Bernd Schneider

Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany

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Publications (237)646.44 Total impact

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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.
    Phytochemistry 05/2015; DOI:10.1016/j.phytochem.2015.04.010 · 3.35 Impact Factor
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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.
    Phytochemistry 02/2015; DOI:10.1016/j.phytochem.2015.01.003 · 3.35 Impact Factor
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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).
    Molecules 01/2015; 20(4):5566-73. DOI:10.3390/molecules20045566 · 2.10 Impact Factor
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    ABSTRACT: Ethyl 3-(6,6-ethylenedioxy-2α,3α-isopropylidenedioxy-17-oxo-5α-androstan-14α-yl)propanoate, the key intermediate product in the synthesis of brassinosteroids modified in the D ring, was synthesized from 6,6-ethylenedioxy-2α,3α-isopropylidenedioxy-5α-androsta-14,16-dien-17-yl acetate via reaction sequence including Diels-Alder cycloaddition with phenyl vinyl sulfone, dihydroxylation, Malaprade diol cleavage, and selective Horner-Wadsworth-Emmons olefination.
    Russian Journal of Organic Chemistry 01/2015; 51(1):78-85. DOI:10.1134/S1070428015010133 · 0.68 Impact Factor
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    ABSTRACT: Flaxseed is an important source of lignans and ω-3 fatty acids, compounds which present interest in human health with many applications in food industry. It is therefore necessary to precisely know the metabolite content in flaxseed. A metabolomic approach using NMR was developed to achieve this goal. Due to particular characteristics of flaxseed (high level in oil, high amount in mucilage, and integration of the phenolics into a macromolecule), the extraction procedure had first to be optimized using an experimental design, based on the extraction time, in a water bath or an ultrasound bath, alkaline treatment, defatting, and centrifugation temperature. This methodology was then applied to several flaxseed varieties classified in function of their content in ω-3 fatty acid. The main differences in semi-polar metabolites between these varieties concern compounds of the phenylpropanoid pathway. Hydroxycinnamic acid glucoside and lignan content increase when ω-3 fatty acid content decrease whereas flavonoid content increase in the same way of ω-3 fatty acids.
    Metabolomics 12/2014; 10(6). DOI:10.1007/s11306-014-0664-8 · 3.97 Impact Factor
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    ABSTRACT: Abutilon theophrasti Medik., previously found to be rather insensitive to benzoxazinoid containing rye mulch and the allelochemical benzoxazolin-2(3H)-one (BOA), can be associated with the zygomycete Actinomucor elegans, whereby the fungus colonizes the root relatively superficially and mainly in the maturation zone. The fungus mitigates necrosis of the cotyledons when seedlings are incubated with 2 mM BOA, in contrast to those that lack the fungus. In liquid cultures of the fungus, tryptophan was identified. The accumulation of tryptophan is increased in presence of BOA. This amino acid seems to be important in protecting Abutilon against BOA and its derivatives since it suppressed the accumulation of BOA derived, highly toxic 2-aminophen-oxazin-3-one (APO) in the medium and on the root surface during BOA incubations of Abutilon seedlings. Although A. elegans is insensitive to BOA and APO, the fungus is not able to protect the plant against harmful effects of APO, when seedlings are treated with the compound. Abutilon can detoxify BOA via BOA-6-OH glucosylation probably by a cell wall associated glucosyltransferase, but only low amounts of the product accumulate. Low tryptophan concentrations can contribute to a degradation of the toxic intermediate BOA-6-OH by Fenton reactions, whereby the amino acid is oxidized. One of the oxidation products was identified as 4(1H)-quinolinone, which is the core substructure of the quorum sensing molecule 2-heptyl-3-hydroxy-4-quinolone. The mutualistic association of Abutilon theophrasti with Actinomucor elegans is considered as opportunistic and facultative. Such plant-fungus associations depend rather likely on environmental conditions, such as the mode of fertilization.
    Journal of Chemical Ecology 11/2014; DOI:10.1007/s10886-014-0529-7 · 2.24 Impact Factor
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    ABSTRACT: Abstract Context: Ferula foetida Regel (Apiaceae) is an Iranian medicinal plant with various biological activities including antispasmodic and anthelmintic. Objective: The sulfur compounds from the roots of F. foetida were isolated and characterized to test their cytotoxic and antimicrobial activities. Materials and methods: The methanolic extract of the roots of F. foetida was fractionated using silica column chromatography. The components of each fraction were further purified using RP-HPLC. Their structures were elucidated by 1- and 2-D NMR spectroscopy as well as HREIMS. Their cytotoxic and antimicrobial activities were evaluated using Alamar Blue assay and broth microdilution method, respectively. Results: Four new thiophene derivatives, namely foetithiophenes C-F (3-6), together with four known compounds, foetithiophenes A (1) and B (2), coniferaldehyde, and sinapic aldehyde, were isolated from the roots of F. foetida. Antimicrobial activities were observed in particular against the Gram-positive bacteria. The best antimicrobial activity was observed for compound 6 against B. cereus with a MIC value 50 µg/mL. The tested compounds did not show cytotoxic properties against MCF-7 and K562 cells. Conclusion: Four new thiophene derivatives including foetithiophenes C-F (3-6) were characterized from the roots of F. foetida. Foetithiophene F (6) exhibited the most potent activity against the Gram-positive bacteria B. cereus.
    Pharmaceutical Biology 11/2014; 53(5):1-5. DOI:10.3109/13880209.2014.939765 · 1.34 Impact Factor
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    ABSTRACT: Here we provide evidence that 3α-acetyloxy-tir-8,24-dien-21-oic acid (αATA(8,24)) inhibits the Akt/mTOR signaling. αATA(8,24) and other tirucallic acids were isolated from the acetylated extract of the oleo gum resin of Boswellia serrata to chemical homogeneity. Compared to related tirucallic acids, αATA(8,24) was the most potent inhibitor of the proliferation of androgen-insensitive prostate cancer cells in vitro and in vivo, in prostate cancer xenografted onto chick chorioallantoic membranes. αATA(8,24) induced loss of cell membrane asymmetry, caspase 3 activation, and DNA fragmentation in vitro and in vivo. These effects were selective for cancer cells, because αATA(8,24) exerted overt toxic effects neither on peripheral blood mononuclear cells nor on the chick embryo. At the molecular level, αATA(8,24) inhibited the Akt1 kinase activity. Prior to all biochemical signs of cellular dysfunction, αATA(8,24) induced, inhibition of the Akt downstream target, mTOR as indicated by dephosphorylation of S6K1. This event was followed by decreased expression of cell cycle regulators, such as cyclin D1, cyclin E, and cyclin B1, as well as cyclin-dependent kinases CDK4 and CDK2, and phospho retinoblastoma protein, which led to inhibition of the cell cycle progression. In agreement with the mTOR inhibition, αATA(8,24) and rapamycin increased the volume of acidic vesicular organelles. In contrast to rapamycin, αATA(8,24) destabilized lysosomal and mitochondrial membranes, and induced ROS production in cancer cells. The ability of αATA(8,24) to inhibit Akt/mTOR signaling and to induce simultaneously oxidative stress could be exploited for the development of novel antitumor therapeutics with a lower profile of toxic side effects.
    Journal of Pharmacology and Experimental Therapeutics 10/2014; DOI:10.1124/jpet.114.217323 · 3.86 Impact Factor
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    ABSTRACT: Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet it is necessary in order to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication [1]. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies, and females mate preferentially with dominant territorial males, which they visit in aggregations or leks [2]. Dominant males have thicker urinary bladder muscular walls than subordinates or females and store large volumes of urine, which they release at increased frequency in the presence of subordinate males or preovulatory, but not postspawned, females [3-5]. Females exposed to dominant-male urine augment their release of the oocyte maturation-inducing steroid 17α,20β-dihydroxypregn-4-en-3-one (17,20β-P) [6]. Here we isolate and identify a male Mozambique tilapia urinary sex pheromone as two epimeric (20α- and 20β-) pregnanetriol 3-glucuronates. We show that both males and females have high olfactory sensitivity to the two steroids, which cross-adapt upon stimulation. Females exposed to both steroids show a rapid, 10-fold increase in production of 17,20β-P. Thus, the identified urinary steroids prime the female endocrine system to accelerate oocyte maturation and possibly promote spawning synchrony. Tilapia are globally important as a food source but are also invasive species, with devastating impact on local freshwater ecosystems [7, 8]. Identifying the chemical cues that mediate reproduction may lead to the development of tools for population control [9-11].
    Current Biology 08/2014; 24(18):2130-2135. DOI:10.1016/j.cub.2014.07.049 · 9.92 Impact Factor
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    ABSTRACT: Abutilon theophrasti is one of the most problematic weeds worldwide. Rye mulches, rich in benzoxazinoids, could not suppress Abutilon (Herbiseeds) due to its avoidance of high BOA/BOA detoxification product accumulation and phytotoxic 2-aminophenoxazinone production. Since Abutilon theophrasti seed coats harbour a variety of fungi and bacteria, a participation of those organisms in BOA degradation was assumed. The avoidance of high detoxification product/BOA accumulation in the roots was correlated with the presence of the Zygomycete Actinomucor elegans, which is known to colonize Abutilon seed coats. The microorganism(s) produced plant growth promoting compounds, whereby tryptophan excretion was stimulated by BOA. In Fenton reactions with BOA, tryptophan accelerates the destruction of the allelochemical via hydroxylated BOA molecules, when used in defined ratios. Destruction of BOA via hydroxylated molecules presents a new pathway for BOA degradation without accumulation of 2-aminophenoxazinone. During this process tryptophan is also degraded. Applications of high concentrations of tryptophan led, however, to a higher, channelled synthesis of BOA-6-O-glucoside in the roots, probably to slow down oxygen consuming Fenton reactions. From all possible hydroxylated BOA molecules, BOA-6-OH is the best substrate for Oglucosylation. Incubations in presence of the mono-oxygenase effector 2-bromo-4´-nitroacetophenone revealed that those enzymes are mainly responsible for BOA-6-OH synthesis and only a minor part results from Fenton reactions. The study elucidates the important role of plant-microorganism associations in the survival of allelopathic attacks.
    7th World Congress on Allelopathy: “Complex Interactions in a Changing Climate”, International Allelopathy Society., Vigo, Spain; 07/2014
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    ABSTRACT: The increasing resistance level of insect pest species is a major concern to agriculture worldwide. The cotton bollworm, Helicoverpa armigera, is one of the most important pest species due to being highly polyphagous, geographically widespread, and resistant towards many chemical classes of insecticides. We previously described the mechanism of fenvalerate resistance in Australian populations conferred by the chimeric cytochrome P450 monooxygenase CYP337B3, which arose by unequal crossing-over between CYP337B1 and CYP337B2. Here, we show that this mechanism is also present in the cypermethrin-resistant FSD strain from Pakistan. The Pakistani and the Australian CYP337B3 alleles differ by 18 synonymous and three nonsynonymous SNPs and additionally in the length and sequence of the intron. Nevertheless, the activity of both CYP337B3 proteins is comparable. We demonstrate that CYP337B3 is capable of metabolizing cypermethrin (trans- and especially cis-isomers) to the main metabolite 4'-hydroxycypermethrin, which exhibits no intrinsic toxicity towards susceptible larvae. In a bioassay, CYP337B3 confers a 7-fold resistance towards cypermethrin in FSD larvae compared to susceptible larvae from the Australian TWB strain lacking CYP337B3. Linkage analysis shows that presence of CYP337B3 accounts for most of the cypermethrin resistance in the FSD strain; up-regulation of other P450s in FSD plays no detectable role in resistance. The presence or absence of CYP337B3 can be easily detected by a simple PCR screen, providing a powerful tool to rapidly distinguish resistant from susceptible individuals in the field and to determine the geographical distribution of this resistance gene. Our results suggest that CYP337B3 evolved twice independently by unequal crossing-over between CYP337B2 and two different CYP337B1 alleles.
    Insect Biochemistry and Molecular Biology 07/2014; 53:54-65. DOI:10.1016/j.ibmb.2014.07.006 · 3.42 Impact Factor
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    ABSTRACT: Nudicaulins are unique alkaloids responsible for the yellow color of the petals of some papaveraceaous plants. To elucidate the unknown biosynthetic origin of the skeleton, a (13) CO2 -pulse/chase experiment was performed with growing Papaver nudicaule plants. (13) C NMR analysis revealed more than 20 multiple (13) C-enriched isotopologues in nudicaulins from the petals of (13) CO2 -labeled plants. The complex labeling pattern was compared with the isotopologue composition of a kaempferol derivative that was isolated from petals of the same (13) CO2 -labeled plants. The deconvolution of the labeling profiles indicated that the nudicaulin scaffold is assembled from products or intermediates of indole metabolism, the phenylpropanoid pathway, and the polyketide biosynthesis. Naringenin-type compounds and tryptophan/tryptamine are potential substrates for the condensation reaction finally generating the aglycone skeleton of nudicaulins.
    ChemBioChem 07/2014; 15(11). DOI:10.1002/cbic.201402109 · 3.06 Impact Factor
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    Jingjing Fang, Bernd Schneider
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    ABSTRACT: Unlike unicellular organisms, plants have evolved as complex organisms that are defined by their ability to distribute special vital functions to spatially separated organs and tissues. Current phytochemical approaches mostly ignore this fact by analysing samples that consist of different cell types and thus average the information obtained. A comprehensive metabolite analysis with high spatial resolution is essential to fully characterise the state of a certain tissue; hence, the analysis of metabolites occurring in specialised plant cells is of considerable interest in chemical ecology, plant natural product chemistry and other bioscience disciplines. Laser microdissection (LMD), including laser capture microdissection and laser microdissection and pressure catapulting, is a convenient sampling technique to harvest homogeneous cell types for the microanalysis of plant metabolites. The objective of this work is to provide an introduction to LMD methodology and a concise review of recent applications of LMD in the high-resolution analysis of metabolites in different plant materials. A step-by-step approach to LMD sampling techniques is described. How LMD can be used to sample cells or microscopic tissue pieces from different plant organs, such as leaves, stems, and seeds, is shown in detail. Finally, the future of LMD in plant metabolites analysis is discussed. This review summarises studies over the past decade not only showing technical details but also indicating the wide application of this method for high-resolution plant metabolite analysis. Laser microdissection is a powerful sampling technique for plant micrometabolic profiling and metabolomics research. Copyright © 2013 John Wiley & Sons, Ltd.
    Phytochemical Analysis 07/2014; 25(4). DOI:10.1002/pca.2477 · 2.45 Impact Factor
  • Yulia Monakhova, Bernd Schneider
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    ABSTRACT: Diarylheptanoids have been reported as biosynthetic precursors of phenylphenalenones in plants. Quantum chemical calculations of molecular geometry and orbitals were used to elaborate which structural features are required to determine if diarylheptanoids can undergo an intramolecular Diel-Alder reaction to form phenylphenalenones. The computational data showed that an ortho-quinone- or a hydoxyketone-bearing ring A, containing the dienophile moiety, and a heptadiene chain with conjugated cisoid double bonds at C-4/C-6 and a saturated segment consisting of two sp3-carbon atoms, are required. Only four diarylheptanoids out of eighteen studied compounds proved to be suitable candidates. Among them are two 3,5-dideoxy compounds and two other compounds oxygenated only at C-3, suggesting that lachnanthocarpone, a representative of the 6-oxygenated phenylphenalenones, and anigorufone, a representative of the 6-deoxy phenylphenalenones, are not connected via a precursor-product relationship ("late reduction at C-6") but formed through partially separate pathways.
    Molecules 04/2014; 19(4):5231-42. DOI:10.3390/molecules19045231 · 2.10 Impact Factor
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    ABSTRACT: The global yield of bananas-one of the most important food crops-is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant-nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques (1)H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R. similis-caused lesions of the plants. The striking antinematode activity of the phenylphenalenone anigorufone, its ingestion by the nematode, and its subsequent localization in lipid droplets within the nematode is reported. The importance of varying local concentrations of these specialized metabolites in infected plant tissues, their involvement in the plant's defense system, and derived strategies for improving banana resistance are highlighted.
    Proceedings of the National Academy of Sciences 12/2013; 111(1). DOI:10.1073/pnas.1314168110 · 9.81 Impact Factor
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    ABSTRACT: The cytochrome P450 family encompasses the largest family of enzymes in plant metabolism, and the functions of many of its members in Arabidopsis thaliana are still unknown. Gene coexpression analysis pointed to two P450s that were coexpressed with two monoterpene synthases in flowers and were thus predicted to be involved in monoterpenoid metabolism. We show that all four selected genes, the two terpene synthases (TPS10 and TPS14) and the two cytochrome P450s (CYP71B31 and CYP76C3), are simultaneously expressed at anthesis, mainly in upper anther filaments and in petals. Upon transient expression in Nicotiana benthamiana, the TPS enzymes colocalize in vesicular structures associated with the plastid surface, whereas the P450 proteins were detected in the endoplasmic reticulum. Whether they were expressed in Saccharomyces cerevisiae or in N. benthamiana, the TPS enzymes formed two different enantiomers of linalool: (-)-(R)-linalool for TPS10 and (+)-(S)-linalool for TPS14. Both P450 enzymes metabolize the two linalool enantiomers to form different but overlapping sets of hydroxylated or epoxidized products. These oxygenated products are not emitted into the floral headspace, but accumulate in floral tissues as further converted or conjugated metabolites. This work reveals complex linalool metabolism in Arabidopsis flowers, the ecological role of which remains to be determined.
    The Plant Cell 11/2013; 25(11). DOI:10.1105/tpc.113.117382 · 9.58 Impact Factor
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    ABSTRACT: Aldoximes are known as floral and vegetative plant volatiles but also as biosynthetic intermediates for other plant defense compounds. While the cytochrome P450 monooxygenases (CYP) from the CYP79 family forming aldoximes as biosynthetic intermediates have been intensively studied, little is known about the enzymology of volatile aldoxime formation. We characterized two P450 enzymes, CYP79D6v3 and CYP79D7v2, which are involved in herbivore-induced aldoxime formation in western balsam poplar (Populus trichocarpa). Heterologous expression in Saccharomyces cerevisiae revealed that both enzymes produce a mixture of different aldoximes. Knockdown lines of CYP79D6/7 in gray poplar (Populus × canescens) exhibited a decreased emission of aldoximes, nitriles, and alcohols, emphasizing that the CYP79s catalyze the first step in the formation of a complex volatile blend. Aldoxime emission was found to be restricted to herbivore-damaged leaves and is closely correlated with CYP79D6 and CYP79D7 gene expression. The semi-volatile phenylacetaldoxime decreased survival and weight gain of gypsy moth (Lymantria dispar) caterpillars, suggesting that aldoximes may be involved in direct defense. The wide distribution of volatile aldoximes throughout the plant kingdom and the presence of CYP79 genes in all sequenced genomes of angiosperms suggest that volatile formation mediated by CYP79s is a general phenomenon in the plant kingdom.
    The Plant Cell 11/2013; 25(11). DOI:10.1105/tpc.113.118265 · 9.58 Impact Factor

Publication Stats

3k Citations
646.44 Total Impact Points

Institutions

  • 1998–2015
    • Max Planck Institute for Chemical Ecology
      • Department of Molecular Ecology
      Jena, Thuringia, Germany
  • 2007–2014
    • Max Planck Institute for Biogeochemistry Jena
      Jena, Thuringia, Germany
    • National University of Colombia
      Μπογκοτά, Bogota D.C., Colombia
  • 2008–2010
    • Mashhad University of Medical Sciences
      • Department of Pharmacognosy
      Mashad, Razavi Khorasan, Iran
  • 2006
    • Leibniz Institute for Age Research - Fritz Lipmann Institute
      Jena, Thuringia, Germany
    • Universität Ulm
      • Institute of Natural Medicine and Clinical Pharmacology
      Ulm, Baden-Wuerttemberg, Germany
  • 2004–2006
    • Friedrich-Schiller-University Jena
      • Institut für Pharmazie
      Jena, Thuringia, Germany
  • 2005
    • Max Planck Institute for Plant Breeding Research
      • Department of Plant Microbe Interactions
      Köln, North Rhine-Westphalia, Germany
  • 2002
    • National Academy of Sciences of Belarus
      • Institute of Bioorganic Chemistry
      Myenyesk, Minsk, Belarus
  • 1996–1998
    • Leibniz Institute for Plant Biochemistry
      Halle-on-the-Saale, Saxony-Anhalt, Germany