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Biomedical subjects

N I Komarova

Publications and source records attributed to N I Komarova.

At least 19 recordsLinked to original sources
PubMed2001

Long-lived reactive intermediate photogenerated from N-(5-azido-2-nitrobenzoyl)-N'-(D-biotinyl)-1,2-diaminoethane as an affinity reagent to streptavidin.

Irradiation of a complex between N-(5-azido-2-nitrobenzoyl)-N'-(D-biotinyl)-1,2-diaminoethane (I) and streptavidin with light of 313 nm led to the covalent attachment of the photobiotin analogue I to the protein. Streptavidin could also be labelled in the dark with prephotolyzed I. These results indicate that a long-lived reactive intermediate was formed upon irradiation. Moreover, after cleavage of labelled streptavidin with proteinase K this intermediate appears to be covalently attached to the same peptide as the one obtained by direct photoaffinity labelling. An iminosulfurane II derived from the reaction of biotin sulfur atom with aryl nitrene is responsible for the dark-labelling reaction. The photoproduct II converts in an aqueous solution almost completely into N-(5-amino-2-nitrobenzoyl)-N'-(D-(S-oxo)biotinyl)-1,2-diaminoethane (the half-life of II is 10 days).

Biotin↗
PubMed2000

PAcM-AN: poly (N-acryloylmorpholine)-conjugated antisense oligonucleotides.

A new amphiphilic, high-molecular weight poly (N-acryloylmorpholine) (PAcM) polymer has been used to be linked to oligonucleotide chains through a liquid-phase stepwise synthesis. This new conjugate has been investigated for its melting property, nuclease stability and capacity to elicit RNase H activity. Its antisense activity against an HIV-1 target has been also evaluated.

Gene Expression Regulation↗
PubMed1995

Solid-phase synthesis of oligoribonucleotides using T4 RNA ligase and T4 polynucleotide kinase.

The concept of solid-phase synthesis of oligoribonucleotides using T4 RNA ligase and T4 polynucleotide kinase has been proposed and tested with model homo-oligoribonucleotides. The method consists of the immobilization of the first oligomer block at the 3'-terminus on a solid support followed by a chain elongation in the 5'-direction with trinucleoside diphosphates using T4 RNA-ligase and phosphorylation using polynucleotide kinase. Hydrazides of Biogel P-300, Sepharose 4B and cellulose were tested as solid supports for immobilization of initial oligomers. The properties of supports were rated on reactivities of immobilized 5'-phosphorylated oligomers as phosphate donors in the solid phase reactions, hydrodynamical properties and capacity to eliminate donor molecules spontaneously during reactions. Hydrazide of Sepharose 4B appeared to be a more suitable support because of better hydrodynamic properties and highest reactivities of immobilized donors. Saturated concentrations of RNA ligase and polynucleotide kinase and optimal time of joining reaction were determined. In a model experiment ApApA was twice attached to the immobilized hydrazide of Sepharose 4B donor (pA)6pAox. The yield of (Ap)12 was 25%.

Animals↗
PubMed1993

[Porphyrin derivatives of oligonucleotides. I. Synthesis of oligonucleotide derivatives bearing 2,4-di(alpha-(2-hydroxyethoxy)ethyl)- deuteroporphyrin IX or a metal complex of it and study of the oxidative modification of DNA by these derivatives].

A method for coupling 2,4-di[alpha-(2-hydroxyethoxy)ethyl] deuteroporphyrin dimethyl ether (IX), DDPOH and its complexes with metals to the 5'- or 3'-end of oligonucleotides was elaborated. In the presence of an oxidizing agent (H2O2), Fe(III)DDP-derivatives of oligonucleotides modified single-stranded DNA. The reaction was strictly site-specific and occurred at two neighbouring guanosine residues. A few types of modification were observed: cross-linking, modification leading to DNA cleavage upon piperidine treatment, and direct chain scission. The total modification yield reached 90%. Covalent attachment of Fe(III)DDP-group to oligonucleotides increased the efficiency of their uptake and the melting temperature of their complementary complexes.

Base Sequence↗
PubMed1992

[Effective complementarily-addressed photomodification of nucleic acids by oligonucleotide derivatives, containing aromatic azido groups].

Highly effective site-specific photomodification of a DNA-target was carried out with oligonucleotide reagents carrying aromatic azido groups. Oligonucleotide derivatives with a photoactive function R on the 5'-terminal phosphate and at C-5 atom of deoxyuridine were synthesized: R1NH(CH2)3NHpd(TCCACTT) and d(ULNHRCCACTT), where R1 is p-azidotetrafluorobenzoyl, R2 is 2-nitro, 5-azidobenzoyl, R3 is p-azidobenzoyl; LNH = -CH2NH-, -CH2OCH2CH2NH- or -CH2NHCOCH2CH2NH-. The prepared compounds form stable complementary complexes and effect site-specific photomodification of the target DNA. The modification of pentadecanucleotide d(TAAGTGGAGTTTGGC) with the reagents was investigated. Maximum extent of modification strongly depended on the reagent's type, the photoreagent with R1 being the most effective. Whatever the binding site was, this agent provided a 65-70% modification in all cases except LNH = -CH2NH-, when the yield was twice lower. For the reagents bearing R1 the modification sites were identified. Selective modification at the G9 residue was detected in the case of LNH = -CH2OCH2CH2NH- and when a photoactive group was linked to the terminal phosphate.

Autoradiography↗
PubMed1992

[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 7.5, and 30% acetonitrile. The temperature of the separation was a few degrees lower than Tm of corresponding oligonucleotide complexes. The diastereomers separated completely or partially were: d[GCC(Et)AAACA], d[GCCA(Et)AACA], d[GCAA(Et)ACA], d[GCC(Et)A(Et)AACA], d[GCC(Et)AA(Et)ACA], d[GCCA(Et)A(Et)ACA], d[GCC(Et)A(Et)A(Et)ACA].

Chromatography, Affinity↗
PubMed1992

Ultrastructure and biosynthetic activity of polyploid atrial myocytes in patients with mitral valve disease.

Biopsies of right auricle of human heart have been obtained during open heart surgery from 6 patients aged 23 to 49. The DNA and total protein content have been determined in isolated myocytes by two-wavelength scanning cytophotometry after double staining: Feulgen and naphthol yellow S. In all the biopsies predominant are polyploid hypertrophied myocytes. Both hypertrophied non-degenerating cells and cells with different extent of degenerative changes, primarily of myofibrils and membranes, are present. The highest extent of cell ploidy is in patients belonging to functional class IV according to the classification of New York Heart Association (NYHA); in these cases 72 to 98% of cells have nuclei with 8 c and more DNA content. With an increase in ploidy level, cells grow in size and in protein content, however the rate of this growth is much lower than that of DNA content in cells. There is no direct relation between ploidy and cell degeneration extent and no inverse relation between degeneration extent and ejection fraction.

Adult↗
PubMed1991

[Changes in the ultrastructure and DNA and protein content in human atrial myocytes in cardiac hyperfunction due to mitral valve defects].

Biopsies from human right auricles were obtained during open heart surgery, prior to valve replacement, from six patients (aged from 20 to 49 years) with rheumatic heart disease. DNA and the total protein contents were measured in isolated myocytes by means of the two wave-length scanning cytophotometry after the double Feulgen and Naphthol yellow S staining procedure. In all the biopsies polyploid hypertrophied myocytes predominate. The hypertrophic, nondegenerated cells and the cells with degenerative changes of varying severity (in the first place, changes of contractile apparatus and membranes) are present. The highest degree of cell ploidy occurs in patients of functional class IV according to the New York Heart Association classification, 72 to 98% of cells displaying octaploid and higher DNA values. With the increase in ploidy of myocytes in series 2c----4c----8c----16c----32c----64c the protein content increases only as 2.0----3.0----5.8----7.8----13.0----16.8. Neither direct correlation between the ploidy level and the degree of cell degeneration, no inverse correlation between the degree of degeneration and the value of ejection fraction was observed.

Adult↗
PubMed1984

Oligonucleotides complementary to a promoter over the region -8...+2 as transcription primers for E. coli RNA polymerase.

Primer-dependent transcription by E. coli RNA polymerase on T7 promoter A2 has been studied. Synthetic deoxyribonucleotides complementary to the promoter over the region -8...+2 were taken as primers. A ribonucleoside residue was present at the 3'-end of some of these oligonucleotides. The octanucleotide complementary to the region -8...-1 appeared to be an active primer. Oligonucleotides having lengths from 3 to 6 nucleotide residues complementary to the promoter over the region -4...+2 also exhibited primer activity. The latter was some 5-10 times greater in the case of oligonucleotides having a ribonucleoside residue at the 3'-end. Oligonucleotides which on complementary binding do not reach the center of phosphodiester bond synthesis, as well as the decanucleotides (-8...+2) and octanucleotides (-6...+2) of both the ribo- and deoxyribo-series were inactive as primers.

Base Sequence↗
PubMed1981

[Glycogen content in the DNA-synthesizing and nonsynthesizing hepatocytes of rats of different ages].

The glycogen content in DNA synthesizing and non-synthesizing hepatocytes has been conducted cytochemically during the rat postnatal development. Within all the periods of investigation, the average glycogen content in DNA synthesizing hepatocytes (phase S) are shown to be lower than that in hepatocytes being in phases G0 and G1. The absolute value of reduction of the glycogen content with diploid mononucleate hepatocytes in S-phase is almost the same for rats of all the age groups examined. The absolute value of reduction of the glycogen content in diploid binucleate hapatocytes in S-phase is twice as much as that in diploid mononucleate hepatocytes being at the same stage of the cell cycle. Regardless of the postnatal development stage and of the total glycogen content in the liver, the glycogen content in DNA non-synthesizing hepatocytes of different ploidy is in conformity with the genome number.

Aging↗
PubMed1980

[Glycogen concentration in DNA-synthesizing and non-DNA-synthesizing hepatocytes of week-old rats].

Using the combined cytochemistry, that allows to determine glycogen and DNA contents, and to localize 3H-thymidine label in one and the same cell, glycogen content was measured in both 3H-TdR-marked and 3H-TdR-non-marked hepatocytes of week-old rats. The vast majority of hepatocytes in a liver population of such rats are mononuclear 3H-TdR-non-marked cells with a 2C DNA content, which corresponds to the diploid chromosome set. The ratio of binuclear hepatocytes with diploid nuclei is in average 0.6%. At one injection of 3H-TdR, 6.6% of hepatocytes are marked in average which are almost exclusively mononuclear cells with 2c to 4c DNA content. In binuclear hepatocytes with two diploid nuclei (2c X 2), the label was seen only in single instances. The average glycogen content in S-phase hepatocytes is aproximately one third of that in hepatocytes that did not start DNA synthesis (G1 and G2 phases). The glycogen content in hepatocytes is seen reducing during S-phase. The glycogen content in G2-phase hepatocytes does not differ from that of hepatocytes before they start DNA synthesis. The availability of glycogen is not necessary for the beginning of S-phase: DNA synthesis in hepatocytes of week-old rats can start and proceed irrespective of the presence of glycogen in these. The glycogen content in binuclear hepatocytes with diploid nuclei that did not start DNA-synthesis is twice as much as in mononuclear hepatocytes before they started DNA synthesis.

Animals↗