富硒香菇中微量元素硒的含量测定

以香菇为载体,通过在培养基中加入一定质量浓度的复合硒溶液进行富硒栽培,获得了富硒香菇,并成功提取出香菇硒多糖,应用2,3-二氨基萘荧光分光光度法测定了富硒香菇中的硒含量,方法简单,结果可靠。     

高效液相色谱-原子荧光光谱联用技术测定富硒鸡蛋中的硒形态

为监测市场上富硒鸡蛋中蛋清及蛋黄中硒形态的种类及分布规律,优化建立了一种高效液相色谱-氢化物发生-原子荧光光谱联用技术测定富硒鸡蛋蛋清及蛋黄粉中硒形态的方法。随机选取富硒鸡蛋样品,进行蛋清蛋黄分离、冷冻干燥及蛋黄脱脂处理,处理后样品经Tris-HCl缓冲液（5 mmol/L, pH=7.5）55 oC恒温振荡、酶解提取,高速离心机（10000 r/min）离心10 min,上清液过0.22 μm有机滤膜后采用高效液相色谱-氢化物发生-原子荧光光谱联用技术进行测定,外标法定量。结果表明,该方法能在11 分钟内实现5种硒形态的基线分离,且各种硒形态的线性相关系数(r)均大于0.9994,其检出限在0.5-3.0 μg/L之间,回收率在81.6%~110.4%之间,可以满足检测需求,按照该实验方法测定市场上富硒鸡蛋中的硒形态,方法灵敏度高、准确性好,且测得的富硒鸡蛋蛋清样品中硒形态主要成分为硒代蛋氨酸,而蛋黄样品主要成分为硒代半胱氨酸,还有少量的硒代蛋氨酸,同时,一些鸡蛋还含有极少量的亚硒酸根,但蛋清及蛋黄中硒代氨基酸的含量总和占总硒含量的83.3-98.4%,适用于富硒鸡蛋中的硒形态提取。由此可见,市场上富硒鸡蛋中的硒主要以硒代氨基酸的形式存在,比较适合日常补硒,且该方法可以对市场上富硒食品起到一定监测作用。     

隆回富硒区山银花不同花期硒分布规律研究

通过分析山银花不同花期硒含量,探讨了山银花中硒的积蓄规律与土壤硒之间的关系。选择湖南省隆回县小沙江地区加油站北和岩背村两处土壤硒含量分别为0.968 mg/kg和0.837mg/kg的山地,种植灰毡毛忍冬的两个不同品种:白云一号和金蕾一号,在花期内连续采收绿蕾期、白蕾期、白花期和金花期样本,脱水后,用电化学法测定硒含量。结果表明,白云一号和金蕾一号的绿蕾期、白蕾期、白花期和金花期硒平均含量分别为0.111、0.191、0.191、0.295 mg/kg和0.146、0.260、0.272、0.363 mg/kg,金蕾一号的硒积蓄能力优于白云一号。结论是富硒区山银花中硒的积蓄量与品种、花期密切相关,但与土壤中硒含量无明显相关性。     

中国富硒食品的生产现状及趋势

对硒的生物学作用和目前已经开发的富硒食品(富硒西瓜、富硒灵芝、富硒茶叶、富硒牛奶、富硒猪肉和富硒鸡蛋等)进行了概述。当前富硒食品的技术含量大多偏低,技术水平有待提高;价廉物美的富硒食品受市场欢迎,科学论证富硒食品的转化机制是今后科研的一个方向。     

富硒米对大鼠细胞免疫功能影响的实验研究

为探讨富硒米的剂量对大鼠免疫功能的影响和富硒米用于保健食疗提供有意义的实验依据,选用纯种ＳＤ大鼠４０只,随机分为高中低三个剂量组,分别给予富硒米和常规饲料喂养３０ｄ,称重,取血做Ｔ淋巴细胞转化和自然杀伤细胞活性试验。结果表明：①富硒米能显著提高大鼠Ｔ淋巴细胞转化率,中剂量组与对照组比较有显著性差异（ｔ检验,Ｐ〈０．０５）。②富硒米大鼠ＮＫ活性对照比较,没有显著性差异 。结论是富硒米能显著提高大鼠Ｔ     

富硒螺旋藻光谱特性及其含硒蛋白质组分析

以富硒螺旋藻( Selenium enriched spirulina platensis, Se-SP)为材料,采用红外、紫外-可见吸收光谱分析Se-SP的光谱特征,并利用二维电泳技术(Two-dimensional electrophoresis,2DE)分离、飞行时间质谱(Matrix assisted laser desorption ionization time of flight, MALDI-TOF)鉴定和电感耦合等离子体质谱( Inductively coupled plasma mass spectrometry, ICP-MS)检测硒含量,对Se-SP蛋白质组及其含硒蛋白质分布进行初步鉴定和分析。结果显示,硒对螺旋藻蛋白质组中多种蛋白质表达有一定影响,观察到对捕光色素蛋白如藻蓝蛋白( Phycocya-nin, PC)、别藻蓝蛋白( Allophycocyanin , APC)和 Robisco大亚基及超氧化物歧化酶( Superoxide Dismutase, SOD)等蛋白质具有明显上调作用。硒在Se-SP蛋白质组中存在较为普遍,但分布相对集中在pH 4~7、分子质量14.4~43 kDa的蛋白质中。硒在藻体特定蛋白质中的存在形式还有待深入研究和鉴定。     

AFS和GFAAS法测定富硒粮食中硒含量的比较研究

富硒粮食是产量较大的富硒农产品,受到消费者的喜好。通过原子荧光光谱法(AFS)和石墨炉原子吸收光谱法（GFAAS）分别测定粮食中硒含量。比较这2种常用的硒测定方法,分析影响结果准确度的主要因素、方法的特点及适用条件,为富硒粮食生产监管选择适合分析方法提供参考依据。AFS法的方法检出限为0.2 ug/L,其灵敏度相对较高;GFAAS法的方法检出限为0.6 ug/L,其灵敏度相对较低,但操作较为简捷快速。分别采用这2种方法测定对国家标准物质GBW10045大米中硒含量进行测定,结果准确,这2种方法均适用于富硒粮食的硒含量测定工作。     

高效液相色谱-电感耦合等离子体质谱（HPLC-ICP-MS）联用测定富硒小麦中硒代氨基酸

为科学补硒和促进富硒小麦的种植推广,建立了高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)检测富硒小麦中硒代氨基酸的方法。用蛋白酶XIV辅助微波振荡提取富硒小麦中硒代氨基酸,采用C18 分离柱分离,以30.0mmol/L磷酸氢二铵+1.0%甲醇+2.0mmol/L四丁基溴化铵溶液(pH=6.5)为流动相,能在10min内实现5种硒代氨基酸的分离。在高能氦气模式（HEHe）下,用78Se的色谱峰积分面积作为定量依据,5种硒代氨基酸在1.0～200.0μg/L范围内线性相关性良好,检出限在 0.11~0.29μg/L之间。以富硒小麦为基体进行加标回收试验,除硒代胱氨酸（SeCys2）可能不稳定,易分解造成回收率偏低外,其他4种硒代氨基酸的加标回收率在92.34～102.46%之间,相对标准偏差为 1.6 %~4.2 %（n=7）。用该方法测定了农业科技工作者种植推广的富硒小麦,结果发现小麦中的硒赋存形态多为硒代蛋氨酸（SeMet）,此外,小麦中还含有少量硒代胱氨酸（SeCys2）、硒代半胱氨酸（SeCys）、甲基硒代半胱氨酸（MeSeCys）和硒代乙硫氨酸（SeEt)。该方法具有良好的精密度和准确度,适用于富硒小麦中硒代氨基酸的形态分析。     

高效液相色谱与电感耦合等离子体质谱联用技术用于胁迫富硒海带硒形态研究

通过对海带胁迫富硒培养, 研究了海带对硒的富集总量及硒化学形态转变. 建立了反相离子对缓冲盐等3个色谱系统的高效液相色谱与电感耦合等离子体质谱联用(RP-HPLC-ICP-MS)技术测定亚硒酸钠、硒甲基半胱氨酸(MeSeCys)、硒代蛋氨酸(SeMet)三种硒形态. 采用3种提取溶剂, 超声提取缩短提取时间, 分离检测富硒海带的主要硒形态为亚硒酸钠、硒甲基半胱氨酸和硒代蛋氨酸.     

富硒灵芝中一种新含硒蛋白的纯化、性质及其自由基清除活性研究

通过硫酸铵沉淀、离子交换层析和分子排阻层析等方法, 从富硒灵芝中获得了一种新的含硒蛋白, 命名为Se-GL-P, 并研究了此蛋白的性质、抗氧化活性与其硒含量间的关系. 结果表明, 此蛋白的分子量为36600, 分子中约含有19.8%的糖链, N端的氨基酸残基序列为DINGGGATLPQKLYLTPDVL, 属于DING蛋白家族. 硒含量为4.87 mg/g, 具有较高的羟自由基和超氧自由基清除活性. 研究发现, Se-GL-P的抗氧化活性的提高与其中硒含量的提高相关.     

香菇多糖的成分及其分子量研究

从香菇子实体中用0.9%NaCl水溶液、85%乙醇、热水、1%草酸铵、5%NaOH/0.05%NaBH₄和2%NaOH/2%尿素分别提取出四种杂多糖(L-FⅠ-L-FⅣn)和两种葡聚糖(L-FⅤ和L-FⅥn).红外光谱和高效液相色谱分析结果表明杂多糖主要由葡萄糖、葡萄糖醛酸、木糖、甘露糖、半乳糖和鼠李糖组成,而且按照分离过程的进行多糖中葡萄糖含量递增.由光散射和膜渗透压法研究了多糖的重均分子量Mw、均方根旋转半径2>^1/2、第二维利系数A₂及数均分子量M_n.L-FⅡ、L-FⅢ、L-FⅤ及L-FⅥn的M_w值依次为19.7×10⁴、192.3×10⁴、136.4×10⁴和136.7×10⁴,它们的多分散系数-Mw/-Mn在3～5范围.     

Influence of Microwave Blanching on Arsenic Speciation and Bioaccessibility in Lentinus Edodes

Humans are exposed to arsenic by inhalation and ingestion and are therefore may be affected by its toxicity. Arsenic may enter the human body by inhalation and ingestion. Cooking may alter the contents and chemical forms of arsenic. The determination of arsenic species in Lentinus edodes after microwave blanching was performed by high-performance liquid chromatography–inductively coupled plasma–mass spectrometry. Using a physiologically based extraction, the bioaccessibility of arsenic species in raw L. edodes and microwave blanching treated L. edodes were determined after the simulated gastrointestinal digestion. The arsenate (As^V), arsenite (As^III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine, and arsenocholine did not undergo decomposition and transformation in this study. Furthermore, the total contents of arsenic in L. edodes samples were in the range of 0.1378?±?0.0044–0.2347?±?0.0144?mg/kg. Approximately 3.38–43.27% were released from samples into the blanching water after various microwave blanching treatments. The oxidation of As^III and demethylation of DMA and MMA were observed in L. edodes during digestion, increasing the likelihood of arsenic toxicity in the liver. The health risk for arsenic in L. edodes was decreased after microwave blanching because the potentially available arsenic in microwave blanching treatments L. edodes samples (83.78?±?0.9103%) were lower than those in raw L. edodes samples (88.33?±?0.7983%). L. edodes subjected to microwave blanching prior to consumption significantly decreased the total arsenic content and the risk of arsenic exposure to consumers (p?相似文献   

A green and efficient protocol for large‐scale production of glycyrrhizic acid from licorice roots by combination of polyamide and macroporous resin adsorbent chromatography

A green and efficient method for large‐scale preparation of glycyrrhizic acid from licorice roots was developed by combination of polyamide and macroporous resin. The entire preparation procedure consisted of two simple separation steps. The first step is to use polyamide resin to remove licorice flavoniods from the licorice crude extract. Subsequently, various macroporous resins were tried to purify glycyrrhizic acid, and HPD‐400 showed the most suitable adsorption and desorption properties. Under the optimized conditions, a large‐scale preparation of glycyrrhizic acid from licorice roots was carried out. A 20 kg raw material produced 0.43 kg of glycyrrhizic acid using green aqueous ethanol as the solvent. The purity of glycyrrhizic acid was increased from 11.40 to 88.95% with a recovery of 76.53%. The proposed method may be also extended to produce large‐scale other triterpenoid saponins from herbal materials.     

用高效液相色谱研究头孢菌素类药物热力学函数及其定量构效关系

本文实验表明反相高效液相色谱流动相组成与头孢菌素容量因子成线性关系,并测定了头孢菌素的过量热力学函数△(?)～·,证明头孢菌素类药物的生物活性与△(?)～·存在定量构效关系.从而提出△(?)～·和△(?)～·分别是研究药物定量构效关系和药物生化过程的重要参数之一.     

A Quantum Chemistry Study of Inhibition Properties of Imidazole and Its Derivatives on Iron Surface Corrosion

The geometries of imidazole and its derivatives were respectively optimized by using ab initio method, and the molecular orbital energy levels and the charge densities were obtained for their optimum geometries. The frontier orbital energy levels, and the net charges of N (1) atom and the imidazole ring of those molecules were obtained with ab initio and SCC-DV-Xα methods. It was found that the inhibition properties of those compounds change with the highest occupied molecular orbital energy levels, and the net charges of N (1) atom. We took four iron atoms on the crystal plane (100) of α-iron as the surface which was used to study the adsorption towards the inhibitors. The adsorption models of the inhibitor to be adsorbed on the Fe-cluster surface were optimized with SCC-DV-Xα method. It turns out that the most favorable model is that the inhibitor molecule is adsorbed on the Fe-cluster surface in an inclined state. The calculation shows that the stabilization energies of the systems are well correlated with the inhibition efficiencies.     

稀土掺杂TiO_2光催化剂的制备及产氢性能研究

采用溶胶-凝胶法制备了稀土掺杂的系列光催化剂RE/TiO2(La/TiO2,Eu/TiO2,Y/TiO2,Pr/TiO2,Nd/TiO2,Sm/TiO2,Gd/TiO2),XRD晶相结构表征分析表明稀土离子的掺杂有效抑制了TiO2晶粒的增长。分别考察了不同酸、醇为牺牲剂时RE/TiO2对光催化产氢性能的影响。实验结果表明:以乙醇为牺牲剂时,稀土的掺杂均提高了光催化产氢性能;以乙酸为牺牲剂时,只有铕和镧的掺杂提高了光催化活性。以La/TiO2为光催化剂,甲醇、乙醇和正丙醇为牺牲剂,光催化产氢活性顺序为:乙醇甲醇正丙醇;以Eu/TiO2为光催化剂,以甲酸、乙酸和丙酸为牺牲剂,光催化产氢活性依次为:甲酸丙酸乙酸;因此,牺牲剂的选择对光催化产氢活性有重要的影响。     

手性氨基酸的制备及生物活性研究进展

综述了近年来手性氨基酸的制备方法及其生物活性，包括化学拆分法、不对称合成法、结晶法、微生物法、酶法、配位萃取法、膜拆分法以及色谱法等制备方法，还介绍了手性氨基酸作为手性药物的生物活性作用，并对其研究的前景进行了展望。参考文献42篇。     

铷的生物必需性及人体健康效应

综述了铷的生物必需性及其对人体的健康效应,包括：铷的生物学研究简史,铷的营养必需性,铷的生理功能和生物学作用,人体的铷摄入量。参考文献45篇。     

硝基苯甲酸与氨基苯甲酸六种 异构体的HPLC分离研究

采用Kromasil C     

A Review on Preparation of Betulinic Acid and Its Biological Activities

Betulinic acid, a pentacyclic triterpene, is distributed in a variety of plants, such as birch, eucalyptus and plane trees. It shows a wide spectrum of biological and pharmacological properties, such as anti-inflammatory, antibacterial, antiviral, antidiabetic, antimalarial, anti-HIV and antitumor effects. Among them, the antitumor activity of betulinic acid has been extensively studied. However, obtaining betulinic acid from natural resources can no longer meet the needs of medicine and nutrition, so methods such as chemical synthesis and microbial biotransformation have also been used to prepare betulinic acid. At the same time, with the development of synthetic biology and genetic engineering, and the elucidation of the biosynthetic pathways of terpenoid, the biosynthesis of betulinic acid has also been extensively researched. This article reviews the preparation of betulinic acid and its pharmacological activities, in order to provide a reference for the research and utilization of betulinic acid.