scholarly journals STAINING OF TISSUE POLYCATIONS BY ANIONIC DYES IN SALT SOLUTIONS WITH SPECIAL REFERENCE TO GINGIVA

1970 ◽  
Vol 18 (6) ◽  
pp. 424-438 ◽  
Author(s):  
P. H. STAPLE
Keyword(s):  
Alcian Blue ◽  
Choline Chloride ◽  
Reaction Medium ◽  
Limited Range ◽  
Cervical Region ◽  
Acid Fuchsin ◽  
Salt Solutions ◽  
Anionic Dyes ◽  
Horizontal Section ◽  
Reactive Material

Over the range pH 5.6-9.4, the presence of KCl or other common metallic chlorides in excess of 0.1 M in 0.05% solutions of Biebrich scarlet or acid fuchsin produced a colored precipitate within 24 hr. Within the same period, over the range pH 2-7, no precipitate resulted when up to 5 M choline chloride (highest concentration tested) was present in 0.01% solutions of these and other anionic dyes used for staining tissue sections. In paraffin sections of frozen-dried tissues, previously exposed to modified Newcomer's fluid or cyanuric chloride in anhydrous reaction medium, equilibrium staining in the presence of increasing concentrations of choline chloride or potassium chloride was investigated at pH 2.28-2.70, 5.6 and 6.18-6.70 using 0.01% or 0.001% solutions of acid fuchsin, Biebrich scarlet or its isomer crocein scarlet, fast green FCF, naphthol yellow S. The tissues studied were: prevertebral structures included in a horizontal section through the cervical region of a mouse, rat abdominal skin and gingiva, human gingiva. In general, increasing salt concentration progressively inhibited staining, but over a limited range could increase staining, e. g., in cartilage, by unmasking additional dye-binding groups through the dissociation of macromolecular polyionic complexes. Sequential staining with the same or two different dyes in presence of different salt concentrations showed that inhibition of straining by salt was not due to elution of reactive material from sections but to competition between salt and dye anions for cationic sites in tissues. The biologic polyanions heparinate and hyaluronate were found to compete with Biebrich scarlet for tissue cationic sites. The concept of critical electrolyte concentration (CEC) proposed for staining with cationic dyes in salt solutions was found to be applicable to staining with anionic dyes and thus to be generally valid for staining that involves polar interactions. Rat gingival keratin, previously shown to have only a low CEC for the cationic dye Alcian Blue, displayed a high CEC for all of the anionic dyes investigated. Some sites in mouse arterial wall and laryngeal cartilage known to have a high CEC for Alcian Blue showed high CEC for Biebrich scarlet. It is suggested that the high CEC of human gingival parakeratin for anionic dyes depends on the presence of arginine, histidine and lysine protein residues and those few α-amino groups capable of protonation.

Rapid Synthesis of Primary Amines from Ketones using Choline Chloride/Urea Deep Eutectic as a Reaction Medium

2021 ◽  
pp. 1-7
Author(s):  
Cleverton de S. Fernandes ◽  
Camila B. Francisco ◽  
Gisele de F. Gauze ◽  
Roberto Rittner ◽  
Ernani A. Basso
Keyword(s):  
Choline Chloride ◽  
Reaction Medium ◽  
Primary Amines ◽  
Rapid Synthesis

EFFECTS OF DILUTED NATURAL WATER AND ALTERED IONIC ENVIRONMENTS ON GUSTATORY RESPONSES IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

1994 ◽  
Vol 186 (1) ◽  
pp. 173-186
Author(s):  
Y. Kitada ◽  
T. Hara
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Natural Water ◽  
Essential Role ◽  
Apical Membrane ◽  
Choline Chloride ◽  
Salt Solutions ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Major Cations ◽  
Unknown Substance

1. The effects of adaptation to diluted natural water (NW) and various salt solutions on the gustatory responses recorded from the palatine nerve in rainbow trout (Oncorhynchus mykiss) were studied. 2. The magnitude of the response to 1 mmol l-1 l-proline (l-Pro) decreased when the perfusing NW was diluted with artificial fresh water (AFW) that maintained concentrations of major cations. AFW suppressed the responses to l-Pro by about 70 %. 3. The responses to 1 mmol l-1 l-Pro, 0.1 mmol l-1 quinine­HCl (Q-HCl) and 10 nmol l-1 taurolithocholic acid (TLCA) were eliminated or reduced (to <10 %) by adapting the palate to distilled water (DW). The addition of 0.1–100 mmol l-1 salts (NaCl, KCl, CaCl2, MgCl2) and choline chloride restored the gustatory responses to about 50 % of those in NW. The addition of salts to NW had no effect on the gustatory responses. 4. The gustatory responses to 5 % CO2 were similarly reduced when the palate was adapted to solutions that contained no NW (DW, AFW, 10 mmol l-1 NaCl in DW). However, the reduction was independent of salt concentration, suggesting a different transduction mechanism for CO2. 4. Tetrodotoxin (1 µmol l-1) had no effect on the gustatory responses to l-Pro. 5. We conclude that NW is required and that cations alone are not sufficient to support maximal gustatory responses. The results suggest that an unknown substance(s) contained in NW plays an essential role in gustatory reception and that permeation of cations through the apical membrane of gustatory cells is not involved in gustatory transduction in rainbow trout.

The partitioning of exchangeable magnesium, calcium and sodium in relation to their effects on the dispersion of Australian clay subsoils

Soil Research ◽  
1985 ◽  
Vol 23 (3) ◽  
pp. 405 ◽  
Author(s):  
BM Tucker
Keyword(s):  
Organic Matter ◽  
Ammonium Sulfate ◽  
Analytical Methods ◽  
Deleterious Effect ◽  
Choline Chloride ◽  
Soil Samples ◽  
Exchangeable Cations ◽  
Salt Solutions ◽  
Exchangeable Magnesium ◽  
Chloride Method

Clay subsoils were analysed by a procedure that uses a choline chloride reagent to distinguish double-layer exchangeable cations from other more strongly adsorbed forms extractable by an ammonium sulfate reagent. In those clay subsoils that contained little organic matter, the exchangeable cations made up nearly all of the cations that reacted with salt solutions. This means that it makes no practical difference to values of Ca/Mg ratios, or of ESP, whether the analytical methods discriminate between those exchangeable cations and other adsorbed cations, or do not, provided the soil samples contain little organic matter. The adoption of the new choline chloride method will not make necessary any revision of the criteria already in use in Australia for sodium- or magnesium-affected subsoils. Some possible mechanisms for the deleterious effect that large amounts of exchangeable magnesium have on the properties of subsoil clays containing illite are discussed. It is shown that the single-charged cations MgCl+ or MgOH+ are not involved. The clays hold exchangeable magnesium slightly less strongly than they hold calcium, and this weaker binding remains the best explanation for the magnesium effect.

scholarly journals Reactive Deep Eutectic Solvents (RDESs): A New Tool for Phospholipase D-Catalyzed Preparation of Phospholipids

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 655
Author(s):  
Chiara Allegretti ◽  
Francesco G. Gatti ◽  
Stefano Marzorati ◽  
Letizia Anna Maria Rossato ◽  
Stefano Serra ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ethylene Glycol ◽  
Phospholipase D ◽  
Choline Chloride ◽  
Reaction Medium ◽  
Deep Eutectic Solvents ◽  
Polar Head ◽  
Process Implementation ◽  
Reaction Media ◽  
Hydrogen Bond Donors

The use of Reactive Deep Eutectic Solvents (RDESs) in the preparation of polar head modified phospholipids (PLs) with phospholipase D (PLD)-catalyzed biotransformations has been investigated. Natural phosphatidylcholine (PC) has been submitted to PLD-catalyzed transphosphatidylations using a new reaction medium composed by a mixture of RDES/buffer. Instead of exploiting deep eutectic solvents conventionally, just as the reaction media, these solvents have been designed here in order to contribute actively to the synthetic processes by participating as reagents. RDESs were prepared using choline chloride or trimethyl glycine as hydrogen-bond acceptors and glycerol or ethylene glycol, as hydrogen-bond donors as well as nucleophiles for choline substitution. Specifically designed RDES/buffer reaction media allowed the obtainment of PLs with optimized yields in the perspective of a sustainable process implementation.

Deep eutectic solvent: a green and sustainable alternative for the synthesis of copper phthalocyanine blue and its value added applications

2020 ◽  
Vol 49 (4) ◽  
pp. 325-330
Author(s):  
Amruta Joglekar-Athavale ◽  
Ganapti S. Shankarling
Keyword(s):  
Copper Phthalocyanine ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Reaction Medium ◽  
Value Added ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Content Type ◽  
Commercially Important ◽  
Screen Ink

Purpose This paper aims to propose a simple, effective and environmentally benign method for the synthesis of commercially important pigment copper phthalocyanine (PC) blue has been developed using deep eutectic solvent (DES). Design/methodology/approach DES prepared from choline chloride and urea is used as a reaction medium, as well as a source of ammonia. The design of the experiment and factorial design study has proved that the milder reaction conditions with high yields and reusability of DES are the key features of the present study. Findings The synthesized pigment is obtained at milder reaction conditions with excellent yield, which can be seen from the design of experiments done for the optimization of results. Practical implications The synthesized pigment was used as a colorant in epoxy-based paint and in screen ink, which gave satisfactory results with respect to color values and stability. Social implications The screen ink prepared was formulated considering environmental aspects to avoid the use of solvents. Biodegradable components were added to the colorant to make the ink environment friendly. Originality/value Reactions occur at moderate temperatures without affecting the time factor, thus, it saves energy. A simple, effective and environmentally benign method for the synthesis of commercially important copper PC has been developed using DES. After the first batch, DES synthesized can be reused as a reaction medium where only a stoichiometric amount of urea is to be added. Simple work up, high yield and purity are achieved.

Choline Chloride/Glycerol Promoted Synthesis of 3,3-Disubstituted Indol-2-ones

2021 ◽  
Vol 07 ◽  
Author(s):  
Ling Xu ◽  
Wei-Hong Zhang ◽  
Zhen-Shui Cui ◽  
Zhan-Hui Zhang
Keyword(s):  
Microwave Irradiation ◽  
Condensation Reaction ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Reaction Medium ◽  
Practical Method ◽  
Model Reaction ◽  
Environmentally Sustainable ◽  
High Yields ◽  
Natural Deep Eutectic Solvent

Objective: 3,3-Disubstituted indol-2-one derivatives have wider applications in pharmaceuticals and they are key intermediates for the synthesis of many kinds of drug candidates. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of views. Methods: In order to establish an effective synthetic method for preparing 3,3-disubstituted indol-2-one derivatives, the bis-condensation reaction of isatin and 1H-indene-1,3(2H)-dione was selected as a model reaction. A variety of natural deep eutectic solvent (NADES) were prepared and used for this reaction. The generality and limitation of the established method were also investigated. Results: It was found that model reaction can be carried out in natural deep eutectic solvent (NADES) based on choline chloride (ChCl) at 80 oC under microwave irradiation. This protocol with a broad substrate applicability afforded various 2,2'-(2-oxoindoline-3,3-diyl)bis(1H-indene-1,3(2H)-dione) derivatives in high yields. Conclusion: simple and efficient procedure has been developed for synthesis of 2,2'-(2-oxoindoline-3,3-diyl)bis(1H-indene-1,3(2H)-dione), spiro[indoline-3,7'-pyrano[5,6-c:5,6-c']dichromene]-2,6',8'-trione, and spiro[indoline-3,9'-xan-thene] trione via bis-condensation between isatin with 1,3-indandione, 4-hydroxycoumarin or 1,3-cyclohexanedione in nat-ural deep eutectic solvent (NADES) based on choline chloride (ChCl) and glycerol (Gl) under microwave irradiation. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvent, clean reaction profiles, non-chromatographic purification procedure, and high to excellent yield. Furthermore, the use of NADES as green reaction medium reduces burden on environment and makes the present method environmentally sustainable.

scholarly journals Increased Selectivity of Novozym 435 in the Asymmetric Hydrolysis of a Substrate with High Hydrophobicity Through the Use of Deep Eutectic Solvents and High Substrate Concentrations

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 792 ◽  
Author(s):  
Yerko Fredes ◽  
Lesly Chamorro ◽  
Zaida Cabrera
Keyword(s):  
Substrate Concentration ◽  
Phosphate Buffer ◽  
Choline Chloride ◽  
Reaction Medium ◽  
Deep Eutectic Solvents ◽  
Novozym 435 ◽  
Chiral Drugs ◽  
High Substrate ◽  
Hydrolysis Of ◽  
Substrate Concentrations

The effects of the reaction medium and substrate concentration were studied on the selectivity of Novozym 435 using the asymmetric hydrolysis of dimethyl-3-phenylglutarate as a model reaction. Results show that the use of choline chloride ChCl:urea/phosphate buffer 50% (v/v) as a reaction medium increased the selectivity of Novozym 435 by 16% (e.e = 88%) with respect to the one in 100% phosphate buffer (e.e = 76%). Best results were obtained when high substrate concentrations (well above the solubility limit, 27-fold) and ChCl:urea/phosphate buffer 50% (v/v) as reaction medium at pH 7 and 30 °C were used. Under such conditions, the R-monoester was produced with an enantiomeric purity of 99%. Novozym 435 was more stable in ChCl:urea/phosphate buffer 50% (v/v) than in phosphate buffer, retaining a 50% of its initial activity after 27 h of incubation at pH 7 and 40 °C. Results suggest that the use of deep eutectic solvents (ChCl:urea/phosphate buffer) in an heterogeneous reaction system (high substrate concentration) is a viable and promising strategy for the synthesis of chiral drugs from highly hydrophobic substrates.

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