Quantitative bioassay using laser-monitored bacteria to assess toxicology and metabolism of bioactive Group IV compounds.

A new approach has been developed for assessing the toxicity and the metabolism of Group IV compounds and for other toxic substances that may interact with them at the molecular level. The approach is based upon the selective responses of sensitive biodetectors whose molecular interactions with a wide variety of toxic substances have been previously described and reported. Detection and quantitation of carbon, silicon, and tin-containing compounds has been accomplished using a laser-monitored bacterial bioassay. This system uses isogenic Bacillus subtilis strains that are genetically engineered to respond differentially to specific toxicants. The response of these biodetectors is monitored by differential light scattering of a laser that is integrated with a computerized system which collects and analyzes this data. The assay can routinely generate fully analyzed data for fixed time intervals, i.e. 60 or 90 min, or kinetic data so that the mechanisms of interactions can be elucidated.