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Showing papers by "Russian Academy of Sciences published in 1979"


Book ChapterDOI
TL;DR: The chapter discusses the stability of proteins and presents the results obtained on small compact globular proteins, which represent one single cooperative system, and the temperature-induced changes in protein, denaturational and predenaturational changes inprotein, thermodynamics of protein unfolding, and thermodynamic properties of protein.
Abstract: Publisher Summary The chapter discusses the stability of proteins and presents the results obtained on small compact globular proteins, which represent one single cooperative system. Protein is a cooperative system and behaves in an all-or-none fashion. Sharp changes in the properties of a protein do not mean anything in themselves because sequential multistep transitions exhibit the same sharp sigmoidal changes in the observed parameters. The problem of stability of native proteins is closely connected with the problem of protein denaturation, as stability can be judged only by breaking the native structure—that is, denaturing protein by various treatments. The pH of the solution is one of the most important factors determining the state of a protein. Potentiometric titration of protein revealed that smooth changes are connected with the titration of groups with a pK not very different from that of free amino acids, while the gross conformational changes associated with pH denaturation are accompanied by the unmasking of buried groups. The chapter also discusses the temperature-induced changes in protein, denaturational and predenaturational changes in protein, thermodynamics of protein unfolding, and thermodynamic properties of protein.

2,037 citations


Journal ArticleDOI
TL;DR: In this article, an approximate solution of the problem for a soft elastic inclusion in an elastic half-space is presented. But the authors assume that the moduli of the inclusion differ slightly from those of the surrounding medium (by no more than 30%).
Abstract: During the earthquake preparation a zone of cracked rocks is formed in the region of a future earthquake focal zone under the influence of tectonic stresses. In the study of the surrounding medium this region may be considered as a solid inclusion with altered moduli. The inclusion appearance causes a redistribution of the stresses accompanied by corresponding deformations. This paper deals with the study of deformations at the Earth's surface, resulting from the appearance of a soft inclusion. The Appendix contains an approximate solution of the problem for a soft elastic inclusion in an elastic half-space. It is assumed that the moduli of the inclusion differ slightly from those of the surrounding medium (by no more than 30%). The solution permits us to calculate the deformations at the Earth's surface for the inclusion with an arbitrary heterogeneity and anisotropy. The problem is solved by the small perturbation method. The calculation is made for a special case of a homogeneous isotropic inclusion where only the shear modulus decreases. The shear stresses act at infinity. The equations are deduced for the estimation of deformations and tilts at the Earth's surface as a function of the magnitude of the preparing earthquake and the distance from the epicentre. Comparison has shown a satisfactory agreement between the theoretical and field results. Let us assume that the zone of effective manifestation of the precursor deformations is a circle with the centre in the epicentre of the preparing earthquake. The radius of this circle called ‘strain radius’ may be calculated from the equation $$\rho = 10^{0.43M} km,$$ where M is the magnitude. It was shown that the precursors of other physical nature fall into this circle.

908 citations


Journal ArticleDOI
TL;DR: In this article, a strong correlation exists between percent TiO 2 (proportional to amount of melting) and Al 2 O 3 /TiO 2, CaO/TiO2 ratios of these close to primary MORB, indicating a progressive release of Al and Ca from the mantle source.

693 citations


Journal ArticleDOI
TL;DR: In this article, it is shown that at a sufficiently large temperature a phase transition takes place after which almost all elementary particles in the hot super-dense matter become massless and weak interactions become long-range like electromagnetic interactions.
Abstract: Reviews phase transitions in super-dense matter, which consists of particles interacting in accordance with the unified gauge theories of weak, strong and electromagnetic interactions It is shown that at a sufficiently large temperature a phase transition takes place after which almost all elementary particles in the hot super-dense matter become massless and weak interactions become long-range like electromagnetic interactions Analogous phenomena may take place with an increase of fermion density in cold dense matter, and also in the presence of external fields and currents Phase transitions in gauge theories lead to a time dependence of the masses of particles, of coupling constants and of the cosmological term in the expanding Universe, to the appearance of a domain structure of vacuum, to substance energy non-conservation, to a possibility of obtaining the 'hot' Universe starting with a 'cold' one, and to some other unusual effects important for cosmology and for elementary particle physics

605 citations


Book
01 Jan 1979
TL;DR: The Chemical Structures and Properties of Condensed Inorganic Polyphosphates, and Methods of Extraction from Biological Materials, are presented.
Abstract: Foreword to the First Edition.Preface.Acknowledgements.Introduction.1 The Chemical Structures and Properties of Condensed Inorganic Phosphates.1.1 The Structures of Condensed Phosphates.1.1.1 Cyclophosphates.1.1.2 Polyphosphates.1.1.3 Branched Inorganic Phosphates, or 'Ultraphosphates'.1.2 Some Chemical Properties of Condensed Inorganic Polyphosphates.1.3 Physico-Chemical Properties of Condensed Inorganic Polyphosphates.2 Methods of Polyphosphate Assay in Biological Materials.2.1 Methods of Extraction from Biological Materials.2.2 Chromatographic Methods.2.3 Colorimetric and Fluorimetric Methods.2.4 Cytochemical Methods.2.5 X-Ray Energy Dispersive Analysis.2.6 31P Nuclear Magnetic Resonance Spectroscopy.2.7 Other Physical Methods.2.8 Gel Electrophoresis.2.9 Enzymatic Methods.3 The Occurrence of Polyphosphates in Living Organisms.4 The Forms in which Polyphosphates are Present in Cells.4.1 Polyphosphate-Cation Complexes.4.2 Polyphosphate-Ca2+-Polyhydroxybutyrate Complexes.4.3 Complexes of Polyphosphates with Nucleic Acids.4.4 Binding of Polyphosphates with Proteins.5 Localization of Polyphosphates in Cells of Prokaryotes and Eukaryotes.5.1 Prokaryotes.5.2 Eukaryotes.6 Enzymes of Polyphosphate Biosynthesis and Degradation.6.1 Enzymes of Polyphosphate Biosynthesis.6.1.1 Polyphosphate Kinase (Polyphosphate:ADP Phosphotransferase, EC 2.7.4.1).6.1.2 3-Phospho-D-Glyceroyl-Phosphate:Polyphosphate Phosphotransferase (EC 2.7.4.17).6.1.3 Dolichyl-Diphosphate:Polyphosphate Phosphotransferase (EC 2.7.4.20).6.2 Enzymes of Polyphosphate Degradation.6.2.1 Polyphosphate-Glucose Phosphotransferase (EC 2.7.1.63).6.2.2 NAD Kinase (ATP:NAD 2--Phosphotransferase, EC 2.7.1.23).6.2.3 Exopolyphosphatase (Polyphosphate Phosphohydrolase, EC 3.6.1.11).6.2.4 Adenosine-Tetraphosphate Phosphohydrolase (EC 3.6.1.14).6.2.5 Triphosphatase (Tripolyphosphatase, EC 3.6.1.25).6.2.6 Endopolyphosphatase (Polyphosphate Depolymerase, EC 3.6.1.10).6.2.7 PolyP:AMP Phosphotransferase.7 The Functions of Polyphosphates and Polyphosphate-Dependent Enzymes.7.1 Phosphate Reserve.7.1.1 In Prokaryotes.7.1.2 In Eukaryotes.7.2 Energy Source.7.2.1 Polyphosphates in Bioenergetics of Prokaryotes.7.2.2 Polyphosphate in Bioenergetics of Eukaryotes.7.3 Cations Sequestration and Storage.7.3.1 In Prokaryotes.7.3.2 In Eukaryotes.7.4 Participation in Membrane Transport.7.5 Cell Envelope Formation and Function.7.5.1 Polyphosphates in the Cell Envelopes of Prokaryotes.7.5.2 Polyphosphates in the Cell Envelopes of Eukaryotes.7.6 Regulation of Enzyme Activities.7.7 Gene Activity Control, Development and Stress Response.7.7.1 In Prokaryotes.7.7.2 In Lower Eukaryotes.7.8 The Functions of Polyphosphates in Higher Eukaryotes.8 The Peculiarities of Polyphosphate Metabolism in Different Organisms.8.1 Escherichia coli.8.1.1 The Dynamics of Polyphosphates under Culture Growth.8.1.2 The Effects of Pi Limitation and Excess.8.1.3 The Effects of Mutations on Polyphosphate Levels and Polyphosphate-Metabolizing Enzyme Activities.8.1.4 The Effects of Nutrition Deficiency and Environmental Stress.8.2 Pseudomonas aeruginosa.8.3 Acinetobacter.8.4 Aerobacter aerogenes (Klebsiella aerogenes).8.5 Azotobacter.8.6 Cyanobacteria (Blue-Green Algae) and other Photosynthetic Bacteria.8.7 Mycobacteria and Corynebacteria.8.8 Propionibacteria.8.9 Archae.8.10 Yeast.8.10.1 Yeast Cells Possess Different Polyphosphate Fractions.8.10.2 The Dynamics of PolyP Fractions during the Cell Cycle.8.10.3 The Relationship between the Metabolism of Polyphosphates and other Compounds.8.10.4 Polyphosphate Fractions at Growth on a Pi-Sufficient Medium with Glucose.8.10.5 The Effects of Pi Limitation and Excess.8.10.6 The Effects of other Conditions on the Polyphosphate Content in Yeast Cells.8.10.7 The Effects of Inhibitors on the Polyphosphate Content in Yeast Cells.8.10.8 The Effects of Mutations on the Content and Chain Lengths of Polyphosphate in Yeast.8.11 Other Fungi (Mould and Mushrooms).8.12 Algae.8.12.1 Localization and Forms in Cells.8.12.2 The Dynamics of Polyphosphates in the Course of Growth.8.12.3 The Influence of Light and Darkness.8.12.4 The Effects of Pi Limitation and Excess.8.12.5 Changes in Polyphosphate Content under Stress Conditions.8.13 Protozoa.8.14 Higher Plants.8.15 Animals.9 Applied Aspects of Polyphosphate Biochemistry.9.1 Bioremediation of the Environment.9.1.1 Enhanced Biological Phosphate Removal.9.1.2 Removal of Heavy Metals from Waste.9.2 Polyphosphates and Polyphosphate-Metabolizing Enzymes in Assay and Synthesis.9.3 Polyphosphates in Medicine.9.3.1 Antiseptic and Antiviral Agents.9.3.2 Polyphosphate Kinase as a Promising Antimicrobial Target.9.3.3 Polyphosphates as New Biomaterials.9.3.4 Polyphosphates in Bone Therapy and Stomathology.9.4 Polyphosphates in Agriculture.9.5 Polyphosphates in the Food Industry.10 Inorganic Polyphosphates in Chemical and Biological Evolution.10.1 Abiogenic Synthesis of Polyphosphates and Pyrophosphate.10.2 Phosphorus Compounds in Chemical Evolution.10.3 Polyphosphates and Pyrophosphates: Fossil Biochemical Reactions and the Course of Bioenergetic Evolution.10.4 Changes in the Role of Polyphosphates in Organisms at Different Evolutionary Stages.References.Index of Generic Names.Subject Index.

566 citations


Journal ArticleDOI
TL;DR: In this paper, a qualitative interpretation of the breakdown phenomenon is proposed, which is based upon the concept of structural defects of the type of throughgoing pores, whose development is favored by the electric field.

515 citations


Journal ArticleDOI
TL;DR: The present paper is a summing up of the studies, begun in 1976, that have resulted in the complete study of bacteriorhodopsin, and gives the first indications of how the molecule is packed in the membrane.

418 citations


Journal ArticleDOI
TL;DR: In this paper, the α s 2 corrections to σ tot (e + e − → hadrons) in massless QCD evaluated within the minimal subtraction scheme were presented.

349 citations


Journal ArticleDOI
TL;DR: It is shown that the retrieval ambiguity represents a lesser problem in the two-dimensional case compared to the well-known problem of image reconstruction from its spectrum modulus.

345 citations


Journal ArticleDOI
TL;DR: A new model for DNA folding in the nucleosome is proposed according to which the DNA molecule is kinked each fifth base pair to the side of the minor and major grooves alternatively.
Abstract: Potential energy calculations of the DNA duplex dimeric subunit show that the double helix may be bent in the direction of minor and major grooves much more easily than in other directions. It is found that the total winding angle of DNA decreases upon such bending. A new model for DNA folding in the nucleosome is proposed on the basis of these findings according to which the DNA molecule is kinked each fifth base pair to the side of the minor and major grooves alternatively. The model explains the known contradiction between a C-like circular dichroism for the nucleosomal DNA and the nuclease digestion data, which testify to the B-form of DNA.

194 citations


Journal ArticleDOI
TL;DR: A two-formant synthetic vowel with closely spaced formants (F1 and F2 being fixed) can be made perceptually similar to a single- formant stimulus with F ★ = (F 1 + F 2 ) 2 by adjusting the amplitude ratio of the formants.

Book ChapterDOI
TL;DR: This chapter discusses the genetic control of meiosis, which presents a seemingly paradoxical situation in which universality and uniqueness are harmoniously combined.
Abstract: Publisher Summary This chapter discusses the genetic control of meiosis. Meiosis presents a seemingly paradoxical situation in which universality and uniqueness are harmoniously combined. All organisms, irrespective of their evolved complexity, meiotically reduce the chromosome number on beginning sexual reproduction. Genetic recombination and the associated cytological phenomena—chromosome pairing and formation of the synaptonemal complex (sc) and chiasmata—all occur in meiotically dividing cells. The majority of genes do not turn the meiotic process entirely off; they rather interfere with its distinct steps. These comparisons of meiotic mutants make it possible to distinguish between primary and secondary abnormalities caused by mutations in different genes. Other meiotic mutants can serve as points plotted on a genetic flowchart depicting the sequential switching on of meiotic genes. Chromosome behavior appears to be controlled at two levels. There seems to exist a group of genes controlling the behavior of all the chromosomes in the nucleus and another group that controls the behavior of single chromosomes.


Journal ArticleDOI
TL;DR: In this paper, it is assumed that the BLM breakdown in external electrical field is related to the occurrence of supercritical defects, such an event is viewed at as a result of diffusion-like variation of the defect radius.

Journal ArticleDOI
TL;DR: In this article, the performances of diamond nuclear radiation detectors have been investigated using alpha and beta particles, and an energy for electron-hole pair creation of 13.19 eV has been determined for alpha particles in the 5-6 MeV energy range.

Journal ArticleDOI
TL;DR: The results agree with the idea that the influence exerted by proline and hydroxyproline on the stabilization of the triple helix of collagen is different.
Abstract: A new analysis has been made on studies of the influence of imino acid content on the changes of collagen thermal stability (tm). It is shown that, for the interstitial vertebrate collagens, there is a strict regularity in the changes of tm depending on hydroxyproline content. No correlation is observed between tm and proline content. Also, no correlation between tm and hydroxyproline content is observed for invertebrate and basement membrane collagens. On the basis of the reported data, the dependence of tm on hydroxyproline content is considered to be not a correlation between tm and the total content of hydroxyproline, but only as the correlation between tm and the content of hydroxyproline occurring at the third position in the sequence (Gly-R2-R3)n. The results agree with the idea that the influence exerted by proline and hydroxyproline on the stabilization of the triple helix of collagen is different.

Journal ArticleDOI
TL;DR: In this article, the first experimental evidence has been obtained for steering of charged particle trajectories by a bent silicon crystal, which corresponds to a bending radius of 38 cm and the effective transverse component of the electric field acting on the proton beam is equal to 240 MV/cm.

Journal ArticleDOI
TL;DR: A review of lattice structures, electrical and optical properties of boron and its compounds can be found in this article, with a focus on the properties of rare-earth compounds.
Abstract: A review is given on investigations of lattice structures, electrical and optical properties of boron and boron compounds (crystalline boron modifications and their compound analogs, rare-earth compounds, Asup(III)Bsup(V)compounds).

Journal ArticleDOI
TL;DR: In this article, a general theory of microwave devices based on the ultrarelativistic Doppler up-conversion of electron oscillation frequency is developed and a universal relation between the frequency conversion factor and the efficiency of the laser is derived.

Journal ArticleDOI
TL;DR: In this article, the absorption spectrum of the OHO fragment is separated from the spectra of the solutions investigated, and a theoretical model is suggested which explains the origin of the continuum by a strong proton-phonon coupling.

Journal ArticleDOI
TL;DR: In this paper, the ESCA spectra of a series of NiO/SiO2 and NiO-Al2O3/Si2O2 catalysts are reported, together with those of some reference compounds.

Journal ArticleDOI
26 Jul 1979-Nature
TL;DR: The distribution of closed unknotted polymer chains over the writhing number is calculated by the Monte-Carlo method and the balance which arises from fluctuations in DNA twisting makes it possible to estimate the torsional stiffness of the double helix.
Abstract: The distribution of closed unknotted polymer chains over the writhing number is calculated by the Monte-Carlo method For circular duplex DNA the variance of the distribution equals approximately half the observed variance of equilibrium distribution over the linking number The balance which arises from fluctuations in DNA twisting makes it possible to estimate the torsional stiffness of the double helix

Journal ArticleDOI
TL;DR: In this article, the crystal structure of tetrameric Al(OPr-iso) 3 has been determined by single crystal X-ray diffraction and a strucrural model of the polymerization equilibrium is suggested.

Journal ArticleDOI
TL;DR: In this article, the basic role of the transition metal-carbon bond in the catalytic polymerization of olefins was formulated in the early stages of the study of Ziegler-Natta catalysts.
Abstract: The concept of the basic role of the transition metal-carbon bond in the catalytic polymerization of olefins was formulated in the early stages of the study of Ziegler-Natta catalysts (see Ref. 1). In this connection, attempts to use the individual organometallic transition metal compounds as catalysts for olefin polymerization have been made regularly when such compounds were synthesized[2–10]. Polymerization of ethylene in the presence of organometallic compounds containing [sbnd]CH3[2, 3], [sbnd]C6H5[7], [sbnd]CH2C6H5[5, 6], [sbnd]C3H5[4, 10], [sbnd]CH2-C(CH3)3[10], and [sbnd]CH2-Si(CH3)3[10] as organic ligands have been reported. In some cases such compounds were considered to be “models of the active centers.” However, considering the experimental results from this point of view led to a discrepancy with the following observations:

Journal ArticleDOI
TL;DR: The optical anisotropy induced in films of some chalcogenide vitreous semiconductors (ChVS) by linearly polarized light is studied in this article, where spectral responses of the photoinduced dichroism are compared with the transmission spectra of the illuminated films.
Abstract: The optical anisotropy induced in films of some chalcogenide vitreous semiconductors (ChVS) by linearly polarized light is studied. The spectral responses of the photoinduced dichroism are compared with the transmission spectra of the illuminated films. The phenomenon of photoinduced anisotropy is associated with the existence of highly-dispersed, optically anisotropic structure elements in the isotropic (on the average) ChVS films. Es wird mittels polarisiertem Licht die optische Anisotropie untersucht, die in Schichten von einigen glasartigen Chalkogenidhalbleitern (ChVS) induziert wird. Die spektrale Response des photoinduzierten Dichroismus wird mit den Transmissionsspektren der belichteten Schichten verglichen. Das Phanomen der photoinduzierten Anisotropie ist mit der Existenz von hochdispersiven, optisch anisotropen Strukturelementen in den (im Mittel) isotropen ChVS-Schichten verknupft.

Journal ArticleDOI
TL;DR: In this paper, the strong interaction coupling constants of the S ∗ and δ mesons with the K K channel were determined to be of the order of [(m K 0 − m K + )/m K − 0 ] 1 2, and not of (mK0 − mK+)/mK 0, as would be expected from simple considerations.

Book ChapterDOI
TL;DR: About 15 years ago, high toxicity and specific biological activity of 1-arylsilatranes were discovered which belonged to an almost unknown class of heterocyclic derivatives of penta-coordinate silicon with general formula.
Abstract: About 15 years ago we discovered high toxicity and specific biological activity of 1-arylsilatranes (1, 2) which, at that time, belonged to an almost unknown class of heterocyclic derivatives of penta-coordinate silicon with general formula (Fig. 1). Open image in new window


Journal ArticleDOI
TL;DR: The thermodynamic analysis of microcalorimetric and hydrogen exchange data on the stability and mobility of collagen structures from different species with different physiological temperatures has shown that not only the thermostability but the enthalpy and entropy of disruption of the native collagen structure are increasing functions of the total prolyl and hydroxyprolyl content as mentioned in this paper.

Journal ArticleDOI
TL;DR: The conclusion has been drawn that the bulk of attachment sites of DNP fibrils to axial chromosomal structures remains unchanged during the cell cycle.
Abstract: The fragments of DNA attached to protein skeleton of interphase nuclei or metaphase chromosomes were obtained Both the method involving restriction endonuclease treatment/1,2/and a novel procedure based on mild staphylococcal nuclease digestion were used In the latter case, DNA fragments remaining bound to nuclei or chromosomes are not enriched in satellite but only in abundant middle repetitive DNA The shorter the fragments of attached DNA, the higher the content of middle repetitive DNA in the fraction It has a slightly higher density in a CsCl gradient comparing to the main DNA The yield of attached DNA, its distribution in a CsCl density gradient, and its renaturation properties are essentially the same for interphase and metaphase chromosomes The average size of DNA loops was found to be equal to approximately 60 kb for both metaphase chromosomes and interphase nuclei The conclusion has been drawn that the bulk of attachment sites of DNP fibrils to axial chromosomal structures remains unchanged during the cell cycle