885 research outputs found

    Calcareous Nannoplankton Thanatocoenoses in Surface Sediments from Seas Around Japan

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    Calcareous nannoplankton thanatocoenoses have been investigated in 437 surface sediments collected from seas around the Japanese Islands and 34 species are identified. The geographical distributions of coccolith species are delineated separately from coastal (Gephyrocapsa oceanica, Helicosphaera carteri s.l. and Braarudosphaera bigelowii) to oceanic water forms (Florisphaera profunda, Calcidiscus leptoporus, and Rhabdosphaera clavigera) and from cold (Coccolithus pelagicus) to warm water forms (F. profunda, R. clavigera, Umbilicosphaera sibogae and Calciosolenia spp.), as determined by oceanic conditions. The Q-mode cluster analysis of the coccolith floras yields ten biotopes based on the distribution pattern of characteristic species. These biotopes can be explained by the combination of salinity and temperature. Transfer functions formulated through multiple regression analysis relating the assemblages to such parameters as mean annual surface temperatures and salinities also give accurate estimates for water temperature and salinity, with standard errors of 1.30ā„ƒ and 0.14ā€°, respectively. Temperature and salinity, therefore, are important parameters in controlling the distribution of coccolith floras in this area. Transfer functions have been applied to coccolith floras, which have existed for the last 22, 000 years and preserved in sediments penetrated by three piston cores in the present-day domain of the Kuroshio Current and of the Kuroshio front. The warm and cool events contemporary to the well known series of episodes in the Atlantic Ocean, and the phase called the Yayoi regression at about 2, 000 years B.P. are recognized

    Iron Emission Lines on the Galactic Ridge Observed with Suzaku

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    In order to elucidate origin of the Galactic Ridge X-ray Emission, we analyzed Suzaku data taken at various regions along the Galactic plane and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at ~6.4 keV,~6.7 keV and ~6.97 keV, which are K-lines from neutral (or low-ionized), He-like, and H-like iron ions, respectively. The 6.7 keV line is clearly seen in all the observed regions and its longitudinal distribution is consistent with that determined from previous observations. The 6.4 keV emission line was also found in various Galactic plane regions (b~0). Differences in flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines between the Galactic plane and the Galactic center regions are studied and its implication is discussed.Comment: Accepted for publication in PASJ Suzaku 3rd special issu

    Transcriptome-Wide Identification of Preferentially Expressed Genes in the Hypothalamus and Pituitary Gland

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    To identify preferentially expressed genes in the central endocrine organs of the hypothalamus and pituitary gland, we generated transcriptome-wide mRNA profiles of the hypothalamus, pituitary gland, and parietal cortex in male mice (12ā€“15ā€‰weeks old) using serial analysis of gene expression (SAGE). Total counts of SAGE tags for the hypothalamus, pituitary gland, and parietal cortex were 165824, 126688, and 161045 tags, respectively. This represented 59244, 45151, and 55131 distinct tags, respectively. Comparison of these mRNA profiles revealed that 22 mRNA species, including three potential novel transcripts, were preferentially expressed in the hypothalamus. In addition to well-known hypothalamic transcripts, such as hypocretin, several genes involved in hormone function, intracellular transduction, metabolism, protein transport, steroidogenesis, extracellular matrix, and brain disease were identified as preferentially expressed hypothalamic transcripts. In the pituitary gland, 106 mRNA species, including 60 potential novel transcripts, were preferentially expressed. In addition to well-known pituitary genes, such as growth hormone and thyroid stimulating hormone beta, a number of genes classified to function in transport, amino acid metabolism, intracellular transduction, cell adhesion, disulfide bond formation, stress response, transcription, protein synthesis, and turnover, cell differentiation, the cell cycle, and in the cytoskeleton and extracellular matrix were also preferentially expressed. In conclusion, the current study identified not only well-known hypothalamic and pituitary transcripts but also a number of new candidates likely to be involved in endocrine homeostatic systems regulated by the hypothalamus and pituitary gland

    Enhancement of intracellular Ī³-tocopherol levels in cytokine-stimulated C3H 10T1/2 fibroblasts: relation to NO synthesis, isoprostane formation, and tocopherol oxidation

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    Stimulation of C3H 10T1/2 murine fibroblasts with interferon-gamma(IFN) and bacterial lipopolysaccharide (LPS) generates reactive oxygen and nitrogen species leading to DNA damage, lipid oxidation, and tocopherol oxidation. The tocopherols possess unique chemical and biological properties that suggest they have important roles related to intracellular defense against radical-mediated damage.Despite increased levels of reactive oxidants and decreased media tocopherol, cellular levels of gamma-tocopherol, but not alpha-tocopherol, were observed to increase significantly when cells were treated with IFN/LPS. Inhibition of nitric oxide (NO) synthesis by a specific inhibitor of inducible NO synthase (iNOS) increased both intracellular alpha-tocopherol and gamma-tocopherol concentrations, but did not significantly alter the reduction in media tocopherol levels caused by IFN/LPS treatment. Both exposure to exogenous NO and cellular synthesis of NO in cell culture increased media levels of 8-epi-prostaglandin F2alpha, a marker of oxidative lipid damage, whereas inhibition of endogenous NO synthesis reduced media 8-epi-prostaglandin F2alpha formation to control levels.Elevated intracellular levels of gamma-tocopherol in response to the cellular inflammatory state may indicate that it serves a unique role in minimizing cellular damage resulting from endogenous NO synthesis. Results of the current study suggest that NO is an important mediator of damage within the cell, as well as in the oxidation of both alpha- and gamma-tocopherols. The paradoxical increase in cellular tocopherol associated with the induction of NO synthesis may indicate either enhanced cellular transport/decreased export for tocopherols or recruitment of free tocopherol from tocopherol storage molecules
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