Talmon Arad


 

Mr. Talmon Arad / 1938-2019

In Memoriam

 Prof. (Emeritus) Martin Kessel (Hebrew University of Jerusalem & National Cancer Institute, NIH) :

“Talmon Arad has a unique place in ISM history having begun as a technician at the Hebrew University School of Applied Science in 1972. A remarkable number of publications some in collaboration with researchers from the School of Dentistry (Yona Sela) using the SEM resulted from his work. He worked at that time with Avi Ben Hur who continues today as a senior technician at the HU Nanaocenter.

The next phase of his scientific life was to join the European Molecular Biology Laboratory (EMBL) in Heidelberg where he worked as technician in the Structural and Computational Biology Unit for Kevin Leonard, whose task it was to build an electron microscope lab. His paper together with Kevin Leonard and Ada Yonath gave us the first glimpses of the organization of ribosome crystals.

Upon his return to Israel in 1984 Talmon joined the staff of the EM Unit and was responsible for the introduction of CryoTEM to the lab – the second in Israel after the lab established by Prof. Ishi Talmon at the Technion. Talmon Arad was the first person doing EM tomography at the Weizmann Institute of Science with almost homemade equipment from Hans Tietz.Talmon worked until his retirement at the EM Unit at the Weizmann Institute.

He will be sadly missed.”

 Prof. Steve Weiner (Weizmann Institute) :

“Talmon Arad, Wolfie Traub and I worked together for well over a decade starting in the 1980s on structural problems related to the field of biomineralization. The results obtained reflected Talmon’s truly exceptional capabilities as an electron microscopist who understood very well where this field was heading. He was a virtuoso when it came to low dose imaging, especially with cryo-preserved specimens. Together with Ilana Sabanay and Benny Geiger, we developed a method for examining vitrified antibody labelled thin sections. We also naively immersed ourselves in the world of 3D tomographic imaging, using a goniometer donated to us by Wolfgang Baumeister. I didn’t fully realise at the time, but during these years we, with Talmon in the driving seat, were helping lay the foundations for cryo-electron microscopy at the Weizmann Institute.

I would say that Talmon has three major legacies – the numerous students whom he taught electron microscopy, many of whom are prominent in the electron microscopy field throughout the world. Laying the foundations for cryo-microscopy that is still a hallmark of EM research at the Institute. The third legacy is perhaps overlooked. Talmon and the other pioneers of the Weizmann EM Unit created this tradition of establishing a very special team relationship between the students, post-docs, PI’s and the EM Unit members. This teamwork is certainly a key factor in the research that my colleagues and I carried out with Talmon. But for me the relationship went well beyond a team member. Talmon was a friend whom I always enjoyed working with, discussing the results with and, as so often happened, struggling together to get some good results. In desperation, we often pleaded with the “gods” to give us just one good image (the proverbial figure 1). With Talmon at the helm, there were almost always many more good images once he cracked the problem.

I miss Talmon the great microscopist, the colleague, the friend and as always the gentleman.”

Prof. Paul Wingfield (Bethesda, Maryland) :

“I joined the EMBL in June 1977 and we were temporary housed in University of Heidelberg laboratories in the town center until we moved to the newly constructed laboratory in 1978. My Boss was Hanns Weiss whose research focus was on the isolation and characterization of mitochondrial membranes complexes and in particular Ubiquinol: cytochrome c reductase This is a major enzyme complex (III) of the mitochondrial oxidative phosphorylation system. The enzyme catalyzes the electron transfer from ubiquinol to cytochrome c and utilizes the energy of the redox reaction to translocate protons across the mitochondrial inner membrane. Hanns developed a very eloquent method for isolating the multiprotein complex using cytochrome c affinity purification and it was task to make 3-D crystals for structure determination. The complex was dimeric in Triton-X micelles and we reconstituted the protein into phospholipid bilayers. During this process the solutions became opalescent – cloudy and we resolved the lipoprotein complexes by density gradients. The reconstituted membranes were routinely checked by Talmon using negative stain EM. I cannot remember exactly what we did differently but after one particular round of reconstitutions, Talmon became very excited as he showed me the large sheets of ordered protein complexes in crystalline arrays. After several days of checking samples he was convinced we had 2-D crystalline arrays which were checked for diffraction by Kevin Leonard. The crystals were well suited for three dimensional image analysis by electron microscopy which were performed by Talmon. We published our initial findings in Nature (1979) and followed this up with more detailed description in JMB (1981). This was the first time a membrane protein of this complexity had been isolated and then reconstituted for structural determination, albeit at relatively low resolution ~ 20-25 A.”

Cytochrome c Reductase Dimer The French Model: cytochome c1 (red) cytoplasmic side of inner membrane; central region (white) membrane containing cytochrome b and iron-sulphur proteins; water soluble subunits on matrix side of membrane (blue).

“Talmon was a wonderful and supportive colleague, sharing both his technical knowledge and enthusiasm. The early days of the EMBL was a very happy place for young scientists and I shall always remember with great fondness and gratitude that I worked with and knew Talmon Arad.”

 

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