scholarly journals Effects of Ionic Strength, Temperature, and Urea on Behaviors of Methyl Orange-Dodecyltrimethylammonium Complex.

1993 ◽  
Vol 49 (4) ◽  
pp. 176-181 ◽  
Author(s):  
Masaru Mitsuishi ◽  
Daisuke Yoshida ◽  
Syouichi Urata ◽  
Kunihiro Hamada ◽  
Tsutomu Ishiwatari
Keyword(s):  
1954 ◽  
Vol 32 (1) ◽  
pp. 109-118
Author(s):  
J. Ross Colvin

Adsorption isotherms for methyl orange on lysozyme at ionic strengths varying from 0.001 to 0.05, pH 5.5, are sigmoid. Increasing ionic strength shifts the inflection point of such isotherms to higher free anion concentrations. Binding of one methyl orange anion to a lysozyme molecule in 0.05 M acetate, pH 5.5, facilitates adsorption of nine others, with subsequent precipitation of the protein. This co-operative behavior is interpreted on the basis of a previously described theory of interacting hydration effects. The possible biological implications for similar systems are indicated.


2018 ◽  
Vol 5 (1) ◽  
pp. 38-43
Author(s):  
Haider Shanshool Mohammed

"In the current study, the effect of the immobilization on electrostatic potential, pH and the absorbance of aqueous solutions of methyl orange that was immobilized on a modified chitosan polymer by glass wool were studied. It was found that the values of these parameters of the supported methyl orange are increased compared to unsupported samples. Furthermore, the electrostatic potential of the supported methyl orange is investigated in the presence of an aqueous solutions of NaCl, where showed the value of the electrostatic potential is raised With increasing ionic strength of the sodium chloride solution and a decrease in the value of pKa to the methyl orange dye after immobilization while the results are inversely before immobilization methyl orange on a modified chitosan polymer by glass wool.


1964 ◽  
Vol 10 (4) ◽  
pp. 309-320 ◽  
Author(s):  
Jesse F Goodwin

Abstract Values for serum albumin obtained by the methyl orange and 2-(4’-hydroxyazobenzene) benzoic acid (HABA) dye-absorption methods have been compared with values obtained by Spinco Procedure B paper-electrophoresis system. A good correlation of albumin values has been found by the three methods in serums with albumin/globulin ratios ranging from 0.19 to 3.00. Modifications of the dye-absorption procedures are presented which permit use of reagents ordinarily employed for automatic analyses on small numbers of specimens. A decrease in ionic strength of the methyl orange buffer tends to increase the sensitivity of this procedure. Temperature affects the HABA dye/albumin reaction. Bilirubin, free hemoglobin, and lipid interfere with both dye procedures. Means for eliminating most of these interferences have been presented. The methyl orange procedure appears to be superior to the 2-(4 -hydroxyazobenzene) benzoic acid method for estimating albumin in icteric serum and serum containing macroglobulins. Albumin values of serum containing abnormal proteins were compared with values obtained by paper electrophoresis and both dye procedures. Estimation of albumin by the two dye procedures appears to be simple, precise, and fairly specific.


1954 ◽  
Vol 32 (2) ◽  
pp. 109-118 ◽  
Author(s):  
J. Ross Colvin

Adsorption isotherms for methyl orange on lysozyme at ionic strengths varying from 0.001 to 0.05, pH 5.5, are sigmoid. Increasing ionic strength shifts the inflection point of such isotherms to higher free anion concentrations. Binding of one methyl orange anion to a lysozyme molecule in 0.05 M acetate, pH 5.5, facilitates adsorption of nine others, with subsequent precipitation of the protein. This co-operative behavior is interpreted on the basis of a previously described theory of interacting hydration effects. The possible biological implications for similar systems are indicated.


Author(s):  
F. Thoma ◽  
TH. Koller

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.


Author(s):  
J.S. Wall ◽  
V. Maridiyan ◽  
S. Tumminia ◽  
J. Hairifeld ◽  
M. Boublik

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).


Author(s):  
S. Trachtenberg ◽  
D. J. DeRosier

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.


1988 ◽  
Vol 85 ◽  
pp. 523-527
Author(s):  
M.M. Zuleika ◽  
Palhares SILVA ◽  
Ernesto Rafael GONZALEZ ◽  
Luis Alberto AVACA ◽  
Artur de Jesus MOTHEO

1987 ◽  
Vol 58 (04) ◽  
pp. 1064-1067 ◽  
Author(s):  
K Kodama ◽  
B Pasche ◽  
P Olsson ◽  
J Swedenborg ◽  
L Adolfsson ◽  
...  

SummaryThe mode of F Xa inhibition was investigated on a thromboresistant surface with end-point attached partially depoly-merized heparin of an approximate molecular weight of 8000. Affinity chromatography revealed that one fourth of the heparin used in surface coating had high affinity for antithrombin III (AT). The heparin surface adsorbed AT from both human plasma and solutions of purified AT. By increasing the ionic strength in the AT solution the existence of high and low affinity sites could be shown. The uptake of AT was measured and the density of available high and low affinity sites was found to be in the range of 5 HTid 11 pic.omoles/cmf, respectively Thus the estimated density of biologically active high and low ailmity heparm respectively would be 40 and 90 ng/cm2 The heparin coating did not take up or exert F Xa inhibition by itself. With AT adsorbed on both high and low affinity heparin the surface had the capacity to inhibit several consecutive aliquots of F Xa exposed to the surface. When mainly high affinity sites were saturated with AT the inhibition capacity was considerably lower. Tt was demonstrated that the density of AT on both high and low affinity heparin determines the F Xa inhibition capacity whereas the amount of AT on high affinity sites limits the rate of the reaction. This implies that during the inhibition of F Xa there is a continuous surface-diffusion of AT from sites of a lower class to the high affinity sites where the F Xa/AT complex is formed and leaves the surface. The ability of the immobilized heparin to catalyze inhibition of F Xa is likely to be an important component for the thromboresistant properties of a heparin coating with non-compromized AT binding sequences.


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