Using metabolomics to search for new natural products in moss
Jethro Hemmann talks about his new independent junior research group “Metabolomics-guided Natural Product Discovery”
| by Friederike Gawlik
When Jethro Hemmann took over as head of the newly founded Thuringian junior research group “Metabolomics-guided Natural Product Discovery” at the Leibniz-HKI in January 2025, it was clear to him from the outset that the coming years would be exciting. For the young scientist, this opportunity also comes with some challenges. How is he coping? “Very well so far. There are a lot of new things coming my way, but it’s fun to familiarize myself with them and to take on the new activities and responsibilities,” he says.
A new research topic, his own team and the freedom to realize a scientific vision – for Hemmann, this is the next big step in a career that has taken him from Zurich to Jena and to the head of his own research group.
From studies in Zurich to research in Jena
Even during his studies at ETH Zurich, Hemmann was fascinated by the smallest compounds in the world: molecules. “I was interested in biochemistry early on, in the chemical basis of living organisms. It is fascinating to see which molecules play a role, especially in bacteria.” This enthusiasm eventually led Hemmann to do his doctorate at ETH, where he studied bacteria and their metabolism.
After his dissertation, he moved to Jena as a postdoc at the Leibniz-HKI, where he worked on a scholarship in the former junior research group “Synthetic Microbiology” under the direction of Gerald Lackner. Here, Hemmann deepened his knowledge of natural product research and specialized in metabolomics – an analytical method that uses mass spectrometry to record the totality of all molecules in cells or entire organisms. “Mass spectrometry has always fascinated me and I would now like to use it with my group for research on mosses.”
Mosses as nature’s survival artists
But why mosses in particular? In the world of plants, they are often overshadowed by the higher flowering plants. Yet they are true survival artists. There are 16,000 to 20,000 species worldwide. “Mosses are often ignored and do not receive the same attention as higher plants because they are relatively simple. But they were the very first land plants and interacted with microbes hundreds of millions of years ago.” Mosses grow even under extreme conditions, defying both drought and humidity. From tropical rainforests and bare deserts to arctic tundra, they are found in all ecosystems. Scientists suspect that the microorganisms living on the moss make a decisive contribution to this resilience.
“We hope that we will find new natural products that may be relevant for the protection of mosses – for example against fungi or damp environments.” The idea: if mosses and their microbes use chemical substances to defend themselves against pathogens or environmental stress, then these molecules could also be of interest to us, for example as the basis for new antibiotics or antifungals.
But where do the mosses for research come from? “On the one hand, there is a collection of strains from which we can obtain them in a controlled manner. But of course, we also want to collect mosses directly from nature in order to isolate their bacteria and cultivate them in the laboratory.” In Jena, the Haussknecht herbarium at the new Senckenberg Institute for Plant Diversity also has outstanding expertise in the field of mosses – a stroke of luck for the new research group.
Metabolomics – a look into the chemical language of life
At the heart of Jethro Hemmann’s and his team’s research is metabolomics, an area of research that deals with the comprehensive analysis of metabolites in biological samples.
“In metabolomics, we try to examine the metabolites, i.e. the molecules that are present in cells or are secreted by them, in their entirety,” says Hemmann, explaining the method. Metabolites play a central role in the metabolism of cells and organisms. Of particular interest to Hemmann are secondary metabolites – molecules that are of great importance for the communication and defense of microorganisms due to their chemical diversity and activity. “Metabolomics does not focus on individual substances, but measures many together.” This is where mass spectrometry comes into play – a high-tech method that can identify molecules in minute quantities based on their weight. This makes it possible to detect new natural products and analyze their structures.
The young researchers from Jena are particularly interested in the so-called RiPPs (Ribosomally synthesized and Post-translationally modified Peptides), a group of natural products that has not yet been studied very much. “I already worked intensively with these peptides during my postdoc phase. It is a very diverse, large family that is currently coming more and more into the focus of natural product research. It would be exciting if we could find new RiPPs in the moss microbiome.”
Natural products as potential remedies
However, the research goes beyond simply discovering new molecules. The young group also wants to understand the role of natural products in their natural context. “We are interested in the interaction between bacteria and mosses. What role do natural products play in the ecosystem? Are they signal molecules, do they serve defense or communication?”
These questions are not only relevant for basic research. They could also have practical applications. “One aim is to identify natural products that are effective against bacteria or fungi and, in the best case, have the potential to be developed into antibiotics or antifungals.” Initial studies show that moss-associated microbes do indeed frequently produce bioactive compounds.
The most important thing is the people
Of course, a project like this cannot be tackled single-handedly. Building a functioning, motivated working group is Hemmann’s top priority at the moment. “The most important thing now is to build a good team that is enthusiastic and dedicated to the scientific questions together.” Hemmann jokingly adds: “The human interactions are just as important as the microbial ones.”
The funding from the Free State of Thuringia with resources from the European Social Fund Plus was crucial to the establishment of the research group. Without this support, the project would not have existed in this form. But now the course has been set.
The junior research group fits perfectly into the research environment at the Leibniz-HKI. “The metabolomics methods that we are developing can be used in many areas. There are already close links with groups at the Leibniz-HKI that deal with natural products, for example with Christian Hertweck or Luzia Gyr.” Collaborations with the Bio Pilot Plant and the newly founded department Deep Microbiome Metabolomics promise further exciting synergies.
Looking to the future – more than just mosses?
Even though the moss microbiome is currently the focus of Jethro Hemmann’s research – he is thinking long-term. “I deliberately wanted to broaden the topic of the junior research group. Metabolomics can be applied to different microbiomes. Perhaps we will also investigate other ecological niches or organisms in the future.”
But until then, the scientists in Hemmann’s group want to devote a lot of time to mosses. And who knows? Perhaps the next big breakthrough in natural product research is hidden in an inconspicuous moss cushion on the Thuringian forest floor.
