Selective loss of lin genes from hexachlorocyclohexane-degrading Pseudomonas aeruginosa ITRC-5 under different growth conditions

Atul K. Singh, Pankaj Chaudhary, Ankit S. Macwan, Upendra N. Diwedi, Ashwani Kumar

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The chlorinated insecticide γ-hexachlorocyclohexane (γ-HCH) is sequentially metabolized by the products of linA, linB, linC, linD, linE, and linF genes to β-ketoadipate, which is subsequently mineralized. Two or more copies of these genes are present in the bacterium Pseudomonas aeruginosa ITRC-5 that was isolated earlier by selective enrichment on technical-HCH. At least one copy of linA, linB, linC, linD, and possibly linE is lost from ITRC-5 upon its growth on γ-HCH. All the lin genes, however, are lost when the bacterium was grown in Luria-Bertani (LB) medium. The loss of lin genes is accompanied with the loss/rearrangement of insertion sequence IS6100 genes. Concomitant to the loss of lin genes, the degradation of HCH-isomers by "γ-HCH grown cells" is slower, when compared with "technical-HCH grown cells", and is completely lost by "LB-grown cells". The selective loss of lin genes during different growth conditions has not been reported before and is expected to help in understanding the dynamism of degradative genes.

Original languageEnglish
Pages (from-to)895-901
Number of pages7
JournalApplied Microbiology and Biotechnology
Issue number4
StatePublished - 1 Sep 2007



  • Biodegradation
  • Hexachlorocyclohexane
  • IS6100
  • Pseudomonas aeruginosa
  • lin genes

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