Publications by authors named "Venkatesh Perumal"

BS2 was isolated from meongge (common sea squirt) jeotgal, a Korean fermented seafood, and produces a bacteriocin, BacBS2, which strongly inhibits and . BacBS2 was partially purified by Q-Sepharose column chromatography after ammonium sulfate precipitation of the culture supernatant, then further purified by Sephadex G-50 column chromatography. Partially purified BacBS2 was estimated to be 6.

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In this present study, a gene (ent-B) encoding the bacteriocin enterocin-B was cloned, overexpressed and purified from Enterococcus faecium por1. The molecular weight of the bacteriocin enterocin-B was observed around 7.2 kDa and exhibited antimicrobial activity against several human pathogenic bacteria.

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Lactobacillus mucosae strain AN1 isolated from sheep milk and characterized for its probiotic suitability. In vitro evaluation of critical gut endurance properties of this strain were assessed by different screening methods such as bile salt, gastric acid, lysozyme tolerance assays, hemolytic, cholesterol reduction properties, and HT-29 cell line adhesion assay. Antibacterial peptide from this strain was purified using ammonium sulphate precipitation, gel filtration chromatography and reverse-phase HPLC.

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A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine-SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.

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Some 1,2-disubstituted benzimidazole derivatives (1-6) have been synthesized and characterized by mass, (1)H, (13)C NMR and elemental analysis. XRD analysis was carried out for 1-(4-methylbenzyl)-2-p-tolyl-1H-benzo[d]imidazole. Calculated bond lengths, bond angles and thus dihedral angles are found to be slightly higher than that of X-ray diffraction values of its experimental data.

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The interaction between a trifluoromethyl substituted imidazole derivative 2-(4-(trifluoromethyl)phenyl)-1-phenyl-1H-imidazo[4,5-f] [1,10] phenanthroline (tfmppip) and bovine serum albumin (BSA) was investigated by solution spectral studies. The observed experimental result shows that the imidazole derivative has strong ability to quench the fluorescence of BSA by forming complex which is stabilized by electrostatic interactions. The effective quenching constants (k(sv)) were 2.

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The synthesized imidazole derivative 2-(2,4-difluorophenyl)-1-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (dfpmpip) has been characterized using IR, mass, (1)H, (13)C NMR and elemental analysis. The photophysical properties of dfpmpip have been studied using UV-visible and fluorescence spectroscopy in different solvents. The solvent effect on the absorption and fluorescence bands has been analyzed by a multi-component linear regression.

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Phenanthrimidazole ligands with potential electron withdrawing trifluoromethyl substituent have been synthesized and characterized using IR, mass and NMR spectral studies. The effect of solvent on their absorption and emission have been analysed in detail by Kamlet-Taft Catalan approach. The introduction of trifluoromethyl substituent results in a significant blue shift in emission when compared to its parent compound.

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Phosphorescence studies of a series of heteroleptic cyclometalated iridium(III) complexes have been carried out. From the photoluminescent properties, it was found that these complexes possess dominantly (3)MLCT and (3)π-π* excited states. The solvent shifts are interpreted in terms of Reichardt-Dimroth solvent E(T) parameters and Marcus theory.

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Bioactive imidazole derivatives were synthesized and characterized by spectral techniques. The photophysical properties of imidazole derivatives were studied in several solvents. The observed spectral shift is attributed to a loss of planarity in the excited state provided by the non-co-planarity of the aryl rings attached to C(2) and N(1) atoms of the imidazole ring.

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Phosphorescent studies of 2-arylimidazole heteroleptic cyclometalated iridium(III) complexes with picolinic acid as the ancillary ligand were made. The observed experimental data reveal that these complexes possess dominantly (3)MLCT and (3)π-π* excited states and the solvent shift of these complexes is interpreted by Reichardt-Dimroth and Marcus solvent functions. The results are consistent with prior assignments on the absorption band to a metal-to-ligand charge transfer excited state associated with chelating ligand.

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In the title compound, C(25)H(15)FN(4)·H(2)O, the fused ring system is essentially planar [maximum deviation of 0.0822 (14) Å]. The imidazole ring makes dihedral angles of 76.

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Some novel Y-shaped imidazole derivatives were developed and characterized by NMR and mass spectral techniques. The photophysical properties of these imidazole derivatives were studied in several solvents. The Kamlet-Taft and Catalan's solvent scales were found to be the most suitable for describing the solvatochromic shifts of the absorption and fluorescence emission.

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Novel imidazole derivatives were synthesized and its crystal structure has been studied by single crystal XRD analysis. The photophysical properties of these imidazole derivatives were studied in several solvents, which include a wide range of apolar, polar and protic media. The observed lower fluorescence quantum yield may be due to an increase in the non-radiative deactivation rate constant.

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In the title compound, C(25)H(16)N(4), the fused ring system is essentially planar [maximum deviation = 0.1012 (15) Å]. The imidazole ring makes dihedral angles of 77.

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Bioactive imidazole derivatives were synthesized and characterized by NMR spectra, mass and CHN analysis. An excited state intramolecular proton transfer (ESIPT) process in hydroxy imidazole has been studied using emission spectroscopy. In hydrocarbon solvent, the tautomer emission predominates over the normal emission and in alcoholic solvent like ethanol; a dramatic enhancement of normal emission is observed which was due to increased solvation.

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The interaction between bioactive imidazole derivative (PPP) and bovine serum albumin (BSA) was investigated using fluorescence and UV-vis spectral studies. The experimental results showed that the fluorescence quenching of BSA by imidazole derivative was the result of the formation of BSA-PPP complex and the effective quenching constants (K(SV)) were 2.66×10(4), 2.

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2-(4-fluorophenyl)-1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole (fpmpdi) was synthesised and its structure was characterized by 1H, 13C, mass, elemental analysis and X-ray techniques. It belongs to monoclinic crystal system having the lattice dimensions of monoclinic with point group, P21/c; a=8.5132 (1) Å, b=9.

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