Project description:The silkworm, Bombyx mori, is a complete metamorphosis insect and an economically important for silk production, the model to study insect physiology and biochemistry. Bombyx mori nucleopolyhedrovirus (BmNPV) is a principal pathogen of the silkworm and its host range is restricted to silkworm larvae, requiring interaction with silkworm larvae to accomplish virus replication. Prothoracic glands (PGs) are a model for synthetic ecdysone with regulating insect growth and development. In this study, day-4 fifth instar silkworm larvae were infected by BmNPV, the wandering silkworms appeared in the infected groups were 12 hours earlier than that in the control groups, and the ecdysone titer in infected larvae was significantly higher than that of the control larvae. Then, we used RNA sequencing (RNA-seq) to analyze silkworm PGs 48 h after BmNPV infection. The classifications of the 15 differential expression genes (DEGs) were mainly involved in the metabolic processes and pathways. The RT-qPCR results of the DEGs in the PGs of BmNPV-infected at 24, 48, and 72 h were generally consistent with the transcriptome data. The transcripts of BmTrypsin-1 and BmACSS3 were significantly increased from 24 to 72 h after BmNPV infection that they may be involved in the maturation process in the latter half of silkworm fifth instar larvae. These findings will help to address the interactions between BmNPV infection and host developmental response.
Project description:Silkworms show a reproductive behavior induced by sex pheromone. To elucidate the neral mechanism of sex pheromone induced sexual behavior in the silkworm, we attempted to use the neural activity-induced gene as a neural activity marker. Since no neural activity-induced gene was identified in the silkworm, we conducted screening of neural activity-induced gene using the male silkworm brain. By the screening, we identified Bhr38 as a novel neural activity-induced gene, and succeded to comprehensively map the active neruons in the silkworm brain in response to the sex pheromone exposure. Further, we found that Dhr38, the Drosophila homologue of Bhr38, also expressed in a neural activity dependent manner. These results strongly suggest that Hr38 is a highly conserved neural activity-induced gene.
Project description:Background: MicroRNA (miRNA) and other small regulatory RNAs contribute to the modulation of a large number of cellular processes. We sequenced three total RNA libraries prepared from the whole body, and the anterior and posterior silk glands of Bombyx mori, with a view to expanding the repertoire of silkworm miRNAs and exploring transcriptional differences in miRNAs between segments of the silk gland. Results: With the aid of large-scale Solexa sequencing technology, we validated 244 unique miRNA genes, including 191 novel and 53 previously reported genes, corresponding to 309 loci in the silkworm genome. Interestingly, 24 unique miRNAs were widely conserved from invertebrates to vertebrates; 12 unique ones were limited to invertebrates and 33 were confined to insects; whereas the majority of the newly identified miRNAs were silkworm-specific. We identified 21 clusters and 42 paralogs of miRNAs in the silkworm genome. However, sequence tags showed that paralogs or clusters are not prerequisites for coordinated transcription and accumulation. The majority of silkworm-specific miRNAs are located in transposable elements, and display significant differences in abundance between the anterior and posterior silk glands. Conclusions: Conservative analysis revealed that miRNAs serve as phylogenetic markers and function in evolutionary signaling. The newly identified miRNAs greatly enriched the repertoire of insect miRNAs, and provide insights into miRNA evolution, biogenesis, and expression in insects. The differential expression of miRNAs in the anterior and posterior silk glands supports their involvement as new layers in the regulation of the silkworm silk gland.
Project description:Background: MicroRNA (miRNA) and other small regulatory RNAs contribute to the modulation of a large number of cellular processes. We sequenced three total RNA libraries prepared from the whole body, and the anterior and posterior silk glands of Bombyx mori, with a view to expanding the repertoire of silkworm miRNAs and exploring transcriptional differences in miRNAs between segments of the silk gland. Results: With the aid of large-scale Solexa sequencing technology, we validated 244 unique miRNA genes, including 191 novel and 53 previously reported genes, corresponding to 309 loci in the silkworm genome. Interestingly, 24 unique miRNAs were widely conserved from invertebrates to vertebrates; 12 unique ones were limited to invertebrates and 33 were confined to insects; whereas the majority of the newly identified miRNAs were silkworm-specific. We identified 21 clusters and 42 paralogs of miRNAs in the silkworm genome. However, sequence tags showed that paralogs or clusters are not prerequisites for coordinated transcription and accumulation. The majority of silkworm-specific miRNAs are located in transposable elements, and display significant differences in abundance between the anterior and posterior silk glands. Conclusions: Conservative analysis revealed that miRNAs serve as phylogenetic markers and function in evolutionary signaling. The newly identified miRNAs greatly enriched the repertoire of insect miRNAs, and provide insights into miRNA evolution, biogenesis, and expression in insects. The differential expression of miRNAs in the anterior and posterior silk glands supports their involvement as new layers in the regulation of the silkworm silk gland. Sequencing three total RNA pools of the whole silkworm body from 5th-instar day-3 larvae, and anterior and posterior silkworm silk glands, using the latest sequencing Solexa technology
Project description:Silkworms show a reproductive behavior induced by sex pheromone. To elucidate the neral mechanism of sex pheromone induced sexual behavior in the silkworm, we attempted to use the neural activity-induced gene as a neural activity marker. Since no neural activity-induced gene was identified in the silkworm, we conducted screening of neural activity-induced gene using the male silkworm brain. By the screening, we identified Bhr38 as a novel neural activity-induced gene, and succeded to comprehensively map the active neruons in the silkworm brain in response to the sex pheromone exposure. Further, we found that Dhr38, the Drosophila homologue of Bhr38, also expressed in a neural activity dependent manner. These results strongly suggest that Hr38 is a highly conserved neural activity-induced gene. The male silkworms were exposed to the female odor for 30 min (group P). Non-treated male silkworms were used as the control group group C. Ten brains were collected for each sample and stored at -80°C until use. Total RNA was isolated by the TRIzol reagent and subjected to microarray experiments using the custam made (8x16k) Oligo Microarray (Agilent Technologies, Inc.).
Project description:We identified genes regulated by parasitization of the silkworm Bombyx mori by three tachinid parasitoid species, Exorista japonica, Drino inconspicuoides and Pales pavida, using oligonucleotide microarrays. The numbers of genes and their intensity of expression varied with the species of parasitoid, within silkworm hemocytes and fat body.
Project description:Microsporidia have attracted much attention because they infect a variety of species ranging from protists to mammals, including immunocompromised patients with AIDS or cancer. Aside from the study on Nosema ceranae, few works have focused on elucidating the mechanism in host response to microsporidia infection. Nosema bombycis is a pathogen of silkworm pM-CM-)brine that causes great economic losses to the silkworm industry. Detailed understanding of the host (Bombyx mori) response to infection by N. bombycis is helpful for prevention of this disease. The 23 K silkworm genome array was used to investigate host responses (i.e., Bombyx mori) occurring at 2, 4, 6 and 8 d post-infection by Nosema bombycis.We focused on elucidating the mechanism of the host response to microsporidia infection, especially for the investigation of host immune response . The third instar molted silkworm larvae were in oral infected by Nosema bombycis. In order to known the silkworm host response to Nosema bombycis infection at different time points, samples of infected larvae (i.e., the treatment set) and uninfected larvae (i.e., the control set) were collected at 2, 4, 6 and 8 dpi for RNA extraction and array hybridization. The obtained data were usd to investigate on the interplay of the genome-wide expression profile of hosts.
Project description:With an experimental RNomics, we identified 194 novel ncRNAs in silkworm through four developmental stages (egg, larva, pupa and adult). Oligos of 132 ncRNAs were sucessfully designed, the expression of these ncRNAs were analyzed by dual-channel microarray, results showed that 36 ncRNAs had significantly differential expression during development.
Project description:Microsporidia have attracted much attention because they infect a variety of species ranging from protists to mammals, including immunocompromised patients with AIDS or cancer. Aside from the study on Nosema ceranae, few works have focused on elucidating the mechanism in host response to microsporidia infection. Nosema bombycis is a pathogen of silkworm pébrine that causes great economic losses to the silkworm industry. Detailed understanding of the host (Bombyx mori) response to infection by N. bombycis is helpful for prevention of this disease. The 23 K silkworm genome array was used to investigate host responses (i.e., Bombyx mori) occurring at 2, 4, 6 and 8 d post-infection by Nosema bombycis.We focused on elucidating the mechanism of the host response to microsporidia infection, especially for the investigation of host immune response .