UPLC-MS/MS法同时检测大鼠体内7-乙基-14-氨基喜树碱及其代谢产物

建立了同时定量测定SD大鼠血浆中7-乙基-14-氨基喜树碱（EAC）及内酰胺型代谢产物（EAC-M）的UPLC-MS/MS方法。血浆样品经乙腈沉淀蛋白处理后,以Phenyl-Hexyl柱（2.1 ×50 mm,1.8 μm）为分离柱,以5mM醋酸铵水溶液（含0.1%甲酸）-乙腈为流动相梯度洗脱,流速0.5 ml/min。洗脱物经电喷雾离子源（ESI）正离子化,以多反应监测模式（MRM）测定EAC（m/z 392→291）和EAC-M（392→290）。内源性物质不干扰测定;EAC与EAC-M的线性范围均为0.500~250 ng/mL,定量下限0.500 ng/mL。日内、日间精密度（RSD）小于7.6%,准确度（RE）-4.2～5.9%;回收率为84.4~98.7%,基质效应的RSD小于5%。所建立的方法简便、灵敏、选择性强,适用于SD大鼠血浆中EAC及代谢产物EAC-M的测定和药代动力学研究。     

小红豆抗菌蛋白的分离纯化及其功能活性

研究旨在从小红豆中分离纯化得到一种具有抗菌活性的蛋白,对其部分生物活性进行表征和研究。通过缓冲液抽提（NaAc-HAc,20 mmol/L,pH5.4）、硫酸铵分级沉降、Affi-gel blue gel亲和色谱、Sephadex SP C-25离子交换色谱及Sephadex G-50凝胶过滤色谱进行分离纯化,经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析鉴定其相对分子质量,并对其抗真菌活性进行表征。结果表明,从小红豆中分离纯化出的一种抗菌蛋白,经SDS-PAGE鉴定达到电泳纯,且其相对分子质量约为4 kDa,通过纯化的抗菌蛋白对来自茄子、甜瓜及苦瓜的尖孢镰刀菌的抑制实验,证明此抗菌蛋白具有较强的抗真菌活性。从小红豆中分离纯化出的一种分子质量约为4 kDa的抗菌蛋白,其对真菌具有抑制作用,且其抑制率对浓度的依赖性较高。      

三种海藻内生真菌的分离及其抑菌活性研究

从烟台浅海处采集到的鼠尾藻、裙带菜、海带三种海藻表面消毒后用PDA培养基将内生真菌进行分离纯化,将纯化的内生真菌进行液体培养7d后离心,菌丝体烘干研磨后用无水乙醇提取,分别测定发酵液和菌丝体乙醇提取物对七种植物病原真菌的抑菌活性。结果表明:三种发酵液都至少对三种病原菌有大于50%的抑菌活性,裙带菜发酵液对六种病原菌都有大于50%的抑菌率,最高为78.8%,说明它们能产生广谱高效的胞外代谢产物;而菌丝体提取物的抑菌活性并不明显,说明三种海藻内生真菌产生的胞内代谢产物无明显的抑菌活性。     

Synthesis and antifungal activity of analogues of naturally occurring botrydial precursors

Analog compounds of the proposed intermediates of the biogenetic pathway to botrydial have been synthesized. These compounds were tested for their potential antifungal activity against the phytopathogenBotrytis cinerea. Our results showed a fungistatic effect of some compounds on mycelium growth. The most significant effect was exerted by 2--hydroxy-2,3-dihydro-1-epiprobotrydial, which inhibited growth ofB. cinerea. Some aspects of structure-activity relationships are discussed.     

Allolaurinterol类倍半萜的分离合成及生物活性研究进展

Allolaurinterol类倍半萜具有良好抗菌活性,显示了广泛的应用前景。本文综述了国内外近几十年来Allolaurinterol类倍半萜的分离、合成及生物活性的研究进展,并对其发展趋势和应用前景作了展望。     

Identification of predictive biomarkers of disease state in transition dairy cows

In dairy cows, periparturient disease states, such as metritis, mastitis, and laminitis, are leading to increasingly significant economic losses for the dairy industry. Treatments for these pathologies are often expensive, ineffective, or not cost-efficient, leading to production losses, high veterinary bills, or early culling of the cows. Early diagnosis or detection of these conditions before they manifest themselves could lower their incidence, level of morbidity, and the associated economic losses. In an effort to identify predictive biomarkers for postpartum or periparturient disease states in dairy cows, we undertook a cross-sectional and longitudinal metabolomics study to look at plasma metabolite levels of dairy cows during the transition period, before and after becoming ill with postpartum diseases. Specifically we employed a targeted quantitative metabolomics approach that uses direct flow injection mass spectrometry to track the metabolite changes in 120 different plasma metabolites. Blood plasma samples were collected from 12 dairy cows at 4 time points during the transition period (−4 and −1 wk before and 1 and 4 wk after parturition). Out of the 12 cows studied, 6 developed multiple periparturient disorders in the postcalving period, whereas the other 6 remained healthy during the entire experimental period. Multivariate data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation between healthy controls and diseased cows at all 4 time points. This analysis allowed us to identify several metabolites most responsible for separating the 2 groups, especially before parturition and the start of any postpartum disease. Three metabolites, carnitine, propionyl carnitine, and lysophosphatidylcholine acyl C14:0, were significantly elevated in diseased cows as compared with healthy controls as early as 4 wk before parturition, whereas 2 metabolites, phosphatidylcholine acyl-alkyl C42:4 and phosphatidylcholine diacyl C42:6, could be used to discriminate healthy controls from diseased cows 1 wk before parturition. A 3-metabolite plasma biomarker profile was developed that could predict which cows would develop periparturient diseases, up to 4 wk before clinical symptoms appearing, with a sensitivity of 87% and a specificity of 85%. This is the first report showing that periparturient diseases can be predicted in dairy cattle before their development using a multimetabolite biomarker model. Further research is warranted to validate these potential predictive biomarkers.     

Effect of Zingiber officinale Roscoe essential oil in fungus control and deoxynivalenol production of Fusarium graminearum Schwabe in vitro

ABSTRACT

Members of the Fusarium genus are capable of contaminating agricultural commodities, compromising the quality of maize and other grains, which leads to severe quality and yield losses. Contamination with mycotoxins is also a concern. Essential oils are possible alternatives to the use of synthetic pesticides for control of fungal contamination, as many have antifungal and anti-mycotoxigenic properties and are innocuous to human health. They also do not cause any sort of microbial resistance and do not promote environmental pollution. The aim of this study was to evaluate the antifungal and anti-mycotoxigenic effects of Zingiber officinale Roscoe essential oil (GEO) upon Fusarium graminearum Schwabe in vitro. The essential oil was extracted by hydrodistillation and analysed by GC/MS. Antifungal and anti-mycotoxigenic activities were assessed by HPLC/UV by quantifying ergosterol and deoxynivalenol (DON), respectively. Results indicated that GEO inhibited ergosterol production at a concentration of 1000 µg/mL and DON production at a concentration of 500 µg/mL, evidencing that the anti-mycotoxigenic effect is independent of the antifungal effect due to its probable direct action upon toxin biosynthesis.     

Alterations in milk metabolome and coagulation ability during the lactation of dairy cows

Milk composition has been known to change during lactation. To help understand the changes in metabolic profile throughout the whole lactation, liquid chromatography mass-spectrometry was used to analyze 306 milk samples from 82 primi- and multiparous dairy cows. Changes in metabolic profile common to all cows throughout lactation were ascertained based on principal component and general linear model analysis. Sets of specific markers; for instance, 225, 397, and 641–642 m/z (positive mode), and 186, 241, and 601–604 (negative mode), with at least a 1.5-fold higher intensity during the first 60 d compared with the last 60 d of lactation were observed. The metabolome was affected by parity and milking time. Markers, identified as peptides differentiating parity, were observed. A significant increase for citrate was observed in evening milk. Milk coagulation traits were strongly animal specific. The curd firmness values were influenced by milking time. Sets of markers were associated with curd firmness in positive (197 m/z) and negative (612, 737, 835, 836, 902, 1000, 1038, and 1079 m/z) ion mode.     

Microfluidic technologies for synthetic biology

Microfluidic technologies have shown powerful abilities for reducing cost, time, and labor, and at the same time, for increasing accuracy, throughput, and performance in the analysis of biological and biochemical samples compared with the conventional, macroscale instruments. Synthetic biology is an emerging field of biology and has drawn much attraction due to its potential to create novel, functional biological parts and systems for special purposes. Since it is believed that the development of synthetic biology can be accelerated through the use of microfluidic technology, in this review work we focus our discussion on the latest microfluidic technologies that can provide unprecedented means in synthetic biology for dynamic profiling of gene expression/regulation with high resolution, highly sensitive on-chip and off-chip detection of metabolites, and whole-cell analysis.