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H Taira

Publications and source records attributed to H Taira.

At least 19 recordsLinked to original sources
PubMed2000

A covariant change of the two highly conserved bases in the GTPase-associated center of 28 S rRNA in silkworms and other moths.

The GTPase-associated center in 23/28 S rRNA is one of the most conserved functional domains throughout all organisms. We detected a unique sequence of this domain in Bombyx mori species in which the bases at positions 1094 and 1098 (numbering from Escherichia coli 23 S rRNA) are C and G instead of the otherwise universally conserved bases U and A, respectively. These changes were also observed in four other species of moths, but not in organisms other than the moths. Characteristics of the B. mori rRNA domain were investigated by native polyacrylamide gel electrophoresis using RNA fragments containing residues 1030-1128. Although two bands of protein-free RNA appeared on gel, they shifted to a single band when bound to Bombyx ribosomal proteins Bm-L12 and Bm-P complex, equivalent to E. coli L11 and L8, respectively. Bombyx RNA showed lower binding capacity than rat RNA for the ribosomal proteins and anti-28 S autoantibody, specific for a folded structure of the eukaryotic GTPase-associated domain. When the C(1094)/G(1098) bases in Bombyx RNA were replaced by the conserved U/A bases, the protein-free RNA migrated as a single band, and the complex formation with Bm-L12, Bm-P complex, and anti-28 S autoantibody was comparable to that of rat RNA. The results suggest that the GTPase-associated domain of moth-type insects has a labile structural feature that is caused by an unusual covariant change of the U(1094)/A(1098) bases to C/G.

Animals↗
PubMed2000

Identification and characterization of cell lines with a defect in a post-adsorption stage of Sendai virus-mediated membrane fusion.

In the early stage of infection, Sendai virus delivers its genome into the cytoplasm by fusing the viral envelope with the cell membrane. Although the adsorption of virus particles to cell surface receptors has been characterized in detail, the ensuing complex process that leads to the fusion between the lipid bilayers remains mostly obscure. In the present study, we identified and characterized cell lines with a defect in the Sendai virus-mediated membrane fusion, using fusion-mediated delivery of fragment A of diphtheria toxin as an index. These cells, persistently infected with the temperature-sensitive variant Sendai virus, had primary viral receptors indistinguishable in number and affinity from those of parental susceptible cells. However, they proved to be thoroughly defective in the Sendai virus-mediated membrane fusion. We also found that viral HN protein expressed in the defective cells was responsible for the interference with membrane fusion. These results suggested the presence of a previously uncharacterized, HN-dependent intermediate stage in the Sendai virus-mediated membrane fusion.

Animals↗
PubMed2000

Properties of tofus and soy milks prepared from soybeans having different subunits of glycinin.

The contribution of soybean protein to the physical properties of tofu, a product manufactured by curdling soy milk with coagulants such as calcium or magnesium chloride, was studied by comparing the properties of soy milk prepared from soybeans with different subunits (I, IIa, and IIb) of glycinin with amino acid residues deleted. The breaking stress value of the tofu curds prepared from soybeans having group I was higher than those without group I. The soy milks having group I contained more protein particles and showed more sensitivity to calcium and magnesium ions than those without group I. The amounts of glycinin and protein particles were higher in the soy milks having group I than those in the soy milks without group I. To elucidate the influence of each group on the breaking stress, the glycinin content was adjusted to an identical level in soy milks having each group. Among the tofu curds from three groups, their order of hardness according to their breaking stress was IIa, IIb, and I. The order of particle content among these soy milks was also IIa, IIb, and I. Therefore, the results suggested that the breaking stress value of the tofu curd is dependent upon the number of protein particles in the soy milk and that the number of the particles is determined by the proportion and structure of glycinin in the soybean.

Calcium Chloride↗
PubMed2000

Functional analysis of the individual oligosaccharide chains of sendai virus fusion protein.

The roles of N-linked glycosylation in the intracellular transport and fusion activity of the Sendai virus fusion (F) protein were studied. Each of three potential glycosylation motifs (designated g1, g2, and g3) in the F protein was mutated separately or in combination with the other sites. When the mutant F proteins were transiently expressed in COS cells, they showed significant changes in electrophoretic mobility, indicating that all three motifs in the F protein are glycosylated. Glycosylation-defective mutants which lacked the g2-oligosaccharide chain showed decreased immunoreactivity with a monoclonal antibody specific for the native conformation and were inefficiently transported to the cell surface. Such mutants, with the exception of a double mutant lacking g1 and g2-oligosaccharide chains, were also not able to induce syncytia formation when cells expressing them plus the hemagglutinin-neuraminidase protein were treated with trypsin. Mutations at the other glycosylation sites did not significantly affect the immunoreactivity with the monoclonal antibody or the efficiency of intracellular transport of the F protein. These results indicate that the N-linked oligosaccharide chain attached at g2 is important for efficient intracellular transport and for the fusion activity of the F protein.

Animals↗
PubMed2000

Substrate specificity analysis of microbial transglutaminase using proteinaceous protease inhibitors as natural model substrates.

The substrate specificity of microbial transglutaminase (MTG) from Streptomyces mobaraensis (formerly categorized Streptoverticillium) was studied using a Streptomyces proteinaceous protease inhibitor, STI2, as a model amine-donor substrate. Chemical modification and mutational analysis to address the substrate requirements for MTG were carried out around the putative reactive site region of STI2 on the basis of the highly refined tertiary structure and the solvent accessibility index of Streptomyces subtilisin inhibitor, SSI, a homolog of STI2. The results suggest that the P1 reactive center site (position 70 of STI2) for protease subtilisin BPN' or trypsin may be the prime Lys residue that can be recognized by MTG, when succinylated beta-casein was used as a partner Gln-substrate. It is characteristic in that the same primary enzyme contact region of STI2 is shared by both enzymes, MTG and proteases. For quantitative analysis of the TG reaction, we established an ELISA-based monitoring assay system using an anti-SSI polyclonal antibody highly cross-reactive with STI2. Site-specific STI2 mutants were prepared by an Escherichia coli expression-secretion vector system and subjected to the assay system. We reached several conclusions concerning the nature of the flanking amino acid residues affecting the MTG reactivity of the substrate Lys residue: (i) site-specific mutations from Asn to Lys or Arg at position 69 preceding the amine-donor 70Lys, led to enhanced substrate reactivity; (ii) amino acid replacement at 67Ile with Ser led to higher substrate reactivity, (iii) additive effects were obtained by a combination of the positive mutations at positions 67 and 69 as described above, and (iv) Gly at position 65 might be essential for MTG reaction. Moreover, the substrate specificity of guinea pig liver tissue transglutaminase (GTG) was compared with that of MTG using STI2 and its mutants. In contrast to MTG, replacement of Gly by Asp at position 65 was the most favorable for substrate reactivity. Also, 70Lys appeared not to be a prime amine-donor site for GTG-mediated cross-linking, suggesting a difference in substrate recognition between MTG and GTG.

Amino Acid Sequence↗
PubMed2000

MR appearance of paraganglioma of the cauda equina. Case reports.

PURPOSE: To investigate the value of MR imaging for preoperative diagnosis of paraganglioma of the cauda equina. MATERIAL AND METHODS: A retrospective review of 2 cases of paraganglioma of the cauda equina examined with MR imaging was undertaken. Features assessed included the homogeneity of the lesions, presence or absence of serpiginous flow void and thin hypointense margins. RESULTS: In case 1, the tumor was hyperintense on the postcontrast examination and serpiginous flow void suggested vessels in the upper pole of the tumor. In case 2, the tumor was encapsulated by a thin hypointense margin on both T1- and T2-weighted images, which suggested hemosiderin. CONCLUSION: The MR appearance may be of great value in the preoperative diagnosis of paraganglioma of the cauda equina.

Cauda Equina↗
PubMed1999

Modulation by L- and D-isoforms of amino acids of the L-glutamate response of N-methyl-D-aspartate receptors.

N-Methyl-D-aspartate (NMDA) receptor subtypes epsilon 1 and zeta 1 were coexpressed in Xenopus oocytes for the investigation of the magnitude of augmentation of the L-glutamate response by 20 common L-amino acids and their 19 D-isoforms. Simultaneous application of L- and D-alanine, -cysteine, and -serine, or glycine and L-glutamate potentiated the glutamate-induced current. Other amino acids produced only marginal effects. Analysis of the relationship between the response and amino acid size revealed that the critical threshold size is between those of cysteine and aspartate. No amino acid alone induced a current. The effects of L- and D-alanine, -cysteine, and -serine applied with L-glutamate were concentration-dependent. Molecular modeling of these three amino acids revealed a positive relationship between the charge at an atom of the side chain and the receptor sensitivity, which may explain the efficacies of these amino acids.

Alanine↗
PubMed1999

Extraosseous calcified plasmacytoma causing thoracic myelopathy.

We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis.

Amyloid↗
PubMed1999

Kinetics of interactions of sendai virus envelope glycoproteins, F and HN, with endoplasmic reticulum-resident molecular chaperones, BiP, calnexin, and calreticulin.

Sendai virus envelope glycoproteins, F and HN, mature during their transport through the endoplasmic reticulum (ER) and Golgi complex. To better understand their maturation processes in the ER, we investigated the time course of their interactions with three ER- resident molecular chaperones, BiP, calnexin (CNX), and calreticulin (CRT), in Sendai virus-infected HeLa cells. Pulse-chase and immunoprecipitation analyses using antibodies against each virus glycoprotein or ER chaperone revealed that F precursor interacted with CNX transiently (t(1/2)=8 min), while HN protein displayed longer and sequential interactions with BiP (t(1/2)=8 min), CNX (t(1/2)=15 min), and CRT (t(1/2)=20 min). HN interacted with the three ER chaperones not only as a monomer but also as a tetramer for several hours, suggesting mechanism(s) to undergo chaperone-mediated quality control of an assembled HN oligomer in the ER. The kinetics of dissociation of the HN-chaperone complexes exhibited a marked delay in the presence of proteasome inhibitors, suggesting that a part of HN associated with BiP, CNX, and CRT is destined to be degraded in the proteasome-dependent pathway. Further, the associations between virus glycoproteins and CNX or CRT were impaired by castanospermine, an inhibitor of ER glucosidase I and II, confirming that these interactions require monoglucosylated oligosaccharide on F(0) and HN peptides. These findings together suggest that newly synthesized F protein undergoes rapid maturation in the ER through a transient interaction with CNX, whereas HN protein requires more complex processes involving prolonged association with BiP, CNX, and CRT for its quality control in the ER.

Calcium-Binding Proteins↗
PubMed1999

Bipedicled submental island flap for upper lip reconstruction.

A case of reconstruction of the upper lip with a bipedicled submental flap is described. Although the mobility of the flap was restricted, the arterial blood supply was abundant by altering the single-pedicled flap into a bipedicled flap. This flap is a good color and texture match to the face, and surpasses other flaps in reconstruction of the mustache or beard in male patients.

Humans↗
PubMed1999

Immunoaffinity purification and identification of the molecular chaperone calnexin.

We have developed a method for the immunoaffinity purification of calnexin, an endoplasmic reticulum molecular chaperone, and analyzed the molecular weight of purified calnexin using matrix-assisted laser adsorption ionization time of flight mass spectrometry (MALDI TOF-MS). Calnexin was thereby found to have a molecular weight of 66.1 x 10(3), which is nearly identical to the molecular weight estimated from the protein sequence.

Calcium-Binding Proteins↗
PubMed1999

Expression of elongation factor 1 beta' in Escherichia coli and its interaction with elongation factor 1 alpha from silk gland.

Silk gland elongation factor 1 (EF-1) consists of four subunits: alpha, beta, beta', and gamma. EF-1 beta beta' gamma catalyzes the exchange of GDP for GTP on EF-1 alpha and stimulates the binding of EF-1 alpha-dependent aminoacyl-tRNA to ribosomes. The carboxy-terminal regions of the EF-1 beta subunits from various species are highly conserved. We examined the region of EF-1 beta' that binds to EF-1 alpha by in vitro binding assays, and examined the GDP/GTP exchange activity using deletion mutants of a GST-EF1 beta' fusion protein. We thereby suggested a pivotal amino acid region, residues 189-222, of EF-1 beta' for binding to EF-1 alpha.

Amino Acid Sequence↗
PubMed1998

Spread of swine hemagglutinating encephalomyelitis virus from peripheral nerves to the CNS.

Swine hemagglutinating encephalomyelitis virus (HEV) strain 67N was inoculated into the sciatic nerve or the right leg crural muscle of rats. In both cases, the virus was isolated first from the caudal half of the spinal cord on day 2 after inoculation, and from the rostral half of the spinal cord and the brain on day 3. The virus titers in the brain reached a maximum when the infected rats developed CNS symptoms on day 5. Using confocal laser scanning microscope, fluorescent positive cells were first found in the lumbar dorsal root ganglion (DRG) and spinal cord ipsilateral of the inoculated leg on day 3. Antigen positive neurons were found bilaterally in the lumbar DRG and spinal cord on day 4. On day 5 specific fluorescence was observed in the neurons of the cerebral cortex, hippocampus, brainstem and Purkinje cells in the cerebellum.

Animals↗
PubMed1998

The roles of individual cysteine residues of Sendai virus fusion protein in intracellular transport.

The role of intramolecular disulfide bonds in the fusion (F) protein of Sendai virus was studied. The 10 cysteine residues were changed to serine residues using site-directed mutagenesis. None of the cysteine mutant F proteins reacted with a monoclonal antibody specific for the mature conformation of the F protein, but eight of ten mutants reacted with an immature conformation-specific monoclonal antibody. The transport of these mutant proteins to the cell surface was drastically reduced. All of the cysteine mutant F proteins remained sensitive to endoglycosidase H (endo H) for 3 h after their synthesis. Moreover, cell surface transport of the hemagglutinin-neuraminidase (HN) protein co-expressed with each of these cysteine mutant F proteins was also reduced. These results suggest that all cysteine residues participate in the formation of intramolecular disulfide bonds, that co-translational disulfide bond formation is crucial to the correct folding and intracellular transport of the F protein, and that interaction of the F and HN proteins takes place intracellulary.

Animals↗
PubMed1997

[Comparison of predictive methods of Sugi (Cryptomeria) atmospheric pollen counts using mean temperature, solar radiation and male flowering index--an example of Toyama Prefecture].

The previous years mean temperature of July, total solar radiation of July and August and the male flowering index were used to predict atmospheric pollen counts. We examined the adaptability of these predictions and we get following results: 1. Following good harvest years of male flower, atmospheric pollen counts predicted by previous year's mean temperature of July and the total solar radiation of July and August are higher than the actual atmospheric pollen count. 2. Prediction of atmospheric pollen counts by factors within the previous five years are more exact because matured Cryptomeria forests are increasing yearly. 3. There are few errors in prediction by the flowering index because the flower index reflects the actual harvest of male flower.

Air↗
PubMed1997

Introducing a solid model for reconstructing the severely deformed hand.

We report a case of a 39-year-old man with a severely deformed hand resulting from an injury sustained in a traffic accident at 2 years of age. A Marjolin ulcer appeared on the cicatricial area 3 years ago. After radical surgery for squamous cell carcinoma, we planned to realign the axis of the ulnarly flexed hand. Prior to surgery, we produced a solid model of the bony framework using laser lithography based on 3-D CT digital image data. The solid model furnished us and the patient with precise information on the deformity and allowed us to perform preoperative simulation surgery. By a two-stage wedge-shaped ostectomy at the end of the radius, the ulnarly deviated axis of the hand was realigned from 100 to 30 degrees (approximate) in clinical measurement and the patient was quite satisfied with the resulting function and appearance. However, there are some disadvantages of the laser lithography solid model: the cost is high, the resin material is very hard and difficult to operate on, and the model does not include soft-tissue structures. The development of a model in the future that includes vessels, nerves, and tendons will enable surgeons to transfer more precisely the results of the simulation surgery to the patient in the operating room.

Adult↗
PubMed1996

Adsorbed serum protein mediated adhesion and growth behavior of bovine aortic endothelial cells on polyamine graft copolymer surfaces.

Polyamine-brushed substrata for cell culture were designed by solvent casting of polystyrene-graft-polyamine copolymer (SA) on hydrophobically modified glass surface, and adhesion, spreading, and proliferation of bovine aortic endothelial cells (BAEC) on these substrata were evaluated. Adhesion and spreading of BAEC increased with increasing polyamine content in the copolymer. Close correlation was found between cellular spreading and subsequent cell growth; the surface inducing better spreading of adhered cells showed higher endothelial cell growth. Adhesion and spreading of BAEC were significantly influenced by fetal calf serum (FCS)-pretreatment of the SA copolymer surfaces, being increased with increasing polyamine content, whereas on bovine serum albumin (BSA)-preabsorbed surfaces, BAEC adhesion was considerably prevented and eventually no cell spreading was observed. Then, adsorption of cell-adhesion proteins, fibronectin (FN), and vitronectin (VN), out of FCS onto SA copolymer surfaces were evaluated using enzyme immunoassay. Both FN and VN adsorption on SA copolymer surfaces were increased with increasing polyamine content in the copolymer, suggesting a crucial role of these cell-adhesion proteins in BAEC adhesion and subsequent growth behavior on SA copolymer surfaces.

Adsorption↗