Apart from research within these institute programmes, members of the Section Parasitology have continued research on leishmaniasis and malaria, major tropical diseases where the control has become more complex with the global rise of drug resistance. Emphasis is given to research toward a better understanding of the cell biology and biochemistry of these pathogenic agents with the aim of vaccine and drug development.

With the aim of antimalarial drug discovery the Biochemical Parasitology Unit continued research on the polyamine metabolism and the thioredoxin system, one of the major thiol reducing systems of cells. To obtain a better knowledge about the catalytic process, the crucial role of the C-terminal cysteines of the plasmodial thioredoxin reductase in the substrate coordination and electron transfer during reduction of the peptide substrate was analysed. The investigation of the polyamine synthesis in Plasmodium falciparum identified a transcript that encodes in a single open reading frame ornithine decarboxylase and S-adenosylmethionine decarboxylase, enzymes which in other organisms are individually transcribed and highly regulated as monofunctional proteins. This unique organization may be exploitable for the design and development of new antimalarial drugs. The Leishmaniasis Unit continued the research into the role of the cellular heat shock response during the mammalian stage of Leishmania parasites. In genetic selection experiments gene fragments were isolated from Leishmania donovani which confer added heat stress protection and improved persistence in a mammalian host. Furthermore, a novel member of the Hsp60 family of stress proteins in Leishmania was identified, and its subcellular localization and stage-specific expression pattern was analysed.

Additional research topics addressed by other research groups of the section included the investigation of the folding and assembly of heptahelical membrane proteins focussing on the prototypic member bacteriorhodopsin. It was shown that several of the transmembrane regions are partially misfolded in isolation, implying that their conformation is specified by interactions with neighbouring helices. In addition, work on the regulatory mechanisms of the human immune response was continued. The role of the EGR-transcription factors in the regulation of cytokine gene expression was analysed and a model system established to study the functional interaction of these nuclear immunoregulartory proteins with other cellular transcription factors. In addition, the role of the human complement regulators Factor H and the additional members of the Factor H protein family are studied to identify their involvement and molecular function during infection and during protection of host tissues. Further, studies focussing on the improvement of microsporidia detection have been successful and these methods have now been implemented in the routine diagnosis.

Rolf D. Walter

Scientific Staff Prof. Dr. Rolf D. Walter,     Chairman and Head Biochemical Parasitology Prof. Dr. Dietrich W. Büttner,     Head Department of Helminthology and Entomology Privatdozent Dr. Joachim Clos,     Head Leishmaniasis Research Privatdozent Dr. Egbert Tannich,     Coordinator Amoebiasis Programme Dr. Otto Berninghausen Dr. Iris Bruchhaus Dr. Heike Bruhn Dr. Frank Ebert Privatdozent Dr. Klaus D. Erttmann Dr. Peter Fischer Dr. Elke Fleckenstein Dr. Michaela Gallin Prof. Dr. Rolf Garms Privatdozentin Dr. Kimberley J. Henkle-Dührsen Dr. Sylvia Krobitsch Dr. Thomas F. Kruppa Privatdozent Dr. Matthias Leippe Dr. Eva Liebau Dr. Hannelore Lotter Dr. Jürgen Lüneberg Dr. Thomas Marti Dr. Sylke Müller Prof. Dr. Justus Schottelius Privatdozentin Dr. Christine Skerka Dr. Gabriele Wildenburg Dr. Ute Willhoeft Privatdozent Dr. Peter F. Zipfel Visiting Scientists Dr. Wolfgang Prodinger Institute for Hygiene and Microbiology, University of Innsbruck, Austria Dr. Sakari T. Jokiranta Haartman Institute, University of Helsinki, Finland Amabir Singh Sidhu, Jawaharlal Nehru University, New-Delhi, India Anna Timanova-Gospodinova, Bulgarian Academy of Sciences, Sofia, Bulgaria

Immune electron microscopy of a Leishmania donovani promastigote stained with anti-Cpn60.2 antibodies and 10 nm protein-A gold particles: the heat shockprotein Cpn60.2 (GroEL) localizes to the mitochondrial matrix of the parasite. n = nucleus; mt = mitochondrium; fl = flagellum