1998 Volume 12 Issue 4 Pages 373-376
Distribution of microorganisms and cellular structure of an Autonomous Biological Systems (ABS ) were studied with a special attention to the effect of space environments. Viable cell densities measured by the direct fluorescence microscopic method were in the order of 105 cells⁄ml for fractions 1 (upper suspension) and 2 (lower suspension), and 106 cells⁄ml for fraction 3 (sediments). These values were 10 to 100 times larger than the values obtained by the classical colony forming unit method. No difference between flight and ground samples was observed in the vertical distribution of viable microorganisms when fractionation and analysis were carried out after recovery. Intracellular distribution of chloroplasts in higher green plants, Ceratophyllum demersum, of flight samples was disturbed after 10 days of flight (24hrs⁄day light on). After 4 months of flight (Mir ⁄STS-79⁄81) with 24 hrs light on, Ceratophyllum demersum was completely disintegrated. On the other hand, in the second 4- months-flight experiment with 16 hrs⁄day light on, Ceratophyllum demersum was only slightly deteriorated.
