Abstract
Organophosphate (OP) pesticides cause hundreds of illnesses and deaths annually. Unfortunately, exposures are often detected by monitoring degradation products in blood and urine, with few effective methods for detection and remediation at the point of dispersal. We have developed an innovative strategy to remediate these compounds: an engineered microbial technology for the targeted detection and destruction of OP pesticides. This system is based upon microbial electrochemistry using two engineered strains. The strains are combined such that the first microbe (E. coli) degrades the pesticide, while the second (S. oneidensis) generates current in response to the degradation product without requiring external electrochemical stimulus or labels. This cellular technology is unique in that the E. coli serves only as an inert scaffold for enzymes to degrade OPs, circumventing a fundamental requirement of coculture design: maintaining the viability of two microbial strains simultaneously. With this platform, we can detect OP degradation products at submicromolar levels, outperforming reported colorimetric and fluorescence sensors. Importantly, this approach affords a modular, adaptable strategy that can be expanded to additional environmental contaminants.
Highlights
The organophosphate (OP) pesticides parathion and paraoxon cause thousands of illnesses and deaths annually, as they have the same mechanism of action as the nerve gas sarin.[1−4] Such compounds disrupt the native neurotransmitter acetylcholine[5,6] and impact the parasympathetic nerve system, which can be deadly.[1−4] Similar compounds were employed as chemical weapons during World War II in the form of sarin, cyclosarin, and soman
We have used the surface of E. coli as a platform to display organophosphate hydrolase (OPH) for OP degradation
Our results demonstrate that the OPH expressed on E. coli can degrade a variety of OPs, albeit with differing efficiencies
Summary
The organophosphate (OP) pesticides parathion and paraoxon cause thousands of illnesses and deaths annually, as they have the same mechanism of action as the nerve gas sarin.[1−4] Such compounds disrupt the native neurotransmitter acetylcholine[5,6] and impact the parasympathetic nerve system, which can be deadly.[1−4] Similar compounds were employed as chemical weapons during World War II in the form of sarin, cyclosarin, and soman. Physical and chemical decontamination strategies have been developed for the capture or degradation of OPs,[1] enzymatic methods are popular due to their substrate promiscuity, ability to directly degrade these compounds, and ready incorporation into genetically modified organisms (GMOs). Organophosphate hydrolases (OPHs) are extensively used because of their compatibility with recombinant expression and with incorporation into biomaterials.[1,14,15]. OPH can be challenging to work with due to its tendency to aggregate.[16−18] Polymer encapsulation has been used to improve protein stability and delivery[19−31] but still requires challenging protein isolation and purification prior to deployment
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