@misc{SaguTchewonpiHuschekBoenicketal.2019, author = {Sagu Tchewonpi, Sorel and Huschek, Gerd and B{\"o}nick, Josephine and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {A New Approach of Extraction of α-Amylase/trypsin Inhibitors from Wheat (Triticum aestivum L.), Based on Optimization Using Plackett-Burman and Box-Behnken Designs}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {805}, issn = {1866-8372}, doi = {10.25932/publishup-44222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442229}, pages = {20}, year = {2019}, abstract = {Wheat is one of the most consumed foods in the world and unfortunately causes allergic reactions which have important health effects. The α-amylase/trypsin inhibitors (ATIs) have been identified as potentially allergen components of wheat. Due to a lack of data on optimization of ATI extraction, a new wheat ATIs extraction approach combining solvent extraction and selective precipitation is proposed in this work. Two types of wheat cultivars (Triticum aestivum L.), Julius and Ponticus were used and parameters such as solvent type, extraction time, temperature, stirring speed, salt type, salt concentration, buffer pH and centrifugation speed were analyzed using the Plackett-Burman design. Salt concentration, extraction time and pH appeared to have significant effects on the recovery of ATIs (p < 0.01). In both wheat cultivars, Julius and Ponticus, ammonium sulfate substantially reduced protein concentration and inhibition of amylase activity (IAA) compared to sodium chloride. The optimal conditions with desirability levels of 0.94 and 0.91 according to the Doehlert design were: salt concentrations of 1.67 and 1.22 M, extraction times of 53 and 118 min, and pHs of 7.1 and 7.9 for Julius and Ponticus, respectively. The corresponding responses were: protein concentrations of 0.31 and 0.35 mg and IAAs of 91.6 and 83.3\%. Electrophoresis and MALDI-TOF/MS analysis showed that the extracted ATIs masses were between 10 and 20 kDa. Based on the initial LC-MS/MS analysis, up to 10 individual ATIs were identified in the extracted proteins under the optimal conditions. The positive implication of the present study lies in the quick assessment of their content in different varieties especially while considering their allergenic potential.}, language = {en} } @article{SaguTchewonpiHuschekBoenicketal.2019, author = {Sagu Tchewonpi, Sorel and Huschek, Gerd and B{\"o}nick, Josephine and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {A New Approach of Extraction of α-Amylase/trypsin Inhibitors from Wheat (Triticum aestivum L.), Based on Optimization Using Plackett-Burman and Box-Behnken Designs}, series = {molecules}, volume = {24}, journal = {molecules}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules24193589}, pages = {18}, year = {2019}, abstract = {Wheat is one of the most consumed foods in the world and unfortunately causes allergic reactions which have important health effects. The α-amylase/trypsin inhibitors (ATIs) have been identified as potentially allergen components of wheat. Due to a lack of data on optimization of ATI extraction, a new wheat ATIs extraction approach combining solvent extraction and selective precipitation is proposed in this work. Two types of wheat cultivars (Triticum aestivum L.), Julius and Ponticus were used and parameters such as solvent type, extraction time, temperature, stirring speed, salt type, salt concentration, buffer pH and centrifugation speed were analyzed using the Plackett-Burman design. Salt concentration, extraction time and pH appeared to have significant effects on the recovery of ATIs (p < 0.01). In both wheat cultivars, Julius and Ponticus, ammonium sulfate substantially reduced protein concentration and inhibition of amylase activity (IAA) compared to sodium chloride. The optimal conditions with desirability levels of 0.94 and 0.91 according to the Doehlert design were: salt concentrations of 1.67 and 1.22 M, extraction times of 53 and 118 min, and pHs of 7.1 and 7.9 for Julius and Ponticus, respectively. The corresponding responses were: protein concentrations of 0.31 and 0.35 mg and IAAs of 91.6 and 83.3\%. Electrophoresis and MALDI-TOF/MS analysis showed that the extracted ATIs masses were between 10 and 20 kDa. Based on the initial LC-MS/MS analysis, up to 10 individual ATIs were identified in the extracted proteins under the optimal conditions. The positive implication of the present study lies in the quick assessment of their content in different varieties especially while considering their allergenic potential.}, language = {en} } @article{ChmielewskiBaldermannGoetzetal.2018, author = {Chmielewski, Frank M. and Baldermann, Susanne and G{\"o}tz, Klaus Peter and Homann, Thomas and G{\"o}deke, Kristin and Schumacher, Fabian and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Abscisic acid related metabolites in sweet cherry buds (Prunus avium L.)}, series = {Journal of Horticulture}, volume = {5}, journal = {Journal of Horticulture}, number = {1}, issn = {2376-0354}, doi = {10.4172/2376-0354.1000221}, pages = {221}, year = {2018}, abstract = {As our climate changes, plant mechanisms involved for dormancy release become increasingly important for commercial orchards. It is generally believed that abscisic acid (ABA) is a key hormone that responds to various environmental stresses which affects bud dormancy. For this reason, a multi-year study was initiated to obtain data on plant metabolites during winter rest and ontogenetic development in sweet cherry buds (Prunus avium L.). In this paper, we report on metabolites involved in ABA synthesis and catabolism and its effect on bud dormancy in the years 2014/15-2016/17. In previous work, the timings of the different phases of para-, endo-, ecodormancy and ontogenetic development for cherry flower buds of the cultivar 'Summit' were determined, based on classical climate chamber experiments and changes in the bud's water content. Based on these time phases, we focused now on the different aspects of the ABA-metabolism. The results show that there is a continual synthesis of ABA about 5 weeks before leaf fall, and a degradation of ABA during ecodormancy and bud development until the phenological stage 'open cluster'. This is confirmed by relating the ABA content to that of the total precursor carotenoids, neoxanthin and violaxanthin. The tentative monitoring of individual intermediate metabolites revealed that dihydroxyphaseic acid is the most abundant catabolite of ABA and ABA glucosyl ester is in terms of mass intensity, the most abundant ABA metabolite observed in this study. The results suggest that the direct route for ABA biosynthesis from farnesyl pyrophosphate may also be relevant in cherry flower buds.}, language = {de} } @article{GoetzChmielewskiGoedekeetal.2017, author = {Goetz, Klaus-Peter and Chmielewski, Frank M. and Goedeke, Kristin and Wolf, Kristine and Jander, Elisabeth and Sievers, Steven and Homann, Thomas and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Assessment of amino acids during winter rest and ontogenetic development in sweet cherry buds (Prunus avium. L.)}, series = {Scientia horticulturae : an international journal sponsored by the International Society for Horticultural Science}, volume = {222}, journal = {Scientia horticulturae : an international journal sponsored by the International Society for Horticultural Science}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-4238}, doi = {10.1016/j.scienta.2017.05.001}, pages = {102 -- 110}, year = {2017}, abstract = {This study examined changes in sweet cherry buds of 'Summit' cultivar in four seasons (2011/12-2014/15) with respect to the nitrogen (N) content and the profile of eight free amino acids (asparagine (Asn), aspartic acid (Asp), isoleucine (Ile), glutamine (Gln), glutamic acid (Glu), arginine (Arg), alanine (Ala), histidine (His)). The presented results are to our knowledge the first under natural conditions in fruit tree orchards with a high temporal resolution from the dormant stage until cluster development. The N content in the buds from October, during endo- and ecodormancy until the beginning of ontogenetic development was a relatively stable parameter in each of the four seasons. The N accumulation into the buds began after 'swollen bud' and significant differences were visible at 'green tip' with an N content of 3.24, 3.12, 3.08, 2.40 which increased markedly to the mean of 'tight' and 'open cluster' by 3.77\%, 3.78\%, 3.44\% and 3.10\% in 2012-2015, respectively. In the buds, levels of asparagine were higher (up to 44 mg g\&\#8722;1 DW\&\#8722;1) than aspartic acid (up to 2 mg g\&\#8722;1 DW\&\#8722;1) and aspartic acid higher than isoleucine (up to 0.83 mg g\&\#8722;1 DW\&\#8722;1). Levels of glutamine were higher (up to 25 mg g\&\#8722;1 DW\&\#8722;1) than glutamic acid (up to 20 mg g\&\#8722;1 DW\&\#8722;1). The course of the arginine content was higher in 2011/12 compared to 2012/13, 2013/14 and 2014/15 which showed only slight differences. The alanine content in the buds was denoted in the four seasons only by relatively minor changes. The histidine content was higher in 2011/12 and 2012/13 compared to 2013/14 and 2014/15 which showed a comparable pattern. For 6 amino acids (Asn, Asp, Ile, Glu, Arg, Ala), the highest content was observed in 2012/13, the warmest period between swollen bud and open cluster. However in 2014/15, the season with the lowest mean temperature of 8.8 °C, only the content of Gln was the lowest. It was not possible to explain any seasonal differences in the amino acid content by environmental factors (air temperature) on the basis of few seasons. From none of the measured free amino acids could a clear determination of the date of endodormancy release (t1) or the beginning of the ontogenetic development (t1*) be derived. Therefore, these amino acids are no suitable markers to improve phenological models for the beginning of cherry blossom.}, language = {en} } @article{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep37346}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time-and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @misc{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103674}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @article{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep37346}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @article{AliHomannKreiseletal.2012, author = {Ali, Mostafa and Homann, Thomas and Kreisel, Janka and Khalil, Mahmoud and Puhlmann, Ralf and Kruse, Hans-Peter and Rawel, Harshadrai Manilal}, title = {Characterization and modeling of the interactions between coffee storage proteins and phenolic compounds}, series = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, volume = {60}, journal = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, number = {46}, publisher = {American Chemical Society}, address = {Washington}, issn = {0021-8561}, doi = {10.1021/jf303372a}, pages = {11601 -- 11608}, year = {2012}, abstract = {This study addresses the interactions of coffee storage proteins with coffee-specific phenolic compounds. Protein profiles, of Coffea arabica and Coffea canephora (var robusta) were compared. Major Phenolic compounds were extracted and analyzed with appropriate methods. The polyphenol-protein interactions during protein extraction have been addressed by different analytical setups [reversed-phase high-performance liquid chromatography (RP-HPLC), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS), and Trolox equivalent antioxidant capacity (TEAC) assays], with focus directed toward identification of covalent adduct formation. The results indicate that C. arabica proteins are more susceptible to these interactions and the polyphenol oxidase activity seems to be a crucial factor for the formation of these addition products. A tentative allocation of the modification type and site in the protein has been attempted. Thus, the first available in silico modeling of modified coffee proteins is reported. The extent of these modifications may contribute to the structure and function of "coffee melanoidins" and are discussed in the context of coffee flavor formation.}, language = {en} } @article{RawelHuschekSaguTchewonpietal.2019, author = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas}, title = {Cocoa Bean Proteins}, series = {Nutrients}, volume = {11}, journal = {Nutrients}, number = {2}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {2072-6643}, doi = {10.3390/nu11020428}, pages = {20}, year = {2019}, abstract = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The "state of the art" suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.}, language = {en} } @misc{RawelHuschekSaguTchewonpietal.2019, author = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas}, title = {Cocoa Bean Proteins}, series = {Postprints der Universit{\"a}t Potsdam: Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam: Mathematisch-Naturwissenschaftliche Reihe}, number = {681}, issn = {1866-8372}, doi = {10.25932/publishup-42595}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425953}, pages = {20}, year = {2019}, abstract = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The "state of the art" suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.}, language = {en} } @misc{RawelHuschekSaguTchewonpietal.2019, author = {Rawel, Harshadrai Manilal and Huschek, Gerd and Sagu Tchewonpi, Sorel and Homann, Thomas}, title = {Cocoa Bean Proteins-Characterization, Changes and Modifications due to Ripening and Post-Harvest Processing}, series = {Nutrients}, volume = {11}, journal = {Nutrients}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2072-6643}, doi = {10.3390/nu11020428}, pages = {20}, year = {2019}, abstract = {The protein fractions of cocoa have been implicated influencing both the bioactive potential and sensory properties of cocoa and cocoa products. The objective of the present review is to show the impact of different stages of cultivation and processing with regard to the changes induced in the protein fractions. Special focus has been laid on the major seed storage proteins throughout the different stages of processing. The study starts with classical introduction of the extraction and the characterization methods used, while addressing classification approaches of cocoa proteins evolved during the timeline. The changes in protein composition during ripening and maturation of cocoa seeds, together with the possible modifications during the post-harvest processing (fermentation, drying, and roasting), have been documented. Finally, the bioactive potential arising directly or indirectly from cocoa proteins has been elucidated. The state of the art suggests that exploration of other potentially bioactive components in cocoa needs to be undertaken, while considering the complexity of reaction products occurring during the roasting phase of the post-harvest processing. Finally, the utilization of partially processed cocoa beans (e.g., fermented, conciliatory thermal treatment) can be recommended, providing a large reservoir of bioactive potentials arising from the protein components that could be instrumented in functionalizing foods.}, language = {en} } @article{SaguTchewonpiZimmermannLandgraeberetal.2020, author = {Sagu Tchewonpi, Sorel and Zimmermann, Lynn and Landgr{\"a}ber, Eva and Homann, Thomas and Huschek, Gerd and {\"O}zpinar, Haydar and Schweigert, Florian J. and Rawel, Harshadrai Manilal}, title = {Comprehensive Characterization and Relative Quantification of α-Amylase/Trypsin Inhibitors from Wheat Cultivars by Targeted HPLC-MS/MS}, series = {Foods}, volume = {9}, journal = {Foods}, number = {10}, publisher = {MDPI}, address = {Basel}, issn = {2304-8158}, doi = {10.3390/foods9101448}, pages = {25}, year = {2020}, abstract = {The α-amylase/trypsin inhibitors (ATIs) are discussed as being responsible for non-celiac wheat sensitivity (NCWS), besides being known as allergenic components for baker's asthma. Different approaches for characterization and quantification including proteomics-based methods for wheat ATIs have been documented. In these studies generally the major ATIs have been addressed. The challenge of current study was then to develop a more comprehensive workflow encompassing all reviewed wheat-ATI entries in UniProt database. To substantially test proof of concept, 46 German and Turkish wheat samples were used. Two extractions systems based on chloroform/methanol mixture (CM) and under buffered denaturing conditions were evaluated. Three aspects were optimized, tryptic digestion, chromatographic separation, and targeted tandem mass spectrometric analysis (HPLC-MS/MS). Preliminary characterization with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) documented the purity of the extracted ATIs with CM mixture and the amylase (60-80\%)/trypsin (10-20\%) inhibition demonstrated the bifunctional activity of ATIs. Thirteen (individual/common) biomarkers were established. Major ATIs (7-34\%) were differently represented in samples. Finally, to our knowledge, the proposed HPLC-MS/MS method allowed for the first time so far the analysis of all 14 reviewed wheat ATI entries reported.}, language = {en} } @misc{SaguTchewonpiZimmermannLandgraeberetal.2020, author = {Sagu Tchewonpi, Sorel and Zimmermann, Lynn and Landgr{\"a}ber, Eva and Homann, Thomas and Huschek, Gerd and {\"O}zpinar, Haydar and Schweigert, Florian J. and Rawel, Harshadrai Manilal}, title = {Comprehensive Characterization and Relative Quantification of α-Amylase/Trypsin Inhibitors from Wheat Cultivars by Targeted HPLC-MS/MS}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1028}, issn = {1866-8372}, doi = {10.25932/publishup-48611}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-486118}, pages = {27}, year = {2020}, abstract = {The α-amylase/trypsin inhibitors (ATIs) are discussed as being responsible for non-celiac wheat sensitivity (NCWS), besides being known as allergenic components for baker's asthma. Different approaches for characterization and quantification including proteomics-based methods for wheat ATIs have been documented. In these studies generally the major ATIs have been addressed. The challenge of current study was then to develop a more comprehensive workflow encompassing all reviewed wheat-ATI entries in UniProt database. To substantially test proof of concept, 46 German and Turkish wheat samples were used. Two extractions systems based on chloroform/methanol mixture (CM) and under buffered denaturing conditions were evaluated. Three aspects were optimized, tryptic digestion, chromatographic separation, and targeted tandem mass spectrometric analysis (HPLC-MS/MS). Preliminary characterization with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) documented the purity of the extracted ATIs with CM mixture and the amylase (60-80\%)/trypsin (10-20\%) inhibition demonstrated the bifunctional activity of ATIs. Thirteen (individual/common) biomarkers were established. Major ATIs (7-34\%) were differently represented in samples. Finally, to our knowledge, the proposed HPLC-MS/MS method allowed for the first time so far the analysis of all 14 reviewed wheat ATI entries reported.}, language = {en} } @misc{SaguTchewonpiHuschekWaldbachBragaetal.2022, author = {Sagu Tchewonpi, Sorel and Huschek, Gerd and Waldbach Braga, Tess and Rackiewicz, Michal and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.)}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8372}, doi = {10.25932/publishup-55928}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-559282}, pages = {1 -- 18}, year = {2022}, abstract = {Wheat alpha-amylase/trypsin inhibitors remain a subject of interest considering the latest findings showing their implication in wheat-related non-celiac sensitivity (NCWS). Understanding their functions in such a disorder is still unclear and for further study, the need for pure ATI molecules is one of the limiting problems. In this work, a simplified approach based on the successive fractionation of ATI extracts by reverse phase and ion exchange chromatography was developed. ATIs were first extracted from wheat flour using a combination of Tris buffer and chloroform/methanol methods. The separation of the extracts on a C18 column generated two main fractions of interest F1 and F2. The response surface methodology with the Doehlert design allowed optimizing the operating parameters of the strong anion exchange chromatography. Finally, the seven major wheat ATIs namely P01083, P17314, P16850, P01085, P16851, P16159, and P83207 were recovered with purity levels (according to the targeted LC-MS/MS analysis) of 98.2 ± 0.7; 98.1 ± 0.8; 97.9 ± 0.5; 95.1 ± 0.8; 98.3 ± 0.4; 96.9 ± 0.5, and 96.2 ± 0.4\%, respectively. MALDI-TOF-MS analysis revealed single peaks in each of the pure fractions and the mass analysis yielded deviations of 0.4, 1.9, 0.1, 0.2, 0.2, 0.9, and 0.1\% between the theoretical and the determined masses of P01083, P17314, P16850, P01085, P16851, P16159, and P83207, respectively. Overall, the study allowed establishing an efficient purification process of the most important wheat ATIs. This paves the way for further in-depth investigation of the ATIs to gain more knowledge related to their involvement in NCWS disease and to allow the absolute quantification in wheat samples.}, language = {en} } @article{SaguTchewonpiHuschekWaldbachBragaetal.2022, author = {Sagu Tchewonpi, Sorel and Huschek, Gerd and Waldbach Braga, Tess and Rackiewicz, Michal and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.)}, series = {Processes : open access journal}, volume = {10}, journal = {Processes : open access journal}, edition = {2}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2227-9717}, doi = {10.3390/pr10020259}, pages = {1 -- 18}, year = {2022}, abstract = {Wheat alpha-amylase/trypsin inhibitors remain a subject of interest considering the latest findings showing their implication in wheat-related non-celiac sensitivity (NCWS). Understanding their functions in such a disorder is still unclear and for further study, the need for pure ATI molecules is one of the limiting problems. In this work, a simplified approach based on the successive fractionation of ATI extracts by reverse phase and ion exchange chromatography was developed. ATIs were first extracted from wheat flour using a combination of Tris buffer and chloroform/methanol methods. The separation of the extracts on a C18 column generated two main fractions of interest F1 and F2. The response surface methodology with the Doehlert design allowed optimizing the operating parameters of the strong anion exchange chromatography. Finally, the seven major wheat ATIs namely P01083, P17314, P16850, P01085, P16851, P16159, and P83207 were recovered with purity levels (according to the targeted LC-MS/MS analysis) of 98.2 ± 0.7; 98.1 ± 0.8; 97.9 ± 0.5; 95.1 ± 0.8; 98.3 ± 0.4; 96.9 ± 0.5, and 96.2 ± 0.4\%, respectively. MALDI-TOF-MS analysis revealed single peaks in each of the pure fractions and the mass analysis yielded deviations of 0.4, 1.9, 0.1, 0.2, 0.2, 0.9, and 0.1\% between the theoretical and the determined masses of P01083, P17314, P16850, P01085, P16851, P16159, and P83207, respectively. Overall, the study allowed establishing an efficient purification process of the most important wheat ATIs. This paves the way for further in-depth investigation of the ATIs to gain more knowledge related to their involvement in NCWS disease and to allow the absolute quantification in wheat samples.}, language = {en} } @article{TchewonpiSaguLandgraeberHenkeletal.2021, author = {Tchewonpi Sagu, Sorel and Landgr{\"a}ber, Eva and Henkel, Ina M. and Huschek, Gerd and Homann, Thomas and Bußler, Sara and Schl{\"u}ter, Oliver K. and Rawel, Harshadrai Manilal}, title = {Effect of cereal α-amylase/trypsin inhibitors on developmental characteristics and abundance of digestive enzymes of mealworm larvae (Tenebrio molitor L.)}, series = {Insects}, volume = {12}, journal = {Insects}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2075-4450}, doi = {10.3390/insects12050454}, pages = {16}, year = {2021}, abstract = {The objective of this work was to investigate the potential effect of cereal α-amylase/trypsin inhibitors (ATIs) on growth parameters and selective digestive enzymes of Tenebrio molitor L. larvae. The approach consisted of feeding the larvae with wheat, sorghum and rice meals containing different levels and composition of α-amylase/trypsin inhibitors. The developmental and biochemical characteristics of the larvae were assessed over feeding periods of 5 h, 5 days and 10 days, and the relative abundance of α-amylase and selected proteases in larvae were determined using liquid chromatography tandem mass spectrometry. Overall, weight gains ranged from 21\% to 42\% after five days of feeding. The larval death rate significantly increased in all groups after 10 days of feeding (p < 0.05), whereas the pupation rate was about 25\% among larvae fed with rice (Oryza sativa L.) and Siyazan/Esperya wheat meals, and only 8\% and 14\% among those fed with Damougari and S35 sorghum meals. As determined using the Lowry method, the protein contents of the sodium phosphate extracts ranged from 7.80 ± 0.09 to 9.42 ± 0.19 mg/mL and those of the ammonium bicarbonate/urea reached 19.78 ± 0.16 to 37.47 ± 1.38 mg/mL. The total protein contents of the larvae according to the Kjeldahl method ranged from 44.0 and 49.9 g/100 g. The relative abundance of α-amylase, CLIP domain-containing serine protease, modular serine protease zymogen and C1 family cathepsin significantly decreased in the larvae, whereas dipeptidylpeptidase I and chymotrypsin increased within the first hours after feeding (p < 0.05). Trypsin content was found to be constant independently of time or feed material. Finally, based on the results we obtained, it was difficult to substantively draw conclusions on the likely effects of meal ATI composition on larval developmental characteristics, but their effects on the digestive enzyme expression remain relevant.}, language = {en} } @misc{TchewonpiSaguLandgraeberHenkeletal.2021, author = {Tchewonpi Sagu, Sorel and Landgr{\"a}ber, Eva and Henkel, Ina M. and Huschek, Gerd and Homann, Thomas and Bußler, Sara and Schl{\"u}ter, Oliver K. and Rawel, Harshadrai Manilal}, title = {Effect of cereal α-amylase/trypsin inhibitors on developmental characteristics and abundance of digestive enzymes of mealworm larvae (Tenebrio molitor L.)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {5}, issn = {1866-8372}, doi = {10.25932/publishup-52092}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-520924}, pages = {18}, year = {2021}, abstract = {The objective of this work was to investigate the potential effect of cereal α-amylase/trypsin inhibitors (ATIs) on growth parameters and selective digestive enzymes of Tenebrio molitor L. larvae. The approach consisted of feeding the larvae with wheat, sorghum and rice meals containing different levels and composition of α-amylase/trypsin inhibitors. The developmental and biochemical characteristics of the larvae were assessed over feeding periods of 5 h, 5 days and 10 days, and the relative abundance of α-amylase and selected proteases in larvae were determined using liquid chromatography tandem mass spectrometry. Overall, weight gains ranged from 21\% to 42\% after five days of feeding. The larval death rate significantly increased in all groups after 10 days of feeding (p < 0.05), whereas the pupation rate was about 25\% among larvae fed with rice (Oryza sativa L.) and Siyazan/Esperya wheat meals, and only 8\% and 14\% among those fed with Damougari and S35 sorghum meals. As determined using the Lowry method, the protein contents of the sodium phosphate extracts ranged from 7.80 ± 0.09 to 9.42 ± 0.19 mg/mL and those of the ammonium bicarbonate/urea reached 19.78 ± 0.16 to 37.47 ± 1.38 mg/mL. The total protein contents of the larvae according to the Kjeldahl method ranged from 44.0 and 49.9 g/100 g. The relative abundance of α-amylase, CLIP domain-containing serine protease, modular serine protease zymogen and C1 family cathepsin significantly decreased in the larvae, whereas dipeptidylpeptidase I and chymotrypsin increased within the first hours after feeding (p < 0.05). Trypsin content was found to be constant independently of time or feed material. Finally, based on the results we obtained, it was difficult to substantively draw conclusions on the likely effects of meal ATI composition on larval developmental characteristics, but their effects on the digestive enzyme expression remain relevant.}, language = {en} } @article{SaguTchewonpiHuschekHomannetal.2021, author = {Sagu Tchewonpi, Sorel and Huschek, Gerd and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {Effect of sample preparation on the detection and quantification of selected nuts allergenic proteins by LC-MS/MS}, series = {Molecules : a journal of synthetic chemistry and natural product chemistry / Molecular Diversity Preservation International}, volume = {26}, journal = {Molecules : a journal of synthetic chemistry and natural product chemistry / Molecular Diversity Preservation International}, number = {15}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules26154698}, pages = {21}, year = {2021}, abstract = {The detection and quantification of nut allergens remains a major challenge. The liquid chroma-tography tandem mass spectrometry (LC-MS/MS) is emerging as one of the most widely used methods, but sample preparation prior to the analysis is still a key issue. The objective of this work was to establish optimized protocols for extraction, tryptic digestion and LC-MS analysis of almond, cashew, hazelnut, peanut, pistachio and walnut samples. Ammonium bicar-bonate/urea extraction (Ambi/urea), SDS buffer extraction (SDS), polyvinylpolypyrroli-done (PVPP) extraction, trichloroacetic acid/acetone extraction (TCA/acetone) and chloro-form/methanol/sodium chloride precipitation (CM/NaCl) as well as the performances of con-ventional tryptic digestion and microwave-assisted breakdown were investigated. Overall, the protein extraction yields ranged from 14.9 ± 0.5 (almond extract from CM/NaCl) to 76.5 ± 1.3\% (hazelnut extract from Ambi/urea). Electrophoretic profiling showed that the SDS extraction method clearly presented a high amount of extracted proteins in the range of 0-15 kDa, 15-35 kDa, 35-70 kDa and 70-250 kDa compared to the other methods. The linearity of the LC-MS methods in the range of 0 to 0.4 µg equivalent defatted nut flour was assessed and recovery of internal standards GWGG and DPLNV(d8)LKPR ranged from 80 to 120\%. The identified bi-omarkers peptides were used to relatively quantifier selected allergenic protein form the inves-tigated nut samples. Considering the overall results, it can be concluded that SDS buffer allows a better protein extraction from almond, peanut and walnut samples while PVPP buffer is more appropriate for cashew, pistachio and hazelnut samples. It was also found that conventional overnight digestion is indicated for cashew, pistachio and hazelnut samples, while microwave assisted tryptic digestion is recommended for almond, hazelnut and peanut extracts.}, language = {en} } @misc{TchewonpiSaguHuschekHomannetal.2021, author = {Tchewonpi Sagu, Sorel and Huschek, Gerd and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {Effect of sample preparation on the detection and quantification of selected nuts allergenic proteins by LC-MS/MS}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {15}, issn = {1866-8372}, doi = {10.25932/publishup-52187}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521871}, pages = {16}, year = {2021}, abstract = {The detection and quantification of nut allergens remains a major challenge. The liquid chroma-tography tandem mass spectrometry (LC-MS/MS) is emerging as one of the most widely used methods, but sample preparation prior to the analysis is still a key issue. The objective of this work was to establish optimized protocols for extraction, tryptic digestion and LC-MS analysis of almond, cashew, hazelnut, peanut, pistachio and walnut samples. Ammonium bicar-bonate/urea extraction (Ambi/urea), SDS buffer extraction (SDS), polyvinylpolypyrroli-done (PVPP) extraction, trichloroacetic acid/acetone extraction (TCA/acetone) and chloro-form/methanol/sodium chloride precipitation (CM/NaCl) as well as the performances of con-ventional tryptic digestion and microwave-assisted breakdown were investigated. Overall, the protein extraction yields ranged from 14.9 ± 0.5 (almond extract from CM/NaCl) to 76.5 ± 1.3\% (hazelnut extract from Ambi/urea). Electrophoretic profiling showed that the SDS extraction method clearly presented a high amount of extracted proteins in the range of 0-15 kDa, 15-35 kDa, 35-70 kDa and 70-250 kDa compared to the other methods. The linearity of the LC-MS methods in the range of 0 to 0.4 µg equivalent defatted nut flour was assessed and recovery of internal standards GWGG and DPLNV(d8)LKPR ranged from 80 to 120\%. The identified bi-omarkers peptides were used to relatively quantifier selected allergenic protein form the inves-tigated nut samples. Considering the overall results, it can be concluded that SDS buffer allows a better protein extraction from almond, peanut and walnut samples while PVPP buffer is more appropriate for cashew, pistachio and hazelnut samples. It was also found that conventional overnight digestion is indicated for cashew, pistachio and hazelnut samples, while microwave assisted tryptic digestion is recommended for almond, hazelnut and peanut extracts.}, language = {en} } @article{NeugartWiesnerReinholdFredeetal.2018, author = {Neugart, Susanne and Wiesner-Reinhold, Melanie and Frede, Katja and Jander, Elisabeth and Homann, Thomas and Rawel, Harshadrai Manilal and Schreiner, Monika and Baldermann, Susanne}, title = {Effect of Solid Biological Waste Compost on the Metabolite Profile of Brassica rapa ssp chinensis}, series = {Frontiers in plant science : FPLS}, volume = {9}, journal = {Frontiers in plant science : FPLS}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2018.00305}, pages = {13}, year = {2018}, abstract = {Large quantities of biological waste are generated at various steps within the food production chain and a great utilization potential for this solid biological waste exists apart from the current main usage for the feedstuff sector. It remains unclear how the usage of biological waste as compost modulates plant metabolites. We investigated the effect of biological waste of the processing of coffee, aronia, and hop added to soil on the plant metabolite profile by means of liquid chromatography in pak choi sprouts. Here we demonstrate that the solid biological waste composts induced specific changes in the metabolite profiles and the changes are depending on the type of the organic residues and its concentration in soil. The targeted analysis of selected plant metabolites, associated with health beneficial properties of the Brassicaceae family, revealed increased concentrations of carotenoids (up to 3.2-fold) and decreased amounts of glucosinolates (up to 4.7-fold) as well as phenolic compounds (up to 1.5-fold).}, language = {en} } @article{FigueroaCamposGKTKruizengaSaguTchewonpietal.2022, author = {Figueroa Campos, Gustavo Adolfo and G. K. T. Kruizenga, Johannes and Sagu Tchewonpi, Sorel and Schwarz, Steffen and Homann, Thomas and Taubert, Andreas and Rawel, Harshadrai Manilal}, title = {Effect of the post-harvest processing on protein modification in green coffee beans by phenolic compounds}, series = {Foods : open access journal}, volume = {11}, journal = {Foods : open access journal}, edition = {2}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2304-8158}, doi = {10.3390/foods11020159}, pages = {19}, year = {2022}, abstract = {The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4-8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma. View Full-Text}, language = {en} } @misc{FigueroaCamposGKTKruizengaSaguTchewonpietal.2022, author = {Figueroa Campos, Gustavo A. and G. K. T. Kruizenga, Johannes and Sagu Tchewonpi, Sorel and Schwarz, Steffen and Homann, Thomas and Taubert, Andreas and Rawel, Harshadrai}, title = {Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, volume = {11}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, edition = {2}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8372}, doi = {10.25932/publishup-55764}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-557643}, pages = {1 -- 19}, year = {2022}, abstract = {The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4-8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma. View Full-Text}, language = {en} } @article{SaguTchewonpiNsoHomannetal.2015, author = {Sagu Tchewonpi, Sorel and Nso, Emmanuel Jong and Homann, Thomas and Kapseu, Cesar and Rawel, Harshadrai Manilal}, title = {Extraction and purification of beta-amylase from stems of Abrus precatorius by three phase partitioning}, series = {Food chemistry}, volume = {183}, journal = {Food chemistry}, publisher = {Elsevier}, address = {Oxford}, issn = {0308-8146}, doi = {10.1016/j.foodchem.2015.03.028}, pages = {144 -- 153}, year = {2015}, abstract = {The stems of Abrus precatorius were used to extract a beta-amylase enriched fraction. A three phase partitioning method and a Doehlert design with 3 variables (ratio of crude extract/t-butanol, the ammonium sulphate saturation and pH) were used. The data was fitted in a second-order polynomial model and the parameters were optimized to enrich beta-amylase. Experimental responses for the modulation were recovery of activity and the purification factor. The optimal conditions were: a ratio of crude extract/t-butanol of 0.87 (v/v), saturation in ammonium sulphate of 49.46\% (w/v) and a pH of 5.2. An activity recovery of 156.2\% and a purification factor of 10.17 were found. The enriched enzyme was identified as a beta-amylase and its molecular weight was 60.1 kDa. K-m and V-max values were 79.37 mg/ml and 5.13 U/ml, respectively and the highest activity was registered at a temperature of 70 degrees C and a pH between 6 and 6.5. A significant stabilization of the beta-amylase was observed up to 65 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{UhrWielandHomannetal.2016, author = {Uhr, Linda and Wieland, Phillis and Homann, Thomas and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Identification and LC-MS/MS-based analyses of technical enzymes in wheat flour and baked products}, series = {European food research and technology : official organ of the EuCheMS, Division of Food Chemistry}, volume = {242}, journal = {European food research and technology : official organ of the EuCheMS, Division of Food Chemistry}, publisher = {Springer}, address = {New York}, issn = {1438-2377}, doi = {10.1007/s00217-015-2536-5}, pages = {247 -- 257}, year = {2016}, abstract = {The use of technical enzymes in bakery industry is necessary for a consistent and good quality of baked products. Since the cultivation of cereals leads to low amounts of endogenous enzymes being present, a need of their commercial alternatives is becoming a routine process in order to meet the consumer quality demands. Targeted quantification proteomics-based methods are necessary for their detection to meet the regulatory criteria. Here, we initially report on the identification of Lipase FE-01, a lipase from fungus Thermomyces lanuginosus, as analyzed by SDS-PAGE, in-Gel digestion, and MALDI-TOF-MS. In further experiments, the focus of the study was directed toward an extensive use and optimization of in-solution enzymatic digestion in combination with LC-MS/MS techniques in identification of specific peptide markers and finally in utilization of the latter in delivering reproducible quantification data for several different technical enzymes (alpha-amylases, xylanase, and lipases from microbial origin) in complex matrices such as baked bread and wheat flour. Two digestion protocols (a fast option using thermocycler program and the well-established overnight method) were tested, and both of these can be successfully applied. The application of isotopically labeled analogs of the MRM targeted peptides as internal standards and the addition of an internal protein standard during the extraction/digestion experiment were compared to determine the optimal quantification algorithm of the recovered enzyme concentrations. Thus, a standardized sensitive LC-MS/MS method could be developed to determine technical enzymes as forthcoming ingredients in the prefabricated food formulations in concentrations lower than 10 ppm.}, language = {en} } @article{ChmielewskiGoetzHomannetal.2017, author = {Chmielewski, Frank M. and G{\"o}tz, Klaus-Peter and Homann, Thomas and Rawel, Harshadrai Manilal}, title = {Identification of Endodormancy Release for Cherries (Prunus Avium L.) by Abscisic Acid and Sugars}, series = {Journal of Horticulture}, volume = {4}, journal = {Journal of Horticulture}, number = {3}, issn = {2376-0354}, doi = {10.4172/2376-0354.1000210}, pages = {9}, year = {2017}, abstract = {In order to develop reliable and physiologically sound models for the plant development in spring, the date of endodormancy release is always a crucial and mostly unknown model parameter. Until present, classical approaches - such as climate chamber experiments - are used to derive this unknown parameter. In these experiments, progressive plant development or significant changes in bud's fresh weight or water content are measurable markers for dormancy release. This study presents an alternative approach, which is based on four well-known metabolites. For 5 seasons (2011/12-2015/16), the content of abscisic acid (ABA) and sugars such as fructose, sucrose and glucose in sweet cherry flower buds (cultivar 'Summit') were weekly analysed between beginning of October and April. These data allow comparing the annual course of these metabolites with the date of endodormancy release, derived from a classical climate chamber experiment, published in a previous study. Results showed that ABA and sucrose are two important metabolites which can help to identify the date of endodormancy release of sweet cherries. On average, ABA content reached a plateau of 5.65 μg g-1 DW-1 during endodormancy, which was maintained for 3-6 weeks. The significant reduction of the ABA content after this period to 4.41 μg g-1 DW-1 on average during ecodormancy was nearly in agreement with the date of endodormancy release of 'Summit' on 28 November (332 DOY). The annual cycle of sucrose, which has a cryoprotective effect during winter, is well comprehensible and showed a close relationship to the annual course of minimum air temperature after leaf fall(r=-0.90). The nearly constant level of sucrose during ecodormancy (21.0 mg g-1 DW-1, 5 yr. mean) did not only allow deriving the date of endodormancy release but can also be helpful to define the beginning of ontogenetic development.}, language = {en} } @article{WeinertWieseRaweletal.2012, author = {Weinert, Christoph H. and Wiese, Stefanie and Rawel, Harshadrai Manilal and Esatbeyoglu, Tuba and Winterhalter, Peter and Homann, Thomas and Kulling, Sabine E.}, title = {Methylation of catechins and procyanidins by rat and human Catechol-O-Methyltransferase metabolite profiling and molecular modeling studies}, series = {Drug metabolism and disposition : the biological fate of chemicals}, volume = {40}, journal = {Drug metabolism and disposition : the biological fate of chemicals}, number = {2}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, address = {Bethesda}, issn = {0090-9556}, doi = {10.1124/dmd.111.041871}, pages = {353 -- 359}, year = {2012}, abstract = {Catechins and procyanidins are major polyphenols in plant-derived foods. Despite intensive studies in recent years, neither their biochemical nor their toxicological properties have been clarified sufficiently. This study aimed to compare the methylation of catechins and procyanidins by the enzyme catechol-O-methyltransferase (COMT) in vitro. We conducted incubations with rat liver cytosol and human placental cytosol including S-adenosyl-L-methionine. The set of substrates comprised the catechins (-)-epicatechin (EC) and (+)catechin (CAT), the procyanidin dimers B1, B2, B3, B4, B5, and B7 as well as procyanidin trimer C1. After extraction, metabolites were analyzed by means of liquid chromatography-electrospray ionizationmass spectrometry and liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry. EC and CAT were converted to two monomethylated metabolites each by human and rat COMT, with the 3'-O-methyl derivatives being consistently the main metabolites. Furthermore, the flavanyl units of procyanidins were methylated consecutively, leading to monomethylated and dimethylated dimeric metabolites as well as monomethylated, dimethylated, and trimethylated C1 metabolites. The methylation status of each flavanyl unit was determined by means of mass spectrometric quinone-methide fragmentation patterns. In addition, molecular modeling studies were performed with the aim to predict the preferred site of methylation and to verify the experimental data. In conclusion, our results indicate that the degree and position of methylation depend clearly on the three-dimensional structure of the entire substrate molecule.}, language = {en} } @article{AliHomannKhaliletal.2013, author = {Ali, Mostafa and Homann, Thomas and Khalil, Mahmoud and Kruse, Hans-Peter and Rawel, Harshadrai Manilal}, title = {Milk whey protein modification by coffee-specific phenolics effect on structural and functional properties}, series = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, volume = {61}, journal = {Journal of agricultural and food chemistry : a publication of the American Chemical Society}, number = {28}, publisher = {American Chemical Society}, address = {Washington}, issn = {0021-8561}, doi = {10.1021/jf402221m}, pages = {6911 -- 6920}, year = {2013}, abstract = {A suitable vehicle for integration of bioactive plant constituents is proposed. It involves modification of proteins using phenolics and applying these for protection of labile constituents. It dissects the noncovalent and covalent interactions of beta-lactoglobulin with coffee-specific phenolics. Alkaline and polyphenol oxidase modulated covalent reactions were compared. Tryptic digestion combined with MALDI-TOF-MS provided tentative allocation of the modification type and site in the protein, and an in silico modeling of modified beta-lactoglobulin is proposed. The modification delivers proteins with enhanced antioxidative properties. Changed structural properties and differences in solubility, surface hydrophobicity, and emulsification were observed. The polyphenol oxidase modulated reaction provides a modified beta-lactoglobulin with a high antioxidative power, is thermally more stable, requires less energy to unfold, and, when emulsified with lutein esters, exhibits their higher stability against UV light. Thus, adaptation of this modification provides an innovative approach for functionalizing proteins and their uses in the food industry.}, language = {en} } @article{ReinkensmeierSteinbrennerHomannetal.2016, author = {Reinkensmeier, Annika and Steinbrenner, Katrin and Homann, Thomas and Bussler, Sara and Rohn, Sascha and Rawel, Harshadrai Manilal}, title = {Monitoring the apple polyphenol oxidase-modulated adduct formation of phenolic and amino compounds}, series = {Food chemistry}, volume = {194}, journal = {Food chemistry}, publisher = {Elsevier}, address = {Oxford}, issn = {0308-8146}, doi = {10.1016/j.foodchem.2015.07.145}, pages = {76 -- 85}, year = {2016}, abstract = {Minimally processed fruit products such as smoothies are increasingly coming into demand. However, they are often combined with dairy ingredients. In this combination, phenolic compounds, polyphenoloxidases, and amino compounds could interact. In this work, a model approach is presented where apple serves as a source for a high polyphenoloxidase activity for modulating the reactions. The polyphenoloxidase activity ranged from 128 to 333 nakt/mL in different apple varieties. From these, 'Braeburn' was found to provide the highest enzymatic activity. The formation and stability of resulting chromogenic conjugates was investigated. The results show that such adducts are not stable and possible degradation mechanisms leading to follow-up products formed are proposed. Finally, apple extracts were used to modify proteins and their functional properties characterized. There were retaining antioxidant properties inherent to phenolic compounds after adduct formation. Consequently, such interactions may also be utilized to improve the textural quality of food products.}, language = {en} } @article{StepanovskaZivkovicEnzmannetal.2020, author = {Stepanovska, Bisera and Zivkovic, Aleksandra and Enzmann, Gaby and Tietz, Silvia and Homann, Thomas and Kleuser, Burkhard and Engelhardt, Britta and Stark, Holger and Huwiler, Andrea}, title = {Morpholino analogues of fingolimod as novel and selective S1P1 ligands with in vivo efficacy in a mouse model of experimental antigen-induced encephalomyelitis}, series = {International journal of molecular sciences}, volume = {21}, journal = {International journal of molecular sciences}, number = {18}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms21186463}, pages = {17}, year = {2020}, abstract = {Multiple sclerosis (MS) is a chronic, inflammatory, autoimmune disease of the central nervous system (CNS) which is associated with lower life expectancy and disability. The experimental antigen-induced encephalomyelitis (EAE) in mice is a useful animal model of MS, which allows exploring the etiopathogenetic mechanisms and testing novel potential therapeutic drugs. A new therapeutic paradigm for the treatment of MS was introduced in 2010 through the sphingosine 1-phosphate (S1P) analogue fingolimod (FTY720, Gilenya(R)), which acts as a functional S1P(1) antagonist on T lymphocytes to deplete these cells from the blood. In this study, we synthesized two novel structures, ST-1893 and ST-1894, which are derived from fingolimod and chemically feature a morpholine ring in the polar head group. These compounds showed a selective S1P(1) activation profile and a sustained S1P(1) internalization in cultures of S1P(1)-overexpressing Chinese hamster ovary (CHO)-K1 cells, consistent with a functional antagonism. In vivo, both compounds induced a profound lymphopenia in mice. Finally, these substances showed efficacy in the EAE model, where they reduced clinical symptoms of the disease, and, on the molecular level, they reduced the T-cell infiltration and several inflammatory mediators in the brain and spinal cord. In summary, these data suggest that S1P(1)-selective compounds may have an advantage over fingolimod and siponimod, not only in MS but also in other autoimmune diseases.}, language = {en} } @article{ImeriFalleggerZivkovicetal.2014, author = {Imeri, Faik and Fallegger, Daniel and Zivkovic, Aleksandra and Schwalm, Stephanie and Enzmann, Gaby and Blankenbach, Kira and Heringdorf, Dagmar Meyer Zu and Homann, Thomas and Kleuser, Burkhard and Pfeilschifter, Josef and Engelhardt, Britta and Stark, Holger and Huwiler, Andrea}, title = {Novel oxazolo-oxazole derivatives of FTY720 reduce endothelial cell permeability, immune cell chemotaxis and symptoms of experimental autoimmune encephalomyelitis in mice}, series = {Neuropharmacology}, volume = {85}, journal = {Neuropharmacology}, publisher = {Elsevier}, address = {Oxford}, issn = {0028-3908}, doi = {10.1016/j.neuropharm.2014.05.012}, pages = {314 -- 327}, year = {2014}, abstract = {The immunomodulatory FTY720 (fingolimod) is presently approved for the treatment of relapsing-remitting multiple sclerosis. It is a prodrug that acts by modulating sphingosine 1-phosphate (S1P) receptor signaling. In this study, we have developed and characterized two novel oxazolo-oxazole derivatives of FTY720, ST-968 and the oxy analog ST-1071, which require no preceding activating phosphorylation, and proved to be active in intact cells and triggered S1P(1) and S1P(3), but not S1P(2), receptor internalization as a result of receptor activation. Functionally, ST-968 and ST-1071 acted similar to FTY720 to abrogate S1P-triggered chemotaxis of mouse splenocytes, mouse T cells and human U937 cells, and reduced TNFa- and LPS-stimulated endothelial cell permeability. The compounds also reduced TNF alpha-induced ICAM-1 and VCAM-1 mRNA expression, but restored TNF alpha-mediated downregulation of PECAM-1 mRNA expression. In an in vivo setting, the application of ST-968 or ST-1071 to mice resulted in a reduction of blood lymphocytes and significantly reduced the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice comparable to FTY720 either by prophylactic or therapeutic treatment. In parallel to the reduced clinical symptoms, infiltration of immune cells in the brain was strongly reduced, and in isolated tissues of brain and spinal cord, the mRNA and protein expressions of ICAM-1 and VCAM-1, as well as of matrix metalloproteinase-9 were reduced by all compounds, whereas PECAM-1 and tissue inhibitor of metalloproteinase TIMP-1 were upregulated. In summary, the data suggest that these novel butterfly derivatives of FTY720 could have considerable implication for future therapies of multiple sclerosis and other autoimmune diseases. (C) 2014 Elsevier Ltd. All rights reserved.}, language = {en} } @article{GoetzChmielewskiHomannetal.2014, author = {Goetz, Klaus-Peter and Chmielewski, Frank M. and Homann, Thomas and Huschek, Gerd and Matzneller, Philipp and Rawel, Harshadrai Manilal}, title = {Seasonal changes of physiological parameters in sweet cherry (Prunus avium L.) buds}, series = {Scientia horticulturae : an international journal sponsored by the International Society for Horticultural Science}, volume = {172}, journal = {Scientia horticulturae : an international journal sponsored by the International Society for Horticultural Science}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-4238}, doi = {10.1016/j.scienta.2014.04.012}, pages = {183 -- 190}, year = {2014}, abstract = {The transition from dormant stage to the beginning of growth was first obvious by markedly changes of the water content. The phase from green tip to tight cluster, with a length of only 4 days, was the period of the most physiological activity in single buds, because of the highest daily accumulation rates of fresh/dry weight, C, N. We assume a concentration dependant regulation of the member of the aspartate family (asparagine, aspartic acid, isoleucine) during dormancy, growth and development in sweet cherry buds. The ABA content showed 2011/12 a clear bimodal pattern which was at lower level similar in 2012/13, but not so strong incisive. In both years, the first peak was probably related to the end of endodormancy. However the ABA-isomer content showed in both seasons a unimodal pattern. The maximum of the ratio of ABA-isomer/ABA indicated the beginning of ontogenetic development which starts 3 and 2 weeks later, respectively. Our results suggest that ABA and the ABA-isomer in the sweet cherry buds regulate differentiated metabolic processes in the dormant stage and during bud growth and development. After replication in the season 2013/14 the estimated dates of release of endodormancy, beginning of ecodormancy and start of ontogenetic development will be used to validate and improve phenological models for the beginning of cherry blossom. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @misc{BaldermannHomannNeugartetal.2018, author = {Baldermann, Susanne and Homann, Thomas and Neugart, Susanne and Chmielewski, Frank M. and G{\"o}tz, Klaus-Peter and G{\"o}deke, Kristin and Huschek, Gerd and Morlock, Gertrud E. and Rawel, Harshadrai Manilal}, title = {Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.)}, series = {Molecules}, journal = {Molecules}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-417442}, pages = {19}, year = {2018}, abstract = {Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information.}, language = {en} } @article{BaldermannHomannNeugartetal.2018, author = {Baldermann, Susanne and Homann, Thomas and Neugart, Susanne and Chmielewski, Frank M. and G{\"o}tz, Klaus-Peter and G{\"o}deke, Kristin and Huschek, Gerd and Morlock, Gertrud E. and Rawel, Harshadrai Manilal}, title = {Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.)}, series = {Molecules}, volume = {23}, journal = {Molecules}, number = {5}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules23051197}, pages = {1 -- 19}, year = {2018}, abstract = {Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA) clearly differentiates the different timings of dormancy giving further valuable information.}, language = {en} } @article{UhrBuchholzHomannetal.2014, author = {Uhr, Linda and Buchholz, Tina and Homann, Thomas and Huschek, Gerd and Rawel, Harshadrai Manilal}, title = {Targeted proteomics-based analysis of technical enzymes from fungal origin in baked products}, series = {Journal of cereal science}, volume = {60}, journal = {Journal of cereal science}, number = {2}, publisher = {Elsevier}, address = {London}, issn = {0733-5210}, doi = {10.1016/j.jcs.2014.04.007}, pages = {440 -- 447}, year = {2014}, abstract = {The application of technical enzymes is a potential tool in modulating the dough and baking quality of cereal products. No endogenous amylases (alpha- and beta-forms) are present in mature wheat grains; they may be synthesized or activated during germination. Hence, microbial alpha-amylases are added to the dough, being resistant to the endogenous alpha-amylase/trypsin inhibitors. Here, we report on the initial identification of two technical enzymes from a commercial sample based on an in-gel tryptic digestion coupled with MALDI-MS analysis. The primary component of the protein fraction with 51.3 kDa was alpha-amylase from Aspergillus species. A second major protein with 24.8 kDa was identified as endo-1,4-xylanase from Thermomyces lanuginosus. In the following experimental work up, a targeted proteomics approach utilizing the combination of specific proteolytic digestion of the added amylase and xylanase in wheat flour, dough or baked products, solid phase extraction of released peptides and their detection using LC-MS/MS was optimized. The targeted (MRM) MS/MS peptide signals showed that the peptide "ALSSALHER" (MW = 983) originating from amylase and "GWNPGLNAR" (MW = 983) from xylanase can be used to identify the corresponding technical enzymes added. Consequently, locally available baked products were tested and found to contain these enzymes as supplementary ingredients. (C) 2014 Elsevier Ltd. All rights reserved.}, language = {en} } @article{GereckeSchumacherBerndzenetal.2019, author = {Gerecke, Christian and Schumacher, Fabian and Berndzen, Alide and Homann, Thomas and Kleuser, Burkhard}, title = {Vitamin C in combination with inhibition of mutant IDH1 synergistically activates TET enzymes and epigenetically modulates gene silencing in colon cancer cells}, series = {Epigenetics : the official journal of the DNA Methylation Society}, volume = {15}, journal = {Epigenetics : the official journal of the DNA Methylation Society}, number = {3}, publisher = {Taylor \& Francis Group}, address = {Philadelphia}, issn = {1559-2294}, doi = {10.1080/15592294.2019.1666652}, pages = {307 -- 322}, year = {2019}, abstract = {Mutations in the enzyme isocitrate dehydrogenase 1 (IDH1) lead to metabolic alterations and a sustained formation of 2-hydroxyglutarate (2-HG). 2-HG is an oncometabolite as it inhibits the activity of alpha-ketoglutarate-dependent dioxygenases such as ten-eleven translocation (TET) enzymes. Inhibitors of mutant IDH enzymes, like ML309, are currently tested in order to lower the levels of 2-HG. Vitamin C (VC) is an inducer of TET enzymes. To test a new therapeutic avenue of synergistic effects, the anti-neoplastic activity of inhibition of mutant IDH1 via ML309 in the presence of VC was investigated in the colon cancer cell line HCT116 IDH1(R132H/+) (harbouring a mutated IDH1 allele) and the parental cells HCT116 IDH1(+/+) (wild type IDH1). Measurement of the oncometabolite indicated a 56-fold higher content of 2-HG in mutated cells compared to wild type cells. A significant reduction of 2-HG was observed in mutated cells after treatment with ML 309, whereas VC produced only minimally changes of the oncometabolite. However, combinatorial treatment with both, ML309 and VC, in mutated cells induced pronounced reduction of 2-HG leading to levels comparable to those in wild type cells. The decreased level of 2-HG in mutated cells after combinatorial treatment was accompanied by an enhanced global DNA hydroxymethylation and an increased gene expression of certain tumour suppressors. Moreover, mutated cells showed an increased percentage of apoptotic cells after treatment with non-cytotoxic concentrations of ML309 and VC. These results suggest that combinatorial therapy is of interest for further investigation to rescue TET activity and treatment of IDH1/2 mutated cancers.}, language = {en} }