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Published on: October 15, 2015
Multiple reductive-dehalogenase-homologous genes are simultaneously transcribed during dechlorination by
Alison S Waller1, Rosa Krajmalnik-Brown, Frank E Löffler
1Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada.
Applied and Environmental Microbiology
|December 8, 2005
Summary
Multiple reductive dehalogenase (RDH) genes in Dehalococcoides bacteria are transcribed when exposed to chlorinated compounds. This indicates that several RDH enzymes work together to degrade chloroethenes.
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Dehalococcoides bacteria are key players in the reductive dechlorination of chlorinated pollutants.
- Reductive dehalogenase (RDH) genes are crucial for this process, but their differential expression is not fully understood.
Purpose of the Study:
- To investigate the transcriptional response of multiple RDH genes in a Dehalococcoides-containing mixed culture (KB1) under various chlorinated electron acceptor conditions.
- To determine if multiple RDH genes are co-regulated and contribute to chloroethene degradation.
Main Methods:
- Degenerate primers were used to amplify 14 RDH genes from KB1.
- KB1 was cultured with different chlorinated electron acceptors (trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,2-dichlorethane) or without.
- RDH gene transcription was analyzed via reverse transcription and PCR amplification of RNA.
Main Results:
- RDH gene transcription was dependent on the presence of a chlorinated electron acceptor.
- Multiple RDH genes were transcribed simultaneously under all tested conditions.
- Two RDH genes, similar to known vinyl chloride reductases (vcrA, bvcA), were consistently transcribed.
Conclusions:
- The transcription of RDH genes is induced by specific chlorinated electron acceptors.
- Multiple reductive dehalogenases are likely involved in the degradation of chloroethenes by Dehalococcoides.
- This suggests a complex enzymatic system for complete chloroethene remediation.
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