Spontaneous mutation in a thermoacidophilic archaeon: evaluation of genetic and physiological factors

We used direct selection of pyrE and pyrF mutants to estimate the rates of spontaneous mutation in Sulfolobus acidocaldarius as a function of genetic background and culture conditions. Fluctuation tests were applied to several genetically marked strains, including one isolated as a putative mutator strain, and to cultures grown over a wide range of temperature and other physiological conditions. The results suggested some impact of auxotrophic markers on the apparent rate of mutation, but no obvious pattern of effect of growth conditions, including those that gave evidence of being physiologically stressful. Received: 27 May 1997 / Accepted: 2 September 1997