Press releases – December 2014

FRANKFURT.  The steering committee of the German Research Foundation last week in Bonn announced that the Frankfurt ancient historian Prof. Hartmut Leppin was awarded the 2015 Gottfried Wilhelm Leibniz Prize, which is endowed with a grant of 2.5 million Euro. Prof. Werner Müller-Esterl, President of Frankfurt University, congratulated the researcher who was selected along with seven other scholars. Müller-Esterl called the prize a "distinction for a scholar who has made significant contributions to profiling the historical studies at Goethe University through his research on ancient history. The prize is the 'icing on the cake' of the anniversary year at Goethe University." Leppin has become renowned internationally thanks to his diverse publications and his involvement in joint research projects with good international exposure. "Leppin is the fifth recipient of the Leibniz Prize at Goethe University since 2010 alone, underscoring the level of excellence in research at our university", Müller-Esterl is happy to say. "And it is already the fourth award to be won by the humanities and social sciences."

The 51-year-old historian has been with Goethe University as a professor of ancient history since 2001, declining reputable appointments in Hannover, Cologne and the Humboldt University in Berlin in its favour. His research centres around the history of political thought in Ancient Greece and the history of Christianity in antiquity. Many of his publications extend across the boundaries between antiquity and the Middle Ages. His research covers a period of 600 years – from the birth of Christ to the beginnings of Islam.

Leppin is extremely well connected in the humanities and social sciences, and also seeks dialogue with fellow historians. This is evidenced by his latest success in obtaining a grant from the DFG for the special research centre "Discourses on weaknesses and resource regimes", for which Leppin acts as speaker. Additionally, the ancient historian is involved in the Frankfurt Cluster of Excellence "The Formation of Normative Orders", as well as participating in the research training group on "theology as a science". Furthermore, he is a supporter of the Research Centre for Historical Humanities at Goethe University. The Volkswagen Foundation describes this centre as "original, innovative and exemplary" and is providing 820,000 Euro for the centre's work.

Leppin's monograph "Das Erbe der Antike" (The Legacy of Antiquity), published by C.H. Beck Verlag 2011, also highly appreciated by non-historians and drew a lot of attention. He clearly demonstrates that Europe as we know it today originated in the Mediterranean world of antiquity, and illustrates the history of antiquity based on three ideas: freedom, empire and true faith. He addresses important eras with these terms: "freedom" for Ancient Greece during the Attic democracy, "empire" for the Roman Empire, and finally the empire of late antiquity with "true faith".

Leppin is currently focusing most of his efforts in his research on "Christianisations in the Roman Empire". This work is being sponsored by the German Research Foundation with a 500,000 Euro grant over five years within the framework of a Koselleck project. While lots of work has been done on Hellenisation and Romanisation, little research has been done on Christianisation to date. The project is intended to close this gap through theoretical and empirical research into fundamental processes during the Imperial and Late Antiquity periods, which are important to the broader history within and beyond Europe. Christianisation occurred at varying times and degrees in different regions and fields, such as royal self-portrayal and the use of Christian symbols in art. This is why Leppin intentionally uses the term Christianisations in the title. Leppin's book "Antike Mythologie in christlichen Kontexten der Spätantike" (Ancient Mythology in the Christian Contexts of Late Antiquity) is due for publication by de Gruyter soon. This comprehensive project ties in well with Leppin's research in the excellence cluster "The Formation of Normative Orders". There he is researching imperial politics and religious spheres in the 3rd century. With the endowment from the Leibniz Prize, Leppin is planning to delve more deeply into the question of the degree to which the Christian Empire permitted or restricted religious and cultural diversity. The ancient historian is hoping to make inroads into research on early Islam and to help answer the question of the historical significance of the spread of three monotheistic religions.

Biography of the Leibniz Prize recipient: Leppin studied history, Latin, Greek and pedagogy at Marburg, Heidelberg, Pavia, and Rome. He completed his first state examination for teaching History and Latin in 1988, received his doctorate from Marburg in 1990 with a study on Roman stage artists, followed by a post-doc at the Free University of Berlin in 1995 with a study on the Greek church historians of the 5th century AD. He has been teaching at Goethe University since 2001. He is liaison professor of the  German National Academic Foundation and sits on the DFG review board. Leppin is also active as advisor and associate editor for various publications: Antike Welt, Centro Ricerche e Documentazione sull’antichità classica, Handwörterbuch der antiken Sklaverei, Historische Zeitschrift, Millennium, and Reallexikon für Antike und Christentum.

Hartmut Leppin is the 16th scientist at Goethe University to be awarded this prize. In 1986, the philosopher Jürgen Habermas and the later Nobel Prize winner and biochemist Hartmut Michel received the coveted prize. They were followed by historian Lothar Gall (1988), physicist Reinhard Stock (1989), legal historian Michael Stolleis (1991), mathematician Claus-Peter Schnorr (1993), physicist Theo Geisel (1994), chemist Christian Griesinger (1998), paleontologist Volker Mosbrugger (1999), biologist Stefanie Dimmeler (2005), historian Bernhard Jussen (2007), economist  Roman Inderst (2010), philosopher Rainer Forst (2012) biochemist Ivan Dikic (2013) and legal scholar Armin von Bogdandy (2014).

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FRANKFURT  Frankfurt physicists have once again contributed to resolving a disputed matter of theoretical physics. Science has long since known that, contrary to the old school of thought, helium forms molecules of two, three or even more atoms. Exactly what helium consisting of three atoms looks like, however, has been disputed by theoretical physicists for about 20 years. Besides the intuitive assumption that the three identical components form an equilateral triangle, there was also the hypothesis that the three atoms are arranged linearly, in other words in a row. As the group of scientists led by Prof. Dr. Reinhard Dörner and his graduate student Jörg Voigtsberger report in the current edition of the prestigious journal Nature Communications, using the COLTRIMS reaction microscope, they were able to demonstrate that the truth lies in between the two.

"Nature gets out of it quite elegantly here: We looked at the helium molecule” under our reaction microscope, and it was found that He₃ is like a cloud," says Voigtsberger, whose dissertation is the source of the publication results. "It makes no difference whether it's linear or triangular or another configuration: all are equally probable, as is typical for quantum mechanics." Moreover, Voigtsberger and his coworkers' results put an end to an idea carried over from school days: The He₃ molecule does not consist of a solid structure, as is the case, for example, with the hydrogen molecule H₂ and the carbon dioxide molecule CO₂, in which the individual atoms quasi impinge directly on one another. In contrast, He₃ is like a cloud – the distance between the atoms is roughly ten times the atomic radius.

Finally, Voigtsberger and Dörner report that one variant of the He₃ molecule behaves in an unusual way: normal helium atoms consist of two protons and two neutrons. If one of the three helium atoms is replaced by the lighter isotope, which consists only of two protons and one neutron, then the molecule will be in a so-called quantum halo state: the lighter isotope is further away from the other two atoms than should be possible according to classic physics. "One can visualise this as ping pong balls in a soup bowl," explains Dörner. "Normal atoms collect at the bottom of the bowl, at a minimum of the potential. If they overcome the potential mountain, in other words the wall of the bowl, they will be completely separated from the molecule. Thus the lighter helium isotope is, as it were, outside of the bowl but, due to the quantum mechanical tunnel effect, it still "notices" the atoms in the bowl and cannot simply fly away."

The COLTRIMS reaction microscope, with which the experiments on helium molecules were conducted, has already demonstrated its versatility many times: in 2013, Dörner's work group had already been able to resolve a dispute of theoretical physics. In that case, the COLTRIMS experiments proved that the position of the Danish physicist Niels Bohr in the "Einstein-Bohr debates" 80 years ago was correct and, shortly before that, other physicists from the atomic physics work group used COLTRIMS to "film" the destruction of a molecule by a strong laser pulse – a reaction so fast that it cannot be captured by an ordinary camera.

Publication: J. Voigtsberger et al., Imaging the structure of the trimer systems ⁴He₃ and ³He⁴He₂ in: Nature Communications, 5:5765, DOI: 10.1038/ncomms6765

Information: Prof. Dr. Reinhard Doerner, Institut für Kernphysik [Institute of Nuclear Physics], Campus Riedberg, Telephone (069) 798-47003, doerner@atom.uni-frankfurt.de

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A research team from Kiel University (CAU) and Goethe University Frankfurt has jointly created a synthetic surface on which the adhesion of E. coli bacteria can be controlled. The layer, which is only approximately four nanometres thick, imitates the saccharide coating (glycocalyx) of cells onto which the bacteria adhere such as during an infection. This docking process can be switched on and off using light. This means that the scientists have now made an important step towards understanding the relationship between sugar (carbohydrates) and bacterial infections. Their research results embellish the front page of the latest issue of the renowned journal Angewandte Chemie (Applied Chemistry).

The bond between either cells and other cells or cells and surfaces is vital to organisms, for example in the development of internal organs and tissue. However, these mechanisms are also involved in illness and infections. The E. coli bacteria used in the experiment can cause urinary tract infections, meningitis, sepsis and other severe illnesses. In order to understand and treat these illnesses, researchers need to decipher the molecular processes which allow the bacteria cells to dock onto the healthy host cells.

This often happens by way of proteins, which interact with carbohydrate structures on the surface of the host cell by means of a complex fit principle (simplified: lock-and-key principle). The Kiel/Frankfurt study demonstrates for the first time that the spatial orientation of the carbohydrate structures is crucial to this process. However, in natural glycocalyx, a mere nanometre thick polysaccharide layer covering all cells, the relationships are still too complex to uncover how proteins and carbohydrates identify each other.

In Collaborative Research Center (SFB) 677 'Function by Switching', Professor Thisbe K. Lindhorst, chemist at Kiel University, and her team construct molecules which, when irradiated by light at different wavelengths, operate as biological switches. Together with the working group around the surfaces specialist Professor Andreas Terfort (Frankfurt University), the Lindhorst group has now produced a system with which the orientation of the saccharide docking points, and thus the bonding of E. coli bacteria, can be controlled. To do this, the scientists covered an extremely thin gold surface with a precisely defined saccharide covering, coupled to azobenzene. This is a hydrocarbon containing a nitrogen bridge and operating as a hinge controlled by light. The bonding properties of the saccharide coating can now be switched using this method: if the researchers irradiate their system with light with a wavelength of 365 nanometres, considerably fewer pathogenic bacteria cells can adhere to the synthetic surface. The saccharide molecules turn away from the bacteria, in a sense, and can no longer be recognised. When switched on by 450 nanometre wavelength light waves, on the other hand, the structures reorientate such that the bacteria cells can dock on once again. In this way, E. coli adhesion can be controlled.

'By employing a layer system on a solid surface, in combination with a photo-hinge, the complex dynamics of a real glycocalyx can be reduced to the principal processes and thus be better understood', explains Terfort. 'It should be possible to transfer this novel approach to other biological boundary layer systems.'

'Based on our model system, glycocalyx recognition and bonding effects can be precisely defined and investigated from a completely new angle', says Lindhorst. 'If we can learn how to influence glycocalyx in the context of the relationship between health and healing, it will lead to a revolution in medicinal chemistry.'

Original publication

Switching of bacterial adhesion to a glycosylated surface by reversible reorientation of the carbohydrate ligand. Theresa Weber, Vijayanand Chandrasekaran, Insa Stamer, Mikkel B. Thygesen, Andreas Terfort and Thisbe K. Lindhorst. Angew. Chem. 48/2014 DOI: 10.1002/ange.201409808 and 10.1002/anie.201409808 (Angew. Chem. Int. Ed.) 

Photos and figures are available for download:
http://www.uni-kiel.de/download/pm/2014/2014-395-1.jpg

Caption: Left: E. coli bacteria can dock onto the saccharide molecules of the synthetic glcocalyx using the FimH protein. Right: When irradiated with light at a wavelength of 365 nanometres, the saccharide molecules on the surface bend away and cannot be recognised by the proteins. The bacteria can then no longer dock onto the host cell.
Figure/Copyright: Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

http://www.uni-kiel.de/download/pm/2014/2014-395-2.jpg
Caption: Controlled bonding: the adhesion of bacteria onto saccharide molecules on the glycocalyx model can be reversibly controlled by light.
Figure/Copyright: Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

http://www.uni-kiel.de/download/pm/2014/2014-395-3.jpg
Caption: Scanning electron micrograph of Escherichia coli, grown in culture and adhered to a cover slip.
Credit: NIAID

http://www.uni-kiel.de/download/pm/2014/2014-395-4.jpg
Caption: Thisbe K. Lindhorst (photo) and her team control the adhesion of E. coli bacteria using switchable saccharide molecules.
Photo/Copyright: Stefan Kolbe

http://www.uni-kiel.de/download/pm/2014/2014-395-5.jpg
Caption: Surfaces specialist Andreas Terfort (photo) from Goethe University Frankfurt
Photo/Copyright: Larissa Zherlitsyna 

Contact
Prof. Dr Thisbe K. Lindhorst
Christian-Albrechts-Universität zu Kiel
Otto Diels-Institut für Organische Chemie
Tel.: +49 (0)431 880-2023
E-mail: tklind@oc.uni-kiel.de 

Prof. Dr Andreas Terfort
Goethe-Universität Frankfurt
Tel.: +49 (0)69798-29180
E-mail: aterfort@chemie.uni-frankfurt.de

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