Chitosan-encapsulated microbial biofertilizer: A breakthrough for enhanced tomato crop productivity.

Encapsulation technology protects the beneficial microorganisms, which are the sources of Nitrogen (N), Phosphorus (P), and Potassium (K), with a carrier material and improves the nutrient uptake from the soil. Pseudomonas fluorescens, gram-negative bacteria, was selected as the microorganism for encapsulation. A chitosan carrier (3 %), a polysaccharide, was chosen for the encapsulation of the bacterial strain to use as biofertilizers by standardization with two carriers, sodium alginate and chitosan. P. fluorescens encapsulated with chitosan showed a higher shelf life than sodium alginate. The shelf life of the encapsulated culture (7 × 1010 CFU/mL) was maintained for ten months. Studies were performed with the encapsulated P. fluorescens to analyze its nature and characteristics. The pot and field studies were conducted with the encapsulated P. fluorescens for the tomato crop. The difference between the treated and control plants was observed based on biometric parameters like shoot length and root length, fruit weight, and number of branches and fruits per plant. This study reveals that encapsulated P. fluorescens improved the yield of the crops. In addition, soil health and fertility were also enhanced. Thus, encapsulated P. fluorescens could be a superior solution for promoting soil health and crop productivity for sustainable agriculture.

Molecular docking and dynamic simulation studies of α4ß2 and α7 nicotinic acetylcholine receptors with tobacco smoke constituents nicotine, NNK and NNN.

Smoking constitutes a major global health problem. As it triggers various health hazards including cancers, cardiac and pulmonary illness, it is imperative to understand the mechanism of action of various smoke constituents on our cellular processes. Various in vitro studies have compiled the affinity of cigarette smoke constituents on various nicotinic acetylcholine receptors (nAChRs). But the nature of the intermolecular interactions contributing to this affinity and the key amino acids in the receptor active sites involved in this are not investigated so far. Here, we are examining the interaction of α7nAChR and α4ß2nAChR on nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosornicotine (NNN), the physiologically significant constituents in smoke, through molecular docking and dynamics simulations study. The docking of α4ß2nAChR structure with the ligands nicotine, NNK and NNN yielded docking scores of -41.45 kcal/mol, -59.28 kcal/mol and -54.60 kcal/mol, respectively, and that of α7nAChR receptor molecule with the ligands yielded docking scores of -59.54 kcal/mol, -71.06 kcal/mol and -70.86 kcal/mol, respectively. The study showed that NNK exhibited the highest affinity with the ligands which was confirmed by dynamics simulation. But higher stability of interactions as surmised from Molecular dynamics simulations was found for nicotine with α4ß2nAChR and NNN with α7nAChR. The findings validate the in vitro studies comparing the affinities of these compounds. The study will be useful in formulating effective nAChR agonists to treat neurological disorders and antagonists for smoke deaddiction and improve health standards.Communicated by Ramaswamy H. Sarma.

Green synthesis of silver nanoparticles using canthaxanthin from Dietzia maris AURCCBT01 and their cytotoxic properties against human keratinocyte cell line.

AIM: Nano-biotechnologically synthesizing silver nanoparticles via canthaxanthin pigment extracted from Dietzia maris AURCCBT01 and assessing their cytotoxic therapeutic potential against human keratinocyte cell line (HaCaT) were the key objectives of this study. METHODS AND RESULTS: The pigment extracted from D. maris AURCCBT01 was identified as canthaxanthin using UV-VIS spectroscopy, FTIR, NMR (1 H NMR and 13 C NMR) and MS. Canthaxanthin, treated with silver nitrate solution, produced canthaxanthin-mediated silver nanoparticles and they were characterized by UV-VIS spectroscopy, FTIR, XRD, FESEM-EDX and TEM-SAED techniques. UV-VIS spectroscopy pointed out an absorption band at 420 nm, relating to the surface plasmon resonance of silver nanoparticles. FTIR findings suggested that the diverse functional groups of canthaxanthin bio-molecules played a significant task in capping the silver nanoparticles. XRD analysis exhibited 40·20 nm for the crystal size of nanoparticles. FESEM and TEM exhibited that the biosynthesized silver nanoparticles were spherical in shape with crystalline nature and the particle size was 40-50 nm. Moreover, the cytotoxicity assessment of the synthesized nanoparticles in HaCaT revealed significant cytotoxicity in the cultured cells with an IC50 value of 43 µg ml-1 . CONCLUSION: Stable silver nanoparticles synthesized using canthaxanthin from D. maris AURCCBT01 were found effective for application in wound healing activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Biosynthesized silver nanoparticles via canthaxanthin bacterial pigment exhibited their cytotoxicity effect in HaCaT and testified their eventual therapeutic potential in the wound healing activity with no side effects in a cost effective and eco-friendly process.

ssDNA viruses: key players in global virome.

Single-stranded (ss)DNA viruses are extremely widespread, infect diverse hosts from all three domains of life and include important pathogens. Most ssDNA viruses possess small genomes that replicate by the rolling-circle-like mechanism initiated by a distinct virus-encoded endonuclease. High throughput genome sequencing and improved bioinformatics tools have yielded vast information on presence of ssDNA viruses in diverse habitats. The simple genome of ssDNA viruses have high propensity to undergo mutation and recombination often emerging as threat to human civilization. Interestingly their genome is found embedded in fossils dating back to million years. The unusual evolutionary history of ssDNA viruses reveal evidences of horizontal gene transfer, sometimes between different species and genera.