scholarly journals Differing accessibility in chromatin of the antigenic sites of regions 1-58 and 63-125 of histone H2B.

1981 ◽  
Vol 91 (1) ◽  
pp. 135-141 ◽  
Author(s):  
D di Padua Mathieu ◽  
C V Mura ◽  
L L Frado ◽  
C L Woodcock ◽  
B D Stollar
Keyword(s):  
Ionic Strength ◽  
Staining Intensity ◽  
Histone H2b ◽  
Antigenic Sites ◽  
Liver Nuclei ◽  
Low Ionic Strength

Experiments with antibodies induced by separated fragments 1-58 and 63-125 of H2B histone indicated that the 1-58 portion of the molecule is much more accessible in chromatin than is the 63-125 region. In immunoabsorption and immunoelectron microscopic assays with bovine and chicken chromatins, anti-1-58 antibodies reacted with sheared or unsheared chromatin both at low ionic strength (1 mM Tris-HCl) and in 0.14 M NaCl. Anti-63-125 antibodies were bound only weakly by chromatin at low ionic strength and not at all in 0.14 M NaCl. Antibodies to whole H2B showed intermediate reactivity with chromatin in both assays. In tests of immunofluorescence with unfixed calf liver nuclei in suspension, anti-1-58 caused nucleolar as well as nucleoplasmic fluorescence, whereas anti-63-125 did not lead to detectable fluorescence; anti-H2B showed intermediate staining intensity. In control experiments, anti-H1 antibody was bound by chromatin at low ionic strength but not in 0.14 M NaCl; anti-H3 antibody was bound poorly under either condition.

scholarly journals Experimental conditions affecting ribonucleic acid polymerase in isolated rat liver nuclei. Effect of nucleoside triphosphate concentration, temperature, ammonium sulphate and heparin

1969 ◽  
Vol 112 (5) ◽  
pp. 721-727 ◽  
Author(s):  
F. Novello ◽  
F. Stirpe
Keyword(s):  
Ionic Strength ◽  
Rna Polymerase ◽  
Ammonium Sulphate ◽  
Rat Liver ◽  
High Ionic Strength ◽  
Isolated Rat Liver ◽  
Rat Liver Nuclei ◽  
Liver Nuclei ◽  
Low Ionic Strength ◽  
Isolated Rat

1. The conditions affecting the activity of RNA polymerase in isolated rat liver nuclei were studied with Mg2+ or Mn2+ as activating ions. 2. The enzyme assayed with Mg2+ and at low ionic strength is saturated by a lower concentration of nucleotide substrates than if assayed with Mn2+ at low ionic strength or with either ion at high ionic strength. 3. At low and at high ionic strength the incorporation of AMP is affected in a similar way by variations in the temperature of incubation. Preincubation at 37° impairs the AMP incorporation. 4. Heparin stimulates the RNA polymerase activity in the presence of Mn2+. 5. Both ammonium sulphate and heparin ‘restart’ the reaction if added after 15min., the effect being more marked with ammonium sulphate than with heparin, and also more marked in the presence of Mn2+ than of Mg2+. 6. α-Amanitin abolishes the effect of ammonium sulphate and of heparin.

Rat Liver Nuclear Protein Kinases

1975 ◽  
Vol 53 (3) ◽  
pp. 354-363 ◽  
Author(s):  
P. R. Desjardins ◽  
C. C. Liew ◽  
A. G. Gornall
Keyword(s):  
Ionic Strength ◽  
Cyclic Amp ◽  
Dehydrogenase Activity ◽  
Kinase Activity ◽  
Nuclear Material ◽  
Casein Kinase ◽  
Casein Kinases ◽  
Liver Nuclei ◽  
Histone Kinase ◽  
Low Ionic Strength

We have shown that nuclei isolated by two methods contain grossly different amounts of cyclic AMP-dependent histone kinase activity. Repeated washing of the isolated nuclei with a low ionic strength buffer removed the majority of the cyclic AMP-dependent histone kinase and cyclic AMP binding activity. Nuclear cyclic AMP-dependent histone kinase activity accounted for only 0.42% of the total cytoplasmic enzyme activity. Similarly, the lactate dehydrogenase activity associated with liver nuclei represented only 0.07% of the total cytoplasmic activity. The isolated liver nuclei contained only 0.27% of the total homogenate glutamate dehydrogenase activity and 1.7% of the total homogenate glucose-6-phosphatase activity. The cyclic AMP-dependent histone kinase behaves as a cytoplasmic rather than a nuclear enzyme. We have also shown that using crude extracts, one can achieve separation of the two nuclear casein kinases, NI and NII, on sucrose density gradients in the presence of 0.5 M NaCl. Nuclear casein kinases NI and NII had sedimentation coefficients of 3.0 and 5.3 S, respectively, in the presence of 0.5 M NaCl. Under conditions of low ionic strength, all of the casein kinase activity in the crude nuclear extract sedimented as one peak with a sedimentation coefficient of 7.3 S. The aggregation–disaggregation which occurred in the crude extract was reversible and was mainly due to the aggregative and disaggregative properties of casein kinase NII The two nuclear casein kinases have different affinities for chromatin. When nuclei were disrupted in a hypotonic solution and extracted with a buffer containing 0.14 M NaCl, casein kinase NII could be completely extracted from the viscous nuclear material. Although a significant amount of casein kinase NI was extracted by the buffer containing 0.14 M NaCl, re-extraction of the nuclear material with a buffer containing 0.5 M NaCl yielded substantial amounts of casein kinase NI, and a final extraction with a buffer containing 1.0 M NaCl yielded measurable amounts of casein kinase NI. No casein kinase NII activity could be detected in the 0.5 M and 1.0 M NaCl extracts.

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.

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.

scholarly journals Crystallization of tuna ferricytochrome c at low ionic strength.

1990 ◽  
Vol 265 (8) ◽  
pp. 4177-4180
Author(s):  
M H Walter ◽  
E M Westbrook ◽  
S Tykodi ◽  
A M Uhm ◽  
E Margoliash
Keyword(s):  
Ionic Strength ◽  
Ferricytochrome C ◽  
Low Ionic Strength

scholarly journals Reaction of Myosin with 1-Fluoro-2,4-dinitrobenzene at Low Ionic Strength

1969 ◽  
Vol 244 (3) ◽  
pp. 648-657 ◽  
Author(s):  
M Bárány ◽  
G Bailin ◽  
K Bárány
Keyword(s):  
Ionic Strength ◽  
Low Ionic Strength

scholarly journals Measuring pH in low ionic strength glacial meltwaters using ion selective field effect transistor (ISFET) technology

2021 ◽  
Author(s):  
Elizabeth A. Bagshaw ◽  
Jemma L. Wadham ◽  
Martyn Tranter ◽  
Alexander D. Beaton ◽  
Jon R. Hawkings ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Effect Transistor ◽  
Low Ionic Strength ◽  
Measuring Ph
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