Excimer Emission-Based Fluorescent Probe Targeting Caspase‑3

A fluorescent probe based on an excimer-forming benzothiazolyl-cyanovinylene (<b>CV</b>) dye was developed to target the apoptotic protease caspase-3. Upon the action of caspase-3, the water-soluble fluorescent probe Ac-DEVD-<b>NH-CV</b>, which is weakly green emissive in aqueous solution, is converted to hydrophobic <b>CV-NH₂</b>, which spontaneously aggregates. Aggregation of <b>CV-NH₂</b> promotes excimer emission of the <b>CV</b> dye, which allows for the study of caspase-3 activity <i>in vitro</i> and for imaging the activity of the enzyme in living cells because of the large red shift and enhanced fluorescence signal of the probe

Instantaneous Colorimetric and Fluorogenic Detection of Phosgene with a <i>meso</i>-Oxime-BODIPY

The <i>meso</i>-oxime-substituted-1,3,5,7-tetramethyl BODIPY (<b>1-oxime</b>) was developed into a colorimetric and fluorogenic probe to selectively detect and quantify phosgene. The fast (<10 s) and sensitive (LOD = 0.09 ppb) phosgene detection is achieved by the conversion of the <i>meso</i>-oxime to the <i>meso</i>-nitrile, resulting in a large fluorescence turn-on response. The utility of <b>1-oxime</b> was established for the visual detection of phosgene in solution and in a practical solid-state platform, making it a suitable candidate for on-site monitoring of phosgene gas exposure in the workplace

Molecular Rotors for the Detection of Chemical Warfare Agent Simulants

The fluorogenic probe <i>o</i>-OH is able to detect and quantify organophosphorus nerve agent mimics in solution and in the vapor phase following immobilization on a solid substrate, making the system a suitable candidate for the field detection of chemical warfare agents. Detection is achieved by the suppression of internal rotation upon phosphorylation of a reactive phenolate, resulting in a large fluorescence “turn-on” response

DataSheet1_Inhibition of cellulase activity by liquid hydrolysates from hydrothermally pretreated soybean straw.PDF

The one-pot biomass conversion process is a promising strategy to minimize potential product loss and reduce processing costs. However, this strategy has technical limitations due to the inhibitory effects of biomass components like lignin as well as the generated inhibitors (e.g., furans, phenols) during biomass processing. In this study, the inhibitory effects of liquid hydrolysates formed by hydrothermal pretreatment of soybean straw with either sodium hydroxide (NaOH) or hydrogen peroxide (H2O2) on cellulolytic enzyme activity were investigated. Hydrothermal pretreatment of soybean straw (10% w/v) was carried out with either sodium hydroxide (1% v/v) or hydrogen peroxide (1% v/v) at 121°C for 60 min to evaluate the effect of water-soluble inhibitors released from soybean pretreatment on cellulolytic enzyme activity. The fraction of cellulose in pretreated solids (1% w/v glucan) was enzymatically hydrolyzed for 72 h with 45 IU/g glucan (corresponding to 25 mg enzyme protein/g glucan) in the presence of either buffer or liquid hydrolysate generated from the pretreatments. Hydrolysis of NaOH and H2O2 pretreated solids resulted in 57% and 39% of glucose yields in buffer, respectively. In the presence of the liquid hydrolysates, NaOH and H2O2 pretreated biomass showed 20% and 30% glucose yield, respectively, indicating the enzyme suppression by inhibitors in the liquid hydrolysates. Of the enzyme activities in hydrolysates tested, NaOH hydrolysate showed a higher inhibitory effect on enzyme activities (mainly β-glucosidase) compared to H2O2 liquid, where enzyme deactivation has a first-order correlation and the manner in which the vacuum-filtered inhibitors were generated from pretreated soybean straw.</p

Selection of an Aptamer Antidote to the Anticoagulant Drug Bivalirudin

<div><p>Adverse drug reactions, including severe patient bleeding, may occur following the administration of anticoagulant drugs. Bivalirudin is a synthetic anticoagulant drug sometimes employed as a substitute for heparin, a commonly used anticoagulant that can cause a condition called heparin-induced thrombocytopenia (HIT). Although bivalrudin has the advantage of not causing HIT, a major concern is lack of an antidote for this drug. In contrast, medical professionals can quickly reverse the effects of heparin using protamine. This report details the selection of an aptamer to bivalirudin that functions as an antidote in buffer. This was accomplished by immobilizing the drug on a monolithic column to partition binding sequences from nonbinding sequences using a low-pressure chromatography system and salt gradient elution. The elution profile of binding sequences was compared to that of a blank column (no drug), and fractions with a chromatographic difference were analyzed via real-time PCR (polymerase chain reaction) and used for further selection. Sequences were identified by 454 sequencing and demonstrated low micromolar dissociation constants through fluorescence anisotropy after only two rounds of selection. One aptamer, JPB5, displayed a dose-dependent reduction of the clotting time in buffer, with a 20 µM aptamer achieving a nearly complete antidote effect. This work is expected to result in a superior safety profile for bivalirudin, resulting in enhanced patient care.</p> </div

Real-time PCR analysis of fractions from drug and blank disk.

<p>A) Round 1 analysis; B) Round 2 analysis.</p

Clotting studies with JPB5 and TV03 control.

<p>Clotting studies with JPB5 and TV03 control.</p

Probe Sequences.

<p>Probe Sequences.</p

AlphaScreen analysis of selection pools.

<p>AlphaScreen analysis of selection pools.</p

Discovery of Phenylaminopyridine Derivatives as Novel HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors

We identified a novel class of aryl-substituted triazine compounds as potent non-nucleoside reverse transcriptase inhibitors (NNRTIs) during a high-throughput screening campaign that evaluated more than 200000 compounds for antihuman immunodeficiency virus (HIV) activity using a cell-based full replication assay. Herein, we disclose the optimization of the antiviral activity in a cell-based assay system leading to the discovery of compound <b>27</b>, which possessed excellent potency against wild-type HIV-1 (EC₅₀ = 0.2 nM) as well as viruses bearing Y181C and K103N resistance mutations in the reverse transcriptase gene. The X-ray crystal structure of compound <b>27</b> complexed with wild-type reverse transcriptase confirmed the mode of action of this novel class of NNRTIs. Introduction of a chloro functional group in the pyrazole moiety dramatically improved hERG and CYP inhibition profiles, yielding highly promising leads for further development