Michael Ederer

"Systems Understanding of Microbial Oxygen responses" (SUMO) investigates how Escherichia coli senses oxygen, or the associated changes in oxidation/reduction balance, via the Fnr and ArcA proteins, how these systems interact with other regulatory systems, and how the redox response of an E. coli population is generated from the responses of single cells. There are five sub-projects to determine system properties and behaviour and three sub-projects to employ different and complementary modelling ...

Transcriptional and physiological responses of anaerobic steady state cultures to pulses of electron acceptors, specifically nitrate, trimethylamine-N-oxide (TMAO)

Changing the oxygen availability leads to an adaptation of Escherichia coli at different biological levels. After pertubation of oxygen in chemostat experiments the microorganism(s) will come back to another steady state. This investigation deals with these stationary responses of Escherichia coli within the aerobiosis scale. The change for different biological variables, in different areas of the organism like the electron transport chain, the TCA cycle or globally is investigated by wildtype ...

This experiment uses a low-copy plasmid based system (MG1655 Δlac FF(-41.5)/RW50) for measuring FNR activity. Initial acetate calibration of the chemostat with the MG1655 Δlac strain was carried out, with β-galactosidase activity from the FF(-41.5)/RW50 reporter plasmid measured at 100%, 80%, 50%, 20% and 0% aerobiosis levels. Finally, the aerobiosis levels were re-determined by calculating the actual acetate flux in the sampled chemostat runs.

Note: the strain used (MG1655 Δlac) is not the same ...

The model describes the behaviour of E. coli in a stationary chemostat with different oxygen availability.

The data that was published in Alexeeva et al. [1-3] and Alexeeva [4] is an important prerequisite for SUMO. It is used for the development of the models and for the comparison with the SUMO data. By means of the program EasyNPlot [5] the data in the important plots of [1-3] and of the plot of the ArcA activity in [4] was digitalized. The result can be found in the attached files.

[1] Svetlana Alexeeva, Bart de Kort, Gary Sawers, Klaas J. Hellingwerf, and M. Joost Teixeira de Mattos. Effects of ...

The abscissa of the plots shows the percentage of aerobiosis that is a physiological measure for oxygen availability (http://www.ncbi.nlm.nih.gov/pubmed/11844770).

1. Grey Boxes: Enzymes & Reactions blue lines/symbols: flux in mmol per gramm dry cell weight an hour red lines/symbols: mRNA levels

2. White Boxes: Intracellular and extracellular metabolites blue lines/symbols: concentration of the metabolites (extracellular: mM, intracellular: AU)

3. Yellow Boxes: Aggregated Quantities as yield, ...

The model describes the catabolism of Escherichia coli and its regulation. The metabolic reactions are modeled by the thermokinetic model formalism. The model is simplified by assuming rapid equilibrium of many reactions. Regulation is modeled by phenomenological laws describing the activation or repression of enzymes and genes in dependence of metabolic signals. The model is intended to describe the behavior of E. coli in a chemostat culture in depedence on the oxygen supply.

The model is described ...

This SOP defines the format of SOPs used in the SUMO consortium.

Presentation by Michael Ederer and Klaas Hellingwerf at the SysMO Conference 2013 (Feb 2013, Berlin)

Presentation by Robert Pool at the SysMO Conference (Feb 2013 in Berlin)