Physical aspects of bacterial cell division
The growth behavior of a bacterial population is determined by the growth and the division of its individual cells. The properties of the population can be understood as ensemble averages over the properties of the single cells. At the same environmental conditions, these averages have sharp value...
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|The growth behavior of a bacterial population is determined by the growth and the division of its individual cells. The properties of the population can be understood as ensemble averages over the properties of the single cells.
At the same environmental conditions, these averages have sharp values and exhibit minimal variation between different measurements. However, on the single cell level many biological processes, such as gene expression, are intrinsically noisy. This leads to strong deviations in composition and properties of individual cells belonging to the same population.
Recent experimental findings classify the magnitude of these single cell variations, and show that some cellular properties are influenced more by noise than others. For example, the positioning of cell division is very precise compared to other growth properties, which are very diverse. This leads to the question if the population can draw advantages from manually regulating the noise under the respective conditions. To answer this question the influence of single cell noise on the population as a whole has to be observed.
In this thesis, properties and strategies related to bacterial growth and division are discussed. In the observed biological systems, macroscopic properties are deduced from individual properties on the microscopic level. First, the mechanisms are observed that cells use to determine the position of cell division on a molecular level. The simulation of diffusion and reactions of individual proteins determines the behavior on the cellular level. Secondly, the growth of the whole bacterial population is simulated by following the growth and division of single cells. In both systems, the influence of microscopic fluctuations on the complete system is discussed.