Étude comparée de trois antibiotiques ionophores: X.537 A (lasalocide), A.23187 (calcimycine) et X.14547 A. Complexation des cations IA et IIA, transport de Ca++

1982 ◽  
Vol 60 (8) ◽  
pp. 981-989 ◽  
Author(s):  
Jean Bolte ◽  
Colette Demuynck ◽  
Georges Jeminet ◽  
Jean Juillard ◽  
Claude Tissier
Keyword(s):  
Aqueous Phase ◽  
Alkaline Earth ◽  
Equilibrium Constants ◽  
Alkali Metal Ions ◽  
A 23187 ◽  
Ionic Fluxes ◽  
Stability Of Complexes ◽  
A Cell ◽  
The Stability ◽  
Alkaline Earth Cations

Using a potentiometric method, both the stoechiometry and the stability of complexes formed in methanol between the three natural ionophores and cations IA and IIA have been obtained. With alkali metal ions, neutral complexes of stoechiometry 1:1 for X.537 A and A.23187, 2:1 for X.14547 A are formed. Complexes of higher stability are obtained with alkaline-earth cations, corresponding to two types of association; 1:1 charged and 2:1 neutral. A.23187 and X.14547 A show similar behaviour as far as the sequence of formation of these two complexes is concerned, but the stability constants are higher for the first one. For X.537 A, the existence of a 2:1 complex is not detectable by our method, except for magnesium.Calcium transport by these ionophores through a cell such as: aqueous phase/chloroformic phase/aqueous phase has also been studied. An attempt is made to relate ionic fluxes to the preceding equilibrium constants.

scholarly journals Ionisation potential and electron affinity of free 5′,8-cyclopurine-2′-deoxynucleosides. DFT study in gaseous and aqueous phase

2010 ◽  
Vol 8 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Boleslaw Karwowski
Keyword(s):  
Ionization Potential ◽  
Aqueous Phase ◽  
Electron Affinity ◽  
Density Functional ◽  
Zero Point ◽  
Basis Set ◽  
A Cell ◽  
Vertical Detachment Energy ◽  
Vertical Electron Affinity ◽  
The Stability

AbstractOxidatively generated damage to DNA frequently appears in the human genome as an effect of aerobic metabolism or as the result of exposure to exogenous oxidizing agents. Due to these facts it was decided to present, for the first time, the electron affinity, ionization potential of 5′,8-cyclo-2′-deoxyadenosine/guanosine (cdA, cdG) in their 5′R and 5′S diastereomeric forms. For all points of quantum mechanics studies presented, the density functional theory (DFT) with B3LYP parameters on 6-311++G** basis set level was used. The zero-point vibrational corrected adiabatic electron affinity (AEA) and adiabatic ionization potential (AIP) were calculated. Additionally the vertical electron affinity (VEA), vertical detachment energy (VDE) and vertical ionization potential were taken into consideration. AEA in eV (gaseous/aqueous phase) are as follows: 0.3/1.81 (5′R)cdA, 0.13/1.76 (5′S)cdA, 0.17/1.49 (5′R)cdG, 0.14/1.53 (5′S)cdG and AIP followed the order 7.43/5.59(5′S)cdG, 7.49/5.60(5′R)cdG, 7.77/5.97(5′R)cdA, 7.84/5.93(5′S)cdA. The obtained AIPs were found to be lower than that for corresponding natural nucleosides. Therefore, even though the 5′,8-cyclopurine-2′-deoxynucleoside level in a cell was judged as low, they can play an important role in the stability, replication and transcription of genes.

The stability of complexes of alkali and alkaline earth ions with crown ether carboxylic acids

Polyhedron ◽  
1991 ◽  
Vol 10 (13) ◽  
pp. 1591-1592 ◽  
Author(s):  
Heinz Bukowsky ◽  
Erhard Uhlemann ◽  
Karsten Gloe ◽  
Petern Mühl
Keyword(s):  
Crown Ether ◽  
Carboxylic Acids ◽  
Alkaline Earth ◽  
Stability Of Complexes ◽  
The Stability

Using FRET to Measure the Time it Takes for a Cell to Destroy a Virus

2019 ◽  
Author(s):  
Candace E. Benjamin ◽  
Zhuo Chen ◽  
Olivia Brohlin ◽  
Hamilton Lee ◽  
Stefanie Boyd ◽  
...  
Keyword(s):  
Cellular Uptake ◽  
Rhodamine B ◽  
Virus Like Particle ◽  
A Cell ◽  
Viral Nanoparticles ◽  
The Stability ◽  
Open Question ◽  
Viral Surface ◽  
Fret Pair

<div><div><div><p>The emergence of viral nanotechnology over the preceding two decades has created a number of intellectually captivating possible translational applications; however, the in vitro fate of the viral nanoparticles in cells remains an open question. Herein, we investigate the stability and lifetime of virus-like particle (VLP) Qβ - a representative and popular VLP for several applications - following cellular uptake. By exploiting the available functional handles on the viral surface, we have orthogonally installed the known FRET pair, FITC and Rhodamine B, to gain insight of the particle’s behavior in vitro. Based on these data, we believe VLPs undergo aggregation in addition to the anticipated proteolysis within a few hours of cellular uptake.</p></div></div></div>

Impact of Alkaline Earth Metal Doping on the Stability of Perovskite Solar Cells

2019 ◽  
Author(s):  
Nga Phung ◽  
Hans Köbler ◽  
Diego Di Girolamo ◽  
Thi Tuyen Ngo ◽  
Gabrielle Sousa e Silva ◽  
...  
Keyword(s):  
Solar Cells ◽  
Alkaline Earth ◽  
Perovskite Solar Cells ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Metal Doping ◽  
The Stability

Extraction of strontium and barium salts by the nitrobenzene solution of dicarbolide in the presence of glymes

1985 ◽  
Vol 50 (3) ◽  
pp. 581-599 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Stability Constants ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Minor Role ◽  
Nitrobenzene Solution ◽  
Ligand Structure ◽  
Stability Constants Of Complexes ◽  
Separation Factors ◽  
The Stability ◽  
A Minor

Extraction of microamounts of Sr2+ and Ba2+ (henceforth M2+) from the aqueous solutions of perchloric acid (0.0125-1.02 mol/l) by means of the nitrobenzene solutions of dicarbolide (0.004-0.05 mol/l of H+{Co(C2B9H11)2}-) was studied in the presence of monoglyme (only Ba2+), diglyme, triglyme, and tetraglyme (CH3O-(CH2-CH2O)nCH3, where n = 1, 2, 3, 4). The distribution of glyme betweeen the aqueous and organic phases, the extraction of the protonized glyme molecule HL+ together with the extraction of M2+ ion and of the glyme complex with the M2+ ion, i.e., ML2+ (where L is the molecule of glyme), were found to be the dominating reactions in the systems under study. In the systems with tri- and tetraglymes the extraction of H+ and M2+ ions solvated with two glyme molecules, i.e., the formation of HL2+ and ML22+ species, can probably play a minor role. The values of the respective equilibrium constants, of the stability constants of complexes formed in the organic phase, and the theoretical separation factors αBa/Sr were determined. The effect of the ligand structure on the values of extraction and stability constants in the organic phase is discussed.

scholarly journals Engineering motile aqueous phase-separated droplets via liposome stabilisation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shaobin Zhang ◽  
Claudia Contini ◽  
James W. Hindley ◽  
Guido Bolognesi ◽  
Yuval Elani ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Marangoni Effect ◽  
Living Systems ◽  
Biological Processes ◽  
Biological Applications ◽  
Emulsion System ◽  
Biotechnological Potential ◽  
New Directions ◽  
Directional Motion ◽  
The Stability

AbstractThere are increasing efforts to engineer functional compartments that mimic cellular behaviours from the bottom-up. One behaviour that is receiving particular attention is motility, due to its biotechnological potential and ubiquity in living systems. Many existing platforms make use of the Marangoni effect to achieve motion in water/oil (w/o) droplet systems. However, most of these systems are unsuitable for biological applications due to biocompatibility issues caused by the presence of oil phases. Here we report a biocompatible all aqueous (w/w) PEG/dextran Pickering-like emulsion system consisting of liposome-stabilised cell-sized droplets, where the stability can be easily tuned by adjusting liposome composition and concentration. We demonstrate that the compartments are capable of negative chemotaxis: these droplets can respond to a PEG/dextran polymer gradient through directional motion down to the gradient. The biocompatibility, motility and partitioning abilities of this droplet system offers new directions to pursue research in motion-related biological processes.

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