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TY - JOUR AU - Marshall, Bonnie AU - Levy, Stuart B. PY - 1980 DA - 1980/07/01 TI - Prevalence of amber suppressor-containing coliforms in the natural environment JO - Nature SP - 524 EP - 525 VL - 286 IS - 5772 AB - Amber suppressible genes have been introduced into vectors1,2 and proposed for use in recombinant DNA studies. Such genes can be expressed only in a host bacterium with amber suppressors. To assess the biological containment of this kind of mutation we have now examined the frequency of bacteria with amber suppressors in faecal samples from humans and animals in different environments. This approach allowed us to evaluate the number of individuals in an environment bearing bacteria with amber suppressor mutations and the frequency of these bacteria within the faecal samples of each individual. Of all individuals sampled 30.5% contained detectable levels of bacteria with amber suppressor activity. In >75% of these samples, the level of suppressor-containing bacteria was <10%, about half of which were <1%. Most of these were Escherichia coli: however, Citrobacter and Klebsiella were also found. In three samples, essentially all coliforms had suppressor activity. Excluding these three samples, the estimated frequency of amber suppressors among faecal coliforms was 1.5%; however, if the data from these individuals were included, the overall frequency among faecal samples could be as high as 10%. By itself, the finding suggests that amber suppressor mutations in recombinant DNA vectors may not offer as great a safety feature as originally considered. These data, however, must be considered together with the known low sensitivity of wild-type E. coli to laboratory phages3,4 and their low recipient ability for some plasmids. SN - 1476-4687 UR - https://doi.org/10.1038/286524a0 DO - 10.1038/286524a0 ID - Marshall1980 ER -