Exploiting bias in a non-immune human antibody library to predict antigenicity

Non-immune human antibody fragment libraries have generated antigen-binding proteins useful as prospective research, imaging, diagnostic and therapeutic agents. However, because the generation of such libraries relies on cloning antibody sequences from the circulating immune repertoire rather than truly na?ve, germline sequences, their composition may reflect the deletion of autoreactive sequences, making them less suited for isolating binding clones to human antigens, but perhaps useful in applications where an in vitro handle on representative circulating antibody diversity is desired. Here we demonstrate that a large non-immune human scFv library is relatively depleted of sequences capable of recognizing human antigens as compared with orthologs antigens. Additionally, because this non-na?ve, non-immune library may capture a representative section of antibody diversity, we explore its possible utility in conducting early pre-screens to predict the antigenicity of prospective therapeutics and find a correlation between the clinical immunogenicity of a small panel of protein therapeutics with their propensity for interacting with the library.     

Geometric invariant core for the V(L) and V(H) domains of immunoglobulin molecules

A new algorithmic method for identifying a geometric invariant of proteinstructures, termed geometrical core, is developed. The method used thematrix of C(alpha)-C(alpha) distances and does not require the usualsuperposition of structures. The result of applying the algorithm to 53immunoglobulin structures led to the identification of two geometrical coresets of C(alpha) atoms positions for the V(L) and V(H) domains. Based onthese geometric invariants a preferred coordinate system for theimmunoglobulin family is constructed which serves as a basis for structuralprediction. The X-ray atom coordinates for all available immunoglobulinstructures are transformed to the preferred coordinate system. An affinesymmetry between the V(L) and V(H) domains is defined and computed for eachof the 53 immunoglobulin structures.     

Investigation on V(IV)/V(V) species in a vanadium redox flow battery

Stokes radii of V(IV) and V(V) species in concentrated sulfuric acid solutions were determined from their diffusion limited current densities on a rotating platinum disk electrode and the solution viscosity. In addition, V(IV) and V(V) species were estimated based on their solubility, UV-Vis spectra, and cyclic voltammetric data. The possible ion-pair formation of V(IV) cation with SO₄²⁻ and/or HSO₄⁻ and the spontaneous polymerization of V(V) at a low H₂SO₄ concentration were discussed.     

Affinity selection of a camelized V(H) domain antibody inhibitor of hepatitis C virus NS3 protease

The HCV genome encodes, within the NS3 gene, a serine protease whose activity specifically cleaves the viral polyprotein precursor. Proteolytic processing of HCV polyprotein precursor by the viral NS3 proteinase is essential for virion maturation and designing specific inhibitors of this protease as possible anti-viral agents is a desirable and practical objective. With a view to studying both the function of HCV NS3 protease and to designing inhibitors of this enzyme, we directed our interest towards engineering macromolecular inhibitors of the viral protease catalytic activity. We describe here the affinity-selection and biochemical characterization of one inhibitor, cV(H)E2, a 'camelized' variable domain antibody fragment, isolated from a phage displayed synthetic repertoire, which is a potent and selective inhibitor of proteolysis by the NS3 enzyme. In addition to being useful as a biological probe to study the function of HCV protease, this inhibitor can serve as a potential pharmacophore model to design antivirals. Moreover, the results suggest a way of engineering improved human-derived small recognition units tailored for enzyme inhibition.      

洗涤剂与洗涤科普知识讲座（五）

本文选自中国洗涤用品工业协会组织编写的《洗涤剂与健康生活》。其主要读者对象为广大洗涤剂消费者，也可供洗涤剂行业的生产、科研、营销、管理人员及大、中专院校师生参考。该书由北京科学技术出版社出版，全国各地新华书店经销。     

Tetrahydrogendecavanadate(V) and its binding to glycylglycine

An adduct between the tetrahydrogen form of decavanadate H₄V₁₀O₂₈²⁻ and glycylglycine, with the stoichiometry Rb₂H₄V₁₀O₂₈·2Gly-Gly·2H₂O, has been isolated and fully characterized. The crystal structure has been determined by X-ray diffraction data. The four hydrogen atoms of the polyvanadate framework could not be located directly, but structural features suggest strongly that they are associated with two triply bridging and two doubly bridging oxygens atoms. Two dipeptide molecules interact with the decavanadate polyanion via a hydrogen bond between O atoms of the carboxylic groups and a couple of doubly bridging surface atoms, which act as acceptors. In addition, there are hydrogen bonding contacts in which the nitrogen atoms and the carbonyl oxygen of the dipeptide molecules take part. IR spectroscopy proved useful in establishing the protonation state of Gly-Gly.     

Growth rate,yield and nitrogen uptake response of grain sorghum (Sorghum bicolor (L) Moench) to nitrogen rates in humid subtropics

Field experiments were conducted during wet seasons (June to October) of 1974, 1976 and 1977 to determine the response of newly developed hybrids and varieties of grain sorghum to N fertilization under humid subtropical conditions of Pantnagar in India. In addition to the enhancement in flowering and maturity stages brought about by N application, it also resulted in increased plant dry weight, translocation coefficients, grain yield plant^–1 and grain yield ha^–1. Varietal differences existed with respect to their responses for yield and N uptake to N rates. Most of the entries responded up to 120 kg N ha^–1. Hybrid CSH 5 utilized applied N more efficiently than other varieties.Publication No 1612 of GBPUA and T, Experiment Station, Pantnagar.     

Direct reduction of As(V) physically attached to a graphite electrode mediated by Fe(III)

As(V) is electrochemically reduced on the surface of a carbonaceous electrode in the presence of hematite and hydrochloric acid 1 M. The influence of other iron oxides (goethite and limonite) was also tested, although they did not provided better results. The potential required to achieve the reduction must be lower than −0.3 V. The anodic voltammograms exhibit a peak at 0.14 V which corresponds to the oxidation of the As° previously generated during the pre-treatment step (−1 V, 5 s) to As(III). Fe(II) generated during the pre-treatment step plays a relevant role in the final reduction to As° which is subsequently reoxidized to As(III) in the anodic scan. This has been applied to the direct detection of 5 mg kg⁻¹ of arsenic in a solid sample of compost with high concentration of iron oxides by square wave voltammetry.     

Bonding of rhenium(V) to diethylenetriaminepentaacetate functional groups of a polymethacrylate support

The bonding of rhenium to diethylenetriaminepentaacetic acid functional groups of a polymeric methacrylate matrix was studied. Diamagnetic complexes were formed of Re(V) with the heterogeneous coordination sphere containing atoms of chlorine and multiply bonded oxygen in addition to carboxylic groups, which are the only groups of the polymeric support functioning as ligands in the bonding to the metal. The rhenium complexes were examined by IR and UV-VIS spectroscopy and by magnetic moment measurements.     

A high output power (70 V, 1.5 A) potentiostat-galvanostat

The design of a high-power potentiostat-galvanostat is presented. This instrument is capable of driving a cell within the rectangular region 0 to ± 72 V and 0 to ± 1.5 A. The anodic oxidation of titanium in acidic medium is given as an example of its application.     

Thermolytic conversion of a bis(alkoxy)tris(siloxy)tantalum(V) single-source molecular precursor to catalytic tantala–silica materials

The new complex (ⁱPrO)₂Ta[OSi(O ^tBu)₃]₃ (1) was prepared via silanolysis of Ta(O ⁱPr)₅ with (^tBuO)₃SiOH and is a useful structural and spectroscopic (NMR, FTIR) model of Ta(V) on silica. The complex was also used to prepare tantalum-containing silica materials, via the thermolytic molecular precursor method (yielding Ta₂O₅ ⋅ 6SiO₂ and Ta₂O₅ ⋅ 18SiO₂) or by grafting 1 onto mesoporous SBA-15 silica (yielding a surface-supported tantala species, TaSBA-15). The solution phase thermolysis of 1 in nonpolar media afforded homogeneous, high-surface-area (ca. 450 m² g⁻¹) xerogels (Ta₂O₅ ⋅ 6SiO₂) that are amorphous up to approximately 1100 °C. A more silica-rich tantala–silica material (Ta₂O₅ ⋅ 18SiO₂) was prepared via a solution-phase co-thermolytic route with 1 and HOSi(O ^tBu)₃, to yield a material with a Si/Ta ratio of 9/1. It was demonstrated that tantala–silica materials are active as catalysts for cyclohexene oxidation.     

Effect of crop residues on grain yield response of sorghum (t Sorghum bicolor) (L.) to application of N and P fertilizer

A field experiment was conducted on two soil types for seven years (1988–1994) to investigate the effect of the presence of crop residue on grain yield response of sorghum to NP fertilizer applied every year or once only at the start of the experiment. Grain yield was increased by the NP fertilizer alone, but was not further significantly increased by application of both residues and NP fertilizer. During the study period yields decreased abruptly with decreasing rainfall after the first year particularly on the Typic Pellustert. Thus there was a difference according to soil type. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrocatalytic oxidation of As(III) to As(V) using noble metal-polymer nanocomposites

Nanocomposite materials synthesized by incorporation of Pt⁰ and Pd⁰ nanoparticles into a poly(pyrrole-alkylammonium) matrix have been characterized by transmission electron microscopy. These nanocomposites coated onto carbon electrodes present strong electrocatalytic properties towards the oxidation of arsenite to arsenate. Nanocomposite films modified electrodes have been used for As(III) analysis, with a detection limit reaching 2.4 μM (0.17 ppm). The interest of these nanocomposite electrode materials deposited onto carbon felt macroelectrodes for the exhaustive electrocatalytic oxidation of As(III) to As(V) solutions was also demonstrated. The use of a water-soluble poly(quaternary ammonium) salt acting both as supporting electrolyte and as extracting agent allowed us to efficiently remove the electrocatalytically generated arsenic(V) species by liquid phase polymer-assisted retention (LPR) technique.     

Functional water-insoluble polymers with ability to remove arsenic(V)

Three resins were synthesized through radical polymerization: poly[(ar-vinylbenzyl)trimethylammonium chloride] P(VBTA), poly[(ar-vinylbenzyl)trimethylammonium chloride-co-acryloylmorpholine] P(VBTA-co-AM), and poly[(2-acryloyloxy) ethyltrimethylammonium chloride-co-acryloylmorpholine]. The removal capacity for arsenic under different conditions was studied and compared with a commercial resin Amberlite IRA 400-Cl. The arsenic sorption capacity of the resins at the optimum pH showed the following order: Amberlite 95.5% (27.1 mg/g, 0.36 mmol/g), P(VBTA) 92.6% (16.3 mg/g, 0.22 mol/g), P(VBT-co-AM) 90.4% (21.5 mg/g, 0.29 mmol/g), and P(AETA-co-AM) 87.3% (21.7 mmg/g, 0.29 mmol/g).     

Visible-light photolysis of corrole-manganese(IV) nitrites to generate corrole-manganese(V)-oxo complexes

Photolysis of highly photo-labile corrole-manganese(IV) nitrites by visible light was studied in three corrole systems with different electronic environments. As observed in all three systems, homolytic cleavage of ON bond of nitrite ligand resulted in one-electron photo-oxidation to generate manganese(V)-oxo corroles, as determined by their distinct UV–vis spectra and kinetic behaviors. The spectral and kinetic results are rationalized by a multiple oxidation model, where the electron-demand Mn^V-oxo species may serve as direct two-electron oxidant for oxygen atom transfer reactions and less electron-demand systems undergo a disproportionation reaction to form a putative manganese(VI)-oxo corrole as the true oxidant.     

C4和C5回炼对提高甲醇制烯烃(MTO)收率的研究

甲醇制烯烃(MTO)装置使用的催化剂SAPO-34分子筛具有较强的酸性催化特征,利用该性质对C_4和C_5进行裂解实验,文中通过实验得出在甲醇制烯烃催化剂的作用下能够部分裂解C_4和C_5,裂解产物中有目的产物质量分数约25%,不同的再生定碳对C_4和C_5的裂解程度也有差异,当再生催化剂定碳控制在1.3%—1.6%时,C_4和C_5的裂解程度最优。C_5回炼时,乙烯和丙烯的收率能提高0.49%;同时,未反应的C_4/C_5进入反应器后抑制了甲醇制烯烃反应中C_4/C_5的生成,进一步提高烯烃的收率。     

As(V) removal using a magnetic layered double hydroxide composite

The Mg–Fe–Zr layered double hydroxide/Fe₃O₄ composite was synthesized by co-precipitation of layered double hydroxide (LDH) precursors in the presence of Fe₃O₄ particles and its arsenic adsorption behavior was investigated. The material characterization by XRD, TEM, surface area analysis, SEM-EDX, and VSM revealed that the composite was comprised of Fe₃O₄ particles covered by an LDH. The As(V) adsorption capacity of the composite (188 mg/g) was achieved at pH 3. The kinetics studies and adsorption isotherms suggested a two-stepped adsorption mechanism of the monolayer adsorption inside the interlayers of LDH.