Projects
In order to be able to utilize plant feed, ruminants have a consortium of various microorganisms in their rumen, which break down cellulose-containing fibers and convert them to fatty acids in various fermentation processes. The formation of fatty acids and the newly formed microbial protein serve as essential food sources for the metabolism of the ruminant. Here, the bacterial genus Prevotella, which is particularly abundant in the rumen microbiome, is of particular importance. In this collaborative project, we will describe the degradation pathways for carbohydrates and proteins in Prevotella, investigating the extent to which the availability of essential trace metals such as iron and zinc influences the catabolism of Prevotella and thus the provision of nutrition to the cow. Using state-of-the-art microscopic techniques, we will also study the interaction of Prevotella with its surrounding extracellular polysaccharide (EPS) matrix, as the EPS matrix is thought to play an important role in the resilience of Prevotella to antimicrobial agents such as monensin. In a cross-scale approach, we will study single molecules (enzymes and transporters), Prevotella cells from pure culture, and microbial consortia. The goal is a comprehensive understanding of the metabolic performance of Prevotella under varying metal availability, or in the presence of the antibiotic monensin, with respect to cow nutrition.
Segatella copri is a key member of the human gut microbiome and its strain-level diversity is well described in several studies indicating different metabolic capabilities and positive effects on the host. The species is described to be a possible next-generation probiotic. This would require either nutritional strategies to stimulate the establishment of S. copri in the gastrointestinal tract, or additional supplementation as actively growing culture. The latter requires that these strictly anaerobic bacteria exhibit some oxygen resilience, since during the application, oxygen exposure cannot be excluded. Also, during passage through the gastrointestinal tract, S. copri will be exposed to varying oxygen concentrations. There is still a lack of knowledge on how S. copri is able to cope with even small oxygen concentrations and which enzymes are involved to counteract oxidative cell damage. The genome of S. copri contains genes for a terminal oxidase and a peroxidase, but no genes for superoxide dismutases or catalases are annotated. We hypothesize that S. copri (1) reduces the O2 concentration with the help of a terminal oxidase in respiratory process (“nanaerobic respiration”), and (2) possesses an antioxidant defense mechanism where peroxides are reduced by a thioredoxin-dependent peroxidase. In our collaborative project in the context of the SPP2474 (lluminating gene functions in the human gut microbiome), we aim at identifying the genetic repertoire and the enzymatic reactions acting against oxidative stress. To understand oxygen resilience at all biological levels, we will compare the transcriptome, proteome and metabolome of selected S. copri strains cultivated with or without oxidative stress. The findings will be approved by mutant strains lacking ROS-protective components and enzymes. Understanding these mechanisms will be crucial to enhance the survival of S. copri during future applications as a probiotic strain. This can prevent possible selection mechanisms during oxygen exposure in the gastrointestinal tract which might lead to negative effects on the host.
This collaborative project is supported within the DFG Collaborative Research Centre 1450 (insight-Multiscale imaging of organ-specific inflammation). Activated monocytes and granulocytes are key to inflammatory diseases and release the alarmin S100A8/A9 in high concentrations. We will establish a specific S100A8/A9 tracer combining X-ray structure analysis and chemical synthesis.
Principal investigators: Günter Fritz, Andreas Faust
https://www.uni-muenster.de/CRC-inSight/
Completed projects
Interplay of immune cells and bacteria in response to stimulation by stress hormones in pigs
In this collaborative project supported by the DFG, we study the mechanisms by which pathogenic bacteria modulate the effect of stress hormones in pigs.
Principal investigators: Volker Stefanski, Julia Fritz-Steuber
http://gepris.dfg.de/gepris/projekt/272280174
Analysis of properties and assembly of the intramembrane FeS cluster in Na+ -NQR and RNF complexes
This collaborative project is supported within the DFG SPP 1927 (iron-sulfur for life). Our goal is to understand how an unprecedented FeS center is incorporated into a respiratory enzyme found in many bacteria.
Principal investigators: Günter Fritz, Julia Fritz-Steuber
Interplay between fermentative and respiratory energy conservation in Prevotella sp.
In this collaborative project supported by the DFG, we address the metabolism and physiology of an important bacterium of the rumen.
Principal investigators: Jana Seifert, Julia Fritz-Steuber
http://gepris.dfg.de/gepris/projekt/327953272
LAPIN: Inhibitors targeting the respiratory Na+ pump of gram-negative microorganisms
We are searching for inhibitors against gram-negative pathogenic bacteria.
This collaborative research project (2018-A33) is funded by the Else Kröner-Fresenius Stiftung.
Principal investigators: Julia Fritz-Steuber, Günter Fritz