ABSTRACT
Organophosphates constitute a major class of pesticides widely employed in agriculture to manage insect pests. Their toxicity is attributed to their ability to inhibit the functioning of acetylcholinesterase (AChE), an essential enzyme for normal nerve transmission. Organophosphates, especially chlorpyrifos, have been a key component of the integrated pest management (IPM) in onions, effectively controlling onion maggot Delia antiqua, a severe pest of onions. However, the growing concerns over the use of this insecticide on human health and the environment compelled the need for an alternative organophosphate and a potential microbial agent for bioremediation to mitigate organophosphate pesticide pollution. In the present study, chloropyrifos along with five other organophosphate insecticides, phosmet, primiphos-methyl, isofenphos, iodofenphos and tribuphos, were screened against the target protein AChE of D. antiqua using molecular modeling and docking techniques. The results revealed that iodofenphos showed the best interaction, while tribuphos had the lowest interaction with the AChE based on comparative binding energy values. Further, protein-protein interaction analysis conducted using the STRING database and Cytoscap software revealed that AChE is linked with a network of 10 different proteins, suggesting that the function of AChE is disrupted through interaction with insecticides, potentially leading to disruption within the network of associated proteins. Additionally, an in silico study was conducted to predict the binding efficiency of two organophosphate degrading enzymes, organophosphohydrolase (OpdA) from Agrobacterium radiobacter and Trichoderma harzianum paraoxonase 1 like (ThPON1-like) protein from Trichoderma harzianum, with the selected insecticides. The analysis revealed their potential to degrade the pesticides, offering a promising alternative before going for cumbersome onsite remediation.
ABSTRACT
Fusarium oxysporum f. sp. cubense is one of the most severe and threatening pathogens of bananas, causing "Panama wilt" worldwide. Confrontation assay of Foc antagonistic bacterial endophyte, Bacillus velezensis YEBBR6, with the Foc and GC-MS profiling of excised agar from the zone of inhibition, led to the unveiling of secondary metabolites produced by the endophyte. To refine the probable antifungal compounds among the numerous biomolecules formed during their di-trophic interaction with the pathogen, fungal protein targets were modeled, and docking studies (AutoDock Vina module of the PyRx 0.8 server) were done with all the compounds. Triamcinolone acetonide exhibited the most excellent affinity for the protein targets among the compounds studied. It had a maximum binding affinity of 11.2 kcal/mol for XRN2 (5' â 3'). Further, the protein-ligand complex formation kinetics was done through Molecular Dynamic Simulation studies. Graphs for the RMSD, RMSF, Rg, potential energy, and SASA were generated, and the values during the simulation period suggested the stability of the biomolecule as a complex with the protein. This indicated Triamcinolone acetonide's potential ability to act as a functional disrupter of the target protein and likely an antifungal molecule. Further, the biomolecule was tested for its activity against Foc by screening in the wet lab through the poisoned plate technique, and it was found to be fully inhibitory to the growth of the pathogen at 1000 ppm.
