Biogenic Synthesis, Characterization and Antibacterial Properties of Silver Nanoparticles against Human Pathogens.

Biogenic synthesis of silver nanoparticles (AgNPs) is more eco-friendly and cost-effective approach as compared to the conventional chemical synthesis. Biologically synthesized AgNPs have been proved as therapeutically effective and valuable compounds. In this study, the four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the biogenic synthesis of AgNPs. Agar well diffusion assay revealed to determine the antibacterial activity of all biogenically synthesized AGNPs showed that P. aeruginosa AgNPs possessed significantly high (p < 0.05) antibacterial potential against all tested isolates. The one-way ANOVA test showed that that P. aeruginosa AgNPs showed significantly (p < 0.05) larger zones of inhibition (ZOI: 19 to 22 mm) compared to the positive control (rifampicin: 50 µg/mL) while no ZOI was observed against negative control (Dimethyl sulfoxide: DMSO). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) concentration against four test strains also showed that among all biogenically synthesized NPs, P. aeruginosa AgNPs showed effective MIC (3.3-3.6 µg/mL) and MBC (4.3-4.6 µg/mL). Hence, P. aeruginosa AGNPs were characterized using visual UV vis-spectroscopy, X-ray diffractometer (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The formation of peak around 430 nm indicated the formation of AgNPs while the FTIR confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). SEM revealed that the NPs were of approximately 40 nm. Overall, this study suggested that the biogenically synthesized nanoparticles could be utilized as effective antimicrobial agents for effective disease control.

Cloning and over Expression Studies of Ovine Somatotropin cDNA of Kajli (sheep breed) in a Prokaryotic System.

Genetic studies including the quest, cloning and expression of genes encoding proteins responsible for various vital physiological processes and beneficial characteristics of economic perspective have made the biotechnology research progressively auspicious. Due to its great zootechnical and industrial importance somatotropin gene have been cloned from various animal species. Current study was designed to clone mature ovine growth hormone complementary DNA (oGH cDNA) of a sheep breed, Kajli and carry out over expression studies of cloned GH cDNA in a suitable prokaryotic expression system. Sheep GH cDNA was cloned in T/A (thymine / adenine) vector with signal peptide and confirmed by nested polymerase chain reaction (PCR) and restriction digestion. The gene was then ligated in pLEX expression vector and restricted plasmids showed a fragment insert of ~ 600 bps. Restriction analysis confirmed positive clones, were induced for protein expression analysis. The pET vectors (plasmid for expression by T7 RNA polymerase) have an isopropylthio-ß-galactoside (IPTG) inducible strong T7 promoter and Escherichia coli expression strain of BL21 (DE3) pLysS contains DNA fragment from T7 phage which harbors RNA polymerase. Therefore, for expressing recombinant proteins, cells were induced with various IPTG concentrations to optimize expression levels. Cells were induced with different IPTG concentrations (0.1 to 0.8 mM) followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Results indicated maximum expression level of oGH at 5 hrs after induction of cells with 0.3 mM IPTG concentration with a molecular weight of 22 kDa. As for as cellular localization of protein is concerned accumulation of expressed oGH is observed in inclusion bodies. The successful expression of the cloned GH cDNA of sheep confirmed the functional viability of the clone. The above mentioned technique of genetic engineering has provided to boost the dairy industry by the production of large quantities of recombinant bovine somatotropin (rbST).