2,660 research outputs found
Specificity of aequorin luminescence to calcium
The presence of Pb(++), Co(++), Cu(++), and Cd(++), each of which possesses a certain luminescence-triggering activity of aequorin, potentially interferes with the specificity of the aequorin luminescence response to Ca(++). Interference by the above cations can be eliminated, without influencing the sensitivity of the luminescence of aequorin to Ca(++), by adding 1 mM of sodium diethyldithiocarbamate
Resistivity to denaturation of the apoprotein of aequorin and reconstitution of the luminescent photoprotein from the partially denatured apoprotein
Topological enhancement of non-normality in non-Hermitian skin effects
The non-Hermitian skin effects are representative phenomena intrinsic to
non-Hermitian systems: the energy spectra and eigenstates under the open
boundary condition (OBC) drastically differ from those under the periodic
boundary condition (PBC). Whereas a non-trivial topology under the PBC
characterizes the non-Hermitian skin effects, their proper measure under the
OBC has not been clarified yet. This paper reveals that topological enhancement
of non-normality under the OBC accurately quantifies the non-Hermitian skin
effects. Correspondingly to spectrum and state changes of the skin effects, we
introduce two scalar measures of non-normality and argue that the non-Hermitian
skin effects enhance both macroscopically under the OBC. We also show that the
enhanced non-normality correctly describes phase transitions causing the
non-Hermitian skin effects and reveals the absence of non-Hermitian skin
effects protected by average symmetry. The topological enhancement of
non-normality governs the perturbation sensitivity of the OBC spectra and the
anomalous time-evolution dynamics through the Bauer-Fike theorem.Comment: 33 pages, 14 figure
Establishment of a New Cell-Based Assay To Measure the Activity of Sweeteners in Fluorescent Food Extracts
Taste receptors have been defined at the molecular level in the past decade, and cell-based assays have been developed using cultured cells heterologously expressing these receptors. The most popular approach to detecting the cellular response to a tastant is to measure changes in intracellular Ca2+ concentration using Ca2+-sensitive fluorescent dyes. However, this method cannot be applied to food-derived samples that contain fluorescent substances. To establish an assay system that would be applicable to fluorescent samples, we tested the use of Ca2+-sensitive photoproteins, such as aequorin and mitochondrial clytin-II, as Ca2+ indicators in a human sweet taste receptor assay. Using these systems, we successfully detected receptor activation in response to sweetener, even when fluorescent compounds coexisted. This luminescence-based assay will be a powerful tool to objectively evaluate the sweetness of food-derived samples even at an industry level
Possible adsorption mechanism of high mobility group box 1 protein on a polyacrylonitrile (AN69ST) membrane filter
The relative rate of aequorin regeneration from apoaequorin and coelenterazine analogues
Semi-synthetic aequorin. An improved tool for the measurement of calcium ion concentration
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