Publication Date:
2019-07-13
Description:
Cultures of Escherichia coli grown in space reached a 25% higher average final cell population than those in comparably matched ground controls (p〈0.05). However, both groups consumed the same quantity of glucose, which suggests that space flight not only stimulated bacterial growth as has been previously reported, but also resulted in a 25% more efficient utilization of the available nutrients. Supporting experiments performed in "simulated weightlessness" under clinorotation produced similar trends of increased growth and efficiency, but to a lesser extent in absolute values. These experiments resulted in increases of 12% and 9% in average final cell population (p〈0.05), while the efficiency of substrate utilization improved by 6% and 9% relative to static controls (p=0.12 and p〈0.05, respectively). In contrast, hypergravity, produced by centrifugation, predictably resulted in the opposite effect--a decrease of 33% to 40% in final cell numbers with corresponding 29% to 40% lower net growth efficiencies (p〈0.01). Collectively, these findings support the hypothesis that the increased bacterial growth observed in weightlessness is a result of reduced extracellular mass transport that occurs in the absence of sedimentation and buoyancy-driven convection, which consequently also improves substrate utilization efficiency in suspended cultures.
Keywords:
Aerospace Medicine
Type:
Microgravity science and technology (ISSN 0938-0108); 13; 4; 24-9
Format:
text
Permalink
