Cell-cell-signaling and its influence on natural microbial communities of pyrite-oxidizing acidophiles

• Applicant: Dr. Sören Bellenberg
• Subject Area: Microbial Ecology and Applied Microbiology ; Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2018 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 402385999

Common microbial communities are complex, multivariate systems that can consist of many different species that interact with each other, communicate, and respond individually to various environmental influences. In particular, the importance of biological interactions of microorganisms by means of cell-cell communication and its influence on the formation and modification of natural and biotechnically relevant microbial consortia is hardly understood. Within the scope of this research project, the influence of biochemical cell-cell communication on microbial consortia in a model ecosystem will be investigated. The acid mine drainage ecosystem is particularly suitable for this purpose as it has lower biological diversity than most pH neutral ecosystems. Microbial consortia of the bioremediation-relevant acid mine drainage (AMD) ecosystem can lead to massive environmental damage, and can be used biotechnologically in industrial bioleaching for the production of copper and gold from low-grade ores. Although presence of acyl-homoserine lactone mediated quorum sensing pathways in the genome of the model species Acidithiobacillus ferrooxidans and its implications on molecular signaling and interspecies interactions have been demonstrated, preliminary analyses demonstrated the presence of further cell-cell communication pathways in further isolated bacteria from these ecosystems. Furthermore, the extent to which all these pathways play a role in the natural environment remains unknown. Naturally occurring signal molecules will be analyzed in their concentration in laboratory mock communities and environmental samples. The development of microbial communities will be elucidated using 16S rRNA tag sequencing and the microbial metabolic activity is investigated by gene expression using metatranscriptomics. Influence of cell-cell signaling and the manipulability of the microbial ecosystems will be demonstrated by the addition of selected signaling molecules to AMD mock communities, which will be cultivated in the laboratory and monitored using the methods mentioned above. I anticipate that concentration profiles of QS signal compounds can be related to general trends in the development of microbial community compositions and that this development can be manipulated by addition of specific signal compounds. The results from the planned investigations will open new gates by extrapolation to more complex ecosystems and will thus be the basis for new research hypotheses and discoveries. As well, the development of methods for the targeted manipulation of consortia in the environment and in medical or biotechnological applications could be fostered with an improved understanding of cell-cell communication effects in microbial communities.

• DFG Programme: Research Fellowships
• International Connection: Sweden
• Host: Professor Dr. Mark Dopson