Showing papers by "Moscow State University published in 1970"
TL;DR: This work has shown that 6-MeAde and certain N2-methylated derivatives of guanine have been recently discovered in appreciable amounts in bovine and human sperm DNA.
Abstract: THE rare bases which occur in animal DNA deserve special attention because their presence is directly relevant to questions concerning the cellular, subcellular and species specificity of DNA methylation. In animal DNA, the base 5-methylcytosine (5-MeCyt) is usually detected1,2. Numerous attempts to find N6-methyladenine (6-MeAde)—which is characteristic of the DNA of various microorganisms3–5—in animal DNA proved unsuccessful3,6–9. This may be accounted for by the fact that animal cells do not contain the enzymes required for methylating DNA at adenine residues7–9. Nevertheless, 6-MeAde and certain N2-methylated derivatives of guanine have been recently discovered in appreciable amounts in bovine and human sperm DNA10. Our present knowledge on the specificity of DNA methylation in animal cells is not only scanty but also contradictory.
351 citations
TL;DR: Effects of metaphase inhibitors on mouse and human embryonic, fibroblast-like cells growing on glass and on an oriented substrate (fish scale) and the formation of microtubules as the possible structural basis of the stabilization of the non-active state of the cell surface is discussed.
Abstract: Effects of metaphase inhibitors (colcemid, colchicine, vinblastine) on mouse and human embryonic, fibroblast-like cells growing on glass and on an oriented substrate (fish scale) were studied. All three inhibitors caused similar changes in the form of interphase cells and inhibited their directional locomotion. The effects of two inhibitors (colcemid and vinblastine) were found to be completely reversible. Microcinematographic studies have shown that the most conspicuous change of locomotory behaviour induced by colcemid was the disappearance of non-active stable parts of the cell edge; in normal cells only the leading part of the edge was actively moving, while in colcemid-treated cells all parts of the edge eventually became active. Activation of the whole edge made these cells unable to perform directional translocation. It is suggested that colcemid and other metaphase inhibitors prevent stabilization of the non-active state of the cell surface. The possible role of this suggested colcemid-sensitive stabilization mechanism in the normal locomotory behaviour of fibroblasts is discussed. Electron-microscopic examination has shown that microtubules disappeared from the cytoplasm of colcemid-treated, mouse, fibroblast-like cells. The formation of microtubules as the possible structural basis of the stabilization of the non-active state of the cell surface is discussed.
326 citations
TL;DR: It was concluded that a mechanism for ion accumulation in submitochondrial particles is specific for the sign of the charge but not for other features of the penetrating compounds.
297 citations
TL;DR: It is shown that anions of phenyl dicarbaundecaborane (PCB − ) are extruded from mitochondria on transition to the energized state, and the conclusion is confirmed that it is the electric field (negative inside the mitochondria) which is the motive force for the transport of penetrating ions across the mitochondrial membrane.
235 citations
TL;DR: Evidence has been presented that blue-green alga Anacystic nidulans can undergo genetic transformation and favourable conditions for transformation have been described with respect to the revealing of transformants, the concentration of DNA and the competence of cells.
Abstract: Evidence has been presented that blue-green alga Anacystic nidulans can undergo genetic transformation DNA from erythromycin-, streptomycin-resistant of filamentous strains has been found to transform appropriate markers to a wild type or some other recipients Favourable conditions for transformation have been described with respect to the revealing of transformants, the concentration of DNA and the competence of cells
190 citations
TL;DR: It is concluded that penetrating ions move in the electric field orientated across energy-producing membranes and supported by electron and hydrogen transfer or ATP hydrolysis.
183 citations
145 citations
137 citations
TL;DR: In this article, the 13C NMR absorption spectra of 50 bicyclic hydrocarbons, alcohols and ketones have been measured, in addition to some terpenes.
Abstract: 13C NMR absorption spectra of 50 bicyclic hydrocarbons, alcohols and ketones have been measured, in addition to some terpenes. The 13C chemical shifts are approximately additive for similar compounds and can be used for the determination of molecular structure; they differ for endo- and exo-isomers, just as in proton spectra. These quite regular and predictable 13C shift differences are much larger and are caused by the 1,4-nonbonded interaction between atoms heavier than hydrogen, not by magnetic anisotropy effects.
122 citations
TL;DR: In this paper, an exponential optical tail is attributed to the influence of the random force field present in a disordered system and the interband absorption coefficient is calculated for the frequency range, ω, below the threshold value (optical tail).
Abstract: The interband absorption coefficient is calculated for the frequency range, ω, below the threshold value (“optical tail”). The tail is attributed to the influence of the random force field present in a disordered system. Two cases are considered: that of the “smooth” random field possessing a correlation function which is continuous and differentiable as many times as needed and that of the Coulomb field produced, for example, by randomly distributed charged centres. In both cases an exponential optical tail is obtained for a sample which is in a certain sense nearly intrinsic: In α ∼ – (Δ – ħ ω)/ω, where Δ is the band gap that would have been observed without fluctuations of the force field and ω is some characteristic energy. The tail is correlated with the density of states tail but does not reproduce it, the latter being Gaussian in the same energy range. In the most interesting case the formation of an optical tail is due to quantum effects in contrast to the density of states tail which may be obtained in a purely classical approximation as well. In the Coulombic case an explicit form of the dependence of ω on impurity concentration n is obtained ω ∼ n2/5. This seems to be in agreement with the experimental data available.
Der Interband-Absorptionskoeffizient wird fur den Frequenzbereich unterhalb des Schwellwertes (optischer Auslaufer) berechnet. Der Auslaufer wird dem Einflus des „random-force” Feldes, das in fehlgeordneten Systemen vorhanden ist, zugeschrieben. Zwei Falle werden berucksichtigt: der eines „glatten” „Random”-Feldes mit einer Korrelationsfunktion, die kontinuierlich und beliebig oft differenzierbar ist, und der eines Coulombfeldes, das zum Beispiel durch beliebig verteilte geladene Zentren verursacht wird. In beiden Fallen wird ein exponentieller optischer Auslaufer fur eine Probe erhalten, die in einem gewissen Sinne nahezu grundgitterahnlich ist: In α ∼ – (Δ – ħ ω)/ω, wobei Δ die Bandlucke, die ohne Fluktuationen des Kraftfeldes beobachtet werden wurde, und ω eine charakteristische Energie ist. Der Auslaufer ist mit dem Auslaufer der Zustandsdichte verknupft, reproduziert diesen, der in dem gleichen Energiebereich vom Gausstyp ist, jedoch nicht. In dem am meisten interessierenden Fall wird die Bildung eines optischen Auslaufers durch Quanteneffekte verursacht im Gegensatz zum Auslaufer der Zustandsdichte, der auch in der rein klassischen Naherung erhalten wird. Fur den Coulomb-Fall wird eine explizite Form der ω-Abhangigkeit von der Defektkonzentration n zu ω ∼ n2/5 erhalten. Diese scheint mit den erhaltlichen experimentellen Werten ubereinzustimmen.
107 citations
TL;DR: There is an energy-dependent charge-specific mechanism for anion accumulation in the chromatophore membrane resembling that found in the membrane of submitochondrial particles, and the electric field is the motive force for ion transfer through the chromatography membrane against a concentration gradient.
TL;DR: In this article, an equation for the electrode charge in the presence of adsorbed organic molecules is suggested and analyzed; from this Frumkin's, Hansen's and Parsons' models, discussed earlier in the literature, can be derived under particular conditions.
TL;DR: In this article, the notion of the charge has been considered for the case of an ideally polarized electrode, and a definition of the total charge is given, equally applicable to ideally polarized and reversible electrodes, as the amount of electricity to be supplied to the electrode to keep the electrode potential constant when its surface is increased by unity and the composition of the bulk phases of the system is maintained constant.
TL;DR: In this paper, the phase relations in the ZrO2Sc2O3 system have been investigated by the methods of high-temperature X-ray analysis, dilatometry, differential thermal analysis, and electrical conductivity measurements in the composition range 3 −40 mol % Sc 2O3 and the temperature range 20 −2000°C.
TL;DR: The present paper summarizes the results of the study of the same problem by using synthetic ionized compounds readily penetrating across lipid membranes to form an electric field coupling electron transfer and phosphorylation in biological membranes.
TL;DR: It is concluded that the steric closeness of such synthetic “enzyme-substrate complexes” may give rise to formation of new internucleotide linkages, and one may hope that this principle may become a basic one for the self-assembly of oligonucleotides to form double-stranded polynucleotide.
Abstract: Publisher Summary This chapter deals with synthetic nucleotide-peptides, with phosphoamide and phosphoester bonds. It reviews that synthetic nucleotide-peptides proves to be very useful in elucidating the mode of action of enzymes of nucleotide exchange from the point of view of the activation of the phosphate residue of the mononucleotide, as well as from that of noncovalent interactions between the nucleotide and the active center of enzymes. Application of physical methods for the study of noncovalent interactions in the molecules of model nucleotide-peptides with closely arranged amino acid radicals and heterocyclic bases, open new perspectives for investigation of the structural arrangement of nucleoproteins in ribosomes and viruses. Besides, synthetic nucleotide-(P-N)-peptides are also useful for elaborating a model for the enzymatic synthesis of internucleotide linkages, as these compounds have some features of enzyme–substrate complexes. It concludes that the steric closeness of such synthetic “enzyme-substrate complexes” may give rise to formation of new internucleotide linkages. One may hope that this principle may become a basic one for the self-assembly of oligonucleotides to form double-stranded polynucleotides.
TL;DR: In this article, the authors have tried to show that molecular gas and liquid chromatography on adsorbents have a number of advantages for analytical and preparative applications, and they have developed a molecular theory of gas adsorption possible on the basis of molecular-statistics and semi-empirical or effective potential functions of intermolecular interactions.
TL;DR: The inhibitory action of a homologous series of n-alkylboronic acids H(CHz)nB(OH)z isribes in the a-chymotrypsincatalysed hydrolysis of some synthetic substrates, and the inhibitory properties depended on the length of the alkyl chain.
TL;DR: In this article, various types of electron transitions in strong magnetic fields due to qualitative changes of the energy spectrum of electrons (and hence of properties of materials) were predicted and observed at certain critical values of the magnetic field.
Abstract: Various types of electron transitions in strong magnetic fields due to qualitative changes of the energy spectrum of electrons (and hence of properties of materials) were predicted and observed at certain critical values of the magnetic field. Metallic and semiconducting Bi-Sb alloys were investigated in the concentration range of Sb up to 8 at % and from 8 at % to 16 at % correspondingly. The transversal and longitudinal magnetoresistance measurements on Bi-Sb alloy single crystals were performed at various orientations of current and fields relative to the crystalline axes. The measurements were performed in magnetic fields up to 600 kOe.at temperatures from 4.2 to 77°K. The following types of electron transitions were discovered: (a) semiconductor-metal transition; (b) a transition from a semiconducting state into a state with an abnormally small energy gap between the zones referred to as a “quasimetallic”; (c) a transition semiconductor-“quasimetal”-semiconductor; (d) a transition semiconductor-“quasimetal”-semiconductor-metal; and (e) metal-semiconductor transition.
TL;DR: The possibility of mapping leakage places by means of the SP method has been discussed by the authors in an earlier report as discussed by the authors, and detailed measurements of the natural electric field allow to determine the seepage rates from individual areas of a water reservoir in relative units.
Abstract: Water seepage from reservoirs causes appreciable anomalies of natural electric fields. The possibility of mapping leakage places by means of the SP method has been discussed by the authors in an earlier report. Further work has shown that detailed measurements of the natural electric field allow to determine the seepage rates from individual areas of a water reservoir in relative units. If data on the total discharge from a water reservoir are available, the conventional seepage units can be converted into absolute ones. Using this technique on a water reservoir in Armenia has permitted to control the change of the leakage rate as hydroinsulation operations were in progress. It has been established that as a result of shielding the bottom with clay material leakage from the central part of the reservoir has stopped. On the other hand, construction of cement seepage-proof protection has had so far no appreciable positive effect.
TL;DR: The spontaneous act of locomotion in cats depends on the type of prepara t ion and is low in cats af ter p reco l l i eu la r d e c e r e b r a t i e n b u t cons iderab le in thalamic cats.
Abstract: The act ivi ty of re t iculospinal neurons in the pons and medul la was r e corded in t race l lu la r ly . Their spontaneous act ivi ty depends on the type of prepara t ion . It is low in cats af ter p reco l l i eu la r d e c e r e b r a t i e n b u t cons iderab le in thalamic cats . Removal of the ce rebe l lum reduces spontaneous act ivi ty. Most re t icu lospina l neurons respond monosynapt ieal ly to s t imulat ion of two regions in the b r a i n s t e m f r o m which locomotion can be evoked, the \" l ocomoto r r eg ion\" of the meseneephalon and pos t e r io r hypothalamus.
TL;DR: In this article, different methods of deducing the basic equation of the thermodynamic theory of electrocapillarity for hydrogen-adsorbing metals are compared and the relations that determine the value of the isoelectric potential shift under different conditions, as well as the importance of the dependence of the potential on the solution pH, the free charge remaining constant, have been deduced and experimentally verified.
TL;DR: In this paper, the acidities of some fluorinated hydrocarbons, R F H, have been estimated by polarographic method by using electrochemical data on electrochemical reduction of (R F ) 2 Hg have been correlated with rate constants of hydrogen isotopic exchange in R FH in methanol.
TL;DR: In this paper, the translationally invariant shell model was considered and the fractional parentage coefficients were calculated for the 3(A − 1) Jacobi coordinates. But the problem of the spurious states is absent in this model.
TL;DR: In this article, the authors studied hybrid virus formation in mixed reconstitution experiments with RNA isolated from different plant viruses and the proteins from tobacco mosaic virus (TMV), cucumber virus 4 or barley stripe mosaic virus.
TL;DR: In this paper, the authors used the reflected wave method for determining the depth of seepage flow in the dam supporting mass, which can be also achieved by electrical sounding and induced polarization methods.
Abstract: Earth dams are constructed on a wide scale for hydrotechnical and reclamative purposes. However, the great water permeability of soils and their bad gradation are frequently responsible for the development of mechanical suffusion and other phenomena resulting in dam destruction.
Geophysical observations allow under certain conditions to forecast the development of adverse factors. They thus are, as practice shows, an important tool to observe the technical status of dams.
The difference in propagation velocities of elastic waves in the zone of aeration and full saturation determines the applicability of the reflected wave method for determining the depth of seepage flow in the dam supporting mass. This can be also achieved by electrical sounding and induced polarization methods since the resistivity and polarizability of air-dry and water-saturated grounds differ considerably.
Maps of equal potentials measured on the dam slope reflect the configuration of the contours of water table of the water flow passing through the dam. This makes it possible to obtain data on the direction and intensity of flow as well as on the presence of heterogeneous grounds filling the dam supporting mass. Besides, regime observations conducted according to the SP method allow to forecast the development of suffusion and observe the redeposition of grounds. If the SP anomalies do not increase with time, the suffusion processes can be regarded as fading out. Enhanced amplitude and increasing areas of anomalies show the intensification of these processes.
Combined application of some of the above mentioned methods allowed to obtain many practical results on a number of dams in Transcaucasia and Central Asia. The true position of the depression surface determined in the dam of one of the high-mountain water reservoirs, for instance, considerably differed from the designed one. The configuration of the seepage flow surface and its fluctuation caused by the rise and drop of the water level in the reservoir have been studied in detail on another dam situated on a plain. The sites of the most intensive outwash of fine material have also been located and the processes of soil redeposition in the dam supporting mass characterized. The data of the geophysical investigations were used to plan hydroinsulation and repair work.
TL;DR: In this article, the concept of pseudo-injective modules is introduced and its properties are examined as are those of the class of torsion-free modules in the sense of H. Bass over self-pseudo-injection rings.
Abstract: The concept of a pseudo-injective module is introduced; its properties are examined as are those of the class of torsion-free modules in the sense of H. Bass over self-pseudo-injective rings.
TL;DR: The results of changes in OA of transketolase arising on TPP interaction with apoenzyme are reported.
TL;DR: Comparisons suggest that thiamine pyrophosphate, coenzyme of transketolase, interacts with tryptophanyl residue in the active centre of apoenzyme, which is supposed to be that of charge transfer complex formation.