Einblicke in die Kinderstube der Ribosomen(S. 144)
Jochen Baßler, Ed Hurt
Ribosome formation can be imagined like an assembly line for automobile production. Pre-ribosomes transit through a number of ‘mounting-stages’. These different steps are catalyzed by about 200 assembly factors that bind transiently to the evolving ribosome. However, it currently remains unclear how this myriad of factors can trigger ribosome synthesis. Insight into the mechanism of ribosome biogenesis also has medical relevance, since there are diseases in which ribosome assembly is disturbed.
Rekonstitution biologischer Selbstorganisation in vitro(S. 148)
Simon Kretschmer, Petra Schwille
The Escherichia coli Min proteins select the cell middle for division by oscillating between the cell poles where they inhibit the divisome protein FtsZ. Reconstitution of Min proteins on a lipid membrane in vitro yields their self-organization into surface waves. In biomimetic compartments, pole-to-pole oscillations can be obtained which direct FtsZ to the middle. This establishes bottom-up synthetic biology as a promising approach to reconstitute complex dynamics and spatial cues in vitro.
Knöllchensymbiose – wenn Pflanzen und Bakterien sich verstehen(S. 151)
Rhizobia are a diverse group of bacteria engaged in nitrogen-fixing symbioses with leguminous plants. A prevalent interaction type results in root nodules colonized by the bacteria. Establishment and maintenance of this symbiosis involves specific recognition and coordinated differentiation of both bacterial and host cells driven by signal exchange. Characterization of this interplay reveals an impressive degree of specificity and fine-tuning resulting from million years of evolution.
Die Amerikanische Faulbrut, eine ernsthafte Bedrohung der Honigbiene(S. 154)
American foulbrood is one of the most devastating honey bee diseases. Although the causative agent, Paenibacillus larvae, only kills larval stages, diseased colonies will eventually die from the lack of progeny. Analysis of P. larvae virulence mechanisms revealed that P. larvae has evolved means to combat microbial competitors, expresses an enzyme able to degrade the peritrophic matrix (a chitin-containing protective layer lining the midgut epithelium), and uses toxins and an S-layer protein to attack and breach the midgut epithelium thereby killing the larva.
Pupylierung – ein bakterielles Pendant zur Ubiquitinylierung(S. 158)
Andreas Küberl, Tino Polen, Michael Bott
Pupylation is a reversible process in which the prokaryotic ubiquitin-like protein Pup is attached to target proteins by an isopeptide bond. It occurs mainly in Actinobacteria and was discovered in Mycobacterium tuberculosis, where pupylated proteins are targeted for proteasomal degradation, thus resembling ubiquitination in eukaryotes. Interestingly, species without a proteasome like Corynebacterium glutamicum also perform pupylation. Key features of this protein modification are summarized here.
Strukturelle Evolution des Signalerkennungspartikels(S. 161)
Georg Kempf, Klemens Wild, Irmgard Sinning
The signal recognition particle (SRP) is a ribonucleoprotein complex, which plays a central role in the first steps of membrane protein and secretory protein biogenesis. It recognizes nascent polypeptides at the ribosome by an N-terminal signal sequence and guides them to the translocation channel in the membrane of the endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes. Here, we focus on recent structural insights highlighting the SRP RNA as a dynamic module and on evolutionary aspects of RNA to protein transitions.
Fluorosomen werfen Licht auf Ribosomenproduktion(S. 164)
Elke Deuerling, Rainer Nikolay
Ribosomes facilitate protein biosynthesis in all living cells. They consist of two subunits composed of protein and RNA constituents. Ribosome biogenesis is insufficiently explored due to its complexity and, at the same time, supposed to be an attractive target for new antimicrobials. For both scientific and pharmaceutical purposes the use of fluorescently labeled ribosomes (fluorosomes) could be a valuable tool.
3D-Zellkulturmodelle auf Basis thermogeformter Polymerfolien(S. 169)
Eric Gottwald, Stefan Giselbrecht, Roman Truckenmüller
For more than 100 years tissue culture has relied on two-dimensional platforms, such as petri dishes and derivatives thereof, although for more than already 50 years it is known that three dimensional (3D) culture methods lead to or improve the organotypic behavior of cells. We have developed a new method to generate uniform cellular 3D aggregates with a defined position by means of thermoformed thin polymer films containing “microcavities” making them an useful system for a multitude of applications in which 3D is of prime importance.
In vitro-Hauttestsysteme zur Untersuchung lichtassoziierter Hautschädigung(S. 172)
Sibylle Thude, Petra J. Kluger, Katja Schenke-Layland
Sunlight has various effects on human health. Several important meta - bolic processes are only enabled by sunlight. But longtime sun bathing and extended outdoor activities can cause skin irritation, inflammation or even skin cancer due to high radiation dose. We developed in vitro skin models of different complexity to investigate UV-light associated skin damage. Substances and their phototoxic, sun protective or photo-sensitizing potential can be analyzed to prevent white skin cancer.
Mikrofluidisches 3D-Zellkulturmodell der Blut-Hirn-Schranke(S. 175)
Heiko Kiessling, Ingo Schulz, Eleonore Haltner, Gert Fricker, Martin Stelzle, Julia Schütte
State of the art animal and cell culture models fail to predict the ability of drugs to cross the blood-brain barrier as they lack comparability to the complex human situation. The development of novel pharmaceutics therefore requires in vitro models with human like cell response. Therefore, we are developing a model which mimics the organ environment including the specific 3D arrangement of different cell types, extracellular matrix, and perfusion by combining biology, biochemistry and micro - fluidic technology.
Anwendungen & Produkte
Methoden zur Transportercharakterisierung in primären Hepatozyten(S. 188)
Markus Keiser, Jia Jia, Werner Siegmund, Anett Ullrich, Dieter Runge
Primary mammalian hepatocytes are used for several in vitro applications like drug metabolism and toxicity assays. The influence of substances on uptake and efflux transporters has to be evaluated during development as well. Therefore, we characterized the uptake and the efflux transport of different substrates in appropriate hepatocytes of different species.
Methoden zur RNA-Detektion in lebenden Zellen(S. 191)
Don Weldon, Martin J. Stoddart
RNA plays a key regulatory role in cell and tissue development and disease progression. Various detection methods are available to study RNA, but many require cell lysis, which causes significant information loss. This article will describe different RNA detection methods and highlight the challenges and benefits of detecting RNA in live cells. It will then describe a method that allows for live-cell RNA detection within individual cells, illustrating its use in current research.
3D-Sphäroidkulturen für die onkologische Wirkstoffforschung(S. 194)
Salvatore Alamia, Heiko van der Kuip, Rainer Heller, Ulrike Honisch
Although 2D cell cultures are still predominant in high-throughput drug screening, they may not accurately represent a native in vivo environment, potentially contributing to high attrition in drug development. Implementation of 3D spheroid cultures is now regarded as a better rationale to generate more predictive in vitro assays. Microplates equipped with a surface to prevent cell attachment present an ideal platform for 3D cultures, compatible with high-throughput spheroid cultivation.
Tierische Proteinhydrolysate als N-Quelle für die Milchsäurefermentation(S. 228)
Boris Winter, Axel Höhling, Joachim Venus
Polylactic acid, a biodegradable polymer, is an ecological alternative for petroleum-derived plastics. The biotechnological production of its precursor lactic acid demands complex carbon and nitrogen sources significantly defining the fermentation costs. Whereas a variety of waste streams have already been utilized as carbon providing substrates, there is still no cheap alternative for common peptones. Protein hydrolyzates from animal by-products could be a promising solution to fill this gap.
Eine Roboterplattform für das Hochdurchsatz-Screening von Biokatalysatoren(S. 230)
Uwe Bornscheuer, Mark Dörr, Dominique Böttcher, Anke Hummel, Matthias Höhne
We have established an automated robotic platform to perform all steps required for enzyme production and analysis in a microtiter plate format. This system covers colony picking, growth, protein expression, enzyme isolation and in-depth biochemical characterization using spectrophotometric and fluorimetric assays. It has successfully been applied to screen mutant libraries of biocatalysts for e.g., substrate scope, enantioselectivity or stability for various enzyme classes such as transaminases, Baeyer- Villiger monoxygenases, esterases and dehalogenases.
Karriere, Köpfe & Konzepte
Vernetzung von Bioinformatik-Infrastrukturen in Deutschland(S. 236)
Mit einem neuen Großprojekt im Umfang von mehr als 22 Millionen Euro startet das Bundesministerium für Bildung und Forschung (BMBF) ab März dieses Jahres ein fünfjähriges Vorhaben zur Vernetzung der Bioinformatik- Infrastruktur in Deutschland. Das Deutsche Netzwerk für Bioinformatik- Infrastruktur (de.NBI) wurde zunächst für drei Jahre bewilligt. Das BMBF-Großprojekt geht auf eine Empfehlung des Bioökonomierates aus dem Jahr 2012  zurück.