The interaction of metal oxide nanoparticles (NPs) with cells and lipid bilayers is precarious in various fields such as antibacterial and drug or gene delivery. These require a strong control over NPs-cell interactions, an understanding of how the NPs surface impact their interaction with lipid bilayers and cells. Therefore, to elucidate Titanium dioxide (TiO 2 ) NPs of size 8-10 nm and 90-100 nm and their interaction with lipid bilayer of Escherichia coli and Staphylococcus aureus, we studied membrane potential, membrane permeability. Results of the traditional method of checking antibacterial activity -minimum inhibitory concentration (MIC) was co-related with change in membrane potential and membrane permeability. TiO 2 NPs 8-10 nm have profound action on depolarization of membrane potential of E. coli cells, while of S. aureus were not affected. TiO 2 NPs 90-100 nm have very less effect on membrane potential and permeability of both organisms. It is observed that there exists a strong co-relation between antibacterial activity of the TiO 2 NPs and change in the membrane potential and membrane permeability. These observations are also supported by membrane leakage test by estimation of protein, deoxyribonucleic acid (DNA) and potassium ion (K + ) ion content.

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Pomegranate (Punica granatum) is an important exportable fruit crop of India that faces major losses when infected by fungal wilt and bacterial blight. The present investigation is aimed to isolate and identify the causative organism of the plant disease infecting the stem of pomegranate. The identification based on microscopic, morphological characterization and 18SrRNA sequencing confirms as Mariannaea elegans. The crude extracts of various leaves of plants viz Psidium guajava, Picrorhiza kurroa and Piper betel were used to evaluate antifungal activity using agar well diffusion method. Results confirm that ethanolic extract of Piper betel extract (0.5mg/ml) show zone of inhibition against Mariannea elegans. The research demonstrates that commonly used fungicides viz., Manocozeb/ Matalxy and Carbendazim showed very little inhibition as compared to the Piper betel ethanolic extracts and hence the latter proves to be a better and eco-friendlier control alternative. The present study was also aimed at finding remedies for bacterial blight. The blight pathogen was isolated from the fruit pericarp and identified using morphological and biochemical characters to be Xanthomonas axonopodis pv. punicae (Xap). Nanoparticles synthesized using green method, Copper oxide nanoparticles (1mg/ml) synthesized using Azadirachta indica leaf extract showed excellent inhibitory effect against the blight pathogen as compared to Bordeaux mixture, commonly used as an antimicrobial spray by farmers.