The economist studied and earned his doctorate at the University of Mannheim, then conducted research in Munich and at the University of California, Berkeley. In 2009, he took up a professorship at the University of Mainz before moving to Gelsenkirchen in 2012, where he has held the professorship for Statistics and Econometrics ever since. His research focuses on methodological and applied issues in econometrics and empirical economic research.

For the past four years, the European Economic Association has been honouring teachers who contribute to the dissemination of economic knowledge through exceptional commitment and innovative approaches with the Award for Exceptional Teaching in three categories. The prize money is 1,000 euros. 

Sharks are known for being able to replace their teeth, with new ones growing to replace older ones when they wear down. This is crucial for their survival as they rely on their teeth to catch their prey. 

A research team headed by Professor Dr Sebastian Fraune from the Institute of Zoology and Organismic Interactions at MUHS has, in collaboration with biologists from the Sealife Oberhausen marine aquarium, examined the impact of ocean acidification on shark teeth. They placed shark teeth in containers of water at different levels of acidity: at the current pH of the oceans and at the expected pH in 2300. 

“Shark teeth comprise highly mineralised phosphates, but they are susceptible to corrosion. The more acidic water in the simulated 2300 scenario damaged the shark teeth, including roots and crowns, much more than the water at the current acidity level. Global changes are thus so far-reaching that they can impact the microstructure of shark teeth,” says Maximilian Baum, former MUHS student and now a freelance diver, photographer and speaker. He is the lead author of the study. 

Corresponding author Professor Fraune: “The teeth are highly sophisticated weapons designed to cut flesh, but not to withstand the acidification of the oceans. Our results show how fragile even nature’s sharpest weapons can be. It is possible that the ability of sharks to replace their teeth on an ongoing basis will not be able to keep up with the changes in their environment.” 

Teeth shed naturally by blacktip reef sharks (Carcharhinus melanopterus) kept at Sealife Oberhausen were used for the study. These teeth were divided between separate containers – one holding seawater with a pH of 8.1 (the current level) and the other with a pH of 7.3 (what is expected in 2300) – and incubated for eight weeks. Baum: “This pH corresponds to an almost tenfold increase in acidity compared with today.”

The teeth were then examined under the microscope at the Center for Advanced Imaging at MUHS. Fraune: “At a pH-value of 7.3, we observed surface damage such as cracks and holes, increased root corrosion and structural deterioration. In addition, the surface morphology was more irregular, which can weaken the structure of the teeth and make them more susceptible to breaking.”

Timo Haussecker, Aquarium Curator at Sealife Oberhausen and co-author of the study: “As we only examined naturally shed teeth, the study does not take account of any repair processes, which may occur in living organisms. The situation may therefore be more complex in living sharks as they may be able to remineralise damaged teeth, albeit with greater energy expenditure.” 

“Even moderate decreases in pH-values can impact more sensitive species with slow tooth replacement cycles or have a cumulative effect over the course of time,” adds Baum. “For sharks, it is certainly of great importance that the pH-value of the oceans remains near the current average of 8.1.”

Maximilian Baum and Professor Fraune conclude: “Our research reminds us that anthropogenic changes can impact entire food webs and ecosystems.”

Original publication

Baum M., Haussecker T., Walenciak O., Köhler S., Bridges CR. and Fraune S.. Simulated ocean acidification affects shark tooth morphology. Front. Mar. Sci. 12: 1597592 (2025). 

DOI: 10.3389/fmars.2025.1597592

However, plants do not produce the amino acids in all areas. Nine of these molecules, including important building blocks such as lysine and arginine, are only produced in the plastids. “Chloroplasts”, in which photosynthesis takes place, are also plastids. Until now, it was unknown how the amino acids are transported from the plastids to other parts of the plant. 

The research group headed by Professor Dr Andreas P. M. Weber from the Institute of Plant Biochemistry at MUHS has now attributed the function of transporting amino acids through chloroplast membranes to a class of transport proteins called RETICULATA1 (for short: RE1). This enables them to be exchanged within the plant.

Professor Weber, corresponding author of the study, which has now appeared in Nature Plants: “The molecular function of RE1 has been a mystery for decades, even though it was known that mutations in this gene cause conspicuous leaf shapes in the model plant Arabidopsis thaliana (thale cress). We now show that RE1 is a specialised transporter for basic amino acids such as arginine, citrulline, ornithine and lysine.”

Plants lacking RE1 not only have a characteristic “reticulated” leaf shape, but also only contain small amounts of basic amino acids in their leaves and chloroplasts. Lead author Dr Franziska Kuhnert: “This indicates a disrupted amino acid distribution in the plant. A complete loss of RE1 and its closest relative RER1 (RETICULATA-RELATED1) is even lethal to the plant, underscoring the essential role of these proteins.”

The research team was also able to demonstrate that the loss of RE1 reduces the biosynthesis of basic amino acids and impairs the balance of amino acid pools between plastids and cytosol – the fluid within the cells.

Kuhnert: “RE1 and related proteins are found exclusively in organisms that contain plastids. Since all plants and photosynthetic algae possess RE proteins, these proteins must be old in evolutionary terms and have originated from an era when plastids were formed through ‘endosymbiosis’ – the absorption of previously independent cells into other cells. RE1 may have made an important contribution to this evolutionary development of plants.”

“Our results provide crucial insights into the complex connection between the transport of amino acids into plastids and leaf development, as well as nutrient distribution in plants,” summarises Weber, adding: “The discovery opens up new perspectives for plant breeding and enables the development of crops with a higher content of essential amino acids. This can contribute to global food security.”

The research work was carried out at MUHS within the framework of the CEPLAS Cluster of Excellence and the collaborative research centres CRC1208/2 and 1535/1. All projects received funding from the German Research Foundation (DFG). In addition, co-author Dr Peter K. Lundquist received an Alexander von Humboldt Postdoctoral Fellowship.

Original publication

Franziska Kuhnert, Philipp Westhoff, Vanessa Valencia, Stephan Krüger, Karolina Vogel, Peter K. Lundquist, Christian Rosar, Tatjana Goss, and Andreas P. M. Weber. RETICULATA1 is a Plastid-Localized Basic Amino Acid Transporter. Nature Plants (2025). 

DOI: 10.1038/s41477-025-02080-z

In order to investigate the cellular and molecular factors that play a role in the development and severity of endometriosis, multidisciplinary experts from UCSF and Stanford University are conducting analyses of data from hundreds of women as part of the ENACT Center, led by Professors Drs Linda C. Giudice and Marina Sirota (UCSF) and Brice Gaudilliere and David K. Stevenson (Stanford). A team headed by UCSF Associate Professor Dr Tomiko T. Oskotsky is leading efforts to ensure robust experimental design for investigations involving high-throughput technologies, including single-nucleus RNA-sequencing. 

The samples have to be processed in batches for technical reasons. If these batches are not carefully balanced – e.g. with regard to disease stage or age of the patients – so-called batch effects can distort the results and ultimately make it difficult to judge whether observed differences have a biological cause or are simply artefacts from the technical process. 

This is where the anticlustering method comes in, which Dr Martin Papenberg from the Department of Experimental Psychology and Professor Dr Gunnar Klau, holder of the Chair of Algorithmic Bioinformatics – both from MUHS – presented in the journal Psychological Methods in 2020 (press release, German only). The researchers have made the “anticlust” module available free of charge. 

“Addressing the technical needs of the ENACT team requires, in addition to the previous scope of anticlust, that related samples – such as multiple tissue samples from the same patient – are grouped in the same batch to enable meaningful comparisons to be drawn for individual patients,” says Dr Papenberg, explaining the new challenge, which he was able to solve by developing the so-called “Must-Link Method”. 

Professor Klau: “We were able to expand our approach successfully to enable samples that need to remain together to be sorted into one batch, while maintaining a good balance of samples across different batches. This prevents methodological bias and medical colleagues can draw conclusions from the data, which relate specifically to the influences of the genes on endometriosis.”

Professor Oskotsky: “By using anticlust to minimise batch effects through better experimental design, we are confident that the findings in our molecular data genuinely reflect the underlying biology. This approach contributes to gaining new insights into endometriosis and demonstrates how well thought-out computational methods can significantly improve biomedical research.”

The research work was supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development, one of the National Institutes of Health of the USA, grant ID P01HD106414. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Original publication

Martin Papenberg, Cheng Wang, Maïgane Diop, Syed Hassan Bukhari, Boris Oskotsky, Brittany R. Davidson, Kim Chi Vo, Binya Liu, Juan C. Irwin, Alexis Combes, Brice Gaudilliere, Jingjing Li, David K. Stevenson, Gunnar W. Klau, Linda C. Giudice, Marina Sirota, Tomiko T. Oskotsky. Anticlustering for Sample Allocation To Minimize Batch Effects. Cell Reports Methods (2025). 

DOI: 10.1016/j.crmeth.2025.101137

A research team headed by Dr Thomas Hartwig and Dr Julia Engelhorn from the Institute for Molecular Physiology at MUHS and MPIPZ now presents a new, efficient method for mapping the genetic “switches” of plants in a current publication in Nature Genetics. Not actually genes themselves, these small sections of the genome determine when, where and to what extent a gene is active. They are comparable with a dimmer switch regulating the brightness of a lamp.

While research so far largely focused on the genes themselves, the new study demonstrates that key differences between plants – e.g. variation in size, or resistance to diseases or stress situations – are often not determined by the genes, but rather by these regulatory switches. Traditionally, however, it is not only difficult to locate these regions precisely, but also to determine which changes play the decisive role. This is now changing thanks to a new, scalable mapping method developed within the framework of the project. 

The research team analysed 25 different maize hybrids, i.e. crossbreeds of different maize varieties, identifying over 200,000 regions in the genome where natural variations influence regulatory switches. 

Dr Julia Engelhorn, lead author of the study: “Although these regulatory switches make up less than 1% of the genome, the variations often explain a substantial share of heritable trait differences – sometimes exceeding half.”

Dr Thomas Hartwig, corresponding author of the study, comments: “Understanding how these regulatory switches operate provides a powerful new tool to enhance both crop resilience and yield – laying the foundation for smarter breeding processes in the future.”

The researchers applied their method specifically to traits, which play a role in drought stress, identifying over 3,500 individual regulatory switches and the associated genes via which the plants respond to water-limited conditions. 

Engelhorn: “Our approach allows direct comparison of the differences in switch variants inherited via the maternal and paternal lines in a single experiment. We can thus offer the maize research community a resource of over 3,500 drought-linked regulatory sites – opening up new possibilities to fine-tune gene expression for enhanced robustness.”

Hartwig: “The precision of this mapping enables us to learn from the natural differences in the switches how they work, which in turn enables targeted manipulation of the switches to develop plants with improved traits.”

This research was realised in collaboration with a team from the University of California in Davis, in which Dr Samantha Snodgrass is a member. The co-author of the study emphasises the change in perspective accompanying the approach: “Despite decades of successful research, much of the genome – the parts outside the genes – remains a black box. This new method pulls back the curtain and enables us to identify the function of these non-coding areas, providing biologists and breeders with new, precise targets for new research and development approaches.”

The study was conducted within the CEPLAS Cluster of Excellence on Plant Sciences at MUHS and MPIPZ. Other sources of funding include the European Horizon Europe project BOOSTER, which aims to advance the development of climate-resilient cereal crops.

Original publication

Engelhorn, J., Snodgrass, SJ., Kok, A., Seetharam, A.S., Schneider, M., Kiwit, T., Singh, A., Banf, M., Khaipho-Burch, M., Runcie, D.E., Camargo, V.S., Torres-Rodriguez, J.V., Sun, G., Stam, M., Fiorani, F., Schnable, J.C., Bass, H.W., Hufford, M.B., Stich, B., Frommer, W.B., Ross-Ibarra, J., Hartwig, T. (2025). Genetic variation at transcription factor binding sites largely explains phenotypic heritability in maize. Nature Genetics (2025)

DOI: 10.1038/s41588-025-02246-7