In this report, a new method for the selection of tetracycline-sensiti
ve Escherichia coli cells from a mixed population is described. This m
ethod is simpler and more effective than previous methods, does not ut
ilize toxic reagents, and allows selection in liquid as well as solid
media. This method should be of considerable aid in molecular cloning
procedures involving inactivation of the tetracycline-resistance genes
encoding the energy-dependent efflux of the antibiotic, as well as in
the study of the function of tetracycline-resistance elements such as
transposons and integrons. (C) 1996 Academic Press, Inc.