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At least 343 records · Page 19Linked to original sources
PubMed1997

Expression of the Arrowhead Proteinase Inhibitor B (API) Gene in the Silkworm Larvae and Pupae.

The arrowhead proteinase inhibitor B (API) gene was cloned into baculovirus transfer vectors of pBacPAK8 and pOSX, and two recombinant transfer vectors, pBacPAK (API) and pOSX (API), were constructed. Co-infection was accomplished with either one of the recombinant transfer vectors and Bm-BacPAK6 DNA in BmN cells. Then recombinant virus of CrBK9, CrBK10 and BX was selected. API gene was successfully expressed in silkworm larvae and pupae. The recombinant API (rAPI) showed strong inhibitive activity on bovine pancreas trypsin. The inhibiting activity of the expression product was 1.0x10(5) u/ml haemolymph for silkworm larvae and 1.3x10(5)u/ml haemolymph for pupae. In addition, SDS-PAGE of the preliminarily purified rAPI showed its molecular weight to be about 19 kD.

Journal Article↗
PubMed1996

The Recombination and Expression of a Chimeric Antibody Light Chain Gene in Cells of Silkworm Bombyx mori.

A chimeric immunoglobulin light chain gene had been expressed in a baculovirus expression system, which was achieved by infecting the silkworm cells with the recombinant virus r-NPVL2 containing the cDNA of immunoglobulin against a small cell lung cancer. PCR analysis and Southern hybridization proved that the antibody light chain cDNA hand been integrated into the modified BmNPV genome. Expression products of human-mouse chimeric antibody light chain in the silkworm cells were detected by both Western blot and ELISA.

Journal Article↗
PubMedDate not supplied

[Biosynthesis of recombinant human hepatitis B M-HBsAg in silkworm larvae].

The middle surface antigen (M-HBsAg) of human hepatitis B virus is virus envelope protein. It's used as a basis for development of vaccine and test-system for detecting of hepatitis B virus. The cDNA of M-HBsAg was inserted into transfer vector pBK273 under the polyhedron promoter with obtaining of recombinant plasmid DNA pBHep-2. As a result of cotransfection pBHep-2 with wild type BmNPV the recombinant baculovirus rBmNPVHep which included the cDNA of M-HBsAg under the polyhedron promoter was obtained. Infection of silkworm larvae Bombyx mori with recombinant virus resulted in expression of foreign gene and accumulation of middle surface antigen of human hepatitis B virus mostly (>90%) in fat bodies of silkworm larvae.

Animals↗
PubMed2004

[Construction of AFLP molecular markers linkage map and localization of green cocoon gene in silkworm (Bombyx mori)].

Based on an improved method of AFLP, AFLP markers were employed for construction of a linkage map and localization of Gc gene used a set of 44 backcross lines( BC1) of silkworm ( Bombyx mori) as a mapping population. In this work, all together 3 956 bands were obtained by 28 pairs of primers and 141.3 bands each primer pair on average. Among them 2 836 bands were in good agreement with the segregation pattern. A total of 1 018 (25.7%) polymorphic AFLP markers were detected. The 693 (68.1%) of polymorphic markers with 1:1 segregation ratio ( P < or = 0.05) were obtained. Furthermore,The analytical model was based on the backcross type and the parameters were set as following: LOD = 3.0, maximum recombination value of 0. 20 and use the command ' group', 'compare', 'try', 'map' and 'ripple' to construct the linkage maps. 407 of the 693 loci were chi2 tested in agreement with 1:1 segregation were divided into 33 linkages by Mapmaker/Exp(Version 3.0), with a total map distance of 3 676.7 cM and a mean distance of 9.1 cM between markers. The morphological gene Gc was located between L-P4T6-107 and L-PT6T4-84 on linkage group 22. In addition, 286 markers were not included in the linkage groups. The efficiency of loci mapping was 58.7%. Among the 33 linkage groups, the morphological marker Gc classically localized on linkage group 15 was relocated on linkage group 22 on the map, suggesting that this molecular linkage group corresponds to linkage group 15 on the linkage map based on morphological characters. All these have laid an important base for the marker assisted breeding of the silkworm.

Animals↗
PubMed2004

[The effect of heterosis on inheritance of quantitative traits in silkworm exposed to electromagnetic irradiation].

The effect of heterosis was studied in several quantitative traits of clone breed and interbreed silkworm hybrids exposed to electromagnetic irradiation (lambda = 1.6 cm, power density 700 microW/cm2) during postdiapause embryonic development. The influence of the type of reproduction on the manifestation of irradiation effects in the next generation was also examined. In hybrids, the resistance to low-intensity high-frequency irradiation was higher than in the parental forms. Unlike the latter, the hybrids showed no significant modification of the traits after the exposure to electromagnetic irradiation. In the second generation, the modifying effect of irradiation is retained in the case of parthenogenetic silkworm development but not after mating.

Animals↗
PubMed1997

[Recombinant human macrophage colony-stimulating factor expressed in silkworm accelerates hematopoietic recovery of radiolesion mice].

OBJECTIVE: To demonstrate the hematopoietic enhancement activity of recombinant human macrophage colony-stimulating factor (rhM-CSF). METHODS: Balb/c mice were sublethally irradiated with 60Co gamma-rays and then the rhM-CSF expressed in silkworm (10(3)U per individual for 7 days) was administered intraperitoneally. RESULTS: (1) The peripheral white blood cell counts of treatment group at day 15 and day 20 after irradiation were significantly higher than those of normal control group; (2) At days 10, 15, 20, 25 and 30 after irradiation, the difference between the peripheral monocyte counts of the treatment and control group were statistically significant; (3) At days 15, 20 and 25 after irradiation, the difference between the peripheral granulocyte counts of the two groups were also significant; (4) At day 9 after irradiation, the bone marrow CFU GM yield of the control group were significantly lower than those of the treatment group. CONCLUSION: rhM-CSF expressed in silkworm could accelerate hematopoietic recovery in irradiated mice.

Animals↗
PubMed2004

Molecular profiling of silkworm biodiversity in India.

Molecular tools opened a new vista to understand nature's bio-diversity and its relevance and the same approach was availed of to build-up the foundation work on the bio-diversity of silkworm spp in India. It is well established that the heritage of usage of silk for dress materials in India, Russia and China dates back to premedieval period and in spite of industrial development resulting to de-forestation, India still can claim as the owner of wide bio-diversity, espicially in northern India for silkworm spp. The molecular diversity was assessed among Antheraea mylitta, A. assama, A. pernyi, A. provlei, A. roylei and Philcosomia cynthia wiht 11 ISSR and 8 non-random primers on agarose gel. Nei's statistics as also Euclidean distance matrix was applied to find the genetic diversity between the six species, wherein the closest relationship between A. pernyi and A. proylei is established. With the help of POPGEN statistics, the average genetic heterozygosity appeared as 0.271 while Shanon's index is 0.4312 and alleles with segregation ratios of 3:1, 2:1, 1:1, 9:1 (generated with ISSR primers) were identified which can be utilized for future molecular breeding porgram. Further, and attempt was made to isolate a number of bands generated with 3 ISSR and six non-random primers, specific for different species and 22 such markers have been characterized through sequencing which will be made available through international public domain database.

Animals↗
PubMedDate not supplied

[Proteolytic enzymes as markers of productivity and heterosis of silkworm].

A positive correlation between the activity level of cysteine proteinases in developing eggs of common silkworm moth (Bombyx mori L.), on the one hand, and a set of commercial characteristics, on the other, was found. This allows the determination of cysteine proteinase activities (pH optima of 3.0, 3.6, and 8.6) to be recommended as a biochemical test for an early prediction of potential productivity of silkworm breeds. A positive correlation between the activity level of acid cysteine proteinases in eggs of parental breeds and a set of commercial characteristics of their hybrids was detected, indicating a principal possibility of predicting the degree of heterosis.

Animals↗
PubMed2002

[Sex control of silkworm by the interaction between gene and environment].

The silkworm embryo of the varieties, sBan, K05, Ban1, S1 and D05 was sensitive to the high temperature and low humidity incubating condition, while that of Nong4, Xinjiu and Xiankang was more endurable. By crossing the female Xinjiu with the male of sensitive varieties, such as sBaa, K05, Ban1, S1 or D05, their female progenies were sensitive to the high temperature and low humidity during incubation and could not hatch, while the males could hatch normally. Experiment showed that silkworm sex could be controlled by the interaction between gene and environment. The sensitive period was at late stage during the embryo development. The RAPD analysis showed that the similarity index of the five temperature-sensitive varieties of sBan, K05, Ban1, S1 and D05 was 63.04-76.47%.

English Abstract↗
PubMed2005

[Effect of white spot syndrome virus envelope protein Vp28 expressed in silkworm (Bombyx mori) pupae on disease resistence in Procambarus clarkii].

The vaccine made of recombinant envelope protein (rVp28) of white spot syndrome virus (WSSV) expressed in silkworm (Bombyx mori) pupae using a baculovirus vector was used to investigate the efficacy of oral administration on WSSV disease resistance of Procambarus clarkii. Vaccine was mixed with diet at a ratio of 2% (w/w), and Procambarus clarkii were orally administered throughout 75 days. Vaccination with rVP28 showed the significantly higher cumulative survival compared with positive and negative control (P < 0.05) following an oral challenge on the 35th day post-vaccination (dpv), with PRP values 54.16% and 59.26%, respectively. rVP28 induced higher resistance via IM (intramuscular) injection challenge with WSSV stock, with PRP value of 46.12% and 49.99%, respectively. The survivors were subsequently re-challenged on the 55th dpv. rVP28 induced the significantly higher resistance to oral re-challenge (P < 0.05), with both PRP values 55.80% and 63.16%, respectively. rVP28 induced higher resistance to IM injection re-challenge, with both PRP values 31.25%. A DIG labeled WSSV DNA probe was used to detect WSSV by in situ hybridization. The positive cells were observed in epithelial cells of stomach, hepatopancreas and gut of the infected control crayfish, while negative reaction were observed in the tissues of survivors-vaccinated. These results indicated that vaccination of crayfish with recombinant protein had significant effect on oral infection, and had higher resistance against intramuscular injection challenge. This suggested the protection against WSSV could be induced in crayfish by recombinant protein rVp28 expressed in silkworm pupae.

Animals↗
PubMed2005

[The expression of VP19 gene from prawn white spot syndrome virus in silkworm, Bombyx mori using host range-expanded HyNPV].

Prawn white spot syndrome is caused by the pathogen prawn white spot syndrome virus (WSSV). VP19 is a vesicle membrane protein of WSSV. HyNPV (Hybrid of AcNPV and BmNPV) constructed by the recombination of BmNPV and AcNPV is a new hybrid virus having both of their advantages. The recombinant transfer vector pBlueBicHisC-vp19 and recombinant baculovirus HyNPV-VP19 were constructed on the basis of the successful cloning of VP19. Newly-molted silkworms Bombyx mori of fifth instar were inoculated by the recombinant virus. SDS-PAGE and Western blotting analysis showed a specific band, about 21kD, which was consistent with the expectation suggesting that the WSSV-VP19 gene was successfully expressed in silkworm bodies.

Animals↗
PubMed1989

[The features of the 3' terminal sequences of the 18S rRNA gene from silkworm Attacus ricini].

The 3' terminal sequence of the gene for 18S rRNA of silkworm Attacus ricini have been sequenced. Comparison of this sequence with the 18S rDNA of silkworm Bombyx mori, Drosophila melanogaster, rat and the 16S rDNA of E. coli has shown that there is a remarkable homology between them. Moreover, the stem and loop formation of 3' regions of these rDNAs are very similar. There is a conservative EcoR1 site in the 3' region of these rDNAs. These results may contribute to the understanding of the functions of the 3' end of 18S rDNA in protein synthesis, in proceeding of rRNA precursor, and to the understanding of the evolutionary relation of rDNAs.

Animals↗
PubMed1975

RNA-polymerase activity in isolated nuclei of developing silkworm embryos.

Nuclei isolated from developing embryos of the silkworm (Bombyx mori) are capable of RNA synthesis in vitro. The incorporation of C-14-uridine triphosphate (C-14-UTP) into the acid-insoluble fraction requires the presence of the other three ribonucleoside triphosphates; it is inhibited by actinomycin, olivomycin, and ethidium bromide, and is stimulated by ammonium sulfate. In a medium of moderate ionic strength C-14-UTP incorporation is slightly inhibited by alpha-amanitine (4 mug/ml), whereas in the presence of 0.2 M ammonium sulfate the same alpha-amanitine concentration reduces the incorporation by 90%. These data indicate that silkworm embryo nuclei, like nuclei from several other sources, contain two different RNA-polymerase fractions.

Amanitins↗
PubMed1977

[Obtaining autosomal recessive mutations in the silkworm by exposure to nitrosomethylurea].

Mutagenic effect of N-nitrosomethyl urea (NMU) was studied in silkworm Bombyx mori L. Taking into consideration the specificity of the mutagen action, the main part of the work delt with the search for the optimum regime of the mutagen administration. The NMU effect is observed at different stages of the silkworm development by means of different methods. Maximal frequency of mutation in +re locus, obtained by the method of abdominal injection of the male-morth comprised 1.4%. Genetic analysis of the nature of the mutants obtained has revealed them to be point mutants.

Animals↗
PubMed1982

[Subcellular localization of some enzymes in silkworm eggs].

Differential centrifugation of the silkworm (Bombyx mori L.) egg homogenates resulted in nuclear, mitochondrial, lysosomal and cytosol infarctions, which were analyzed for the activities of alanine, aspartate- and tyrosine aminotransferases, 3-glycerophosphate- and lactate dehydrogenases and acid and alkaline DNAases. Alanine- and aspartate aminotransferases as well as 3-glycerophosphate dehydrogenase are localized mainly in the cytosol, where their activities made up to 86.2, 95.4 and 98.4% of their total activity, respectively. The activities of lactate dehydrogenase and acid DNAase are distributed between the nuclear and mitochondrial fractions; this distribution is even in the case of the former enzyme, whereas in the case of the latter the bulk (90.6%) of total enzyme activity is found in the nuclei. In contrast to the other enzymes whose activity is distributed between different cell fractions, tyrosine aminotransferase is localized exclusively in mitochondria, while alkaline DNAase--exclusively in the nuclei. No correlation between the level of enzyme specific activity and its total content in the fractions was established. The role of the enzymes under study in silkworm metabolism is discussed.

Animals↗
PubMed1995

Baculovirus mediated high-level expression of luciferase in silkworm cells and larvae.

Bombyx mori nuclear polyhedrosis virus (BmNPV)-based baculovirus expression system exploits silkworm larvae as an economical alternative to large-scale cell cultures for production of biomolecules. To generate recombinant BmNPV at high frequencies, we have achieved high efficiency transfection of B. mori cells, BmN, through lipofection. Optimal conditions for lipofection were standardized by quantification of the transient expression level of firefly luciferase (luc) reporter gene under control of an immediate early gene promoter of BmNPV. Lipofection was 50-fold and 100-fold more efficient than the calcium phosphate method for transfecting BmN and Sf9 cells, respectively. Lipofection enabled us to generate a recombinant BmNPV (vBmluc), harboring luc under control of the strong polyhedrin promoter. On infection with vBmluc, luciferase was expressed at very high levels, 170 micrograms/10(6) BmN cells or 13 mg/larva. Expression of luciferase in vBmluc-infected larvae was visualized by luminescence emission instantaneously following luciferin injection generating "glowing silkworms".

Animals↗
PubMed1995

Yeast-prepro-alpha-factor-leader-region-directed synthesis and secretion of truncated human macrophage colony-stimulating factor in the silkworm Bombyx mori.

Human macrophage colony-stimulating factor (hM-CSF) cDNA joined to the leader region of the precursor of the yeast mating pheromone alpha-factor (MF alpha L) was expressed at high levels in BmN cells and in silkworm (Bombyx mori) larvae, using recombinant Bombyx mori nuclear polyhedrosis virus, as a vector. The biological activity of rhM-CSF detected in the haemolymph was 1 x 10(6) colony-formation units/ml, approximately half of the expression level directed by the native signal peptide of hM-CSF in silkworm larvae. The secreted rhM-CSF was purified to homogeneity. N-terminal analysis showed that the signal peptide had been removed, indicating that insect cells possess the enzymic activity necessary to cleave the pro-alpha-factor leader region from the fusion protein at the carboxy side of Lys-Arg dibasic residues, which is the cleavage site recognized by KEX2 endopeptidase in yeast cells.

Amino Acid Sequence↗