Enhanced Production of Phenolic Compounds in Compact Callus Aggregate Suspension Cultures of Rhodiola imbricata Edgew.

Applied Biochemistry and Biotechnology - Rhodiola imbricata is a rare medicinal plant of the trans-Himalayan region of Ladakh. It is used for the treatment of numerous health ailments. Compact...     

Aligned nanogold assisted one step sensing and removal of heavy metal ions

We depict a novel strategy exploiting the chemistry of metal ion adsorption for detection and sequestration of toxic heavy metal from processed water using gold nanoparticles capped with 4-aminothiophenol. The interaction between 4-aminothiophenol capped gold nanoparticles and heavy metal ions was studied as a function of time and concentration using TEM, HRTEM, SEM, EDS, and I-V characterization. Experiments confirmed that pH is one of the crucial controlling parameters. Adsorption capacity was monitored using AAS, UV-vis spectroscopy and I-V measurement. In the absence of any alloy formation between Au and heavy metal ions, the desorption of the heavy metal ions from 4-aminothiophenol capped gold nanoparticles surface by pH modulation serves as a mean of collection of heavy metal ions. Experiments revealed that the concentration of heavy metal ions in processed water after adsorption is below the maximum permissible limit set by the WHO.     

Self-nanoemulsifying drug delivery system for adefovir dipivoxil: Design, characterization, in vitro and ex vivo evaluation

Adefovir dipivoxil (ADV) is an anti-viral drug having low bioavailability due to low permeability and pH dependent solubility. In this study, self-nanoemulsifying drug delivery systems (SNEDDS) of ADV were developed with the objective of increasing its bioavailability by enhancing its intestinal permeability and minimizing the effect of pH. Preliminary screening was carried out to select oil, surfactant and co-surfactant. Ternary phase diagrams were constructed to identify the area of nanoemulsification. The nanoemulsion system selected from the phase diagram was transformed into solid-SNEDDS (S-SNEDDS) by lyophilization using D-mannitol as cryoprotectant. The formulations were characterized for transmittance, globule size, polydispersity index, zeta potential, cloud point, robustness to dilution, effect of pH and temperature, microscopic properties, in vitro and ex vivo drug release parameters. The liquid SNEDDS (L-SNEDDS) showed mean globule size of 110 ± 10 nm while mean globule size of 150 ± 16 nm was obtained with S-SNEDDS. The formulations were found to be robust to dilution and showed cloud point at 80-85 °C. TEM and SEM studies of nanoemulsion reconstituted from S-SNEDDS demonstrated the spherical shape and size of the globules. Results of DSC and XRD studies confirmed that the drug was incorporated in the S-SNEDDS. No significant difference was observed in the globule size within physiological variations of pH and temperature. The in vitro and ex vivo drug release from ADV SNEDDS was found to be significantly higher in comparison to that from plain drug suspension, irrespective of pH. Thus, SNEDDS were found to be instrumental in reducing the effect of pH variability of ADV and improving the release performance of ADV, indicating their potential to improve the oral bioavailability and thus the therapeutic efficacy of ADV.     

Agrobacterium-Mediated Gene Transfer in Plants and Biosafety Considerations

Agrobacterium, the natures?? genetic engineer, has been used as a vector to create transgenic plants. Agrobacterium-mediated gene transfer in plants is a highly efficient transformation process which is governed by various factors including genotype of the host plant, explant, vector, plasmid, bacterial strain, composition of culture medium, tissue damage, and temperature of co-cultivation. Agrobacterium has been successfully used to transform various economically and horticulturally important monocot and dicot species by standard tissue culture and in planta transformation techniques like floral or seedling infilteration, apical meristem transformation, and the pistil drip methods. Monocots have been comparatively difficult to transform by Agrobacterium. However, successful transformations have been reported in the last few years based on the adjustment of the parameters that govern the responses of monocots to Agrobacterium. A novel Agrobacterium transferred DNA-derived nanocomplex method has been developed which will be highly valuable for plant biology and biotechnology. Agrobacterium-mediated genetic transformation is known to be the preferred method of creating transgenic plants from a commercial and biosafety perspective. Agrobacterium-mediated gene transfer predominantly results in the integration of foreign genes at a single locus in the host plant, without associated vector backbone and is also known to produce marker free plants, which are the prerequisites for commercialization of transgenic crops. Research in Agrobacterium-mediated transformation can provide new and novel insights into the understanding of the regulatory process controlling molecular, cellular, biochemical, physiological, and developmental processes occurring during Agrobacterium-mediated transformation and also into a wide range of aspects on biological safety of transgenic crops to improve crop production to meet the demands of ever-growing world??s population.     

Theoretical study on the hydrogen bonding of five-membered heteroaromatics with water

The hydrogen-bonding ability of five-membered heteroaromatic molecules containing one chalcogen and two heteroatoms with nitrogen in addition to chalcogen, respectively, have been analyzed using density functional and molecular orbital methods through adduct formation with water. The stabilization energies for all the adducts are established at B3LYP/6-31+G* and MP2/6-31+G* levels after correcting for the basis set superposition error by using the counterpoise method and also corrected for zero-point vibrational energies. A natural bond orbital analysis at B3LYP/6-31+G* level and natural energy decomposition analysis at HF/6-31+G* using MP2/6-31+G* geometries have been carried out to understand the nature of hydrogen-bonding interaction in monohydrated heterocyclic adducts. Nucleus-independent chemical shift have been evaluated to understand the correlation between hydrogen bond formation and aromaticity.     

Vibrational dynamics of poly(L‐histidine)

Normal mode analysis and their dispersion for poly(L ‐histidine) (PLH) are reported by using Urey Bradley force field and Fourier Transform IR PLH exists in the α helical form. There are 17 atoms in one residue, which gives rise to 51 dispersion curves. To simplify, it is convenient to discuss the normal frequencies under three separate heads namely amide modes, side chain modes, and mixed mode. The calculated frequencies are found to be in reasonably good agreement with the Fourier Transform IR spectra. There exists exchange of character, attraction, and repulsion for selective dispersion curves with change in the phase value. Contributions to the heat capacity were calculated separately for the side chain, backbone, and mixed modes. The major contribution comes from the side chain and mixed modes. The sum of these three contributions gives the total heat capacity, which is in agreement with the reported experimental value. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 128–137, 2010     

Enhancement of lipase activity in non-aqueous media upon immobilization on multi-walled carbon nanotubes

Background  

Immobilization of biologically active proteins on nanosized surfaces is a key process in bionanofabrication. Carbon nanotubes with their high surface areas, as well as useful electronic, thermal and mechanical properties, constitute important building blocks in the fabrication of novel functional materials.     

DNA binding and topoisomerase II inhibitory activity of water-soluble ruthenium(II) and rhodium(III) complexes

Water-soluble piano-stool arene ruthenium complexes based on 1-(4-cyanophenyl)imidazole (CPI) and 4-cyanopyridine (CNPy) with the formulas [(eta6-arene)RuCl2(L)] (L = CPI, eta6-arene = benzene (1), p-cymene (2), hexamethylbenzene (3); L = CNPy, eta6-arene = benzene (4), p-cymene (5), hexamethylbenzene (6)) have been prepared by our earlier methods. The molecular structure of [(eta6-C6Me6)RuCl2(CNPy)] (6) has been determined crystallographically. Analogous rhodium(III) complex [(eta5-C5Me5)RhCl2(CPI)] (7) has also been prepared and characterized. DNA interaction with the arene ruthenium complexes and the rhodium complex has been examined by spectroscopic and gel mobility shift assay; condensation of DNA and B-->Z transition have also been described. Arene ruthenium(II) and EPh3 (E = P, As)-containing arene ruthenium(II) complexes exhibited strong binding behavior, however, rhodium(III) complexes were found to be Topo II inhibitors with an inhibition percentage of 70% (7) and 30% (7a). Furthermore, arene ruthenium complexes containing polypyridyl ligands also act as mild Topo II inhibitors (10%, 3c and 40%, 3d) in contrast to their precursor complexes. Complexes 4-6 also show significant inhibition of beta-hematin/hemozoin formation activity.     

A Versatile Approach for the Site‐Specific Modification of Recombinant Antibodies Using a Combination of Enzyme‐Mediated Bioconjugation and Click Chemistry

A unique two‐step modular system for site‐specific antibody modification and conjugation is reported. The first step of this approach uses enzymatic bioconjugation with the transpeptidase Sortase A for incorporation of strained cyclooctyne functional groups. The second step of this modular approach involves the azide–alkyne cycloaddition click reaction. The versatility of the two‐step approach has been exemplified by the selective incorporation of fluorescent dyes and a positron‐emitting copper‐64 radiotracer for fluorescence and positron‐emission tomography imaging of activated platelets, platelet aggregates, and thrombi, respectively. This flexible and versatile approach could be readily adapted to incorporate a large array of tailor‐made functional groups using reliable click chemistry whilst preserving the activity of the antibody or other sensitive biological macromolecules.