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We have studied the effect of phosphate capping on the high temperature thermal stability and magnetic properties of magnetite (Fe3O4) nanoparticles synthesized through a single-step co-precipitation method. The prepared magnetic nanoparticles are characterized using various techniques. When annealed in air, the phosphate capped nanoparticle undergoes a magnetic to non-magnetic phase transition at a temperature of 689 °C as compared to 580 °C in the uncoated nanoparticle of similar size. The observed high temperature phase stability of phosphate capped nanoparticle is attributed to the formation of a phosphocarbonaceous shell over the nanoparticles, which acts as a covalently attached protective layer and improves the thermal stability of the core material by increasing the activation energy. The phosphocarbonaceous shell prevents the intrusion of heat, oxygen, volatiles, and mass into the magnetic core. At higher temperatures, the coalescence of nanoparticles occurs along with the restructuring of the phosphocarbonaceous shell into a vitreous semisolid layer on the nanoparticles, which is confirmed from the small angle X-ray scattering, Fourier transform infra red spectroscopy, and transmission electron microscopy measurements. The probable mechanism for the enhancement of thermal stability of phosphocarbonaceous capped nanoparticles is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Enzymatic synthesis of α-32P and α-33P labelled deoxyribonucleotides involves the transfer of radiolabelled phosphorus from either γ-32P adenosine triphosphate (γ-ATP) or γ-32P guanosine triphosphate (γ-GTP). Subsequent removal of these ribonucleotides is essential for the preparation of chemically pure deoxyribonucleotides. Agarose-phenyl boronate columns, which bind specifically to cis-diol moieties, have been used for the removal of ribonucleotide contaminants. However, this involves column losses and additional radiation exposure. In the present work we describe a chemical method for the improvement of the chemical purity, based on the preferential oxidation of ribose sugars by periodate. The cis-diol moiety of ribose is specifically oxidised to the dialdehyde. The excess periodate ions were destroyed using ethylene glycol. The phosphate group was then cleaved by β-elimination using alkali. The product was purified using anion exchange chromatography. The efficiency of the process was validated using tracer γ-32P ATP and α-32P dATP. Samples at various steps were analysed by TLC, autoradiography and HPLC. During the process ATP is oxidised whereas 2′-deoxyadenosine triphosphate (dATP) remains intact. The α-32P dATP synthesized by this process was assayed for its incorporation in λ-DNA by the random priming method and was found to be effectively incorporated. The process developed is an efficient and convenient method for the preparation of chemically pure deoxyribonucleotides. [Copyright &y& Elsevier]

Background: In vitro , the molecular docking method has been suggested for estimating the biological affinity of the pharmacophores with physiologically active compounds. It is the latter stage in molecular docking, and the docking scores are examined using the AutoDock 4.2 tool program. The chosen compounds can be evaluated for in vitro activity based on the binding scores, and the IC 50 values can be computed., Objective: The purpose of this work was to create methyl isatin compounds as potential antidepressants, compute physicochemical characteristics, and carry out docking analysis., Methods: The protein data bank of the RCSB (Research Collaboratory for Structural Bioinformatics) was used to download the PDB structures of monoamine oxidase (PDB ID: 2BXR) and indoleamine 2,3-dioxygenase (PDB ID: 6E35). Based on the literature, methyl isatin derivatives were chosen as the lead chemicals. By determining their IC 50 values, the chosen compounds were tested for in vitro anti-depressant activity., Results: The binding scores for the interactions of SDI 1 and SD 2 with indoleamine 2,3 dioxygenase were found to be -10.55 kcal/mol and -11.08 kcal/mol, respectively, while the scores for their interactions with monoamine oxidase were found to be -8.76 kcal/mol and -9.28 kcal/mol, respectively, using AutoDock 4.2. The relationship between biological affinity and pharmacophore electrical structure was examined using the docking technique. The chosen compounds were tested for their ability to inhibit MAO, and the IC 50 values for each were found to be 51.20 and 56, respectively., Conclusion: This investigation has identified many novel and effective MAO-A inhibitors from the family of chemicals known as methyl isatin derivatives. Lead optimization was applied to the SDI 1 and SDI 2 derivatives. The superior bioactivity, pharmacokinetic profile, BBB penetration, pre-ADMET profiles, such as HIA (human intestinal absorption) and MDCK (Madin-Darby canine kidney), plasma protein binding, toxicity assessment, and docking outcomes, have been obtained. According to the study, synthesised isatin 1 and SDI 2 derivatives exhibited a stronger MAO inhibitory activity and effective binding energy, which may help prevent stress-induced depression and other neurodegenerative disorders caused by a monoamine imbalance., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Luciferase from Indian firefly Luciola praeusta (Coleoptera: Lampyridae: Luciolinae) was isolated and the properties compared with that of the North American firefly, Photinus pyralis. Luciola praeusta luciferase was purified using acetone extraction, gel-filtration column chromatography, ammonium sulfate precipitation and anion exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates a homogeneous preparation and the molecular mass was slightly higher than that of Photinus pyralis. The effect of pH, buffer composition and metal ions on the spectral characteristics was studied. The maximum bioluminescence activity of luciferase was observed in ACES buffer at pH 6.5. The emission maximum of 562 nm (in crude extract) was red shifted to 570 nm in Tricine buffer at pH 7.8. In addition, the effect of bovine serum albumin on the storage stability of the protein was investigated. Based on the unique spectral characteristics observed, we propose that Luciola praeusta luciferase in the native form is suitable for the assay of biochemical metabolites in acidic pH., (Copyright © 2013 John Wiley & Sons, Ltd.)

As a novel attempt for the intracellular recombinant protein over expression and easy purification from Pichia pastoris, the therapeutic cytokine human granulocyte macrophage colony stimulating factor (hGMCSF) gene was fused to an intein-chitin-binding domain (gene from pTYB11 vector) fusion tag by overlap extension PCR and inserted into pPICZB vector, allowing for the purification of a native recombinant protein without the need for enzymatic cleavage. The fusion protein under the AOX1 promoter was integrated into the P. pastoris genome (SMD 1168) and the recombinant Pichia clones were screened for multicopy integrants. Expression of hGMCSF was done using glycerol and methanol based synthetic medium by three stage cultivation in a bioreactor. Purification of the expressed hGMCSF fusion protein was done after cell disruption and binding of the solubilized fusion protein to chitin affinity column, followed by DTT induced on column cleavage of hGMCSF from the intein tag. In this study, final biomass of 89 g dry cell weight/l and purified hGMCSF of 120 mg/l having a specific activity of 0.657 x 10(7) IU/mg was obtained. This strategy has an edge over the other--His or--GST based fusion protein purification where non-specific protein binding, expensive enzymatic cleavage and further purification of the enzyme is required. It distinguishes itself from all other purification systems by its ability to purify, in a single chromatographic step.