Microbial Sensors of Ultraviolet Radiation Based on recA'::lux Fusions

Abstract

Escherichia coli strains containing plasmid-borne fusions of the recA promoter-operator region to the Vibrio fischeri lux genes were previously shown to increase their luminescence in the presence of DNA damage hazards, and thus to be useful for genotoxicant detection. The present study expands previous work by demonstrating and investigating the luminescent response of these strains to ultraviolet radiation. Several genetic variants of the basic recA'::lux design were examined, including a tolC modification of membrane efflux capacity, a chromosomal integration of the recA'::lux fusion, a different lux reporter (Photorhabdus luminescens instead of V. fischeri, allowing the assay to be run at 37 degrees C), and a different host bacterium (Salmonella typhimurium instead of E. coli). Generally, two modifications provided the fastest responses: the use of the S. typhimurium host or the P. luminescens lux reporter. Highest sensitivity, however, was demonstrated in an E. coli strain in which a single copy of the V. fischeri lux fusion was integrated into the bacterial chromosome.

Alkylresorcinols Protect the DNA from UV-Damage In Vitro and In Vivo Models

“…At studying of SOS-system activity the recombinant bioluminescent strain of Escherichia coli recA'::lux containing plasmid-borne fusions of the recA promoter-operator region to the Photorhabdus luminescens ZM 1 lux genes (GosNIIgenetika, Russia) was used. Increase of their luminescence in the presence of DNA damage factors [Rosen et al, 2000], were shown previously. Investigation of the luminescent response of this strain to UV radiation allows quantitatively estimate in a real time a SOS-system induction.…”

Stress-Based Identification and Classification of Antibacterial Agents: Second-Generation Escherichia coli Reporter Strains and Optimization of Detection

“…A hallmark of the exposure of E. coli to conditions or agents that lead to DNA damage is the induction of the SOS response (42). Because SOS induction occurs primarily at the transcriptional level, fusions between the recA, uvrA, sulA, dinD, or cda promoters and the Vibrio fischeri luxCDABE (12) and for the detection of bioantimutagens (35), UV irradiation, and genotoxins (5,25,27,28,41). Here, we selected the SOS-inducible promoter of the cell division inhibitor SulA since a -borne sulA::lacZ fusion is available (30) and because sulA is the most tightly repressed and highly inducible SOS gene characterized to date (32).…”

The role of SOS boxes in enteric bacteriocin regulation

“…recA promoter served as a positive control, as it is SOSregulated and induced by numerous DNA-damaging agents, including MitC Rosen et al, 2000;Van Dyk et al, 2001a). Following a short lag phase, induction of the wild-type Pce1a was rapid and reached a response ratio of 80 within 2.5 h. The single mutant retaining the non-consensus LexA binding site (2/+) had a pattern of induction similar to that observed for the wildtype promoter, but with a 17-fold lower response ratio.…”