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Biomedical subjects

S Natori

Publications and source records attributed to S Natori.

At least 73 records · Page 4Linked to original sources
PubMed1998

3 beta-p-hydroxybenzoyldehydrotumulosic acid from Poria cocos, and its anti-inflammatory effect.

The structure of a new triterpene derivative isolated from Poria cocos was determined to be 3 beta-p-hydroxybenzoyldehydrotumulosic acid by spectral and chemical methods. 3 beta-p-hydroxybenzoyldehydrotumulosic acid showed marked inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)- and arachidonic acid (AA)-induced ear inflammation in mice. The 50% inhibitory doses of 3 beta-p-hydroxybenzoyldehydrotumulosic acid were 0.27 and 1.25 mg per ear on TPA- and AA-induced inflammation, respectively.

Animals↗
PubMed1998

Molecular cloning of cDNA for p10, a novel protein that increases in the regenerating legs of Periplaneta americana (American cockroach).

Previously, we purified a protein with a molecular mass of 10 kDa (p10) that increases transiently during the regeneration of legs in the nymphal American cockroach Periplaneta americana, and showed that it is localized exclusively in the cytosol and on the external side of the newly formed epidermis of the regenerating legs [Nomura, A. et al. (1992) Int. J. Dev. Biol. 36, 391-389]. We isolated p10 cDNA and analyzed the expression of the p10 gene. The results indicated that p10 is synthesized as a precursor protein with a putative prosegment including a signal sequence at its N-terminal. The deduced amino acid sequence of p10 showed 53% and 47% identities with those of A10 (a Drosophila antennal protein) and CLP-1 (a moth, Cactoblastis cactorum labial palp protein), respectively. Expression of the p10 gene was shown to be significantly enhanced in regenerating Periplaneta legs. Immunoblotting analysis revealed that p10 was expressed not only in the regenerating legs, but also in the antennae and heads of nymphal and adult cockroaches.

Amino Acid Sequence↗
PubMed1998

Cloning of cDNA for regenectin, a humoral C-type lectin of Periplaneta americana, and expression of the regenectin gene during leg regeneration.

We isolated cDNA for regenectin, a C-type lectin of the American cockroach (Periplaneta americana), and analysed expression of the regenectin gene in the regenerating legs. Regenectin was found to be a member of the Periplaneta lectin-related protein family. We found that the regenectin gene was expressed specifically in the epidermal cells of the newly formed regenerating legs. Together with our previous results, these results suggest that regenectin is synthesized by epidermal cells, secreted into the regenerating leg saccule, and assembles around myoblasts to form leg muscle fibers in situ.

Amino Acid Sequence↗
PubMed1998

Molecular cloning of cDNA and tissue-specific expression of the gene for SII-K1, a novel transcription elongation factor SII.

BACKGROUND: Transcription elongation factor SII has been shown to promote read-through by RNA polymerase II of pausing sites within various eukaryotic genes in vitro by inducing cleavage of the 3'-end of the nascent transcript in the ternary elongation complex. Recently, we showed that various mouse tissues contain multiple SII-related proteins. Of these, 'general SII' was ubiquitously expressed, whereas the others were expressed in a tissue-specific manner. We have identified testis-specific SII (SII-T1) and shown that it was expressed exclusively in spermatocytes. RESULTS: A new SII cDNA clone (pSII-K1) was isolated from mouse kidney. This clone contained an open reading frame which encoded a protein consisting of 347 amino acid residues (SII-K1). A comparison of the amino acid sequences of SII-K1 with those of general SII and SII-T1 revealed that their amino- and carboxy-terminal regions were very similar, but that the sequence of the 95 internal residues (87/181) was unique to each. The recombinant SII-K1 produced in Escherichia coli stimulated RNA polymerase II as did general S-II. The gene for SII-K1 was found to be expressed strongly in the heart, liver, skeletal muscle and kidney, but not in other tissues examined. Contrary to the expression of the general SII gene, the SII-K1 gene was expressed only in 15- and 17-day-old embryos during mouse embryonic development. CONCLUSIONS: We identified a novel member of SII family transcription elongation factor named SII-K1. This factor was expressed exclusively in the heart, liver, kidney and skeletal muscle. During mouse embryonic development, no significant expression of the SII-K1 gene was detected before the formation of these tissues.

Amino Acid Sequence↗
PubMed1998

cDNA cloning of mouse prolyl endopeptidase and its involvement in DNA synthesis by Swiss 3T3 cells.

A cDNA for mouse prolyl endopeptidase (PEP) was cloned and its nucleotide sequence determined. The overall amino acid sequence identity between mouse and other mammalian PEPs was about 96%. A specific inhibitor of PEP, N-benzyloxycarbonyl-thioprolyl-thioprolinal- dimethylacetal (ZTTA), inhibited DNA synthesis by Swiss 3T3 cells. Mouse PEP was shown to be localized partly in restricted nuclear regions. These results suggest that PEP participates in mammalian DNA synthesis.

3T3 Cells↗
PubMed1998

Enhanced expression of an antimicrobial peptide sarcotoxin IA by GUS fusion in transgenic tobacco plants.

To enhance the disease resistance of plants expressing a foreign peptide, the gene for sarcotoxin IA, which is an antimicrobial peptide from an insect consisting of 39 amino acid residues, was introduced into tobacco (Nicotiana tabacum) under the control of a high expression promotor via Agrobacterium-mediated transformation. In transgenic plants, sarcotoxin IA mRNA accumulated to detectable levels, however, the amount of the peptide produced was so small that we could scarcely detect it by protein gel blot analysis, probably because of the instability of short peptides in plant cells. To improve the expression efficiency, genes for four types of amino-terminal and carboxyl-terminal translational fusions of sarcotoxin IA together with the GUS gene were introduced into tobacco. In all four types of transgenic tobacco plants, high level transcripts similar to that in the direct expression sarcotoxin IA construct were found. Protein gel blot analysis with both anti-sarcotoxin IA and GUS antibodies showed production of high levels of fusion protein in all transgenic plants. Among them, three types had abnormal membranes and phenotypes, although no such abnormalities were found in transgenic plants in which only sarcotoxin IA was expressed in a secretable form. All together, these results indicated that, for stable and effective expression of a foreign short peptide in transgenic plants, expression as a fusion protein is useful and that secretion of sarcotoxin IA outside of cells is necessary for generation of useful antimicrobial transgenic plants.

Anti-Bacterial Agents↗
PubMed1998

Inhibitory effects of 5-S-GAD on phosphorylation of V-SRC and BCR-ABL tyrosine kinase.

We examined the inhibitory effects of N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD), a novel antibacterial substance from the immunized adult Sarcophaga peregrina (flesh fly), on protein phosphorylation using immune complexes of protein tyrosine kinases (PTKs) with anti-PTKs monoclonal antibody. We found that 5-S-GAD directly inhibited not only tyrosine phosphorylation of PTK p60(v-src), but also tyrosine phosphorylation of PTK p210(BCR-ABL). The inhibitory potency of 5-S-GAD was comparable to that of radicicol and herbimycin A of PTK inhibitor.

3T3 Cells↗
PubMed1998

Selective inhibition of Src protein tyrosine kinase by analogues of 5-S-glutathionyl-beta-alanyl-L-dopa.

Twelve analogues of the antibacterial phenolic peptide 5-S-glutathionyl-beta-alanyl-L-dopa (5-S-GA-L-D: 1) were synthesized via orthoquinones using tyrosinase. Several synthesized compounds inhibited the v-Src autophosphorylation tyrosine kinase reaction with an IC50 value comparable to that of herbimycin. The inhibition of c-Src substrate phosphorylation was much less active than v-Src autophosphorylation inhibition. The analogues showed no effects on substrate phosphorylation by epidermal growth factor receptor (EGFR), and this selectivity is the most characteristic feature of the analogues (1-12).

Enzyme Inhibitors↗
PubMed1997

Prostaglandin E1 protects against ischemia-reperfusion injury of the liver by inhibition of neutrophil adherence to endothelial cells.

BACKGROUND: This study investigates the protective mechanism of prostaglandin E1 (PGE1) against hepatic ischemia-reperfusion injury in vivo. It has been demonstrated that activated leukocytes contribute to ischemia-reperfusion injury, and that administration of the monoclonal antibody (mAb) for adhesion molecules reduces the injury by inhibiting leukocyte-endothelial cell adhesion. We therefore attempted to find out whether PGE1 has an effect on the inhibition of neutrophil adherence to endothelial cells after reperfusion. METHODS: We administered anti-intercellular adhesion molecule 1 (ICAM-1) mAb, antiserum against rat polymorphonuclear leukocytes, or PGE1 to a rat model of left lobar ischemia for 60 min followed by reperfusion. Leukocyte adherence was observed by intravital fluorescence microscopy. The effect of PGE1 on the expression of adhesion molecules was analyzed by immunohistochemistry and flow cytometry. RESULTS: Ischemia-reperfusion caused endothelial dysfunction and hepatocellular injury with leukostasis in postsinusoidal venules. Anti-ICAM-1 mAb administration or leukopenia ameliorated both the hepatocellular injury and endothelial dysfunction. Although PGE1 administration did not affect the serum interleukin-8 level, it significantly decreased hepatic injury and leukostasis in the reperfused liver. Immunohistochemical findings showed that PGE1 decreased ICAM-1 expression on endothelial cells, but did not affect lymphocyte function-associated antigen 1, and membrane attack complex 1 on neutrophils in flow cytometric analysis. CONCLUSIONS: We conclude that PGE1 protects the liver against ischemia-reperfusion injury by reducing leukocyte-endothelial cell adhesion via down-modulation of ICAM-1 expression on the endothelium.

Alprostadil↗
PubMed1997

Change in the mode of gene expression of the hypopharyngeal gland cells with an age-dependent role change of the worker honeybee Apis mellifera L.

Major proteins synthesized in the hypopharyngeal gland of the worker honeybee change from bee-milk proteins to alpha-glucosidase in accordance with the age-dependent role change of the worker bee. Previously, we showed that the gene for alpha-glucosidase is expressed specifically in the forager-bee gland [Ohashi, K., Sawata, M., Takeuchi, H., Natori, S. & Kubo, T. (1996) Biochem. Biophys. Res. Commun. 221, 380-385]. Here, we describe the isolation and analysis of cDNAs for two bee-milk 56-kDa and 64-kDa proteins. The 56-kDa protein was a glycoprotein which shared 63.2% and 56.9% amino acid sequence identities with proteins encoded by cDNA for royal-jelly-related protein 57-1 (pRJP57-1) and pRJP57-2. The 64-kDa protein cDNA was identical to pRJP57-1. Thus, these bee-milk proteins seem to form a structurally related protein family. The gene for the 64-kDa protein/RJP57-1 was expressed specifically in the nurse-bee gland, whereas that for the 56-kDa protein was expressed in both the nurse-bee and forager-bee glands. mRNAs for the 56-kDa and 64-kDa proteins were detected by in situ hybridization in a whole acinus of the nurse-bee gland, whereas mRNAs for the 56-kDa protein and alpha-glucosidase were detected in that of the forager-bee gland. Therefore, the individual secretory cells of the acinus of the hypopharyngeal gland were shown to express these genes differently with the age-dependent role change of the worker bee.

Aging↗
PubMed1997

Identification of the region in yeast S-II that defines species specificity in its interaction with RNA polymerase II.

Yeast S-II was found to stimulate yeast RNA polymerase II only and not mouse RNA polymerase II. To identify the molecular region of S-II that defines species specificity, we constructed six hybrid S-II molecules consisting of three regions from yeast and/or Ehrlich cell S-II and examined their activity in terms of RNA polymerase II specificity and suppression of 6-azauracil sensitivity in the yeast S-II null mutant. We found that the region 132-270 (amino acid positions) of yeast S-II is indispensable for specific interaction with yeast RNA polymerase II in vitro and for suppression of 6-azauracil sensitivity in vivo. The corresponding region of Ehrlich cell S-II, the region 132-262, was also shown to be essential for its interaction with mouse RNA polymerase II. This region is known to be less conserved than the N- and C-terminal regions in the S-II family suggesting that it is important in the interaction with transcription machinery proteins in a tissue and/or species-specific manner.

Amino Acid Sequence↗
PubMed1997

Chemotherapeutic activity of synthetic antimicrobial peptides: correlation between chemotherapeutic activity and neutrophil-activating activity.

The chemotherapeutic activity of three synthetic antibacterial peptides was investigated. KLKLLLLLKLK-NH2 and its D-enantiomer showed significant chemotherapeutic activity in MRSA-infected mice, whereas KLKLLLKLK-NH2, which showed the highest antibacterial activity among them in vitro, was found to have almost no ability to prevent MRSA infection. These results suggest that the antibacterial activity of peptides assessed in vitro does not necessarily correlate with their chemotherapeutic activity. We found that KLKLLLLLKLK-NH2 and its D-enantiomer, but not KLKLLLKLK-NH2, have the ability to activate human neutrophils to produce superoxide, suggesting that the prevention of MRSA infection by these peptides is not simply due to their direct bactericidal activity but to augmentation of the systemic defense mechanism mediated by neutrophils.

Animals↗
PubMed1997

A novel protease in the pupal yellow body of Sarcophaga peregrina (flesh fly). Its purification and cDNA cloning.

We purified a novel serine protease with a molecular mass of 26 kDa from Sarcophaga pupae. This protease appeared almost exclusively in the yellow body, an organ that develops temporarily in the pupae of dipteran insects and expands to form the adult midgut by engulfing the larval midgut. cDNA analysis revealed that this protease consists of 239 amino acid residues and has significant structural similarity with bovine trypsin (about 40% sequence identity). The 26-kDa protease gene was transiently activated in 1-day-old pupae. The protease was found to cross-react immunologically with antibody against sarcotoxin IA, an antibacterial protein produced by this insect. It is suggested that this protease participates in the decomposition of the larval midgut in the yellow body during metamorphosis.

Amino Acid Sequence↗
PubMed1997

Inhibition of protein tyrosine kinase by 5-S-GAD, a novel antibacterial substance from an insect.

The effect of N-beta-alanyl-5-S-glutathionyl-dopa (5-S-GAD), a compound originally isolated from Sarcophaga peregrina (a flesh fly) as an antibacterial substance, on protein phosphorylation was examined using v-src-transformed NIH3T3 cell lysates. 5-S-GAD was found to inhibit tyrosine phosphorylation of protein tyrosine kinase v-src, but not serine/threonine phosphorylation of protein kinase C. The potency of this compound was comparable to that of herbimycin A. Our results suggested that a substitution at position 5 of the catechol in 5-S-GAD with the sulfur of cysteine is essential for 5-S-GAD to inhibit protein tyrosine kinase v-src.

3T3 Cells↗
PubMed1997

Monoclonal antibodies against pupa-specific surface antigens of Sarcophaga peregrina (flesh fly) hemocytes.

Monoclonal antibodies were raised against pupal hemocytes of Sarcophaga peregrina. Four of the antibodies tested bound specifically to the surface of live pupal hemocytes, and these hemocytes appeared to be granulocytes from their morphology. The antigen recognized by one of the antibodies, MAb 9C8, was considered to be a membrane protein with a molecular mass of 120-kDa. Another antibody, MAb 9F3, was found to recognize possibly the same 120-kDa protein and two cytoplasmic proteins commonly present in both pupal and larval hemocytes.

Animals↗
PubMed1997

Molecular cloning of cDNA for lysenin, a novel protein in the earthworm Eisenia foetida that causes contraction of rat vascular smooth muscle.

Lysenin, which causes contraction of rat vascular smooth muscle, is a protein that was isolated from the earthworm Eisenia foetida. A cDNA encoding lysenin was isolated by use of a partial cDNA probe that had been generated by the PCR with a primer designed by reference to an internal peptide sequence of lysenin. This clone had an ORF encoding 297 amino acid residues. The amino acid sequence deduced from the cDNA revealed the absence of any significant homology to those of previously characterized vasoactive substances. The recombinant lysenin was produced in Escherichia coli. This protein and native lysenin isolated from the earthworm had similar contractive activities when tested on rat aorta. Northern blot analysis of the RNA from various tissues of the earthworm indicated that lysenin is produced by the coelomocytes.

Amino Acid Sequence↗