Abstracts

Pesticide contamination in food and environment is a major problem in Thailand and many countries around the world because it can cause long-term negative effects on human health. We have developed an enzymatic cascade reaction to degrade various pesticides and change them into firefly luciferin derivatives (~51% yield) which are widely used in detection applications. We have shown that the bioluminescence of novel luciferins is red-shifted with maximum emission at 663 nm (5’,7’-dimethoxy luciferin, 5’,7’-DiOMeLH₂). Reactions of 5’-methyl luciferin (5’-MeLH₂) and 5’,7’-dimethyl luciferin (5’,7’-DiMeLH₂) with various beetle luciferases provide higher light intensity than that of natural D-luciferin. Remarkably, the novel 5’,7’-DiOMeLH₂ and 5’,7’-DiMeLH₂ give steadily light emission with a slower rate of light decay (3.2-fold) than D-luciferin. These novel luciferins thus can provide substantially stronger bioluminescence that the natural D-luciferin, making them useful and suitable for various applications including real-time bioluminescence imaging. Moreover, we have developed the enzymatic reaction to detect pesticide contamination in food, environmental, and biological samples called Luminescence-related Method for Specific detection (LUMOS). LUMOS technology provides high sensitivity of detection in a range of ppt levels with the accuracy comparable to the gold standard methods of using HPLC-MS. We have used LUMOS technology in local communities in northern Thailand as a surveillance tool to detect pesticide contamination in food and environmental samples.