Inhibition of low-density lipoprotein oxidation and oxidative burst in polymorphonuclear neutrophils by caffeic acid and hispidin derivatives isolated from sword brake fern (Pteris ensiformis Burm.)

Several antioxidant compounds have been previously identified from sword brake fern (Pteris ensiformis Burm.) by DPPH bleaching and Trolox equivalent antioxidant capacity (TEAC) analyses. Among the isolates, 7-O-caffeoylhydroxymaltol 3-O-beta-D-glucopyranoside and hispidin 4-O-beta- D-glucopyranoside [6-(3,4-dihydroxystyryl)-4-O-beta-D-glucopyranoside-2-pyrone] were two new compounds. The aim of this study is to elucidate the possible effect of the aqueous extract of sword brake fern (SBF) and these two compounds in preventing atherosclerosis. The results demonstrated that SBF and these two compounds strongly inhibited Cu2+-mediated low-density lipoprotein (LDL) oxidation measured by thiobarbituric acid-reactive substances assay (TBARS), conjugated diene production, and relative electrophoretic mobility. The commercial antioxidant dl-alpha-tocopherol showed lower antioxidant activity than these two compounds at the same molecular concentration. SBF and these two compounds also suppressed N-formylmethionyl-leucylphenylalanine (fMLP)-stimulated reactive oxygen species (ROS) production in human polymorphonuclear neutrophils (PMN). These findings indicate that sword brake fern may prevent atherosclerosis via inhibition of both LDL oxidation and ROS production.     

Aluminum inhibition of NADH‐linked electron transfer by corn root plasma membranes

Vesicles enriched in right‐side‐out plasma membranes were isolated from corn roots by a modified two‐phase partition method. Using reduced nicotinamide adenine dinucleotide as electron donor, isolated vesicles were capable of reducing both ferricyanide and oxygen. At pH 6.0, the presence of Al inhibited both reduction processes to a similar extent. This result indicates that these two reduction processes share at least one common step that is sensitive to Al. Inhibition was not associated with a change in the structure of the membrane domain, as revealed by fluorescence polarization of membrane incorporated probes. These results are the first indications that the electron transfer processes of plasma membranes are sensitive to the presence of Al.     

Molecular genetic and chemical assessment of radix Angelica (Danggui) in China

The roots of Angelica sinensis (Danggui), a traditional Chinese medicine, have been used for invigorating blood circulation for over 2000 years in China. Three common species of Angelica roots are found in Asia: A. sinensis from China, A. acutiloba from Japan, and A. gigas from Korea. By using a molecular genetic approach, the 5S-rRNA spacer domains of the three species of Angelica were amplified, and their nucleotide sequences were determined. Diversity in DNA sequences among various species was found in their 5S-rRNA spacer domains, which could serve as markers for authentic identification of Angelica roots. In chemical analyses, the main constituents of Angelica roots including ferulic acid and Z-ligustilide were determined by HPLC; roots of A. sinensis were clearly distinct in that they contained approximately 10-fold higher levels of ferulic acid and Z-ligustilide as compared to roots of A. acutiloba and A. gigas. In addition, the amounts of main constituents in roots of A. sinensis varied according to different regions of cultivation and different methods of preservation. The chemical profile determined by HPLC therefore could serve as a fingerprint for quality control of Angelica roots.     

基于智能手机平台的猪饲料配方系统设计与实现

设计依猪只个体日龄、体重等参数而异的饲料配方是实现猪精细饲养的关键,目前已有很多具备此功能的饲料配方软件,但它们大多数基于PC平台。结合智能手机便于携带、可移动性好等优点开发的基于智能手机平台的猪饲料配方软件,便于携带且操作简单,使用NRC1998模型精确预测了猪营养需要量,配方结果更准确科学,饲料原料营养成分数据用XML文件贮存,数据读取方便,有效地降低了系统开发成本。     

电子鼻对草莓采后贮藏早期霉菌感染的检测

为了实现电子鼻对草莓贮藏期常见霉菌感染的早期检测,对草莓果实分别接种灰霉、扩展青霉和根霉3种主要病原菌,以无菌水处理为对照组,每2d采用PEN3电子鼻获取草莓的气味,并用气质联用技术分析草莓气味。结果表明,草莓接种病原菌2d后,主成分分析能够正确区分正常果实(对照组)与病害果实,且可以较好区分草莓感染病原菌种类,多元方差分析结果也显示接种不同病原菌对草莓果实挥发性物质的影响差异显著(P<0.05),通过Fisher判别建立的回归函数对3种病原菌灰霉、扩展青霉和根霉及对照组的判别正确率分别为100%、93.3%、86.7%和100%。载荷分析及气质联用技术结果表明病原菌对草莓果实挥发性物质的影响主要体现在烃类及酯类的变化。研究结果可为实现草莓采后贮藏和流通过程中质量变化和病原微生物的感染进行无损快速检测和监测提供参考。     

Degradation pathway of dicyclanil in water in the presence of titanium dioxide. Comparison with photolysis

The solar photolytic behavior of the pesticide 4,6-diamino-2-cyclopropyl-pyrimidine-5-carbonitrile, currently known as dicyclanil, has been mimicked in a photoreactor operating with an artificial light flux. The rate and pathway of degradation were performed. An additional study, using TiO(2) photocatalysis, has been achieved in order to determine the efficiency of photocatalysis to degrade the molecule. The catalyst was titania Degussa P-25. The aim of this article was the identification of the intermediate products formed during the irradiation, to establish the degradation pathway of dicyclanil. The kinetics of the reactions were followed by liquid chromatography with a diode array detector (LC-DAD). Most of the organic compounds occurring during the photodegradation have been identified by means of liquid chromatography and mass spectrometry coupled techniques (HPLC-MS). Additional analyses were carried out to evaluate the mineralization rates into nitrate and ammonium ions.     

超高压微射流对花生蛋白结构的影响（简报）

为了探讨超高压微射流对花生蛋白理化性质和结构的影响,该文研究了花生蛋白溶液经超高压微射流处理后的颗粒大小、游离巯基基团、疏水基团和紫外吸收基团的变化规律。结果表明：花生蛋白的颗粒尺寸和游离巯基基团含量随着超高压微射流均质压力的增大而显著减小;疏水基团和紫外吸收基团的含量则随着均质压力的增大而显著增大,说明超高压微射流处理可破坏花生蛋白的内部基团,使蛋白的结构发生变化。     

Comparison of the chemical constituents of aged pu-erh tea, ripened pu-erh tea, and other teas using HPLC-DAD-ESI-MSn

Pu-erh tea is a popular beverage in southwestern China and South Asian countries. To explain the differences of aged pu-erh tea and ripened pu-erh tea, the chemical constituents of these teas were identified by HPLC-DAD-ESI-MS(n). In addition, HPLC was used to determine the contents of the major polyphenols, gallic acid, caffeine, and theobromine, in various types of teas. These results showed that the majority of chemical constituents in ripened pu-erh tea and aged pu-erh tea were similar, but the contents of catechins and gallic acid presented significant differences between these two teas. After fermentation by microorganism, the levels of catechins in ripened pu-erh tea were decreased, but the contents of gallic acid and caffeine were conversely elevated compared with aged pu-erh tea.