The white-rot fungus Phanerochaete chrysosporium was investigated for its capacity to degrade the herbicide diuron in liquid stationary cultures. The presence of diuron increased the production of lignin peroxidase in relation to control cultures but only barely affected the production of manganese peroxidase. The herbicide at the concentration of 7 μg/mL did not cause any reduction in the biomass production and it was almost completely removed after 10 days. Concomitantly with the removal of diuron, two metabolites, DCPMU [1-(3,4-dichlorophenyl)-3-methylurea] and DCPU [(3,4-dichlorophenyl)urea], were detected in the culture medium at the concentrations of 0.74 μg/mL and 0.06 μg/mL, respectively. Crude extracellular ligninolytic enzymes were not efficient in the in vitro degradation of diuron. In addition, 1-aminobenzotriazole (ABT), a cytochrome P450 inhibitor, significantly inhibited both diuron degradation and metabolites production. Significant reduction in the toxicity evaluated by the Lactuca sativa L. bioassay was observed in the cultures after 10 days of cultivation. In conclusion, P. chrysosporium can efficiently metabolize diuron without the accumulation of toxic products.

No abstract

No abstract

In this study, the antioxidant properties and the polyphenolic contents of raw and cooked pinhão seeds were evaluated. Four methods were used to evaluate the antioxidant activity: 1,1-diphenyl-2picrylhydrazyl free radical scavenging (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid scavenging (ABTS), ferrous ions chelating activity and lipid peroxidation inhibition (LPO). The EC 50 values (extract concentration producing 50% antioxidant effect), in μg/ml extract for raw and cooked extracts yielded respectively: DPPH, 870.7±30.8 and 112.6±5.4; ABTS, 170.7±7.8 and 52.1±2.1; ferrous ions chelating activity, 1,719±84.8 and 761±77.1; and LPO, 55.9±4.7 and 53.8±4.5. The improvement in the antioxidant activity in the cooked seeds can be attributed to the migration of polyphenolic compounds from coat to seed during cooking (5.92 ± 0.09 μg/mg and 24.06 ± 1.3 μg/mg in the raw and cooked seed extracts, respectively). Both raw and cooked seeds presented elevated amounts of catechin, 17.49±0.06 and 21.08±0.09 mg/100 g of seed, respectively.

Chemical group Common name Water solubility and persistence Chemical structure Phenoxy acetic 2,4 D 900 ppm 1 month 2,4,5 T 278 ppm 1 month Triazines Atrazine 33 ppm (22 o C) 5-7 months Ametryne 185 ppm (20 o C) 3-6 months Herbicides-Advances in Research 166 Chemical group Common name Water solubility and persistence Chemical structure Ureas Diuron 42 ppm 4-8 months tebuthiuron 2,500 ppm 12-15 months dinitroanilines Trifluralin 0.3 ppm 6 months acetanilides metolachlor 488 ppm (20 o C) 50 days isoxalone isoxaflutole 6 ppm (20 o C) 38 days Glycine derivative Glyphosate 15,700 ppm 30-90 days imidazolinones Imazapyr 11,272 ppm 3-6 months Involvement of Lignin-Modifying Enzymes in the Degradation of Herbicides