Bio-gold nanoparticle synthesis by metalophilic bacterium Cupriavidus necator

Gold nanoparticles have potential applications in the areas of medicine, target drug delivery, cancer diagnosis and therapy, electronic, etc. Recently, biological system is considered as an environmental friendly method for synthesis of stable nanoparticles. We demonstrated a biological system for formation of stable gold nanoparticle by using Cupriavidus necator without using additives such as stabilizing agents. The sizes and composition of nanoparticles were characterised by UV-Vis spectrophotometer, transmission electron microscopy, energy dispersive spectra, and Image J software. Stable bio-gold nanoparticle was formed by using metalophilic bacterium Cupriavidus necator. High uniformity was observed in the presence of 1.55 mg/ml dry biomass, ImM Hydrogen tetrachloroaurate and 25 mM formate. Microbial synthesis of nanoparticle, such as gold, is an easy and eco-friendly method to preparation of stable nanoparticles

simple method for primary screening of antibacterial peptides in plant seeds

Regarding the importance of finding new antibacterial drugs, screening of plants as a promising resource are now conducted worldwide. In this study, we report the application of a simple previously described method for screening of different plant seeds in order to find the best resources of plant antimicrobial peptides. Total water soluble protein of 10 different plant seeds were extracted and subjected to SDS-PAGE and subsequent agar-overlay bioassays. Standard strains of Staphylococcus aureus, Enterococcus faecium and Escherichia coli were included in the bioassays. This method also was used for total proteins precipitated by Ammonium sulphate which ensure the protein nature of the test substances. Molecular size and the amounts of effective peptides were estimated using Tricin-SDS-PAGE and densitometry. Two different plant seeds showed noticeable antibacterial activities against tested Gram positive bacteria and a moderate inhibitory effect on Gram negative ones. Based on the results of Tricin-SDS-PAGE analysis which were carried out in parallel to bioassays, it was concluded that effective antibacterial substances are peptides with molecular weight of slightly larger than 5 kDa. On the basis of results of agar-overlay experiments and by screening of 10 different herbal seeds, we could introduce seeds of M. sativa L. and Onobrychis sativa Lam., as great sources of putative plant antibacterial peptides. The proposed screening method can be used for screening of large number of different plant seeds and even other parts of the plant body, regarding some necessary modification in total water soluble protein extraction steps