TY - JOUR A1 - Ulber, Roland A1 - Tippkötter, Nils A1 - Buchholz, H. A1 - Demmer, W. A1 - Scheper, T. T1 - Innovative Verfahren in der Molkeaufarbeitung zur Gewinnung neuer Produkte JF - Deutsche Milchwirtschaft Y1 - 2008 SN - 0012-0480 VL - 59 IS - 19 SP - 704 EP - 706 ER - TY - CHAP A1 - Frotscher, Ralf A1 - Goßmann, Matthias A1 - Raatschen, Hans-Jürgen A1 - Temiz Artmann, Aysegül A1 - Staat, Manfred T1 - Simulation of cardiac cell-seeded membranes using the edge-based smoothed FEM T2 - Shell and membrane theories in mechanics and biology. (Advanced structured materials ; 45) N2 - We present an electromechanically coupled Finite Element model for cardiac tissue. It bases on the mechanical model for cardiac tissue of Hunter et al. that we couple to the McAllister-Noble-Tsien electrophysiological model of purkinje fibre cells. The corresponding system of ordinary differential equations is implemented on the level of the constitutive equations in a geometrically and physically nonlinear version of the so-called edge-based smoothed FEM for plates. Mechanical material parameters are determined from our own pressure-deflection experimental setup. The main purpose of the model is to further examine the experimental results not only on mechanical but also on electrophysiological level down to ion channel gates. Moreover, we present first drug treatment simulations and validate the model with respect to the experiments. Y1 - 2015 SN - 978-3-319-02534-6 ; 978-3-319-02535-3 SP - 187 EP - 212 PB - Springer CY - Heidelberg ER - TY - CHAP A1 - Engel, M. A1 - Thieringer, J. A1 - Tippkötter, Nils T1 - Microbial electrosynthesis for sustainable biobutanol production T2 - New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany Y1 - 2016 SP - 77 EP - 78 PB - DECHEMA CY - Frankfurt am Main ER - TY - JOUR A1 - Borgmeier, Claudia A1 - Bongaerts, Johannes A1 - Meinhardt, Friedhelm T1 - Genetic analysis of the Bacillus licheniformis degSU operon and the impact of regulatory mutations on protease production JF - Journal of biotechnology N2 - Disruption experiments targeted at the Bacillus licheniformis degSU operon and GFP-reporter analysis provided evidence for promoter activity immediately upstream of degU. pMutin mediated concomitant introduction of the degU32 allele – known to cause hypersecretion in Bacillus subtilis – resulted in a marked increase in protease activity. Application of 5-fluorouracil based counterselection through establishment of a phosphoribosyltransferase deficient Δupp strain eventually facilitated the marker-free introduction of degU32 leading to further protease enhancement achieving levels as for hypersecreting wild strains in which degU was overexpressed. Surprisingly, deletion of rapG – known to interfere with DegU DNA-binding in B. subtilis – did not enhance protease production neither in the wild type nor in the degU32 strain. The combination of degU32 and Δupp counterselection in the type strain is not only equally effective as in hypersecreting wild strains with respect to protease production but furthermore facilitates genetic strain improvement aiming at biological containment and effectiveness of biotechnological processes. KW - Marker-free mutagenesis KW - Extracellular enzymes KW - Uracil-phosphoribosyltransferase KW - Hypersecretion Y1 - 2012 U6 - https://doi.org/10.1016/j.jbiotec.2012.02.011 SN - 1873-4863 (E-Journal); 0168-1656 (Print) VL - 159 IS - 1-2 SP - 12 EP - 20 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Molinnus, Denise A1 - Sorich, Maren A1 - Bartz, Alexander A1 - Siegert, Petra A1 - Willenberg, Holger S. A1 - Lisdat, Fred A1 - Poghossian, Arshak A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Towards an adrenaline biosensor based on substrate recycling amplification in combination with an enzyme logic gate JF - Sensors and Actuators B: Chemical N2 - An amperometric biosensor using a substrate recycling principle was realized for the detection of low adrenaline concentrations (1 nM) by measurements in phosphate buffer and Ringer’s solution at pH 6.5 and pH 7.4, respectively. In proof-of-concept experiments, a Boolean logic-gate principle has been applied to develop a digital adrenaline biosensor based on an enzyme AND logic gate. The obtained results demonstrate that the developed digital biosensor is capable for a rapid qualitative determination of the presence/absence of adrenaline in a YES/NO statement. Such digital biosensor could be used in clinical diagnostics for the control of a correct insertion of a catheter in the adrenal veins during adrenal venous-sampling procedure. Y1 - 2016 U6 - https://doi.org/10.1016/j.snb.2016.06.064 SN - 0925-4005 VL - 237 SP - 190 EP - 195 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bäcker, Matthias A1 - Beging, Stefan A1 - Biselli, Manfred A1 - Poghossian, Arshak A1 - Wang, J. A1 - Zang, Werner A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Concept for a solid-state multi-parameter sensor system for cell-culture monitoring JF - Electrochimica Acta. 54 (2009), H. 25 Sp. Iss. SI Y1 - 2009 SN - 0013-4686 SP - 6107 EP - 6112 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Biselli, Manfred A1 - Bäcker, Matthias A1 - Poghossian, Arshak A1 - Schöning, Michael Josef A1 - Schnitzler, Thomas A1 - Zang, Werner A1 - Wagner, P. T1 - Entwicklung eines modularen festkörperbasierten Sensorsystems für die Überwachung von Zellkulturfermenationen JF - Sensoren und Messsysteme 2010 [Elektronische Ressource] : Vorträge der 15. ITG/GMA-Fachtagung vom 18. bis 19. Mai 2010 in Nürnberg / Informationstechnische Gesellschaft im VDE (ITG); VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA) Y1 - 2010 SN - 978-3-8007-3260-9 N1 - Fachtagung Sensoren und Messsysteme 15, 2010, Nürnberg ; Gesellschaft Mess- und Automatisierungstechnik SP - 688 EP - 691 PB - VDE Verlag CY - Berlin ER - TY - CHAP A1 - Tippkötter, Nils A1 - Schünemann, V. A1 - Christmann, R. A1 - Pasteur, A. A1 - Schweizer, J. A1 - Ulber, Roland ED - Beckmann, Dieter T1 - Bioaffinity Layering magnetisierbarer Mikro- und Nanopartikel T2 - Technische Systeme für die Lebenswissenschaften : 14. Heiligenstädter Kolloquium, Heilbad Heiligenstadt, 22.09. - 24.09.2008 Y1 - 2008 SN - 978-3-00-025695-0 SP - 97 EP - 98 CY - Heiligenstadt ER - TY - JOUR A1 - Huck, Christina A1 - Schiffels, Johannes A1 - Herrera, Cony N. A1 - Schelden, Maximilian A1 - Selmer, Thorsten A1 - Poghossian, Arshak A1 - Baumann, Marcus A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Metabolic responses of Escherichia coli upon glucose pulses captured by a capacitive field-effect sensor JF - Physica Status Solidi (A) N2 - Living cells are complex biological systems transforming metabolites taken up from the surrounding medium. Monitoring the responses of such cells to certain substrate concentrations is a challenging task and offers possibilities to gain insight into the vitality of a community influenced by the growth environment. Cell-based sensors represent a promising platform for monitoring the metabolic activity and thus, the “welfare” of relevant organisms. In the present study, metabolic responses of the model bacterium Escherichia coli in suspension, layered onto a capacitive field-effect structure, were examined to pulses of glucose in the concentration range between 0.05 and 2 mM. It was found that acidification of the surrounding medium takes place immediately after glucose addition and follows Michaelis–Menten kinetic behavior as a function of the glucose concentration. In future, the presented setup can, therefore, be used to study substrate specificities on the enzymatic level and may as well be used to perform investigations of more complex metabolic responses. Conclusions and perspectives highlighting this system are discussed. Y1 - 2013 U6 - https://doi.org/10.1002/pssa.201200900 SN - 0031-8965 VL - 210 IS - 5 SP - 926 EP - 931 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Thiel, Alexander A1 - Tippkötter, Nils A1 - Suck, Kirstin A1 - Sohling, Ulrich A1 - Ruf, Friedrich A1 - Ulber, Roland T1 - New zeolite adsorbents for downstream processing of polyphenols from renewable resources JF - Engineering in Life Sciences N2 - Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources. Y1 - 2013 U6 - https://doi.org/10.1002/elsc.201200188 VL - 13 IS - 3 SP - 239 EP - 246 PB - Wiley CY - Weinheim ER -