[Experimental evaluation of the biological risks of introduction of the genetically modified microorganism (GMM) B. subtilis VKPM B-7092 into the environment].

Experimental evaluation of the biological risks of introducing the genetically modified microorganism (GMM) B. subtilis VKPM B-7092, an active ingredient of the probiotic VETOM 1.1, into an open system was performed.

[Experimental evaluation of the protective properties of some nonwoven materials for respiratory protection means and prospects of their use].

The protective properties of nonwoven materials (Spandbond, SMS) used to manufacture 3-5-layer medical masks, by using model physical and bacterial test aerosols, were experimentally assessed. It was shown that the more layers of the materials, the less permeable they became for test aerosols. Three-five-layer masks made from SMS at a density of 42 g/m2 were found to have higher protective properties for oil mist and fine aerosol than those made from Spandbond at a density of 25 g/m2.

[Oligomerization of DNA-(adenine-N6)-methyltransferase from phage T4 and its effect on the catalytic characteristics of the enzyme].

The structural and catalytic properties of the phage T4 DNA-(adenine-N6)-methyltransferase (EC 2.1.1.

[Sequence specific conjugates of minor groove ligands with inosine containing oligodeoxyribonucleotides].

Conjugates of the distamycin tetrapyrrole analogue containing four pyrrolecaboxamide fragments (MGB) with inosine-containing oligodeoxyribonucleotides were synthesized. The stability of duplexes formed by these conjugates depends on the composition of inosine-containing pairs and decreases in the order: IC > IA > > IT. For the duplexes (d(TTTATATA)p(MGB))2, (d(TTCICICI)p(MGB))2, and (d(TTAIAIAI)p(MGB))2, the melting temperatures are 68, 54, and 35-45 degrees C, respectively; (d(TTTITITI)p(MGB))2 forms no duplexes at temperatures above 4 degrees C.

[Diastereomers of nonionic oligonucleotide analogs. VI. Isolation of diastereomers of ethyl phosphotriesters of the octanucleotide d(GCCAAACA) by high performance affinity chromatography].

Diastereomers of oligonucleotide ethyl phosphotriesters were separated by high-performance complementary (affinity) chromatography on a column with the immobilized complementary oligonucleotide. The elution buffer contained 0.18 M K2HPO4, pH 7.

[The primary structure of the hemagglutinin gene of strain A/Riga/9977/86--a drift variant of influenza virus A(H3N2)].

The hemagglutinin gene primary structure of influenza virus A/Riga/9977/86 (H3N2) belonging to the "Coen/84" antigenic subgroup was determined by primer sequencing. A comparative analysis confirmed that the reversions of amino acids in the late stages of the H3 influenza virus subtype antigenic drift became more frequent and the antigenic variants remained in epidemic circulation longer. The possible role of some mutations is discussed.

[A study of substrate specificity of DNA-methylases from Flavobacterium okeanokoites].

The specificity of DNA methylase M. FokI towards oligonucleotides containing sequence 5'..

[Effect of the structure of oligonucleotide substrates on interaction with methylase Eco dam].

The interaction of Eco dam methylase with various synthetic oligonucleotide substrates was investigated. The "imperfect" duplexes contained a normal GATC recognition sequence in one chain of the enzyme recognition site and had some defects in the complementary chain, i.e.

[Effect of the structure of oligonucleotide substrates on kinetic parameters of interaction with BamHI restrictase].

Kinetic values of the BamHI endonuclease interaction with synthetic oligonucleotides, containing some defects, have been determined. These defects were: the absence of the one internucleotide phosphate in the GGATCC sequence; substitution of a phosphate linkage by a methylphosphonate one; 5'-protruding end of the double-stranded oligonucleotide substrate. Some modifications resulted in the increase of the initial rates of cleavage due to higher Vmax values for these substrates.

[Chemical synthesis and properties of oligonucleotide substrates for restriction endonuclease BamHI and methyltransferase Eco dam].

Oligodeoxyribonucleotides which form a number of duplexes, containing the recognition sequences for endonuclease BamHI and DNA methylase Eco dam, were synthesised by the phosphotriester approach. Furthermore, synthesis of 3'-phosphorylated oligodeoxyribonucleotides from corresponding S-methyl phosphorothioate triester oligomers is described. The synthetic duplexes are characterized by some defects in the recognition sequences for endonuclease BamHI and methylase Eco dam, viz.

[Cleavage of synthetic RNA-DNA hybrids with restriction endonucleases BamH1 and Sau3A].

Synthetic oligodeoxyribonucleotides, containing one or two ribonucleotides in the recognition sequence, and RNA--DNA hybrids were tested for their activity in cleavage with BamH1 and Sau3A endonucleases. The replacement of dG with G in the first position of BamH1-site (GGATCC) of one of the chains does not affect the rate of the BamH1 hydrolysis. The similar heteroduplex, containing G residue in the second position, displays a decreased rate of the BamH1 hydrolysis of the modified strand and, to a lesser extent, of the unmodified complementary strand.

[Study of the substrate-induced changes in the state of Eco dam methylase using a method of small-angle x-ray scattering].

Interaction of Ecodam methylase (E.C. 2.

[Chemico-enzymatic synthesis of genetic elements for expression of synthetic genes in Bacillus subtilis cells].

In order to obtain the recombinant Bacillus subtilis strain, a transcriptional-translational control unit of the alpha-amylase gene of B. amyloliquefaciens was synthesized. The oligodeoxyribonucleotides were prepared by the modified triester method in solution and by the solid-phase approach.

[Effect of Ecodam DNA-methylase on single-stranded sequences and synthetic oligonucleotides].

Interaction of the Ecodam methylase with different substrates were investigated among them the double- and single-stranded DNAs and synthetic oligonucleotides containing some defects in the GATC sequence. These defects were:nick, the absence of one internucleotide phosphate of nucleotide; partially single-stranded form on the recognition site etc. It was demonstrated that the presence of both G .

[Interaction of BamH1 restrictase with synthetic substrates containing complete or partial recognition sites of this enzyme].

BamHI restriction patterns of the self-complementary oligodeoxyribonucleotides were investigated. Cleavage of the oligonucleotides, containing full-length recognition site GGATCC. shows a usual type of restriction pattern.