A whole-cell bioreporter assay for quantitative genotoxicity evaluation of environmental samples

Abstract

Whole-cell bioreporters have emerged as promising tools for genotoxicity evaluation, due to their rapidity, cost-effectiveness, sensitivity and selectivity. In this study, a method for detecting genotoxicity in environmental samples was developed using the bioluminescent whole-cell bioreporter Escherichia coli recA::luxCDABE. To further test its performance in a real world scenario, the E. coli bioreporter was applied in two cases: i) soil samples collected from chromium(VI) contaminated sites; ii) crude oil contaminated seawater collected after the Jiaozhou Bay oil spill which occurred in 2013. The chromium(VI) contaminated soils were pretreated by water extraction, and directly exposed to the bioreporter in two phases: aqueous soil extraction (water phase) and soil supernatant (solid phase). The results indicated that both extractable and soil particle fixed chromium(VI) were bioavailable to the bioreporter, and the solid-phase contact bioreporter assay provided a more precise evaluation of soil genotoxicity. For crude oil contaminated seawater, the response of the bioreporter clearly illustrated the spatial and time change in genotoxicity surrounding the spill site, suggesting that the crude oil degradation process decreased the genotoxic risk to ecosystem. In addition, the performance of the bioreporter was simulated by a modified cross-regulation gene expression model, which quantitatively described the DNA damage response of the E. coli bioreporter. Accordingly, the bioluminescent response of the bioreporter was calculated as the mitomycin C equivalent, enabling quantitative comparison of genotoxicities between different environmental samples. This bioreporter assay provides a rapid and sensitive screening tool for direct genotoxicity assessment of environmental samples.

iTRAQ-Based Comparative Proteomic Analysis of Acinetobacter baylyi ADP1 Under DNA Damage in Relation to Different Carbon Sources

“…After 3-h exposure, cells were harvested by centrifugation at 6000 × g for 15 min at 4 • C for further analysis. Although some previous studies have reported the application of 3 µM mitomycin C to induce A. baylyi cells, the concentration of mitomycin C used in the present study was set as 1 µM, because our previous work has reported a linear detection range of 0.1 nM to 1 µM for ADPWH_recA postexposure to mitomycin C (Jiang et al, 2017). Accordingly, mitomycin C concentration at 1 µM could induce the highest bioluminescent response of bioreporter cells, whereas higher concentration could significantly inhibit cell growth and might affect proteomic profiles (Song et al, 2009).…”

“…Acinetobacter baylyi ADP1 is a well-established soil microorganism for gene manipulation owing to its natural transformation ability (Barbe et al, 2004) and tolerance to environmental stress (Al-Anizi et al, 2014). Many studies have constructed various bioreporters with A. baylyi ADP1 as hosts for genotoxicity assessment of environmental samples (Song et al, 2009(Song et al, , 2014Zhang et al, 2013;Jiang et al, 2014Jiang et al, , 2017Jia et al, 2016). A previous study has documented that the DNA damage response in A. baylyi ADP1 was dependent on carbon source at both transcriptional and translational levels (Jiang et al, 2015).…”

Development of a Sensitive Escherichia coli Bioreporter Without Antibiotic Markers for Detecting Bioavailable Copper in Water Environments

“…Whole-cell bioreporters have gained worldwide attention because they are sensitive, selective, portable, reasonably priced, and easy to handle. In addition, they have a relatively long life and a short response time (Fan et al, 2017;Jiang et al, 2017). Typically, a whole-cell bioreporter is consisted of a promoteroperator, which acts as the sensing element for heavy metal ions, with one or more reporter genes that encode easily detectable proteins (Jiang et al, 2017).…”

“…In addition, they have a relatively long life and a short response time (Fan et al, 2017;Jiang et al, 2017). Typically, a whole-cell bioreporter is consisted of a promoteroperator, which acts as the sensing element for heavy metal ions, with one or more reporter genes that encode easily detectable proteins (Jiang et al, 2017). However, to survive in high levels of heavy metal and reduce its toxic effect, bacteria have evolved a variety of heavy metal resistance mechanisms involved in the extrusion of metal ions from the cell (Leedjarv et al, 2008).…”

Bacterial Bioreporter‐Based Mercury and Phenanthrene Assessment in Yangtze River Delta Soils of China

“…Although properly tested in amended water or standard soil materials, the actual performance of those bioreporters in real soil samples remains to be established (Peng et al, 2013; Nwaichi et al, 2014; Sun et al, 2014; Yoon et al, 2016a; Jiang et al, 2017; Mahbub et al, 2017; Zhang et al, 2017). In this study, the rapid determination and large‐scale screening of bioavailable Hg (b‐Hg) and PHE (b‐PHE) were performed on samples collected from the Yangtze River Delta (YRD).…”