Investigation of the interaction between HIV-1 DNA and cyclic peptides by electrospray ionization mass spectrometry

The interaction between HIV-I DNA and five cyclic peptides (CPI-CP5) was investigated using electrospray ionization mass spectrometry (ESI-MS). It revealed that CPI [c(Ala-Tyr-Leu-Ala-Gly)] and CP4 [c(Pro-D-Tyr-Leu-D-Ala-Gly)] have the higher binding affinity with the duplex DNA among the five cyclic peptides.     

Autocrine‐Based Selection of Drugs That Target Ion Channels from Combinatorial Venom Peptide Libraries

Animal venoms represent a rich source of pharmacologically active peptides that interact with ion channels. However, a challenge to discovering drugs remains because of the slow pace at which venom peptides are discovered and refined. An efficient autocrine‐based high‐throughput selection system was developed to discover and refine venom peptides that target ion channels. The utility of this system was demonstrated by the discovery of novel Kv1.3 channel blockers from a natural venom peptide library that was formatted for autocrine‐based selection. We also engineered a Kv1.3 blocker peptide (ShK) derived from sea anemone to generate a subtype‐selective Kv1.3 blocker with a long half‐life in vivo.     

水热法合成MOS2层状材料及其结构表征

以硫脲为还原剂和硫源,利用水热法在160～220℃下反应,合成了具有很好晶相的MoS2．采用XRD,XPS和TEM对其进行了结构表征,比较了反应温度对于成晶的影响,并且讨论了反应机理．研究表明,用此种方法合成MoS2较以往的水热合成所用时间短,温度低,获得的晶相好,同时还有效地避免了使用吡啶等有机溶剂所带来的污染,为合成其他过渡金属硫化物提供了新途径．     

Fe(phen)32+‐Modified Zeolite Particles and Their Energetic Studies

Chemically modified zeolite Y (NaY) particles and their resulting modified electrodes were prepared with acridinium (AcH+), iron(II) and 1,10‐phenanthroline (phen) for energetic studies. According to diffuse reflectance absorption spectroscopy and cyclic voltammetry, AcH⁺ and Fe(phen)₃²⁺ were successfully entrapped in the zeolite particles. Transient emission spectra measurements showed that the life time of AcH+* in the zeolite particles (to 35 ns; λ_ex 365 nm; λ_em 500 nm) was greatly reduced upon incorporating Fe(phen)₃²⁺ and Fe²⁺. The fast de cay of AcH+*(NaY) suggested that a reductive quench was likely to take place in the zeolite particle. Probably due to a size‐exclusion effect, the bulky electron donor, N, N‐diethyl‐2‐methyl‐1,4‐phenylenediamine (DEPD), revealed a difficulty in reaching the photosensitizer, AcH⁺, in side the zeolite particle. As a consequence, the in significant photocurrent for the oxidation of DEPD was from the NaY|AcH⁺ electrode. However, if Fe²⁺ and Fe(phen)₃²⁺ were incorporated, the photocurrent would become more significant. Closer examinations, in addition, showed that the photooxidaton of DEPD occurred more rapidly on the NaY|AcH⁺|Fe(phen)₃²⁺ electrode, compared to the NaY|AcH⁺|Fe²⁺ electrode. This difference apparently results from a greater gap in energetics between DEPD and Fe(phen)₃³⁺_(NaY) than that between DEPD and Fe³⁺_(NaY). Due to this effect, a greater amount of indophenol blue, derived from the coupling reaction of the oxidized DEPD with 1‐naphthol, was formed and de posited on the NaY|AcH⁺|Fe(phen)₃²⁺modified electrode. Thanks to this photo‐induced charge‐transfer reaction, the NaY|AcH⁺|Fe(phen)₃²⁺ particle showed an application potential in image recording.     

A novel way towards CdS sensitized TiO_2 nanoparticles

<正>Polymethyl methacrylate cadmium was grafted on TiO_2 surface via the surface initiated atomic transfer radical polymerization of methyl methacrylate cadmium from a surface tether initiator.The coordinated cadmium as the source precursor reacts with H_2S generates CdS nanoscrystal on TiO_2 surface.The grain size of CdS is about 5 nm and stabilized by tether polymer chains.The light absorption of CdS/TiO_2 is expanded to visible light region.     

Ultra-sensitive trace analysis of cyanide water pollutant in a PDMS microfluidic channel using surface-enhanced Raman spectroscopy

Rapid and highly sensitive trace analysis of cyanide water pollutant in an alligator teeth-shaped PDMS microfluidic channel was investigated using surface-enhanced Raman spectroscopy. Compared with previously reported analytical methods, the detection sensitivity was enhanced by several orders of magnitude.     

Selecting Agonists from Single Cells Infected with Combinatorial Antibody Libraries

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Discriminant analysis of prion sequences for prediction of susceptibility

Prion diseases, including ovine scrapie, bovine spongiform encephalopathy (BSE), human kuru and Creutzfeldt–Jakob disease (CJD), originate from a conformational change of the normal cellular prion protein (PrP^C) into abnormal protease-resistant prion protein (PrP^Sc). There is concern regarding these prion diseases because of the possibility of their zoonotic infections across species. Mutations and polymorphisms of prion sequences may influence prion-disease susceptibility through the modified expression and conformation of proteins. Rapid determination of susceptibility based on prion-sequence polymorphism information without complex structural and molecular biological analyses may be possible. Information regarding the effects of mutations and polymorphisms on prion-disease susceptibility was collected based on previous studies to classify the susceptibilities of sequences, whereas the BLOSUM62 scoring matrix and the position-specific scoring matrix were utilised to determine the distance of target sequences. The k-nearest neighbour analysis was validated with cross-validation methods. The results indicated that the number of polymorphisms did not influence prion-disease susceptibility, and three and four k-objects showed the best accuracy in identifying the susceptible group. Although sequences with negative polymorphisms showed relatively high accuracy for determination, polymorphisms may still not be an appropriate factor for estimating variation in susceptibility. Discriminant analysis of prion sequences with scoring matrices was attempted as a possible means of determining susceptibility to prion diseases. Further research is required to improve the utility of this method.     

Biosynthesis of Glucosyl Glycerol,a Compatible Solute,Using Intermolecular Transglycosylation Activity of Amylosucrase from Methylobacillus flagellatus KT

A putative α-amylase gene (accession number, CP000284) of Methylobacillus flagellatus KT ATCC51484 was cloned in Escherichia coli, and its gene product was expressed and characterized. The purified recombinant enzyme (MFAS) displayed a typical amylosucrase (ASase) activity by the demonstration of multiple activities of hydrolysis, isomerization, and polymerization although it was designated as an α-amylase. The optimal reaction temperature and pH for the sucrose hydrolysis activity of MFAS were determined to be 45 °C and pH 8.5, respectively. MFAS has relatively high thermostable characteristics compared with other ASases, as demonstrated by a half-life of 19.3 min at 50 °C. MFAS also showed polymerization activity using sucrose as a sole substrate. Glycerol was transglycosylated by the intermolecular transglycosylation activity of MFAS. Two major products were observed by thin-layer chromatography and isolated by paper chromatography and recycling HPLC. Using ¹H and ¹³C NMR, their chemical structures were determined to be (2S)-1-O-α-d-glucosyl-glycerol or (2R)-1-O-α-d-glucosyl-glycerol and 2-O-α-d-glucosyl-glycerol, in which a glucose molecule is linked to glycerol via an α-glycosidic linkage.     

Qualitative and quantitative identification of copper oxides

The quality, thickness, and chemistry of oxides on metal surfaces play a vital role in a variety of applications. Some of these include adhesion of elastomers to metal surfaces, solar cell efficiency, sealing of electronic packaging, reduction of friction during wet drawing, and degree of biocompatibility of biomaterials. However, contradictory results and misidentification of oxide layers on metallic surfaces have caused ambiguity in interpretation of results leading to incorrect use in industrial application. This study will focus on the effect of experimental parameters such as electrolyte composition and concentration, current density, coating, time constant, surface roughness, and concentration of depolarizer on cathodic reduction of oxides on metallic wires to yield precise measurement and correct identification of oxide layers. Copyright © 2008 John Wiley & Sons, Ltd.