Isolation and physico-chemical properties of a protein, included in an endotoxin from Yersinia pseudotuberculosis

A major protein of the endotoxin from Yersinia pseudotuberculosis was isolated from the complex lipid A--protein by treatment with SDS and triton X-100 followed by gel-chromatography on Sephacryl S-300. Protein has apparent molecular mass 40 kDa and alanine as N-terminal amino acid residue. CD and IR spectroscopy conformational changes of the protein molecule in the process of its isolation. The thermal and pH stabilities of the protein were investigated by the methods of intrinsic fluorescence and differential scanning microcalorimetry. The isolated protein revealed two thermal transitions (at 30-35 and 50-55 degrees C), which depend on Ca2+ concentration.     

The structure of O-specific polysaccharide from Yersinia enterocolitica serotype O:6.31 lipopolysaccharide

The serologically active O-specific polysaccharide has been isolated from the lipopolysaccharide of Yersinia enterocolitica, serovar O: 6.31. Using methylation, partial acid hydrolysis and 13C NMR spectroscopy, the main structural moiety of the O-specific polysaccharide is shown to be the following disaccharide repeating unit: (Formula: see text).     

Structural studies on O-specific polysaccharides of lipopolysaccharides from Yersinia enterocolitica serovars O:5 and O:5,27

Lipopolysaccharides of Yersinia enterocolitica serovars O:5 and O:5,27 were shown to have a similar sugar composition, consisting of L-rhamnose, D-glucose, D-galactose, D- and L-glycero-D-manno-heptose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, 3-deoxy-D-manno-octulosonate and D-threo-pent-2-ulose (D-xylulose). Partial hydrolysis of lipopolysaccharides with acetic acid produced rhamnans with the following repeating unit: ----3)-L-Rha rho(alpha 1----3)-L-Rha rho(alpha 1----3)-L-Rha rho(beta 1----. 13C-NMR and methylation studies of the lipopolysaccharides gave the following structure for the repeating unit of the two O-specific polysaccharides: ----3)-L-Rha rho(alpha 1----3)-L-Rha rho(alpha 1----3)-L-Rha rho(beta 1----. (formula; see text)     

Isolation and characterization of lipopolysaccharides from cell walls of blue-green algae of the genus Phormidium.

Lipopolysaccharide (LPS) fractions were isolated from three species of blue-green algae of the genus Phormidium, namely, P. africanum, P. laminosum, and P. uncinatum, by using a phenol-water procedure followed by exhaustive extraction with ammonium oxalate. The materials obtained were shown to be closely related biochemically. Nearly 60% of the LPS consisted of the polysaccharides galactose, glucose, mannose, xylose, arabinose, and rhamnose and an unidentified, fast-moving sugar residue. In addition, glucosamine, galactosamine, and 2-keto-3-deoxyoctonate were detected. Oleic, stearic, and palmitic acids were found in the hydrolysate of the lipid component, which averaged 1.5% of the LPS. Concomitantly, the protein component (7 to 20%) was shown to contain the following amino acids: aspartic acid, threonine, serine glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine. Whole cells, as well as the LPS, of Phormidium possessed antigenic properties.     

Studies of lipopolysaccharides from Yersinia pseudotuberculosis subtypes VA and VB

Lipopolysaccharides (LPS) from various strains of Yersinia pseudotuberculosis type V have been isolated and characterised. Differences in sugar composition and serological activity of LPS from various strains within the same subtype of Y. pseudotuberculosis have been revealed.     

Structural studies on the immunodominant group of lipid A from lipopolysaccharide of Yersinia pseudotuberculosis.

Lipid A isolated from lipopolysaccharide of Yersinia pseudotuberculosis was used for immunization of rabbits to afford antisera to lipid A with titers of 1:640 in the passive hemolysis test. Exhaustion of immune serume with sheep erythrocytes decreased antibody titers up to 1:160. Authentic samples of 2-(DL-3-hydroxytetradecanoyl)amino-2-deoxy-D-glucose 6-phosphate, 2-tetradecanoylamino-2-deoxy-D-glucose 6-phosphate and 2-acetamido-2-deoxy-D-glucose 6-phosphate have been synthesized in order to carry out a comparative study of inhibitory activity of these compounds and lipid A using a system of lipid A and antiserum to lipid A. As a result, the immunodominant moiety of the lipid A of Y. pseudotuberculosis proved to contain a D-glucosamine residue acylated with 3-hydroxytetradecanoic acid at the amino group. The nature of the fatty acid acylating the amino group of glucosamine does not play an important role in the structure of immunodominant moiety of lipid A.     

Further structural studies of zosterine

Traces of either ferrous or ferric salts greatly increase the rate of the stepwise degradation of reducing sugars by alkaline hydrogen peroxide, as measured by formation of formic acid; addition of larger proportions of iron salts causes relatively smaller effects. The results showed that, unless unusually strict precautions are taken to exclude traces of iron, the free-radical cleavage of the hydroperoxide adducts of reducing sugars is far more rapid than the ionic cleavage. The catalytic effect of iron salts is counteracted by addition of magnesium salts. With d-glucose, inhibition of the catalytic effect of iron by magnesium depends on both the magnesium-iron ratio and the concentration at a given ratio. Measurements with various molar proportions of the salts indicated that a magnesium-iron complex, containing six atoms of magnesium to one of iron, is formed. Presumably, removal of iron by formation of this complex inhibits the free-radical degradation of hydroperoxide adducts. In marked contrast to the results obtained with reducing sugars, the degradation of potassium glyoxylate and of glyoxal by alkaline hydrogen peroxide is extremely rapid, and not catalyzed by iron or inhibited by magnesium. The results are in accord with an ionic, rather than a free-radical, cleavage of the hydroperoxide adducts of these compounds. The rapidity of the ionic reaction may be attributed to the ready availability of an electron pair from the adjoining carbon atom.     

Ancient DNA Analysis Affirms the Canid from Altai as a Primitive Dog

The origin of domestic dogs remains controversial, with genetic data indicating a separation between modern dogs and wolves in the Late Pleistocene. However, only a few dog-like fossils are found prior to the Last Glacial Maximum, and it is widely accepted that the dog domestication predates the beginning of agriculture about 10,000 years ago. In order to evaluate the genetic relationship of one of the oldest dogs, we have isolated ancient DNA from the recently described putative 33,000-year old Pleistocene dog from Altai and analysed 413 nucleotides of the mitochondrial control region. Our analyses reveal that the unique haplotype of the Altai dog is more closely related to modern dogs and prehistoric New World canids than it is to contemporary wolves. Further genetic analyses of ancient canids may reveal a more exact date and centre of domestication.     

Structure of Silenan, a Pectic Polysaccharide from Campion Silene vulgaris (Moench) Garcke

A pectic polysaccharide named silenan, [alpha]D20 +148.6 degrees (c 0.1; H2O), was isolated earlier from the aerial part of campion, Silene vulgaris (Moench) Garcke. Silenan has been shown to contain homogalacturonan segments as "smooth regions" and rhamnogalacturonan fragments as "hairy regions". The present study reveals a generalization of structural features of silenan. Silenan was subjected to enzymic digestion with pectinase, to Smith degradation, and to lithium-degradation to determine the conforming poly- and oligosaccharide fragments of "hairy regions" of silenan. The NMR-spectral data and mass-spectrometry confirmed that the core of the ramified region of silenan consisted of residues of alpha-rhamnopyranose 2-O-glycosylated with the residues of alpha-1,4-D-galactopyranosyl uronic acid. The part of the alpha-rhamnopyranose residues of the backbone are branched at O-4. On the basis of the data, the hairy regions of silenan proved to contain mainly linear chains of beta-1,3-, beta-1,4-, and beta-1,6-galactopyranan and alpha-1,5-arabinofuranan. The side chains of the ramified region were shown to have branching points represented 2,3-, 3,6-, 4,6-di-O-substituted beta-galactopyranose residues.     

Synthesis of sulfated pectins and their anticoagulant activity

The following pectins were sulfated: bergenan BC (the pectin of Bergenia crassifolia L), lemnan LM (the pectin of Lemna minor L), and galacturonan as a backbone of pectins. Pyridine monomethyl sulfate, pyridine sulfotrioxide, and chlorosulfonic acid were used as reagents for sulfation. Chlorosulfonic acid proved to be the optimal reagent for sulfation of galacturonan and other pectins. Galacturonan and pectin derivatives with different degrees of sulfation were synthesized and their anticoagulant activities were shown to depend on the quantity of sulfate groups in the pectin macromolecules.