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At least 991 records · Page 55Linked to original sources
PubMed1991

Cloning and sequence analysis of membrane-bound alkaline phosphatase cDNA of the silkworm, Bombyx mori.

The nucleotide sequence (1974 bp) of cDNA coding for membrane-bound alkaline phosphatases (m-ALP) of Bombyx mori was isolated. The cDNA clone contained an open reading frame encoding a polypeptide (547 amino acids), which contains a hydrophobic signal peptide of 36 amino acids and the mature protein of 511 amino acids (Mr = 56,163). We found a highly hydrophobic domain presumed to be a membrane anchoring region at the C-terminus. Comparing analysis between Bombyx m-ALP and mammalian and Escherichia coli ALPs suggested an evolutionary relationship of sharing a common ancestral gene.

Alkaline Phosphatase↗
PubMed1992

Isolation and partial characterization of binding proteins for immobilized delta endotoxin from solubilized brush border membrane vesicles of the silkworm, Bombyx mori, and the common cutworm, Spodoptera litura.

1. Brush border membrane vesicles (BBMV) were prepared from the Bombyx mori, and Spodoptera litura, midguts. BBMV was solubilized. 2. Activated delta endotoxin from Bacillus thuringiensis were immobilized. 3. Solubilized BBMV proteins were applied to the toxin column and the proteins bound were analyzed by SDS-PAGE. 4. In the case of B. mori M(r) = 220,000, 150,000 and 130,000 and in the case of S. litura 160,000 bands were detected. 5. The bindings were inhibited by N-acetyl galactosamine and mannose. 6. The binding proteins applied onto a Con A column and eluted by 0.1 M methyl-alpha-glucose, suggesting that hybrid type sugar sidechain may involve in the interaction.

Animals↗
PubMed1994

Purification and characterization of a juvenile hormone binding protein from hemolymph of the silkworm, Bombyx mori.

A juvenile hormone binding protein (JHBP) has been isolated from Bombyx mori hemolymph by gel filtration, ion-exchange chromatography, chromatofocusing and hydroxyapatite column chromatography. Gel electrophoresis indicates that the isolated protein is homogeneous in the presence or absence of a denaturing agent. The JHBP in question has a relative molecular mass of 32 kDa, determined by denaturing gel electrophoresis. Chromatofocusing analysis indicated that the JHBP is an acidic protein with pI 4.9. The protein exhibits a dissociation constant of 9.0 x 10(-8) M for JH I, 1.14 x 10(-7) M for JH II and 3.9 x 10(-7) M for JH III, and thus its affinity for JH analogues is in the order of JH I > JH II > JH III. Its amino acid composition indicates that the protein consists of 297 residues of 18 kinds of amino acids. The sequence of the N-terminus of the polypeptide chain was determined for 34 of the first 36 residues: Asp-Gln-Asp-Ala-Leu-Leu- Lys-Pro-?-Lys-Leu-Gly-Asp-Met-Gln-Ser-Leu-Ser-Ser-Ala-Thr-Gln-Gln-Phe-Le u-Glu- Lys-Thr-Ser-Lys-Gly-Ile-Pro-?-Tyr-His-.

Amino Acid Sequence↗
PubMed1984

Sequence polymorphisms in the 5'-upstream region of the fibroin H-chain gene in the silkworm, Bombyx mori.

DNA fragments containing the fibroin H-chain gene from two different strains of Bombyx mori, J-139 and Nd (2) were cloned into phage lambda Charon 4A. Comparison of the restriction sites in these cloned DNAs revealed that in addition to the known polymorphism in the region coding for the repetitive amino acid sequence of the fibroin H-chain [Manning and Gage, J. Biol. Chem. 255 (1980) 9451-9457], at least two other types of polymorphism were present, one around the 5' end of the structural gene, and the other in the far upstream region of the gene. Restriction sites around the 5' end of the gene were well conserved between these strains, but some heterogeneity, suggesting the presence of small insertions, deletions or base changes, was noted. In contrast, DNA sequences of the region 2-4 kb upstream from the 5' end of the gene were markedly different between these two strains, indicating that either a deletion or an insertion of a DNA sequence longer than 2 kb had occurred in this region. Comparison with several other strains suggested that the observed changes in the far-upstream region were unique to the Nd(2) strain.

Animals↗
PubMed1995

Isolation and characterization of the lysozyme-encoding gene from the silkworm Bombyx mori.

We have isolated and characterized a Bombyx mori (Bm) cDNA encoding a lysozyme (Lyz). A 90-bp DNA fragment was amplified by PCR using degenerate oligodeoxyribonucleotide primers derived from the known amino acid (aa) sequence of the Bm Lyz. These PCR fragments were used to screen a fat body cDNA library. A clone containing the complete lys cDNA (1294 bp) was isolated and completely sequenced. The deduced 137-aa sequence showed high homology with other chicken-type Lyz. Bm lys gene expression was constitutive in fat body, cuticular epidermal tissue and at a very low level in hemocytes. This gene expression was up-regulated in fat body, hemocytes and cuticular epidermal tissue following the injection of Gram+ bacteria.

Amino Acid Sequence↗
PubMed1995

Structure of two cecropin B-encoding genes and bacteria-inducible DNA-binding proteins which bind to the 5'-upstream regulatory region in the silkworm, Bombyx mori.

Two genomic DNAs encoding cecropin B (CecB), an antibacterial protein from Bombyx mori, were cloned and sequenced. The number of CecB genes was estimated to be more than four copies per haploid by genomic Southern blotting. Two genes, CecB1 and CecB2, were located tandemly within 12 kb in the same orientation. These two genes encoded identical amino acids, though 15 nucleotides (nt) were different in the coding region and the intron size varied. About 90% of the nt spanning 800 bp in the 5'-untranslated region (UTR) were identical between the two genes. This 5'-flanking region contained characteristic sequences such as a repetitive element of B. mori (Bm1), an interleukin-6 response element (IL-6 RE), and two putative lipopolysaccharide (LPS) response elements (LPS RE). An electrophoretic mobility shift assay (EMSA) showed that the fat body contains at least three different nuclear proteins inducible by bacteria which bind to the 5'-UTR, suggesting that these proteins may be involved in CecB expression triggered by bacteria.

Amino Acid Sequence↗
PubMed1993

Expression and characterization of cDNAs for cecropin B, an antibacterial protein of the silkworm, Bombyx mori.

To analyze the induction mechanism of antibacterial protein gene expression, cDNAs coding for cecropin B have been cloned from the B. mori fat body cDNA library. Nucleotide sequences of two positive clones were determined and their amino acid sequences deduced. They revealed that these clones coded for the same cecropin, which is identical to purified cecropin B. However, the cDNAs contained different nucleotides at the third codon position and 5' or 3' non-coding regions. Results obtained by Northern blot analysis showed that the gene expression of B. mori cecropin B was rapidly induced by Escherichia coli and reached maximum levels 8 h after immunization. The expression of cecropin B gene occurred specifically in tissues, mainly in the fat body and hemocytes.

Amino Acid Sequence↗
PubMed1993

Induction of antibacterial protein synthesis by soluble peptidoglycan in isolated fat body from larvae of the silkworm, Bombyx mori.

Synthesis and secretion of bactericidal protein (cecropin) and lysozyme were induced by soluble peptidoglycan fragments (SPG) from Escherichia coli in a culture of fat body from Bombyx mori larvae. The rate of the secretion by fat body increased as a function of SPG concentration added to the culture medium. The induction of bactericidal activity was specific for peptidoglycan of a particular structure. Thus, SPG from Micrococcus luteus was 500-times less potent than E. coli SPG, and various glucans and peptides structurally related to peptidoglycan were all ineffective as elicitor. These results support the hypothesis that bacteria invading the haemocoel have to be partially degraded to generate peptidoglycan fragments as a signal molecule, which subsequently acts on a receptor on fat body cells and induces antibacterial protein synthesis.

Animals↗
PubMed1994

Purification and partial amino acid sequence of initiatorin, a prostatic endopeptidase of the silkworm, Bombyx mori.

We have purified initiatorin, a prostatic endopeptidase that initiates the protein-arginine degradation cascade in the spermatophore of Bombyx mori. Purification of the enzyme from spermatophores was monitored by measuring BAEE (N alpha-benzoyl-L-arginine-ethyl ester) hydrolyzing activity. Spermatophores were used as a source for this enzyme. Of several isoforms the major form (MW, 29 kDa) was purified over 200-fold. The N-terminal sequence of initiatorin showed strong homology with those of serine-type of endopeptidases.

Amino Acid Sequence↗