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At least 775 records · Page 43Linked to original sources
PubMed1980

[Metabolism of 14C-soluble proteins from silkworm tissues during silk formation].

The functional role of individual labelled fractions of haemolymph, fat body, carcass, gut and anterior and posterior divisions of the silk gland of the silkworm Bombyx mori was studied, using polyacrylamide gel electrophoresis. It was found that the protein fractions with Rf = 0.02, 0.05, 0.09 and 0.24 are formed in the gut, carcass and fat body during active feeding and are utilized by the silk gland in the spinning period by means of haemolymph. The contents of amino acids in several electrophoretic protein patterns (Rf = 0.02, 0.05, 0.09 and 0.24) in the haemolymph were determined. These protein fractions are sources of nitrogen-containing material used for increasing the level of free amino acids in the silk gland and for biosynthesis of major silk amino acids.

Adipose Tissue↗
PubMed1980

Blastoderm formation in the silkworm egg (Bombyx mori L).

Embryogenesis in the egg of the silkworm. Bombyx mori, up to 24 h after oviposition was studied by light microscopy with special reference to nuclear migration and blastoderm formation. In Bombyx eggs blastoderm cells seem to form in a mechanism different from that usually seen in many other insect species; that is, in Bombyx eggs no typical cleavage furrows were seen. Cleavage nuclei which had migrated, accompanied by the associated cytoplasm, to the egg surface pushed up the plasma membrane and protruded beyond the initial level of the periplasm. The periplasm fused with their associated cytoplasm was partitioned among the pulled around the nuclei. Then each nucleus was separated by a laterally-invading limiting membrane from the yolk-granules-occupied region to yield a blastoderm cell.

Animals↗
PubMed1981

[Use of the leaves of the dandelion (Taraxacum officinale L.) in the feeding of the silkworm Bombyx mori L].

Experiments were carried out with eggs of Bombyx mori of the J--124xC--122 hybrid, imported from Japan. Tested was the feeding of the silkworm moth on leaves of dandelion (Taraxacum officinale L.) up to the end of the III instar. Feeding was also carried out with dandelion leaves up to the end of the IV instar, which, immediately prior to offering to the moths were sprinkled with water solutions of flurazolidon, 1.5 per cent, chloramphenicol with propylen glycol (5%)--50 cm3 each/1 of water or nalidixic acid, 2.5 per cent. The effect was studied of the antibacterial preparations applied to every kind of feed on the amount of microflora in the alimentary tract. It was found that moths given dandelion leaves reached the III instar, however, there was a very early manifestation of spontaneous nuclear polyhedrosis and bacterial infections of the alimentary tract. The addition of antibacterial preparations reduced the outbreaks of the two diseases and the microflora in silkmoths. Discussed is the possibility of the wide use of broad-spectrum antibacterial drugs in the prevention of these diseases.

Animal Diseases↗
PubMed1980

Large-scale purification of prothoracicotropic hormone of the silkworm (Bombyx mori).

Prothoracicotropic hormone has been successfully extracted from as many as 2,800,000 silkworm male adult heads and purified partially through an 8-step procedure. Approximately 7 microgram of the crude preparation ("crude PTTH") shows activity in the debrained Samia pupa test. A further 4-step chromatographic purification of the "crude PTTH" derived from 100,000 Bombyx heads yields 3.4 mg of purified preparation ("highly purified PTTH"), of which 7 ng causes adult development in a debrained Samia pupa.

Animals↗
PubMed1995

Interaction of silkworm larvae expressed monomeric hM-CSF with its receptor on murine bone marrow derived macrophage.

Human macrophage colony-stimulating factor (hM-CSF) expressed in the silkworm larvae was monomeric. The nature of the interaction of iodinated monomeric M-CSF with murine bone marrow derived macrophage (BMM) was studied. On incubation with 2 nM [125I]M-CSF at 4 degrees C, approximately 90% of the maximal binding occurred within 15 min with a plateau around 1hr which then gradually declined. Scatchard plot analysis showed that the Kd for the monomeric M-CSF is 5.3 x 10(-10) M and the number of binding sites per cell is 4 x 10(4). Competition experiment indicated that cellular binding of the iodinated monomeric rhM-CSF was almost as effective as the native M-CSF. The results show that the interchain disulfide bond of M-CSF is not essential for the natural folding of active M-CSF.

Animals↗
PubMed1975

[Vitellogenic protein in a male environment in the silkworm, Bombyx mori L. (Lepidoptera): attempts to obtain experimentally a normal vitellus].

An ovary, implanted in a male silkworm of the same age shows an abnormal vitellus, deprived of the principal vitello-protein. The amino-acid retention due to the removal of sericiglands does not lead to a normal vitellogenesis. On the contrary, the injection of an eggs extract allows the formation of eggs with a normal vitellus. Without this process, in male hemolymph, the vitello-protein did not reach the threshold necessary to be absorbed by the ovary.

Amino Acids↗
PubMed1977

[Studies on protein biosynthesis in the silk gland of Bombyx mori L. silkworm].

The incorporation of (14C) lysine (to characterize the biosynthesis of cellular proteins) and (14C) glycine (for silk fibroin) in free and membrane-bound polyribosomes was studied in fibroin portion of the silk gland of Bombyx mori silkworm in the V instar. It was shown that although the membrane-bound polyribosomes are found in posterior silk gland from the beginning of the V instar, the fibroin biosynthesis in the membranebound polyribosomes takes place predominantly in the second part of the V instar. On the other hand the cellular proteins are synthesized mostly in the free polyribosomes in the first half of the V instar. In the second half of the V instar in the sucrose gradient zone corresponding to free polyribosomes, monoribosomes unable to synthesize protein for the absence of mRNA are present. Nevertheless, these ribosomes isolated from the fibroin part of the silk gland in the end of the V instar do synthesize polyphenylalanine in the presence of poly (U), and aminoacyl-t-RNA-synthetases and tRNA's obtained from the posterior silk gland.

Amino Acyl-tRNA Synthetases↗
PubMed1995

Production of recombinant hantavirus nucleocapsid protein expressed in silkworm larvae and its use as a diagnostic antigen in detecting antibodies in serum from infected rats.

The recombinant nucleocapsid protein (rNP) of Hantaan virus was expressed by a baculovirus vector in silkworm hemolymph and was used as an antigen in western blotting (WB). The rNP is expressed in insoluble form in hemolymph; therefore simple washing of the insoluble fraction with phosphate-buffered saline by low-speed centrifugation allowed preparation of purified antigen for WB. The rNP had strain-specific and hantavirus-common epitopes similar to the authentic NP antigen of hantavirus and was stable after transfer to membrane. For detection of antibody in serially obtained sera from experimentally infected rats, WB enabled detection of IgM antibodies 3 days after infection, which was at least 2 days earlier than detection by the indirect immunofluorescent antibody test (IFA). Thus WB had a higher sensitivity than the IFA for detection of hantavirus antibody in the serum of experimentally infected rats. The WB-determined IgG antibody titer was about 10 times higher than that determined by the IFA. No background staining was observed by WB even at a 1:10 dilution of serum. The selected rat sera with strong background staining or confusing staining patterns by IFA, but not focus reduction neutralization test titers, could be interpreted as test-negative because they did not have a specific reaction to virus antigen by WB. Thus the specificity of WB was higher than that of the IFA. Moreover, WB can distinguish specific from nonspecific reactions by the detection of the specific antigen on the WB membrane. Therefore the IFA or enzyme-linked immunosorbent assay followed by WB is recommended for serologic confirmation of hantavirus infection.

Animals↗
PubMed1977

[Long-term reproduction of triploid and tetraploid parthenogenetic clones of silkworms during artificial thermal parthenogenesis].

The triploid and tetraploid clones of the silkworm (Bombux mori L.) are capable to be reproduced for a long time by means of thermal parthenogenesis. The activated eggs are pigmented in 80-99%. The hatching of larvae in triploid clones amounts to 20% and in tetraploid ones to 25-30%. The pigmentation of eggs and hatching of larvae greatly vary in different years: 47 to 100% and 0 to 73%, resp. In this respect, the polyploid clones are similar to those diploid ones which are characterized by the low percentage of complete parthenogenesis. The causes for the variability of parthenogenesis indices in the polyploid clones are discussed.

Bombyx↗
PubMed1995

[Cloning of the diapause hormone gene of the silkworm (Bombyx mori)].

A silkworm genomic library was screened with radiolabelled cDNA of Bombyx mori diapause hormone (Bom DH). Three positive clones were isolated from approximately 4 x 10(5) plaques, and subjected to further analyses. The DNA inserts excised from positive clones with SalI were ligated into pBluescript KS(+) vector and grown in E. coli XL1 cells. The DNA fragments obtained by EcoRI digest form the insert were subcloned into the same vectors. The nucleotide sequence analysis showed that these clones involved the Bom DH gene. Genomic Southern analysis suggested that the Bom DH is encoded by a single gene. The present study which is the first one on cloning of the Bom DH gene.

Animals↗
PubMed1997

Effect of silkworm hemolymph on the expression of E. coli beta-galactosidase in insect cell lines infected with recombinant baculoviruses.

The effects of silkworm hemolymph on the expression of foreign genes by recombinant baculoviruses in cell lines were studied. The expression efficiency of beta-galactosidase by recombinant virus containing the E. coli lacZ gene at various concentrations of hemolymph and FBS was determined in BmN and Sf cell lines. The addition of hemolymph to the medium containing FBS accelerated the expression of beta-galactosidase by recombinant viruses in both cells. It was more effective in BmN cells than in Sf cells. Hemolymph was most effective in enhancing virus multiplicity under conditions of 5% FBS.

Animals↗
PubMed1997

[Primary and secondary structure of 3'--end of the large subunit ribosomal RNA of silkworm Attacus ricini and evolution implications as inferred from the gene sequence].

The DNA sequence of the 3'-end of LSu-rRNA coding region of silkworm Attacus ricini was determined. By comparisons with the corresponding sequence of H. sapiens, X. leavis, H. momus, A. albopictus, D. melanogaster, C. elegants, S. pombe, M. musculus and M. racemosus, we found that the coding sequence we obtained is very conserved. Phylogenetic tree inferred by Neighbor-joining Method showed that the rate of evolution of insects was much faster than vertebrate. In addition, the secondary structure has also worked out it is highly conserved.

Animals↗
PubMed1997

Protein A linked latex antisera test for detection of infectious flacherie of silkworm, Bombyx mori L. caused by B. mori infectious flacherie virus.

Protein A linked latex antisera (PALLAS) test was used for detection of B. mori infectious flacherie virus (BmIFV) in silkworms. The test was found superior to direct latex agglutination (DLA) test for detection of BmIFV in infected larval and faecal matter extracts and purified preparations. Latex beads sensitized with anti-BmIFV IgG were able to detect up to 75 ng/ml BmIFV in PALLAS test and 300 ng/ml in DLA test. BmIFV was detected in diluted extracts of infected larvae (up to 1:200) and their faecal matter (up to 1:500). BmIFV progressive infection was detected at 12 and 24 hr of post infection in PALLAS and DLA tests, respectively in both larval and faecal matter extracts. PALLAS tests provides a simple, specific and highly sensitive test for detection of infectious flacherie virus.

Animals↗
PubMed1976

Morphogenesis of the silkworm egg.

Ovarian follicle development, which accompanies morphogenesis of the silkworm egg has three distinct phases: spheric, ellipsoidal and flattened-ellipsoid. Transitions between phases are rapid and form-stability (characterized by length/width ratio) is preserved from the beginning of the ellipsoidal phase. The geometric stability of the follicle-oocyte-ovariole system, the polarity of the egg and the determinism in form changes reveal strikingly coordinated spatial and temporal organization.

Animals↗