Plant-mediated alteration of the peritrophic matrix and baculovirus infection in lepidopteran larvae

Plymale, Ruth; Grove, Michael; Cox-Foster, Diana; Ostiguy, Nancy; Hoover, Kelli

doi:10.1016/j.jinsphys.2008.02.005

Cited by 54 publications

(33 citation statements)

References 49 publications

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“…Samples were secondarily fixed in 1% osmium tetroxide for 1 h, rinsed three times in cacodylate buffer for 5 min (each), and dehydrated through an ethanol series (15). Following ethanol dehydration, midgut samples from three to four larvae were freeze-fractured in liquid nitrogen for scanning electron microscopy (SEM) as described by Plymale et al (26). SDS-PAGE and Western blot analysis.…”

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confidence: 99%

Bacillus thuringiensisBel Protein Enhances the Toxicity of Cry1Ac Protein toHelicoverpa armigeraLarvae by Degrading Insect Intestinal Mucin

Fang

Wang

Guo

et al. 2009

Appl Environ Microbiol

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Bacillus thuringiensis has been used as a bioinsecticide to control agricultural insects. Bacillus cereus group genomes were found to have a Bacillus enhancin-like (bel) gene, encoding a peptide with 20 to 30% identity to viral enhancin protein, which can enhance viral infection by degradation of the peritrophic matrix (PM) of the insect midgut. In this study, the bel gene was found to have an activity similar to that of the viral enhancin gene. A bel knockout mutant was constructed by using a plasmid-free B. thuringiensis derivative, BMB171. The 50% lethal concentrations of this mutant plus the cry1Ac insecticidal protein gene were about 5.8-fold higher than those of the BMB171 strain. When purified Bel was mixed with the Cry1Ac protein and fed to Helicoverpa armigera larvae, 3 g/ml Cry1Ac alone induced 34.2% mortality. Meanwhile, the mortality rate rose to 74.4% when the same amount of Cry1Ac was mixed with 0.8 g/ml of Bel. Microscopic observation showed a significant disruption detected on the midgut PM of H. armigera larvae after they were fed Bel. In vitro degradation assays showed that Bel digested the intestinal mucin (IIM) of Trichoplusia ni and H. armigera larvae to various degrading products, similar to findings for viral enhancin. These results imply Bel toxicity enhancement depends on the destruction of midgut PM and IIM, similar to the case with viral enhancin. This discovery showed that Bel has the potential to enhance insecticidal activity of B. thuringiensis-based biopesticides and transgenic crops.

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confidence: 99%

Bacillus thuringiensisBel Protein Enhances the Toxicity of Cry1Ac Protein toHelicoverpa armigeraLarvae by Degrading Insect Intestinal Mucin

Fang

Wang

Guo

et al. 2009

Appl Environ Microbiol

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“…Following collection of haemolymph samples from orally inoculated larvae, cadavers were dissected and processed for LacZ signalling as described previously (Plymale et al, 2008). Each cadaver was examined and scored for the presence and number of (i) infected midgut cells only, (ii) infected midgut plus associated tracheal epidermal cells, and (iii) infected midgut-associated tracheal epidermal cells only.…”

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confidence: 99%

Pathogenesis of Lymantria dispar multiple nucleopolyhedrovirus in L. dispar and mechanisms of developmental resistance

McNeil

Cox-Foster

Gardner

et al. 2010

Journal of General Virology

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Lymantria dispar has a long historical association with the baculovirus Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV), which is one of the primary population regulators of L. dispar in the field. However, host larvae exhibit strong developmental resistance to fatal infection by LdMNPV; the LD 50 in newly moulted fourth instars is 18-fold lower than in the middle of the instar (48-72 h post-moult). Using a recombinant of LdMNPV expressing lacZ, we examined the key steps of pathogenesis in the host to explore mechanisms of developmental resistance. At the midgut level, we observed reduced primary midgut infections in mid-fourth instars, indicating increased sloughing of infected cells. Additional barriers were observed as the virus escaped the midgut. Mid-fourth instars had higher numbers of melanized foci of infection associated with the midgut, apoptotic tracheal epidermal cells and haemocytes, and reduced numbers of infected haemocytes later in infection. Our results show that the co-evolutionary relationship between L. dispar and LdMNPV has resulted in both midgut-based and systemic antiviral defences and that these defences are age-dependent within the instar. This age-related susceptibility may contribute to how the virus is maintained in nature and could influence management of L. dispar by using the virus.

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“…Está compuesta de microfibras de quitina, proteoglicanos y proteínas (Lehane 1997) y tiene como función proteger al intestino medio de la abrasión del material vegetal consumido y de microorganismos y sustancias químicas. Su grosor se ve influenciado por el tipo de follaje consumido por los insectos, lo que puede afectar la capacidad de ingreso de los baculovirus (Plymale et al, 2008), los cuales usan la actividad de sus proteínas quitinasas y enhancinas para romper la membrana y de esta forma iniciar la infección de las células intestinales (Wang y Granados 2000).…”

Section: Mecanismos De Especificidadunclassified

Baculovirus: Hospederos y especificidad

Valderrama¹,

Villamizar²

2013

Rev. Colomb. Biotecnol.

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ResumenLos baculovirus son virus patógenos de insectos ampliamente empleados a nivel mundial como bioinsecticidas para el control de diferentes plagas de importancia agrícola y más recientemente como vectores de expresión de proteínas y vectores para terapia génica. Una de sus características principales es su alta especificidad de hospedero que incluye un rango muy estrecho de especies de insectos, que a menudo pertenecen a la misma familia. Sin embargo, es necesario entender los mecanismos involucrados en la definición del rango de hospederos de los baculovirus con el fin de evaluar la seguridad e inocuidad de su uso y determinar la posibilidad de mejorar sus propiedades para aplicaciones biotecnológicas mediante la construcción de baculovirus recombinantes con diferentes rangos de hospederos. En el presente artículo se revisarán los principales mecanismos comprendidos en la definición del rango de hospederos de los baculovirus, dentro de los que se destacan la especificidad para entrar en las células, la posibilidad de replicación del genoma viral, el control de los procesos bioquímicos y moleculares del insecto y las interacciones virus-hospedero que regulan la multiplicación del agente infeccioso, así como las perspectivas de la aplicación de este conocimiento.Palabras clave: infección viral, rango de hospederos, evolución, resistencia. AbstractBaculoviruses are insect pathogenic viruses widely used as bioinsecticides for controlling of several agricultural important pests and more recently as protein expression vectors and gene therapy vectors. One of its main characteristics is its high host-specificity including a very narrow range of insect species, which often belong to the same family. However, to understand the mechanisms involved in the definition of baculoviruses host range is necessary in order to assess the security and safety of its use and to determine the possibility of improving their properties for biotechnological applications through the construction of recombinant baculovirus with different host ranges. In the present article the main mechanisms involved in baculoviruses host range as specificity for entering into the host cells, the possibility of viral genome replication, the control of biochemical and molecular insect processes and the interactions virus-host regulating the multiplication of the infectious agent, and the prospects of applying this knowledge will be reviewed.

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Plant-mediated alteration of the peritrophic matrix and baculovirus infection in lepidopteran larvae

Cited by 54 publications

References 49 publications

Bacillus thuringiensisBel Protein Enhances the Toxicity of Cry1Ac Protein toHelicoverpa armigeraLarvae by Degrading Insect Intestinal Mucin

Bacillus thuringiensisBel Protein Enhances the Toxicity of Cry1Ac Protein toHelicoverpa armigeraLarvae by Degrading Insect Intestinal Mucin

Pathogenesis of Lymantria dispar multiple nucleopolyhedrovirus in L. dispar and mechanisms of developmental resistance

Baculovirus: Hospederos y especificidad

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