Increasing Concentrations Of Triton X-100 Research Articles

The effects of surfactants on plunging breakers

The effects of surfactants on a mechanically generated plunging breaker are studied experimentally in a laboratory wave tank. Waves are generated using a dispersively focused wave packet with a characteristic wavelength of $\lambda _0 = 1.18$ m. Experiments are performed with two sets of surfactant solutions. In the first set, increasing amounts of the soluble surfactant Triton X-100 are mixed into the tank water, while in the second set filtered tap water is left undisturbed in the tank for wait times ranging from 15 min to 21 h. Increasing Triton X-100 concentrations and longer wait times lead to surfactant-induced changes in the dynamic properties of the free surface in the tank. It is found that low surface concentrations of surfactants can dramatically change the wave breaking process by changing the shape of the jet and breaking up the entrained air cavity at the time of jet impact. Direct numerical simulations (DNS) of plunging breakers with constant surface tension are used to show that there is significant compression of the free surface near the plunging jet tip and dilatation elsewhere. To explore the effect of this compression/dilatation, the surface tension isotherm is measured in all experimental cases. The effects of surfactants on the plunging jet are shown to be primarily controlled by the surface tension gradient ( $\Delta \mathcal {E}$ ) while the ambient surface tension of the undisturbed wave tank ( $\sigma _0$ ) plays a secondary role.

Effect of Triton X-100 on the wheat and lettuce growth and contaminant absorption

This study was set to study the effects of surfactants on crops using Triton X-100, one of widely used surfactants for various purposes including agricultural uses, as a target surfactant. The effects of Triton X-100 on the growth of wheat and lettuce were studied and the germination and shoot growth of wheat were not significantly affected by Triton X-100. With lettuce, the increasing Triton X-100 concentrations tend to negatively affect the growth, possibly due to the absorption of Triton X-100 by lettuce. The average lettuce fresh mass was reduced by 31% when Triton X-100 concentration increased from 0 to 240 mg L−1. This may mean that chemicals dissolved or mobilized by Triton X-100 can be absorbed by lettuce. The Cd mobilization was facilitated with Triton X-100, and the absorption of procymidone in soil by lettuce was greater when Triton X-100 was applied (i.e., 0.18 mg kg−1) than when water was applied (i.e., 0.15 mg kg−1), although they were statistically not different (p-value > 0.05). The average lettuce masses in the presence of residual procymidone in soil and Triton X-100 (16 g) were lower than that of the control soils (20 g), although they were statistically not different (p-value > 0.05). The results suggest that surfactants contained in pesticide formulations can potentially affect crop growth and absorption of other contaminants. Therefore, the residual surfactants and active ingredients in pesticide formulations need to be properly managed to protect the environment and to produce crops free of contaminants.

Extraction and separation of tungsten (VI) from aqueous media with Triton X-100-ammonium sulfate-water aqueous two-phase system without any extractant

An aqueous two-phase system composed of Triton X-100−(NH4)2SO4−H2O was proposed for extraction and separation of tungsten(VI) from aqueous solution without using any extractant. The effects of aqueous pH, concentration of ammonium sulfate, Triton X-100 and tungsten, extracting temperature on the extraction of tungsten were investigated. The extraction of tungsten has remarkable relationship with aqueous pH and are to above 90% at pH=1.0–3.0 under studied pH range (pH=1.0–7.0) and increases gradually with increasing Triton X-100 concentration, but decreases slightly with increasing ammonium sulfate concentration. The extraction percentage of tungsten is hardly relevant to temperature but its distribution coefficient linearly increases with increasing temperature within 303.15–343.15K. The distribution coefficient of tungsten increases with the increase of initial tungsten concentration (0.1–3%) and temperature (303.15 K-333.15K). The solubilization capacity of tungsten in Triton X-100 micellar phase is independent of temperature. FT-IR analysis reveals that there is no evident interaction between polytungstate anion and ether oxygen unit in Triton X-100, and DLS analysis indicates that zeta potential of Triton X-100 micellar phase have a little change from positive to negative after extracting tungsten. Based on the above-mentioned results, it can be deduced that polytungstate anions are solubilized in hydrophilic outer shell of Triton X-100 micelles by electrostatic attraction depending on its relatively high hydrophobic nature. The stripping of tungsten is mainly influenced by temperature and can be easily achieved to 95% in single stage stripping. The tungsten (VI) is separated out from solution containing Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Al(III), Cr(III) and Mn(II) under the suitable conditions.

Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system

An integrative technology including the surfactant enhanced sorption and subsequent desorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant-enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote the desorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology. Our results showed that the cationic-nonionic mixed surfactants dodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient K*d of phenanthrene for contaminated soils treated by mixed surfactants was about 24.5 times that of soils without surfactant (Kd) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd, respectively. On the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. The desorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above 2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in 30 days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10–22 days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.

Biodegradation and Kinetics of Phenanthrene and Pyrene in the Presence of Nonionic Surfactants by Arthrobacter Strain Sphe3

Surfactant-enhanced solubilization and subsequent biodegradation of phenanthrene and pyrene from aqueous solutions by Arthrobacter strain Sphe3 was investigated. The results show that growth of Arthrobacter strain Sphe3 was increased upon increase in concentration of Tween 20 and Tween 80. Inhibition of bacterial growth was observed with increasing Triton X-100 concentrations, whereas sodium dodecyl sulfate (SDS) totally inhibited this bacterial growth. Phenanthrene and pyrene solubilization was enhanced in the presence of surfactants and found to be linearly proportional to their concentrations, above the critical micelle concentration (CMC). In addition, Tween 20 and Tween 80 enhanced the biodegradation of phenanthrene and pyrene. The high correlation coefficient (R2) values obtained at all the concentrations studied, suggest that biodegradation kinetics of both phenanthrene and pyrene in the presence of Tween 20 and Tween 80 follow first-order kinetic equation model. Experimental results suggest that Tween 20 and Tween 80 may have great potential for applications in bioremediation of these polycyclic aromatic hydrocarbon (PAH) compounds using Arthrobacter strain Sphe3.

Detergent solubilization of bovine erythrocytes. Comparison between the insoluble material and the intact membrane

Early works have shown that when biomembranes are extracted with the non-ionic detergent Triton X-100 at 4 °C, only a subset of the components is solubilized. The aim of this paper was to investigate the solubilization of a cell membrane at different Triton concentrations, and to compare the lipid composition and acyl chain order/mobility of the insoluble material with those of the original membrane. We choose bovine erythrocytes, because they have an uncommon composition, as they have a huge amount of sphingomyelin and phosphatidylcholine is almost absent. We determined the degree of order/mobility of the lipid acyl chains by EPR spectroscopy, using liposoluble spin labels. Incubation of bovine erythrocytes with increasing Triton X-100 concentrations yields decreasing amounts of insoluble material which is enriched in sphingomyelin and depleted in cholesterol. Complete lipid solubilization is achieved at a detergent/lipid ratio of about 60, which is much higher than the values reported for human erythrocytes, but is in line with results obtained in model systems. An insoluble pellet is still obtained at higher Triton concentrations, which seems to consist mainly of protein. A very high correlation is found between lipid chain mobility restrictions and sphingomyelin content in the lipid structures. The human erythrocyte membrane also fits well in this correlation, suggesting a significant role of sphingomyelin in determining acyl chain organization. The analogies and differences between our insoluble material and the detergent-resistant membranes (DRM) are discussed.

Delayed dissociation of in vitro moving actin filaments from heavy meromyosin induced by low concentrations of Triton X-100

The in vitro motility of fluorescent actin filaments over heavy meromyosin (HMM) was studied in the presence of the nonionic detergent Triton X-100. Below 0.004% Triton X-100 concentration, motility was not affected. Above 0.007%, motility was not observed because actin filaments were dissociated from HMM. In the Triton X-100 concentration range of 0.004–0.007%, the sliding actin filaments dissociated from HMM with a delay. The dissociation delay time decreased with increasing Triton X-100 concentration, increasing ATP (adenosine-5′-triphosphate) concentration, and increasing temperature. The delayed acto-HMM dissociation was absent when weak-binding kinetic intermediates of the myosin ATPase cycle (M.ATP and M.ADP-P i) were used. The presence of sliding movement was necessary to evoke the delayed acto-HMM dissociation. The acto-HMM dissociation delay was independent of actin filament length. For a given Triton X-100 concentration, the dissociation delay time was found to be inversely proportional to sliding velocity, indicating that actin filaments travel a more or less constant distance prior to dissociation from HMM. The actin-activated HMM ATPase activity was not inhibited by Triton X-100; rather, it was slightly enhanced. The results imply the presence of a motility-associated conformational change in acto-HMM.

A study of the mechanism by which some amphiphilic drugs affect human erythrocyte acetylcholinesterase activity.

The effects of the local anaesthetics procaine, tetracaine and lidocaine and of the antidepressant imipramine on human erythrocyte acetylcholinesterase were investigated. All four amphiphilic drugs inhibited enzymic activity, the IC50 (the concentration causing 50% inhibition) being about 0.40 mM for procaine, 0.05 mM for tetracaine, 0.70 mM for imipramine and 7.0 mM for lidocaine. Procaine and tetracaine inhibited acetylcholinesterase activity competitively at concentrations at which they did not perturb the physical state of the membrane lipid environment, as assessed by steady-state fluorescence polarization, whereas lidocaine and imipramine displayed mixed inhibition kinetics at concentrations at which they induced an enhancement of membrane fluidity. The question was addressed as to whether membrane integrity is a prerequisite for imipramine and lidocaine action. Membrane solubilization by 1% Triton X-100 and a decrease, by dilution, in the detergent concentration to 0.05% [which is above the Triton X-100 critical micelle concentration (c.m.c.)] did not substantially affect the inhibitory potency of the two amphiphilic drugs at their IC50; in the presence of increasing detergent concentrations the inhibitory potency of imipramine was gradually decreased, but not abolished, whereas the inhibitory effect of lidocaine was only slightly diminished, even at 1% Triton X-100. It is suggested that neither competitive nor mixed inhibition kinetics arise from conformational changes of the protein driven by a modification of the physical state of the lipid environment, but from a direct interaction of the amphiphilic drugs with acetylcholinesterase. In particular, the partial loss of the inhibitory potency of imipramine and lidocaine that is observed upon increasing Triton X-100 concentration well above its c.m.c. could be explained in terms of amphiphile partition in detergent micelles and, in turn, of a decreased effective concentration of the two inhibitors in the aqueous phase.

Role of phospholipid and protein-protein associations in activation and stabilization of soluble calcium-ATPase of sarcoplasmic reticulum

The effect of increasing concentrations of the nonionic detergent Triton X-100 on catalytic activity, stability, phospholipid content, and aggregational state of solubilized Ca2+ ion activated adenosinetriphosphatase (Ca2+-ATPase) of sarcoplasmic reticulum has been investigated. Increasing concentrations of Triton X-100 in the range 0.2-0.6% (w/v) inhibited ATP hydrolysis and p-nitrophenyl phosphate hydrolysis in parallel to the extent of 50% and 95%, respectively. Inactivation of p-nitrophenyl phosphate hydrolysis by preincubation in excess ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) at 25 degrees C was monophasic and first order at all concentrations of Triton X-100. The rate constant for inactivation increased sharply in the range 0.1-0.6% Triton X-100. At higher concentrations, the increase was less marked. Protein-protein associations of the solubilized ATPase were assessed by glutaraldehyde cross-linking and by ultracentrifugation in sucrose gradients. Both methods indicated a decrease in these associations in the 0.1-0.5% range. Cross-linking studies established that above 0.5% Triton X-100 the enzyme is greater than 90% monomeric. The amount of phospholipid associated with the ATPase, recovered from sucrose gradients, decreased from about 50 mol of phospholipid/mol of ATPase at 0.1% Triton X-100 to about 3 mol of phospholipid/mol of ATPase at 0.5% and higher concentrations. Monomeric ATPase and aggregated ATPase isolated from equilibrium mixtures of these components had similar phospholipid/protein ratios. The results indicated that with increasing Triton X-100 concentrations, inhibition of catalysis, destabilization, loss of protein-protein associations, and loss of phospholipid occur concurrently.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Triton X-100 on the electrophoretic mobility of solubilized intestinal brush border membrane dipeptidyl peptidase IV

Dipeptidyl peptidase IV (dipeptidylpeptide hydrolase, EC 3.4.14.-) was solubilized from a rat intestinal mucosal brush border membrane preparation in varying concentrations of Triton X-100. Samples of a solubilized supernatant fraction were subjected to polyacrylamide gel electrophoresis, and the activities of several brush border enzymes were measured in gel slices following elution of the enzymes from the gel. At low concentrations of Triton X-100 (0.5%), two peaks of dipeptidyl peptidase IV activity were observed suggesting the presence of two electrophoretically distinct enzymes. However with increasing Triton X-100 concentrations, the slower migrating species was converted to a faster migrating form and only one major band of activity was observed at 10% Triton. These results indicate that there is only one form of the enzyme and that care must be taken when interpreting the electrophoretic patterns of detergent solubilized membrane bound enzymes.

IRRADIATION‐ENHANCED PHYTOCHROME PELLETABILITY IN AVENA: PIGMENT RELEASE BY Mg2+‐GRADIENT ELUTION

Abstract— Gradient elution is used to facilitate controlled withdrawal of Mg2+ from phytochrome‐rich particulate fractions from irradiated Avena sativa L. shoots. The bound pigment from red‐irradiated tissue is released in a discrete band when the Mg2+ falls to just below 1 mM. This phytochrome has an apparent molecular weight of ˜300 kilodaltons upon gel filtration, indistinguishable from that of the unbound pigment in the same extract and from that in the 50,000 × g supernatant from non‐irradiated Avena. This indicates that the bound phytochrome is released as a soluble molecule at a Mg2+ concentration above that which permits release of the particulate binding partner from other particulate components. These findings appear to preclude the possibility that the phytochrome‐binding partner association can be selectively preserved at a Mg2+ level that would permit separation and analysis of phytochrome‐bearing particles without the complication of Mg2+‐induced membrane and RNP aggregation. “Cycled” Pfr (that from tissue irradiated with a red‐far red sequence prior to homogenization) is released at 0.1 to 0.2 mM Mg2+. This indicates that “cycled Pr is more tenaciously bound by the particulate fraction than is Pfr. This effect is photoreversible both by further in vivo and subsequent in vitro irradiations, suggesting that the state of the pigment, rather than of the binding partner, directly controls the tenacity of the interaction. Increasing concentrations of KCl release the pigment from the particulate fraction in the presence of 10 mM Mg2+; increasing Triton X100 concentrations do not. This confirms the ionic nature of the pigment‐particulate fraction interaction and indicates strongly that the phytochrome is located external to any membrane vesicles present (although not necessarily that it is bound directly to such vesicles). The data further suggest that phospholipid polar head groups are not primarily responsible for the binding.