Shape and structure controlling of calcium oxalate crystals by a combination of additives in the process of biomineralization

The origin of complex hierarchical superstructures of biomaterials and their unique self-assembly mechanisms of formation are important in biological systems and have attracted considerable attention. In the present study, we investigated the morphological changes of calcium oxalate (CaO_x) crystals induced by additives including chiral aspartic acid, sodium citrate, Mg²⁺, casein and combinations of these molecules. The morphology and structure of CaO_x were identified with the use of various techniques. The morphogenesis of CaO_x crystals were significantly affected by chiral aspartic acid, sodium citrate or Mg²⁺. However, they only formed calcium oxalate monohydrate (COM). It was observed that the chiral aspartic acid, sodium citrate and casein adhered to the surface of the crystals. The adherence of Mg²⁺ to crystals was not evident. Casein significantly affected the formation of COM and calcium oxalate dihydrate (COD). The ratio of different CaO_x crystal forms is associated with the casein concentration. In combination with Mg²⁺ or citrate ions, casein showed improved formation of COD. The present study mimics biomineralization with a simple chemical approach and provides insight into the complicated system of CaO_x biomineralization as well as facilitates the understanding of urinary stone treatment.

Combination of casein and small molecules regulates morphogenesis of calcium oxalate crystals.     

Insights into Ag(i)-catalyzed addition reactions of amino alcohols to electron-deficient olefins: competing mechanisms,role of catalyst,and origin of chemoselectivity

The competing mechanisms of Ag(i)-catalyzed chemoselective addition reactions of amino alcohols and electron-deficient olefins leading to the O-adduct or N-adduct products were systematically studied with density functional theory methods. Calculations indicate that the AgHMDS/dppe versus AgOAc/dppe catalytic systems can play different roles and thereby generate two different products. The AgHMDS/dppe system works as a Brønsted base to deprotonate the amino alcohol OH to form the Ag–O bond, which leads to formation of the O-adduct. In contrast, the AgOAc/dppe system mainly acts as a Lewis acid to coordinate with O and N atoms of the amino alcohol, but it cannot act as the Brønsted base to further activate the OH group because of its weaker basicity. Therefore, the AgOAc/dppe catalyzed reaction has a mechanism that is similar to the non-catalyzed reaction, and generates the same N-adduct. The obtained insights will be important for rational design of the various kinds of cooperatively catalyzed chemoselective addition reactions, including the use of the less nucleophilic hydroxyl groups of unprotected amino alcohols.

The origin of the chemoselectivities of Ag(i)-catalyzed addition reactions of amino alcohols to olefin has been predicted for the first time.     

本草基因组学的学科建设现状与展望

本草基因组学是中药学与基因组学的交叉学科,是涵盖药用生物多组学研究和中药与人体相互多组学研究的综合性学科。在药用模式生物、中药合成生物学、中药分子鉴定和药用植物分子育种、药物体内过程组学、中药道地性和药性研究等领域得到了广泛应用,取得了一批标志性成果。随着《中华人民共和国中医药法》《中医药发展战略规划纲要(2016—2030年)》等重要文件的发布,中医药产业进入了全新的、高水平的发展机遇期,复合创新型研究人才的培养是中医药产业发展及医药专业高校教学改革面临的关键问题,该学科的建立对于中医药现代化发展尤为重要,已有多所高等院校开设《本草基因组学》课程,初步形成了特色鲜明的本草基因组学人才培养体系。该文从本草基因组学研究进展、教学开展情况、教材编写背景、主要内容及关键技术、学科特色、学科建设展望方面进行阐述,为本草基因组学的学科建设、人才培养和科学研究提供理论依据和方法学支撑。     

药用植物三尖杉及其同属易混物种的DNA条形码鉴定研究

目的：探索建立适用于鉴定药用植物三尖杉及其同属易混物种的DNA条形码鉴定体系,以保障其用药安全。方法：提取三尖杉属3个物种（三尖杉、粗榧和篦子三尖杉）共22份样本的基因组DNA、扩增ITS2和psbA-trnH 序列并测序,通过CodonCode Aligner V4.2对测序峰图进行校对拼接。应用MEGA 5.1计算种内和种间Kimura 2-Paramter（K2P）遗传距离,构建邻接（Neighbor-Joining, NJ）系统聚类树。结果：基于ITS2序列分析,三尖杉的种内最大遗传距离小于种间最小遗传距离;基于psbA-trnH 序列分析,三尖杉的种内和种间遗传距离有重合。结论：应用ITS2序列,可以实现对三尖杉及其易混物种的鉴别,为三尖杉药材的安全使用提供鉴定依据。     

DNA条形码鉴定与功效组分测定在紫草质量评价中的应用

目的:利用DNA条形码技术对中药紫草进行基源鉴定,并建立紫草的功效多组分含量测定方法,为全面评价紫草药材质量提供依据。方法:对不同产地紫草进行DNA条形码基原鉴定;采用高效液相色谱法测定紫草中萘醌类成分与含量,Thermo BDS Hypersil C_(18)色谱柱(4.6 mm×250 mm,5μm),流动相0.2%冰乙酸-乙腈梯度洗脱,流速0.8 m L·min~(-1),检测波长275 nm,柱温35℃。结果:经DNA条形码鉴定了11批药材,均为紫草科植物新疆紫草Arnebia euchroma的干燥根;测定了11批新疆紫草的8种萘醌类功效组分含量,各组分均显示良好分离;不同成分在线性范围内线性关系良好,平均回收率在95.26%~101.40%,RSD均在0.7%~1.8%(n=6)。结论:DNA条形码鉴定确保了新疆紫草药材基源的准确性,组分含量测定方法准确可靠、重复性好,二者结合可作为紫草的质量控制方法。     

无公害辛夷栽培技术探讨

辛夷是中国传统药材,来源于木兰科望春花Magnolia biondii Pamp.、玉兰Magnolia denudata Desr.或武当玉兰Magnolia sprengeri Pamp.的干燥花蕾。辛夷主要具有发散风寒、宣通鼻窍之效,其野生资源少,野生资源少,市场的需求量随着人们生活水平的提高越来越大,种植出优质无公害辛夷栽培品已成为重要研发目标。因此,无公害辛夷的栽培将是未来辛夷产业发展的主流。本文从辛夷产地生态适宜性栽培用地的区划出发,根据栽培环境要求、科学种植技术、施肥规范、病虫害防治、采收加工及质量标准等内容制定了辛夷无公害农田栽培技术体系,为辛夷的栽培生产提供科学性的指导。     

A conductive sodium alginate and carboxymethyl chitosan hydrogel doped with polypyrrole for peripheral nerve regeneration

Polymer materials with electrically conductive properties have good applications in their respective fields because of their special properties. However, they usually exhibited poor mechanical properties and biocompatibility. In this work, we present a simple approach to prepare conductive sodium alginate (SA) and carboxymethyl chitosan (CMCS) polymer hydrogels (SA/CMCS/PPy) that can provide sufficient help for peripheral nerve regeneration. SA/CMCS hydrogel was cross-linked by calcium ions provided by the sustained release system consisting of d-glucono-δ-lactone (GDL) and superfine calcium carbonate (CaCO₃), and the conductivity of the hydrogel was provided by doped with polypyrrole (PPy). Gelation time, swelling ratio, porosity and Young''s modulus of the conductive SA/CMCS/PPy hydrogel were adjusted by polypyrrole content, and the conductivity of it was within 2.41 × 10⁻⁵ to 8.03 × 10⁻³ S cm⁻¹. The advantages of conductive hydrogels in cell growth were verified by controlling electrical stimulation of cell experiments, and the hydrogels were also used as a filling material for the nerve conduit in animal experiments. The SA/CMCS/PPy conductive hydrogel showed good biocompatibility and repair features as a bioactive biomaterial, we expect this conductive hydrogel will have a good potential in the neural tissue engineering.

Polymer materials with electrically conductive properties have good applications in their respective fields because of their special properties.