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Updated: Aug 12, 2026
Protocols for Oral Infection of Lepidopteran Larvae with Baculovirus
Published on: September 3, 2008
A baculovirus enhancin alters the permeability of a mucosal midgut peritrophic matrix from lepidopteran larvae
J Peng1, J Zhong, R R Granados
1Boyce Thompson Institute for Plant Research at Cornell University, 223 Boyce Thompson Institute, Ithaca, USA
Abstract:
The peritrophic matrix (PM) in lepidopterous larvae may function as a defensive barrier against ingested viral pathogens. PMs isolated from Trichoplusia ni and Pseudaletia unipuncta larvae, were treated with a baculovirus-encoded metalloprotease (enhancin) from Trichoplusia ni granulosis virus (TnGV) and their in vitro permeability to blue dextran and fluorescent-labelled Autographa californica nuclear polyhedrosis virus (AcMNPV) was determined using a dual chamber permeability apparatus. Incubation of T. ni PMs with 0.0, 0.5, 1.0, and 2.0mg/ml enhancin resulted in a blue dextran 2000 flux of 4.4, 6.3, 9.9, and 15.6&mgr;g/mm(2)/h, respectively. In addition, T. ni PMs treated with enhancin were found to be significantly more permeable to fluorescent-labelled AcMNPV than non-treated control PMs. The permeability of T. ni PMs treated with 3.0mg/ml enhancin was 0.017 cumulative percent crossing/mm(2)/h, whereas the permeability of the control PM was below the detectable limit. Similarly, enhancin treatment greatly increased the permeability of P. unipuncta PMs to AcMNPV. These results provide evidence that the PM from two lepidopteran species can block the passage of baculovirions across this matrix thus reducing the probability of larval infection. Furthermore, these results support the hypothesis that enhancin facilitates NPV infection of larvae by altering the permeability of the PM.
Insights
The peritrophic matrix in insect larvae acts as a barrier against viruses. Enhancin, a viral enzyme, increases the matrix
Area of Science:
- Insect pathology
- Molecular biology
- Virology
Background:
- The peritrophic matrix (PM) in lepidopteran larvae is a potential barrier against ingested viral pathogens.
- Baculoviruses are significant pathogens of lepidopteran larvae, and their infection mechanisms are of economic and ecological importance.
Purpose of the Study:
- To investigate the role of the peritrophic matrix (PM) as a barrier against baculovirus infection in lepidopteran larvae.
- To determine if enhancin, a baculovirus-encoded metalloprotease, affects the permeability of the PM to baculoviruses.
Main Methods:
- Isolation of PMs from *Trichoplusia ni* and *Pseudaletia unipuncta* larvae.
- In vitro permeability assays using blue dextran and fluorescent-labeled *Autographa californica* nuclear polyhedrosis virus (AcMNPV).
- Treatment of PMs with varying concentrations of enhancin from *Trichoplusia ni* granulosis virus (TnGV).
Main Results:
- Enhancin treatment significantly increased the permeability of *T. ni* PMs to blue dextran in a dose-dependent manner.
- PMs treated with enhancin showed significantly higher permeability to fluorescent-labeled AcMNPV compared to untreated controls.
- Enhancin treatment also increased the permeability of *P. unipuncta* PMs to AcMNPV.
Conclusions:
- The peritrophic matrix (PM) from lepidopteran larvae acts as a physical barrier, limiting baculovirus passage and reducing larval infection probability.
- Enhancin facilitates baculovirus infection by increasing the permeability of the PM, thereby enhancing viral entry into the insect host.
