The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform
Devendra Mohan - One of the best experts on this subject based on the ideXlab platform.
-
excited state characteristics of Acridine Dyes acriflavine and Acridine orange
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2003Co-Authors: Vijay K Sharma, P D Sahare, Ramesh C Rastogi, S K Ghoshal, Devendra MohanAbstract:The magnitude of the Stokes shift (frequency shifts in absorption and fluorescence spectra) is observed on changing the solvents and further has been used to calculate experimentally the dipole moments (ground state and excited state) of acriflavine and Acridine orange dye molecules. Theoretically, dipole moments are calculated using PM 3 Model. The dipole moments of excited states, for both molecules investigated here, are higher than the corresponding values in the ground states. The increase in the dipole moment has been explained in terms of the nature of the excited state. Acriflavine dye overcomes the non-lasing behaviour of Acridine orange due to quaternization of the central nitrogen atom.
Joseph Molnar - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of plasmid curing by 9 aminoAcridine and two phenothiazines in the presence of proton pump inhibitor 1 2 benzoxazolyl 3 3 3 trifluoro 2 propanone
International Journal of Antimicrobial Agents, 2003Co-Authors: Gabriella Spengler, Andras Miczak, Edit Hajdu, Masami Kawase, Leonard Amaral, Joseph MolnarAbstract:Abstract Plasmid-containing bacteria often cause serious therapeutic failure during the treatment of infectious diseases. The selection of resistant-mutant strains and the transfer of mobile genetic determinants (such as plasmids and transposons) of resistance promote increased antibiotic resistance. In the last 30 years the antiplasmid effect of Acridine Dyes, ethidium bromide, sodium dodecyl sulphate and phenothiazines was described. The main aim of this study was to test the mechanism of the antiplasmid effect of promethazine and 9-aminoAcridine on doxycycline-resistant enteric bacteria. The antiplasmid effects of promethazine and 9-aminoAcridine were studied on plasmid elimination of native plasmid DNA and plasmid DNA isolated from drug-treated cells of plasmid-containing Escherichia coli , Citrobacter freundii and Enterobacter cloacae . The effects of some phenothiazines on plasmid profiles of bacterial strains isolated from urinary tract infections were analysed by agarose gel electrophoresis. Various complex of plasmid DNA were identified in the presence of promethazine, trifluoperazine and 9-aminoAcridine in the agarose gel electrophoresis. Doxycycline resistance of tested enteric bacteria was the target of ‘curing’ in the presence of promethazine and trifluoperazine. The frequency of elimination of tetracycline resistance was low despite the formation of antiplasmid compounds complex with isolated plasmid DNA. Tetracycline resistance plasmid was isolated and re-transformed. The plasmid curing effects of promethazine, trifluoperazine and 9-aminoAcridine were increased in the presence of a trifluoroketone proton pump inhibitor on E. coli K12 LE140 strain in a model experiment. We propose that the inefficient penetration of antiplasmid compounds could be responsible for the weak plasmid-curing effect in some clinical isolates and that membrane active, calmodulin- and proton pump inhibitors may be combined for plasmid curing in antibiotic-resistant bacteria.
Stefan W Hell - One of the best experts on this subject based on the ideXlab platform.
-
negatively charged red emitting Acridine Dyes for facile reductive amination separation and fluorescent detection of glycans
Analytical Chemistry, 2020Co-Authors: Maksim A Fomin, Jan Seikowski, Vladimir N Belov, Stefan W HellAbstract:Capillary gel electrophoresis with laser-induced fluorescence detection (CGE-LIF) has become a key method in high-throughput glycan analysis. At present, CGE-LIF relies on the green fluorophore 8-aminopyrene-1,3,6-trisulfonic acid (APTS). However, APTS has moderate reactivity in labeling of glycans and a fixed selectivity profile. Here, we report synthesis of red-emitting and highly reactive fluorescent tags for glycan derivatization. The design is based on a 9-aminoAcridine scaffold with various acceptor groups at C-2 (CN, SO2R) and a primary amino group at C-7 for conjugation via reductive amination. These reactive Dyes exhibit absorption maxima close to 450 nm and emission above 600 nm. They readily undergo conjugation with reducing sugars at the desired 1:1 stoichiometry. The red emission of conjugates with a maximum at 610-630 nm can be observed under excitation with 488 nm light and detected separately from the APTS-labeled oligosaccharides. Phosphorylated 7,9-diaminoAcridine-2-SO2R derivatives with variable amounts of negative charges provide high mobilities of glycoconjugates on polyacrylamide gel electrophoresis (PAGE), as compared with those of APTS. We further demonstrate their utility by labeling and separating a maltodextrin ladder and sialyllactose isomers. The new Dyes are expected to cross-validate and increase the glycan identification precision in CGE-LIF and help to reveal "heavy" glycans, yet undetectable with the APTS label.
Gopinatha Suresh Kumar - One of the best experts on this subject based on the ideXlab platform.
-
binding of fluorescent Acridine Dyes Acridine orange and 9 aminoAcridine to hemoglobin elucidation of their molecular recognition by spectroscopy calorimetry and molecular modeling techniques
Journal of Photochemistry and Photobiology B-biology, 2016Co-Authors: Sabyasachi Chatterjee, Gopinatha Suresh KumarAbstract:The molecular interaction between hemoglobin (HHb), the major human heme protein, and the Acridine Dyes Acridine orange (AO) and 9-aminoAcridine (9AA) was studied by various spectroscopic, calorimetric and molecular modeling techniques. The Dyes formed stable ground state complex with HHb as revealed from spectroscopic data. Temperature dependent fluorescence data showed the strength of the dye-protein complexation to be inversely proportional to temperature and the fluorescence quenching was static in nature. The binding-induced conformational change in the protein was investigated using circular dichroism, synchronous fluorescence, 3D fluorescence and FTIR spectroscopy results. Circular dichroism data also quantified the α-helicity change in hemoglobin due to the binding of Acridine Dyes. Calorimetric studies revealed the binding to be endothermic in nature for both AO and 9AA, though the latter had higher affinity, and this was also observed from spectroscopic data. The binding of both Dyes was entropy driven. pH dependent fluorescence studies revealed the existence of electrostatic interaction between the protein and dye molecules. Molecular modeling studies specified the binding site and the non-covalent interactions involved in the association. Overall, the results revealed that a small change in the Acridine chromophore leads to remarkable alteration in the structural and thermodynamic aspects of binding to HHb.
Zhong Fang Liu - One of the best experts on this subject based on the ideXlab platform.
-
resonance rayleigh scattering spectra of interaction of sodium carboxymethylcellulose with cationic Acridine Dyes and their analytical applications
Analytica Chimica Acta, 2005Co-Authors: Shao Pu Liu, Sa Chen, Zhong Fang LiuAbstract:Abstract In the near neutral media, sodium carboxymethylcellulose (NaCMC) can react with a cationic Acridine Dyes such as Acridine yellow (AY) and Acridine orange (AO) to form an ion-association complex. As results of the reaction, intensity of resonance Rayleigh scattering (RRS) is enhanced greatly and new RRS spectra appeared. The maximum scattering peaks exist at 285 nm for AY–CMC and 315 nm for AO–CMC. There is linear relationship between the relative intensity of RRS (Δ I ) and concentration of NaCMC in the range of 0–1.5 μg ml −1 for AY system and 0–3.0 μg ml −1 for AO system. The method for determination of NaCMC has high sensitivity. The detection limits (3 σ ) are 6.0 ng ml −1 for AY and 41.7 ng ml −1 for AO. Moreover, effects of foreign substances on determination of NaCMC have been investigated. It shows that the methods have good selectivity. A new method for the determination of NaCMC with AY or AO by RRS technique has been proposed. The method is sensitive, simple and fast.
