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Y Inoue

Publications and source records attributed to Y Inoue.

At least 1,027 records · Page 57Linked to original sources

Mechanism of mutagenesis induced by cytosine analogs bearing N(4)-substitutions.

The mechanism of mutagenesis induced by dihydropyrimido [4,5-c][1,2]oxazin-7-one deoxyriboside, P-nucleoside, was studied. This analog is highly mutagenic toward Escherichia coli and Salmonella typhimurium. In E. coli, it induces GC-to-AT and AT-to-GC transitions specifically. No transversions are inducible. P-nucleoside was highly mutagenic to a wild-type E. coli, but little mutagenic in a strain lacking thymidine kinase. This indicates that P-nucleoside may be phosphorylated by thymidine kinase after its uptake into bacteria. The mutagenesis induced by P-nucleoside was efficiently inhibited by the addition of thymidine. This inhibition further confirmed the involvement of thymidine kinase in the first step of the metabolism of P-nucleoside in the bacterial cells. These findings indicate that P-nucleoside is a mutagen of a nucleoside-analog type, causing mutations by the erroneous incorporation and replication. The experiments to prove its ambiguous nature in DNA synthesis is now under way.

Adenine↗

[Experience with the Groshong port in a home TPN patient--a case report].

We experienced a home TPN patient using Groshong port. A 45-year-old woman, recurrent pancreatic head cancer, was treated with home TPN. The Groshong port was inserted via external jugular vein and stayed at home for 8 months with home TPN. Lipid emulsion was administered twice a week. After administration of lipid emulsion, 20 ml of saline was injected and catheter lock was performed with only saline. Heparin was not used for catheter lock. After 8 months' home TPN, patient died. We could not find any precipitate in the catheter and reservoir. A unique feature of Groshong port is a pressure-sensitive two-way valve at the intravascular end. The valve of this port opens outward during fluid infusion or bolus injection. During blood withdrawal, the valve opens inward and then closed after the procedure. Because the valve is designed to remain closed between -7 and 80 mmHg, it will not open spontaneously under normal central venous pressure conditions. This valve eliminates the need for heparin flusing. Catheter obstruction during prolonged TPN is a serious complication. Compound of heparin, lipid emulsion and electrolytes, especially calcium is now becoming one of the most important causes of catheter obstruction and catheter removal. We used the Groshong port to prevent catheter obstruction. After 8 months' use of this port, no precipitate was found in this port. We conclude that the Groshong port is useful for home TPN catheter because it can prevent catheter obstruction due to heparin-lipid-electrolytes compound.

Female↗

[Home parenteral nutrition for terminal cancer patients--when should we tell the truth about their disease and return them to their home with HPN].

Home parenteral nutrition (HPN) is a significant way to enable terminally ill cancer patients to live with high quality of life at home. However, the most important condition to perform HPN is the patients' desire to return to their home. For this purpose, we should consider in informing them of the truth of their disease. We had three terminal cancer patients who returned to their home with HPN. Cas 1: 52-year-old woman, recurrent stomach cancer. She did not know her cancer. She stayed at home for 45 days with HPN. Case 2: 46-year-old woman, recurrent stomach cancer. She did not know her recurrence of cancer. She stayed at home for only 15 days with HPN. Case 3: 45-year-old woman, recurrent pancreatic head cancer. She knew her disease and her life expectancy. She had 6-year-old daughter and desired to return home. She stayed at home with HPN for 8 months. As we told Case 3 truth of her disease when she was diagnosed as recurrence of cancer, she lived at home with HPN for 8 months. From the experience of three cases, we may concluded that, the sooner the patients are informed the truth about their disease, the longer they can stay at home with HPN and spend their limited time with high QOL.

Female↗

Fourier transform infrared spectrum of the radical cation of beta-carotene photoinduced in photosystem II.

A Fourier-transform infrared (FTIR) spectrum of the radical cation of beta-carotene photoinduced in photosystem II (PSII) membranes was obtained at 80K under oxidizing conditions, by utilizing the light-induced FTIR difference technique. Formation of the beta-carotene cation was monitored with the electronic absorption band at 993 nm. An FTIR spectrum of a chemically-generated beta-carotene cation in chloroform was also measured and compared with the spectrum of PSII. Since the FTIR bands of carotenoid cation have characteristic features with strong intensities, they can be useful markers in studying the reaction of carotenoid in PSII.

Carotenoids↗

Differential reactivity of two types of N-glycolyneuraminic acid dimers toward enzymatic and nonenzymatic hydrolysis of their interketosidic linkages.

The kinetics of acid- and sialidase-catalyzed hydrolysis of the interketosidic linkages of two different disialic acids, Neu5Gc alpha 2-->5-OglycolylNeu5Gc and Neu5Gc alpha 2-->8Neu5Gc, were studied. The former sequence was recently identified in the polysialic acid chains of a sialic acid-rich glycoprotein isolated from the egg jelly coat of two different species of sea urchins, and the latter was previously found in the cortical alveolar-derived polysialoglycoprotein from rainbow trout eggs. At pH values < 3.8, the rate of hydrolysis of Neu5Gc alpha 2-->5-OglycolylNeu5Gc was greater than that of Neu5Gc alpha 2-->8Neu5Gc. Paradoxically, however, Neu5Gc alpha 2-->5-OglycolylNeu5Gc was more stable than Neu5Gc alpha 2-->8Neu5Gc at pH values > 3.8. These findings indicate a greater contribution of intramolecular general acid catalysis to the lability of the alpha 2-->5-ketosidic linkage. Neu5Gc alpha 2-->5-OglycolylNeu5Gc was a poor substrate for Arthrobacter ureafaciens, Clostridium perfringens, and Vibrio cholerae sialidases, in contrast to Neu5Gc alpha 2-->8Neu5Gc. Neu5Gc alpha 2-->5-OglycolylNeu5Gc was essentially resistant to hydrolysis by A. ureafaciens sialidase.

Carbohydrate Sequence↗

Chemical crosslinking studies of extrinsic proteins in cyanobacterial photosystem II.

Chemical crosslinking with a zero-length crosslinker, 1-ethyl-3-(3-dimethylaminopropyl) carbodimide hydrochloride, was applied to a cyanobacterial photosystem II complex retaining three extrinsic proteins, the 33 kDa manganese-stabilizing protein, cytochrome (cyt) c-550 and the 12 kDa protein. Three major crosslinked products were obtained in addition to the crosslinked product between the extrinsic 33 kDa and the intrinsic CP47 proteins. They were identified to be: cyt c-550-12 kDa; cyt c-550-12 kDa-33 kDa; D2-cyt c-550-12 kDa. These results indicate that the three extrinsic proteins are closely located with each other in cyanobacterial PSII, supporting the previous proposal that, like the 33 kDa protein; cyt c-550 and the 12 kDa protein are associated with PSII at the lumenal side of thylakoids. The results also suggested that the D2 reaction center protein provides a direct binding site for the extrinsic cyt c-550.

Binding Sites↗

Role of disulfide linkage and putative intermolecular binding residues in the stability and binding of the extrinsic manganese-stabilizing protein to the photosystem II reaction center.

Site-directed mutations were produced at three highly conserved amino acid positions of MSP of the photosystem II (PSII) reaction center in the transformable cyanobacterium Synechocystis sp. PCC6803. The highly conserved aspartate at position 9 of the mature MSP was changed to a lysine (strain MSP-D9K) to assess its role in the proposed N-terminal binding region (Eaton-Rye & Murata, 1989; Odom & Bricker, 1992). This strain accumulates normal levels of MSP, and the properties of the H2O-splitting enzyme are only slightly altered relative to the wild-type. In contrast, replacement of cysteine 20 with a serine, which is proposed to disrupt the intramolecular disulfide bridge (Tanaka et al., 1989), produces a phenotype with no detectable accumulation of MSP, despite normal levels of mRNA transcripts. Like the psbO deletion strain, the MSP-C20S mutant exhibits impaired O2 evolution activity and a greater stability of the S2 state as measured by thermoluminescence. Mutation of strictly conserved aspartate 159 to asparagine (MSP-D159N) does not affect the accumulation of MSP, but causes a reduction in the H2O-oxidation activity and thermoluminescence properties intermediate between the wild-type and the psbO deletion strain. In addition, we report upon improved methods for obtaining oxygen-evolving membranes from mutant cells.

Aspartic Acid↗

[Measurement of cerebral blood flow in normal subjects by phase contrast MR imaging].

Global cerebral blood flow (CBF) was quantitatively measured with a two-dimensional phase contrast cine magnetic resonance (MR) imaging technique in 24 normal subjects (mean age, 38.6 years; range, 12-70 years). Cine transverse images of the upper cervical region (32 phases/cardiac cycle) were acquired with a 1.5 Tesla MR imaging unit. In five subjects, measurement of CBF was performed before and after intravenous administration of acetazolamide (DIAMOX, 15 mg/kg). Inter- and intraobserver variations in flow volume measurement were small (r = 0.970, standard error of the estimate (SEE) = 2.9 ml/min, n = 80; r = 0.963, SEE = 4.6 ml/min, n = 40, respectively). In measuring flow velocity, they were inferior to those of flow volume measurement. On a visually determined setting of region of interest (ROI), reproducibly of the measurement of flow velocity was not satisfactory in this study. Thus only the results of flow volume measurement are presented. Mean summed vertebral flow volume (171 ml/min, SD = 40.6) was significantly less than mean summed internal carotid flow volume (523 ml/min, SD = 111). Total blood flow volume showed a significant decline with age (r = 0.45, p < 0.05). The mean proportions of carotid and vertebral flow volume to total flow volume were 75.3% and 24.7%, respectively, and showed no significant change with age. The left-to-right ratio of vertebral flow volume (1.39) was significantly higher than that of internal carotid flow volume (0.99, r = 0.05). After DIAMOX i.v., the mean rate of increase in total flow volume was 157%. Mean rates of increase in carotid and vertebral flow volume were 154% and 166%, respectively, which were not significantly different. In conclusion, this method is useful for estimating carotid and vertebral flow volume.

Acetazolamide↗

Functional characterization of mutant strains of the cyanobacterium Synechocystis sp. PCC 6803 lacking short domains within the large, lumen-exposed loop of the chlorophyll protein CP47 in photosystem II.

Several autotrophic mutant strains of Synechocystis sp. PCC 6803 carrying short deletions or a single-site mutation within the large, lumen-exposed loop (loop E) of the chlorophyll a-binding photosystem II core protein, CP47, are analyzed for their functional properties by measuring the flash-induced pattern of thermoluminescence, oxygen yield, and fluorescence quantum yield. A physiological and biochemical characterization of these mutant strains has been given in two previous reports [Eaton-Rye, J.J., & Vermaas, W.F.J. (1991) Plant Mol. Biol. 17, 1165-1177; Haag, E., Eaton-Rye, J.J., Renger, G., & Vermaas, S. F.J. (1993) Biochemistry 32, 4444-4454]. The results of the present study show that deletion of charged and conserved amino acids in a region roughly located between residues 370 and 390 decreases the binding affinity of the extrinsic PS II-O protein to photosystem II. Marked differences with PSII-O deletion mutants are observed with respect to Ca2+ requirement and the flash-induced pattern of oxygen evolution. Under conditions where a sufficient light activation is provided, the psbB mutants assayed in this study reveal normal S-state parameters and lifetimes. The results bear two basic implications: (i) the manganese involved in water oxidation can still be bound in a functionally normal or only slightly distorted manner, and (ii) the binding of the extrinsic PS II-O protein to photosystem II is impaired in mutants carrying a deletion in the domain between residues 370 and 390, but the presence of the PS II-O protein is still of functional relevance for the PS II complex, e.g., for maintenance of a high-affinity binding site for Ca2+ and/or involvement during the process of photoactivation.

Binding Sites↗

New hapten-protein conjugation method using N-(m-aminobenzoyloxy) succinimide as a two-level heterobifunctional agent: thyrotropin-releasing hormone as a model peptide without free amino or carboxyl groups.

The use of a two-level heterobifunctional agent N-(m-aminobenzoyloxy)succinimide (m-ABS) allowed us to develop a new method for preparing hapten-protein conjugates. This was demonstrated by a conjugation between thyrotropin-releasing hormone (TRH) and bovine or human serum albumin (BSA or HSA). The conjugation is based on the principle that the succinimidyl ester group of m-ABS immediately acts on an epsilon-amino group of lysine residues of carrier protein BSA (or HSA) and a m-aminobenzoyl group incorporated into the protein is then activated by diazotization to a functional m-diazobenzoyl group (m-DB) acting on a histidyl group of TRH. The TRH-BSA containing about 3.5 mol of TRH per BSA molecule, elicited the production of TRH antibody in rabbits. A new type of enzyme-linked immunosorbent assay (ELISA) for TRH was developed using the antiserum, the solid-phase antigen TRH-HSA and the commercially available horseradish peroxidase-labeled goat anti-rabbit IgG/Fab' as a marker, revealing that the ELISA was monospecific to the hormone and measured as low as 50 pg of the hormone reproducibly. Also, using the antiserum by the indirect immunoperoxidase method the distribution of immunoreactive TRH in the rat brain was demonstrated in neurons of the paraventricular nucleus and neuronal processes of the median eminence. These results strongly suggested that the use of m-ABS provided a simple and efficient new method for preparing immunogens not only for the previously reported haptens with a primary amino group(s) (J. Immunol. Methods 134 (1990) 227), but also for haptens with an imidazole, phenolic, or indole group(s) in the molecule.

Amino Acid Sequence↗

Identification of polysialic acid-containing glycoprotein in the jelly coat of sea urchin eggs. Occurrence of a novel type of polysialic acid structure.

Sea urchin eggs are surrounded by a gelatinous layer (called the jelly coat) that consists of mixture of fucoserich polysaccharides and sialic acid-rich glycoproteins. Chemical and 500 MHz 1H NMR spectroscopic studies revealed for the first time the presence of a novel polysialic acid (polySia) structure in the jelly coat glycoproteins isolated from Hemicentrotus pulcherrimus (designated polySia-gp(H)). The structure of the polySia chains was thoroughly characterized as (-->5-Oglycolyl-Neu5Gc alpha 2-->)n, where n ranges from 4 to more than 40 Neu5Gc residues. The polyNeu5Gc chains were attached to core oligosaccharides that were O-glycosidically linked to threonine residues on a core polypeptide. Each polypeptide contained about 17 O-linked polysialylglycan chains. The apparent molecular weight of polySia-gp(H) was 180,000. The expression of this new polySia structure in place of alpha 2-->8-linked polySia is the main structural feature that distinguishes polySia-gp from other known polysialylated glycoproteins. The (-->5-Ogly-colyl-Neu5Gc alpha 2-->)n chains were resistant to exo- and endosialidases from Arthrobacter ureafaciens and bacteriophage K1F, respectively. Discovery of these (-->5-Ogly-colyl-Neu5Gc alpha 2-->)n chains adds a new class of naturally occurring polySia to the structurally diverse family of polysialylated glycoproteins. The structure of a poly-Sia-gp from a different sea urchin species, Stronglyocentrotus purpuratus (designated polySia-gp(S)), was also determined to ascertain if there were any species-specific differences. The 500 MHz 1H NMR spectra of the two polySia-gps were identical, indicating that at this level of molecular detail the structures were the same. The molecular weight of polySiagp(S) was larger, however (250,000), and it contained about 25 polySia chains O-glycosidically linked to both threonine (two-thirds) and serine (one-third) residues.

Amino Acids↗

Discovery of a new type of sialidase, "KDNase," which specifically hydrolyzes deaminoneuraminyl (3-deoxy-D-glycero-D-galacto-2-nonulosonic acid) but not N-acylneuraminyl linkages.

The release of 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN, deaminoneuraminic acid) residues from their alpha-ketosidic linkage is required to determine the structural and functional role of KDN-glycoconjugates in sources as disparate as trout egg polysialoglycoproteins and human cancers. We report for the first time the isolation and characterization of a novel type of sialidase (KDNase), which specifically hydrolyzes KDN ketosidic but not N-acylneuraminyl linkages. KDNase activity was assayed using 4-methylumbelliferyl KDN (4-MU-KDN). A KDNase-producing microorganism was identified as Sphingobacterium multivorum. The affinity-purified enzyme was designated KDNase SM to denote its origin and that it was free of N-acylneuraminidase, proteolytic, and other glycosidase activities. KDNase SM activity toward 4-MU-KDN was not inhibited by the N-acylneuraminidase inhibitor, 2,3-dehydro-2-deoxy-N-acetylneuraminic acid. KDNase SM released free KDN from naturally occurring substrates, including (KDN)GM3, KDN-glycoprotein, which bears a number of O-linked chains of KDN alpha 2-->3Gal beta 1-->3GalNAc alpha 1-->3 (KDN alpha 2-->(-->8KDN alpha 2-->)n-->6)GalNAc alpha 1-->, and the biantennary complex-type of N-glycan, KDN alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6(KDN alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->3)Man beta 1-->4GlcNAc beta 1-->4GlcNAc. KDNase SM thus exhibited a broad linkage specificity and was able to hydrolyze the KDN residues ketosidically linked alpha 2-->3, alpha 2-->6, and alpha 2-->8. The enzyme did not release Neu5Ac or Neu5Gc from 4-MU-Neu5Ac, N-acetyl-neuraminyllactose, colominic acid, or other Sia(Neu5Ac or Neu5Gc)-containing glycoconjugates.

Bacteria↗

Synthesis and antibacterial activity of thiazolopyrazine-incorporated tetracyclic quinolone antibacterial agents. 2.

A novel series of 8-(2-substituted morpholino)-9,1-[(N-methylimino) methano]-7-fluoro-5-oxo-5H-thiazolo[3,2-a]quinoline-4-carboxylic acids, designated 8a-j, with a unique tetracyclic structure were synthesized, and the in vitro and in vivo antibacterial activities against Gram-positive strains, including methicillin-resistant Staphylococcus aureus isolates (MRSA), and Gram-negative strains were evaluated. These morpholino derivatives, 8a-j, showed excellent in vitro antibacterial activities against Gram-positive bacteria. The substitutions at the C-2 position of the 8-morpholino moiety of compound 8 play an important role in the enhancement of in vivo antibacterial activity. The unsubstituted morpholino derivative 8a, the 2,6-dimethyl derivative 8c, and the 2-ethylmorpholino derivative 8d showed poor in vivo antibacterial activity, while 8b, 8f-h, and 8j exhibited good activities. The 2-(methoxymethyl)morpholino derivative, 8h, showed the most potent activity in vivo. The therapeutic effects of 8h on systemic infection against S. aureus IID 803 were over 10-fold more potent than that of ofloxacin. Compound 8h, which showed superior oral bioavailability, has a chiral center. The enantiomers of 8h were synthesized, and the in vitro and in vivo antibacterial activities were evaluated. Both enantiomers, (S)-8h and (R)-8h, and the racemic compound 8 exhibited similar activities in vitro and in vivo. Compounds 8b and 8f-h also showed good levels of antibacterial activity against MRSA strains. The morpholino derivatives with unique tetracyclic structures are characterized by strong antibacterial activities against MRSA strains.

4-Quinolones↗

Light activation of expression associated with the tomato rbcS promoter in transformed tobacco cell line BY-2.

The promoter (2.3 kb) of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (rbcS3B) from tomato was inserted into the upstream multi-cloning site of beta-glucuronidase (GUS) gene. The construction was introduced into the tobacco suspension cultured cell, BY-2. The transformed tobacco cell exhibited greater GUS activity (10-fold) under the light condition than the dark condition. The specific GUS activity increased with increasing culture time under the light condition. In fed-batch culture, high density culture was achieved, 47.6 g l-1 dry weight, which was 6.8-fold greater than the batch culture, whereas the GUS was produced 1.7-fold in specific activity compared with the batch culture. Growth of BY-2 and GUS gene expression during the culture were simulated by a kinetic model.

Base Sequence↗

Distinct spatiotemporal distributions of the N-methyl-D-aspartate receptor channel subunit mRNAs in the mouse cervical cord.

The distribution of five N-methyl-D-aspartate (NMDA) receptor channel subunit mRNAs in the mouse spinal cord from embryonic day 13 (E13) through postnatal day 56 (P56) was semiquantitatively examined at the cervical level via in situ hybridization with subunit-specific oligonucleotide probes. Signals for the epsilon 1 subunit mRNA were restricted to the most ventral portion of the spinal cord during embryonic stages. They extended to all laminae of the spinal cord except for the lamina 2 (substantia gelatinosa) during postnatal development. A wide expression of the epsilon 2 subunit mRNA was found in the spinal gray matter from E13 through neonatal stages, but the signals became restricted to the lamina 2 by P21. No significant signals for the epsilon 3 subunit mRNA were detected in the spinal cord at any developmental stages. The epsilon 4 subunit mRNA was distributed widely in the spinal cord during embryonic and early postnatal periods but decreased nearly to background levels by P21. In contrast to the differential distribution of the epsilon subunit mRNAs, the zeta 1 subunit mRNA was found ubiquitously at each developmental stage examined. These findings suggest that the molecular organization of the epsilon subunits may be different between the dorsal horn and the remaining regions in the mature spinal cord, which provides a molecular basis for functional heterogeneity of the NMDA receptor channel. Moreover, this spatial heterogeneity might be generated through drastic alterations in the subunit composition of the channel complex during spinal cord development.

Animals↗

Isolation, structural determination, and calcium-binding properties of the major glycoprotein present in Bufo japonicus japonicus egg jelly.

Although the previous studies showed that the jelly coat is essential in anuran fertilization under natural conditions, identification and structural studies of the macromolecules that play functional roles have remained to be elucidated. In the present study we isolated acidic glycoproteins (JGP) from the solubilized egg jelly of Bufo japonicus japonicus, and showed that they were the major non-dialyzable macromolecular components of the jelly coat. JGP was a typical mucin-type glycoprotein, and it showed high degree of polydispersity in molecular masses ranging over 100-4000 kDa, but both amino acid and carbohydrate compositions were practically identical among fractions, suggesting that JGP was composed of a repeating glycoprotein unit. Four types of short O-glycan chains were isolated from JGP by reductive beta-elimination and their structures were determined as: Gal beta 1-->3[NeuAc alpha 2-->6]GalNAcol (= N-acetylgalactosaminitol), Fuc alpha 1-->2Gal beta 1-->3 [NeuAc alpha 2-->6]GalNAcol, Fuc alpha 1-->2Gal beta 1-->3[GlcNAc beta 1-->6]GalNAcol, and Fuc alpha 1-->2Gal beta 1-->3-GalNAcol. These carbohydrate units (about 80% of the mass of JGP) were linked to nearly all the serine and threonine residues which accounted for 55% of total amino acid residues. The Ca(2+)-binding property of JGP was studied by equilibrium dialysis. The high Ca(2+)-binding capacity of JGP was abolished by its desialylation of JGP and was highly dependent on the JGP concentration. When the low JGP concentrations as in the hydrated Bufo jelly were used, a 50% increment of both n (the number of binding sites) and Kd (the dissociation constant of JGP-Ca2+) values was observed. This property of JGP is suited to retaining Ca2+ and keeping its concentration at that just necessary for fertilizing sperm.

Animals↗