Voltammetric Detection of a Specific DNA Sequence of Avian Influenza Virus H5N1 Using HS‐ssDNA Probe Deposited onto Gold Electrode

The working principle of a genosensor is based on the mechanism of ion‐channel mimetic sensors. The analytical signals generated upon hybridization processes were recorded by a redox active marker [Fe(CN)₆]^3?/4? present in the sample solution using voltammetric techniques. The developed genosensor was suitable for determination of 20‐mer complementary oligonucleotide sequence, and also of the PCR products containing the complementary 20‐mer sequence in various positions, with detection limits in the 10 pM range. The noncomplementary 20‐mer oligonucleotide sequence as well as the PCR product without complementary region generated very weak response. The good discrimination of the position of the complementary part in the PCR products was observed.     

Powerful connection of laccase and carbon nanotubes: Material for mediator-free electron transport on the enzymatic cathode of the biobattery

We describe the preparation of laccase/single-walled carbon nanotube bioconjugates, their application for the modification of electrodes and application of the electrodes as cathodes for the catalytic reduction of oxygen in a hybrid biofuel cell with Zn anode. Carbon nanotubes functionalized with aminoethyl residues, activated and reacted with laccase show high bioelectrocatalytic activity and are promising for the biofuel cell applications. The power density of the cell was 1 mW cm^− 2 at working voltage of 0.8 V. The open circuit voltage of this hybrid cell was as high as 1.5 V.     

Potent "clicked" MMP2 inhibitors: synthesis, molecular modeling and biological exploration

A new series of MMP2 inhibitors is described, following a fragment-based drug design approach. One fragment containing an azide group and a well known hydroxamate Zinc Binding Group in a α-sulfone, α-tetrahydropyrane scaffold, has been synthesized. Water-LOGSY, STD and competition-STD experiments indicate that this fragment binds to the active site of the enzyme. A click chemistry reaction was used to connect the azide to lipophilic alkynes selected to interact selectively with the S1' subunit of MMP2, as shown by docking and molecular dynamic experiments of the designed compounds. The most potent compounds 18 and 19 displayed an IC(50) of 1.4 and 0.3 nM against MMP2 respectively, and showed negligible activity towards MMP1 and MMP7, two metalloproteinases which have a shallow S1' subsite. Compound 18 also showed a promising selectivity profile against some antitarget metalloproteinases, such as MMP8, and considerably less activity against MMP14 (IC(50) = 65 nM), and MMP9 (IC(50) = 98 nM), other MMPs characterized by having a deep S1' pocket and, therefore, more similar to MMP2.     

Free-standing biomimetic polymer membrane imaged with atomic force microscopy

Fluid polymeric biomimetic membranes are probed with atomic force microscopy (AFM) using probes with both normal tetrahedrally shaped tips and nanoneedle-shaped Ag(2)Ga rods. When using nanoneedle probes, the collected force volume data show three distinct membrane regions which match the expected membrane structure when spanning an aperture in a hydrophobic scaffold. The method used provides a general method for mapping attractive fluid surfaces. In particular, the nanoneedle probing allows for characterization of free-standing biomimetic membranes with thickness on the nanometer scale suspended over 300-μm-wide apertures, where the membranes are stable toward hundreds of nanoindentations without breakage.     

LC-ESI-MS-MS Method for Monitoring Dopamine,Serotonin and Their Metabolites in Brain Tissue

A rapid and precise LC-ESI-MS-MS method for the parallel identification and quantification of dopamine, serotonin and their metabolites (homovanillic acid, 3-methoxytyramine, 3,4-dihydroxyphenylacetic acid and 5-hydroxyindolacetic acid) from rat brain tissue without any pre-analysis adjustment of the sample such as pre-concentration or derivatization has been developed. In particular, the reaction-monitoring mode was selected for its extremely high degree of selectivity and the stable-isotope-dilution assay for its high precision of quantification. Alternation the ionization polarity in the course of mass spectrometry detection enabled to determine substances susceptible to various ionization modes in only one analysis run. This fact, in combination with an easy pre-treatment step, constitutes the method straightforward and time undemanding. The developed method was characterized with a high precision (≤19.5%, determined as RSD), an acceptable accuracy (≥82.0%, determined as recovery), a low limit of detection (≤0.40 ng/100 mg brain tissue) and a low limit of quantification (≤0.42 ng/100 mg brain tissue). The method has been applied in a recent animal study. The levels of the studied neurotransmitters have been determined in the rat brain hippocampus, prefrontal cortex, and striatum in an animal model of schizophrenia induced by an acute dose of a dizocilpine.     

An efficient microwave assisted synthesis of novel class of Rhodanine derivatives as potential HIV-1 and JSP-1 inhibitors

(Z)-5-(2-(1H-Indol-3-yl)-2-oxoethylidene)-3-phenyl-2-thioxothiazolidin-4-one (7a-q) derivatives have been synthesized by the condensation reaction of 3-phenyl-2-thioxothiazolidin-4-ones (3a-h) with suitably substituted 2-(1H-indol-3-yl)-2-oxoacetaldehyde (6a-d) under microwave condition. The thioxothiazolidine-4-ones were prepared from the corresponding aromatic amines (1a-e) and di-(carboxymethyl)-trithiocarbonyl (2). The aldehydes (6a-h) were synthesized from the corresponding acid chlorides (5a-d) using HSnBu₃.     

Complete assignment of the 1H and 13C NMR spectra of garciniaphenone and keto-enol equilibrium statements for prenylated benzophenones

This article reports the structural elucidation by IR, UV and MS spectroscopic data along with 1H and 13C NMR chemical shift assignments of two benzophenones isolated from the fruit pericarp of Garcinia brasiliensis Mart. (Clusiaceae): garciniaphenone, (1R,5S,7S)-3-benzoyl-4-hydroxy-6,6-dimethyl-5,7-di(3-methyl-2-butenyl)bicyclo[3.3.1]non-3-ene-2,9-dione, a novel triprenylated benzophenone; and 7-epi-clusianone, a tetraprenylated benzophenone that has already been extracted from another species of the same family. Furthermore, the keto-enol tautomeric equilibrium at solution-state was described for these compounds by 1D and 2D NMR spectral methods and one attempt to rationalize the different ratios between the noted tautomers was based on stereochemical features.