CARBON STARVATION OF SALMONELLA-TYPHIMURIUM DOES NOT CAUSE A GENERAL INCREASE OF MUTATION-RATES

Mutation rates in bacteria can vary depending on the genetic target st udied and the specific growth conditions of the cells, Here, two diffe rent methods were used to determine how rates of mutation to antibioti c resistance, auxotrophy, and prototrophy were influenced by carbon st arvation on agar plates, The rate of mutation to rifampin resistance w as increased by starvation as measured by fluctuation tests, similar t o what has been reported previously for Escherichia coil. In contrast, the rates of mutation to various types of auxotrophy were unaffected or decreased as measured by both fluctuation tests and a repeated-stre aking procedure, Similarly, the rates of reversion to prototrophy of h is and lac nonsense and missense mutations were unaffected by starvati on, Thus, mutation rates of different genetic targets can be affected differently by starvation and we conclude that carbon starvation is no t generally mutagenic in Salmonella typhimurium.