Abstract: Disclosed herein is a novel forward mutation assay based on 5-fluorouracil (5-FU) resistance which utilizes a strain of Salmonella typhimurium derived from the Ames strain TA100. More specifically, the invention provides a high throughput alternative to the standard Ames mutation assay for the evaluation of the genotoxicity activity of compounds during an early stage of the drug development process. The invention also identifies the upp locus as a mutational target that is capable of detecting a diverse spectrum of mutagenic events and further describes a S. typhimurium tester strain, designated FU100 (his+, rfa, ?uvrB, pkM101, 5-fluorouridine resistant) for use in the assay of the invention.

Abstract: An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to diploid human lymphoblastoid cell lines. The gene locus employed for this assay is the gene for thymidine kinase, uridine kinase, or cytidine deaminase. Since human lymphoblastoid cells contain two genes for these enzymes, heterozygotes of human lymphoblastoid cells are used in this assay.

Abstract: An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to bacterial cells such as Salmonella typhimurium. After administration of or exposure to a mutagenic agent, the bacterial cells are plated in the presence of a purine analog and resistance to purine analogs is used as the genetic marker. This bioassay system can be used by genetic toxicologists to determine the potential genetic hazards from the use of a variety of suspected or known mutagens, including newly-developed chemicals.