S. Belkin et al., MONITORING SUBTOXIC ENVIRONMENTAL HAZARDS BY STRESS-RESPONSIVE LUMINOUS BACTERIA, Environmental toxicology and water quality, 11(3), 1996, pp. 179-185
A novel approach to toxicant detection is described, based on monitori
ng bacterial reactions to environmental threats. In response to such s
tress, various defense mechanisms are turned on by initiating gene tra
nscription at specific DNA sites known as promoters. To follow this tr
anscription sensitively, such promoters were genetically fused in Esch
erichia coli to the lux (luminescence) genes from the bacterium Vibrio
fischeri. The bacteria thus engineered now produce light in response
to different environmental insults; this light is easy to measure and
quantify. A wide range of promoters was utilized in this manner, to cr
eate over a dozen bacterial constructs that emit light in response to
specific or general stress factors. The responses of four of these to
defined chemicals and to wastewater samples are described. The threats
reported by these bacteria include general and protein damage, DNA da
mage, and oxidative hazards (peroxides and oxygen radicals). Members o
f the tested panel exhibited very high sensitivity: generally, the lum
inescent response occurred at subtoxic doses of the stressing factor,
and was evident within 20 min to 2 h after exposure. It is proposed th
at these bacteria, or others constructed in a similar manner, can serv
e as powerful early-warning indicators of environmental pollution, as
well as monitoring tools for the operation of different industrial pro
cesses, from fermentation reactors to wastewater treatment plants. (C)
1996 by John Wiley & Sons, Inc.