RAFT聚合合成一种即含甲酰基又含手性β-蒎烯单元聚合物

设计并合成了一种新型含甲酰基同时又含β-蒎烯单元的新单体2-β-蒎氧基-5-乙烯基苯甲醛(POVB),选择苯基双硫代乙酸1-苯基乙酯(PEPDA)为RAFT试剂、以AIBN为引发剂、在60℃下THF中实现了POVB的"活性"/可控RAFT自由基聚合.单体浓度半对数ln([M]0/[M])与聚合时间符合线性关系,聚合过程呈现一级动力学特征;聚合物分子量(Mn)随单体转化率几乎线性增加,而且整个反应过程中分子量分布(Mw/Mn1.2)保持在较窄的范围.1H-NMR的分析进一步证实了聚合物链的末端精细结构.此外,CD谱结果表明手性单元β-蒎烯基能赋予聚合物以光学活性.     

Utility of porous graphitic carbon stationary phase in quantitative liquid chromatography/tandem mass spectrometry bioanalysis: quantitation of diastereomers in plasma

A major challenge in selecting an appropriate stationary phase for diastereomeric separation is that it is difficult to predict which of the commercially available stationary phases could achieve the required liquid chromatographic (LC) separation. This work describes the selection and evaluation of a porous graphitic carbon (PGC) column coupled with tandem mass spectrometry (MS/MS) for the simultaneous quantitation of an experimental drug candidate (I), its two diastereomeric metabolites (II and III), and its demethylated metabolite (IV) in rat plasma. In addition, we investigated the PGC column for the separation of another drug candidate (VI), its two diastereomeric metabolites (VII and VIII) and its ketone metabolite (IX). The PGC column showed excellent chromatographic resolution for the two diastereomers II and III, as well as for VII and VIII. In contrast, the required resolution for the diastereomers II and III could not be achieved using silica-bonded C(18), C(30), phenyl, perfluorinated, polar embedded and polar end-capped phases. The PGC column showed ruggedness with excellent reproducibility of retention times, peak symmetry and response over a period of more than 400 injections of a plasma acetonitrile-precipitation extract. Excellent accuracy and precision were achieved, with accuracy of 94-108% and intra- and inter-run precision within 9%. This work indicates that PGC is a valuable addition to the repertoire of LC columns used for quantitative LC/MS/MS bioanalysis, especially where the separation and quantitation of diastereomeric analytes is involved.     

Quantitation of a PEGylated protein in monkey serum by UHPLC-HRMS using a surrogate disulfide-containing peptide: A new approach to bioanalysis and in vivo stability evaluation of disulfide-rich protein therapeutics

To quantify a therapeutic PEGylated protein in monkey serum as well as to monitor its potential in vivo instability and methionine oxidation, a novel ultra high performance liquid chromatography-high resolution mass spectrometric (UHPLC-HRMS) assay was developed using a surrogate disulfide-containing peptide, DCP(SS), and a confirmatory peptide, CP, a disulfide-free peptide. DCP(SS) was obtained by eliminating the step of reduction/alkylation before trypsin digestion. It contains an intact disulfide linkage between two peptide sequences that are essential for drug function but susceptible to potential in vivo cleavages. HRMS-based single ion monitoring (SIM) on a Q Exactive™ mass spectrometer was employed to improve assay specificity and sensitivity for DCP(SS) due to its poor fragmentation and low sensitivity with SRM detection. The assay has been validated for the protein drug in monkey serum using both surrogate peptides with excellent accuracy (within ±4.4%Dev) and precision (within 7.5%CV) with a lower limit of quantitation (LLOQ) at 10 ng mL⁻¹. The protein concentrations in monkey serum obtained from the DCP(SS)-based assay not only provided important pharmacokinetic parameters, but also confirmed in vivo stability of the peptide regions of interest by comparing drug concentrations with those obtained from the CP-based assay or from a ligand-binding assay (LBA). Furthermore, UHPLC-HRMS allowed simultaneous monitoring of the oxidized forms of both surrogate peptides to evaluate potential ex vivo/in vivo oxidation of one methionine present in each of both surrogate peptides. To the best of our knowledge, this is the first report of using a surrogate disulfide-containing peptide for LC-MS bioanalysis of a therapeutic protein.     

不同细胞质雄性不育小麦阳离子过氧化物酶和IAA-氧化酶活性的研究

选用Ｃ－型、Ｍ－型、Ｍｔ２－型、Ｇ－型４个不同类型的细胞质雄性不育（ＣｙｔｏｐｌａｓｍｉｃＭａｌｅＳｔｅｒｉｌｉｔｙ，ＣＭＳ）小麦为材料，以其保持系中国春作对照，用低ｐＨ值（ｐＨ４．６）提取酶液，对分蘖期、拔节期、孕穗期和抽穗期叶、穗和花药中的阳离子过氧化物酶和ＩＡＡ－氧化酶活性进行了研究．结果表明：分蘖期和拔节期不育系叶中阳离子过氧化物酶和ＩＡＡ－氧化酶活性都比保持系略低；抽穗期叶、穗和花药中不育系两种酶的活性都比保持系高．故认为，小麦植株随着发育进程，其体内尤其是穗和花药中阳离子过氧化物酶和ＩＡＡ－氧化酶活性增强，导致ＩＡＡ亏缺，引起雄性不育的发生     

细胞质雄性不育小麦抽穗期阳离子过氧化物酶同工酶的研究

选用Ｃ－型、Ｇ－型、Ｍ－型、Ｍｔ２－型４种细胞质类型的７个不育系小麦为材料，以其保持系中国春作对照，用低ｐＨ值（ｐＨ４．６）提取酶液，采用正极和负极向垂直板聚丙烯酸胺凝胶电泳，对抽穗期时、穗和花药的阳离子过氧化物酶同工酶进行了研究．结果表明：花药中不育系和保持系之间无论是正极向还是负极向的过氧化物酶差异均显著．负极向的过氧化物酶不育系比保持系多了两条带且酶带显色更深，反映其酶活性更强；正极向的过氧化物酶中，不育系也比保持系多了两条带，但没有保持系特有的４条酶带（Ａ７～Ａ１０），并且快带也只有一条．花药中阳离子过氧化物酶同工酶谱带数增多，活性增强，可能是小麦雄性不育发生的原因之一．     

（无芒山羊草）中国春等小麦雄性不育系小孢子败育及育性恢复的初步研究

研究了（无芒山羊草）中国春、（尾状山羊草）中国春和（拟斯卑尔脱山羊草）中国春三种小麦细胞质雄性不育系（ｃｖｔｏｐｌａｓｍｉｃｍａｌｅｓｔｅｒｉｌｅｌｉｎｅ，ＣＭＳ）小孢子败育特点及育性恢复特性，结果表明：１．（无芒山羊草）中国春ＣＭＳ小孢子败育主要发生在单核晚期和二核期，以园败为主，园败频率为７５．９％；２·（尾状山羊单）中国春ＣＭＳ和（拟斯卑尔脱山羊草）中国春ＣＭＳ小孢子败育主要发生在单核晚期，以典败为主，典败频率分别为８０．５％和９２．５％；３．上述三种小麦ＣＭＳ易恢性不同，其中（拟斯卑尔脱山羊草）中国春ＣＭＳ易恢性相对较好，而（无芒山羊草）中国春ＣＭＳ相对较差．在测交试验中，三种ＣＭＳ都找到了育性可完全恢复的恢复系．拟斯卑尔脱山羊草细胞质和尾状山羊草细胞质在杂种小麦生产应用中可能有较大潜力．     

Preparation and properties of epichlorohydrin-cross-linked chitosan/hydroxyethyl cellulose based CuO nanocomposite films

This study introduces an effective route to fabricate chitosan (CS)-based film. The films were prepared through cross-linking reaction between CS and hydroxyethyl cellulose (HEC) using epichlorohydrin (ECH) as the cross-linker and simultaneously in-situ loading with CuO nanoparticles. FT-IR and loading efficiency results indicated the occurrence of inter- and intra-molecular cross-linking reaction between CS and HEC. XRD and EDS analyses showed that the CuO nanoparticles were evenly deposited onto CS film matrixes. SEM characterization showed that the films were of compact, dense and uniform cross morphologies, as well as obvious voids. The films also exhibited desired swelling ratio and water vapor permeability. The enhanced tensile strength was obtained with a maximum value of 77.02?±?3.26 MPa, while the stretch-ability slightly decreased. The thermal stability of the films decreased after cross-linking with HEC. The antibacterial ability of the films was generally improved with the increase of HEC and ECH contents.

Graphical abstract

Preparation and properties of epichlorohydrin-cross-linked chitosan/hydroxyethyl cellulose based CuO nanocomposite films