VIABILITY AND MORPHOLOGY OF HALOBACTERIUM SPECIES FOLLOWING DESICCATION - IMPLICATIONS FOR CONTAMINANTS ON MARS

摘要

A very low moisture content is characteristic of the Martian atmosphere; it is therefore of interest to explore the survival capabilities of microorganisms in conditions of low water activity. Two Halobacterium salinarum strains (DSM 3754, DSM 670) were embedded in salt crystals by reducing the water content of cultures. The viability was tested by spread plating on agar and the morphology was visualized following staining with 4,6′-diamidino-2-phenylindole (DAPI). Most cells appeared roundish, following embedding in salt, depending on the buffer used and the time of incubation. Cfu's on agar indicated approximately 1% survivors. The results suggested that low water activities are well tolerated by haloarchaea, affecting only minimally their survival capacity. If this tolerance extends to other (terrestrial) microorganisms, extant contaminants on Mars can be expected to remain in a viable state.