Effects of Incubation Temperature on the Dose–Survival Time Relationship of Trichoplusia ni Larvae Infected with Autographa Californica Nucleopolyhedrovirus

2000 ◽  
Vol 76 (3) ◽  
pp. 185-190 ◽  
Author(s):  
Nikolai van Beek ◽  
Patrick R Hughes ◽  
H.Alan Wood
Keyword(s):  
Survival Time ◽  
Trichoplusia Ni ◽  
Incubation Temperature ◽  
Autographa Californica ◽  
Time Relationship ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Relationship Of

scholarly journals Characterization of Two Autographa californica Nucleopolyhedrovirus Proteins, Ac145 and Ac150, Which Affect Oral Infectivity in a Host-Dependent Manner

2004 ◽  
Vol 78 (12) ◽  
pp. 6439-6448 ◽  
Author(s):  
Renee Lapointe ◽  
Holly J. R. Popham ◽  
Ursula Straschil ◽  
David Goulding ◽  
David R. O'Reilly ◽  
...  
Keyword(s):  
Trichoplusia Ni ◽  
Polyclonal Antibodies ◽  
Heliothis Armigera ◽  
Autographa Californica ◽  
Dependent Manner ◽  
Significant Drop ◽  
Double Deletion ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Budded Virus ◽  
Nuclear Polyhedrosis

ABSTRACT The genome of the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV) contains two homologues, orf145 and orf150, of the Heliothis armigera Entomopoxvirus (HaEPV) 11,000-kDa gene. Polyclonal antibodies raised against the Ac145 or Ac150 protein were utilized to demonstrate that they are expressed from late to very late times of infection and are within the nuclei of infected Sf-21 cells. Transmission electron microscopy coupled with immunogold labeling of Ac145 found this protein within the nucleus in areas of nucleocapsid assembly and maturation, along with some association with the enveloped bundles of virions within the developing occlusion bodies (OBs). Ac150 was found to be mainly associated with enveloped bundles of virions within OBs and also with those not yet occluded. Both Ac145 and Ac150 were found to be present in budded virus as well as OBs. Both orf145 and orf150 were deleted from the AcMNPV genome, singly or together, and these deletion mutants were assessed for oral infectivity both in Trichoplusia ni and Heliothis virescens larvae. Deletion of Ac145 led to a small but significant drop in infectivity (sixfold) compared to wild-type (wt) AcMNPV for T. ni but not for H. virescens. Deletion of Ac150 alone had no effect on infectivity of the virus for either host. However, deletion of both Ac145 and Ac150 gave a recombinant virus with a drastic (39-fold) reduction in infectivity compared to wt virus for H. virescens. Intrahemocoelic injection of budded virus from the double-deletion virus into H. virescens larvae is as infectious to this host as wt budded virus, indicating that Ac145 and Ac150 play a role in primary oral infection of AcMNPV, the extent of which is host dependent.

scholarly journals Partial redistribution of the Autographa californica nucleopolyhedrovirus chitinase in virus-infected cells accompanies mutation of the carboxy-terminal KDEL ER-retention motif

2002 ◽  
Vol 83 (3) ◽  
pp. 685-694 ◽  
Author(s):  
Giles P. Saville ◽  
Carole J. Thomas ◽  
Robert D. Possee ◽  
Linda A. King
Keyword(s):  
Post Infection ◽  
Trichoplusia Ni ◽  
Secretory Pathway ◽  
Cell Lysis ◽  
Autographa Californica ◽  
Extracellular Medium ◽  
Partial Redistribution ◽  
Er Retention ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Carboxy Terminal

During virus infection of insect cells, the Autographa californica nucleopolyhedrovirus chitinase is localized primarily within the endoplasmic reticulum (ER), which is consistent with the presence of a carboxy-terminal ER retention motif (KDEL). Release of chitinase into the extracellular medium appears to be concomitant with terminal cell lysis, rather than by active secretion. In this study, we have shown that mutation of the KDEL motif induces a partial redistribution of the chitinase at both early and late times post-infection. Deletion of the KDEL motif or substitution with glycine residues allowed chitinase to move through the secretory pathway, accumulating to detectable levels in the extracellular medium by 24 h post-infection; more than 48 h prior to cell lysis. Deletion of the KDEL motif did not compromise enzyme activity, with the modified enzyme exhibiting characteristic endo- and exo-chitinolytic activity. Trichoplusia ni larvae infected with the modified virus were found to liquefy approximately 24 h earlier than larvae infected with a control virus in which the chitinase KDEL motif had not been deleted.

scholarly journals Functional Regulation of an Autographa californica Nucleopolyhedrovirus-Encoded MicroRNA, AcMNPV-miR-1, in Baculovirus Replication

2016 ◽  
Vol 90 (14) ◽  
pp. 6526-6537 ◽  
Author(s):  
Mengxiao Zhu ◽  
Jinwen Wang ◽  
Riqiang Deng ◽  
Xunzhang Wang
Keyword(s):  
Virus Infection ◽  
Viral Infection ◽  
Trichoplusia Ni ◽  
Target Genes ◽  
Autographa Californica ◽  
Viral Gene ◽  
Virus Infectivity ◽  
Interacting Proteins ◽  
Larval Infection ◽  
Autographa Californica Nucleopolyhedrovirus

ABSTRACTAn Autographa californica nucleopolyhedrovirus-encoded microRNA (miRNA), AcMNPV-miR-1, downregulates theac94gene, reducing the production of infectious budded virions and accelerating the formation of occlusion-derived virions. In the current study, four viruses that constitutively overexpress AcMNPV-miR-1 were constructed to further explore the function of the miRNA. In addition to theac94gene, two new viral gene targets (ac18andac95) of AcMNPV-miR-1 were identified, and the possible interacting proteins were verified and tested. In the context of AcMNPV-miR-1 overexpression,ac18was slightly upregulated, andac95was downregulated. Several interacting proteins were identified, and a functional pathway for AcMNPV-miR-1 was deduced. AcMNPV-miR-1 overexpression decreased budded virus infectivity, reduced viral DNA replication, accelerated polyhedron formation, and promoted viral infection efficiency inTrichoplusia nilarvae, suggesting that AcMNPV-miR-1 restrains virus infection of cells but facilitates virus infection of larvae.IMPORTANCERecently, microRNAs (miRNAs) have been widely reported as moderators or regulators of mammalian cellular processes, especially disease-related pathways in humans. However, the roles played by miRNAs encoded by baculoviruses, which infect numerous beneficial insects and agricultural pests, have rarely been described. To explore the actions of virus-encoded miRNAs, we investigated an miRNA encoded by Autographa californica nucleopolyhedrovirus (AcMNPV-miR-1). We previously identified this miRNA through the exogenous addition of AcMNPV-miR-1 mimics. In the current study, we constitutively overexpressed AcMNPV-miR-1 and analyzed the resultant effects to more comprehensively assess what is indeed the function of this miRNA during viral infection. In addition, we widely explored the target genes for the miRNA in the viral and host genomes and proposed a possible functional network for AcMNPV-miR-1, which provides a better general understanding of virus-encoded miRNAs. In brief, our study implied that AcMNPV-miR-1 constrains viral replication and cellular infection but enhances larval infection.

scholarly journals Deletion of the Autographa californica nucleopolyhedrovirus chitinase KDEL motif and in vitro and in vivo analysis of the modified virus

2004 ◽  
Vol 85 (4) ◽  
pp. 821-831 ◽  
Author(s):  
Giles P. Saville ◽  
Alexandra L. Patmanidi ◽  
Robert D. Possee ◽  
Linda A. King
Keyword(s):  
Trichoplusia Ni ◽  
Lethal Dose ◽  
Gene Promoter ◽  
Autographa Californica ◽  
Coding Region ◽  
Insect Larvae ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Infected Cells

Infection of insect larvae with Autographa californica nucleopolyhedrovirus (AcMNPV) results in the liquefaction of the host, a process involving the action of virus-encoded chitinase and cathepsin gene products. Chitinase is localized in the endoplasmic reticulum (ER) during infection because of the presence of a C-terminal ER retrieval motif (KDEL). In this study, the KDEL coding region was removed from the chitinase gene so that expression of the modified chitinase remained under the control of its own gene promoter, at its native locus. The deletion of KDEL resulted in the redistribution of chitinase within the cell during virus infection. Chitinase lacking the KDEL motif was detectable at the plasma membrane and was also evident in the culture medium of virus-infected cells from as early as 12 h post-infection (p.i.). Secretion of chitinase from the cell continued up to 72 h p.i., until cytolysis. The biological activity of the recombinant virus in Trichoplusia ni larvae was enhanced, with a significant reduction in the lethal dose and lethal time associated with infection. Furthermore, a reduction in feeding damage caused by infected larvae was observed compared to AcMNPV-infected individuals.

scholarly journals Multiple Nucleocapsid Packaging of Autographa californica Nucleopolyhedrovirus Accelerates the Onset of Systemic Infection in Trichoplusia ni

1999 ◽  
Vol 73 (1) ◽  
pp. 411-416 ◽  
Author(s):  
Jan O. Washburn ◽  
Eric H. Lyons ◽  
Eric J. Haas-Stapleton ◽  
Loy E. Volkman
Keyword(s):  
Trichoplusia Ni ◽  
Time Course ◽  
Systemic Infection ◽  
Autographa Californica ◽  
Target Tissue ◽  
Midgut Cell ◽  
Individual Host ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Packaging Strategy ◽  
Systemic Infections

ABSTRACT Among the nucleopolyhedroviruses (Baculoviridae), the occlusion-derived virus (ODV), which initiates infection in host insects, may contain only a single nucleocapsid per virion (the SNPVs) or one to many nucleocapsids per virion (the MNPVs), but the significance of this difference is unclear. To gain insight into the biological relevance of these different packaging strategies, we compared pathogenesis induced by ODV fractions enriched for multiple nucleocapsids (ODV-M) or single nucleocapsids (ODV-S) ofAutographa californica multicapsid nucleopolyhedrovirus (AcMNPV) containing a β-galactosidase reporter gene. In time course experiments wherein newly molted fourth-instarTrichoplusia ni were challenged with doses of ODV-S or ODV-M that yielded the same final mortality (∼70%), we characterized viral foci as either being restricted to the midgut or involving tracheal cells (the secondary target tissue, indicative of systemic infection). We found that while the timing of primary infection by ODV-S and ODV-M was similar, ODV-S established significantly more primary midgut cell foci than ODV-M, but ODV-M infected tracheal cells at twice the rate of ODV-S. The more efficient establishment of tracheal infections by ODV-M decreased the probability that infections were lost by midgut cell sloughing, explaining why higher numbers of primary infections established by ODV-S within larvae were needed to achieve the same final mortality. These results showed that the multiple nucleocapsid packaging strategy of AcMNPV accelerates the onset of irreversible systemic infections and may indicate why MNPVs have wider individual host ranges than SNPVs.

scholarly journals Dual mutations in the Autographa californica nucleopolyhedrovirus FP-25 and p35 genes result in plasma-membrane blebbing in Trichoplusia ni cells

2006 ◽  
Vol 87 (3) ◽  
pp. 531-536 ◽  
Author(s):  
Barbara J. Kelly ◽  
Linda A. King ◽  
Robert D. Possee ◽  
Susan D. J. Chapple
Keyword(s):  
Plasma Membrane ◽  
Spodoptera Frugiperda ◽  
Trichoplusia Ni ◽  
Virus Production ◽  
Autographa Californica ◽  
Caspase Activation ◽  
Membrane Blebbing ◽  
Cell Blebbing ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Budded Virus

Spodoptera frugiperda cells infected with Autographa californica nucleopolyhedrovirus (AcMNPV) lacking a functional anti-apoptotic p35 protein undergo apoptosis. However, such mutants replicate normally in Trichoplusia ni (TN-368) cells. An AcMNPV plaque isolate (AcdefrT) was identified during propagation of a virus deficient in p35 in TN-368 cells. This virus exhibited enhanced budded-particle formation in TN-368 cells, but was partially defective for polyhedra production in the same cells. Virus replication in AcdefrT-infected TN-368 cells was accompanied by extensive plasma-membrane blebbing and caspase activation late in infection, both features of apoptosis. Rescue of the p35 locus of AcdefrT continued to result in a reduction in polyhedra and increase in budded virus production in TN-368 cells, but no plasma-membrane blebbing was observed. The mutation was mapped to the FP-25 gene locus. This gene mutation combined with the non-functional p35 was found to be responsible for the cell-blebbing effect observed in AcdefrT-infected TN-368 cells.

Mutagenesis of the active site coding region of the Autographa californica nucleopolyhedrovirus chiA gene

Microbiology ◽  
2000 ◽  
Vol 81 (5) ◽  
pp. 1403-1411 ◽  
Author(s):  
Carole J. Thomas ◽  
Graham W. Gooday ◽  
Linda A. King ◽  
Robert D. Possee
Keyword(s):  
Active Site ◽  
Trichoplusia Ni ◽  
Active Sites ◽  
Autographa Californica ◽  
Coding Region ◽  
Insect Larvae ◽  
Recombinant Viruses ◽  
Autographa Californica Nucleopolyhedrovirus ◽  
Infected Insect ◽  
Aspartate Residue

The chitinase of Autographa californica nucleopolyhedrovirus (AcMNPV) is required for the characteristic liquefaction of baculovirus-infected insect larvae. Alignments of the putative active sites of a range of chitinases revealed two highly conserved residues, glutamate and aspartate, which have been proposed to constitute the catalytic residues of the active site. These residues were mutated in the AcMNPV chitinase. Three recombinant viruses were generated, AcchiA D311G, AcchiA E315G and AcchiA D311G E315G, which contained mutations at either the glutamate, the aspartate or both. It was demonstrated that chitinase protein production was unaffected by the mutation of these residues. However, mutation of both residues resulted in the attenuation of chitinolytic activity and the cessation of liquefaction of Trichoplusia ni larvae infected with AcchiA D311G E315G. Mutagenesis of the glutamate residue led to a reduction in exochitinase activity and a delay in the appearance of endochitinase activity. In addition, larvae infected with this virus, AcchiA E315G, liquefied more slowly than those larvae infected with wild-type AcMNPV. Mutagenesis of the aspartate residue resulted in a reduction of exochitinase activity but an unexpected enhancement of endochitinolytic activity. Liquefaction of AcchiA D311G-infected larvae was observed at the same time as that of AcMNPV-infected larvae.

scholarly journals Bacmid Expression of Granulovirus Enhancin En3 Accumulates in Cell Soluble Fraction to Potentiate Nucleopolyhedrovirus Infection

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1233
Author(s):  
Adriana Ricarte-Bermejo ◽  
Oihane Simón ◽  
Ana Beatriz Fernández ◽  
Trevor Williams ◽  
Primitivo Caballero
Keyword(s):  
Trichoplusia Ni ◽  
Recombinant Virus ◽  
Spodoptera Exigua ◽  
Insect Cells ◽  
Soluble Fraction ◽  
Autographa Californica ◽  
Insect Midgut ◽  
Baculovirus Infection ◽  
Occlusion Bodies ◽  
Infected Cells

Enhancins are metalloproteinases that facilitate baculovirus infection in the insect midgut. They are more prevalent in granuloviruses (GVs), constituting up to 5% of the proteins of viral occlusion bodies (OBs). In nucleopolyhedroviruses (NPVs), in contrast, they are present in the envelope of the occlusion-derived virions (ODV). In the present study, we constructed a recombinant Autographa californica NPV (AcMNPV) that expressed the Trichoplusia ni GV (TnGV) enhancin 3 (En3), with the aim of increasing the presence of enhancin in the OBs or ODVs. En3 was successfully produced but did not localize to the OBs or the ODVs and accumulated in the soluble fraction of infected cells. As a result, increased OB pathogenicity was observed when OBs were administered in mixtures with the soluble fraction of infected cells. The mixture of OBs and the soluble fraction of Sf9 cells infected with BacPhEn3 recombinant virus was ~3- and ~4.7-fold more pathogenic than BacPh control OBs in the second and fourth instars of Spodoptera exigua, respectively. In contrast, when purified, recombinant BacPhEn3 OBs were as pathogenic as control BacPh OBs. The expression of En3 in the soluble fraction of insect cells may find applications in the development of virus-based insecticides with increased efficacy.

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