21 research outputs found

    Scan time of audible and inaudible session.

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    <p>Box-and-whisker plots show scan time of the audible and inaudible sessions of all 52 kidneys, the time needed to obtain reproducible waveforms is significantly shorter during the audible than the inaudible sessions (p<0.001).</p

    Scan time of right and left kidney.

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    <p>Box-and-whisker plots show Doppler sonographic scan time of right and left kidney during each session. There are no significant differences in the scan times between the right and left kidneys during the audible (A) and inaudible sessions (B).</p

    Mitochondrial Thioredoxin-Responding Off–On Fluorescent Probe

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    We synthesized a new probe, Mito-Naph, to visualize mitochondrial thioredoxin (Trx) activity in cells. A fluorescence off–on change is induced by disulfide cleavage of the probe, resulting from a reaction with Trx and subsequent intramolecular cyclization by the released thiolate to give a fluorescent product. By measuring the fluorescence at 540 nm, Trx activity can be detected at nanomolar concentrations (down to 50 nM) well below its physiological levels. The in vitro and in vivo Trx preference of Mito-Naph was demonstrated by fluorometric and confocal microscopic experiments. In vitro kinetic analysis of the disulfide bond cleavage revealed that the second-order rate constant for Trx is (4.04 ± 0.26) × 10<sup>3</sup> (M s)<sup>−1</sup>, approximately 5000 times faster than that for GSH. The inhibition experiments involving PX-12, a selective inhibitor of Trx, also revealed that the emission from Mito-Naph significantly decreased in PX-12 dose-dependent manners, both in living cells and in cellular protein extracts. The Trx preference was further supported by an observation that the fluorescence intensity of rat liver extract was decreased according to the Trx depletion by immunoprecipitation. On the basis of these results, it is concluded that Mito-Naph preferentially reacts with Trx, compared with other biological thiols containing amino acids in vitro and in vivo

    A fluorogenic calix[4]pyrrole with a small rigid strap showing different fluorescent responses to anions

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    <p>A strapped calix[4]pyrrole (<b>2</b>) with a fluorogenic pyrene unit linked to the rigid strap via the methylene bridge has been synthesised. It was established by <sup>1</sup>H NMR and fluorescence spectroscopic analyses and isothermal titration calorimetry (ITC) studies that receptor <b>2</b> is capable of binding the F<sup>−</sup>, Cl<sup>−</sup>, (ppi) and anions in organic media, with high selectivity for F<sup>−</sup> being observed relative to the other anions. Upon exposure to the F<sup>−</sup> and , the fluorescence of <b>2</b> is quenched, an effect ascribed to facilitated PET (photo-induced electron transfer) from the nitrogen atom to the pyrene moiety, which is induced by anion binding. In contrast, the fluorescence of <b>2</b> was enhanced upon treatment with the HSO<sub>4</sub><sup>−</sup> anion as the result of the PET inhibition that results from nitrogen atom protonation. A single crystal X-ray structure of the chloride complex of <b>2</b> and the <sup>1</sup>H NMR spectral data revealed that the chloride anion is bound to the receptor via aliphatic C–H•••Cl<sup>−</sup> hydrogen bonds, as well as N–H•••Cl<sup>−</sup> interactions.</p

    Delayed leaf senescence symptoms in the <i>ddm1-2</i> as well as in the <i>drd1-6</i> mutant.

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    <p>(A) Phenotypes of detached WT, <i>drd1-6</i>, <i>drd1-p</i> and <i>ddm1-2</i> leaves after 0, 3, and 5-d dark incubation. (B) Photochemical efficiency of photosystem II (Fv/Fm) in WT and mutant leaves in (A). Data represent average values ± SE (n = 27) of three independent experiments. Bars with the same letter are not significantly different at <i>P</i> < 0.05 by Tukey’s honestly significant difference (HSD) test.</p

    Toward a Chemical Marker for Inflammatory Disease: A Fluorescent Probe for Membrane-Localized Thioredoxin

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    Thioredoxin (Trx) is a redox-active protein that plays a key role in mitigating the effects of oxidative stress. The secretion of Trx on the plasma membrane has been suggested as a distinctive feature of inflammation. However, selective monitoring of membrane-associated Trx activity has proved challenging because of the ubiquity of Trx action in cells. Here, we report a Trx-specific probe that allows visualization of Trx activity associated with the membranes via fluorescence microscopy. The ability of this probe to act as a possible screening tool for agents that modulate Trx secretion was demonstrated in HeLa cells under oxidative stress conditions and in a cellular hepatosteatosis model. Control experiments serve to confirm that the response seen for the present probe is due to Trx and that it is selective over various potentially competing metabolites, including thiol-containing small molecules and test proteins

    Delayed leaf senescence symptoms in the <i>drd1-6</i> mutant at later developmental stages.

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    <p>Rosette leaves of 28-day-old WT and the 34, 36, and 38-day-old <i>drd1-6</i> mutants were detached and darkened for 0, 3, 5 days. Photochemical efficiency of photosystem II (Fv/Fm) in WT and mutant leaves was examined at the indicated days. Data represent average values ± SE (n = 20) of independent experiments. Bars with the same letter are not significantly different at <i>P</i> < 0.05 by Tukey’s honestly significant difference (HSD) test.</p

    The positions of mutations and expression of <i>DRD1</i> gene.

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    <p>(A) Domain structures of DRD1 and DDM1 and positions of <i>drd1-6</i>, <i>drd1-p</i> and <i>ddm1-2</i>. Amino acid sequence change from tryptophan (W) to stop codon in helicase superfamily C-terminal (HELICc) domain in <i>drd1-6</i>. The triangle indicates the position of T-DNA insertion in <i>drd1-p</i> mutant. In case of <i>ddm1-2</i>, substitution of G to A in the splice donor site of intron 11 brings about lack of helicase superfamily C-terminal (HELICc) domain. (B) RT-PCR analysis of <i>DRD1</i> and control <i>ACTIN2</i> genes in WT and <i>drd1-p</i> mutant leaves. The <i>drd1-p</i> mutant displayed a decrease in <i>DRD1</i> expression levels compared to WT.</p

    Direct Fluorescence Monitoring of the Delivery and Cellular Uptake of a Cancer-Targeted RGD Peptide-Appended Naphthalimide Theragnostic Prodrug

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    Presented here is a multicomponent synthetic strategy that allows for the direct, fluorescence-based monitoring of the targeted cellular uptake and release of a conjugated therapeutic agent. Specifically, we report here the design, synthesis, spectroscopic characterization, and preliminary in vitro biological evaluation of a RGD peptide-appended naphthalimide pro-CPT (compound <b>1</b>). Compound <b>1</b> is a multifunctional molecule composed of a disulfide bond as a cleavable linker, a naphthalimide moiety as a fluorescent reporter, an RGD cyclic peptide as a cancer-targeting unit, and camptothecin (CPT) as a model active agent. Upon reaction with free thiols in aqueous media at pH 7.4, disulfide cleavage occurs. This leads to release of the free CPT active agent, as well as the production of a red-shifted fluorescence emission (λ<sub>max</sub> = 535 nm). Confocal microscopic experiments reveal that <b>1</b> is preferentially taken up by U87 cells over C6 cells. On the basis of competition experiments involving okadaic acid, an inhibitor of endocytosis, it is concluded that uptake takes place via RGD-dependent endocytosis mechanisms. In U87 cells, the active CPT payload is released within the endoplasmic reticulum, as inferred from fluorescence-based colocalization studies using a known endoplasmic reticulum-selective dye. The present drug delivery system (DDS) could represent a new approach to so-called theragnostic agent development, wherein both a therapeutic effect and drug uptake-related imaging information are produced and can be readily monitored at the subcellular level. In due course, the strategy embodied in conjugate <b>1</b> could allow for more precise monitoring of dosage levels, as well as an improved understanding of cellular uptake and release mechanisms

    Delayed leaf senescence symptoms in the <i>drd1-6</i> mutant.

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    <p>(A) Phenotypes of 28-day-old and 55-day-old wild-type (WT) and <i>drd1-6</i> mutant whole plants. (B) Individually darkened leaf (IDL) senescence of WT (left) and <i>drd1-6</i> (right) plants. Rosette leaves of 28-day-old WT and <i>drd1-6</i> mutant (IDL 0 d) were induced to undergo senescence for 5 d under dark conditions (IDL 5 d). The red and blue arrows indicate 5 d IDL of WT and <i>drd1-6</i> plants, respectively. (C) Phenotypes of detached WT and <i>drd1-6</i> leaves after 5-d dark incubation. (D) Photochemical efficiency of photosystem II (Fv/Fm) and (E) maximal electron transport rate (ETRmax) in WT and the <i>drd1-6</i> leaves were examined at the indicated days during dark-induced senescence (DIS). Data represent average values ± SE (n = 27) of three independent experiments. * indicates <i>P</i> < 0.01 by student’s t-test.</p
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