模拟失重对大肠杆菌K12基因表达及表型的影响

【目的】通过低剪切力模拟失重(Low-shear modeled microgravity,LSMMG)连续传代培养大肠杆菌,检测大肠杆菌在模拟失重条件下的表型变化及基因改变。【方法】利用旋转细胞培养系统模拟失重环境对大肠杆菌K12进行连续传代培养,对菌株进行增殖速率、耐酸性和生物膜形成的测定,以此评估LSMMG对大肠杆菌K12表型的影响。利用转录组测序检测模拟失重条件下差异表达的基因,与表型作比对。【结果】模拟失重导致大肠杆菌增殖速率降低,耐酸性下降,生物膜形成能力增强;模拟失重条件下,营养代谢相关差异表达基因有25个,其中20个表达下降,2个与耐酸相关基因表达均下降。【结论】模拟失重会引起大肠杆菌表型及相应的基因变化,其中生物膜形成能力的增强可能对航天飞行造成潜在威胁。

Effect of microgravity on Escherichia coli K12 phenotype and gene expression

[Objective] To reveal the phenotypic and gene expression change of Escherichia coli after exposure to microgravity. [Methods] Rotary cell culture system (RCCS) was used to simulate microgravity environment. The effect of microgravity on E. coli K12 was estimated by measuring the growth kinetics, acid resistance and biofilm formation. RNA-Seq was applied to detect the change of gene expression under low shear modeled microgravity (LSMMG). [Results] LSMMG weakened the growth and acid resistance of E. coli K12 and strengthened the biofilm formation ability. Twenty of 25 genes related to nutrition metabolism and the only two acid resistance related genes were down regulated under LSMMG condition. [Conclusion] Simulated microgravity would lead to a certain change of phenotype and corresponding genes. The enhanced biofilm formation and cytotoxicity would be the potential threats of space flight.