Induction of metachromasia and circular dichroism in the dye 1,9-dimethyl methylene blue by S. aureus wall teichoic acid

Teichoic acid (TA) isolated from the Gram-positive bacteria Staphylococcus aureus induces blue shifted metachromasia in the dye 1,9-dimethyl methyleneblue (DMMB). Results of conductometric titrations show that DMMB binds to TA with 1:1 stoichiometry. Unlike DNA, this TA does not induce a definite metachromatic band in the dye acridine orange. S. aureus TA also induces strong circular dichroism (CD) in this dye with molar ellipticity value of the order of 10(4). This induction of CD in DMMB supports our earlier inference that TA in dilute solution at neutral pH has a helical conformation, and is not a random coil polymer.     

Absorption and fluorescence studies on interaction between cationic dyes and Klebsiella K7 capsular polysaccharide.

Interaction of cationic dyes, pinacyanol chloride, acridine orange and phenosafranin, with Klebsiella K7 capsular polysaccharide has been investigated by spectrophotometric and spectrofluorometric measurements. The acidic polysaccharide induce a metachromatic blue shift of the absorption band of pinacyanol chloride from 600 nm to 495 nm, indicating strong metachromasy. Stoichiometry of polyanion and dye cation (1:1.5) in the polymer-dye compound formed by the interaction between pinacyanol chloride dye and K7 polymer indicate that both glucuronic acid and pyruvic acid act as the potential anionic sites for interaction. Both spectrophotometric titration of pinacyanol chloride and spectrofluorometric titration of acridine orange and phenosafranin dyes by the polymer gave quite comparable equivalent weights for the polymer. Dye-polymer interaction studies indicated induction of metachromasy in the cationic dye by the anionic biopolymer, establishing its chromotropic character.     

花生壳粉生物吸附水溶液中阴离子染料的研究

An untried,low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for hiosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g.initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively.When the dye concentration was 50 mg" L-1 the percentages of dyes sorbed was 95.5 % in Am, 91.3 % in SY and 94.98 % in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes whensorbent dose of 5.0 g·L^-1 and the sorbent particle size in 80—100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.     

One-bath trichrome staining: Investigation of a general mechanism based on a structure-staining correlation analysis

Summary Dye pairs of contrasting colours were selected from acid dyes of varied chemical characteristics. The 44 dye pairs were investigated in a one-bath trichrome staining system in which the dye-baths were strongly acid. Dye concentrations, concentration ratios and staining times were varied for each dye pair. Thirty dye pairs stained collagen fibres distinctly different colours to muscle cytoplasm, while 14 dye pairs gave muddy, non-selective staining. Comparison of dye structures showed that in selective pairs the larger dye always stained the collagen fibres, with cytoplasm being coloured by the smaller species. With 28/30 of the selective dye pairs the differences in anionic weights of the dyes was > 200. However, in dye pairs giving non-selective staining, the anionic weights of the members of 13/14 of the dye pairs differed by < 200. As no other structural feature correlated so clearly with selectivity, it was concluded that the selectivity of one-bath trichromes is diffusion-rate controlled, involving the interaction of differentially permeable tissue sites (collagen being more permeable than muscle cytoplasm) with dyes diffusing at different rates (large dyes slower than small). In keeping with this, lengthening staining times reduced staining selectivity. The rate control mechanism suggested a rational trouble-shooting guide for one-bath trichromes, encompassing such practical factors as dye concentration, embedding medium, fixative, dye-bath pH, section thickness and staining time.     

Radiation synthesis, characterization and dye adsorption of alginate-organophilic montmorillonite nanocomposite

In this paper, the preparation, characterization and dye adsorption properties of nanocomposite (calcium alginate/organophilic montmorillonite) (CA/OMMT) were investigated. A new nanocomposite consisting of alginate and OMMT was prepared by polymerization using γ-rays irradiation as initiator. Physical characteristics of CA/OMMT were studied using X-ray diffraction (XRD), infrared spectrophotometery (IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). Two textile dyes, acid green B and direct pink 3B, were used as model anionic dye. Factors affecting dye sorption, such as pH, sorbent concentration and temperature of each dye solution were extensively investigated. It was found from the study that the sorption of dyes by the nanocomposite is pH-dependent and maximum sorption was obtained at pH 2. The thermodynamic data showed that dye adsorption onto alginate was spontaneous, exothermic, and a physisorption reaction. On the basis of the data of the present investigation, one could conclude that the as-prepared adsorbents exhibited excellent affinity for the dye, and can be applied to treat wastewater containing anionic dyes.     

Spectrophotometric study of the relative affinities of teichoic acid for different metal ions.

Spectrophotometric study of the relative affinities of teichoic acid (TA) for Na+, Ca2+, Mg2+, Cd2+, Hg2+, Cu2+ and Pb2+ described on the basis of the disruption of metachromasia of dye 1,9-dimethyl methylene blue (DMMB)-polyanion (TA) system has revealed the following sequence of relative affinities of TA for these metals: Na+ < Ca2+ < or = Mg2+ < Cd2+ < Hg2+ < Cu2+ < Pb2+. Some of the metal ions particularly Pb2+ and Hg2+ have specific interactions with the dye, and induce distinct metachromatic band of the dye even in the absence of the polyanion.     

Molecularly imprinted polymers for some reactive dyes

Depending upon their structure, azo- and anthraquinonic dyes are the two major classes and together represent 90% of all organic colorants. Adsorption of dye molecules onto a sorbent can be an effective, low-cost method of color removal. Most of the techniques used for removal of dyes are of high production cost, and the regeneration also makes them uneconomical. There is much interest in the development of cheaper and effective newer materials for use as adsorbents. Molecular imprinting is a new kind of materials that can be alternative adsorbents. In this study, molecularly imprinted polymers of three textile dyes (Cibacron Orange P-4R, Cibacron Red P-4B, Cibacron Black PSG) were prepared. Methacrylic acid was used as a monomer for red and orange dyes and acrylamide was used for black dye. Methanol:acetonitrile was used as a porogen. The selective recognition ability of the molecularly imprinted polymers was studied by an equilibrium-adsorption batch method. The adsorption data are for Cibacron Black PSG 65% and nonimprinted polymer (NIP) 25%; Cibacron Red P-4B 72% and NIP 18%; and Cibacron Orange P-4R 45% and NIP 10%, respectively. Dye-imprinted polymers were used as a solid-phase extraction material for selective adsorption from wastewater of textile factory.     

MOLECULARLY IMPRINTED POLYMERS FOR SOME REACTIVE DYES

Depending upon their structure, azo- and anthraquinonic dyes are the two major classes and together represent 90% of all organic colorants. Adsorption of dye molecules onto a sorbent can be an effective, low-cost method of color removal. Most of the techniques used for removal of dyes are of high production cost, and the regeneration also makes them uneconomical. There is much interest in the development of cheaper and effective newer materials for use as adsorbents. Molecular imprinting is a new kind of materials that can be alternative adsorbents. In this study, molecularly imprinted polymers of three textile dyes (Cibacron Orange P-4R, Cibacron Red P-4B, Cibacron Black PSG) were prepared. Methacrylic acid was used as a monomer for red and orange dyes and acrylamide was used for black dye. Methanol:acetonitrile was used as a porogen. The selective recognition ability of the molecularly imprinted polymers was studied by an equilibrium–adsorption batch method. The adsorption data are for Cibacron Black PSG 65% and nonimprinted polymer (NIP) 25%; Cibacron Red P-4B 72% and NIP 18%; and Cibacron Orange P-4R 45% and NIP 10%, respectively. Dye-imprinted polymers were used as a solid-phase extraction material for selective adsorption from wastewater of textile factory.     

Synthesis of beta-cyclodextrin and starch based polymers for sorption of azo dyes from aqueous solutions

Three beta-cyclodextrin (polymers 1-3) and a starch-based (polymer 4) polymers were synthesized using hexamethylene diisocyanate (HMDI) as a cross-linking agent in dry dimethylformamide and used as a sorbent for the removal of some selected azo dyes from aqueous solutions. The cross-linked polymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric and differential scanning calorimetric analysis. Results of sorption showed that cyclodextrin and starch based polymers can be effectively used as a sorbent for the removal of anionic azo dyes. The Influence of the amide groups and the chemical structure of azo dyes are also studied. Results of sorption experiments showed that these adsorbent exhibited high sorption capacities toward Direct Violent 51 (80% for polymer 1, 69% for polymer 2, 70% for polymer 3 and 78% for polymer 4). The sorption capacity of dyes on the polymers was dependent on the presence of sulfonate groups of the anionic dyes. In order to explain the results an adsorption mechanism mainly physical adsorption and interactions such as hydrogen bonding, ion-exchange due to the nature of the polymer network and the formation of an inclusion complex due to the beta-CD molecules through host-guest interaction is proposed.     

Complexation of polymethine dyes with human serum albumin: a spectroscopic study

Non-covalent interactions between polymethine dyes of various types (cationic and anionic thiacarbocyanines as well as anionic oxonols and tetracyanopolymethines) and human serum albumin (HSA) were studied by means of absorption, fluorescence and circular dichroism (CD) spectroscopies. Complexation with the protein leads to a red shift of the dye absorption spectra and, in most cases, to a growth of the fluorescence quantum yield (Phif; for oxonols this growth is very small). The binding constants (K) obtained from changing the absorption spectra and Phif vary from 10(4) to (5-6) x 10(7) M(-1). K for the anionic dyes is much higher than for the cationic dyes (the highest K was found for oxonols). Interaction of meso-substituted anionic thiacarbocyanines with HSA results in cis-->trans isomerization and, as a consequence, an appearance and a steep rise of dye fluorescence. Binding to HSA gives rise to dye CD signals and in many cases is accompanied by aggregation of the dyes. These aggregates often exhibit biphasic CD spectra. The aggregates formed by the dyes alone are decomposed in the presence of HSA.     

Mutagenicity test of dyes used in cosmetics with the Salmonella/mammalian-microsome test.

37 dyes including 3 anthraquinone, 22 azo; 5 xanthene, 5 fluorandiol, and 2 thioindigo dyes, were tested for mutagenic potential with the Salmonella/mammalian-microsome test. Two frame-shift histidine mutants (TA1537 and TA98) and two base-pair substituted histidine mutants (TA1535 and TA100) of Salmonella typhimurium were employed. Both the spot test and the plate-incorporation assay indicated that one azo dye, D&C Orange No. 17, was mutagenic with three of the bacterial test strains. The mutagenic response of D&C Orange No. 17 was depressed by the addition of the microsomal fractions from rat livers. Of the chemicals used to synthesize D&C Orange No; 17 was depressed by the addition of the microsomal fractions from rat livers. Of the chemicals used to synthesize D&C Orange No. 17, beta-naphthol was not mutagenic but 2,4-dinitroaniline was mutagenic to the same Salmonella strains as D&C Orange No. 17 . Dimethyl sulfoxide extracts of lipsticks of similar formula but without D&C Orange No. 17 were tested in the plate incorporation assay. Only those containing D&C Orange No. 17 were mutagenic and the dye was mutagenic at concentrations consumed in normal daily use.     

Microspectrophotometric Analysis of Accumulation of the Fluorones K-Fluorescein, Rose Bengal and Phloxine Red in Living Plant Cells

Spectrophotometry investigations of dye solutions in different media and of living stained cells from the upper epidermis of the scaleleaf of Allium cepa were carried out with the dyes K-fluorescein, rose Bengal and phloxine red to elucidate the mechanism of the accumulation of these dyes in the cytoplasm, the nucleus and the cell sap. Thin layer chromatography and paper electrophoresis indicate that the K-fluorescein used here contains no detectable contaminants. Besides the main component, rose Bengal contains two components in small quantities with Rf values of 0.64 and 0.57, plus three more components in traces. Besides the two main components (Rf values of 0.83 and 0.73), phloxine red also contains five more components in traces. Electrophoretic investigations reveal that in aqueous solution the fluorones rose Bengal and phloxine red from pH 2.0-11 show a migration toward the anode. K-fluorescein from pH 2.9-10.4 shows a migration toward the anode, but at pH 1.9 a migration toward the cathode. By shaking aqueous solutions of K-fluorescein, rose Bengal and phloxine red at different pH values with different organic solvents, the above used stainings show different spectral absorption curves according to the polarity of the solvent. The position of the absorption maxima and the shape of the absorption curves of these three anionic dyes lead to the conclusion that the staining of the living cytoplasm and nucleus is due to ion accumulation by means of the “ion trap mechanism” within the aqueous phase of the cytoplasm (cytosol) and the nucleus. Adsorption of dye particles in the protein phase of the cytoplasm cannot be excluded. There seems to be a fundamental difference in the vital staining of the protoplasm by anionic and cationic dyes, the latter apparently accumulating as neutral dye molecules in the lipid phase of the protoplasm. The concentration of the dyes used in the living cytoplasm (cytosol) is approximately 0.2-0.05%. During natural and artificial displacement of K-fluorescein from the cytoplasm to the vacuole, it appears that accumulation of the dye within the vacuole is performed through an ion trap mechanism in the form of bivalent ions. Along with natural displacement, it is possible that ion accumulation also occurs in metabolic products.     

Induction of metachromasia and circular dichroism in the dye 1,9-dimethyl methylene blue by ATP

The theoretical prediction of induction of metachromasia [V Czikkely, H D Foersterling & H Kuhn (1970), Chem Phys Lett, 6,207] in a dye by a polyanion having only four to six anionic sites is proved experimentally, for the first time, in ATP--1.9-dimethyl methylene blue system. The findings show that ATP induces metachromasia in the dye at neutral pH, when ATP molecule remains fully charged providing four anionic sites to the dye cations. Conductometric titration shows that the dye molecules bind stoichiometrically to ATP (four dyes/ATP). However ATP at acidic pH and ADP and AMP at any pH fail to induce metachromasia. This is also the first report of induction of circular dichroism in bound dyes by ATP. Though the chiral moiety of ribose sugar in ATP may induce dichroism in the bound achiral dyes, the observed high molar ellipticity values indicate aggregation of bound dyes with twist in one sense initiated by the twisted conformation of the triphosphate chain in ATP. This inference on the state of conformation of ATP in its native environment is in agreement with that derived from PMR and spin lattice relaxation technique. It is thus interesting that the conformation of crystalline disodium ATP, as concluded from X-ray crystallography, is maintained by tetrasodium ATP in dilute aqueous solution--the native environment of ATP.     

Application of fluorophore-assisted carbohydrate electrophoresis to analysis of disaccharides and oligosaccharides derived from glycosaminoglycans

Various combinations of fluorescent dyes, polyacrylamide gels, and electrophoresis buffers were tested by fluorophore-assisted carbohydrate electrophoresis (FACE) for the purpose of analyzing sulfated and nonsulfated glycosaminoglycan (GAG) oligosaccharides in which disaccharides and low-molecular weight oligosaccharides were included. A nonionic fluorescent dye was found to be suitable for analyzing sulfated disaccharides derived from sulfated GAGs (e.g., chondroitin sulfate, dermatan sulfate) because sulfated disaccharides themselves had enough anionic potential for electrophoresis. The migration rates of chondroitin sulfate (CS) disaccharides in polyacrylamide gels were affected by the number of sulfate residues and the conformation of each disaccharide. When an anionic fluorescent dye, 8-aminonaphthalene-1,3,6-trisulfonic acid disodium salt (ANTS), was coupled with sulfated GAG oligosaccharides, nearly all of the conjugates migrated at the electrophoretic front due to the added anionic potential. Nonsulfated hyaluronan (HA) oligosaccharides (2-16 saccharides) were subjected to electrophoresis by coupling with a nonionic fluorescent dye, 2-aminoacridone (AMAC), but did not migrate in the order of their molecular size. Especially di-, tetra-, hexa-, and octasaccharides of HA migrated in the reverse order of their molecular size. HA/CS oligosaccharides were able to migrate in the order of their chain lengths by coupling with an anionic fluorescent dye in a nonborate condition.     

Demonstration of amyloid with Mesitol WLS-Congo Red: Application of a textile auxiliary to histochemistry

Summary Previous histochemical investigations demonstrated similarities in the binding of Congo Red and other direct cotton dyes by amyloid and cellulose. It seemed threfore of interest to determine whether or not the cellulose-like reactivity of amyloid extends also to dye solutions containing an anionic reserving agent. These reagents are used in the dyeing of wool-cellulose (Halbwolle) fabrics to prevent binding of direct cotton dyes by proteins. Mesitol WLS-Congo Red solutions stained amyloid selectively; other tissue structures, except some hyaline deposits in arterioles, remained unstained. The cause of this non-specific reaction could not be determined with certainty. Therefore, the alkaline Congo Red method is recommended for histochemical identification of amyloid. However, the Mesitol WLS-Congo Red technic was very useful for demonstration of amyloid after prolonged storage of tissues in formalin; amyloid in such material showed little or no reactivity with the alkaline Congo Red or the Sirius dye methods. This pilot study indicates that anionic reserving agents can be effectively employed under conditions of histochemical technics.     

Electrostatic forces control the penetration of membranes by charged solutes

Using fluorescent, anionic dyes such as carboxyfluorescein as model solutes, it is shown that the forces allowing such solutes to be retained within sealed lipid vesicles, against a large concentration gradient, can be primarily electrostatic in nature. At temperatures distant from that of the ordered-fluid lipid phase transition a small number of the anionic dye molecules trapped within lipid vesicles are capable of traversing the lipid bilayer and establishing an electrical diffusion potential across the membrane. Further solute movement can then only occur with the concomitant permeation of ions which restore electrical balance. A significant flux of dye can be triggered by (a) increasing the permeability of the membrane to ions (for example by the addition of ionophores such as gramicidin, or by allowing the lipid to approach a phase transition) or by (b) adding lipophilic counterions such as tetraphenylborate or dinitrophenol to the system.     

Electrostatic forces control the penetration of membranes by charged solutes

Using fluorescent, anionic dyes such as carboxyfluorescein as model solutes, it is shown that the forces allowing such solutes to be retained within sealed lipid vesicles, against a large concentration gradient, can be primarily electrostatic in nature. At temperatures distant from that of the ordered-fluid lipid phase transition a small number of the anionic dye molecules trapped within lipid vesicles are capable of traversing the lipid bilayer and establishing an electrical diffusion potential across the membrane. Further solute movement can then only occur with the concomitant permeation of ions which restore electrical balance. A significant flux of dye can be triggered by (a) increasing the permeability of the membrane to ions (for example by the addition of ionophores such as gramicidin, or by allowing the lipid to approach a phase transition) or by (b) adding lipophilic counterions such as tetraphenylborate or dinitrophenol to the system.     

Developing azo and formazan dyes based on environmental considerations: Salmonella mutagenicity

In previous papers, the synthesis and chemical properties of iron-complexed azo and formazan dyes were reported. It was shown that in certain cases iron could be substituted for the traditionally used metals such as chromium and cobalt, without having an adverse effect on dye stability. While these results suggested that the iron analogs were potential replacements for the commercially used chromium and cobalt prototypes, characterization of potentially adverse environmental effects of the new dyes was deemed an essential step in their further development. The present paper provides results from using the Salmonella/mammalian microsome assay to determine the mutagenicity of some important commercial metal complexed dyes, their unmetallized forms, and the corresponding iron-complexed analogs. The study compared the mutagenic properties of six unmetallized azo dyes, six commercial cobalt- or chromium-complexed azo dyes, six iron-complexed azo dyes, six unmetallized formazan dyes, and six iron-complexed formazan dyes. The results of this study suggest that the mutagenicity of the unmetallized dye precursors plays a role in determining the mutagenicity of the iron-complexes. For the monoazo dye containing a nitro group, metal complex formation using iron or chromium decreased or removed mutagenicity in TA100; however, little reduction in mutagenicity was noted in TA98. For the formazan dye containing a nitro group, metal-complex formation using iron increased mutagenicity. Results varied for metal-complexes of azo and formazan dyes without nitro groups, but in general, the metal-complexed dyes based on mutagenic ligands were also mutagenic, while those dyes based on nonmutagenic ligands were nonmutagenic.     

Novel cationic triazine dyes for protein purification

The effectiveness of a new immobilized cationic triazine dye was investigated alongside two new amphoteric triazine dyes and two well known anionic triazine dyes, Procion Red H-3B and Procion Blue H-B, as chromatographic media for binding four familiar proteases-trypsin, chymotrypsin, thrombin and carboxypeptidase-B-as well as a typical oxidoreductase, lactate dehydrogenase, and human serum albumin. The new affinity adsorbent, CL-Sepharose-immobilized Cationic Dye, specifically binds trypsin-like proteases such as trypsin, thrombin, and carboxypeptidase-B, but none of the other proteins tested. In contrast, the amphoteric and anionic immobilized dyes bind all the other proteins tested in a similar fashion. The specificity of the cationic dye was exploited in the resolution of trypsin and chymotrypsin from a crude activated bovine pancreatic extract. The procedure described here affords trypsin with specific activity of 7400 units/mg with a 79% overall yield in a single step. The immobilized cationic dye, unlike previously reported adsorbents for trypsin, is inexpensive, readily synthesized, and displays a workable capacity of 4000 trypsin units or 0.55 mg protein/g moist weight gel (1.2 mumol dye/g moist weight gel) from a crude bovine pancreatic extract and, thus, is potentially amenable to process-scale operations.     

The role of phosphotungstic and phosphomolybdic acids in connective tissue staining I. Histochemical studies

Synopsis An investigation of the role of phosphotungstic and phosphomolybdic acids in Mallory-like trichrome methods showed unexpectedly that, rather than acting as mordants to anionic dyes, these polyacids selectively blocked staining of all tissue components other than connective tissue fibres to Aniline Blue and other similar fibrereactive dyes. Connective tissue components were found to contain residues resembling histidine that are easily accessible to anionic dyes. Blocking towards typical anionic dyes for demonstrating plasma proteins, such as Biebrich Scarlet, was also demonstrated but was less complete. The blockade of both types of dye was labile if the staining times were extended; plasma dyes were more sensitive than fibre dyes in this respect. Histochemical reactions for tyrosine residues were blocked. In connective tissue, phosphotungstic acid did not block histidine residues demonstrable by the coupled tetrazonium reaction with previous iodination. Thus it is postulated that differential trichrome staining occurs by binding of Aniline Blue to basic residues in the connective tissue not blocked by phosphotungstic acid and subsequent replacement of the blocking agent by an anionic dye. The binding of phosphotungstic acid to both epithelium and connective tissue was demonstrated by the quenching of autofluorescence in these regions and by the reduction of the bound PTA to blue coloured products with titanium trichloride.