Search results for "MIM"
showing 10 items of 645 documents
Malonato complexes of oxidovanadium(IV): Synthesis, structural characterization and exploration of their insulin mimetic properties
2011
Abstract Several bis-malonatooxidovanadium(IV) complexes of the general type [M2(H2O)n][VO(mal)2(H2O)] (where M = Li(1), Na(2), K(3), Cs(4) and NH4(5); n = 3.5, 1, 3, 1 and 1, respectively) were isolated in good yield and high purity. These complexes were fully characterized by various physicochemical techniques (elemental analysis, UV–Vis, IR, EPR, CV, etc.) complexes 1, 2 and 3 were structurally characterized by single crystal X-ray diffraction technique. In vivo antidiabetic properties of bis-malonato complexes 1, 2, 3 and 5 have been studied using Streptozotocin induced diabetic rats. Significant lowering of blood sugar level has been noticed. At the same time these complexes were found…
Bioinspired self-assembly of tyrosinase-modified silicatein and fluorescent core-shell silica spheres.
2014
Inspired by the intermolecular cross-linking of mussel foot proteins and their adhesive properties, tyrosinase has been used to modify recombinant silicatein. DOPA/DOPAquinone-mediated cross-linking and interfacial interactions enhanced both self-assembly of silicatein building blocks and templating of core–shell silica spheres, resulting in fluorescent biomimetic silicatein–silica hybrid mesofibers.
A pH-tunable nanofluidic diode: electrochemical rectification in a reconstituted single ion channel.
2006
We report pH-dependent electrochemical rectification in a protein ion channel (the bacterial porin OmpF) reconstituted on a planar phospholipid membrane. The measurements performed at single-channel level show that the electric current is controlled by the protein fixed charge and it can be tuned by adjusting the local pH. Under highly asymmetric pH conditions, the channel behaves like a liquid diode. Unlike other nanofluidic devices that display also asymmetric conductance, here the microscopic charge distribution of the system can be explored by using the available high-resolution (2.4 A) channel crystallographic structure. Continuum electrostatics calculations confirm the hypothesized bi…
Nonlinear chiral transport in Dirac semimetals
2018
We study the current of chiral charge density in a Dirac semimetal with two Dirac points in momentum space, subjected to an externally applied time dependent electric field and in the presence of a magnetic field. Based on the kinetic equation approach, we find contributions to the chiral charge current, that are proportional to the second power of the electric field and to the first and second powers of the magnetic field, describing the interplay of the chiral anomaly and the drift motion of electrons moving under the action of electric and magnetic fields.
Atropine-resistant effects of the muscarinic agonists McN-A-343 and AHR 602 on cardiac performance and the release of noradrenaline from sympathetic …
1974
Abstract 1 The effects of 4-(m-chlorophenylcarbamoyloxy)-2-butynyltrimethylammonium chloride (McN-A-343) and N-benzyl-3-pyrrolidyl acetate methobromide (AHR 602) on cardiac performance and noradrenaline release from terminal sympathetic fibres were measured in isolated perfused hearts of rabbits. 2 In the presence of sufficient atropine to block muscarinic receptors, high concentrations of McN-A-343 and AHR 602 caused no cardiac stimulation and there was no increase in the resting output of noradrenaline into the perfusates. 3 McN-A-343 and AHR 602 increased both the mechanical responses and the transmitter overflow evoked by electrical stimulation of the sympathetic nerves (SNS) but inhibi…
How copper ions and membrane environment influence the structure of the human and chicken tandem repeats domain?
2019
Abstract Prion proteins (PrPs) from different species have the enormous ability to anchor copper ions. The N-terminal domain of human prion protein (hPrP) contains four tandem repeats of the –PHGGGWGQ– octapeptide sequence. This octarepeat domain can bind up to four Cu2+ ions. Similarly to hPrP, chicken prion protein (chPrP) is able to interact with Cu2+ through the tandem hexapeptide -HNPGYP- region (residues 53–94). In this work, we focused on the human octapeptide repeat (human Octa4, hPrP60–91) (Ac-PHGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQ-NH2) and chicken hexapeptide repeat (chicken Hexa4, chPrP54–77) (Ac-HNPGYPHNPGYPHNPGYPHNPGYP-NH2) prion protein fragments. Due to the fact that PrP is a membr…
VCD studies on cyclic peptides assembled from L-α-amino acids and a trans-2-aminocyclopentane- or trans-2-aminocyclohexane carboxylic acid.
2010
The increasing interest in peptidomimetics of biological relevance prompted us to synthesize a series of cyclic peptides comprising trans-2-aminocyclohexane carboxylic acid (Achc) or trans-2-aminocyclopentane carboxylic acid (Acpc). NMR experiments in combination with MD calculations were performed to investigate the three-dimensional structure of the cyclic peptides. These data were compared to the conformational information obtained by electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectroscopy. Experimental VCD spectra were compared to theoretical VCD spectra computed quantum chemically at B3LYP/6-31G(d) density functional theory (DFT) level. The good agreem…
Novel atrazine-binding biomimetics inspired to the D1 protein from the photosystem II of Chlamydomonas reinhardtii.
2020
Biomimetic design represents an emerging field for improving knowledge of natural molecules, as well as to project novel artificial tools with specific functions for biosensing. Effective strategies have been exploited to design artificial bioreceptors, taking inspiration from complex supramolecular assemblies. Among them, size-minimization strategy sounds promising to provide bioreceptors with tuned sensitivity, stability, and selectivity, through the ad hoc manipulation of chemical species at the molecular scale. Herein, a novel biomimetic peptide enabling herbicide binding was designed bioinspired to the D1 protein of the Photosystem II of the green alga Chlamydomonas reinhardtii. The D1…
Size-exclusion high-performance liquid chromatography in the study of the autoassociating antibiotic gramicidin A in micellar milieu.
2003
Gramicidin A (gA) is a polypeptide antibiotic which forms dimeric channels specific for monovalent cations in biological membranes. It is a polymorphic molecule that adopts several different conformations, double-stranded (ds) helical dimers (pore conformation) and single-stranded beta-helical dimers (channel conformation). This study investigated the conformational adaptability of gramicidin A when incorporated into micelles as membrane-mimetic model system. Taking advantage of our reported, versatile, size-exclusion high-performance liquid chromatography (SE-HPLC) strategy that allows the separation of double-stranded dimers and monomers, we have quantitatively characterized the conformat…
Conceptual basis of cognitive mimetics for information engineering
2021
Abstract Intelligent information processing is topical in modern technology design and development. The fundamental idea was developed by Turing as he made the first conceptual models of information-processing computers. Though it has practically never been noticed, Turing’s work was a model of how to mimic human intelligent information processes and generate technologies, which can carry out intelligent tasks. The design method can be called cognitive mimetics as it imitates human information processes to design technologies and their applications. One can use cognitive mimetics even in solving techno-ethical problems. This is why we think that cognitive mimetics are vital as a method to g…