(Patho)physiologische Rolle von mitochondrialen Präsequenzproteasen(S. 260)
Chris Meisinger, F.-Nora Vögtle
Mitochondria are essential organelles that import more than 1.000 different preproteins from the cytosol. N-terminal presequences serve as targeting signals for most preproteins. Proteases specialized for processing and turnover of presequences in the mitochondrial matrix build a control system to ensure proper maturation of these preproteins in order to maintain a functional organellar proteome. Imbalance of this control system seems to play a role in various diseases.
Einblicke in das Sozialleben von Mikroben(S. 264)
Theresa Hülscher, Christian Kost, Ákos T. Kovács
The evolution of cooperation is an intriguing puzzle in evolutionary bio - logy. Several examples have been described where individual microbial cells cooperate by secreting products that are beneficial for the whole community, but reduce the fitness of the producing cells. The spatial distribution within the community provides a solution that can explain the evolution and stability of cooperative interactions.
Stoffwechsel mariner Ammoniakoxidierender Archaeen(S. 267)
Archaea are ubiquitous in the ocean and account for 20 percent of all planktonic microbes. Most of them belong to the phylum Thaumarchaeota and are chemolithoautotrophes, oxidizing ammonia as energy and fixing CO2 as carbon source. Ammonia-oxidizing archaea are now recognized to primary control the initial and rate-limiting step of nitrification in the ocean. A high substrate affinity to ammonia and the most energy-efficient aerobic pathway for autotrophy enable them to thrive in nutrientlimited environments, typical of most of the open ocean.
Sex und Penicillin-Biosynthese in Schimmelpilzen(S. 270)
Ulrich Kück, Kordula Becker, Julia Böhm, Tim Dahlmann
Penicillium chrysogenum is the only industrial producer of the β-lactam antibiotic penicillin. Like many other biotechnologically relevant fungi, it has been considered to be asexual, since no sexual propagation has been observed under laboratory conditions. The discovery of a sexual life cycle, the functional characterization of mating-type encoded transcription factors, and a comparative genomic analysis, however, will facilitate further improvement of P. chrysogenum strains used for industrial applications.
Leben und sterben lassen – horizontaler Gentransfer in Vibrio cholerae(S. 273)
There is a fundamental gap in our understanding of how horizontal gene transfer contributes to the enormous range of genetic variations that are observed among bacteria. Our model organism is Vibrio cholerae, the causative agent of cholera. V. cholerae enters a natural competence state for the uptake of DNA in response to environmental signals. Our objective is to better understand the regulatory circuits that drive competence in this organism and the mechanistic aspects of the DNA transfer and uptake process.
Think small – Methoden zur in vitro-Evolution von Polymerasen(S. 278)
Rita Gerardy-Schahn, Timothy G. Keys
Polysaccharides are abundant extracellular matrix components and ideal materials for next-generation bioprostheses. Because the chain length critically impacts polymer properties, biotechnological production requires enzymes that allow polymer length control. For the capsule polymerase from Neisseria meningitidis serogroup B, we describe here the switching from processive to distributive polymer elongation. Our methodology delivered a finely tuned enzyme with narrow product distribution even in the absence of advanced high throughput screening platforms.
Mikroben zur Herstellung monoklonaler Antikörper und Antikörperfragmente(S. 281)
Oliver Spadiut, Christoph Herwig
Mammalian cell cultures are currently employed for the production of monoclonal antibodies and antibody fragments mainly due to the ability of performing the required human-like N-glycosylation. However, several drawbacks are tied to production processes with mammalian cells. Furthermore, typical process times are rather long. Antibody fragments can alternatively be produced in microbes, which are easy to cultivate. Recent advances in antibody and antibody fragment production have been obtained in Pichia pastoris and Escherichia coli.
Dynamische Proliferationsanalysen mittels Durchflusszytometrie(S. 285)
Two key parameters of (eukaryotic) cell culture are cell vitality (survival) and proliferation which both determine the rate of cell multiplication. The proliferation capacity (S-phase fraction) of a given cell population can be easily evaluated by flow cytometry in a static manner. Dynamic proliferation assessment is, however, much more powerful since it reveals profound kinetic information and allows insight into the cell cycle regulation. In particular it is extremely helpful for drug screening.
Wie unser Blut entsteht – neue Erkennt nisse zur Hämatopoese(S. 290)
André Görgens, Bernd Giebel
Via different committed progenitors, hematopoietic stem cells produce all mature blood cells. The classical model of hematopoiesis predicts multiple binary bifurcations, the first of it resulting in the separation of lymphoid and myeloid cell lineages. Combining complex flow cytometric analyses, fluorescent cell sorting and functional single cell analyses, we recently uncovered unexpected lineage relationships in human hematopoiesis, which let us propose a revised model for human hematopoiesis.
Referenzverfahren zur Messung von Stammzellkonzentrationen(S. 294)
Jörg Neukammer, Martin Kammel, Jana Höckner, Andreas Kummrow, Andreas Ruf
Reference measurement procedures are indispensable to reliably determine blood cell concentrations, since medical diagnosis, initiation of therapy and control of blood products are often based on concentration limits of specific cell subpopulations. We have developed a reference procedure to directly determine stem cell concentrations. In the same measurement both established routine protocols, i.e. relative enumeration with respect to calibration particles or leukocytes, are simultaneously applied.
Anwendungen & Produkte
Funktion von TPR-Proteinen beim Proteintransport(S. 306)
Serena Schwenkert, Jürgen Soll, Ismail Moarefi
TPR docking proteins are found in all organisms and mediate a first contact between preproteins/preprotein chaperone complexes and the import apparatus. We are analyzing the role of these docking proteins in post-translational protein import on a functional and on a structural level. Insights are provided by a biophysical method called microscale thermophoresis (MST) and structural studies of recombinant protein peptide complexes.
Inflammation und Metastasierung von Tumorgeweben(S. 308)
Ralf Ketterlinus, Silke Schwengberg, Leyna Zhao
The study of dynamic cellular processes demands appropriate test systems. While static endpoint measurements fail to reflect kinetic variation, a real-time system provides comprehensive insights into cellular migration and invasion processes. Here we present how this method has been applied to study inflammation, and cancer metastasis.
Cluster-Screening – eine effiziente Methode zur Identifizierung neuer Enzyme(S. 344)
Sustainable production of high valuable chemicals is of increasing eco - logical and economical importance. Highly specific customized enzymes with improved performance tailored for particular requirements are still in high demand. Combining the enormous potential of natural diversity with the ability to design highly representative (meta)genomic libraries together with a rapid and innovative activity-based screening method can open access to a huge amount of novel and specific biocatalysts.
Vom Schüttelkolben in die Pilotanlage: Enzymherstellung in Hefen(S. 347)
Nicole werner, Björn Vater, Tino Elter, Katja Patzsch, Susanne Zibek
The market for industrial enzymes is increasing steadily. Hence, efficient expression systems and processes for the large-scale production of industrial enzymes are of common interest. The presented article deals with the recombinant production of a fungal lipase in yeasts, and with its large-scale, fermentative production up to 1.000 Litres.