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  • Heliothis virescens  (5)
  • Cytochalasin D  (2)
  • Springer  (7)
  • 1
    ISSN: 1570-7458
    Keywords: Secondary plant compounds ; 2,5-dihydroxymethyl ; 3,4-dihydroxypyrrolidine ; Spodoptera littoralis ; S. exempta ; Heliothis virescens ; Schistocerca gregaria ; Locusta migratoria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Récemment a été mis en évidence le puissant pouvoir inhibiteur de différents glucosidases. Présenté par l'amino-alditol cyclique, 2,5 dihydroxymethyl 3,4 dihydroxypyrrolidine (DMDP), isolé de graines de la légumineuse Lonchocarpus sericeus. Nous avons examiné le rôle de ce composé secondaire dans la stratégie défensive de la plante contre une gamme d'insectes phytophages, à travers son action sur le développement, le comportement alimentaire et le fonctionnement des récepteurs gustatifs. Nous avons montré que DMDP peut inhiber, suivant la dose, la prise de nourriture et, qu'apr⪻s ingestion (par Spodoptera spp), il peut agir comme une toxine. Par suite de sa structure moléculaire, DMDP peut être considéré, non seulement comme l'analogue d'un sucre, mais aussi comme un alcaloïde. Le bilan des résultats de nos expériences suggère que l'efficacité de DMDP comme phagodissuadant, si elle ne provient pas de sa toxicité, découle principalement de ses propriétés d'alcaloïde.
    Notes: Abstract The cyclic amino alditol 2,5-dihydroxymethyl 3,4-dihydroxypyrrolidine (DMDP) has recently been shown to be an inhibitor of various glucosidases. We have investigated its role as a plant protective chemical against a range of phytophagous insects by examining its effects on development, feeding behaviour and functioning of taste receptors. We have shown that it can inhibit feeding and can be toxic. The mechanisms by which these effects are achieved are discussed in the context of the molecular structure of the compound.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 49 (1988), S. 111-121 
    ISSN: 1570-7458
    Keywords: Spodoptera littoralis ; Heliothis virescens ; H. armigera ; electrophysiology ; feeding behaviour ; adults ; larvae ; proboscis sensilla ; antifeedants ; phagostimulants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adults and larvae of Spodoptera littoralis, Heliothis virescens and Heliothis armigera were tested with a range of sugars, amino acids, sugar alcohols and allelochemics. Feeding behaviour was correlated with the electrophysiological responses of maxillary styloconic sensilla in the larvae and proboscis styloconic sensilla in the adult. The neural response was more vigorous in larvae than in adults but otherwise the spectra of responses were similar in the two life stages. Phagostimulants and antifeedants stimulated maximally different sensilla in larvae but not in adults. The responses of adult sensilla to sugars and amino acids were significantly correlated to behaviour in all three species, but only in H. armigera was there a similar correlation with the sugar alcohols and allelochemics.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 55 (1990), S. 149-160 
    ISSN: 1570-7458
    Keywords: Spodoptera littoralis ; Spodoptera frugiperda ; Heliothis virescens ; Heliothis armigera ; azadirachtin ; salannin ; limonoids ; antifeedants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'activité phagodissuadante de l'azadirachtine, de ses dérivés et des limonoïdes voisins sur 4 espèces de lépidoptères: Spodoptera littoralis, S. frugiperda, Heliothis virescens et H. armigera a été évaluée par des expériences avec et sans choix. Les expériences de choix ont montré que le comportement alimentaire de S. littoralis était modifié par plus de substances que celui de S. frugiperda ou H. virescens. Celui de H. armigera était le moins modifié. Les 2 substances les plus puissantes parmi les 40 examinées, ont été l'azadirachtine et le dihydroazadirachtine. Ces résultats montrent que l'hydrogénation de la double liaison C-22,23 ne réduit pas l'activité phagodissuadante et que la nature des substitutions en C-1, C-3 et C-11 sont importantes. Les molécules avec des substitutions volumineuses en C-22 ou C-23 sont généralement des phagodissuadants aussi inefficaces que ceux ayant perdu un époxide. Les substances notées comme phagodissuadants actifs dans les expériences de choix ne sont pas toujours aussi actives en absence de choix. La valeur des tests dans l'évaluation du mode d'action des substances est discuté.
    Notes: Abstract The antifeedant activity of azadirachtin, azadirachtin-derivatives and related limonoids was assessed in choice and no-choice bioassays against four species of Lepidoptera: Spodoptera littoralis, Spodoptera frugiperda, Heliothis virescens and Heliothis armigera. The choice bioassay showed that the feeding behaviour of S. littoralis was affected by more of the compounds than that of either S. frugiperda or H. virescens. H. armigera was the least affected. Azadirachtin and dihydroazadirachtin were the most potent of the 40 compounds tested. The results showed that hydrogenation of the C-22,23 double bond did not decrease antifeedant activity and the nature of the substitutes at C-1, C-3 and C-11 were important. Molecules with bulky substitutes at either C-22 or C-23 were usually ineffective antifeedants as were compounds lacking an epoxide. Compounds recorded as active antifeedants in the choice bioassay were not always as active in the no-choice test. The value of the bioassays in assessing the mode of action of the compounds is discussed.
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  • 4
    ISSN: 1570-7458
    Keywords: Azadirachtin ; Spodoptera littoralis ; Spodoptera frugiperda ; Heliothis virescens ; growth disruption ; oral cannulation ; abdominal injection ; topical application
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Spodoptera littoralis, S. frugiperda et Heliothis virescens ont été exposés à l'azadirachtine et 23 autres substances voisines dans 3 expériences: canulation orale, injection d'haemolymphe et application topique. S. littoralis est sensible à un plus grand nombre de substances que les 2 autres espèces. De toutes façons, les substances les plus actives ont été l'azadirachtine, la 22,23-dihydroazadirachtine et la 1-détigloyl-22,23-dihydroazadirachtine. La nature des substitutions en C-1 et C-3 de l'anneau décaline modifie la puissance des substances, tout comme les substitutions en C-22,23. D'une façon générale, les chenilles ont été moins sensibles aux applications topiques qu'aux canulations dans le tube digestif ou aux injections dans l'haemolymphe.
    Notes: Abstract Spodoptera littoralis, Spodoptera frugiperda and Heliothis virescens were exposed to azadirachtin and 23 other related compounds in three bioassays: oral cannulation, haemolymph injection and topical application. Spodoptera littoralis was susceptible to a larger proportion of the compounds than either of the other species. Overall, azadirachtin, 22,23-dihydroazadirachtin and 1-detigloyl-22,23-dihydroazadirachtin were the most active compounds. The nature of the substitutes at C-1 and C-3 of the decalin ring affects the potency of the compounds, as does the addition of substitutes to C-22,23. Generally, larvae were less sensitive to compounds when they were topically applied than when they were cannulated into the gut or injected into the haemolymph.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 183 (1994), S. 67-76 
    ISSN: 1615-6102
    Keywords: Actin microfilaments ; Brassica napus ; Cytochalasin D ; Pollen development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The organization of actin microfilaments (MFs) was studied during pollen development ofBrassica napus cv. Topas. Cells were prepared using three techniques and double labelled for fluorescence microscopy with rhodamine-labelled phalloidin for MFs and Hoechst 33258 for DNA. Microfilaments are present at all stages of pollen development with the exception of tricellular pollen just prior to anthesis. Unicellular microspores contain MFs which radiate from the surface of the nuclear envelope into the cytoplasm. During mitosis MFs form a network partially surrounding the mitotic apparatus and extend into the cytoplasm. Both cytoplasmic and phragmoplast-associated MFs are present during cytokinesis. Nuclear associated-, cytoplasmic, and randomly oriented cortical MFs appear in the vegetative cell of the bicellular microspore. Cortical MFs in the vegetative cell organize into parallel MF bundles (MFBs) aligned transverse to the furrows. The MFBs disappear prior to microspore elongation. At anthesis MFs are restricted to the cortical areas subjacent to the furrows of the vegetative cell. The use of cytochalasin D to disrupt MF function resulted in: (1) displacement of the acentric nucleus in the unicellular microspore; (2) displacement of the spindle apparatus in the mitotic cell; (3) symmetrical growth of the bicellular microspore rather than elongation and (4) inhibition of pollen tube germination in the mature pollen grain. This suggests that MFs play an important role in anchoring the nucleus in the unicellular microspore as well as the spindle apparatus during microspore mitosis, in microspore shape determination and in pollen tube germination.
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  • 6
    ISSN: 1615-6102
    Keywords: Actin microfilament ; Brassica napus ; Cytochalasin D ; Microspore embryogenesis ; Microtubule ; Preprophase band
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in the actin filament and microtubule cytoskeleton were examined during heat- and cytochalasin D-induced embryogenesis in microspores ofBrassica napus cv. Topas by rhodamine phalloidin and immunofluorescence labelling respectively. The nucleus was displaced from its peripheral to a more central position in the cell, and perinuclear actin microfilaments and microtubules extended onto the cytoplasm. Heat treatment induced the formation of a preprophase band of microtubules in microspores; preprophase bands are not associated with the first pollen mitosis. Actin filament association with the preprophase band was not observed. The orientation and position of the mitotic spindle were altered, and it was surrounded with randomly oriented microfilaments. The phragmoplast contained microfilaments and microtubules, as in pollen mitosis I, but it assumed a more central position. Cytoskeletal reorganisation also occurred in microspores subjected to a short cytochalasin D treatment, in the absence of a heat treatment. Cytochalasin D treatment of microspores resulted in dislocated mitotic spindles, disrupted phragmoplasts, and symmetric divisions and led to embryogenesis, confirming that a normal actin cytoskeleton has a role in preventing the induction of embryogenesis.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 16 (1990), S. 3167-3196 
    ISSN: 1573-1561
    Keywords: Spodoptera littoralis ; Spodoptera exempta ; Heliothis virescens ; Helicoverpa armigera ; Lepidoptera ; Noctuidae ; polyhydroxy alkaloids ; piperidine ; pyrrolidine ; castanospermine ; swainsonine ; alexine ; fagomine ; behavior ; electrophysiology ; receptor mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Eleven polyhydroxy alkaloids of plant origin were tested for anti-feedant effects against larvae of the lepidopteransSpodoptera littoralis, Spodoptera frugiperda, Heliothis virescens, andHelicoverpa armigera. Data from behavioral and electrophysiological investigations were correlated to reveal information on the mode of action of the antifeedants. The pyrrolidine DMDP was an effective antifeedant for all four species, whereas the piperidines fagomine and XZ-1 and the pyrrolizidine alexine were all ineffective as antifeedants. The activity of the pyrrolidines CYB-3 and DAB-1, the piperidines DNJ, DMJ, and BR1, and the bicyclic octahydroindolizine castanospermine varied among species. The investigation focuses on the structural similarities between some of the alkaloids and some common phagostimulatory sugars and illustrates a neural interaction involving the neurons that are differentially responsive to alkaloids and sugars. InS. littoralis, the neurons responding specifically to the alkaloids DMDP, DAB-1, and castanospermine and to the sugars fructose, sucrose, and glucose are more active when the compounds are applied singly than when an alkaloid and a sugar are applied together. The implications for the occurrence and functioning of different sugar receptor sites are discussed.
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