Arieh Zaritsky
Ben-Gurion University of the Negev, Israel
Title: Multiplication of virulent bacteriophage: Interactions with the host
Biography
Biography: Arieh Zaritsky
Abstract
Dependence of virulent (bacterio) phage multiplication on the physiological state of its host, conceived in the 1940’s,was refi nedfor the T4/Escherichia coli model system.Th e knownkinetic parameters (adsorption rate, eclipse and latent periods, ripening-rate, and consequent burst size) are relatedsolely to the host’s physiological state expressed by the bacterial growth rate before infection.Numerical models were advanced to explain (a)dependence of phage multiplication dynamics on host’s physiology, (b) co-existence of phage and its susceptible bacteria based on phage suicideand (c) kinetics of cell lysis based on materials corrosion, statistics of extremes and updated knowledge on bacterial physiology and phage biology. A mathematical model (d) was devisedto maximize phage titers by adjusting values of bacterial doubling time and initial multiplicity of infection (MOI). Results display a range of possible values along a golden strip in the relevant plane, and times to achieve these maxima and gains were evaluated.Resolution of the adsorption kinetics was refi ned (e) by frequent (~5 min-1) sampling at MOI=1 during the fi rst 6 min. Th e observed fast drop in free phage and bacteria is consistent with a relatively simple model. Th e sharper reduction in viable cells indicates that adsorption is more complex than thought to be.Th e consistencies of the various models with existing experimental resultssupport predictability and potential use to improve phage therapy.