Characterization of four TCE-dechlorinating microbial enrichments grown with different cobalamin stress and methanogenic conditions
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ABSTRACT:
ORGANISM(S): environmental samples
SUBMITTER: Yujie Men
PROVIDER: E-GEOD-33530 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The genomes of three newly isolated Dehalococcoides strains (11a, 11a5 and MB) were compared against known genomes in the Dehalococcoides genus via a microarray targeting four sequenced Dehalococcoides strains (195, CBDB1, BAV1, and VS). All three strains exhibit different dechlorination patterns, with strains 11a dechlorinating TCE to ethene, 11a5 dechlorinating TCE to VC and MB dechlorinating PCE only to isomers of DCE. Hybridization of their respective genomic DNA to the microarrays showed that the genomes of strains 11a and 11a5 show great similarity to each other and to strains CBDB1 and BAV1 of the Pinellas subgroup, while strain MB shows strong genome similarity to members of the Cornell subgroup. All genes within the respective subgroups that were not detected by microarray are within the respective high plasticity regions or integrated elements of the sequenced strains. A large number of reductive dehalogenase (RDase)-encoding genes are present within each genome, and the presence of the vcrA and tceA genes in strains 11a and 11a5 respectively, and the absence of any of the four functionally-characterized chlorinated ethene RDases (pceA, tceA, vcrA, bvcA) within strain MB appear to dictate chlorinated ethene usages regardless of the respective core genome phylogeny of the three strains. Considering the current data set together with previous comparative genomics results from application of the Dehalococcoides genus microarray to two other un-sequenced strains, the observed incongruence between the core genome phylogeny and chlorinated ethene usage of Dehalococcoides strains is likely driven by horizontal gene transfer of functional RDases. The other genomic features that are repeatedly observed in the microarray analyses of all five un-sequenced Dehalococcoides strains as well as the environmental implications on this work are presented in this study. The genomic DNA (gDNA) of each culture was analyzed in triplicate. gDNA from the two newly isolated Dehalococcoides strains 11a and 11a5 were analyzed.
2013-03-01 | E-GEOD-27611 | biostudies-arrayexpress
Project description:The chlorinated ethene-respiring bacteria of the genus Dehalococcoides are important for bioremediation. A microarray targeting genes from all available sequenced genomes of the Dehalococcoides genus was designed with 4305 probe sets to target 98.6% of all genes from strains 195, CBDB1, BAV1, and VS. The microarrays were validated with genomic DNA (gDNA) of strains 195 and BAV1 and satisfactory analytical reproducibility, quantitative response and gene detection accuracy were obtained. These microarrays were applied to query the genomes of two recently isolated Dehalococcoides strains, ANAS1 and ANAS2. Strains ANAS1 and ANAS2 can both couple the reduction of TCE, cDCE and 1,1-DCE but not PCE and tDCE with growth while only strain ANAS2 couples VC reduction to growth. Analysis of the respective gDNA using the microarrays showed that the genomes of both strains are similar to each other and to strain 195, except for genes that are within the previously defined integrated elements (IEs) or high plasticity regions (HPRs). Similar results to the combined isolates were obtained when gDNA of ANAS, the enrichment culture from which the two Dehalococcoides isolates originated, was applied to the microarrays. The genome similarities, together with the distinct chlorinated ethene usage of strains ANAS1, ANAS2 and 195 demonstrate that closely phylogenetically related strains can be physiologically different. This incongruence between physiology and core genome phylogeny appears to be driven by the presence of distinct reductive dehalogenase (RDase)-encoding genes with characterized chlorinated ethene functions (pceA, tceA in strain 195; tceA in strain ANAS1; vcrA in strain ANAS2). Genes encoding central metabolic functions of strain 195 were all detected in strains ANAS1 and ANAS2, while interestingly, the tryptophan operon of these strains is similar to that of strain VS. Overall, the microarrays are a valuable high-throughput tool for comparative genomics of un-sequenced Dehalococcoides-containing samples. The genomic DNA (gDNA) of each culture was analyzed in triplicate. gDNA from strain 195 and strain BAV1 was used as positive control, while gDNA from Anaeromyxobacter dehalogenans strain 2CP-C served as negative control in validating the microarray. gDNA from the two newly isolated strains ANAS1 and ANAS2 as well as the enrichment culture (ANAS) where the two strains originated was also analyzed.
2011-08-17 | E-GEOD-23707 | biostudies-arrayexpress
Project description:A microarray targeting four sequenced strains in the Dehalococcoides (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: T1 (27 h) when TCE, dichloroethene (DCE), and vinyl chloride (VC) were present; T2 (54 h) when only VC remained; and T3 (13 d) when Dhc had been starved of substrate for nine days. 90% of the Dhc 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. 97% 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 T3, responding to a lack of substrate as would be expected. The tceA and vcrA genes, which code for proteins with known chlorinated ethene reduction functions, were highly expressed at both T1 and T2, whereas two other putative reductive dehalogenase genes (DET0173 and DET1545) were most highly expressed at T2, likely in response to the presence of VC. Hydrogenases were most highly expressed at T1, reflecting their important role in accumulating electrons used to initiate reductive dechlorination and other biosynthesis pathways. Cobalamin transport genes were preferentially expressed at T2, 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, applied to improve our understanding of transcriptional dynamics within an undefined microbial community. Replicate samples were independently collected, and simultaneously but individually extracted, fragmented, labeled, and hybridized to arrays. Three DNA samples (one from each of the three replicate cycles) and nine RNA samples (one from each of the three time-points in each of the three replicate cycles) were prepared for microarray analysis.
2013-03-01 | E-GEOD-42635 | biostudies-arrayexpress
Project description:The syntrophic growth of strain 195 with Desulfovibrio vulgaris Hildenborough (DVH) and/or Methanobacterium congolense (MC) enhanced TCE dechlorination process by faster dechlorination rate and more robust growth. Transcriptomes of strain 195 grown in isolation, co- and tri-cultures were obtained by microarray experiments to find out the differential expressed genes corresponding to the syntrophic growth. Thus we can better understand the role of DVH and MC within this syntrophy. [Transcriptomic analysis]: Cells of pure strain 195 culture, co-culture and tri-culture were collected at the early exponential phase during TCE dechlorination process for RNA extraction, cDNA synthesis, fragmentation, labelling, and hybridization on microarray. We sought to obtain differential transcription of 195 genes in pure, co- and tri- cultures, in order to understand the role of DVH and MC in the syntrophy of strain 195.
2011-07-31 | E-GEOD-26815 | biostudies-arrayexpress
Project description:Tetrachloroethene (PCE) and trichloroethene (TCE) are prevalent groundwater contaminants that can be completely reductively dehalogenated by Dehalococcoides organisms. A Dehalococcoides-containing microbial consortium (ANAS) with the ability to degrade TCE to ethene, an innocuous end-product, was previously enriched from contaminated soil. A whole-genome photolithographic microarray was developed based on the genome of Dehalococcoides ethenogenes 195 (strain 195). This microarray contains probes designed to hybridize to >99% of the predicted protein-coding sequences in the strain 195 genome. DNA from ANAS was hybridized to the microarray to characterize the genomic content of the ANAS enrichment. The microarray revealed that the genes associated with central metabolism including an apparently incomplete carbon fixation pathway, cobalamin salvaging system, nitrogen fixation pathway, and five hydrogenase complexes are present in both strain 195 and ANAS. Although the gene encoding the TCE reductase tceA was detected, 13 of the 19 reductive dehalogenase genes present in strain 195 were not detected in ANAS. Additionally, 88% of the genes in predicted integrated genetic elements in strain 195 were not detected in ANAS, consistent with these elements being genetically mobile. Sections of the tryptophan operon and an operon encoding an ABC transporter in strain 195 were also not detected in ANAS. These insights into the diversity of Dehalococcoides genomes will improve our understanding of the physiology and evolution of these bacteria which is essential in developing effective strategies for bioremediation of PCE and TCE in the environment. Keywords: comparative genomic hybridization Genomic DNA from each culture was divided into replicate samples which were independently fragmented, labeled, and hybridized to arrays. Two microarrays were processed for the positive control (strain 195), two for the negative control (D. restrictus), and five for the ANAS enrichment culture(two analyses from one biological sample followed one year later by three analyses of a second biological sample).
2010-06-20 | E-GEOD-9612 | biostudies-arrayexpress
Project description:Four stable and robust TCE-dechlorinating microbial communities were enriched from TCE-contaminated groundwater under four different conditions exploring two parameters, high and low methanogenic activity (Meth and NoMeth), with and without vitamin B12 supplement (MethB12 and NoMethB12, Meth and NoMeth, respectively). Identical amounts of lactate (2.7 mmol) and TCE (20 μl) were supplied as electron donor and electron acceptor. All four cultures were capable of reductively dechlorinating TCE to VC and ethene. Genomic DNA of the four enrichments was applied on a quad-Dhc-genome microarray in order to characterize the gene content of Dehalococcoides species present in the four enrichments
2013-06-30 | GSE33530 | GEO
Project description:Polybrominated diphenyl ethers (PBDEs) are persistent, highly toxic, and widely distributed environmental pollutants. The microbial populations and functional reductive dehalogenases (RDases) responsible for PBDEs debromination in anoxic systems remain poorly understood, which confounds bioremediation of PBDE-contaminated sites. Here we report a PBDE-debrominating enrichment culture dominated by a previously undescribed Dehalococcoides mccartyi population. A D. mccartyi strain, designated TZ50, whose genome contains 25 putative RDase encoding genes was isolated from the debrominating enrichment culture. Strain TZ50 dehalogenated a mixture of penta- and tetra-BDE congeners (total BDEs 1.48 uM) to diphenyl ether within two weeks (0.58 uM Br- /d) via ortho- and meta- bromine elimination; strain TZ50 also dechlorinated tetrachloroethene (PCE) to vinyl chloride and ethene (260.2 M Cl- /d). Native-PAGE, proteomic profiling, and in vitro enzymatic activity assays implicated the involvement of three RDases in PBDEs and PCE dehalogenation. Two RDases, TZ50_0172 (PteATZ50) and TZ50_1083 (TceATZ50), were responsible for debromination of penta- and tetra-BDEs to di-BDE. TZ50_0172 and TZ50_1083 were also implicated in dechlorination of PCE to TCE and of TCE to vinyl chloride/ethene, respectively. The other expressed dehalogenase, TZ50_0090, was associated with debromination of di-BDE to diphenyl ether, but its role in PCE dechlorination was unclear. Comparatively few RDases are known to be involved in PBDE debromination and the identification of PteATZ50, TceATZ50, and TZ50_0090 provides additional information for evaluating debromination potential at contaminated sites. Moreover, the bifunctionality of the PteATZ50 and TceATZ50 in both PBDEs and PCE dehalogenation makes strain TZ50 a suitable candidate for remediation of co-contaminated sites.
2021-06-16 | PXD024983 | Pride
Project description:Dehalococcoides mccartyi are functionally important bacteria that catalyze the reductive dechlorination of chlorinated ethenes. However, these anaerobic bacteria are fastidious to isolate, making downstream genomic characterization challenging. In order to facilitate genomic analysis, a fluorescence-activated cell sorting (FACS) method was developed in this study to separate D. mccartyi cells from a microbial community, and the DNA of the isolated cells was processed by whole genome amplification (WGA) and hybridized onto a D. mccartyi microarray for comparative genomics against four sequenced strains. First, FACS was successfully applied to a D. mccartyi isolate as positive control, and then microarray results verified that WGA from 106 cells or M-bM-^HM-<1 ng of genomic DNA yielded high-quality coverage detecting nearly all genes across the genome. As expected, some inter- and intrasample variability in WGA was observed, but these biases were minimized by performing multiple parallel amplifications. Subsequent application of the FACS and WGA protocols to two enrichment cultures containing M-bM-^HM-<10% and M-bM-^HM-<1% D. mccartyi cells successfully enabled genomic analysis. As proof of concept, this study demonstrates that coupling FACS with WGA and microarrays is a promising tool to expedite genomic characterization of target strains in environmental communities where the relative concentrations are low. The genomic DNA (gDNA) of each culture or sorted and amplifed DNA was analyzed in triplicate.
2015-01-31 | E-GEOD-54040 | biostudies-arrayexpress
Project description:Tetrachloroethene (PCE) and trichloroethene (TCE) are prevalent groundwater contaminants that can be completely reductively dehalogenated by Dehalococcoides organisms. A Dehalococcoides-containing microbial consortium (ANAS) with the ability to degrade TCE to ethene, an innocuous end-product, was previously enriched from contaminated soil. A whole-genome photolithographic microarray was developed based on the genome of Dehalococcoides ethenogenes 195 (strain 195). This microarray contains probes designed to hybridize to >99% of the predicted protein-coding sequences in the strain 195 genome. DNA from ANAS was hybridized to the microarray to characterize the genomic content of the ANAS enrichment. The microarray revealed that the genes associated with central metabolism including an apparently incomplete carbon fixation pathway, cobalamin salvaging system, nitrogen fixation pathway, and five hydrogenase complexes are present in both strain 195 and ANAS. Although the gene encoding the TCE reductase tceA was detected, 13 of the 19 reductive dehalogenase genes present in strain 195 were not detected in ANAS. Additionally, 88% of the genes in predicted integrated genetic elements in strain 195 were not detected in ANAS, consistent with these elements being genetically mobile. Sections of the tryptophan operon and an operon encoding an ABC transporter in strain 195 were also not detected in ANAS. These insights into the diversity of Dehalococcoides genomes will improve our understanding of the physiology and evolution of these bacteria which is essential in developing effective strategies for bioremediation of PCE and TCE in the environment. Keywords: comparative genomic hybridization
2008-09-01 | GSE9612 | GEO
Project description:Bacteria of the genus Dehalococcoides play an important role in the reductive dechlorination of chlorinated ethenes. A systems level approach was taken in this study to examine the global transcriptomic and proteomic responses of exponentially growing D. ethenogenes strain 195 to fixed nitrogen limitation (FNL). As expected, the nitrogen-fixing (nif) genes were differentially up-regulated in the transcriptome and proteome of strain 195 during FNL. Aside from the nif operon, a putative methylglyoxal synthase-encoding gene (DET1576), which is predicted to catalyze the formation of the toxic electrophile methylglyoxal and implicated in the uncoupling of anabolism from catabolism in bacteria, was strongly up-regulated in the transcriptome and could potentially play a role in the observed growth inhibition during FNL. Carbon catabolism genes were generally down regulated in response to FNL and a number of transporters were differentially regulated in response to nitrogen limitation, with some playing apparent roles in nitrogen acquisition while others were associated with general stress responses. A number of genes related to the biological functions of nucleotide synthesis, replication, transcription, translation, and post-translational modifications were also differentially expressed. One gene coding for a putative reductive dehalogenase (DET1545) and a number coding for oxidoreductases, which have implications in energy generation and redox reactions, were also differentially regulated. Interestingly, most of the genes within the multiple integrated elements were not differentially expressed. Overall, this study elucidates the molecular responses of strain 195 to FNL and identifies differentially expressed genes that are potential biomarkers to evaluate cellular nitrogen status in the environment. Dehalococcoides ethenogenes strain 195 was grown with or without ammonium in batch cultures with trichloroethene as the electron acceptor, acetate as the carbon source, and hydrogen as the electron donor. Microarrays were used to compare the transcriptome during fixed nitrogen limitation and triplicate biological samples were prepared for each condition. Differentially expressed genes between the two growth conditions were identified using a two-tailed Student's t-test, a false discovery rate of less than 1%, an absolute hybridization signal intensity of 300 or greater in one of the two conditions, and an expression ratio of two-fold or greater.
2012-04-25 | E-GEOD-28855 | biostudies-arrayexpress