@article{BechtSchollmayerMonakhovaetal.2021, author = {Becht, Alexander and Schollmayer, Curd and Monakhova, Yulia and Holzgrabe, Ulrike}, title = {Tracing the origin of paracetamol tablets by near-infrared, mid-infrared, and nuclear magnetic resonance spectroscopy using principal component analysis and linear discriminant analysis}, series = {Analytical and Bioanalytical Chemistry}, volume = {413}, journal = {Analytical and Bioanalytical Chemistry}, publisher = {Springer Nature}, issn = {1618-2650}, doi = {10.1007/s00216-021-03249-z}, pages = {3107 -- 3118}, year = {2021}, abstract = {Most drugs are no longer produced in their own countries by the pharmaceutical companies, but by contract manufacturers or at manufacturing sites in countries that can produce more cheaply. This not only makes it difficult to trace them back but also leaves room for criminal organizations to fake them unnoticed. For these reasons, it is becoming increasingly difficult to determine the exact origin of drugs. The goal of this work was to investigate how exactly this is possible by using different spectroscopic methods like nuclear magnetic resonance and near- and mid-infrared spectroscopy in combination with multivariate data analysis. As an example, 56 out of 64 different paracetamol preparations, collected from 19 countries around the world, were chosen to investigate whether it is possible to determine the pharmaceutical company, manufacturing site, or country of origin. By means of suitable pre-processing of the spectra and the different information contained in each method, principal component analysis was able to evaluate manufacturing relationships between individual companies and to differentiate between production sites or formulations. Linear discriminant analysis showed different results depending on the spectral method and purpose. For all spectroscopic methods, it was found that the classification of the preparations to their manufacturer achieves better results than the classification to their pharmaceutical company. The best results were obtained with nuclear magnetic resonance and near-infrared data, with 94.6\%/99.6\% and 98.7/100\% of the spectra of the preparations correctly assigned to their pharmaceutical company or manufacturer.}, language = {en} } @article{LindnerBurgerRutledgeetal.2022, author = {Lindner, Simon and Burger, Ren{\´e} and Rutledge, Douglas N. and Do, Xuan Tung and Rumpf, Jessica and Diehl, Bernd W. K. and Schulze, Margit and Monakhova, Yulia}, title = {Is the calibration transfer of multivariate calibration models between high- and low-field NMR instruments possible? A case study of lignin molecular weight}, series = {Analytical chemistry}, volume = {94}, journal = {Analytical chemistry}, number = {9}, publisher = {ACS Publications}, address = {Washington, DC}, isbn = {1520-6882}, doi = {10.1021/acs.analchem.1c05125}, pages = {3997 -- 4004}, year = {2022}, abstract = {Although several successful applications of benchtop nuclear magnetic resonance (NMR) spectroscopy in quantitative mixture analysis exist, the possibility of calibration transfer remains mostly unexplored, especially between high- and low-field NMR. This study investigates for the first time the calibration transfer of partial least squares regressions [weight average molecular weight (Mw) of lignin] between high-field (600 MHz) NMR and benchtop NMR devices (43 and 60 MHz). For the transfer, piecewise direct standardization, calibration transfer based on canonical correlation analysis, and transfer via the extreme learning machine auto-encoder method are employed. Despite the immense resolution difference between high-field and low-field NMR instruments, the results demonstrate that the calibration transfer from high- to low-field is feasible in the case of a physical property, namely, the molecular weight, achieving validation errors close to the original calibration (down to only 1.2 times higher root mean square errors). These results introduce new perspectives for applications of benchtop NMR, in which existing calibrations from expensive high-field instruments can be transferred to cheaper benchtop instruments to economize.}, language = {en} } @article{AboulnagaZouSelmeretal.2018, author = {Aboulnaga, Elhussiny A. and Zou, Huibin and Selmer, Thorsten and Xian, Mo}, title = {Development of a plasmid-based, tunable, tolC-derived expression system for application in Cupriavidus necator H16}, series = {Journal of Biotechnology}, volume = {274}, journal = {Journal of Biotechnology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2018.03.007}, pages = {15 -- 27}, year = {2018}, abstract = {Cupriavidus necator H16 gains increasing attention in microbial research and biotechnological application due to its diverse metabolic features. Here we present a tightly controlled gene expression system for C. necator including the pBBR1-vector that contains hybrid promoters originating from C. necator native tolC-promoter in combination with a synthetic tetO-operator. The expression of the reporter gene from these plasmids relies on the addition of the exogenous inducer doxycycline (dc). The novel expression system offers a combination of advantageous features as; (i) high and dose-dependent recombinant protein production, (ii) tight control with a high dynamic range (On/Off ratio), which makes it applicable for harmful pathways or for toxic protein production, (iii) comparable cheap inducer (doxycycline, dc), (iv) effective at low inducer concentration, that makes it useful for large scale application, (v) rapid, diffusion controlled induction, and (vi) the inducer does not interfere within the cell metabolism. As applications of the expression system in C. necator H16, the growth ability on glycerol was enhanced by constitutively expressing the E. coli glpk gene-encoding for glycerol kinase. Likewise, we used the system to overcome the expression toxicity of mevalonate pathway in C. necator H16. With this system, the mevalonate-genes were successfully introduced in the host and the recombinant strains could produce about 200 mg/l mevalonate.}, language = {en} } @article{KruegerGroetzingerBerndt1987, author = {Kr{\"u}ger, G{\"o}tz and Gr{\"o}tzinger, Joachim and Berndt, Heinz}, title = {Enantiomeric resolution of amino acid derivatives on chiral stationary phases by high-performance liquid chromatography}, series = {Journal of Chromatography A}, volume = {1987}, journal = {Journal of Chromatography A}, number = {397}, issn = {0021-9673}, doi = {10.1016/S0021-9673(01)85005-6}, pages = {223 -- 232}, year = {1987}, language = {en} } @article{NokiharaBerndt1978, author = {Nokihara, Kiyoshi and Berndt, Heinz}, title = {Synthesis of hapten-polypeptide conjugates as antigen models for the N-terminal region of the α-2-chain of rabbit skin collagen}, series = {Journal of the Royal Society of Chemistry: Perkin Transactions 1}, volume = {1978}, journal = {Journal of the Royal Society of Chemistry: Perkin Transactions 1}, number = {3}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1364-5463}, doi = {10.1039/P19780000260}, pages = {260 -- 263}, year = {1978}, abstract = {Synthesis of derivatives of the peptide sequence L-pyroglutamyl-L-phenylalanyl-L-aspartyl-glycyl-L-lysyl-glycyl-glycyl-glycine as the antigenic determinant representing the N-terminal non-helical region of the α-2-chain of rabbit skin collagen, and conjugation to two different polypeptide carriers, are described.}, language = {en} } @article{ScheerKapelyukhRodeetal.2012, author = {Scheer, Nico and Kapelyukh, Yury and Rode, Anja and Buechel, Sandra and Wolf, C. Roland}, title = {Generation and characterization of novel cytochrome P450 Cyp2c gene cluster knockout and CYP2C9 humanized mouse lines}, series = {Molecular Pharmacology}, volume = {82}, journal = {Molecular Pharmacology}, number = {6}, publisher = {ASPET}, address = {Bethesda, Md.}, issn = {1521-0111}, doi = {10.1124/mol.112.080036}, pages = {1022 -- 1029}, year = {2012}, abstract = {Compared with rodents and many other animal species, the human cytochrome P450 (P450) Cyp2c gene cluster varies significantly in the multiplicity of functional genes and in the substrate specificity of its enzymes. As a consequence, the use of wild-type animal models to predict the role of human CYP2C enzymes in drug metabolism and drug-drug interactions is limited. Within the human CYP2C cluster CYP2C9 is of particular importance, because it is one of the most abundant P450 enzymes in human liver, and it is involved in the metabolism of a wide variety of important drugs and environmental chemicals. To investigate the in vivo functions of cytochrome P450 Cyp2c genes and to establish a model for studying the functions of CYP2C9 in vivo, we have generated a mouse model with a deletion of the murine Cyp2c gene cluster and a corresponding humanized model expressing CYP2C9 specifically in the liver. Despite the high number of functional genes in the mouse Cyp2c cluster and the reported roles of some of these proteins in different biological processes, mice deleted for Cyp2c genes were viable and fertile but showed certain phenotypic alterations in the liver. The expression of CYP2C9 in the liver also resulted in viable animals active in the metabolism and disposition of a number of CYP2C9 substrates. These mouse lines provide a powerful tool for studying the role of Cyp2c genes and of CYP2C9 in particular in drug disposition and as a factor in drug-drug interaction.}, language = {en} } @article{BerndtKrueger1985, author = {Berndt, Heinz and Kr{\"u}ger, G{\"o}tz}, title = {Resolution of enantiomeric amino acid derivatives by high-performance liquid chromatography on chiral stationary phases}, series = {Journal of chromatography A}, volume = {1985}, journal = {Journal of chromatography A}, number = {348}, issn = {0021-9673}, doi = {10.1016/S0021-9673(01)92461-6}, pages = {275 -- 279}, year = {1985}, language = {en} } @article{KuropkaMuellerHoeckeretal.1989, author = {Kuropka, Rolf and M{\"u}ller, Bettina and H{\"o}cker, Hartwig and Berndt, Heinz}, title = {Chiral stationary phases via hydrosilylation reaction of N-acryloylamino acids : I. Stationary phase with one chiral centre for high-performance liquid chromatography and development of a new derivatization pattern for amino acid enantiomers}, series = {Journal of chromatography A}, journal = {Journal of chromatography A}, number = {481}, isbn = {0021-9673}, pages = {380 -- 386}, year = {1989}, language = {en} } @article{NokiharaBerndt1978, author = {Nokihara, Kiyoshi and Berndt, Heinz}, title = {Studies on sulfur-containing peptides : tert-butyloxycarbonylsulfenyl and benzyloxycarbonylsulfenyl derivatives as protecting groups for cysteine}, series = {The journal of organic chemistry}, volume = {43}, journal = {The journal of organic chemistry}, number = {25}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo00419a046}, pages = {4893 -- 4895}, year = {1978}, language = {en} } @article{KalbeHoeckerBerndt1989, author = {Kalbe, Jochen and H{\"o}cker, Hartwig and Berndt, Heinz}, title = {Design of enzyme reactors as chromatographic columns for racemic resolution of amino acid esters}, series = {Chromatographia}, volume = {28}, journal = {Chromatographia}, number = {3-4}, isbn = {0009-5893}, doi = {10.1007/BF02319646}, pages = {193 -- 196}, year = {1989}, language = {en} } @article{DanhoNaithaniSasakietal.1980, author = {Danho, Waleed and Naithani, Vinod K. and Sasaki, Andr{\´e} N. and F{\"o}hles, Joseph and Berndt, Heinz and B{\"u}llesbach, Erika E. and Zahn, H.}, title = {Human proinsulin, VII : synthesis of two protected peptides corresponding to the sequences 1—45 and 46—86 of the prohormone}, series = {Hoppe-Seyler's Zeitschrift f{\"u}r physiologische Chemie}, volume = {361}, journal = {Hoppe-Seyler's Zeitschrift f{\"u}r physiologische Chemie}, number = {1}, issn = {1437-4315}, doi = {10.1515/bchm2.1980.361.1.857}, pages = {857 -- 863}, year = {1980}, language = {en} } @article{KalbeKuropkaMeyerStorketal.1988, author = {Kalbe, Jochen and Kuropka, Rolf and Meyer-Stork, L. Sebastian and Berndt, Heinz and Sauter, Sybille L. and Loss, Peter and Hendo, Karsten and Riesner, Detlev and H{\"o}cker, Hartwig}, title = {Isolation and characterization of high-molecular mass DNA from hair shafts}, series = {Biological chemistry}, volume = {369}, journal = {Biological chemistry}, number = {1}, isbn = {0177-3593}, doi = {10.1515/bchm3.1988.369.1.413}, pages = {413 -- 416}, year = {1988}, language = {en} } @article{BaumannTillmannAletsee1989, author = {Baumann, Marcus and Tillmann, Urban and Aletsee, Ludwig}, title = {Distribution of Carbon Among Photosynthetic End Products in the Bloom-Forming Arctic Diatom Thalassiosira antarctica COMBER / Tillmann, U. ; Baumann, M.E.M. ; Aletsee, L.}, series = {Polar Biology. 10 (1989), H. 3}, journal = {Polar Biology. 10 (1989), H. 3}, isbn = {0722-4060}, pages = {231 -- 238}, year = {1989}, language = {en} } @article{RibitschHeumannKarletal.2012, author = {Ribitsch, Doris and Heumann, Sonja and Karl, Wolfgang and Gerlach, Jochen and Leber, Regina and Birner-Gruenberger, Ruth and Gruber, Karl and Eiteljoerg, Inge and Remler, Peter and Siegert, Petra and Lange, Jennifer and Maurer, Karl-Heinz and Berg, Gabriele and Guebitz, G. M. and Schwab, H.}, title = {Extracellular serine proteases from Stenotrophomonas maltophilia: Screening, isolation and heterologous expression in E. coli}, series = {Journal of biotechnology}, volume = {157}, journal = {Journal of biotechnology}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4863 (E-Journal); 0168-1656 (Print)}, doi = {10.1016/j.jbiotec.2011.09.025}, pages = {140 -- 147}, year = {2012}, abstract = {A large strain collection comprising antagonistic bacteria was screened for novel detergent proteases. Several strains displayed protease activity on agar plates containing skim milk but were inactive in liquid media. Encapsulation of cells in alginate beads induced protease production. Stenotrophomonas maltophilia emerged as best performer under washing conditions. For identification of wash-active proteases, four extracellular serine proteases called StmPr1, StmPr2, StmPr3 and StmPr4 were cloned. StmPr2 and StmPr4 were sufficiently overexpressed in E. coli. Expression of StmPr1 and StmPr3 resulted in unprocessed, insoluble protein. Truncation of most of the C-terminal domain which has been identified by enzyme modeling succeeded in expression of soluble, active StmPr1 but failed in case of StmPr3. From laundry application tests StmPr2 turned out to be a highly wash-active protease at 45 °C. Specific activity of StmPr2 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 17 ± 2 U/mg. In addition we determined the kinetic parameters and cleavage preferences of protease StmPr2.}, language = {en} } @article{SrivastavaSinghAggarwaletal.2010, author = {Srivastava, Alok and Singh, Virendra and Aggarwal, Pranav and Schneeweiss, F. and Scherer, Ulrich W. and Friedrich, W.}, title = {Optical studies of insulating polymers for radiation dose monitoring}, series = {Indian Journal of Pure and Applied Physics}, volume = {48}, journal = {Indian Journal of Pure and Applied Physics}, number = {11}, publisher = {Council Of Scientific And Industrial Research (CSIR), National Institute Of Science Communication and Policy Research (NIScPR)}, address = {New Delhi}, isbn = {0019-5596}, pages = {782 -- 786}, year = {2010}, abstract = {The optical study carried out on insulating polymers namely polyethyleneterephthalate (PET) and polyvinylchloride (PVC) has been described. The polymers are exposed to different radiation doses by exposing them to swift heavy ions of carbon (90 MeV), silicon (120 MeV) and nickel (100 MeV) which influence on their optical properties. The studies show that amongst the investigated polymers, PVC and PET have potential for application as dosimeter beyond a threshold dose which is strongly dependent on the nature of the material and the radiation type. The optical micrographs show a distinct change in colour of the sample with increase in radiation dose.}, language = {en} } @article{OehlenschlaegerVolkmarStiefelmaieretal.2024, author = {Oehlenschl{\"a}ger, Katharina and Volkmar, Marianne and Stiefelmaier, Judith and Langsdorf, Alexander and Holtmann, Dirk and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {New insights into the influence of pre-culture on robust solvent production of C. acetobutylicum}, series = {Applied Microbiology and Biotechnology}, volume = {108}, journal = {Applied Microbiology and Biotechnology}, publisher = {Springer}, address = {Berlin, Heidelberg}, issn = {1432-0614}, doi = {10.1007/s00253-023-12981-8}, pages = {10 Seiten}, year = {2024}, abstract = {Clostridia are known for their solvent production, especially the production of butanol. Concerning the projected depletion of fossil fuels, this is of great interest. The cultivation of clostridia is known to be challenging, and it is difficult to achieve reproducible results and robust processes. However, existing publications usually concentrate on the cultivation conditions of the main culture. In this paper, the influence of cryo-conservation and pre-culture on growth and solvent production in the resulting main cultivation are examined. A protocol was developed that leads to reproducible cultivations of Clostridium acetobutylicum. Detailed investigation of the cell conservation in cryo-cultures ensured reliable cell growth in the pre-culture. Moreover, a reason for the acid crash in the main culture was found, based on the cultivation conditions of the pre-culture. The critical parameter to avoid the acid crash and accomplish the shift to the solventogenesis of clostridia is the metabolic phase in which the cells of the pre-culture were at the time of inoculation of the main culture; this depends on the cultivation time of the pre-culture. Using cells from the exponential growth phase to inoculate the main culture leads to an acid crash. To achieve the solventogenic phase with butanol production, the inoculum should consist of older cells which are in the stationary growth phase. Considering these parameters, which affect the entire cultivation process, reproducible results and reliable solvent production are ensured.}, language = {en} } @article{HengsbachEngelCwienczeketal.2023, author = {Hengsbach, Jan-Niklas and Engel, Mareike and Cwienczek, Marcel and Stiefelmaier, Judith and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Scalable unseparated bioelectrochemical reactors by using a carbon fiber brush as stirrer and working electrode}, series = {ChemElectroChem}, volume = {10}, journal = {ChemElectroChem}, number = {21}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2196-0216}, doi = {10.1002/celc.202300440}, pages = {9 Seiten}, year = {2023}, abstract = {The concept of energy conversion into platform chemicals using bioelectrochemical systems (BES) has gained increasing attention in recent years, as the technology simultaneously provides an opportunity for sustainable chemical production and tackles the challenge of Power-to-X technologies. There are many approaches to realize the industrial scale of BES. One concept is to equip standard bioreactors with static electrodes. However, large installations resulted in a negative influence on various reactor parameters. In this study, we present a new single-chamber BES based on a stirred tank reactor in which the stirrer was replaced by a carbon fiber brush, performing the functions of the working electrode and the stirrer. The reactor is characterized in abiotic studies and electro-fermentations with Clostridium acetobutylicum. Compared to standard reactors an increase in butanol production of 20.14±3.66 \% shows that the new BES can be efficiently used for bioelectrochemical processes.}, language = {en} } @article{HaegerProbstJaegeretal.2023, author = {Haeger, Gerrit and Probst, Johanna and Jaeger, Karl-Erich and Bongaerts, Johannes and Siegert, Petra}, title = {Novel aminoacylases from Streptomyces griseus DSM 40236 and their recombinant production in Streptomyces lividans}, series = {FEBS Open Bio}, volume = {13}, journal = {FEBS Open Bio}, number = {12}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2211-5463}, doi = {10.1002/2211-5463.13723}, pages = {2224 -- 2238}, year = {2023}, abstract = {Amino acid-based surfactants are valuable compounds for cosmetic formulations. The chemical synthesis of acyl-amino acids is conventionally performed by the Schotten-Baumann reaction using fatty acyl chlorides, but aminoacylases have also been investigated for use in biocatalytic synthesis with free fatty acids. Aminoacylases and their properties are diverse; they belong to different peptidase families and show differences in substrate specificity and biocatalytic potential. Bacterial aminoacylases capable of synthesis have been isolated from Burkholderia, Mycolicibacterium, and Streptomyces. Although several proteases and peptidases from S. griseus have been described, no aminoacylases from this species have been identified yet. In this study, we investigated two novel enzymes produced by S. griseus DSM 40236ᵀ . We identified and cloned the respective genes and recombinantly expressed an α-aminoacylase (EC 3.5.1.14), designated SgAA, and an ε-lysine acylase (EC 3.5.1.17), designated SgELA, in S. lividans TK23. The purified aminoacylase SgAA was biochemically characterized, focusing on its hydrolytic activity to determine temperature- and pH optima and stabilities. The aminoacylase could hydrolyze various acetyl-amino acids at the Nα -position with a broad specificity regarding the sidechain. Substrates with longer acyl chains, like lauroyl-amino acids, were hydrolyzed to a lesser extent. Purified aminoacylase SgELA specific for the hydrolysis of Nε -acetyl-L-lysine was unstable and lost its enzymatic activity upon storage for a longer period but could initially be characterized. The pH optimum of SgELA was pH 8.0. While synthesis of acyl-amino acids was not observed with SgELA, SgAA catalyzed the synthesis of lauroyl-methionine.}, language = {en} } @article{WeldenSeverinsPoghossianetal.2022, author = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Bongaerts, Johannes and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor}, series = {Chemosensors}, volume = {10}, journal = {Chemosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2227-9040}, doi = {10.3390/chemosensors10060218}, pages = {Artikel 218}, year = {2022}, abstract = {Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte-insulator-semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin-streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage-current, capacitance-voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution.}, language = {en} } @article{WeldenJablonskiWegeetal.2021, author = {Welden, Rene and Jablonski, Melanie and Wege, Christina and Keusgen, Michael and Wagner, Patrick Hermann and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase}, series = {Biosensors}, volume = {11}, journal = {Biosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2079-6374}, doi = {10.3390/bios11060171}, pages = {Artikel 171}, year = {2021}, abstract = {The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte's pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.}, language = {en} }