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Background. In terms of serological properties and immunization, the wild type of HBsAg HBV and its G145R mutant behave as different antigens. This testifies to serious structural changes, which presumably could have a significant impact on the morphogenesis of virions and subviral particles. Nevertheless, morphological and ultrastructural investigations of HBV with G145R mutation have not been carried yet. Objectives. Research of structural and morphological organization of HBV in the presence of the G145R escape mutation. Methods. Studies of sera, purified viruses and recombinant HBsAg were carried out by transmission electron microscopy by the method of negative staining and indirect reaction of immunelabeling using monoclonal antibodies of different specificity. Specimens of wild type HBV and HBV with S143L mutation obtained in an identical manner were used as the control. Results. The presence of typical virus particles of HBV was shown in the specimens of wild strain and HBV with S143L mutation. Specimens of HBV with G145R mutation were characterized by expressed morphological heterogeneity. In the initial serum and in the specimen of purified virus containing G145R mutant, large oval particles 60-70 nm and up to 200 nm in size, respectively, were found. The presence of antigen structures of HBV in all heterogeneous forms was confirmed. It was shown that forming of subviral particles in the process of expression of the recombinant HBsAg with G145R mutation depends on conditions of expression and purification of the protein. They can vary from well-formed circular and oval particles to practically unstructured fine-grained masses. Conclusion. Direct data on the impact of G145R escape-mutation in S-gene, in contrast to S143L mutation, on the morphogenesis of virions and subviral particles of HBV were obtained.

Abstract. The modern data about morphology as well as structural and functional organization of the parvovirus B19 genome, circulating virus genotypes are presented in the review. Special attention was paid to the clinical and epidemiological features of parvovirus infection (PVI). Authors focused on the distribution of PVI in different regions of Russia and on the own data concerning prevalence of this infection in the North-Western region of the country including data on pregnant women – main risk group for PVI. Methods of laboratory diagnostics of postnatal and congenital PVI have been described.

Introduction: Rotavirus infection is the leading cause of acute gastroenteritis among infants. The development of new vaccines against rotavirus A is urgent because the virus has many genotypes, some of which have regional prevalence. Virus-like particles (VLP) is a promising way to create effective and safe vaccine preparations.The purpose of the study is to develop the technology for the production of VLP, containing VP2, VP4, VP6 and VP7 of viral genotypes prevalent on the territory of the Russian Federation, and to give its molecular genetic and virological characteristics., Material and Methods: The virulent strain Wa G1P[8] of human RV A adapted to MARC-145 cell culture has been used. It was cultured and purified according to the method described by the authors earlier. Standard molecular genetic and cytological methods were used: gene synthesis; cloning into transfer plasmids; recombinant baculoviruses production in Bac-to-Bac expression system; VLP production in the insect cells; centrifugation in sucrose solution; enzyme-linked immunosorbent assay (ELISA); electron microscopy (EM); polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis., Results: VP4 and VP7 of the six most represented in Russia genotypes: G1, G2, G4, G9, P4, P8, as well as VP2 and VP6 were selected for VLP production. Recombinant baculoviruses were obtained with codon frequencies optimized for insect cells. Cabbage loopper (Trichoplusia ni) cell culture was coinfected with different combinations of baculoviruses, and VLP consisting of 2-4 proteins were produced. VLP were purified by centrifugation. The size and morphology of the particles matched the rotavirus A virion (by EM). The presence of rotavirus A proteins in VLP was confirmed by the ELISA, SDS-PAGE and western blot analysis., Conclusion: The technology for the synthesis of three-layer VLP consisting of VP2, VP4, VP6 and VP7 has been developed and optimized. The resulting VLP composition represents 6 serotypes of VP4 and VP7, which are most represented on the territory of Russia, and can be used for vaccine development.

Extracellular immunoreactive virus NP is accumulated in virus-containing fluid in the course of A/Duck/Ukraine/1/63(H3N8) influenza virus infection. The major part of this extracellular NP is included in viral RNP and characterized by relatively low molecular weight: 53 kD vs. 56 kD of virion NP. Extracellular immunoreactive NP is oligomerized. Presumably, there is partially intracellular cleavage of NP with loss of hydrophobic determinants. Such truncated NP in RNP is highly hydrophilic and passes through cell membranes. These data prompt the diagnosis of influenza infection by detection of free immunoreactive NP in analyzed fluids.

The first steps of the interaction of the temperate pilus-dependent phage 04 with susceptible and 04-lysogenic cells of Pseudomonas aeruginosa were investigated. The 04-lysogenic cells retained their ability to adsorb viral particles on the pili. However, after the translocation to the cell surface, the bacteriophage failed to infect the immune microorganism. It is assumed that was modified the surface of 04-immune cells due to lysogenic conversion, and this modification presented the terminal tail fibers of viral particles interacting from with the outer membrane of P. aeruginosa cells.

The synthesis of gag antigens of human immunodeficiency virus (HIV) by recombinant vaccinia virus strains containing the expressed genes gag and gag-pol and the capacity of these proteins to formation of virus-like particles during infection of various cell cultures were studied. The recombinant strain containing the truncated gag gene (p48gag) was shown to effectively synthesize gag polypeptides and to form immature virus-like particles during infection of all the cell cultures tested (CV-1, Hep-2, HT-29). The morphogenesis of mature virus-like particles was detected by electron microscopy only in infection of Hep-2 cells with a strain containing a complete gag-pol sequence of HIV.

Computer analysis of variola major virus (VAR) genomic fragment bounded by open reading frames (ORFs) D1R and A33L which is 47,961 bp long revealed 46 potential ORFs. The VAR proteins were compared with the analogous proteins of vaccinia virus strain Copenhagen. The subunits of DNA-dependent RNA polymerase, as well as the transcription factors, mRNA capping enzymes, and proteins necessary for the virion morphogenesis proved to be highly conservative within orthopoxviruses. The most pronounced differences between the VAR genome fragment under study and the corresponding vaccinia virus fragment were revealed in the vicinity of the gene encoding the A-type inclusion body protein. The possible functions of the analyzed viral proteins are discussed.

This is a critical review of the modern methods of gene mapping in the vaccinia virus genome. Experimental data are given on the localization of the vaccinia virus genes. Major attention is paid to the functions of the proteins encoded by the mapped genes.

Expression of urokinase in murine and rat cells was performed by two recombinant constructs, one containing cDNA and the other--hybrid (cDNA/genome) variant of human urokinase gene conserving 7 introns of 10, in the eukaryotic retrovirus vector pPS-3-neo. DNA of both constructs was introduced into packaging cell line psi 2 by a standard Ca-phosphate transfection technique. Infection of mouse and rat fibroblasts BALB/c 3T3 and Rat I with virus particles, produced by transfected psi 2 cells, led to an integration into the host genome of one or two recombinant proviral copies. Stable expression and secretion into the culture medium of glycosylated high molecular weight human urokinase was observed for both cell types. For the hybrid gene construct, precise excision of intervening sequences was shown during transferring of genetic material from packaging to recipient cells.

The I5 gene from the HindIII-I-fragment of the vaccinia virus strain L-IVP DNA was cloned into bacterial vector pUC19. The monospecific antiserum to the expression product of this gene in E. coli was obtained. This antiserum was demonstrated to co-precipitate the virion protein p90. The vaccinia virus strain L-LVP DNA was shown to have only one ORF coding the p90 protein instead of two ORF H5 and H4 as known for vaccinia virus strain WR. This protein is associated with the core of vaccinia virion, but some of its antigenic determinants are exposed on the surface of the viral particles.

Chicken embryonated eggs were coinfected with influenza A/FPV/Rostock and A/FPV/Weybridge strains. 25 plaque isolates were obtained from the mixed yield and their genetic content was analysed by polyacrylamide gel electrophoresis of H3-uridine-labelled vRNA in a modified gel system. At least 18 clones out of 25 plaque isolates proved to be reassortants; however, only one among them contained the homologous RNA-segments belonging to both parents. The results are in agreement with the concept of an ordered recruitment of vRNA-segments into virions.

Monkey kidney cells CV-1 were infected with recombinant vaccinia virus carrying HIV-1 gag gene with a deletion of 230 nucleotide pairs from the 3'-terminus. The main gene product detected in the lysates of infected cells was the gag precursor rp50. The protein was accumulated on the cell membranes suggesting that it had a myristylated N-terminus, and was cleaved by a recombinant virus specific protease with the formation of two proteins, p17 and p24 corresponding in molecular masses to mature gag proteins. Virus-like particles similar to immature HIV virions were budding from the surface of infected cells. They look like the ring of optically dense material covered with a lipid bilayer, of the same size (100-120 nm) and of the same density in a sucrose gradient (1.16-1.18 g/ml) as HIV-1 virions. The particles contained rp50 and cellular heterogeneous RNA. Thus, the unprocessed gag precursor with deleted 77 amino acid residues from the C-terminus is able to form virus-like particles in the absence of env proteins and virus-specific RNA, and these particles are budding from the cell surface. The question about the use of extracellular Gag-particles for AIDS diagnostic work and construction of vaccines is discussed.

Basic features of influenza virus genome structure, replication and evolution are reviewed with a special emphasis upon the segmentary structure of the genome and the use of cell mRNA as primer in virus-specific transcription. The structural and functional autonomy of virus genomic segments and the selection of the segments in the process of viral genome assembly is considered to be the basis for the gene reassortment and the appearance of recombinants. The reassortment of genes is discussed in relation to the nature of "new" antigenic subtypes of human influenza A virus, that is, to the orivin of antigenic shifts and pandemic strains. Another kind of antigenic variation (antigenic drift) is produced by the accumulation of mutations under the conditions of selection pressure in an immune population. Together with the conservation of earlier antigenic subtypes in animal populations these two types of evolutionary changes produce a complex pattern of influenza virus evolution. The prospects of influenza control are briefly discussed in connection with the characteristics of influenza virus genome structure and evolution.