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Y Inoue

Publications and source records attributed to Y Inoue.

At least 127 records · Page 7Linked to original sources
PubMed2001

Unique fluorescence behavior of rhodamine B upon inclusion complexation with novel bis(beta-cyclodextrin-6-yl) 2,2'-bipyridine-4,4'-dicarboxylate.

Newly synthesized bis(beta-cyclodextrin-6-yl) 2,2'-bipyridine-4,4'-dicarboxylate was found to induce an unusual fluorescence enhancement of Rhodamine B (RhB) upon complexation. This effect is attributable to the equilibium shift of RhB to the highly fluorescent carboxylate ion form, which is induced by the cooperative binding by two appropriately preorganized cyclodextrin units in the bis(beta-cyclodextrin). This sandwich complexation behavior was investigated by means of the fluorescence and 2D NMR spectroscopy.

Cyclodextrins↗
PubMed2001

Developmental profile of neural cell adhesion molecule glycoforms with a varying degree of polymerization of polysialic acid chains.

More precise information on the degree of polymerization (DP) of polysialic acid (polySia) chains expressed on neural cell adhesion molecule (NCAM) and its developmental stage-dependent variation are considered important in understanding the mechanism of regulated polysialylation and fine-tuning of NCAM-mediated cell adhesion by polySia. In this paper, first we performed a kinetic study of acid-catalyzed hydrolysis of polySia and report our findings that (a) in (-->8Neu5Ac alpha 2-->)(n)-->8Neu5Ac alpha 2-->3Gal beta 1-->R, the proximal Neu5Ac residue alpha 2-->3 linked to Gal is cleaved about 2.5-4 times faster than the alpha 2-->8 linkages and (b) in contrary to general belief that alpha 2-->8 linkages in polySia are extremely labile, the kinetic consideration showed that they are not so unstable, and every ketosidic bond is hydrolyzed at the same rate. These findings are the basis of our strategy for DP analysis of polySia on NCAM. Second, using the recently developed method that provides base-line resolution of oligo/polySia from DP 2 to >80 with detection thresholds of 1.4 fmol per resolved peak, we have determined the DP of polySia chains expressed in embryonic chicken brains at different developmental stages. Our results support the presence of numerous NCAM glycoforms differing in DPs of oligo/polySia chains and a delicate change in their distribution during development.

Animals↗
PubMed2001

Molecular design and synthesis of artificial ion channels based on cyclic peptides containing unnatural amino acids.

A series of novel cyclic peptides composed of 3 to 5 dipeptide units with alternating natural-unnatural amino acid units, have been designed and synthesized, employing 5-(N-alkanoylamino)-3-aminobenzoic acid with a long alkanoyl chain as the unnatural amino acid. All cyclic peptides with systematically varying pore size, shape, and lipophilicity are found to form ion channels with a conductance of ca. 9 pS in aqueous KCl (500 mM) upon examination by the voltage clamp method. These peptide channels are cation selective with the permeability ratio P(Cl(-))/P(K(+)) of around 0.17. The ion channels formed by the neutral, cationic, and anionic cyclic peptides containing L-alanine, L-lysine, and L-aspartate, respectively, show the monovalent cation selectivity with the permeability ratio P(Na(+))/P(K(+)) of ca. 0.39. On the basis of structural information provided by voltage-dependent blockade of the single channel current of all the tested peptides by Ca(2+), we inferred that each channel is formed from a dimer of the peptide with its peptide ring constructing the channel entrance and its alkanoyl chains lining across the membrane to build up the channel pore. The experimental results are consistent with an idea that the rate of ion conduction is determined by the nature of the hydrophobic alkanoyl chain region, which is common to all the channels.

Amino Acid Sequence↗
PubMed2001

Idiopathic spinal cord herniation associated with intervertebral disc extrusion: a case report and review of the literature.

STUDY DESIGN: A case of idiopathic spinal cord herniation is reported, and the literature is reviewed. OBJECTIVE: To report a case of thoracic spinal cord herniation with a ventral dural defect, probably caused by thoracic disc extrusion. SUMMARY OF BACKGROUND DATA: Recently, reports of spinal cord herniation have been increasing. This increase can be attributed to the development of magnetic resonance imaging and increased awareness of this entity. However, the cause of the ventral dural defect remains unknown. METHODS: A 54-year-old woman had experienced Brown-Séquard syndrome for 2 years. Magnetic resonance imaging demonstrated an S-shaped anterior kinking of the spinal cord, with dilation of the dorsal subarachnoid space. RESULTS: After incision of the dural sac and gentle retraction of the spinal cord, a dural defect was recognized into which the spinal cord had herniated. An extruded disc was visualized through the defect at T3-T4. The ventral dural defect and the dorsal incision of the dural sac were repaired with a fascial graft from the thigh. CONCLUSIONS: Intraoperative findings suggest that the thoracic disc herniation in the current case was the probable cause of the ventral dural defect. Surgical reconstruction using double fascial graft under careful spinal cord monitoring resulted in a satisfactory neurologic recovery.

Brown-Sequard Syndrome↗
PubMed2001

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S).

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

Journal Article↗
PubMed2001

Relationship between Taq1 A dopamine D2 receptor (DRD2) polymorphism and prolactin response to bromperidol.

The dopamine D2 receptor (DRD2) gene has a Taq1 A restriction fragment length polymorphism yielding two alleles, A1 and A2. We have previously shown that female patients with the A1 allele show greater prolactin response to nemonapride, a selective antagonist for D2-like dopamine receptors, in schizophrenic patients. In the present study, the relationship between this polymorphism and prolactin response to bromperidol was investigated in 32 untreated schizophrenic inpatients (16 males, 16 females). The daily dose of bromperidol was fixed at 6 (n = 10), 12 (n = 13), or 18 mg (n = 9) during a 2-week treatment period. Taq1 A genotypes were determined by PCR method. Plasma prolactin concentration was measured by radioimmunoassay. Plasma concentration of bromperidol was measured by HPLC method. The subjects were divided into four subgroups by gender and the genotypes, i.e., 10 males and 11 females with the A1 allele, 6 males and 5 females with no A1 allele. The females with the A1 allele had the highest Delta prolactin (the change from the pretreatment concentration)/bromperidol concentration ratio among the other groups (P < 0.05). The present study thus suggests that female patients with the A1 allele show greater prolactin response to bromperidol, who may have a high risk for adverse effects associated with neuroleptic-induced hyperprolactinemia.

Adult↗
PubMed2001

Supramolecular chirogenesis in zinc porphyrins: mechanism, role of guest structure, and application for the absolute configuration determination.

The achiral syn folded (face-to-face conformation) host molecule of the ethane-bridged bis(zinc porphyrin) transforms into the corresponding chiral extended anti bis-ligated species in the presence of enantiopure amine guests. The mechanism of the supramolecular chirogenesis is based upon the screw formation in bis(zinc porphyrin), arising from steric interactions between the largest substituent at the ligand's asymmetric carbon and peripheral alkyl groups of the neighboring porphyrin ring pointing toward the covalent bridge. The screw direction is determined by the guest's (amines) absolute configuration resulting in a positive chirality induced by (S)-enantiomers due to formation of the right-handed screw, and a negative chirality produced by the left-handed screw of (R)-enantiomers. The screw magnitude is strongly dependent upon the structure of the chiral guests. The amines with bulkier substituents result in stronger CD signals and larger (1)H NMR resonance splittings of enantiotopic protons. This system possesses a high degree of chiroptical activity, which allows the differentiation of one of the smallest homologous elements of organic chemistry, that is, the methyl and ethyl groups attached to the asymmetric carbon, and additionally, which senses a remote chiral center at a position beta to the amine binding group.

Circular Dichroism↗
PubMed2001

Two functionally distinct manganese clusters formed by introducing a mutation in the carboxyl terminus of a photosystem II reaction center polypeptide, D1, of the green alga Chlamydomonas reinhardtii.

To study the function of the carboxyl-terminal domain of a photosystem II (PSII) reaction center polypeptide, D1, chloroplast mutants of the green alga Chlamydomonas reinhardtii have been generated in which Leu-343 and Ala-344 have been simultaneously or individually replaced by Phe and Ser, respectively. The mutants carrying these replacements individually, L343F and A344S, showed a wild-type phenotype. In contrast, the double mutant, L343FA344S, evolved O2 at only 20-30% of the wild-type rate and was unable to grow photosynthetically. In this mutant, PSII accumulated to 60% of the wild-type level, indicating that the O2-evolving activity per PSII was reduced to approximately half that of the wild-type. However, the amount of Mn atom detected in the thylakoids suggested that a normal amount of Mn cluster was assembled. An investigation of the kinetics of flash-induced fluorescence yield decay revealed that the electron transfer from Q(-)(A) to Q(B) was not affected. When a back electron transfer from Q(-)(A) to a donor component was measured in the presence of 3-(3,4-dichlorophenol)-1,1-dimethylurea, a significantly slower component of the Q(-)(A) oxidation was detected in addition to the normal component that corresponds to the back electron transfer from the Q(-)(A) to the S(2)-state of the Mn cluster. Thermoluminescence measurements revealed that L343FA344S cells contained two functionally distinct Mn clusters. One was equivalent to that of the wild-type, while the other was incapable of water oxidation and was able to advance the transition from the S(1)-state to the S(2)-state. These results suggested that a fraction of the Mn cluster had been impaired by the L343FA344S mutation, leading to decreased O2 evolution. We concluded that the structure of the C-terminus of D1 is critical for the formation of the Mn cluster that is capable of water oxidation, in particular, transition to higher S-states.

Animals↗
PubMed2001

The Zrc1 is involved in zinc transport system between vacuole and cytosol in Saccharomyces cerevisiae.

The ZRC1 gene encodes a multicopy suppressor of zinc toxicity in Saccharomyces cerevisiae; however, previously we found that the expression of ZRC1 was induced when the intracellular zinc level was decreased. Zrc1 has six putative transmembrane domains and we determined that a Zrc1-GFP fusion protein was localized to the vacuolar membrane. The steady state level of intracellular zinc in a zrc1Delta mutant cultured in the zinc-abundant medium was lower than that in wild type. No distinct difference was observed in the basal activity of glyoxalase I, which is a cytosolic enzyme requiring zinc for catalytic function and is used here as a marker for cytosolic zinc-availability, between wild type and zrc1Delta mutant, although the activity was decreased much greater extent in the zrc1Delta mutant if the cells were exposed to the metal-limited medium. Similarly, the basal expression level of ZRC1-lacZ reporter gene in zrc1Delta mutant was the same as that in wild type; however, the fold of induction of ZRC1-lacZ expression in zrc1Delta mutant under the zinc-limited conditions was higher than that in the wild type. Based on these results, we present a tentative model for the function of Zrc1 as a mechanism to maintain the zinc homeostasis in yeast.

Base Sequence↗
PubMed2001

Mechanism of pH-dependent photolysis of aliphatic amino acids and enantiomeric enrichment of racemic leucine by circularly polarized light.

It has been proposed that the origin of biological homochirality may be the result of irradiation of a racemic sample of amino acids by circularly polarized light (CPL). To determine the mechanism of enantiomeric enrichment, the irradiation of aliphatic amino acids by CPL was undertaken. An enantiomerically enriched sample (e.g., L isomer enrichment from r-CPL) was found to result from the preferential excitation/decomposition of one enantiomer over another via a Norrish Type II mechanism (leucine, valine, and isoleucine), with the enantiomeric excess dependent on the degree of protonation of the amino/carboxylic acid moiety.

Amino Acids↗
PubMed2001

Measurement of the CP violation parameter sin2 phi(1) in B(0)(d) meson decays.

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

Journal Article↗
PubMed2001

Effect of dissolved oxygen concentration in the fermentation medium on transformation of the carbon sources during the biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxypropionate) by Alcaligenes latus.

Effects of fermentation conditions on the comonomer composition and its distribution of poly(3-hydroxybutyrate-co-3-hydroxypropionate) [P(3HB-co-3HP)] have been investigated for bacterial synthesis of P(3HB-co-3HP)s by Alcaligenes latus from sucrose and 3-hydroxypropionate (3HPA) mixed carbon sources. Comparison of the microstructures of these samples drew a conclusion that when the concentration of oxygen dissolved (DO) in the fermentation medium was controlled between 5 and 20% (based on the concentration at saturation), the 3HP content and the comonomer compositional distribution (CCD) of the copolymer would not be influenced by the DO values. The concentration of the carbon sources was monitored during the fermentation. The results indicated that the comonomer composition and its distribution of P(3HB-co-3HP)s were interrelated to the amounts of carbon sources transported into the bacterial cells. When the bacteria consumed more sucrose, the more 3HPA they would utilize, and the broader the CCD of the copolymer would be. Furthermore, the efficiencies of the transformation of the two carbon sources to the copolymer constituents were found to be similar.

Alcaligenes↗
PubMed2001

The crystal structure of the ttCsaA protein: an export-related chaperone from Thermus thermophilus.

The CsaA protein was first characterized in Bacillus subtilis as a molecular chaperone with export-related activities. Here we report the 2.0 Angstrom-resolution crystal structure of the Thermus thermophilus CsaA protein, designated ttCsaA. Atomic structure and experiments in solution revealed a homodimer as the functional unit. The structure of the ttCsaA monomer is reminiscent of the well known oligonucleotide-binding fold, with the addition of extensions at the N- and C-termini that form an extensive dimer interface. The two identical, large, hydrophobic cavities on the protein surface are likely to constitute the substrate binding sites. The CsaA proteins share essential sequence similarity with the tRNA-binding protein Trbp111. Structure-based sequence analysis suggests a close structural resemblance between these proteins, which may extend to the architecture of the binding sites at the atomic level. These results raise the intriguing possibility that CsaA proteins possess a second, tRNA-binding activity in addition to their export-related function.

Amino Acid Sequence↗
PubMed2001

Molecular cloning and functional expression of bottle-nosed dolphin (Tursiops truncatus) interleukin-1 receptor antagonist.

The bottle-nosed dolphin (Tursiops truncatus) interleukin-1 receptor antagonist IL-1ra cDNA was cloned from mitogen-stimulated peripheral blood mononuclear cells (PBMC) RNA utilizing the reverse transcription-polymerase chain reaction (RT-PCR). The sequence of this cDNA showed that dolphin IL-1ra clones contained open reading frames encoding 177 amino acids. Comparison of the deduced amino acids showed that dolphin IL-1ra sequence shared 87.6, 77.9, 77.4, 77.4, 76.4, and 75.8% similarity with the bovine, rabbit, equine, human, mouse, and rat IL-1ra sequences, respectively. Recombinant glutathione S-transferase (GST) dolphin IL-1ra produced in Escherichia coli (E. coli) was purified. This protein suppressed the cytostatic activity of dolphin IL-1beta on A375S2 cells, indicating that the dolphin IL-1ra cDNA obtained in the present study encodes biologically active dolphin IL-1ra.

Amino Acid Sequence↗
PubMed2001

Phosphatidylglycerol participates in syncytium formation induced by HTLV type 1-bearing cells.

We previously reported that 71-kDa heat shock cognate protein (HSC70) was expressed on the cell surface of human T cell lymphotropic virus type 1 (HTLV-1)-susceptible cells and that HSC70, beta-actin, and a lipid-like component on the target cell membrane participated in syncytium formation by HTLV-1. We have now identified this lipid-like component to be palmitoyl (16:0)-oleoyl (18:1)-phosphatidylglycerol (POPG), using preparative thin-layer chromatographic fractionation and tandem mass spectrometric analysis. In the syncytium formation assay, exogenously added PG inhibited cell-to-cell transmission of HTLV-1 in a dose-dependent manner. Other phospholipids showed less (PE) or no effect (PC, PS, PI, PA, lysoPC, lysoPE, and CL). Binding experiments showed that PG interacted with three synthetic peptides, gp46--111, gp46--197, and gp21--400, which correspond to regions Lys111--Asp138 and Asp197--Leu216 on the gp46 surface glycoprotein, and to region Cys400--Leu429 on the gp21 transmembrane glycoprotein, respectively, as well as with intact gp46 and gp21 proteins of HTLV-1. On the other hand, HSC70 and beta-actin interacted with gp46--197 and gp46, not with gp46--111. However, the eluate from an affinity column coupled with gp46--111 contained not only PG but also HSC70 and beta-actin, despite the lack of direct interaction between gp46--111 and these proteins. In the in vitro binding assay, HSC70 showed interaction with both PG and beta-actin, while there was no evidence of any interaction between PG and beta-actin. These results suggest that HSC70 molecules on target cell surface interact with both PG in lipid bilayers and intracellular beta-actin and that these three cellular components form a receptor complex that plays a critical role in syncytium formation induced by HTLV-1-bearing cells.

Actins↗
PubMed2001

A unique sialidase that cleaves the Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc linkage: comparison of its specificity with that of three microbial sialidases toward four sialic acid dimers.

We found that the hepatopancreas of oyster, Crassostrea virginica, contained a sialidase capable of releasing Neu5Gc from the novel polysialic acid chain (-->5-O(glycolyl)Neu5Gcalpha2-->)n more efficiently than from the conventional type of polysialic acid chains, (-->8Neu5Acalpha2-->)n, or (-->8Neu5Gcalpha2-->)n. We have partially purified this novel sialidase and compared its reactivity with that of microbial sialidases using four different sialic acid dimers, Neu5Gcalpha2-->5-O(glycolyl)Neu5Gc (Gg2), Neu5Acalpha2-->8Neu5Ac (A2), Neu5Gcalpha2-->8Neu5Gc (G2), and KDNalpha2-->8KDN (K2) as substrates. Hydrolysis was monitored by high performance anion-exchange chromatography with a CarboPac PA-100 column and pulsed amperometric detection, the method by which we can accurately quantitate both the substrate (sialiac acid dimers) and the product (sialic acid monomers). The oyster sialidase effectively hydrolyzed Gg2 and K2, whereas A2 and G2 were poor substrates. Neu5Ac2en but not KDN2en effectively inhibited the hydrolysis of Gg2 by the oyster sialidase. Likewise, the hydrolysis of K2 by the oyster sialidase was inhibited by a cognate inhibitor, KDN2en, but not by Neu5Ac2en. Using the new analytical method we found that Gg2 was hydrolyzed less efficiently than A2 but much more readily than G2 by Arthrobacter ureafaciens sialidase. This result was at variance with the previous report using the thiobarbituric acid method to detect the released free sialic acid [Kitazume, S., et al. (1994) Biochem. Biophys. Res. Commun. 205, 893-898]. In agreement with previous results, Gg2 was a poor substrate for Clostridium perfringens sialidase, while K2 was refractory to all microbial sialidases tested. Thus, the oyster sialidase is novel and distinct from microbial sialidases with regards to glycon- and linkage-specificity. This finding adds an example of the presence of diverse sialidases, in line with the diverse sialic acids and sialic acid linkages that exist in nature. The new sialidase should become useful for both structural and functional studies of sialoglycoconjugates.

Animals↗
PubMed2001

Molecular recognition studies on supramolecular systems. 32. Molecular recognition of dyes by organoselenium-bridged bis(beta-cyclodextrin)s.

A series of novel bis(beta-cyclodextrin)s tethered with organoselenium linkers, i.e., 6,6'-(o-phenylene-diseleno)-bridged bis(beta-cyclodextrin) (2), 6,6'-[2,2'-diselenobis(benzoyloxy)]-bridged bis(beta-cyclodextrin) (3), and 6,6'-[2,2'-diselenobis[2-(benzoylamino)ethylamino]]-bridged bis(beta-cyclodextrin) (4), were synthesized from beta-cyclodextrin (1). The inclusion complexation behavior of 1-4 with some dyes, such as 8-anilinonaphthalenesulfonate (ANS), Brilliant Green, Crystal Violet, Tropaeolin OO, Auramine O, and Methyl Orange, was investigated in aqueous phosphate buffer solution (pH 7.20) at 25 degrees C by UV-vis, fluorescence, and circular dichroism spectrometry, as well as fluorescence lifetime measurements. The complex stability constants (Ks) and Gibbs free energy changes (delta Go) for the stoichiometric 1:1 inclusion complexation of 1-4 with the dyes were obtained by the spectrophotometric or spectropolarimetric titrations. The bis(beta-cyclodextrin)s 2-4 showed much higher affinities toward these guest dyes than native beta-cyclodextrin 1 with fairly good molecular selectivities. The cooperative binding abilities of these bis(beta-cyclodextrin)s are discussed from the viewpoints of size/shape-fit interaction, induced-fit concept, and multiple recognition mechanism.

Journal Article↗