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At least 721 records · Page 40Linked to original sources
PubMed2005

Immunocytochemical identification of neuroactive substances in the antennal lobe of the male silkworm moth Bombyx mori.

As a first step towards understanding the functional role of neuroactive substances in the first olfactory center of the male silkworm moth Bombyx mori, we carried out an immunocytochemical identification of antennal lobe neurons. Antibodies against gamma-aminobutyric acid (GABA), FMRFamide, serotonin, tyramine and histamine were applied to detect their existence in the antennal lobe. In the present immunocytochemical study, we clarified four antenno-cerebral tracts from their origin and projection pathways to the protocerebrum, and revealed the following immunoreactive cellular organization in the antennal lobe. 1) Local interneurons with cell bodies in the lateral cell cluster showed GABA, FMRFamide and tyramine immunoreactivity. 2) Projection neurons passing through the middle antenno-cerebral tract with cell bodies in the lateral cell cluster showed GABA and FMRFamide immunoreactivity. Projection neurons passing through the outer antenno-cerebral tract with cell bodies in the lateral cell cluster showed FMRFamide immunoreactivity. 3) Centrifugal neurons passing through the inner antenno-cerebral tract b with cell bodies located outside the antennal lobe showed serotonin and tyramine immunoreactivity. Our results revealed basic distribution patterns of neuroactive substances in the antennal lobe and indicated that each projection pathway from the antennal lobe to the protocerebrum contains specific combination of neuroactive substances.

Animals↗
PubMed2005

Establishment of a sandwich ELISA system to detect diapause hormone, and developmental profile of hormone levels in egg and subesophageal ganglion of the silkworm, Bombyx mori.

In the silkworm Bombyx mori, diapause hormone (DH) is produced in the female subesophageal ganglion (SG) and induces embryonic diapause by targeting developing ovaries. DH is processed from a precursor protein consisting of DH, pheromone biosynthesis activating neuropeptide (PBAN) and three other neuropeptides (SGNPs). Because these five neuropeptides share a common sequence, FXPRLamide, at the C-terminus, a direct and specific assay for DH itself is required in order to understand the profile of concentration changes. In this study, we produced a mouse monoclonal antibody (anti-DH[N] mAb) against the N-terminal region of DH and developed a sandwich enzyme-linked immunosorbent assay using the anti-DH[N] mAb and a rabbit polyclonal antibody against the C-terminus of DH. This procedure enabled us to specifically quantify the DH molecule at femtomolar levels (equivalent to 1/10 of SG). We then plotted DH levels in eggs and SGs during embryonic and post-embryonic development. DH was present in late-stage embryos that had been destined for the production of both diapause and nondiapause eggs. DH levels in SG gradually increased in both types during larval development and peaked at the early pupal stage. At the middle pupal stage, DH levels in SG and SG-brain complex decreased markedly in the diapause-egg producing type, thus indicating active release of DH into the hemolymph. From 5th instar larva to adult, no sexual differences in DH levels were observed in SGs or SG-brain complexes from diapause and nondiapause egg-producing types.

Animals↗
PubMed2006

Apoptosis and adhesion of hemocytes during molting stage of silkworm, Bombyx mori.

To clarify the regulatory mechanism of the rapid changes in the hemocyte density in the silkworm, Bombyx mori, during ecdysis, we evaluated the relationship between the hemocyte density and the incidence of apoptosis during this stage. We also evaluated the role of the sugar chains on the adhesion of hemocytes by analyzing the effects on the hemocyte density of the injection of enzymes that cut sugar chains and monosaccharides into the body cavity. The hemocyte density was increased in the molting stage and spinning, and then decreased after the ecdysis. During spinning, the diameter of the granulocytes markedly increased, in which fatty granules in the cytoplasm increased, becoming foamy. They were identified to be apoptotic hemocytes using the Hoechst staining and the Comet assay. The decrease in the hemocyte density during spinning was mainly caused by the apoptosis of granulocytes. Next, we focused on the fluctuation of hemocyte density during the molting stage. Examination of the changes in the hemocyte density induced by injecting glycoside hydrolases, neuraminidase, sialic acid, or monosaccharides into the body cavity during the fourth molt stage and the third day in fifth instar larva demonstrated that the alteration of hemocyte density was regulated by the attachment and detachment of hemocytes via a selectin ligand, sugar chains. As with the injection of glycoside hydrolase, neuraminidase, sialic acid and fucose raised the hemocyte detachment, and it was assumed that the selectin ligands include the sialyl Lewis x like sugar chains, the same as mammalian lymphocytes.

Animals↗
PubMed2006

Gene expression profiling in the silkworm, Bombyx mori, during early embryonic development.

We prepared a cDNA library for a microarray from eggs of the silkworm, Bombyx mori, at the germ-band formation (24 hours after fertilization) stage. Using a microarray constructed with 2,445 ESTs, we screened gene expression profiles during germ-band formation at six specific time points in the early embryonic stages (from the unfertilized egg to the formation of abdominal leg appendages), and determined 241 of these cDNAs to represent genes that were expressed differentially during the germ-band formation stage. These differentially expressed genes grouped into two clusters. In the early and late clusters, 203 and 38 genes were upregulated, respectively. In the upregulated clusters, we isolated several genes that were associated with development and cell communication, including egalitarian, RAD23b, innexin 2, and senescence-associated protein. Northern blot hybridization revealed that the expression patterns of 14 genes had changed in each of the stages. In this study, we assessed changes in the levels of gene expression in relation to the germ-band formation stages in whole Bombyx embryos.

Animals↗
PubMed2006

A rapid increase in cAMP in response to 20-hydroxyecdysone in the anterior silk glands of the silkworm, Bombyx mori.

In the anterior silk glands (ASGs) of the silkworm, Bombyx mori, intracellular cAMP increases transiently to a very high level shortly after the hemolymph ecdysteroid peak in the prepupal period. In cultured ASGs obtained on the day of gut-purge, cAMP levels were increased by 20-hydroxyecdysone (20E), and this increase was enhanced by an inhibitor of phosphodiesterase, but was not affected by alpha-amanitin, indicating the 20E action may not be mediated via gene expression. The increase in cAMP occurred within 30 seconds of exposure to a physiological concentration of 20E (1 microM), and also by ponasterone A. Our findings indicate a nongenomic action of ecdysteroids in insects, which may be an additional mechanism by which this steroid hormone induces acute responses in tissues and cells.

Animals↗
PubMed2002

Production of recombinant human calcitonin from silkworm (B. mori) larvae infected by baculovirus.

A synthetic modified gene encoding the human calcitonin analog (hmCT) was expressed by use of the baculovirus expression system. After injection with recombinant baculoviruses, the hmCT-GST fusion protein was produced within the silkworm larvae. The fusion protein was purified by affinity chromatography. Biological activity of hmCT for hypercalcemic effect was determined in normal rats.

Animals↗
PubMed1978

Tissue specific glucose-trehalose variations during spinning in the eri-silkworm, (Philosamia ricini).

The beginning of spinning process in Eri-silkworm is characterized by sharp fall in the levels of glucose and trehalose in silkgland which gets completely decomposed after 6 days of spinning. Fatbody actively synthesizes trehalose during early days of spinning which results in enhanced level of this disaccharide in haemolymph. On the other hand, decreased glucose concentration of body fluid during early days of spinning is apparently because of its absorption by silkgland for its energetic needs.

Animals↗
PubMed1981

Soluble and particle-bound trehalase in the silk glands during larval-pupal development of the silkworm, Bombyx mori.

Trehalase localization in silk glands of the silkworm, Bombyx mori has been studied during larval-pupal development. Subcellular distribution of the silk gland trehalase depends upon larval-pupal development. The activity increases in the soluble fraction with a concomitant decrease in the particle-bound fraction during larval-pupal development. The pH-optimum value of trehalase activity in the particle-bound fraction changes from 6.5 to 6.0, and in the soluble fraction from 5.5 to 4.5 in the course of the silk gland degeneration during metamorphosis.

Animals↗
PubMed1984

Metabolic reorganization in the silk gland of eri-silkworm, Philosamia ricini, during thermal acclimation.

The silk gland of eri-silkworm, Philosamia ricini, at the end of the 5th instar, presents an interesting augmentation of RNA (23.5%) and protein (47.1%) concentrations in conjunction with a decrease in amino acid/DNA ratio (64.4%) due to the cold adaptation. However, on the first day of spinning process, the protein/DNA ratio of the tissue undergoes a decrease of 22.9% in its level, which has been attributed to the "masking" of the protein biosynthesis due to the commencement of spinning process.

Adaptation, Physiological↗
PubMed1996

Melanoxazal, new melanin biosynthesis inhibitor discovered by using the larval haemolymph of the silkworm, Bombyx mori. Production, isolation, structural elucidation, and biological properties.

A new melanin biosynthesis inhibitor, melanoxazal, was isolated from the fermentation broth of Trichoderma sp. ATF-451 by successive purification procedures of carbon adsorption, ethyl acetate extraction and silica gel column chromatography. The inhibitor possesses a novel oxazole-containing structure with molecular formula, C8H9NO3. The structure was determined by means of NMR analyses to be (E)-4-(2'-formyl-3'-hydroxybuten-1'-yl) oxazole, which is related to melanoxadin. Melanoxazal inhibited melanin formation in the larval haemolymph of the silkworm, Bombyx mori; IC50 value = 30.1 micrograms/ml. Melanoxazal also showed a strong inhibitory activity against mushroom tyrosinase with IC50 value = 4.2 micrograms/ml.

Animals↗
PubMed1999

Inducible gene expression of moricin, a unique antibacterial peptide from the silkworm (Bombyx mori).

Molecular cloning of cDNAs encoding moricin, a novel antibacterial peptide from the silkworm (Bombyx mori), was performed using a fat-body cDNA library. A reverse-transcription PCR product encoding a partial nucleotide sequence of moricin was used as a probe. Nucleotide sequencing of four positive clones revealed two types of moricin cDNAs designated moricin 1 and 2. cDNAs for moricin 1 and 2 shared 97.2% identity in their nucleotide sequences. Although one amino acid residue (Phe6) of moricin 1 in the putative signal peptide was replaced with Lys6 in moricin 2, amino acid sequences of their mature portions were identical. Moricin gene expression in B. mori larvae injected with Escherichia coli was observed in fat-bodies, haemocytes and the Malpighian tubule, but not in other tissues like the midgut and silk glands. Accumulation of moricin gene transcripts induced by E. coli reached a maximum level 8 h after injection and persisted up to 48 h. It was confirmed that lipopolysaccharide (LPS) and lipid A, which are cell-wall components of E. coli, triggered moricin gene expression. Comparison of gene expression between moricin 1 and 2 by PCR using specific primers indicated that moricin 2 gene was more strongly expressed than moricin 1 gene. A genomic clone encoding moricin 2 was screened from a B. mori genomic library using a moricin cDNA as a probe. Regulatory motifs for gene expression such as nuclear-factor-kappaB-binding-site-like sequence (kappaB site) and nuclear-factor-interleukin-6-binding-site-like sequence (NF-IL-6 site) were found in the 5'-upstream regulatory region. An electrophoretic-mobility-shift assay revealed that there are bacterial LPS-inducible nuclear proteins that can bind to the kappaB site and other sites in the regulatory region.

Amino Acid Sequence↗
PubMed2000

[High expression of human EPO gene in the larvae and pupae of the silkworm, Bombyx mori].

Erythropoietin (EPO) is a glycoprotein hormone produced primarily by the kidney, and is principal factor regulating red blood cell poduction. The synthesized EPO cDNA was inserted into the transfer vector pBlueBac III to generate the recombinant transfer plasmid pBlueBacEPO. Cotransfection of BmN cells with pBlueBacEPO DNA and Wild BmNPV DNA generated the recombinant virus rBmNPVEPO carrying EPO gene driven by the strong promoter of AcNPV polyhedrin gene. The results of Southern blot and PCR reaction confirmed that EPO gene had been correctly inserted in the target position in the BmNPV genome. ELISA assay showed that the EPO gene was expressed with high level in the larvae and pupae of the silkworm. The larvae and pupae produced as high as 62,800 u and 74,000 u in 1 mL hemolymph on the 4th day (larve) and the 5th day(pupae) after infection with the recombinant virus rBmNPVEPO, respectively. Western blot analysis showed the molecular weight of rhEPO produced in the lavae or pupae was about 26 kD. Biologic assay showed the rhEPO had high activity (about 63,000 u in per milliliter of hemolymph) in vitro.

Animals↗
PubMed1975

[Ultrastructure of the silkworm testis. II. Ductus deferens].

Ultrastructure of the silkworm's ducts defferens is described after spermatozoa went out of lobulli testis and after the end of secretion. D. defferens is composed of an external layer of the ring and longitudinal muscles and of an internal layer of glandular cells. Both layers are separated by structurless lamina--tunica propria. Z-discs of irregular form are placed at the borders of sarcomeres. M-lines are absent. Sarcolemma intrudes into the muscle fibers at the level of Z-discs and gives origin to T-system the tubes of which together with sarcoplasmic reticulum form dyades. Structures like intercalate discs are observed in muscle tissue at the level of Z-discs. Glandular cells have unusually developed nucleoli, many ribosomes, lysosome-like and residual bodies. There are comb desmosomes between the glandular cells.

Animals↗
PubMed2000

Effects of rhM-CSF expressed in silkworm on cytokine productions and membrane molecule expressions of human monocytes.

AIM: To study the effects of recombinant human macrophage colony-stimulating factor (rhM-CSF) expressed in silkworm on cytokine productions and membrane molecule expressions of monocytes. METHODS: The rhM-CSF was added to the human peripheral blood monocyte cultures and 3 d later, the culture supernatants and cells were collected, respectively. TNF-alpha, IL-6, IL-8, and IFN-alpha levels in the supernatants were detected by biological activity test or ELISA and expressions of CD11b, CD16, HLA I, and HLA II on the cellular surface were examined by the method of alkaline phosphatase anti-alkaline phosphatase complex (APAAP). RESULTS: The rhM-CSF promoted TNF-alpha, IL-6, and IL-8 inductions of monocytes and increased the percentages of CD11b, CD16, HLA I, and HLA II molecule expression on monocytes. CONCLUSION: The rhM-CSF plays a role in monocyte function up-regulation and has a certain practical value in immunological therapy.

Adult↗
PubMed2001

[Simultaneous expression of chicken anaemia virus proteins VP1 and VP2 in silkworms].

By cloning vp1 and vp2 genes of chicken anaemia virus into transfer vector pBacPAK8, recombinant transfer plasmids pBac-vp1 and pBac-vp2 were obtained. Then BmN cells were co-transfected with linearized baculovirus Bm-BacPAK6 DNA and above two recombinant plasmids respectively, recombinant viruses Bm-vp1 and Bm-vp2 were constructed and used to co-infect silkworms to express recombinant proteins. The results indicated that recombinant VP1 and VP2 could induce the corresponding antibody in chickens using immunofluorescence assay and the expression products could protect filial generation from the attack of CAV. Recombinant BmNPV expressing VP1 and VP2 is, therefore, a great hopeful production system for a subunit vaccine against CAV infection.

Animals↗
PubMed1975

Number of cells in diapausing silkworm embryos with different ploidies.

The number of cells in diapausing silkworm embryos of different ploidies was determined. Thermal activation was shown to lead to a decrease in the number of cells in parthenogenetic embryos in comparison with normal, zygotic development. The number of cells in the embryo is a direct function of egg volume and a reciprocal function of embryo ploidy and is affected by the maternal genotype.

Animals↗
PubMed2001

Regulation of Gene Expression by SAR of Silkworm Attacus ricini rRNA Gene.

The 1 kb scaffold-attachment region (SAR) at 5' non-transcription region of rRNA gene of silkworm Attacus ricini was cloned into eukaryotic expression vector pLu, which contained luciferase report gene and neo(R) selecting marker. After transfection of constructs into NIH3T3 cell line by using cation liposome, the luciferase activity was monitored to check the SAR's function. The results demonstrated that the SAR could enhance gene expression up to 15-fold in stable transformed cells, but no obvious gene expression was observed in transient transfection. Its effect on gene expression appeared to requirechromosomal integration. Southwestern blotting experiments showed that SAR specifically bound to nuclear matrix proteins of NIH3T3 cells. The binding with nuclear matrix may be necessary for SAR function of transcriptional enhancement.

Journal Article↗
PubMed1999

Expression of Nerve Growth Factor from Agkistrodon halys Pallas in Silkworm Larvae.

The cDNA encoding nerve growth factor (NGF) precursor from Agkistrodon halys Pallas (a Chinese snake species) was cloned into pBacPAK8 a baculovirus shuttle vector. The recombinant shuttle vector pBacPAK-NGF was coinfected with linear Bm-BacPAK6 DNA into BmN cells. The recombinant virus was screened and plaque-purified. The silkworm larvae were infected with the recombinant virus and collected 5 days later. The SDS-PAGE and the NGF activity by bioassay of PC12 cells have shown a high expression level of NGF of good biological activity in the larvae.

Journal Article↗