Biomedical subjects

S Natori

Publications and source records attributed to S Natori.

At least 145 records · Page 8Linked to original sources

PubMed1993

Purification and characterization of the arylphorin gene specific binding protein from an embryonic cell line of Sarcophaga peregrina (flesh fly).

Previously, we purified a DNA binding protein from a nuclear extract of the fat body of Sarcophaga peregrina larvae that binds to the ACCACAACA motif in the 5'-upstream region of the arylphorin gene, and suggested that this protein is a transcriptional activator of the arylphorin gene. In this study, we detected and purified the same protein (ABP-1) from an embryonic cell line of Sarcophaga that does not express the arylphorin gene. Unlike the fat body, which synthesizes arylphorin actively, the embryonic cells were found to contain an additional DNA binding protein (ABP-2) that bound to the same DNA probe as ABP-1, suggesting a novel mechanism of regulation of the arylphorin gene.

Animals↗

PubMed1993

Purification of an AU-rich RNA binding protein from Sarcophaga peregrina (flesh fly) and its identification as a Thiolase.

A protein that binds to the AU-rich sequence in the 3'-untranslated region of sarcotoxin IIA mRNA was purified from a Sarcophaga pupal extract to near homogeneity. The molecular mass of this protein was estimated to be 39 kDa by SDS-polyacrylamide gel electrophoresis. The partial amino acid sequences of two peptides obtained from the 39 kDa protein showed striking similarities to partial amino acid sequences of rat and yeast 3-oxoacyl-CoA thiolase, suggesting that this protein is a Sarcophaga thiolase. In fact, the purified 39 kDa protein was found to have thiolase activity. Moreover, rat mitochondrial 3-oxoacyl-CoA thiolase showed affinity to the AU-rich RNA. These suggest that the RNA binding activity is an intrinsic character of thiolase.

Acetyl-CoA C-Acetyltransferase↗

PubMed1993

Purification of a GTP-binding protein localized in mitochondria.

A particulate fraction consisting of heavy organelles such as nuclei and mitochondria was prepared from Ehrlich ascites tumor cells. From this fraction we have purified a GTP-binding protein with a molecular mass of 33 kDa (MTG33) by guanidine hydrochloride extraction followed by four steps of column chromatography. The Kd value of MTG33 for GTP was 17 nM. [alpha-32P]GTP-binding to MTG33 was inhibited by GTP and GDP, but not appreciably by ATP, CTP, UTP, or GMP. MTG33 hydrolyzed GTP to GDP at a rate of 4.5 mmol/min/mol protein. Subcellular fractionation analysis of mouse liver revealed that the heavy mitochondrial fraction contained the highest level of MTG33. Furthermore, dual immunofluorescence examination indicated that the staining of NIH 3T3 cells with anti-MTG33 antibody is coincident with the distribution of mitochondrial succinate dehydrogenase. Of the mouse organs examined, the heart contained the highest level of MTG33. These results strongly suggest that MTG33 is a GTP-binding protein located in mitochondria.

3T3 Cells↗

PubMed1993

Purification and characterization of a 59-kilodalton protein that specifically binds to NF-kappa B-binding motifs of the defense protein genes of Sarcophaga peregrina (the flesh fly).

Various Sarcophaga peregrina (flesh fly) defense protein genes were shown to be activated when NIH-Sape-4 cells were cultured with bacterial lipopolysaccharides or beta-1,3-glucan. The 5' upstream regions of the defense protein genes were found to have common motifs showing similarity to the mammalian NF-kappa B-binding consensus sequence. A protein with affinity to the NF-kappa B-binding motif of the Sarcophaga lectin promoter was identified and purified to near homogeneity. This 59-kDa protein also bound to the NF-kappa B-binding motifs of other defense protein genes, e.g., sarcotoxin I and sarcotoxin II genes. This protein was found in both the cytoplasmic and the nuclear fractions of the cells, and it appeared to migrate from the cytoplasm to the nucleus on treatment of the cells with lipopolysaccharides. This 59-kDa protein is probably a transcriptional regulator of the genes for defense proteins of S. peregrina.

Animals↗

PubMed1993

Inhibition of SV40 DNA replication in vitro by chlorpromazine.

We examined the inhibitory effect of chlorpromazine, a phenothiazine derivative, on SV40 DNA replication in a HeLa cell extract. The inhibition by chlorpromazine was reversed by cardiolipin, phosphatidylinositol, phosphatidylglycerol, and phosphatidylserine. Studies on a staged reaction showed that the pre-elongation step was sensitive to chlorpromazine: chlorpromazine-resistant DNA synthesis was observed when the drug was added after the pre-elongation step. Analysis of replication products by agarose gel electrophoresis revealed that some steps of DNA chain elongation and maturation of closed circular forms were also sensitive to this drug.

Chlorpromazine↗

PubMed1993

Inhibition of DNA synthesis in Meth A cells by chlorpromazine.

We examined the influence of chlorpromazine, a phenothiazine derivative, on DNA synthesis in Meth A cells. Pulse-labelling experiments with [3H]thymidine showed that chlorpromazine inhibited DNA synthesis in cells cultured in vitro. The drug also inhibited DNA synthesis in isolated nuclei. Observation by fluorescence microscopy of fibroblastic cells stained with chlorpromazine indicated that the drug was localized in the cytoplasm and nuclear membranes, suggesting that it inhibited DNA synthesis in a manner dependent on the interaction of replication proteins with nuclear membranes. Meth A sarcomas growing in the endoderm of BALB/c mice regressed on intra-tumor injection of chlorpromazine, indicating that the drug has an anticancer action.

3T3 Cells↗

PubMed1993

Acromegaly with hyperprolactinemia developed after bilateral adrenalectomy in a patient with Cushing's syndrome due to adrenocortical nodular hyperplasia.

A 27-yr-old woman was referred for evaluation of acromegaly and hyperprolactinemia. She had undergone left adrenalectomy at 12 and right adrenalectomy at 17 for Cushing's syndrome due to adrenocortical nodular hyperplasia. At this time a pituitary tumor was found by brain computerized tomography, but plasma levels of growth hormone (GH), prolactin (PRL) and adrenocorticotropin (ACTH) were normal. When she was 23, symptoms and signs of acromegaly and subsequently galactorrhea-amenorrhea had developed. Plasma GH and PRL were increased and she was followed up by the administration of bromocriptine (2.5 mg-12.5 mg/day, p.o.). However the plasma GH level had been increasing gradually. On admission, plasma GH and PRL were high (19.5 micrograms/L, 61.0 micrograms/L, respectively) and increased in response to thyrotropin releasing hormone (TRH, 500 micrograms i.v.). An intrasella mass, which had been detected when she was 17, had become enlarged and was removed by Hardy's operation. Microscopically, the resected tumor was an eosinophilic adenoma. Immunohistochemical studies showed GH, PRL and ACTH positive cells localized in the tumor. Immunoultrastructural analysis of the tumor confirmed that GH, PRL and ACTH were present in secretory granules and Golgi apparatus in the tumor cells. The patient was a rare case of acromegaly with hyperprolactinemia developed after bilateral adrenalectomy of Cushing's syndrome due to adrenocortical nodular hyperplasia, all of which manifestations may be caused by a GH, PRL and ACTH secreting pituitary adenoma.

Acromegaly↗

PubMed1993

[A case of type II cryoglobulinemia involving glomerulopathy associated with hepatitis C antibody].

We reported a case of type II cryoglobulinemia involving glomerulopathy associated with HCV-induced liver cirrhosis. The patient was a 57-year-old woman. Her past history included chronic hepatitis at 51 years and rheumatoid arthritis at 53 years of age. At 46 years, an erythematous lesion appeared on her legs, which was diagnosed as allergic vasculitis by skin biopsy. At 50 years, proteinuria, hematuria and hypertension were recognized. The next year, the first renal biopsy was performed and showed membranoproliferative glomerulonephritis (MPGN). Recently, the edema of her legs has progressed, and the laboratory data showed proteinuria, hematuria, hypocomplementemia, rheumatoid factor positivity, and increase of monoclonal IgG kappa chain. The second renal biopsy revealed an endocapillary proliferative glomerulonephritis-like lesion with marked infiltration of monocytes and macrophages. The subendothelial deposit showed a fine fibril-like pattern. She was treated with steroids and double filtration plasmapheresis (DFPP) therapy, but the treatment was not very effective. She died of liver cirrhosis, which was probably induced by hepatitis C virus (HCV), and sepsis. Generally, the patients of type II cryoglobulinemia often showed HCV antibody positivity, pointing to HCV as an etiological factor. In this case, renal biopsy was performed twice in the same patient, and the histologic findings suggest the clinicopathological course of cryoglobulinemia.

Chronic Disease↗

PubMed1992

The fate of the prosegment in the acute-phase and programmed synthesis of sapecin, an antibacterial peptide of the flesh fly (Sarcophaga peregrina).

The nucleotide sequence of sapecin cDNA suggested that this antibacterial peptide of the flesh fly (Sarcophaga peregrina) is produced from preprosapecin by post-translational processing. We examined the production of sapecin and its prosegment by radioimmunoassay under two different physiological conditions in which its gene is activated, assuming that the prosegment has some biological role. Results suggested that the prosegment is degraded selectively during production of sapecin. We also found that imaginal discs synthesize sapecin when cultured in the presence of 20-hydroxyecdysone.

Amino Acid Sequence↗

PubMed1992

Reversal by phosphatidylglycerol and cardiolipin of inhibition of transcription and replication by histones in vitro.

We examined the effects of phospholipids on transcription and replication in vitro in the presence of histones. Phosphatidylglycerol and cardiolipin were shown to reverse the inhibitory effects of histones in both random RNA synthesis with purified RNA polymerase II and accurate transcription initiated from the adenovirus 2 major late promoter in a nuclear extract. Phosphatidylserine, phosphatidic acid, and phosphatidylcholine did not activate RNA synthesis although they bound as strongly as phosphatidylglycerol and cardiolipin to histones. Phosphatidylglycerol and cardiolipin also reversed the in vitro inhibition of SV40 DNA replication by histones. Unsaturation of the fatty acid residues was shown to be necessary for the restoration of transcription and replication by phosphatidylglycerol.

Adenoviruses, Human↗

PubMed1992

Purification and characterization of a hemocyte proteinase of Sarcophaga, possibly participating in elimination of foreign substances.

We have reported that foreign protein injected into the abdominal cavity of Sarcophaga peregrina (flesh fly) larvae is degraded in the hemolymph by a proteinase secreted by hemocytes [Suzuki, T. and Natori, S. (1985) Comp. Biochem. Physiol. 81A, 191-193]. Here we report the purification and characterization of a proteinase from larval hemocytes. This enzyme is a cysteine proteinase consisting of 26-kDa and 29-kDa subunits with similar substrate specificity to mammalian cathepsin B. This enzyme was shown to be released from hemocytes into the hemolymph of larvae following injection of sheep red blood cells into the larvae, suggesting that it participates, at least in part, in elimination of foreign substances introduced into the body cavity.

Amanitins↗

PubMed1992

Purification and characterization of a diptericin homologue from Sarcophaga peregrina (flesh fly).

A protein with a molecular mass of 8 kDa was found to be synthesized specifically when the fat-body from injured Sarcophaga peregrina larvae was cultured in vitro. This protein was purified from the haemolymph of the injured larvae to near-homogeneity. Partial amino acid sequencing revealed that this protein is a diptericin homologue. It showed bactericidal activity on growing, but not resting Escherichia coli cells. E. coli cells become elongated on treatment with this protein.

Amino Acid Sequence↗

PubMed1992

Inhibition of Escherichia coli DNA topoisomerase I activity by phospholipids.

The DNA relaxation activity of Escherichia coli DNA topoisomerase I in vitro was greatly inhibited by cardiolipin. Inhibition also occurred to some extent with phosphatidylglycerol from egg yolk. Analysis with synthetic phospholipid revealed that phosphatidylglycerol containing unsaturated fatty acids exhibited a strong inhibitory effect, whereas inhibition by phosphatidylglycerol containing saturated fatty acids was weak. Phosphatidylethanolamine showed no inhibitory effect. Chlorpromazine, which interacts with phospholipids, suppressed the inhibitory effect of cardiolipin. Cardiolipin and phosphatidylglycerol with unsaturated fatty acid precipitated topoisomerase I even at low concentrations, whereas phosphatidylglycerol from egg yolk and a synthetic phosphatidylglycerol containing saturated fatty acids precipitated this enzyme only at high concentrations. One-third of the total topoisomerase I in E. coli was found in the membrane fraction. Treatment of E. coli cells with chlorpromazine resulted in relaxation of plasmid DNA. This DNA relaxation was not observed in a topA mutant, suggesting that this relaxation by chlorpromazine in vivo is catalysed by topoisomerase I.

Chlorpromazine↗

PubMed1992

Purification, gene cloning, and gene disruption of the transcription elongation factor S-II in Saccharomyces cerevisiae.

Saccharomyces cerevisiae S-II was purified to near homogeneity as a protein stimulating RNA polymerase II. Four of seven lysyl endopeptidase-digested fragments of S-II were located in the PPR2 sequence reported previously. Analysis of a genomic clone of S-II revealed that S-II and PPR2 are the same protein consisting of 309 amino acid residues, and frame shifts were found in the sequence of PPR2 gene reported previously. Yeast S-II and mouse S-II showed high similarity in their amino acid sequences, especially in their amino-terminal and carboxyl-terminal regions. A gene disruption experiment showed that an S-II null mutant was not lethal under usual growth conditions, indicating that S-II is not essential for the growth of yeast.

Amino Acid Sequence↗

PubMed1992

Evidence for an increase in positive surface charge and an increase in susceptibility to trypsin of Sarcophaga lectin (from the flesh fly, Sarcophaga peregrina) on its interaction with galactose, a hapten sugar of the lectin.

When Sarcophaga lectin (from the flesh fly, Sarcophaga peregrina), an insect humoral lectin, was eluted from a column of DEAE-cellulose in the presence of galactose (a hapten sugar of this lectin), it emerged at a lower salt concentration than when galactose was absent. In the presence of galactose the lectin was, in addition, more susceptible to trypsin digestion. The lectin was found to have an affinity for basic proteins such as histone H3 and sarcotoxin IA, but this property was lost in the presence of galactose. These results suggested that the lectin changes its conformation on interaction with galactose. This change is suggested to result in the exposure of some hidden lysine and/or arginine residues.

Amino Acid Sequence↗

PubMed1992

Purification of a 29-kDa hemocyte proteinase of Sarcophaga peregrina.

Previously, we suggested the participation of a hemocyte proteinase in the dissociation of fat body of Sarcophaga peregrina (flesh fly) at metamorphosis. We have now purified this proteinase to near homogeneity from pupal hemocytes. It is a cysteine proteinase with a molecular mass of 29 kDa and has a unique substrate specificity hydrolyzing both Suc-Leu-Leu-Val-Tyr-MCA and Z-Phe-Arg-MCA (Suc, succinyl; MCA, methylcoumaryl-7-amide; Z, carbobenzoxy), which are substrates for chymotrypsin and cathepsin B, respectively. Partial similarity was found between the amino-terminal sequence of this proteinase and that of cathepsin B, including Pro, Glu and Arg residues conserved in the papain superfamily of enzymes.

Amino Acid Sequence↗

PubMed1992

Function of the lipopolysaccharide-binding protein of Periplaneta americana as an opsonin.

Previously, we reported the purification of an LPS-binding protein from the hemolymph of the American cockroach that was specific for E. coli LPS. In this study we found that this protein participated in the clearance of E. coli cells injected into the abdominal cavity of the cockroach, and that hemocytes ingested E. coli cells treated with this LPS-binding protein in vitro. These findings suggest that this LPS-binding protein acts as an opsonin.

Acute-Phase Proteins↗

PubMed1992

Induction by psychotropic drugs and local anesthetics of DnaK and GroEL proteins in Escherichia coli.

We examined effects of psychotropic drugs and local anesthetics on the synthesis of heat shock proteins in Escherichia coli. Chlorpromazine, a phenothiazine derivative, was shown to induce DnaK and GroEL proteins, major heat shock proteins in E. coli. The inductions of these proteins were not observed in an rpoH (= htpR) amber mutant strain, indicating that the heat shock sigma factor sigma 32 was required for their inductions. Northern blot hybridization analysis revealed that chlorpromazine induced increases of messenger RNAs for the DnaK and GroEL proteins. Thus, the induction occurred at the level of transcription. Chlorpromazine also induced non-heat shock proteins with molecular masses of 21 kDa, 20 kDa, and 17 kDa, even in the rpoH mutant strain. Other psychotropic drugs and local anesthetics, namely, dibucaine, lidocaine, imipramine, tetracaine and procaine, also induced DnaK and GroEL proteins and the small molecular weight proteins.

Anesthetics, Local↗