Basal level of ppGpp coordinates Escherichia coli cell heterogeneity and ampicillin resistance and persistence – The universal stringent response alarmone ppGpp (guanosine penta and tetra phosphates) plays a crucial role in various aspects of fundamental cell physiology (e.g., cell growth rate, cell size) and thus bacterial tolerance to and survival of external stresses, including antibiotics. Besides transient antibiotic tolerance (persistence), ppGpp was recently found to contribute to E. coli resistance to ampicillin. How ppGpp regulates both the persistence and resistance to antibiotics remains incompletely understood. In this study, we first clarified that the absence of ppGpp in E. coli (ppGpp0 strain) resulted in a decreased minimal inhibition concentration (MIC) value of ampicillin but, surprisingly, a higher persistence level to ampicillin during exponential growth in MOPS rich medium. High basal ppGpp levels, thus lower growth rate, did not produce high ampicillin persistence ()
Phenotypic heterogeneity in mycobacterial stringent response, BMC Systems Biology
p)ppGpp levels are regulated by RSH proteins. (A) Rel, RelA, and
SpoT activity is regulated through ACP interactions.
Understanding the Stringent Response: Experimental Context Matters
Molecular Microbiology, Microbiology Journal
Many Means to a Common End: the Intricacies of (p)ppGpp Metabolism and Its Control of Bacterial Homeostasis
Basal levels of ppGpp are increased in VRE strains harboring
Escherichia coli can survive stress by noisy growth modulation
Phenotypic heterogeneity in persisters: a novel 'hunker' theory of