手性金属配合物d-[Co（EDTA）]^-和ι-[Co（EDTA）]^-经Caco-2细胞单层模型的转运吸收

采用动力学研究方法测定了手性金属配合物d-[Co（EDTA）]^-和ι-[Co（EDTA）]^-跨Caco-2细胞单层的转运速率。研究发现,由于金属配合物的手性差异,导致d-[Co（EDTA）]^-和ι-[Co（EDTA）]^-经Caco-2细胞单层的转运速率明显不同;手性金属配合物经Caco-2细胞单层转运吸收时存在手性选择性,表明小肠对手性金属配合物药物可能有选择性吸收;d-[Co（EDTA）]^-和ι-[Co（EDTA）]^-经Caco-2细胞单层的转运依赖浓度梯度驱动,说明该对映体配合物经Caco-2细胞单层转运吸收时存在简单扩散的转运方式。     

手性金属配合物d-[Co(EDTA)]-和l-[Co(EDTA)]-经Caco-2细胞单层模型的转运吸收

采用动力学研究方法测定了手性金属配合物d-[Co(EDTA)]-和l-[Co(EDTA)]-跨Caco-2细胞单层的转运速率. 研究发现, 由于金属配合物的手性差异, 导致d-[Co(EDTA)]-和l-[Co(EDTA)]-经Caco-2细胞单层的转运速率明显不同; 手性金属配合物经Caco-2细胞单层转运吸收时存在手性选择性, 表明小肠对手性金属配合物药物可能有选择性吸收; d-[Co(EDTA)]-和l-[Co(EDTA)]-经Caco-2细胞单层的转运依赖浓度梯度驱动, 说明该对映体配合物经Caco-2细胞单层转运吸收时存在简单扩散的转运方式.     

体外细胞模型和高效液相质谱联用分析预测黄芪中的活性成分

利用体外细胞模型模拟体内细胞对中药有效成分的特异性吸收,结合高效液相色谱/质谱分析筛选中药黄芪中的生物活性成分。将中药黄芪提取液与Caco-2细胞及红细胞分别混合培养,破碎与药材结合后的细胞,使之释放出结合的药材中的成分。运用高效液相色谱/飞行时间质谱(HPLC-ESI/TOFMS)分析中药黄芪提取液与活性细胞有结合的成分,并对其进行结构鉴定。结果显示:黄芪中有10个化合物与Caco-2细胞结合,14个化合物与红细胞结合。本方法可用于预测口服药物在体内的吸收以及与特定靶细胞的结合情况,特异性地筛选中药复杂体系中的药效物质基础。     

应用先进光谱技术研究无机离子的环境界面化学

发生在环境界面的吸附-解吸和氧化-还原等反应对于污染物在环境介质间传输、转化以及归趋起着重要的调控作用。传统的研究方法虽然可以在实验室模拟并进而描述污染物环境界面过程,但是不能揭示界面反应机制,限制了对污染物环境界面行为的认识。近二十年来,各种谱学技术(例如X射线吸收精细结构和傅里叶红外光谱等)应用于环境界面反应的研究,推动了这一领域研究的发展,特别是在分子水平研究污染物的环境界面过程。通过现代光/波谱技术原位分析,可以实时获取界面反应的定量与结构信息,从而更准确地判断反应机制,极大促进了对污染物在多介质环境界面迁移转化规律的认识。本文将在概述环境界面化学反应的基础上,针对无机离子在环境界面的反应过程,重点介绍几种关键光/波谱技术(X射线吸收精细结构光谱、傅里叶红外光谱、拉曼光谱、核磁共振谱和穆斯堡尔谱等)在环境界面化学研究中的应用,并展望其在环境界面过程研究中的应用前景。     

秸杆燃烧对环境的化学作用

初步探讨了秸杆焚烧产生的颗粒物、多环芳烃化合物、NO2、SO2等化学污染物对环境的污染及毒害作用,有助于人们对秸杆焚烧危害性的认识,提高环境意识,开发利用秸杆。     

硅对农作物生长的影响

硅元素在地壳中含量排位第2，作为非金属材料已广为熟知，它与农作物的生长密切相关。回顾了硅元素的研究历程，介绍了硅元素的性质、在土壤中的分布特点和存在形态。综述了硅在提高农作物抗逆能力如抗旱、抗倒伏、耐盐碱、耐高温等方面的研究进展，评述了硅在协调并促进农作物对营养物质的吸收，缓解重金属离子的毒害作用，抵御病虫害的侵袭方面的作用规律和机制。分析了硅元素调节农作物生长的机理和条件，从基因角度分析农作物对硅元素的吸收和转运。探讨了硅肥和有机硅表面活性剂在促进农业可持续发展过程中的重要作用。     

PBDEs研究的最新进展

多澳联苯醚(PBDEs)是一类环境中广泛存在的全球性有机污染物.由于其具有环境持久性、远距离传输、生物可累积性及对生物和人体具有毒害效应等特性,对其环境问题的研究已成为当前环境科学的一大热点.本文对最近几年来环境中PBDEs研究的进展进行综述,对多溴联苯醚在环境及生物体中的分布、时间趋势、人体暴露及途径、环境中的降解和生物代谢以及生物累积与生物放大方面的研究进行了总结,对目前存在问题及进一步的研究方向进行了讨论和展望.     

水的溶剂效应对植物防晒剂UV-B吸收的影响（英文）

抵御UV-B(280～320 nm)对地球生命至关重要.研究UV-B防晒分子周边的环境对UV-B吸收的影响有助于了解防晒剂的光吸收机制.水作为溶剂在细胞中无处不在,但是其对防晒剂吸收UV-B的影响还未被充分研究.本文基于第一性原理,重点研究了芥子酸酯及其相关植物防晒分子的UV-B吸收中水的溶剂作用.芥子酸酯阴离子对UV-B的吸收作用来自与其周边水溶剂环境的相互作用,因此其也是在实际环境中起到防晒功能的防晒物种.在第一性原理模拟中,隐式水溶剂模型可以提供溶剂化的介电环境,显式水溶剂模型可以与芥子酸酯阴离子形成氢键,这些因素都可以显著改变与芥子酸酯阴离子吸收UV-B相关的跃迁轨道性质.同时,发现了植物防晒剂的分子偶极矩可以作为衡量其UV-B吸收能力对周围极性环境敏感程度的指标.本工作为开发新型水溶性UV-B防晒剂提供了起点.     

海洋酸化条件下重金属和金属纳米颗粒的环境行为及其对海洋生物的影响

工业革命以来,海洋吸收人类排放的CO_2,导致地球表层海水碳酸盐浓度和pH持续下降,使得全球海洋出现酸化现象.海洋酸化(ocean acidification,OA)除直接威胁海洋生态系统的稳定外,还通过改变海洋污染物的环境行为间接改变其对海洋生物的毒性效应.本文以重金属和金属纳米颗粒(metallic nanoparticles,MNPs)等环境污染物作为主要的研究对象,通过对OA的成因进行深入分析,重点研究OA改变重金属的存在形态和影响金属纳米颗粒的溶解、悬浮、迁移等一系列过程的主要机理,探明这些重金属和MNPs的关键环境过程的改变对海洋生物个体的影响,并对其造成的毒性差异进行了重点分析.最后对OA与共存污染物毒性效应进一步需开展的研究工作进行了重点展望.     

季铵盐类化合物环境问题研究进展

季铵盐类化合物(quaternary ammonium compounds, QACs)是一类广泛使用的阳离子表面活性剂,在环境介质(水、沉积物、污泥等)中普遍存在,尤其在污泥/沉积物中其浓度可达数百甚至上千mg/kg水平。QACs具有高表面活性和中/高毒性,低浓度下即对鱼类、藻类、细菌和无脊椎动物等产生毒害作用,并显著影响与其共存污染物的迁移性和生物有效性,其环境问题已经引起发达国家广泛关注,但在我国研究尚未成熟。因此,本文综述了QACs在环境介质中的来源、分析方法、污染现状、环境行为及毒性效应,并讨论了目前研究存在的问题,以期为我国开展QACs环境问题的研究提供参考。     

Increasing the throughput and productivity of Caco-2 cell permeability assays using liquid chromatography-mass spectrometry: application to resveratrol absorption and metabolism

The Caco-2 cell monolayer permeability assay has become a standard model of human intestinal absorption and transport. This paper reviews recent progress in increasing the throughput of Caco-2 cell monolayer assays and in expanding the scope of this assay to include modeling intestinal drug metabolism. The state-of-the-art in Caco-2 cell monolayer permeability assays combines multi-well plates fitted with semi-permeable inserts on which Caco-2 cells have been cultured with liquid chromatography-mass spectrometry (LC-MS) or LC-tandem mass spectrometry (LC-MS-MS) for the quantitative analysis of test compounds and the identification of their intestinal metabolites. After reviewing the progress in increasing the throughput of Caco-2 cell monolayer assays for both modeling human intestinal permeability or transport and the metabolism of xenobiotic compounds, we demonstrate the application of LC-MS and LC-MS-MS to the measurement of resveratrol permeability and metabolism in the Caco-2 model. trans-Resveratrol (trans-3,5,4'-trihydroxystilbene) is a polyphenolic compound occurring in grapes, peanuts and other food sources, that is under investigation as a cancer chemoprevention agent. The apparent permeability coefficient for apical (AP) to basolateral (BL) movement of resveratrol was 2.0 x 10(-5)cm/sec. Resveratrol was not a substrate for P-glycoprotein or the multi-drug resistance associated proteins (MRP). No phase I metabolites were observed, but the phase II conjugates resveratrol-3-glucuronide and resveratrol-3-sulfate was identified based on LC-MS and LC-MS-MS analysis and comparison with synthetic standards. Although these data indicate that resveratrol diffuses rapidly across the intestinal epithelium, extensive phase II metabolism during absorption might reduce resveratrol bioavailability.     

Studies on the intestinal absorption of the alkaloids in the Gancaofuzi decoction in a Caco-2 cell culture system by UPLC–MS/MS analysis

In this study, the Caco-2 cell monolayer model was used to research the characteristic absorption and efflux of five diterpenoid alkaloids in Gancaofuzi decoction. An ultra performance liquid chromatography coupled with tandem mass spectrometry(UPLC–MS/MS) method was developed for the determination of the simulated intestinal transport of five diterpenoid alkaloids with reserpine as internal standard. The use of the apparent permeability coefficient(Papp) and efflux rate(Er) was instituted to evaluate the intestinal absorption of the alkaloids. Transport of the five alkaloids in Caco-2cell monolayer model was observed to better understand whether the intestinal absorption of alkaloids was influenced by the compatibility of four herbs in Gancaofuzi decoction. The results show that the Papp values of the five diterpenoid alkaloids were all more than 1 * 10~(-6)cm/s, confirming that the processes of permeability were valid. The flux of the alkaloids was time-dependent, and the intestinal absorption mechanism of the five alkaloids was mainly based on passive transport. The compatibility of Heishunpian, Baizhu, Guizhi and Gancao can reduce the intestinal absorption of alkaloids, especially the most toxic hypaconitine, and the attenuated effect of mixed herbal water extracts was better than that of different herbs' water extracts combination. The results prove that compatibility of four herbs in Gancaofuzi decoction is rational.     

Oenothein B in Eucalyptus Leaf Extract Suppresses Fructose Absorption in Caco-2 Cells

Inhibition of fructose absorption may suppress adiposity and adiposity-related diseases caused by fructose ingestion. Eucalyptus leaf extract (ELE) inhibits intestinal fructose absorption (but not glucose absorption); however, its active compound has not yet been identified. Therefore, we evaluated the inhibitory activity of ELE obtained from Eucalyptus globulus using an intestinal fructose permeation assay with the human intestinal epithelial cell line Caco-2. The luminal sides of a cell monolayer model cultured on membrane filters were exposed to fructose with or without the ELE. Cellular fructose permeation was evaluated by measuring the fructose concentration in the medium on the basolateral side. ELE inhibited 65% of fructose absorption at a final concentration of 1 mg/mL. Oenothein B isolated from the ELE strongly inhibited fructose absorption; the inhibition rate was 63% at a final concentration of 5 μg/mL. Oenothein B did not affect glucose absorption. In contrast, the other major constituents (i.e., gallic acid and ellagic acid) showed little fructose-inhibitory activity. To our knowledge, this is the first report that oenothein B in ELE strongly inhibits fructose absorption in vitro. ELE containing oenothein B can prevent and ameliorate obesity and other diseases caused by dietary fructose consumption.     

Studies on Intestinal Transport of Ginsenoside Compatibility with Veratrum nigrum via Caco-2 Cell Monolayer Model Coupled with UPLC-ESI-MS Method

The Caco-2 cells have been recognized as effective tools to be applied to imitating the drug absorption in human intestine for the transport of drug. Herein, Caco-2 cell monolayer model was used to study the transport of the ginsenoside compatibility with Veratrum nigrum in different proportions. A specific high performance liquid chromatography-electrospray ionization-mass spectrometry(HPLC-ESI-MS) method was developed for the semiquantitative determination of ginsenoside in intestinal transport with Dioscin as an internal standard. For the Caco-2 model constructed, two influencing factors were investigated, including time and concentration. The results suggest that the absorption of ginsenoside Re, Rg1, Rb1, Rc, Rb2 and Rd are time- and concentration-dependent and the excretions of Rb1, Rc, Rb2 and Rd have a relatronship with some transport proteins. The bioavailability of the ginsenosides has reduced compared to the single Panax ginseng extract when compatibility with a certain amount of Veratrum nigrum.     

Study on intestinal transport of Veratrum alkaloids compatible with Panax ginseng across the Caco-2 cell monolayer model by UPLC-ESI-MS method

The Caco-2 cells have been recognized as effective tools to be applied to imitate the drug absorption in human intestine for the transport of drug. In this study, Caco-2 cell monolayer model was used to study compatibility of the transport of the Veratrum alkaloids in different proportions with Panax ginseng. A specific ultra-high performance liquid chromatographic-electrospray ionization-mass spectrometric (UPLC-ESI-MS) method is developed for the semi-quantitative determination of Veratrum alkaloids on intestinal transport with berberine as internal standard (IS). In the Caco-2 model constructed, three influencing factors are investigated, including time, concentration and recovery rates of the Veratrum alkaloids during the uptake from AP (apical side) to BL (basolateral side). The results suggest that the flux of Veratrum alkaloids is time dependent and concentration dependent. And the absorption of all eight Veratrum alkaloids increase after compatibility with Panax ginseng compared to the single Veratrum nigrum extraction. This research was studied from the perspective of intestinal absorption by the UPLCESI-MSmethod. Thismethod was successfully applied to transport studies of the Veratrum alkaloids and the interaction mechanism between Veratrum nigrum and Panax ginseng.     

微生物燃料电池

微生物燃料电池 (Microbial Fuel Cells,MFCs) 是一种利用微生物作为催化剂,将燃料中的化学能直接转化为电能的装置。本文首先简要介绍了MFCs 的发展简史和基本原理,针对MFCs 产电性能低的现状,分别从产电微生物、电池结构、质子交换膜(PEM)、电极以及电解液等方面着重综述了近几年有关提高MFCs 产电性能的研究进展。最后介绍了关于MFCs 的另一些有趣的研究方向：植物MFCs,生物阴极MFCs,以及污水脱氮和有毒废水处理。     

Capillary zone electrophoresis-based cytotoxicity analysis of Caco-2 cells

A capillary zone electrophoresis-based method to evaluate the cytotoxicity of substances to Caco-2 cells was established. The estimation of the injected cell number (500-5000) and the minor effect of injection condition on cytotoxicity determination were investigated. Caco-2 cells the best model of the intestinal absorptive epithelium, were treated with substances and then stained with Trypan Blue and fixed with paraformaldehyde. The treated Caco-2 cells were detected simultaneously at 590 nm and 214 nm, and the absorbance ratio of the two wavelengths (R(590/214)) can reflect simultaneously the loss of cell membrane integrity and the degradation/leak of intracellular components and indicate the cytotoxicity of substances. The cytotoxicity of the four substances sodium sulfite (Na(2)SO(3)), methyl mercury (MeHg), paclitaxel (PTX), and cadmium chloride (CdCl(2)) were determined and compared. There was no obvious cytotoxicity caused by 20 μM Na(2)SO(3) for 24 h treatment, and the toxicity of the other three toxicants was sequenced as: CdCl(2) > MeHg > PTX. The results are in good agreement with the references and the conventional Trypan Blue exclusion counting assay.     

The intragastrointestinal fate of paclitaxel-loaded micelles: Implications on oral drug delivery

The goal of the present study is to elucidate the intragastrointestinal fate of micellar delivery systems by monitoring fluorescently labeled different micelles and the model drug paclitaxel (PTX). Both in vitro and ex vivo leakage studies showed fast PTX release in fluids while micelles remained intact, except in fed-state simulated intestinal fluid and fasted-state pig intestinal fluid, thus referring to the intact absorption of micelles and PTX leakage in the gastrointestinal tract with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) micelles showing higher stability than other micelles. All groups of micelles were absorbed intact in Caco-2 and Caco-2/HT29-MTX cell models and the absorption of TPGS micelles was found to be higher than other micelles. The transport of the micelles across Caco-2/Raji (1.6%–3.5%), Caco-2 (0.8%–1%), and Caco-2/HT29-MTX (0.58%–1%) cell monolayers further verified the absorption of micelles and their subsequent transport; however, more TPGS micelles transported across cell monolayers than other groups. Moreover, the histological examination also confirmed that micelles entered the enterocytes and were transported to basolateral tissues and TPGS showed the stronger ability of penetration than other groups. Thus, these results are succinctly presenting the absorption of intact micelles in GIT confirmed by imaging evidence with prior leakage of the drug, uptake by enterocytes and the transport of micelles that survive the digestion by enterocytes and mainly by microfold cells in material nature dependent way with TPGS showing better results than other groups. In conclusion, these results identify the mechanism by which the gastrointestinal tract processes micelles and point to the likely use of this approach in the design of micelles-based therapies.     

微生物脂肽在气/液界面上的分子形态*

微生物脂肽是一类具有很强表面活性和生物特性的生物表面活性剂。脂肽分子由亲水的肽链和疏水的脂肪烃链两部分组成,由于其特殊的化学组成和两亲性分子结构,脂肽类生物表面活性剂在医药、食品、化妆品、环境修复和微生物采油等领域具有良好的应用潜力。表面活性素是一类典型的微生物脂肽化合物,这主要是因为它除了具有表面活性外,还具有抗菌、抗病毒等生物活性。表面活性和生物活性主要在界面处发生,并受到活性分子在亲水/疏水界面上的分子形态的影响。本文重点以表面活性素为评述对象,综述了近年来微生物脂肽在气/液界面上分子形态的研究进展。     

Transport of harman alkaloids across Caco-2 cell monolayers

This study examined the intestinal transport of five harman alkaloids using the Caco-2 cell monolayer as a model of the human intestinal mucosa. Transport parameters, permeability coefficients and percent transports, were calculated and compared under identical conditions with atenolol. Permeability coefficients were also compared with the reported values for model compounds like mannitol, propranolol and glucose. Sodium fluorescein was used as the marker for paracellular leakage. These alkaloids, in the concentration range of 250-500 microM, demonstrated substantial transport across the monolayer with moderate to high efflux rates and permeability coefficients. The transport was linear with time and was concentration dependent.