1887

Abstract

We have characterized infection and pathogenesis of an M nucleopolyhedrovirus recombinant, AcMNPV-/, carrying the reporter gene, in penultimate (fifth) instar . Bioassays revealed that while <0·1 p.f.u. of budded virus was required to generate an LD by intrahaemocoelic injection, approximately 6000 occlusions were required orally to achieve the same mortality in newly moulted fifth instar (5) larvae. In pathogenesis experiments, 78 % of the 5 larvae inoculated orally with 6000 occlusions of AcMNPV-/ were LacZ-positive at 8 h post-inoculation (p.i.) and 50 % had LacZ signals in tracheal cells indicating that in these larvae infection had been transmitted from the midgut to secondary target cells. At 24 h p.i., maximum numbers of midgut and midgut-associated tracheal foci were observed (mean of 35 foci per infected larva), and 88 % of the larvae were LacZ-positive. The extremely low foci-per-occlusion ratio (0·006) indicated that successful infection of midgut cells was the primary barrier to fatal infection. A second barrier involved the loss of infected tracheal cells associated with the midgut. At 24 h p.i., 88 % of the inoculated larvae had a systemic infection, but in bioassays only 51 % succumbed to polyhedrosis disease. The absence of melanized tracheal cells in the insects throughout the time-course suggested that the larvae that cleared their infections (38 %) did so by a mechanism other than a classical immune response.

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2003-08-01
2021-01-27
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References

  1. Adams J. R., McClintock J. T.. 1991; Baculoviridae . Nuclear polyhedrosis viruses. Part 1. Nuclear polyhedrosis viruses of insects. In Atlas of Invertebrate Viruses Edited by Adams J. R., Bonami J. R.. Boca Raton, FL: CRC Press;
    [Google Scholar]
  2. Argauer R., Shapiro M.. 1997; Fluorescence and relative activities of stilbene optical brighteners as enhancers for the gypsy moth (Lepidoptera: Lymantriidae) baculovirus. J Econ Entomol90:416–420
    [Google Scholar]
  3. Clarke T. E., Clem R. J.. 2002; Lack of involvement of haemocytes in the establishment and spread of infection in Spodoptera frugiperda larvae infected with the baculovirus Autographa californica M nucleopolyhedrovirus by intrahaemocoelic injection. J Gen Virol83:1565–1572
    [Google Scholar]
  4. Engelhard E. K., Volkman L. E.. 1995; Developmental resistance in fourth instar Trichoplusia ni orally inoculated with Autographa californica M nuclear polyhedrosis virus. Virology209:384–389
    [Google Scholar]
  5. Engelhard E. K., Kam-Morgan L. N., Washburn J. O., Volkman L. E.. 1994; The insect tracheal system: a conduit for the systemic spread of Autographa californica M nuclear polyhedrosis virus. Proc Natl Acad Sci U S A91:3224–3227
    [Google Scholar]
  6. Faulkner P., Kuzio J., Williams G. V., Wilson J. A.. 1997; Analysis of p74 , a PDV envelope protein of Autographa californica nucleopolyhedrovirus required for occlusion body infectivity in vivo . J Gen Virol78:3091–3100
    [Google Scholar]
  7. Granados R. R., Williams K. A.. 1986; In vivo infection and replication of baculoviruses. In The Biology of Baculoviruses Edited by Granados R. R., Federici B. A.. Boca Raton, FL: CRC Press;
    [Google Scholar]
  8. Hamm J. J., Styer E. L.. 1985; Comparative pathology of isolates of Spodoptera frugiperda nuclear polyhedrosis virus in Spodoptera frugiperda and Spodoptera exigua . J Gen Virol66:1249–1262
    [Google Scholar]
  9. Kirkpatrick B. A., Washburn J. O., Volkman L. E.. 1998; AcMNPV pathogenesis and developmental resistance in fifth instar Heliothis virescens . J Invertebr Pathol72:63–72
    [Google Scholar]
  10. Shapiro M., Argauer R.. 1997; Components of the stilbene optical brightener tinopal LPW as enhancers for the gypsy moth (Lepidoptera; Lymantriidae) baculovirus. J Econ Entomol90:899–904
    [Google Scholar]
  11. Stairs G. R.. 1965; Quantitative differences in susceptibility to nuclearpolyhedrosis virus among larval instars of the forest tent caterpillar, Malacosoma disstria . J Invertebr Pathol7:427–429
    [Google Scholar]
  12. Summers M. D., Smith G. E.. 1987; A Manual of Methods for Baculovirus Vectors and Insect Cell Culture Procedures . Texas Agricultural Experiment Station Bulletinno: 1555
    [Google Scholar]
  13. Trudeau D., Washburn J. O., Volkman L. E.. 2001; Central role of hemocytes in Autographa californica M nucleopolyhedrovirus pathogenesis in Heliothis virescens and Helicoverpa zea . J Virol75:996–1003
    [Google Scholar]
  14. Volkman L. E., Goldsmith P. A.. 1982; Generalized immunoassay for Autographa californica nuclear polyhedrosis virus infectivity in vitro . Appl Environ Microbiol44:227–233
    [Google Scholar]
  15. Volkman L. E., Summers M. D., Hsieh C. H.. 1976; Occluded and nonoccluded nuclear polyhedrosis virus grown in Trichoplusia ni – comparative neutralization, comparative infectivity, and in vitro growth studies. J Virol19:820–832
    [Google Scholar]
  16. Wang P., Granados R. R.. 2000; Calcofluor disrupts the midgut defense system in insects. Insect Biochem Mol Biol30:135–143
    [Google Scholar]
  17. Washburn J. O., Kirkpatrick B. A., Volkman L. E.. 1995; Comparative pathogenesis of Autographa californica M nuclear polyhedrosis virus in larvae of Trichoplusia ni and Heliothis virescens . Virology209:561–568
    [Google Scholar]
  18. Washburn J. O., Kirkpatrick B. A., Volkman L. E.. 1996; Insect protection against viruses. Nature383:767
    [Google Scholar]
  19. Washburn J. O., Kirkpatrick B. A., Haas-Stapleton E., Volkman L. E.. 1998; Evidence that the stilbene-derived optical brightener M2R enhances Autographa californica M nucleopolyhedrovirus infection of Trichoplusia ni and Heliothis virescens by preventing sloughing of infected midgut epithelial cells. Biol Control11:58–69
    [Google Scholar]
  20. Washburn J. O., Haas-Stapleton E. J., Tan F. F., Beckage N. E., Volkman L. E.. 2000; Co-infection of Manduca sexta larvae with polydnavirus from Cotesia congregata increases susceptibility to fatal infection by Autographa californica M nucleopolyhedrovirus. J Insect Physiol46:179–190
    [Google Scholar]
  21. Washburn J. O., Wong J. F., Volkman L. E.. 2001; Comparative pathogenesis of Helicoverpa zea S nucleopolyhedrovirus in noctuid larvae. J Gen Virol82:1777–1784
    [Google Scholar]
  22. Washburn J. O., Chan E. Y., Volkman L. E., Aumiller J. J., Jarvis D. L.. 2003; Early synthesis of budded virus envelope fusion protein GP64 enhances Autographa californica multicapsid nucleopolyhedrosis virulence in orally infected Heliothis virescens . J Virol77:280–290
    [Google Scholar]
  23. Zhang P., Yang K., Dai X., Pang Y., Su D.. 2002; Infection of wild-type Autographa californica multicapsid nucleopolyhedrovirus induces in vivo apoptosis of Spodoptera litura larvae. J Gen Virol83:3003–3011
    [Google Scholar]
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