Studies

A set of isogenic mutant strains was constructed which lack NADH Dehydrogenase I as well as two terminal oxidases, resulting in strains with linear respiratory chain. The different strains hence differ in the terminal oxidase and express either cytochrome bo, cytochrome bdI or cytochrome bdII. The different strains were cultivated in glucose-limited chemostats with defined low levels of oxygen supply. Biomass and by-product formation, gene expression and the phosphorylation state of the important ...

Mutant strains in which one or more of the potential glucose uptake systems was deleted have been analyzed in aerobic and anaerobic batch cultures, as well as aerobic chemostat cultures.

Goals:

1. Understanding the regulatory principles of Escherichia coli’s electron transport chain (ETC) for varying oxygen conditions in glucose-limited continuous cultures (especially regulatory loops via the transcription factors FNR and ArcA).
2. Explaining the observed phenomena in the measurement data.
3. Predicting unmeasured variables especially of the gene expression regulatory loops.

Means:

1. Experiments (chemostat experiments within the aerobiosis scale).
2. Kinetic modelling (especially ...

Mutant strains which carry deletions of important metabolic enzymes, as well as mutant strains with altered regulation, need to adapt by changing fluxes or gene expression to compensate with the absence/differed concentration of these key enzymes. This may give new insights in the regulation of these pathways/enzymes.