Xylogalacturonan-enriched pectin from the fruit pulp of Adansonia digitata: Structural characterization and antidepressant-like effect.

The low methyl-esterified and acetylated xylogalacturonan (DM 20 %, DA 2 %, Mw ∼ 58 kDa) was isolated by water extraction for 4 h × 2 at 50 °C (yield 23 %) from the pulp of baobab fruit (Adansonia digitata L.). Subsequent tightening of the conditions for water extraction by mean increasing the temperature to 70 °C and time to 12 h led to the co-extraction of small amounts of starch components and RG I with xylogalacturonan. Structural analysis (DEAE-cellulose ion-exchange chromatography, HPSEC, monosaccharide analysis, NMR spectroscopy) revealed that about 12 mol. % of 1,4-linked α-GalpA residues were substituted by single ß-Xylp residues at the O-3 position. The xylogalacturonan was found to possess an antidepressant-like effect in mice. The study offers using the baobab fruit as a rich source of soluble dietary fiber - water-soluble pectin with beneficial physiological effect.

Determination of the parameters of binding between lipopolysaccharide and chitosan and its N-acetylated derivative using a gravimetric piezoquartz biosensor.

The interaction of endotoxin (lipopolysaccharide - LPS) with low molecular weight chitosan (5.5 kDa), its N-acylated derivative and chitoliposomes was studied using a gravimetric piezoelectric quartz crystal microbalance biosensor. The optimal conditions for the formation of a biolayer based on immobilized LPS on the resonator surface and its regeneration were elaborated. The association and dissociation rate constants for LPS binding to chitosans were determined and the affinity constants (Kaf) were calculated based on the data on changes in the oscillation frequency of the quartz crystal resonator. The Kaf values correlated with the ones obtained using other methods. The affinity of N-acylated chitosan binding to LPS was higher than that of the parent chitosan binding to LPS. Based on the results obtained, we suggest that water-soluble N-acylated derivatives of chitosan with low degree of substitution of amino groups could be useful compounds for endotoxin binding and neutralization.

[Piezoquartz immunosensors for assessing the interactions between Yersinia enterocolitica lipopolysaccharides and antibodies to them].

The utility of a piezoquartz immunosensor coated with lipopolysaccharides (LPS) for the quantification of antibody specificities was demonstrated. Immunochemical reactions were monitored according to the changes in the weight of sensor bioreceptor layer with high sensitivity (detection limit, 1.3 microg/ml) and assay rate (10 min) without any additional labels. The capabilities of this sensor were demonstrated by the example of quantifying the cross-reactivity of blood serum antibodies with the LPS of Yersinia enterocolitica serotypes O:3, O:5, O:5.27, O:6.30, and O:6.31. The proposed approach is promising for clinical diagnostics of yersiniosis, an infectious intestinal disease.

[Detection of sulfamethoxazole by a piezoquarz immunosensor]. / Opredelenie sul'fametoksazola s pomoshch'iu p'ezokvartsevogo immunosensora.

A mass susceptible immunosensor for FIA of sulfamethoxazole residues in liquid products was designed. The immunosensor is based on piezoelectric transducer. Hapten-protein conjugate (SMX-Diazo-BSA) immobilized on the preliminarily silanized electrode surface of piezoelectric quartz crystal was used as the bioreceptor coating. Optimization of the FIA conditions permitted to develop a simple and express procedure for one-step detection of sulfamethoxazole in a sample and further regeneration of the bioreceptor layer. The measuring ranges are 1 to 50 ng/ml and the detection limit is 0.15 ng/ml. The detection results were compared with the HPLC data. The advantages of the new procedure are its simplicity and rapid provision of the analysis results, possible direct detection of the analyte without additional label and repeated use of the bioreceptor layer. The new immunosensor was applied to testing of various milk specimens. It was shown that the quantity of sulfamethoxazole in all the specimens was lower than the recommended Euroresidue standards (100 ng/ml).

Structural studies of O-specific polysaccharide chains of the lipopolysaccharide from Yersinia enterocolitica serovar O:10.

Lipopolysaccharide (LPS) was isolated from Yersinia enterocolitica serovars O:10 and O:10 KL and the structural pattern of O-specific sugar chains elucidated. The rhamnan and L-xylulose (L-threo-pent-2-ulose) as constituents of the O-specific polysaccharide were obtained by autohydrolysis of the LPS. The rhamnan was shown to be a linear, alpha-(1-->3)-linked polysaccharide in the D configuration. L-Xylulose was purified using paper chromatography on a preparative scale and its structure was confirmed by 13C NMR spectroscopy. Using sugar and methylation analysis and 13C NMR spectroscopy of the LPS and the rhamnan, the structural features of the disaccharide repeating unit of the Y. enterocolitica O:10 O-specific polysaccharide were elucidated as: [formula: see text]

[Immunochemical study of the lipopolysaccharides of Yersinia enterocolitica serovars O5 and O5.27]. / Immunokhimicheskoe izuchenie lipopolisakharidov Yersinia enterocolitica serovarov O5 i O5,27.

Y. enterocolitica lipopolysaccharides (LPS), serovars O5 and O5.27, have similar antigenic specificity. The LPS of serovar O5.27 has been shown to contain no factor O27. Residual alpha-L-rhamnose, glycosylated by D-xylulose, has been found to play an important role in the formation of factor O5, common for both serovars.

[The structure of O-specific polysaccharide from Yersinia enterocolitica serotype O:6.31 lipopolysaccharide]. / Struktura O-spetsificheskogo polisakharida iz lipopolisakharida Yersinia enterocolitica serovara O:6.31.

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)

Structural studies on O-specific polysaccharides of lipopolysaccharides from Yersinia enterocolitica serovars O:1,2a,3, O:2a,2b,3 and O:3.

Lipopolysaccharides from Yersinia enterocolitica serovars O:1,2a,3, O:2a,2b,3 and O:3 have been isolated and characterized. 6-Deoxy-L-altrose residues were shown to be the main constituents of lipopolysaccharides isolated in addition to residues of L-rhamnose, D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-glycero-D-manno-heptose and L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid being minor components of sugar chains. Mild hydrolysis of lipopolysaccharides with acetic acid furnished O-specific polysaccharides, which are composed of 6-deoxy-L-altrose. Using 13C-NMR spectroscopy and methylation data, the structural features of backbones have been elucidated as follows: ----2)-6d-L-Altp(beta 1----2)-6d-L-Altp(beta 1----3)-6d-L-Altp)(beta 1----for serovars O:1,2a,3 and O:2a,2b,3;----2)-6d-L-Altp(beta 1----for serovar O:3. In addition, O-polysaccharide of serovar O:2a,2b,3 was found to contain an O-acetyl group at the C-3 position of some 1,2-linked sugar residues.

Studies of lipopolysaccharides from Yersinia pseudotuberculosis subtypes VA and VB.

Lipopolysaccharides (LPS) from varions 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.