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The evidence shows that the pathology of cystic fibrosis (CF) is related to mucoid secretions. Consequently, the question of what governs the viscosity of mucus is examined in detail. It is generally agreed that the mucin gel consists of polyanionic glycoproteins and a hitherto unidentified poly cationic cross-linking protein. It is proposed that larger amounts of polycations increase viscosity and, in excess, cause mucus to become a polycation. As these compounds are known to inhibit the ductal reabsorption of sodium, the two principal aspects of the pathology of CF can be related to the same mechanism. The mucus globule membrane (MGM) has been proposed as the cross-linking protein.
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Interaction of bonive serum albumin with copolymers 2-methyl-5-vinylpyridine, acrylic and methacrylic acids in different proportions in aqueous solutions was studied. It was shown, that in a wide range of ration of the components soluble cooperative complexes were formed. Ability of amphotheric copolymers to form complexes with bovine serum albumin depend both on the composition of the copolymers and on the pH of the medium. The non-polar interactions of the protein globules with hydrocarbonic 2-methyl-5-vinylpyridine chain fragments of the polyampholyte play an important role in the association of similarly charged particals. It was shown that besides this effect of chain fragments of 2-methyl-5-vinylpyridine a significant contribution in the association is made by non-polar interactions, created by methyl groups in copolymer 2-methyl-5-vinylpyridine and methacrylic acid. The association mechanism and structure of the formed complexes was studied. It was shown that complex formation is accompanied by non-equal distribution of the chain copolymer between the protein globules and appearance of asymmetric particles of the complex. A correlation between the ability of polyampholytes to bind protein and their physiological action was found.
Up to now there is no excipient for the solubilization of poorly watersoluble drugs that can be used without limitations in pharmaceutical preparations for intravasal application. The available surfactants show considerable hemolytic activity, cause anaphylactic reactions are chemically instable or have no sufficient solubilizing capacity. By polymerisation of non-ionic surfactants amphiphilic side-chain-polymers are obtained which show in vitro the same solubilization capacity as the monomers but exhibit practically no hemolytic activity. The objective of this work was to investigate, if this findings are also true for ionic oligomers. For this purpose, polyacrylic acids were substituted with long-chain alkyl amines. The solubilization capacity of these oligomers exceeds that of non-ionic amphiphilic side-chain-polymers and that of other surfactants. The hemolytic activity of the oligomers was below that of common ionic surfactants. The solubilization capacity as well as the hemolytic activity depends on the oligomers degree of substitution. Considering their high solubilization capacity and their low hemolytic activity, these oligomers may be excipients in preparations for parenteral application.
The solid-phase ethylene/maleic anhydride PE's E-5 and E-100 were used to developed a flexible integrated system of batch methods for the fractionation of albumin and gamma globulin as well as the clinically important coagulation factors. Each method for the isolation and purification of the fractions or a modification of it could also be used independently or could be added onto another method or methods. Each fraction was prepared in three steps: adsorption on solid-phase PE's elution from the PE's, and concentration by ultrafiltration or by use of PEG or both. Since the methods required no organic solvent but relied primarily on electrostatic bonding, they were essentially nondenaturing. Solid-liquid phase separation was easily accomplished by centrifugation or filtration. The yield and purity of each fraction was as follows: (1) coagulation factors II, VII, IX, and X concentrates 63% and 200-fold purified; (2) AHF 43% and 52-fold; (3) vWF 43% and 71-fold; (4) PPF, as albumin, 93% yield and 92% pure; (5) albumin 92% yield and 98.5% pure; and (6) gamma globulin 92% yield and 97.5 pure. During the preparation of gamma globulin the E-100 also tended to adsorb and remove the HBSAg and infectivity, when present.
Reversible thermal denaturation of alpha-chymotrypsin, its electrostatic complexes with carboxyl-containing polymers and the enzyme covalently bound with those polymers were studied. It was shown that the enzyme stability is affected by matrix, which manifests itself in a simultaneous decrease in enthalpy and enthropy of the reversible denaturation process and a simultaneous decrease in activation enthalpy and enthropy of denaturation. Modification and complexing of chymotrypsin with polymers has practically no effect on the activation parameters of renaturation. Differences in the original states of alpha-chymotrypsin and its derivatives and similarity of their activated states are proposed. The formation of ionic complexes of enzyme or covalent binding to polymers results in alteration of the protein native state similar to the denaturated state.
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Inbred mice--C57BL, A, C57BR, C3H and CBA strains with a high, medium and low response to sheep red blood cells (SRBC) were injected with polymeres--poly-4-vinylpyridine (P-4-VP) and polyacrilic acid (PAA), and were immunized with SRBC; production of antibody-forming cells in their spleen was determined. It was shown that the administration of P-4-VP to C57BL mice was followed by a 5--fold increase of the immune response and injection of PAA--by a 4-fold increase. Injection of P-4-VP and PAA to CBA mice increase the immune response 2.5- and 2.8-fold, respectively. In the C57BR mice P-4-VP increased the immune response 4 times, and PAA--4.7 times. Treatment of C3H mice with P-4VP was followed by a 2-fold and with PAA by a 2.4-fold increase of the immune response. Injection of P-4-VP and PAA to CBA mice had no effect on the immune response. Thus, with the increase of the immunological reactivity to sheep erythrocytes in the mentioned strains of mice there was observed a reduction of the enhancing effect of the polymeres to the immune response.
Arypsin inhibitor was concentrated from the albumin fraction of alfalfa leaf juice as insoluble complex precipitate with pectin, carboxymethylcellulose sodium salt, and dextran sulfate. The concentration degree varied from 40 to 100, and the yield of the inhibitor was 45-50%. The homogeneous inhibitor was further isolated from solution of the precipitate by affinity chromatography on Trypsin-Sepharose. The final product had a molecular weight of 6.9 kDa, high inhibitory activity (16.6 U per mg protein) and relatively high (about 30%) content of the alpha-helical form.
A novel class of biofunctional fluorescent microparticles for application in immunoassays was constructed by using the layer-by-layer self-assembly method to deposit multiple layers of fluorescently labeled polyelectrolytes onto colloidal particles, followed by deposition of a protein (immunoglobulin G, IgG) layer. Microelectrophoresis experiments revealed alternating negative and positive zeta-potentials with deposition of each successive polyelectrolyte layer, indicating that the alternate electrostatic adsorption of polyelectrolytes of opposite charge was successfully achieved. Transmission electron microscopy images showed a change of the particle surface texture after polyelectrolyte multilayer deposition. Fluorescence microscopy image (FMI) analysis provided direct measurement of the fluorescence intensity of single microparticles. The observed systematic increase of the fluorescence intensity of individual microparticles with increasing polyelectrolyte layer number from FMI analysis further demonstrated the controlled regular adsorption of polyelectrolyte layers onto the polystyrene (PS) particles. Protein immobilization onto the polyelectrolyte multilayer-coated particles was verified by the different surface properties of the microparticles with respect to surface charge under pH conditions above and below the isoelectric point of the proteins. The assembly of IgG and fluorescein isothiocyanate-labeled IgG onto polyelectrolyte multilayer-coated PS microparticles and their potential use was ultimately confirmed by a solid phase immunotest. Copyright 2001 Academic Press.
The recently presented theory of microvillar Ca(2+)signaling [Lange, K. (1999) J. Cell. Physiol.180, 19-35], combined with Manning's theory of "condensed counterions" in linear polyelectrolytes [Manning, G. S. (1969). J. Chem. Phys.51, 924-931] and the finding of cable-like ion conductance in actin filaments [Lin, E. C. & Cantiello, H. F. (1993). Biophys. J.65, 1371-1378], allows a systematic interpretation of the role of the actin cytoskeleton in ion channel regulation. Ion conduction through actin filament bundles of microvilli exhibits unique nonlinear transmission properties some of which closely resemble that of electronic semiconductors: (1) bundles of microfilaments display significant resistance to cation conduction and (2) this resistance is decreased by supply of additional energy either as thermal, mechanical or electromagnetic field energy. Other transmission properties, however, are unique for ionic conduction in polyelectrolytes. (1) Current pulses injected into the filaments were transformed into oscillating currents or even into several discrete charge pulses closely resembling that of single-channel recordings. Discontinuous transmission is due to the existence of counterion clouds along the fixed anionic charge centers of the polymer, each acting as an "ionic capacitor". (2) The conductivity of linear polyelectrolytes strongly decreases with the charge number of the counterions; thus, Ca(2+)and Mg(2+)are effective modulator of charge transfer through linear polyelectrolytes. Field-dependent formation of divalent cation plugs on either side of the microvillar conduction line may generate the characteristic gating behavior of cation channels. (3) Mechanical movement of actin filament bundles, e.g. bending of hair cell microvilli, generates charge translocations along the filament structure (mechano-electrical coupling). (4) Energy of external fields, by inducing molecular dipoles within the polyelectrolyte matrix, can be transformed into mechanical movement of the system (electro-mechanical coupling). Because ionic transmission through linear polyelectrolytes is very slow compared with electronic conduction, only low-frequency electromagnetic fields can interact with the condensed counterion systems of linear polyelectrolytes. The delineated characteristics of microvillar ion conduction are strongly supported by the phenomenon of electro-mechanical coupling (reverse transduction) in microvilli of the audioreceptor (hair) cells and the recently reported dynamics of Ca(2+)signaling in microvilli of audio- and photoreceptor cells. Due to the cell-specific expression of different types and combinations of ion channels and transporters in the microvillar tip membrane of differentiated cells, the functional properties of this cell surface organelle are highly variable serving a multitude of different cellular functions including receptor-mediated effects such as Ca(2+)signaling, regulation of glucose and amino acid transport, as well as modulation of membrane potential. Even mechanical channel activation involved in cell volume regulation can be deduced from the systematic properties of the microvillar channel concept. In addition, the specific ion conduction properties of microfilaments combined with their proposed role in Ca(2+)signaling make microvilli the most likely cellular site for the interaction with external electric and magnetic fields.
Attempts were made in this study to examine the effectiveness of coagulation and flocculation process using ferric chloride and polyelectrolyte (non-ionic polyacrylamide) for the treatment of beverage industrial wastewater. Removal of organic matter (expressed as chemical oxygen demand, COD), total phosphorus (TP) and total suspended solid (TSS) using ferric chloride and organic polyelectrolyte during coagulation/flocculation process were investigated. Also, the optimum conditions for coagulation/flocculation process, such as coagulant dosage, polyelectrolyte dosage, and pH of solution were investigated using jar-test experiment. The effect of different dosages of polyelectrolyte in combination with coagulant was also studied. The results revealed that in the range of pH tested, the optimal operating pH was 9. Percentage removals of 73, 95 and 97 for COD, TP and TSS, respectively, were achieved by the addition of 300mg/L FeCl(3).6H(2)O, whereas 91, 99 and 97% removal of COD, TP and TSS, respectively, were achieved with the addition of 25mg/L polyelectrolyte to 100mg/L ferric chloride. The volume of sludge produced, when ferric chloride was used solely, was higher compared to the use of combination of polyelectrolyte and FeCl(3).6H(2)0. The combined use of coagulant and polyelectrolyte resulted in the production of sludge volume with reduction of 60% of the amount produced, when coagulant was solely used for the treatment. It can be concluded from this study that coagulation/flocculation may be a useful pre-treatment process for beverage industrial wastewater prior to biological treatment.
Adsorption of a low linear charge density cationic polyacrylamide (CPAM) onto monodisperse silica particles has been studied over a wide range of KCl concentration (10(-3)-1 M) and pH (4-9). In parallel the surface charge density of silica particles with and without adsorbed polyelectrolyte has been determined. The adsorbed amount (Gamma) as a function of electrolyte concentration (cs) exhibits a maximum at cs approximately 0.1 M. As pH increases from 4 to 6, Gamma increases and then either reaches a plateau (cs </= 0.1 M) or decreases (cs > 0.1 M). These features can be rationalized in terms of the interplay between the different factors that govern polyelectrolyte adsorption. The effect of polyelectrolyte adsorption on the surface charge density of silica is largest at low cs. It decreases with increase of the salt content and vanishes at cs > 0.1 M. This suggests that at electrolyte concentrations lower than 0.1 M, the polyelectrolyte plays a dominant in surface charge regulation. The ratio of the adsorbed polyelectrolyte charge to total surface charge is close to unity at high pH. It increases drastically with decreasing pH and increasing salt. A large overcompensation of the substrate charge by polyelectrolyte at these conditions is established in the present work.
A theory of the dynamic electrophoretic mobility of a spherical soft particle (that is, a polyelectrolyte-coated spherical particle) in an oscillating electric field is presented. In the absence of the polyelectrolyte layer a spherical soft particle becomes a spherical hard particle, while in the absence of the particle core it tends to a spherical polyelectrolyte. The present theory thus covers two extreme cases, that is, dynamic electrophoresis of hard particles and that of spherical polyelectrolytes. Simple analytic mobility expressions are derived. It is shown how the dynamic electrophoretic mobility of a soft particle depends on the volume charge density distributed in the polyelectrolyte layer, on the frictional coefficient characterizing the frictional forces exerted by the polymer segments on the liquid flow in the polyelectrolyte layer, on the particle size, and on the frequency of the applied oscillating electric field. Copyright 2001 Academic Press.
Cellulose is deposited on silicon wafer surfaces via spin coating from a solution of cellulose in dimethylacetamide (+7% lithium chloride). The resulting cellulose layers were analyzed by ellipsometry, AFM, FTIR, ICP-MS, X-ray reflectivity, and contact angle measurements. For cellulose concentrations below 0.07 wt% the wafer surfaces are covered with a network of cellulose fibrils. For concentrations between 0.07 and 0.5 wt%, closed films with thicknesses between 1.5 and approximately 10 nm are obtained. These films are molecularly smooth (rms roughness<2 nm). Higher concentrations result in thicker films with significantly rougher surfaces (rms roughness>2 nm). The cellulose layers were used to investigate cellulose/cellulose adhesion and their modification by polyelectrolytes. To this end the sticking behavior of cellulose beads was analyzed. It is demonstrated that the sticking of the beads depends on the type, amount, and adsorption symmetry of adsorbed polyelectrolyte. Low, incomplete polyelectrolyte coverage always enhances sticking, whereas for high coverage the symmetry of the polyelectrolyte coating is very important. In this case, sticking (adhesion) is enhanced if only one surface is covered with polyelectrolyte prior to contact. If both surfaces were fully covered with polyelectrolytes before contact, sticking (adhesion) is decreased.