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A quantitative approach to microbial population growth using tailored cylindrical yeast colonies
Microbes can form complex structures composed of millions to billions of cells. These assemblies contrast with the classical view we have of the “unicellulars” microbes. In fact, given their environment, they likely form heterogeneous connected structures, and our understanding of these assemblies is still scarce. The problem is that the models we develop suffer from the lack of experimental tools to understand these groups of cells. In this seminar, I propose to study the yeast Saccharomyces cerevisiae colonies by defining the flux of nutrients the colony receives. I use patterned filtration membranes intercalated between colonies and nutritive gel, leading to well controlled shapes. Using the cylindrical geometry resulting from a disc pattern, propose a simple model for colony growth in order to explain experimental results from different environmental conditions, with respect to glucose levels, colony diameter and oxygen availability. I will then discuss the biological relevance of this model with respect to cell division and nutrient absorption. To go further in investigations, I propose a automated measure of colony volume using a laser based measure with a 10 µm height precision. A microfluidic setup that mimics a two-dimensional colony growth is also proposed, where cells can be directly observed under a microscope.