Green synthesis of zinc oxide nanoparticles using flower extract of Nyctanthes arbor-tristis and their antifungal activity

Biological reduction agents are being explored worldwide to minimize the effects of toxic chemicals used in nanoparticle fabrication. The present study states a green approach for the synthesis of zinc oxide nanoparticles employing aqueous flower extract of Nyctanthes arbor-tristis. Flower extract was used as the biological reduction agent for synthesizing zinc oxide nanoparticles from zinc acetate dihydrate. Synthesis conditions were optimized for maximal and narrow size range synthesis of zinc oxide nanoparticles. The resultant nanopowder was characterized using various analytical techniques, such as UV–Visible spectroscopy, Fourier Transform Infrared spectroscopy, X-ray diffraction, Dynamic Light Scattering and Transmission Electron Microscopy. The nanopowder was stored in dried form and was found to be stable after 4 months. The size range of nanoparticles obtained upon synthesis at optimum conditions was 12–32 nm as reported by TEM. X-ray diffraction studies confirmed the crystalline nature of the nanoparticles indicating particle size within the range provided by electron microscopy data. Nanoparticles were tested for their antifungal potential and were found to be active against all five tested phytopathogens with lowest MIC value recorded as 16 μg/mL. Hence, an easy and effective green approach for synthesis of zinc oxide nanoparticles, with efficient antifungal potential is reported in this study. Keywords: Zinc oxide, Phytosynthesis, Electron microscopy, Optical techniques, Flower extract, Antifungal activit

Complete genome annotation data of Mycobacteriophages Prann and LeoAvram: New members of the family Siphoviridae

Two novel mycobacteriophages (Prann and LeoAvram) belonging to the family Siphoviridae were isolated from soil samples of Northern India. Genomic DNA of both the phages was extracted, and further sequenced using Illumina technology. Complete genome annotation of both the isolates was performed using DNA Master. Prann and LeoAvram had linear genomes of 68398bp and 47079bp, respectively, with G+C contents of 60-70%. A total of 99 and 75 ORFs were predicted in Prann and LeoAvram, respectively. Based on sequence similarity to known phage proteins, functions were assigned to 44 and 53 genes, respectively. These proteins could be classified into five major groups, viz., phage structural proteins, proteins for recombination, lytic enzymes, proteins involved in DNA / RNA metabolism, and in regulation. Mycobacterium smegmatis was used in this work as a safe surrogate for Mycobacterium tuberculosis, the causative agent for tuberculosis, a major infectious disease worldwide with developing antibiotic resistance. This is the first report of M. smegmatis phages from Northern India