M.Sc Thesis


M.Sc StudentStawsky Alejandro
SubjectMultiple Timescales in Bacterial Growth
Homeostasis
DepartmentDepartment of Applied Mathematics
Supervisor PROF. Naama Brenner


Abstract

Experimental variability of single-cell bacterial growth has been largely reduced due to the tight control provided by the microfluidic setup of the mother machine. As a result, most analysis is done on an ensemble of bacteria pooled from many old-pole lineages. This is done under the assumption that the lineages themselves behave as sets of bacteria sampled independently from the pooled ensemble. In this work we show evidence of the contrary. We find that, for certain physiological variables, lineages are so localized in phase-space that their time-averages can explain up to 45% of the variance from the pooled ensemble. Using a new microfluidic machine that follows two lineages growing in the same trap at the same time, we were able to attribute this localization, at least in part, to the micro-environment of a trap. Furthermore, we report across a vast array of experiments persistent and non-persistent temporal fluctuations consistent with the average behavior of the lineages. We define a 3D manifold on which the lineage time-averages lie and explain what our results mean with respect to the analysis of size regulation in bacteria.