Redox Phenomena in Photosynthetic Bacteria - Applications in Systems Biology and Biotechnology

The project aims in establishing the facultative photosynthetic bacterium Rhodospirillum rubrum as a novel model organism for studying redox metabolism, redox signaling and control of gene expression in a Systems Biology approach of experimental techniques and mathematical modeling. Furthermore, the potential of the organism for different biotechnological applications will be explored and optimized. R. rubrum offers unique experimental possibilities for the purpose due to the formation of pigmented intracytoplasmic membranes (ICM) which contain the photosynthetic apparatus (reaction center and light-harvesting complexes) and which provide an easily accessible phenotypic marker for the redox-dependent activation of photosynthesic genes. The biosynthesis of ICM is controlled in a complex way with oxygen and light intensity as major environmental stimuli. Current hypotheses assign a central role for redox levels of electron transport chain (ETC) components in signal transduction. The observation that under semi-aerobic conditions, growth in the presence of both fructose and succinate (M2SF medium) yields ICM levels in the dark which are comparable to those observed under phototrophic growth at low light intensities presents an interesting tool for the elucidation of the molecular signals which control ICM induction and raises the question of how the different stimuli affect the redox state of ETC's. More Information about the R. rubrum Systems Biology project is available here.

Experiments of the group include:

  • biochemical and physiological characterization of bioreactor cultures
  • Quantitative determination of extracellular and intracellular metabolites
  • in vivo spectroscopical detection of cellular redox dynamics

    • Modeling includes:
  • stationary models (Metabolic Flux Analysis)
  • dynamic models (electron transfer chain)
  • process models
  • cybernetic models

    • with different levels of complexity.
    The group is embedded in the Systems Biologyactivities of the Max-Planck-Institute for Dynamics of Complex Technical Systems in Magdeburg and closely collaborating with the Bioenergetics group at Stuttgart University. Current research focuses on the role of cellular quinones as metabolic signals for gene regulation, interactions of quinones and cellular thiols, and interactions of central metabolic pathways and membrane-located signaling systems. The research group is basically experimentally oriented, but closely collaborating with theoretical groups. The mutual stimulation of experimental and theoretical methods which both are established at the MPI in Magdeburg offers the opportunity for getting novel insights and a systems level understanding of redox signaling and control in photosynthetic bacteria.