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S A Kuznetsov

Publications and source records attributed to S A Kuznetsov.

At least 73 records · Page 4Linked to original sources
PubMed1981

[Formation of foci of myeloid cells on colonies of thymus and bone marrow fibroblasts in monolayer cultures].

A culture system favouring myeloid cell formation directly on the surface of mouse stromal fibroblast colonies has been developed. It has been shown that the plaques formed are both much more numerous and essentially larger on stromal fibroblast colonies of thymus than of bone marrow origin. Consequently, hemopoietic precursor cells that form the myeloid plaques in the monolayer cultures interact dissimilarly with stromal mechanocytes of different origin.

Animals↗
PubMed1981

[Interaction of myeloid cells with stromal fibroblasts in monolayer cultures].

Stromal fibroblasts of bone marrow, spleen and thymus origin as well as fibroblasts of peritoneal fluid origin are shown to have no difference in the ability to bind morphologically distinguishable granuloid cells in monolayer cultures. On the contrary, thymus fibroblast colonies encourage the development of myeloid cell plaques (which are formed by bone marrow hemopoietic precursor cells) a great deal stronger than do bone marrow and peritoneal fluid fibroblast colonies. It means that their different origin may be revealed when they interact with hemopoietic precursor cells but not with differentiated myeloid cells.

Animals↗
PubMed1980

High molecular weight protein MAP 2 promoting microtubule assembly in vitro is associated with microtubules in cells.

Brain high molecular weight (HMW) protein promoting microtubule assembly in vitro and identical to MAP 2 (one of the proteins which copurify with tubulin through microtubule assembly-disassembly cycles), is shown to be associated with microtubules in interphase and mitotic cells. This HMW protein was purified earlier (Kuznetsov et al., 1978), directly from bovine brain without previous obtaining total microtubule protein. Now we have obtained a monospecific antibody against it. Identity of the HMW protein with MAP 2 is inferred from SDS-electrophoresis and immunological tests; its intracellular localization is determined by indirect immunofluorescent staining of cultured bovine tracheal epithelium. the anti-MAP 2 antibody stains the same structures in the cells as the tubulin antibody: it stains the fibrillar network in interphase cells, mitotic spindle, and the stem body. No fibrillar structures in the cells treated with colchicine or vinblastine were stained with the antibody against MAP 2. Anti-MAP 2 also stains tubulin-containing paracrystals which have been formed in the vinblastine-treated cells. Therefore HMW protein MAP 2 which promotes tubulin polymerization in vitro is associated with microtubules in vivo.

Animals↗
PubMed1979

[Reaction between the mechanocytes of hematopoietic organs in collagen gel].

Interactions between stromal mechanocytes of hemopoietic organs were studied at their cultivation in three-dimentional collagen gel. It was demonstrated that cellular cords appearing between fibroblast colonies and between fragments of hemopoietic organs are of fibroblastic nature. They are not resulted from organic or specific peculiarities, or from discharge of substances attracting fibroblasts. A linear dependence between the amount of fibrorow or spleen was noted. Fibroblast colonies formed by the hamster bone marrow and splenic cells, as well as by passaged fibroblasts of the guinea pig bone marrow were obtained. In order to form colonies by the passaged fibroblasts it is necessary to add of irradiated cells. Its effect, besides the medium conditioning, is evidently, in restriction of fibroblast mobility in collagen gel.

Animals↗
PubMed1979

[Hematopoietic and lymphoid cell adhesion to stromal mechanocytes in vitro].

In vitro adhesion of guinea pig bone marrow and spleen cells to cultured fibroblasts of bone marrow, spleen, thymus and peritoneal fluid origin was studied. Much better binding of myeloid cells to fibroblasts than to macrophages was observed, but no difference in adhesion to stromal fibroblasts of different origin was focund. The number of adhereing cells per one stromal mechanocyte depends on the number of adhesion sites on the surface of target cells. According to our data, adhesion sites for myeloid cells are much more numerous, than adhesion sites for lymphoid cells.

Animals↗
PubMed1978

[Dynamics of the restoration of a population of peritoneal mast cells following their destruction].

Removal of the mast cells from the mouse abdominal cavity by repeated washings as well as their osmotic destruction with distilled water are suitable methods to study regeneration of mast cells in postnatal ontogenesis. Simultaneous application of their differential staining with alcian blue-safranin makes it possible to reveal successive stages of the newly formed mast cells maturation and determine duration of every stage. The time of complete renovation of the peritoneal mast cells has been stated to be, according to the mode of the stimulation, 60--80 days. Total duration of the first two stages of maturation is 1--2 days. Mast cell differentiation is fully completed by the 11th day.

Animals↗
PubMedDate not supplied

[New non-hydrolyzable substrate analogs for 8-oxoguanine-DNA glycosylases].

8-Oxoguanine-DNA glycosylases play a key role in the repair of oxidatively damaged DNA. The Escherichia coli formamidopyrimidine-DNA glycosylase (Fpg) and human 8-oxoguanine-DNA glycosylase (hOGG1) are DNA base excision repair enzymes that catalyze the removal of 7,8-dihydro-8-oxoguanine (oxoG) residue, and cleave DNA strand. Specific contacts between DNA phosphate groups and amino acids from active centers of these enzymes play a significant role in DNA-protein interactions. In order to design new non-hydrolyzable substrate analogs of Fpg and hOGG1 for structural studies modified DNA duplexes containing pyrophosphate or OEt-substituted pyrophosphate internucleotide (SPI) groups near the damage were tested. We showed that enzymes recognize and specifically bind to DNA duplexes obtained. The mechanism of incision of oxoG by the Fpg and hOGG1 was determined. We revealed that both enzymes were not able to excise the oxoG residue from DNA containing modified phosphates immediately 3' to the oxoG. In contrast, Fpg and hOGG1 effectively incise DNA duplex carrying analogous phosphate modifications 5' to the oxoG. Non-cleavable oxoG-containing DNA duplexes bearing pyrophosphate or substituted pyrophosphate groups immediately 3' to the oxoG are specific inhibitors for both 8-oxoguanine-DNA glycosylases and can be used for structural studies of complexes comprising a oxoG-containing DNA bound to catalytically active wild-type enzymes as well as their pro- and eucaryotic homologs.

DNA↗
PubMedDate not supplied

[45 kDa fragment of the kinesin molecule possesses high ATPase activity and binds to microtubules].

Kinesin is a mechano-chemical ATPase capable to move particles along microtubules and microtubules along the solid substrate. Molecule of bovine brain kinesin is a heterotetrameric unit consisting of two heavy (120 kDa) and two light (62 kDa) chains. We used limited proteolysis to study the location of the functional sites on the kinesin molecule. Chymotrypsin cleavage produced a stable 45 kDa fragment of the heavy chain which was purified from the digest using FPLC chromatography on a Superose 12 column. 45 kDa fragment contained both a microtubule-binding site and a ATPase site of the kinesin molecule. Cleavage of the 45 kDa fragment from the rest of the heavy chain significantly activated its ATPase activity. However, this activity remained fully dependent on microtubules. We suggest that the chymotrypsin cleavage uncouple ATPase activity of kinesin (found in the 45 kDa fragment) from its translocator activity (which, probably, required the presence of other parts of the molecule).

Adenosine Triphosphatases↗
PubMedDate not supplied

[Isolation and various properties of nucleoside monophosphate kinases from Escherichia coli].

A technique is proposed for isolation of nucleosidemonophosphate kinases--AMP-kinase (EC 2.7.4.11), GMP-kinase (EC 2.7.4.8), CMP-kinase (EC 2.7.4.14), UMP-kinase (EC 2.7.4.14) and TMP-kinase (EC 2.7.4.9)--from E. coli MRE-600. It involves cell destroying, precipitation of nucleic acids with polyethyleneimine, fractionation with ammonium sulphate followed by chromatography on different carriers (DEAE-Toyopearl-650 M, Matrex gel Blue A, Matrex gel Red A). The technique enables all the five enzymes to be obtained separately and without contaminations with nucleotide dephosphorylating enzymes. For all the enzymes the pH optimum was found to range from 6.5 to 8.0, and Mg2+ ions were found to be the best activator for all the enzymes studied. The substrate specificity was investigated with respect to acceptors and donors of the phosphate groups. The enzymes showed strict specificity to the heterocyclic base of the acceptor phosphate group. AMP-, GMP- and CMP-kinases phosphorylated the corresponding deoxynucleoside monophosphates less effectively than ribonucleoside monophosphates. ATP was found to be the most effective phosphate donor for all the enzymes under study.

Chromatography, Agarose↗