• “Cross-Kingdom Interactions Shaping Microbial Spatial Organization” by Dr. Chujin Ruan

  Date:  January 22, 2025, 10:00 am           

Abstract: During surface-associated expansion, microbial communities develop intricate spatial patterns shaped by natural selection, ecological drift, and dispersal dynamics. My research try to understand cross-kingdom interactions in microbial spatial organization, with a focus on phage-bacteria and fungal-bacteria interactions. Regarding phage-bacteria dynamics, our findings challenge the prevailing assumption that phage predation does not significantly influence the dissemination of antibiotic resistance. We demonstrate that phage predation reduces spatial segregation between plasmid donors and recipients carrying antibiotic resistance genes, thereby enhancing bacterial intermixing and facilitating plasmid transfer. This process may inadvertently accelerate the spread of resistance during phage therapy. In fungal-bacteria interactions, fungal hyphae function as dispersal networks, enabling bacteria located behind the expansion front to redistribute and mitigate diversity loss. Experiments using bacterial strains on hyphal networks revealed that fungal-assisted dispersal, particularly through flagellar motility, promoted spatial intermixing and enhanced plasmid transfer of antibiotic resistance genes. Taken together, these findings highlight the ecological implications of cross-kingdom interactions: while phage- and fungal-driven community reorganization can exacerbate the spread of antibiotic resistance, it can also contribute to the maintenance of microbial diversity and influence evolutionary trajectories. This work advances our understanding of microbial ecosystem dynamics and highlights critical considerations for managing ecological stability and antibiotic resistance.

• “Steps Towards the De-Novo Synthesis of Life”  by  Prof. Dr. Sijbren Otto

  Date:  October 4 2023, 1:00 pm          

Abstract: How the immense complexity of living organisms has arisen is one of the most intriguing questions in contemporary science. We have started to explore experimentally how organization and function can emerge from complex molecular networks in aqueous solution.  We focus on networks of molecules that can interconvert, to give mixtures that can change their composition in response to external or internal stimuli. Noncovalent interactions within molecules in such mixtures can lead to the formation of foldamers. In contrast, molecular recognition between molecules in such mixtures leads to their mutual stabilization, which drives the synthesis of more of the privileged structures . As the assembly process drives the synthesis of the very molecules that assemble, the resulting materials can be considered to be self-synthesizing. Intriguingly, in this process the assembling molecules are replicating themselves, where replication is driven by self-recognition of these molecules in the dynamic network. The selection rules that dictate which (if any) replicator will emerge from such networks are starting to become clear.

 

We have also witnessed spontaneous differentiation (a process akin to speciation as it occurs in biology) in a system made from a mixture of two building blocks. When such systems are operated under far from-equilibrium flow conditions, adaptation of the replicators to a changing environment can occur.  Replicators that are able to catalyse reactions other than their own formation have also been obtained, representing a first step towards metabolism. Thus, the prospect of Darwinian evolution of purely synthetic molecules is tantalizingly close and the prospect of synthesizing life de-novo is becoming increasingly realistic.