Bielefeld, Germany
Bielefeld, Germany

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Wellert S.,TU Berlin | Tiersch B.,University of Potsdam | Koetz J.,University of Potsdam | Richardt A.,Wehrwissenschaftliches Institute For Schutztechnologien Abc Schutz | And 9 more authors.
European Biophysics Journal | Year: 2011

The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris is of great interest because of its ability to catalyze the hydrolysis of highly toxic organophosphates. In this work, the enzyme structure in solution (native state) was studied by use of different scattering methods. The results are compared with those from hydrodynamic model calculations based on the DFPase crystal structure. Bicontinuous microemulsions made of sugar surfactants are discussed as host systems for the DFPase. The microemulsion remains stable in the presence of the enzyme, which is shown by means of scattering experiments. Moreover, activity assays reveal that the DFPase still has high activity in this complex reaction medium. To complement the scattering experiments cryo-SEM was also employed to study the microemulsion structure. © 2011 European Biophysical Societies' Association.


Hennig S.,Universitatsstr 25 | Monkemoller V.,Universitatsstr 25 | Boger C.,Goethe University Frankfurt | Muller M.,Universitatsstr 25 | And 2 more authors.
ACS Nano | Year: 2015

Optical microscopy modalities that achieve spatial resolution beyond the resolution limit have opened up new opportunities in the biomedical sciences to reveal the structure and kinetics of biological processes on the nanoscale. These methods are, however, mostly restricted to fluorescence as contrast mechanism, which limits the ultimate spatial resolution and observation time that can be achieved by photobleaching of the fluorescent probes. Here, we demonstrate that Raman scattering provides a valuable contrast mechanism for optical nanoscopy in the form of super-resolution structured illumination microscopy. We find that nanotags, i.e., gold and silver nanoparticles that are capable of surface-enhanced Raman scattering (SERS), can be imaged with a spatial resolution beyond the diffraction limit in four dimensions alongside and with similar excitation power as fluorescent probes. The highly polarized nature of super-resolution structured illumination microscopy renders these nanotags elliptical in the reconstructed super-resolved images, which enables us to determine their orientation within the sample. The robustness of nanotags against photobleaching allows us to image these particles for unlimited periods of time. We demonstrate this by imaging isolated nanotags in a dense layer of fluorophores, as well as on the surface of and after internalization by osteosarcoma cells, always in the presence of fluorescent probes. Our results show that SERS nanotags have the potential to become highly multiplexed and chemically sensitive optical probes for optical nanoscopy that can replace fluorophores in applications where fluorescence photobleaching is prohibitive for following the evolution of biological processes for extended times. © 2015 American Chemical Society.


Lewinski M.,Bielefeld University | Lewinski M.,Universitatsstr 25 | Hallmann A.,Bielefeld University | Staiger D.,Bielefeld University
Molecular genetics and genomics : MGG | Year: 2016

This study focused on the identification and phylogenetic analysis of glycine-rich RNA binding proteins that contain an RNA recognition motif (RRM)-type RNA binding domain in addition to a region with contiguous glycine residues in representative plant species. In higher plants, glycine-rich proteins with an RRM have met considerable interest as they are responsive to environmental cues and play a role in cold tolerance, pathogen defense, flowering time control, and circadian timekeeping. To identify such RRM containing proteins in plant genomes we developed an RRM profile based on the known glycine-rich RRM containing proteins in the reference plant Arabidopsis thaliana. The application of this remodeled RRM profile that omitted sequences from non-plant species reduced the noise when searching plant genomes for RRM proteins compared to a search performed with the known RRM_1 profile. Furthermore, we developed an island scoring function to identify regions with contiguous glycine residues, using a sliding window approach. This approach tags regions in a protein sequence with a high content of the same amino acid, and repetitive structures score higher. This definition of repetitive structures in a fixed sequence length provided a new glance for characterizing patterns which cannot be easily described as regular expressions. By combining the profile-based domain search for well-conserved regions (the RRM) with a scoring technique for regions with repetitive residues we identified groups of proteins related to the A. thaliana glycine-rich RNA binding proteins in eight plant species.


Nematollahzadeh A.,TU Dortmund | Nematollahzadeh A.,University of Mohaghegh | Lindemann P.,TU Dortmund | Sun W.,TU Dortmund | And 4 more authors.
Journal of Chromatography A | Year: 2014

In the present work, we report a novel method for the reinforcement of hierarchically structured molecularly imprinted polymer (MIP) for the separation of human serum albumin (HSA) and immunoglobulin G (IgG) proteins under pressure driven flow conditions. The template proteins (HSA or IgG) were first physically adsorbed at their isoelectric point on the surface of wide pore silica particles. Thereafter, the pore system was filled with a monomer solution and polymerized to form a lightly crosslinked polyacrylamide network covering the protein template. In order to enhance the rigidity of the hydrogels, different type of crosslinkers such as ethylene glycol dimethacrylate (EGDMA), 3,4-dihydroxyphenethylamine (DA) and methylene-bis-acrylamide (MBA), at least partially interpenetrated into the initially made acrylamide base hydrogel leading to formation of an interpenetrating polymer network (IPN). Then the silica matrix was removed to leave highly porous and reinforced MIP. TGA together with FT-IR and TEM analysis supported the interpenetration of the secondary crosslinkers in the initially formed polymer matrix. The compression property of the modified hydrogels as a function of degree of swelling was in the following order: DA. >. EGDMA. >. MBA-IPN-modified hydrogel. Batch binding assay verified the capability of the IPN modified MIPs to capture the target proteins. Moreover, solid phase extraction, HPLC and SDS-PAGE revealed that the EGDMA modified MIP could selectively capture and separate the proteins from human serum or fermentation broth. © 2014 Elsevier B.V.


Schwabedissen J.,Universitatsstr 25 | Lane P.D.,University of York | Masters S.L.,University of Canterbury | Hassler K.,University of Graz | Wann D.A.,University of York
Dalton Transactions | Year: 2014

The gas-phase structures of the disilanes 1,1,2,2-tetrakis(trimethylsilyl) disilane [(Me3Si)2HSiSiH(SiMe3)2] (1) and 1,1,2,2-tetrakis(trimethylsilyl)dimethyldisilane [(Me 3Si)2MeSiSiMe(SiMe3)2] (2) have been determined by density functional theoretical calculations and by gas electron diffraction (GED) employing the SARACEN method. For each of 1 and 2 DFT calculations revealed four C2-symmetric conformers occupying minima on the respective potential-energy surfaces; three conformers were estimated to be present in sufficient quantities to be taken into account when fitting the GED data. For (Me3Si)2RSiSiR(SiMe3)2 [R = H (1), CH3 (2)] the lowest energy conformers were found by GED to have RSiSiR dihedral angles of 87.7(17)° for 1 and -47.0(6)° for 2. For each of 1 and 2 the presence of bulky and flexible trimethylsilyl groups dictates many aspects of the geometric structures in the gas phase, with the molecules often adopting structures that reduce steric strain. © 2014 The Royal Society of Chemistry.


Steil J.J.,Universitatsstr 25 | Emmerich C.,Universitatsstr 25 | Swadzba A.,Universitatsstr 25 | Grunberg R.,Universitatsstr 25 | And 2 more authors.
Springer Tracts in Advanced Robotics | Year: 2014

The presented work approaches programming of redundant robots such as the KUKA Lightweight Robot IV in a co-worker scenario from a user-centered point of view. It specifically asks, how the user’s implicit knowledge about the scene and the task can be transferred effectively to the robot through kinesthetic teaching. It proposes a new method to visualize the implicit scene model conveyed by the user when teaching a respective inverse kinematics and measures generalization by the robot. Based on these insights and empirical results from a previously performed user study, the present study argues that physical guidance of a task in confined spaces with static obstacles is too difficult to achieve in a single interaction. Summarizing earlier results and putting them into context, it is shown how to assist users to remedy this issue. The key is to divide the process in an explicit configuration phase for teaching the implicit scene model and a subsequent already assisted programming phase to teach the task based on a particular assisted gravity compensation mode. Further results from the user study confirm that this renders kinesthetic teaching in confined spaces feasible and enables a flexible and fast reconfiguration of the robot. © Springer International Publishing Switzerland 2014.


Einecke N.,Honda Research Institute Europe | Muhlig M.,Honda Research Institute Europe | Muhlig M.,Universitatsstr 25 | Schmudderich J.,Honda Research Institute Europe | Gienger M.,Honda Research Institute Europe
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2011

Humanoid robots are intended to act and interact in dynamically changing environments in the presence of humans. Current robotic systems are usually able to move in dynamically changing environments because of an inbuilt depth and obstacle sensing. However, for acting in their environment the internal representation of such systems is usually constructed by hand and known in advance. In contrast, this paper presents a system that dynamically constructs its internal scene representation using a model-based vision approach. This enables our system to approach and grasp objects in an previously unknown scene. We combine standard stereo with model-based image fitting techniques for a real-time estimation of the position and orientation of objects. The model-based image processing allows for an easy transfer to the internal, dynamic scene representation. For movement generation we use a task-level whole-body control approach that is coupled with a movement optimization scheme. Furthermore, we present a novel method that constrains the robot to keep certain objects in the FOV while moving. We demonstrate the successful interplay between model-based vision, dynamic scene representation, and movement generation by means of some interactive reaching and grasping tasks. © 2011 IEEE.


Background: Germany currently does not yet have a nationwide drowning prevention strategy. In addition, there is no statistical reporting regarding fatal cases of drowning and non-fatal cases of near-drowning. Several hundreds of fatal drowning cases and a presumably several times higher unknown number of non-fatal cases of near-drowning occur every year in Germany. Thus, there is unquestionably room for improvement concerning statistics on drowning and near-drowning.Method and results: Based on an analysis of existing drowning statistics in Germany the authors recommend the implementation of a web-based German drowning database providing information about fatal cases of drowning and non-fatal cases of near-drowning.Conclusion: The implementation of a German drowning database via Internet can vastly enhance knowledge about drowning in Germany. Information specifically pertaining to non-fatal cases of near-drowning can be significantly improved. The background and details of these cases would provide better quality information. © 2014, Springer-Verlag Berlin Heidelberg.

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