Discovery of the Quiescent Body that Functions as a Biological Timer for Growth Resumption of Non-growing Bacterial Cells

Bacterial cells take a variable lag time and maintain a multi-drug tolerant non-growing state before resuming growth when encountering growth-supportive conditions. Some of them exhibit an extraordinarily long lag, as pathogenic persisters do. It remains unknown on what determines lag time duration. Here, we unveiled a subcellular structure, termed quiescent body, that is formed in bacterial cells entering non-growing state and sequesters selected proteins essential for cell growth. Their formation occurs progressively in each cell and heterogeneously among individual cells. They only dissolve in re-growing cells to release proteins for immediate re-functioning when conditions become fit. Quiescent body, whose degree of formation is highly correlated with duration of lag time or level of antibiotic tolerance, apparently functions as a biological timer for bacterial growth resumption. Further, suppressing their formation, which directly relies on cellular respiration complexes, or promoting their dissolution might be a viable strategy to eradicate persisters.