ESCHERICHIA-COLI METABOLISM IN SPACE

Cultures of the bacterium Escherichia coli were grown in the orbiting Biocosmos 2044 satellite in order to evaluate the effects of the space environment - weightlessness and heavy particle radiation - on growth parameters and energy metabolism, which have previously been reported to be affected, and on induction of the SOS response, which reflects DNA damage to the cell. We found no differences between the flight samples and control ground cultures in the growth yield per gram of carbon, in mean cell mass (from which we deduce that the growth rate was unaltered) or in the level of expression of the SOS response. These observations indicate that free-growing bacterial cells do not expend significant energy fighting gravity and that cosmic radiation within a space capsule does not produce significant levels of DNA damage.