Conventional Detergents Research Articles

Advanced tool for characterization of microbial cultures by combining cytomics and proteomics

Flow cytometry approaches are applicable to recover sub-populations of microbial cultures in a purified form. To examine the characteristics of each sorted cell population, Omics technologies can be used for comprehensively monitoring cellular physiology, adaptation reactions, and regulated processes. In this study, we combined flow cytometry and gel-free proteomic analysis to investigate an artificial mixed bacterial culture consisting of Escherichia coli K-12 and Pseudomonas putida KT2440. Therefore, a filter-based device technique and an on-membrane digestion protocol were combined in conjunction with liquid chromatography and mass spectrometry. This combination enabled us to identify 903 proteins from sorted E. coli K-12 and 867 proteins from sorted P. putida KT2440 bacteria from only 5 x 10(6) cells of each. Comparative proteomic analysis of sorted and non-sorted samples was done to prove that sorting did not significantly influence the bacterial proteome profile. We further investigated the physicochemical properties, namely M (r), pI, hydropathicity, and transmembrane helices of the proteins covered. The on-membrane digestion protocol applied did not require conventional detergents or urea, but exhibited similar recovery of all protein classes as established protocols with non-sorted bacterial samples.

Crystallographic characterization of N-oxide tripod amphiphiles.

Tripod amphiphiles are designed to promote the solubilization and stabilization of intrinsic membrane proteins in aqueous solution; facilitation of crystallization is a long-range goal. Membrane proteins are subjects of extensive interest because of their critical biological roles, but proteins of this type can be difficult to study because of their low solubility in water. The nonionic detergents that are typically used to achieve solubility can have the unintended effect of causing protein denaturation. Tripod amphiphiles differ from conventional detergents in that the lipophilic segment contains a branchpoint, and previous work has shown that this unusual amphiphilic architecture can be advantageous relative to traditional detergent structures. Here, we report the crystal structures of several tripod amphiphiles that contain an N-oxide hydrophilic group. The data suggest that tripods can adapt themselves to a nonpolar surface by altering the hydrophobic appendage that projects toward that surface and their overall orientation relative to that surface. Although it is not possible to draw firm conclusions regarding amphiphile association in solution from crystallographic data, trends observed among the packing patterns reported here suggest design strategies to be implemented in future studies.

Tripod Amphiphiles for Membrane Protein Manipulation.

Integral membrane proteins (IMPs) are crucial biological components, mediating the transfer of material and information between cells and their environment. Many IMPs have proven to be difficult to isolate and study. High-resolution structural information on this class of proteins is limited, largely because of difficulties in generating soluble forms of such proteins that retain native folding and activity, and difficulties in generating high-quality crystals from such preparations. Isolated IMPs typically do not dissolve in aqueous solution, a property that arises from the large patches of hydrophobic surface necessary for favorable interactions with the core of a lipid bilayer. Detergents are generally required for IMP solubilization: hydrophobic segments of detergent molecules cluster around and shield from water the hydrophobic protein surfaces. The critical role played by detergents in membrane protein manipulation, and the fact that many IMPs are recalcitrant to solubilization and/or crystallization with currently available detergents, suggest that it should be valuable to explore new types of amphiphiles for these purposes. This review constitutes a progress report on our long-term effort to develop a new class of organic molecules, collectively designated "tripod amphiphiles," that are intended as alternatives to conventional detergents for membrane protein manipulation. One long-range goal of this research is to identify new types of amphiphiles that facilitate IMP crystallization. This review should help introduce an important biochemical need to organic chemists, and perhaps inspire new approaches to the problem.

Bolaamphiphile-Class Surfactants Can Stabilize and Support the Function of Solubilized Integral Membrane Proteins

Bolaamphiphile-class surfactants composed of two hydrophilic (maltoside) headgroups connected by long saturated alkyl chains were tested for their ability to stabilize a solubilized membrane protein, Escherichia coli diacylglycerol kinase (DAGK), and to sustain its native function. Members of this "Bis-MALT-C(18-28)" series were poor solubilizers of DAGK in the absence of conventional detergent. However, mixed micelles of the bolaamphiphiles with either dodecylphosphocholine or beta-n-decyl maltoside were more effective and enhanced DAGK's thermal stability relative to corresponding detergent-only conditions. Moreover, certain bolaamphiphiles were seen to be lipidlike by providing partial activation of DAGK's catalytic activity. Finally, addition of bolaamphiphiles to micellar NMR samples of DAGK did not result in a degradation of spectral quality, indicating their compatibility with high-resolution structural studies. To the best of our knowledge, this work represents the first documentation of the potential of bolaamphiphile-class surfactants for use in biochemical and biophysical studies of MPs.

Pre-cationization of cotton fabrics: An effective alternative tool for activation of hydrogen peroxide bleaching process

Hydrogen peroxide is a well-known environmentally safe bleaching agent for cotton fabric. However, bleaching of cotton based fabric with hydrogen peroxide requires alkaline medium (normally NaOH), stabilizer and either high temperatures or long dwell times. After bleaching and before dyeing, large amount of water is required for washing the residual un-decomposed hydrogen peroxide and the residual alkali. In this work, a new approach for bleaching cotton based fabric is postulated and investigated. The cotton fabric was scoured and cationized with NaOH and 3-cholor-2-hydroxy propyltrimethyl ammonium chloride (commercially known as CR-2000) either concurrent in one step process or separately in two step process. The scoured and cationized cotton fabric was then preceded for hydrogen peroxide bleaching. The cationic group on the cationized cotton fabric serves a dual function in the bleaching bath; the first is built-in catalyst for bleaching process and the second is powerful alkali site necessary for activation of hydrogen peroxide bleaching bath instead of NaOH. Three bleaching technique are utilized in bleaching of pre-scoured and cationized cotton fabric. These techniques are, exhaustion technique, pad-steam and cold pad-batch. The effects of cationization level, bleaching technique, bleaching parameters were systematically investigated. The fabric was monitored for strength properties, whiteness index and nitrogen content before and after the bleaching process. Results obtained show that, pre-cationization of cotton fabric provide comparable fabric whiteness in all technique investigated at much shorter reaction times and lower bleaching temperature in absence of NaOH. These results call for a breakthrough not only in bleaching of cotton based textiles but also in conventional detergent washing formulation.

Complexation of integral membrane proteins by phosphorylcholine-based amphipols

Amphiphilic macromolecules, known as amphipols, have emerged as promising candidates to replace conventional detergents for handling integral membrane proteins in water due to the enhanced stability of protein/amphipol complexes as compared to protein/detergent complexes. The limited portfolio of amphipols currently available prompted us to develop amphipols bearing phosphorylcholine-based units (PC). Unlike carboxylated polymers, PC-amphipols remain soluble in aqueous media under conditions of low pH, high salt concentration, or in the presence of divalent ions. The solubilizing properties of four PC-amphipols were assessed in the case of two membrane proteins, cytochrome b 6 f and bacteriorhodopsin. The protein/PC-amphipol complexes had a low dispersity in size, as determined by rate zonal ultracentrifugation. Short PC-amphipols (< M>≈ 22 kDa) of low dispersity in length, containing ∼ 30 mol% octyl side groups, ∼ 35 mol% PC-groups, and ∼ 35 mol% isopropyl side groups, appeared best suited to form stable complexes, preserving the native state of BR over periods of several days. BR/PC-amphipol complexes remained soluble in aqueous media at pH ≥ 5, as well as in the presence of 1 M NaCl or 12 mM calcium ions. Results from isothermal titration calorimetry indicated that the energetics of the conversion of BR/detergent complexes into BR/amphipol complexes are similar for PC-amphipols and carboxylated amphiphols.

Gels: Novel Detergents for Laundry Applications

Cleaning habits are changing day by day with the development of new technologies, new soil substrate systems and diversity of water. The rapid growth and diversity of detergents, market requires continuous consideration of new materials to meet the demand of new, improved and modified products. Detergent gels are exciting new type of detergent, represent now a days attractive subject for advanced technology. Gels are non-conventional detergents, used for fabric cleaning. Detergent gels are not as popular as conventional detergents like powders and liquids because of their high cost but from performance viewpoint detergent gels are better than conventional detergents due to its compact nature. This paper attempts to review types of detergent products, features, formulation technology, ingredients & their functional properties and applications of detergent gels.

Factors affecting wool scouring performance, yield and colour measurements of Western Australian fleece wools

A benchtop scouring procedure was used to evaluate the ability of conventional detergent scouring systems to adequately clean fleece samples from a selection of Western Australian Merino wools. Sixteen fleeces were selected from the Western Australian Department of Agriculture resource flocks, covering a wide range in yield (49.2 to 77.5%), wax (7.3 to 26.9%), suint (4.9 to 11.6%), and dust (1.4 to 16.3%) contents. Using a simple detergent-based system, 50% of the fleeces were classified as effectively scoured, based on residual wax content. When scouring liquor was not refreshed between subsamples drawn from the same fleece, wool wax, staple length and dust content in the greasy fleece accounted for 93% of the variation in the rate of residual wax increase observed in sequential 10 g samples of wool. Residual ash content also increased but the greasy fleece parameters measured were not statistically significant predictors of residual ash changes. The rate of scoured wool colour change, when sequential samples of greasy wool from the same fleece were scoured without liquor change, could be predicted from greasy fleece yields. The scouring efficiency of the more difficult to scour wools was improved by the addition of sodium carbonate to the main scouring bowls.

Oilfield Applications of Anionic Alkylpolyglucosides

Abstract In conventional detergent compositions, synergism between alkylpolyglucosides and conventional anionic surfactants is exploited. Now improved types of binary mixture of alkylpolyglucoside with innovative alkylpolyglucoside ester based anionic surfactant have been successfully applied to wellbore cleaning for the oil and gas industry. In recent years the environmental aspects of wellbore cleaning agents has become critical in environmentally sensitive areas since in offshore operations where there can potentially be accidental contamination of the marine environment with surfactants. Binary mixtures of alkylpolyglucosides and alkylpolyglucoside-based anionic surfactants showed the cleaning performance required, combined with the advantage of outstanding environmental properties.

Engine oil compositions based on PIB—succinimide combinations

AbstractAdditive packages for engine oils were prepared using PIB—succinimide combinations with different properties. PIB—succinimide‐type dispersants of various average molecular weights and dominant side effects were selected for preparing multifunctional additive combinations. A high‐molecular‐weight PIB—polysuccinimide type as viscosity‐index improver, a PIB—polysuccinimide with strong basic character as a highly effective sludge dispersant, molybdenum‐containing poly‐alkylene—polysuccinic anhydride derivatives as dispersants with complementary antifriction efficiency, and some conventional detergent, antioxidant, antiwear, and anticorrosion engine oil additives were used in engine oil compositions of various viscosity grades. The technical and economic advantages of appropriately selected and balanced additive combinations were shown by bench test results of the rheological, detergent—dispersant, and antifriction properties of the test oils.

Self-assembling Peptide Detergent A6D Directly Associates with Bovine Rhodopsin and Forms Lipid-like Vesicles

ABSTRACTMembrane protein study critically depends on detergents, which are amphilhilic molecules containing a hydrophilic “head” and a hydrophobic “tail” to mimic biological lipid bilayers to stabilize membrane proteins. However, detergents are not fully equivalent to lipid bilayers and in fact they only partly mimic lipid bilayers function. Consequently, membrane proteins in detergent solution are more or less denatured because detergents can not effectively stabilize membrane protein structures. Therefore, it is urgent to develop new types of detergents for more effectively stabilizing membrane proteins. Previously, we have reported a new type of self-assembly peptide detergents containing a hydrophilic head composed of either a negatively charged aspartic acid or a positively charged lysine and a tail of hydrophobic amino acids of six connective alanines. This new peptide detergent has been shown to be more effective for protecting membrane protein PS I structure than that the conventional detergent does. However, what type of physical structures peptide detergent can form is unclear yet. Here we presented our AFM and DSL analysis of the peptide detergent A6D, which not only form mixed micelles with n-Octyl-beta-D-Glucoside (OG) to solubilize membrane protein rhodopsin, but also can mimic lipid bilayers to keep rhodopsin in lipid-like vesicles for its structure preservation.

Mass Spectrometry of Intracellular and Membrane Proteins Using Cleavable Detergents

Detergents have been used to enhance the solubility of hydrophobic biomolecules for decades. Despite the widespread use of detergents in biochemistry, the presence of these molecules often complicates further analysis by mass spectrometry. This study presents a solution to this problem by outlining a method utilizing a novel cleavable detergent, 3-[3-(1,1-bisalkyloxyethyl)pyridin-1-yl]propane-1-sulfonate (PPS). This detergent can be used to extract protein contained within the interior of the cell by disrupting cell membranes. Once the proteins are free from the cell, PPS also assists in protein solubilization by shielding the hydrophobic regions of the newly extracted protein from unfavorable interactions with water. The added advantage of PPS over conventional detergents such as sodium dodecyl sulfate or n-octylglucoside is that the detergent properties that interfere with MALDI mass spectrometry can be eliminated prior to analysis. PPS was found to improve sensitivity in MALDI analyses of both soluble proteins and membrane proteins without degrading spectral quality. The virtues of this strategy were applied to whole cell extracts. Analysis of these extracts resulted in an overall increase in both the number of peaks observed and overall signal intensity.

Amphipols: polymers that can keep membrane proteins active in aqueous solution

Amphipols are polymeric substitutes of classic detergents, in essence ‘unimolecular membrane substitutes’, that have been used successfully to solubilize membrane enzymes. As their name suggests, they are linear amphiphilic polymers with alternating hydrophilic and hydrophobic side chains. Amphipols can solubilize integral membrane proteins by wrapping around the protein's hydrophobic transmembrane domains, forming a polar water-soluble exterior. Amphipols have a wide range of potential pharmaceutical and biochemical applications, however, until now there have been no examples where amphipols alone can support the activity of a membrane enzyme. Recently, Gorzelle et al. [1xAmphipols can support the activity of a membrane enzyme. Gorzelle, B.M. et al. J. Am. Chem. Soc. 2002; 124: 11594–11595CrossRef | PubMed | Scopus (43)See all References][1] have described an amphipol that can sustain the full functional activity of the Escherichia coli membrane protein diacyl glycerol kinase (DAGK), a homotrimeric enzyme with three transmembrane segments.DAGK is an enzyme that normally requires the presence of polar lipids, such as cardiolipin, for optimal catalytic activity. The amphipol that provided the best enzyme activity in this work was PMAL-B-100, a completely zwitterionic polyelectrolyte modified with dodecyl chains. In assays with stoichiometric amounts of complexed amphipols (where the only amphipol present was associated strongly with the enzyme, ‘0%’ PMAL-B-100), the DAGK activity was 36 units/mg, whereas with 0.5% PMAL-B-100, the activity increased to 53 units/mg. This is in comparison to enzyme activities of 51 units/mg and 1 unit/mg in conventional 0.5% decyl maltoside micelles with and without 3% cardiolipin, respectively. The importance of the zwitterionic character of PMAL-B-100 was determined by comparison with two completely anionic amphipols and with one mixed anionic and zwitterionic amphipol. In all cases, the enzyme activity decreased with increasing anionic content in the amphipol.According to the authors, ‘The observation that PMAL-B-100 can supply for DAGK all that would normally be provided by a membrane bilayer to sustain native-like structure and catalytic properties represents a benchmark in amphipol development.’ One imagines that active proteins with amphipols wrapped around them would also be more stable than proteins solubilized within conventional detergent micelles, and would thus have potential novel pharmaceutical/biotechnology applications. In addition, one can envisage the attachment of specific recognition groups to the amphipols to introduce functionality to the ‘enzyme coat’ and, perhaps, to influence enzyme activity in a controlled fashion.

Effect of ethylene oxide and propylene oxide block copolymers on the permeability of bilayer lipid membranes to small solutes including doxorubicin

The effects of ethylene oxide and propylene oxide block copolymers (pluronics) on the permeability of several weak acids and bases through bilayer lipid membranes have been studied by the methods of monitoring (1) pH shifts near planar bilayers, (2) doxorubicin fluorescence quenching inside liposomes, and (3) current transients in the presence of hydrophobic anions. It has been shown that pluronics facilitate the permeation of comparatively large molecules (such as 2- n-undecylmalonic acid and doxorubicin) across lipid bilayers, while the permeation of small solutes (such as ammonium and acetic acid) remains unaffected. Pluronics also accelerate the translocation of large hydrophobic anions (tetraphenylborate). The effect of pluronics correlates with the content of propylene oxide units: it is enhanced when the portion of polypropylene oxide block in the copolymer is increased. The action of the pluronic on lipid membrane permeability differs from the effect of the conventional detergent Triton X-100, which does not affect doxorubicin transport if added at concentrations similar to those used for pluronics. It has been proposed that pluronics accelerate the processes of solute diffusion within lipid bilayers (in a structure-dependent manner) rather than influencing the rate of solute adsorption/desorption on the membrane surface. We suppose that the effect of pluronics on doxorubicin permeation across lipid bilayers along with the known effect on the multidrug resistance protein determines its influence on the therapeutic activity of anthracycline drugs.

An improved tripod amphiphile for membrane protein solubilization.

Intrinsic membrane proteins represent a large fraction of the proteins produced by living organisms and perform many crucial functions. Structural and functional characterization of membrane proteins generally requires that they be extracted from the native lipid bilayer and solubilized with a small synthetic amphiphile, for example, a detergent. We describe the development of a small molecule with a distinctive amphiphilic architecture, a "tripod amphiphile," that solubilizes both bacteriorhodopsin (BR) and bovine rhodopsin (Rho). The polar portion of this amphiphile contains an amide and an amine-oxide; small variations in this polar segment are found to have profound effects on protein solubilization properties. The optimal tripod amphiphile extracts both BR and Rho from the native membrane environments and maintains each protein in a monomeric native-like form for several weeks after delipidation. Tripod amphiphiles are designed to display greater conformational rigidity than conventional detergents, with the long-range goal of promoting membrane protein crystallization. The results reported here represent an important step toward that ultimate goal.

Different means of administering polyethylene glycol to sheep: effect on the nutritive value of Acacia cyanophylla Lindl. foliage

AbstractPolyethylene glycol-4000 (PEG) was used to inactivate tannins in Acacia cyanophylla Lindl foliage. In the first of two experiments, four groups of five Barbarine sheep were held in metabolism crates so that intakes, apparent digestibilities, nitrogen balances and urinary excretion of allantoin could be measured. The second experiment involved four groups of three male Queue Fine de l'Ouest sheep fitted with rumen cannulae and housed in individual pens to measure rumen fermentation parameters and dry matter in situ degradation of A. cyanophylla foliage. All animals received fresh A. cyanophylla foliage ad libitum and 330 g concentrate on a daily basis. In each experiment, three groups of sheep received 20 g PEG daily, either mixed with concentrate (PEG-concentrate), dissolved in drinking water (PEG-water) or sprayed as a solution on A. cyanophylla foliage at the point of feeding (PEG-treatment). The fourth group was not supplied with PEG (control). Dry-matter intake of A. cyanophylla was low (28·3 g/kg metabolic live weight (M0·75) per day) and increased in sheep given the PEG-concentrate diet (38·2 g/kg M0·75 per day). PEG-concentrate and PEG-water diets resulted in an improvement in protein utilization as indicated by an increase of crude protein apparent digestibility (2·1 and 1·9 fold, respectively), nitrogen retention (3·2 fold with both dietary treatments) and urinary excretion of allantoin (1·9 and 1·5 fold, respectively). Improvements obtained with PEG-treatment diet were low and in general not significant (P &gt; 0·05). Low neutral-detergent fibre and acid-detergent fibre apparent digestibility coefficients of diets led to the conclusion that conventional detergent extraction techniques are questionable in determining the in vivo digestibility of cell wall constituents for tannin-rich forages. Results from rumen fluid analyses indicated that sheep given PEG-containing diets had higher ammonia-nitrogen and volatile fatty acid (VFA) concentrations (P &lt; 0·05). These results, coupled with the increase of allantoin excretion gave clear evidence that the efficiency of microbial synthesis was improved with PEG addition. The absence of change in ruminal pH and molar proportions of individual VF A suggested similar fermentation patterns among all dietary treatments. PEG supply increased the slowly degradable fraction of A. cyanophylla foliage incubated in the rumen (P &lt; 0·05), thus dry matter potential degradability (a + b) was highest in sheep given PEG-containing diets. It is concluded that the affinity of acacia tannins to PEG, increased the availability of degradable proteins, which resulted in an improvement of the nutritive value of acacia foliage. However, for practical situations, adding PEG to concentrate or to drinking water is recommended for sheep browsing A. cyanophylla trees in the field or fed indoors.

Detergent removal by non-polar polystyrene beads

Detergent removal from lipid-protein-detergent micellar solutions is the most successful strategy for reconstitution of integral membrane proteins into proteoliposomes or into two-dimensional crystals. This review establishes the potential of polystyrene beads as a simple alternative to other conventional detergent removing strategies such as dialysis, gel chromatography and dilution. Kinetics and equilibrium aspects of removal of different detergents by hydrophobic adsorption onto polystyrene beads have been systematically investigated. A mechanism of adsorption onto polystyrene beads is proposed and provide useful information about the use of these beads in reconstitution experiments. The usefulness of this detergent removal strategy to produce quasi-ideal proteoliposomes is evaluated by considering the morphology and the size of the reconstituted vesicles, the homogeneity in size and protein distribution, the final protein orientation and the permeability of resulting proteoliposomes. Finally, the advantages of detergent removal by polystyrene beads as an alternative to conventional dialysis in two-dimensional crystallization trials are evaluated through review of recent structural reconstitution studies.

Neuere Entwicklungen auf dem Gebiet der Wasch- und Reinigungsmittel / Recent developments in the field of laundry detergents and cleaners

Quite a lot of key developments and innovations have occurred in the dynamic market of laundry detergents and cleaners in recent years. A detailed review on changes regarding the composition of powder and liquid laundry detergents and their manufacturing technology is presented. Also, differences and common characteristics between compact/super-compact detergents and conventional detergents are discussed. New developments with modern washing machines, changing consumer attitudes and washing habits as well as official directives regarding environmental compatibility have exerted quite a considerable influence on the composition of modern detergents and their ingredients such as surfactant combinations, bleach systems and enzyme cocktails. Ongoing trends regarding laundry detergents and cleaners as well as future prospects are discussed.

Overbased lubricant detergents – a comparative study

AbstractOverbased detergents are commonly used in automotive and marine lubricants. Their main functions are to neutralise potentially corrosive acids and to contribute to engine cleanliness. The major types of overbased detergents that are produced commercially are phenates, sulphonates and salicylates. This paper describes the chemistry of these additive classes and reviews their properties and performance in bench and engine tests. The paper also describes a new class of overbased detergents, where novel chemistry has been used to produce new types of highly overbased phenate, sulphonate, and salicylate. These new products exhibit significant improvements in properties and performance over conventional detergents. Evidence from bench and engine tests is presented to demonstrate the benefits of the new detergent types. An appendix gives more detail on the results of tribological tests on these new detergents.

The isolation and characterisation of a major outer-membrane protein from Bacteroides distasonis.

An outer-membrane protein (OMP) was isolated from a clinical strain of Bacteroides distasonis. Changes in growth media did not appreciably affect the appearance of this protein in crude outer-membrane preparations examined by SDS-PAGE. However, the proportion of the protein relative to other OMPs was greater in 24-h cultures than in 48-h cultures. The protein could not be readily solubilised by various conventional detergent extraction techniques but treatment of the insoluble material at 100 degrees C with SDS released the protein, as did overnight extraction at 37 degrees C with SDS. This OMP was heat-modifiable, and thus was similar to the OmpA protein of Escherichia coli, with a faster mobility on SDS-PAGE when solubilised at 25 degrees C than at 100 degrees C. The critical temperature for conversion was between 80 degrees C and 90 degrees C. Because of the characteristic heat-modifiability, the protein was called B. distasonis HMP-1 (heat modifiable protein-1). Overnight exposure to EDTA or NaCl at 37 degrees C favoured conversion of the 25 degrees C form to the 100 degrees C form. In intact cells, the protein was labelled by a cell-surface radio-iodination procedure, and thus is at least partially exposed at the cell surface. No reactions between the B. distasonis HMP-1 and antibodies to either E. coli OmpA or E. coli porin were found by Western blot analysis. A B. distasonis OM preparation containing predominantly HMP-1 had pore-forming ability in a liposome assay. This study is the first report of the isolation and characterisation of a heat-modifiable OMP in Bacteroides, and it is the first description of pore-forming activity in a Bacteroides OM fraction.