An approach to remove alpha amylase for proteomic analysis of low abundance biomarkers in human saliva

Proteomic characterization of human whole saliva for the identification of disease-specific biomarkers is guaranteed to be an easy-to-use and powerful diagnostic tool for defining the onset, progression and prognosis of human systemic diseases and, in particular, oral diseases. The high abundance of proteins, mainly alpha amylase, hampers the detection of low abundant proteins appearing in the disease state and therefore should be removed. In the present study a 2-DE was used to analyze human whole saliva following the removal of alpha amylase by affinity adsorption to potato starch. After alpha amylase removal whole saliva was analyzed by SDS-PAGE showing at least sixfold removal efficiency and by an alpha amylase activity assay showing 97% reduced activity. MS identification of the captured alpha amylase after elution demonstrated specific removal; 2-DE analysis showed the selective removal of alpha amylase and consequently increased gel resolution. MS identification of protein spots in the 60 kDa area revealed 15 proteins, which were masked before alpha amylase removal. In conclusion, treatment of human whole saliva with an alpha amylase removal device increases gel resolution and enables a higher protein sample for analysis.     

Electron-induced dissociation of glycosaminoglycan tetrasaccharides

Electron detachment dissociation (EDD) Fourier transform mass spectrometry has recently been shown to be a powerful tool for examining the structural features of sulfated glycosaminoglycans (GAGs). The characteristics of GAG fragmentation by EDD include abundant cross-ring fragmentation primarily on hexuronic acid residues, cleavage of all glycosidic bonds, and the formation of even- and odd-electron product ions. GAG dissociation by EDD has been proposed to occur through the formation of an excited species that can undergo direct decomposition or ejects an electron and then undergoes dissociation. In this work, we perform electron-induced dissociation (EID) on singly charged GAGs to identify products that form via direct decomposition by eliminating the pathway of electron detachment. EID of GAG tetrasaccharides produces cleavage of all glycosidic bonds and abundant cross-ring fragmentation primarily on hexuronic acid residues, producing fragmentation similar to EDD of the same molecules, but distinctly different from the products of infrared multiphoton dissociation or collisionally activated decomposition. These results suggest that observed abundant fragmentation of hexuronic acid residues occurs as a result of their increased lability when they undergo electronic excitation. EID fragmentation of GAG tetrasaccharides results in both even- and odd-electron products. EID of heparan sulfate tetrasaccharide epimers produces identical fragmentation, in contrast to EDD, in which the epimers can be distinguished by their fragment ions. These data suggest that for EDD, electron detachment plays a significant role in distinguishing glucuronic acid from iduronic acid.     

Miscellaneous PEDOT:PTS (polythiophenesulfonyl chloride) based conductive binder for silicon anodes in lithium ion batteries

Lithium ion batteries which are an energy storage system have increasing attention owing to suitability and advantages for many applications. Although it has ideal specifications, the capacity properties still have to be developed. In this study, the electrical conductivity of the anode was increased by using a conductive polymer binder and the active material content of the anode was also enhanced without adding carbon additives. Silicon based anodes were manufactured by using poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) and poly(3,4-ethylenedioxythiophene)/polythiophenesulfonyl chloride (PEDOT:PTS) conductive polymer binders. Si/PEDOT:PTS anode showed about 2000 mAh/g specific capacities after 60 cycles with decreasing impedance.     

Chemical Synthesis of Bioactive Proteins

Nature has developed a plethora of protein machinery to operate and maintain nearly every task of cellular life. These processes are tightly regulated via post-expression modifications—transformations that modulate intracellular protein synthesis, folding, and activation. Methods to prepare homogeneously and precisely modified proteins are essential to probe their function and design new bioactive modalities. Synthetic chemistry has contributed remarkably to protein science by allowing the preparation of novel biomacromolecules that are often challenging or impractical to prepare via common biological means. The ability to chemically build and precisely modify proteins has enabled the production of new molecules with novel physicochemical properties and programmed activity for biomedical research, diagnostic, and therapeutic applications. This minireview summarizes recent developments in chemical protein synthesis to produce bioactive proteins, with emphasis on novel analogs with promising in vitro and in vivo activity.     

Effect of sonication and freezing-thawing on the aggregate size and dynamic surface tension of aqueous DPPC dispersions

The effect of sonication and freezing-thawing on the aggregate size and dynamic surface tension of aqueous dipalmitoylphosphatidylcholine (DPPC) dispersions was studied by cryogenic-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), UV-vis spectroturbidimetry, and surface tensiometry. When 1000 ppm (0.1 wt%) DPPC dispersions were prepared with a certain protocol, including extensive sonication, they contained mostly frozen vesicles and were quite clear, transparent, and stable for at least 30 days. The average dispersed vesicles diameter was 80 nm in water and 90 nm in standard phosphate saline buffer. After a freeze-thaw cycle, this dispersion became turbid, and precipitates of coagulated vesicles were observed with large particles of average size of 1.5x10(3) nm. The vesicle coagulation is due to the local salt concentration increase during the freezing of water. This dispersion has much higher equilibrium and dynamic surface tension than those before freezing. When this freeze-thawed dispersion was subjected to a resonication at 55 degrees C, smaller vesicles with sizes of ca. 70 nm were produced, and a lower surface tension behavior was restored as before freezing. Similar behavior was observed at 30 ppm DPPC. These results indicate that the freeze-thaw cycle causes substantial aggregation and precipitation of the vesicles. These results have implications for designing efficient protocols of lipid dispersion preparation and lung surfactant replacement formulations in treating respiratory disease and for effective administration.     

菲啶和三苯基膦的Cu(Ⅰ)/Cu(Ⅱ)配合物的合成、表征和X射线晶体结构分析

以三苯基膦（PPh₃）为共配体,合成了2种新的铜（Ⅰ）和铜（Ⅱ）与菲啶（Phend）的配合物,其组成为[Cu（κ¹-Phend）₂Cl₂]（1）和[Cu₂（κ¹-Phend）₂（κ¹-PPh₃）₂（μ-Cl）₂]（2）。这些配合物的结构通过元素分析、摩尔电导率、FT-IR、UV-Vis和单晶X射线衍射进行了研究。典型配合物1的X射线衍射分析显示,Cu（Ⅱ）配位构型为扭曲的平面四方形,而双核配合物2的Cu（Ⅰ）中心为含μ-Cl^-离子的不规则四面体构型。FT-IR谱、元素分析以及UV-Vis谱证实了它们的成分、几何形状和配体相互作用。2种配合物的结构通过密度泛函理论（DFT）计算进行了优化,以解释电子光谱特性。     

Electromechanical characterization of biomimetic membranes using electrodeformation of vesicles

We describe a facile method to simultaneously measure the bending rigidity and capacitance of biomimetic lipid bilayers. Our approach utilizes the ellipsoidal deformation of quasi-spherical giant unilamellar vesicles induced by a uniform AC electric field. Vesicle shape depends on the electric field frequency and amplitude. Membrane bending rigidity can be obtained from the variation of the vesicle elongation on either field amplitude at fixed frequency or frequency at fixed field amplitude. Membrane capacitance is determined from the frequency at which the vesicle shape changes from prolate to oblate ellipsoid as the frequency is increased at a given field amplitude.     

Unitary periods,Hermitian forms and points on flag varieties

Let E be an imaginary quadratic extension of of class number one. We examine certain representation numbers associated to Hermitian forms over E , which involve counting integral points on flag varieties. G. Chinta is partially supported by the NSF and by a Humboldt Research Fellowship.     

Effect of chromatographic conditions on liquid chromatographic chiral separation of terbutaline and salbutamol on Chirobiotic V column

In this study, a method for enantioseparation of terbutaline and salbutamol was established using Chirobiotic V column as a stationary phase. Polar ionic mode applying mobile phase containing ammonium nitrate in 100% ethanol, pH 5.1 was found to give the best separation. The salt concentration in the mobile phase and pH value were found to be the most important chromatographic factors affecting separation. Separation of enantiomers of these two basic analytes was complete in less than 10 min without applying ammonium trifluoroacetate (ATFA) or triethylamine (TEA) salts.