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1.
Ecotoxicol Environ Saf ; 208: 111582, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396105

RESUMO

In recent years, heavy metal pollution has caused immeasurable harm to the environment. As an emerging technology, phytoremediation technology has gained a place in the treatment of heavy metal pollution with its unique advantages. This study analyzes the toxic effects of mulberry (Morus alba) seeds, seedling growth and silkworm under heavy metal stress of lead (Pb) and cadmium (Cd), and explore the accumulation and migration of Pb and Cd in the soil-mulberry tree-silkworm system. The main results were as follows: (1) Seed germination and potted seedling experiments were conducted under heavy metal Pb and Cd stresses, and it was found that Pb and Cd had inhibitory effects on mulberry seed germination, growth and photosynthesis of mulberry seedlings, and as the concentration of heavy metals increased, the stronger the inhibitory effect. Moreover, Pb and Cd have a synergistic effect under compound stress. (2) The accumulation and transfer rules of Pb and Cd ions in mulberry were different. The content of Pb in mulberry was root > leaf > stem and the content of Cd was root > stem > leaf. The combined stress promoted the transfer of Pb and Cd from the underground part to the aerial portion of mulberry. (3) The silkworm feeds on mulberry leaves contaminated with heavy metals in this experiment and found that: with the increase of silkworm feeding, the heavy metal content in the silkworm body increased significantly, but the content remained in the silkworm body was less, most of it was excreted with silkworm excrement. Combined stress has no significant effect on the detoxification mechanism of silkworm. It is indispensable to think of the synergistic effect of heavy metals on plants germination when seeds are used for phytoremediation.


Assuntos
Bombyx/fisiologia , Cádmio/toxicidade , Cadeia Alimentar , Chumbo/toxicidade , Morus/fisiologia , Poluentes do Solo/toxicidade , Solo/química , Animais , Biodegradação Ambiental , Cádmio/análise , Cádmio/metabolismo , Frutas/química , Metais Pesados/análise , Fotossíntese , Folhas de Planta/química , Plântula/química , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
2.
Ecotoxicol Environ Saf ; 210: 111888, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33421719

RESUMO

This study aimed to explore the toxicity of environmental residues of graphene oxide nanoparticles (GONPs) to reproduction of Lepidopteron insects using both ovary cell line (BmN) and individual female Bombyx mori as the research subjects. The results showed that GONPs dose dependently affect BmN cells. At higher concentrations (>25 mg/L), GONPs led to oxidative stress, ROS accumulation and DNA damage in BmN cells and significantly reduced their survival rate (p ≤ 0.05). Moreover, feeding female B. mori larvae with mulberry leaves treated with 25 mg/L GONPs significantly decreased their gonadosomatic index (GSI) by 40.84%, and increased oxidation levels and antioxidant enzyme activity in silkworm ovary tissues. Pathological analysis found that exposure to GONPs decreased the numbers of both oogonia and oocytes in ovarian tissues, increased the formation of peroxisome and vacuoles in follicle cells, reduced the transcription of genes (Vg, Ovo, Sxl-s, Sxl-l, and Otu) related to ovarian development in B. mori by 0.61, 0.65, 0.75, 0.72, and 0.42-fold, respectively, and lowered the amount of spawning by 52.25%. Overall, these results revealed that GONPs exposure is toxic to the reproduction of B. mori. The underlying mechanism is that oxidative stress due to GONPs causes oxidative damage to DNA, damages ovarian tissues, as well as hinders B. mori development and spawning. Thus, this study provides important experimental data for safety evaluation of reproductive toxicity due to GONPs exposure.


Assuntos
Bombyx/efeitos dos fármacos , Grafite/toxicidade , Nanopartículas/toxicidade , Animais , Bombyx/fisiologia , Linhagem Celular , Dano ao DNA , Feminino , Masculino , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Oócitos/patologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Reprodução/efeitos dos fármacos
3.
Chemosphere ; 262: 127891, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799150

RESUMO

Fluoride generally exists in the natural environment, and has been reported to induce serious environmental hazard to animals, plants, and even humans via ecological cycle. Silkworm, Bombyx mori, which showed significant growth and reproductivity reduction when exposed to fluoride, has become a model to evaluate the toxicity of fluoride. However, the detailed mechanism underlying fluoride toxicity and corresponding transport proteins remain unclear. In this study, we performed RNA-seq of the larval midgut and fat body with fluoride exposure and normal treatment. Differential analysis showed that there were 4405 differentially expressed genes in fat body and 4430 DEGs in midgut with fluoride stress. By Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, we identified several key pathways involved in the fluoride exposure and poisoning. We focused on the oxidative phosphorylation and MAPK signal pathway. QRT-PCR confirmed that oxidative phosphorylation process was remarkably inhibited by fluoride exposure and resulted in the blocking of ATP synthesis. The MAPK signal pathway was stimulated via phosphorylation signal transduction. Moreover, by protein structure analysis combined with the DEGs, we screen 36 potential membrane proteins which might take part in transporting fluoride. Taken together, the results of our study expanded the underlying mechanisms of fluoride poisoning on silkworm larval growth and development, and implied potential fluoride transport proteins in silkworm.


Assuntos
Bombyx/fisiologia , Fluoretos/toxicidade , Substâncias Perigosas/toxicidade , Tecido Adiposo/metabolismo , Animais , Bombyx/metabolismo , Sistema Digestório/metabolismo , Corpo Adiposo/metabolismo , Perfilação da Expressão Gênica/métodos , Inativação Metabólica , Larva/genética , Transcriptoma/fisiologia
4.
Ecotoxicol Environ Saf ; 209: 111759, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33341695

RESUMO

Ionic liquids (ILs) have been reported to be a potential water and soil pollutant, whose toxicity has gained much attention in recent years. In this work, silkworm larvae were used as a novel in vivo model to assess the biotoxicity of ILs, which were performed by three steps. The first step was to determine the susceptibility of different silkworm strains to ILs. Data showed that Jingsong×haoyue was the most susceptible one among three silkworm strains (Jingsong×haoyue, P50, and Yi16) for evaluating the biological effects of ILs. The second step was to compare the toxicity of ILs with different structures using the larvae of Jingsong×haoyue. It was found that three representative ILs, 1-octyl-3-methylimidazole chloride ([C8mim]Cl), N-octyl-3-methylpyridine chloride ([C8mpy]Cl), and 1-octyl-3-methylimidazole tetrafluoroborate ([C8mim]BF4), had significant toxic effects on the growth and development of the larvae with 24 h median lethal concentration (24 h-LC50) values of 112.3, 156.3, and 68.9 µg g-1, respectively, indicating that the types of anions and cations had impacts on the toxicity of ILs. The last step was targeted at investigating responses of the larvae to the exposure of ILs. It was observed that remarkable physiological and biochemical responses occurred in different tissues of the larvae. For example, activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in different tissues increased significantly to form an active protective mechanism for alleviating the toxic effects of ILs. Additionally, an increase of malondialdehyde (MDA) contents was found in the larvae. The data suggested that ILs could induce lipid peroxidation and cellular damage, which may be the main reason for toxicity of ILs to the larvae. Therefore, silkworm larvae could be used as a susceptible and reliable in vivo model to evaluate the toxicity of ILs, and the results are helpful to reveal their toxic mechanism to insects.


Assuntos
Substâncias Perigosas/toxicidade , Líquidos Iônicos/toxicidade , Animais , Ânions/química , Bombyx/metabolismo , Bombyx/fisiologia , Catalase/metabolismo , Cátions , Cloretos , Estudos de Viabilidade , Imidazóis , Larva/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído , Superóxido Dismutase/metabolismo , Testes de Toxicidade
5.
PLoS Biol ; 18(9): e3000828, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32936797

RESUMO

Many herbivorous insects are mono- or oligophagous, having evolved to select a limited range of host plants. They specifically identify host-plant leaves using their keen sense of taste. Plant secondary metabolites and sugars are thought to be key chemical cues that enable insects to identify host plants and evaluate their quality as food. However, the neuronal and behavioral mechanisms of host-plant recognition are poorly understood. Here, we report a two-factor host acceptance system in larvae of the silkworm Bombyx mori, a specialist on several mulberry species. The first step is controlled by a chemosensory organ, the maxillary palp (MP). During palpation at the leaf edge, the MP detects trace amounts of leaf-surface compounds, which enables host-plant recognition without biting. Chemosensory neurons in the MP are tuned with ultrahigh sensitivity (thresholds of attomolar to femtomolar) to chlorogenic acid (CGA), quercetin glycosides, and ß-sitosterol (ßsito). Only if these 3 compounds are detected does the larva make a test bite, which is evaluated in the second step. Low-sensitivity neurons in another chemosensory organ, the maxillary galea (MG), mainly detect sucrose in the leaf sap exuded by test biting, allowing larvae to accept the leaf and proceed to persistent biting (feeding). The two-factor host acceptance system reported here may commonly underlie stereotyped feeding behavior in many phytophagous insects and determine their feeding habits.


Assuntos
Bombyx/fisiologia , Comportamento de Escolha , Dieta , Comportamento Alimentar/fisiologia , Larva/fisiologia , Papilas Gustativas/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Comportamento Animal/fisiologia , Bombyx/anatomia & histologia , Bombyx/crescimento & desenvolvimento , Células Quimiorreceptoras/fisiologia , Quimiotaxia/fisiologia , Sinais (Psicologia) , Comportamento Exploratório/fisiologia , Interações Hospedeiro-Parasita/fisiologia , Larva/anatomia & histologia , Larva/citologia , Morus/química , Folhas de Planta/química , Paladar/fisiologia , Papilas Gustativas/anatomia & histologia
6.
Arch Insect Biochem Physiol ; 105(2): e21732, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32783274

RESUMO

In this study, glutathione-S-transferase pull-down combined with mass spectrometry techniques were used to identify the candidate proteins interacting with protein tyrosine phosphatase of the Bombyx Mori nucleopolyhedrovirus in the B. mori (BmNPV-PTP) brain. A total of 36 proteins were identified from BmNPV-PTP coprecipitate samples by searching the NCBI_Bombyx Mori database with the original mass spectrum data. Among those proteins, the interaction between BmNPV-PTP and B. mori cyclophilin A may accelerate the apoptosis of certain nerve cells involved in regulating behavior, and thus may be an inducer of enhanced locomotor activity (ELA). After the BmNPV invasion, BmNPV-PTP binding to peripheral-type benzodiazepine receptors may initiate a series of abnormal cascades of the nervous system, which results in abnormal hyperactive behavior in B. mori. Besides this, vacuolar ATP synthase catalytic subunit A, annexin, and several enzymes for energy conversion were identified, which may play a role in enhancing viral entry and infectivity and provide energy for enhancing the locomotor activity of B. mori. In general, the results of this study will facilitate the understanding of the molecular mechanisms underlying the ELA of B. mori larva induced by BmNPV.


Assuntos
Bombyx/virologia , Nucleopoliedrovírus/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Animais , Bombyx/fisiologia , Encéfalo/metabolismo , Encéfalo/virologia , Interações Hospedeiro-Patógeno , Proteínas de Insetos/metabolismo , Larva/fisiologia , Larva/virologia , Atividade Motora/fisiologia , Nucleopoliedrovírus/fisiologia , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/fisiologia , Proteínas Virais/metabolismo
7.
Ecotoxicol Environ Saf ; 202: 110914, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800249

RESUMO

Bombyx mori(Linnaeus, 1758) is an important economical insect, and the sericulture is a flourishing industry in many developing countries. Pyriproxyfen, a juvenile hormone pesticide, is often applied to cultivations widely in the world, and its exposure often resulted in silk yield reduction and non-cocooning. However, the effect of pyriproxyfen exposure on cocooning and gene expression level in the silk gland of B. mori has not been studied yet, and this study focused on the above issues. The result indicated that pyriproxyfen exposure can lead to silk gland injury, reduction of silk yield and cocooning rate. Furthermore, the expression levels of silk protein synthesis related genes were down regulated significantly. The same change trends were shown between PI3K/Akt and CncC/Keap1 pathway, which is the expressions of key genes can be elevated by pyriproxyfen exposure. In addition, the activity of detoxification enzymes (P450, GST and CarE) and the expression levels of detoxification genes were elevated after pyriproxyfen exposure, suggesting that detoxification enzymes may play an important role in detoxification of pyriproxyfen in silk gland. These results provided possible clues to the silk gland injury and gene transcriptional level changes in silkworm after pyriproxyfen exposure.


Assuntos
Bombyx/fisiologia , Inseticidas/toxicidade , Piridinas/toxicidade , Animais , Bombyx/efeitos dos fármacos , Bombyx/genética , Regulação para Baixo , Proteínas de Insetos/genética , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Larva/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Biossíntese de Proteínas , Seda/biossíntese , Seda/genética , Seda/metabolismo
8.
Chemosphere ; 259: 127481, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650163

RESUMO

Zinc Oxide nanoparticles (ZnO NPs) has been heavily used in the industry, and increasing concerns on the ecotoxicity has arisen due to the risk of release into the environment. In this work, silkworm was used here as a model organism to study the toxicity of ZnO NPs, due to the presence of a conserved immune response as well as a pharmacokinetics similar to mammals. Zn accumulation, biodistribution and toxicity in silkworms were monitored at different time points after a subcutaneous injection. The highest cumulative content of ZnO NPs was detected in the midgut. The results of catalytic activity studies confirmed that the antioxidant enzymes (SOD, CAT, GSH-PX) in midgut cells were expressed in response to ZnO NPs. The expression of genes (Dronc and Caspase-1) related to apoptosis was increased, while the Trt gene was down-regulated. A possible mechanism was proposed for toxicity of ZnO NPs to silkworms.


Assuntos
Bombyx/fisiologia , Nanopartículas Metálicas/toxicidade , Óxido de Zinco/toxicidade , Animais , Antioxidantes/metabolismo , Apoptose , Bombyx/metabolismo , Nanopartículas , Distribuição Tecidual , Testes de Toxicidade Aguda
9.
Gene ; 760: 144998, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32717304

RESUMO

The life cycle of holometabolous insects involves different stages and cathepsin plays an important role in insect metamorphosis. In the present study, we investigated the function of Bombyx mori cathepsin-L (Bm-CatL) during metamorphosis and analyzed their role in programmed cell death (PCD) of the fat body. The results showed that knockdown of Bm-CatL by RNA interference led to abnormal pupation and a delay in fat body degradation during metamorphosis. Furthermore, PCD inhibition was observed in the fat body after downregulation of Bm-CatL. To confirm this finding, PCD was induced in Bombyx mori embryonic (BmE) cells by ultraviolet ray irradiation. We found that the PCD of BmE cells was weakened after knocking down Bm-CatL. Moreover, overexpression of Bm-CatL in cells promoted PCD. Overall, our results showed that Bm-CatL is involved in the degradation of internal tissues and promotes the PCD of cells involved in the pupation of silkworms. Thus, this study provides us with a better understanding for function of cathepsin-L during metamorphosis.


Assuntos
Bombyx/fisiologia , Catepsina L/metabolismo , Tecido Adiposo/metabolismo , Animais , Apoptose/fisiologia , Bombyx/genética , Bombyx/metabolismo , Corpo Adiposo/metabolismo , Proteínas de Insetos/metabolismo , Metamorfose Biológica , Interferência de RNA
10.
PLoS Genet ; 16(7): e1008907, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667927

RESUMO

Holometabolous insects have distinct larval, pupal, and adult stages. The pupal stage is typically immobile and can be subject to predation, but cocoon offers pupal protection for many insect species. The cocoon provides a space in which the pupa to adult metamorphosis occurs. It also protects the pupa from weather, predators and parasitoids. Silk protein is a precursor of the silk used in cocoon construction. We used the silkworm as a model species to identify genes affecting silk protein synthesis and cocoon construction. We used quantitative genetic analysis to demonstrate that ß-1,4-N-acetylglucosaminidase 1 (BmGlcNase1) is associated with synthesis of sericin, the main composite of cocoon. BmGlcNase1 has an expression pattern coupled with silk gland development and cocoon shell weight (CSW) variation, and CSW is an index of the ability to synthesize silk protein. Up-regulated expression of BmGlcNase1 increased sericin content by 13.9% and 22.5% while down-regulation reduced sericin content by 41.2% and 27.3% in the cocoons of females and males, respectively. Genomic sequencing revealed that sequence variation upstream of the BmGlcNase1 transcriptional start site (TSS) is associated with the expression of BmGlcNase1 and CSW. Selective pressure analysis showed that GlcNase1 was differentially selected in insects with and without cocoons (ω1 = 0.044 vs. ω2 = 0.154). This indicates that this gene has a conserved function in the cocooning process of insects. BmGlcNase1 appears to be involved in sericin synthesis and silkworm cocooning.


Assuntos
Acetilglucosaminidase/genética , Bombyx/genética , Cruzamento , Domesticação , Animais , Bombyx/fisiologia , Feminino , Regulação da Expressão Gênica/genética , Larva/genética , Larva/crescimento & desenvolvimento , Masculino , Biossíntese de Proteínas/genética , Seda/genética
11.
PLoS Genet ; 16(6): e1008622, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32520935

RESUMO

Insect courtship and mating depend on integration of olfactory, visual, and tactile cues. Compared to other insects, Bombyx mori, the domesticated silkworm, has relatively simple sexual behaviors as it cannot fly. Here by using CRISPR/Cas9 and electrophysiological techniques we found that courtship and mating behaviors are regulated in male silk moths by mutating genes in the sex determination cascade belonging to two conserved pathways. Loss of Bmdsx gene expression significantly reduced the peripheral perception of the major pheromone component bombykol by reducing expression of the product of the BmOR1 gene which completely blocked courtship in adult males. Interestingly, we found that mating behavior was regulated independently by another sexual differentiation gene, Bmfru. Loss of Bmfru completely blocked mating, but males displayed normal courtship behavior. Lack of Bmfru expression significantly reduced the perception of the minor pheromone component bombykal due to the down regulation of BmOR3 expression; further, functional analysis revealed that loss of the product of BmOR3 played a key role in terminating male mating behavior. Our results suggest that Bmdsx and Bmfru are at the base of the two primary pathways that regulate olfactory-based sexual behavior.


Assuntos
Bombyx/genética , Genes de Insetos , Preferência de Acasalamento Animal , Atrativos Sexuais/metabolismo , Processos de Determinação Sexual/genética , Animais , Bombyx/metabolismo , Bombyx/fisiologia , Feminino , Masculino , Receptores de Feromonas/genética , Receptores de Feromonas/metabolismo , Atrativos Sexuais/genética , Olfato
12.
Arch Insect Biochem Physiol ; 105(1): e21719, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32515115

RESUMO

Gender sensitivity to ambient heat, despite well known in insect species, how it manifests during young and late larval instars of Bombyx mori is still unclear. To uncover this cryptic feature, different instars male and female larvae were subjected to varied thermal stress separately and sex-stage specific expression of proteins was investigated. Interestingly, heat shock proteins (HSPs) 90 and 70 were expressed differently in all the instars and also between male and female larvae as confirmed by immunoblot assay. Besides up- and downregulation of few HSPs and other normal proteins, discreet expression of protein was noticed in the two-dimensional gel electrophoresis of male than female larvae which were identified as HSP70 by mass spectrometry. Furthermore, quantitative polymerase chain reaction results show 3.98- and 4.86-fold higher levels of Bmhsp70 and Bmhsp90 transcripts in male and female larvae, respectively, as a response to 40°C heat shock (HS) treatment. Conversely, in spite of the massive production of HSPs due to HS at 45°C, all the larvae were found dead, which is a strong proof of concept for autophagy. Comparatively, female larvae HS at 40°C succeed to spin cocoons with increased weight and silk contents than non-HS larvae. Comprehensively, in the present study, we have noticed a strong correlation for the first time that Bmhsp90 and Bmhsp70 genes expressions due to thermal stress are not only sex specific but also explicit preferential and coordinated action on survivability and biosynthetic potential of the silkworm, B. mori larvae during different instars.


Assuntos
Bombyx/fisiologia , Proteínas de Choque Térmico/genética , Proteínas de Insetos/genética , Proteoma/genética , Animais , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Feminino , Proteínas de Choque Térmico/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Proteoma/metabolismo , Fatores Sexuais
13.
Arch Insect Biochem Physiol ; 105(1): e21718, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32515853

RESUMO

The autophagy process involves a series of autophagy-related (Atg) proteins, which are conserved in eukaryotes. ULK1/Atg1-ATG13/Atg13 is the core protein complex for autophagy initiation in response to nutrient and hormone signaling. However, how Atg13 is regulated to participate in autophagy is unclear in insects. Here in Bombyx mori, the variation of BmAtg13 was correlated with autophagy induced by steroid hormone 20-hydroxyecdysone (20E) or starvation. Developmental profiles from feeding to prepupal stage revealed that there were two bands of BmAtg13 protein detected by western blot analysis, therein the upper band was intensively decreased, while the lower band was significantly increased which was in accordance with its mRNA variation; and immunofluorescent staining indicated that BmAtg13 was nucleocytoplasmic translocated during larval-pupal metamorphosis when autophagy was dramatically induced. BmAtg13 knockdown and overexpression both inhibits autophagy. Besides, 20E treatment-induced BmAtg13 gene expression, while blocking 20E signaling transduction by knockdown of BmUsp reduced both gene expression and protein level of BmAtg13. These results reveal that BmAtg13 is required for 20E- and starvation-induced autophagy in B. mori, which provides the foundation for further related studies.


Assuntos
Proteínas Relacionadas à Autofagia/genética , Autofagia/genética , Bombyx/fisiologia , Proteínas de Insetos/genética , Animais , Proteínas Relacionadas à Autofagia/metabolismo , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Ecdisterona/metabolismo , Privação de Alimentos , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
14.
Chemosphere ; 257: 127203, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32480083

RESUMO

Information on the occurrence and effects of nanoplastics in ecosystems worldwide currently represent one of the main challenges from the ecotoxicological point of view. This is particularly true for terrestrial environments, in which nanoplastics are released directly by human activities or derive from the fragmentation of larger plastic items incorrectly disposed. Since insects can represent a target for these emerging contaminants in land-based community, the aim of this study was the evaluation of ingestion of 0.5 µm polystyrene nanoplastics and their effects in silkworm (Bombyx mori) larvae, a useful and well-studied insect model. The ingestion of nanoplastics, the possible infiltration in the tissues and organ accumulation were checked by confocal microscopy, while we evaluated the effects due to the administered nanoplastics through a multi-tier approach based on insect development and behaviour assessment, as endpoints at organism level, and the measurements of some biochemical responses associated with the imbalance of the redox status (superoxide dismutase, catalase, glutathione s-transferase, reactive oxygen species evaluation, lipid peroxidation) to investigate the cellular and molecular effects. We observed the presence of microplastics in the intestinal lumen, but also inside the larvae, specifically into the midgut epithelium, the Malpighian tubules and in the haemocytes. The behavioural observations revealed a significant (p < 0.05) increase of erratic movements and chemotaxis defects, potentially reflecting negative indirect effects on B. mori survival and fitness, while neither effect on insect development nor redox status imbalance were measured, with the exception of the significant (p < 0.05) inhibition of superoxide dismutase activity.


Assuntos
Bombyx/fisiologia , Nanopartículas/toxicidade , Poliestirenos/toxicidade , Animais , Bombyx/efeitos dos fármacos , Sistema Digestório/metabolismo , Ingestão de Alimentos , Ecossistema , Ecotoxicologia , Larva/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Nanopartículas/química , Oxirredução , Plásticos/farmacologia , Poliestirenos/química , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase
15.
Behav Processes ; 175: 104121, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32259625

RESUMO

Nowadays we can find a number of experiments that have showed the importance of learning in several situations related with survival of many animal species. For instance, knowledge acquired in the early stages of life could be crucial on the choice of egg-laying site. In this study we explored the influence of Pavlovian conditioning of silkworm larvae on their oviposition behaviour as adult female moths. For this, the larvae learning have to survive the metamorphosis and be shown in oviposition choice. In acquisition phase, a larvae group experienced an odour (conditioned stimulus) paired with mulberry leaves (unconditioned stimulus), another one experienced the odour and the mulberry leaves in an unpaired way and the last one experienced the odour alone during this phase. The results show that when these larvae became moths, only the first group preferred to lay their eggs near the odour when it was present during the test, so that associations learned during the larval stage seem to influence oviposition behaviour during adulthood.


Assuntos
Associação , Comportamento Animal/fisiologia , Bombyx/fisiologia , Comportamento de Escolha/fisiologia , Condicionamento Clássico/fisiologia , Larva/fisiologia , Oviposição/fisiologia , Animais , Feminino
16.
Int J Mol Sci ; 21(7)2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32276369

RESUMO

Sex determination and differentiation are nearly universal to all eukaryotic organisms, encompassing diverse systems and mechanisms. Here, we identified a spliceosomal protein gene BmSPX involved in sex determination of the lepidopeteran insect, Bombyx mori. In a transgenic silkworm line that overexpressed the BmSPX gene, transgenic silkworm males exhibited differences in their external genitalia compared to wild-type males, but normal internal genitalia. Additionally, transgenic silkworm females exhibited a developmental disorder of the reproductive organs. Upregulation of BmSPX significantly increased the expression levels of sex-determining genes (BmMasc and BmIMP) and reduced the female-type splice isoform of Bmdsx, which is a key switch gene downstream of the sex-determination pathway. Additionally, co-immunoprecipitation assays confirmed an interaction between the BmSPX protein and BmPSI, an upstream regulatory factor of Bmdsx. Quantitative real-time PCR showed that BmSPX over-expression upregulated the expression of the Hox gene abdominal-B (Adb-B), which is required for specification of the posterior abdomen, external genitalia, and gonads of insects, as well as the genes in the Receptor Tyrosine Kinase (RTK) signaling pathway. In conclusion, our study suggested the involvement of BmSPX, identified as a novel regulatory factor, in the sex-determination pathway and regulation of reproductive organ development in silkworms.


Assuntos
Bombyx/fisiologia , Genitália/metabolismo , Proteínas de Insetos/metabolismo , Processos de Determinação Sexual , Animais , Animais Geneticamente Modificados , Bombyx/genética , Regulação da Expressão Gênica , Gônadas/metabolismo , Proteínas de Insetos/fisiologia , Masculino , Processamento de RNA , Spliceossomos
17.
Sci Rep ; 10(1): 5615, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221410

RESUMO

Caterpillars of the silk moth genus Hyalophora (Lepidoptera; Saturniidae) construct multilayered cocoons that function as overwintering housing during the pupal to adult developmental period. While all cocoons share the primary function of protecting the developing moth, cocoons spun by different Hyalophora silk moth species vary significantly in architectural features and in the level of intraspecific cocoon-type polymorphism. We compared the cocoons of Hyalophora species found throughout North America and investigated the evolution of architectural variation. We first characterized and compared the architectural features of cocoons at all three cocoon sections (outer envelope, inner envelope, and the intermediate section that separates them), and found that variation in the outer envelope underlies the differences in architecture between cocoons. Phylogenetic analysis indicates ancestral polymorphic architecture (both "baggy" and "compact" morphs), with diversification within Hyalophora for both monomorphic "compact" cocoons, and increased intermediate space and silk in "baggy" lineages. The evolution of these traits suggests a potential functional role for the different cocoon architectural forms.


Assuntos
Bombyx/fisiologia , Lepidópteros/fisiologia , Animais , Bombyx/genética , Lepidópteros/genética , América do Norte , Filogenia , Pupa/genética , Pupa/fisiologia
18.
Chemosphere ; 251: 126438, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32169693

RESUMO

Bombyx mori is an important economic insect. However, the environmental pollution caused by the widespread use of neonicotinoid insecticides has significantly affected the safe production of sericulture. In this paper, we determined the LC50 of acetamiprid, a kind of neonicotinoid insecticides, to 5th instar silkworm larvae, examined its residues in hemolymph and midgut of silkworm after continuous exposure to low-dose of acetamiprid, and investigated the transcription level of detoxifying-related genes and the activity of detoxifying enzymes. The results showed that acetamiprid was highly toxic (24-h LC50, 1.50 mg/L) to silkworm larvae. After continuous exposure to low-dose of acetamiprid (0.15 mg/L), the acetamiprid residue concentrations in hemolymph and midgut were 0.90 and 0.58 µg/mg, respectively, at 48 h, but all decreased at 96 h. At 24 h of acetamiprid exposure, the transcription levels of CYP4M5 and CYP6AB4 and the P450 enzyme activity were significantly enhanced. However, the transcription levels of CarE and CarE-11 and the activity of CarE enzymes were both inhibited by acetamiprid exposure. After 24 h-72 h of acetamiprid exposure, the transcription levels of GSTe3 and GSTd1 were significantly up-regulated, and the GST enzyme activity was also significantly elevated from 48 h to 96 h. Furthermore, the expression levels of FoxO, CncC and Keap1, the key upstream genes of detoxification enzymes, showed a similar trend as the GST genes. These results indicated that acetamiprid was reduced in midgut and the expression of GSTs was upregulated may via FoxO/CncC/Keap1 signaling pathway, which plays a key role in detoxification responses.


Assuntos
Bombyx/fisiologia , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Animais , Bombyx/enzimologia , Bombyx/metabolismo , Sistema Digestório/metabolismo , Inativação Metabólica , Proteína 1 Associada a ECH Semelhante a Kelch , Larva/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais
19.
Arch Insect Biochem Physiol ; 104(1): e21664, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32091635

RESUMO

The high-temperature stress gene GrpE plays an important role in coping with high-temperature stress. The mutation of key sites of this gene can improve the high-temperature resistance of organisms. In the present study, using complementary DNAs from the silkworm fat body as the template, the open reading frame sequence of the GrpE gene (BmGrpE) was amplified and was found to be 644 bp in length and encode a protein with a predicted molecular weight of 24.1 kDa. The presence of a binding site for the heat shock transcription factor (Hsf1) at -1440 bp upstream of its coding region indicates that BmGrpE may respond to high-temperature stress. BmGrpE was constitutively expressed throughout developmental stages, with the highest level observed in the 5th instar larvae stage. Moreover, in 5th instar larvae (the 3th day), BmGrpE was expressed in all tissues examined, with the highest levels in the fat body, silk gland, and midgut. Interestingly, under high-temperature stress, TiO2 nanoparticle treatment increased the messenger RNA levels of BmGrpE in the fat body and silk gland. After treatment with dsRNA of BmGrpE, the cell viability of BmN cells was significantly decreased under 34°C and H2 O2 stress (p < .05). Mutation of BmGrpE (H163L) enhanced the resistance of BmN cells under high-temperature stress. These results provide new clues for the study of molecular mechanisms of insect resistance to high temperatures.


Assuntos
Bombyx/genética , Temperatura Alta , Estresse Fisiológico/genética , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/metabolismo , Bombyx/fisiologia , Linhagem Celular , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Nanopartículas Metálicas , Mutação , Fases de Leitura Aberta , Interferência de RNA , RNA Mensageiro/metabolismo , Análise de Sequência de DNA , Titânio
20.
PLoS One ; 15(2): e0228453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074121

RESUMO

The late 5th instar caterpillar of the cecropia silk moth (Hyalophora cecropia) spins a silken cocoon with a distinct, multilayered architecture. The cocoon construction program, first described by the seminal work of Van der Kloot and Williams, consists of a highly ordered sequence of events. We perform behavioral experiments to re-evaluate the original cecropia work, which hypothesized that the length of silk that passes through the spinneret controls the orderly execution of each of the discrete events of cocoon spinning. We confirm and extend by three-dimensional scanning and quantitative measurements of silk weights that if cocoon construction is interrupted, upon re-spinning, the caterpillar continues the cocoon program from where it left off. We also confirm and extend by quantitative measurements of silk weights that cecropia caterpillars will not bypass any of the sections of the cocoon during the construction process, even if presented with a pre-spun section of a cocoon spun by another caterpillar. Blocking silk output inhibits caterpillars from performing normal spinning behaviors used for cocoon construction. Surprisingly, unblocking silk output 24-hr later did not restart the cocoon construction program, suggesting the involvement of a temporally-defined interval timer. We confirm with surgical reductions of the silk glands that it is the length of silk itself that matters, rather than the total amount of silk extracted by individuals. We used scanning electron microscopy to directly show that either mono- or dual-filament silk (i.e., equal silk lengths but which vary in their total amount of silk extracted) can be used to construct equivalent cocoons of normal size and that contain the relevant layers. We propose that our findings, taken together with the results of prior studies, strongly support the hypothesis that the caterpillar uses a silk "odometer" to measure the length of silk extracted during cocoon construction but does so in a temporally regulated manner. We further postulate that our examination of the anatomy of the silk spinning apparatus and ablating spinneret sensory output provides evidence that silk length measurement occurs upstream of output from the spinneret.


Assuntos
Comportamento Animal/fisiologia , Retroalimentação Sensorial/fisiologia , Manduca/fisiologia , Metamorfose Biológica/fisiologia , Seda/metabolismo , Animais , Ciências Biocomportamentais , Bombyx/anatomia & histologia , Bombyx/fisiologia , Manduca/anatomia & histologia , Microscopia Eletrônica de Varredura , Pupa/fisiologia , Sensação/fisiologia , Seda/análise , Seda/química
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