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H Yanase

Publications and source records attributed to H Yanase.

At least 37 records · Page 2Linked to original sources
PubMed1999

Salivary secretion of highly concentrated chromogranin a in response to noradrenaline and acetylcholine in isolated and perfused rat submandibular glands.

Chromogranin A (CgA) is a member of a family of highly acidic proteins, chromogranins, which are co-stored in the adrenergic neurons and paraneurons and co-released with adrenaline and noradrenaline (NAd) in response to adequate stimulation. The present study provides novel evidence that CgA-like immunoreactivity (IR) is stored in the exocrine cells in the granular convoluted tubule, and is secreted into saliva by stimulation with NAd and acetylcholine (ACh) in the isolated and perfused rat submandibular gland. NAd at 1 microM produced maximum secretion of CgA-like IR (<< 0.9 mM) and a marked increase in salivary flow. Further increases in NAd concentration (10 or 100 microM) yielded concentration-dependent decreases in both responses. ACh at 1 microM produced maximum salivary flow and a slight elevation of CgA-like IR secretion (6 microM); 100 microM ACh decreased the salivary flow but increased the CgA-like IR secretion (0.6 mM). Electron microscopic examination showed vigorous compound exocytosis of secretory granules in the cells of the granular convoluted tubule when the submandibular gland was stimulated with 1 microM NAd. These results provide an experimental basis for the view that the salivary CgA-like IR secretion may be a sensitive and quantitative index of the activity of the sympathetic nervous system innervating the gland.

Acetylcholine↗
PubMed1998

Correlation between potentiation of AP1 DNA binding and expression of c-Fos in association with phosphorylation of CREB at serine133 in thalamus of gerbils with ischemia.

Protein biosynthesis is mainly under the control at the level of gene transcription in eukaryotes. Transcription factors are nuclear proteins with abilities to modulate the activity of RNA polymerase II which is responsible for the formation of messenger RNA from double stranded DNA in the cell nuclei. Binding of a radiolabeled oligonucleotide probe for the transcription factor activator protein-1 (AP1) was transiently potentiated 1 to 6 h after the recirculation of blood supply in the thalamus and striatum, but not in the entorhinal cortex, olfactory bulb, frontal cortex, cerebellar cortex and medulla-pons, in gerbils with transient global forebrain ischemia for 5 min, in addition to the hippocampal subregions. The ischemic insult not only increased the immunoreactivity with an antibody against cyclic AMP response element binding protein (CREB) phosphorylated at serine133, but also induced the expression of both c-Jun and c-Fos family proteins 3 h after the recirculation in the thalamus. Limited proteolysis by Staphylococcus aureus (S. aureus) V8 protease revealed the expression of different partner proteins of AP1 in response to ischemic signals in the thalamus. Moreover, ischemia for 2 min led to more prolonged elevation of AP1 binding in the thalamus at least up to 12 h after the reperfusion than that seen with ischemia for 5 min. These results suggest that potentiation of AP1 DNA binding may at least in part involve mechanisms associated with the expression of c-Fos protein through phosphorylation of CREB at serine133 in the thalamus of gerbils with ischemia.

Amino Acid Sequence↗
PubMed1998

Prolongation by bifemelane of potentiation of AP1 DNA binding in hippocampal CA1 subfield of gerbils with transient forebrain ischemia.

In eukaryotes, protein de novo synthesis is mainly under the control of transcription factors at the level of gene transcription in cell nuclei. Gel retardation electrophoresis was employed for determination of DNA-binding activity of the transcription factor activator protein-1 (AP1), which is a dimer between c-Fos and c-Jun protein families. Binding of a radiolabeled double-stranded oligonucleotide probe for AP1 was rapidly potentiated in the CA1 and CA3 subfields and the dentate gyrus of the hippocampus of gerbils with forebrain ischemia for 5 min. Similarly marked potentiation was seen in the thalamus and the striatum, but not in the frontal cortex, following the recirculation of blood supply. The potentiation was transient in the vulnerable CA1 subfield, but was rather persistent in the thalamus and the striatum in addition to the resistant CA3 subfield and dentate gyrus. However, administration of the neuroprotective drug bifemelane (10 to 20 mg/kg, i.p.) resulted in prolongation of the potentiation of AP1 binding in the CA1 subfield up to 6 hr after ischemia, without significantly affecting that in other central structures. Limited proteolysis revealed that bifemelane induced expression of the AP1 consisting of constructive proteins different from those expressed in control animals in the CA1 subfield. These results suggest that bifemelane may protect neuronal cells against ischemic injuries through molecular mechanisms associated with prolongation of the potentiation of AP1 binding in the vulnerable CA1 subfield after ischemia.

Animals↗
PubMed1998

Mild hypothermia--a revived countermeasure against ischemic neuronal damages.

Although hypothermia as a means of cerebral protection against and resuscitation from ischemic damage has a history of approximately six decades, extensive studies, both in basic and clinical fields, on the mechanisms, effects and methods of mild hypothermia at temperatures no less than 31 degrees C have started only in the last decade. In experiments on rodents, hypothermia in the postischemic period that is introduced up to several hours after reperfusion and is maintained for one day followed by a slow rewarming, significantly protects hippocampal neurons against damage. The mode of action of hypothermia is apparently non-specific and multi-focal in widely progressing cascade reactions in ischemic cells; namely, suppressing: (1) glutamate surge followed by; (2) intraneuronal calcium mobilization; (3) sustained activation of glutamate receptors; (4) dysfunction of blood brain barrier; (5) proliferation of microglial cells; and (6) production of superoxide anions and nitric oxide. In addition, mild hypothermia modulates processes in ischemic condition at the level of cell nucleus, such as the binding of transcription factor AP-1 to DNA, and ameliorates the depression of protein synthesis. This non-specific and widely affecting manner might explain why hypothermia is superior to any medicine developed. Recent clinical trials of mild hypothermia in various individual institutions have revealed significantly beneficial outcomes in some cases, along with an accumulation of practical knowledge of techniques and treatments. Large scale randomized studies involving multiple institutions as well as exchange of informations and ideas are needed for further development of hypothermia treatment.

Animals↗
PubMed1998

Possible involvement of activator protein-1 DNA binding in mechanisms underlying ischemic tolerance in the CA1 subfield of gerbil hippocampus.

Transcription factors are nuclear proteins with an ability to recognize particular nucleotide sequences on double stranded genomic DNAs and thereby modulate the activity of RNA polymerase II which is responsible for the formation of messenger RNAs in cell nuclei. Gel retardation electrophoresis revealed that transient forebrain ischemia for 5 min led to drastic potentiation of binding of a radiolabelled double-stranded oligonucleotide probe for the transcription factor activator protein-1, in the thalamus as well as the CA1 and CA3 subfields and the dentate gyrus of the hippocampus of the gerbils previously given ischemia for 2 min two days before, which is known to induce tolerance to subsequent severe ischemia in the CA1 subfield. By contrast, ischemia for 5 min resulted in prolonged potentiation of activator protein-1 binding in the vulnerable CA1 subfield of the gerbils with prior ischemia for 5 min 14 days before, which is shown to induce delayed death of the pyramidal neurons exclusively in this subfield. Similar prolongation was seen with activator protein-1 binding in the vulnerable thalamus but not in the resistant CA3 subfield and dentate gyrus of the gerbils with such repeated ischemia for 5 min. Limited proteolysis by Staphylococcus aureus V8 protease as well as supershift assays using antibodies against c-Fos and c-Jun proteins demonstrated the possible difference in constructive partner proteins of activator protein-1 among nuclear extracts of the CA1 subfield obtained from gerbils with single, tolerated and repeated ischemia. These results suggest that de novo protein synthesis may underlie molecular mechanisms associated with acquisition of the ischemic tolerance through modulation at the level of gene transcription by activator protein-1 composed of different constructive partner proteins in the CA1 subfield. Possible participation of glial cells in the modulation is also suggested in particular situations.

Animals↗
PubMed1998

Postischemic enhancements of N-methyl-D-aspartic acid (NMDA) and non-NMDA receptor-mediated responses in hippocampal CA1 pyramidal neurons.

Glutamate receptor-mediated responses were investigated by using a whole-cell recording and an intracellular calcium ion ([Ca2+]i) imaging in gerbil postischemic hippocampal slices prepared at 1, 3, 6, 9, 12, and 24 hours after 5-minute ischemia. Bath application of N-methyl-D-aspartic acid (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and kainate showed that NMDA-, AMPA- and kainate-induced currents were enhanced in postischemic CA1 pyramidal neurons at 1 to 12 hours after 5-minute ischemia. NMDA and non-NMDA receptor-mediated excitatory postsynaptic currents (EPSC) were examined in postischemic CA1 pyramidal neurons at 3 hours after 5-minute ischemia to confirm whether synaptic responses are enhanced in the postischemic CA1 pyramidal neurons. The amplitudes of NMDA- and non-NMDA-receptor-mediated EPSC were enhanced in the postischemic CA1 pyramidal neurons. NMDA-, AMPA-, and kainate-induced [Ca2+]i elevations were also examined to determine whether the enhancement of currents is accompanied by the enhancement of [Ca2+]i elevation. The enhancements of NMDA-, AMPA-, and kainate-induced [Ca2+]i elevations were shown in the postischemic CA1. These results indicate that NMDA and non-NMDA receptor-mediated responses are persistently enhanced in the CA1 pyramidal neurons 1 to 12 hours after transient ischemia, and suggest that the enhancement of glutamate receptor-mediated responses may act as one of crucial factors in the pathologic mechanism responsible for leading postischemic CA1 pyramidal neurons to irreversible neuronal injury.

Animals↗
PubMed1998

Escherichia coli transformant expressing the glucose dehydrogenase gene from Bacillus megaterium as a cofactor regenerator in a chiral alcohol production system.

Escherichia coli JM109 (pGDA2) overexpressing the glucose dehydrogenase (GDH) gene from Bacillus megaterium IWG3 was examined for use as a cofactor regenerator. In the asymmetric reduction of ethyl 4-chloro-3-oxobutanoate by E. coli JM109 (pKAR) which is an aldehyde reductase-overproducing transformant, E. coli JM109 (pGDA2) can act as an NADPH regenerator with NADP+ and glucose, similarly to commercially available GDH.

Alcohols↗
PubMed1998

Expression of the extracellular levansucrase and invertase genes from Zymomonas mobilis in Escherichia coli cells.

We investigated the expression and localization in Escherichia coli of sucZE2 and sucZE3, encoding Zymomonas mobilis extracellular levansucrase and invertase, respectively, and lacking a typical N-terminal secretion signal. Levansucrase and invertase were expressed efficiently under the lac and tac promoters in E. coli cells, and some of the levansucrase produced was localized in the periplasmic space. The sucZE2 expression was not lethal to E. coli in the presence of 5% sucrose, and led to the accumulation of levan from sucrose.

Amino Acid Sequence↗
PubMed1998

Increased cellulose production from sucrose with reduced levan accumulation by an Acetobacter strain harboring a recombinant plasmid.

Cellulose production from sucrose by Acetobacter strains is accompanied by the accumulation of a water-soluble polysaccharide, called levan. To improve cellulose productivity, a levansucrase-deficient mutant, LD-2, was derived from Acetobacter strain 757 and used as a host for the construction of recombinant strains. An LD-2 mutant harboring a plasmid containing the sucrase gene, sucZE3, from Zymomonas mobilis together with zliS, a gene that encodes a secretion-activating factor under the control of the Escherichia coli lac promoter, had sucrase activity and produced much cellulose and little levan in a medium containing sucrose. In addition, a mutant levansucrase gene, mutant sacB, from Bacillus subtilis, which encodes a protein with little levan-forming activity, was generated by site-directed mutagenesis and introduced into the LD-2 mutant. This introduction also resulted in the higher cellulose productivity and little levan.

Acetobacter↗
PubMed1998

Morphological analysis of olfactory receptor cells using whole-mount preparations of the rat nasal mucosa.

The distribution and entire shape of olfactory receptor cells were investigated by means of whole-mount preparations of the nasal mucosa. Whole mucosa isolated from the nasal septum of rats was processed, as "a free-floating section", and examined by the avidin-biotin complex (ABC) method using antisera against protein gene product 9.5 (PGP 9.5) and calbindin. Essentially all receptor cells were immunolabeled with the PGP 9.5 antiserum, but only half of PGP 9.5-immunoreactive cells were calbindin-immunoreactive. In the immunostaining of whole-mount preparations, pretreatment of tissues by freeze-thawing and dipping in ethanol and xylene greatly improved the permeability of antibodies. Overview of the nasal septum showed that the dorsal and ventral portions of the rostral olfactory area extended deeply into the respiratory area, making a "semi-lunar" shape. The boundary between the two areas was clearly demarcated, although several receptor cells were scattered in the respiratory area near the boundary. Observation at higher magnification clearly demonstrated that several axons derived from perikarya gathered to form nerve bundles showing a dendritic pattern. Proximal axons close to perikarya displayed beaded structures with intense immunoreactivity. They were electron-microscopically identified as swollen portions of axons which might be formed in association with the axonal flow. The present study showed that whole-mount preparation of the nasal mucosa for immunohistochemistry is a useful tool to analyze the morphology of olfactory receptor cells and axons.

Animals↗
PubMed1998

Immunohistochemical identification of type B intercalated cells in the rat kidney by a monoclonal antibody.

We recently produced monoclonal antibodies using macrophagic cells derived from cultured rat glomeruli as the antigen. One of the antibodies, named OS-3, was found to detect a cell population scattered in collecting ducts of the rat kidney as well as macrophages in various tissues. The present study deals with the cellular and subcellular localization of immunoreactivities with OS-3 in the kidney and other organs of rats. Double immunostaining using OS-3 and an anti-serum against either calbindin or epidermal cytokeratin showed that OS-3-immunoreactive cells exist exclusively in both the connecting segment and cortical collecting duct, and differ from calbindin- or cytokeratin-positive epithelial cells. Ultrastructurally, OS-3-immunoreactive cells appeared spherical in shape with few cytoplasmic microprojections on the narrow apical surface. Their relatively dark cytoplasm contained numerous mitochondria and a developed tubulo-vesicular system. The intense immunoreactivity was selectively localized in the basolateral membrane exhibiting shallow but complicated infoldings. Distribution and ultrastructural properties of the OS-3-immunoreactive cells showed that they were type B intercalated cells, which are engaged in the regulation of the acid-base balance mainly by secreting HCO3-. Another positive staining with OS-3 was found in the macula densa and some epithelial cells of Bowman's capsule, the former monitoring Cl- concentrations in the urine. Immunoblotting of extracts from the rat kidney demonstrated a protein band immunoreactive to OS-3 at a molecular weight of 43 kDa. Aside from the kidney, a specific and intense immunoreactivity with OS-3 was also found in the epithelial cells of the pancreatic excretory duct and in the secretory cells of the salivary, pyloric and duodenal glands, all of which are HCO3- -secreting cells. These immunohistochemical findings imply that OS-3 is useful for the detection of type B intercalated cells and recognizes a functional molecule involved in the production/secretion of HCO3- or transport of Cl-.

Animals↗
PubMed1997

Cloning of poly(3-hydroxybutyrate) depolymerase from a marine bacterium, Alcaligenes faecalis AE122, and characterization of its gene product.

A DNA fragment that carries the gene coding for poly(3-hydroxybutyrate) (PHB) depolymerase was cloned from the chromosomal DNA of Alcaligenes faecalis AE122 isolated from seawater. The open reading frame encoding the precursor of the PHB depolymerase was 1905 base pairs (bp) long, corresponding to a protein of 635 amino acid residues (M(r) = 65,208). The promoter site, which could be recognized by Escherichia coli RNA polymerase, was upstream from the gene, and the sequence adhering to the ribosome-binding sequence was found in front of the gene. The deduced amino acid sequence agreed with the N-terminal amino acid sequence of the purified PHB depolymerase from amino acid 28 onwards. Analysis of the deduced amino acid sequence revealed the domain structure of the protein; a signal peptide of 27 amino acids long was followed by a catalytic domain of about 400 amino acids, a fibronectin type III module sequence, and a putative substrate binding domain. The molecular mass (62,526) of the mature protein deduced from the nucleotide sequence was significantly lower than the value (95 kDa) estimated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but coincided well with the value (62,426) estimated from matrix-assisted laser desorption ionization mass spectra. By comparison of the primary structure with those of other PHB depolymerases, the substrate binding domain was found to consist of two domains, PHB-specific and poly(3-hydroxyvalerate)-specific ones, connected by a linker region. The PHB depolymerase gene was expressed in Escherichia coli under the control of the tac promoter. The enzyme expressed in E. coli was purified from culture broth and showed the same catalytic properties as the enzyme from A. faecalis.

Alcaligenes↗
PubMed1997

Continuous monitoring and regulating of brain temperature in the conscious and freely moving ischemic gerbil: effect of MK-801 on delayed neuronal death in hippocampal CA1.

Many glutamate antagonists have been reported to have a neuroprotective effect against ischemic brain damage; however, some of them have been also reported to induce hypothermia that confers remarkable neuroprotection against the damage. In order to avoid the confounding effects of hypothermia, we assembled a telemeter-based brain temperature control system that allows continuous monitoring and regulating of brain temperature during an ischemic insult and in the post-ischemic period in conscious and freely moving animals. Experiments were performed in gerbils that were subjected to administration of MK-801 (3, 5, and 10 mg/kg) and/or to 5-min ischemia. The system monitored continuous changes in brain temperature and regulated brain temperature at normothermic levels, revealing that a neuroprotective effect of 3 mg/kg MK-801 against ischemia-induced delayed hippocampal CA1 neuronal death was mainly due to hypothermia, whereas a high dose of MK-801 (5 and 10 mg/kg) produced a neuroprotective effect even when the brain temperature was maintained at normothermic levels. These results indicate that this system is very useful to test potential antiischemic agents, especially when the agents have hypothermic side effects.

Animals↗
PubMed1997

Enzymatic production of ethyl (R)-4-chloro-3-hydroxybutanoate: asymmetric reduction of ethyl 4-chloro-3-oxobutanoate by an Escherichia coli transformant expressing the aldehyde reductase gene from yeast.

The asymmetric reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (R)-4-chloro-3-hydroxybutanoate (CHBE) using Escherichia coli JM109 (pKAR) cells expressing the aldehyde reductase gene from Sporobolomyces salmonicolor AKU4429 as a catalyst was studied. The reduction required NADP+, glucose and glucose dehydrogenase for NADPH regeneration. In an aqueous system, the substrate was unstable, and inhibition of the reaction by the substrate was also observed. Efficient conversion of COBE to (R)-CHBE with a satisfactory enantiomeric excess (ee) was attained on incubation with transformant cells in an n-butyl acetate/water two-phase system containing the above NADPH-regeneration system. Under the optimized conditions, with the periodical addition of COBE, glucose and glucose dehydrogenase, the (R)-CHBE yield reached 1530 mM (255 mg/ml) in the organic phase, with a molar conversion yield of 91.1% and an optical purity of 91% ee. The calculated turnover of NADP+, based on the amounts of NADP+ added and CHBE formed, was about 5100 mol/mol.

Aldehyde Reductase↗
PubMed1997

Lidocaine suppresses the anoxic depolarization and reduces the increase in the intracellular Ca2+ concentration in gerbil hippocampal neurons.

BACKGROUND: The movement of ions, particularly Ca2+, across the plasma membrane of neurons is regarded as an initial element of the development of ischemic neuronal damage. Because the mechanism by which lidocaine protects neurons against ischemia is unclear, the effects of lidocaine on the ischemia-induced membrane depolarization, histologic outcome, and the change in the intracellular Ca2+ concentration in the gerbil hippocampus were studied. METHODS: The changes in the direct-current potential shift in the hippocampal CA1 area produced by transient forebrain ischemia for 4 min were compared in animals given lidocaine (0.8 micromol administered intracerebroventricularly) 10 min before ischemia and those given saline. The histologic outcome was evaluated 7 days after ischemia by assessing delayed neuronal death in hippocampal CA1 pyramidal cells in these animals. In a second study, hypoxia-induced intracellular Ca2+ increases were evaluated by in vitro microfluorometry in gerbil hippocampal slices, and the effects of lidocaine (10, 50, and 100 microM) on the Ca2+ accumulation were examined. In addition, the effect of lidocaine (100 microM) drug perfusion with a Ca2+-free ischemia-like medium was investigated. RESULTS: The preischemic administration of lidocaine delayed the onset of the ischemia-induced membrane depolarization (anoxic depolarization) and reduced its maximal amplitude. The histologic outcome was improved by the preischemic treatment with lidocaine. The in vitro hypoxia-induced increase in the intracellular concentration of Ca2+ was suppressed by the perfusion with lidocaine-containing mediums (50 and 100 microM), regarding the initiation and the extent of the increase. The hypoxia-induced intracellular Ca2+ elevation in the Ca2+-free condition was similar to that in the Ca2+-containing condition. Perfusion with lidocaine (100 microM) inhibited this elevation in the Ca2+-free condition. CONCLUSIONS: Lidocaine helps protect neurons from ischemia by suppressing the direct-current potential shift, by inhibiting the release of Ca2+ from the intracellular Ca2+ stores, and by inhibiting the influx from the extracellular space.

Anesthetics, Local↗
PubMed1996

Crystallization and preliminary X-ray diffraction study of aldehyde reductase from a red yeast, Sporobolomyces salmonicolor.

Crystals of aldehyde reductase from a red yeast, Sporobolomyces salmonicolor, have been grown from an ammonium sulfate solution, pH 7.0, by means of the vapor-diffusion procedure. The crystals belong to the hexagonal system, space group P6(1)22 or its enantiomorph, P6(5)22, with unit-cell dimensions of a = 72.2 and c = 320 A. The X-ray diffraction patterns extend to at least 2 A resolution with the use of synchrotron radiation. The crystals are stable on exposure to X-rays and suitable for high-resolution X-ray structure determination.

Journal Article↗
PubMed1996

Overproduction and characterization of the StsI restriction endonuclease.

The StsI restriction endonuclease (R-StsI), a class-IIS restriction endonuclease, found in Streptococcus sanguis 54, is a heteroschizomer of R-FokI, which recognizes 5'-GGATG-3'. To overproduce R-StsI in Escherichia coli, the coding region of R-StsI was joined to the tac promoter of an expression vector, pKK223-3. By introduction of the plasmid into E. coli UT481 cells expressing the fokIM gene, R-StsI activity was overproduced, from which R-StsI was purified homogeneously. We compared the properties of R-StsI with those of R-FokI. The optimum reaction conditions for R-StsI were quite different fron those for R-FokI. R-StsI is an acidic protein (pI 6.3). Anti-R-StsI serum did not cross-react with R-FokI, indicating three-dimensional structural dissimilarity. The domain structure of R-StsI was elucidated by digestion with trypsin. In the presence of substrate DNA, R-StsI was digested to yield 45-kDa N-terminal and 23-kDa C-terminal fragments. The amino-acid sequences around the trypsin cleavage sites of R-StsI and R-FokI were quite homologous.

Amino Acid Sequence↗