Sergei Yu. Shchyogolev

Use of a synthetic foot-and-mouth disease virus peptide conjugated to gold nanoparticles for enhancing immunological response

Foot-and-mouth disease is an acute, highly contagious infection of domestic and wild cloven-hoofed animals, which can be transmitted to humans. In many cases, the existing vaccines are not quite effective. The purpose of this study was to test the possibility of using gold nanoparticles as an antigen carrier and an adjuvant. The immunogenic properties of gold nanoparticles were assessed by conjugating the particles to a synthetic peptide of the VP1 capsid protein of the foot-and-mouth disease virus. The resulting conjugate (with or without the use of complete Freund’s adjuvant), a commercial vaccine, and the native peptide served to immunize guinea pigs. The titer and sensitivity of the raised antibodies were maximal for the combination comprising the nanoparticle–peptide conjugate and complete Freund’s adjuvant. Antibody biosynthesis was accompanied by increased production of proinflammatory cytokines (especially IFN-γ) and by stimulation of the respiratory activity of peritoneal macrophages. The use of gold nanoparticles as a hapten carrier enhanced the immune response even when complete Freund’s adjuvant was not used.

Effect of gold nanoparticles on the respiratory activity of peritoneal macrophages

This work was undertaken to investigate the effect of antigen-conjugated gold nanoparticles on the functional activity of cells of the reticuloendothelial system. Experiments using rat and mouse peritoneal cells assessed the dynamics of the total respiratory activity of macrophages and the activity of mitochondrial dehydrogenases on exposure to colloidal gold conjugates of high- and lowmolecular-weight antigens. Both gold nanoparticles and their antigen conjugates stimulated the respiratory activity of the macrophages and the activity of macrophage mitochondrial enzymes. This stimulation may be an essential factor determining the adjuvant properties of colloidal gold, found by us in prior work.

Identification of an O-linked repetitive glycan chain of the polar flagellum flagellin of Azospirillum brasilense Sp7.

This is the first report to have identified an O-linked repetitive glycan in bacterial flagellin, a structural protein of the flagellum. Studies by sugar analysis, Smith degradation, (1)H and (13)C NMR spectroscopy, and mass spectrometry showed that the glycan chains of the polar flagellum flagellin of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 are represented by a polysaccharide with a molecular mass of 7.7 kDa, which has a branched tetrasaccharide repeating unit of the following structure:

Spectroturbidimitry as applied to biomedical and immunological investigations

Methods of optical shifting spectroscopy and laser nephelometry may be used to register antigen-antibody reaction. Usage of laser nephelometry in serodiagnostics, characteristics of a specific step in humoral immune reaction in infections, postinfectious and postinoculation processes response and immunity tension in some infectious diseases were investigated.

Anisotropic and spectral properties of biological scattering objects with the ordered particle orientation

Particle orientation in a disperse medium results both in anisotropic properties and in the changes in spectral transmittancy. To determine theoretically the effects of such kind a general approach based on the joint use of both the equation of Brownian rotation diffusion and the Mueller matrix for a thin slab of anisotropic medium has been developed. The optical properties of scatterers are described in terms of the first and second Born approximation and the exact T-matrix method. The goal of the investigations is to develop adequate optical models for interpretation of the experimental data obtained for the ordered disperse systems. In this paper, anisotropic properties of oriented disperse systems are discussed in a review manner, while the orientational turbidimetric effect is considered in detail.

Optical activity of the anisotropic solutions of cellulose acetates in mesophasogenic solvents

The optical activity of the cholesteric liquid crystalline phases of solutions of cellulose diacetate in nitromethane and dimethylsulfoxide was studied. These systems exhibited optical activity anisotropy (i.e. the value of the specific optical rotation [α] varied with the orientation of the specimen). The contributions of the isotropic component and the anisotropic components of [α] were identified. The harmonic decomposition of the anisotropic component identified the separate contributions from the primary and secondary structures of the polymer and from the supramolecular twisted helicoidal structure of the cholesteric phase.

Use of the Dot-Blot Immunogold Assay to Identify a Proliferative Antigen in the Initial Cells of a Wheat Stem Meristem

Abstract We have devised a protocol for the isolation and identification of a proliferative antigen of the initial cells of wheat stem meristems (termed PAI). We have carried out a variety of immunochemical and immunocytochemical methods, using colloidal gold (CG) complexed with monospecific antibodies to PAI as the marker for the detection of PAI. We have been able to determine the effectiveness of immunoaffinity chromatography in isolating PAI from plant tissues and have shown the advantages of CG over enzyme labels for identification of the antigen. Finally, we have obtained a purified preparation of PAI and have determined its molecular mass (∼83 kDa).

Immunological Properties of Azospirillum Cell Surface: the Structure of Carbohydrate Antigens and Evaluation of their Involvement in Bacteria-Plant Contact Interactions

Immunization of rabbits with glutar aldehyde-treated intact Azospirillum cells results in the production of antibodies specific mainly with regard to the cell O-antigens. EPS, CPS, and O-specific polysaccharides of A. brasilense Sp 7 are antigenically identical. Pre-treatment of the wheat seedling roots and a carrot cell suspension with LPS of strain Sp 245 promotes significantly bacterial adhesion to wheat roots and Azospirillum-induced agglutination of carrot cells. It also leads to an increased synthesis of the major proteins in the wheat root apoplast, which is comparable with the plant response to inoculation with whole cells. This may be explained by an active effect of Azospirillum LPS on the receptor systems of plant cells.

Inverse problems in spectroturbidimetry of biological disperse systems with random and ordered particle orientation

Several approaches to increasing the number of parameters of suspended particles that can be determined by a spectroturbidimetric method have been analyzed. It has been shown that, in principle, this problem can be solved invoking spectral characteristics obtained under conditions of complete or partial particle orientation in the stationary and relaxation regimes. Informative potentialities of combining the methods of electro-optics and spectroturbidimetry have been considered. It has been found that eventually for a given disperse system in situ, it is possible to obtain the following set of parameters: particle mean size, shape characteristic and refractive index, number and mass-volume concentration of particles, their total surface area per unit volume of the suspension and the effective value of particle surface polarizability.

Effect of bacterial lipopolysaccharides on morphogenetic activity in wheat somatic calluses

We evaluated the effect of lipopolysaccharides from the plant-growth-promoting associative bacterium Azospirillum brasilense Sp245 and from the enteric bacterium Escherichia coli K12 on the morphogenic potential of in vitro-growing somatic calluses of soft spring wheat (Triticum aestivum L. cv. Saratovskaya 29). A genetic model was used that included two near-isogenic lines of T. aestivum L. cv. Saratovskaya 29 with different embryogenic capacities; one of these lines carries the Rht-B1 dwarfing gene, whereas the other lacks it. When added to the nutrient medium, the lipopolysaccharide of A. brasilense Sp245 promoted the formation of calluses with meristematic centers and stimulated the regeneration ability of the cultured tissues in both lines. By contrast, the lipopolysaccharide of the enteric bacterium E. coli K12 barely affected the morphogenetic activity of callus cells and the yield of morphogenic calluses and regenerated plants. These findings indicate that the lipopolysaccharide of the plant-growth-promoting associative bacterium A. brasilense Sp245 specifically enhances the morphogenetic activity of wheat somatic tissues, which increases the efficacy of culturing of genotypes with a relatively low morphogenic potential. The results of the study may contribute to the improvement of the efficacy of plant cell selection and gene engineering and to a better understanding of the mechanisms responsible for plant recognition of lipopolysaccharides of associative bacteria.