Chemical and immunochemical investigation of the lipopolysaccharides ofVibrio alginolyticus

A chemical and immunochemical study of the LPSs of the microorganismsVibrio alginolyticus (strains 1385–80, 945–80, and 2076–80) has been made. A difference in the monosaccharide composition of the LPSs of the strains studied has been shown. It had been established that the LPSs of strains 945–80 and 2076–80 possess a high serological specificity, while the LPS of strain 1385–80 differ serologically from them. A suggestion is made of the role of different monosaccharides in the formation of the immunochemical determinants of the LPSs of the strains studied.Pacific Ocean Institute of Bioorganic Chemistry of the Far-Eastern Scientific Center of the USSR Academy of Sciences, Vladivostok. Translated from Khimiya Priorodnykh Soedinenii, No. 5, pp. 652–657, September–October, 1987.     

Lipids and lipopolysaccharides of the genusFlavobacterium

The fatty acid compositions of the free lipids of three strains and the monosaccharide compositions of the lipopolysaccharides of four strains of new species of microorganisms of the genusFlavobacterium have been studied. The acidic nature of the polysaccharides of the LPSs of the microorganisms studied has been shown.     

Lipids and lipopolysaccharides of the genusFlavobacterium

The fatty acid compositions of the free lipids of three strains and the monosaccharide compositions of the lipopolysaccharides of four strains of new species of microorganisms of the genusFlavobacterium have been studied. The acidic nature of the polysaccharides of the LPSs of the microorganisms studied has been shown.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center of the USSR Academy of Sciences, Vladivostok, and Institute of Microbiology of the USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 564–567, September–October, 1986.     

Immunochemical study of the products of the biological activity of protein nature in the medium after the cultivation ofYersinia pseudotuberculosis as a function of the temperature

An immunochemical investigation has been made of the culture liquid after the cultivation of ten strains of the microorganisms Yersinia pseudotuberculosis. It has been shown that in the process of vital activity all the strains investigated, to a greater or smaller degree, produce into the culture medium products of catabolic breakdown consisting of fragments of receptor proteins which are possibly, regulators of metabolic processes taking place under the influence of the constantly changing conditions of the growth medium.     

Synthesis and anticholinesterase activities of O-phosphorylated derivatives ofd-allylpseudoephedrine

An immunochemical investigation has been made of the culture liquid after the cultivation of ten strains of the microorganisms Yersinia pseudotuberculosis. It has been shown that in the process of vital activity all the strains investigated, to a greater or smaller degree, produce into the culture medium products of catabolic breakdown consisting of fragments of receptor proteins which are possibly, regulators of metabolic processes taking place under the influence of the constantly changing conditions of the growth medium.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 436–439, May–June, 1993.     

Mass‐Spectrometric Studies of Providencia SR‐Form Lipopolysaccharides and Elucidation of the Biological Repeating Unit Structure of Providencia rustigianii O14‐Polysaccharide

Enterobacteria Providencia are opportunistic human pathogens causing multiple types of infections. Earlier we have studied the S‐ and R‐form lipopolysaccharides (LPSs) of Providencia strains of various O‐serogroups and established the structures of the O‐polysaccharides (O‐antigens) and core‐region oligosaccharides, respectively. Now we report on mass spectrometric studies of oligosaccharides consisting of the core moiety with one O‐polysaccharide repeating unit attached, which were derived from the SR‐form LPSs of Providencia strains. The site of attachment of the O‐polysaccharide to the core and the structure of the O‐polysaccharide biological repeating unit were elucidated in Providencia rustigianii O14 using NMR spectroscopy.     

The nature of active centers in cyclotrimerization of isocyanates catalyzed by the tertiary amine—α-oxide—proton donor system 1. The role of the proton donor

The rate of cyclotrimerization of phenyl isocyanate in chlorobenzene at 120 °C in the presence of the tertiary amine--oxide-proton donor (PD) ternary catalytic system has been studied using a dual calorimeter and a series of phenols with various acidities as the PD. In the presence of weakly acidic phenols, complexes of quaternary ammonium type bases are formed in the ternary catalytic systems. Acidic phenols afford salt complexes with the transfer or a proton from phenol to the tertiary amine in a quantitative yield, while the -oxide present remains unaffected. The structures of the complexes were studied by IR and by IR and¹H NMR spectroscopy.DeceasedTranslated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1382–1385, lune, 1996.     

Structure and serology of O-antigens of nitrogen-fixing rhizobacteria of the genus <Emphasis Type="Italic">Azospirillum</Emphasis>

The review presents a discussion of the published data of 2002 to 2014 dealing with structural studies of O-specific polysaccharides, representatives of the Azospirillum diazotrophic rhizobacteria, summarizing the results of a series of authors´ studies. Some general structures incorporated in O-specific polysaccharides responsible for classification of bacterial cultures into serogroups on the basis of immunochemical studies were characterized. The structures of O-specific polysaccharides of seven azospirillum strains identical to those of previously studied strains are presented in this review for the first time.     

Structural variability of endotoxins from R-type isogenic mutants of Shigella sonnei

The structural variations in the rough-type endotoxins [lipopolysaccharides (LPSs)] of Shigella sonnei mutant strains (S. sonnei phase II-4303, R41, 562H and 4350) were investigated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem MS. A series of S. sonnei mutants had previously been the subject of analytical studies on the biosynthesis of heptose components in the core oligosaccharide region of LPSs. This study gives a complete overview on the structures of the full core and lipid A of S. sonnei mutant strains by MS. We found that the LPSs of the isogenic rough mutants were formed in a step-like manner containing 0:1:2:3 heptose in the deep core region of 4350, 562H, R41 and 4303, respectively, and the longest LPS from the mutant S. sonnei 4303 contained also five hexoses. The structural variations in the lipid A moiety and in the oligosaccharide part of the intact LPS were followed by MALDI-TOF-MS/MS. For the dissolution and the ionization of the samples, 2,5-dihydroxybenzoic acid in citric acid solution was applied as matrix. The detailed evaluation of the mass spectra indicates heterogeneity in the lipid part due to the differences in the phosphate and fatty acid composition.     

Microbial biotransformations in water/organic solvent system. Enantioselective reduction of aromatic β- and γ-nitroketones

The production of single enantiomers of γ- and β-nitroalcohols by microbial bioreduction has been studied. A restricted screening among 14 yeasts was performed using 1-phenyl-4-nitro-1-butanone 1 as substrate. Pichia minuta (CBS 1708) and Pichia etchellsii (CBS 2011) gave the highest enantiopreference for (S)-alcohol 3 formation (e.e. 85% and 80%, respectively), while Kluyveromyces marxianus (CBS 397) was the only strain able to preferentially furnish the (R) enantiomer (e.e. 70%). These three microorganisms, along with baker's yeast, were then employed in reactions performed in water/organic solvent systems using different solvents (hexane, benzene and dibutyl ether) affording alcohol 3 in high enantiomeric excesses (>95–97%). These strains were also employed to reduce 1-phenyl-3-nitro-1-propanone 2, maintaning the same stereobias observed with γ-nitroketone 1 and showing high enantioselectivity in both simple aqueous (>85–97%) and biphasic media (>97%).     

Spectroscopic investigations and structural confirmation studies on thiourea

The Fourier transform infrared and Raman spectra of thiourea have been studied in the region 4000–400 and 4000–10 cm^?1, respectively. A complete vibrational analysis on the molecular structure of thiourea has been made on the basis of C_2υ point group symmetry. The validity of the vibrational assignments on the structure of thiourea is supported by evaluating the molecular constants and the potential energy distribution.     

Neutron diffraction study of the deuterides of the over-stoichiometric compounds LaNi5+x

The deuterides of three intermetallic compounds LaNi_5+x with x=0, 0.2 and 0.4 have been prepared and analyzed by neutron powder diffraction at two different deuterium concentrations. On one hand, the crystallographic properties of the α and the β phases have been studied with the two phases in equilibrium on the pressure plateau characteristic for the phase transition. On the other hand, the β phase has been studied as a single phase in the solid solution domain. Crystal structures were refined using the Rietveld method. Crystal symmetry, lattice parameters and deuterium sites and occupancy parameters are reported for all the different phases. Anisotropic line profile analysis has been used to characterize the strains induced by deuterium absorption in the various regions of the Pressure–Composition–Isotherm curves. Results are compared for the different values of x and related to the cycle life properties for each compound.     

Highly stereoselective synthesis of a sex pheromone of the dry bean beetleCallosobruchus analis

Total synthesis of 3-methylhept-2(Z)-enoic acid, a sex pheromone of the dry bean beetleCallosobruchus analis, has been performed using a previously developed highly stereoselective method of the construction of disubstituted (Z)-methylolefins based on the higher thermodynamic stability of (E)-isomers of α,β-disubstituted acroleins. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1385–1388, July, 1999.     

Identification of Flavobacterium strains by gas liquid chromatographic analysis of volatile fatty acids produced in culture

The classification previously established for 74 Flavobacterium strains by gas liquid chromatographic (GLC) analysis of volatile fatty acids (VFA) produced in culture allowed the recovery of 9 groups (J. gen. Microbiol., 1986, 132, 2723–2732). Since graphic representation of the strains based on the first 3 factors obtained by principal component analysis (PCA) clearly separated these groups, we tried to identify 80 new strains by comparing their positions with those of the 9 groups, on the basis of both hierarchical classification and PCA methods. Of the 153 strains studied, only 12 were not allocated to a group corresponding to their original biochemical identification Thus, on the whole, this characterization method by GLC analysis seemed satisfactory, although it could not be established whether the method was adequate for routine identification, or would serve merely as a complement.     

Flow-Injection Enzyme Immunoassay for Human IgG by Using Enhanced Chemiluminescence Reaction for Horseradish Peroxidase Label Quantitation

Abstract

A flow-injection sandwich enzyme immunoassay for human IgG as model antigen by using horseradish peroxidase as label, polystyrene beads as solid support, and the enhanced chemiluminescence reaction for peroxidase quantitation is described. the kinetics of antigen—immobilized antibody interaction has been studied and the quantitative time-concentration ranges of reactions have been estimated. Each of the two immunochemical steps of analysis have been pursued in the kinetic regime. the time for each immunochemical step was reduced to 2–3 min. the enhanced luminescent reaction involving luminol and p-iodophenol as substrates was used to detect the peroxidase label. the conditions for chemiluminescent reaction were optimized. the detection limit for peroxidase in a 3 min assay was 5–10^?16 moles/tube. the detection limit for IgG, in the developed immunoassay, is 10^?9 M, the overall time of the assay being 5–10 min.     

New insights into the bioactivity of SiO2–CaO and SiO2–CaO–P2O5 sol–gel glasses by molecular dynamics simulations

The structures of binary xCaO · (100 ? x)SiO₂ glasses with x = 10, 20 and 30 mol-% and ternary (20 ? x)CaO · xP₂O₅ · 80SiO₂ glasses with x = 3, 10, 15, 17 and 20 mol-% have been studied by means of classical molecular dynamics simulations using both the melt-quenched and the sol–gel protocols. The structural picture derived correlates the bioactive behaviour to the combined effects of the connectivity of the extended silicate network and to the tendency to form (or not to form) non-homogeneous domains. In this context, a mathematical relationship that relates the Ca/P ratio in the Ca phosphate micro-segregation zones to the P₂O₅ content in ternary glasses has been developed and this has been used to fine-tuning the optimum amount of P in a glass for its highest in vitro bioactivity. The composition with optimal Ca/P ratio, 80Si–14.8Ca–5.2P, has been synthesized and the results of bioactivity tests have confirmed the prediction.     

Microstructural,magnetic and crystal field investigations of nanocrystalline Dy3+ doped zinc oxide

Dy³⁺ doped zinc oxide was prepared by co-precipitation method. The as-prepared samples were annealed at different temperatures to obtain the samples with different particle sizes. The crystallographic phases of all the samples were confirmed by X-ray diffraction (XRD) patterns. Rietveld analysis of the XRD pattern of the sample annealed at 80 °C showed that most of the Dy³⁺ ions were substituted in the Zn²⁺ site of the hexagonal ZnO lattice. But in case of samples annealed at higher temperatures, a fraction of Dy³⁺ ions comes out from the ZnO lattice and this fraction increases with the increase of annealing temperature. The sizes of nanoparticles and the lattice strains of all the samples were obtained from the Hall–Williamson plot. High resolution transmission electron microscopy showed that ZnO nanoparticles are more or less spherical. Magnetic susceptibilities (χ) of some selected samples measured in the temperature range of 300–14 K indicate that the samples are paramagnetic. Values of χ were successfully fitted by Curie–Weiss law. A good theoretical simulation of χ of the sample annealed at 80 °C has been achieved using the one-electron crystal field interaction of the Dy³⁺ ions with its diamagnetic neighbors in the hexagonal single crystal.     

Study of ageing of ketone resins used as picture varnishes by pyrolysis–silylation–gas chromatography–mass spectrometry

This contribution presents a research aimed at the study of the commercial products Laropal K80, Keton N and MS2A, ascribed to ketone resins prepared as thin films, in an attempt to reproduce the pictorial layers and protective finishes that are commonplace in contemporary paintings. For this purpose, a new method based on “online” silylation–pyrolysis using hexamethyldisilazane as a derivatisation reagent in pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) has been proposed. This procedure leads to the unambiguous identification of such varnishes and improves direct Py–GC–MS. Chemical changes due to the degradation effect of environmental agents have been especially considered. To that end, three different accelerated ageing processes were applied to a series of specimens prepared from the studied commercial products: thermal, UV light and ageing in an SO₂-polluted chamber. Chemical changes due to UV light ageing of Keton N resin are in good agreement with those previously reported in the literature.     

Lipopolysaccharides from Serratia marcescens possess one or two 4-amino-4-deoxy-L-arabinopyranose 1-phosphate residues in the lipid A and D-glycero-D-talo-oct-2-ulopyranosonic acid in the inner core region

The carbohydrate backbones of the core-lipid A region were characterized from the lipopolysaccharides (LPSs) of Serratia marcescens strains 111R (a rough mutant strain of serotype O29) and IFO 3735 (a smooth strain not serologically characterized but possessing the O-chain structure of serotype O19). The LPSs were degraded either by mild hydrazinolysis (de-O-acylation) and hot 4 M KOH (de-N-acylation), or by hydrolysis in 2 % aqueous acetic acid, or by deamination. Oligosaccharide phosphates were isolated by high-performance anion-exchange chromatography. Through the use of compositional analysis, electrospray ionization Fourier transform mass spectrometry, and 1H and 13C NMR spectroscopy applying various one- and two-dimensional experiments, we identified the structures of the carbohydrate backbones that contained D-glycero-D-talo-oct-2-ulopyranosonic acid and 4-amino-4-deoxy-L-arabinose 1-phosphate residues. We also identified some truncated structures for both strains. All sugars were D-configured pyranoses and alpha-linked, except where stated otherwise.     

Extension of elastic liquids: Polyisobutylene

An apparatus is described and a method discussed for determining the rheological characteristics of elastic liquids during extension at constant rates of deformation and extension. The material studied was polyisobutylene of molecular weight 7 × 10⁴. At low constant deformation rates steady-flow regimes were achieved, with corresponding equilibrium high elastic strains. A detailed study has been made of the process of attainment of steady-flow regimes and it is shown that before steady flow is reached the curve of longitudinal viscosity versus strain passes through a maximum. As the rate of deformation rises, the strains at which steady–state flow regimes are achieved increase, and the time required to reach these regimes decreases. Qualitatively this occurs in the same way as upon shear. The dependence of equilibrium high-elastic strains (under steady-flow regimes) on the rate of deformation has been determined. At steady-flow regimes the stress depends linearly on the rate of deformation at low values of the stress. Under such conditions Trouton's formula is valid. At constant rates of extension the stress versus time curve passes through a maximum which becomes higher with increasing extension rates.