In vitro bioassay for reactive toxicity towards proteins implemented for water quality monitoring

Tang, Janet, Glenn, Eva, Thoen, Hanne and Escher, Beate (2012). In vitro bioassay for reactive toxicity towards proteins implemented for water quality monitoring. In: F. D. L. Leusch, E. Prochazka and B. I. Escher, Proceedings of the 2nd SETAC Australasia Conference. 2nd SETAC Australasia Conference, Brisbane, Australia, (162-162). 4-6 July 2012.

Author Tang, Janet
Glenn, Eva
Thoen, Hanne
Escher, Beate
Title of paper In vitro bioassay for reactive toxicity towards proteins implemented for water quality monitoring
Conference name 2nd SETAC Australasia Conference
Conference location Brisbane, Australia
Conference dates 4-6 July 2012
Proceedings title Proceedings of the 2nd SETAC Australasia Conference
Place of Publication Brisbane, Australia
Publisher SETAC Australasia
Publication Year 2012
Sub-type Published abstract
Editor F. D. L. Leusch
E. Prochazka
B. I. Escher
Start page 162
End page 162
Total pages 1
Language eng
Formatted Abstract/Summary
An in vitro test system was developed to evaluate the hazards and mode of action classification of reactive chemicals for environmental risk assessment. Current  bioanalytical tools on reactive toxicity focus mainly on DNA damage however protein damage is also an important endpoint for toxicity caused by reactive chemicals. Reactive toxicity results from covalent binding of electrophilic organic pollutants to proteins have the potential to initiate severe adverse biological effects such as skin sensitization, respiratory allergy, organ toxicity, genotoxicity and mutagenicity. A number of in chemico assays targeting soft electrophiles have been used to evaluate the toxic potential of a substance, so far there is only one in vitro bioassay using E. coli to measure the reactivity of soft electrophiles. We successfully adopted the E. coli assay from a closed glass tube system to a 96‐well microtitre plate system. This bioassay is based on genetically modified E. coli strains to quantify the specific reactivity towards glutathione. Glutathione (GSH) is a small tripeptide whose cysteine moiety serves as  a model for nucleophilic sites on proteins, and also is an important indicator of detoxification processes as well as the redox status of the cells. The significance of GSH for detoxification was assessed by comparing the growth inhibition of the GSH‐deficient strain to its fully functional parent strain. Seven reference compounds serving as positive and negative controls were investigated. The E. coli strain that lacks GSH was four times more sensitive towards the positive control Sea‐Nine, while negative controls benzo[a]pyrene, 2‐aminoanthracene, phenol, t‐butylhydroquinone, methyl methane sulfonate and 4‐nitroquinoline oxide showed equal effect concentrations in both strains. Water samples collected across an indirect potable reuse scheme representing the complete water cycle from sewage to drinking water in South East Queensland were used to evaluate the applicability of the E. coli assay for reactive toxicity. While the effect concentrations showed similar trends as in other biological endpoints, the specific response was only observed in samples that had undergone chlorination as disinfection process. High natural organic matter or other matrix components disturbed the bioassay so much that we recommend it for future routine testing only in tertiary treated water or drinking water.
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Poster #29.

 
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Created: Tue, 09 Apr 2013, 14:02:09 EST by Robyne Anderson on behalf of National Res Centre For Environmental Toxicology