zur Suche springenzur Navigation springenzum Inhalt springen

Publikationen - Natur- und Wirkstoffchemie

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 1 bis 10 von 19.

Publikation

Stehle, F.; Götsch, F.; Wray, V.; Schmidt, J.; Strack, D.; Brandt, W.; Snap-shot of Serine Carboxypeptidase-like Acyltransferase Evolution: The Loss of Conserved Disulphide Bridge is Responsible for the Completion of Neo-functionalization J. Phylogenet. Evol. Biol. 1, 115, (2013) DOI: 10.4172/2329-9002.1000115

In this work, it is shown that the At2g23010 gene product encodes 1-O-sinapoyl-β-glucose:1-O-sinapoyl-β-glucose sinapoyltransferase (SST). In contrast to all other functional characterized acyltransferases, the SST protein is highly specific towards this reaction only, and the substrate specificity was correlated to one amino acid substitution. Detailed sequence analysis revealed the lack of the disulphide bond S1 (C78 and C323 in the SMT (sinapoylglucose:malate sinapoyltransferase), that is in SST C80 and D327). The reconstitution of this disulphide bond led to an enzyme accepting many different substrates including disaccharides. Interestingly, the overall changes within the model structures are not very dramatic, but nevertheless, the enzyme models provide some explanations for the broadened substrate specificity: the reconstitution of the disulphide bond provoked more space within the substrate binding pocket simultaneously avoiding electrostatic repulsion. As the SST sequence of A. lyrata also showed the same mutation, the loss of the disulphide bond should has arisen at least 10 mya ago. A Ka/Ks ratio ≤ 1 supports the hypothesis that the loss of this disulphide bond was rather a specification towards a certain reaction than the beginning of a gene death. At the same time, this is also associated with the fixation in the genome.
Publikation

Wolfram, K.; Schmidt, J.; Wray, V.; Milkowski, C.; Schliemann, W.; Strack, D.; Profiling of phenylpropanoids in transgenic low-sinapine oilseed rape (Brassica napus) Phytochemistry 71, 1076-1084, (2010) DOI: 10.1016/j.phytochem.2010.04.007

A dsRNAi approach silencing a key enzyme of sinapate ester biosynthesis (UDP-glucose:sinapate glucosyltransferase, encoded by the UGT84A9 gene) in oilseed rape (Brassica napus) seeds was performed to reduce the anti-nutritive properties of the seeds by lowering the content of the major seed component sinapine (sinapoylcholine) and various minor sinapate esters. The transgenic seeds have been produced so far to the T6 generation and revealed a steady suppression of sinapate ester accumulation. HPLC analysis of the wild-type and transgenic seeds revealed, as in the previous generations, marked alterations of the sinapate ester pattern of the transformed seeds. Besides strong reduction of the amount of the known sinapate esters, HPLC analysis revealed unexpectedly the appearance of several minor hitherto unknown rapeseed constituents. These compounds were isolated and identified by mass spectrometric and NMR spectroscopic analyses. Structures of 11 components were elucidated to be 4-O-glucosides of syringate, caffeyl alcohol and its 7,8-dihydro derivative as well as of sinapate and sinapine, along with sinapoylated kaempferol glycosides, a hexoside of a cyclic spermidine alkaloid and a sinapine derivative with an ether-bridge to a C6–C3-unit. These results indicate a strong impact of the transgenic approach on the metabolic network of phenylpropanoids in B. napus seeds. Silencing of UGT84A9 gene expression disrupt the metabolic flow through sinapoylglucose and alters the amounts and nature of the phenylpropanoid endproducts.
Publikation

Schliemann, W.; Kolbe, B.; Schmidt, J.; Nimtz, M.; Wray, V.; Accumulation of apocarotenoids in mycorrhizal roots of leek (Allium porrum) Phytochemistry 69, 1680-1688, (2008) DOI: 10.1016/j.phytochem.2008.02.015

Colonization of the roots of leek (Allium porrum L.) by the arbuscular mycorrhizal fungus Glomus intraradices induced the formation of apocarotenoids, whose accumulation has been studied over a period of 25 weeks. Whereas the increase in the levels of the dominating cyclohexenone derivatives resembles the enhancement of root length colonization, the content of mycorradicin derivatives remains relatively low throughout. Structural analysis of the cyclohexenone derivatives by mass spectrometry and NMR spectroscopy showed that they are mono- and diglycosides of 13-hydroxyblumenol C and blumenol C acylated with 3-hydroxy-3-methyl-glutaric and/or malonic acid. Along with the isolation of three known compounds five others are shown to be hitherto unknown members of the fast-growing family of mycorrhiza-induced cyclohexenone conjugates.
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

Baumert, A.; Milkowski, C.; Schmidt, J.; Nimtz, M.; Wray, V.; Strack, D.; Formation of a complex pattern of sinapate esters in Brassica napus seeds, catalyzed by enzymes of a serine carboxypeptidase-like acyltransferase family? Phytochemistry 66, 1334-1345, (2005) DOI: 10.1016/j.phytochem.2005.02.031

Members of the Brassicaceae accumulate complex patterns of sinapate esters, as shown in this communication with seeds of oilseed rape (Brassica napus). Fifteen seed constituents were isolated and identified by a combination of high-field NMR spectroscopy and high resolution electrospray ionisation mass spectrometry. These include glucose, gentiobiose and kaempferol glycoside esters as well as sinapine (sinapoylcholine), sinapoylmalate and an unusual cyclic spermidine amide. One of the glucose esters (1,6-di-O-sinapoylglucose), two gentiobiose esters (1-O-caffeoylgentiobiose and 1,2,6′-tri-O-sinapoylgentiobiose) and two kaempferol conjugates [4′-(6-O-sinapoylglucoside)-3,7-di-O-glucoside and 3-O-sophoroside-7-O-(2-O-sinapoylglucoside)] seem to be new plant products. Serine carboxypeptidase-like (SCPL) acyltransferases catalyze the formation of sinapine and sinapoylmalate accepting 1-O-β-acetal esters (1-O-β-glucose esters) as acyl donors. To address the question whether the formation of other components of the complex pattern of the sinapate esters in B. napus seeds is catalyzed via 1-O-sinapoyl-β-glucose, we performed a seed-specific dsRNAi-based suppression of the sinapate glucosyltransferase gene (BnSGT1) expression. In seeds of BnSGT1-suppressing plants the amount of sinapoylglucose decreased below the HPLC detection limit resulting in turn in the disappearance or marked decrease of all the other sinapate esters, indicating that formation of the complex pattern of these esters in B. napus seeds is dependent on sinapoylglucose. This gives rise to the assumption that enzymes of an SCPL acyltransferase family catalyze the appropriate transfer reactions to synthesize the accumulating esters.
Publikation

Münzenberger, B.; Hammer, E.; Wray, V.; Schauer, F.; Schmidt, J.; Strack, D.; Detoxification of ferulic acid by ectomycorrhizal fungi Mycorrhiza 13, 117-121, (2003) DOI: 10.1007/s00572-003-0226-9

The ectomycorrhizal fungi Laccaria amethystina and Lactarius deterrimus grown in liquid culture were used to study the fate of added ferulic acid. Laccaria amethystina degraded ferulic acid to the major metabolite vanillic acid. The intermediate vanillin was not detected. Lactarius deterrimus showed a completely different detoxification pattern. Two dimers and one trimer of ferulic acid could be identified as polymerization products of this fungus. A bioassay of the possible biological activities of ferulic acid and vanillic acid on these fungi revealed that vanillic acid was less toxic than ferulic acid for Laccaria amethystina but that both phenolic acids were toxic for Lactarius deterrimus. The results are discussed with respect to ectomycorrhizal fungal growth in the organic layer of forest soils and between living root cells of ectomycorrhizas.
Publikation

Landtag, J.; Baumert, A.; Degenkolb, T.; Schmidt, J.; Wray, V.; Scheel, D.; Strack, D.; Rosahl, S.; Accumulation of tyrosol glucoside in transgenic potato plants expressing a parsley tyrosine decarboxylase Phytochemistry 60, 683-689, (2002) DOI: 10.1016/S0031-9422(02)00161-9

As part of the response to pathogen infection, potato plants accumulate soluble and cell wall-bound phenolics such as hydroxycinnamic acid tyramine amides. Since incorporation of these compounds into the cell wall leads to a fortified barrier against pathogens, raising the amounts of hydroxycinnamic acid tyramine amides might positively affect the resistance response. To this end, we set out to increase the amount of tyramine, one of the substrates of the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction, by placing a cDNA encoding a pathogen-induced tyrosine decarboxylase from parsley under the control of the 35S promoter and introducing the construct into potato plants via Agrobacterium tumefaciens-mediated transformation. While no alterations were observed in the pattern and quantity of cell wall-bound phenolic compounds in transgenic plants, the soluble fraction contained several new compounds. The major one was isolated and identified as tyrosol glucoside by liquid chromatography–electrospray ionization–high resolution mass spectrometry and NMR analyses. Our results indicate that expression of a tyrosine decarboxylase in potato does not channel tyramine into the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction but rather unexpectedly, into a different pathway leading to the formation of a potential storage compound.Expression of a parsley tyrosine decarboxylase in potato unexpectedly channels tyramine into a pathway leading to the formation of tyrosol glucoside.
Publikation

Fester, T.; Hause, B.; Schmidt, D.; Halfmann, K.; Schmidt, J.; Wray, V.; Hause, G.; Strack, D.; Occurrence and Localization of Apocarotenoids in Arbuscular Mycorrhizal Plant Roots Plant Cell Physiol. 43, 256-265, (2002) DOI: 10.1093/pcp/pcf029

The core structure of the yellow pigment from arbuscular mycorrhizal (AM) maize roots contains the apocarotenoids mycorradicin (an acyclic C14 polyene) and blumenol C cellobioside (a C13 cyclohexenone diglucoside). The pigment seems to be a mixture of different esterification products of these apocarotenoids. It is insoluble in water and accumulates as hydrophobic droplets in the vacuoles of root cortical cells. Screening 58 species from 36 different plant families, we detected mycorradicin in mycorrhizal roots of all Liliopsida analyzed and of a considerable number of Rosopsida, but also species were found in which mycorradicin was undetectable in mycorrhizal roots. Kinetic experiments and microscopic analyses indicate that accumulation of the yellow pigment is correlated with the concomitant degradation of arbuscules and the extensive plastid network covering these haustorium-like fungal structures. The role of the apocarotenoids in mycorrhizal roots is still unknown. The potential C40 carotenoid precursors, however, are more likely to be of functional importance in the development and functioning of arbuscules.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
IPB Mainnav Search