The induction of growth-altered cell populations (tumor-initiation sites) in rat tracheal implants exposed to benzo[a]pyrene and formaldehyde.

The effects of exposure to benzo[a]pyrene (BAP) and formaldehyde (HCHO), alone and combined, on the induction of carcinogenesis in rat tracheal implants was determined as the number of growth-altered cell populations (tumor-initiation sites, TIS) per trachea. While exposure twice-weekly for 4.5 months to 0.

Mutations in Escherichia coli that effect sensitivity to oxygen.

Fifteen oxygen-sensitive (Oxys) mutants of Escherichia coli were isolated after exposure to UV light. The mutants did not form macroscopic colonies when plated aerobically. They did form macroscopic colonies anaerobically.