BACTERIAL CELL MEMBRANES: I. REAGGREGATION OF MEMBRANE SUBUNITS FROM MICROCOCCUS LYSODEIKTICUS

1967 ◽  
Vol 13 (11) ◽  
pp. 1471-1479 ◽  
Author(s):  
Thomas F. Butler ◽  
Gerald L. Smith ◽  
E. A. Grula
Keyword(s):  
Ionic Strength ◽  
Divalent Cation ◽  
Sodium Lauryl Sulfate ◽  
Small Subunit ◽  
Lauryl Sulfate ◽  
Reducing Conditions ◽  
Micrococcus Lysodeikticus ◽  
Monovalent Salt ◽  
Low Ionic Strength ◽  
Bonding Mode

The membranes from M. lysodeikticus can readily be disaggregated into a very small subunit form with sodium lauryl sulfate. Reaggregation of these subunits into membranous sheets occurs during dialysis in a menstruum of relatively low ionic strength, in the presence of a divalent cation at near neutral pH. Reducing conditions and a monovalent salt need not be present during dialysis. Effect of several compounds on membranes and subunit reaggregation was studied. Reaggregated membrane sheets are very similar chemically and morphologically to whole membranes; however, a difference was noted. The major bonding mode in membranes appears to involve hydrophobic groups.

Quasielastische Lichtstreuung von isoliertem Chromatin / Quasielastic Light Scattering of Isolated Chromatin

1983 ◽  
Vol 38 (1-2) ◽  
pp. 126-134 ◽  
Author(s):  
Bernd Meuel ◽  
Holger Notbohm
Keyword(s):  
Light Scattering ◽  
Ionic Strength ◽  
Structural Changes ◽  
Gel Chromatography ◽  
Quasielastic Light Scattering ◽  
Self Assembling ◽  
X Ray Scattering ◽  
Monovalent Salt ◽  
Quaternary Structures ◽  
Low Ionic Strength

Chromatin undergoes structural changes in dependence on the ionic strength of monovalent cations. At low ionic strength an extended chain of nucleosomes is apparent while with increasing ionic strength more compact structures are formed. Soluble chromatin was prepared from rat liver and fractionated by gel chromatography. Quasielastic light scattering experiments on chromatin were done with monovalent salt concentrations ranging from 3-150 mм. Using this method translational diffusion coefficients have been derived. These appeared to be nearly independent of monovalent salt concentrations, indicating that the hydrodynamic radius of chromatin molecules did not change. On the other hand, sedimentation coefficients were increasing according to an exponential relation. Taken together, both findings reveal a rising of the molar mass with increasing ionic strength. On the contrary, chromatin prepared in physiological salt apparently disintegrates by lowering the ionic strength. Furthermore, it could be demonstrated by earlier small angle X-ray scattering studies that the diameter of the higher order chromatin fiber remained constant at approximately 32 nm even if these structures had been reconstituted from smaller pieces starting at low ionic strength. Thus, isolated chromatin fibers are capable of self-assembling to regular quaternary structures, even if the DNA does not form a continuous strand.

Antibody Solubility Behavior in Monovalent Salt Solutions Reveals Specific Anion Effects at Low Ionic Strength

2012 ◽  
Vol 101 (3) ◽  
pp. 965-977 ◽  
Author(s):  
Le Zhang ◽  
Helming Tan ◽  
R. Matthew Fesinmeyer ◽  
Cynthia Li ◽  
David Catrone ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Salt Solutions ◽  
Solubility Behavior ◽  
Monovalent Salt ◽  
Low Ionic Strength

BACTERIAL CELL MEMBRANES: II. POSSIBLE STRUCTURE OF THE BASAL MEMBRANE CONTINUUM OF MICROCOCCUS LYSODEIKTICUS

1967 ◽  
Vol 13 (11) ◽  
pp. 1499-1507 ◽  
Author(s):  
E. A. Grula ◽  
Thomas F. Butler ◽  
Robert D. King ◽  
Gerald L. Smith
Keyword(s):  
Amino Acids ◽  
Membrane Protein ◽  
Layered Structure ◽  
Sodium Lauryl Sulfate ◽  
Basal Membrane ◽  
Lauryl Sulfate ◽  
Protein Membrane ◽  
Micrococcus Lysodeikticus ◽  
Hydrophobic Amino Acids ◽  
Ethyl Acetate Extracts

Treatment of isolated membranes from M. lysodeikitcus with acetone, ethanol, or methanol, but not ethyl acetate, extracts phospholipids and carotenoids. These extracted membranes are not disaggregated by such treatments and retain a three-layered appearance. The extracted membranes can be completely disaggregated by sodium lauryl sulfate, yielding subunits which are primarily protein (stripped subunits). These stripped subunits reaggregate into membranous sheets that also possess a three-layered structure. Conditions for reaggregation of stripped subunits are the same as for unstripped subunits. Extracted phospholipids and carotenoids from M. lysodeikitcus or phospholipids from Erwinia sp. are incorporated into the membranous sheets formed using the stripped subunits from M. lysodeikticus. The composition of the basal membrane continuum from M. lysodeikticus consists primarily of protein; most phospholipids and carotenoids appear to be present as superstructures on the top and bottom of the protein. Membrane protein is basic and does not appear to contain any cysteine. It is speculated that hydrophobic amino acids may be positioned in clusters on the facing sides of the molecules.

Conformational Transitions in Escherichia coli Ribosomal RNAs as Visualized by Dedicated STEM

1988 ◽  
Vol 46 ◽  
pp. 176-177
Author(s):  
J.S. Wall ◽  
V. Maridiyan ◽  
S. Tumminia ◽  
J. Hairifeld ◽  
M. Boublik
Keyword(s):  
Ionic Strength ◽  
Three Dimensional ◽  
Conformational Transitions ◽  
Dark Field ◽  
Dimensional Structure ◽  
Ribosomal Rnas ◽  
Field Mode ◽  
Freeze Dried ◽  
High Resolution Images ◽  
Low Ionic Strength

The high contrast in the dark-field mode of dedicated STEM, specimen deposition by the wet film technique and low radiation dose (1 e/Å2) at -160°C make it possible to obtain high resolution images of unstained freeze-dried macromolecules with minimal structural distortion. Since the image intensity is directly related to the local projected mass of the specimen it became feasible to determine the molecular mass and mass distribution within individual macromolecules and from these data to calculate the linear density (M/L) and the radii of gyration.2 This parameter (RQ), reflecting the three-dimensional structure of the macromolecular particles in solution, has been applied to monitor the conformational transitions in E. coli 16S and 23S ribosomal RNAs in solutions of various ionic strength.In spite of the differences in mass (550 kD and 1050 kD, respectively), both 16S and 23S RNA appear equally sensitive to changes in buffer conditions. In deionized water or conditions of extremely low ionic strength both appear as filamentous structures (Fig. la and 2a, respectively) possessing a major backbone with protruding branches which are more frequent and more complex in 23S RNA (Fig. 2a).

An Evaluation of a Plasma Fractionation System

1960 ◽  
Vol 4 (01) ◽  
pp. 031-044
Author(s):  
George Y. Shinowara ◽  
E. Mary Ruth
Keyword(s):  
Biological Activity ◽  
Ionic Strength ◽  
Plasma Proteins ◽  
High Concentration ◽  
Significant Evidence ◽  
Native Proteins ◽  
Mobility Data ◽  
Fractionation Procedure ◽  
The Individual ◽  
Low Ionic Strength

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.

ASSESSMENT OF THE TOXICITY AND HAZARD OF SODIUM LAURYL SULFATE AT DIFFERENT EXPOSURE ROUTES

2020 ◽  
pp. 56-59
Author(s):  
M. V. Bidevkina ◽  
M. I. Golubeva ◽  
A. V. Limantsev ◽  
I. N. Razumnaya ◽  
T. N. Potapova ◽  
...  
Keyword(s):  
Sodium Lauryl Sulfate ◽  
Exposure Level ◽  
Hazardous Substance ◽  
Lauryl Sulfate ◽  
Upper Respiratory Tract ◽  
Mucous Membranes ◽  
Chloroprene Rubber ◽  
Upper Respiratory ◽  
Exposure Routes ◽  
Number Of Cells

Sodium lauryl sulfate is the most common surfactant used in the production of detergents, chloroprene rubber, plastics, artificial furs and in pharmaceutical industry. Sodium lauryl sulfate is a moderately hazardous substance when introduced into the stomach (DL50 for white mice and rats is in the range of 2086-2700 mg/kg), has a pronounced local irritant effect on the skin and mucous membranes of the eyes, has a skin-resorptive, sensitizing and pronounced cumulative effects. The threshold for acute inhalation action is set at 15,3 mg/m3 for changes in the function of the nervous system and irritating effects on the mucous membranes of the upper respiratory tract (an increase in the total number of cells in the nasal flushes).Recommended for approval tentative safe exposure level of sodium lauryl sulfate in the air of the working area is 0.2+ mg/m3 (aerosol).

scholarly journals A novel procedure for the rapid purification of plastocyanin from pea (Pisum sativum) leaves

1981 ◽  
Vol 193 (1) ◽  
pp. 375-378 ◽  
Author(s):  
A R Ashton ◽  
L E Anderson
Keyword(s):  
Ionic Strength ◽  
Pisum Sativum ◽  
Deae Cellulose ◽  
High Concentrations ◽  
Rapid Purification ◽  
Low Ionic Strength

Plastocyanin is soluble at high concentrations (greater than 3 M) of (NH4)2SO4 but under these conditions will adsorb tightly to unsubstituted Sepharose beads. This observation was utilized to purify plastocyanin from pea (Pisum sativum) in two chromatographic steps. Sepharose-bound plastocyanin was eluted with low-ionic-strength buffer and subsequently purified to homogeneity by DEAE-cellulose chromatography.

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