News

News & Press releases 2014

Blockade with serious consequences

A common symptom of Alzheimer's disease (AD) is the accumulation of a special peptide, the so-called Amyloid-Beta (in short Ab), in the patients' brains. However, it is still unclear how this peptide damages the brain. A team of scientists involving the Systems Analysis group at ISAS now believe that they have discovered a respective mechanism in mitochondria.

Mitochondria are called the cell's power plants. They contain ten percent of all the proteins in a cell – about 1000 different protein types. But they only produce a small part of them, so they have to import the rest from cytoplasm into their matrix.

To enter the mitochondrial matrix, the proteins have to pass the inner and outer membrane first. They are marked with an additional sequence of 27 to 86 amino acids – a kind of postal code that tells the cell machinery where to transport the protein – to prevent the wrong substances from entering the mitochondrion. Receptors on the membrane recognize those signalling sequences and help the proteins pass. Inside the mitochondrial matrix enzymes extract and split off the presequence so that the now mature protein can assume it's function – at least in a healthy organism.

In AD patients this mechanism seems to be disturbed. A research team – including, amongst others, scientists from ISAS and from the universities in Freiburg, Stockholm and Graz and the Swedish Karolinska institute – were able to show that Amyloid-Beta inhibits the respective mitochondrial enzymes, thus preventing them to cleave off the "postal code". Therefore the proteins change or lose their usual function and disturb the mitochondrial balance. Those findings match earlier observations on mitochondrial dysfunction in AD patients.

The results of this study have been published at the end of August in "Cell Metabolism" (> Link to the paper - login required). In future, they might simplify and optimize diagnosis and treatment of AD patients.

Vesicles instead of stem cells as a new therapeutic approach

Researchers from ISAS and their clinical partners plan to considerably change stem cell therapy with a new therapeutic concept: They believe that it's not only the cells themselves that help healing diseases such as stroke or graft versus host disease, but also the molecules they release into their surroundings. 

This press release (PDF) is available in German only.

Stopping platelets

In a new DFG project titled "New protein kinase A and G-dependent signaling pathways and networks in the regulation of platelet activation", the Bioanalytics department takes a close look at platelets - those anucleate blood cells that help closing injured blood vessels - and their role in therapies for stroke and heart attacks.

Platelets are crucial for blood coagulation, but they can also cause severe health issues: If they pass through blood vessels that are already constricted, for instance due to organic depositions – a condition known as arteriosclerosis – they can be activated in the wrong place at the wrong time and build up clots. Those can in turn cause thrombosis and thus lead to heart attacks or stroke. Therefore, anticoagulants such as aspirin have been used in infarct and stroke therapy for a long time. However, those drugs do not only help to avoid further vascular clogging but also block normal blood coagulation in injuries.

A new therapeutic approach would have to selectively stop clogging without affecting normal wound healing. And indeed, vasculature itself has a promising inhibitory system, but it is not yet understood and therefore not utilizable for medical purposes. This is the point where ISAS researchers and their project partners from the Center for Thrombosis and Hemostasis (CTH) in Mainz step in: They plan to have a closer look at the activities of two protein kinases, PKA and PKG. Those enzymes attach phosphorylations to their target molecules (also called substrates) and thus trigger signaling cascades. The project aims for a thorough characterization of all PKA and PKG substrates to find out how they affect different platelet functions. To this end the scientists employ methods for a quantitative analysis of phosphorylation networks that were developed at ISAS. The institute will receive nearly 190,000 Euros for the three-year project.

Outstanding Career Award for Dr. Alex von Bohlen

Great honor for Dr. Alex von Bohlen: The ISAS scientist gets an "Outstanding Career Award" for his work in X-ray spectrometry. The prize is awarded biennially by the European X-Ray Spectrometry Association (EXSA). This year's award ceremony will take place in Bologna on June 19 during the EXSA conference.

This press release (PDF) is available in German only.

ISAS Annual Report 2013 now online

To get to the download area please click > here

A closer look: How scientists visualize molecule interactions

So called "new" or functional materials often display special characteristics that are closely linked to their structure on the nano scale. The molecules in such materials can, for example, organize themselves, but can also be specifically stimulated by temperature or pH changes. Thus they are interesting candidates for applications such as organic solar cells or biosensors.

It is a major aim of research on new materials to understand and be able to control those characteristics. However, so far there were no infrared spectroscopy methods and analyses available that offer the necessary spatial and spectral resolution. This gap has now been closed by a team of researchers including Dr. Karsten Hinrichs from ISAS Berlin. A key role played the combination of the imaging technique called "infrared near field microscopy" which is developed in the group of Professor Markus B. Raschke at the University of Colorado in Boulder, USA, with infrared ellipsometry measurements at ISAS Berlin. In "Nature Communications" the scientists describe how they were able to gain unprecedented insights into local chemical environments of nanostructures such as the so called solvato-chromatic influence of neighboring molecules.

The paper titled "Vibrational nano-spectroscopic imaging correlating structure with intermolecular coupling and dynamics" (B. Pollard et al., Nat. Commun. 5, 3587) is available on the
> journal website.

New micro-spectroscopic methods at ISAS Berlin

ISAS Berlin has a new application lab: In a three-year project, ISAS scientists have developed novel micro-spectroscopic methods to characterize ultrathin layers with higher spectral range, resolution and sensitivity and time-dependent processes with better temporal resolution. The project titled "New concepts for vibrational spectroscopy on nanoscopic materials" was funded by the state Berlin from the European Funds for Regional Development (EFRE).

The scientists were able to set up a Raman microscope at ISAS that covers a much wider spectral area than similar commercialized devices. They also installed an infrared microscope that is now used to analyze ultrathin layers, such as in functional surfaces. Also, a novel Echelle spectrograph for parallel detection of the MIR spectrum (mid-infrared) was developed and successfully tested; it can be coupled to the microscope platform and provides a temporal resolution in the range of milliseconds.

This combination of methods will permit new applications in microfluidics and on biosensors as well as investigations on semiconductor nanostructures or the marker-free detection of organic molecules. The efficiency of the measure concepts has already been demonstrated on organic and anorganic nanofilms. Capturing extremely fast time-dependent processes is especially important for bioanalytics and ohysical chemistry.

In addition to applications in basic research, a commercialization of the measure concepts is planned.

 

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