Correlation of genetic variability with safety of mumps vaccine Urabe AM9 strain

The Urabe AM9 strain of mumps vaccine live is known for its genetic instability and some vaccines derived from this strain were withdrawn from the market due to an excessive number of vaccine-associated parotitis and meningitis cases. To identify the molecular basis of this instability, we determined complete nucleotide sequences of several stocks of the Urabe strain used for vaccine production by different manufacturers and of two clinical isolates from cases of vaccine-associated meningitis. In contrast to previously published studies relating the Lys335 --> Glu mutation in the viral HN gene with neurovirulence of mumps virus, we could not confirm any association of this mutation with the safety of mumps vaccine. Each of the three vaccine stocks studied had its own characteristic profile of mutations that was identified by cDNA sequencing and quantitated by mutant analysis by PCR and restriction enzyme cleavage. Determination of the mutational profile of mumps vaccine lots could allow vaccine manufacturers to characterize seed viruses and monitor the consistency of vaccine production to prevent emergence of virulent revertants.     

Detection and genotyping of human group A rotaviruses by oligonucleotide microarray hybridization

A rapid and reliable method for the identification of five clinically relevant G genotypes (G1 to G4 and G9) of human rotaviruses based on oligonucleotide microarray hybridization has been developed. The genotype-specific oligonucleotides immobilized on the surface of glass slides were selected to bind to the multiple target regions within the VP7 gene that are highly conserved among individual rotavirus genotypes. Rotavirus cDNA was amplified in a PCR with primers common to all group A rotaviruses. A second round of nested PCR amplification was performed in the presence of indodicarbocyanine-dCTP and another pair of degenerate primers also broadly specific for all genotypes. The use of one primer containing 5'-biotin allowed us to prepare fluorescently labeled single-stranded hybridization probe by binding of another strand to magnetic beads. The identification of rotavirus genotype was based on hybridization with several individual genotype-specific oligonucleotides. This approach combines the high sensitivity of PCR with the selectivity of DNA-DNA hybridization. The specificity of oligonucleotide microchip hybridization was evaluated by testing 20 coded rotavirus isolates from different geographic areas for which genotypes were previously determined by conventional methods. Analysis of the coded specimens showed that this microarray-based method is capable of unambiguous identification of all rotavirus strains. Because of the presence of random mutations, each individual virus isolate produced a unique hybridization pattern capable of distinguishing different isolates of the same genotype and, therefore, subgenotype differentiation. This strain information indicates one of several advantages that microarray technology has over conventional PCR techniques.     

Differences in oligomerization of nucleocapsid protein of epidemic human influenza A(H1N1), A(H1N2) and B viruses

A comparative analysis of involving the nucleocapsid protein (NP) into shaping-up of SDS-resistant oligomers was carried out presently in circulating epidemic strains of human influenza, viruses A and B. The study results of viral isolates obtained from clinical samples and recent standard strains revealed that the involvement of NP in the SDS-resistant oligomers, which are different in various subtypes of influenza A viruses. According to this sign, the human viruses A(9H3N2) are close to the avian ones, in which, as proved by us previously, virtually the entire NP transforms itself into the oligomers resistant to SDS. About 10-20% of NP are involved in shaping-up the virus influenza A(H1N1) of SDS-resistant oligomers. No SDS-resistant NP-oligomers were detected in influenza of type B. It is suggested that the prevalence of human viruses A(H3N2) in NP-oligomers are the peculiarities of NP structure and of the presence of the PB1 protein from avian influenza virus.     

Dependence of oligomerization of influenza virus nucleoprotein on the species affiliation of the virus

Comparison of human and avian influenza virus nucleoprotein (NP) oligomerization showed that the efficiency of NP oligomerization is different in influenza viruses of different origin. NP oligomerization is virtually complete in avian influenza viruses, while in human influenza viruses only part of monomeric NP is oligomerized. The authors discuss the utilization of NP oligomerization efficiency as a sign for identification of the origin of influenza virus.     

Genomic analysis of vaccine-derived poliovirus strains in stool specimens by combination of full-length PCR and oligonucleotide microarray hybridization

Sabin strains of poliovirus used in the manufacture of oral poliovirus vaccine (OPV) are prone to genetic variations that occur during growth in cell cultures and the organisms of vaccine recipients. Such derivative viruses often have increased neurovirulence and transmissibility, and in some cases they can reestablish chains of transmission in human populations. Monitoring for vaccine-derived polioviruses is an important part of the worldwide campaign to eradicate poliomyelitis. Analysis of vaccine-derived polioviruses requires, as a first step, their isolation in cell cultures, which takes significant time and may yield viral stocks that are not fully representative of the strains present in the original sample. Here we demonstrate that full-length viral cDNA can be PCR amplified directly from stool samples and immediately subjected to genomic analysis by oligonucleotide microarray hybridization and nucleotide sequencing. Most fecal samples from healthy children who received OPV were found to contain variants of Sabin vaccine viruses. Sequence changes in the 5' untranslated region were common, as were changes in the VP1-coding region, including changes in a major antigenic site. Analysis of stool samples taken from cases of acute flaccid paralysis revealed the presence of mixtures of recombinant polioviruses, in addition to the emergence of new sequence variants. Avoiding the need for cell culture isolation dramatically shortened the time needed for identification and analysis of vaccine-derived polioviruses and could be useful for preliminary screening of clinical samples. The amplified full-length viral cDNA can be archived and used to recover live virus for further virological studies.     

The status and outlook of the training of pathologists in the RSFSR

Pathology service in the RSFSR suffers, at present, from the lack of pathologists: only 2393 (57.3%) of 4174 positions are occupied. Particularly difficult is the situation in Eastern Siberia and Moscow where only 47.7 and 48.6% positions, respectively, are covered. Lack of professional pathologists is aggravated by an artificial decrease of positions number as compared to real need, by the increase of proportion of persons retired or those having a preretirement age (30%), by a high percentage (over 30% of positions) of persons experiencing pathology as a second profession (65% of them do not have a sufficient knowledge and practice in pathology), by a low level of medical education in general and nonsufficient promotion of pathologists (only 39.3% pathologists have attestation categories). To solve the crisis the RSFSR Ministry of Health started in 1988/89 4-year training of pathologists at the pathology chairs of the RSFSR Medical Institutes: subinternship (1 year), internship (1 year), clinical internship (2 years). The realization of this program will result in turning out of 724 pathologists by 1994. The progress in pathologists training will require the improvement of technical basis of pathology chairs and departments and solution of certain organizational problems.     

Microbial fuel cells as an alternative power supply

Purpose of the work was designing and prototyping of microbial fuel cells (MFC) and comparative evaluation of the electrogenic activity of wastewater autochthonous microorganisms as well as bacterial monocultures. Objects were model electrogenic strain Shewanella oneidensis MR-1, and an Ochrobactrum sp. strain isolated from the active anode biofilm of MFC composed as an electricity generating system. The study employed the methods typically used for aerobic and anaerobic strains, current measurement, identification of new electrogenic strains in microbial association of wastewater sludge and species definition by rRNA 16-S. As a result, two MFCs prototypes were tried out. Besides, it was shown that electrogenic activity of S. oneidensis MR-1 and Ochrobactrum sp. monocultures is similar but differs from that of the microbial association of the anode biofilm.     

Native and renatured oligomer-dependent epitopes of intracellular influenza virus nucleocapsid protein

Intracellular NP oligomers have been shown to react with some anti-NP monoclonal antibodies (mAbs) in radio-immnoprecipitation, immunoblotting, and dot immunoassay. Soluble NP monomers obtained after thermal dissociation of NP oligomers are not recognized by mAbs unlike the NP monomers whose concentration increased by about 100-fold due to transfer to the nitrocellulose membrane after polyacrylamide gel electrophoresis. The findings demonstrated that in the intact NP oligomers there were epitopes determined by their quaternary structure. These oligomer-dependent epitopes may be renaturated in vitro under the conditions allowing for a concentration-dependent NP-NP association.     

Microarray-based assay for the detection of genetic variations of structural genes of West Nile virus

Adaptation through fixation of spontaneous mutations in the viral genome is considered to be one of the important factors that enable recurrent West Nile virus (WNV) outbreaks in the U.S. Genetic variations can alter viral phenotype and virulence, and degrade the performance of diagnostic and screening assays, vaccines, and potential therapeutic agents. A microarray assay was developed and optimized for the simultaneous detection of any nucleotide mutations in the entire structural region of WNV in order to facilitate public health surveillance of genetic variation of WNV. The DNA microarray consists of 263 oligonucleotide probes overlapping at half of their lengths which have been immobilized on an amine-binding glass slide. The assay was validated using 23 WNV isolates from the 2002-2005 U.S. epidemics. Oligonucleotide-based WNV arrays detected unambiguously all mutations in the structural region of each one of the isolates identified previously by sequencing analysis, serving as a rapid and effective approach for the identification of mutations in the WNV genome.