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Other Dyes (other + dye)
Selected AbstractsFast visible dye staining of proteins in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gels compatible with matrix assisted laser desorption/ionization-mass spectrometryELECTROPHORESIS, Issue 7-8 2004Jung-Kap Choi Abstract A fast and matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1- and 2-D SDS-PAGE) is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, zincon (ZC) and ethyl violet (EV) to form an ion-pair complex. The protocol, including fixing, staining and quick washing steps, can be completed in 1,1.5 h depending upon gel thickness. It has a sensitivity of 4,8 ng, comparable to that of colloidal Coomassie Brilliant Blue G (CBBG) staining with phosphoric acid in the staining solution. The counterion dye stain does not induce protein modifications that complicate interpretation of peptide mapping data from MS. Considering the speed, sensitivity and compatibility with MS, the counterion dye stain may be more practical than any other dye-based protein stains for routine proteomic researches. [source] Background-free, fast protein staining in sodium dodecyl sulfate polyacrylamide gel using counterion dyes, zincon and ethyl violetELECTROPHORESIS, Issue 24 2002Jung-Kap Choi Abstract A background-free, fast protein staining method in polyacrylamide gel electrophoresis using an acidic dye, zincon (ZC) and a basic dye, ethyl violet (EV) is described. It is based on the counterion dye staining technique that employs two oppositely charged dyes to form an ion-pair complex in staining solution. The selective binding of free dye molecules to proteins in acidic solution produces bluish violet-colored bands. It is a rapid and end-point staining procedure, involving only fixing and staining steps that are completed in 1,1.5 h. The detection limit of this method is 8,15 ng of protein that is comparable to the sensitivity of the colloidal Coomassie Brilliant Blue G (CBBG) stain. Due to its sensitivity and speed, this stain may be more practical than any other dye-based stains for routine laboratory purposes. [source] Fluorescent gel particles in the nanometer range for detection of metabolites in living cells,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9-10 2006Kristoffer Almdal Abstract In this present work a research program that aims at the development of sensor particles based on ratiometric detection of fluorescence from two dyes was embarked on. Such particles can in principle be used to achieve spatially and time resolved measurements of metabolite concentrations in living cells. The dyes are chosen such that the fluorescence of one dye is a function of an analyte concentration whereas the fluorescence of the other dye is independent of variations in the medium. Methods have been investigated for synthesizing such particles based on crosslinked polyacrylamide in inverse micelles in oil microemulsions. Typical sizes of the particles are tens of nanometers. Characterization methods for such particles based on size exclusion chromatography, photon correlation spectroscopy, scanning electron microscopy, and atomic force microscopy have been developed. The stability of the sensor particles and their potential as an analytical tool will be discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source] FS01.2 Contact dermatitis to disperse blue 106 in PortugalCONTACT DERMATITIS, Issue 3 2004Francisco M Brandao Disperse blue 106 is one of the most important allergenic textile dyes. We reviewed all the patients that proved to be allergic to this dye, in 10 contact clinics, in Portugal, from 01/2000 to 06/2003. In the first 2 years disperse blue 106 was only tested in suspected cases, while in 2002/2003 it was routinely tested in our standard series. A total of 8957 patients (2797M + 6160F) were tested; fifty five patients (17M + 38F)(0.6%) were allergic to the dye, with a significant difference in incidence between the 2 periods (0.2 to 0.9%); a current relevance was found in 38 (69%) patients. In 5 patients the dermatitis was considered occupational. The main localizations were the axillae (25p), the antecubital fossae and the face (13p each), the neck (11p), the feet (8p), the hands and then trunk (7p each). Thirty six out of 44 patients (80%) that were tested with disperse blue 124 were allergic to this dye. Simultaneous reactions to PPDA and to fragrance mix were observed in 12 and 11 patients, respectively. Allergy to other dyes was found in 15 patients. Blouses and skirts were the main offending garments that induced contact allergy. Although both disperse blue 106 and 124 have been reported as frequent sensitizers, it proved not to be such an important allergen in Portugal. However, if tested routinely it can pick up some unexpected relevant allergic patients. [source] Application of resazurin for estimating abundance of contaminant-degrading micro-organismsLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2001Guerin Aims: The aim of the current study was to test whether resazurin changed colour when incubated with a range of organic chemicals used as growth substrates in bioremediation studies and to determine whether resazurin was more effective in estimating microbial growth than turbidity alone (i.e. no resazurin) or use of the dye, methylene blue. Methods and Results: Resazurin was incubated with a range of organic chemicals that were used as substrates in an MPN assay. Only 1,2-dichlorobenzene, 2,4- D, glycol sulphite and sulphinol reacted to generate false positives. Resazurin was also used to estimate micro-organisms in a series of bioremediation studies. Conclusions: The results showed that resazurin was more sensitive than methylene blue or turbidity alone as an indicator of microbial growth. Significance and Impact of the Study: The significance of the current study is that resazurin should be used in MPN assays for estimating contaminant-degrading micro-organisms instead of turbidity alone or other dyes such as methylene blue. [source] Investigations of the Solvent Polarity Effect on the Photophysical Properties of Coumarin-7 Dye,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Ashish Satpati ABSTRACT Photophysical investigations of coumarin-7 (C7) dye in different solvents using absorption, steady-state fluorescence and time-resolved fluorescence measurements reveal the behavioral changes of the dye in nonpolar and other solvents. In moderate to higher polarity solvents, the experimental parameters such as fluorescence quantum yield (,f), fluorescence lifetime (,f), radiative rate constant (kf), nonradiative rate constant (knr) and Stokes' shift (,v,) follow almost linear correlations with the Lippert-Mataga solvent polarity parameter ,f but show unusual deviations in nonpolar solvents. From the observed results, it is inferred that the dye exists in a planar intramolecular charge transfer structure in moderate to higher polarity solvents, but in nonpolar solvents, the dye exists in a nonplanar structure with its 7-NEt2 group adopting a pyramidal type of configuration. Unlike some of the other coumarin dyes, namely coumarin-120 (C120) (4-CH3 -7-NH2 -1,2-benzopyrone) and coumarin-151 (C151) (4-CF3 -7-NH2 -1,2-benzopyrone), which also show similar structural changes in nonpolar and other solvents, the C7 dye does not show any activation-controlled deexcitation process in nonpolar solvents. This is attributed to the very slow flip-flop motion of the 7-NEt2 group of the C7 dye in comparison with the very fast flip-flop motion of the 7-NH2 group in the C120 and C151 dyes. Qualitative potential energy diagrams are presented to rationalize the observed results of C7 dye and to compare these with those of the other dyes such as C120 and C151. A support for the observed results and interpretation has also been obtained from quantum chemical calculations on the structures of the C7 dye. [source] A Close Look at Fluorescence Quenching of Organic Dyes by TryptophanCHEMPHYSCHEM, Issue 11 2005Sören Doose Dr. Abstract Understanding fluorescence quenching processes of organic dyes by biomolecular compounds is of fundamental importance for in-vitro and in-vivo fluorescence studies. It has been reported that the excited singlet state of some oxazine and rhodamine derivatives is efficiently and almost exclusively quenched by the amino acid tryptophan (Trp) and the DNA base guanine via photoinduced electron transfer (PET). We present a detailed analysis of the quenching interactions between the oxazine dye MR121 and Trp in aqueous buffer. Steady-state and time-resolved fluorescence spectroscopy, together with fluorescence correlation spectroscopy (FCS), reveal three contributing quenching mechanisms: 1) diffusion-limited dynamic quenching with a bimolecular quenching rate constant kdof 4.0×109s,1,M,1, 2) static quenching with a bimolecular association constant Ksof 61,M,1, and 3) a sphere-of-action contribution to static quenching described by an exponential factor with a quenching constant , of 22,M,1. The latter two are characterized as nonfluorescent complexes, formed with ,30,% efficiency upon encounter, that are stable for tens of nanoseconds. The measured binding energy of 20,30 kJmol,1is consistent with previous estimates from molecular dynamics simulations that proposed stacked complexes due to hydrophobic forces. We further evaluate the influence of glycerol and denaturant (guanidine hydrochloride) on the formation and stability of quenched complexes. Comparative measurements performed with two other dyes, ATTO 655 and Rhodamine 6G show similar results and thus demonstrate the general applicability of utilizing PET between organic dyes and Trp for the study of conformational dynamics of biopolymers on sub-nanometer length and nanosecond time-scales. [source] The effect of substituents on the aggregation and gelation of azo sulphonate dyesCOLORATION TECHNOLOGY, Issue 3 2005Kunihiro Hamada The aggregation and gelation of sodium 1-phenylazo-2-hydroxy-6-naphthalene sulphonate azo dyes containing fluoro, ethyl, n -propyl, iso -propyl, n -butyl, sec -butyl and tert -butyl groups in the para -position to the azo group have been compared with those containing methyl and trifluoromethyl groups. The behaviour of dyes containing a fluoro group was also studied using 19F NMR spectroscopy. Aqueous solutions of sodium 1-(4- sec -butylphenylazo)-2-hydroxy-6-naphthalene sulphonate at concentrations greater than 0.01 mol dm,3 became gelatinous, whereas the other dyes containing alkyl groups did not show this effect. Although the gelation of aqueous dye solutions of fluorinated dyes has been reported previously, it had not been noticed with dyes containing hydrocarbon chains. Aggregation constants have been determined, and the thermodynamic parameters found to be influenced by chain branching and by the number of carbon atoms present. Important information has been established about the spatial arrangement of fluorine in the aromatic ring. [source] | |||||||||||||