Effects of space flight, clinorotation, and centrifugation on the substrate utilization efficiency of E-colii
Effects of space flight, clinorotation, and centrifugation on the substrate utilization efficiency of E-colii
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DOI：
10.1007/bf02881678
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发表时间：
2002-01-01
影响因子：
1.8
通讯作者：
Todd, P
中科院分区：
文献类型：
--
作者：
Brown, RB;Klaus, D;Todd, P
在太空中生长的大肠杆菌培养物的平均最终细胞数量比相匹配的地面对照高 25% (p < 0.05)。然而，两组消耗的葡萄糖量相同，这表明太空飞行不仅像之前报道的那样刺激了细菌生长，而且还使可用营养物质的利用效率提高了 25%。在旋转下的“模拟失重”中进行的支持实验产生了类似的生长和效率增加的趋势，但绝对值的程度较小。这些实验导致平均最终细胞群增加了 12% 和 9%（p < 0.05），而底物利用效率相对于静态对照提高了 6% 和 9%（分别为 p = 0.12 和 p < 0.05）。相比之下，离心产生的超重力可预见地导致相反的效果——最终细胞数量减少 33% 至 40%，相应的净生长效率降低 29% 至 40% (p < 0.01)。总的来说，这些发现支持了这样的假设：失重条件下观察到的细菌生长增加是由于在没有沉降和浮力驱动的对流的情况下细胞外物质运输减少的结果，这因此也提高了悬浮培养物中的底物利用效率。
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.