PEG引发预防大豆种子吸胀冷害的研究

黑河3号大豆种子对低温吸胀非常敏感，PEG引发处理明显提高抗吸胀冷害能力。引发处理的效果与引发后种子含水量的提高有关。引发3天种子含水量达到34%左右。 引发处理过程中种子呼吸强度提高，呼吸商大于1。引发3天大豆种子胚根细胞ATP酶活性定位于质膜、细胞壁及细胞间隙。 引发种子和对照种子低温吸胀后，在常规增减条件下生理生化过程有显著的不同，这些差异与二者不同的种子活力水平有关。引发种子浸种过程中细胞物质损失少，膜选择性通透能力强。对照种子有大量物质外渗，特别是K+。引发种子常规培养条件下呼吸强度上升很快，RQ较低。对照种子呼吸强度很低。引发种子线粒体以L－Mal、α－Kg和Succ为底物时，具有较高的ADP／O和RC，并且氧化磷酸化活性出现早。对照种子线粒体氧化磷酸化功能不健全。引发种子胚根细胞ATP酶活性定位于质膜、核仁、胞间连丝及液泡膜。对照种子ATP酶活性在各亚细胞结构大为降低。 本文讨论了吸胀冷害的普遍性以及吸胀冷害对农业生产的影响，并推论低温吸胀主要导致敏感种子吸胀初期正在进行结构转化的膜系统不可逆损伤从而种子活力下降。PEG引发处理具有防止低温吸胀时膜系统伤损和修复种子成熟、加工、干燥贮藏阶段损伤的作用。PEG引发还预先活化了种子代谢系统。从而使种子萌发迅速、整齐，显著地提高敏感种子搞吸胀冷害能力，对于不存在吸胀冷害问题的种子，PEG引发也有提高种子活力的效果。

PEG诱导的柱胞鱼腥藻（Anabaenacylindrica）原生质球融合

以多盐复合液配制的ＰＥＧ溶液可诱导柱胞鱼腥藻原生质球融合，融合率约５％，融合时间６～４０ｍｉｎ，可发生两个或多个原生质球的融合，ＰＥＧ使用浓度１０％

Viscoelastic analysis of single-component and composite PEG and alginate hydrogels

Hydrogels, three-dimensional hydrophilic polymer networks, are appealing candidate materials for studying the cellular microenvironment as their substantial water content helps to better mimic soft tissue. However, hydrogels can lack mechanical stiffness, strength, and toughness. Composite hydrogel systems have been shown to improve upon mechanical properties compared to their singlecomponent counterparts. Poly (ethylene glycol) dimethacrylate (PEGDMA) and alginate are polymers that have been used to form hydrogels for biological applications. Singlecomponent and composite PEGDMA and alginate systems were fabricated with a range of total polymer concentrations. Bulk gels were mechanically characterized using spherical indentation testing and a viscoelastic analysis framework. An increase in shear modulus with increasing polymer concentration was demonstrated for all systems. Alginate hydrogels were shown to have a smaller viscoelastic ratio than the PEGDMA gels, indicating more extensive relaxation over time. Composite alginate and PEGDMA hydrogels exhibited a combination of the mechanical properties of the constituents, as well as a qualitative increase in toughness. Additionally, multiple hydrogel systems were produced that had similar shear moduli, but different viscoelastic behaviors. Accurate measurement of the mechanical properties of hydrogels is necessary in order to determine what parameters are key in modeling the cellular microenvironment. © 2014 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

双结晶性PEG-PCL两嵌段共聚物的合成，结晶行为和形态

聚乙二醇－聚ε-己内酯两嵌段共聚物（PEG-PCL）由于其在生物医用材料中的潜在应用而受到广泛的关注。然而，研究表明这类嵌段共聚物的许多性质，如药物渗透性，降解性能和机械性质等，都要受到它们的结晶行为与聚集态结构的显著影响。而在本课题开始之前，还没有关于PEG-PCL的结晶行为与形态的系统研究报道。因此，本文希望通过对PEG-PCL两嵌段共聚物结晶行为与形态的研究，能为这类生物降解高分子材料的工业应用提供一定的科学依据。本文使用辛酸亚锡为催化剂，甲氧基聚乙二醇（mPEG）为大分子引发剂，合成了一系列分子量分布比较窄，PCL质量百分含量为0.16-0.93的PEG-PCL两嵌段共聚物。两嵌段共聚物中的PEG段分子量固定为5000，共聚物的组成通过改变PCL链段的长度来调节。本文使用DSC，WAXD，常温或变温FTIR详细研究了PEG-PCL的结晶和熔融行为，使用偏光显微镜（POM）观察了PEG-PCL的结晶形态及结晶生长行为，利用SAXS研究了PEG-PCL的微观形态，得出了如下结果：（1）WAXD与FTIR的结果表明，两嵌段共聚物中的PEG与PCL形成微相分离的结晶微区，不存在两者的共晶或混晶。PCL含量为0.23-0.87的两嵌段共聚物中都能观察到的PEG与PCL的结晶。变温FTIR结果显示，当PCL含量低于或等于0.36，两嵌段共聚物中的PEG先从熔体中结晶；反之，当PCL含量等于或大于0.43，则熔体中PCL结晶先出现。（2）DSC结果表明，随着PEG-PCL中PCL段长度的增加，PCL段的结晶和熔融温度显著增加；相反，PEG段的结晶和熔融温度则显著降低。当PCL的质量分数由0增加至0.93，PEG的结晶度从79%降低至0，然而PCL的结晶度却不是单调变化，而是出现一个最大值。（3）在POM下观察PEG-PCL的36 oC等温熔体结晶过程，当PCL质量分数不超过0.36时，在偏光显微镜下只能观察到PEG球晶；而当PCL质量分数大于或等于0.56时，只能观察到PCL球晶；PCL含量为0.43和0.50的两种两嵌段共聚物中观察到了一种独特的同心球晶，同心球晶的中心部分形态类似于PCL球晶，而外部则类似于PEG球晶。PEG球晶与PCL球晶生长速率受PCL含量的影响显著：当PCL质量分数从0增加至0.50，PEG球晶的生长速率大大降低；然而，PCL球晶的生长速率却不是单调变化，而是在PCL质量分数为0.62时达到最大值。（4）SAXS结果表明，结晶后的PEG-PCL的微区结构是由交替的PEG与PCL的层状微区组成。共聚物的长周期在PCL质量分数为0.50时达到最大值。当PCL质量分数由0增加至0.50时，由于PCL层厚度的显著增加，共聚物的长周期显著增加；而当PCL含量由0.50继续增加至0.87，由于PEG层厚度的急剧降低，又使得共聚物的长周期迅速降低。（5）首次利用POM和微区红外光谱详细研究了PEG-PCL50/50(w/w)同心球晶的形成过程，发现同心球晶的形成是由于一种独特的结晶动力学造成的。另外，即使同心球晶的中心和外部的形态差别巨大，但是红外显微镜结果显示，两部分的组成却是相同的。

聚乙二醇模拟干旱对甜高粱幼苗丙二醛、脯氨酸含量的影响；Effects of Drought Stress Simulated by PEG on Malonaldehyde and Proline Contents of Sweet Sorghum Seedlings

以甜高粱品种KFJT-CK及经过碳离子辐照选育出的早熟突变株KFJT-1为材料,用浓度分别为5%,10%和15%的聚乙二醇(PEG)6000模拟干旱对其进行胁迫处理,测定丙二醛(MDA)及脯氨酸(Pro)的含量。随着胁迫时间的延长和胁迫程度的增加,MDA含量持续升高;Pro含量在5%和10%PEG胁迫下持续升高,在15%PEG胁迫下先升高后降低。表明碳离子辐照可能使甜高粱膜脂过氧化特性发生改变,影响Pro的表达。为进一步研究碳离子束辐照对甜高粱的耐旱生理提供一定的基础,并为下一步的育种工作提供有用的参考。

Self-Assembly of Hyperbranched Multiarmed PEG-PEI-PLys(Z) Copolymer into Micelles, Rings, and Vesicles

Self-assembling of synthesized novel biodegradable hyperbranched amphiphilic poly(ethylene glycol)-polyethylenimine-poly(epsilon-benzyloxycarbonyl-L-lysine) (PEG-PEI-PLys(Z)) in aqueous media is studied. In aqueous media. PLys(Z) is the hydrophobic segment, with PEG and PEI as the hydrophilic segments. It will self-assemble into spherical shape when the selected solvent water is dropped into the common solvent tetrahydrofuran (THF). And when PEG-PEI-PLYS in common solvent is dropped into mixed solvent water and THF, rings will come into King. The spherical and rings are observed by environmental scanning electron microscopy (ESEM) and transmission electron microscopy ITEM). It shows that the size of the sphere is about 100 nm, and the diameter of ring distributes from 400 nm to 10 mu m and bigger with the time roll around.

Ultrafine PEG-PLA fibers loaded with both paclitaxel and doxorubicin hydrochloride and their in vitro cytotoxicity

By means of "emulsion-electrospinning", both hydrophobic and hydrophilic drugs, paclitaxel (PTX) and doxorubicin hydrochloride (DOX), were successfully loaded into PEG-PLA nanofiber mats to realize multi-drug delivery. The release behaviors of both the drugs from the same fiber mats were ascribed to their solubility properties and distribution status in the fibers. Due to its high hydrophilicity, DOX was easy to diffuse out from the fibers, and its release rate was always faster than that of hydrophobic PTX. Moreover, the release rate of PTX was accelerated by DOX's release from the same drug-loaded fibers. In vitro cytotoxicity against rat Glioma C6 cells indicated that the dual drug combination showed a higher inhibition and apoptosis against C6 cells than a single drug-loaded system, which suggests the promise for multi-drug delivery on combination therapy.

交联型聚乙烯亚胺智能基因载体的制备及PEG化影响

使用胱胺双丙烯酰胺(CBA)对低分子量聚乙烯亚胺(PEI)进行交联反应制备智能降解型聚阳离子基因载体.通过与聚乙二醇(PEG)反应得到不同程度PEG化的聚阳离子载体.利用核磁、黏度测试、粒度仪、zeta电位仪和凝胶电泳对聚阳离子载体及其与DNA的复合物进行了表征.研究表明随着PEG含量的增加,聚阳离子载体/DNA复合物颗粒粒径变小、表面正电荷降低,PEG具有明显的屏蔽作用,但过多的PEG也使载体与DNA复合能力下降.通过MTT细胞毒性测试和荧光素酶质粒转染实验得出,含二硫键的交联型阳离子聚合物在测试范围内显示了非常低的细胞毒性,最佳转染效率是PEI25k的4倍,PEG化后其细胞毒性得到进一步改善,转染效率却明显降低.