RESUMO
The protective properties of artificial mycobacterial particles versus BCG vaccine were studied in laboratory animals with experimental tuberculosis. The findings of the decreased rate of a tuberculous process and on the increased mean life span in animals inoculated with M. bovis suggest that immunization of guinea-pigs with mycobacterial particles promotes the enhanced development of antituberculous immunity in the animals. The paper proposes a promising method for designing artificial immunogens, the high-polymer antigenic structures that imitates mycobacterial particles.
Assuntos
Vacina BCG/imunologia , Mycobacterium bovis/imunologia , Vacinas contra a Tuberculose/imunologia , Tuberculose/prevenção & controle , Vacinas Sintéticas/imunologia , Animais , Interpretação Estatística de Dados , Modelos Animais de Doenças , Cobaias , Imunização , Técnicas Imunoenzimáticas , Fagocitose , Tuberculose/imunologiaRESUMO
Recent phylogenetic studies allowed the Mycobacterium tuberculosis complex to be divided into a number of the strain families. The W-Beijing family is one of most widespread M. tuberculosis variants frequently causing epidemic outbreaks. This family is genetically homogenous and conserved so that ETR A, B, C, D, E - typing is insufficient for the W-Beijing differentiation. All W-Beijing isolates have common profile (42435). This led to the false clustering in the molecular epidemiology study, especially in the region of predominance of the W-Beijing family. In this investigation we searched for the VNTR loci with high evolution rate, which were polymorphic in the W-Beijing genome. Eleven VNTR-loci were assayed in the DNA panel of 99 M. tuberculosis isolates from the tuberculosis patients in North-West and West-Siberian regions of Russia during the period from 2000 to 2001. Ninety nine strains of M. tuberculosis were divided into 74 VNTR-types, 51 isolates of the W-Beijing family were subdivided into 30 VNTR-types. The Hunter-Gudson index (HGDI) for all studied loci (ETR-A, ETR-C, ETR-E, V, V2, V3, V4, V5, V6, V10, V11) was close to one of the IS6110 RFLP indices being "the gold standard" of the M. tuberculosis complex genotyping. The V2, V3 loci located in the sequences of the PPE gene family, were highly polymorphic and more discriminative then others (HGDI is about 0.8). The congruence between the IS6110 RFLP-typing and 11 loci VNTR-typing was measured during genotyping for 23 isolates of the W-Beijing family. The isolates were divided into 9 genotypes by the IS6110 RFLP and into 13 variants by the VNTR-typing. The profiles correlation coefficient was 0.767689 that reflected the differences in the rate and type of the given genome target evolution.
Assuntos
Repetições Minissatélites/genética , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/genética , Polimorfismo de Fragmento de Restrição , Tuberculose/microbiologia , Técnicas de Tipagem Bacteriana , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Federação RussaRESUMO
Phage display peptide library f88-4/15 (G. P. Smith, USA) was used for mapping the hemagglutination activity domain of glycoprotein E2 of alphaviruses. Using affinity selection and ELISA, we selected the clones binding monoclonal antibody 4H5 to Venezuelan equine encephalomyelitis virus and inhibiting alphavirus hemagglutinating activity. Analysis of the similarity between the peptides amino acid sequences with the alphavirus glycoprotein E2 sequences revealed a structural motive of 4 amino acid residues (HTSR) which was identified in the 85-88 region. Bacteriophages F36 and F19 contained motives corresponding to 102-SXXM-105 and 109-AXXP-112 regions in alphavirus proteins E2. These data permit us to propose that the detected regions are fragments of a group-specific alphavirus hemagglutination domain.
Assuntos
Colífagos/genética , Vírus da Encefalite Equina Venezuelana/genética , Hemaglutininas Virais/genética , Biblioteca de Peptídeos , Proteínas do Envelope Viral/genética , Sequência de Aminoácidos , Ensaio de Imunoadsorção Enzimática , Escherichia coli/virologia , Dados de Sequência Molecular , Proteínas do Envelope Viral/químicaRESUMO
Four genetic constructions have been designed, capable of producing in E. coli the hybrid beta-galactosidases containing the encephalitogenic determinant 114-122 of myelin basic protein. The ability of chromatography-purified proteins to cause allergic encephalomyelitis in guinea pigs has been investigated. Only one out of four proteins carrying at least one complete replica of encephalitogenic determinant did induce allergic encephalomyelitis in animals. Effects of the structural context of the encephalitogenic determinant on its functional activity are discussed.
Assuntos
Encefalite/etiologia , Hipersensibilidade/complicações , Proteína Básica da Mielina/metabolismo , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Animais , Cromatografia de Afinidade , Escherichia coli/enzimologia , Cobaias , Dados de Sequência Molecular , Proteína Básica da Mielina/genética , Proteína Básica da Mielina/isolamento & purificação , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/isolamento & purificação , Plasmídeos , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , beta-Galactosidase/genéticaRESUMO
Mutagenic properties of oligonucleotides with pyrophosphate internucleotide bond was studied. It was shown that the pyrophosphate bond in the oligo structure does not induce mutations but promotes a more efficient induction of marker deletions predetermined by the nucleotide sequence as compared to the native oligonucleotide. Marker deletion induction proceeds according to the repair mechanism as homozygotes dominate in the mutant generation.
Assuntos
Bacteriófagos/genética , Difosfatos/toxicidade , Mutagênese Sítio-Dirigida , Mutagênicos , Oligonucleotídeos/toxicidade , Sequência de Aminoácidos , Sequência de Bases , DNA Viral/efeitos dos fármacos , DNA Viral/genética , Eletroforese em Gel de Poliacrilamida , Genes Virais , Dados de Sequência Molecular , Oligonucleotídeos/genéticaRESUMO
The mutagenic properties of phosphotriester analogues revealed in course of interaction with linearized plasmid DNA were studied. The plasmid-based model system permitting one to test reliably the induced mutations is proposed. The efficiency of mutagenesis was shown to depend on the length of the oligonucleotide-mutagen and the genotype of the transformed Escherichia coli strain. The possible mechanisms involved in mutagenesis are discussed.
Assuntos
DNA Bacteriano/genética , DNA Viral/genética , Ésteres/química , Mutagênese Sítio-Dirigida , Oligonucleotídeos/química , Compostos Organofosforados/química , Bacteriófagos/genética , Sequência de Bases , Escherichia coli/genética , Genes Bacterianos , Genes Virais , Dados de Sequência MolecularRESUMO
The mutation system has been developed to study the mutagenic properties of modified oligonucleotide analogs. The mutagenic properties of oligonucleotides containing one ribonucleotide have been examined. The presence of a ribonucleotide is shown not to induce any mutations. But when the oligonucleotide induces two marker deletions detached by 6 nucleotides they may be repaired separately, in this case the deletion bordering with the ribonucleotide is predominantly repaired.
Assuntos
Reparo do DNA , Replicação do DNA , Mutagênese Sítio-Dirigida , Oligonucleotídeos/genética , Ribonucleotídeos/genética , Sequência de Bases , Dados de Sequência MolecularRESUMO
The mutation system has been suggested in an effort to test insertion and deletion mutants by changing the Lac-phenotype of bacterial colonies transformed by mutant DNA. This system also makes possible to determine heterozygotes and homozygotes among the mutants. The yield of mutants in shown to depend on the structure of the DNA heteroduplex region. The yield of deletion mutants is greater than that of insertion mutants. Heterozygotes prevail in mutant colonies (greater than 90%).