FT-IR study of the effect of zinc exposure on the biochemical contents of the muscle of Labeo rohita

Heavy metal pollution is a major environmental problem in the modern world due to increasing human activities. Zinc is an essential element involved in a wide variety of cellular processes. However, it becomes toxic when elevated concentrations are introduced into the environment. The goal of the present study is to investigate the effect of zinc exposure on the biochemical contents of the muscle tissues of freshwater species Labeo rohita using Fourier transform infrared (FT-IR) spectroscopy. Since the muscle constitutes the greatest mass of the fish that is consumed, the present study has paid particular attention to muscle component. The result reveals that the zinc exposure causes significant changes in the biochemical contents of the L. rohita muscle tissues. In addition, it causes an alteration in the protein secondary structures by decreasing the α-helix and increasing the β-sheet contents of muscle tissues. Further, it has been observed that the administration of chelating agent D-penicillamine improves the protein and lipid contents in the muscle tissues compared to zinc exposed tissues. This result shows that D-penicillamine is the effective chelator of zinc in reducing the body burden of L. rohita fingerlings.     

Intramolecular-Prins-cyclization: a novel synthesis of hexahydro-2H-furo[3,2-c]pyran derivatives

p-Toluenesulfonic acid is found to catalyze the coupling of (Z)-hex-3-ene-1,6-diol with a series of aldehydes by means of intramolecular-Prins-cyclization to provide the corresponding hexahydro-2H-furo[3,2-c]pyran derivatives in good yields with complete cis-selectivity, whereas the coupling of (E)-hex-3-ene-1,6-diol with aliphatic aldehydes gave trans-fused bicyclic furopyrans.     

Oxidative Prins and Prins/Friedel-Crafts cyclizations for the stereoselective synthesis of dioxabicycles and hexahydro-1H-benzo[f]isochromenes via the benzylic C-H activation

1-Benzyl ethers of (E)- and (Z)-hex-3-en-1,6-diols and hept-3-en-1,7-diols undergo a smooth oxidative cyclization with DDQ in the presence of In(OTf)(3) through a sequential C-H bond activation and an intramolecular Prins cyclization to afford the corresponding trans- and cis-fused hexahydro-2H-furo[3,2-c]pyrans and octahydropyrano[4,3-b]pyrans respectively in good yields with an excellent stereoselectivity. Aryl tethered homoallylbenzyl ethers such as benzyl ethers of (E)- and (Z)-6-arylhex-3-enyl alcohols undergo a tandem Prins/Friedel-Crafts cyclization in the presence of stoichiometric amounts of DDQ and SnCl(4)via the benzylic C-H bond activation to furnish the corresponding trans- and cis-fused hexahydro-1H-benzo[f]isochromenes in good yields with complete stereoselectivity.     

Facile backbone (1H, 15N, 13Ca,and 13C′) assignment of 13C/15N‐labeled proteins using orthogonal projection planes of HNN and HN(C)N experiments and its automation

Recently, we introduced an efficient high‐throughput protocol for backbone assignment of small folded proteins based on two‐dimensional (2D) projections of HN(C)N suite of experiments and its automation [Borkar et al., J. Biomol. NMR 2011, 50(3), 285–297]. This strategy provides complete sequence‐specific assignment of backbone (¹H, ¹⁵N, ¹³C^α, and ¹³C′) resonances in less than a day; thus, it has great implications for high‐throughput structural proteomics. However, in cases when such small folded protein exhibits substantial amide ¹H shift degeneracy (typically seen in alpha‐helical proteins), the strategy may fail or lead to ambiguities. Another limitation is with respect to the identification of checkpoints from the variants of 2D‐hncNH spectrum. For example, a protein with many GG, GA, AA, SS, TS, TT, and TS types of dipeptide stretches along its sequence, thus the identification of NH cross‐peak corresponding to second G, A, S, or T becomes difficult. In this backdrop, we present here two improvements to enhance the utility of the proposed high‐throughput AUTOmatic Backbone Assignment protocol: (i) use of 2D‐hNnH spectrum and its variants that display additional ¹H–¹⁵N correlations and thus help to resolve ambiguities arising because of amide ¹H shift degeneracy and (ii) optimization of the τ_CN delay in the 2D‐hncNH experiment that, when properly adjusted, is observed to help remove ambiguities in the identification of the checkpoints. These improvements have also been incorporated in the automation program AUTOmatic Backbone Assignment. Finally, the performance of the strategy and the automation has been demonstrated using the chicken SH3 domain protein. Copyright © 2012 John Wiley & Sons, Ltd.     

A New Markov Selection Procedure for Degenerate Diffusions

A new selection principle is proposed for construction of a Feller solution to an ill-posed degenerate diffusion process. This is based on constructing the Feller transition kernel from the unique (under suitable conditions) continuous viscosity solutions to the backward Kolmogorov equation associated with the diffusion. The connection of this Feller process with the small-noise limits of the nondegenerate perturbations of the diffusion and several other related phenomena are also discussed.     

Synthesis of gold nanoparticles using herbal Acorus calamus rhizome extract and coating on cotton fabric for antibacterial and UV blocking applications

Gold nanoparticles (AuNPs) have been synthesized by greener method using chloroauric acid as precursor and extract of Acorus calamus rhizome as reducing agent. Formation of AuNP was confirmed by the presence of Surface Plasmon Resonance (SPR) peak in UV–Visible spectral analysis. XRD and FT-IR spectral analyses were performed for characterization. SEM images show spherical morphology and HR-TEM images reveal nanosize of AuNPs. The AuNPs were then coated on cotton fabric by pad-dry-cure method and characterized by SEM with EDAX technique. The results reveal the deposition of AuNPs on the surface of cotton fabric. Uncoated cotton, neat extract coated cotton and extract containing AuNPs coated cotton fabrics were then tested for antibacterial activity against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacterial strains by AATCC 100 test method. It showed that the extract containing AuNPs coated cotton fabric had higher antibacterial activity than other test samples against E. coli. UV-DRS analysis performed on extract containing AuNPs coated cotton fabric showed improved UV-blocking property than uncoated cotton fabric and neat extract coated cotton fabric.