SPP 2389: Verständnis und Steuerung der zellulären Spezialisierung in leitfähigen multizellulären Strukturen

Conductive biofilms are produced by organisms that flourish in nature using insoluble electron acceptors, such as ferric or manganese oxides, as terminal electron acceptors of their respiratory chain. This conductivity allows cells that are not in direct contact with the electron acceptor to transfer respiratory electrons to neighbouring. The redox potential gradient then guides the electron flow through the matrix towards the point of highest redox potential, which is typically the mineral. Cells within these materials undergo specialization potentially due to: (I) thickness and cell density of the biofilm leading to cell-cell signalling as well as mass transfer limitation of the electron donor from the bulk phase, (II) respiratory electron transfer operating with different kinetics due to increasing resistance with electron transport length, (III) gradients forming, as in the case of pH, leading to growth with different kinetics and (IV) shear force leading to biofilm compression but also necessitating the formation of a stronger extracellular matrix. Currently, it's not understood how these factors influence the development of different regulatory routines that drive cellular specialization. Nevertheless, at a more phenomenological level, we observe these routines as cells construct different conductive structures based on their proximity to the terminal electron acceptor. We also observe that some layers in these conductive biofilms are primarily composed of non-living cells, yet these layers still function as conductive structures. Our goal is to decipher the triggers and regulatory mechanisms within individual cells that lead to the formation of these stable, dynamic conductive biofilm structures. A fundamental understanding of these processes will significantly impact how we perceive these structures in ecosystems, where they can have critically important functions. To reach our goal we will use multiparallel microfluidic bioelectrochemical experiments conducted with reporter strains and will use FACS coupled to transcriptomic analyses to understand regulatory routines. Moreover, we will aim to understand how these conductive biofilms interact conductively with other cells enabling new physiological features.

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