Degraded Arabinogalactans and Their Binding Properties to Cancer-Associated Human Galectins

Galectins represent β-galactoside-binding proteins with numerous functions. Due to their role in tumor progression, human galectins-1, -3 and -7 (Gal-1, -3 and -7) are potential targets for cancer therapy. As plant derived glycans might act as galectin inhibitors, we prepared galactans by partial degradation of plant arabinogalactan-proteins. Besides commercially purchased galectins, we produced Gal-1 and -7 in a cell free system and tested binding capacities of the galectins to the galactans by biolayer-interferometry. Results for commercial and cell-free expressed galectins were comparable confirming functionality of the cell-free produced galectins. Our results revealed that galactans from Echinacea purpurea bind to Gal-1 and -7 with KD values of 1-2 µM and to Gal-3 slightly stronger with KD values between 0.36 and 0.70 µM depending on the sensor type. Galactans from the seagrass Zostera marina with higher branching of the galactan and higher content of uronic acids showed stronger binding to Gal-3 (0.08-0.28 µM) compared to galactan from Echinacea. The results contribute to knowledge on interactions between plant polysaccharides and galectins. Arabinogalactan-proteins have been identified as a new source for production of galactans with possible capability to act as galectin inhibitors

Erfahrungen, Herausforderungen und Lösungsansätze aus der Extraktion pseudonymer Daten für das Projekt INDEED

Background: In Germany there is currently no health reporting on cross-sectoral care patterns in the context of an emergency department care treatment. The INDEED project (Utilization and trans-sectoral patterns of care for patients admitted to emergency departments in Germany) collects routine data from 16 emergency departments, which are later merged with outpatient billing data from 2014 to 2017 on an individual level. Aim: The methodological challenges in planning of the internal merging of routine clinical and administrative data from emergency departments in Germany up to the final data extraction are presented together with possible solution approaches. Methods: Data were selected in an iterative process according to the research questions, medical relevance, and assumed data availability. After a preparatory phase to clarify formalities (including data protection, ethics), review test data and correct if necessary, the encrypted and pseudonymous data extraction was performed. Results: Data from the 16 cooperating emergency departments came mostly from the emergency department and hospital information systems. There was considerable heterogeneity in the data. Not all variables were available in every emergency department because, for example, they were not standardized and digitally available or the extraction effort was judged to be too high. Conclusion: Relevant data from emergency departments are stored in different structures and in several IT systems. Thus, the creation of a harmonized data set requires considerable resources on the part of the hospital as well as the data processing unit. This needs to be generously calculated for future projects

Challenges of Regulatory Environmental Risk Assessment for Human Pharmaceuticals with Focus on Antibiotics

Just recently the problem of pharmaceutical residues in the environment has been emphasized by OECD. Especially antibiotics are of concern due to their widespread use and diverse modes of actions including ones that can affect the photosynthetic activity of primary producers and subsequently primary biomass production and carbon dioxide fixation. The EU regulatory authority, the European Medicines Agency (EMA), has therefore proposed to implement a new tailored environmental risk assessment scheme, published in a new draft guideline 2018. Threshold effect levels to three fixed representative species of green algae and cyanobacteria will be required. This article reviews and compares the contamination of waters with antibiotics in Switzerland and Germany and also presents an overview of published effect data on eukaryotic algae and prokaryotic cyanobacteria in order to discuss the representativeness of the selected species. Since no full datasets as demanded by the EMA were publically available yet, the gaps for four antibiotics have been experimentally completed. In summary the results support the species selection of the EMA published in the revised draft guideline, however it remains unclear whether diatoms should also be considered

Zellfreie Protein-Produktion zur Target- und Substrat-Evaluation

Für die Entwicklung neuartiger Antibiotika stellt die Target-Identifizierung einen kritischen Schritt in der Entdeckung neuartiger Antibiotika dar. Für die Target-Identifizierung von Antibiotika steht unter anderem die zellfreie Proteinsynthese zur Verfügung. Weiterhin findet die zellfreie Proteinsynthese Anwendung für die Synthese von Membranproteinen. Von besonderem Interesse im Kontext der Membranproteine ist die Identifizierung neuer Substrate. Eine neuartige Hochdurchsatz-Methode, stellt die Bio-Layer-Interferometrie (BLI) dar. Eine Nutzung der BLI zum Substrat-Screening für Membranproteine würde eine neue Anwendung schaffen. In dieser Arbeit werden zwei verschiedene Fragestellungen angegangen. Einerseits wird ein effektives zellfreies in vitro Screening-System für Inhibitoren der bakteriellen Ribosomenaktivität mit direkter Fluoreszenzmessung beschrieben. Die Fluorophorbildung des grün fluoreszierenden Proteins oder des monomeren NeonGreen erfolgt innerhalb einer Stunde und benötigt ein geringes Volumen. Zum Zweiten wird in dieser Arbeit für die Etablierung der BLI als Substrat-Screening-Methode ein Testsystem eingeführt. Hier wurden die beiden Aquaglyceroporine Plasmodium falciparum (PfAQP1) sowie die Isoform 2 aus Trypanosoma brucei (TbAQP2) zellfrei synthetisiert und in Liposomen rekonstituiert. Die Funktionalität der Liposomen wurde anhand einer Charakterisung des Schrumpf- und Schwellverhalten gegenüber verschiedenen hyperosmotischen Zuckeralkoholen an der stopped flow-Methode gezeigt

Synthesis and Solid-State Organization of Coil-Ring-Coil Block Copolymers

Shape-persistent macrocycles based on the phenyl-ethynyl-butadienyl backbone containing two extraannular hydroxyl groups were prepared by the oxidative coupling of the appropriate phenylethynyl oligomers. Carbodiimide-directed coupling with independently synthesized polystyrene carboxylic acid oligomers led to ABA coil-ring-coil block copolymers in which the central macrocycle serves as rigid and the polystyrene oligomers as flexible elements. Depending on the size of the coil blocks, these structures aggregate in cyclohexane into supramolecular hollow cylindrical brushes in which the rigid core is surrounded by the flexible matrix. However, in the solid state it is not possible to identify a morphology in which isolated channels based on aggregated macrocycles are embedded in a matrix of polystyrene. Detailed X-ray and electron diffraction studies on samples prepared from a solution in cyclohexane under equilibrium conditions show that the material adopts a lamellar morphology in the solid state in which columns of macrocycles are aggregated into layers which are separated by polystyrene

Temporal Switching of Homo-FRET Pathways in Single-Chromophore Dimer Models of π-Conjugated Polymers

A set of π-conjugated oligomer dimers templated in molecular scaffolds is presented as a model system for studying the interactions between chromophores in conjugated polymers (CPs). Single-molecule spectroscopy was used to reveal energy transfer dynamics between two oligomers in either a parallel or oblique-angle geometry. In particular, the conformation of single molecules embedded in a host matrix was investigated via polarized excitation and emission fluorescence microscopy in combination with fluorescence correlation spectroscopy. While the intramolecular interchromophore conformation was found to have no impact on the fluorescence quantum yield, lifetime, or photon statistics (antibunching), the long-term nonequilibrium dynamics of energy transfer within these bichromophoric systems was accessible by studying the linear dichroism in emission at the single-molecule level, which revealed reversible switching of the emission between the two oligomers. In bulk polymer films, interchromophore coupling promotes the migration of excitation energy to quenching sites. Realizing the presence and dynamics of such interactions is crucial for understanding limitations on the quantum efficiency of larger CP materials

Switching between H- and J-type electronic coupling in single conjugated polymer aggregates

Coherent coupling in soft matter, controlled by nanoscale morphology, plays an important role in charge generation and recombination in optoelectronics. Eder et al. show how to reversibly switch between H- and J-type coupling in conjugated polymer aggregates, leading to tunable photoluminescence