Press Release
28 Jun 2011 at 08:39
Bonn, 28.06.2011. Gaining a better understanding of neural processes at ultrastructural level - this is the goal of scientists led by Dr. Ashraf Al-Amoudi at the German Centre for Neurodegenerative Diseases (DZNE) and the research center caesar. To this end, Dr. Al-Amoudi investigates the organization and the interactions of key proteins in living cells using electron microscopy. With caesar’s purchase of a new cryo-electron microscope, the scientists are now well-equipped to tackle this challenge. The high-end microscope is supported by Dr. Stephan Irsen at caesar.
The main focus of Al-Amoudi’s work is to analyze, at the ultrastructural level, how contacts between neurons, called synapses, are modulated and altered in neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases. In addition to the study of neurodegenerative diseases, Al-Amoudi’s group closely collaborates with Prof. Ulrich Benjamin Kaupp at the research center caesar to investigate, at the molecular level, how photoreceptor cells of the retina accomodate different light conditions, in normal and diseased states.
An electron microscope has a much higher resolution than a light microscope, and it permits the analysis of cellular structures at the molecular level. In addition, cryo-electron microscopy technology allows the investigation of biological samples under near-natural conditions. To do so, the samples are not fixed or chemically treated, but are frozen very quickly, so that tissue-damaging ice crystals will not form. Dr. Al-Amoudi has contributed significantly to refining the cryo-electron microscopy technology. "To analyze frozen tissue with high resolution, samples are cut at low temperature into very thin slices of 50-100 nm and examined in the microscope," Al-Amoudi explains. "In small steps, the sample is tilted inside the microscope and imaged at different angles. This allows us to obtain a three-dimensional image of protein complexes inside the cell at nanometer resolution."
The new microscope with the name Titan KRIOS FEI is programmable and can be remotely controlled; this considerably abbreviates the extremely time-consuming imaging procedure. Dr. Irsen explains: "Our microscope is equipped with a new camera. This is more than three times as sensitive as conventional detectors. In addition, the KRIOS possesses a so-called CS corrector, which reduces the lens errors of the microscope. Thus, the quality of the images is significantly improved."
Ashraf Al-Amoudi studied at the University of Birzeit in the West Bank, Palestine and completed his dissertation the University of Lausanne. During his PhD work, he developed the method CEMOVIS, which he applied to various biological samples, also in his subsequent postdoctoral studies at the European Molecular Biology Laboratory (EMBL) in Heidelberg. In 2010, he moved to Bonn to take up a position as a joint group leader of the DZNE and the research center caesar.
