Global gene expression of Dehalococcoides within a robust dynamic TCE‐dechlorinating community under conditions of periodic substrate supply. Issue 5 (9th February 2013)

• Record Type: Journal Article
• Authors: West, Kimberlee A.; Lee, Patrick K.H.; Johnson, David R.; Zinder, Stephen H.; Alvarez‐Cohen, Lisa
• Is Part Of: Biotechnology and bioengineering. Volume 110:Issue 5(2013:May)
• Page Start: 1333
• Page End: 1341
• Publication Date: 2013-02-09
• Subjects: Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.24819
• Languages: English
• ISSNs: 0006-3592

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A microarray targeting four sequenced strains in the <italic>Dehalococcoides</italic> (Dhc) genus was used to analyze gene expression in a robust long‐term trichloroethene (TCE)‐degrading microbial community (designated ANAS) during feeding cycles that involve conditions of periodic substrate supply. The Dhc transcriptome was examined at three time‐points throughout a batch feeding cycle: <italic>T</italic><sub>1</sub> (27 h) when TCE, dichloroethene (DCE), and vinyl chloride (VC) were present; <italic>T</italic><sub>2</sub> (54 h) when only VC remained; and <italic>T</italic><sub>3</sub> (13 days) when Dhc had been starved of substrate for 9 days. Ninety percent of the Dhc open reading frames (ORFs) that were detected in the ANAS DNA were found to be expressed as RNA sometime during the time course, demonstrating extraordinary utilization of the streamlined genome. Ninety‐seven percent of these transcripts were differentially expressed during the time course indicating efficiency of transcription through regulation in Dhc. Most Dhc genes were significantly down‐regulated at <italic>T</italic><sub>3</sub>, responding to a lack of substrate as would be expected. The <italic>tceA</italic> and <italic>vcrA</italic> genes, which code for proteins with known chlorinated ethene reduction functions, were highly expressed at both <italic>T</italic><sub>1</sub> and <italic>T</italic><sub>2</sub>, whereas two other putative reductive dehalogenase genes (DET0173 and DET1545) were most highly expressed at <italic>T</italic><sub>2</sub>, likely in response to the presence of VC. Hydrogenases were most highly expressed at <italic>T</italic><sub>1</sub>, reflecting their important role in accumulating electrons used to initiate reductive dechlorination and other biosynthesis pathways. Cobalamin transport genes were preferentially expressed at <italic>T</italic><sub>2</sub>, reflecting an increase in corrinoid transport as chloroethenes were degraded and a decrease in activity of the transport system after dehalogenation was complete. This is the first application of a microarray targeting a known genus, including both core genomes and identified strain‐specific genes, to improve our understanding of transcriptional dynamics within an undefined microbial community. Biotechnol. Bioeng. 2013; 110: 1333–1341. © 2012 Wiley Periodicals, Inc.</p> </abstract>