Identification, isolation and physico-chemical properties of neurospecific alpha2-globulin]

In the immunization process of rabbits with the protein fraction of the water-salt extract from human brain partially and concentrated at 500-600 times was received antiserum revealed brain specific alpha 2-globulin that is not identical to the known cytoplasmatic brain specific antigens. This antigen has got electrophoretic mobility of alpha 2-globulins, molecular weight 90 +/- 10 kD and isoelectric point 4.1-5.4. Develop the procedure for purification of this antigen on the basis of the combination ion change, affinity, hydrophobic chromatography gel-filtration and isochromatofocusing.     

Revealing the role of predator-dependent disease transmission in the epidemiology of a wildlife infection: a model study

It is well known that predation/harvesting on a species subjected to an infectious disease can affect both the infection prevalence and the population dynamics. In this paper, I model predator?Cprey?Cpathogen interactions in the case where the presence of a predator indirectly affects the transmission rate of the infection in its prey. I call this phenomenon the predator-dependent disease transmission. Such a scenario can arise, for example, as a consequence of anti-predator defence behaviour, debilitating the immune system of the prey. Although being well documented, the predator-dependent disease transmission has rarely been taken into account in ecoepidemiological models. Mathematically, I consider a classical S-I-P ecoepidemiological model in which the infected and/or the healthy host can be consumed by a predator where the coefficient in the mass action transmission term is predator-dependent. Investigation of the model shows that including such a predator-dependent disease transmission can have important consequences for shaping predator?Cprey?Cpathogen interactions. In particular, this can enhance the survival of the predator, restricted in a system with a predator-independent disease transmission. I demonstrate the emergence of a disease-mediated strong Allee effect for the predator population. I also show that in the system with predator-dependent disease transmission, the predator can indirectly promote epidemics of highly virulent infectious diseases, which would die out in a predator-free system. Finally, I argue that taking into account predator-dependent disease transmission can have a destabilizing effect in a eutrophic environment, which can potentially cause the extinction of both species. I also show that including the predator-dependent disease transmission may increase the infection prevalence, and this fact will question the ??keeping herds healthy?? hypothesis concerning the management of wildlife infections by natural predators.     

Subcellular localization and self-interaction of plant-specific Nt-4/1 protein

The Nicotiana tabacum Nt-4/1 protein is a plant-specific protein of unknown function. Analysis of bacterially expressed Nt-4/1 protein in vitro revealed that the protein secondary structure is mostly alpha-helical and suggested that it could consist of three structural domains. Earlier studies of At-4/1, the Arabidopsis thaliana-encoded ortholog of Nt-4/1, demonstrated that GFP-fused At-4/1 was capable of polar localization in plant cells, association with plasmodesmata, and cell-to-cell transport. Together with the At-4/1 ability to interact with a plant virus movement protein, these data supported the hypothesis of the At-4/1 protein involvement in viral transport through plasmodesmata. Studies of the Nt-4/1-GFP fusion protein reported in this paper revealed that the protein was localized to cytoplasmic bodies, which were co-aligned with actin filaments and capable of actin-dependent intracellular movement. The Nt-4/1-GFP bodies, being non-membrane structures, were found in association with the plasma membrane, the tubular endoplasmic reticulum and endosome-like structures. Bimolecular fluorescence complementation experiments and inhibition of nuclear export showed that the Nt-4/1 protein was capable of nuclear-cytoplasmic transport. The nuclear export signal (NES) was identified in the Nt-4/1 protein by site-directed mutagenesis. The Nt-4/1 NES mutant was localized to the nucleoplasm forming spherical bodies. Immunogold labeling and electron microscopy of cytoplasmic Nt-4/1-containing bodies and nuclear structures containing the Nt-4/1 NES mutant revealed differences in their fine structure. In mammalian cells, Nt-4/1-GFP formed cytoplasmic spherical bodies similar to those found for the Nt-4/1 NES mutant in plant cell nuclei. Using dynamic laser light scattering and electron microscopy, the Nt-4/1 protein was found to form multimeric complexes in vitro.     

A new method for producing biologically active nanocomplexes by a noncovalent conjugation of proteins with viral particles

A new method for noncovalent immobilization of a peptide epitope on the virion surface was developed to simplify and standardize the procedures for producing viral nanocomplexes. The efficacy of this approach was demonstrated by the example of a model system comprising the tobacco mosaic virus, synthetic cationic polymer poly-N-ethyl-4-vinylpyridinium bromide, and a model polypeptide. The principle of sequential adsorption, underlying production of the triple system virion-polycation-protein, was used for electrostatic immobilization of a recombinant hydrophilic fragment of the influenza virus hemagglutinin (Flu1-3) on the virion surface. The method provided for a significant increase in the immunogenic activity of this potential artificial vaccine protein.