Assays of dioxins and dioxin-like compounds in actually contaminated soils using transgenic tobacco plants carrying a recombinant mouse aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system

Abstract

The transgenic tobacco plant XD4V-26 carrying the recombinant mouse aryl hydrocarbon receptor XD4V-mediated β-glucuronidase (GUS) reporter gene expression system was used for assay of dioxins and dioxin-like compounds consisting of polychlorodibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls (Co-PCBs) in actually contaminated soils. The transgenic tobacco plant XD4V-26 showed a significant dose-dependent induced GUS activity when cultured on MS medium containing PCB126 [toxic equivalency factor (TEF) = 0.1]. In contrast, PCB169 and PCB180, which have 0.03 of TEF and unassigned TEF values, respectively, did not significantly induce GUS activity under the same conditions as with PCB126. When the tobacco plants were cultivated for up to 5 weeks on actually contaminated soils with dioxins and dioxin-like compounds collected from the periphery of an incinerator used for disposal of life and industrial wastes, GUS activity in the leaves was dose-dependently increased. The plants clearly detected 360 pg-TEQ g−1 of dioxins and dioxin-like compounds in this assay. There was a positive correlation between GUS activity and TEQ value of dioxins and dioxin-like compounds in the plants. This assay does not require any extraction and purification processes for the actually contaminated soil samples.

Aryl hydrocarbon receptor‐based bioassays for dioxin detection: Thinking outside the box

“…Additional modifications, including the use of hAhR and guinea pig AhR proteins, and the introduction of this system in the Arabidopsis thaliana plant, were later implemented (Gion et al, ; Shimazu et al, ). More recently, bioassays based on transgenic plants were used to evaluate the presence of dioxins and dioxin‐like compounds in contaminated soil, a strategy coined “phytomonitoring” (Inui et al, ; Shimazu, Inui, & Ohkawa, ; Shimazu, Ohta, Ohkawa, & Ashida, ).…”

An overview of detection techniques for monitoring dioxin-like compounds: latest technique trends and their applications

“…31,47,91 In addition, cell culture bioassays determine the level of dioxin-induced gene expression by employing a native response including CYP1A induction and by increasing an articial construct expression consisting luciferase or other reporter genes under the control of particular regulatory parameters, which are able to respond to dioxin mixtures or compounds. 61,97,98 The analyzed results obtained from PCB, PCDF, and PCDD congeners, conrm that the amount of the relative potencies (REP) to induce the chemical-activated luciferase gene expression activity (CALUX) in mouse and rat were signicantly correlated with the reported amount of TEF. [92][93][94] Since that time, various studies added more improvements in sensitivity and speed by using uorescent plate readers and multi-well plates.…”