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T Hiroi

Publications and source records attributed to T Hiroi.

85 records · Page 5Linked to original sources
PubMed1993

In vitro degradation of mitochondrial proteins by ATP-dependent protease in bovine adrenal cortex.

We have examined in vitro degradation of mitochondrial proteins by ATP-dependent protease in bovine adrenal cortex. Purified ATP-dependent protease degraded at least five proteins in vitro in the presence of ATP and Triton X-100 using mitochondrial fraction as a substrate. Two of the degraded proteins were identified as P-450scc and adrenodoxin reductase by immunoblotting. No degradation of P-45011 beta or adrenodoxin was detected. Purified P-450scc and adrenodoxin reductase were also degraded. By analyzing degradation products of P-450scc we identified 49 peptides and 59 cleavage sites. The size of the products was between 3 and 18 amino acid residues. The protease preferentially cleaved the carboxy-side of Leu, Phe, Ala, Val, Met, and some other amino acids. Since the protease (a matrix enzyme) is accessible to P-450scc and adrenodoxin reductase localized on the matrix side of inner membrane, the present results suggest that the protease might participate in the turnover of these two proteins and some other mitochondrial proteins.

ATP-Dependent Proteases↗
PubMed1992

De novo glucan synthesis by mutants streptococcal glucosyltransferases present in pellicle promotes firm binding of Streptococcus gordonii to tooth surfaces.

Adherence of 3H-labelled cells of Streptococcus gordonii and Streptococcus milleri to artificial pellicles prepared from saliva supplemented with glucosyltransferases from mutants streptococci was examined using a new assay for sucrose-dependent cell-to-pellicle attachment. Results indicate that S. gordonii, but not S. milleri, could attach tightly to hydroxylapatite surfaces through de novo glucan synthesis by mutants streptococcal glucosyltransferases present in the experimental salivary pellicles.

Bacterial Adhesion↗
PubMed1992

Sulfur amino acid levels and related enzyme activities in various brain regions (and other tissues) in normal mice and rolling mice Nagoya.

The contents of the sulfur amino acids, and the activities of cystathionine beta-synthase and cystathionine gamma-lyase were measured in various regions of the brain and several other tissues in both normal mice and rolling mice Nagoya. The cystathionine content and cystathionine beta-synthase activity were found to be unevenly distributed in various regions of the brain in both normal mice and rolling mice Nagoya, being highest in the cerebellum. Except for the mesencephalon and thalamus plus hypothalamus, the cystathionine content and cystathionine beta-synthase activity in the brain regions of rolling mice Nagoya were much higher than those of the normal mice. The cystathionine content after D,L-propargylglycine treatment was also found to be unevenly distributed in various brain regions in both normal mice and rolling mice Nagoya. The concentrations of cystine and methionine were also higher in all regions of the brain of rolling mice Nagoya than those of normal mice, while the concentration of taurine in the various regions of the brain was almost the same in normal mice and rolling mice Nagoya. Cystathionine beta-synthase and cystathionine gamma-lyase activities in the liver, kidney, and pancreas were almost the same in both the normal mice and rolling mice Nagoya.

Amino Acids, Sulfur↗
PubMed1992

[Central type of sleep apnea syndrome caused by unilateral lateral medullary infarction].

We reported here a 64-year-old man with a central apnea resulted from unilateral medullary infarction. He was admitted because of cerebellar ataxia, dysarthria and dysphasia of abrupt onset. After the injection of diazepam for alcohol forbidden syndrome, he induced complete apnea and required the endotracheal intubation. At the spontaneous respiration under room air, his arterial blood gas showed hypercapnea without hypoxemia, and he fell into severe hypoventilation when hypnotic drug was injected. Respisomnogram revealed the frequent presence of central apnea both while he was awake and asleep. MRI demonstrated an abnormal high intensity area on T2 weighted image at the right lateral medulla just below the ponto-medullary junction. At autopsy, areas of the infarction were limited within the right lateral medulla, including lateral portion of the medullary reticular formation, the ambigual nucleus, one part of the solitary nuclear complex, the inferior cerebellar peduncle and the spinal trigeminal nucleus. However, the dorsomotor nucleus of vagus was completely free from the infarct lesion. There was no other lesion within central nervous system. Such a distribution seemed the minimal extent of the lesion responsible for central, apnea compared to the previous reports. We suggest that central apnea occurs not infrequently in the cases of Wallenberg's syndrome.

Cerebellar Ataxia↗
PubMed1990

Linkage of phenolic acids to cell-wall polysaccharides of bamboo shoot.

Hydrolysis of bamboo shoot cell walls with Driselase (a fungal enzyme preparation) gave xyloglucan and arabinoxylan oligosaccharides containing ferulic and p-coumaric acids, respectively. The structures of two oligosaccharides containing phenolic acids are here determined to be O-(4-O-trans-feruloyl-alpha-D-xylopyranosyl)-(1----6)-D-glucopy rano se and O-[5-O-(trans-p-coumaroyl(-alpha-L-arabinofuranosyl]-(1----3)-O-be ta-D-xylopyranosyl-(1----4)-D-xylopyranose, on the basis of n.m.r. spectroscopy, methylation analysis, and f.a.b.-m.s. The possible role of phenolic acid substituents in cell-wall architecture is discussed.

Carbohydrate Conformation↗
PubMed1990

Feruloylated xyloglucan and p-coumaroyl arabinoxylan oligosaccharides from bamboo shoot cell-walls.

A novel feruloylated xyloglucan disaccharide and p-coumaroylated arabinoxylan trisaccharide were isolated from cell walls of growing bamboo (Phyllostachys edulis) shoots. On the basis of chemical and spectral data, their structures were determined to be O-(4-O-trans-feruloyl-alpha-D- xylopyranosyl)-(1----6)-D-glucopyranose and O-[5-O-(trans-p-coumaroyl)- alpha-L-arabinofuranosyl]-(1----3)-O-beta-D-xylopyranosyl-(1----4)-D- xylopyranose, respectively. This is the first reported evidence of a phenolic acid covalently associated with the cell wall hemicellulose, xyloglucan.

Carbohydrate Conformation↗
PubMed1990

[Initial-plaque forming ability of glucosyltransferases from Streptococcus mutans serotype C strain].

In order to clarify functional roles of extracellular glucosyltransferases (GTases) from S. mutans serotype c in initial stage of plaque formation, GTase-I and GTase-S were purified from culture fluids of strain PS 14. And an ability of these GTases to enhance cellular attachment of oral streptococci was investigated using 3H labeled resting cells of S. sanguis Challis and S. milleri Is 57. The results were as follows: 1) From culture fluids of strain PS 14 grown in a M 4 medium supplemented with 1% ammonium sulfate, GTase-I was purified by ammonium sulfate fractionation, CM-cellurose column chromatography and Toyopearl HW-55 gelfiltration. Also, GTase-S was purified by the method of Baba et al from the culture fluids of strain PS 14 grown in a dialyzed BHI medium. Purified GTase-I and GTase-S were almost homogeneous, and had a molecular size of 160 KDa and 145 KDa respectively (by SDS-PAGE). 2) Sucrose-dependent attachment of S. sanguis cells to experimental pellicles was markedly enhanced by the addition of crude GTase in saliva. This fact was conformed by a scanning electron microscopic observation of the attachment cells. Such enhanced attachment necessitated a long-term incubation (greater than 10 h) of the cells in the presence of sucrose, suggesting that it is correlated to de novo glucan synthesis. 3) Purified GTase-I also had an ability to enhance the cellular attachment of S. sanguis cells as well as crude GTase, while purified GTase-S didn't have. Neither crude enzyme, GTase-I nor GTase-S have an ability to enhance significantly the cellular attachment of S. milleri cells. However, S. milleri pretreated with the preparations containing GTase-S gained the ability to attach to experimental pellicles prepared from saliva supplemented with GTase-I. These results suggest that the cellular attachment system mediated by enzymatic action (s) of GTase (s) from serotype c S. mutans be present and function in the first stage of plaque formation.

Cell Adhesion↗