-treated sauce was faster than that of the control. The degree of hydrolysis was much greater in the histidine-added sauces than in the control. Most amino acids were higher in the histidine sauces compared to commercial patis sauce (as reference). Addition of histidine to the fish mixture during fermentation did not increase the histamine content of the sauces.     

Evolution of soluble carbohydrates during the development of pea, faba bean and lupin seeds

Seeds of pea (Pisum sativum L. cv. Ergo), faba bean (Vicia faba ssp. minor Harz., cv. Tibo) and yellow pea lupin (Lupinus luteus L. cv. Juno) were sampled at different days after flowering (DAF) and their content of soluble carbohydrates was determined: Analysis of samples showed thatmyo-inositol, fructose, glucose, galactose and sucrose were found in high abundance early in development and their content decreased gradually during maturation. -Galactosides, which includes the content of raffinose, stachyose and verbascose, started to appear later in seed development, at 37 DAF in peas, 40 DAF in faba beans and 45 DAF in lupins. Their accumulation increased considerably during seed growth, and the maximum content was obtained in mature seeds; 3.8% in peas, 4.5% in faba beans and 10.4% in lupins. Results obtained for these sugars during seed development were fitted to modelling curves in order to predict sugar content at different development stages.     

基于EJB 技术的网络教学系统的设计与实现

分析了网络教学系统的总体需求,运用实体EJB、会话EJB进行组件设计,说明了系统的设计原则与系统的主要功能.     

Isolation of the acidic and basic lectins from winged bean seed (Psophocarpus tetragonolobus (L.) DC)

The acidic and basic lectins of the winged bean were isolated from seed extracts by affinity chromatography on lactose-Sepharose 6B and melibiose Bio-Gel P150, respectively. The lectins isolated from six varieties of Psophocarpus tetragonolobus, collected from different regions of south-east Asia, showed no significant differences in their properties; their subunit M_r and amino acid compositions were the same as those of the acidic and basic lectins isolated by non-affinity methods. On isoelectric focusing the affinity purified acidic lectins showed two major protein components (isolectins) while the affinity purified basic lectins had four protein components. The acidic lectins showed a preference for β-D-galactosides and they agglutinated trypsinised human type A, B and O erythrocytes but not trypsinised rabbit erythrocytes. The basic lectins showed a preference for α-D-galactosides and they agglutinated trypsinised rabbit and human type A and B erythrocytes but not trypsinised human type O erythrocytes.     

四棱豆油脂、脂肪酸、蛋白质、氨基酸的分析

以4 个四棱豆品种的种子为材料,采用索式提取法、毛细管柱测定总脂肪含量及分析各脂肪酸含量;利用凯氏定氮法、全自动氨基酸分析仪测定蛋白质总量及各蛋白氨基酸组成。结果表明,四棱豆种子中油脂总量在20%～22%,主要含有28 种脂肪酸,油酸占单不饱和脂肪酸的90.7%;多不饱和脂肪酸主要为亚油酸、α - 亚麻酸和EPA;饱和脂肪酸平均含量为25.76%,主要为棕榈酸和硬脂酸。蛋白质总量在38% 左右,必需氨基酸含量丰富。     

Ion irradiation—induced structure damage to botanic samples using the ion transmission energy spectrum

1 INTRODUCTIONThe new aPplications of low energy heavy ion beam in irradi4ted botanical materialswere studied in recellt yeaxs. The beaminduced mutation effect on crop seeds has causedthe attention of physicist and biologists.[1l:] FOr examPle, 1ow energy ions can induceremarkable mutation to rice seeds.[3] There are many special phenomena when heavyions bombard botanic sW1e due to its special structure. Some studies showed that tllepenetration depths of some ions were far larger than t…