Publications

• Purification and characterization of a novel carbaryl hydrolase from Aspergillus niger PY168.

  Zhang Q., Liu Y., Liu Y.H.

  A fungus capable of using carbaryl as the sole source of carbon and energy was isolated from a soil enrichment, and characterized as Aspergillus niger and designated strain PY168. A novel carbaryl hydrolase from cell extract was purified 262-fold to apparent homogeneity with 13.6% overall recovery ... >> More

  A fungus capable of using carbaryl as the sole source of carbon and energy was isolated from a soil enrichment, and characterized as Aspergillus niger and designated strain PY168. A novel carbaryl hydrolase from cell extract was purified 262-fold to apparent homogeneity with 13.6% overall recovery. It had a monomeric structure with a molecular mass of 50,000 Da and a pI of 4.6, and the enzyme activity was optimal at 45 degrees C and pH 7.5, The activities were strongly inhibited by Hg(2+), Ag+, rho-chloromercuribenzoate, iodoacetic acid, diisofluorophosphate and phenylmethylsulfonyl fluoride but not EDTA and phenanthroline. The purified enzyme hydrolyzed various N-methylcarbamate insecticides. Carbaryl is the preferred substrate. << Less

  FEMS Microbiol Lett 228:39-44(2003) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Hydrolase CehA and Monooxygenase CfdC Are Responsible for Carbofuran Degradation in Sphingomonas sp. Strain CDS-1.

  Yan X., Jin W., Wu G., Jiang W., Yang Z., Ji J., Qiu J., He J., Jiang J., Hong Q.

  Carbofuran, a broad-spectrum systemic insecticide, has been extensively used for approximately 50 years. Diverse carbofuran-degrading bacteria have been described, among which sphingomonads have exhibited an extraordinary ability to catabolize carbofuran; other bacteria can only convert carbofuran ... >> More

  Carbofuran, a broad-spectrum systemic insecticide, has been extensively used for approximately 50 years. Diverse carbofuran-degrading bacteria have been described, among which sphingomonads have exhibited an extraordinary ability to catabolize carbofuran; other bacteria can only convert carbofuran to carbofuran phenol, while all carbofuran-degrading sphingomonads can degrade both carbofuran and carbofuran phenol. However, the genetic basis of carbofuran catabolism in sphingomonads has not been well elucidated. In this work, we sequenced the draft genome of <i>Sphingomonas</i> sp. strain CDS-1 that can transform both carbofuran and carbofuran phenol but fails to grow on them. On the basis of the hypothesis that the genes involved in carbofuran catabolism are highly conserved among carbofuran-degrading sphingomonads, two such genes, <i>cehA</i>_CDS-1 and <i>cfdC</i>_CDS-1, were predicted from the 84 open reading frames (ORFs) that share ≥95% nucleic acid similarities between strain CDS-1 and another sphingomonad <i>Novosphingobium</i> sp. strain KN65.2 that is able to mineralize the benzene ring of carbofuran. The results of the gene knockout, genetic complementation, heterologous expression, and enzymatic experiments reveal that <i>cehA</i>_CDS-1 and <i>cfdC</i>_CDS-1 are responsible for the conversion of carbofuran and carbofuran phenol, respectively, in strain CDS-1. CehA_CDS-1 hydrolyzes carbofuran to carbofuran phenol. CfdC_CDS-1, a reduced flavin mononucleotide (FMNH₂)- or reduced flavin adenine dinucleotide (FADH₂)-dependent monooxygenase, hydroxylates carbofuran phenol at the benzene ring in the presence of NADH, FMN/FAD, and the reductase CfdX. It is worth noting that we found that carbaryl hydrolase CehA_AC100, which was previously demonstrated to have no activity toward carbofuran, can actually convert carbofuran to carbofuran phenol, albeit with very low activity.<b>IMPORTANCE</b> Due to the extensive use of carbofuran over the past 50 years, bacteria have evolved catabolic pathways to mineralize this insecticide, which plays an important role in eliminating carbofuran residue in the environment. This study revealed the genetic determinants of carbofuran degradation in <i>Sphingomonas</i> sp. strain CDS-1. We speculate that the close homologues <i>cehA</i> and <i>cfdC</i> are highly conserved among other carbofuran-degrading sphingomonads and play the same roles as those described here. These findings deepen our understanding of the microbial degradation mechanism of carbofuran and lay a foundation for the better use of microbes to remediate carbofuran contamination. << Less

  Appl Environ Microbiol 84:e00805-18(2018) [PubMed] [EuropePMC]

• Expanded insecticide catabolic activity gained by a single nucleotide substitution in a bacterial carbamate hydrolase gene.

  Ozturk B., Ghequire M., Nguyen T.P., De Mot R., Wattiez R., Springael D.

  Carbofuran-mineralizing strain Novosphingobium sp. KN65.2 produces the CfdJ enzyme that converts the N-methylcarbamate insecticide to carbofuran phenol. Purified CfdJ shows a remarkably low K_M towards carbofuran. Together with the carbaryl hydrolase CehA of Rhizobium sp. strain AC100, C ... >> More

  Carbofuran-mineralizing strain Novosphingobium sp. KN65.2 produces the CfdJ enzyme that converts the N-methylcarbamate insecticide to carbofuran phenol. Purified CfdJ shows a remarkably low K_M towards carbofuran. Together with the carbaryl hydrolase CehA of Rhizobium sp. strain AC100, CfdJ represents a new protein family with several uncharacterized bacterial members outside the proteobacteria. Although both enzymes differ by only four amino acids, CehA does not recognize carbofuran as a substrate whereas CfdJ also hydrolyzes carbaryl. None of the CfdJ amino acids that differ from CehA were shown to be silent regarding carbofuran hydrolytic activity but one particular amino acid substitution, i.e., L152 to F152, proved crucial. CfdJ is more efficient in degrading methylcarbamate pesticides with an aromatic side chain whereas CehA is more efficient in degrading the oxime carbamate nematicide oxamyl. The presence of common flanking sequences suggest that the cfdJ gene is located on a remnant of the mobile genetic element Tnceh carrying cehA. Our results suggest that these enzymes can be acquired through horizontal gene transfer and can evolve to degrade new carbamate substrates by limited amino acid substitutions. We demonstrate that a carbaryl hydrolase can gain the additional capacity to degrade carbofuran by a single nucleotide transversion. << Less

  Environ Microbiol 18:4878-4887(2016) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Purification and characterization of the N-methylcarbamate hydrolase from Pseudomonas strain CRL-OK.

  Mulbry W.W., Eaton R.W.

  A unique cytosolic enzyme that hydrolyzes the carbamate linkage of the insecticide carbaryl (1-naphthyl N-methylcarbamate) was purified from extracts of Pseudomonas sp. strain CRL-OK. Substrates of the hydrolase include the N-methylcarbamate pesticides carbofuran and aldicarb but not the phenylcar ... >> More

  A unique cytosolic enzyme that hydrolyzes the carbamate linkage of the insecticide carbaryl (1-naphthyl N-methylcarbamate) was purified from extracts of Pseudomonas sp. strain CRL-OK. Substrates of the hydrolase include the N-methylcarbamate pesticides carbofuran and aldicarb but not the phenylcarbamate isopropyl m-chlorocarbanilate, the thiocarbamate S-ethyl N,N-dipropylthiocarbamate, or the dimethylcarbamate o-nitrophenyldimethylcarbamate. << Less

  Appl Environ Microbiol 57:3679-3682(1991) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.