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 Welcome to the Kümmerli lab 
Bacteria exhibit a wide range of social behaviours, including cell-to-cell communication, the formation of multicellular biofilms and fruiting bodies, and the secretion and sharing of beneficial metabolites. We are particularly interested in secreted metabolites, such as iron-scavening siderophores and enzymes, which can be shared as public goods between cells. We aim to understand this form of bacterial cooperation at multiple levels using Pseudomonas bacteria as our model system. 
(1) We examine how cooperation can evolve and be maintained over time. This is a non-trivial problem because any form of cooperation can be undermined by cheaters that still benefit from the cooperative acts performed by others, but no longer contribute to the cooperative efforts themselves. We further explore the complexity of social organisation within clonal groups, and ask how bacteria can reach accurate group-level decisions, and whether the possibility for division of labour exists.
 
(2) Public goods are often important virulence factors for opportunistic bacterial pathogens during the infection process. In this context, we aim to understand whether social interactions and cheating can also occur within hosts, and how such interactions affect virulence. Moreover, we study so-called ‘anti-virulence’ approaches, consisting in treatments disabling secreted virulence factors. Such treatments should render infections less harmful, and at the same time reduce selection for resistance.
 
(3) We investigate social interactions in more complex multi-species communities. This of interest because bacterial communities are typically diverse, and we have limited knowledge on how interactions between species affect community dynamics and stability. In this context, we work with both diverse communities from natural settings and artificially assembled laboratory communities.
Our research is funded by the Swiss National Science Foundation, the ERC, and several funding schemes of the University of Zurich