The soil actinobacteria Rhodococcus rhodochrous PA-34, Rhodococcus sp. NDB 1165 and Nocardia globerula NHB-2 grown in the presence of isobutyronitrile exhibited nitrilase activities towards benzonitrile (approx. 1.1-1.9 U mg(-1) dry cell weight). The resting cell suspensions eliminated benzonitrile and the benzonitrile analogues chloroxynil (3,5-dichloro-4-hydroxybenzonitrile), bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) and ioxynil (3,5-diiodo-4-hydroxybenzonitrile) (0.5 mM each) from reaction mixtures at 30 degrees C and pH 8.0. The products were isolated and identified as the corresponding substituted benzoic acids. The reaction rates decreased in the order benzonitrile > chloroxynil > bromoxynil > ioxynil in all strains. Depending on the strain, 92-100, 70-90 and 30-51% of chloroxynil, bromoxynil and ioxynil, respectively, was hydrolyzed after 5 h. After a 20-h incubation, almost full conversion of chloroxynil and bromoxynil was observed in all strains, while only about 60% of the added ioxynil was converted into carboxylic acid. The product of ioxynil was not metabolized any further, and those of the other two herbicides very slowly. None of the nitrilase-producing strains hydrolyzed dichlobenil (2,6-dichlorobenzonitrile). 3,5-Dibromo-4-hydroxybenzoic acid exhibited less inhibitory effect than bromoxynil both on luminescent bacteria and germinating seeds of Lactuca sativa. 3,5-Diiodo-4-hydroxybenzoic acid only exhibited lower toxicity than ioxynil in the latter test.
- MeSH
- Actinobacteria účinky léků enzymologie metabolismus MeSH
- amidohydrolasy metabolismus MeSH
- amidy metabolismus MeSH
- aminohydrolasy metabolismus MeSH
- biodegradace účinky léků MeSH
- biotransformace účinky léků MeSH
- herbicidy metabolismus toxicita MeSH
- hydrolýza účinky léků MeSH
- kořeny rostlin účinky léků růst a vývoj MeSH
- nitrily metabolismus toxicita MeSH
- půdní mikrobiologie MeSH
- salát (hlávkový) účinky léků růst a vývoj MeSH
- testy akutní toxicity MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- městské obyvatelstvo MeSH
- poskytování zdravotní péče MeSH
- socialismus MeSH
- veřejné zdravotnictví MeSH
- Geografické názvy
- Československo MeSH
