Detection of mRNA using the BIACORE

We present the detection of native mRNA using the BIACORE system. The influence of different probes and flow rates on the detection is shown and compared to the hybridisation of oligonucleotides. Probes for mRNA detection were chosen by calculations of secondary structures using energy minimizing criteria based on the algorithm of Zuker. Probe concentrations were optimised as well as the regeneration conditions for the sensor surface. The influence of the flow rate appeared to be more marked for mRNA than for oligonucleotide hybridisation

Circular economy inspired imaginaries for sustainable innovations

In this chapter, Narayan and Tidström draw on the concept of imaginaries to show how Circular Economy (CE) can facilitate values that enable sustainable innovation. Innovation is key for sustainability, however, understanding and implementing sustainable innovation is challenging, and identifying the kind of actions that could direct sustainable innovations is important. The findings of this study indicate that CE-inspired imaginaries enable collaboration and by relating such imaginaries to common and shared social and cultural values, intermediaries could motivate actors into taking actions that contribute to sustainable innovation.fi=vertaisarvioitu|en=peerReviewed

Thermodynamische und kinetische Isotopieeffekte am System Paladium-Deuterium/Wasserstoff Untersuchungen mit Hilfe elektrochemischer Verfahren

SIGLEAvailable from the library of Muenster Univ. (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Application of atomic force microscopy and grating coupler for the characterization of biosensor surfaces

Atomic force microscopy (AFM) and an optical grating coupler system were used to improve the understanding of the biosensing layer on a Ta2O5-light-guiding surface. Exemplary, we investigated the immobilization of the protein avidin, the subsequent binding of biotinylated oligonucleotides and hybridization of a complementary 12-mer. The AFM measurements revealed the height of -1.6 nm for a single avidin molecule, while the thickness of the avidin layer on the biosensor surface seemed to be 2.8-3.0 nm. This result lead to the conclusion that the protein was not forming a simple monolayer. However, the thickness of the avidin layer could not be determined directly, but only after shifting of protein by the tip of the AFM leading to grooves of 1 μm2 and -3 nm depth. As the height of oxide particles forming the waveguide surface was also in the range of 1.5 nm, the depth of these grooves could also be a result of the deposition of proteins on top of the oxide particles. This was consistent with the increased roughness of the surface after protein binding. Thus, investigations with the grating coupler were used to determine quantitatively the amount of immobilized avidin. On a biotinylated surface the amount of immobilized avidin lead to the assumption of a complete monolayer, whereas simple adsorption proved to be less efficient. A binding ratio of 1:1.3 for avidin and a biotinylated oligonucleotide was achieved. Up to 83% of the bound single strand were accessible for a subsequent hybridization reaction with a 12-mer. These results supported the model of avidin being deposited mainly on top of the oxide particles leading to the picture of a 'rough' complete protein monolayer, which was postulated from the AFM investigations

Biophysical characterization of E. coli TolC interaction with the known blocker hexaamminecobalt

Background The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. Methods We utilized single channel electrophysiology measurements for studying TolC conductance in the absence and presence of the known TolC blocker hexaamminecobalt. Association and dissociation constants of hexaamminecobalt were determined using surface plasmon resonance measurements. Minimum inhibitory concentration (MIC) assays in the absence and presence of antibiotics were carried out for investigating the antibacterial effect of hexaamminecobalt and its potential to reduce MICs. Results TolC gating in the absence of any ligand is voltage dependent and asymmetric at high applied voltages. Hexaamminecobalt binds to TolC with high affinity and kinetic data revealed fast association and dissociation rates. Despite potent binding to TolC, hexaamminecobalt does not possess an intrinsic antimicrobial activity against E. coli nor does it reduce MIC values of antibiotics erythromycin and fusidic acid. Conclusions TolC opening can be effectively blocked by small molecules. More potent channel blockers are needed in order to investigate the eligibility of TolC as drug target. General significance TolC, a potentially interesting pharmaceutical target can be addressed by small molecules, blocking the channel. Biophysical characterization of the binding processes will support future identification and optimisation of more potent TolC blockers in order to validate TolC as a pharmaceutical target