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Publications (6)13.69 Total impact

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    ABSTRACT: A new family member of insect defensin, an antibacterial peptide, has been isolated from larvae of a beetle, Allomyrina dichotoma. The peptide consisted of 43 amino acids and 6 cystein residues were conserved in the same position as that of other insect defensins. The new defensin was found to be inducible by bacterial injection. Analysis of the antibacterial spectrum of A. dichotoma defensin indicated that this peptide showed antibacterial activity against Gram-positive bacteria like Staphylococcus aureus and Bacillus subtilis but not against Gram-negative bacteria like Escherichia coli and Pseudomonas aeruginosa, indicating a typical spectrum of the insect defensin family. In addition, A. dichotoma defensin also exhibited antibacterial activity against methicillin-resistant S. aureus (MRSA) isolated from a patient.
    Biochemical and Biophysical Research Communications 04/1996; 220(3):526-31. · 2.41 Impact Factor
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    ABSTRACT: A genomic clone encoding a new member of attacin, an insect antibacterial protein, was isolated from a genomic library of the silkworm, Bombyx mori, and the nucleotide sequence of the 5'-upstream region was determined. The region contained Bm 1, a highly repetitive element of B. mori and a lipopolysaccharide (LPS) response element (RE)(NF-kappaB binding site), CAAT box and TATA box. Northern blot analysis showed that the attacin gene expression was rapidly induced by bacterial cell wall components such as LPS from Escherichia coli and peptidoglycan (PG) from Micrococcus luteus, suggesting that attacin plays an important role in an early phase of the self-defense system upon bacterial infection.
    Biochemical and Biophysical Research Communications 04/1996; 220(3):594-9. · 2.41 Impact Factor
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    ABSTRACT: To express the cDNA encoding human growth hormone (hGH) in larvae of Bombyx mori, B. mori nuclear polyhedrosis virus (BmNPV) was employed as an expression vector. For the construction of the recombinant virus, the hGH cDNA was inserted into the downstream of the strong polyhedrin promoter to achieve a high level expression. Immunoblot analysis revealed that the virus-mediated hGH was synthesized in the larvae and secreted into the hemolymph. The yield of the recombinant hGH synthesized in the larvae reached to a level of 160 micrograms/ml of hemolymph after purification. The purified recombinant hGH was confirmed to have both the same molecular weight and amino acid sequence at its N-terminal region as those of the natural counterpart. In addition, the biological activity of the recombinant hGH was comparable to that of the natural hGH in the growth-stimulating effect on rat Nb 2 Node lymphoma cells.
    Biochemical and Biophysical Research Communications 09/1995; 213(2):389-96. · 2.41 Impact Factor
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    ABSTRACT: A Bombyx mori cDNA was cloned that hybridized with Hyalophora cecropia attacin probe and its nucleotide sequence was determined. This cDNA consisted of 846 nucleotides and the deduced amino acid sequence showed that the cDNA encodes an attacin precursor protein. The putative mature protein of B. mori attacin had 70.4, 68.3 and 18.8% identity in amino acid sequences with that of H. cecropia acidic and basic attacins and Sarcophaga peregrina sarcotoxin IIA, respectively. B. mori and H. cecropia attacins and S. peregrina sarcotoxin IIA had two subdomains in each G domain, suggesting that common amino acid residues in the subdomains are conserved during evolution and plays an important role in the activity of the antibacterial proteins. Expression of B. mori attacin gene was rapidly induced by the injection of Escherichia coli cells into B. mori larvae and continued at least for 48 h mainly in fat bodies and hemocytes.
    Insect Biochemistry and Molecular Biology 04/1995; 25(3):385-92. · 3.23 Impact Factor
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    ABSTRACT: A cDNA encoding lebocin, a novel member of insect antibacterial peptides, was isolated from the fat body cDNA library of Bombyx mori larvae immunized with Escherichia coli. The cDNA was 844 bp long and had an open reading frame (ORF) containing a probable signal peptide (16 amino acids), a putative prosegment (104 amino acids) and a mature peptide (32 amino acids) followed by 27 additional amino acids at its carboxyl-terminus. Northern blot analysis showed that lebocin gene expression was inducible by bacterial injection, occured tissue-specifically in the fat bodies and continued at least for 48 h post-infection. These results suggest that lebocin has a unique precursor structure and shows typical gene expression pattern as insect antibacterial peptide.
    Biochemical and Biophysical Research Communications. 01/1995;
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    ABSTRACT: The formation of the lipophorin-lipopolysaccharide (LPS) complex in Bombyx mori hemolymph and its role in LPS detoxification were explored. LPS, an antibacterial protein inducer in insects, was injected into B. mori larvae. Analytical density gradient ultracentrifugation revealed that after injection the LPS peak shifts to a zone of lower density with time. The shifted peak was identified as the lipophorin-LPS complex. This complex formation was also achieved in an in vitro mixture of cell-free hemolymph and LPS at 25 degrees C but not at 1 degree C. The lipophorin-LPS complex had a significantly lower capacity to elicit the mRNA of cecropin B, an antibacterial protein. The biological activity of reextracted LPS from the complex was slightly reduced in the Limulus test and no structural modification was observed in sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). These results suggested that the formation of lipophorin-LPS strikingly reduces the cecropin inducibility of LPS without any structural change in LPS. Similar serum lipoprotein-LPS complex formation and reduction of biological activities of LPS were also observed in mammals. We, therefore, suggest that the formation of the serum lipoprotein-LPS complex is a common pathway to inactivate LPS both in insects and in mammals.
    Insect Biochemistry and Molecular Biology 07/1994; 24(6):547-55. · 3.23 Impact Factor