Triadimenol and tebuconazole are potent inhibitors of the sterol 14 alpha-demethylation reaction in fungi which is catalysed by CYP51, a haem-thiolate containing enzyme belonging to the cytochrome P450 monooxygenase superfamily. Using CYP51 from the phytopathogen Ustilago maydis, a comparison of the sensitivity of the fungal enzyme to triadimenol and tebuconazole has been carried out. U. maydis CYP51 was purified to homogeneity as determined by SDS-PAGE and specific haem content. Catalytic activity was investigated following reconstitution with its respective NADPH cytochrome P450 reductase and proposed endogenous substrate, 24-methylenedihydrolanosterol. Addition of the triadimenol and tebuconazole induced type II spectral changes in the enzyme, with saturation occurring at equimolar azole concentrations. Inhibition of reconstituted activities showed a one-to-one sensitivity of the fungal CYP51 as judged by IC50 values. The implications for fungicide mode of action and treatment are discussed.
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http://dx.doi.org/10.1111/j.1574-6968.1998.tb13342.x | DOI Listing |
Talanta
February 2025
Department of Chemistry, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran.
A dispersive solid phase extraction method using new magnetic nanoparticles based on nickel ferrite was introduced for the extraction of six triazole pesticides (penconazole, hexaconazole, tebuconazole, diniconazole, triadimefon, and difenoconazole) from water samples before liquid chromatography-tandem mass spectrometry analyses. Initially, a new deep eutectic solvent was synthesized with 1,2,4-triazole and n-octanol for surface modification of the nanoparticles easily achieved through microwave radiation. The nanoparticles morphology, magnetic properties, adsorption capacity, isotherms, and crystalline patterns of the sorbent were examined.
View Article and Find Full Text PDFToxicol Sci
December 2024
Amsterdam Institute for Life and Environment, Section Environment and Health, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.
Pest Manag Sci
November 2024
College of Plant Protection, Shandong Agricultural University, Tai'an, People's Republic of China.
Background: Environmental microorganisms are major contributors to the development and spread of disease. Chemical disinfection can inhibit pathogens and play a preventive role against diseases. In agriculture, prolonging the floating time of chemical pesticides in the air has a positive effect on the control of airborne diseases.
View Article and Find Full Text PDFEnviron Int
July 2024
Product Safety, Syngenta Crop Protection LLC, Greensboro NC 27409, USA.
A significant challenge in the traditional human health risk assessment of agrochemicals is the uncertainty in quantifying the interspecies differences between animal models and humans. To work toward a more accurate and animal-free risk determination, new approaches such as physiologically based kinetic (PBK) modeling have been used to perform dosimetry extrapolation from animals to humans. However, the regulatory use and acceptance of PBK modeling is limited for chemicals that lack in vivo animal pharmacokinetic (PK) data, given the inability to evaluate models.
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