Effects of Arsenic on Trichloroethene–Dechlorination Activities of Dehalococcoides mccartyi 195

Abstract

Arsenic and trichloroethene (TCE) are among the most prevalent groundwater contaminants in the United States. Cocontamination of these two compounds has been detected at 63% of current TCE-contaminated National Priorities List sites. When in situ TCE reductive dechlorination is stimulated by the addition of fermentable substrates to generate a reducing environment, the presence of arsenic can be problematic because of the potential for increased mobilization and toxicity caused by the reduction of arsenate [As(V)] to arsenite [As(III)]. This study assesses the effects of arsenic exposure on the TCE-dechlorinating activities of Dehalococcoides mccartyi strain 195. Our results indicate that 9.1 μM As(III) caused a 50% decrease in D. mccartyi cell growth. While As(V) concentrations up to 200 μM did not initially impact TCE dechlorination, inhibition was observed in cultures amended with 200 μM As(V) and 100 μM As(V) in 12 and 17 days, respectively, corresponding with the accumulation of As(III). Transcriptomic and metabolomic analyses were performed to evaluate cellular responses to both As(V) and As(III) stress. Amendment of amino acids enhanced arsenic tolerance of D. mccartyi. Results from this study improve our understanding of potential inhibitions of D. mccartyi metabolism caused by arsenic and can inform the design of bioremediation strategies at co-contaminated sites.

Characterizing Natural Organic Matter Transformations by Microbial Communities in Terrestrial Subsurface Ecosystems: A Critical Review of Analytical Techniques and Challenges

“…Transcriptomics can be used to examine the pattern of gene expression during monitored physiological activities and in response to environmental conditions ( Konopka and Wilkins, 2012 ; Gushgari-Doyle and Alvarez-Cohen, 2020 ). There are very few studies, in any environment, that have coupled transcriptomics with complex organic matter characterization to identify correlations among the datasets.…”

“…Metagenomics is ideal for capturing the genomic capabilities of microbial communities ( Anantharaman et al, 2016 ; Long et al, 2016 ), particularly if used in conjunction with cultivation-approaches that test expected genotype–phenotype-functional relationships ( Wu et al, 2020 ). Transcriptomics, although not as commonly used in the subsurface, can yield critical insights into active gene expression in response to environmental conditions ( Konopka and Wilkins, 2012 ; Gushgari-Doyle and Alvarez-Cohen, 2020 ). Proteomics and metabolomics are considered more direct indicators of microbial activity because they are the actively expressed proteins and metabolites, respectively.…”

Metabolic reprogramming in crustaceans: A vital immune and environmental response strategy

“…128 This potential metabolic inhibition by heavy metals can serve as references for designing bioremediation strategies in polluted areas. 223…”

Iron Sulfide Enhanced the Dechlorination of Trichloroethene by Dehalococcoides mccartyi Strain 195

“…Using Phusion DNA polymerase, PCR amplicons after 15 PCR cycles were sequenced with the Illumina HiSeq × TEN (2 × 150 bp read length). The data generated from the Illumina platform were used for bioinformatics analyses as previously described (Barry et al, 2005;Gushgari-Doyle and Alvarez-Cohen, 2020). Statistical significance of differentially expressed transcripts was defined as fold-change ≥ 2 and p-value < 0.05.…”