ABSTRACT
Aim: The aim of the present study was to isolate, characterize and identify pathogenic bacteria from bacterial leaf spot infected grape vineyards of Maharashtra. Methodology: Collected diseased samples were subjected to isolation. All isolates were further subjected to different morphological and biochemical characterization. These isolates were also used to standardize inoculation methods to study host range and test pathogenicity to confirm infectivity. Genomic DNA was isolated from bacteria for phylogeneitc analysis using 16 rDNA. Results: The disease is characterized by water soaked, angular leaf spot which later turns to irregular, dark brown to black necrotic region on the leaf surface. Microbial studies confirmed that it is a Gram negative, rod shaped bacterium with white, mucoid, glistening and convex circular colonies on artificial medium. Pathogenicity test was performed to confirm virulence. Phylogenetic analysis of 16S rDNA gene exhibited more than 99% similarity with other Xanthomonas campestris pv. viticola. The bacterium was found resistant to vancomycin, peniciliin and oxacillin antibiotics. The bacterium is also capable of infecting Mangifera indica and Citrus limon along with eight weed species.
ABSTRACT
Objective: The main objective of the present study was to evolve a novel pharmacophore of methaniminium derivatives as factor Xa inhibitors by developing best 2D and 3D QSAR models. The models were developed for amino (3-((3, 5-difluoro-4-methyl-6-phenoxypyridine-2-yl) oxy) phenyl) methaniminium derivatives as factor Xa inhibitors. Methods: With the help of Marvin application, 2D structures of thirty compounds of methaniminium derivatives were drawn and consequently converted to 3D structures. 2D QSAR using multiple linear regression (MLR) analysis and PLS regression method was performed with the help of molecular design suite VLife MDS 4.3.3. 3D QSAR analysis was carried out using k-Nearest Neighbour Molecular Field Analysis (k-NN-MFA). Results: The most significant 2D models of methaniminium derivatives calculated squared correlation coefficient value 0.8002 using multiple linear regression (MLR) analysis. Partial Least Square (PLS) regression method was also employed. The results of both the methods were compared. In 2D QSAR model, T_C_O_5, T_2_O_2, s log p, T_2_O_1 and T_2_O_6 descriptors were found significant. The best 3D QSAR model with k-Nearest Neighbour Molecular Field Analysis have predicted q2 value 0.8790, q2_se value 0.0794, pred r2 value 0.9340 and pred_r2 se value 0.0540. The stepwise regression method was employed for anticipating the inhibitory activity of this class of compound. The 3D model demonstrated that hydrophobic, electrostatic and steric descriptors exhibit a crucial role in determining the inhibitory activity of this class of compounds. Conclusion: The developed 2D and 3D QSAR models have shown good r2 and q2 values of 0.8002 and 0.8790 respectively. There is high agreement in inhibitory properties of experimental and predicted values, which suggests that derived QSAR models have good predicting properties. The contour plots of 3D QSAR (k-NN-MFA) method furnish additional information on the relationship between the structure of the compound and their inhibitory activities which can be employed to construct newer potent factor Xa inhibitors.