Bet-hedging in bacteriocin producing Escherichia coli populations: the single cell perspective.
Production of public goods in biological systems is often a collaborative effort that may be detrimental to the producers. It is therefore sustainable only if a small fraction of the population shoulders the cost while the majority reap the benefits. We modelled this scenario using Escherichia coli populations producing colicins, an antibiotic that kills producer cells' close relatives. Colicin expression is a costly trait, and it has been proposed that only a small fraction of the population actively expresses the antibiotic. Colicinogenic populations were followed at the single-cell level using time-lapse microscopy, and showed two distinct, albeit dynamic, subpopulations: the majority silenced colicin expression, while a small fraction of elongated, slow-growing cells formed colicin-expressing hotspots, placing a significant burden on expressers. Moreover, monitoring lineages of individual colicinogenic cells showed stochastic switching between expressers and non-expressers. Hence, colicin expressers may be engaged in risk-reducing strategies-or bet-hedging-as they balance the cost of colicin production with the need to repel competitors. To test the bet-hedging strategy in colicin-mediated interactions, competitions between colicin-sensitive and producer cells were simulated using a numerical model, demonstrating a finely balanced expression range that is essential to sustaining the colicinogenic population.
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel.
Bihter
B
Bayramoglu
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel.
David
D
Toubiana
Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Ueberlandstrasse 133, 8600 Dübendorf, Switzerland.|Department of Environmental Systems Sciences, ETH Zurich, Universitätsstrasse 16, 8092 Zürich, Switzerland.
Simon
S
van Vliet
Department of Biology, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA.
R Fredrik
RF
Inglis
Department of Physics, Bar Ilan University, Ramat Gan 52990, Israel.
Nadav
N
Shnerb
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel.
Osnat
O
Gillor
D000900:Anti-Bacterial Agents / Q000378:metabolism; D003086:Bacteriocin Plasmids / Q000378:metabolism*; D001430:Bacteriocins / Q000378:metabolism; D003087:Colicins / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods; D008962:Models, Theoretical; D010641:Phenotype; D059008:Time-Lapse Imaging
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D003087:Colicins