Real-time oligonucleotide hybridization kinetics monitored by resonant mirror technique

The kinetics of hybridization of 11-meric and 14-meric oligonucleotides, dTGGGAAGAGGG (ODN-11) and dTGGGAAGAGG GTCA (ODN-14), with 14-meric oligonucleotide dpTGACCCTCT TCCCA (p14) attached to the surface of a cuvette was studied by the resonant mirror method. The treatment of the experimental curves with exponential equations leads to the following values for association (kas) and dissociation (kdis) rate constants at 25 degrees C: kas = 219 +/- 39 and 183 +/- 162 M-1 s-1, kdis = (2.0 +/- 0.4) x 10(-3) and (4 +/- 1) x 10(-4) s-1 for the duplexes (p14) x (ODN-11) and p14 x (ODN-14), respectively. The oligonucleotide dTGCCTTGAATGGGAA GAGGGTCA (ODN-23), which forms a hairpin structure, does not associate with p14. The data were compared with the results of melting curve detection and temperature-jump experiments. The association rate constants for ODN-11 and ODN-14 are much slower than those values in homogeneous aqueous solution. The dissociation rate constants have the same magnitude values as estimated by using association constants measured from melting curves but differ from the values estimated in temperature-jump experiments.     

Thermodynamics of interaction of phthalocyanine-oligonucleotide conjugates with single- and double-stranded DNA

Thermodynamics of interaction of phthalocyanine-oligonucleotide conjugates with single- and double-stranded DNA resulting in formation of duplexes and triplexes was measured by UV melting method. It was shown that a phthalocyanine moiety of conjugates stabilized the formation of duplexes and triplexes.     

Addition to the fauna of mosquitoes of the family Culicidae (Diptera) of the Novgorod region

Mosquitoes of 26 species of the family Culicidae were found in the Novgorod Province. During the researches in 1996-2001, five new species for the region were found: Aedes annulipes, Ae. impiger, Ae. riparius riparius, Ae. rossicus and Culex torrentium.     

Milk angiogenin (Review)

Recent data on angiogenin, a multifunctional member of pancreatic RNase protein superfamily, are summarized. Advances in the investigation of angiogenin structure, function, and properties are analyzed. Potentialities in natural angiogenin production from inexpensive dairy by-products are demonstrated.     

The expression of mutation sy2 causing nonhomologous synapsis in meiosis of diploid rye Secale cereale L

The cytological expression of spontaneous mutation sy2 isolated from a population of weedy rye was examined. It was demonstrated that the primary defect of meiosis in the mutant plants is nonhomologous synapsis, which occurs simultaneously with the homologous one. An electron microscope study of the synaptonemal complex (SC) at prophase I showed synaptic abnormalities that manifested as "switches" of synapting axial elements to the nonhomologous partner and the formation of foldbacks of lateral SC elements. The sy2 mutants are characterized by one to two such events per meiosis. Nonhomologous synapsis leads to the appearance of univalents at metaphase I (on average 4.16 +/- 0.022 per meiocyte) and multivalents (on average 0.12 +/- 0.007 per meiocyte). The presence of multivalents in 12.0% of meiocytes at metaphase I may result from recombination in ectopic regions of homology. It is suggested that the sy2 mutation impairs a component of the system that limits synapsis in meiocytes to only homologous chromosome pairs.     

Immunochemical characterization of Fraction I of Yersinia pestis strains by CAF1M gene

The role of caf1M gene in biogenesis of Yersinia pestis capsule was studied in natural strains of the agent with Fra+/- phenotypes and recombinant variants with ycaA (caf1+;caf1M;caf1A+;caf1R+) locus defect. These bacteria did not form a clearly discernible capsule stained by classical methods but synthesized Cafl, whose content in the cells was many times higher than in lysates, in external cell wall, and in the medium with reference Y. pestis EV NIIEG culture (caf1+;caf1M;caf1A+;caf1R+). However Caf1 was not detected on the surface or culture fluid of natural and mutant Y. pestis cells. Exclusive role of Caf1M in Caf1 delivery to Y. pestis cell surface, but not in F1 monomer folding, was proven. Retention of lipopolysaccharide (LPS), a typical SR-LPS configuration and epitope specificity of its components was demonstrated, ensuring similar reactivity in solid-phase enzyme immunoassay with a panel of monoclonal antibodies to Y. pestis LPS. Study of immunochemical properties of antigenic substances derived from caf1M-defective Y. pestis cells by isolation of F1 showed that these substances represent an envelope protein involved in the caf1+ strains (together with Caf1) in assembly of "mature" F1 molecule as a result of posttranslation modification of various genes products. Variants of identification of Y. pestis with Fra+ phenotype by means of monoclonal antibodies to F1, fibrinolysis/coagulase, or LPS in solid-phase enzyme immunoassay are discussed.     

Monoclonal antibodies for studying antigens of protein origin in serotyping of Yersinia pseudotuberculosis

Hybridomas producing monoclonal antibodies (MAb) to Yersinia pseudotuberculosis, serovars I-IV, responsible for serovar appurtenance, were obtained. Virtually all MAbs reacted with protein antigens in immunoblotting. The only exclusion was MAb 3A2 presumably reacting with a glycoprotein epitope of complex structure. Variability of Y. pseudotuberculosis antigenic structure, depending on culturing temperature, was confirmed. Polypeptides with mono- or polydetermined antigenic specificity were determined using MAbs.     

The effect of yeast glycans in experimental LPS-induced endotoxicosis

The immunomodulating action of yeast glycans obtained from Rhodotorula rubra (rhonasan) and Sporobolomyces albo-rubescens (heteroglycan Sp-50) was studied under the conditions of experimental endotoxicosis in mice, induced by the injection of the sublethal dose of Escherichia coli lipopolysaccharide (LPS). In endotoxicosis glycans produced a protective effect, depending on the time of injection. The study demonstrated that after the injection of glycans the survival rate of the animals increased and the LPS-inhibited function of peritoneal macrophages and B lymphocytes was completely or partially restored.