Molekulare Thermometer zur Steuerung der Virulenz von Yersinia(S. 376)
Ann Kathrin Heroven, Petra Dersch
The ability to sense the temperature of surrounding environments is a prerequisite for many bacterial pathogens to adjust their virulence program to establish an infection. Pathogenic Yersinia species use intrinsic thermosensing protein domains and mRNA secondary structures of crucial virulence regulators to activate essential colonization factors during the early infection stage and induce antiphagocytic strategies to prevent attacks of the innate host immune system during the ongoing infection.
Phagen in Sedimenten der marinen tiefen Biosphäre(S. 380)
Bert Engelen, Tim Engelhardt, Heribert Cypionka
Deep marine sediments harbor huge numbers of prokaryotes that are involved in the global elemental cycles. This “deep biosphere” is prone to increasing energy limitation with depth. Phages are probably the main “predators” for microbial life in the subsurface and provide nutrients due to lysis of infected cells. Their numbers always exceed the total cell counts by factors of up to 225 indicating ongoing virus production. At this high ratio, up to 80 percent of all biomass is virus-bound.
Relaxationskinetik in lebenden Zellen(S. 383)
Steffen Büning, Simon Ebbinghaus
Fast kinetics of biochemical reactions can be measured in vitro using relaxation experiments. Recently, temperature jump techniques have been developed that can also be applied for in-cell studies. The high spatio-temporal resolution of such experiments leads to new insights of how the cellular environment modifies reaction kinetics.
Bakterien gefangen im Licht(S. 386)
Alexander Rohrbach, Matthias Koch, Julian Roth
Bacterial locomotion is often related to pathogenicity and the spread of diseases. Bacteria are able to move under various environmental conditions, and their complex motions are often too fast and minute to be quantitatively imaged with conventional microscopy techniques. The study of their locomotion principles requires new, advanced photonic measurement techniques, capable of extracting forces and energetics exerted by the cell on time scales ranging from milliseconds to a couple of minutes.
Toxingen-Profiling bei Bakterien der Bacillus cereus-Gruppe(S. 390)
Ulrich Busch, Ute Messelhäußer, Maria Butzenlechner
Differentiation of bacteria of the Bacillus cereus group often plays a minor role in the area of food microbiology, especially in routine laboratory diagnostics. Bacteria of the B. cereus group are more often used as hygienic parameter; however, a thorough risk assessment with respect to their potential for causing foodborne illnesses is frequently neglected. The detection of different toxin gene profiles of presumptive B. cereus strains allows a comprehensive risk assessment in the context of pre - ventive consumer protection.
R-Spondine: Einblicke in die Potenzierung der Wnt-Signaltransduktion(S. 395)
Matthias Zebisch, E. Yvonne Jones
Intercellular signalling by Wnt morphogenetic proteins is subject to a multi-layered system of regulation. The four secreted R-spondin proteins potentiate Wnt signalling in vertebrates. They are involved in embryogenesis, adult stem cell biology and cancer progression and have been proven essential for ex vivo culturing of organoids. Recent research has generated profound new insights into how R-spondins function to stabilize Wnt receptors of the Frizzled family at the cell surface.
Die molekulare Entschlüsselung un konventioneller Sekretionsmechanismen(S. 400)
Julia P. Steringer, Hans-Michael Müller, Walter Nickel
The vast majority of secretory proteins is characterized by N-terminal signal peptides that allow for co-translational translocation into the lumen of the endoplasmic reticulum, the initial compartment of the classical ER/Golgi-dependent secretory pathway. However, extracellular proteins with fundamental physiological functions in immune surveillance and tissue organization have been identified that lack signal peptides. The molecular mechanisms by which these unconventional secretory proteins reach the extracellular space are beginning to emerge.
Humane 3D-in vitro-Testsysteme für die präklinische Forschung(S. 404)
Angela Rossi, David Fecher, Sebastian Egner, Matthias Schweinlin, Maria Steinke
In vitro test systems have to be optimized to reduce preclinical failure rates. Therefore, we have introduced a new innovative system which mimics physiological conditions and enables vascularisation in bioreactors. Thus, we have developed test systems for intestinal uptake studies, for airway infections and for different tumour entities, e. g. lung cancer. A further approach presents the ex vivo cornea test system for irritation studies.
Anwendungen & Produkte
Gewinnung haploider Stammzellkulturen der Maus für genetische Screens(S. 416)
Remo Freimann, Stefan Kramer, Andreas Böhmler, Anton Wutz
Haploid mouse embryonic stem cells are a handy tool to investigate loss of function mutations. Furthermore, these cells can contribute to chimeric embryos and can be used to introduce genetic modifications into mouse germ lines. Nevertheless, haploid cell cultures have to be maintained by flow sorting on a regular basis due to spontaneous diploidization. Here we present physical differences between haploid and diploid cells, which can be used in applied cell sorting of haploid cell cultures.
Ultraschallbasiertes Liquid-Handling in der Wirkstoffforschung(S. 419)
Rainer Heller, Jan Carsten Pieck
Acoustic liquid handling plays an increasing role as alternative to classic pipette tip or pin tool based liquid handling systems. This new method allows a precise, contact-free transfer in the sub-microlitre range, directly from a compound storage into an assay plate without intermediate dilution steps. The sound based transfer technology of acoustic liquid handling creates new quality requirements for microplates used in compound or sample storage. The microplate bottom thickness homogeneity and the selected material do have major impact on the transfer process.
Charakterisierung pflanzlicher in vitro- Kulturen am Beispiel Sonnenblume(S. 450)
Katja Geipel, Thomas Bley, Juliane Steingroewer
In advance of industrial applications of in vitro plant cell or tissue cultures e. g., as bioactive ingredients for pharmaceuticals, an intense characterization concerning growth and productivity has to be performed. Innovative respiration measurement techniques in shake flask scale were applied to investigate and compare heterotrophic, photomixotrophic and hairy root cultures of sunflower. Furthermore, the qualification of a monitoring system for screening of plant in vitro cultures is discussed.
3D-Epoxyoberflächen für DNA-codierte Proteinarrays(S. 453)
Oda Stoevesandt, Ronny Schmidt, Uwe Schedler, Christian Heise
The DNA-array to protein-array technology (DAPA) allows the direct transcription and translation of a coded DNA-array to a protein array in the presence of a cell free expression system. The coupling efficiency of DNA and of the corresponding immobilized proteins is enhanced by using 3-dimensional epoxy surfaces. The production time of protein arrays is considerably reduced and the DNA template array can be reused for producing further protein arrays.
Bäckerhefe Saccharomyces cerevisiae als universelle chemische Mikrofabrik(S. 456)
Jutta Heim, Thomas Østergaard Tange, Jens Klein
One of the applications of the emerging synthetic biology field is the enzymatic production of chemicals, either by individual enzymes or by cascades of whole metabolic pathways. Here, the discovery of novel metabolites from baker’s yeast transformed with yeast artificial chromosomes is described. One particular class of compounds found repeatedly are structurally diverse novel polyketides obtained by expression of mixes of PKSIII (polyketide synthase type III).
Vom Fed-Batch-Screening bis zur chiralen Analytik(S. 460)
Thomas Grimm, Peter Neubauer
An efficient screening system could be established, which allows a fast test of microbial strain collections for new catalytic activities. This was developed by the combination of methods of the high-cell-density cultivation with on-line sensors followed by whole cell biotransformation with chiral gas chromatography. Here we describe the application of the system in a screening with different yeasts for the biotransformation of chiral alcohols.
Innovative Produktion pharmazeutischer Proteine in Pflanzen(S. 464)
Johannes Felix Buyel, Andreas Reimann, Jürger Drossard, Rainer Fischer
The release of the pharmaceutical product Elelyso showed that plantderived biopharmaceuticals can compete economically with products from conventional expression systems. Improvements are required in terms of automation, consistency and purification as well as quality control and regulatory compliance to ensure a successful commercialization of biopharmaceuticals from plants and plant cells. Here we discuss possible improvements and challenges, which will affect the development of the molecular farming approach.
Zukunftstechnologie mit noch mehr Schub(S. 467)
„Wie viel mannigfaltiger werden sich die Erscheinungen gestalten, wenn es gelingt, das chemische Baumaterial der Zelle zu verändern, sie gleichsam chemisch zu betrügen? Gewiß wird dazu viel List des Experimentators gehören: Aber wenn heute Biologe und Chemiker sich verbinden und die Aufgabe mit richtigen Mitteln am passenden Objekte anfassen, dann ist der Erfolg nicht so unwahrscheinlich. So sehe ich denn, halb im Traum, eine chemisch-synthetische Biologie entstehen, die der Lebewelt ebenso gründlich ins Handwerk pfuscht, wie es die Chemie, Physik und Technik mit der leblosen Natur schon lange tun…“ (Emil Fischer, 1915).