Oxidative stress detection with Escherichia coli harboring a katG'::lux fusion.
A plasmid containing a transcriptional fusion of the Escherichia coli katG promoter to a truncated Vibrio fischeri lux operon (luxCDABE) was constructed. An E. coli strain bearing this plasmid (strain DPD2511) exhibited low basal levels of luminescence, which increased up to 1,000-fold in the presence of hydrogen peroxide, organic peroxides, redox-cycling agents (methyl viologen and menadione), a hydrogen peroxide-producing enzyme system (xanthine and xanthine oxidase), and cigarette smoke. An oxyR deletion abolished hydrogen peroxide-dependent induction, confirming that oxyR controlled katG'::lux luminescence. Light emission was also induced by ethanol by an unexplained mechanism. A marked synergistic response was observed when cells were exposed to both ethanol and hydrogen peroxide; the level of luminescence measured in the presence of both inducers was much higher than the sum of the level of luminescence observed with ethanol and the level of luminescence observed with hydrogen peroxide. It is suggested that this construction or similar constructions may be used as a tool for assaying oxidant and antioxidant properties of chemicals, as a biosensor for environmental monitoring and as a tool for studying cellular responses to oxidative hazards.
Belkin
S
S
Desert Research Institute, Ben-Gurion University of the Negev, Sede-Boqer, Israel. belkin@bgumail.bgu.ac.il
Smulski
D R
DR
Vollmer
A C
AC
Van Dyk
T K
TK
LaRossa
R A
RA
D001426:Bacterial Proteins; D001483:Base Sequence; D015374:Biosensing Techniques; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D049449:Luminescence; D008969:Molecular Sequence Data; D009876:Operon; D018384:Oxidative Stress; D010544:Peroxidases / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D012906:Smoke; D014733:Vibrio / Q000235:genetics
D001426:Bacterial Proteins; D017931:DNA Primers; D012906:Smoke; D006861:Hydrogen Peroxide; D010544:Peroxidases; C076136:catalase HPI