含二硫键的蛋白质/多肽的MALDI-TOF MS源内裂解研究

应用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)法研究含二硫键的人胰岛素与甘精胰岛素酶解液的源内裂解(ISD)。比较了不同基质种类及不同结晶状态对含二硫键的人胰岛素与甘精胰岛素酶解液的源内裂解的影响。结果表明,含二硫键的蛋白质的ISD发生受激光点照射位置的影响,在不同基质与结晶形态的条件下,含二硫键的蛋白质的ISD碎片信息不同。通过分析比较,含二硫键的蛋白质的ISD较容易控制,并且其基质的种类及结晶状态作用很关键。需要获得大量碎片时,使激光照射在样品和阿魏酸(FA)基质形成的大结晶处;不希望出现碎片时,可使用2,4,6-三羟基苯乙酮(THAP)为基质,或使激光照射在样品和其他基质形成的细小均匀结晶处。     

MALDI-TOF MS与16SrDNA方法对肠杆菌科微生物鉴定比较分析

为了研究基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)法鉴定肠杆菌科微生物及其对微生物系统分类学相关分析的准确性,采用MALDI-TOF MS对金桔表面分离的10种肠杆菌科微生物进行蛋白质图谱收集,通过比对图谱特征峰实现微生物的鉴定与系统进化学分析;同时对10种微生物进行16SrDNA提取与测序,得到分子生物化学水平鉴定,并采用邻近连接法对16SrDNA序列做系统进化树分析。结果表明:MALDI-TOF MS与16SrDNA测序对10种肠杆菌科微生物鉴定结果中,克雷伯菌属2株菌鉴定种级有偏差,其他8种一致;MALDI-TOF MS与16SrDNA测得的数据都可计算微生物相关性,从而得到微生物系统发育树,两株系统发育树中同属级微生物归类的亲缘位置与方向一致,但不同属肠杆菌科微生物的亲缘距离与位置差异较大。MALDI-TOF MS法鉴定农产品表面微生物具有快速、准确的特点,但准确建立系统发育相关性还需要扩大数据库和优化算法。     

柠檬酸杆菌属基质辅助激光解析电离飞行时间质谱图谱库的扩展及效果评价

目的 扩展基质辅助激光解析电离飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)中柠檬酸杆菌属数据库.方法 采用PCR方法扩增并测序管家基因leuS进行系统发育分析鉴定菌种;采...     

Influence of side chains on electrochromic properties of green donor–acceptor–donor polymers

Three solution processable cathodically coloring green electrochromic polymers, based on 2,3-diphenyl-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine, have been synthesized by oxidative FeCl₃ polymerization. The polymers were designed with solubilizing alkyl and oligoethylene oxide side chains to achieve solubility and processability. All three polymers have a small electrochemical bandgap (1.8–1.9 eV) and low oxidation potentials. Spectroelectrochemical studies of polymer films on ITO reveal that the alkyl side chains in head-to-head position on the polymer backbone promote a defined high-energy absorption peak and suppress tailing of charge-carrier absorption into the visible region. Kinetic studies, based on transmission measurements applying a square-wave potential between reduced and oxidized states, show that the polymer with exclusively oligoethylene oxide side chains (P3) had the fastest response times, monitored at the low-energy absorption maxima. The best performing polymer (P1) showed a good optical contrast in the visible region with a ΔT of 26% at 700 nm. An initial test of the electrochemical stability showed that the oligoethylene oxide containing polymers had superior stability over 500 full switches.     

Microwave-assisted polymer synthesis (MAPS) as a tool in biomaterials science: How new and how powerful

Lack of reproducibility, difficult and expensive scale-up and standarization of synthetic processes are the main hurdles towards the industrial production of raw synthetic and semi-synthetic polymers for (bio)pharmaceutical applications. Time- and energy-consuming synthetic pathways that usually involve the use of volatile, flammable or toxic organic solvents are apparently cost-viable and environment-friendly for the synthesis at a laboratory scale. However, they are often not viable in industrial settings especially due to the impact they have on the product cost and the deleterious effect on the environment. This has presented hurdles to the incorporation of many new biomaterials displaying novel structural features into clinics. Nevertheless, owing to unique advantages such as shorter reaction times, higher yields, limited generation of by-products and relatively easy scale-up without detrimental effects, microwave-assisted organic synthesis has become an appealing synthetic tool. Regardless of these features, the use of microwave radiation in biomaterials science has been comparatively scarce. A growing interest in the basic aspects of the synthesis of either ceramic and polymeric biomaterials has been apparent during the last decade. This article reviews the most recent and prominent applications of MW as a versatile tool to synthesize and process organic and inorganic polymeric biomaterials, and discusses the unmet goals and the perspectives for a technology that probably has the potential to make biomaterials more accessible pharmaceutical excipients and the products that involve them more affordable to patients.     

Characterization of two maritime pine tannins as wood adhesives

Maritime pine tannins from the two suppliers BIOLANDES and DRT were used in combination with paraformaldehyde (5%), hexamine (6%) and glyoxal (9%) as hardener in the preparation of adhesives for wood-based panels. Both tannins showed similar structures according to the matrix-assisted laser desorption/ionization-time of flight analysis. A high reactivity has been checked by gel time measurements and the viscosity increase. Already the BIOLANDES and the DRT tannin alone registered an internal bond (IB) of 0.4?MPa without any hardener. The BIOLANDES tannin with paraformaldehyde could fulfil the European standard EN 312. In general, DRT tannin obtained the best mechanical results. However, the pH and the moisture content play a fundamental role for the final IB. Thus, DRT tannin with glyoxal as hardener at high pH and moisture content gave an IB of 0.51?MPa. The mechanical resistance differences between BIOLANDES and DRT tannin were confirmed by the ¹³C NMR spectra. DRT tannin presents a lower polymerization de than BIOLANDES, and more reactive sites are available.     

The Beauty and Complexity of the Mixed-Ligand Pd(II)-containing Monomers,Oligomers and Polymers Built upon Diphosphines and 1,8-Diisocyano-<Emphasis Type="Italic">p</Emphasis>-menthane

The starting materials Pd(diphos)Cl₂ where diphos = bis(diphenylphosphino)ethane (dppe), bis(diphenylphosphino)propane (dppp), bis(diphenylphosphino)butane (dppb), and Pd₂(diphos′)₂Cl₄ where diphos′ = bis(diphenylphosphino)pentane (dpppen) and bis(diphenylphosphino)hexane (dpph) were reacted with the bridging ligand 1,8-diisocyano-p-menthane (dmb) to form species of the type {Pd₂(diphos)₂(dmb) ₂ ⁴⁺ } _n and {Pd(diphos′)₂(dmb) ₂ ⁴⁺ } _n . Except for Pd₂(dppe)₂(dmb) ₂ ⁴⁺ , which was characterized by X-ray crystallography, the identity of the other weakly soluble dmb-containing materials were exhaustively characterized in solution and in the solid state by ³¹P NMR (Magic Angle Spinning), chemical analyses, MALDI-TOF, DSC, TGA, IR and T ₁/NOE (³¹P NMR spin-lattice relaxation time and nuclear overhauser enhancement constant measurements). Model compounds such as Pd(diphos)(CN-tBu) ₂ ²⁺ (diphos = dppe, dppp, dppb) and Pd₂(diphos′)₂(CN-tBu) ₄ ⁴⁺ (diphos′ = dpppen, dpph; as BF ₄ ⁻ or PF ₆ ⁻ salts), were prepared and also characterized by X-ray crystallography. Evidence for mono- (model complexes only of the type dppe, dppp, and dppb) and dinuclear complexes, as well as oligomers and polymers, are obtained for most cases, as well as the presence of monomer–oligomer (or polymer) equilibrium. During the course of this study, the complexes [Pd(dppp)(CN-tBu)₂](TCNQ)(Cl), [Pd₂(dpppen)₂(CN-tBu)₂(Cl)₂](PF₆)₂, and [Pd₂(dpppen)₂(CN-tBu)₂(CN)₂](TCNQ)₂ (TCNQ⁻ = tetraquinodimethane anion) were isolated and characterized by X-ray crystallography.This paper is dedicated to Professor Richard J. Puddephatt.     

Optimization and Evaluation of Magnetic Bead Separation Combined with Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectroscopy (MALDI-TOF MS) for Proteins Profiling of Peritoneal Dialysis Effluent

Peritoneal dialysis effluent (PDE) potentially carries an archive of peptides relevant to pathological processes in abdominal and surrounding tissues. Magnetic beads and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is one such approach that offers a unique tool for profiling of peptides, but this approach has not been used in the PDE analysis. In this study, we developed a strategy for screening PDE proteins <15 kDa and applied this technique to identify potential biomarkers for peritonitis. We examined four kinds of magnetic beads, including a carbon series (C3, C8), weak cation exchange (WCX) and immobilized metal-affinity chromatography (IMAC-Cu) beads. Samples processed with IMAC-Cu magnetic beads consistently showed more MS signals across all beads within the measured mass range. Moreover, there was no difference in the number and morphology of MS signals between concentrated and unconcentrated samples. The PDE peptidome pattern, based on a panel of 15 peaks, accurately recognized peritonitis PD patients from peritonitis-free patients with sensitivity of 90.5% and specificity of 94.7% respectively. Therefore, IMAC-Cu magnetic beads and unconcentrated samples can be used as a fast and cost-effective approach for sample preparation prior to more in-depth discovery of predictive biomarkers of disease in patients on dialysis.