Press releases – September 2017

FRANKFURT. Gravity waves form in the atmosphere as a result of destabilizing processes, for example at weather fronts, during storms or when air masses stroke over mountain ranges. They can occasionally be seen in the sky as bands of cloud. For weather forecast and climate models, however, they are mostly “invisible” due to their short wavelength. The effects of gravity waves can only be taken into consideration by including additional special components in the models. The “MS-GWaves” research unit funded by the German Research Foundation and led by Goethe University Frankfurt has meanwhile further developed such parameterizations and will test them in the second funding period.

Although gravity waves have comparatively short wavelengths of between just a few hundred metres and several hundred kilometres, at times they influence the transport of water vapour as well as large-scale winds and temperature distributions to a considerable degree. This effect is strongest in the upper layers of the atmosphere. These, in turn, have such a strong effect on the lower layers too that a realistic modelling of weather and climate in the atmosphere is impossible without giving due consideration to gravity waves. Gravity waves also play a significant role for air traffic in predicting turbulence and are an important factor in weather extremes, such as heavy rain or storms.

In the first funding period, the ten research institutes participating in the project documented in detail the formation of gravity waves in one of the largest measuring campaigns ever undertaken, using radar, high-performance lasers, rockets and research planes as well as through laboratory tests. They also refined the hypothesis on the formation and dispersion of gravity waves to such an extent that their development can now be reproduced much more reliably in high-resolution numerical models too.

In a further step, the research unit led by Professor Ulrich Achatz of the Department of Atmospheric and Environmental Sciences at Goethe University Frankfurt has used these findings to improve parameterizations, which serve to describe the influence of gravity waves, in weather and climate models with typically coarser resolution. They have refined the weather and climate model ICON used by Germany's National Meteorological Service (DWD) and the Max Planck Institute for Meteorology. The new model, UA-ICON, allows more precise predictions for the upper atmosphere and can be operated with different resolutions, so that gravity waves can either be simulated in it for test purposes or must be parameterized in the operational mode. The advanced parameterizations are now being integrated in this model and tested in the second funding period.

The project will also focus on impacts on weather prediction and climate modelling. An important aspect in this context is a better description of the interaction between gravity waves and ice clouds (cirrus), undertaken in cooperation with the University of Mainz. It could well be that this plays an important role for the climate.

Further information: Professor Ulrich Achatz, Department of Atmospheric and Environmental Sciences, Faculty of Geosciences and Geography, Riedberg Campus, Tel.: +49(0)69-798-40243, achatz@iau.uni-frankfurt.de.

FRANKFURTAtherosclerosis, the most frequent cause of death in the western world, usually starts with an inflammation of arterial endothelial cells, a process that affects the structure and function of blood vessels and may ultimately lead to an acute heart attack or stroke. It is still unclear so far how endothelial cells “sense” the environmental stimuli and how pro-inflammatory processes are controlled. With the help of an ERC Starting Grant of € 1.5 million awarded by the European Research Council, Professor Konstantinos Stellos of Goethe University Frankfurt now plans to examine the process at single nucleotide-level of RNA molecules.

Increasing recent evidence suggests that RNA is not just a passive copy of the genetic code necessary for the production of proteins, the building blocks of cells, but also important for regulating intracellular transport and stability of genetic information, thus allowing or inhibiting its decoding to proteins. Even today, how RNA reacts to its ambient surroundings is not fully understood. For example, it is still far from clear whether chemical modifications to the RNA have an influence on gene expression, endothelial cell function and therefore on atherosclerosis.

The research group led by Konstantinos Stellos from the Institute of Cardiovascular Regeneration and the Department of Cardiology at Goethe University Frankfurt has observed two particularly common chemical modifications in the RNA of endothelial cells that occur in atherosclerosis. His intention now is to investigate another RNA modification in detail, namely the impact of RNA methylation on blood vessel function.

The researchers aim to increase our understanding of how RNA methylation affects gene expression, which proteins play a role in this context and what impact RNA methylation has on vascular inflammation and atherosclerosis. Their findings will be further “translated” into patients with coronary heart disease. They also hope to detect biomarkers which reveal early signs of atherosclerosis in the general population as well as develop new therapeutic strategies for this common disease.

Konstantinos Stellos completed his medical degree in Greece in 2005 and two years later his doctorate at the University of Tübingen. His “habilitation” (postdoctoral lecture qualification) followed in 2013 at Goethe University Frankfurt. Since 2013, he is board-certified cardiologist and group leader at the Institute of Cardiovascular Regeneration of Goethe University Frankfurt.

With the ERC Starting Grant, the European Union funds excellent early-career scientists after their doctorate so they can launch an independent career and establish their own research team.

Further information: https://erc.europa.eu/news/erc-2017-starting-grants-results or www.stelloslab.com

FRANKFURT. Making valuable products, such as fuels, synthetic materials or pharmaceuticals, from renewable raw materials is to date not efficient enough because the microorganisms used only process the raw materials very slowly and generate many by-products in addition to the substances actually wanted. Biotechnologists at Goethe University Frankfurt have now succeeded in optimizing sugar utilization in baker’s yeast.

Microorganisms such as baker’s yeast can be compared to a miniature factory: the raw materials (generally sugar) are carried in through gates (transport proteins) and converted in a multi-stage process with the help of enzymes. By contrast to a man-made factory, in microbes not only technologically interesting products are turned out but also many by-products. This is due to the fact that various enzymes compete for the sugar so that different building blocks important for the cell’s survival are formed.

Thomas Thomik and Dr. Mislav Oreb from the Institute of Molecular Biosciences at Goethe University Frankfurt have now succeeded in channeling the metabolism of baker’s yeast in such a way that sugar, as the raw material, can be used more productively. In the latest issue of the renowned scientific journal “Nature Chemical Biology”, the researchers present a new mechanism with which the raw materials are delivered directly to the desired enzymes by transport proteins.

Mislav Oreb explains the principle: “We have built a ‘scaffold protein’ that binds to the transport protein and then serves as a docking station for the desired enzymes. Recognition codes in the enzymes enable them to dock. The result is an accumulation of the desired enzymes near the transporter. In this way, the cell can process the raw material like on a conveyor belt, without the competing enzymes having a chance to convert it.”

In their study, the biotechnologists show that the sugar xylose is converted into ethanol by such “molecular conveyor belts” (transport metabolons) more efficiently by minimizing the production of the unwanted by-product xylitol.

“The underlying principle could be used to make any manner of product from various sugars, such as biofuels, synthetic materials or pharmaceuticals. The concept has the potential to make biotechnological processes generally more ecologically and economically sustainable, since efficient sugar utilization is a fundamental requirement for this,” says Mislav Oreb, explaining the significance of the new process.

A picture can be downloaded under: www.uni-frankfurt.de/68258883

Caption: In baker’s yeast, various enzymes compete for sugar molecules that are introduced into the cell by transport proteins. So that the sugar is converted only by enzymes that deliver products desirable from a biotechnological perspective (green ovals), these are connected to the transporter directly via a docking station (picture on the right).

Publication

Thomas Thomik, Ilka Wittig, Jun-yong Choe, Eckhard Boles and Mislav Oreb: An artificial transport metabolon facilitates improved substrate utilization in yeast, in Nature Chemical Biology

Further information: Dr. Mislav Oreb, Institute of Molecular Biosciences, Faculty of Biological Sciences, Riedberg Campus, Tel.: +49(0)69-798-29331, M.Oreb@bio.uni-frankfurt.de.