RESUMO
Lysogenic strains of Escherichia coli were exposed to space conditions aboard the flight of Zond 5 and Zond 7. Space flight factors appeared to affect the state of episome systems of bacteria, as judged by data obtained with F-Lac+ donor cells which also carried genetic markers for threonine and leucine. Observations on phage induction are discussed and compared with results obtained aboard Biosatellite 2. A number of monolayer cultures of human cells (HeLa cells, fibroblasts, and A-1 cells) were repeatedly exposed to the space environment. In one instance, HeLa 19 cells increased in size after exposure to space conditions, a change which appeared to be genetically stable. HeLa 19 cells which were carried on six separate space flights showed a higher viability than corresponding cultures which were exposed only once aboard Zond 5.