Roepke J.,Brock University |
Salim V.,Brock University |
Wu M.,Brock University |
Thamm A.M.K.,Brock University |
And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010
The monoterpenoid indole alkaloids (MIAs) of Madagascar periwinkle (Catharanthus roseus) continue to be the most important source of natural drugs in chemotherapy treatments for a range of human cancers. These anticancer drugs are derived from the coupling of catharanthine and vindoline to yield powerful dimeric MIAs that prevent cell division. However the precise mechanisms for their assembly within plants remain obscure. Here we report that the complex development-, environment-, organ-, and cell-specific controls involved in expression of MIA pathways are coupled to secretory mechanisms that keep catharanthine and vindoline separated from each other in living plants. Although the entire production of catharanthine and vindoline occurs in young developing leaves, catharanthine accumulates in leaf wax exudates of leaves, whereas vindoline is found within leaf cells. The spatial separation of these two MIAs provides a biological explanation for the low levels of dimeric anticancer drugs found in the plant that result in their high cost of commercial production. The ability of catharanthine to inhibit the growth of fungal zoospores at physiological concentrations found on the leaf surface of Catharanthus leaves, as well as its insect toxicity, provide an additional biological role for its secretion. We anticipate that this discovery will trigger a broad search for plants that secrete alkaloids, the biological mechanisms involved in their secretion to the plant surface, and the ecological roles played by them.
Ma H.,Alfred Wegener Institute for Polar and Marine Research |
Krock B.,Alfred Wegener Institute for Polar and Marine Research |
Tillmann U.,Alfred Wegener Institute for Polar and Marine Research |
Muck A.,Max Planck Institute For Chemische Okologie |
And 3 more authors.
Harmful Algae | Year: 2011
Certain strains of the toxigenic dinoflagellate Alexandrium tamarense produce potent allelochemicals with lytic activity against a wide variety of marine microorganisms. Our efforts to characterize these allelochemicals from a lytic strain focused on the less polar components because of their higher lytic activity. Fractionation and partial purification after solid phase extraction (SPE) were achieved via alternative chromatographic methods, namely HPLC separation on C8 and HILIC phases. Through MALDI-TOF mass spectrometry we compared the mass differences in SPE, C8 HPLC, and HILIC fractions between a lytic and non-lytic strain of A. tamarense. Several large species with masses between 7 kDa and 15 kDa were found in the HILIC lytic fraction by MALDI-TOF MS. Tryptic digestion and tryptic digestion-coupled size-exclusion chromatography (SEC) suggested that the lytic compounds are large non-proteinaceous molecules (<23.3 kDa, trypsin). Although there is no direct proof that the large molecules found in the lytic HILIC fraction are responsible for the lytic activity of this fraction, the mass range deduced from SEC strongly supports this hypothesis. Total sugar content analysis showed that the lytic HILIC fraction contained two-fold more sugar than the non-lytic one. Nevertheless, the low percentage of saccharide per dry mass equivalent (0.18 ± 0.01%) indicates that sugar residues are likely not a major component of the lytic compounds. We concluded that at least one group of lytic allelochemicals produced by A. tamarense comprise a suite of large non-proteinaceous and probably non-polysaccharide compounds between 7 kDa and 15 kDa. © 2011 Elsevier B.V.
Fneich S.,University of Perpignan |
Fneich S.,CNRS Host-Pathogen-Environment Interactions Laboratory |
Dheilly N.,University of Perpignan |
Dheilly N.,CNRS Host-Pathogen-Environment Interactions Laboratory |
And 9 more authors.
Parasites and Vectors | Year: 2013
Background: Biomphalaria glabrata is the mollusc intermediate host for Schistosoma mansoni, a digenean flatworm parasite that causes human intestinal schistosomiasis. An estimated 200 million people in 74 countries suffer from schistosomiasis, in terms of morbidity this is the most severe tropical disease after malaria. Epigenetic information informs on the status of gene activity that is heritable, for which changes are reversible and that is not based on the DNA sequence. Epigenetic mechanisms generate variability that provides a source for potentially heritable phenotypic variation and therefore could be involved in the adaptation to environmental constraint. Phenotypic variations are particularly important in host-parasite interactions in which both selective pressure and rate of evolution are high. In this context, epigenetic changes are expected to be major drivers of phenotypic plasticity and co-adaptation between host and parasite. Consequently, with characterization of the genomes of invertebrates that are parasite vectors or intermediate hosts, it is also essential to understand how the epigenetic machinery functions to better decipher the interplay between host and parasite. Methods. The CpGo/e ratios were used as a proxy to investigate the occurrence of CpG methylation in B. glabrata coding regions. The presence of DNA methylation in B. glabrata was also confirmed by several experimental approaches: restriction enzymatic digestion with isoschizomers, bisulfite conversion based techniques and LC-MS/MS analysis. Results: In this work, we report that DNA methylation, which is one of the carriers of epigenetic information, occurs in B. glabrata; approximately 2% of cytosine nucleotides are methylated. We describe the methylation machinery of B. glabrata. Methylation occurs predominantly at CpG sites, present at high ratios in coding regions of genes associated with housekeeping functions. We also demonstrate by bisulfite treatment that methylation occurs in multiple copies of Nimbus, a transposable element. Conclusions: This study details DNA methylation for the first time, one of the carriers of epigenetic information in B. glabrata. The general characteristics of DNA methylation that we observed in the B. glabrata genome conform to what epigenetic studies have reported from other invertebrate species. © 2013 Fneich et al.; licensee BioMed Central Ltd.
Duque L.,University of Antioquia |
Zapata C.,University of Antioquia |
Rojano B.,National University of Colombia |
Schneider B.,Max Planck Institute For Chemische Okologie |
Otalvaro F.,University of Antioquia
Organic Letters | Year: 2013
2,4-Dihydroxy-9-phenyl-1H-phenalen-1-one (4-hydroxyanigorufone, 1), a compound isolated from Anigozanthos flavidus and Monochoria elata, displayed a high radical scavenging capacity in the ORAC assay. A systematic approach was adopted in order to explore the effect of each functional group. H-Atom transfer from the phenolic hydroxyl, a captodative effect from the hydroxy ketone, and the presumed involvement of the phenyl ring in the termination step of the radical reaction were disclosed as relevant features of this type of antioxidant. © 2013 American Chemical Society.
Duque L.,University of Antioquia |
Restrepo C.,University of Antioquia |
Saez J.,University of Antioquia |
Gil J.,National University of Colombia |
And 2 more authors.
Tetrahedron Letters | Year: 2010
5-Methoxy-3H-naphtho[2,1,8-mna]xanthen-3-one (musafluorone, 1), the only naphthoxanthenone reported so far from Musaceae, was synthesized starting from 2-naphthol in nine steps and resulted in an overall yield of 3%. Grignard addition of phenylmagnesium bromide to 4-methoxyperinaphthenone afforded the corresponding 4-methoxy-9-phenylphenalenone which, after epoxidation and methyl transposition, was subjected to a photochemical cyclization procedure to furnish 1. © 2010 Elsevier Ltd. All rights reserved.
Bussell J.D.,University of Western Australia |
Reichelt M.,Max Planck Institute For Chemische Okologie |
Wiszniewski A.A.G.,University of Western Australia |
Gershenzon J.,Max Planck Institute For Chemische Okologie |
And 2 more authors.
Plant Physiology | Year: 2014
Secondary metabolites derived from benzoic acid (BA) are of central importance in the interactions of plants with pests, pathogens, and symbionts and are potentially important in plant development. Peroxisomal b-oxidation has recently been shown to contribute to BA biosynthesis in plants, but not all of the enzymes involved have been defined. In this report, we demonstrate that the peroxisomal ATP-binding cassette transporter COMATOSE is required for the accumulation of benzoylated secondary metabolites in Arabidopsis (Arabidopsis thaliana) seeds, including benzoylated glucosinolates and substituted hydroxybenzoylcholines. The ABNORMAL INFLORESCENCE MERISTEM protein, one of two multifunctional proteins encoded by Arabidopsis, is essential for the accumulation of these compounds, and MULTIFUNCTIONAL PROTEIN2 contributes to the synthesis of substituted hydroxybenzoylcholines. Of the two major 3-ketoacyl coenzyme A thiolases, KAT2 plays the primary role in BA synthesis. Thus, BA biosynthesis in Arabidopsis employs the same core set of b-oxidation enzymes as in the synthesis of indole-3-acetic acid from indole-3-butyric acid. © 2014 American Society of Plant Biologists. All Rights Reserved.
Hidalgo W.,Max Planck Institute For Chemische Okologie |
Chandran J.N.,Max Planck Institute For Chemische Okologie |
Menezes R.C.,Max Planck Institute For Chemische Okologie |
Otalvaro F.,University of Antioquia |
Schneider B.,Max Planck Institute For Chemische Okologie
Plant, Cell and Environment | Year: 2016
Phenylphenalenones, polycyclic aromatic natural products from some monocotyledonous plants, are known as phytoalexins in banana (Musa spp.). In this study, 1H nuclear magnetic resonance (NMR)-based metabolomics along with liquid chromatography andmass spectrometry were used to explore the chemical responses of the susceptible 'Williams' and the resistant 'Khai Thong Ruang' Musa varieties to the ascomycete fungusMycosphaerella fijiensis, the agent of the black leaf Sigatoka disease. Principal component analysis discriminated strongly between infected and non-infected plant tissue, mainly because of 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 defence of Musa plants. © 2016 John Wiley & Sons Ltd.
Kaltenpoth M.,Max Planck Institute For Chemische Okologie
BioSpektrum | Year: 2014
Microbial symbionts play an essential role for the ecology and evolution of most multicellular organisms. Firebugs (Hemiptera, Pyrrhocoridae) are associated with actinobacterial symbionts in the mid-gut that supplement limiting B-vitamins and are tightly integrated into the host's metabolism. The symbiosis is widespread among firebugs and enables them to subsist on Malvales seeds as the sole nutritional resource. © 2014 Springer-Verlag Berlin Heidelberg.
Mithofer A.,Max Planck Institute For Chemische Okologie |
Schuman M.C.,Max Planck Institute For Chemische Okologie
Biologie in Unserer Zeit | Year: 2014
Plants are master chemists who synthesize an arsenal of compounds which efficiently defend against herbivore attack. In addition to chemicals which directly affect herbivores, attacked plants release characteristic bouquets of low molecular weight volatile compounds, mostly terpenes and fatty acid derivatives, into their environment. These volatiles serve as signals which can attract predators and parasitoids to attack herbivores, thus indirectly defending the plant. Volatiles may also be perceived by remote parts of the same plant, which can then prepare to defend themselves against imminent attack, and thus react more quickly when attacked. These natural phenomena suggest alternative strategies for agricultural pest management. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Zhang J.,Max Planck Institute of Molecular Plant Physiology |
Khan S.A.,Max Planck Institute For Chemische Okologie |
Hasse C.,Max Planck Institute of Molecular Plant Physiology |
Ruf S.,Max Planck Institute of Molecular Plant Physiology |
And 2 more authors.
Science | Year: 2015
Double-stranded RNAs (dsRNAs) targeted against essential genes can trigger a lethal RNA interference (RNAi) response in insect pests. The application of this concept in plant protection is hampered by the presence of an endogenous plant RNAi pathway that processes dsRNAs into short interfering RNAs.We found that long dsRNAs can be stably produced in chloroplasts, a cellular compartment that appears to lack an RNAi machinery. When expressed from the chloroplast genome, dsRNAs accumulated to as much as 0.4% of the total cellular RNA.Transplastomic potato plants producing dsRNAs targeted against the b-actin gene of the Colorado potato beetle, a notorious agricultural pest, were protected from herbivory and were lethal to its larvae. Thus, chloroplast expression of long dsRNAs can provide crop protection without chemical pesticides. © 2015, American Association for the Advancement of Science. All rights reserved.