Metabolism of carbaryl via 1,2-dihydroxynaphthalene by soil isolates Pseudomonas sp. strains C4, C5, and C6

Appl Environ Microbiol. 2005 Oct;71(10):5951-6. doi: 10.1128/AEM.71.10.5951-5956.2005.


Pseudomonas sp. strains C4, C5, and C6 utilize carbaryl as the sole source of carbon and energy. Identification of 1-naphthol, salicylate, and gentisate in the spent media; whole-cell O2 uptake on 1-naphthol, 1,2-dihydroxynaphthalene, salicylaldehyde, salicylate, and gentisate; and detection of key enzymes, viz, carbaryl hydrolase, 1-naphthol hydroxylase, 1,2-dihydroxynaphthalene dioxygenase, and gentisate dioxygenase, in the cell extract suggest that carbaryl is metabolized via 1-naphthol, 1,2-dihydroxynaphthalene, and gentisate. Here, we demonstrate 1-naphthol hydroxylase and 1,2-dihydroxynaphthalene dioxygenase activities in the cell extracts of carbaryl-grown cells. 1-Naphthol hydroxylase is present in the membrane-free cytosolic fraction, requires NAD(P)H and flavin adenine dinucleotide, and has optimum activity in the pH range 7.5 to 8.0. Carbaryl-degrading enzymes are inducible, and maximum induction was observed with carbaryl. Based on these results, the proposed metabolic pathway is carbaryl --> 1-naphthol --> 1,2-dihydroxynaphthalene --> salicylaldehyde --> salicylate --> gentisate --> maleylpyruvate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbaryl / metabolism*
  • Culture Media
  • Dioxygenases / metabolism
  • Gene Expression Regulation, Bacterial
  • Naphthols / metabolism*
  • Oxygenases / metabolism
  • Pseudomonas / classification
  • Pseudomonas / enzymology*
  • Pseudomonas / isolation & purification
  • Soil Microbiology*


  • Culture Media
  • Naphthols
  • 1,2-dihydroxynaphthalene
  • Oxygenases
  • Dioxygenases
  • Carbaryl