98 research outputs found

    The Electrical Conductivity and Activation Energy for Ionic Conductance of the Fused Salts Mixtures

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    The electrical conductivity of the fused salt systems KCl-LiCl, KCl-NaCl, KCl-KBr and NaCl-NaBr have been determined as functions of both temperature and molar fractions, and the activation energy for ionic conductance is calculated with Frenkel's theory. The isotherms of equivalent conductivity against molar fractions for system KCl-LiCl showed negative deviation from additivity and a minimum value was found at 20 mol % LiCl. The activation energy showed positive deviation from additivity and a maximum value was found at 40 mol % LiCl. In the KCl-NaCl, KCl-KBr and NaCl-NaBr systems, the isotherms of equivalent conductivity showed negative deviation from additivity and the activation energy showed positive deviation. The deviation of the activation energy from additivity are caused by the interactions between different types of cation and cation hole or anion and anion hole in the liquid mixture

    The Viscosity of the Fused Salts Mixtures : KCl-LiCl and KCl-NaCl Systems

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    Isotherms of viscosity against molar compositions have been investigated over extended temperature ranges for the systems KCl-LiCl and KCl-NaCl and the activation energy for viscous flow are calculated with Eyring's theory. The activation energy showed negative deviation from additivity in KCl-LiCl system, but in KCl-NaCl system the activation energy showed positive deviation from additivity in the range of 0〜40 mol % NaCl and showed negative deviation in the range of 40〜100 mol % NaCl. These deviations are caused by the interaction between different types of molecules or ion pairs in the liquid mixture

    CRISPR/Cas9 mediated genome editing in ES cells and its application for chimeric analysis in mice

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    Oji, A., Noda, T., Fujihara, Y. et al. CRISPR/Cas9 mediated genome editing in ES cells and its application for chimeric analysis in mice. Sci Rep 6, 31666 (2016). https://doi.org/10.1038/srep3166

    Crystal structure of a Ca2+-dependent regulator of flagellar motility reveals the open-closed structural transition

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    Sperm chemotaxis toward a chemoattractant is very important for the success of fertilization. Calaxin, a member of the neuronal calcium sensor protein family, directly acts on outer-arm dynein and regulates specific flagellar movement during sperm chemotaxis of ascidian, Ciona intestinalis. Here, we present the crystal structures of calaxin both in the open and closed states upon Ca2+ and Mg2+ binding. The crystal structures revealed that three of the four EF-hands of a calaxin molecule bound Ca2+ ions and that EF2 and EF3 played a critical role in the conformational transition between the open and closed states. The rotation of α7 and α8 helices induces a significant conformational change of a part of the α10 helix into the loop. The structural differences between the Ca2+- and Mg2+-bound forms indicates that EF3 in the closed state has a lower affinity for Mg2+, suggesting that calaxin tends to adopt the open state in Mg2+-bound form. SAXS data supports that Ca2+-binding causes the structural transition toward the closed state. The changes in the structural transition of the C-terminal domain may be required to bind outer-arm dynein. These results provide a novel mechanism for recognizing a target protein using a calcium sensor protein

    Identification of multiple male reproductive tractspecific proteins that regulate sperm migration through the oviduct in mice

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    Fujihara, Y., Noda, T., Kobayashi, K., Oji, A., Kobayashi, S., Matsumura, T., . . . Ikawa, M. (2019). Identification of multiple male reproductive tractspecific proteins that regulate sperm migration through the oviduct in mice. Proceedings of the National Academy of Sciences of the United States of America, 116(37), 18498-18506. doi:10.1073/pnas.190873611

    Concomitant administration of radiation with eribulin improves the survival of mice harboring intracerebral glioblastoma

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    Glioblastoma is the most common and devastating type of malignant brain tumor. We recently found that eribulin suppresses glioma growth in vitro and in vivo and that eribulin is efficiently transferred into mouse brain tumors at a high concentration. Eribulin is a non‐taxane microtubule inhibitor approved for breast cancer and liposarcoma. Cells arrested in M‐phase by chemotherapeutic agents such as microtubule inhibitors are highly sensitive to radiation‐induced DNA damage. Several recent case reports have demonstrated the clinical benefits of eribulin combined with radiation therapy for metastatic brain tumors. In this study, we investigated the efficacy of a combined eribulin and radiation treatment on human glioblastoma cells. The glioblastoma cell lines U87MG, U251MG and U118MG, and SJ28 cells, a patient‐derived sphere culture cell line, were used to determine the radiosensitizing effect of eribulin using western blotting, flow cytometry and clonogenic assay. Subcutaneous and intracerebral glioma xenografts were generated in mice to assess the efficacy of the combined treatment. The combination of eribulin and radiation enhanced DNA damage in vitro. The clonogenic assay of U87MG demonstrated the radiosensitizing effect of eribulin. The concomitant eribulin and radiation treatment significantly prolonged the survival of mice harboring intracerebral glioma xenografts compared with eribulin or radiation alone (P < .0001). In addition, maintenance administration of eribulin after the concomitant treatment further controlled brain tumor growth. Aberrant microvasculature was decreased in these tumors. Concomitant treatment with eribulin and radiation followed by maintenance administration of eribulin may serve as a novel therapeutic strategy for glioblastomas

    Large-Scale Gene Disruption in Magnaporthe oryzae Identifies MC69, a Secreted Protein Required for Infection by Monocot and Dicot Fungal Pathogens

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    To search for virulence effector genes of the rice blast fungus, Magnaporthe oryzae, we carried out a large-scale targeted disruption of genes for 78 putative secreted proteins that are expressed during the early stages of infection of M. oryzae. Disruption of the majority of genes did not affect growth, conidiation, or pathogenicity of M. oryzae. One exception was the gene MC69. The mc69 mutant showed a severe reduction in blast symptoms on rice and barley, indicating the importance of MC69 for pathogenicity of M. oryzae. The mc69 mutant did not exhibit changes in saprophytic growth and conidiation. Microscopic analysis of infection behavior in the mc69 mutant revealed that MC69 is dispensable for appressorium formation. However, mc69 mutant failed to develop invasive hyphae after appressorium formation in rice leaf sheath, indicating a critical role of MC69 in interaction with host plants. MC69 encodes a hypothetical 54 amino acids protein with a signal peptide. Live-cell imaging suggested that fluorescently labeled MC69 was not translocated into rice cytoplasm. Site-directed mutagenesis of two conserved cysteine residues (Cys36 and Cys46) in the mature MC69 impaired function of MC69 without affecting its secretion, suggesting the importance of the disulfide bond in MC69 pathogenicity function. Furthermore, deletion of the MC69 orthologous gene reduced pathogenicity of the cucumber anthracnose fungus Colletotrichum orbiculare on both cucumber and Nicotiana benthamiana leaves. We conclude that MC69 is a secreted pathogenicity protein commonly required for infection of two different plant pathogenic fungi, M. oryzae and C. orbiculare pathogenic on monocot and dicot plants, respectively

    〈Originals〉Trib1 and Trib2 inhibit granulocytic differentiation by suppressing Akt pathway

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    [Abstract] Background :Overexpression of Tribbles homolog 1 (Tribl) and Tribbles homolog 2 (Trib2) in hematopoietic stem/progenitor cells evokes acute myeloid leukemia (AML) in murine transplantation models. Degradation of CCAAT-enhancer-binding-protein α (C/EBPα) plays a crucial role in Trib1 or Trib2-induced AML. However, because C/EBPα knockout mice do not develop AML, it is likely that Trib1 and Trib2 influence other signaling pathways besides C/EBPα. Elevated Akt phosphorylation is considered to contribute to the development of AML. In contrast, two groups recently reported that reduced Akt activity is involved in the pathogenesis of leukemia. We performed this study to reveal the role of Akt signaling in Trib family-induced AML.Methods : G-CSF-induced granulocytic differentiation of 32D cells was assessed morphologically and phenotypically. G-CSF-induced signaling wasassessed by Westernblotting. Results : Overexpression of Trib1 or Trib2 inhibited GCSF-induced granulocytic differentiation of 32D cells, which was accompanied by reduced Akt phosphorylation. Also, an Akt inhibitor API-2 blocked G-CSF-induced granulocytic differentiation independently of C/EBPα degradation. Furthermore, retroviral C/EBPα restoration did not completely abolish the differentiation block caused by Trib1 and Trib2. Conclusion :Trib1 and Trib2 block granulocytic differentiation, at least partially, by suppressing Akt phosphorylation

    Ghrelin Treatment of Cachectic Patients with Chronic Obstructive Pulmonary Disease: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

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    BACKGROUND: Pulmonary cachexia is common in advanced chronic obstructive pulmonary disease (COPD), culminating in exercise intolerance and a poor prognosis. Ghrelin is a novel growth hormone (GH)-releasing peptide with GH-independent effects. The efficacy and safety of adding ghrelin to pulmonary rehabilitation (PR) in cachectic COPD patients were investigated. METHODOLOGY/PRINCIPAL FINDINGS: In a multicenter, randomized, double-blind, placebo-controlled trial, 33 cachectic COPD patients were randomly assigned PR with intravenous ghrelin (2 µg/kg) or placebo twice daily for 3 weeks in hospital. The primary outcomes were changes in 6-min walk distance (6-MWD) and the St. George Respiratory Questionnaire (SGRQ) score. Secondary outcomes included changes in the Medical Research Council (MRC) scale, and respiratory muscle strength. At pre-treatment, serum GH levels were increased from baseline levels by a single dose of ghrelin (mean change, +46.5 ng/ml; between-group p<0.0001), the effect of which continued during the 3-week treatment. In the ghrelin group, the mean change from pre-treatment in 6-MWD was improved at Week 3 (+40 m, within-group p = 0.033) and was maintained at Week 7 (+47 m, within-group p = 0.017), although the difference between ghrelin and placebo was not significant. At Week 7, the mean changes in SGRQ symptoms (between-group p = 0.026), in MRC (between-group p = 0.030), and in maximal expiratory pressure (MEP; between-group p = 0.015) were better in the ghrelin group than in the placebo group. Additionally, repeated-measures analysis of variance (ANOVA) indicated significant time course effects of ghrelin versus placebo in SGRQ symptoms (p = 0.049) and MEP (p = 0.021). Ghrelin treatment was well tolerated. CONCLUSIONS/SIGNIFICANCE: In cachectic COPD patients, with the safety profile, ghrelin administration provided improvements in symptoms and respiratory strength, despite the lack of a significant between-group difference in 6-MWD. TRIAL REGISTRATION: UMIN Clinical Trial Registry C000000061

    Larval pufferfish protected by maternal tetrodotoxin

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    Marine pufferfish contain tetrodotoxin (TTX), an extremely potent neurotoxin. All species of the genus Takifugu accumulate TTX in the liver and ovaries, although the tissue(s) in which it is localized can differ among species. TTX is the major defense strategy the pufferfish appears to use against predators. TTX is also used as a male-attracting pheromone during spawning. Here we demonstrate an additional (and unexpected) use of maternal TTX in the early larval stages of the Takifugu pufferfish. Predation experiments demonstrated that juveniles of all the species of fish used as predators ingested pufferfish larvae, but spat them out promptly. Liquid Chromatography-Tandem Mass Spectrometry (LC-MSMS) analysis revealed that the pufferfish larvae contain a small quantity of TTX, which is not enough to be lethal to the predators. Immunohistochemical analysis with anti-TTX monoclonal antibody revealed that the TTX is primarily localized in the body surface of the larvae as a layer of protection. Our study showed the female parent of the Takifugu pufferfish vertically transfers TTX to the larvae through its accumulation in the ovaries, and subsequent localization on the body surface of the larvae
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