Assays of PCB congeners and organochlorine insecticides with the transgenicArabidopsisand tobacco plants carrying recombinant guinea pig AhR and GUS reporter genes

Abstract

Certain congeners of polychlorinated biphenyls (PCBs) and organochlorine insecticides are ligands of aryl hydrocarbon receptors (AhRs) in animals. A recombinant guinea pig (g) AhR, XgDV, was constructed by fusing the ligand-binding domain of gAhR, the DNA-binding domain of LexA, and the transactivating domain of VP16. Then, the expression unit of β-glucuronidase (GUS) reporter gene regulated by XgDV was introduced into Arabidopsis and tobacco plants. When the transgenic Arabidopsis XgDV plants were cultured on Murashige-Skoog (MS) medium containing PCB congeners, the GUS activity in the plants increased toxic equivalent (TEQ)-dependently. The GUS activity in the transgenic Arabidopsis XgDV plants cultured on MS medium containing the organochlorine insecticide dieldrin was also induced. On the other hand, in the case of DDT, the GUS activity induced by 3-methylcholanthere in the plants decreased. The transgenic Arabidopsis XgDV plants detected 1000 ng g(-1) PCB126 in 1 g of soils. Thus the XgDV plants seemed to be useful for convenient assays of PCB congeners and organochlorine insecticides, without any extraction and purification steps.

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

“…[11, 12] In transgenic Arabidopsis plants carrying genes encoding a recombinant guinea pig AhR and the GUS reporter, p , p -DDT, p , p’ -dichloro-diphenyl-dichloroethane ( p , p -DDE), and p , p -dichloro-diphenyl-dichloroethylene ( p , p -DDD) decreased the GUS activity induced by MC. [13] Antagonism between the agonist MC and dieldrin or p , p’ -DDT was also observed in an in vitro assay using an Ah immunoassay. [13] The present assay responded to both agonists and antagonists among PCB congeners.…”

“…[13] Antagonism between the agonist MC and dieldrin or p , p’ -DDT was also observed in an in vitro assay using an Ah immunoassay. [13] The present assay responded to both agonists and antagonists among PCB congeners. Therefore, the GUS activity in the assay may reflect the relative toxicity level of a mixture of PCB congeners.…”

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

“…One transgenic plant line expressing such a fusion protein showed the highest β‐glucuronidase‐inducible activity, detecting low 3‐MC concentrations ranging from 1.6 n m to 1 μ m , a threefold improvement compared to the original AhR/ARNT/XRE system. 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, ).…”

Simple monitoring of endocrine-disrupting chemicals using transgenic Arabidopsis plants expressing medaka estrogen receptor

“…The sensitivity of these plants was further improved by introduction of each three major latex-like proteins cloned from zucchini plants (Stoykova and Inui, 2021). Transgenic Arabidopsis plants with a guinea pig AhR could detect 1 ng/mL dieldrin and 100 ng/g 3,3',4,4',5-pentachlorobiphenyl in soil (Gion et al, 2012). The concept of transgenic plant-based monitoring systems is improving its potential and allows the evaluation of soil and/or water pollution in a rapid, simplified, and cost-efficient way by eliminating the need for timeand labor-consuming procedures such as extraction, purification, and concentration of pollutants from environmental samples with complex matrices for instrumental analyses.…”