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Susumu Ishii - One of the best experts on this subject based on the ideXlab platform.
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Cloning of complimentary deoxyribonucleic acid encoding follicle-stimulating hormone and luteinizing hormone β subunit Precursor Molecules in Reeves’s turtle (Geoclemys reevesii) and Japanese grass lizard (Takydromus tachydromoides)
General and comparative endocrinology, 2003Co-Authors: Youichi Aizawa, Susumu IshiiAbstract:Abstract Reptilia is the only vertebrate class in which cDNA for the gonadotropin β subunit Precursor Molecule has not been cloned. We have isolated the full-length cDNA clone encoding the LH β subunit Precursor Molecule and a partial cDNA clone encoding the FSH β subunit Precursor Molecule from a pituitary cDNA library of Reeves’s turtle. We further clarified the nucleotide sequence of the remaining part of the turtle FSH β cDNA and that of full-length cDNA encoding the LH β subunit Precursor Molecule of the Japanese grass lizard, by means of the 5 ′ rapid amplification of cDNA end (RACE) and 3 ′ RACE. The nucleotide sequence of the turtle FSH β cDNA we determined was 584 bp long and contained the coding sequence, 5 ′ untranslated region (UTR) and 3 ′ UTR of 396, 34, and 154 bp, respectively. The nucleotide sequence of the turtle LH β we isolated was 498 bp long and contained the coding sequence, 5 ′ UTR and 3 ′ UTR of 420, 7, and 71 bp, respectively. The nucleotide sequence of the lizard LH β we determined was 537 bp long and contained the coding sequence, 5 ′ UTR and 3 ′ UTR of 441, 35, and 61 bp, respectively. Amino acid sequences deduced from coding regions of the turtle FSH β, LH β and the lizard LH β were 131, 139, and 146 residues, respectively. Referring to the amino acid sequences of the bullfrog FSH and LH β subunit Molecules determined chemically, we deduced the amino acid sequences of mature peptide. Amino acid sequences of mature peptides of the turtle FSH, turtle LH, and the lizard LH were 111, 112, and 112 residues, respectively. Amino acid sequences of the mature peptides were compared with those of other vertebrates. The amino acid sequence of the turtle FSH β subunit Molecule was 84.7–85.6, 67.8–71.4, and 61.3–62.2% identical to the FSH sequence of birds, mammals, and amphibians, respectively. The amino acid sequence of the turtle LH β subunit Molecule was 51.6–54.6, 36.2–48.7, and 56.3–57.5% identical to the LH sequence of birds, mammals, and amphibians, respectively. The amino acid sequence of the lizard LH β subunit Molecule was 39.1–47.1, 32.9–43.0, and 46.0–47.3% identical to the LH sequence of birds, mammals, and amphibians, respectively. These identity values suggest that the turtle or reptilian FSH β subunit Molecule is more closely related to avian and mammalian FSH β subunit Molecules than to amphibian FSH β subunit Molecules but reptilian LH β subunit Molecules are more closely related to amphibian LH β subunit Molecules than to avian and mammalian LH β subunit Molecules. This discrepancy in the molecular similarity relationship found in the reptilian FSH and LH β subunit Molecules can be interpreted by assuming that evolution speed was not the same among hormone species and also among vertebrate groups.
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Cloning of cDNA Encoding the Common Alpha Subunit Precursor Molecule of Pituitary Glycoprotein Hormones in the Australian Lungfish,Neoceratodus forsteri
General and comparative endocrinology, 1998Co-Authors: Yuta Arai, Kaoru Kubokawa, Susumu Ishii, Jean M.p. JossAbstract:Abstract We have isolated cDNA clones encoding a putative glycoprotein hormone alpha subunit Precursor Molecule from a pituitary cDNA library of the Australian lungfish ( Neoceratodus forsteri ) by a two-step plaque hybridization technique initially using cDNA encoding the toad glycoprotein hormone alpha subunit Precursor Molecule as the hybridization probe. The inserts (799 bp) of two of the isolated cDNA clones contained sequences of 5′ and 3′ untranslated regions, including a poly(A) stretch, and the entire coding sequence of the alpha subunit Precursor Molecule. The deduced amino acid sequence showed that its signal peptide consists of 24 residues and its mature protein 97 residues. In the mature protein, there is an insert of one residue (Ala) just after the 9th residue. This insert is unique to the Australian lungfish among vertebrate species studied. The amino acid sequence of the mature protein shares the common, or the same-group, amino acid residues at 9 positions with tetrapod and not actinopterygian vertebrates, while only one residue is common to some teleosts and the lungfish to the exclusion of the tetrapods. The overall sequence of the mature protein of the Australian lungfish also shares more similarity with those of tetrapods (69 to 84%) than it does with teleosts (57 to 74%). These results on the relation of the alpha subunit Precursor Molecule between the lungfish and other vertebrates are consistent with the recent molecular phylogenetic studies suggesting a closer relationship between lungfish and tetrapods than between lungfish and teleosts. We also found that the primary structure of the lungfish alpha subunit is slightly but significantly more similar to that of homeothermic vertebrates than to that of amphibians. This may be due to specialization of the amphibian alpha subunit Molecules.
Jane C. Kaltenbach - One of the best experts on this subject based on the ideXlab platform.
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Localization of xenopsin and xenopsin Precursor fragment immunoreactivities in the skin and gastrointestinal tract of Xenopus laevis
Cell and Tissue Research, 1992Co-Authors: Kirsten C. Sadler, Charles L. Bevins, Jane C. KaltenbachAbstract:Xenopsin (Xp) and xenopsin Precursor fragment (XPF) are bioactive peptides derived from a single Precursor Molecule; both were isolated previously from extracts of Xenopus laevis skin. The present immunohistochemical study was undertaken to determine the specific cellular localization of these two peptides in the skin and also in the gastrointestinal tract of adult Xenopus . We report here that Xp-like and XPF-like immuno-reactivities co-exist in the granular glands of the skin and specific granular cells in the lower esophagus and stomach. However, only Xp-like immunoreactivity, not XPF-like immunoreactivity, was detected in tall, thin cells of the duodenum and in club-shaped cells of the large intestine. The immunochemical co-localization of the two peptides in specific cells of the skin, lower esophagus and stomach suggests that the same gene is expressed in each of these cells, and that the Precursor Molecule undergoes similar post-translational processing. In contrast, the observation that certain cells of the duodenum and large intestine display only one peptide immunoreactivity suggests an alternative phenomenon, possibly involving selective peptide accumulation or expression of a different gene.
Robert Kołos - One of the best experts on this subject based on the ideXlab platform.
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Formation and Spectroscopy of Dicyanotriacetylene (NC8N) in Solid Kr
2015Co-Authors: Michał Turowski, Stéphane Douin, Claudine Crépin, Robert KołosAbstract:Thermally induced creation of dicyanotriacetylene (NC8N) was observed in solid krypton. Samples were obtained by cryogenic trapping of gaseous cyanoacetylene/Kr mixtures subjected to electric discharges. Strong a 3Σ+u → X 1Σ+g phosphorescence of NC8N is reported here for the first time; its vibronic structure permitted the measurement of several ground-state vibrational frequencies. Other chemical species, mostly smaller than the Precursor Molecule, have also been formed, among them the dicarbon Molecule (C2), and these may serve as indispensable building blocks in the NC8N synthesis. Processes leading to the elongation of cyanoacetylenic chains are of potential importance for the chemistry of icy grains present in the interstellar gas clouds
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Formation and Spectroscopy of Dicyanotriacetylene (NC8N) in Solid Kr
The journal of physical chemistry. A, 2014Co-Authors: Michał Turowski, Claudine Crépin, Stéphane Douin, Robert KołosAbstract:Thermally induced creation of dicyanotriacetylene (NC8N) was observed in solid krypton. Samples were obtained by cryogenic trapping of gaseous cyanoacetylene/Kr mixtures subjected to electric discharges. Strong a 3Σ+u → X 1Σ+g phosphorescence of NC8N is reported here for the first time; its vibronic structure permitted the measurement of several ground-state vibrational frequencies. Other chemical species, mostly smaller than the Precursor Molecule, have also been formed, among them the dicarbon Molecule (C2), and these may serve as indispensable building blocks in the NC8N synthesis. Processes leading to the elongation of cyanoacetylenic chains are of potential importance for the chemistry of icy grains present in the interstellar gas clouds.
Anthony Pandolfo - One of the best experts on this subject based on the ideXlab platform.
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high surface area templated lifepo4 from a single source Precursor Molecule
Energy and Environmental Science, 2011Co-Authors: Matthew R Hill, Gregory J Wilson, Laure Bourgeois, Anthony PandolfoAbstract:The preparation of a stoichiometric dispersion of nanostructured LiFePO4 clusters with intimate contact to carbon is described. This material exhibits outstanding performance for hybrid energy storage applications. A synthetic process, involving a novel single molecular source Precursor, was developed and used to infiltrate a structured mesoporous carbon template. Subsequent optimisation of the infiltration process, reductive pyrolysis and secondary dispersion of the active materials for electrode coatings gave highly effective LiFePO4/C composite electrodes suitable for high power applications. The materials were found to have surface areas in excess of 800 m2 g−1 and TEM revealed an intimate contact to the carbon matrix as a result of the single source Precursor employed. Extensive electrochemical performance evaluation, at rates exceeding 20 C, confirmed a resilient stable material capable of delivering exceptional high rate performance which is attributed to the periodic, interconnected mesopores (5–6 nm) and also the intimate LiFePO4/C content delivered from the single source Precursor. Galvanostatic charge–discharge cycling demonstrated the materials' excellent stability and high utilization, with a specific discharge capacity of 163 A h kg−1 (close to theoretical unity of 170 A h kg−1) at 0.2 C and 128 A h kg−1 at 23 C, an exceptional result relative to lower surface area analogues. Power delivery was almost three times that of commercial LiFePO4 at 10 C. These materials are well suited for application in high power energy storage devices including high power lithium batteries and hybrid devices.
Roser Valentí - One of the best experts on this subject based on the ideXlab platform.
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Spontaneous dissociation of Co2(CO)8 and autocatalytic growth of Co on SiO2: A combined experimental and theoretical investigation
Beilstein journal of nanotechnology, 2012Co-Authors: Kaliappan Muthukumar, Harald O. Jeschke, Roser Valentí, E. Begun, Johannes Schwenk, Fabrizio Porrati, Michael HuthAbstract:We present experimental results and theoretical simulations of the adsorption behavior of the metal–organic Precursor Co2(CO)8 on SiO2 surfaces after application of two different pretreatment steps, namely by air plasma cleaning or a focused electron beam pre-irradiation. We observe a spontaneous dissociation of the Precursor Molecules as well as autodeposition of cobalt on the pretreated SiO2 surfaces. We also find that the differences in metal content and relative stability of these deposits depend on the pretreatment conditions of the substrate. Transport measurements of these deposits are also presented. We are led to assume that the degree of passivation of the SiO2 surface by hydroxyl groups is an important controlling factor in the dissociation process. Our calculations of various slab settings, using dispersion-corrected density functional theory, support this assumption. We observe physisorption of the Precursor Molecule on a fully hydroxylated SiO2 surface (untreated surface) and chemisorption on a partially hydroxylated SiO2 surface (pretreated surface) with a spontaneous dissociation of the Precursor Molecule. In view of these calculations, we discuss the origin of this dissociation and the subsequent autocatalysis.
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Interaction of W(CO)6 with SiO2 Surfaces - A Density Functional Study
Physical Review B, 2011Co-Authors: Kaliappan Muthukumar, Ingo Opahle, Juan Shen, Harald O. Jeschke, Roser ValentíAbstract:The interaction of tungsten hexacarbonyl [W(CO)6] Precursor Molecules with SiO2 substrates is investigated by means of density functional theory calculations with and without inclusion of long-range van der Waals interactions. We consider two different surface models, a fully hydroxylated and a partially hydroxylated SiO2 surface, corresponding to substrates under different experimental conditions. For the fully hydroxylated surface, we observe only a weak interaction between the Precursor Molecule and the substrate, with physisorption of W(CO)6. Inclusion of van der Waals corrections results in a stabilization of the Molecules on this surface, but does not lead to significant changes in the chemical bonding. In contrast, we find a spontaneous dissociation of the Precursor Molecule on the partially hydroxylated SiO2 surface, where chemisorption of a W(CO)5 fragment is observed upon removal of one of the CO ligands from the Precursor Molecule. Irrespective of the hydroxylation, the Precursor Molecule prefers binding of more than one of its CO ligands. In light of these results, implications for the initial growth stage of tungsten nanodeposits on SiO2 in an electron-beam-induced deposition process are discussed.