Martin Ackermann, Ph.D.

PriME Project:

Together with colleagues on the PriME project, Martin Ackerman and his group aim to better understand how the collective metabolism observed at the level of microbial communities emerges from the activities of individual members and from interactions between them. A second focus of their PriME project centers mostly on the factors that shape metabolic interactions between two different microbial species, and on the cellular decision-making of individual microbes that experience spatial and temporal gradients in nutrient concentrations.

In a first step, the group will analyze metabolic interactions affected by the death of microbial cells. Many metabolic interactions are based on the exchange of metabolites that are passively released from microbial cells and then taken up by others. The release of metabolites can be strongly increased by cell death, upon which cellular components diffuse freely. Cell death can be induced by neighboring cells through specialized molecular syringes that deliver toxins into a target cell. The group will investigate whether this killing mechanism can serve as a foraging mechanism for marine microbes that colonize particles. To do so, they will combine quantitative single-cell measurements with mathematical modeling and the analysis of natural samples to critically test this hypothesis.

In a second step, the group aims to derive principles of how metabolic activities are spatially distributed in microbial communities that colonize the surface of marine particles. To understand and predict the collective activity in such communities, they need to understand how community members arrange in space, and how the spatial arrangement determines metabolic linkage and thus community growth. The group will capitalize on a microfluidic approach that they have established during the first part of the PriME project and on methods to quantify the uptake and assimilation of nutrients at the level of single cells. The goal of this second step is to derive principles of the spatial self-organization of microbes and metabolic processes and how this self-organization determines community-level functions.

In a third step, the group will scale up and ask how microbial metabolism unfolds in response to gradients at larger scales. More specifically, they aim to understand metabolic strategies of microbes in situations where the availability of nutrients changes over time and space. They will first analyze how flexible microbes are in the composition of their biomass. If they experience an environment where some nutrients are in excess, do they take up the nutrients and thereby change their elemental composition? The degree of short- and longer-term plasticity in elemental composition is currently not well understood yet is central for biogeochemical models of the ocean. Then, together with the group’s collaborators, they will synthesize these experimental observations into a mechanistic model of microbial growth that are informed by the spatial and temporal scales of nutrient fluctuations that are typical for the ocean.

Bio:
Martin Ackermann is a professor of microbial systems ecology at ETH Zürich and is also associated with Eawag, the Swiss Federal Institute of Aquatic Science and Technology. He studied biology at the University of Basel, majoring in evolutionary biology. He completed a Ph.D. at Basel on aging processes in bacteria. After completing postdoctoral training at the University of California, San Diego, he joined ETH Zürich in 2004, where he started his own group in 2006.

Ackermann’s group consists of about 15 Ph.D. students and postdoctoral researchers with backgrounds in microbiology, evolutionary biology, physics and computer science. The goal of the group is to work on general principles of how bacteria interact with each other and with their environment, and on how new functionality at the level of microbial consortia emerges based on the properties of individuals and their interactions. To address these questions, the group uses a quantitative-biology approach to microbial ecology; it performs quantitative single-cell measurements to determine processes at the level of individual cells, analyzes how individual cells interact among each other, and then scales up to understand processes in populations and communities. The group’s current main research interests include collective polymer degradation in bacterial populations, the spatial distribution of metabolic processes in microbial populations and communities, and the evolutionary dynamics of metabolic interactions in spatially structured communities.