Redoxbiochemie des genetischen Codes(S. 748)
Recent research on the quantum chemistry of the amino acids and on the temporal order of their ancient introduction into the genetic code has yielded the surprising finding that the amino acids have become systematically softer (i. a. meaning more redox reactive) during evolution. This trend is recapitulated by recent innovations in organelle genetic codes found in present-day animals. Thus, aspects of chemical reactivity rather than three-dimensional structure optimization governed the finalization of the modern genetic code.
Histonvarianten – Gleiche Gene bedeuten nicht gleiches Schicksal(S. 752)
Ramona M. M. Spitzer, Sandra B. Hake
Chromatin is one of the most significant structures to regulate gene expression. Active deposition and incorporation of specialized histone variants can lead to severe alterations in gene expression, cell cycle progression and embryonic development. Further, deregulation or mutations of histone variants are often implicated in diseases, most notably cancer development. Our work focuses on the discovery of novel human histone variants and variant-interactors to better understand fundamental epi - genetic processes.
Intrazellulär gut vernetzt – das Proteom der chlamydialen Inklusion(S. 756)
Dagmar Heuer, Sebastian Banhart
Chlamydia trachomatis is an important human pathogen with over 130 million new infections per year, world-wide. This obligate intracellular bacterium grows inside a membrane-bound compartment – the inclusion. Recently, using a global approach we were able to comprehensively describe the interactions of the bacterium with cellular proteins. These data indicate the inclusion is an intracellular trafficking hub embedded into the cellular vesicular trafficking pathways. 0);
Wie bakterielle Moleküle unser Immunsystem manipulieren(S. 759)
Minh-Thu Nguyen, Friedrich Götz
Lipoproteins (Lpp) of Gram-positive bacteria play a crucial role in immune modulation. The degree of lipid acylation determines whether the TLR2/TLR1 or the TLR2/TLR6 signalling pathway is induced in the infected host. Both pathways differ significantly in the extent of innate immune activation. Commensal bacteria on our skin signal via the TLR2/TLR1 pathway thus inducing only a mild immune response while non-commensal bacteria signal via TLR2/TLR6 pathway thereby inducing a fulminant immune response. Consequently, the structure of the lipid residue in Lpp decides over immune tolerance or intolerance.
Biogenese und Autophagie des Endoplasmatischen Retikulums(S. 762)
Jasmin Schäfer, Sebastian Schuck
Adaptation to changing physiological conditions requires continuous adjustment of endoplasmic reticulum (ER) capacity. Cells have evolved elegant mechanisms to enlarge and shrink their ER according to need. An ER-localized monitoring system senses insufficient protein folding capacity and activates ER biogenesis to expand the organelle. Furthermore, cells dispose of excess or damaged ER by selective autophagy (ER-phagy). Together, these mechanisms ensure ER homeostasis and proper cell function.
Zirkulierende Tumorzellen – vollautomatisierte Vereinzelung aus Blut(S. 766)
Sabine Alebrand, Christian Freese, Tobias Schunck, Michael Baßler
Circulating tumor cells (CTCs) are interesting for both, cancer diagnostics and therapy. Hence for practical use, very efficient methods are required to enrich, detect and isolate the typically very low number of CTCs. Herein, we present the “CTCelect device”, enabling the fully automated counting and isolation of CTCs from a blood sample for further biological investigations.
Engineering von intrazellulären Modulatoren(S. 769)
Svenja Wiechmann, Andreas Ernst
The engineering of affinity reagents has become a standard technology in modern drug development efforts. High-throughput screening of recombinant protein libraries has yielded numerous affinity reagents that are used in diagnostic or therapeutic applications. In our approach, we engineer intracellular affinity reagents by enhancing pre-existing intermole - cular contacts to target functional epitopes in proteins. The designed affinity reagents allow a fast and specific interrogation of druggable sites in therapeutic relevant proteins.
HDX-MS in den Lebenswissenschaften(S. 772)
Wieland Steinchen, Uwe Linne, Gert Bange
In-depth structural and mechanistic analysis of biomolecular complexes is crucial for modern life sciences. Here we give an overview on hydrogendeuterium exchange mass spectrometry (HDX-MS) as an attractive tool to study the dynamic and structural features of proteins and their complexes.":
Zirkulierende extrazelluläre Vesikelk — die Biomarker der Zukunft?!(S. 777)
Helmut E. Meyer, Fouzi El Magraoui, Gerd Schmitz
Extracellular vesicles (EV) are secreted by most cells and are present in every body fluid. They can be seen as major players in the regulation and communication of cells. They are adressed as therapeutic and diagnostic tool for many disorders including neurodegenerative diseases. Distinct subpopulations of platelet derived EVs have been shown to contain high concentrations of Alzheimer’s disease(AD)-associated proteins e. g. APP, APOE, lipids and miRNAs and thus might contribute actively to the progression of the disease.
Das Mikromilieu beeinflusst das Zellschicksal von Keimzelltumoren(S. 779)
Daniel Nettersheim, Hubert Schorle
Testicular germ cell cancers are subdivided into seminomas and nonseminomas. Here, we summarize how different cellular microenvironments affect the cell fate of seminomas. Further, we describe the molecular mechanisms driving a reprogramming into an embryonal carcinoma (the stem cell population of the non-seminomas) and differentiation into a mixed non-seminoma. Our results may explain how non-seminomas develop that contain a seminoma component, which are often observed in clinical routine.
Bioresponsive Diagnostik – die Zunge als Detektor oraler Entzündungen(S. 782)
Jennifer Ritzer, Tobias Miesler, Lorenz Meinel
The presented diagnostic – a protease cleavable sensor is administered in a chewing gum. Once it comes in contact with patient’s saliva, containing inflammation enzymes, a taste sensation is produced. The patient tastes the presence of inflammation and can tell his doctor about it. The presented diagnostic system can be applied without any power supply anywhere by anybody, at any time – a new dimension of rapid diagnostics.
Anwendungen & Produkte
Antivirales Therapiemonitoring bei Hepatitis C(S. 793)
Ute Hofmann, Beatrix Grey, Ingolf Lachmann
Nucleic acid amplification tests based on real-time PCR are currently regarded as the gold standard of therapy monitoring of both acute and chronic hepatitis C (HCV) infections. In order to monitor the effectiveness of the therapy and the recovery process, a highly sensitive quantitative HCV RNA assay is required. To sustain reliable statements during the entire therapeutic process these assays need to provide precise quantification of viral loads from high-to-weak positive concentrations of HCV RNA as well as a detection limit below 25 IU/ml.
Humanisierung großer Genomabschnitte mittels CRISPR und Recombineering(S. 796)
Martina Reiss, Harald Kranz
Animal models, e. g. transgenic mice, in which the endogenous gene is replaced by a human disease-associated gene variant, are essential tools for biomedical research. While CRISPR/Cas9 has successfully been used to stimulate the integration of small DNA sequences into a target locus such complex genome engineering tasks remain challenging. In this study we combined very large targeting constructs with the potential of the CRISPR/Cas9-mediated double-strand breaks to humanize a 33 kb locus in the mouse.
Tackling the numbers problem: Entwicklung nicht-nativer Enzymreaktionen(S. 830)
Michelle Kammel, Anja Knorrscheidt, Pascal Püllmann, Martin J. Weissenborn
The screening effort of large protein variant libraries renders the probability of coincidental discovering a new enzyme with non-natural activity to almost zero – the so-called numbers problem. Insights into the origin of life, evolution and enzymatic promiscuity, combined with the inspiration of methods from organic chemistry, offer solutions for this problem. With the newly discovered enzymes synthetic micro production units shall be established in a Leibniz Research Cluster where engineering and biotechnology are combined.
Analyse von Präbiotika in Milch: Laktose, Lactulose und Epilactose(S. 833)
Lutz Fischer, Beatrice Kuschel, Ines Seitl, Timo Stressler
Lactulose and epilactose are potentially prebiotic isomers of the milk sugar lactose. Enzymatically they can be produced using cellobiose 2-epimerases. These sugars are notoriously hard to quantify due to their chemical similarity, which results in incomplete separation. With a new commercial stationary phase we achieved baseline separation on a basic HPLC system. The method allows the parallel quantification of lactose, epilactose and lactulose within a wide range of concentrations befitting most food samples.
Enzymdiversität als Basis für die Entwicklung artifizieller Biosynthesen(S. 836)
Bernhard Hauer, Nico Kreß
Biocatalysis can serve as a basis for the synthesis of structurally challenging valuable compounds. The synergistic use of biological and chemical knowledge represents a fruitful approach for finding starting points in the development of novel enzymes. Several enzyme engineering techniques are nowadays available to evolve such starting activities towards tailored enzymes in artificial biochemical syntheses.