Detection sensitivity of Gluc secreted by bacteria recovered from <i>in vivo</i> infection increases with CTZ concentration, but is less affected by integration time.

<p>All results have been normalized with OD₆₀₀. (A) <i>E. coli</i> clone 6189 (ML6189) was grown in LB medium for 16 hr and secreted Gluc in culture supernatant was measured as the “before infection” sample. <i>E. coli</i> from the above culture was used for mice thigh infection. 24 hr later, <i>E. coli</i> was recovered from infected thigh tissues and grown as colonies on Agar plate. 7 colonies were randomly picked from the plate and inoculated into LB for 16 hr. Culture supernatant of the above 7 colonies was measured for secreted Gluc activity. CTZ: coelenterazine, substrate of Gluc. For panel A, integration time for Gluc assay is 1000 millisecond (ms). (B) For panel B, 39 µM CTZ was used for Gluc assay. Overnight culture supernatant of the 7 colonies recovered from mice infection was measured for secreted Gluc activity.