Non-covalent binding and selective fluorescent sensing of dipyrone with a carbocyanine dye and cetyltrimethylammonium bromide

Author(s):  
Sofia A. Zakharenkova ◽  
Anna S. Kriveleva ◽  
Ekaterina A. Katkova ◽  
Irina A Doroshenko ◽  
Nikolai Yu. Polovkov ◽  
...  
Author(s):  
Linda C. Hassinger ◽  
James E. Crandall

We have begun to look directly at small numbers of afferent axons to early generated neurons that form the preplate in the developing mouse cortex. The carbocyanine dye Dil (1’1, dioctadecyl-3,3,3’3’-tetramethyl-indocarbocyanine) has proved especially useful for this goal. DiI labels axons and their terminals with greater sensitivity and without some of the disadvantages of axon filling with HRP. The increased sensitivity provided by labeling embryonic axons with DiI has given us new insights into the development of cortical afferents. For instance, we reported originally that afferents from the thalamus were present below the cortex as early as embryonic day 15 (E15) based on HRP injections into mouse embryos. By using DiI placements into the thalamus in aldehyde-fixed brains, we now know that thalamic fibers reach the cortex 24 hrs earlier.


Author(s):  
Wm. J. Arnold ◽  
J. Russo ◽  
H. D. Soule ◽  
M. A. Rich

Our studies of mammary tumor virus have included the application of the unlabeled antibody enzyme method of Sternberger to mammary tumor derived mouse cells in culture and observation with an electron microscope. The method avoids the extravagance of covalent binding of indicator molecules (horseradish peroxidase) with precious antibody locator molecules by relying instead upon specific antibody-antigen linkages. Our reagents included: Primary Antibody, rabbit anti-murine mammary tumor virus (MuMTV) which was antiserum 113 AV-2; Secondary Antibody, goat anti-rabbit IgG gamma chain (Cappel Laboratories); andthe Indicator, rabbit anti-horseradish peroxidase - horseradish peroxidase complex (PAP) (Cappel Labs.). Dilutions and washes were made in 0.05 M Tris 0.15 M saline buffered to pH 7.4. Cell monolayers, after light fixation in glutaraldehyde, were incubated in place by a protocol adapted from Sternberger and Graham and Karnovsky, then embedded by our usual method for monolayers. Reagents were confined to specific areas by neoprene 0-rings (Parker Seal Co.) reducing the amount of reagent needed to 50 microliters, 1/6th of that required to wet a 35 mm petri dish.


2019 ◽  
Vol 64 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Elias S.J. Arnér

Abstract Selenocysteine (Sec), the sulfur-to-selenium substituted variant of cysteine (Cys), is the defining entity of selenoproteins. These are naturally expressed in many diverse organisms and constitute a unique class of proteins. As a result of the physicochemical characteristics of selenium when compared with sulfur, Sec is typically more reactive than Cys while participating in similar reactions, and there are also some qualitative differences in the reactivities between the two amino acids. This minireview discusses the types of modifications of Sec in selenoproteins that have thus far been experimentally validated. These modifications include direct covalent binding through the Se atom of Sec to other chalcogen atoms (S, O and Se) as present in redox active molecular motifs, derivatization of Sec via the direct covalent binding to non-chalcogen elements (Ni, Mb, N, Au and C), and the loss of Se from Sec resulting in formation of dehydroalanine. To understand the nature of these Sec modifications is crucial for an understanding of selenoprotein reactivities in biological, physiological and pathophysiological contexts.


2000 ◽  
Vol 628 ◽  
Author(s):  
Sophie Besson ◽  
Catherine Jacquiod ◽  
Thierry Gacoin ◽  
André Naudon ◽  
Christian Ricolleau ◽  
...  

ABSTRACTA microstructural study on surfactant templated silica films is performed by coupling traditional X-Ray Diffraction (XRD) and Transmission Electronic Microscopy (TEM) to Grazing Incidence Small Angle X-Ray Scattering (GISAXS). By this method it is shown that spin-coating of silicate solutions with cationic surfactant cetyltrimethylammonium bromide (CTAB) as a templating agent provides 3D hexagonal structure (space group P63/mmc) that is no longer compatible with the often described hexagonal arrangement of tubular micelles but rather with an hexagonal arrangement of spherical micelles. The extent of the hexagonal ordering and the texture can be optimized in films by varying the composition of the solution.


2018 ◽  
Author(s):  
Jiajun Wang ◽  
Jayesh Arun Bafna ◽  
Satya Prathyusha Bhamidimarri ◽  
Mathias Winterhalter

Biological channels facilitate the exchange of small molecules across membranes, but surprisingly there is a lack of general tools for the identification and quantification of transport (i.e., translocation and binding). Analyzing the ion current fluctuation of a typical channel with its constriction region in the middle does not allow a direct conclusion on successful transport. For this, we created an additional barrier acting as a molecular counter at the exit of the channel. To identify permeation, we mainly read the molecule residence time in the channel lumen as the indicator whether the molecule reached the exit of the channel. As an example, here we use the well-studied porin, OmpF, an outer membrane channel from <i>E. coli</i>. Inspection of the channel structure suggests that aspartic acid at position 181 is located below the constriction region (CR) and we subsequently mutated this residue to cysteine, where else cysteine free and functionalized it by covalent binding with 2-sulfonatoethyl methanethiosulfonate (MTSES) or the larger glutathione (GLT) blockers. Using the dwell time as the signal for transport, we found that both mono-arginine and tri-arginine permeation process is prolonged by 20% and 50% respectively through OmpF<sub>E181C</sub>MTSES, while the larger sized blocker modification OmpF<sub>E181C</sub>GLT drastically decreased the permeation of mono-arginine by 9-fold and even blocked the pathway of the tri-arginine. In case of the hepta-arginine as substrate, both chemical modifications led to an identical ‘blocked’ pattern observed by the dwell time of ion current fluctuation of the OmpF<sub>wt</sub>. As an instance for antibiotic permeation, we analyzed norfloxacin, a fluoroquinolone antimicrobial agent. The modulation of the interaction dwell time suggests possible successful permeation of norfloxacin across OmpF<sub>wt</sub>. This approach may discriminate blockages from translocation events for a wide range of substrates. A potential application could be screening for scaffolds to improve the permeability of antibiotics.


2020 ◽  
Vol 21 (9) ◽  
pp. 846-859
Author(s):  
Mohd Saeed ◽  
Mohd Adnan Kausar ◽  
Rajeev Singh ◽  
Arif J. Siddiqui ◽  
Asma Akhter

Glycation refers to the covalent binding of sugar molecules to macromolecules, such as DNA, proteins, and lipids in a non-enzymatic reaction, resulting in the formation of irreversibly bound products known as advanced glycation end products (AGEs). AGEs are synthesized in high amounts both in pathological conditions, such as diabetes and under physiological conditions resulting in aging. The body’s anti-glycation defense mechanisms play a critical role in removing glycated products. However, if this defense system fails, AGEs start accumulating, which results in pathological conditions. Studies have been shown that increased accumulation of AGEs acts as key mediators in multiple diseases, such as diabetes, obesity, arthritis, cancer, atherosclerosis, decreased skin elasticity, male erectile dysfunction, pulmonary fibrosis, aging, and Alzheimer’s disease. Furthermore, glycation of nucleotides, proteins, and phospholipids by α-oxoaldehyde metabolites, such as glyoxal (GO) and methylglyoxal (MGO), causes potential damage to the genome, proteome, and lipidome. Glyoxalase-1 (GLO-1) acts as a part of the anti-glycation defense system by carrying out detoxification of GO and MGO. It has been demonstrated that GLO-1 protects dicarbonyl modifications of the proteome and lipidome, thereby impeding the cell signaling and affecting age-related diseases. Its relationship with detoxification and anti-glycation defense is well established. Glycation of proteins by MGO and GO results in protein misfolding, thereby affecting their structure and function. These findings provide evidence for the rationale that the functional modulation of the GLO pathway could be used as a potential therapeutic target. In the present review, we summarized the newly emerged literature on the GLO pathway, including enzymes regulating the process. In addition, we described small bioactive molecules with the potential to modulate the GLO pathway, thereby providing a basis for the development of new treatment strategies against age-related complications.


2020 ◽  
Vol 20 (23) ◽  
pp. 2106-2117
Author(s):  
Martin Krátký ◽  
Šárka Štěpánková ◽  
Michaela Brablíková ◽  
Katarína Svrčková ◽  
Markéta Švarcová ◽  
...  

Background: Hydrazide-hydrazones have been known as scaffold with various biological activities including inhibition of acetyl- (AChE) and butyrylcholinesterase (BuChE). Cholinesterase inhibitors are mainstays of dementias’ treatment. Objective: Twenty-five iodinated hydrazide-hydrazones and their analogues were designed as potential central AChE and BuChE inhibitors. Methods: Hydrazide-hydrazones were synthesized from 4-substituted benzohydrazides and 2-/4- hydroxy-3,5-diiodobenzaldehydes. The compounds were investigated in vitro for their potency to inhibit AChE from electric eel and BuChE from equine serum using Ellman’s method. We calculated also physicochemical and structural parameters for CNS delivery. Results: The derivatives exhibited a moderate dual inhibition with IC50 values ranging from 15.1-140.5 and 35.5 to 170.5 μmol.L-1 for AChE and BuChE, respectively. Generally, the compounds produced a balanced or more potent inhibition of AChE. N'-[(E)-(4-Hydroxy-3,5-diiodophenyl)methylidene]-4- nitrobenzohydrazide 2k and 4-fluoro-N'-(2-hydroxy-3,5-diiodobenzyl)benzohydrazide 3a were the most potent inhibitors of AChE and BuChE, respectively. Structure-activity relationships were established, and molecular docking studies confirmed interaction with enzymes. Conclusion: Many novel hydrazide-hydrazones showed lower IC50 values than rivastigmine against AChE and some of them were comparable for BuChE to this drug used for the treatment of dementia. They interact with cholinesterases via non-covalent binding into the active site. Based on the BOILEDEgg approach, the majority of the derivatives met the criteria for blood-brain-barrier permeability.


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