Cyclo-oligo-(1→6)-β-D-glucosamines functionalized with hydrophobic tails are reported as a new class of transmembrane ion-transport system. These macrocycles with hydrophilic cavities were introduced as an alternative to cyclodextrins, which are supramolecular systems with hydrophobic cavities. The transport activities of these glycoconjugates were manipulated by altering the oligomericity of the macrocycles, as well as the length and number of attached tails. Hydrophobic tails of 3 different sizes were synthesized and coupled with each glucosamine scaffold through the amide linkage to obtain 18 derivatives. The ion-transport activity increased from di- to tetrameric glucosamine macrocycles, but decreased further when flexible pentameric glucosamine was introduced. The ion-transport activity also increased with increasing length of attached linkers. For a fixed length of linkers, the transport activity decreased when the number of such tails was reduced. All glycoconjugates displayed a uniform anion-selectivity sequence: Cl(-) >Br(-) >I(-) . From theoretical studies, hydrogen bonding between the macrocycle backbone and the anion bridged through water molecules was observed.
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http://dx.doi.org/10.1002/chem.201502656 | DOI Listing |
Sci Adv
January 2025
Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA.
ACS Nano
January 2025
Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
We present a strategy for enhancing Li conduction in block copolymer electrolytes by introducing trace amounts of Li salts into polystyrene--poly(ethylene oxide) (PS--PEO), wherein Li ions preferentially coordinate with the -OH end groups of the PEO chains, resulting in the formation of double primitive cubic (3̅) structures. Compared with TFSI anions in Li salts, smaller anions (PF and BF) could facilitate ion localization more effectively, expanding the salt concentration range for developing stable 3̅ structures. The 3̅ structures formed in PS--PEOs doped with LiBF at = 0.
View Article and Find Full Text PDFJ Comp Physiol B
January 2025
Departamento de Fisiologia, Instituto de Biociências da Universidade de São Paulo, São Paulo, Brazil.
During the transition from fresh waters to terrestrial habitats, significant adaptive changes occurred in kidney function of vertebrates to cope with varying osmotic challenges. We investigated the mechanisms driving water conservation in the mammalian nephron, focusing on the relative contributions of active ion transport and Starling forces. We constructed a thermodynamic model to estimate the entropy generation associated with different processes within the nephron, and analyzed their relative importance in urine formation.
View Article and Find Full Text PDFNat Commun
January 2025
School of Infection and Immunity, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK.
For the protozoan parasite Leishmania, completion of its life cycle requires sequential adaptation of cellular physiology and nutrient scavenging mechanisms to the different environments of a sand fly alimentary tract and the acidic mammalian host cell phagolysosome. Transmembrane transporters are the gatekeepers of intracellular environments, controlling the flux of solutes and ions across membranes. To discover which transporters are vital for survival as intracellular amastigote forms, we carried out a systematic loss-of-function screen of the L.
View Article and Find Full Text PDFNat Commun
January 2025
School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK.
The refinement of neural circuits towards mature function is driven during development by patterned spontaneous calcium-dependent electrical activity. In the auditory system, this sensory-independent activity arises in the pre-hearing cochlea and regulates the survival and refinement of the auditory pathway. However, the origin and interplay of calcium signals during cochlear development is unknown in vivo.
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