370. The solvent properties of aqueous solutions of paraffin-chain salts. Part I. The solubility of trans-azobenzene in solutions of cetylpyridinium salts

1938 ◽  
pp. 1968 ◽  
Author(s):  
G. Spencer Hartley
Keyword(s):  
Aqueous Solutions ◽  
Solvent Properties ◽  
Trans Azobenzene

DNA KNOT FORMATION IN AQUEOUS SOLUTIONS

1994 ◽  
Vol 03 (03) ◽  
pp. 287-298 ◽  
Author(s):  
STANLEY Y. SHAW ◽  
JAMES C. WANG
Keyword(s):  
Aqueous Solutions ◽  
Experimental Test ◽  
Attractive Potential ◽  
Sodium Ions ◽  
Magnesium Ions ◽  
Close Apposition ◽  
Closed Chain ◽  
Solvent Properties

The knotting probability of a closed chain has been calculated as a function of chain dimensions and solvent properties in a number of studies. We have measured the probability of DNA knot formation upon random cyclization of linear DNA in vitro to provide an experimental test of the various theoretical treatments of the problem; parameters of these models, such as the effective chain diameter of DNA, were calculated in different concentrations of counterions. Our results in the presence of sodium ions agree well with theoretical treatments of DNA as a polyelectrolyte; knotting data in the presence of divalent magnesium ions indicate that moderate concentrations of magnesium ions can induce an attractive potential between DNA segments, resulting in negative values of the calculated effective DNA helix diameter. We discuss structures in which the divalent magnesium counterion facilitates the close apposition of two DNA segments, and review the effect of chemical- and protein-mediated crosslinks between DNA segments on DNA knot formation. Finally, we consider DNA knot formation in vivo.

Solvent properties of glass melts: resemblance to aqueous solutions

2002 ◽  
Vol 5 (11) ◽  
pp. 797-804 ◽  
Author(s):  
John A Duffy ◽  
Malcolm D Ingram
Keyword(s):  
Aqueous Solutions ◽  
Glass Melts ◽  
Solvent Properties

Co-extraction of phosphoric and tetrachloroferric acids

1968 ◽  
Vol 46 (4) ◽  
pp. 662-663 ◽  
Author(s):  
Robert H. McCorkell ◽  
John W. Irvine Jr.
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Organic Solvents ◽  
Strong Acid ◽  
Ionic Species ◽  
The Other ◽  
Solvent Properties

The presence of an extracting strong acid greatly enhances the extraction of phosphoric acid from aqueous solutions into organic solvents, but no type of compound forms between the phosphoric acid and the other extracted species. Only the alteration of the solvent properties when an ionic species and water are added to it can account for the increase in [Formula: see text]

scholarly journals Solvent Properties of Water in Aqueous Solutions of Elastin-Like Polypeptide

2015 ◽  
Vol 16 (12) ◽  
pp. 13528-13547 ◽  
Author(s):  
Luisa Ferreira ◽  
James Cole ◽  
Christian Reichardt ◽  
Nolan Holland ◽  
Vladimir Uversky ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Solvent Properties

Analyzing the effects of protecting osmolytes on solute–water interactions by solvatochromic comparison method: I. Small organic compounds

RSC Advances ◽  
2015 ◽  
Vol 5 (74) ◽  
pp. 59812-59822 ◽  
Author(s):  
Luisa A. Ferreira ◽  
Pedro P. Madeira ◽  
Vladimir N. Uversky ◽  
Boris Y. Zaslavsky
Keyword(s):  
Aqueous Solutions ◽  
Organic Compounds ◽  
Comparison Method ◽  
Solute Water ◽  
Solvent Properties

Solvent properties of water in aqueous solutions of osmolytes (sorbitol, sucrose, trehalose, and trimethylamine N-oxide (TMAO)) were studied at different concentrations using the solvatochromic comparison method.

scholarly journals The unfolding of iRFP713 in a crowded milieu

2018 ◽  
Author(s):  
Olesya V. Stepanenko ◽  
Olga V Stepanenko ◽  
Irina M. Kuznetsova ◽  
Konstantin K Turoverov
Keyword(s):  
Aqueous Solutions ◽  
Molecular Mass ◽  
Intermediate State ◽  
Excluded Volume ◽  
Concentrated Solutions ◽  
Dextran 40 ◽  
Dextran 70 ◽  
Peg 8000 ◽  
Solvent Properties

The exploring of biological processes in vitro under conditions of macromolecular crowding is a way to achieve an understanding of how these processes occur in vivo. In this work, we study the unfolding of the fluorescent probe iRFP713 in crowded environment in vitro. Previously, we showed that the unfolding of the dimeric iRFP713 is accompanied by the formation of a compact monomer and an intermediate state of the protein. In the intermediate state, the macromolecules of iRFP713 have hydrophobic clusters exposed to the surface of the protein and are prone to aggregation. Concentrated solutions of polyethylene glycol (PEG-8000), Dextran-40 and Dextran-70 with a molecular mass of 8000, 40000 and 70000 Da, respectively, were used to model the conditions for macromolecular crowding. A limited available space provided by all the crowding agents used favors to the enhanced aggregation of iRFP713 in the intermediate state at the concentration of guanidine hydrochloride (GdnHCl), at which the charge of protein surface is neutralized by the guanidine cations. This is in line with the theory of the excluded volume. In concentrated solutions of the crowding agents (240–300 mg/ml), the stabilization of the structure of iRFP713 in the intermediate state is observed. PEG-8000 also enhances the stability of iRFP713 in the monomeric compact state, whereas in concentrated solutions of Dextran-40 and Dextran-70 the resistance of the protein in the monomeric state against GdnHCl-induced unfolding decreases. The obtained data argues for the excluded volume effect being not the only factor that contributes the behavior of biological molecules in a crowded milieu. Crowding agents do not affect the structure of the native dimer of iRFP713, which excludes the direct interactions between the target protein and the crowding agents. PEGs of different molecular mass and Dextran-40/Dextran-70 are known to influence the solvent properties of water. The solvent dipolarity/polarizability and basicity/acidity in aqueous solutions of these crowding agents vary in different ways. The change of the solvent properties in aqueous solutions of crowding agents might impact the functioning of a target protein.

scholarly journals The unfolding of iRFP713 in a crowded milieu

2018 ◽  
Author(s):  
Olesya V. Stepanenko ◽  
Olga V Stepanenko ◽  
Irina M. Kuznetsova ◽  
Konstantin K Turoverov
Keyword(s):  
Aqueous Solutions ◽  
Molecular Mass ◽  
Intermediate State ◽  
Excluded Volume ◽  
Concentrated Solutions ◽  
Dextran 40 ◽  
Dextran 70 ◽  
Peg 8000 ◽  
Solvent Properties

The exploring of biological processes in vitro under conditions of macromolecular crowding is a way to achieve an understanding of how these processes occur in vivo. In this work, we study the unfolding of the fluorescent probe iRFP713 in crowded environment in vitro. Previously, we showed that the unfolding of the dimeric iRFP713 is accompanied by the formation of a compact monomer and an intermediate state of the protein. In the intermediate state, the macromolecules of iRFP713 have hydrophobic clusters exposed to the surface of the protein and are prone to aggregation. Concentrated solutions of polyethylene glycol (PEG-8000), Dextran-40 and Dextran-70 with a molecular mass of 8000, 40000 and 70000 Da, respectively, were used to model the conditions for macromolecular crowding. A limited available space provided by all the crowding agents used favors to the enhanced aggregation of iRFP713 in the intermediate state at the concentration of guanidine hydrochloride (GdnHCl), at which the charge of protein surface is neutralized by the guanidine cations. This is in line with the theory of the excluded volume. In concentrated solutions of the crowding agents (240–300 mg/ml), the stabilization of the structure of iRFP713 in the intermediate state is observed. PEG-8000 also enhances the stability of iRFP713 in the monomeric compact state, whereas in concentrated solutions of Dextran-40 and Dextran-70 the resistance of the protein in the monomeric state against GdnHCl-induced unfolding decreases. The obtained data argues for the excluded volume effect being not the only factor that contributes the behavior of biological molecules in a crowded milieu. Crowding agents do not affect the structure of the native dimer of iRFP713, which excludes the direct interactions between the target protein and the crowding agents. PEGs of different molecular mass and Dextran-40/Dextran-70 are known to influence the solvent properties of water. The solvent dipolarity/polarizability and basicity/acidity in aqueous solutions of these crowding agents vary in different ways. The change of the solvent properties in aqueous solutions of crowding agents might impact the functioning of a target protein.

scholarly journals The unfolding of iRFP713 in a crowded milieu

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6707
Author(s):  
Olesya V. Stepanenko ◽  
Olga V. Stepanenko ◽  
Irina M. Kuznetsova ◽  
Konstantin K. Turoverov
Keyword(s):  
Aqueous Solutions ◽  
Molecular Mass ◽  
Intermediate State ◽  
Excluded Volume ◽  
Concentrated Solutions ◽  
Dextran 40 ◽  
Dextran 70 ◽  
Peg 8000 ◽  
Solvent Properties

The exploring of biological processes in vitro under conditions of macromolecular crowding is a way to achieve an understanding of how these processes occur in vivo. In this work, we study the unfolding of the fluorescent probe iRFP713 in crowded environment in vitro. Previously, we showed that the unfolding of the dimeric iRFP713 is accompanied by the formation of a compact monomer and an intermediate state of the protein. In the intermediate state, the macromolecules of iRFP713 have hydrophobic clusters exposed to the surface of the protein and are prone to aggregation. Concentrated solutions of polyethylene glycol (PEG-8000), Dextran-40 and Dextran-70 with a molecular mass of 8000, 40000 and 70000 Da, respectively, were used to model the conditions for macromolecular crowding. A limited available space provided by all the crowding agents used favors to the enhanced aggregation of iRFP713 in the intermediate state at the concentration of guanidine hydrochloride (GdnHCl), at which the charge of protein surface is neutralized by the guanidine cations. This is in line with the theory of the excluded volume. In concentrated solutions of the crowding agents (240–300 mg/ml), the stabilization of the structure of iRFP713 in the intermediate state is observed. PEG-8000 also enhances the stability of iRFP713 in the monomeric compact state, whereas in concentrated solutions of Dextran-40 and Dextran-70 the resistance of the protein in the monomeric state against GdnHCl-induced unfolding decreases. The obtained data argues for the excluded volume effect being not the only factor that contributes the behavior of biological molecules in a crowded milieu. Crowding agents do not affect the structure of the native dimer of iRFP713, which excludes the direct interactions between the target protein and the crowding agents. PEGs of different molecular mass and Dextran-40/Dextran-70 are known to influence the solvent properties of water. The solvent dipolarity/polarizability and basicity/acidity in aqueous solutions of these crowding agents vary in different ways. The change of the solvent properties in aqueous solutions of crowding agents might impact the functioning of a target protein.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

Sign in / Sign up

Export Citation Format

Share Document