TY - JOUR A1 - Annunziata, Maria Grazia A1 - Apelt, Federico A1 - Carillo, Petronia A1 - Krause, Ursula A1 - Feil, Regina A1 - Mengin, Virginie A1 - Lauxmann, Martin A. A1 - Koehl, Karin A1 - Nikoloski, Zoran A1 - Stitt, Mark A1 - Lunn, John Edward T1 - Getting back to nature: a reality check for experiments in controlled environments JF - Journal of experimental botany N2 - Irradiance from sunlight changes in a sinusoidal manner during the day, with irregular fluctuations due to clouds, and light-dark shifts at dawn and dusk are gradual. Experiments in controlled environments typically expose plants to constant irradiance during the day and abrupt light-dark transitions. To compare the effects on metabolism of sunlight versus artificial light regimes, Arabidopsis thaliana plants were grown in a naturally illuminated greenhouse around the vernal equinox, and in controlled environment chambers with a 12-h photoperiod and either constant or sinusoidal light profiles, using either white fluorescent tubes or light-emitting diodes (LEDs) tuned to a sunlight-like spectrum as the light source. Rosettes were sampled throughout a 24-h diurnal cycle for metabolite analysis. The diurnal metabolite profiles revealed that carbon and nitrogen metabolism differed significantly between sunlight and artificial light conditions. The variability of sunlight within and between days could be a factor underlying these differences. Pairwise comparisons of the artificial light sources (fluorescent versus LED) or the light profiles (constant versus sinusoidal) showed much smaller differences. The data indicate that energy-efficient LED lighting is an acceptable alternative to fluorescent lights, but results obtained from plants grown with either type of artificial lighting might not be representative of natural conditions. KW - Amino acid KW - Arabidopsis thaliana KW - controlled environment KW - LED lighting KW - visible light spectrum KW - organic acid KW - starch KW - sucrose KW - trehalose 6-phosphate Y1 - 2017 U6 - https://doi.org/10.1093/jxb/erx220 SN - 0022-0957 SN - 1460-2431 VL - 68 SP - 4463 EP - 4477 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Söll, Änne A1 - Köstler, Andreas A1 - Krause, Regina A1 - Ludwig, Joachim A1 - Pohlenz, Philipp A1 - Rößler, Dirk A1 - Kirf, Marcel A1 - Klein, Armin A1 - Wagner, Nelli A1 - Angelow, Jürgen T1 - Portal = Pläne vorgelegt: Maßnahmen zur Studienreform BT - Das Potsdamer Universitätsmagazin N2 - Aus dem Inhalt: - Pläne vorgelegt: Maßnahmen zur Studienreform - Fische lügen beim Sex - Käfersammlerin des 21. Jahrhunderts T3 - Portal: Das Potsdamer Universitätsmagazin - 10-12/2008 Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-440162 SN - 1618-6893 IS - 10-12/2008 ER - TY - JOUR A1 - Khalil, Mahmoud A1 - Raila, Jens A1 - Ali, Mostafa A1 - Islam, Khan M. S. A1 - Schenk, Regina A1 - Krause, Jens-Peter A1 - Schweigert, Florian J. A1 - Rawel, Harshadrai Manilal T1 - Stability and bioavailability of lutein ester supplements from Tagetes flower prepared under food processing conditions JF - Journal of functional food N2 - Tagetes spp. belongs to the Asteraceae family. It is recognized as a major source of lutein ester (lutein esterified with fatty acids such as lauric, myristic and palmitic acids), a natural colorant belonging to the xanthophylls or oxygenated carotenoids. Four species of Tagetes flower (Tagetes tenuifolia, Tagetes erecta, Tagetes patula, and Tagetes lucida) were used to extract lutein and lutein esters with three different methods. The results showed that T. erecta, type "orangeprinz", is the richest source of lutein esters (14.4 +/- 0.234 mg/g) in comparison to other Tagetes spp. No significant differences between extractions of lutein esters with medium-chain triacylglycerols (MCT) oil, orange oil or solvent (hexane/isopropanol) could be observed. MCT oil also improved stability of lutein esters at 100 degrees C for 40 min. Emulsification of MCT oil improved the stability of lutein ester extract against UV light at 365 nm for 72 h. Finally, an emulsion was prepared under food processing conditions, spray dried and its bioavailability investigated in a preliminary human intervention study. The results show a lower resorption, but further data suggest improvements in implementation of such supplements. (c) 2012 Elsevier Ltd. All rights reserved. KW - Tagetes KW - Lutein ester KW - Emulsion KW - Stability KW - Whey protein KW - Bioavailability Y1 - 2012 U6 - https://doi.org/10.1016/j.jff.2012.03.006 SN - 1756-4646 VL - 4 IS - 3 SP - 602 EP - 610 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Martins, Marina Camara Mattos A1 - Hejazi, Mahdi A1 - Fettke, Jörg A1 - Steup, Martin A1 - Feil, Regina A1 - Krause, Ursula A1 - Arrivault, Stephanie A1 - Vosloh, Daniel A1 - Figueroa, Carlos Maria A1 - Ivakov, Alexander A1 - Yadav, Umesh Prasad A1 - Piques, Maria A1 - Metzner, Daniela A1 - Stitt, Mark A1 - Lunn, John Edward T1 - Feedback inhibition of starch degradation in arabidopsis leaves mediated by trehalose 6-phosphate JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by beta-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 mu M in the cytosol, 0.2 to 0.5 mu M in the chloroplasts, and 0.05 mu M in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night. Y1 - 2013 U6 - https://doi.org/10.1104/pp.113.226787 SN - 0032-0889 SN - 1532-2548 VL - 163 IS - 3 SP - 1142 EP - 1163 PB - American Society of Plant Physiologists CY - Rockville ER - TY - JOUR A1 - Fichtner, Franziska A1 - Olas, Justyna Jadwiga A1 - Feil, Regina A1 - Watanabe, Mutsumi A1 - Krause, Ursula A1 - Hoefgen, Rainer A1 - Stitt, Mark A1 - Lunn, John Edward T1 - Functional features of Trehalose-6-Phosphate Synthase 1 BT - an essential enzyme in Arabidopsis JF - The Plant Cell N2 - Tre6P synthesis by TPS1 is essential for embryogenesis and postembryonic growth in Arabidopsis, and appropriate Suc signaling by Tre6P is dependent on the noncatalytic domains of TPS1. In Arabidopsis (Arabidopsis thaliana), TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) catalyzes the synthesis of the sucrose-signaling metabolite trehalose 6-phosphate (Tre6P) and is essential for embryogenesis and normal postembryonic growth and development. To understand its molecular functions, we transformed the embryo-lethal tps1-1 null mutant with various forms of TPS1 and with a heterologous TPS (OtsA) from Escherichia coli, under the control of the TPS1 promoter, and tested for complementation. TPS1 protein localized predominantly in the phloem-loading zone and guard cells in leaves, root vasculature, and shoot apical meristem, implicating it in both local and systemic signaling of Suc status. The protein is targeted mainly to the nucleus. Restoring Tre6P synthesis was both necessary and sufficient to rescue the tps1-1 mutant through embryogenesis. However, postembryonic growth and the sucrose-Tre6P relationship were disrupted in some complementation lines. A point mutation (A119W) in the catalytic domain or truncating the C-terminal domain of TPS1 severely compromised growth. Despite having high Tre6P levels, these plants never flowered, possibly because Tre6P signaling was disrupted by two unidentified disaccharide-monophosphates that appeared in these plants. The noncatalytic domains of TPS1 ensure its targeting to the correct subcellular compartment and its catalytic fidelity and are required for appropriate signaling of Suc status by Tre6P. KW - cyanobacterial sucrose-phosphatase KW - trehalose 6-phosphate KW - vegetative growth KW - crystal-structure KW - gene-expression KW - thaliana KW - metabolism KW - phosphorylation KW - reveals KW - proteins Y1 - 2020 U6 - https://doi.org/10.1105/tpc.19.00837 SN - 0032-0781 SN - 1471-9053 VL - 32 IS - 6 SP - 1949 EP - 1972 PB - Oxford University Press CY - Oxford ER - TY - GEN A1 - Fichtner, Franziska A1 - Olas, Justyna Jadwiga A1 - Feil, Regina A1 - Watanabe, Mutsumi A1 - Krause, Ursula A1 - Hoefgen, Rainer A1 - Stitt, Mark A1 - Lunn, John Edward T1 - Functional features of Trehalose-6-Phosphate Synthase 1 BT - an essential enzyme in Arabidopsis T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Tre6P synthesis by TPS1 is essential for embryogenesis and postembryonic growth in Arabidopsis, and appropriate Suc signaling by Tre6P is dependent on the noncatalytic domains of TPS1. In Arabidopsis (Arabidopsis thaliana), TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) catalyzes the synthesis of the sucrose-signaling metabolite trehalose 6-phosphate (Tre6P) and is essential for embryogenesis and normal postembryonic growth and development. To understand its molecular functions, we transformed the embryo-lethal tps1-1 null mutant with various forms of TPS1 and with a heterologous TPS (OtsA) from Escherichia coli, under the control of the TPS1 promoter, and tested for complementation. TPS1 protein localized predominantly in the phloem-loading zone and guard cells in leaves, root vasculature, and shoot apical meristem, implicating it in both local and systemic signaling of Suc status. The protein is targeted mainly to the nucleus. Restoring Tre6P synthesis was both necessary and sufficient to rescue the tps1-1 mutant through embryogenesis. However, postembryonic growth and the sucrose-Tre6P relationship were disrupted in some complementation lines. A point mutation (A119W) in the catalytic domain or truncating the C-terminal domain of TPS1 severely compromised growth. Despite having high Tre6P levels, these plants never flowered, possibly because Tre6P signaling was disrupted by two unidentified disaccharide-monophosphates that appeared in these plants. The noncatalytic domains of TPS1 ensure its targeting to the correct subcellular compartment and its catalytic fidelity and are required for appropriate signaling of Suc status by Tre6P. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1432 KW - cyanobacterial sucrose-phosphatase KW - trehalose 6-phosphate KW - vegetative growth KW - crystal-structure KW - gene-expression KW - thaliana KW - metabolism KW - phosphorylation KW - reveals KW - proteins Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516532 SN - 1866-8372 IS - 6 ER -