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This study reports the passive diffusion (in vitro) of silver nanoparticles (SNPs) and those of the amino acids tryptophan, phenylalanine, tyrosine across a biological membrane model. The experiments were carried out under physiological conditions at pH 7.4. Chicken egg shell outer membrane model was used to study the passive diffusion of the above materials. Passive diffusion was performed against and towards gravitation for 24 and 48 h. Fick's first law of diffusion was adopted for quantification of diffusion coefficient, permeability constant and diffusion rate. The egg shell membrane was characterized using scanning electron microscopy. The SNPs were synthesized by chemical degradation method and characterized by UV-visible spectroscopy and dynamic light scattering. An average size of nanoparticles obtained was 62 nm. The diffusion rates of amino acids were higher than those of SNPs. However, they were enhanced in their presence. Permeability coefficient and diffusion coefficient were higher for amino acids than SNPs. The possible mechanisms have been explained on the basis of molecular properties.

From the distinct wild locations of the Mumbai (India), dead Culex mosquito larvae were collected. The mid‐gut micro‐flora of these dead mosquito larvae was isolated on three different media that were selective for only the Gram‐positive bacteria. These bacteria were tested against the third instar stage of Culex quinquefasciatus larvae, cultured in the laboratory, for their larvicidal activity. After performing the toxicity assay four times in duplicates, the average statistical values showed four bacteria exhibiting differential toxicities. Identification of these strains was done by 16S rRNA sequencing and their respective surface morphologies were studied by scanning electron microscopy (SEM). The differential toxicities of the four identified Bacillus strains were rationalized by performing differential proteomics and metabolomics approach using LC‐MS and these results were analyzed against customized mosquito larvicidal toxin database which was further compared with the in silico p‐BLAST data of that respective Bacillus sp. from the NCBI database. The presence and significance of the various mosquitocidal toxins in the identified Bacillus sp. are elucidated. The present study also attempted to identify new bacterial species exhibiting mosquitocidal toxicities that have not been reported earlier.

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