Bernd Schneider

Thompson Institute, Итак, New York, United States

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Publications (247)658.16 Total impact

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    Full-text · Article · Feb 2016 · Pharmaceutical Biology
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    ABSTRACT: 2-Hydroxy-8-(4-hydroxyphenyl)-1H-phenalen-1-one (1), the first reported 8-phenylphenalenone from the roots of Eichhornia crassipes (water hyacinth), was synthesized starting from 2-methoxynaphthalene in eleven steps and with an overall yield of 2%. A cascade Friedel-Crafts/Michael annulation reaction between acryloyl chloride and 2-methoxynaphthalene afforded 9-methoxyperinaphthanone which, after transformation to 9-methoxy-2-(4-methoxyphenyl)-1H-phenalen-1-one by means of standard Suzuki-Miyaura methodology, was subjected to a reductive carbonyl transposition to afford 8-(4-methoxyphenyl)perinaphthanone. Dehydrogenation, epoxidation and demethylation of the latter afforded 1.
    No preview · Article · Jan 2016 · The Journal of Organic Chemistry
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    ABSTRACT: Nudicaulins are a group of indole alkaloid glycosides responsible for the color of yellow petals of Papaver nudicaule (Iceland poppy). The unique aglycone scaffold of these alkaloids attracted our interest as one of the most uncommon flavonoid-indole hybrid structures that occur in nature. Stable isotope labeling experiments using sliced petals identified free indole, but not tryptamine or L-tryptophan, as one of the two key biosynthetic precursors of the nudicaulin aglycone. Pelargonidin was identified as the second key precursor, contributing the polyphenolic unit to the nudicaulin molecule. This finding was inferred from the temporary accumulation of pelargonidin glycosides in the petals during flower bud development and a drop at the point in time when nudicaulin levels start to increase. The precursor-directed incorporation of cyanidin into a new 3'-hydroxynudicaulin strongly supports the hypothesis that anthocyanins are involved in the biosynthesis of nudicaulins.
    Full-text · Article · Dec 2015 · ChemBioChem
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    ABSTRACT: Infrared-guided chromatographic fractionation of sesquiterpene lactones from the extracts of Cousinia aitchisonii and Cousinia concolor led to the isolation of five pure compounds. A new sesquiterpene lactone, namely, aitchisonolide, and two known sesquiterpene lactones (desoxyjanerin and rhaserolide) were isolated from C. aitchisonii and two known lignans (arctiin and arctigenin) from C. concolor. The structures of these compounds were elucidated by one-dimensional and two-dimensional nuclear magnetic resonance techniques, as well as high-resolution mass spectrometry. The purified and characterized compounds were subjected to cytotoxicity assay. The sesquiterpene lactones desoxyjanerin and rhaserolide showed significant cytotoxic activities against five different cancer cell lines and the normal human embryonic kidney cell line. Rhaserolide was chosen to evaluate the possible mechanism of action. Western blot analysis revealed that rhaserolide could induce apoptosis in Jurkat cells via the activation of c-Jun n-terminal kinase phosphorylation. Copyright © 2015 John Wiley & Sons, Ltd.
    No preview · Article · Nov 2015 · Phytotherapy Research
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    ABSTRACT: The acyclic monoterpene alcohol linalool is one of the most frequently encountered volatile compounds in floral scents. Various linalool oxides are usually emitted along with linalool, some of which are cyclic, such as the furanoid lilac compounds. Recent work has revealed the coexistence of two flower-expressed linalool synthases that produce the (S)- or (R)-linalool enantiomers and the involvement of two P450 enzymes in the linalool oxidation in the flowers of Arabidopsis thaliana. Partially redundant enzymes may also contribute to floral linalool metabolism. Here, we provide evidence that CYP76C1 is a multifunctional enzyme that catalyzes a cascade of oxidation reactions and is the major linalool metabolizing oxygenase in Arabidopsis flowers. Based on the activity of the recombinant enzyme and mutant analyses, we demonstrate its prominent role in the formation of most of the linalool oxides identified in vivo, both as volatiles and soluble conjugated compounds, including 8-hydroxy, 8-oxo, and 8-COOH-linalool, as well as lilac aldehydes and alcohols. Analysis of insect behavior on CYP76C1 mutants and in response to linalool and its oxygenated derivatives demonstrates that CYP76C1-dependent modulation of linalool emission and production of linalool oxides contribute to reduced floral attraction and favor protection against visitors and pests.
    Full-text · Article · Oct 2015 · The Plant Cell
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    Oliver Kayser · Nizar Happyana · Bernd Schneider

    Full-text · Dataset · Oct 2015
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    ABSTRACT: The evolutionary plant-herbivore arms race sometimes gives rise to remarkably unique adaptation strategies. Here we report one such strategy in the lepidopteran herbivore Manduca sexta against its hostplant Nicotiana attenuataa € s major phytotoxins, 17-hydroxygeranyllinalool diterpene glycoside, lyciumoside IV and its malonylated forms. We show that alkalinity of larval regurgitant non-enzymatically demalonylates the malonylated forms to lyciumoside IV. Lyciumoside IV is then detoxified in the midgut by β-glucosidase 1-catalysed deglycosylation, which is unusual, as typically the deglycosylation of glycosylated phytochemicals by insects results in the opposite: toxin activation. Suppression of deglucosylation by silencing larval β-glucosidase 1 by plant-mediated RNAi causes moulting impairments and mortality. In the native habitat of N. attenuata, β-glucosidase 1 silencing also increases larval unpalatability to native predatory spiders, suggesting that the defensive co-option of lyciumoside IV may be ecologically advantageous. We infer that M. sexta detoxifies this allelochemical to avoid its deleterious effects, rather than co-opting it against predators. © 2015 Macmillan Publishers Limited. All rights reserved.
    Full-text · Article · Oct 2015 · Nature Communications
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    ABSTRACT: Apple proliferation (AP) is caused by a psyllid‐transmitted phytoplasma and is one of the most economically important diseases on apple in Europe. AP was first reported in northern Italy and in the following years from many European countries. Previous research on phytoplasma‐ induced diseases of rosaceous fruit trees (mainly AP, pear decline and European stone fruit yellows), exhibits strong evidence that phloem injuries play a central and probably universal role in phytoplasma pathogenicity. The effect of phytoplasma infections on phloem function and the resulting diseases received little attention in the past. Phytoplasma infection severely impairs assimilate translocation in host plants and might be responsible for massive changes in phloem physiology including signalling components. As shown for other phytoplasma species, infection brings about Ca2+ influx into sieve tubes, leading to sieve‐tube occlusion by callose deposition or protein plugging, which is assumed also for AP phytoplasma. Effectors may cause gating of sieve‐element Ca2+ channels leading to sievetube occlusion with presumptive dramatic effects on phytoplasma spread, photoassimilate distribution and the whole phloem physiology. However, there is indication that phloem loading is affected by phytoplasma infection. As sieve elements need a permanent input of energy to ensure their viability, sugar metabolism and the associate energy production of the companion cells have a dramatic impact on the physiological fitness of phloem function. It is presumptive that signalling substances are produced prior sieve‐element occlusion to ensure the spread throughout the plant body. Analyses of diverse phytohormones in response to challenge with AP phytoplasma show a strong increase of salicylic acid accompanied by a decrease of jasmonic acid. This supports the idea that phytohormones have a role in plant defence signalling against phytoplasma infection. It is a matter of debate whether mechanisms involved in phloem impairment could differ between pathosystems and vary with the plant susceptibility to infection.
    Full-text · Article · Oct 2015 · Endocytobiosis and Cell Research
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    William Hidalgo · Marco Kai · Bernd Schneider
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    ABSTRACT: In vitro root cultures of Anigozanthos preissii and Wachendorfia thyrsiflora (Haemodoraceae) are suitable biological systems for studying the biosynthesis of phenylphenalenones. Here we report how we used these root cultures to investigate precursor-product relationships between phenylpropanoids and phenylphenalenones whose phenyl rings share identical substitution patterns. Four phenylpropanoic acids, including ferulic acid and the unusual 4-methoxycinnamic acid, were used in (13)C-labeled form as substrates to study their incorporation into phenylphenalenones. In addition to the previously reported 2-hydroxy-9-(4'-hydroxy-3'-methoxyphenyl)-1H-phenalen-1-one (trivial name musanolone F), 2-hydroxy-9-(4'-methoxyphenyl)-1H-phenalen-1-one (proposed trivial name 4'-methoxyanigorufone) was found as a biosynthetic product in A. preissii. The carbon skeleton of 4'-methoxycinnamic acid was biosynthetically incorporated as an intact unit including its 4'-O-methyl substituent at the lateral phenyl ring. 4'-Methoxyanigorufone is reported here for the first time as a natural product. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · Sep 2015 · Phytochemistry
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    ABSTRACT: Phenylphenalenones, polycyclic aromatic natural products from some monocotyledonous plants, are known as phytoalexins in banana (Musa spp.). In this study, (1) H NMR-based metabolomics along with liquid chromatography and mass spectrometry were used to explore the chemical responses of the susceptible 'Williams' and the resistant 'Khai Thong Ruang' Musa varieties to the ascomycete fungus Mycosphaerella fijiensis, the agent of the Black Leaf Sigatoka Disease. Principal component analysis discriminated strongly between infected and non-infected plant tissue, mainly due to specialized metabolism induced in response to the fungus. Phenylphenalenones are among the major induced compounds, and the resistance level of the plants was correlated with the progress of the disease. However, a virulent strain of M. fijiensis was able to overcome plant resistance by converting phenylphenalenones to sulfate conjugates. Here we report the first metabolic detoxification of fungitoxic phenylphenalenones to evade the chemical defense of Musa plants. This article is protected by copyright. All rights reserved.
    No preview · Article · Aug 2015 · Plant Cell and Environment
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    ABSTRACT: The ethanol solvolysis of 3-methoxy-14,17-etheno-16α-nitroestra-1,3,5(10)-trien-17β-yl acetate in the presence of NaHCO3 was studied by means of real-time NMR experiments, LC-SPE-NMR, and LC-MS. The pathway to form 3-methoxy-2'-oxopyrrolidino-[4',5':14β,15β]-estra-1,3,5(10)-trien-17-one was disclosed. The intermediacy of nitrile oxide and alkoxynitrone was postulated based on the analysis of the reaction products. The proposed mechanism of cleaving the bridge in the nitro compound is legal for the formation of N-acetoxylactams, nitriles, isoxazoles and isoxazolines. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Aug 2015 · Steroids
  • Katharina Zenger · Sara Agnolet · Bernd Schneider · Birgit Kraus
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    ABSTRACT: The in vitro metabolism of flavokawain A, B and C (FKA, FKB, FKC), methoxylated chalcones from Piper methysticum, was examined using human liver microsomes. Phase I and phase II (glucuronidation) metabolism as well as combined phase I+II metabolism were studied. For identification and structure elucidation of microsomal metabolites, LC-HRESIMS and NMR techniques were applied. Major phase I metabolites were generated by demethylation in position C-4 or C-4' and hydroxylation predominantly in position C-4, yielding FKC as phase I metabolite of FKA and FKB, helichrysetin as metabolite of FKA and FKC, and cardamonin as metabolite of FKC. To an even greater extent, flavokawains were metabolized in presence of uridine diphosphate (UDP) glucuronic acid by microsomal UDP-glucuronosyl transferases. For all flavokawains, monoglucuronides (FKA-2'-O-glucuronide, FKB-2'-O-glucuronide, FKC-2'-O-glucuronide, FKC-4-O-glucuronide) were found as major phase II metabolites. The dominance of generated glucuronides suggests a role of conjugated chalcones as potential active compounds in vivo.
    No preview · Article · Jun 2015 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Evaluation of 4-phenylphenalenones and structural analogues against the fungal pathogen Mycosphaerella fijiensis (causal agent of black sigatoka disease in bananas) under light-controlled conditions uncovered some key structural features for the design of photodynamic compounds. SAR analysis revealed the importance of a chromophoric aryl-ketone and a "steroidomimetic" structural motif in the activity of the assayed compounds. The results pointed to the evaluation of 1,2-dihydro-3H-naphtho[2',1':3,4]cyclohepta[1,2-b]furan-3-one which displayed an activity in the range of propiconazole but with photodynamic behavior. The present work demonstrates that 1,2-dihydro-3H-naphtho[2',1':3,4]cyclohepta[1,2-b]heterocyclic-3-one derivatives can be used as potential lead compounds for the development of fungicides which relies on a dual mode of action. This article is protected by copyright. All rights reserved.
    Full-text · Article · Jun 2015 · Pest Management Science
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    ABSTRACT: Arabidopsis PENETRATION (PEN) genes quantitatively contribute to the execution of different forms of plant immunity upon challenge with diverse leaf pathogens. PEN3 encodes a plasma membrane-resident pleiotropic drug resistance-type ATP-binding cassette transporter and is thought to act in a pathogen-inducible and PEN2 myrosinase-dependent metabolic pathway in extracellular defense. This metabolic pathway directs the intracellular biosynthesis and activation of tryptophan (Trp)-derived indole glucosinolates for subsequent PEN3-mediated efflux across the plasma membrane at pathogen contact sites. However, PEN3 functions also in abiotic stress responses to cadmium and indole-3-butyric acid (IBA)-mediated auxin homeostasis in roots, raising the possibility that PEN3 exports multiple functionally unrelated substrates. Here we describe the isolation of a pen3 allele, designated pen3-5, which encodes a dysfunctional protein that accumulates in planta like wild-type PEN3. The specific mutation in pen3-5 uncouples PEN3 functions in IBA-stimulated root growth modulation, flg22-induced callose deposition and pathogen-inducible salicylic acid accumulation from PEN3 activity in extracellular defense, indicating the engagement of multiple PEN3 substrates in different PEN3-dependent biological processes. We identified 4-O-β-D-glucosyl-indol-3-yl formamide (4OGlcI3F) as a pathogen-inducible Trp-derived compound that over-accumulates in pen3 leaf tissue and whose biosynthesis is dependent on an intact PEN2 metabolic pathway. We propose that a precursor(s) of 4OGlcI3F is the PEN3 substrate in extracellular pathogen defense. These precursors, the shared indole core present in IBA and 4OGlcI3F, and allele-specific uncoupling of a subset of PEN3 functions, suggest that PEN3 transports distinct indole-type metabolites in distinct biological processes. Copyright © 2015, Plant Physiology.
    No preview · Article · May 2015 · Plant physiology
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    ABSTRACT: The banana epidermis and in particular their stomata are conducive sites for the penetration of pathogenic fungi which can severely limit global banana production. The red pseudostem of the ornamental banana Musa acuminata ssp. zebrina cv. 'Rowe Red' was used to study the chemical constituents of the epidermal cell layer using matrix-free laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric imaging (LDI-FT-ICR-MSI). The high resolution of this technique allowed phenylphenalenone-type compounds to be located in single plant cells. Some of these secondary metabolites were identified as constitutive compounds and found in specialized epidermal cells in banana pseudostem tissue. Especially the red paracytic stomata revealed higher signal intensities of certain phenylphenalenones than normal epidermis cells. The ease of detection of polycyclic aromatic compounds on the cellular level is discussed with regard to future investigations of plant-pathogen interactions. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · May 2015 · Phytochemistry
  • Felix Feistel · Christian Paetz · Sybille Lorenz · Bernd Schneider
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    ABSTRACT: The absolute configuration of salicortin, HCH-salicortin and tremulacin, isolated from leaves of Populus trichocarpa × deltoides Beaupré, was determined by comparing spectroscopic data of these compounds with those of idescarpin, isolated from leaves of Idesia polycarpa. All compounds were characterized by nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, and circular dichroism spectroscopy. It was found that the hydroxy cyclohexenonoyl (HCH) moiety in all compounds is (S)-configured. In addition, it was shown that leaves of Idesia polycarpa contain high amounts of (-)-idescarpin (1.1%, based on dry weight).
    No preview · Article · Apr 2015 · Molecules
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    Full-text · Dataset · Mar 2015
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    Full-text · Dataset · Mar 2015
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    ABSTRACT: The secondary metabolites in the roots, leaves and flowers of the common dandelion (Taraxacum officinale agg.) have been studied in detail. However, little is known about the specific constituents of the plant's highly specialized laticifer cells. Using a combination of liquid and gas chromatography, mass spectrometry and nuclear magnetic resonance spectrometry, we identified and quantified the major secondary metabolites in the latex of different organs across different growth stages in three genotypes, and tested the activity of the metabolites against the generalist root herbivore Diabrotica balteata. We found that common dandelion latex is dominated by three classes of secondary metabolites: phenolic inositol esters (PIEs), triterpene acetates (TritAc) and the sesquiterpene lactone taraxinic acid β-d-glucopyranosyl ester (TA-G). Purification and absolute quantification revealed concentrations in the upper mgg(-1) range for all compound classes with up to 6% PIEs, 5% TritAc and 7% TA-G per gram latex fresh weight. Contrary to typical secondary metabolite patterns, concentrations of all three classes increased with plant age. The highest concentrations were measured in the main root. PIE profiles differed both quantitatively and qualitatively between plant genotypes, whereas TritAc and TA-G differed only quantitatively. Metabolite concentrations were positively correlated within and between the different compound classes, indicating tight biosynthetic co-regulation. Latex metabolite extracts strongly repelled D. balteata larvae, suggesting that the latex constituents are biologically active. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Feb 2015 · Phytochemistry
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    ABSTRACT: Plant pathogenic phytoplasmas found in wild grasses in East Africa could pose a serious threat to the cultivation of Napier grass, Pennisetum purpureum, the most important livestock fodder in the region. To asses this threat, leaves from plants of 33 grass species were sampled from Mbita, Bungoma and Busia districts in western Kenya, Tarime district in northern Tanzania and Busia and Bugiri districts in the eastern Uganda to determine which species host phytoplasmas, their identity and their relationship with disease symptoms. Phytoplasmas were detected using universal primers based on conserved phytoplasma-specific 16S rDNA sequence motives infrom 11 grass species collected. Sequence and phylogenetic analysis revealed the presence of Napier grass stunt (NGS)- related phytoplasmas in 11 grass species, ‘Candidatus Phytoplasma cynodontis’ in three, and goosegrass white leaf (GGWL) phytoplasma in two wild grass species. This study showed that the geographical distribution, diversity of phytoplasmas and their grass host species in East Africa is greater than antecedently thought and that typical disease symptoms including white leaf or stunting alone are not always reliable indicators of the presence of phytoplasma. It also shows the need to identify insect vectors responsible for phytoplasma transmission from native grasses to Napier grass or other cereals present in the region.
    Full-text · Article · Feb 2015 · Plant Disease

Publication Stats

4k Citations
658.16 Total Impact Points


  • 2015
    • Thompson Institute
      Итак, New York, United States
  • 2007-2015
    • Max Planck Institute for Biogeochemistry Jena
      Jena, Thuringia, Germany
    • Federal Agency for Agriculture and Food (Germany)
      Berlín, Berlin, Germany
  • 1998-2015
    • Max Planck Institute for Chemical Ecology
      • • Department of Biochemistry
      • • Department of Molecular Ecology
      • • Department of Bioorganic Chemistry
      Jena, Thuringia, Germany
  • 2014
    • Universität Ulm
      • Institute of Natural Medicine and Clinical Pharmacology
      Ulm, Baden-Württemberg, Germany
  • 2008-2014
    • Julius Kühn-Institut
      • Institute for Plant Protection in Fruit Crops and Viticulture
      Stadt Quedlinburg, Saxony-Anhalt, Germany
    • University of Antioquia
      • Instituto de Química
      Medellín, Antioquia, Colombia
  • 2010
    • Kunming University of Science and Technology
      Yün-nan, Yunnan, China
  • 2008-2010
    • Mashhad University of Medical Sciences
      • Department of Pharmacognosy
      Mashad, Razavi Khorasan, Iran
  • 2005
    • Max Planck Institute for Plant Breeding Research
      • Department of Plant Microbe Interactions
      Köln, North Rhine-Westphalia, Germany
  • 2002
    • Martin Luther University Halle-Wittenberg
      • Institute of Chemistry
      Halle-on-the-Saale, Saxony-Anhalt, Germany
    • National Academy of Sciences of Belarus
      • Institute of Bioorganic Chemistry
      Myenyesk, Minsk, Belarus