ABSTRACT
Biological assays provide important data regarding the bioavailability of toxic agents to living organisms. Observable effects caused by any particular agent under a given set of conditions can be obscured by other toxic agents may be present in the environmental sample. In order to determine the parameters with the high degree of specificity and sensitivity offered by chemical assays, and the ease of use and low cost of in vitro biochemical tests, research efforts have focused on the development of cellular- and molecular-based biosensors. The luminescence assays are relatively inexpensive to perform, and allow for real-time, noninvasive measurement of the expression of specific toxicant-responsive genes. Thus, the capacity to create "luminescent bacterial biosensors" for the detection and measurement of environmental toxicants is proving to be both feasible and practical. The expression of such toxicant-inducible genes can be measured, even if nothing is known about the gene itself, via the use of reporter genes and gene fusion technology.
