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Biomedical subjects

V V Kuvichkin

Publications and source records attributed to V V Kuvichkin.

17 recordsLinked to original sources
PubMed2004

Increased level of beta-amyloid in the brain of bulbectomized mice.

Six weeks after bilateral olfactory bulbectomy, a peptide with molecular weight of 4 kD was revealed in extracts of the neocortex and hippocampus from mice. Using monoclonal antibodies 4G8, this peptide was identified as beta-amyloid. Its level was significantly higher in the bulbectomized animals than in sham-operated mice. The bulbectomized mice displayed sharp impairment in spatial memory when tested in the Morris water maze. The results suggest that bulbectomy initiates in the brain a pathological process similar to human Alzheimer's disease in location, biochemistry, and behavioral manifestations.

Alzheimer Disease↗
PubMed2002

DNA-membrane complexes, mitochondria and aging.

The results of extensive in vitro studies of DNA-lipid complexes allowed us to propose a model for the structure of such complexes and their involvement in the formation of DNA-membrane complexes (DMC). DMC seem to form the basis for such cellular structures as Bayer's junctions and nucleoid of bacteria, the nuclear pores, annulate lamellae and nucleoid of eucaryotes. The role of DMC in gene expression is discussed.Numerical density of mitochondria during cell aging correlates with the density of bacteria in batch culture. It is concluded that aging is caused by the unlimited growth of mitochondria and their subsequent degradation. The role of DMC in mitochondrial DNA damage at aging is discussed. The way of increasing the life span by controlling the density of mitochondria in a cell volume is likewise discussed. DMC formed between any two intracellular membranes can serve the basis for the membrane continuum in a cell.

Aging↗
PubMed2002

DNA-lipid interactions in vitro and in vivo.

The data on lipid-nucleic interactions and their role in vitro and in vivo are presented. The results of study of DNA-lipid complexes in absence and in presence of divalent metal cations (triple complexes) are discussed. The triple complexes represent the generation of cellular structures such as pore complexes of eucaryotes and "Bayer's junctions" of procaryotes. The participation of triple complexes in the formation of structure of bacterial and eucaryotic nucleoid and nuclear matrix is analysed. A model of formation of triple complexes and cellular structures and their role in DNA-lipid interactions are discussed.

Animals↗
PubMed2002

Role of lipid membrane-nucleic acid interactions, DNA-membrane contacts and metal (II) cations in origination of initial cells and in evolution of prokaryotes to eukaryotes.

The problems of the origin of primary cells and eukaryotic cells are discussed in terms of possible role of interactions between nucleic acids with lipid membrane according to corresponding original hypothesis. We propose that there are two main hypotheses of the origin of primary cells: (a). RNA appeared before proteins and DNA [Nature 213 (1967) 119]; (b). it is needed for the appearance of a primary cell, the volume closed by the lipid membrane. There was no information about the ways on how RNA appeared inside that volume for saving the reaction products around. Our hypothesis suggests that one of the starting points in the origination of primary cells was the interaction of nucleic acid and lipid membrane bubbles in the presence of metal (II) ions (which existed in high concentrations in prebiotic conditions), and this resulted in the enclosing of the pro-RNAs inside the lipid membrane. This hypothesis is formulated by us on the basis of experimental biochemical and biophysical studies of the DNA/RNA-phospholipid vesicles interactions in the presence of metal ions (II) fulfilled in the Institute of Biomedical Chemistry, RAMS, Moscow and Institute of Biophysics, RAS, Pushchino. Our belief is that DNA-membrane contacts (DNA-MCs) played an important role in the prokaryotes-to-eukaryotes transition. The model of the confluence of four prokaryotic cells may explain the prokaryotes-to-eukaryotes transition by the way of eukaryotic nuclear pore formation from prokaryotic Bayer' contacts. The main requirement for the following fusion of prokaryotic cells must be their mutual orientation. After possible association, the division of the formed cell is begun. The great advantage of the model of four prokaryotic cells is the profit in the metabolism and the possibility of the intensive growth of intercellular membrane structures.

Animals↗
PubMed1998

Role of DNA-membrane interactions in prokaryote-to-eukaryote transition: an hypothesis.

A model system of experiments to consider the problem of the origin of eukaryotic cells as well as the prokaryote-to-eukaryote transition was investigated, in terms of the role of nucleic acid-membrane interactions. It was thought worthwhile to consider the importance of DNA-membrane contacts for the organization of the prokaryotic nucleoid. The model for the fusion of four proto-eukaryotic cells was proposed to clarify the prokaryote-to-eukaryote transition as well as the formation of the nuclear pores of eukaryotes from the Bayer's junctions of proto-eukaryotes. The basic requirements following from the cell fusion model suggest such orientation of the cells involved. The obstacles for division of the ancestor cell were excluded by merging. Enormous advantages to the cell metabolism due to the fusion of four proto-eukaryotic cells and an intensive growth of the inner membranous structures resulted.

Cell Fusion↗
PubMedDate not supplied

[Effect of weak combined low frequency constant and alternative magnetic fields on intrinsic fluorescence of proteins in aqueous solutions].

It was shown that weak combined static (42 microT) and low-frequency variable (40 nT; 3-5 Hz) magnetic fields change the intensity of intrinsic fluorescence of some proteins (cytochrome c, bovine serum albumin, horseradish peroxidase, alkaline phosphatase). The effect can be interpreted as a change in the conformational state of the protein in water environment by the action of weak magnetic fields. The dynamics of the process, the concentration dependence, the binding of proteins to the fluorescence probe 1,8-ANS after treatment with magnetic fields, the frequency dependence of these reactions, and the dependence of the effect on the presence of the static constituent of the magnetic field were studied. It was shown that the changes in the intrinsic fluorescence of some enzymes (horseradish peroxidase, alkaline phosphatase) are related to changes in their functional activity. It was found that the effect is partially transferred via a solvent (water, 0.01 M NaCl) preliminarily treated with magnetic field. In the solvent, changes in its intrinsic fluorescence by the action of weak magnetic fields were also registered.

Alkaline Phosphatase↗
PubMedDate not supplied

[Effect of treated with weak magnetic field aqueous salt solutions on the intrinsic fluorescence of bovine serum albumin. Isolation from solutions and partial characterization of the biologically active fluorescing fraction].

It was shown that water with additions of Ca2+, Na+, K+ and Cl- ions preliminarily treated with weak combined constant (42 microT) and low-frequency alternating (0.06 microT) magnetic fields affects the intrinsic fluorescence of bovine serum albumin, the magnitude of the effect being dependent on the frequency of the alternating field and ionic composition of the aqueous salt solution. A practically complete transfer of the effect through a small portion of the solution treated with magnetic fields was revealed. It was also found that after magnetic treatment, the solution contains a rather large (molecular mass 700-900 D) and stable molecular associate, which possesses, at least partially, the properties and characteristics inherent in the whole solution that were as acquired as a result of magnetic treatment.

Calcium Chloride↗
PubMedDate not supplied

[Effect of weak magnetic fields on the capacity of various proteins and polyamino acids to form complexes with DNA].

It was shown that preliminary treatment of the protein component (histone H3, protamine sulfate, polyarginine) of a DNA-protein complex with weak combined (42 microT) and low-frequency (3.5-5.0 Hz) alternating (0.06 microT) magnetic fields adjusted formally to the cyclotron resonance of amino acid ions charged under natural conditions leads to substantial changes in complex formation and formation of complexes of a different type than without treatment.

Animals↗
PubMedDate not supplied

[Formation of complexes between DNA and cationic amphiphile molecules by the fluorescent probe method].

The formation of complexes of DNA with dodecylamine, dodecyltrimethylammonium, tetradecyltrimethylammonium, and hexadecyltrimethylammonium was studied using a fluorescent probe pyrene. The dependences of the spectral parameters of the hydrophobic pyrene probe on the concentration of the cationic amphiphile in the presence and absence of DNA were obtained and analyzed. It is shown that, in the absence of DNA, these dependences exhibit only one S-shaped region, which corresponds to the micelle formation of the amphiphile, whereas in the presence of DNA there are two S-shaped regions, which indicates the cooperative formation of two types of DNA-cationic amphiphile complexes. For each of the four cationic amphiphiles, the critical concentrations for the micelle formation in the absence of DNA (C0) and the concentrations at which the first (Cd1) and the second complex with DNA are formed were determined. It was found that the Cd1 value is 15-40 times lower than C0. The Cd1 value does not depend on DNA concentration and is determined only by the length of the hydrocarbon chain and the structure of the amphiphile ionic fragment. The Cd1 value increases as the length of the aliphatic chain decreases and upon replacement of mobile hydrogen atoms in the ammonium fragment by methyl groups. It was shown that hydrophobic clusters of amphiphile arising upon complex formation with DNA play the role of cross-links promoting DNA aggregation, or DNA compactization in the case of dilute solution of high-molecular weight DNA. The structures of the first and second DNA-cationic amphiphile complexes are proposed, and the mechanism and nature of interactions that determine their formation are discussed.

Amines↗
PubMedDate not supplied

[Effect of the bidistilled modified water on bovine serum albumin conformation. Fluorescent spectroscopy data].

It was shown that bidistilled modified water induces a marked decrease in the intensity of intrinsic fluorescence of bovine serum albumin and increases the binding of this protein to the fluorescent probe 1.8 ANS. These effects can be interpreted as a denaturing action of bidistilled modified water on the protein and a change in its conformational state, which is probably caused by changes in the microenvironment of the protein molecule. In addition, a substantial increase in the intrinsic fluorescence of bidistilled modified water, as compared with that of distilled water, was found.

Electrolysis↗
PubMedDate not supplied

[The role of lipid-nucleic acid interactions in the reconstruction in vitro of the nuclear shell with pores].

Previous studies of triple complexes DNA-phosphatidylcholine liposomes-Me2+ showed that, upon complexing, along with aggregation, a partial reversible fusion of liposomes takes place. In this case, DNA acts as a fusogen. The addition of the extract from Xenopus laevis or Drosophila melanogaster oocytes to the triple complex leads to a complete fusion of initial liposomes 100-200 nm in size and the formation of giant liposomes of up to 100-500 microns in size. Upon the addition of liposomes to the extract from Xenopus or Drosophila eggs, either fragments of the nuclear envelope with pores or structures like annulate lamellae are formed. The diameter of pores in these formations is approximately twice as small as in the native nuclear envelope, which may be associated with a lower surface tension of the lipid bilayer. This fact is in agreement with our model of the formation of nuclear pores suggested earlier.

Animals↗
PubMedDate not supplied

[Ultrastructural study of DNA--liposomes--Mg2+ complexes].

The structure of the triple complexes of DNA-liposomes-Mg2+ was studied by EM-cryofractography technique. The model of forming such structures and their relation to nucleus pores, mesosomes, annulate lamellae, nuclear matrix, and so-called "Bayer junctions" were shown. The role of the triple complexes in a mechanism of gene expression was discussed.

DNA↗
PubMedDate not supplied

[Interaction of natural and synthetic polynucleotides with liposomes in the presence of divalent cations].

The formation of complexes of polynucleotides (DNA, poly A.poly U) with liposomes from egg lecithins, L-alpha-phosphatidylcholine, dimirystoyl and other lipids in the presence of divalent cations was studied by differential scanning microcalorimetry circular dichroism and turbidimetry. It was shown that the secondary structure of polynucleotides (double or triple helix) was necessary for the formation of these complexes. This structure was partially destroyed during formation of complexes. It was shown, that three main types of lipids, i.e. phosphatidylcholine, phosphatidylethanolamine and sphingomyelin participate in interactions between liposomes, polynucleotides and Mg2+.

Calorimetry, Differential Scanning↗
PubMedDate not supplied

[Infrared spectroscopic study of DNA--lipid interactions. DNA compacting on disperse particles].

Within the range of relative humidity (r. h.) 0 to 92% there were obtained IR-spectra (4000--900 cm-1) of undeuterated and deuterated films of rat liver lipids, both in the free state and in the complex with native (nDNA) and heat-denaturated DNA (dDNA). Found peculiarities of IR-spectroscopic realization of the complex-formation are explained qualitatively. One of the peculiarities is hyperchromism of lipid bands and hypochromism of the bands of DNA bases. Lipids are shown to despiralize nDNA in the course of their interaction. A suggestion is advanced concerning the nature of basic contacts which form the complex DNA-lipid. It is found that nDNA unlike dDNA produces an inhibiting effect on lipids oxidation and their subsequent hydrolysis. The mechanism of the phenomenon is discussed. The ideas on DNA compactization resulting from its coiling on different protein and nonprotein particles are developed.

Animals↗
PubMedDate not supplied

[Structure and function of DNA--membrane contact in cells].

A model of DNA-membrane contact based on the postulate about the determining role of membrane RNA (mbRNA) in providing its specifitity, stability and functional activity is proposed. Proceeding from the DNA-membrane contact structure, unity and interconditionality of reduplication and transcription processes are shown, and basic peculiarities of reduplication are discussed. It follows from the analysis of lysozyme-detergent treatment that two different DNA-membrane complex preparations can be obtained: one of these upon the spheroplast - "turned inside out spheroplast" transition, the other, containing specific DNA-membrane contact only - in the course of further detergent treatment. The parameters of the spheroplast - "turned inside out spheroplast" transition can be used to characterize the native DNA-membrane complex. It is concluded that RNA that stabilizes and makes the compact form of bacterial nucletide (f-DNA) is none other than the postulated mbRNA of the cellular DNA-membrane contact.

Bacteria↗
PubMedDate not supplied

[Theoretical model of DNA-membrane contacts].

A DNA-membrane complex model (DMC) is presented, in which specific sites of DNA, low molecular weight RNA, and a system of two lipid (or lipoprotein) membranes take part, Morphological identity of these complexes and nuclear pores for eucaryotes and "Bayer's junctions" for procaryotes is suggested. The forces of membrane surface tension in DMC formation are analysed, and the diameter of nuclear pores is calculated.

DNA↗