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S Shinoda

Publications and source records attributed to S Shinoda.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cloning of a full-length cDNA encoding ent-kaurene synthase from Gibberella fujikuroi: functional analysis of a bifunctional diterpene cyclase.

We report here the nucleotide sequence of a full-length cDNA encoding ent-kaurene synthase that was isolated by a reverse-transcription polymerase chain reaction from Gibberella fujikuroi (Gcps/ks). This cDNA encodes 952 amino acid residues with a relative molecular mass of 107 kDa. The sequence similarity between Gcps/ks and ent-kaurene synthase of the gibberellin A1-producing fungus, Phaeosphaeria sp. L487, is very high, suggesting that Gcps/ks is also a bifunctional diterpene cyclase. Its recombinant protein expressed in Escherichia coli converted geranylgeranyl diphosphate to copalyl diphosphate and ent-kaurene.

Alkyl and Aryl Transferases↗
PubMed2000

Lanthanide complexes as smart CD probes for chirality sensing of biological substrates.

Lanthanide tris(beta-diketonates) and porphyrinates acted as effective circular dichroism (CD) probes for chirality sensing of neutral and zwitterionic guests. They were electrically neutralized but formed highly coordinated 1:1 complexes with various guests. When a chiral, non-chromophoric guest was combined with a chromophoric lanthanide probe, the resulting highly coordinated complex exhibited characteristic CD signal, the sign of which was dependent on the absolute configuration of the bound guest. Since there are wide variations of coordinating ligands and lanthanide centers, lanthanide coordination chemistry offers great possibilities for the design of new CD chirality sensory systems especially for biologically important guests.

Amino Acids↗
PubMed1999

Cysteine biosynthesis in Saccharomyces cerevisiae: a new outlook on pathway and regulation.

Using a Saccharomyces cerevisiae strain having the activities of serine O-acetyl-transferase (SATase), O-acetylserine/O-acetylhomoserine sulphydrylase (OAS/OAH SHLase), cystathionine beta-synthase (beta-CTSase) and cystathionine gamma-lyase (gamma-CTLase), we individually disrupted CYS3(coding for gamma-CTLase) and CYS4 (coding for beta-CTSase). The obtained gene disruptants were cysteine-dependent and incorporated the radioactivity of (35)S-sulphate into homocysteine but not into cysteine or glutathione. We concluded, therefore, that SATase and OAS/OAH SHLase do not constitute a cysteine biosynthetic pathway and that cysteine is synthesized exclusively through the pathway constituted with beta-CTSase and gamma-CTLase; note that OAS/OAH SHLase supplies homocysteine to this pathway by acting as OAH SHLase. From further investigation upon the cys3-disruptant, we obtained results consistent with our earlier suggestion that cysteine and OAS play central roles in the regulation of sulphate assimilation. In addition, we found that sulphate transport activity was not induced at all in the cys4-disruptant, suggesting that CYS4 plays a role in the regulation of sulphate assimilation.

Biological Transport↗
PubMed1999

The ability of Vibrio vulnificus to use a synthetic hydrophilic heme compound, Fe-TPPS, as a single iron source.

Vibrio vulnificus, an opportunistic human pathogen, can obtain iron from a variety of heme proteins. This process involves the digestion of heme proteins by an exoprotease to liberate protoheme (iron-protoporphyrin IX). In the present study, we tested whether this pathogen also uses a synthetic heme compound, Fe-alpha,beta,gamma,delta-tetraphenylporphine tetrasulfonic acid (Fe-TPPS), as an iron source. When inoculated into a medium containing Fe-TPPS, V. vulnificus L-180 multiplication was seen to be dependent on the concentration of the synthetic heme compound; a mutant lacking the ability to utilize protoheme did not multiply. Cells of the strain grown under the iron-restricted condition showed time-dependent uptake of Fe-TPPS. The ability to use either protoheme or Fe-TPPS was significantly reduced by the addition of an excess amount of free TPPS or Cu-TPPS. The data suggest that, V. vulnificus may assimilate Fe-TPPS, at least partially, through the same system as that for protoheme.

Blood↗
PubMed1999

Role of the sulphate assimilation pathway in utilization of glutathione as a sulphur source by Saccharomyces cerevisiae.

Mutants unable to grow on medium containing glutathione as a sole source of sulphur (GSH medium) were isolated from Saccharomyces cerevisiae strains carrying met17(deficiency of O-acetylserine and O-acetylhomoserine sulphydrylase). They were defective in the high-affinity glutathione transport system, GSH-P1. Newly acquired mutations belonged to the same complementation group, gsh11. However, it became apparent that gsh11 conferred the mutant phenotype not by itself but in collaboration with met17. Moreover, mutations conferring the defect in sulphate assimilation made the cell unable to grow on GSH medium in collaboration with gsh11. From this finding, we propose that the sulphate assimilation pathway acts as a sulphur-recycling system and that this function is especially vital to the cell when the supply of glutathione is limited.

Glutathione↗
PubMed1999

Siderophore production of Vibrio parahaemolyticus strains from different sources.

Vibrio parahaemolyticus strains isolated from different sources were assayed for their ability to produce a siderophore, vibrioferrin, under iron-limited growth conditions. The mean value +/- standard error of mean (microM vibrioferrin in spent culture supernatant/optical density at 660 nm) was 832.3 +/- 66.9 for clinical isolates (n=44), which was significantly higher (P<0.01) than those for food isolates (461.0 +/- 66.5; n=37) and coastal isolates (378.8 +/- 37.2; n=26). This suggests that greater productivity of vibrioferrin by clinical isolates may be associated with a selective advantage for survival and proliferation under conditions of iron-limitation such as in the intestine [corrected].

Citrates↗
PubMed1999

The hemagglutinating action of Vibrio vulnificus metalloprotease.

Vibrio vulnificus protease (VVP), a 45-kDa zinc metalloprotease, consists of two functional domains: an N-terminal 35-kDa polypeptide having endoproteinase activity, and a C-terminal 10-kDa polypeptide that mediates the binding of VVP to the erythrocyte membrane. Therefore, VVP, but not its N-terminal endoproteinase domain alone, has agglutinating activity to rabbit erythrocytes. When a single zinc atom in the catalytic center was substituted by treatment with CuCl2 or NiCl2, proteolytic and hemagglutinating activities were reduced by Ni substitution but not by Cu substitution. Cu-treated 35-kDa polypeptide showed sufficient affinity of the catalytic center and weak binding ability to the erythrocyte membrane, but the Ni-treated polypeptide did not. These results suggest that the binding of endoproteinase domain to membrane is also necessary for hemagglutination.

Animals↗
PubMed1999

[Percutaneous dilational tracheostomy: report of 9 cases].

Nine patients with CNS damage who had been transferred to our critical care unit were treated with a commercially available kit for percutaneous dilational tracheostomy (PDT). The mean procedure time was about 11 minutes, and the perioperative complication rate was 22% (2/9). Only one complication, wound infection, occurred, and the patient was cured with conventional therapy. On the other hand, premature extubation of the translaryngeal tube occurred in one case. Long-term complications like tracheal stenosis and tracheal malacia were not experienced in two patients. They were discharged from the hospital after decannulation. In conclusion, the advantages of PDT include a short procedure time, the ability to perform the procedure at the bedside, and reduced stimulation of the trachea. Because of the safety and simplicity of the procedure, we recommend PDT for patients with CNS damage.

Adult↗
PubMed1999

Protein toxins produced by pathogenic vibrios.

Genus Vibrio includes some pathogenic species which are classified into two groups: a gastrointestinal infection group and an extraintestinal infection group. The vibrios produce various toxic proteins. Cholera toxin (CT) produced by V. cholerae O1 and O139 is a factor causing diarrhea with severe dehydration by ADP-ribosylation of the alpha subunit of the GTP-binding protein which stimulates adenylate cyclase activity. CT-like toxins are found in some strains of V. cholerae non-O1 or V. mimicus, but not in V. parahaemolyticus, another major diarrheagenic vibrio species. A thermostable direct hemolysin (TDH) is thought to be the pathogenic factor causing diarrhea in the vibrio. Hemolysin is the most widely distributed toxin in the pathogenic vibrios and plays various roles in the infection process. Protease activity is also common in the vibrios. Many of the proteases produced by the vibrios are a metalloprotease having a zinc atom immunologically cross reactive to each other. The proteases act not only for processing and activation of protein toxins but also direct toxic factors causing edematous or hemorrhagic skin lesions or disturbance of host defense system.

Diarrhea↗
PubMed1998

Histamine enhances UVB-induced IL-6 production by human keratinocytes.

Histamine, an important mediator in immediate-type hypersensitivity, is elevated in the skin of patients with atopic dermatitis and is considered to play a pathogenic role in atopic dermatitis. In this study, to elucidate the mechanism of sun exposure-induced exacerbation of skin lesions in atopic dermatitis, we examined the effect of histamine on proinflammatory cytokine production of keratinocytes induced by ultraviolet (UV) B irradiation. Cultured human keratinocytes were irradiated with 30 mJ/cm2 of UVB and incubated with histamine over the concentration range 10(-7) to 10(-4) M, and the IL-1alpha and IL-6 released into the medium were measured using an ELISA. Histamine weakly stimulated IL-6 production by itself. However, together with UVB, it synergistically enhanced IL-6 production and the amount of IL-6 mRNA as estimated by reverse-transcription polymerase chain reaction (RT-PCR). Histamine had a dose-dependent effect which was maximal at a concentration of 10(-5) M, and had no effect on the kinetics of IL-6 production. In contrast, histamine had no effect on IL-1alpha production by keratinocytes. The effect of histamine was completely blocked by pyrilamine, an H1 receptor antagonist, and mimicked by the H1 receptor agonist, 2-methylhistamine. Whereas the H2 receptor antagonist, cimetidine, slightly inhibited the effect of histamine and the effect of the H2 receptor agonist, 4-methylhistamine, was minute. These results show that histamine augments UVB-induced IL-6 production by keratinocytes predominantly via the H1 receptor at the level of transcription. This suggests a contributory role for histamine in the exacerbation of atopic dermatitis induced by sun exposure.

Adult↗
PubMed1998

Reduced interferon gamma production by antigen-stimulated cord blood mononuclear cells is a risk factor of allergic disorders--6-year follow-up study.

BACKGROUND: It is not sufficient to predict 'high allergic risk newborns' on the basis of increased IgE concentrations of cord blood alone, because a raised cord blood IgE concentration is specific but not sensitive in the prediction of the development of allergic disorders. Warner et al. have reported that interferon gamma (IFN-gamma) production by allergen-triggered cord blood cells is a predictor of atopic eczema, based on the 1-year follow-up study. OBJECTIVE: We examined whether IFN-gamma production by antigen-stimulated cord blood mononuclear cells (CBMCs) is a risk factor of allergic disorders, based on the 6-year follow-up study. METHODS: The relationships among cord blood IgE concentrations, IFN-gamma and interleukin-2 (IL-2) productions by antigen-stimulated CBMCs, and the development of allergic disorders in 21 infants for 6 years were investigated. RESULTS: Atopic dermatitis, atopic dermatitis and allergic rhinitis, or atopic dermatitis and bronchial asthma developed in seven of 21 subjects. The maximal IFN-gamma concentration in culture supernatants of ovalbumin (OA) or bovine serum albumin (BSA) stimulated CBMCs in infants who developed allergic disorders was significantly lower (P < 0.01) than that in infants who did not develop any allergic disorders. In contrast, the maximal IL-2 concentration in culture supernatants of OA- or BSA-stimulated CBMCs in infants who developed allergic disorders was not lower than in infants who did not develop any allergic disorders. Moreover, the IFN-gamma concentrations were negatively correlated with cord blood IgE concentrations. CONCLUSION: Reduced IFN-gamma production by antigen-stimulated CBMCs is a risk factor of allergic disorders.

Antigens↗
PubMed1998

Bilateral spontaneous dissection of the posteroinferior cerebellar arteries: case report.

OBJECTIVE AND IMPORTANCE: Cervicocerebral arterial dissections occur when blood extrudes into the wall of an artery supplying the brain. The resulting intramural hematoma may compromise the lumen and cause an aneurysmal dilation. Dissecting aneurysms are now recognized with increasing frequency as a cause of strokes. They usually occur spontaneously or are associated with trivial trauma to the artery. A dissecting aneurysm of the posteroinferior cerebellar artery (PICA) is very rare, however. We present a case with ischemic episode and successive subarachnoid hemorrhage caused by bilateral dissection of the PICAs. CLINICAL PRESENTATION: A 47-year-old man experienced sudden onset of cerebellar infarction that rapidly resulted in subarachnoid hemorrhage. Angiography revealed a typical pearl-and-string sign in the right PICA and an irregular stenosis in the left PICA. The patient died shortly after admission. Autopsy demonstrated bilateral dissection of the PICAs not involving the vertebral artery. CONCLUSION: The incidence of intracranial dissecting aneurysms most frequently occurs in the vertebral artery, but the PICA is only rarely involved, especially bilaterally. We are not aware of any other such case in the literature.

Aortic Dissection↗
PubMed1998

Detection of genes encoding cholera toxin (CT), zonula occludens toxin (ZOT), accessory cholera enterotoxin (ACE) and heat-stable enterotoxin (ST) in Vibrio mimicus clinical strains.

A total of 51 clinical strains of Vibrio mimicus were searched for the presence of virulence-associated genes, like ctx, zot or ace genes which locate in "cholera virulence cassette," and the st gene by polymerase chain reaction. Moreover, the pathological potential of each clinical strain was also examined by rabbit ileal loop (RIL). Three strains showed to have the ctx gene, of which only one strain was zot gene-positive. Meanwhile, one other strain was zot+ but ctx-. All of these four strains were found to have the ace gene and to belong to serogroup O115. Nine strains showed to carry the st gene. However, none of these ST-gene-positive strains was indicated to contain the genes located in the "cholera virulence cassette." It is of interest to note that all of the RIL-positive and/or virulence gene-positive strains were restricted to three serogroups, O20, O41 and O115. These results suggest a significant association between O antigens and enterotoxic activities in V. mimicus clinical strains, and clearly demonstrate multifactorial virulence potentials of this human pathogen.

Animals↗
PubMed1998

Characterization of the hemorrhagic reaction caused by Vibrio vulnificus metalloprotease, a member of the thermolysin family.

Vibrio vulnificus is an opportunistic human pathogen causing wound infections and septicemia, characterized by hemorrhagic and edematous damage to the skin. This human pathogen secretes a metalloprotease (V. vulnificus protease [VVP]) as an important virulence determinant. When several bacterial metalloproteases including VVP were injected intradermally into dorsal skin, VVP showed the greatest hemorrhagic activity. The level of the in vivo hemorrhagic activity of the bacterial metalloproteases was significantly correlated with that of the in vitro proteolytic activity for the reconstituted basement membrane gel. Of two major basement membrane components (laminin and type IV collagen), only type IV collagen was easily digested by VVP. Additionally, the immunoglobulin G antibody against type IV collagen, but not against laminin, showed sufficient protection against the hemorrhagic reaction caused by VVP. Capillary vessels are known to be stabilized by binding of the basal surface of vascular endothelial cells to the basement membrane. Therefore, specific degradation of type IV collagen may cause destruction of the basement membrane, breakdown of capillary vessels, and leakage of blood components including erythrocytes.

Animals↗
PubMed1998

Glutathione transport systems of the budding yeast Saccharomyces cerevisiae.

The budding yeast Saccharomyces cerevisiae was shown to have two kinetically distinguishable glutathione transport systems. While one with high affinity (GSH-P1; KT = 0.045 mM) was regulated, the other with low affinity (GSH-P2; KT > 2 mM) was not. GSH-P1 was highly specific to glutathione, and its activity was quickly lost by suspending the cells in buffer solutions. This activity loss was not observed if glucose-containing buffer was used. In addition, rho-isolates had only about one half of the glutathione transport activity of the original (rho+) strain. Therefore, it is concluded that GSH-P1 is an ATP-driven transport system. Strong and moderate inhibition of GSH-P1 by protonophores and ionophores, respectively, are attributed to competition for ATP between GSH-P1 and proton- and cation-pumps, respectively.

Adenosine Triphosphate↗
PubMed1998

[A huge retrocerebellar arachnoid cyst with syringomyelia: case report].

The authors report a case of a huge posterior fossa arachnoid cyst with syringomyelia. This 22-year-old man presented with a history of drop attacks. Magnetic resonance imaging demonstrated ventricular hydrocephalus, a huge posterior fossa arachnoid cyst and syringomyelia. Cyst-peritoneal shunting was installed. The patient had an uneventful postoperative course, and his drop attacks disappeared. Magnetic resonance imaging one month after surgery showed reduction of the ventricular size and size of the arachnoid cyst and syrinx. Large arachnoid cysts in the posterior fossa are reported occasionally, but rare with syrinx. The authors described this case to illustrate the possible contribution of the pathogenesis of the syringomyelia associated with a huge posterior fossa arachnoid cyst.

Adult↗