Sauer Group, Metabolomics, Screening, Physiology

Tutor: Markus Basan ()

Background

The starting point of this research project is an observed striking correlation between the growth rate of the bacterium E. coli before a medium shift and the resulting lag time when shifted between conditions. We found that switching to the same carbon source, the growth rate on the first carbon source was an excellent predictor of lag time and bacteria growing on fast carbon sources exhibited much longer lag times. These results suggest that for E. coli a tradeoff between fast growth and the ability to switch quickly between carbon sources exists. The general aim of this project is to identify and quantitatively understand the origin of lag times in E. coli in terms of resource allocation, the metabolic state of the cell and regulation. We then want to understand the striking relation between lag times and growth rates and formulate a quantitative and predictive model incorporating both of these objectives.

Your project

While we have made significant progress understanding the origin of lag phase in E. coli, we are now interested in generalizing these findings to other organisms and other pathways. This will significantly broaden the impact of our work. In particular, we want to investigate if similar relations hold for organisms that exhibit lag times from gluconeogenic to glycolytic carbon sources such as Bacillus subtilis and organisms that preferentially utilize gluconeogenic carbon sources like certain soil bacteria.

In the course of your semester project, you will learn how to perform high-throughput physiology screening and measure central metabolite pools and physiological parameters using state-of-the-art techniques (LC – MS / MS, HPLC, micro-cultivation devices). You will perform growth experiments and shifts with various microorganisms. For the most promising growth shifts that we manage to identify, you will perform metabolomics measurements, in order to gain insight into underlying molecular mechanisms and to connect these findings to our previous results and models in E. coli.

Your work will establish the generality of our findings as well as of the underlying mechanisms and therefore will be integrated and published together with our results in E. coli.