Two-dimensional polyacrylamide gel electrophoresis, with immobilized pH gradients in the first dimension, of barley seed proteins: discrimination of cultivars with different malting grades.

The suitability of high-resolution two-dimensional gel electrophoresis for barley cultivar discrimination and for classification with respect to their malting properties was studied. Seed proteins of 14 barley cultivars with different malting qualities were extracted with urea/dithiothreitol/Nonidet P-40 buffer and subjected to two-dimensional gel electrophoresis with immobilized pH gradients in the first dimension (IPG-DALT). The results of IPG-DALT were compared to the protein patterns obtained by a standard technique, sodium dodecyl sulfate polyacrylamide gel electrophoresis of hordeins. Sodium dodecyl sulfate-gel electrophoresis yielded seven different "B" and four different "C" hordein patterns; "A" and "D" hordein patterns were uniform in all cultivars tested. Four cultivars could be distinguished unequivocally, the others were classified into three groups containing between two and five cultivars. In contrast to these findings. IPG-DALT yielded three different "A", eight different "B", four different "C" and two different "D" hordein patterns. When the "A", "B", "C" and "D" hordein patterns were combined, ten cultivars exhibited unique hordein patterns whereas the remaining ones were classified into two groups containing two cultivars each. Moreover, when albumin and globulin proteins were used for evaluation in addition to the hordeins, all cultivars could be discriminated by IPG-DALT. IPG-DALT, performed on small-scale and/or ready-made gels, proved to be an ideal complementary system to one-dimensional electrophoretic methods for routine seed testing purposes because of its speed, reliability, and simplicity. IPG-DALT was also applied to study the relationship between the different polypeptide patterns and the malting quality. Although cultivars with identical one-dimensional protein patterns but different malting quality could be successfully differentiated by IPG-DALT, a direct correlation between specific protein spots or protein patterns to the malting quality was not found within the cultivars tested.     

Synthesis and transformations of 1-(4-hydroxyphenyl)dihydrouracils

N-(4-Hydroxyphenyl)--alanine and its methyl derivatives, as well as p-hydroxyphenylamino-, '-dipropionic acid, were obtained by the reaction of p-aminophenol with methyl acrylate and acrylic, methacrylic, and crotonic acids. The -alanines were converted to the corresponding hydrazides and 1-(4-hydroxyphenyl)dihydro- and thiodihydrouracils, which were decyclized by the action of alkalis to ureido and thioureido acids and were dehydrogenated by heating with sulfur to give uracils. The dihydro- and thiodihydrouracils were alkylated and acetylated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1406, October, 1982.     

(p, Vm, T) measurements of (cyclohexane + nonane) at temperatures from 298.15 K to 328.15 K and at pressures up to 40 MPa

The densities and speeds of sound of (cyclohexane + nonane) were measured at four temperatures from 298.15 K to 328.15 K, and the respective values of excess volumes and adiabatic compressibility were calculated. Thereafter, the densities for the last system were measured at elevated pressures (0.1 to 40) MPa at four temperatures over the range 298.15 K to 328.15 K with a high-pressure apparatus. The high-pressure density data were fitted to the Tait equation and the isothermal compressibilities were calculated with a novel procedure with the aid of this equation. The low- and high-pressure values of calculated from the density data show that the deviations from ideal behaviour in the system decrease slightly as the temperature and pressure are raised. The data were fitted to the fourth-order Redlich-Kister equation, with the maximum likelihood principle being applied for the determination of the adjustable parameters.     

Molecular modeling study of the differential ligand–receptor interaction at the μ, δ and κ opioid receptors

3D models of the opioid receptors , and were constructed using BUNDLE, an in-house program to build de novo models of G-protein coupled receptors at the atomic level. Once the three opioid receptors were constructed and before any energy refinement, models were assessed for their compatibility with the results available from point-site mutations carried out on these receptors. In a subsequent step, three selective antagonists to each of three receptors (naltrindole, naltrexone and nor-binaltorphamine) were docked onto each of the three receptors and subsequently energy minimized. The nine resulting complexes were checked for their ability to explain known results of structure-activity studies. Once the models were validated, analysis of the distances between different residues of the receptors and the ligands were computed. This analysis permitted us to identify key residues tentatively involved in direct interaction with the ligand.     

EVIDENCE FOR BRANCHING IN THE PHOTOCYCLE OF BACTERIORHODOPSIN AND CONCENTRATION CHANGES OF LATE INTERMEDIATE FORMS

Abstract— Flash photolysis transients of bacteriorhodopsin were recorded with a spectrograph -multielement photodiode array combination and the recordings were analyzed to determine the concentrations of bacteriorhodopsin intermediates "M" and "O" relative to the amount of "bR" cycling (pH 7.1,10–40°C). Estimated concentration time courses were simulated with solutions to two kinetic decay models which could account for photocycle temperature dependence. A unidirectional unbranched decay model overpredicts our estimated levels of [O(r)], whereas a model branched at the "M" intermediate describes each of the later intermediate levels well (with no evidence for an independent "N" form). Our results are consistent with "M" decay regulating the level and rates of change of [bR (t)] and (bR(f)]- and also suggest that two temperature-dependent pathways form "bR" from "M", one directly, and the other indirectly through "O".     

Identifying the mechanisms of polymer friction through molecular dynamics simulation

Mechanisms governing the tribological behavior of polymer-on-polymer sliding were investigated by molecular dynamics simulations. Three main mechanisms governing frictional behavior were identified. Interfacial "brushing" of molecular chain ends over one another was observed as the key contribution to frictional forces. With an increase of the sliding speed, fluctuations in frictional forces reduced in both magnitude and periodicity, leading to dynamic frictional behavior. While "brushing" remained prevalent, two additional irreversible mechanisms, "combing" and "chain scission", of molecular chains were observed when the interfaces were significantly diffused.     

反相高效液相色谱法测定3种中成药中的葛根素

 建立了测定小儿清感灵片、步长新脑心通胶囊和感冒清热颗粒 3种中成药中葛根素含量的反相高效液相色谱方法。采用APEXODS色谱柱 ,以醋酸铵缓冲液 (10 0mmol/L ,pH 5 0 ) 甲醇 (体积比为 75∶2 5 )的混合溶液为流动相 ,检测波长为 2 5 0nm ,流速为 0 8mL/min。葛根素在 2mg/L～ 2 0mg/L时其色谱峰面积与质量浓度的线性关系良好 (r =0 9999) ;上述 3种中成药中的葛根素含量分别为 3 48mg/g ,1 0 8mg/ g及 1 5 2mg/ g(蔗糖型 ) ;其加样回收率分别为 99 0 % ,93 4%和 97 5 %。该法简便、快速、专属性强 ,可以作为多种中药制剂中葛根素含量的测定方法。     

Immobilization of Mercuric reductase from aPseudomonas putida strain on different activated carriers

Mercuric reductase was isolated fromPseudomonas putida KT2442::mer-73 and immobilized on Chromatographic carriers activated by various methods. The immobilization methods for covalent coupling were compared with regard to preservation of enzymatic activity and coupling yields. Highest yields were obtained with carriers bearing the most reactive functional groups. Best results were achieved with tresyl chloride-activated carriers. The optimum binding conditions were found at pH 8. Application of the immobilized mercuric reductase for continuous treatment of Hg(II)-containing water was examined in a fixed bed reactor. Space-time yields up to 510 nmol/min-mL were attained. The kinetics of immobilized enzyme systems were not diffusion-controlled.     

Complex formation between polyethylene oxide-containing nonionic surfactants and α- and β-cyclodextrins

The inclusion complexes based on polyethylene oxide (PEO)-containing nonionic surfactants and ()-cyclodextrins (CD) were synthesized. Their composition and crystal structure were studied. The inclusion complexes of the surfactants with -CD form a crystal structure similar to that of the -CD—PEO complex. The inclusion complexes of the nonionic surfactants with -CD form a structure similar to that of the -CD—PEO complex. The structural models of the crystalline complexes were proposed. The micelle-forming abilities of the surfactants in dilute solutions in the presence of CD were studied. The CD binding to a surfactant molecule in aqueous solutions begins from the PEO fragment. Possible reasons for the formation of inclusion complexes between noncomplementary surfactant and -CD molecules were discussed. The thermal stability was studied, and the possibility of thermal dissociation of the pseudo-complementary -CD—surfactant complexes was shown.     

Isoquinoline derivatives

1-(3,4-Dimethoxyphenyl)-1-aminomethylcyclopentane (IV) was condensed with substituted phenylacetyl and benzpyl chlorides to synthesize 1-[R,R,R-phenylacet(benz)amidomethyl]-1-(3,4-dimethoxyphenyl)cyclopentanes (VI), which were converted to 1-[R,R,R-phenyl(benzyl)]-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-4-spirocyclopentanes (IX) by cyclization and subsequent reduction. Reduction of VI yielded the corresponding secondary amines (VII). The compounds obtained were subjected to Chromatographic analysis. The IR spectra were investigated. Compounds VII and IX were subjected to pharmacological testing.See [6] for communication IV.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 637–640, May, 1971.     

Preparation and characterization of Mg(II)-, Ca(II) and Cd(II) complexes of 1,2-ethanediol and water

Mixed ligand complexes of different compositions were prepared with water, sulfate ion and 1,2-ethanediol as ligand. IR spectra and the thermoanalytical curves of the complexes were recorded. Oxygen atoms bound by one or two coordinate bonds to the metal ion, or by hydrogen-bonds in the crystal, were observed. As for the water molecule, 1,2-ethanediol molecules of crystal and monohydrate type were found, depending on the type of binding of the oxygen atoms.This revised version was published online in November 2005 with corrections to the Cover Date.     

Complexation of Vinpocetine with Cyclodextrins in the Presence or Absence of Polymers. Binary and Ternary Complexes Preparation and Characterization

Inclusion complexation between -cyclodextrin (-CD),hydroxypropyl--cyclodextrin (HP--CD), water-solublepolymers (PVP and HPMC) and vinpocetine was studied in aqueous solution and in the solid state.Phase solubility studies were used to evaluate the complexation in aqueous solution at roomtemperature. Stability constants (K_c) of binary and ternary complexes were determined spectrophotometrically. Differential scanning calorimetry (DSC)was used to characterize kneaded, co-evaporated and lyophilised binary and ternary systems.The K_c values obtained were 70.14 M^-1 and 35.01 M^-1 for vinpocetine--CD and vinpocetine-HP--CD and increased in a range of 17% to 94%by addition of water-soluble polymers. Some preliminary evidences ofinclusion complexation were obtained from DSC suggesting that co-evaporated and lyophilised binary andternary systems were truly inclusion complexes.     

New designs for inhibitors of the NF-κB: DNA binding

We present a series of new inhibitors of the association between nuclear factor kappa B (NF-B) and the corresponding B site in DNA. They were designed using the lead compound 15-deoxy-^12,14 -prostaglandin J₂ (PGJ2), which is a natural product with demonstrated inhibitory efficiency for this system. First, the binding mode of PGJ2 to NF-B was unraveled by GOLD docking calculation. Subsequently, substitutions were made to PGJ2 to optimize its association with NF-B. Care was taken not to strongly increase the reactivity of the new compounds, and to keep the overall shape, size and hydrophilicity of the lead compound, which should render them a similar bioavailability. Molecular mechanics calculations were performed to decide on the suitability of the substitutions, and to evaluate the energies of association with NF-B. Density functional theory calculations were performed also to study the overall reactivity of the substituted drugs towards NF-B. Important general conclusions were obtained, concerning the improvement of these natural inhibitors; namely, a set of rational methodologies were deduced to improve the association between the PGJ2 derivatives and NF-B, and their efficiency demonstrated by generating a set of substituted complexes, some of them with a very much increased affinity for NF-B, opening new doors to enlarge the therapeutic capabilities of this class of drugs.     

Use of a Packed Minicolumn Connected to a Syringe for Determination of Trace Elements in Biological and Water Samples by Flame Atomic Absorption Spectrometry

In this study, a syringe-connected minicolumn resin was used for the separation and enrichment of cadmium, copper, nickel and zinc prior to their determination by flame atomic absorption spectrometry. The proposed technique was compared with classical batch and column techniques in terms of rapidness, simplicity, enrichment and risk of contamination. The minicolumn was filled with Chromosorb-103 resin and connected to a syringe. If the samples were treated with ammonium pyrrolidine dithiocarbamate or 8-hydroxyquinoline, the analytes were quantitatively retained at pH2 and pH5 on the resin, respectively. On the other hand, if no chelating agent was added, the analytes were quantitatively retained at pH10. The analytes retained by the resin were quantitatively eluted by drawing and discharging nitric acid in acetone. The analytes in spiked river-water samples and in certified standard reference Bovine-Liver (NIST SRM 1577 b) were quantitatively (94%) recovered. The relative standard deviations for the determinations were found to be 1.0–10%.     

Concerning intramolecular transacetalization with the formation of 1,3-dioxanes

Summary 2-Methyl-1,3-dioxanes were isolated when the (-ethoxyethyl) ethers of -hydroxycarbonyl compounds were subjected to the Reformatskii reaction.     

Thermo-responsive interpenetrating polymer networks composed of AAc/AAm/NMA by radiation grafting

Interpenetrating polymer network (IPN) hydrogels were prepared by grafting of acrylamide (AAm), N-methylol acrylamide (NMA) and acrylic acid (AAc) onto preirradiated polypropylene (PP) membrane. To obtain PP-g-AAc/AAm/NMA IPN hydrogels, at first, AAc were grafted onto preirradiated PP and then AAm were grafted onto the PP-g-AAc membranes. Finally NMA were grafted onto PP-g-AAc/AAm membranes. In the different stages of grafting under different reaction conditions, trapped radicals in the membrane samples were probed by electron spin resonance (ESR). The temperature response behaviors of the IPN hydrogels were studied. Reversible behavior and controlled release of drug tests made reflecting the switching to on state at higher temperatures and to off state at lower temperatures were achieved. By increasing the grafted content of NMA, higher transition temperature of the hydrogel could be attained.     

On the applicability of CNDO indices for the prediction of chemical reactivity

A series of CNDO/2 molecular orbital properties were evaluated to determine their utility in parameterizing chemical reactivities. Some of these indices were used previously for only electron methods and were extended here to include the framework. Theoretical rationales were given for this extension to the semi-empirical all valence electron methods. Four systems, the aromatic hydrocarbons, the benzene derivatives, the substituted benzoic acids, and the substituted phenyl amines, were studied to test how well these indices can parameterize chemical reactivities. This study focused on reactions involving both and electrons where the reactive site is not necessarily on the aromatic framework. For the nonplanar and heteropolar systems, these indices performed as well as the Hückel method did for the classical aromatics. These CNDO indices should perform effectively in multivariable regressions to parameterize the reactivities for more complicated problems such as those encountered in quantitative structure activity relationships of drugs.     

Spectral Studies on the Cyclodextrin Inclusion Complexes of Toluidine Blue O and Meldola's Blue in Aqueous Solution

The absorption and emission spectral properties of toluidine blue O (TBO) and Meldola's blue (MDB) in the presence of cyclodextrins (CDs) were studied. Formation of 1 : 1 and 1 : 2 (CD-Dye) inclusion complexes were observed with -CD and -CD, respectively. An increase in the emission intensity was noticed in the presence of -CD due to the formation of 1 : 1 (CD-Dye) inclusion complexes. However, a decrease in the emission intensity was observed in the presence of -CD due to the formation of 1 : 2 (CD-Dye) inclusion complexes. Dimerization of dye molecules in the presence of -CD lead to a decrease in the emission intensity. The formation constants for the 1 : 1 and 1 : 2 (CD-Dye) inclusion complexes were calculated.