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Jacques M Pasteels - One of the best experts on this subject based on the ideXlab platform.
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uptake and metabolism of 14c rinderine and 14c retronecine in leaf beetles of the genus platyphora and alkaloid accumulation in the exocrine Defensive Secretions
Chemoecology, 2003Co-Authors: Jacques M Pasteels, Claudine Theuring, Donald M WindsorAbstract:Sequestration and processing of pyrrolizidine alkaloids (PAs) by leaf beetles of the genus Platyphora were investigated. Tracer experiments with labeled alkaloids were performed with P. eucosma feeding on Koanophyllon panamense (Asteraceae, tribe Eupatorieae). P. eucosma catalyzes the same reactions previously demonstrated for P. boucardi specialized to Prestonia portobellensis (Apocynaceae): (i) epimerization of rinderine to intermedine; (ii) esterification of retronecine yielding insect-specific PAs; (iii) efficient transport of the PAs as free bases into the Defensive Secretions. P. bella feeding on Tournefortia cuspidata (Boraginaceae) shows the same sequestration behavior and ability to synthesize the specific retronecine esters. P. ligata, a species phylogenetically closely related to the PA adapted species and clustering in the same clade, but feeding on a host plant devoid of PAs, feeds easily on PA treated host-plant leaves, but does not sequester or metabolize PAs. P. kollari a species clustering outside the PA clade refused to feed on its food-plant leaves painted with PAs. The results are discussed in relation to host-plant selection of the PA adapted species and the role of PAs in chemical defense.
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Sequestration and Metabolism of Protoxic Pyrrolizidine Alkaloids by Larvae of the Leaf Beetle Platyphora boucardi and Their Transfer via Pupae into Defensive Secretions of Adults
Journal of Chemical Ecology, 2003Co-Authors: Jacques M Pasteels, Claudine Theuring, Ludger WitteAbstract:Several neotropical leaf-beetles of the genus Platyphora ingest and specifically metabolize plant acquired pyrrolizidine alkaloids (PAs) of the lycopsamine type (e.g., rinderine or intermedine) and enrich the processed alkaloids in their exocrine Defensive Secretions. In contrast to the related palaearctic leaf beetles of the genus Oreina , which absorb and store only the non-toxic alkaloid N -oxides, Platyphora sequesters PAs exclusively as protoxic tertiary amines. In this study, the ability of P. boucardi larvae to accumulate PAs was investigated. Tracer studies with [^14C]rinderine and its N -oxide revealed that P. boucardi larvae, like adult beetles, utilize the two alkaloidal forms with the same efficiency, but accumulate the alkaloid as a tertiary amine exclusively. Ingested rinderine is rapidly epimerized to intermedine, which is localized in the hemolymph and all other tissues; it is also detected on the larval surface. Like adults, larvae are able to synthesize their own alkaloid esters (beetle PAs) from orally administered [^14C]retronecine and endogenous aliphatic 2-hydroxy acids. These retronecine esters show the same tissue distribution as intermedine. A long-term feeding experiment lasting for almost four months revealed that retronecine esters synthesized from [^14C]retronecine in the larvae are transferred from larvae via pupae into the exocrine glands of adult beetles. Pupae contain ca. 45% of the labeled retronecine originally ingested, metabolized, and stored by larvae; ca. 12% of larval radioactivity could be recovered from the Defensive Secretions of adults sampled successively over two and a half months. Almost all of this radioactivity is found in the insect-made retronecine esters that are highly enriched in the Defensive Secretions, i.e., more than 200-fold higher concentration compared to pupae.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native Mr of 334 000 and a subunit Mr of 79 000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion. © 2002 Elsevier Science Ltd. All rights reserved.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native M(r) of 334,000 and a subunit M(r) of 79,000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion.
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pyrrolizidine alkaloids and pentacyclic triterpene saponins in the Defensive Secretions of platyphora leaf beetles
Chemoecology, 2001Co-Authors: Jacques M Pasteels, Arnaud Termonia, Donald M Windsor, Ludger Witte, Claudine TheuringAbstract:Field collected exocrine Defensive Secretions of nine neotropical Platyphora species were analyzed for the presence of plant acquired pyrrolizidine alkaloids (PAs) and pentacyclic triterpene saponins. All species secrete saponins. In addition, five species feeding on Tournefortia (Boraginaceae), Koanophyllon (Asteraceae, tribe Eupatorieae) and Prestonia (Apocynaceae) were shown to sequester PAs of the lycopsamine type, which are characteristic for species of the three plant families. The PA sequestering species commonly store intermedine, lycopsamine and their O3′-acetyl or propionyl esters as well as O7- and O9-hydroxyisovaleryl esters of retronecine. The latter as well as the O3′-acyl esters were not found in the beetles’ host plants, suggesting the ability of the beetles to esterify plant derived retronecine and intermedine or its stereoisomers. Despite the conformity of the beetles’ PA patterns, considerable inconsistencies exist regarding the PA patterns of the respective host plants. One host plant was devoid of PAs, while another contained only simple necines. Since the previous history of the field collected beetles was unknown this discrepancy remains obscure. In contrast to the Palearctic chrysomeline leaf beetles, e.g. some Oreina species which ingest and store PAs as their non-toxic N-oxides, Platyphora leaf beetles absorb and store PAs as the toxic free base (tertiary PA), but apparently avoid to accumulate PAs in the haemolymph. This suggests that Chrysolina and Platyphora leaf beetles developed different lines of adaptations in their parallel evolution of PA mediated chemical defense.
Thomas Hartmann - One of the best experts on this subject based on the ideXlab platform.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native M(r) of 334,000 and a subunit M(r) of 79,000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native Mr of 334 000 and a subunit Mr of 79 000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion. © 2002 Elsevier Science Ltd. All rights reserved.
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Sequestration of ingested [14C]senecionine N-oxide in the exocrine Defensive Secretions of chrysomelid beetles
Journal of chemical ecology, 1991Co-Authors: Adelheid Ehmke, Jacques M Pasteels, Martine Rowell-rahier, Thomas HartmannAbstract:Oreina cacaliae (Chrysomelidae) sequesters in its elytral and pronotal Defensive secretion theN-oxides of pyrrolizidine alkaloids (PAN-oxides) from its food plantAdenostyles alliariae (Asteraceae). [14C]SenecionineN-oxide was applied for detailed studies of PAN-oxide sequestration. An average of 11.4% of total radioactivity is taken up by individual beetles which had received [14C]senecionineN-oxide with their food leaves 8 days before. An average of 28.9% of the ingested radioactivity could be recovered from the Defensive Secretions collected twice, i.e., 5 and 8 days after tracer feeding. The tracer transfer into the secretion seems to be a slow but progressive process as indicated by the high percentage of tracer still recovered from the secretion sampled after 8 days. Chromatographic analysis revealed that [14C]senecionineN-oxide is the only labeled compound in the Defensive secretion. Beetles that fed on tertiary [14C]senecionine sequestered only trace amounts of radioactivity (exclusively present as labeled IV-oxide) in their Secretions.O. speciosissima, a species also adapted to PA containing food plants, was shown to sequester [14C]senecionineN-oxide with the same efficiency asO. cacaliae. O. bifrons, a specialist feeding onChaerophyllum hirsutum (Apiaceae), rejected PA treated leaf samples already at very low PA concentrations (10 nmol/leaf piece). In bothO. cacaliae andO. speciosissima, [14C]senecionineN-oxide applied by injection into the hemolymph is rapidly transferred into the glands.O. bifrons, not adapted to pyrrolizidine alkaloid containing plants was unable to sequester [14C]-senecionineN- oxide in the secretion but rapidly eliminated the tracer with the frass. Again, only traces of labeled [14C]senecionineN-oxide were found in the Defensive Secretions of the two PA adapted species if labeled senecionine was injected. It is suggested that the beetles are adapted to theN-oxide form of PAs, similarly as their food plants, and that they lack the ability to efficientlyN-oxidize tertiary PAs. No indication forde novo PA synthesis by the beetles was found in tracer feeding experiments with the biogenetic PA precursor putrescine.
Slobodan E. Makarov - One of the best experts on this subject based on the ideXlab platform.
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multifaceted activity of millipede Secretions antioxidant antineurodegenerative and anti fusarium effects of the Defensive Secretions of pachyiulus hungaricus karsch 1881 and megaphyllum unilineatum c l koch 1838 diplopoda julida
PLOS ONE, 2019Co-Authors: B S Ilic, Slobodan E. Makarov, Nikola Unkovic, Aleksandar Kneževic, željko Savkovic, Milica Ljaljevic Grbic, Jelena Vukojevic, Zvezdana Jovanovic, Luka R LucicAbstract:: Members of the millipede order Julida rely on dominantly quinonic Defensive Secretions with several minor, non-quinonic components. The free radical-scavenging activities of ethanol, methanol, hexane, and dichloromethane extracts of Defensive Secretions emitted by Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) were investigated using the ABTS, DPPH, and total reducing power (TRP) tests. The obtained extracts were also tested for inhibition of acetylcholinesterase and tyrosinase activity. Finally, the antifungal potential of both julid extracts was evaluated against seven Fusarium species. Secretions of both species showed activity against free radicals, acetylcholinesterase, tyrosinase, and all of the selected fungal species. The Secretions of P. hungaricus exhibited a more potent antioxidative effect than did those of M. unilineatum, while there were no significant differences of antiacetylcholinesterase activity between the tested extracts. Only the hexane extract of M. unilineatum showed an effect on tyrosinase activity stronger than that of P. hungaricus. Fusarium sporotrichioides, F. graminearum, and F. verticillioides were the fungi most resistant to Secretions of both julids. The Fusarium species most susceptible to the secretion of P. hungaricus was F. avenaceum, while the concentrations of M. unilienatum extracts needed to inhibit and completely suppress fungal growth were lowest in the case of their action on F. lateritium. Our data support previous findings that julid Defensive Secretions possess an antimicrobial potential and reveal their antioxidative and antineurodegenrative properties. Bearing in mind the chemical complexity of the tested Defensive Secretions, we presume that they can also exhibit other biological activities.
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Chemical Ecology of Cave-Dwelling Millipedes: Defensive Secretions of the Typhloiulini (Diplopoda, Julida, Julidae)
Journal of Chemical Ecology, 2017Co-Authors: Slobodan E. Makarov, Michaela Bodner, Boyan Vagalinski, Dragan Ž. Antić, Ljubodrag V. Vujisić, Doris Reineke, Marina M. Todosijević, Luka R. Lučić, Bojan M. Mitić, Plamen MitovAbstract:Cave animals live under highly constant ecological conditions and in permanent darkness, and many evolutionary adaptations of cave-dwellers have been triggered by their specific environment. A similar “cave effect” leading to pronounced chemical interactions under such conditions may be assumed, but the chemoecology of troglobionts is mostly unknown. We investigated the Defensive chemistry of a largely cave-dwelling julid group, the controversial tribe “Typhloiulini”, and we included some cave-dwelling and some endogean representatives. While chemical defense in juliform diplopods is known to be highly uniform, and mainly based on methyl- and methoxy-substituted benzoquinones, the Defensive Secretions of typhloiulines contained ethyl-benzoquinones and related compounds. Interestingly, ethyl-benzoquinones were found in some, but not all cave-dwelling typhloiulines, and some non-cave dwellers also contained these compounds. On the other hand, ethyl-benzoquinones were not detected in troglobiont nor in endogean typhloiuline outgroups. In order to explain the taxonomic pattern of ethyl-benzoquinone occurrence, and to unravel whether a cave-effect triggered ethyl-benzoquinone evolution, we classed the “Typhloiulini” investigated here within a phylogenetic framework of julid taxa, and traced the evolutionary history of ethyl-benzoquinones in typhloiulines in relation to cave-dwelling. The results indicated a cave-independent evolution of ethyl-substituted benzoquinones, indicating the absence of a “cave effect” on the Secretions of troglobiont Typhloiulini. Ethyl-benzoquinones probably evolved early in an epi- or endogean ancestor of a clade including several, but not all Typhloiulus (basically comprising a taxonomic entity known as “ Typhloiulus sensu stricto”) and Serboiulus . Ethyl-benzoquinones are proposed as novel and valuable chemical characters for julid systematics.
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Defensive Secretions in three ground beetle species insecta coleoptera carabidae
Annales Zoologici Fennici, 2014Co-Authors: Sonja Lecic, Ljubodrag Vujisic, Vele Tesevic, Božidar P M Curcic, Srecko Curcic, Nina B Curcic, Z Nikolic, Boban Anđelkovic, Slobodan Milosavljevic, Slobodan E. MakarovAbstract:The adults of three ground-beetle species were induced to discharge Defensive Secretions into vials. The Secretions were obtained by CH2Cl2 extraction. Altogether 11 compounds were identified by GC-MS analysis. Calosoma sycophanta possesses 10 Defensive compounds, Carabus ullrichii seven, while Abax parallelepipedus has six compounds. Methacrylic, tiglic and isobutyric acids were present in all samples. The first two organic compounds were predominant in the extracts of Abax parallelepipedus. Methacrylic acid and salicylaldehyde were the major compounds in extracts of Calosoma sycophanta. Methacrylic and angelic acids were the major components in extracts of Carabus ullrichii. Propanoic acid was detected for the first time in the family Carabidae and in all animals. 2-Methyl butyric, angelic and benzoic acids were found for the first time in the subfamily Carabinae. Our finding of butyric acid is its first precise identification in the Carabinae subfamily. 2-Methyl butyric, angelic, crotonic, senecioic an...
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chemical defense in millipedes myriapoda diplopoda do representatives of the family blaniulidae belong to the quinone clade
Chemistry & Biodiversity, 2014Co-Authors: Ljubodrag Vujisic, Dragan ž Antic, Ivan Vuckovic, Tatjana Lj Sekulic, V T Tomic, Boris Mandic, Vele Tesevic, Božidar P M Curcic, V Vajs, Slobodan E. MakarovAbstract:The Defensive Secretions of two blaniulid millipedes, Nopoiulus kochii and Cibiniulus phlepsii, were characterized by GC-FID and GC/MS analyses, which showed the presence of a complex mixture of benzoquinones, hydroquinones, and oleates. Altogether, 13 compounds were identified. The major compound in the Secretions of both analyzed species was 2-methyl-1,4-benzoquinone (toluquinone). The second major constituent in the N. kochii secretion was 2-methyl-3,4-(methylenedioxy)phenol, while in that of C. phlepsii, it was 2-methoxy-3-methyl-1,4-benzoquinone. The Defensive secretion of N. kochii also showed a high content of hydroquinones (13.5%) in comparison to that of C. phlepsii (0.8%). Hexyl oleate and octyl oleate were detected for the first time in Defensive millipede fluids. The chemical composition of the Defensive Secretions supports the chemotaxonomic position of the family Blaniulidae in the ‘quinone’ millipede clade.
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Defensive Secretions in Callipodella fasciata (Latzel, 1882; Diplopoda, Callipodida, Schizopetalidae).
Chemistry & biodiversity, 2011Co-Authors: Slobodan E. Makarov, Ljubodrag V. Vujisić, Ivan Vuckovic, Božidar P. M. Ćurčić, Milka Jadranin, Vele Tešević, Tatjana Lj. Sekulić, Srećko Ćurčić, Bojan M. MitićAbstract:The small millipede Callipodella fasciata secretes an earthy smell when disturbed. This secretion was obtained by CH2Cl2 extraction from specimens of both sexes and was identified by GC/MS analyses to be composed of p-cresol (96.5%), phenol (3.5%), and p-ethylphenol (traces). This is the first identification of these compounds in an epigean European callipodidan species and the first report of intergeneric differences in the chemical composition of Defensive Secretions in callipodidans. These compounds have repellent, antimicrobial, and antifungal properties.
Arnaud Termonia - One of the best experts on this subject based on the ideXlab platform.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native Mr of 334 000 and a subunit Mr of 79 000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion. © 2002 Elsevier Science Ltd. All rights reserved.
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characterization of an extracellular salicyl alcohol oxidase from larval Defensive Secretions of chrysomela populi and phratora vitellinae chrysomelina
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Markus Bruckmann, Jacques M Pasteels, Arnaud Termonia, Thomas HartmannAbstract:Larvae of a number of chrysomelid leaf beetles sequester phenol glucosides such as salicin from their food plants, i.e. Salix and Populus spp. Salicin is hydrolyzed in the glandular reservoir of the Defensive glands. The resulting salicyl alcohol (saligenin) is oxidized by an extracellular oxidase. The product salicylaldehyde accumulates as major Defensive compound. The Secretions from Chrysomela populi and Phratora vitellinae were preserved in saturated ammonium sulfate solution and subjected to micro-purification of the oxidase by means of electrophoretic methods. The enzyme from P. vitellinae has a native M(r) of 334,000 and a subunit M(r) of 79,000 indicating a tetrameric enzyme. The isoelectric points of the enzymes from C. populi and P. vitellinae are at pH 5.4 and 5.2, respectively. In the oxidation of salicyl alcohol oxygen functions as electron acceptor yielding hydrogen peroxide as product. Hydrogen peroxide does not accumulate in native Secretions but appears to be degraded most likely by a catalase. The oxidases from the two species show broad pH optima in the range 5.5 to 6.5, they oxidize salicyl alcohol as main substrate. Minor substrates are several ortho-substituted and to a lesser extent meta- but not para-substituted benzyl alcohols. In the presence of 8-hydroxygeraniol only trace amounts of the respective aldehyde are formed. The Km values of salicyl alcohol are 132 mM (C. populi) and 63 mM (P. vitellinae). The extracellular enzyme, which is functionally related to fungal aryl alcohol oxidase (EC 1.1.3.7) and vanillyl alcohol oxidase (EC 1.1.3.38) was named salicyl alcohol oxidase. The continuous formation of salicylaldehyde in the glandular reservoir can be compared to the operation of an enzyme reactor. Due to its low aqueous solubility the produced aldehyde steadily leaves the aqueous reaction fluid and builds up an organic phase which may account for 15% of the total liquid volume of the secretion.
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pyrrolizidine alkaloids and pentacyclic triterpene saponins in the Defensive Secretions of platyphora leaf beetles
Chemoecology, 2001Co-Authors: Jacques M Pasteels, Arnaud Termonia, Donald M Windsor, Ludger Witte, Claudine TheuringAbstract:Field collected exocrine Defensive Secretions of nine neotropical Platyphora species were analyzed for the presence of plant acquired pyrrolizidine alkaloids (PAs) and pentacyclic triterpene saponins. All species secrete saponins. In addition, five species feeding on Tournefortia (Boraginaceae), Koanophyllon (Asteraceae, tribe Eupatorieae) and Prestonia (Apocynaceae) were shown to sequester PAs of the lycopsamine type, which are characteristic for species of the three plant families. The PA sequestering species commonly store intermedine, lycopsamine and their O3′-acetyl or propionyl esters as well as O7- and O9-hydroxyisovaleryl esters of retronecine. The latter as well as the O3′-acyl esters were not found in the beetles’ host plants, suggesting the ability of the beetles to esterify plant derived retronecine and intermedine or its stereoisomers. Despite the conformity of the beetles’ PA patterns, considerable inconsistencies exist regarding the PA patterns of the respective host plants. One host plant was devoid of PAs, while another contained only simple necines. Since the previous history of the field collected beetles was unknown this discrepancy remains obscure. In contrast to the Palearctic chrysomeline leaf beetles, e.g. some Oreina species which ingest and store PAs as their non-toxic N-oxides, Platyphora leaf beetles absorb and store PAs as the toxic free base (tertiary PA), but apparently avoid to accumulate PAs in the haemolymph. This suggests that Chrysolina and Platyphora leaf beetles developed different lines of adaptations in their parallel evolution of PA mediated chemical defense.
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feeding specialization and host derived chemical defense in chrysomeline leaf beetles did not lead to an evolutionary dead end
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Arnaud Termonia, Jacques M Pasteels, Ting H Hsiao, Michel C MilinkovitchAbstract:Combination of molecular phylogenetic analyses of Chrysomelina beetles and chemical data of their Defensive Secretions indicate that two lineages independently developed, from an ancestral autogenous metabolism, an energetically efficient strategy that made the insect tightly dependent on the chemistry of the host plant. However, a lineage (the interrupta group) escaped this subordination through the development of a yet more derived mixed metabolism potentially compatible with a large number of new host-plant associations. Hence, these analyses on leaf beetles document a mechanism that can explain why high levels of specialization do not necessarily lead to "evolutionary dead ends."
Luka R Lucic - One of the best experts on this subject based on the ideXlab platform.
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multifaceted activity of millipede Secretions antioxidant antineurodegenerative and anti fusarium effects of the Defensive Secretions of pachyiulus hungaricus karsch 1881 and megaphyllum unilineatum c l koch 1838 diplopoda julida
PLOS ONE, 2019Co-Authors: B S Ilic, Slobodan E. Makarov, Nikola Unkovic, Aleksandar Kneževic, željko Savkovic, Milica Ljaljevic Grbic, Jelena Vukojevic, Zvezdana Jovanovic, Luka R LucicAbstract:: Members of the millipede order Julida rely on dominantly quinonic Defensive Secretions with several minor, non-quinonic components. The free radical-scavenging activities of ethanol, methanol, hexane, and dichloromethane extracts of Defensive Secretions emitted by Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) were investigated using the ABTS, DPPH, and total reducing power (TRP) tests. The obtained extracts were also tested for inhibition of acetylcholinesterase and tyrosinase activity. Finally, the antifungal potential of both julid extracts was evaluated against seven Fusarium species. Secretions of both species showed activity against free radicals, acetylcholinesterase, tyrosinase, and all of the selected fungal species. The Secretions of P. hungaricus exhibited a more potent antioxidative effect than did those of M. unilineatum, while there were no significant differences of antiacetylcholinesterase activity between the tested extracts. Only the hexane extract of M. unilineatum showed an effect on tyrosinase activity stronger than that of P. hungaricus. Fusarium sporotrichioides, F. graminearum, and F. verticillioides were the fungi most resistant to Secretions of both julids. The Fusarium species most susceptible to the secretion of P. hungaricus was F. avenaceum, while the concentrations of M. unilienatum extracts needed to inhibit and completely suppress fungal growth were lowest in the case of their action on F. lateritium. Our data support previous findings that julid Defensive Secretions possess an antimicrobial potential and reveal their antioxidative and antineurodegenrative properties. Bearing in mind the chemical complexity of the tested Defensive Secretions, we presume that they can also exhibit other biological activities.
