On the role of N7 atoms of guanosine in tRNA-Phe (E. coli) in interaction with ribosomes]

The influence of alkylation of phe-tRNAPhe (E. coli) with 2',3'-O-[4-(N-2-chloroethyl-N-methylamino)-benzylidene]-uridine - 5' - methylphosphate on its ability to participate in non-enzymatic complex formation with ribosomes and poly-U was investigated. Phe-tRNAsPhe, containing alkylated guanosines at different positions, including anticodone, are active in binding with ribosomes. It is concluded, that N7 nitrogens of guanosine of the tRHAPhe are not elements, significant for the interaction with ribosomes.     

High-frequency electrospectroscopy of human whole blood with different degrees of oxygen saturation

The electric properties of normal human blood were measured at 1.0-2.0 MHz frequency range. The dependence of relaxation time of the erythrocyte membranes on the degree of hemoglobin molecules saturation with oxygen was obtained.     

A comparative study of the immunogenicity of 2 group-B meningococcal vaccines in monkeys

The comparative study of two group B meningococcal vaccines manufactured in the USSR and in Cuba was made. The vaccine manufactured in the USSR contained the noncovalent compound of group B Neisseria meningitidis polysaccharide and outer membrane protein, and the Cuban vaccine contained group B N. meningitidis outer membrane proteins and group C N. meningitidis polysaccharide. The data obtained in this study indicated that both vaccines possessed immunological potency evaluated according to their capacity to stimulate the formation of bactericidal antibodies, whose level was found to increase eightfold after the immunization of monkeys in two injections. Besides, group B meningococcal vaccines did not induce the suppression of nonspecific protective activity characteristics of the body and did not stimulate the formation of autoantibodies to brain and liver tissues, which was indicative of the safety of these vaccines.     

The relationship between ischemic preconditioning-induced infarction size limitation and duration of test myocardial ischemia

Traditionally infarction size reduction by ischemic preconditioning is estimated in duration of test ischemia. This approach limits the understanding of real antiischemic efficacy of ischemic preconditioning. Present study was performed in the in vivo rat model of regional myocardial ischemia-reperfusion and showed that protective effect afforded by ischemic preconditioning progressively decreased with prolongation of test ischemia. There were no statistically significant differences in infarction size between control and preconditioned animals when the duration of test ischemia was increased up to 1 hour. Preconditioning ensured maximal infarction-limiting effect in duration of test ischemia varying from 20 to 40 minutes.     

Starburst Conjugates of Proteins with Carbon-Chain Polymers Containing Low Molecular Biologically Active Compounds: Synthesis and Immunogenicity

The synthesis of starburst polymer–protein conjugates on the basis of bovine serum albumin and horseradish peroxidase was performed with the aim to study the possibilities of regulation of the immune response against the components of the conjugates. These polymers had one-point binding between the protein and the modifying carbon-chain polymer that contained 1-vinyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (a salsolinol analogue) or bradykinin (peptide hormone) residues in its carbon chain. Changes in the chemical nature of the carbon-chain part of the polymer–protein conjugate were shown to increase or decrease the level of antibody production both against the low-molecular compounds attached to the polymeric fragments and against the protein carrier.     

Modular organization of FDH: Exploring the basis of hydrolase catalysis

An abundant enzyme of liver cytosol, 10-formyltetrahydrofolate dehydrogenase (FDH), is an interesting example of a multidomain protein. It consists of two functionally unrelated domains, an aldehyde dehydrogenase-homologous domain and a folate-binding hydrolase domain, which are connected by an approximately 100-residue linker. The amino-terminal hydrolase domain of FDH (Nt-FDH) is a homolog of formyl transferase enzymes that utilize 10-formyl-THF as a formyl donor. Interestingly, the concerted action of all three domains of FDH produces a new catalytic activity, NADP+-dependent oxidation of 10-formyltetrahydrofolate (10-formyl-THF) to THF and CO2. The present studies had two objectives: First, to explore the modular organization of FDH through the production of hybrid enzymes by domain replacement with methionyl-tRNA formyltransferase (FMT), an enzyme homologous to the hydrolase domain of FDH. The second was to explore the molecular basis for the distinct catalytic mechanisms of Nt-FDH and related 10-formyl-THF utilizing enzymes. Our studies revealed that FMT cannot substitute for the hydrolase domain of FDH in order to catalyze the dehydrogenase reaction. It is apparently due to inability of FMT to catalyze the hydrolysis of 10-formyl-THF in the absence of the cosubstrate of the transferase reaction despite the high similarity of the catalytic centers of the two enzymes. Our results further imply that Ile in place of Asn in the FDH hydrolase catalytic center is an important determinant for hydrolase catalysis as opposed to transferase catalysis.     

Molecular-genetic markers in lung cancer diagnostics

The major approaches to different lung cancer marker development are outlined in the review, including genetic, epigenetic, protein, transcryptomic, proteomic, metabolic, and miRNA markers. As far as epigenetic changes are among the earliest events in malignant transformation, methylated markers are thoroughly discussed. Special attention is given to minimally invasive tumor markers, which could be detected in easily accessible biological fluids, because they can be useful for screening and early diagnostics of cancer (before its clinical manifestation) as well as for verification of standard methods of diagnostics. Extracellular nucleic acids, circulating in blood (cirNA), are highlighted as the potential source of material for the early lung cancer diagnostics, prediction of antitumor treatment efficiency, post-treatment monitoring and disease prognosis.     

Complementary addressed modification of plasmid DNA

The possibility to accomplish the sequence-specific chemical modification of superhelical DNA with reactive oligonucleotide derivatives was demonstrated. Plasmids containing fragments of the immunoglobulin gene were modified with alkylating derivatives of oligonucleotides complementary to a nucleotide sequence in the immunoglobulin gene. In contrast to the relaxed plasmid DNAs, superhelical DNAs (sigma = -0.1) were found to be attacked by the derivatives at the target nucleotide sequence. The efficiency of the reaction increases with the increase of the plasmids negative superhelicity. It was found also that the denatured derivatives. The sequence-specific modification of plasmid DNAs with the reactive oligonucleotide derivatives can be used for the site-directed mutagenesis and the investigation of the repair processes.