Hfq Positively Regulated the Proliferation Ability of Escherichia coli K-12 Under Simulated Microgravity Condition

Abstract

Simulated microgravity enhances Escherichia coli (E. coli) proliferation ability, but the underlying mechanisms remain unclear. In this study, we cultured E. coli in a three-dimensional rotational environment for 14 days to establish simulated microgravity strains (SMG). Compared to normal gravity strains (NG), SMG exhibited enhanced growth rate, and motility. Hfq plays a crucial role in proliferation ability in terms of growth rate and motility in E. coli. And it is worth noting that, compared with the NG, the expression of hfq in E. coli was upregulated in SMG. The expression of genes including minD, minE, flhC and flhD upregulated in SMG. To investigate the effect of hfq on E. coli proliferation ability, we knocked out hfq in E. coli to establish a Δhfq E. coli strain and cultured it under simulated microgravity conditions for 14 days (Δhfq SMG). The Δhfq SMG exhibited reduced growth rate and motility compared to SMG. Meanwhile, the expression levels of minD, minE, flhC and flhD were downregulated. Replenishing hfq to Δhfq SMG could restore growth rate and motility, and re-activate the downregulated genes. In conclusion, it is demonstrated that hfq played a significant role in the proliferation ability of E. coli under simulated microgravity condition and this effect might be closely related to the proliferation ability -related genes of E. coli. This study may provide a new idea for preventing and controlling opportunistic pathogenic bacterial infections during aerospace missions.