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Effects of space flight, clinorotation, and centrifugation on the substrate utilization efficiency of E. coliCultures 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.
Document ID
20040104060
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Brown, Robert B.
(robmarlabrown@earthlink.net)
Klaus, D.
Todd, P.
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Publication Information
Publication: Microgravity science and technology
Volume: 13
Issue: 4
ISSN: 0938-0108
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: NCC8-131
Distribution Limits
Public
Copyright
Other
Keywords
manned
short duration
Flight Experiment
STS-95 Shuttle Project

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