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1.
Insect Mol Biol ; 29(1): 104-111, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31390480

RESUMO

Acetylation is an important, reversible posttranslational modification to a protein. In a previous study, we found that there were a large number of acetylated sites in various nutrient storage proteins of the silkworm haemolymph. In this study, we confirmed that acetylation can affect the stability of nutrient storage protein Bombyx mori apolipophorin-III (BmApoLp-III). First, the expression of BmApoLp-III could be upregulated when BmN cells were treated with the deacetylase inhibitor panobinostat (LBH589); similarly, the expression was downregulated when the cells were treated with the acetylase inhibitor C646. Furthermore, the increase in acetylation by LBH589 could inhibit the degradation and improve the accumulation of BmApoLp-III in BmN cells treated with cycloheximide and MG132 respectively. Moreover, we found that an increase in acetylation could decrease the ubiquitination of BmApoLp-III and vice versa; therefore, we predicted that acetylation could improve the stability of BmApoLp-III by competing for ubiquitination and inhibiting the protein degradation pathway mediated by ubiquitin. Additionally, BmApoLp-III had an antiapoptosis function that increased after LBH589 treatment, which might have been due to the improved protein stability after acetylation. These results have laid the foundation for further study on the mechanism of acetylation in regulating the storage and utilization of silkworm nutrition.


Assuntos
Apolipoproteínas/química , Bombyx/química , Proteínas de Insetos/química , Estabilidade Proteica/efeitos dos fármacos , Acetilação , Animais , Apolipoproteínas/metabolismo , Benzoatos/farmacologia , Bombyx/efeitos dos fármacos , Linhagem Celular , Cicloeximida/farmacologia , Proteínas de Insetos/metabolismo , Leupeptinas/farmacologia , Panobinostat/farmacologia , Pirazóis/farmacologia
2.
Chemosphere ; 239: 124697, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499307

RESUMO

This study investigates the effects of the insect growth regulator Novaluron on the silk gland (SG) and silk cocoon production in a nontarget insect, the silkworm Bombyx mori, which is a model research insect among Lepidoptera and of great economic importance for the commercial production of silk threads. Larvae were segregated into experimental groups: the control group (CG) and the treatment group (TG), which was exposed to a Novaluron concentration of 0.15 mL/L. Following exposure, we analyzed the cytotoxic effects on the epithelial cells of the anterior, middle and posterior regions of the SG of B. mori larvae in the 3rd, 4th, and 5th instars, as well as the quality of the cocoons from larvae in the 5th instar. Cytotoxic effects were observed in the TG, such as the dilation of cells, emission of cytoplasmic protrusions, extreme rarefaction of the cytoplasm and nuclei, dilation of the endoplasmic reticulum, intracellular and intercellular spaces, spacing between the epithelial cells and the basal lamina and detachment of some cells towards the lumen of the SG, and decreased protein in the lumen, with faults in its composition. In addition, we verified ultrastructural changes in the production of fibers and silk cocoons, including a reduction in the weight of the cocoons constructed by both males and females in the TG and the construction of defective cocoons. Novaluron exposure impairs the SG and may affect the physiological functions of this organ; additionally, it compromises the quality of silk cocoons, potentially causing serious damage to sericulture.


Assuntos
Bombyx/efeitos dos fármacos , Larva/efeitos dos fármacos , Compostos de Fenilureia/farmacologia , Seda/efeitos dos fármacos , Animais , Células Epiteliais/efeitos dos fármacos , Inseticidas/farmacologia , Lepidópteros , Seda/biossíntese
3.
Pestic Biochem Physiol ; 160: 154-162, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31519250

RESUMO

Sanguinarine (Sang) is a natural alkaloid and distributed in several plants of Papaveraceae. The antitumor, antioxidant, antimicrobial and anti-inflammatory effects of Sang were extensively reported, but its speciality and mechanism against Lepidoptera insects were still unknown. In this study, detailed toxicological parameters of Sang against silkworms, Bombyx mori (B. mori), were determined by a toxicological test. Then, a nuclear magnetic resonance-based (NMR) metabolomics method was adopted to analyze the changes in hemolymph metabolites of silkworms after feeding Sang. The growth of fourth-instar larvae was significantly ceased by the oral administration of 0.05-0.3% Sang and vast deaths appeared in 0.3% Sang group on Day 4 and Day 5. The quantitative analysis of metabolites indicated that trehalose and citrate levels in hemolymph were increased after 24 h of feeding 0.3% Sang, whereas the concentrations of pyruvate, succinate, malate and fumarate were decreased. In addition, the enzymatic determination and reverse transcription quantitative PCR (RT-qPCR) showed that the trehalase (THL) activity and the transcriptional level of one gene coding THL were uniformly weakened by 0.3% Sang. One of the important mechanisms of Sang against silkworms might be interpreted as follows. Sang impaired trehalose hydrolysis, reduced THL activity and transcription, and led to the inhibition of energy metabolism, consequent antigrowth and high lethality in larvae of B. mori. Our findings offered new insights into the insecticidal effect of Sang from the perspective of energy metabolism and provided the basis for the application of Sang in the control of Lepidoptera pests.


Assuntos
Benzofenantridinas/toxicidade , Bombyx/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Isoquinolinas/toxicidade , Larva/efeitos dos fármacos , Animais , Bombyx/crescimento & desenvolvimento , Hemolinfa/metabolismo , Inseticidas/farmacologia , Metabolômica
4.
Ecotoxicology ; 28(8): 903-912, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392633

RESUMO

Silkworm (Bombyx mori) is an economic insect of the Lepidoptera. Chlorantraniliprole (CAP) exposure results in reduced growth and development of B. mori and failure in cocooning, seriously affecting the development of sericulture. To study the mechanisms underlying the damage to silkworm caused by sublethal doses of CAP, we examined the oxidative damage, the activities of digestive enzymes in midgut, and the expressions of midgut-related genes at the mRNA level. We found that CAP exposure inhibited the growth of silkworm, decreased the body mass and caused the accumulation of reactive oxygen species (ROS) [the levels of O2-, H2O2 and lipid peroxidation (MDA) were increased by 1.62-, 1.87- and 1.46-fold, respectively]. Moreover, we also found that the midgut cells were disintegrated, microvilli disappeared, the stroma became thinner, and the chromatin of nucleus became aggregated after CAP exposure by the analysis of transmission electron microscopy (TEM). In addition, the activities of digestive enzymes were dysregulated in midgut (the activities of α-amylase and trypsin were decreased 0.69- and 0.20-fold, respectively). Furthermore, digital gene expression (DGE) profiling analysis revealed that the expressions of oxidative phosphorylation pathway and antioxidant defense system related genes in midgut were decreased, indicating that it was the oxidative damage in midgut caused by CAP that mainly affected the growth of silkworm, rather than the toxicological effects of CAP. Collectively, this study provided valuable insights into the toxic effects of CAP on insects.


Assuntos
Bombyx/efeitos dos fármacos , Inseticidas/toxicidade , ortoaminobenzoatos/toxicidade , Animais , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Bombyx/fisiologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/fisiologia , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Estresse Oxidativo/efeitos dos fármacos
5.
J Ethnopharmacol ; 245: 112155, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31449858

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Indian medicine has utilized Aeglemarmelos (L.) Corr. commonly called as bael in several indigenous systems against various diseases. Bioactive components isolated from various plant parts of A. marmelos were used in ethno-medicine. More precisely they are known for its antiviral property against various human and animal viruses. AIM OF THE STUDY: The study was conducted to investigate the antiviral activity of A.marmelos against Bombyx mori nucleopolyhedrovirus (BmNPV). MATERIALS AND METHODS: Among the various crude extracts tested, hexane extracts of leaves of A. marmelos with promising anti-BmNPV activity was subjected to bioactivity guided fractionation based on column chromatography. Out of 40 fractions obtained from the fractionation, fractions showing similar TLC profiles were pooled into 14 fractions. A fraction with potential activity was used to purify a molecule with anti-BmNPV activity. This molecule was characterized through structural and functional analyses. RESULTS: The functionally and structurally characterized molecule in the fraction with prospective anti-BmNPV activity revealed a single crystal compound 'seselin' (8, 8-dimethyl pyrido oxazine-2-one). CONCLUSION: It is therefore understood that this seselin compound could be used as a natural medicine for the management of NPV infection in the silkworm larvae under commercial conditions after suitable field evaluations.


Assuntos
Aegle , Antivirais/uso terapêutico , Bombyx/efeitos dos fármacos , Cumarínicos/uso terapêutico , Larva/efeitos dos fármacos , Animais , Antivirais/farmacologia , Bombyx/virologia , Cumarínicos/farmacologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/patologia , Hemócitos/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Larva/virologia , Simulação de Acoplamento Molecular , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Folhas de Planta
6.
Chemosphere ; 234: 338-345, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31228835

RESUMO

Silkworm (Bombyx mori) is one of the most important economic insects in the world, while pesticides impact its economic benefits. Tebuconazole is a fungicide that has been frequently detected in agriculture systems at concentrations that affect endocrine function in organisms. In the present study, silkworm larvae at different instar stages were exposed to tebuconazole, respectively. Cocoon weight, cocoon shell weight and cocoon shell rate were significantly decreased by 6.8%, 11.8% and 4.4% respectively, after exposure to 0.40 mg/L tebuconazole at 2nd -3rd instar stage. Vacuolization was found in the exposure silkworm under histopathological study at all stages exposures, indicating potential damage to silk gland. Downregulation of genes transcription (Fibh, Fibl, P25, Ser2, Ser3) involved with protein synthesis in the silk gland were further observed, and the results showed significant decreasing in mRNA expression among the tebuconazole treatments. Ecdysteroid levels in silkworm were changed with pronounced decreases after exposed to tebuconazole. In contrast, exposure to tebuconazole significantly increased juvenile hormone 1 concentrations and the maximum increasing fold of juvenile hormone 1 was up to 3.73 which was observed at stage I exposure. In addition, co-exposure to 2 and 10 mg/L forskolin able to mitigate tebuconazole-induced downregulate of mRNA expression of Sgf1 in the present study, indicating the potential mechanism of tebuconazole-induced chronic toxicity in silkworm may relative to PI3K/AKT/TORC1/Sgf1 pathway.


Assuntos
Bombyx/efeitos dos fármacos , Seda/genética , Triazóis/toxicidade , Animais , Regulação para Baixo , Ecdisteroides/metabolismo , Expressão Gênica/efeitos dos fármacos , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Biossíntese de Proteínas , Sesquiterpenos/metabolismo , Transativadores/metabolismo
7.
Environ Toxicol ; 34(9): 1043-1051, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31120183

RESUMO

Acetamiprid is widely used for agricultural pest control. However, it remains poorly understood whether the environmental residues of acetamiprid have the potential effects on economic insect. In this study, we evaluated the effects of acetamiprid on silkworm growth and development. The exposure to trace amounts of acetamiprid significantly decreased body weight, viability, and spinning ability. In addition, the activity of trypsin in the midgut was decreased after exposure. DGE and KEGG pathway enrichment analysis revealed that the significantly differentially expressed genes were mainly involved in nutrient metabolism, stress responses, and inflammation pathways. These results, in combination with hematoxylin-eosin staining and transmission electron microscopy, indicated that acetamiprid could cause oxidative damage to midgut, lead to inflammatory responses, and affect the activities of midgut digestive enzymes, thus resulting in abnormal growth and development. Our findings greatly contributed to the evaluation of the effects of acetamiprid residues on other nontarget beneficial insect.


Assuntos
Bombyx/efeitos dos fármacos , Larva/efeitos dos fármacos , Neonicotinoides/toxicidade , Resíduos de Praguicidas/toxicidade , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/metabolismo , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/ultraestrutura , Relação Dose-Resposta a Droga , Dose Letal Mediana , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Tripsina/metabolismo
8.
Molecules ; 24(7)2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30939726

RESUMO

Bombyx mori nucleopolyhedrovirus (BmNPV) is the most prevalent threat to silkworms. Hence, there is a need for antiviral agents in sericulture. The PI3K-Akt pathway is essential for the efficient replication of the baculovirus. In an attempt to screen antiviral drugs against BmNPV, we summarized the commercial compounds targeting PI3K-Akt and selected the following seven oral drugs for further analyses: afuresertib, AZD8835, AMG319, HS173, AS605240, GDC0941, and BEZ235. Cell viability assay revealed that the cytotoxicity of these drugs at 10 µM concentration was not strong. Viral fluorescence observation and qPCR analysis showed that these candidate drugs significantly inhibited BmNPV in BmE cells. Only AMG319 and AZD8835 inhibited viral proliferation in silkworm larvae. The mortality of AZD8835-treated silkworms was lower than that of the control silkworms. Western blotting showed that AMG319 and AZD8835 decreased p-Akt expression after BmNPV infection. These results suggest that AZD8835 has application potential in sericulture.


Assuntos
Animais Geneticamente Modificados/crescimento & desenvolvimento , Antivirais/farmacologia , Bombyx/crescimento & desenvolvimento , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Animais , Animais Geneticamente Modificados/virologia , Bombyx/efeitos dos fármacos , Bombyx/virologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/virologia
9.
Environ Pollut ; 249: 82-90, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30878865

RESUMO

Due to increased use of agrochemicals and growing concerns about ecotoxicology, the development of new insecticides, moving away from those with neurotoxic and broad spectrum effects towards insecticides that are safer for the environment and nontarget beneficial species, has been a research priority. Novaluron stands out among these newer insecticides, is an insect growth regulator that is used for the control of insect pests in crops grown close to mulberry plantations. Mulberry serves as food for the silkworm Bombyx mori, which is a nontarget insect of great economic importance to silk production. We investigated the lethal and sublethal effects of Novaluron on the development of B. mori. Larvae were segregated into experimental groups: the control groups (CGs) and the treatment groups (TGs), which were treated with the Novaluron concentration of 0.15 mL/L. Following exposure, we analyzed: larval mortality, changes in the insect life cicle and cytotoxic effects on the midgut cells. This is the first report about the Novaluron's effects on B.mori. We detected rupture in the integument, complete cessation of feeding, late development, incomplete ecdysis and production of defective cocoons. After 240 h of exposure, there was 100% mortality in TG larvae exposed in the 3rd instar and 20% mortality from larvae exposed in the 5th instar. Cytotoxic effects was observed, such as dilation of cells, emission of cytoplasmic protrusions, extreme rarefaction of the cytoplasm and nuclei, dilation of the endoplasmic reticulum in addition to changes in mitochondria, the presence of large digestive vacuoles and intercellular spaces and the presence of active caspase. Novaluron exposure impairs the midgut and may affect the physiological functions of this organ. Novaluron additionally compromises several phases of insect development, indicating the importance of toxicology studies that utilize different life stages of nontarget species to evaluate the safe use of insecticides.


Assuntos
Bombyx/fisiologia , Inseticidas/toxicidade , Compostos de Fenilureia/toxicidade , Animais , Bombyx/efeitos dos fármacos , Larva/efeitos dos fármacos , Lepidópteros , Manduca , Morus
10.
Ecotoxicol Environ Saf ; 176: 58-63, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30921697

RESUMO

Chlorantraniliprole (CAP) can induce excessive calcium release from muscle of insects, causing muscle paralysis until death, and its residues in farmland can cause poisoning in Bombyx mori (B. mori), resulting in the failure of cocooning. No reports have investigated the effects of CAP exposure on detoxification enzyme activities and detoxification-related gene expression in B. mori. In the present study, we treated mulberry leaves with CAP by the leaf-dipping method, and then B. mori larvae were continuously fed with the polluted mulberry leaves. Moreover, the detoxification enzyme activities and the expressions of detoxification-related genes in the fat body of B. mori were examined. The results showed that at 24 h after CAP exposure, the activities of P450 and GST enzymes were all significantly increased, with P450 enzymes responding fastest. CarE enzyme activity was up-regulated in 24 h, and then it was decreased compared with the control group. Furthermore, the expressions of the key genes in the PI3K/Akt/CncC signaling pathway (PI3K, PDK, Akt, CncC and Keap1) at the mRNA were significantly increased. Western blotting analysis revealed that Akt was inhibited at the protein level, resulting in decreased expression of Keap1 and increased expression of CncC. These results indicated that the PI3K/Akt/CncC signaling pathway in the fat body of B. mori responded to CAP exposure and regulated the expressions of downstream detoxification enzymes, thus enhancing the detoxifying capability of B. mori.


Assuntos
Bombyx/efeitos dos fármacos , ortoaminobenzoatos/toxicidade , Animais , Bombyx/genética , Bombyx/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Corpo Adiposo/efeitos dos fármacos , Corpo Adiposo/metabolismo , Expressão Gênica/efeitos dos fármacos , Inativação Metabólica/genética , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos
11.
Pest Manag Sci ; 75(10): 2672-2681, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30740867

RESUMO

BACKGROUND: Neonicotinoid insecticides are widely used in the prevention and control of pests in agriculture and forestry, but they can also affect the development of nontarget economic insects. In order to determine the effects of trace acetamiprid on the development of reproductive system of silkworm, we studied the gonad development and endogenous hormone metabolism in silkworms exposed to trace acetamiprid. RESULT: The silkworm showed mild poisoning symptoms after being exposed to trace acetamiprid (0.01 mg L-1 ). After 96 h of acetamiprid exposure, the body weight of silkworm was decreased by 7.67% and the ovary and fallopian tube were abnormally developed. The egg production in adults was decreased by 197 ± 29, and the egg weight was decreased by 0.52 ± 0.01 mg. Quantitative RT-PCR analysis showed that the relative expression levels of ovarian development-related genes Vg, Ovo, Otu, Sxl-S and Sxl-L were downregulated by 0.71, 0.77, 0.47, 0.67 and 0.88-fold, respectively. The transcriptional expression of ecdysone metabolism-related gene (EcR) in the ovary was downregulated by 0.46-fold while the expression of juvenile hormone-related gene (JHBP2) was upregulated by 1.36-fold. In hemolymph of acetamiprid exposed larvae, the content of ecdysone was reduced whereas the content of juvenile hormone was increased. CONCLUSION: Trace acetamiprid may cause reproductive dysfunction in silkworms through regulating the metabolism of endogenous hormones. Our study provides a reference for elucidating the mechanism of acetamiprid-induced reproductive disorders in insects. © 2019 Society of Chemical Industry.


Assuntos
Bombyx/efeitos dos fármacos , Ecdisterona/metabolismo , Inseticidas/toxicidade , Hormônios Juvenis/metabolismo , Neonicotinoides/toxicidade , Animais , Bombyx/crescimento & desenvolvimento , Feminino , Genitália/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Óvulo/efeitos dos fármacos , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Reprodução/efeitos dos fármacos
12.
Ecotoxicol Environ Saf ; 172: 388-395, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30731270

RESUMO

The widespread use of silver nanoparticles (AgNPs) has raised public concern due to their potential toxic effects on humans and the environment. Although some studies have evaluated the toxicity of nanomaterials in vertebrates, studies on their hazardous effects on insects are limited. Here we focused on different concentrations of AgNPs to silkworms, a promising model organism, to evaluate their toxic effects by omics analysis. After the silkworms were fed with 100 mg L-1 AgNPs, transcriptomics analysis showed differential expression of 43 genes: 39 upregulated and 4 downregulated. These differentially expressed genes (DEGs) were involved in the digestion process, various metabolic pathways, transmembrane transport and energy synthesis. Proteomic results for silkworms fed with 400 mg L-1 AgNPs revealed 14 significantly differentially expressed proteins: 11 downregulated and 3 upregulated. Reverse transcription-polymerase chain reaction (RT-PCR) results showed that the expression levels of eight proteins were similar to the transcription levels of their corresponding genes. As the AgNPs concentration was increased, the expression of digestive enzymes was downregulated, which damaged the silkworm tissue and suppressed the activity of the enzyme superoxide dismutase and the protein HSP 1, causing oxidative stress and the production of reactive oxygen species, which had toxic effects on the silkworm digestive system. Histopathological results showed that treatment with 400 mg L-1 AgNPs destroyed the basal lamina and the columnar cells, caused adverse effects on tissues and had the potential to induce harmful effects on the digestive system. The data presented herein provide valuable information on the hazards and risks of nanoparticle contamination. Main finding: AgNPs would downregulate some digestive enzymes, damage the tissue of midgut in silkworm, meantime induce the accumulation of reactive oxygen species which may cause oxidative stress.


Assuntos
Bombyx/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Bombyx/genética , Bombyx/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Estresse Oxidativo , Proteômica , Espécies Reativas de Oxigênio/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Superóxido Dismutase/metabolismo
13.
FEMS Microbiol Lett ; 366(2)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30596999

RESUMO

Although Enterobacter sp. 532 shows pathogenicity in Bombyx mori, the insecticidal mechanisms are unclear. Here, we identified and characterised an insecticidal protein from Enterobacter. The insecticidal protein was purified from the strain and inoculated into B. mori larvae. Intracellular proteins were prepared, purified and separated by preparative native polyacrylamide gel electrophoresis (PAGE); one protein band had insecticidal activity. Sodium dodecyl sulfate-PAGE showed the presence of several bands, indicating that the insecticidal protein formed a complex. Peptide mass fingerprinting of a prominent 255.3-kDa band revealed 64 peptides that matched one protein with 33.0% sequence coverage. This protein was a homologue of the A component of the toxin complex (Tc), and the VRP1 domain was conserved; thus, the gene was named itcA (insecticidal toxin complex A). In the itcA downstream region, B and C component gene homologues were found, and these genes were located on an 86.2-kb contig sequence. Two repA genes and 27 genes related to conjugation transfer of plasmids were located on the contig, suggesting that the contig originated from a mobilisable plasmid. Therefore, these findings suggested that the strain may have acquired the Tc genes by horizontal transfer. This is the first description of Tc produced by the genus Enterobacter.


Assuntos
Toxinas Bacterianas/toxicidade , Bombyx/efeitos dos fármacos , Proteínas Hemolisinas/toxicidade , Inseticidas/farmacologia , Animais , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/isolamento & purificação , Bombyx/microbiologia , Enterobacter/classificação , Enterobacter/genética , Enterobacter/isolamento & purificação , Enterobacter/metabolismo , Proteínas Hemolisinas/química , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/isolamento & purificação , Inseticidas/química , Inseticidas/metabolismo , Filogenia , Domínios Proteicos
14.
Gen Comp Endocrinol ; 274: 97-105, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668972

RESUMO

In the present study, the roles of a major serine/threonine protein phosphatase 2A (PP2A) in prothoracicotropic hormone (PTTH)-stimulated prothoracic glands (PGs) of Bombyx mori were evaluated. Immunoblotting analysis showed that Bombyx PGs contained a structural A subunit (A), a regulatory B subunit (B), and a catalytic C subunit (C), with each subunit undergoing development-specific changes. The protein levels of each subunit were not affected by PTTH treatment. However, the highly conserved tyrosine dephosphorylation of PP2A C subunit (PP2Ac), which appears to be related to activity, was increased by PTTH treatment in a time-dependent manner. We further demonstrated that phospholipase C (PLC), Ca2+, and reactive oxygen species (ROS) are upstream signaling for the PTTH-stimulated dephosphorylation of PP2Ac. The determination of PP2A enzymatic activity showed that PP2A enzymatic activity was stimulated by PTTH treatment both in vitro and in vivo. Okadaic acid (OA), a specific PP2A inhibitor, prevented the PTTH-stimulated dephosphorylation of PP2Ac and reduced both basal and PTTH-stimulated PP2A enzymatic activity. The determination of ecdysteroid secretion showed that treatment with OA did not affect basal ecdysteroid secretion but did significantly inhibit PTTH-stimulated ecdysteroid secretion, indicating that PTTH-stimulated PP2A activity is involved in ecdysteroidogenesis. Treatment with OA stimulated the basal phosphorylation of the extracellular signal-regulated kinase (ERK) and 4E-binding protein (4E-BP) without affecting PTTH-stimulated ERK and 4E-BP phosphorylation. From these results, we hypothesize that PTTH-regulated PP2A signaling is a necessary component for the stimulation of ecdysteroidogenesis, potentially by mediating the link between ERK and TOR signaling pathways.


Assuntos
Estruturas Animais/metabolismo , Bombyx/enzimologia , Hormônios de Inseto/farmacologia , Proteína Fosfatase 2/metabolismo , Acetilcisteína/farmacologia , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Estruturas Animais/efeitos dos fármacos , Animais , Bombyx/efeitos dos fármacos , Cálcio/farmacologia , Ecdisteroides/farmacologia , Estrenos/farmacologia , Fatores de Iniciação em Eucariotos/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Subunidades Proteicas/metabolismo , Pirrolidinonas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribonucleotídeos/farmacologia , Transdução de Sinais
15.
Arch Virol ; 164(1): 17-25, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30225520

RESUMO

Oral inoculation of entomopoxvirus spindles, microstructures composed of fusolin protein, causes disruption of the peritrophic matrix (PM), a physical barrier against microbe infection, in the insect midgut. Although the atomic structure of fusolin has been determined, little has been directly elucidated of the mechanism of disruption of the PM. In the present study, we first performed an immunohistochemical examination to determine whether fusolin acts on the PM directly or indirectly in the midgut of Bombyx mori larvae that were inoculated with spindles of Anomala cuprea entomopoxvirus. This revealed that the PM, rather than the midgut cells, was the attachment site for fusolin. Fusolin broadly attached to the PM from the anterior to the posterior region, both to its ectoperitrophic and endoperitrophic surfaces and within the PM. These results likely explain why the whole of the PM is rapidly disintegrated. Second, we administered protease inhibitors mixed with spindles and observed decreased midgut protease activity and reduced disruption of the PM. This suggests that midgut protease(s) is also positively involved in PM disruption. Based on the present results, we propose an overall mechanism for the disruption of the PM by administration of fusolin.


Assuntos
Bombyx/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Peptídeo Hidrolases/metabolismo , Proteínas Virais/farmacologia , Administração Oral , Animais , Inseticidas/farmacologia , Larva/efeitos dos fármacos
16.
Pestic Biochem Physiol ; 152: 45-54, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30497710

RESUMO

1-Deoxynojirimycin (DNJ) is a natural d-glucose analogue from mulberry with promising physiological activity in vivo. Up to the present, the antidiabetic effects of DNJ on lowering blood sugar and accelerating lipid metabolism in mammals were broadly reported, but the specific character of DNJ against insects was vastly ignored. In this study, a toxicological test of DNJ againgst eri-silkworm, Samia cynthia ricini was carried out to investigate the potential of DNJ in insect management. Further, a method of nuclear magnetic resonance (NMR) metabonomics and real-time qPCR (RT-qPCR) were performed to analyze the alteration in midgut of eri-silkworm caused by DNJ. The result of toxicology showed that 5% and 10% DNJ could significantly inhibit the development of third-instar larvae on day 1-5, and mass deaths happened in DNJ groups on day 3-5. The quantitative analysis of 1H NMR in fifth-instar larvae showed that trehalose level increased in midgut of 0, 6 and 12 h DNJ groups, while the concentrations of glucose, lactate, alanine, pyruvate, α-ketoglutarate and fumarate were reduced in varying degrees. Meanwhile, principal component analysis (PCA) indicated that there were significant differences in the metabolic profiles among 12 h DNJ groups and the control group. In addition, RT-qPCR results displayed that four genes coding α-glucosidase, trehalase (THL) and lactate dehydrogenase (LDH) were lowered in expression of 12 h DNJ groups. Simultaneously, THL activity was significantly lowerd in 12 h DNJ groups. These mutually corroborated results indicated that the backbone pathways of energy metabolism, including hydrolysis of trehalose and glycogens, glycolysis and tricarboxylic acid (TCA) cycle were significantly inhibited by DNJ. Thus, the specific mechanism of DNJ efficiently suppressing the growth and energy metabolism of eri-silkworm was explored in this study, providing the potential of DNJ as to the production of botanical insecticide.


Assuntos
1-Desoxinojirimicina/toxicidade , Bombyx/efeitos dos fármacos , Inseticidas/toxicidade , Morus , Animais , Bombyx/fisiologia , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Larva/efeitos dos fármacos , Larva/fisiologia , Metabolômica , Transcrição Genética
17.
J Toxicol Sci ; 43(12): 697-709, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30518707

RESUMO

Silver nanoparticles (Ag-NPs) are known as a noble metal, and owing to their exclusive properties, their use is widespread in consumer products and they are mostly incorporated into food packaging and food contact products. The aim of this work was to evaluate the effects of direct ingestion of Ag-NPs through food to assess their toxicity effects on the growth and development of silkworms at different concentrations (1 mg·L-1 to 100 mg·L-1), in addition to the examination of the distribution of Ag-NPs in the silkworm body and midgut histopathological analysis. RNA sequencing was performed to investigate the transcriptomic responses to Ag-NPs exposure. Our results show that the highest Ag-NPs' concentrations induced a significant increase in the silkworm body weight with histopathological changes in the midgut compared to the control group. The gene ontology (GO) and pathway enrichment analysis for differentially expressed genes showed that Ag-NPs altered the gene expressions and that they were significantly involved in carbohydrate metabolism, digestive system, and energy metabolism. These findings indicate that the Ag-NPs may induce harmful effects on the primary target organs (alimentary system) with energy deregulation and nutrition digestion and absorption imbalance. This study is an important step in understanding the molecular mechanisms of Ag-NPs' toxicity in vivo.


Assuntos
Bombyx/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Bombyx/genética , Trato Gastrointestinal/patologia , Larva/efeitos dos fármacos , Larva/genética , Transcriptoma/efeitos dos fármacos
18.
Zoolog Sci ; 35(6): 487-493, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30520362

RESUMO

To clarify the molecular mechanism of prevention of entry into diapause in Bombyx mori by HCl treatment, we biochemically analyzed mitochondrial Ca2+ -dependent solute carrier protein (MCSC) in diapause eggs treated with HCl solution. Our previous studies revealed that HCl treatment causes Ca2+ to efflux from diapause eggs. Therefore, we attempted to analyze MCSC, which is known to associate with Ca2+ . The isolated cDNA of B. mori MCSC (BmMCSC) had an open reading flame (ORF) of 667 amino acid residues, and the ORF contained two EF-hand calcium-binding domains and three characteristic features of the mitochondrial solute carrier superfamily. The gene expression level of BmMCSC increased by HCl treatment. A Ca2+ binding assay indicated that recombinant BmMCSC (rBmMCSC) shows an affinity with Ca2 + . The distribution of BmMCSC was investigated with an immunohistochemical technique using antisera against BmMCSC in diapause eggs and HCl-treated diapause eggs. BmMCSC was localized in serosa cells in both eggs. These data may suggest that BmMCSC is activated by intracellular Ca2+ or efflux Ca2+ by HCl treatment, and that it plays a role in the molecular mechanisms of artificial diapause prevention or the breaking of diapause in the silkworm.


Assuntos
Bombyx/metabolismo , Ácido Clorídrico/farmacologia , Proteínas de Insetos/metabolismo , Proteínas Mitocondriais/metabolismo , Animais , Bombyx/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Proteínas de Insetos/genética , Proteínas Mitocondriais/genética , Distribuição Tecidual
19.
Environ Toxicol Pharmacol ; 64: 41-47, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30293049

RESUMO

Bombyx mori was used as a model to evaluate the reproductive toxicity of NaF in insects. Significant reduction in cocoon quality, survival rate, fecundity, and hatchability were observed upon NaF treatment groups. Fluoride determination indicated that F- has a cumulative effect on the gonad of silkworm. High-performance liquid chromatography revealed that the testosterone content of males was decreased in NaF-treated groups, and enzyme-linked immunosorbent assay showed that the estradiol content was decreased in NaF-treated females. Ultrastructural observation of testicles of silkworm larvae revealed mitochondrial turgescence, endoplasmic reticulum destruction, the appearance of vacuoles and lysosomes, and apoptosis and necrosis of cells in NaF-treated groups. Altered tail length and tail DNA content in Comet assays further confirmed DNA damage in NaF-treated larvae. We demonstrated reproductive toxicity of fluoride toward silkworm at physiological and biochemical levels, and the results provide a theoretical basis for revealing the reproductive toxicity of fluoride in terrestrial insects.


Assuntos
Bombyx/efeitos dos fármacos , Fluoreto de Sódio/toxicidade , Animais , Bombyx/fisiologia , Ensaio Cometa , Dano ao DNA , Estradiol/metabolismo , Feminino , Larva/efeitos dos fármacos , Larva/fisiologia , Masculino , Reprodução/efeitos dos fármacos , Testículo/efeitos dos fármacos , Testículo/patologia
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