Novel application of fluorescence coupled capillary electrophoresis to resolve the interaction between the G-quadruplex aptamer and thrombin.

The dynamic binding status between the thrombin and its G-quadruplex aptamers and the stability of its interaction partners were probed using our previously established fluorescence-coupled capillary electrophoresis method. A 29-nucleic acid thrombin binding aptamer was chosen as a model to study its binding affinity with the thrombin ligand. First, the effects of the cations on the formation of G-quadruplex from unstructured 29-nucleic acid thrombin binding aptamer were examined.

Selective S-arylation of 2-oxazolidinethiones and selective N-arylation of 2-benzoxazolinones/2-benzimidazolinones.

There exist three possible patterns for the reaction of cyclic 2-oxazolidinethione and 2-benzoxazolidinethione with arynes, namely (a) S-arylation, (b) N-arylation, and (c) aryne insertion into the thiocarbonyl group (C[double bond, length as m-dash]S). Our studies demonstrate that S-arylation wins out affording S-aryl dihydrooxazoles. In contrast, for related reactions of cyclic 2-benzoxazolinone and 2-benzimidazolinone with arynes, it is found that N-arylation outcompetes O-arylation and aryne insertion into the C[double bond, length as m-dash]O group to give N-aryl 2-benzoxazolinones and N-aryl 2-benzimidazolinones.

Allosteric "beta-blocker" isolated from a DNA-encoded small molecule library.

The β-adrenergic receptor (βAR) has been a model system for understanding regulatory mechanisms of G-protein-coupled receptor (GPCR) actions and plays a significant role in cardiovascular and pulmonary diseases. Because all known β-adrenergic receptor drugs target the orthosteric binding site of the receptor, we set out to isolate allosteric ligands for this receptor by panning DNA-encoded small-molecule libraries comprising 190 million distinct compounds against purified human βAR. Here, we report the discovery of a small-molecule negative allosteric modulator (antagonist), compound 15 [([4-((2)-3-((()-3-(3-bromophenyl)-1-(methylamino)-1-oxopropan-2-yl)amino)-2-(2-cyclohexyl-2-phenylacetamido)-3-oxopropyl)benzamide], exhibiting a unique chemotype and low micromolar affinity for the βAR.

Evaluation of pharmacological relaxation effect of the natural product naringin on cultured airway smooth muscle cells and ovalbumin-induced asthma Balb/c mice.

Asthma has become a common chronic respiratory disease worldwide and its prevalence is predicted to continue increasing in the next decade, particularly in developing countries. A key component in asthma therapy is to alleviate the excessive bronchial airway narrowing ultimately due to airway smooth muscle contraction, which is often facilitated by a smooth muscle relaxant, such as the β-adrenergic agonists. Recently, bitter taste receptor (TAS2R) agonists, including saccharin and chloroquine, have been found to potently relax the airway smooth muscle cells (ASMCs) via intracellular Ca signaling.

Mesoporous hydroxyapatite nanoparticles hydrothermally synthesized in aqueous solution with hexametaphosphate and tea polyphenols.

Mesoporous hydroxyapatite (HA) nanoparticles with high surface area have been widely investigated for drug delivery. Herein we report a facile and simple strategy for the preparation of such materials using hexametaphosphate salt as inorganic phosphorus source. In the hydrothermal processing, hexametaphosphate plays an important role in the formation of mesoporous structure.

In-capillary probing of quantum dots and fluorescent protein self-assembly and displacement using Förster resonance energy transfer.

Herein, a Förster resonance energy transfer system was designed, which consisted of CdSe/ZnS quantum dots donor and mCherry fluorescent protein acceptor. The quantum dots and the mCherry proteins were conjugated to permit Förster resonance energy transfer. Capillary electrophoresis with fluorescence detection was used for the analyses for the described system.

Investigation of the weak binding of a tetrahistidine-tagged peptide to quantum dots by using capillary electrophoresis with fluorescence detection.

Capillary electrophoresis with fluorescence detection was utilized to probe the self-assembly between cyanine group dye labeled tetrahistidine containing peptide and CdSe/ZnS quantum dots, inside the capillary. Quantum dots and cyanine group dye labeled tetrahistidine containing peptide were injected into the capillary one after the other and allowed to self-assemble. Their self-assembly resulted into a measurable Förster resonance energy transfer signal between quantum dots and cyanine group dye labeled tetrahistidine containing peptide.

Investigation of multivalent interactions between conjugate of quantum dots with c-Myc peptide tag and the anti-c-Myc antibody by capillary electrophoresis with fluorescence detection.

Herein, we report an assay for detecting the binding of a multivalent peptide and antibody within a capillary with the use of fluorescence coupled capillary electrophoresis. Quantum dots and a c-Myc tag containing peptide EQKLISEEDLG H were injected sequentially and formed a multivalent quantum dot-EQKLISEEDLG H assembly within the capillary. The efficiency of the quantum dot-peptide self-assembly was affected by the peptide/quantum dot molar ratio, sampling time, and interval time.

Serum based fluorescent assay for evaluating dipeptidyl peptidase I activity in collagen induced arthritis rat model.

Dipeptidyl peptidase I (DPPI) is a lysosomal cysteine protease and derived from immune granule cells. It has been suggested playing an important role in the development of rheumatoid arthritis. In this study, a coumarin based fluorescent probe (GF-AFC) was designed and synthesized to evaluate DPPI activity in serum or tissue homogenates of collagen-induced arthritis (CIA) rats, an inflammatory arthropathy model.

Deposition of calcium phosphate coatings using condensed phosphates (P2O7(4-) and P3O10(5-)) as phosphate source through induction heating.

In present work condensed phosphates (P2O7(4-) and P3O10(5-)) were used as phosphate source in induction heating to deposit calcium phosphate coatings. The phase, morphology, and composition of different phosphate-related coatings were characterized and compared using XRD, FTIR, and SEM analyses. Results showed that P2O7(4-)formed calcium pyrophosphate hydrate coatings with interconnected cuboid-like particles.

Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling.

A capillary electrophoresis method to explore the self-assembly of a novel polypeptide ligand with quantum dots.

Polyhistidine peptides are effective ligands to coat quantum dots (QDs). It is known that both the number of histidine (His) residues repeats and their structural arrangements in a peptide ligand play important roles in the assembly of the peptide onto CdSe/ZnS QDs. However, due to steric hindrance, a peptide sequence with more than six His residue tandem repeats would hardly coordinate well with Zn(2+) in the QD shell to further enhance the binding affinity.

Developing a fluorescence-coupled capillary electrophoresis based method to probe interactions between QDs and colorectal cancer targeting peptides.

As is well known, quantum dots (QDs) have become valuable probes for cancer imaging. In particular, QD-labeled targeting peptides are capable of identifying cancer or tumors cells. A new colorectal cancer targeting peptide, cyclo(1, 9)-CTPSPFSHC, has strong targeting ability and also shows great potential in the identification and treatment of colon cancer.

Synthesis of porous starch xerogels modified with mercaptosuccinic acid to remove hazardous gardenia yellow.

Mercaptosuccinic acid (MSA) molecules were inserted into potato starch, leading to the breaking of intrinsic H-bonds within macromolecular chains of starch and the formation of intermolecular H-bonds between MSA and starch, which could be verified by Fourier transform infrared spectroscopy (FT-TR). MSA modified porous starch xerogels (PSX/MSA) were obtained after freeze-drying the MSA modified starch, and they were characterized by field emission scanning electron microscopy (FESEM), exhibiting the intriguing porous structure due to the separation of starch chains by MSA molecules. The PSX/MSA were then used as the adsorbents to remove gardenia yellow (GY), a natural colorant with genotoxicity.

Simultaneous detection of assembly and disassembly of multivalent HA tag and anti-HA antibody in single in-capillary assay.

Herein, we have developed an in-capillary assay for simultaneous detection of the assembly and disassembly of the multivalent HA tag peptide and antibody. HA tag with hexahistidine at C terminus (YPYDVPDYAG4 H6 , termed YPYDH6 ) was conjugated with quantum dots (QDs) by metal-affinity force to form a multivalent HA tag (QD-YPYDH6 ). QD-YPYDH6 and monoclonal anti-HA antibody (anti-HA) were sequentially injected into the capillary.

Simultaneous monitoring of quantum dots and their assembly and disassembly with PreScission protease using capillary electrophoresis with fluorescence detection.

A novel assay was developed for the simultaneous monitoring of quantum dots and their assembly and disassembly with PreScission protease using capillary electrophoresis with fluorescence detection. Quantum dots and PreScission protease were injected into a capillary sequentially, then mixed and assembled via a thioether bond upon coupling to glutathione S-transferase tag inside the capillary. The in-capillary assembly was influenced by the molar ratio and the time interval of injection.

One-Pot Conversion of N-Allyl-α-cyano Esters to α-Allyl-α-cyano Lactams through a Hydrolysis/Ketene Formation/Cyclization/Claisen Rearrangement Sequence.

An intramolecular ketene aza-Claisen rearrangement is developed for the first time to enable the stereoselective synthesis of α-ally-α-cyano-lactams from N-allyl amino esters. This reaction also exhibits outstanding chemoselectivity when an unsymmetrical bis-N-allyl group is present in the starting molecule. The usefulness of this method is demonstrated by a short synthesis of optically active bicyclolactam from l-proline.

Stereoselective Synthesis of Polycycles Containing an Aziridine Group: Intramolecular aza-Diels-Alder Reactions of Unactivated 2H-Azirines with Unactivated Dienes.

Vinyl azide with a pendent diene can undergo thermal decomposition to a related azirine intermediate, which was used immediately in an intramolecular aza-Diels-Alder reaction to furnish an aziridine-containing trans-fused tricyclic core structure with excellent stereoselectivity. The method provides a facile entry to complex polycyclic alkaliods which can be further elaborated by ring-opening reactions and ring expansion of the aziridine moiety, as well as by dihydroxylation of the alkene group.

Effects of the novel cis-nitromethylene neonicotinoid insecticide Paichongding on enzyme activities and microorganisms in yellow loam and Huangshi soils.

Soil enzyme activity and microbial population play important roles in maintaining soil fertility and ensure crop yield. Paichongding (IPP) is a novel cis-nitromethylene neonicotinoid insecticide, which was recently developed in China. In this study, in order to better understand IPP ecological toxicity, the impact of IPP on soil enzyme activity and microbial population in soils was investigated.

Facile synthesis of aza-spirocyclopropanyl oxindoles by the reaction of 3-(2-bromoethyl)-indole with 2,3-dimethylimidazole-1-sulfonyl azide triflate.

3-(2-Bromoethyl)indole reacts with 2,3-dimethylimidazole-1-sulfonyl azide triflate to give an intermediate N-(2,3-dimethylimidazole)-1-sulfonyl aza-spirocyclopropanyloxindole. This reactive species is captured by an alcohol or amine to afford the corresponding aza-spirooxindole sulfonate and sulfonamide.

QUANTITY: An Isobaric Tag for Quantitative Glycomics.

Glycan is an important class of macromolecules that play numerous biological functions. Quantitative glycomics--analysis of glycans at global level--however, is far behind genomics and proteomics owing to technical challenges associated with their chemical properties and structural complexity. As a result, technologies that can facilitate global glycan analysis are highly sought after.

In-capillary detection of fast antibody-peptide binding using fluorescence coupled capillary electrophoresis.

Herein, we report a technique for detecting the fast binding of antibody-peptide inside a capillary. Anti-HA was mixed and interacted with FAM-labeled HA tag (FAM-E4 ) inside the capillary. Fluorescence coupled capillary electrophoresis (CE-FL) was employed to measure and record the binding process.

Stereoselective Construction of Bridged trans-aza-Bicyclo[7/6,3/2,1]alkenyl Imines through Ring Expansion aza-Cope Rearrangement.

A highly stereoselective method for efficient synthesis of unprecedented bridged bicyclo[7/6,3/2,1]alkenyl amidines is described using cyclic N-allyl-aminoalkyne as a substrate. A ketenimine formation/cyclization/aza-Cope rearrangement cascade proceeds either with or without the aid of external DIPEA depending on substrate basicity. Fused bicycloamidines are also obtained via the same protocol using different N-allyl cyclic aminoalkynes.

Recombinant HE4 protein promotes proliferation of pancreatic and endometrial cancer cell lines.

Pancreatic adenocarcinoma is one of the most deadly malignancies, and endometrial cancer represents the most common gynecologic cancer in the USA. Better understanding on the pathologic mechanisms and pathways is required for effective treatment of these malignancies. Recently, human epididymis protein 4 (HE4 or WFDC2), a secretory glycoprotein, was found to be overexpressed in pancreatic and endometrial cancers.

In-capillary probing QDs and HAT tag self-assembly and displacement using Förster resonance energy transfer.

HAT tag, a natural His affinity tag, is one of the most popular fusion tags. However, HAT tag containing three positive charges limited its self-assembly with quantum dots (QDs). Herein, ATTO 590-labeled HAT peptide was synthesized to self-assemble with QDs inside the capillary.