@phdthesis{Markova2016,
  author    = {Markova, Mariya},
  title     = {Metabolic and molecular effects of two different isocaloric high protein diets in subjects with type 2 diabetes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394310},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 127},
  year      = {2016},
  abstract  = {Ern{\"a}hrung stellt ein wichtiger Faktor in der Pr{\"a}vention und Therapie von Typ-2-Diabetes dar. Fr{\"u}here Studien haben gezeigt, dass Hochproteindi{\"a}ten sowohl positive als auch negative Effekte auf den Metabolismus hervorrufen. Jedoch ist unklar, ob die Herkunft des Proteins dabei eine Rolle spielt. In der LeguAN-Studie wurden die Effekte von zwei unterschiedlichen Hochproteindi{\"a}ten, entweder tierischer oder pflanzlicher Herkunft, bei Typ-2-Diabetes Patienten untersucht. Beide Di{\"a}ten enthielten 30 EN\% Proteine, 40 EN\% Kohlenhydrate und 30 EN\% Fette. Der Anteil an Ballaststoffen, der glyk{\"a}mischer Index und die Fettkomposition waren in beiden Di{\"a}ten {\"a}hnlich. Die Proteinaufnahme war h{\"o}her, w{\"a}hrend die Fettaufnahme niedriger im Vergleich zu den fr{\"u}heren Ern{\"a}hrungsgewohnheiten der Probanden war. Insgesamt f{\"u}hrten beide Di{\"a}tinterventionen zu einer Verbesserung der glyk{\"a}mischen Kontrolle, der Insulinsensitivit{\"a}t, des Leberfettgehalts und kardiovaskul{\"a}rer Risikomarkern ohne wesentliche Unterschiede zwischen den Proteintypen. In beiden Interventionsgruppen wurden die n{\"u}chternen Glukosewerte zusammen mit Indizes von Insulinresistenz in einem unterschiedlichen Ausmaß, jedoch ohne signifikante Unterschiede zwischen beiden Di{\"a}ten verbessert. Die Reduktion von HbA1c war ausgepr{\"a}gter in der pflanzlichen Gruppe, w{\"a}hrend sich die Insulinsensitivit{\"a}t mehr in der tierischen Gruppe erh{\"o}hte. Die Hochproteindi{\"a}ten hatten nur einen geringf{\"u}gigen Einfluss auf den postprandialen Metabolismus. Dies zeigte sich durch eine leichte Verbesserung der Indizes f{\"u}r Insulinsekretion, -sensitivit{\"a}t und -degradation sowie der Werte der freien Fetts{\"a}uren. Mit Ausnahme des Einflusses auf die GIP-Sekretion riefen die tierische und die pflanzliche Testmahlzeit {\"a}hnliche metabolische und hormonelle Antworten, trotz unterschiedlicher Aminos{\"a}urenzusammensetzung. Die tierische Hochproteindi{\"a}t f{\"u}hrte zu einer selektiven Zunahme der fettfreien Masse und Abnahme der Fettmasse, was nicht signifikant unterschiedlich von der pflanzlichen Gruppe war. Dar{\"u}ber hinaus reduzierten die Hochproteindi{\"a}ten den Leberfettgehalt um durchschnittlich 42\%. Die Reduktion des Leberfettgehaltes ging mit einer Verminderung der Lipogenese, der Lipolyse und des freien Fetts{\"a}ure Flux einher. Beide Interventionen induzierten einen moderaten Abfall von Leberenzymen im Blut. Die Reduktion des Leberfetts war mit einer verbesserten Glukosehom{\"o}ostase und Insulinsensitivit{\"a}t assoziiert. Blutlipide sanken in allen Probanden, was eventuell auf die niedrigere Fettaufnahme zur{\"u}ckzuf{\"u}hren war. Weiterhin waren die Spiegel an Harns{\"a}ure und Inflammationsmarkern erniedrigt unabh{\"a}ngig von der Proteinquelle. Die Werte des systolischen und diastolischen Blutdrucks sanken nur in der pflanzlichen Gruppe, was auf eine potentielle Rolle von Arginin hinweist. Es wurden keine Hinweise auf eine beeintr{\"a}chtigte Nierenfunktion durch die 6-w{\"o}chige Hochproteindi{\"a}ten beobachtet unabh{\"a}ngig von der Herkunft der Proteine. Serumkreatinin war nur in der pflanzlichen Gruppe signifikant reduziert, was eventuell an dem geringen Kreatingehalt der pflanzlichen Nahrungsmittel liegen k{\"o}nnte. Jedoch sind l{\"a}ngere Studien n{\"o}tig, um die Sicherheit von Hochproteindi{\"a}ten vollkommen aufkl{\"a}ren zu k{\"o}nnen. Des Weiteren verursachte keine der Di{\"a}ten eine Induktion des mTOR Signalwegs weder im Fettgewebe noch in Blutzellen. Die Verbesserung der Ganzk{\"o}rper-Insulinsensitivit{\"a}t deutete auch auf keine Aktivierung von mTOR und keine Verschlechterung der Insulinsensitivit{\"a}t im Skeletmuskel hin. Ein nennenswerter Befund war die erhebliche Reduktion von FGF21, einem wichtigen Regulator metabolischer Prozesse, um ungef{\"a}hr 50\% bei beiden Proteinarten. Ob hepatischer ER-Stress, Ammoniumniveau oder die Makron{\"a}hrstoffpr{\"a}ferenz hinter dem paradoxen Ergebnis stehen, sollte weiter im Detail untersucht werden. Entgegen der anf{\"a}nglichen Erwartung und der bisherigen Studienlage zeigte die pflanzlich-betonte Hochproteindi{\"a}t keine klaren Vorteile gegen{\"u}ber der tierischen Di{\"a}t. Der ausgepr{\"a}gte g{\"u}nstige Effekt des tierischen Proteins auf Insulinhom{\"o}ostase trotz des hohen BCAA-Gehaltes war sicherlich unerwartet und deutet darauf hin, dass bei dem l{\"a}ngeren Verzehr andere komplexe metabolische Adaptationen stattfinden. Einen weiteren Aspekt stellt der niedrigere Fettverzehr dar, der eventuell auch zu den Verbesserungen in beiden Gruppen beigetragen hat. Zusammenfassend l{\"a}sst sich sagen, dass eine 6-w{\"o}chige Di{\"a}t mit 30 EN\% Proteinen (entweder pflanzlich oder tierisch), 40 EN\% Kohlenhydraten und 30 EN\% Fetten mit weniger ges{\"a}ttigten Fetten zu metabolischen Verbesserungen bei Typ-2-Diabetes Patienten unabh{\"a}ngig von Proteinherkunft f{\"u}hrt.},
  language  = {en}
}
@misc{WessigBaderKlieretal.2016,
  author    = {Wessig, Pablo and Bader, Denise and Klier, Dennis Tobias and Hettrich, Cornelia and Bier, Frank Fabian},
  title     = {Detecting carbohydrate-lectin interactions using a fluorescent probe based on DBD dyes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394382},
  pages     = {1235 -- 1238},
  year      = {2016},
  abstract  = {Herein we present an efficient synthesis of a biomimetic probe with modular construction that can be specifically bound by the mannose binding FimH protein - a surface adhesion protein of E. coli bacteria. The synthesis combines the new and interesting DBD dye with the carbohydrate ligand mannose via a Click reaction. We demonstrate the binding to E. coli bacteria over a large concentration range and also present some special characteristics of those molecules that are of particular interest for the application as a biosensor. In particular, the mix-and-measure ability and the very good photo-stability should be highlighted here.},
  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}
}
@phdthesis{Ulaganathan2016,
  author    = {Ulaganathan, Vamseekrishna},
  title     = {Molecular fundamentals of foam fractionation},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94263},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 136},
  year      = {2016},
  abstract  = {Foam fractionation of surfactant and protein solutions is a process dedicated to separate surface active molecules from each other due to their differences in surface activities. The process is based on forming bubbles in a certain mixed solution followed by detachment and rising of bubbles through a certain volume of this solution, and consequently on the formation of a foam layer on top of the solution column. Therefore, systematic analysis of this whole process comprises of at first investigations dedicated to the formation and growth of single bubbles in solutions, which is equivalent to the main principles of the well-known bubble pressure tensiometry. The second stage of the fractionation process includes the detachment of a single bubble from a pore or capillary tip and its rising in a respective aqueous solution. The third and final stage of the process is the formation and stabilization of the foam created by these bubbles, which contains the adsorption layers formed at the growing bubble surface, carried up and gets modified during the bubble rising and finally ends up as part of the foam layer. Bubble pressure tensiometry and bubble profile analysis tensiometry experiments were performed with protein solutions at different bulk concentrations, solution pH and ionic strength in order to describe the process of accumulation of protein and surfactant molecules at the bubble surface. The results obtained from the two complementary methods allow understanding the mechanism of adsorption, which is mainly governed by the diffusional transport of the adsorbing protein molecules to the bubble surface. This mechanism is the same as generally discussed for surfactant molecules. However, interesting peculiarities have been observed for protein adsorption kinetics at sufficiently short adsorption times. First of all, at short adsorption times the surface tension remains constant for a while before it decreases as expected due to the adsorption of proteins at the surface. This time interval is called induction time and it becomes shorter with increasing protein bulk concentration. Moreover, under special conditions, the surface tension does not stay constant but even increases over a certain period of time. This so-called negative surface pressure was observed for BCS and BLG and discussed for the first time in terms of changes in the surface conformation of the adsorbing protein molecules. Usually, a negative surface pressure would correspond to a negative adsorption, which is of course impossible for the studied protein solutions. The phenomenon, which amounts to some mN/m, was rather explained by simultaneous changes in the molar area required by the adsorbed proteins and the non-ideality of entropy of the interfacial layer. It is a transient phenomenon and exists only under dynamic conditions. The experiments dedicated to the local velocity of rising air bubbles in solutions were performed in a broad range of BLG concentration, pH and ionic strength. Additionally, rising bubble experiments were done for surfactant solutions in order to validate the functionality of the instrument. It turns out that the velocity of a rising bubble is much more sensitive to adsorbing molecules than classical dynamic surface tension measurements. At very low BLG or surfactant concentrations, for example, the measured local velocity profile of an air bubble is changing dramatically in time scales of seconds while dynamic surface tensions still do not show any measurable changes at this time scale. The solution's pH and ionic strength are important parameters that govern the measured rising velocity for protein solutions. A general theoretical description of rising bubbles in surfactant and protein solutions is not available at present due to the complex situation of the adsorption process at a bubble surface in a liquid flow field with simultaneous Marangoni effects. However, instead of modelling the complete velocity profile, new theoretical work has been started to evaluate the maximum values in the profile as characteristic parameter for dynamic adsorption layers at the bubble surface more quantitatively. The studies with protein-surfactant mixtures demonstrate in an impressive way that the complexes formed by the two compounds change the surface activity as compared to the original native protein molecules and therefore lead to a completely different retardation behavior of rising bubbles. Changes in the velocity profile can be interpreted qualitatively in terms of increased or decreased surface activity of the formed protein-surfactant complexes. It was also observed that the pH and ionic strength of a protein solution have strong effects on the surface activity of the protein molecules, which however, could be different on the rising bubble velocity and the equilibrium adsorption isotherms. These differences are not fully understood yet but give rise to discussions about the structure of protein adsorption layer under dynamic conditions or in the equilibrium state. The third main stage of the discussed process of fractionation is the formation and characterization of protein foams from BLG solutions at different pH and ionic strength. Of course a minimum BLG concentration is required to form foams. This minimum protein concentration is a function again of solution pH and ionic strength, i.e. of the surface activity of the protein molecules. Although at the isoelectric point, at about pH 5 for BLG, the hydrophobicity and hence the surface activity should be the highest, the concentration and ionic strength effects on the rising velocity profile as well as on the foamability and foam stability do not show a maximum. This is another remarkable argument for the fact that the interfacial structure and behavior of BLG layers under dynamic conditions and at equilibrium are rather different. These differences are probably caused by the time required for BLG molecules to adapt respective conformations once they are adsorbed at the surface. All bubble studies described in this work refer to stages of the foam fractionation process. Experiments with different systems, mainly surfactant and protein solutions, were performed in order to form foams and finally recover a solution representing the foamed material. As foam consists to a large extent of foam lamella - two adsorption layers with a liquid core - the concentration in a foamate taken from foaming experiments should be enriched in the stabilizing molecules. For determining the concentration of the foamate, again the very sensitive bubble rising velocity profile method was applied, which works for any type of surface active materials. This also includes technical surfactants or protein isolates for which an accurate composition is unknown.},
  language  = {en}
}