RAPID AND SENSITIVE POLLUTANT DETECTION BY INDUCTION OF HEAT-SHOCK GENE-BIOLUMINESCENCE GENE FUSIONS

Heat shock gene expression is induced by a variety of environmental st resses, including the presence of many chemicals. To address the utili ty of this response for pollutant detection, two Escherichia coli heat shock promoters, dnaK and grpE, were fused to the lux genes of Vibrio fischeri. Metals, solvents, crop protection chemicals, and other orga nic molecules rapidly induced light production from E. coli strains co ntaining these plasmid-borne fusions. Introduction of an outer membran e mutation, tolC, enhanced detection of a hydrophobic molecule, pentac hlorophenol. The maximal response to pentachlorophenol in the tolC(+) strain was at 38 ppm, while the maximal response in an otherwise isoge nic tolC mutant was at 1.2 ppm. Stress responses were observed in both batch and chemostat cultures. It is suggested that biosensors constru cted in this manner may have potential for environmental monitoring.