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Biomedical subjects

S Ouchi

Publications and source records attributed to S Ouchi.

At least 19 recordsLinked to original sources
PubMed2000

A hairy root culture of melon produces aroma compounds.

Musk melon is the favorite fruit with a high market value in Japan, and the fragrance is one of the major factors determining the fruit quality of melon. In this study, mutant melon hairy roots which had been induced by means of the T-DNA insertion mutagenesis were found to produce volatile compounds with the fruity fragrance of mature melon. The volatile compounds were extracted and identified by GLC-mass spectrometry. Some essential oils such as (Z)-3-hexenol, (E)-2-hexenal, 1-nonanol, and (Z)-6-nonenol were stably synthesized by these hairy roots despite the increased number of subcultures. The productivity of these compounds by the best hairy root line was shown to be considerably higher than naturally ripened melon fruits.

Cucurbitaceae↗
PubMed1999

Structural analyses of a precursory substance of bitterness: new polyisoprenepolyols isolated from an edible mushroom (Hypsizigusmarmoreus) by fast atom bombardment mass spectrometry.

New polyisoprenepolyols (hypsiziprenol AA and BA) were isolated from an edible mushroom (Hypsizigus marmoreus). These polyols occur as a mixture of homologous polyisoprene derivatives with 40-70 carbon atoms. Analyses by FAB/MS in the positive and negative ion modes are complementary with each other in that the former provides information on the number of hydroxy groups present while the latter specifies the isoprenoid sequence, and thus become a powerful tool for analyzing the structures of polyisoprenepolyols. No polyisoprenepolyols obtained here were found to have antitumor activity on NCI-H292 and EL-4 cell lines.

Agaricales↗
PubMed1998

[Mitral valve replacement for three cases of hypertrophic obstructive cardiomyopathy--surgical treatment].

Three patients with obstructive cardiomyopathy underwent surgical treatment. Mitral valve replacement was performed in all three cases and myectomy of hypertrophic septal muscle was performed in one case. The pressure gradients between the left ventricle and the aorta was less than 10 mmHg in all cases after surgery, Clinical symptoms strikingly improved in three cases. An accurate surgical treatment could be achieved by choosing either myotomy-myectomy, mitral valve replacement or both in the setting of individual condition of each patients.

Cardiomyopathy, Hypertrophic↗
PubMed1997

Characterization and distribution of O-glycosylated carbohydrates in the cell adhesion molecule, contact site A, from Dictyostelium discoideum.

This paper presents further investigation of the properties of carbohydrate II in the cell adhesion molecule, contact site A, from Dictyostelium discoideum. A purified contact site A was digested with Achromobacter protease I to produce a 31-kDa fragment to which carbohydrate II was mainly bound and a 21-kDa fragment containing the NH2 terminus of contact site A, which was identified as Ala-Pro-Thr-Ile-Thr-Ala. The NH2 terminus of the 31-kDa fragment was Thr-Glu-Ala-Thr-Thr-Ser. It was estimated from the cDNA sequence data of contact site A that more than 20 Ser/Thr residues exist as target sites for the O-linked oligosaccharides in the 31-kDa fragment, but not for the N-linked oligosaccharides. These results suggest that carbohydrate II exists as clustered O-linked oligosaccharides in the COOH terminus of contact site A. The results of two-dimensional electrophoresis confirm that oligosaccharides of contact site A contain sialic acids. Immunoelectron microscopy was carried out to define the organelle in which O-glycosylation by carbohydrate II occurs and how carbohydrate II antigens are distributed on the cell surface. The results show that O-glycosylation can occur in the Golgi apparatus in D. discoideum as observed in other cells, although this O-glycosylation was inhibited by tunicamycin. Furthermore, gold particles were densely concentrated in cell-cell contact regions but sparsely distributed in noncontact regions.

Animals↗
PubMed1996

Fast atom bombardment mass spectrometry and linked scan analyses at constant B/E in the structural characterization of new polyisoprenepolyols isolated from an edible mushroom (Hypsizigus marmoreus).

Fast atom bombardment (FAB) mass spectrometry is a powerful tool for analyzing the structure of polyisoprenepolyols. Analyses in the positive and negative ion mode are complementary in that the former provides data on the number of hydroxy groups present while the latter provides data on the isoprenoid sequence. Some of this information is already available from routine FAB mass spectra. More detailed information is contained in the linked scan spectra.

Basidiomycota↗
PubMed1996

Chitinous component of the cell wall of Fusarium oxysporum, its structure deduced from chitosanase digestion.

The cell of Fusarium oxysporum was digested with commercial Bacillus chitosanase. The chitosanase produced low molecular weight heterooligosaccharides consisting of GlcN and GlcNAc from the cell wall. A main component of the digestion products was identified as 2-amino-2-deoxy-beta-D-glucopyranosyl- (1-->4)-2-acetamido-2-deoxy-D-glucopyranose. The chitosanase appeared to be more effective than Streptomyces griseus chitinase for cell wall digestion. Moreover, maltose was unexpectedly found in the digestion products, indicating that the cell wall contains alpha-1,4-linked glucan chain as a polysaccharide component.

Acetylglucosamine↗
PubMed1993

Carbohydrate structures of the cell adhesion molecule, contact site A, from Dictyostelium discoideum.

We determined the carbohydrate structures of contact site A from Dictyostelium discoideum. The carbohydrate moieties of contact site A were released by hydrazinolysis. Fractionation of the deacidified oligosaccharide mixture by Bio-Gel P-4 column chromatography revealed that it was composed of four major oligosaccharides. Their respective structures were determined by sequential exoglycosidase digestion. It is known that contact site A consists of two kinds of carbohydrates, I and II. Taking together the previous and the present results, it was deduced that carbohydrate I comprises N-linked oligosaccharides and carbohydrate II O-linked ones. Furthermore, the relative molar contents of GalNAc and GlcNAc in reducing terminal suggested that contact site A contains 67% of N-linked and 33% of O-linked oligosaccharides.

Animals↗
PubMed1992

Chitinous components of the cell wall of Fusarium oxysporum.

The cell wall of Fusarium oxysporum f. sp. lycopersici was digested with chitinase to analyze the structure of its chitinous components. In spite of a similar acetylation degree of the cell wall components to that of 25-35% acetylated chitosan, only N-acetylglucosamine disaccharide [(GlcNAc)2] was obtained from chitinase hydrolyzate of the fungal cell wall by CM-Sephadex C-25 column chromatography, while (GlcNAc)2 and several types of deacetylated chitooligosaccharides were separated from that of 25-35% acetylated chitosan. The results indicate that N-acetylglucosamine residues in the polysaccharide chains of the fungal cell wall are most likely condensed into some region, while acetylated residues are more scattered in 25-35% acetylated chitosan.

Carbohydrate Sequence↗
PubMed1988

[Respiratory function of mitochondria fractionated from isolated hepatocytes of rats with obstructive jaundice].

Obstructive jaundice model was created using rats by the ligation of bile duct. One, 2, 3 weeks later, the respiratory function and morphology of the hepatic mitochondria were comparatively evaluated between mitochondria directly fractionated from liver tissue and mitochondria from isolated hepatocytes. Respiratory function of the former deteriorated with the duration of jaundice. ATP synthesis decreased to 75% of the control at 1 and 2 weeks, and 58% at 3 weeks after ligation. On the contrary, it was 97%, 88% and 87% of the control. On the contrary, it was 97%, 88% and 87% of the control at 1, 2 and 3 weeks in the latter. By electron microscopic examination, the size of mitochondria of the jaundiced liver is inconsistent and smaller in general than the control. These data suggest that the deterioration of mitochondrial function in the jaundiced liver is not caused mainly by the disturbance of mitochondria themselves, but caused by the respiratory inhibitory factors which exist around the mitochondria.

Animals↗
PubMed1984

Electron spin resonance and electron nuclear double resonance studies of cation radicals derived from tocopherol model compounds.

Electron spin resonance (ESR) and electron nuclear double resonance (ENDOR) measurements were performed for the cation radicals obtained from the model compounds of alpha-, beta-, gamma- and delta-tocopherol (vitamin E) by oxidizing the tocopherol precursors in an AlCl3-CH2Cl2 solution. The proton hyperfine coupling constants and g-values were precisely determined. The ENDOR spectra of the cation radicals of alpha-, beta-, gamma- and delta-tocopherol models in CH2Cl2 at -100 degrees C clearly show 10, 6, 6 and 12 different proton hyperfine couplings, respectively. By varying the temperature, the ESR spectra of the alpha- and delta-tocopherol model cations exhibit line-width alternation phenomena characteristic of the hindered rotation of the OH group. However, neither the beta- nor the gamma-tocopherol model cation radical ESR spectra show any sign of an alternating line-width effect. These results are interpreted by assuming that the beta- and gamma- tocopherol model cations are stabilized in the trans and cis conformations, respectively. On the other hand, both the alpha- and delta-tocopherol model cations exist as cis and trans isomers.

Chemical Phenomena↗
PubMed1982

Antioxidant activities of tocopherols on Fe2+-ascorbate-induced lipid peroxidation in lecithin liposomes.

The antioxidant activities of 4 tocopherols, tocol, and a water-soluble model analog of alpha-tocopherol were compared. Egg lecithin liposomes were used and oxidation was catalyzed by Fe2+-ascorbate. The activities decreased in the order alpha greater than beta greater than gamma greater than delta-tocopherol greater than tocol, in agreement with their potencies in vivo. The water-soluble analog was the least effective. Activity depended on the molar ratio of antioxidant to unsaturated lipid, with one molecule each of the alpha-, beta-, gamma-, delta-tocopherol and tocol capable of protecting, respectively, 220, 120, 100, 30 and 20 molecules of polyunsaturated fatty acid. The mechanism of possible antioxidant effect of the compounds used is discussed.

Ascorbic Acid↗