@article{MuschallikMolinnusBongaertsetal.2017, author = {Muschallik, Lukas and Molinnus, Denise and Bongaerts, Johannes and Pohl, Martina and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Siegert, Petra and Selmer, Thorsten}, title = {(R,R)-Butane-2,3-diol Dehydrogenase from Bacillus clausii DSM 8716T: Cloning and Expression of the bdhA-Gene, and Initial Characterization of Enzyme}, series = {Journal of Biotechnology}, volume = {258}, journal = {Journal of Biotechnology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2017.07.020}, pages = {41 -- 50}, year = {2017}, abstract = {The gene encoding a putative (R,R)-butane-2,3-diol dehydrogenase (bdhA) from Bacillus clausii DSM 8716T was isolated, sequenced and expressed in Escherichia coli. The amino acid sequence of the encoded protein is only distantly related to previously studied enzymes (identity 33-43\%) and exhibited some uncharted peculiarities. An N-terminally StrepII-tagged enzyme variant was purified and initially characterized. The isolated enzyme catalyzed the (R)-specific oxidation of (R,R)- and meso-butane-2,3-diol to (R)- and (S)-acetoin with specific activities of 12 U/mg and 23 U/mg, respectively. Likewise, racemic acetoin was reduced with a specific activity of up to 115 U/mg yielding a mixture of (R,R)- and meso-butane-2,3-diol, while the enzyme reduced butane-2,3-dione (Vmax 74 U/mg) solely to (R,R)-butane-2,3-diol via (R)-acetoin. For these reactions only activity with the co-substrates NADH/NAD+ was observed. The enzyme accepted a selection of vicinal diketones, α-hydroxy ketones and vicinal diols as alternative substrates. Although the physiological function of the enzyme in B. clausii remains elusive, the data presented herein clearly demonstrates that the encoded enzyme is a genuine (R,R)-butane-2,3-diol dehydrogenase with potential for applications in biocatalysis and sensor development.}, language = {en} } @article{MolinnusMuschallikGonzalezetal.2018, author = {Molinnus, Denise and Muschallik, Lukas and Gonzalez, Laura Osorio and Bongaerts, Johannes and Wagner, Torsten and Selmer, Thorsten and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Development and characterization of a field-effect biosensor for the detection of acetoin}, series = {Biosensors and Bioelectronics}, volume = {115}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.bios.2018.05.023}, pages = {1 -- 6}, year = {2018}, abstract = {A capacitive electrolyte-insulator-semiconductor (EIS) field-effect biosensor for acetoin detection has been presented for the first time. The EIS sensor consists of a layer structure of Al/p-Si/SiO₂/Ta₂O₅/enzyme acetoin reductase. The enzyme, also referred to as butane-2,3-diol dehydrogenase from B. clausii DSM 8716T, has been recently characterized. The enzyme catalyzes the (R)-specific reduction of racemic acetoin to (R,R)- and meso-butane-2,3-diol, respectively. Two different enzyme immobilization strategies (cross-linking by using glutaraldehyde and adsorption) have been studied. Typical biosensor parameters such as optimal pH working range, sensitivity, hysteresis, linear concentration range and long-term stability have been examined by means of constant-capacitance (ConCap) mode measurements. Furthermore, preliminary experiments have been successfully carried out for the detection of acetoin in diluted white wine samples.}, language = {en} } @article{MiyamotoSekiSutoetal.2018, author = {Miyamoto, Koichiro and Seki, Kosuke and Suto, Takeyuki and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers}, series = {Sensor and Actuators B: Chemical}, volume = {273}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2018.07.016}, pages = {1328 -- 1333}, year = {2018}, abstract = {The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.}, language = {en} } @article{MiyamotoYuIsodaetal.2016, author = {Miyamoto, Ko-ichiro and Yu, Bing and Isoda, Hiroko and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Visualization of the recovery process of defects in a cultured cell layer by chemical imaging sensor}, series = {Sensors and Actuators B: Chemical}, volume = {236}, journal = {Sensors and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2016.04.018}, pages = {965 -- 969}, year = {2016}, abstract = {The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) in the sample. In this study, a novel cell assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the recovery of defects in a cell layer brought into proximity of the sensing surface. A reduced impedance at a defect formed artificially in a cell layer was successfully visualized in a photocurrent image. The cell layer was cultured over two weeks, during which the temporal change of the photocurrent distribution corresponding to the recovery of the defect was observed.}, language = {de} } @article{MiyamotoYoshidaSakaietal.2011, author = {Miyamoto, Ko-ichiro and Yoshida, Midori and Sakai, Taito and Matsuzaka, Atsushi and Wagner, Torsten and Kanoh, Sanoh and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {Differential setup of light-addressable potentiometric sensor with an enzyme reactor in a flow channel}, series = {Japanese Journal of Applied Physics. 50 (2011)}, journal = {Japanese Journal of Applied Physics. 50 (2011)}, publisher = {Japan Society of Applied Physics}, address = {Bristol}, isbn = {0021-4922}, pages = {04DL08-1 -- 04DL08-5}, year = {2011}, language = {en} } @article{MiyamotoWagnerYoshinobuetal.2011, author = {Miyamoto, Ko-ichiro and Wagner, Torsten and Yoshinobu, Tatsuo and Kanoh, Shin`ichiro and Sch{\"o}ning, Michael Josef}, title = {Phase-mode LAPS and its application to chemical imaging}, series = {Sensors and Actuators B: Chemical. 154 (2011), H. 1}, journal = {Sensors and Actuators B: Chemical. 154 (2011), H. 1}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1873-3077}, pages = {28 -- 32}, year = {2011}, language = {en} } @article{MiyamotoWagnerYoshinobuetal.2011, author = {Miyamoto, Ko-ichiro and Wagner, Torsten and Yoshinobu, Tatsuo and Kanoh, Shin`ichiro and Sch{\"o}ning, Michael Josef}, title = {Phase-mode operation of FDM-LAPS}, series = {Sensor letters}, volume = {9}, journal = {Sensor letters}, number = {2}, publisher = {American Scientific Publishers}, address = {Stevenson Ranch, Calif.}, isbn = {1546-1971}, pages = {691 -- 694}, year = {2011}, language = {en} } @article{MiyamotoWagnerMimuraetal.2011, author = {Miyamoto, Ko-ichiro and Wagner, Torsten and Mimura, Shuhei and Kanoh, Shin{\´i}chiro and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {Constant-phase-mode operation of the light-addressable potentiometric sensor}, series = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, journal = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1873-3077}, pages = {119 -- 123}, year = {2011}, language = {en} } @article{MiyamotoWagnerMimuraetal.2009, author = {Miyamoto, Ko-ichiro and Wagner, Torsten and Mimura, Shuhei and Kanoh, Shin`ichiro and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {Constant-phase-mode operation of the light-addressable potentiometric sensor}, series = {Procedia Chemistry. 1 (2009), H. 1}, journal = {Procedia Chemistry. 1 (2009), H. 1}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1876-6196}, pages = {1487 -- 1490}, year = {2009}, language = {en} } @inproceedings{MiyamotoSutoWerneretal.2017, author = {Miyamoto, Ko-ichiro and Suto, Takeyuki and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Restraining the Diffusion of Photocarriers to Improve the Spatial Resolution of the Chemical Imaging Sensor}, series = {MDPI Proceedings}, volume = {1}, booktitle = {MDPI Proceedings}, number = {4}, doi = {10.3390/proceedings1040477}, pages = {4 Seiten}, year = {2017}, language = {en} }