Project description:Microbial reductive dechlorination of trichloroethene (TCE) in groundwater often results in the accumulation of dichloroethenes (DCEs). Dehalococcoides mccartyi (Dhc) are the only known bacteria capable of dechlorination beyond DCE to non-toxic ethene. In this study, two newly isolated Dhc strains (11a and 11a5) with dissimilar functional abilities are described. Strain 11a reductively dechlorinates TCE, 1,1-DCE, cis-DCE, trans-DCE, and vinyl chloride (VC) to ethene, while strain 11a5 dechlorinates TCE and all three DCE isomers only to VC. Each of these dechlorination reactions are coupled to growth by these strains. The VC dechlorination rate of strain 11a occurs at a rate of 258 nmol per min per mg of protein, about two times faster than previously reported stains. Strain 11a possesses the vcrA gene while strain 11a5 contains the tceA gene. Strains 11a and 11a5 share 100% 16S rRNA gene sequence identity with previously sequenced Dhc strains BAV1 and CBDB1, placing it within the Pinellas subgroup, and 85.4% and 89.5% of all genes present in the CBDB1 and BAV1 genomes were detected in strains 11a and 11a5, respectively, using a custom-designed microarray targeting four sequenced Dhc strains. Genes that were not detected in strains 11a and 11a5 are mostly within the high plasticity regions or integrated elements of the sequenced strains. This study reports the functional description and comparative genomics of two additional Dhc isolates and provides evidence that the observed functional incongruence between the activity and core genome phylogenies of Dhc strains is likely driven by the horizontal transfer of key reductive dehalogenase-encoding genes.

2013-03-01 | GSE27611 | GEO

Dehalococcoides mccartyi strain:CG3

Project description:Dehalococcoides mccartyi CG3 Raw sequence reads

| PRJNA280135 | ENA

Elucidating Salinity Stress and Engineered Solutions on Trichloroethene Bioremediation using a Consortium containing Dehalococcoides mccartyi

Project description:Groundwater salinization threatens contaminant bioremediation worldwide, yet how syntrophic microbial consortia—central to these processes—respond to salinity stress remains poorly understood. Using a defined trichloroethene-dechlorinating consortium comprising Dehalococcoides mccartyi strain 195 (Dhc195), Desulfovibrio vulgaris Hildenborough (DvH), and Pelosinus fermentans R7 (PfR7), we show that functional resilience under salinity is governed by syntrophic dependencies rather than the tolerance of keystone organisms alone. Under chronic salinity, dechlorination became incomplete above 16 g/L NaCl despite stable Dhc195 and DvH, reflecting impaired vitamin B12 supply by PfR7. Co-amendment with glycine betaine and vitamin B12 sustained function under chronic moderate salinity up to ~18 g/L NaCl, but not during acute salinity upsurge greater than 21 g/L NaCl. Axenic cultures showed uncoupling of Dhc195 growth and dechlorination at high salinity, while transcriptomic analyses indicated a shift toward survival-oriented, amino acid–based adaptation during acute stress. Consortium metabolomics further highlighted membrane remodeling and altered metabolic exchange under salinity stress. Together, these findings demonstrate that sustaining bioremediation in salinizing aquifers requires community-level strategies that explicitly account for syntrophic vulnerability rather than organism-centric tolerance.

2026-03-25 | GSE325731 | GEO

Morus alba Raw protein sequence reads

Project description:Morus alba L. Raw protein sequence reads and sequence

2024-02-08 | PXD049451 |

The PceA-Orthologous Reductive Dehalogenase of Dehalococcoides mccartyi CBDB1 Is Involved in 1,2,4-Trichlorobenzene Respiration

Project description:The reductive dehalogenation of halogenated benzenes by anaerobic bacteria is of great environmental and biotechnological importance; however, the role of specific reductive dehalogenases in the (sequential) dehalogenation of different isomers has not been studied in detail. Here, we cultivated the obligate organohalide-respiring Dehalococcoides mccartyi strain CBDB1 with either 1,2,3- or 1,2,4-trichlorobenzene (TCB) as electron acceptor and investigated differences in the expression of its 32 reductive dehalogenase (rdhA) genes using RNA-sequencing. The gene of the known chlorobenzene reductive dehalogenase, cbrA, and rdhA cbdbA80 were the two most highly expressed rdhA genes with 1,2,3-TCB. In the presence of 1,2,4-TCB, cbrA was also the most highly expressed rdhA, whereas rdhA cbdbA80 was transcribed at a slightly lower level. Instead, a third rdhA gene, cbdbA1588, encoding an orthologue of the tetrachloroethene reductive dehalogenase PceA, was the second most highly expressed rdhA. The screening of the transcripts encoded in intergenic regions predicted three abundant sRNAs and a so far unannotated small protein. Proteome analyses of cultures respiring 1,2,3-TCB, 1,2,4-TCB, or hexachlorobenzene (HCB) confirmed the specific synthesis of the RdhA CbdbA1588 protein during respiration with 1,2,4-TCB. It was also up-regulated by HCB, suggesting its involvement in sequential dechlorination to dichlorobenzenes. Dehalogenase activity assays with cell extracts from 1,2,4-TCB-grown cultures indicated a higher activity towards 1,2,4-TCB and a ten-fold higher activity towards 2,3-dichlorophenol compared to that in extracts from 1,2,3-TCB-grown cultures. These findings demonstrate the functionality of RdhA CbdbA1588 and further support a role in 1,2,4-TCB dechlorination by strain CBDB1.

2026-02-11 | PXD069682 | Pride