Proteomic maps-toxicity relationship of halocarbons studied with similarity index and genetic algorithm

In this work we analyzed proteomic maps obtained from hepatocytes, which were treated with 14 halocarbons. A similarity index was introduced as a robust measure of similarity between two maps or between two selections of spots within the maps. A searching algorithm was used to identify the spots that may play an important role in toxicity mechanism. The highest correlation coefficients obtained between the similarity index and biological parameter were larger than 0.9.     

Chemical composition and In vitro antioxidant and antidiabetic activities of Eucalyptus Camaldulensis Dehnh. essential oil

The present study was designed to determine the composition of the essential oil of Eucalyptus camaldulensis Dehnh. leaves and to examine its in vitro antioxidant and antidiabetic activities. The chemical composition of the essential oil from Eucalyptus camaldulensis Dehnh. leaves was analyzed by GC/GC-MS, twenty-nine compounds representing 99.10% of the total oil were identified. The major components of the oil were p-cymene (68.43%), 1,8-cineole (13.92%), 1-(S)-α-pinene (3.45%) and R-(+)- limonene (2.84%). The antioxidant features of the essential oil were evaluated using inhibition of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and superoxide radicals, inhibition of hydrogen peroxide and lipid peroxidation assays. We also studied α-amylase and α-glucosidase inhibition in vitro to assess the antidiabetic properties of the essential oil. Both α-amylase and α-glucosidase were inhibited by a non-competitive mechanism.     

Synthesis of C2-symmetric bis-indolyl sulfones

A new class of C₂-symmetric bis-indole derivatives with 2,2′-linkage has been synthesized from bis-propargyl sulfones. The method involves treatment of the sulfones with catalytic amount of triethylamine to form the indole derivatives presumably via the intramolecular Michael addition to the intermediate bis-allenic sulfones. Interestingly, the expected Garratt-Braverman pathway was not followed.     

Stepwise O2-Induced Rearrangement and Disassembly of the [NiFe4(OH)(μ3-S)4] Active Site Cluster of CO Dehydrogenase

Ni,Fe-containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of carbon dioxide to carbon monoxide. CODHs are found in anaerobic microorganisms and can rapidly lose their activity when exposed to air. What causes the loss of activity is unclear. In this study, we analyzed the time-dependent structural changes induced by the presence of air on the metal centers of CODH-II. We show that inactivation is a multistep process. In a reversible step, the open coordination site on the Ni ion is blocked by a Ni,Fe-bridging μ-sulfido or chlorido ligand. Blocking this open coordination site with a cyanide ligand stabilizes the cluster against O₂-induced decomposition, indicating that O₂ attacks at the Ni ion. In the subsequent irreversible phase, nickel is lost, the Fe ions rearrange and the sulfido ligands disappear. Our data are consistent with a reversible reductive reactivation mechanism to protect CODHs from transient over-oxidation.     

Analytical method development for exploring pharmacokinetic profile of ursolic acid in rat tissues by high-performance thin-layer chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A simple and rapid high-performance thin-layer chromatographic (HPTLC) determination of ursolic acid (UA) in tissue is necessary...     

Snakes and perturbed random walks

We study some properties of random walks perturbed at extrema, which are generalizations of the walks considered, e.g., by Davis (1999) and Tóth (1996). This process can also be viewed as a version of an excited random walk, recently studied by many authors. We obtain several properties related to the range of the process with infinite memory and prove the strong law, the central limit theorem, and the criterion for the recurrence of the perturbed walk with finite memory. We also state some open problems. Our methods are predominantly combinatorial and do not involve complicated analytic techniques.