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1.
Arch Insect Biochem Physiol ; 108(4): e21848, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34676595

RESUMO

Bombyx mori nucleopolyhedrovirus (BmNPV) infection causes a series of physiological and pathological changes in Bombyx mori (B. mori). Here, a metabolomic study of the innate immunity organs including hemolymph, fat body, and midgut of the silkworm strain Dazao following BmNPV challenge was conducted to reveal the metabolic variations in B. mori. Compared to the control, 4964 and 4942 features with 4077 and 4327 high-quality features were generated under positive and negative modes, respectively, from BmNPV-infected larvae. The principal component analysis and supervised learning method using partial least squares discrimination analysis demonstrated good analytical stability and experimental reproducibility of the metabolic profiles. Based on database annotations, a total of 296, 108, and 215 differential expressed metabolites (DEMs) were identified from BmNPV-infected group of hemolymph, fat body, and midgut, respectively, which were all mainly grouped into carboxylic acids and derivatives, fatty acyls, and glycerophospholipids. Kyoto Encyclopedia of Genes and Genomes Database enrichment analysis of the DEMs showed that amino acid metabolism was increased at 24 h after BmNPV infection. BmNPV induction was adopted to significantly alter a series of immune-related pathways including phospholipase D signaling pathway, FoxO signaling pathway, metabolism of xenobiotics by cytochrome P450, melanogenesis, membrane transport, carbohydrate metabolism, and lipid metabolism. The different levels of expression of several DEMs including l-glutamate, naphthalene, 3-succinoylpyridine 1-acyl-sn-glycerol 3-phosphate, and l-tyrosine which were involved in those pathways exhibited the immune responses of B. mori to BmNPV infection. Our findings are valuable for a better understanding of the antiviral mechanism of B. mori underlying the interaction between the silkworm and BmNPV.


Assuntos
Bombyx , Imunidade Inata , Proteínas de Insetos/metabolismo , Nucleopoliedrovírus , Animais , Bombyx/imunologia , Bombyx/metabolismo , Bombyx/virologia , Sistema Digestório/metabolismo , Corpo Adiposo/metabolismo , Hemolinfa/metabolismo , Interações entre Hospedeiro e Microrganismos , Metaboloma/imunologia , Metabolômica/métodos , Nucleopoliedrovírus/imunologia
2.
Arch Insect Biochem Physiol ; 108(2): e21838, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34350621

RESUMO

Silkworm is not only an ideal insect model with a biological significance, but it is also crucially important in sericulture and bioreactors. Bombyx mori nucleopolyhedrovirus (BmNPV) is a principal pathogen of silkworm. However, the molecular mechanism underlying BmNPV invasion is still unclear. Based on our previous acetylome research findings of B. mori after BmNPV infection, here, we focused on silkworm alteration/deficiency in activation-3 (BmAda3). The acetylation of K124 and K128 were significantly reduced (0.66-fold) upon the virus challenge. Due to the interaction between Ada3 and P53, acetylation-mimic K124Q/K128Q and deacetylation-mimic K124R/K128R mutants of BmAda3 were constructed to explore the roles exerted by the acetylation modification of BmAda3 on P53. Yeast two-hybrid and IP results revealed that both BmAda3 and its deacetylation mutants (K124R/K128R) interacted with P53. Interestingly, we found that the deacetylation mutants (K124R/K128R) of BmAda3 significantly promoted the stability of P53. Since P53 is a proapoptotic factor, cell apoptosis was detected. We established that the deacetylation of BmAda3 at K124/K128 facilitated cellular apoptosis during BmNPV infection. Finally, viral proliferation was analyzed, and the results indicated that virus generation was reduced by K124/K128 deacetylation. Our report, based on the deacetylation of two lysine sites 124/128 of BmAda3, shows possible regulatory pathways of BmNPV proliferation and provides novel insights into the development of antiviral agents.


Assuntos
Apoptose , Bombyx/virologia , Histona Acetiltransferases , Nucleopoliedrovírus/patogenicidade , Proteína Supressora de Tumor p53/metabolismo , Animais , Bombyx/genética , Bombyx/metabolismo , Genes de Insetos , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Interações Hospedeiro-Patógeno , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Mutação
3.
Arch Insect Biochem Physiol ; 108(2): e21839, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34427962

RESUMO

Flavonoids are secondary metabolites that help plants resist insect attack. It can resist insect attack by inhibiting insect immune defense, and pathogens can also inhibit insect immune defense. It is speculated that the combination of flavonoids and pathogens may inhibit the immune defense and have stronger toxicity to silkworm. In this study, the combined treatment of quercetin with Bombyx mori nuclear polyhedrosis virus (BmNPV) had significant negative effects on the growth and survival of silkworm compared with BmNPV group. The detoxifying enzyme activity of BmNPV group was significantly increased at 96 h, while the activity of the combined treatment group was significantly decreased with the increase of quercetin exposure time (72 or 96 h). The activity of antioxidant enzymes also showed a similar trend, that was, the activity of antioxidant enzymes in the combined treatment group also decreased significantly with the increase of quercetin exposure time, which led to the increase of reactive oxygen species content. The silkworm cells would produce lipid peroxidation, malondialdehyde content was significantly increased, so that the expression of immune-related genes (the antimicrobial peptide, Toll pathway, IMD pathway, JAK-STAT pathway, and melanin genes) were decreased, leading to the damage of the immune system of silkworm. These results indicated that quercetin combined with BmNPV could inhibit the activities of protective enzymes and lead to oxidative damage to silkworm. It can also affect the immune response of the silkworm, and thus resulting in abnormal growth. This study provides the novel conclusion that quercetin accumulation will increase the susceptibility of silkworm to pathogens.


Assuntos
Bombyx , Quercetina/farmacologia , Animais , Antioxidantes/metabolismo , Bombyx/efeitos dos fármacos , Bombyx/crescimento & desenvolvimento , Bombyx/imunologia , Bombyx/virologia , Imunidade/efeitos dos fármacos , Desentoxicação Metabólica Fase I/imunologia , Nucleopoliedrovírus/imunologia , Espécies Reativas de Oxigênio/metabolismo
4.
Arch Insect Biochem Physiol ; 108(1): e21764, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34272769

RESUMO

Melanization is mediated by the prophenoloxidase (proPO) activation cascade and plays an important role in the arthropods immune system. Previously, we found that the hemolymph of the p50 strain does not perform melanization after infection with Autographa californica multiple nucleopolyhedrovirus (AcMNPV). However, this mechanism is still unclear. In this study, the underlying mechanism of the inhibition of hemolymph melanization was investigated by analysing the AcMNPV-susceptible or -resistant silkworm strains after inoculation with AcMNPV. The results showed that the level of hemolymph melanization was higher in resistant strain C108 than in susceptible strain p50 at the late stage (72 to 120 h postinoculation). The PO activity decreased significantly at the late stage of infection (72 to 120 hpi), and the expression of BmPPO1 and BmPPO2 was downregulated in p50. However, the PO activity increased in the resistant strain C108, while the expression level of BmPPO1 and BmPPO2 displayed no significant changes. The expression of the BmPPAE gene was upregulated in two strains during viral infection. In addition, the hemolymph melanization can weaken the viral activity in vitro. Our results suggested that the silkworm hemolymph melanization response is related to defence against the AcMNPV infection.


Assuntos
Bombyx , Imunidade , Melaninas/metabolismo , Nucleopoliedrovírus/imunologia , Animais , Bombyx/imunologia , Bombyx/virologia , Hemolinfa/metabolismo , Monofenol Mono-Oxigenase/metabolismo , Viroses/veterinária
5.
Int J Mol Sci ; 22(14)2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34299043

RESUMO

Bombyx mori nucleopolyhedrovirus (BmNPV) is a pathogen that causes great economic losses in sericulture. Many genes play a role in viral infection of silkworms, but silkworm metabolism in response to BmNPV infection is unknown. We studied BmE cells infected with BmNPV. We performed liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS)-based non-targeted metabolomics analysis of the cytosolic extract and identified 36, 76, 138, 101, 189, and 166 different molecules at 3, 6, 12, 24, 48, and 72 h post BmNPV infection (hpi) compared with 0 hpi. Compounds representing different areas of metabolism were increased in cells post BmNPV infection. These areas included purine metabolism, aminoacyl-tRNA biosynthesis, and ABC transporters. Glycerophosphocholine (GPC), 2-hydroxyadenine (2-OH-Ade), gamma-glutamylcysteine (γ-Glu-Cys), hydroxytolbutamide, and 5-pyridoxolactone glycerophosphocholine were continuously upregulated in BmE cells post BmNPV infection by heat map analysis. Only 5-pyridoxolactone was found to strongly inhibit the proliferation of BmNPV when it was used to treat BmE cells. Fewer infected cells were detected and the level of BmNPV DNA decreased with increasing 5-pyridoxolactone in a dose-dependent manner. The expression of BmNPV genes ie1, helicase, GP64, and VP39 in BmE cells treated with 5-pyridoxolactone were strongly inhibited in the BmNPV infection stage. This suggested that 5-pyridoxolactone may suppress the entry of BmNPV. The data in this study characterize the metabolism changes in BmNPV-infected cells. Further analysis of 5-pyridoxolactone, which is a robust antiviral molecule, may increase our understanding of antiviral immunity.


Assuntos
4-Butirolactona/análogos & derivados , Antivirais/farmacologia , Bombyx/efeitos dos fármacos , Bombyx/metabolismo , Lactonas/farmacologia , Metaboloma , Nucleopoliedrovírus/efeitos dos fármacos , Piridinas/farmacologia , 4-Butirolactona/farmacologia , Animais , Bombyx/virologia
6.
Viruses ; 13(5)2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066413

RESUMO

Viruses rely on host cell metabolism to provide the necessary energy and biosynthetic precursors for successful viral replication. Infection of the silkworm, Bombyx mori, by Bombyx mori nucleopolyhedrovirus (BmNPV), has been studied extensively in the past to unravel interactions between baculoviruses and their lepidopteran hosts. To understand the interaction between the host metabolic responses and BmNPV infection, we analyzed global metabolic changes associated with BmNPV infection in silkworm hemolymph. Our metabolic profiling data suggests that amino acid metabolism is strikingly altered during a time course of BmNPV infection. Amino acid consumption is increased during BmNPV infection at 24 h post infection (hpi), but their abundance recovered at 72 hpi. Central carbon metabolism, on the other hand, particularly glycolysis and glutaminolysis, did not show obvious changes during BmNPV infection. Pharmacologically inhibiting the glycolytic pathway and glutaminolysis also failed to reduce BmNPV replication, revealing that glycolysis and glutaminolysis are not essential during BmNPV infection. This study reveals a unique amino acid utilization process that is implemented during BmNPV infection. Our metabolomic analysis of BmNPV-infected silkworm provides insights as to how baculoviruses induce alterations in host metabolism during systemic infection.


Assuntos
Aminoácidos/metabolismo , Baculoviridae/fisiologia , Bombyx/metabolismo , Bombyx/virologia , Hemolinfa/metabolismo , Hemolinfa/virologia , Metabolômica , Animais , Bombyx/genética , Cromatografia Líquida , Biologia Computacional/métodos , Metabolismo Energético , Perfilação da Expressão Gênica , Glicólise , Interações Hospedeiro-Patógeno , Metaboloma , Metabolômica/métodos , Espectrometria de Massas em Tandem
7.
Viruses ; 13(5)2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068017

RESUMO

The mulberry silkworm, Bombyx mori (L.), is a model organism of lepidopteran insects with high economic importance. The viral diseases of the silkworm caused by Bombyx mori nucleopolyhedrovirus (BmNPV) and Bombyx mori bidensovirus (BmBDV) inflict huge economic losses and significantly impact the sericulture industry of India and other countries. To understand the distribution of Indian isolates of the BmNPV and to investigate their genetic composition, an in-depth population structure analysis was conducted using comprehensive and newly developed genomic analysis methods. The seven new Indian BmNPV isolates from Anantapur, Dehradun, Ghumarwin, Jammu, Kashmir, Mysore and Salem grouped in the BmNPV clade, and are most closely related to Autographa californica multiple nucleopolyhedrovirus and Rachiplusia ou multiple nucleopolyhedrovirus on the basis of gene sequencing and phylogenetic analyses of the partial polh, lef-8 and lef-9 gene fragments. The whole genome sequencing of three Indian BmNPV isolates from Mysore (-My), Jammu (-Ja) and Dehradun (-De) was conducted, and intra-isolate genetic variability was analyzed on the basis of variable SNP positions and the frequencies of alternative nucleotides. The results revealed that the BmNPV-De and BmNPV-Ja isolates are highly similar in their genotypic composition, whereas the population structure of BmNPV-My appeared rather pure and homogenous, with almost no or few genetic variations. The BmNPV-De and BmNPV-Ja samples further contained a significant amount of BmBDV belonging to the Bidnaviridae family. We elucidated the genotype composition within Indian BmNPV and BmBDV isolates, and the results presented have broad implications for our understanding of the genetic diversity and evolution of BmNPV and co-occurring BmBDV isolates.


Assuntos
Bombyx/virologia , Genótipo , Vírus de Insetos/genética , Nucleopoliedrovírus/genética , Animais , DNA Viral , Genes Virais , Genoma Viral , Índia , Vírus de Insetos/classificação , Vírus de Insetos/isolamento & purificação , Nucleopoliedrovírus/classificação , Nucleopoliedrovírus/isolamento & purificação , Fases de Leitura Aberta , Filogenia , Filogeografia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
8.
Virus Genes ; 57(5): 459-463, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34185196

RESUMO

Baculovirus infection modulates the chromatin states and gene expression of host insect cells. Here we performed chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) of H3 trimethylated at Lys4 (H3K4me3) histone modification in Bombyx mori nucleopolyhedrovirus-infected Bombyx mori cells. The ChIP-seq data revealed the changes of the genome-wide distribution and accumulation of euchromatic histone marks in host insect cells during the progression of baculovirus infection.


Assuntos
Bombyx/genética , Cromatina/genética , Histonas/genética , Nucleopoliedrovírus/genética , Animais , Baculoviridae/genética , Baculoviridae/patogenicidade , Bombyx/virologia , Cromatina/virologia , Regulação da Expressão Gênica/genética , Sequenciamento de Nucleotídeos em Larga Escala , Código das Histonas/genética , Nucleopoliedrovírus/patogenicidade , Processamento de Proteína Pós-Traducional/genética
9.
Arch Insect Biochem Physiol ; 107(3): e21793, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33949719

RESUMO

Apoptosis, as one kind of innate immune system, is involved in host response against pathogens innovation. Caspases play a vital role in the execution stage of host cell apoptosis. It has been reported that Bmcaspase-1 (Bmcas-1) has a close relationship with Bombyx mori nucleopolyhedrovirus (BmNPV) infection for its differentially expressed patterns after viral infection. However, its underlying response mechanism is still unclear. The significant differential expression of Bmcas-1 in different tissues of differentially resistant strains revealed its vital role in BmNPV infection. To further validate its role in BmNPV infection, budded virus (BV)-eGFP was analyzed after knockdown and overexpression of Bmcas-1 by small interfering RNA and the pIZT-mCherry vector, respectively. The reproduction of BV-eGFP obviously increased at 72 h after knockdown of Bmcas-1, and decreased after overexpression in BmN cells. Moreover, the conserved functional domain of Cas-1 among different species and the closed evolutionary relationship of Cas-1 in Lepidoptera hinted that Bmcas-1 might be associated with apoptosis, and this was also validated by the apoptosis inducer, Silvestrol, and the inhibitor, Z-DEVD-FMK. Therefore, Bmcas-1 plays an essential antiviral role by activating apoptosis, and this result lays a fundament for clarifying the molecular mechanism of silkworm in response against BmNPV infection and breeding of resistant strains.


Assuntos
Apoptose , Bombyx/virologia , Caspase 1/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Nucleopoliedrovírus/imunologia , Animais , Bombyx/enzimologia , Bombyx/imunologia , Caspase 1/imunologia , Proteínas de Fluorescência Verde
10.
Front Immunol ; 12: 645359, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33995363

RESUMO

A wide range of hemocyte types exist in insects but a full definition of the different subclasses is not yet established. The current knowledge of the classification of silkworm hemocytes mainly comes from morphology rather than specific markers, so our understanding of the detailed classification, hemocyte lineage and functions of silkworm hemocytes is very incomplete. Bombyx mori nucleopolyhedrovirus (BmNPV) is a representative member of the baculoviruses and a major pathogen that specifically infects silkworms (Bombyx mori) and causes serious losses in sericulture industry. Here, we performed single-cell RNA sequencing (scRNA-seq) of hemocytes in BmNPV and mock-infected larvae to comprehensively identify silkworm hemocyte subsets and determined specific molecular and cellular characteristics in each hemocyte subset before and after viral infectmadion. A total of 20 cell clusters and their potential marker genes were identified in silkworm hemocytes. All of the hemocyte clusters were infected by BmNPV at 3 days after inoculation. Interestingly, BmNPV infection can cause great changes in the distribution of hemocyte types. The cells appearing in the infection group mainly belong to prohemocytes (PR), while plasmatocytes (PL) and granulocytes (GR) are very much reduced. Furthermore, we found that BmNPV infection suppresses the RNA interference (RNAi) and immune response in the major hemocyte types. In summary, our results revealed the diversity of silkworm hemocytes and provided a rich resource of gene expression profiles for a systems-level understanding of their functions in the uninfected condition and as a response to BmNPV.


Assuntos
Bombyx , Hemócitos , Nucleopoliedrovírus/imunologia , RNA-Seq , Análise de Célula Única , Animais , Bombyx/imunologia , Bombyx/virologia , Hemócitos/imunologia , Hemócitos/virologia , Larva/imunologia , Larva/virologia
11.
Front Immunol ; 12: 639092, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33643323

RESUMO

The lepidopteran model silkworm, Bombyx mori, is an important economic insect. Viruses cause serious economic losses in sericulture; thus, the economic importance of these viruses heightens the need to understand the antiviral pathways of silkworm to develop antiviral strategies. Insect innate immunity pathways play a critical role in the outcome of infection. The RNA interference (RNAi), NF-kB-mediated, immune deficiency (Imd), and stimulator of interferon gene (STING) pathways, and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway are the major antiviral defense mechanisms, and these have been shown to play important roles in the antiviral immunity of silkworms. In contrast, viruses can modulate the prophenol oxidase (PPO), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), and the extracellular signal-regulated kinase (ERK) signaling pathways of the host to elevate their proliferation in silkworms. In this review, we present an overview of the current understanding of the main immune pathways in response to viruses and the signaling pathways modulated by viruses in silkworms. Elucidation of these pathways involved in the antiviral mechanism of silkworms furnishes a theoretical basis for the enhancement of virus resistance in economic insects, such as upregulating antiviral immune pathways through transgenic overexpression, RNAi of virus genes, and targeting these virus-modulated pathways by gene editing or inhibitors.


Assuntos
Bombyx/imunologia , Bombyx/virologia , Interações Hospedeiro-Parasita/imunologia , Animais
12.
Int J Biol Macromol ; 175: 372-378, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33549665

RESUMO

The viruses utilize multiple cellular proteins to facilitate their proliferation. The Heat Shock Protein (HSP), the highly conserved protein in eukaryotes and prokaryotes, plays a critical role in facilitating viral proliferation. However, less is known about the role of the HSPs in the life cycles of the Baculoviruses. We constructed recombinant Bombyx mori nucleopolyhedrovirus and discovered the Heat Shock Protein 75 (TRAP1) in the B. mori ovary (BmN) cells by the co-immunoprecipitation experiment using the GP64 (glycoprotein 64) as the bait protein. Tissue expression profile analysis of B. mori indicated that the TRAP1 gene has higher expression levels in the ovary, midgut, and hemolymph. Down-regulation of TRAP1 via RNA interference (RNAi) and geldanamycin (GA, a TRAP1 inhibitor) treatment can reduce the expression level of the major capsid protein VP39 (viral protein 39) of BmNPV. In contrast, the up-regulation of TRAP1 via overexpression can increase the expression level of the VP39. These results indicated that the TRAP1 of B. mori could facilitate the proliferation of the BmNPV. This study provided new insights into the function of TRAP1, and the basic mechanisms of the baculoviruses life cycle for disease prevention.


Assuntos
Bombyx/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Nucleopoliedrovírus/metabolismo , Animais , Bombyx/virologia , Linhagem Celular , Proliferação de Células , Proteínas de Choque Térmico/metabolismo , Hemolinfa/metabolismo , Proteínas de Insetos/genética , Larva/genética , Nucleopoliedrovírus/crescimento & desenvolvimento , Interferência de RNA/fisiologia , Proteínas Virais/genética , Replicação Viral
13.
Arch Insect Biochem Physiol ; 106(3): 1-12, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33619747

RESUMO

Bombyx mori cypovirus (BmCPV) is one of the most important pathogens causing severe disease to silkworm. Emerging evidence indicates that long noncoding RNAs (lncRNAs) play importantly regulatory roles in virus infection and host immune response. To better understand the interaction between silkworm, Bombyx mori and BmCPV, we performed a comparative transcriptome analysis on lncRNAs and mRNAs between the virus-infected and noninfected silkworm larvae midgut at two time points postinoculation. A total of 16,753 genes and 1845 candidate lncRNAs were identified, among which 356 messenger RNA (mRNAs) and 41 lncRNAs were differentially expressed (DE). Target gene prediction revealed that most of DEmRNAs (123) were coexpressed with 28 DElncRNAs, suggesting that the expression of mRNA is mainly affected through trans- regulation by BmCPV-induced lncRNAs, and a regulatory network of DElncRNAs and DEmRNAs was then constructed. According to the network, many genes involved in apoptosis, autophagy, and antiviral response, such as ATG3, PDCD6, IBP2, and MFB1, could be targeted by different DElncRNAs, implying the essential roles of these genes and lncRNAs in BmCPV infection. In all, our studies revealed for the first time the alteration of lncRNA expression in BmCPV-infected larvae and its potential influence on BmCPV replication, providing a new perspective for host-cypovirus interaction studies.


Assuntos
Bombyx , RNA Longo não Codificante , Viroses , Animais , Bombyx/genética , Bombyx/imunologia , Bombyx/metabolismo , Bombyx/virologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Genes de Insetos , Interações entre Hospedeiro e Microrganismos , Imunidade , Larva/genética , Larva/imunologia , Larva/metabolismo , RNA Longo não Codificante/isolamento & purificação , RNA Longo não Codificante/metabolismo , RNA Mensageiro/metabolismo , Reoviridae , Viroses/imunologia , Viroses/metabolismo
14.
Front Immunol ; 12: 628151, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33633750

RESUMO

Insects are the largest group of animals. Nearly all organisms, including insects, have viral pathogens. An important domesticated economic insect is the silkworm moth Bombyx mori. B. mori nucleopolyhedrovirus (BmNPV) is a typical baculovirus and a primary silkworm pathogen. It causes major economic losses in sericulture. Baculoviruses are used in biological pest control and as a bioreactor. Silkworm and baculovirus comprise a well-established model of insect-virus interactions. Several recent studies have focused on this model and provided novel insights into viral infections and host defense. Here, we focus on baculovirus invasion, silkworm immune response, baculovirus evasion of host immunity, and enhancement of antiviral efficacy. We also discuss major issues remaining and future directions of research on silkworm antiviral immunity. Elucidation of the interaction between silkworm and baculovirus furnishes a theoretical basis for targeted pest control, enhanced pathogen resistance in economically important insects, and bioreactor improvement.


Assuntos
Bombyx/virologia , Evasão da Resposta Imune , Nucleopoliedrovírus/patogenicidade , Animais , Bombyx/genética , Bombyx/imunologia , Nucleopoliedrovírus/genética , Nucleopoliedrovírus/imunologia , Controle Biológico de Vetores
15.
Arch Insect Biochem Physiol ; 106(2): e21762, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33415772

RESUMO

Bombyx mori nucleopolyhedrovirus (BmNPV) is one of primary silkworm pathogens and causes a serious damage of cocoon losses every year. Recent years, many works have been done to clarify the silkworm anti-BmNPV mechanism, and a significant progress has been made in screening and studying of genes and proteins related to BmNPV infection, but several of them lacked the proofs in vivo. In this study, to further validate the function of seven newly reported genes in vivo, including BmAtlatin-n, Bmferritin-heavy chain (BmFerHCH), Bmthymosin (BmTHY), Bmseroin1, Bmseroin2, Bmnuclear hormone receptors 96 (BmNHR96), and BmE3 ubiquitin-protein ligase SINA-like 10 (BmSINAL10), the response of them in the midgut, fat body, and hemolymph of differentially resistant strains (resistant strain YeA and susceptible strain YeB) at 48 h following BmNPV infection were analyzed. The results showed that the relative stable or upregulated expression level of BmAtlatin-n, BmTHY, Bmseroin1, and Bmseroin2 in YeA resistant strain following BmNPV infection further indicated their antiviral role in vivo, compared with susceptible YeB strain. Moreover, the significant downregulation of BmFerHCH, BmNHR96, and BmSINAL10 in both strains following BmNPV infection revealed their role in benefiting virus infection, as well as the upregulation of BmFerHCH in YeB midgut and BmSINAL10 in YeB hemolymph. These data could be used to complementary the proofs of the function of these genes in response to BmNPV infection.


Assuntos
Bombyx/genética , Bombyx/virologia , Genes de Insetos , Interações Hospedeiro-Patógeno , Nucleopoliedrovírus/fisiologia , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/metabolismo , Corpo Adiposo/metabolismo , Trato Gastrointestinal/metabolismo , Hemolinfa/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/virologia
16.
Int J Biol Macromol ; 166: 529-537, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33130268

RESUMO

Apoptosis is a cellular defense mechanism used for the elimination of host cells infected by viruses. Viruses have evolved corresponding inhibitors of apoptosis genes to promote their replication. Anti-apoptosis-related genes, involved in baculovirus proliferation, have been proposed but it is unclear whether these genes can be manipulated in gene therapy. We constructed a transgenic silkworm, using the CRISPR/Cas9 system to knock out the BmNPV inhibitor of apoptosis 2 (iap2). The sequencing results showed that all the sequences could edit the target site of BmNPV iap2 gene. There were no differences in economic traits and growth tests between the BmNPV iap2 knockout strain transgenic silkworm lines and the control groups. However, the mortality rate was significantly reduced, the median lethal dose (LD50) was about 100 times higher than the control group, and the onset time was prolonged by 1-2 days after knocking out BmNPV iap2. In addition, the expression levels of apoptotic-related genes Bmiap2, BmICE and BmDreed were significantly affected and the activity of caspase 9 was increased after BmNPV iap2 being edited in transgenic silkworm. These results demonstrated that gene editing BmNPV iap2 could significantly inhibit BmNPV replication and proliferation. This approach provides a new strategy for antiviral research.


Assuntos
Antivirais/metabolismo , Bombyx/virologia , Edição de Genes , Nucleopoliedrovírus/genética , Proteínas Virais/genética , Animais , Animais Geneticamente Modificados , Apoptose/genética , Sequência de Bases , Interações Hospedeiro-Patógeno/genética , Nucleopoliedrovírus/fisiologia , Replicação Viral
17.
Insect Sci ; 28(3): 662-679, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32367653

RESUMO

Bombyx mori nucleopolyhedrovirus (BmNPV) is a DNA virus that causes huge losses to the silkworm industry but the piRNA responses during BmNPV infection in the silkworm remain uninvestigated. Here, silkworm piRNA profiles of uninfected and BmNPV-infected fat body and midgut were determined by high-through sequencing in the early stages of BmNPV infection. A total of 2675 and 3396 genome-derived piRNAs were identified from fat body and midgut, respectively. These genome-derived piRNAs mainly originated from unannotated instead of transposon regions in the silkworm genome. In total, 572 piRNAs were associated with 280 putative target genes in fat body and 805 piRNAs with 380 target genes in midgut. Compared to uninfected tissues, 322 and 129 piRNAs were significantly upregulated in BmNPV-infected fat body and midgut, respectively. In addition, 276 and 117 piRNAs were significantly downregulated. Moreover, differentially expressed (DE) piRNAs during BmNPV infection differed significantly between fat body and midgut. Putative DE piRNA-targeted genes were associated with "response to stimulus" and "environmental information processing" in fat body after infection with BmNPV, which may indicate an active piRNA response to BmNPV infection in fat body. This study may lay the foundation for future research of the potential roles of the piRNA pathway and specific piRNAs in BmNPV pathogenesis.


Assuntos
Bombyx , Corpo Adiposo/metabolismo , Trato Gastrointestinal/metabolismo , Nucleopoliedrovírus/patogenicidade , RNA Interferente Pequeno/metabolismo , Animais , Bombyx/genética , Bombyx/metabolismo , Bombyx/virologia , Genoma de Inseto , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Patógeno
18.
Arch Insect Biochem Physiol ; 106(2): e21761, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33225529

RESUMO

Bombyx mori latent virus (BmLV) is a positive, single-stranded insect RNA virus closely related to plant maculaviruses. BmLV was first isolated from Bombyx mori ovary-derived cell line BmN-4, and this virus has already infected most B. mori-derived cultured cell lines. We previously reported that small interfering RNA (siRNA) and PIWI-interacting RNA (piRNA) pathways function cooperatively to maintain the amount of BmLV RNA for normal BmN-4 cell growth. On the other hand, BmLV does not propagate in B. mori larvae. Here we conducted BmLV injection into the larval body cavities of B. mori, and examined BmLV accumulation in larval ovaries where siRNA and piRNA pathways are both active, to investigate whether this in vivo resistance is governed by small RNA pathways. Expression levels of RNA-dependent RNA polymerase, coat protein, and p15 genes in BmLV-injected larval ovaries were extremely low compared with those in B. mori cultured cells, indicating that B. mori larval ovaries are more resistant to BmLV than B. mori cultured cells. We also sequenced small RNAs prepared from BmLV-injected larval ovaries and mapped them onto the BmLV genome. Although their amounts were very small, we were able to detect BmLV-derived small RNAs in the ovaries. According to their length distribution and nucleotide bias, they were likely to be siRNAs and piRNAs. These results suggest that B. mori ovaries can potentially produce small RNAs against BmLV, but the resistance of larval ovaries against BmLV is not dependent on RNA silencing pathways.


Assuntos
Bombyx/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , RNA Interferente Pequeno/metabolismo , Tymoviridae/fisiologia , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/virologia , Feminino , Larva/crescimento & desenvolvimento , Larva/imunologia , Larva/virologia , Ovário/imunologia , Ovário/metabolismo
19.
Parasitology ; 148(1): 105-109, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33054893

RESUMO

Many parasites manipulate host behaviour to enhance their transmission. Baculoviruses induce enhanced locomotory activity (ELA) combined with subsequent climbing behaviour in lepidopteran larvae, which facilitates viral dispersal. However, the mechanisms underlying host manipulation system are largely unknown. Previously, larval locomotion during ELA was summarized as the distance travelled for a few minutes at several time points, which are unlikely to characterize ELA precisely, as ELA typically persists for several hours. In this study, we modified a recently developed method using time-lapse recording to characterize locomotion of Bombyx mori larvae infected with Bombyx mori nucleopolyhedrovirus (BmNPV) for 24 h at 3 s resolution. Our data showed that the locomotion of the mock-infected larvae was restricted to a small area, whereas the BmNPV-infected larvae exhibited a large locomotory area. These results indicate that BmNPV dysregulates the locomotory pattern of host larvae. Furthermore, both the mock- and BmNPV-infected larvae showed periodic cycles of movement and stationary behavior with a similar frequency, suggesting the physiological mechanisms that induce locomotion are unaffected by BmNPV infection. In contrast, the BmNPV-infected larvae exhibited fast and long-lasting locomotion compared with mock-infected larvae, which indicates that locomotory speed and duration are manipulated by BmNPV.


Assuntos
Bombyx/virologia , Locomoção , Nucleopoliedrovírus/patogenicidade , Animais , Baculoviridae/patogenicidade , Comportamento , Bombyx/fisiologia , Interações entre Hospedeiro e Microrganismos , Larva/fisiologia , Larva/virologia , Imagem com Lapso de Tempo/métodos , Viroses
20.
Virus Res ; 292: 198261, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33316354

RESUMO

Bombyx mori cypovirus 1 (BmCPV1) is a member of the Reoviridae family which is characterized by its single-layered capsid. Similar with other turreted viruses in the Reoviridae, transcription of BmCPV1 occurs inside the capsid, and the nascent mRNA is released to the turret which consists of five turret proteins (TPs) and located at the 5-fold axis of the outer capsid, then the capping enzyme TP will guanylate and methylate the nascent viral mRNA to produce a matured mRNA. However, during these processes, how the BmCPV1 draws other cellular proteins to facilitate its replication is still lesser-known. Here we used an ELISA to investigate the interaction between ALP and BmCPV1. A co-immunoprecipitation technique was employed to detect the interaction of ALP with the Methylase domain of TP. We further studied whether ALP affects the replication of BmCPV1 inside the cell, results show that reducing the expression of ALP through RNAi reduced the transcription level of the BmCPV1 VP1 gene, which was increased by overexpression of ALP. In summary, our data demonstrate an interaction between ALP and BmCPV1 and that ALP promoted the replication of BmCPV1, and support our hypothesis of the ALP is an RTPase to facilitate the capping process of BmCPV1.


Assuntos
Fosfatase Alcalina/metabolismo , Bombyx/enzimologia , Proteínas do Capsídeo/metabolismo , Proteínas de Insetos/metabolismo , Reoviridae/metabolismo , Replicação Viral , Fosfatase Alcalina/genética , Animais , Bombyx/genética , Bombyx/virologia , Proteínas do Capsídeo/genética , Interações Hospedeiro-Patógeno , Proteínas de Insetos/genética , Ligação Proteica , Reoviridae/genética
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