Consideration on the Metachromatic Spectra of Toluidine Blue Dimers Formed on DNA Oligomers
25 Sep 2010-Bulletin of the Chemical Society of Japan (Chemical Society of Japan)-Vol. 83, Iss: 10, pp 1216-1222
TL;DR: The results suggest that the metachromati cc olor observed during biological staining is ignificantly affected by the helical geometry of DNA.
Abstract: Metachromatic staining with toluidine blue (TB) has been used as a cytological too lf or tissue recognition and cancer diagnosis. Recently, its strong potentia lf or infertility diagnosis was also reported. Metachromatic staining is important i nb iological applications, but the origi no f spectral changes has not been fully understood, although dye aggregation on biological materials is thought to be the cause. In this study, we investigated the dimer structure of TB formed on DNA oligomers by using a computational method, particularly focusing on the spectral changes caused by TB dimer formation. The structure of the TBDNA complexes was constructed on the basi so f the calculated molecular structure of TB and crystal data of A- and B-form DNA oligomers, assuming that there was an electrostatic interaction between them. The resulting spectral shift was then evaluated using the extended-dipole model. The examination of B-DNA revealed that possibl eT B dimers result in a hypsochromic spectral shif to f absorption. On the other hand, the dimerization of TB on A-DNA was found to be quite difficult, because the helical geometry of A-DNA restricted the binding sites of TB. These results suggest that the metachromati cc olor observed during biological staining i ss ignificantly affected by the helical geometry of DNA.
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TL;DR: In this paper, a new eco-friendly, selective and sensitive method was developed for preconcentration and determination of trace levels of sulfite by ultrasonic-assisted cloud point extraction (UA-CPE).
Abstract: A new eco-friendly, selective and sensitive method was developed for preconcentration and determination of trace levels of sulfite by ultrasonic-assisted cloud point extraction (UA-CPE). The method is based on the selective ion-association of the anionic complex, Cu(SO3)22−, produced depending on sulfite concentration in the presence of excess Cu(II) ions with toluidine blue (TB+) at pH 7.5, and then extraction of the formed ion-associate complex into the surfactant rich phase of Triton X-45 micelles. Under the optimized reagent conditions, the calibration curve is linear in range of 2.5–350 μg L−1, and the limits of detection and quantification of the method (LOD and LOQ) (3σblank/m and 10σblank/m) are 1.15 and 3.82 μg L−1 with a sensitivity enhancement factor of 95. The results demonstrated that the method achieved acceptable quantitative recoveries of 95.7–102.9% with relative standard deviations (RSDs) of 2.1–4.8%. The method showed good selectivity, and was successfully applied to the quantification of sulfite species in vegetable and dried fruit samples with satisfactory results. The results were compared with those of the standard 5,5′-dithio-bis(2-nitrobenzoic acid) (DTNB) method, and the two paired t-test was used to determine whether the results obtained by the two methods differ significantly.
35 citations
TL;DR: A physicochemical study of COS varying in degree of polymerization (DP) from 5 to 50 is proposed, both from the point of view of the solution properties and the complexing behavior with siRNA.
Abstract: In the context of gene delivery, chitosan has been widely used as a safe and effective polycation to complex DNA, RNA and more recently, siRNA. However, much less attention has been paid to chitosan oligosaccharides (COS) despite their biological properties. This study proposed to carry out a physicochemical study of COS varying in degree of polymerization (DP) from 5 to 50, both from the point of view of the solution properties and the complexing behavior with siRNA. The main parameters studied as a function of DP were the apparent pKa, the solubility versus pH, the binding affinity with siRNA and the colloidal properties of complexes. Some parameters, like the pKa or the binding enthalpy with siRNA, showed a marked transition from DP 5 to DP 13, suggesting that electrostatic properties of COS vary considerably in this range of DP. The colloidal properties of siRNA/COS complexes were affected in a different way by the COS chain length. In particular, COS of relatively high DP (≥50) were required to form small complex particles with good stability.
17 citations
Cites background from "Consideration on the Metachromatic ..."
...The TB is a positively charged dye that can interact with phosphate groups of siRNA through electrostatic interaction [57]....
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TL;DR: Together these data suggest that certain epichromatin segments assume the relatively hydrophobic DNA A-conformation at the nuclear envelope and surface of mitotic chromosomes, preventing AO side dimerisation.
Abstract: The chromatin observed by conventional electron microscopy under the nuclear envelope constitutes a single layer of dense 30–35 nm granules, while ∼30 nm fibrils laterally attached to them, form large patches of lamin-associated domains (LADs). This particular surface “epichromatin” can be discerned by specific (H2A+H2B+DNA) conformational antibody at the inner nuclear envelope and around mitotic chromosomes. In order to differentiate the DNA conformation of the peripheral chromatin we applied an Acridine orange (AO) DNA structural test involving RNAse treatment and the addition of AO after acid pre-treatment. MCF-7 cells treated in this way revealed yellow/red patches of LADs attached to a thin green nuclear rim and with mitotic chromosomes outlined in green, topologically corresponding to epichromatin epitope staining by immunofluorescence. Differentially from LADs, the epichromatin was unable to provide metachromatic staining by AO, unless thermally denatured at 94oC. DNA enrichment in GC stret...
10 citations
Cites background from "Consideration on the Metachromatic ..."
...The ability to bind cationic dimethyl-amino residues of the aromatic stain toluidine blue by two neighbour phosphate residues of the DNA backbone in the A-form helix was found improbable due to its too narrow minor groove [40]....
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TL;DR: In this paper, the anionic binding sites of the sulfated polysaccharides (SPS) and the TB-SPS interaction were analyzed using a single fit curve.
Abstract: Isothermal microtitration calorimetry was performed to analyze the interaction of fucoidan and dextran sulfate with toluidine blue O (TB) to achieve relevant and characteristic thermodynamic information. Thermodynamic data obtained were referred to the anionic binding sites of the sulfated polysaccharides (SPS) and were not related to the polysaccharide concentration in general. Enthalpic values achieved by the two SPS titrations in TB solutions could be approximated using a single fit curve. The same also applies for the TB titrations in SPS solutions. Evaluation of the data obtained for forward and reverse titrations could not be performed since it results in inconsistent enthalpic and entropic contributions. An appropriate modeling could only be performed assuming two non-symmetric binding sites at the SPS although the thermodynamic data revealed a 1:1 stoichiometry. A 1:2 model accounts for the deviation generated by the stacking of the TB molecules. Data obtained for the binding of a single TB to a sulfate ester indicate highly negative values (−9.7 to −9.4 kcal mol−1) for the change in Gibbs energy and thus a spontaneous enthalpy-driven reaction. Formally, further thermodynamic values contain information about the second binding site at SPS. In this case, the information provided can be equated with the TB–TB interaction or dimerization that is entropically favored (T∆S = 13.7–16.5 kcal mol−1). Equilibrium constant for TB binding at the sulfate esters values to 0.7–1.4 10−7 mol−1, and TB–TB interaction has a binding constant of 2.1–3.0 10−4 mol−1, indicating an equilibrium which is mainly positioned at the dimers.
5 citations
Cites background from "Consideration on the Metachromatic ..."
...Based on this, dyes should be ordered in aggregates along the longitudinal axis of the polymer [6]....
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TL;DR: It is suggested that sugammadex may have an inhibitory effect on mobilization and morphological changes in pancreatic mast cells induced by administration of rocuronium and sugamadex in rats.
Abstract: Mast cells play a vital role in hypersensitivity reactions. Rocuronium is known to cause mast cell mobilization, hypersensitivity, and pancreatitis. The aim of this study was to investigate the effects of sugammadex on pancreatic changes due to rocuronium. A total of 42 Sprague-Dawley male rats were divided into six equal groups to receive either rocuronium 1 mg/kg intravenously (i.v., R group), rocuronium 1 mg/kg + sugammadex 16 mg/kg i.v. (RS16 group), rocuronium 1 mg/kg + sugammadex 96 mg/kg i.v. (RS96 group), sugammadex 16 mg/kg (S16), sugammadex 96 mg/kg i.v. (S96 group), or 0.9% sodium chloride (control group). Sugammadex was administered 5s later following rocuronium. In R group, mast count was higher, and the distribution rate of granules and nuclear changes were different compared with other groups. Distribution rate of granules in groups S16 and S96 were similar to the control group and lower compared with other groups. The amount of mast cells and granule density in groups RS16 and RS96 was lower compared with R group. The amount of mast cells in groups RS16 and RS96 was significantly lower compared with other treatment groups. These results suggest that sugammadex may have an inhibitory effect on mobilization and morphological changes in pancreatic mast cells induced by administration of rocuronium and sugammadex in rats.
4 citations
Cites background from "Consideration on the Metachromatic ..."
...Metachromatic staining is very important in biological applications, such as tissue recognition (Sato et al., 2010)....
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References
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TL;DR: In this paper, a new parametric quantum mechanical molecular model, AM1 (Austin Model l), based on the NDDO approximation, is described, in which the major weaknesses of MNDO, in particular failure to reproduce hydrogen bonds, have been overcome without any increase in computing time.
Abstract: A new parametric quantum mechanical molecular model, AM1 (Austin Model l), based on the NDDO approximation, is described. In it the major weaknesses of MNDO, in particular failure to reproduce hydrogen bonds, have been overcome without any increase in computing time. Results for 167 molecules are reported. Parameters are currently available for C, H, 0, and N.
12,452 citations
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TL;DR: A simple model for the calculation of interaction integrals between dye molecules in aggregates is shown to be in excellent agreement with the result of quantum-mechanical computations even at direct contact of the molecules.
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TL;DR: The collective data provide new structural details on the conformational pathway connecting A and B-form DNA and illustrate how both proteins and drugs take advantage of the intrinsic conformational mechanics of the double helix.
319 citations