טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentSusman Lee
SubjectMulti-dimensional phenotype and long-term dynamics in
individual bacteria
DepartmentDepartment of Applied Mathematics
Supervisor Professor Naama Brenner


Abstract

Genetically identical microbial cells typically display significant variability in every measurable property. In particular, highly abundant proteins - which can determine cellular behavior exhibit large variability in copy number among individuals. Their distribution has a universal shape common to different proteins and microorganisms; the same distribution shape is measured both in populations and in single-cell temporal traces. Moreover, different highly expressed proteins are statistically correlated with cell size and with cell-cycle time. These results indicate
coupling between measurable properties in the cell and buffering of their statistics from the microscopic scale. We propose a modeling framework in which the complex intracellular processes produce a phenotype composed of many effectively interacting components. These interactions, as well as the imperfect nature of cell division events, provide a simple model that reconstructs many properties of phenotypic variability on several timescales. These include fluctuating accumulation rates along consecutive cell-cycles, with correlations among the rates of phenotype components; universal and non-universal properties of distributions; correlations between cell-cycle time and different phenotype components; and temporally structured autocorrelation functions with long (
10 generation) timescales.