谷朊蛋白的改性及应用

近20年来,利用动植物等可再生资源代替当前广泛使用的石化材料成为热门研究方向,是消除污染、保护环境、实现绿色化学、推进人类社会与环境和谐发展的唯一途径.谷朊蛋白是谷类淀粉加工的副产物,是植物代谢产生的天然植物蛋白,一种生物可降解、可再生的天然高分子.由于其独特的粘弹性、延伸性、薄膜成型性和热凝固性等,越来越受到人们的重视,不仅拓宽了在食品工业中的应用领域,还可作为价格适宜、性能优良的高分子材料应用于其它领域.本文介绍了有关谷朊蛋白的组成、近年来国内外改性原理和方法,及其潜在的应用.     

肝素诱导人细胞型朊蛋白构象变化的光谱表征

粘多糖在朊病毒病中所发挥的作用目前仍存在争议.以肝素钠作为粘多糖的代表,通过共振光散射光谱、荧光光谱和圆二色光谱的变化研究了肝素钠与人重组细胞型朊蛋白(rhPrPC23-231)的相互作用.结果表明,肝素钠与朊蛋白相互作用后光散射和荧光信号均得到增强,并且使朊蛋白的荧光寿命有一定程度的延长.圆二色光谱表明肝素钠能诱导朊蛋白从富含α-螺旋的构象向富含β-折叠的构象转变.     

谷朊粉/淀粉/甘油混合体系的流变行为与力学性能

研究了甘油增塑谷朊粉/淀粉混合体系的动态流变行为与单轴拉伸力学性能,考察了淀粉与水含量的影响.研究结果表明,含水量10%的混合体系储能模量(G′)随淀粉含量增大而增大,并在100℃出现橡胶平台.增塑谷朊粉在30℃呈现凝胶特性,在80℃出现交联网络结构.淀粉粒子可与小麦蛋白质形成复杂相互作用,阻碍蛋白质链段运动,导致模量与强度增加,断裂伸长率降低.含水量为20%与25%时,水份在淀粉粒子与蛋白质网络间起稀释和润滑作用,拉伸强度与断裂伸长率随淀粉含量的增高而降低.     

麋鹿朊蛋白结构稳定性的分子动力学研究

朊蛋白病是一种致命且具有高度传染性的神经退行性疾病.糜鹿是目前已经报道的哺乳类动物中较易发生朊蛋白病的物种之一.作者使用分子动力学和操控式分子动力学模拟相结合的方法对糜鹿正常朊蛋白的结构稳定性进行了研究.发现了麋鹿朊蛋白结构中的不稳定结构域分布以及热动力学性质,揭示了糜鹿朊蛋白稳定性的分子结构基础以及力学特征.     

人类朊蛋白的动力学稳定性研究（英文）

朊蛋白病是一种能在人类或者动物之间传播的致命的神经退行性疾病.尤其是人类朊蛋白疾病在近几年蔓延迅速,已经威胁到人类的健康.在本文中,我们使用分子动力学(MD)和流体分子动力学(FMD)模拟相结合的方法研究了人类朊蛋白(hPrPc)的动力学稳定性.我们通过FMD模拟产生了两个典型的hPrPc的变性结构,并进一步研究了在自然状态下这两个变性结构重折叠的过程,从关键残基、二级结构、残基-残基相互作用图等方面详细讨论了hPrPc的解折叠和重折叠路径.研究发现hPrPc的三个α-螺旋结构组成了一个疏水核心,在蛋白质的解折叠和重折叠过程中发挥了重要的作用.刚性的疏水核心就像是脚手架一般为hPrPc的重折叠提供便利.在重折叠过程中,π-螺旋和310螺旋出现几率较高,并且β-折叠的延长也更多地出现在完全解折叠的hPrPc体系中.     

改性葡萄糖印染还原剂的制备及性能研究

以葡萄糖、戊二醛、焦亚硫酸钠为原料,通过羟甲基化和磺化反应制备出新型高效环保还原剂,优化了合成工艺,红外光谱表征了产品结构,对比了合成还原剂和保险粉的性能。通过优化实验确定了制备的最佳工艺:葡萄糖/戊二醛/焦亚硫酸钠的摩尔比为1∶3.5∶1.5、羟甲基化反应温度为70℃、羟甲基化反应时间为1.5 h、磺化反应温度为95℃、磺化反应时间为3 h,产品在30℃、还原剂质量浓度为5 g/L、NaOH质量浓度为15 g/L条件下5 min的还原电位为-933 mV。性能测试结果表明合成的还原剂在空气中保持稳定的时间以及其还原性能均优于市售的保险粉。     

兔子朊蛋白结构稳定性的分子动力学研究(英文)

朊蛋白病是一种能够对人类和动物带来致命影响,并具有高度传染性的神经退行性疾病.兔子是目前已经报道的哺乳类动物中对朊蛋白病免疫的少数几个物种之一.我们将分子动力学和操控式分子动力学模拟相结合,研究了兔子正常朊蛋白的结构稳定性;同时讨论了蛋白结构的收敛性及刚性分布,并揭示了兔子朊蛋白中关键二级结构的动力学以及受力各向异性特征,证实了兔子朊蛋白结构的稳定性特征.     

壳聚糖改性及用其整理纺织品抗菌性能的研究

用羟甲基化和醚化等方法制备了改性壳聚糖羟甲基壳聚糖和羟乙基乙基醚壳聚糖。在中性条件下它们溶解于水。实验显示，改性壳聚糖具有较好的抑菌作用和吸湿保湿性能。对织物进行的后整理实验发现，羟乙基乙基醚壳聚糖适用于对棉布的整理加工，羟甲基壳聚糖适用于对真丝绸的整理加工。经整理后的织物具有较好的抗菌性，且吸湿、透湿、染色性能较优。研究表明改性壳聚糖可作为优良的功能性天然“绿色”纺织品整理剂。     

过氧钒配合物抑制朊蛋白淀粉样肽的纤维形成

采用荧光光谱(FS)、核磁共振(NMR)、电喷雾离子化质谱(ESI-MS)和透射电镜(TEM)方法研究过氧钒配合物(NH₄)[VO(O₂)₂(bipy)]·4H₂O(1)和(NH₄)[VO(O₂)₂(phen)]·2H₂O(2)与朊蛋白淀粉样肽PrP106-126的突变体M109F肽的相互作用。结果表明,过氧钒配合物可直接与M109F肽结合,并通过甲硫氨酸112的氧化作用来达到对M109F肽聚集的抑制作用。与配合物2比较,配合物1显示出对M109F肽更好的抑制作用;过氧钒配合物1和2都可以有效地降低M109F肽诱导的细胞毒性。本工作为潜在金属药物用于神经退行性疾病的研究提供了基础数据。     

多金属氧化物立方纳米晶体的可控合成及其与朊蛋白的特异性相互作用

研究表明,在有机小分子二甲基甲酰胺（DMF）的调控作用下Keggin型多金属氧化物在水溶液中形成规则的纳米立方体,随温度改变该纳米立方体转变为空心立方结构．该多金属氧化物纳米立方体可以与朊蛋白（PrP^c）相互作用,产生显著的光散射信号增强,且增强程度在3．36-840ng·mL^-1范围内与朊蛋白浓度呈线性关系．     

Influence of Farming System and Forecrops of Spring Wheat on Protein Content in the Grain and the Physicochemical Properties of Unsonicated and Sonicated Gluten

The potential for enhancing the spring wheat protein content by different cultivation strategies was explored. The influence of ultrasound on the surface and rheological properties of wheat-gluten was also studied. Spring wheat was cultivated over the period of 2018–2020 using two farming systems (conventional and organic) and five forecrops (sugar beet, spring barley, red clover, winter wheat, or oat). The obtained gluten was sonicated using the ultrasonic scrubber. For all organically grown wheat, the protein content was higher than for the conventional one. There was no correlation between the rheological properties of gluten and the protein content in the grain. Gluten derived from organically grown wheat was more elastic than those derived from the conventional one. Sonication enhanced the elasticity of gluten. The sonication effect was influenced by the forecrops. The most elastic gluten after sonication was found for organic barley and sugar beet. The lowest values of tan (delta) were noted for conventional wheat and conventional oat. Cultivation in the monoculture gave gluten with a smaller susceptibility to increase elasticity after sonic treatment. Sonication promoted the cross-linking of protein molecules and induced a more hydrophobic character, which was confirmed by an increment in contact angles (CAs). Most of the organically grown wheat samples showed a lower CA than the conventional ones, which indicated a less hydrophobic character. The gluten surface became rougher with the sonication, regardless of the farming system and applied forecrops. Sonication treatment of gluten proteins rearranged the intermolecular linkages, especially disulfide and hydrophobic bonds, leading to changes in their surface morphology.     

荧光光度法测定纸中荧光增白剂VBL

采用荧光光度法测定纸中荧光增白剂VBL的含量。样品以pH 8的水为解析液,微波辅助萃取120s。VBL的质量浓度在2.00mg·L-1以内与其荧光强度呈线性关系,检出限(3s/k)为0.001mg·L-1。以学生作业纸样品为基体进行加标回收试验,所得回收率在84.7%~94.9%之间。对同一纸品平行测定5次,测定值的相对标准偏差为3.4%。     

马来海松酸酐的合成及其作为环氧树脂固化剂的研究

以松香酸和马来酸酐为原料,通过D-A反应合成了高纯度的马来海松酸酐,用IR、NMR、元素分析等对其进行了结构表征.在此基础上,分别用马来海松酸酐和偏苯三酸酐对环氧树脂DER662E进行固化,并用DMA、力学性能测试仪、TGA等对比研究了固化后环氧树脂的模量、玻璃化转变温度、拉伸强度等力学性能和耐热性能.探索了生物基马来...     

Modification of Kagan's amide for improved activity as Chiral Solvating Agent in enantiodiscrimination during NMR analysis

A modification is proposed in Kagan's amide in order to improve its ability to offer stronger hydrogen bonding and hence better ability to bind with substrates. Introduction of chlorine in the amide aromatic ring along with the two nitro groups, increases the acidic character of amide hydrogen and makes the hydrogen bond stronger, the concept is tested by making three derivatives of Kagan's amide and the effect is confirmed by nmr analysis. The modified chlorinated Kagan's amides were then tested as chiral solvating agents for detection of optical purity of several types of substrates where the supramolecular recognition is measured by in situ nmr analysis. Several guest molecules such as amide, sulfoxide, epoxy-keto, hydroxy acid, diacid and phosphoric acid were scanned for this study and its efficiency is further established by comparison with samples of known optical purity.     

硅烷偶联剂制备及对磷灰石-硅灰石生物玻璃陶瓷的表面改性

采用谷氨酸与硅烷偶联剂(KH-792)缩合反应,制备出一种含酰胺基的硅烷偶联剂,利用其与材料之间的化学结合,将谷氨酸共价固定至磷灰石-硅灰石生物玻璃陶瓷表面,实现表面改性。将改性后的磷灰石-硅灰石生物玻璃陶瓷与人骨肉瘤细胞MG63共培养,评价其体外细胞生物相容性。应用FTIR、SEM、XPS等测试技术分别对合成的偶联剂、改性后的陶瓷材料进行结构、表面形貌及细胞生长情况的表征,结果表明:谷氨酸与KH-792的反应产物有酰胺基生成;含酰胺基的硅烷偶联剂能对磷灰石-硅灰石生物玻璃陶瓷表面进行有效改性;共培养3 d后细胞在材料材料表面大量贴附,MTT实验也证明增殖良好,即含酰胺基的硅烷偶联剂能改善磷灰石-硅灰石生物玻璃陶瓷的体外细胞生物相容性。     

段式正交信号校正方法及在小麦近红外光谱数据分析中的应用

针对光谱数据峰宽、局部效应显著、含有噪音、变量个数多及彼此间常存在严重的复共线性等问题,改进和设计一种光谱数据局部校正方法:基于窗口平滑的段式正交信号校正方法,并将之结合偏最小二乘回归,以实现光谱数据的预处理及定量分析。通过NIPALS算法初始化将滤去的正交成分,以近邻分段方式进行逐个波长点的正交信号校正。而后将去噪后的光谱矩阵作为新的自变量阵,通过偏最小二乘回归构建其与性质参变量间的校正模型。通过小麦近红外漫反射光谱数据的应用实验结果表明,本方法正交成分估计稳定,去噪明显,模型的预报性能优于其它方法,PLS成分数减少,模型更加简洁。     

Synthesis and Application of Poly(diallyldimethylammonium tribromide)as a Novel Polymeric Brominating Agent

In this study, the synthesis and applications of a new supported tribromide reagent based on poly(diallyldimethylammonium chloride) is reported. This supported tribromide is used in α‐bromoacetalization of ketones, bromination of alkenes and regioselective bromination of activated aromatic compounds. This method is mild and no Br₂ and HBr were used. Other advantages of this reagent are stability, high efficiency, simple filtera‐ bility and reusability.     

蜂蜜中糖的薄层展开剂的研究与应用

 建立了蜂蜜中糖的薄层色谱分析法。色谱条件:冰醋酸-氯仿-95%乙醇(体积比为21∶23∶15)为流动相,固定相为涂布于薄层板上的硅胶G-0.2 mol/L 醋酸钠溶液。对多个蜂蜜样品和果糖、葡萄糖、蔗糖标准品进行上行展开,并用苯胺-二苯胺-磷酸显色剂显色。结果表明:真蜜图谱上出现5个色斑,其中果糖呈火红色,葡萄糖呈纯蓝色,蔗糖呈紫色,麦芽糖和多聚葡萄糖呈蓝色。将样品色斑的颜色、深浅度和Rf值与标准糖进行比较,能判断蜂蜜中的还原糖总含量和蔗糖含量,同时也能了解其他少量多糖的存在情况。通过与真蜜图谱比较,     

Effects of Physical and Chemical Factors on the Structure of Gluten,Gliadins and Glutenins as Studied with Spectroscopic Methods

This review presents applications of spectroscopic methods, infrared and Raman spectroscopies in the studies of the structure of gluten network and gluten proteins (gliadins and glutenins). Both methods provide complimentary information on the secondary and tertiary structure of the proteins including analysis of amide I and III bands, conformation of disulphide bridges, behaviour of tyrosine and tryptophan residues, and water populations. Changes in the gluten structure can be studied as an effect of dough mixing in different conditions (e.g., hydration level, temperature), dough freezing and frozen storage as well as addition of different compounds to the dough (e.g., dough improvers, dietary fibre preparations, polysaccharides and polyphenols). Additionally, effect of above mentioned factors can be determined in a common wheat dough, model dough (prepared from reconstituted flour containing only wheat starch and wheat gluten), gluten dough (lack of starch), and in gliadins and glutenins. The samples were studied in the hydrated state, in the form of powder, film or in solution. Analysis of the studies presented in this review indicates that an adequate amount of water is a critical factor affecting gluten structure.