We have studied the direct electrochemistry of horseradish peroxidase (HRP) coupled to gold nanoparticles (AuNP) using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i) glutathione and (ii) lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications.

Magnetic shielding constants were calculated for the synthetic deoxyribonucleic acid (DNA) double helix poly(dG-dC).poly(dG-dC) from the x, y, and z coordinates of Z-DNA of Rich and co-workers [Wang, A. H-J., Quigley, G. J., Kolpak, F. J., Crawford, J. L., van Boom, J. H., van der Marel, G., & Rich, A. (1979) Nature (London) 282, 680-686)] and B-DNA of Arnott & Hukins [Arnott, S., & Hukins, D. W. L. (1972) Biochem. Biophys. Res. Commun. 47, 1504-1509], taking into account the contribution to shielding from ring current effects and effects from the diamagnetic and paramagnetic components of the atomic magnetic anisotropy. Comparison of the calculated shielding values with the experimentally observed nuclear magnetic resonance shift data for poly(dG-dC).poly(dG-dC) in high salt solution shows striking agreement for Z-DNA and considerable deviation for B-DNA, indicating that this synthetic DNA double helix is high salt solution can assume the spatial configuration of the left-handed Z-DNA double helix known to occur in crystals.

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Nanomaterials exhibit unique physical and chemical properties and, hence, they have received much attention from scientists and researchers in different areas of environmental sciences, specifically in bioremediation. Bioremediation provides a good clean-up strategy for some types of waste, but as it is expected, it will not be useful for all. For example, bioremediation may not provide a feasible strategy at sites with high concentrations of chemicals that are toxic to most microorganisms. These include heavy metals and salt. Further, the advancement in science and technology has increased standard of living which directly or indirectly contributes to the increase in waste and toxic material. Therefore, the remediation of contaminants by use of existing technology is not effective and efficient in cleaning up the environment. Hence, nanomaterials may be applied for bioremediation, which will not only have less toxic effect on microorganisms, but will also improve the microbial activity of the specific waste and toxic material which will reduce the overall time consumption as well as reduce the overall cost. In this paper we have briefly summarized the major types of nanomaterials that have been used so far in bioremediation of waste and toxic materials.

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The intimate details of the conformational features and dynamics of the trinucleoside diphosphates CpCpA and ApCpC in aqueous solution have been arrived at by the complete analysis of their proton magnetic resonance spectra. In addition to the right-handed stacked species in which the phosphodiester torsions conform to the gauche-gauche domains, sugar puckers 3E, C4'-C5 approximately equal to 60 degrees, C5'-O5' approximately 180 degrees, C3'-O3' approximately equal to 205 degrees, and chi CN approximately equal to 40 degrees, the trimers display a variety of spatial configurations, an important one being a bulged configuration in which the central nucleotide unit is bulged out, enabling stacking interactions between the end units. It is further shown that the 3' acceptor end of tRNA, CpCpA, displays considerable flexibility for the terminal adenine nucleotide unit. Theoretical NMR calculations demonstrate that the predominant solution conformation does not conform to the CCA terminus of tRNA as reported by four independent crystallographic studies of tRNAPhe. It is shown that the preferred intramolecular order of CCA in solution is such that chi 1 = chi 2 = chi 3 = 40 degrees, all the three sugars are in 3E, psi 1 = psi 2 = psi 3 = 60 degrees, phi 2 and phi 3 = 170 and 180 degrees, respectively, phi 1 = phi 2' = 205 degrees, and omega 1/omega 1 and omega 2/omega 2' = 240/205 degrees and 295/265 degrees, respectively.