Advancements in the Development of non-BET Bromodomain Chemical Probes

The bromodomain and extra terminal (BET) family of bromodomain-containing proteins (BCPs) have been the subject of extensive research over the past decade, resulting in a plethora of high-quality chemical probes for their tandem bromodomains. In turn, these chemical probes have helped reveal the profound biological role of the BET bromodomains and their role in disease, ultimately leading to a number of molecules in active clinical development. However, the BET subfamily represents just 8/61 of the known human bromodomains, and attention has now expanded to the biological role of the remaining 53 non-BET bromodomains. Rapid growth of this research area has been accompanied by a greater understanding of the requirements for an effective bromodomain chemical probe and has led to a number of new non-BET bromodomain chemical probes being developed. Advances since December 2015 are discussed, highlighting the strengths/caveats of each molecule, and the value they add toward validating the non-BET bromodomains as tractable therapeutic targets.     

Increased Histone Acetylation and Decreased Expression of Specific Histone Deacetylases in Ultraviolet-Irradiated and Intrinsically Aged Human Skin In Vivo

Histone deacetylases (HDACs) are conserved enzymes that remove acetyl groups from lysine side chains in histones and other proteins and play a crucial role in epigenetic regulation. Previously, we showed that histone acetylation is implicated in ultraviolet (UV)-induced inflammation and matrix impairment. To elucidate the histone acetylation status and specific HDACs involved in skin aging, we examined the changes in histone acetylation, global HDAC activity, and the expression of HDACs and sirtuins (SIRTs) in intrinsically aged and photoaged human skin as well as in UV-irradiated human skin in vivo. Following acute UV irradiation, the acetylated histone H3 (AcH3) level was increased, but HDAC activity and the expression levels of HDAC4, HDAC11, and SIRT4 were significantly decreased. In intrinsically aged skin, AcH3 levels were increased, but HDAC activity and the expression levels of HDAC4, HDAC5, HDAC10, HDAC11, SIRT6, and SIRT7 were significantly decreased. However, histone acetylation and HDAC expression in photoaged skin were not significantly different from those in intrinsically aged skin. Collectively, HDAC4 and HDAC11 were decreased in both UV-irradiated and intrinsically aged skin, suggesting that they may play a universal role in increased histone acetylation associated with skin aging.     

高取代度玉米淀粉醋酸酯的合成与表征

以玉米淀粉为原料,醋酸酐为酯化剂,甲烷磺酸为催化剂,制备高取代度淀粉醋酸酯。研究了反应条件对产品取代度和结构的影响。结果表明:在n(淀粉葡萄糖基)∶n(醋酸酐)=1∶5.18,甲烷磺酸0.003 5 mol,反应温度75℃的条件下反应3 h,合成了取代度2.83的淀粉醋酸酯。用FTIR和1HNMR方法研究了淀粉醋酸酯的化学结构。FTIR分析表明,随着取代度的增加淀粉醋酸酯的特征峰逐渐增强;根据1HNMR谱峰的变化计算了淀粉醋酸酯的取代度,与化学滴定法测定的取代度一致;通过X射线衍射、偏光显微镜分析表明,酯化反应过程中破坏了原淀粉的结晶结构,生成了具有非晶态结构的淀粉醋酸酯。该淀粉酯已经过扩大生产,性能良好。     

乙酰化淀粉/PBS制备生物降解塑料的研究

以玉米淀粉为原料,以醋酸酐为乙酰化试剂,氢氧化钠为催化剂,利用微波辐射技术制得乙酰化淀粉。用制备的乙酰化淀粉与聚丁二酸丁二醇酯(PBS)共混,制备了可生物降解热塑性淀粉塑料。研究了共混物制备的最佳工艺条件及其力学性能、生物降解性能及吸水性能,并对产物进行了红外光谱结构分析和表面电镜扫描分析。     

乙酰化壳聚糖微球作为潜在动脉栓塞剂的研究

利用优化后的乳化交联法制备的壳聚糖微球(CMs)及其乙酰化微球(ACMs)表面光滑、球形完整、粒径均匀。微球溶胀率试验、体外降解试验和细胞毒性试验显示,ACMs多种特性较CM更优。采用ACMs对兔耳栓塞15d后,栓塞部位小动脉萎缩消失,周围组织坏死,部分发生脱落,与坏死组织交界的边缘表皮萎缩增厚。结果表明,ACMs可以作为潜在的动脉栓塞剂。     

变性淀粉在面包制品中的应用研究进展

在面包生产中，变性淀粉得到了越来越多的关注。不同种类的化学改性淀粉在面团和面包的质地和质量上起着不同的作用，适量的变性淀粉有利于提高面包制品的品质和质量。文章对不同类型的变性淀粉在面包上的应用进行了综述。     

Acetylated and native corn starch blend films produced by blown extrusion

Thermoplastic starch (TPS) materials were developed from mixtures of native and acetylated corn starches with glycerol. To optimize the formulations an experimental design for multicomponent mixtures was used and the assayed formulations were determined by statistical software. Blends and pellets humidity content increased with glycerol concentration. Starch destructuration during the extrusion process was studied by thermal analysis. Films presented homogenous structure, rough surfaces and certain stickiness. They presented different properties, related mainly to the differential characteristics of native and acetylated starches and to hydrophilic character of glycerol. Their mechanical behavior indicated that they are a good option as a food packaging materials since TPS films resulted enough resistant to protect the product and flexible to resist moderate deformations. Besides, the use of acetylated starch in the formulations enhanced film resistance and reduced their WVP, despite of its low modification degree. The storage of the films under controlled conditions increased their stiffness, while their flexibility and WVP were reduced. Plasticizer migration towards the matrix surface was observed in stored films. Films resulted stable till a_w = 0.7 and due to their selective gaseous permeability they are useful to package products susceptible to oxidation or to control vegetable respiration and senescence.     

ZIF-67原位负载纳米纤维素基锂离子电池隔膜的制备及性能研究

本研究以纳米纤维素（CNF）为原料,经乙酰化、原位负载ZIF-67和浸渍电解液制备出一种新型ZIF-67@乙酰化纳米纤维素（ZIF-67@ACNF）锂离子电池隔膜,系统探讨了ZIF-67的粒径对隔膜结构及性能的影响。结果表明,当ZIF-67的粒径从0.46 μm（ZIF-67₄@ACNF隔膜）减小至0.25 μm（ZIF-67₈@ACNF隔膜）时,隔膜的孔隙率从74.2%减小至52.1%,离子电导率从0.75 mS/cm下降至0.22 mS/cm,界面电阻从112.5 Ω增加至1 115.7 Ω,锂离子迁移数从0.41减小至0.31,电化学稳定窗口从5.1 V减小至4.5 V。采用ZIF-67₄@ACNF隔膜组装电池,在室温、0.5 C的条件下进行电池充/放电测试,初始容量达到159.6 mAh/g,循环200圈后容量保持率达到90%。     

Log‐normal distribution for a description of the molecular weight distribution of N‐acetylated chitosans depolymerized with hydrolytic enzyme

N‐acetylated chitosans (NACs) with different degrees of N‐acetylation (DAs) were enzymatically depolymerized at pH 5.1 and 40 °C, and the molecular weight distributions (MWDs) of the depolymerized NACs were then measured by size exclusion chromatography and were fitted by the log‐normal distribution function with two distribution parameters, β and M₀. We discuss also the time‐evolution of the distribution parameters derived from the experimentally obtained MWD as well as the effects of experimental conditions, such as DA and initial NAC concentration (S₀), on the distribution parameters. Copyright © 2003 Society of Chemical Industry     

气相色谱法分析工业甘油——乙酰衍生物法

油脂水解法生产的甘油样品用乙酸酐进行乙酰化处理,采用21m×0.25mmOV 225弹性石英毛细管色谱柱氢焰离子化检测器进行气相色谱分析。GC/MS定性鉴定,以苯甲酸甲酯为内标的内标定量法。回收率可达98%,变异系数为0.6%,结果准确、可靠,具有一定的理论和实践参考价值。