Nucleopolyhedrovirus infected central nervous system cells of Bombyx mori (L.) (Lepidoptera: Bombycidae)

Torquato, Ednéia Fátima Brambilla; Neto, Marcílio Hübner de Miranda; Brancalhão, Rose Meire Costa

doi:10.1590/s1519-566x2006000100010

Cited by 22 publications

(36 citation statements)

References 17 publications

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“…The cytopathology of BmMNPV infections are similar to those in other target tissues (Brancalhão et al, 2002b, Brancalhão andRibeiro, 2003;Torquato et al, 2006a;Pereira et al, 2008). in the infected cells, the nucleus initially appears as an electron dense virogenic stroma (viroplasm), where the nucleocapsids are produced ( Figure 3A).…”

Section: Resultssupporting

confidence: 68%

“…This difference in the infection times is characteristic of NPV infections. They actually occur owing to such factors as the isolate's virulence, amount of ingested virus, larval instar, incidence of other pathogens, and ambient rearing conditions, mainly temperature, population density, and food availability (Adams and McClintock, 1991;Torquato et al, 2006a). We also need to consider the strains of B. mori larvae, which can show a remarkable difference regarding resistance to BmNPV (Ponnuvel et al, 2003;Yao et al, 2003;Nakazawa et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

“…BVs from tracheal cells reach the silk gland cytoplasm and in the nucleus of these cells establish a new reproductive cycle until the formation of the polyhedra. The role of the tracheal system as an infection-spreading organ was described previously for larval nucleopolyhedrovirus infection (Rahman and Gopinathan, 2004;Torquato et al, 2006a;Pereira et al, 2008).…”

Section: Resultsmentioning

confidence: 99%

“…BmMNPV infects the tegument, tracheae, midgut, fatty tissue, central nervous system, and testis cells (Brancalhão et al, 2002b;Brancalhão and Ribeiro, 2003;Torquato et al, 2006a;Pereira et al, 2008), but there is nothing known about silk gland susceptibility. Some studies showed the susceptibility of B. mori silk gland cells to BmNPV (Rahman and Gopinathan, 2004;Khurad et al, 2005); however, Acharya et al (2002) reported that the silk gland is not infected by BmNPV.…”

Section: Introductionmentioning

confidence: 99%

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Cytopathology of Bombyx mori (Lepidoptera: Bombycidae) silk gland caused by multiple nucleopolyhedrovirus

Brancalhão

Torquato²,

Fernandez³

2009

Genet. Mol. Res.

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ABSTRACT.A multiple nucleopolyhedrovirus previously isolated from infected Bombyx mori L. larvae (BmMNPV) in Paraná State, Brazil, was inoculated into B. mori larvae to examine susceptibility and cytopathology in silk gland cells. The anterior, middle and posterior silk glands were removed from the infected silkworm at different times post-inoculation and processed for cytopathology studies by light and transmission electron microscopy. BmMNPV infection was only detected at 72 h post-inoculation in cells of the middle and posterior silk glands. No sign of infection was found in the anterior silk gland. Cytopathological characteristics were similar to those found in other target tissues; initially, they consisted of nuclear hypertrophy and the formation of virogenic stroma (viroplasm), in which the progeny virions are produced. The virions are then enveloped and occluded in protein crystal structures, the polyhedra. After viral replication, cells undergo lysis and release a great number of BmMNPV polyhedra into the hemocoele. Histopathology showed early infection foci in regions surrounding trachea insertions, demonstrating that trachea is an infection-spreading organ in the insect body. Trachea penetrates the middle and posterior silk gland basal lamina, considered a barrier to virus, facilitating the penetration of budded virus. The anterior silk gland does not have tracheal insertions into the basal lamina, which reduces budded virus infection. Tracheal branches provide a conduit for non-occluded virions (budded virus) to pass through the basal lamina barrier and disseminate BmMNPV in the silkworm silk gland.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cytopathology of Bombyx mori (Lepidoptera: Bombycidae) silk gland caused by multiple nucleopolyhedrovirus

Brancalhão

Torquato²,

Fernandez³

2009

Genet. Mol. Res.

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“…The trachea is responsible for aeration, and a series of studies have demonstrated its role in the spread of infection by baculovirus, including the BmNPV in the insect body (BRANCALHÃO et al, 2009;KIRKPATRICK et al, 1994;PEREIRA et al, 2008;RAHMAN;GOPINATHAN, 2004;TORQUATO et al, 2006). The epidermal cells of the tracheal epithelium are organized morphologically and form a type of common lymphatic system, which acts as a virus-crossing canal, thus permitting the rapid attainment of the pathogen to organic systems.…”

Section: Regarding Virus Infection Strand and Pechmentioning

confidence: 99%

Mulberry leaves treated with bordeaux mixture protect silkworm caterpillars against fungal and viral diseases

et al. 2016

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The bordeaux mixture is used as a natural agricultural fungicide, and its application in sericulture can benefit the production of silkworm cocoons, Bombyx mori (Lepidoptera: Bombycidae). The aim of this study was to verify whether the bordeaux mixture exerts a protective effect in B. mori against fungal and viral diseases. This experiment was performed during two seasons, autumn and spring, in which 7,500 caterpillars were used at the beginning of the third instar and divided into five groups, with three repetitions of 500 individuals each. In the three groups, the caterpillars were fed leaves of Mulberry (Morus spp.) that were enriched with an aqueous bordeaux mixture solution at concentrations of 5, 10 and 20%. One group was fed exclusively mulberry leaves (control), and another was fed leaves that were moistened with water. Fungal contamination was evaluated in the integumentary surface of the insect and the mulberry leaves in the bed of creation by checking the number of colony-forming units (CFU). In the analysis of viral contamination, 20 caterpillars from each group at the beginning of the fifth instar were inoculated with 10 µl of a suspension of Bombyx mori nucleopolyhedrovirus (BmNPV). Daily, from the second to the ninth day after inoculation (dai), two caterpillars of each group were anesthetized and formalin-fixed 7% for microscopic processing and viral cytopathology analysis. A completely randomized design was used, and the CFU were compared by Tukey test with 5% significance. The results showed a decrease of 55.1% in CFU present on the mulberry leaves in the fall, when the 5% bordeaux mixture solution was used. There was no significant difference between the groups based on the bordeaux mixture in this period. During the same period, reductions of CFU of 28.5, 74.9 and 74.4% were verified in the integument of B. mori when bordeaux mixture solutions of 5, 10 and 20% were used, respectively, compared with the data that were obtained in the control group. In the spring, no difference was observed between the groups that received bordeaux mixture solution and the control. In the case of BmNPV, the 10% bordeaux mixture solution promoted greater resistance to viral infection, possibly favoring the activation of defense mechanisms of insects. Therefore, we recommend the use of a 10% bordeaux mixture solution in mulberry leaves to control fungal and viral diseases in silkworm rearing. ResumoA calda bordalesa é um produto usado como fungicida agrícola natural e sua aplicação em sericicultura pode beneficiar a produção de casulos do bicho-da-seda, Bombyx mori (Lepidoptera: Bombycidae). O objetivo deste estudo foi verificar se a calda bordalesa exerce efeito protetor em B. mori contra doenças fúngicas e virais. O experimento foi realizado em dois períodos sazonais, outono e primavera, sendo utilizadas 7.500 lagartas no início do terceiro instar, divididas em cinco grupos, com três repetições de 500 indivíduos cada. Em três grupos as lagartas foram alimentadas com folhas de amoreira (Morus spp.) enri...

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Nanoparticle-induced morphological transition of Bombyx mori nucleopolyhedrovirus: a novel method to treat silkworm grasserie disease

Das

Bhattacharya

Debnath

et al. 2013

Appl Microbiol Biotechnol

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Grasserie, a polyorganotrophic disease caused by Bombyx mori nucleopolyhedrovirus (BmNPV), accounts for lethal infection to fifth instar silkworm larvae. It was found that nanoparticle (NP)-induced morphological transformation of BmNPV polyhedra could reduce the infectivity of BmNPV both in cell line and in silkworm larvae. Initially, 11 NPs were screened for evaluation of their nature of interaction with polyhedra surface through scanning electron microscopy. Amongst these NPs, lipophilically coated silica nanoparticle (SNPL), alumina nanoparticles in the hexagonal close-packed α structure and aspartate capped gold nanoparticle transformed polyhedra were tested for their infectivity in B. mori cell line using cytopathic effect and plaque reduction assay. SNPL was evaluated for its bio-efficacy in fifth instar silkworm larvae. The study of polyhedra morphology as a function of NP concentration showed severe 'roughening' of the polyhedra with replacement of the regular facets by a large number of irregular ones by SNPL, and this caused transition of highly infectious polyhedra into a nearly spherical, non-infectious structure. A moderate polyhedra roughening was observed for alumina NPs, and no roughening was noticed for gold NPs. The morphological changes could be correlated with reduction of virus-induced cytopathic effect and plaque formation, and increased survival rate of SNPL transformed polyhedra infected silkworm larvae to 70.09±6.61% after 96 h. In this group, 61.04±8.03% larvae formed normal cocoons from which moths eclosed, laid eggs and larvae emerged. This study could lead to open up newer pathways for designing nano pharmaceuticals to combat other viral diseases.

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Nucleopolyhedrovirus infected central nervous system cells of Bombyx mori (L.) (Lepidoptera: Bombycidae)

Cited by 22 publications

References 17 publications

Cytopathology of Bombyx mori (Lepidoptera: Bombycidae) silk gland caused by multiple nucleopolyhedrovirus

Cytopathology of Bombyx mori (Lepidoptera: Bombycidae) silk gland caused by multiple nucleopolyhedrovirus

Mulberry leaves treated with bordeaux mixture protect silkworm caterpillars against fungal and viral diseases

Nanoparticle-induced morphological transition of Bombyx mori nucleopolyhedrovirus: a novel method to treat silkworm grasserie disease

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