12th International Symposium on Bioluminescence & Chemiluminescence

Symposium abstracts:

Monitoring promoter activity in bacterial cells by using green and red fluorescent proteins

Virta, Marko, Hakkila, Kaisa, Maksimow, Mikael, Rosengren Arsi, Karp, Matti

Dept. of Biotechnology, University of Turku, Turku, Finland. Email: marvirta@utu.fi

In this work we wanted to investigate the possibility of monitoring promoter activity with flow cytometry by using fluorescent proteins GFPmut2 and DsRed in a single bacterial cell. DsRed was expressed from lac promoter/operator and GFPmut2 from mer promoter/operator, which is inducible with Hg2+ ions. The DsRed was used as a marker of the single Escherichia coli MC1061 cell and GFPmut2 was used in monitoring of promoter activity. The expression of dsred was constitutive, because the host strain MC1061 lacks the lacI gene. Cells were analysed with flow cytometer by using 488 nm argon laser for excitation and with Wallac Victor fluorometer.
Over 75 % of the cells emitted red and green fluorescence. Green fluorescence increased when the concentration of mercury was increased.
Results here show that gfp and dsred could be expressed under different promoter in the same bacterial cell and measured independently with flow cytometer.

This is a preprint of an article accepted for publication in Luminescence: Copyright 2001 John
Wiley & Sons, Ltd (Wiley website)