scholarly journals Investigating the Influence of Steric Hindrance on Selective Anion Transport

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1278 ◽  
Author(s):  
Laura Jowett ◽  
Angela Ricci ◽  
Xin Wu ◽  
Ethan Howe ◽  
Philip Gale
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Steric Hindrance ◽  
Chloride Transport ◽  
Anion Transport ◽  
Anion Binding ◽  
Chloride Binding ◽  
Anion Receptors ◽  
Flip Flop ◽  
Anion Transporters

A series of symmetrical and unsymmetrical alkyl tren based tris-thiourea anion transporters were synthesised and their anion binding and transport properties studied. Overall, increasing the steric bulk of the substituents resulted in improved chloride binding and transport abilities. Including a macrocycle in the scaffold enhanced the selectivity of chloride transport in the presence of fatty acids, by reducing the undesired H+ flux facilitated by fatty acid flip-flop. This study demonstrates the benefit of including enforced steric hindrance and encapsulation in the design of more selective anion receptors.

scholarly journals Selective anion transport mediated by strap-extended calixpyrroles

2020 ◽  
Vol 24 (01n03) ◽  
pp. 473-479 ◽  
Author(s):  
Harriet J. Clarke ◽  
Xin Wu ◽  
Mark E. Light ◽  
Philip A. Gale
Keyword(s):  
Fatty Acids ◽  
Chloride Transport ◽  
Anion Transport ◽  
Anion Binding ◽  
Anion Receptors ◽  
Future Design ◽  
Anion Transporters ◽  
Head Groups ◽  
Proton Leakage ◽  
Autophagy Inhibition

Synthetic anion receptors that facilitate transmembrane chloride transport are of interest as potential therapeutic agents for cancer and cystic fibrosis. Transporters selective for chloride over protons are desired for therapeutic applications to avoid autophagy inhibition and cytotoxicity. Examples of such compounds are rare because the majority of anion transporters can interact with the carboxylate head groups of fatty acids leading to proton leakage. In this paper, we report the synthesis, anion binding and transmembrane anion transport properties of two novel bis-triazole-functionalized calixpyrroles with extended straps, and compare them to previously reported shorter-strap analogues known to exhibit high Cl [Formula: see text] H[Formula: see text] selectivity. We demonstrate improved chloride transport activities of the strap-extended compounds that likely benefit from increased lipophilicity, and reduced Cl [Formula: see text] H[Formula: see text] selectivity due to the larger anion binding cavities facilitating interaction with fatty acids. The results are instructive for future design of ideal anion transporters with potent activity and high selectivity against proton leakage.

scholarly journals Tetrapodal Anion Transporters

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5179
Author(s):  
Alexander M. Gilchrist ◽  
Lijun Chen ◽  
Xin Wu ◽  
William Lewis ◽  
Ethan N.W. Howe ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Side Effect ◽  
Proton Transport ◽  
High Selectivity ◽  
Chloride Transport ◽  
Anion Transporters ◽  
Selective Interaction

Synthetic anion transporters that facilitate chloride transport are promising candidates for channelopathy treatments. However, most anion transporters exhibit an undesired side effect of facilitating proton transport via interacting with fatty acids present in the membrane. To address the limitation, we here report the use of a new tetrapodal scaffold to maximize the selective interaction with spherical chloride over binding the carboxylate headgroup of fatty acids. One of the new transporters demonstrated a high selectivity for chloride uniport over fatty acid-induced proton transport while being >10 times more active in chloride uniport than strapped calixpyrroles that were previously the only class of compounds known to possess similar selectivity properties.

scholarly journals Fatty Acid Fueled Transmembrane Chloride Transport

2019 ◽  
Author(s):  
Ethan N.W. Howe ◽  
Philip Gale
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Bilayer ◽  
Chloride Transport ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Ph Gradient ◽  
Pumping System ◽  
Membrane Addition

We report an example of the use of fatty acids to drive chloride transport by creating a pH gradient across a vesicular lipid bilayer membrane. Addition of an unselective squaramide-based chloride transporter (which transports both H<sup>+</sup>and Cl<sup>-</sup>) facilitates the transport of HCl from the vesicle (driven by the pH gradient) so creating a chloride gradient. Addition of further aliquots of fatty acid ‘fuel’ can initiate further transport of chloride out of the vesicle by re-establishing the pH gradient. This is an example of a prototypical chloride pumping system.

scholarly journals Transmembrane Fluoride Transport by a Cyclic Azapeptide With Two β-Turns

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhixing Zhao ◽  
Miaomiao Zhang ◽  
Bailing Tang ◽  
Peimin Weng ◽  
Yueyang Zhang ◽  
...  
Keyword(s):  
Chloride Transport ◽  
Anion Transport ◽  
Bacterial Survival ◽  
Transport Activity ◽  
Selective Electrode ◽  
Design And Synthesis ◽  
Anion Transporters ◽  
Host Compound ◽  
Anion Transport Activity ◽  
Fluoride Ion Selective Electrode

Diverse classes of anion transporters have been developed, most of which focus on the transmembrane chloride transport due to its significance in living systems. Fluoride transport has, to some extent, been overlooked despite the importance of fluoride channels in bacterial survival. Here, we report the design and synthesis of a cyclic azapeptide (a peptide-based N-amidothiourea, 1), as a transporter for fluoride transportation through a confined cavity that encapsulates fluoride, together with acyclic control compounds, the analogs 2 and 3. Cyclic receptor 1 exhibits more stable β-turn structures than the control compounds 2 and 3 and affords a confined cavity containing multiple inner –NH protons that serve as hydrogen bond donors to bind anions. It is noteworthy that the cyclic receptor 1 shows the capacity to selectively transport fluoride across a lipid bilayer on the basis of the osmotic and fluoride ion-selective electrode (ISE) assays, during which an electrogenic anion transport mechanism is found operative, whereas no transmembrane transport activity was found with 2 and 3, despite the fact that 2 and 3 are also able to bind fluoride via the thiourea moieties. These results demonstrate that the encapsulation of an anionic guest within a cyclic host compound is key to enhancing the anion transport activity and selectivity.

scholarly journals Fatty Acid-Fuelled Transmembrane Chloride Transport

2018 ◽  
Author(s):  
Philip Gale ◽  
Ethan N.W.Howe
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Bilayer ◽  
Chloride Transport ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Ph Gradient ◽  
Pumping System ◽  
Membrane Addition

We report an example of the use of fatty acids to drive chloride transport by creating a pH gradient across a vesicular lipid bilayer membrane. Addition of an unselective squaramide-based chloride transporter (which transports both H<sup>+</sup>and Cl<sup>-</sup>) facilitates the transport of HCl from the vesicle (driven by the pH gradient) so creating a chloride gradient. Addition of further aliquots of fatty acid ‘fuel’ can initiate further transport of chloride out of the vesicle by re-establishing the pH gradient. This is an example of a prototypical chloride pumping system.

scholarly journals Fatty Acid Fueled Transmembrane Chloride Transport

2019 ◽  
Author(s):  
Ethan N.W. Howe ◽  
Philip Gale
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Bilayer ◽  
Chloride Transport ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Ph Gradient ◽  
Pumping System ◽  
Membrane Addition

We report an example of the use of fatty acids to drive chloride transport by creating a pH gradient across a vesicular lipid bilayer membrane. Addition of an unselective squaramide-based chloride transporter (which transports both H<sup>+</sup>and Cl<sup>-</sup>) facilitates the transport of HCl from the vesicle (driven by the pH gradient) so creating a chloride gradient. Addition of further aliquots of fatty acid ‘fuel’ can initiate further transport of chloride out of the vesicle by re-establishing the pH gradient. This is an example of a prototypical chloride pumping system.

scholarly journals Carbazole-Based Colorimetric Anion Sensors

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3205
Author(s):  
Krystyna Maslowska-Jarzyna ◽  
Maria L. Korczak ◽  
Jakub A. Wagner ◽  
Michał J. Chmielewski
Keyword(s):  
Hydrogen Bond ◽  
Visible Region ◽  
Building Blocks ◽  
Anion Transport ◽  
Anion Binding ◽  
Anion Receptors ◽  
Binding Studies ◽  
Anion Sensor ◽  
Anion Sensors ◽  
Anion Interaction

Owing to their strong carbazole chromophore and fluorophore, as well as to their powerful and convergent hydrogen bond donors, 1,8-diaminocarbazoles are amongst the most attractive and synthetically versatile building blocks for the construction of anion receptors, sensors, and transporters. Aiming to develop carbazole-based colorimetric anion sensors, herein we describe the synthesis of 1,8-diaminocarbazoles substituted with strongly electron-withdrawing substituents, i.e., 3,6-dicyano and 3,6-dinitro. Both of these precursors were subsequently converted into model diamide receptors. Anion binding studies revealed that the new receptors exhibited significantly enhanced anion affinities, but also significantly increased acidities. We also found that rear substitution of 1,8-diamidocarbazole with two nitro groups shifted its absorption spectrum into the visible region and converted the receptor into a colorimetric anion sensor. The new sensor displayed vivid color and fluorescence changes upon addition of basic anions in wet dimethyl sulfoxide, but it was poorly selective; because of its enhanced acidity, the dominant receptor-anion interaction for most anions was proton transfer and, accordingly, similar changes in color were observed for all basic anions. The highly acidic and strongly binding receptors developed in this study may be applicable in organocatalysis or in pH-switchable anion transport through lipophilic membranes.

scholarly journals Fatty Acid Fueled Transmembrane Chloride Transport

2019 ◽  
Author(s):  
Ethan N.W. Howe ◽  
Philip Gale
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Bilayer ◽  
Chloride Transport ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Ph Gradient ◽  
Pumping System ◽  
Membrane Addition

We report an example of the use of fatty acids to drive chloride transport by creating a pH gradient across a vesicular lipid bilayer membrane. Addition of an unselective squaramide-based chloride transporter (which transports both H<sup>+</sup>and Cl<sup>-</sup>) facilitates the transport of HCl from the vesicle (driven by the pH gradient) so creating a chloride gradient. Addition of further aliquots of fatty acid ‘fuel’ can initiate further transport of chloride out of the vesicle by re-establishing the pH gradient. This is an example of a prototypical chloride pumping system.

Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

1985 ◽  
Vol 54 (03) ◽  
pp. 563-569 ◽  
Author(s):  
M K Salo ◽  
E Vartiainen ◽  
P Puska ◽  
T Nikkari
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Free Living ◽  
Ω3 Fatty Acids ◽  
Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

EFFECT OF GINGER, LEMURU FISH OIL SAPONIFICATION AND OLIVE OIL ON COMPOSITION FATTY ACID OF BEEF

2014 ◽  
Vol 4 (1) ◽  
pp. 31-39
Author(s):  
Siwitri Kadarsih
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fish Oil ◽  
Olive Oil ◽  
Rice Bran ◽  
Dry Matter ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Omega 3 ◽  
Omega 6

The objective was to get beef that contain unsaturated fatty acids (especially omega 3 and 6), so as to improve intelligence, physical health for those who consume. The study design using CRD with 3 treatments, each treatment used 4 Bali cattle aged approximately 1.5 years. Observations were made 8 weeks. Pasta mixed with ginger provided konsentrat. P1 (control); P2 (6% saponification lemuru fish oil, olive oil 1%; rice bran: 37.30%; corn: 62.70%; KLK: 7%, ginger paste: 100 g); P3 (lemuru fish oil saponification 8%, 2% olive oil; rice bran; 37.30; corn: 62.70%; KLK: 7%, ginger paste: 200 g). Konsentrat given in the morning as much as 1% of the weight of the cattle based on dry matter, while the grass given a minimum of 10% of the weight of livestock observation variables include: fatty acid composition of meat. Data the analyzies qualitative. The results of the study showed that the composition of saturated fatty acids in meat decreased and an increase in unsaturated fatty acids, namely linoleic acid (omega 6) and linolenic acid (omega 3), and deikosapenta deikosaheksa acid.Keywords : 

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