The change of terminus and ice velocity field and grounding line estimation in Langhovde Glacier, Antarctica.

第3回極域科学シンポジウム　横断セッション「海・陸・氷床から探る後期新生代の南極寒冷圏環境変動」11月27日（火） 国立国語研究所 ２階講

Hot water drilling and measurements beneath the grounding zone of Langhovde Glacier, East Antarctica

第3回極域科学シンポジウム　横断セッション「海・陸・氷床から探る後期新生代の南極寒冷圏環境変動」11月27日（火） 国立国語研究所 ２階講

The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.

X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution

Dual modulation of the T-cell receptor-activated signal transduction pathway by morphine in human T lymphocytes.

[Purpose]In this study, we aimed to investigate the effect of morphine on the activation of extracellular signal-regulated kinase (ERK) and nuclear factor-κB (NF-κB), both of which play crucial roles in T-cell activation. [Methods]Human CD3+ T cells and Jurkat T cells were stimulated by anti-CD3 antibody or phorbol 12-myristate 13-acetate plus ionomycin with or without 24-h pretreatment with morphine. Activation of ERK was assessed by immunoblot analysis of phosphorylated ERK. Activation of the NF-κB signaling pathway was examined by analyzing nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation using immunoblotting, and interleukin-2 (IL-2) gene expression using quantitative real-time reverse-transcriptase polymerase chain reaction. [Results]Morphine pretreatment enhanced ERK phosphorylation, but inhibited IκBα phosphorylation and IL-2 gene expression in activated T cells. The effects of morphine on ERK phosphorylation and IL-2 gene expression were not antagonized by naloxone. We detected κ-opioid receptor transcript in T cells, but U50, 488, a κ-receptor-selective agonist, did not enhance ERK phosphorylation. [Conclusion]Morphine enhances ERK signaling, whereas it inhibits NF-κB signaling in activated human T cells. These effects of morphine are unlikely to be mediated by known opioid receptors

Active water exchange and life near the grounding line of an Antarctic outlet glacier

The grounding line (GL) of the Antarctic ice sheet forms the boundary between grounded and floating ice along the coast. Near this line, warm oceanic water contacts the ice shelf, producing the ice sheet's highest basal-melt rate. Despite the importance of this region, water properties and circulations near the GL are largely unexplored because in-situ observations are difficult. Here we present direct evidence of warm ocean-water transport to the innermost part of the subshelf cavity (several hundred meters seaward from the GL) of Langhovde Glacier, an outlet glacier in East Antarctica. Our measurements come from boreholes drilled through the glacier's similar to 400-m-thick grounding zone. Beneath the grounding zone, we find a 10-24-m-deep water layer of uniform temperature and salinity (-1.45 degrees C; 34.25 PSU), values that roughly equal those measured in the ocean in front of the glacier. Moreover, living organisms are found in the thin subglacial water layer. These findings indicate active transport of water and nutrients from the adjacent ocean, meaning that the subshelf environment interacts directly and rapidly with the ocean. (C) 2014 The Authors. Published by Elsevier B.V

Glacier flow measurement and radio-echo sounding at Aurora Peak, Alaska, in 2008

As part of a deep ice-core drilling project, GPS and ice-radar measurements were made in the vicinity of Aurora Peak, Alaska, USA. Surface and bed elevation maps were obtained over an area of 400 m x 700 m, which includes the drilling site. Surface flow velocity was measured at 18 locations in the same area. The results showed that the drilling site was situated on a gentle north-south ridge with saddle-shaped surface geometry. The horizontal ice-flow velocity at the drilling site was <0.5 m a^[-1] and the ice generally flowed eastward and westward along the surface slope. The glacier bed slopes to the east and has more complex topography than the ice surface. The drilling site was situated above a bedrock dip, with an ice thickness of 252 ± 10 m. These data constitute important information for estimating the effect of ice flow to the ice core retrieved from the depth of up to 180.17 m

Analytical study on the growth and transfer of adhesive substances generated on the surface in the early stage of sliding

This study is intended to produce reliable quantitative information about adhesive wear phenomena of metallic materials in the early stage of dry sliding. The outcome of this study will contribute to the refinement of the physical model of a wear mechanism. A devised technical method was employed in the study to enable data acquisition linked with the position of measurement on the specimen and objective combinational analyses of plural kinds of tribological data. Quantitative analyses on the relationship between friction force and specimen displacement perpendicular to the sliding surface was carried out. Data analyses on the self-mated dry sliding of austenitic stainless steel clarified the existence of several elemental processes of adhesive mechanism with quantitative parameters such as the growth rate and the size of adhesive substances generated at the interface between sliding members. The influences of the relative humidity (RH) in an atmospheric air on the numerical parameters were revealed as well and they were interpreted into the physical model of the adhesive wear mechanism