8 - SOS Chromotest and the Use of Bacteria for the Detection and Diagnosis of Genotoxic Agents

Abstract

Publisher Summary The SOS system is a network responding to a wide variety of DNA lesions; thus, the corresponding tester strain detects a wide spectrum of different genotoxic agents and is useful in screening programs. Bacteria played an essential role in the origin of short-term tests designed to detect genotoxic agents. Bacterial cells are widely used not only in screening programs but also for the analysis of the molecular mode of action of genotoxic agents. Genotoxic agents are able to damage DNA. In the early tests, the bacterial response monitored after the action of a genotoxic agent was a late and macroscopic consequence of the original damage, such as the production of a temperate phage or of bacterial mutants. Bacterial cells contain elaborate genetic networks to respond to DNA damage. These are able to sense DNA lesions and to adapt their response to the type and extent of the damage. Many genes in these networks are, thus, inducible by genotoxic agents. The induction of the expression of these genes can be taken as early signals for the existence of DNA damage. By monitoring the induction of these genes, the bacterial cells are used as sensors to provide early signals for DNA damage.