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Overview
Synthetic organophosphorus (OP) compounds, which are highly toxic contaminants in agro-environment and food security, have been widely applied to pesticides. Parathion is a typical representative of organophosphorus pesticides. This year, our goal is to construct a p-Nitrophenol sensor in E.coli, which is the degradation product of parathion, in order to reflect the existence of parathion. Besides, we try constructing a degradation system to solve the pollution problem. Considering the biosafety problem, we also design a suicide system in which the lethal genes are only triggered by declining p-Nitrophenol concentration. This will enable the bacteria to commit suicide when p-Nitrophnol is sufficiently degraded.
Our Project
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OP Degradation
The bacterial organophosphorus hydrolase enzyme hydrolyzes and detoxifies a broad range of toxic organophosphate pesticides. In the first part, we need to use these enzymes to degrade parathion into PNP.
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PNP Sensor
The second part is a biosensor of the hydrolysis product P-Nitrophenol (PNP). There is no operon that can react to parathion. We foucus on constructing a PNP sensor, which can reflect the existence of parathion.
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PNP Degradation
We also design a PNP degradation system. We use enzymes NphA1 and NphA2 to degrade PNP, but fail. We find another pathway to degrade PNP in 5 steps with 4 enzymes in Rhodococcus sp. Strain PN1.
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Suicide System
With the public increasingly concerned about biosafety, we conceived a suicide gene circuit to ensure these recombinanational bacteria can only survive in laboratories and not cause horizontal gene transfer.
