TY - JOUR A1 - Nakamura, Yasunori A1 - Steup, Martin A1 - Colleoni, Christophe A1 - Iglesias, Alberto A. A1 - Bao, Jinsong A1 - Fujita, Naoko A1 - Tetlow, Ian T1 - Molecular regulation of starch metabolism JF - Plant molecular biology : an international journal of fundamental research and genetic engineering Y1 - 2022 U6 - https://doi.org/10.1007/s11103-022-01253-0 SN - 0167-4412 SN - 1573-5028 VL - 108 IS - 4-5 SP - 289 EP - 290 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Cisek, Richard A1 - Tokarz, Danielle A1 - Kontenis, Lukas A1 - Barzda, Virginijus A1 - Steup, Martin T1 - Polarimetric second harmonic generation microscopy BT - an analytical tool for starch bioengineering JF - Starch-Starke N2 - Second harmonic generation (SHG) is a nonlinear optical process that inherently generates signal in non-centrosymmetric materials, such as starch granules, and therefore can be used for label-free imaging. Both intensity and polarization of SHG are determined by material properties that are characterized by the nonlinear susceptibility tensor, ((2)). Examination of the tensor is performed for each focal volume of the image by measuring the outgoing polarization state of the SHG signal for a set of incoming laser beam polarizations. Mapping of nonlinear properties expressed as the susceptibility ratio reveals structural features including the organization of crystalline material within a single starch granule, and the distribution of structural properties in a population of granules. Isolated granules, as well as in situ starch, can be analyzed using polarimetric SHG microscopy. Due to the fast sample preparation and short imaging times, polarimetric SHG microscopy allows for a quick assessment of starch structure and permits rapid feedback for bioengineering applications. This article presents the basics of SHG theory and microscopy applications for starch-containing materials. Quantification of ultrastructural features within individual starch granules is described. New results obtained by polarization resolved SHG microscopy of starch granules are presented for various maize genotypes revealing heterogeneity within a single starch particle and between various granules. KW - Determination of crystallinity KW - Determination of hydration KW - Label-free imaging KW - Nonlinear optical microscopy KW - Structural determination Y1 - 2017 U6 - https://doi.org/10.1002/star.201700031 SN - 0038-9056 SN - 1521-379X VL - 70 IS - 1-2 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Sullivan, Mitchell A. A1 - Nitschke, Silvia A1 - Steup, Martin A1 - Minassian, Berge A. A1 - Nitschke, Felix T1 - Pathogenesis of Lafora disease BT - transition of soluble glycogen to insoluble polyglucosan T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Lafora disease (LD, OMIM #254780) is a rare, recessively inherited neurodegenerative disease with adolescent onset, resulting in progressive myoclonus epilepsy which is fatal usually within ten years of symptom onset. The disease is caused by loss-of-function mutations in either of the two genes EPM2A (laforin) or EPM2B (malin). It characteristically involves the accumulation of insoluble glycogen-derived particles, named Lafora bodies (LBs), which are considered neurotoxic and causative of the disease. The pathogenesis of LD is therefore centred on the question of how insoluble LBs emerge from soluble glycogen. Recent data clearly show that an abnormal glycogen chain length distribution, but neither hyperphosphorylation nor impairment of general autophagy, strictly correlates with glycogen accumulation and the presence of LBs. This review summarizes results obtained with patients, mouse models, and cell lines and consolidates apparent paradoxes in the LD literature. Based on the growing body of evidence, it proposes that LD is predominantly caused by an impairment in chain-length regulation affecting only a small proportion of the cellular glycogen. A better grasp of LD pathogenesis will further develop our understanding of glycogen metabolism and structure. It will also facilitate the development of clinical interventions that appropriately target the underlying cause of LD. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1080 KW - lafora disease KW - laforin KW - malin KW - polyglucosan body KW - chain length distribution KW - glycogen phosphorylation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-474622 SN - 1866-8372 IS - 1080 ER - TY - JOUR A1 - Dauvillee, David A1 - Chochois, Vincent A1 - Steup, Martin A1 - Haebel, Sophie A1 - Eckermann, Nora A1 - Ritte, Gerhard A1 - Ral, Jean-Philippe A1 - Colleoni, Christophe A1 - Hicks, Glenn A1 - Wattebled, Fabrice A1 - Deschamps, Philippe A1 - Lienard, Luc A1 - Cournac, Laurent A1 - Putaux, Jean-Luc A1 - Dupeyre, Danielle A1 - Ball, Steven G. T1 - Plastidial phosphorylase is required for normal starch synthesis in Chlamydomonas reinhardtii JF - The plant journal N2 - Among the three distinct starch phosphorylase activities detected in Chlamydomonas reinhardtii, two distinct plastidial enzymes (PhoA and PhoB) are documented while a single extraplastidial form (PhoC) displays a higher affinity for glycogen as in vascular plants. The two plastidial phosphorylases are shown to function as homodimers containing two 91-kDa (PhoA) subunits and two 110-kDa (PhoB) subunits. Both lack the typical 80-amino-acid insertion found in the higher plant plastidial forms. PhoB is exquisitely sensitive to inhibition by ADP-glucose and has a low affinity for malto-oligosaccharides. PhoA is more similar to the higher plant plastidial phosphorylases: it is moderately sensitive to ADP-glucose inhibition and has a high affinity for unbranched malto-oligosaccharides. Molecular analysis establishes that STA4 encodes PhoB. Chlamydomonas reinhardtii strains carrying mutations at the STA4 locus display a significant decrease in amounts of starch during storage that correlates with the accumulation of abnormally shaped granules containing a modified amylopectin structure and a high amylose content. The wild-type phenotype could be rescued by reintroduction of the cloned wild-type genomic DNA, thereby demonstrating the involvement of phosphorylase in storage starch synthesis. KW - Chlamydomonas KW - starch KW - amylopectin KW - (glycogen) starch phosphorylase Y1 - 2006 U6 - https://doi.org/10.1111/j.1365-313X.2006.02870.x SN - 0960-7412 VL - 48 IS - 2 SP - 274 EP - 285 PB - Blackwell CY - Oxford ER - TY - JOUR A1 - Ritte, Gerhard A1 - Heydenreich, Matthias A1 - Mahlow, Sebastian A1 - Haebel, Sophie A1 - Koetting, Oliver A1 - Steup, Martin T1 - Phosphorylation of C6- and C3-positions of glucosyl residues in starch is catalysed by distinct dikinases JF - FEBS letters : the journal for rapid publication of short reports in molecular biosciences N2 - Glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD) are required for normal starch metabolism. We analysed starch phosphorylation in Arabidopsis wildtype plants and mutants lacking either GWD or PWD using P-31 NMR. Phosphorylation at both C6- and C3-positions of glucose moieties in starch was drastically decreased in GWD-deficient mutants. In starch from PWD-deficient plants C3-bound phosphate was reduced to levels close to the detection limit. The latter result contrasts with previous reports according to which GWD phosphorylates both C6- and C3-positions. In these studies, phosphorylation had been analysed by HPLC of acid-hydrolysed glucans. We now show that maltose-6-phosphate, a product of incomplete starch hydrolysis, co-eluted with glucose-3-phosphate under the chromatographic conditions applied. Re-examination of the specificity of the dikinases using an improved method demonstrates that C6- and C3-phosphorylation is selectively catalysed by GWD and PWD, respectively. KW - starch phosphorylation KW - GWD KW - PWD KW - P-31 NMR Y1 - 2006 U6 - https://doi.org/10.1016/j.febslet.2006.07.085 SN - 0014-5793 VL - 580 IS - 20 SP - 4872 EP - 4876 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Smirnova, Julia A1 - Fernie, Alisdair R. A1 - Spahn, Christian M. T. A1 - Steup, Martin T1 - Photometric assay of maltose and maltose-forming enzyme activity by using 4-alpha-glucanotransferase (DPE2) from higher plants JF - Analytical biochemistry : methods in the biological sciences N2 - Maltose frequently occurs as intermediate of the central carbon metabolism of prokaryotic and eukaryotic cells. Various mutants possess elevated maltose levels. Maltose exists as two anomers, (alpha- and beta-form) which are rapidly interconverted without requiring enzyme-mediated catalysis. As maltose is often abundant together with other oligoglucans, selective quantification is essential. In this communication, we present a photometric maltose assay using 4-alpha-glucanotransferase (AtDPE2) from Arabidopsis thaliana. Under in vitro conditions, AtDPE2 utilizes maltose as glucosyl donor and glycogen as acceptor releasing the other hexosyl unit as free glucose which is photometrically quantified following enzymatic phosphorylation and oxidation. Under the conditions used, DPE2 does not noticeably react with other di- or oligosaccharides. Selectivity compares favorably with that of maltase frequently used in maltose assays. Reducing end interconversion of the two maltose anomers is in rapid equilibrium and, therefore, the novel assay measures total maltose contents. Furthermore, an AtDPE2-based continuous photometric assay is presented which allows to quantify beta-amylase activity and was found to be superior to a conventional test. Finally, the AtDPE2-based maltose assay was used to quantify leaf maltose contents of both Arabidopsis wild type and AtDPE2-deficient plants throughout the light-dark cycle. These data are presented together with assimilatory starch levels. (C) 2017 Published by Elsevier Inc. KW - Arabidopsis thaliana KW - beta-amylase assay KW - Disproportionating isozyme 2 (DPE2) dpe2-deficient plants KW - Maltose assay KW - Leaf maltose content Y1 - 2017 U6 - https://doi.org/10.1016/j.ab.2017.05.026 SN - 0003-2697 SN - 1096-0309 VL - 532 SP - 72 EP - 82 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Jüppner, Jessica A1 - Mubeen, Umarah A1 - Leisse, Andrea A1 - Caldana, Camila A1 - Brust, Henrike A1 - Steup, Martin A1 - Herrmann, Marion A1 - Steinhauser, Dirk A1 - Giavalisco, Patrick T1 - Dynamics of lipids and metabolites during the cell cycle of Chlamydomonas reinhardtii JF - The plant journal N2 - Metabolites and lipids are the final products of enzymatic processes, distinguishing the different cellular functions and activities of single cells or whole tissues. Understanding these cellular functions within a well-established model system requires a systemic collection of molecular and physiological information. In the current report, the green alga Chlamydomonas reinhardtii was selected to establish a comprehensive workflow for the detailed multi-omics analysis of a synchronously growing cell culture system. After implementation and benchmarking of the synchronous cell culture, a two-phase extraction method was adopted for the analysis of proteins, lipids, metabolites and starch from a single sample aliquot of as little as 10-15million Chlamydomonas cells. In a proof of concept study, primary metabolites and lipids were sampled throughout the diurnal cell cycle. The results of these time-resolved measurements showed that single compounds were not only coordinated with each other in different pathways, but that these complex metabolic signatures have the potential to be used as biomarkers of various cellular processes. Taken together, the developed workflow, including the synchronized growth of the photoautotrophic cell culture, in combination with comprehensive extraction methods and detailed metabolic phenotyping has the potential for use in in-depth analysis of complex cellular processes, providing essential information for the understanding of complex biological systems. KW - Chlamydomonas reinhardtii KW - synchronized cell cultures KW - photoautotrophic growth KW - cell cycle KW - metabolomics KW - lipidomics KW - systems biology KW - two-phase extraction KW - diurnal cycle KW - technical advance Y1 - 2017 U6 - https://doi.org/10.1111/tpj.13642 SN - 0960-7412 SN - 1365-313X VL - 92 SP - 331 EP - 343 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Nakamura, Yasunori A1 - Ono, Masami A1 - Sawada, Takayuki A1 - Crofts, Naoko A1 - Fujita, Naoko A1 - Steup, Martin T1 - Characterization of the functional interactions of plastidial starch phosphorylase and starch branching enzymes from rice endosperm during reserve starch biosynthesis JF - Plant science : an international journal of experimental plant biology N2 - Functional interactions of plastidial phosphorylase (Phol) and starch branching enzymes (BEs) from the developing rice endosperm are the focus of this study. In the presence of both Phol and BE, the same branched primer molecule is elongated and further branched almost simultaneously even at very low glucan concentrations present in the purified enzyme preparations. By contrast, in the absence of any BE, glucans are not, to any significant extent, elongated by Phol. Based on our in vitro data, in the developing rice endosperm, Phol appears to be weakly associated with any of the BE isozymes. By using fluorophore-labeled malto-oligosaccharides, we identified maltose as the smallest possible primer for elongation by Phol. Linear dextrins act as carbohydrate substrates for BEs. By functionally interacting with a BE, Phol performs two essential functions during the initiation of starch biosynthesis in the rice endosperm: First, it elongates maltodextrins up to a degree of polymerization of at least 60. Second, by closely interacting with BEs, Phol is able to elongate branched glucans efficiently and thereby synthesizes branched carbohydrates essential for the initiation of amylopectin biosynthesis. Y1 - 2017 U6 - https://doi.org/10.1016/j.plantsci.2017.09.002 SN - 0168-9452 VL - 264 SP - 83 EP - 95 PB - Elsevier CY - Clare ER - TY - JOUR A1 - Volk, Benno A1 - Markert, Doreen A1 - Riejok, Henriette A1 - Dittberner, Jürgen A1 - Wanka, Johanna A1 - Wilkens, Martin A1 - Görtemaker, Manfred A1 - Regierer, Babette A1 - Steup, Martin A1 - Müller-Röber, Bernd A1 - Wernicke, Matthias A1 - Altenberger, Uwe A1 - Stölting, Erhard A1 - Ferý, Carolin A1 - Egenter, Peter A1 - Lenz, Claudia A1 - Jakubowski, Zuzanna A1 - Klötzer, Sylvia A1 - Krause, Michael A1 - Dietsch, Ulrich T1 - Portal = Vor der Präsidenten-Wahl: Erwartungen, Wünsche, Vorschläge BT - Die Potsdamer Universitätszeitung N2 - Aus dem Inhalt: - Vor der Präsidenten-Wahl: Erwartungen, Wünsche, Vorschläge - Der AStA in der Krise? - Über Satire und Macht in der DDR - Vom Fünf-Sterne-Koch zum Mensaleiter T3 - Portal: Das Potsdamer Universitätsmagazin - 04-05/2006 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-440005 SN - 1618-6893 IS - 04-05/2006 ER - TY - GEN A1 - Schwarte, Sandra A1 - Brust, Henrike A1 - Steup, Martin A1 - Tiedemann, Ralph T1 - Intraspecific sequence variation and differential expression in starch synthase genes of Arabidopsis thaliana T2 - BMC Research Notes N2 - Background Natural accessions of Arabidopsis thaliana are a well-known system to measure levels of intraspecific genetic variation. Leaf starch content correlates negatively with biomass. Starch is synthesized by the coordinated action of many (iso)enzymes. Quantitatively dominant is the repetitive transfer of glucosyl residues to the non-reducing ends of α-glucans as mediated by starch synthases. In the genome of A. thaliana, there are five classes of starch synthases, designated as soluble starch synthases (SSI, SSII, SSIII, and SSIV) and granule-bound synthase (GBSS). Each class is represented by a single gene. The five genes are homologous in functional domains due to their common origin, but have evolved individual features as well. Here, we analyze the extent of genetic variation in these fundamental protein classes as well as possible functional implications on transcript and protein levels. Findings Intraspecific sequence variation of the five starch synthases was determined by sequencing the entire loci including promoter regions from 30 worldwide distributed accessions of A. thaliana. In all genes, a considerable number of nucleotide polymorphisms was observed, both in non-coding and coding regions, and several amino acid substitutions were identified in functional domains. Furthermore, promoters possess numerous polymorphisms in potentially regulatory cis-acting regions. By realtime experiments performed with selected accessions, we demonstrate that DNA sequence divergence correlates with significant differences in transcript levels. Conclusions Except for AtSSII, all starch synthase classes clustered into two or three groups of haplotypes, respectively. Significant difference in transcript levels among haplotype clusters in AtSSIV provides evidence for cis-regulation. By contrast, no such correlation was found for AtSSI, AtSSII, AtSSIII, and AtGBSS, suggesting trans-regulation. The expression data presented here point to a regulation by common trans-regulatory transcription factors which ensures a coordinated action of the products of these four genes during starch granule biosynthesis. The apparent cis-regulation of AtSSIV might be related to its role in the initiation of de novo biosynthesis of granules. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 400 KW - Arabidopsis thaliana KW - starch synthases KW - genetic variation KW - transcript level Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-401128 ER -