Speaker
Namiko Mitarai
(Niels Bohr Institute)
Description
Bacteriophages are viruses that infect bacteria. A virulent
phage infection to a host bacterial cell results in lysis of
the cell and possibly hundreds of phage particle release
after a latency time. It is important for the survival of
bacteria to develop defense mechanisms against phages, while
also for phages it is important not to completely eliminate
their host since bacteria are needed for their propagation.
In this talk, we demonstrate that bacteria growing as a
dense colony provides a spatial refuge by exposing only the
bacterial cells on the surface of the colony to a phage
attack. When the colony size is below a critical size at the
time of exposure to phages, bacteria will be eliminated,
while when the colony size is above the critical size, the
colony can survive and grow despite the persistent phage
attack on the surface. We show that experimental result
using the virulent version of phage P1 and the host
Escherichia Coli is consistent with this prediction. We
study the parameter dependence of the critical size by
numerical simulation, and predict that the phage with lower
adsorption rate will actually kill a colony better. Our
findings indicate that the spatial structure of the
bacterial population plays an important role in
phage-bacteria coexistence.
Reference:
Rasmus Skytte Eriksen, Sine Lo Svenningsen, Kim Sneppen, and
Namiko Mitarai, “A Growing Microcolony can Survive and
Support Persistent Propagation of Virulent Phages”, Proc.
Natl. Acad. Sci. USA. (2018) 115(2):337-342.
