In vivo detection of endogenous toxic phenolic compounds of intestine.

Phenol and p -cresol are two common toxic small molecules related to various diseases. Existing reports confirmed that high L -tyrosine in the daily diet can increase the concentration of phenolic compounds in blood and urine. L-tyrosine is a common component of protein-rich foods. Some anaerobic bacteria in the gut can convert non-toxic l-tyrosine into these two toxic phenolic compounds, phenol and p -cresol. Existing methods have been constructed for measuring the concentration of phenolic compound in feces. However, there is still a lack of direct visual evidence to measure the phenolic compounds in the intestine. In this study, we aimed to construct a whole-cell biosensor for phenolic compounds detection based on the dmpR , the regulator from the phenol metabolism cluster. The commensal bacterium Citrobacter amalonaticus PS01 was selected and used as the chassis. Compared with the biosensor based on ECN1917, the biosensor PS01[ dmpR ] could better implant into the mouse gut through gavage and showed a higher sensitive to phenolic compound. And the concentration of phenolic compounds in the intestines could be observed with the help of in vivo imaging system using PS01[ dmpR ]. This paper demonstrated endogenous phenol synthesis in the gut and the strategy of using commensal bacteria to construct whole-cell biosensors for detecting small molecule compounds in the intestines. [Display omitted] • A plasmid for detecting phenol and p -cresol was constructed. • The biosensor was constructed with a native bacterium chassis from the host. • The limit of quantitation of the biosensor was 948.4 nmol/L for phenol and 9.52 µmol/L for p -cresol. • The whole biosensor could be used in vivo to detect the level of toxic phenolic compounds in the host. [ABSTRACT FROM AUTHOR]