Presence Of TX-100 Research Articles

Reduction of soluble colloidal MnO2 by DL-malic acid in the absence and presence of nonionic TritonX-100

Kinetics of oxidation of DL-malic acid by water soluble colloidal MnO2 (prepared from potassium permanganate and sodium thiosulfate solutions) have been studied spectrophotometrically in the absence and presence of nonionic Triton X-100 surfactant. The reaction is autocatalytic and manganese(II) (reduction product of the colloidal MnO2) may be the autocatalyst. The order of the reaction is first in colloidal [MnO2] as well as in [malic acid] both in the absence and presence of the surfactant. The reaction has acid-dependent and acid-independent paths and, in the former case, the order is fractional in [H+]. The effect of externally added manganese(II) is complex. The results show that the rate constant increases as the manganese(II) concentration is increased. It is not possible to predict the exact dependence of the rate constants on manganese(II) concentration, which has a series of reactions with other reactants. In the presence of TX-100, the observed effect on kψ is catalytic up to a certain [TX-100]; thereafter, an inhibitory effect follows. The catalytic effect is explained in terms of the mathematical model proposed by Tuncay et al. (in Colloids Surf A Physicochem Eng Aspects 149:279 3). Activation parameters associated with the observed rate constants (kobs/kψ) have also been evaluated and discussed.

Interaction between sodium polystyrenesulfonate and Triton X-100 in aqueous solution

Abstract The interaction between sodium polystyrenesulfonate (PSS) and Triton X-100 (α-(4-octylpenyl)-poly(oxyethylene), TX-100) has been investigated by viscosity and conductivity measurements. The results show that the reduced viscosity of PSS increases with increasing PSS concentration at low constant TX-100 concentrations (0.006 - 0.029 g/ml). On the other hand, at higher constant TX-100 concentrations, 0.048 and 0.062 g/ml, the reduced viscosity decreases with increasing PSS concentration. The behaviour of conductivity of PSS in pure water is quite different from that in the presence of TX-100.

Effect of surfactants on the oxidation of oxalic acid by soluble colloidal MnO 2

Kinetics of the oxidation of oxalic acid by water-soluble colloidal MnO 2 has been studied spectrophotometrically in the absence and presence of non-ionic octylphenoxypolyethoxyethanol (Triton X-100, TX-100) and anionic sodium dodecyl sulfate (SDS) surfactant micelles. Anionic SDS micelles were found ineffective whereas those of TX-100 increased the rate that reached a plateau at higher [TX-100]. The reaction followed first- and fractional-order kinetics with respect to [MnO 2] and [H +], respectively, both in the absence and presence of TX-100. The activation parameters ( E a, Δ H #, and Δ S #) were evaluated and the effect of added manganese(II) sulphate is also reported in both aqueous and aqueous–micellar media. On the basis of experimental findings, a probable mechanism is proposed. The reaction proceeds through the adsorption of oxalic acid and hydrogen ions on the surface of the colloidal MnO 2. Freundlich isotherm is used to explain the adsorption of oxalic acid on colloidal MnO 2.

Insights into the association of FcgammaRII and TCR with detergent-resistant membrane domains: isolation of the domains in detergent-free density gradients facilitates membrane fragment reconstitution.

Plasma membrane rafts are routinely isolated as detergent-resistant membranes (DRMs) floating in detergent-free density gradients. Here we show that both the presence and exclusion of TX-100 during the density gradient fractionation have profound effects on the location of FcgammaRII and TCR in DRM fractions. The presence of TX-100 during fractionation promoted solubilization of non-cross-linked FcgammaRII when the receptor was insufficiently dissolved upon cell lysis. In the detergent-supplemented gradients, TX-100 micelles floated, further enhancing dissociation of FcgammaRII and TCR from DRMs and promoting a shift of the receptors toward higher-density fractions. Hence, fractionation of cell lysates over the detergent-containing gradients enables isolation of DRMs devoid of weakly associated proteins, like nonactivated FcgammaRII and TCR. On the other hand, in a detergent-free gradient, non-cross-linked FcgammaRII, fully soluble in 0.2% TX-100, was recovered in DRM fractions. Moreover, employment of the TX-100-free gradient for refractionation of intermediate-density fractions, derived from detergent-supplemented gradients and containing FcgammaRII and TCR, resulted in flotation of the receptors to buoyant fractions. An analysis of the TX-100 concentration revealed that after fractionation of 0.2% TX-100 cell lysates in the absence of detergent, the level of TX-100 in DRM fractions was reduced to 0.01%, below the critical micelle concentration. Therefore, fractionation of detergent cell lysates over detergent-free gradients can mimic conditions for a membrane reconstitution, evoking association of a distinct subset of membrane proteins, including FcgammaRII and TCR, with DRMs.

The use of 1-[pyridyl-(2)-azo]-naphthol-(2) in the presence of TX-100 and N, N′-diphenylbenzamidine for the spectrophotometric determination of copper in real samples

A simple and sensitive field detection and spectrophotometric method for determination of copper described herewith is based on the formation of a red coloured species of copper(II) with 1-[pyridyl-(2)-azo]-naphthol-(2) (PAN), TX-100 and N, N′-diphenylbenzamidine (DPBA) at pH range 7.8–9.4. The red coloured Cu(II)-PAN-(TX-100)-DPBA complex in chloroform shows maximum absorbance at 520 nm with molar absorptivity value of 1.14×10 5 l mol −1 cm −1. The detection limit of the method is 2 ng ml −1 organic phase. The system obeys Beer’s law up to 0.6 μg Cu(II) ml −1 in organic solution. Most of the common metal ions generally found associated with copper do not interfere. The repeatability of the method was checked by finding relative standard deviation (RSD) ( n=10) value for solutions each containing 0.2 μg ml −1 of Cu(II) and the RSD value of the method was found to be 1.5%. The validity of the method has been satisfactorily examined for the determination of copper in soil and airborne dust particulate samples.

Methodological considerations for the measurement of protein kinase C translocation in intact smooth muscle

This study investigated several potential artifacts that may influence agonist-induced distribution of protein kinase C (PKC) activity between cytosolic and membrane fractions of intact smooth muscle. Protein kinase C activity in the membrane fraction prepared from rat aorta exposed to phorbol myristate acetate (PMA) was only partially extracted by 0.2% Triton (T)X-100, while 1% TX-100, or repeated 0.2% TX-100 extractions completely extracted PKC activity. Extraction of PKC activity from the membrane fraction with TX-100 concentrations of 0.2% or higher was problematic, however, since TX-100 concentrations as low as 0.04% nearly abolished Ca 2+ + phosphatidylserine + diolein-induced phosphorylation of histone substrate in the PKC assay. Substitution of PMA for diolein, however, restored histone phosphorylation to the level observed in the absence of TX-100. Triton X-100 concentrations as low as 0.025% also abolished Ca 2+-induced histone phosphorylation, while Ca 2+ + phosphatidylserine-induced phosphorylation was little affected. In contrast to our previous demonstration that exposure of rat aorta to phorbol ester increased PKC activity in the membrane fraction in aorta washed in Ca 2+-free solution following phorbol ester exposure (Chuprun et al., Am J Physiol 261:C675–C684, 1991; Bazan et al., Eur J Pharmacol-Molec Pharmacol Section 227:343–348, 1992), PMA decreased PKC activity in the initial 0.2% TX-100 extraction of the membrane fraction in the absence of tissue wash in Ca 2+-free solution following PMA exposure. This study, along with our previous reports, suggest that partial PKC extraction from the membrane, and Ca 2+-dependent homogenization-induced translocation of PKC from the cytosol to the membrane fraction, may complicate measurements of agonist-induced PKC translocation. The reliability of PKC assays in crude fractions may be increased in the presence of TX-100, due to the ability of TX-100 to inhibit Ca 2+-induced phosphorylation, and through the substitution of PMA for diolein, which maximally stimulates PKC in the presence of detergent.

Study of the absorption spectra of the 4f electron transition of the Nd and Er complexes with 2-isobutylformyl-1,3-dione-indane in the presence of TX-100 and its analytical application.

The absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 2-isobutylformyl-1,3-dione-indane and TX-100 have been studied by normal and derivative spectrophotometry. Their molar absorptivities at the maximum absorption bands are about 7.2 (at 571 nm) times greater for neodymium and 13.1 (at 519 nm) times greater for erbium than those in the absence of the complexing agents. Use of second derivative spectra both eliminates the interference from other rare earths and increases the sensitivity from neodymium and erbium. Beer's law is obeyed from 0 approximately 20 microg/ml for neodymium and 0 approximately 25 microg/ml for erbium. The relative standard deviations are 1.2% and 1.6% for 5.0 microg/ml of neodymium and 8.0 microg/ml of erbium, respectively. The detection limits (signal-to-noise ratio=2) are 0.14 microg/ml and 0.20 microg/ml. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.

Simultaneous determination of neodymium, erbium and holmium in rare earth mixtures with 2-phenyltrifluoroacetone and octylphenol poly(ethyleneglycol) ether by third-derivative spectrophotometry

The complexes of the rare earth metals with 2-phenyltrifluoroacetone in the presence of TX-100 are reported. The characteristic absorbances of neodymium, holmium and erbium complexes can be increased by factors of 8.5, 31 and 15 respectively, compared to those of the cholrides. The third-derivative spectra have been used to eliminate the interference of cerium, and the sensitivities are increased again by factors of 7.4, 5.5 and 6.5. A method for the direct determination of neodymium, erbium and holmium in rare earth mixtures is proposed.

Derivative spectrophotometric determination of neodymium in rare earth mixtures using bromopyrogallol red and TX-100

A fourth-derivative spectrophotometric procedure is described for the determination of neodymium in mixed rare earths. It is based on the absorption spectrum of the 4f electron transition of the neodymium complex with bromopyrogallol red (BPR) in the presence of TX-100. The influence of various instrumental parameters and reaction conditions on the colour development of the Nd-BPR-TX-100 complex has been investigated. The detection limit is 0.15 μg/mL and the linear dynamic range extends to 3.6 μg/mL. The relative standard deviation is 1.2% for 1.5 μg/mL (n=7). Satisfactory results were obtained.