zur Suche springenzur Navigation springenzum Inhalt springen

Publikationen - Stoffwechsel- und Zellbiologie

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 71 bis 80 von 225.

Publikation

Schliemann, W.; Schneider, B.; Wray, V.; Schmidt, J.; Nimtz, M.; Porzel, A.; Böhm, H.; Flavonols and an indole alkaloid skeleton bearing identical acylated glycosidic groups from yellow petals of Papaver nudicaule Phytochemistry 67, 191-201, (2006) DOI: 10.1016/j.phytochem.2005.11.002

From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-β-sophoroside and kaempferol 3-O-β-sophoroside-7-O-β-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.
Publikation

Schliemann, W.; Schmidt, J.; Nimtz, M.; Wray, V.; Fester, T.; Strack, D.; Erratum to “Accumulation of apocarotenoids in mycorrhizal roots of Ornithogalum umbellatum” [Phytochem. 67 (2006) 1196–1205] Phytochemistry 67, 2090, (2006) DOI: 10.1016/j.phytochem.2006.07.018

0
Publikation

Schliemann, W.; Schmidt, J.; Nimtz, M.; Wray, V.; Fester, T.; Strack, D.; Accumulation of apocarotenoids in mycorrhizal roots of Ornithogalum umbellatum Phytochemistry 67, 1196-1205, (2006) DOI: 10.1016/j.phytochem.2006.05.005

Colonization of roots of Ornithogalum umbellatum by the arbuscular mycorrhizal fungus Glomus intraradices induced the accumulation of different types of apocarotenoids. In addition to the mycorrhiza-specific occurrence of cyclohexenone derivatives and the “yellow pigment” described earlier, free mycorradicin and numerous mycorradicin derivatives were detected in a complex apocarotenoid mixture for the first time. From the accumulation pattern of the mycorradicin derivatives their possible integration into the continuously accumulating “yellow pigment” is suggested. Structure analyses of the cyclohexenone derivatives by MS and NMR revealed that they are mono-, di- and branched triglycosides of blumenol C, 13-hydroxyblumenol C, and 13-nor-5-carboxy-blumenol C, some of which contain terminal rhamnose as sugar moiety.
Publikation

Schaarschmidt, S.; Roitsch, T.; Hause, B.; Arbuscular mycorrhiza induces gene expression of the apoplastic invertase LIN6 in tomato (Lycopersicon esculentum) roots J. Exp. Bot. 57, 4015-4023, (2006) DOI: 10.1093/jxb/erl172

Extracellular invertases are suggested to play a crucial role in the arbuscular mycorrhiza (AM) symbiosis to fulfil the increased sink function of the mycorrhizal root and the supply of the obligate biotrophic AM fungus with hexoses. In tomato (Lycopersicon esculentum), LIN6 represents an apoplastic invertase which is described as a key enzyme in establishing and maintaining sink metabolism. In this study, transcript levels of LIN6 were analysed in tomato roots colonized with the AM fungus Glomus intraradices. Using real-time RT–PCR, a nearly 3-fold increase in LIN6 mRNA levels was detected at late stages of mycorrhization (11 weeks after inoculation). A 1.8-fold induction could already be achieved at earlier stages (5 weeks after inoculation) using higher inoculum concentrations, whereas wounding of non-mycorrhizal roots resulted in up to 12-fold enhanced LIN6 transcripts. As revealed by in situ hybridization, the expression of LIN6 upon mycorrhization was specifically restricted to colonized cells and to the central cylinder. Such a strongly localized pattern due to mycorrhizal cells and to the central core could also be shown for promoter activity using transgenic Nicotiana tabacum plants expressing the gene coding for β-glucuronidase under the control of the LIN6 promoter. The moderate induction of LIN6 expression in mycorrhizal tomato roots compared with stress-stimulated induction suggested a fine-tuning in the activation of sink metabolism in the mutualistic interaction, avoiding stress-induced defence reactions.
Publikation

Ziegler, J.; Diaz-Chávez, M. L.; Kramell, R.; Ammer, C.; Kutchan, T. M.; Comparative macroarray analysis of morphine containing Papaver somniferum and eight morphine free Papaver species identifies an O-methyltransferase involved in benzylisoquinoline biosynthesis Planta 222, 458-471, (2005) DOI: 10.1007/s00425-005-1550-4

Benzylisoquinoline alkaloids constitute a group of about 2,500 structures and are mainly produced by plants of the order Ranunculales. But only the opium poppy, Papaver somniferum, and Papaver setigerum are able to produce morphine. In this study, we started to investigate by gene expression analysis the molecular basis for this exceptional biosynthetic ability. A sequencing project from P. somniferum seedlings was initiated using a method based on the amplified fragment length polymorphism technique that resulted in 849 UniGenes. These cDNAs were analysed on macroarrays for differential expression between morphine-containing P. somniferum plants and eight other Papaver species, which accumulate other benzylisoquinolines instead of morphine. Three cDNAs showing increased expression in P. somniferum compared to all the other Papaver species were identified. Whereas two showed no significant homology to any known protein, one putatively encoded an O-methyltransferase. Analysis of substrate specificity of the heterologously expressed protein and mass spectrometric identification of the enzymatic products identified this protein as S-adenosyl-L-methionine:(R,S)-3′-hydroxy-N-methylcoclaurine 4′-O-methyltransferase (EC 2.1.1.116). Unlike other O-methyltransferases of different positional specificities implicated in benzylisoquinoline metabolism, the enzyme only accepted tetrahydroxylated tetrahydrobenzylisoquinolines as substrates; methylation was tolerated only at the 6-hydroxy position.
Publikation

Lohse, S.; Schliemann, W.; Ammer, C.; Kopka, J.; Strack, D.; Fester, T.; Organization and Metabolism of Plastids and Mitochondria in Arbuscular Mycorrhizal Roots of Medicago truncatula Plant Physiol. 139, 329-340, (2005) DOI: 10.1104/pp.105.061457

Colonization of root cortical cells by arbuscular mycorrhizal fungi leads to marked cytological changes of plastids and mitochondria. Plastids in particular are forming tubular extensions partially connecting individual organelles in a network-like way. These cytological changes correspond to an increased need for plastid and mitochondrial products during establishment and functioning of the symbiosis. The analysis of metabolite and transcript levels in mycorrhizal and nonmycorrhizal roots from Medicago truncatula revealed concomitant changes regarding a number of metabolic pathways. Our results indicate the activation of the mitochondrial tricarboxylic acid cycle and of plastid biosynthetic pathways producing fatty acids, amino acids, and apocarotenoids. These observations provide a general overview of structural and metabolic changes of plastids and mitochondria during colonization of root cortical cells by arbuscular mycorrhizal fungi.
Publikation

Liu, S.; Chen, K.; Schliemann, W.; Strack, D.; Isolation and identification of arctiin and arctigenin in leaves of burdock (Arctium lappa L.) by polyamide column chromatography in combination with HPLC-ESI[sol ]MS Phytochem. Anal. 16, 86-89, (2005) DOI: 10.1002/pca.816

A simple method involving polyamide column chromatography in combination with HPLC‐PAD and HPLC‐ESI[sol ]MS for isolating and identifying two kinds of lignans, arctiin and arctigenin, in the leaves of burdock (Arctium lappa L.) has been established. After extraction of burdock leaves with 80% methanol, the aqueous phase of crude extracts was partitioned between water and chloroform and the aqueous phase was fractionated on a polyamide glass column. The fraction, eluting with 100% methanol, was concentrated and gave a white precipitate at 4°C from which two main compounds were purified by semi‐preparative HPLC. In comparison with the UV and ESI‐MS spectra and the HPLC retention time of authentic standards, the compounds were determined to be arctiin and arctigenin. The extraction[sol ]separation technique was validated using an internal standard method. Copyright © 2005 John Wiley & Sons, Ltd.
Publikation

Kramell, R.; Schmidt, J.; Herrmann, G.; Schliemann, W.; N-(Jasmonoyl)tyrosine-Derived Compounds from Flowers of Broad Beans (Vicia faba) J. Nat. Prod. 68, 1345-1349, (2005) DOI: 10.1021/np0501482

Two new amide-linked conjugates of jasmonic acid, N-[(3R,7R)-(−)-jasmonoyl]-(S)-dopa (3) and N-[(3R,7R)-(−)-jasmonoyl]-dopamine (5), were isolated in addition to the known compound N-[(3R,7R)-(−)-jasmonoyl]-(S)-tyrosine (2) from the methanolic extract of flowers of broad bean (Vicia faba). Their structures were proposed on the basis of spectroscopic data (LC-MS/MS) and chromatographic properties on reversed and chiral phases and confirmed by partial syntheses. Furthermore, tyrosine conjugates of two cucurbic acid isomers (7, 8) were detected and characterized by LC-MS. Crude enzyme preparations from flowers of V. faba hydroxylated both (±)-2 and N-[(3R,7R/3S,7S)-(−)-jasmonoyl]tyramine [(±)-4] to (±)-3 and (±)-5, respectively, suggesting a possible biosynthetic relationship. In addition, a commercial tyrosinase (mushroom) and a tyrosinase-containing extract from hairy roots of red beet exhibited the same catalytic properties, but with different substrate specificities. The conjugates (±)-2, (±)-3, (±)-4, and (±)-5 exhibited in a bioassay low activity to elicit alkaloid formation in comparison to free (±)-jasmonic acid [(±)-1].
Publikation

Isayenkov, S.; Mrosk, C.; Stenzel, I.; Strack, D.; Hause, B.; Suppression of Allene Oxide Cyclase in Hairy Roots of Medicago truncatula Reduces Jasmonate Levels and the Degree of Mycorrhization with Glomus intraradices Plant Physiol. 139, 1401-1410, (2005) DOI: 10.1104/pp.105.069054

During the symbiotic interaction between Medicago truncatula and the arbuscular mycorrhizal (AM) fungus Glomus intraradices, an endogenous increase in jasmonic acid (JA) occurs. Two full-length cDNAs coding for the JA-biosynthetic enzyme allene oxide cyclase (AOC) from M. truncatula, designated as MtAOC1 and MtAOC2, were cloned and characterized. The AOC protein was localized in plastids and found to occur constitutively in all vascular tissues of M. truncatula. In leaves and roots, MtAOCs are expressed upon JA application. Enhanced expression was also observed during mycorrhization with G. intraradices. A partial suppression of MtAOC expression was achieved in roots following transformation with Agrobacterium rhizogenes harboring the MtAOC1 cDNA in the antisense direction under control of the cauliflower mosaic virus 35S promoter. In comparison to samples transformed with 35S∷uidA, roots with suppressed MtAOC1 expression exhibited lower JA levels and a remarkable delay in the process of colonization with G. intraradices. Both the mycorrhization rate, quantified by fungal rRNA, and the arbuscule formation, analyzed by the expression level of the AM-specific gene MtPT4, were affected. Staining of fungal material in roots with suppressed MtAOC1 revealed a decreased number of arbuscules, but these did not exhibit an altered structure. Our results indicate a crucial role for JA in the establishment of AM symbiosis.
Publikation

Hüsken, A.; Baumert, A.; Milkowski, C.; Becker, H. C.; Strack, D.; Möllers, C.; Resveratrol glucoside (Piceid) synthesis in seeds of transgenic oilseed rape (Brassica napus L.) Theor. Appl. Genet. 111, 1553-1562, (2005) DOI: 10.1007/s00122-005-0085-1

Resveratrol is a phytoalexin produced in various plants like wine, peanut or pine in response to fungal infection or UV irradiation, but it is absent in members of the Brassicaceae. Moreover, resveratrol and its glucoside (piceid) are considered to have beneficial effects on human health, known to reduce heart disease, arteriosclerosis and cancer mortality. Therefore, the introduction of the gene encoding stilbene synthase for resveratrol production in rapeseed is a tempting approach to improve the quality of rapeseed products. The stilbene synthase gene isolated from grapevine (Vitis vinifera L.) was cloned under control of the seed-specific napin promotor and introduced into rapeseed (Brassica napus L.) by Agrobacterium-mediated co-transformation together with a ds-RNA-interference construct deduced from the sequence of the key enzyme for sinapate ester biosynthesis, UDP-glucose:sinapate glucosyltransferase (BnSGT1), assuming that the suppression of the sinapate ester biosynthesis may increase the resveratrol production in seeds through the increased availability of the precursor 4-coumarate. Resveratrol glucoside (piceid) was produced at levels up to 361 μg/g in the seeds of the primary transformants. This value exceeded by far piceid amounts reported from B. napus expressing VST1 in the wild type sinapine background. There was no significant difference in other important agronomic traits, like oil, protein, fatty acid and glucosinolate content in comparison to the control plants. In the third seed generation, up to 616 μg/g piceid was found in the seeds of a homozygous T3-plant with a single transgene copy integrated. The sinapate ester content in this homozygous T3-plant was reduced from 7.43 to 2.40 mg/g. These results demonstrate how the creation of a novel metabolic sink could divert the synthesis towards the production of piceid rather than sinapate ester, thereby increasing the value of oilseed products.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
IPB Mainnav Search