CircFLNB在骨髓源性细胞中的表达鉴定及功能分析

目的:探讨环状RNA hsa_circ_0066336(circFLNB)在骨髓源性细胞中的表达,并分析其潜在功能.方法:选择骨髓源性细胞THP-1和Jurket作为模式细胞,通过设计背对背引物获得circRNA,分析circRNA在2种模式细胞中表达的差异.采用T-A克隆手段构建质粒,进行测序、比对.用Arrayst...     

Single-Mode Lasing in Polymer Circular Gratings

In recent years, conjugated polymers have become the materials of choice to fabricate optoelectronic devices, owing to their properties of high absorbance, high quantum efficiency, and wide luminescence tuning ranges. The efficient feedback mechanism in the concentric ring resonator and its circularly symmetric periodic geometry combined with the broadband photoluminescence spectrum of the conjugated polymer can generate a highly coherent output beam. Here, the detailed design of the ultralow-threshold single-mode circular distributed feedback polymer laser is presented with combined fabrication processes such as electron beam lithography and the spin-coating technique. We observe from the extinction spectra of the circular gratings that the transverse electric mode shows no change with the increase of incident beam angle. The strong enhancement of the conjugated polymer photoluminescence spectra with the circular periodic resonator can reduce the lasing threshold about 19 µJ/cm². A very thin polymer film of about 110 nm is achieved with the spin-coating technique. The thickness of the gain medium can support only the zero-order transverse electric lasing mode. We expect that such a low threshold lasing device can find application in optoelectronic devices.     

纳米二氧化硅暴露对金属硫蛋白和人血清白蛋白二级结构的影响

目的研究纳米二氧化硅(NPSiO₂)对金属硫蛋白(MT)和人血清白蛋白(HSA)二级结构的影响,为深入探讨NPSiO₂的生物安全性提供基础数据。方法将3个浓度0.05,0.5和5 g·L^-1和3种粒径20,60和100 nm的NPSiO₂(NPSiO₂-20 nm,NPSiO₂-60 nm和NPSiO₂-100 nm)分别与MT 0.2 g·L^-1和HSA 0.25 g·L^-1按体积比1∶1混合,于25℃反应30 min后,使用圆二色谱仪检测MT和HSA的圆二色光谱改变,用Spectra Manager Version2软件分析MT和HSA中4种二级结构(α-螺旋、β-折叠、β-转角和无规卷曲)含量的变化。结果 3种粒径的NPSiO₂均可使MT的β-折叠在4种二级结构中所占比例减少、β-转角所占比例增加,其中NPSiO₂-60 nm 0.05 g·...     

糖尿病分子生物学研究的新领域：微RNAs（miRNAs）与β细胞生物学、胰岛素抵抗、糖尿病及其并发症

微RNAs是由19-23个核苷酸组成的RNA分子。它们能够中止mRNAs的翻译或降解mRNA,从而成为蛋白质表达的调控者。微RNAs能有力推进细胞的分化和发育。这种调节的异常相关β细胞生物学、胰岛素抵抗和糖尿病及其并发症。微RNA-375直接参与胰岛素分泌的调控。本研究证明,微RNAS密切相关于疾病的表现。近年新鉴定出一大批与疾病致病有关的微RNAs。本文所提供31种微RNAs的应用,仅作为研究案例如糖尿病肾病发病的趣谈,旨在引起《中国糖尿病杂志》读者和作者研究微RNAs的浓厚兴趣。     

Stabilization of Lyophilized Porcine Pancreatic Elastase

Porcine pancreatic elastase, a well-characterized serine protease, has been used as a model to assess the effects of excessive humidity on solid-state stability of the lyophilized protein. Elastase lyophilized without excipients retained full activity immediately after freeze-drying but became denatured upon continued storage at 40°C, 75% relative humidity. The extent of inactivation could be monitored through assays of amidolytic activity, as well as through changes in the circular dichroism (CD) and fluorescence spectra. Differential scanning calorimetry (DSC) was employed as a means of screening potential stabilizing additives; based on the results, sucrose and dextran 40 were selected for further evaluation. Both additives were effective in preventing denaturation. Possible mechanisms for the denaturation and stabilization of elastase are discussed.     

Structure–activity relationship of neuropeptide γ derived from mammalian and fish

Abstract: This study of relationship between structure and biologic activity was performed using five neuropeptide γs [NPγ; mammalian‐NPγ (M‐NPγ), trout‐NPγ (T‐NPγ), goldfish‐NPγ (G‐NPγ), bowfin‐NPγ (B‐NPγ), and shark‐NPγ (S‐NPγ)]. Circular dichroism (CD) spectra showed that all peptides took random structure in buffer solution. In neutral and acidic liposomes, M‐NPγ, T‐NPγ, B‐NPγ, and S‐NPγ still adopted random structure, while G‐NPγ had an α‐helical structure. The biologic activity of NPγs has been estimated by their effects on the intestinal motility and arterial relaxation. The intestinal motility was investigated with rat duodenum (RD), carp intestine (CI), and guinea‐pig ileum (GPI). The arterial relaxing effect was tested with guinea‐pig aorta (GPA) and rat mesenteric artery (RMA). In RD, the order of potency compared with the EC₅₀ value was M‐NPγ > S‐NPγ > B‐NPγ > G‐NPγ > T‐NPγ. G‐NPγ was the most contractile agent in CI. S‐NPγ was the most contractile agent in GPI. Using an arterial relaxing test, the order of potency was G‐NPγ > T‐NPγ > B‐NPγ > S‐NPγ > M‐NPγ in GPA, and all NPγs remarkably reduced relaxing activity in RMA. Despite their structural similarities to NPγs, G‐NPγ has high affinity to tachykinin receptor‐binding sites in GPA and CI, indicating an α‐helical structure may have a critical role for receptor binding. However, an α‐helical structure does not play a critical role in recognizing receptor‐binding sites in RD and GPI.     

鹰嘴豆分离蛋白质的特性

研究了鹰嘴豆分离蛋白质质量、功能性质、物理化学性质及结构特征．氨基酸分析表明，鹰嘴豆蛋白含有所有必需氨基酸，与FAO／WHO模式相比，色氨酸是其第一限制性氨基酸，蛋白质的化学评分为71分．表面荧光探针ANS法测得的表面疏水性为94．3．DSC热分析显示该蛋白质含有两个热变性温度，分别为83．7℃和95．7℃．圆二色谱(CD)分析了鹰嘴豆分离蛋白的二级结构：α-螺旋36．2％，β-折叠28．4％，转角10．3％，无规卷曲25．2％．经凝胶过滤色谱Sephacryl S-200分离纯化得到7个不同相对分子质量蛋白质组分，其中两个主要组分的相对分子质量为170000及110000．     

A Meccano set approach of joining trpzip a water soluble β‐hairpin peptide with a didehydrophenylalanine containing hydrophobic helical peptide

Abstract: A 16 residues long, water soluble, monomeric β‐hairpin peptide ‘trpzip’ (Cochran et al. Proc. Natl. Acad. Sci. U.S.A., 98 (2001), 5578), stabilized by tryptophan zipper has been linked via a tetraglycyl linker to a hydrophobic didehydrophenylalnine (ΔF) containing helical octapeptide. Circular dichroism studies of this 28 residues long peptide, ‘trpzipalpha’ (Ac‐GEWTWDDATKTWTWTE‐GGGG‐ΔFALΔFALΔFA‐NH₂) in water have revealed the presence of both the β‐hairpin and the helical conformations. This is the first instance where a ΔF containing peptide has been found to display a helical fold in water. The fluorescence emission wavelengths of tryptophan in Ac‐G‐W‐G‐NH₂, trpzip and trpzipalpha were 341.5, 332.8 and 332.6 nm, respectively. The fluorescence quantum yield of trpzip was 2.6‐fold higher than trpzipalpha suggesting that proximal interactions between the β‐hairpin and the helix caused the quenching of tryptophan fluorescence in the former by the ΔFs in the latter. The molar ellipticity of the far UV couplet characteristic of trpzip was reduced in trpzipalpha and the CD based thermal melting temperatures at 228 nm were 62 °C (trpzip) and 57 °C (trpzipalpha). A concentration‐dependent variable temperature CD study in water showed that in trpzipalpha, increasing temperature is detrimental to the β‐hairpin, but it augments the helical motif, perhaps by intermolecular oligomerization. Our results show that in water, trpzipalpha exhibits long‐range interactions between two different secondary structures. In contrast to trpzip, trpzipalpha has shown a greater tendency to oligomerize in water.