Mycodegradation of diazinon pesticide utilizing fungal strains isolated from polluted soil.

The current study aimed to isolate biodegradable soil fungi capable of metabolizing diazinon. The collected soil samples were investigated for diazinon pollution to detect the pesticide level in the polluted soil samples. Food poisoning techniques were utilized to preliminary investigate the biodegradation efficiency of the isolated fungal strains to diazinon pesticide using solid and liquid medium and also to detect their tolerance to different concentrations. GC-MS analysis of control and treated flasks were achieved to determine the diazinon residues for confirmation of the biodegradation efficiency. The total diazinon residues in the collected soil samples was found to be 0.106 mg/kg. Out of thirteen fungal strains isolated form diazinon polluted soils, six strains were potentially active in diazinon biodegradation. Food poisoning technique showed that A. niger, B. antennata, F. graminearum, P. digitatum, R. stolonifer and T. viride strains recorded fungal growth diameters of 65.2 ± 0.18, 57.5 ± 0.41, 47.2 ± 0.36, 56.5 ± 0.27, 85.0 ± 0.01, 85.0 ± 0.06 mm respectively in the treated group which were non significantly different compared to that of control (P > 0.05), indicating the high efficiency of these strains in diazinon degradation compared to the other isolated strains. GC-MS analysis revealed that B. antennata was the most efficient strain in diazinon degradation recording 32.24 ± 0.15 ppm concentration after 10 days incubation. Linear regression analysis confirmed that B. antennata was the most effective biodegradable strain recording the highest diazinon dissipation (83.88%) with the lowest T1/2 value of 5.96 days while T. viride, A. niger, R. stolonifer and F. graminearum exhibited a high biodegradable activities reducing diazinon to 80.26%, 78.22%, 77.36% and 75.43% respectively after 10 days incubation. In conclusion, these tolerant fungi could be considered as promising, eco-friendly and biodegradable fungi for the efficient and potential removal of hazardous diazinon from polluted soil.

Synthesis of novel benzopyran-connected pyrimidine and pyrazole derivatives via a green method using Cu(ii)-tyrosinase enzyme catalyst as potential larvicidal, antifeedant activities.

A series of benzopyran-connected pyrimidine (1a-g) and benzopyran-connected pyrazole (2a-i) derivatives were synthesized via Biginelli reaction using a green chemistry approach. Cu(ii)-tyrosinase was used as a catalyst in the synthesis of compounds 1a-g and 2a-ivia the Biginelli reaction. The as-synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectroscopy, and elemental analysis. The as-synthesized compounds were screened for larvicidal and antifeedant activities. The larvicidal activity was evaluated using the mosquito species Culex quinquefasciatus, and the antifeedant activity was evaluated using the fishes of Oreochromis mossambicus. The compounds 2a-i demonstrated lethal effects, killing 50% of second instar mosquito larvae when their LD50 values were 44.17, 34.96, 45.29, 45.28, 75.96, and 28.99 µg mL-1, respectively. Molecular docking studies were used for analysis based on the binding ability of an odorant binding protein (OBP) of Culex quinquefasciatus with compound 2h (binding energy = -6.12 kcal mol-1) and compound 1g (binding energy = -5.79 kcal mol-1). Therefore, the proposed target compounds were synthesized via a green method using Cu(ii)-enzyme as a catalyst to give high yield (94%). In biological screening, benzopyran-connected pyrazole (2h) was highly active compared with benzopyran-connected pyrimidine (1a-g) series in terms of larivicidal activity.