Speaker
Description
Phages and bacteria coexist under various conditions, ranging from liquid cultures to oceans, soil, and the human gut. However, our models are typically limited to well-mixed liquid cultures governed by mass-action kinetics, and the effect of physical structure, such as aggregate formation and spatial structure, is not fully understood. Here, we first discuss modifying the Lotka-Volterra dynamics by including the formation of microcolonies [1]. The model predicts that the colony size distribution is power-low distributed with steeper exponents for the more substantial external influx. In the realistic case where the phage attack rate to individual colonies is proportional to their radius, we obtain self-organization to a steady state where the maximal colony size is smaller for more vigorous external driving. We then introduce the case where the phage T4 attacks the bacteria Escherichia Coli in a spatially structured environment. First, we discuss an experimental analysis of the single spherical colony attacked by phages [2], which indicated that the colony structure marginally protects the bacteria hosts, but the T4 phage is able to penetrate very deep into the bacterial colony. If time allows, we also discuss the effect of lysis inhibition, the phage T4's ability to delay host lysis upon secondary infection, in the spatial spreading of the T4 phage [3].
