Study on Mechanism of Caisson Type Sea Wall Movement During Earthquakes

Model vibration tests under gravity and centrifuge model vibration tests in 50G were performed to investigate the behavior of caisson type sea mill with reclaimed ground below and behind the caisson. In the tests, sliding of caisson occurred only during excitation, which indicates that it is impossible to predict the displacement of caisson and the deformation of back-fill ground without taking account of both inertia force of caisson and dynamic earth pressure. As for the dynamic earth pressure acts on the caisson, it was found that when input acceleration is small, the dynamic earth pressure seems to restrain the movement of caisson and the excess pore water pressure hardly occurs. On the other hand, when input acceleration is large enough to cause liquefaction, the dynamic earth pressure seems to promotes the movement of caisson

Application of spherical substrate to observe bacterial motility machineries by Quick-Freeze-Replica Electron Microscopy

3-D Structural information is essential to elucidate the molecular mechanisms of various biological machineries. Quick-Freeze Deep-Etch-Replica Electron Microscopy is a unique technique to give very high-contrast surface profiles of extra- and intra-cellular apparatuses that bear numerous cellular functions. Though the global architecture of those machineries is primarily required to understand their functional features, it is difficult or even impossible to depict side- or highly-oblique views of the same targets by usual goniometry, inasmuch as the objects (e.g. motile microorganisms) are placed on conventional flat substrates. We introduced silica-beads as an alternative substrate to solve such crucial issue. Elongated Flavobacterium and globular Mycoplasmas cells glided regularly along the bead\u27s surface, similarly to those on a flat substrate. Quick-freeze replicas of those cells attached to the beads showed various views; side-, oblique- and frontal-views, enabling us to study not only global but potentially more detailed morphology of complicated architecture. Adhesion of the targets to the convex surface could give surplus merits to visualizing intriguing molecular assemblies within the cells, which is relevant to a variety of motility machinery of microorganisms

Histone Chaperone Asf1 Plays an Essential Role in Maintaining Genomic Stability in Fission Yeast

The histone H3-H4 chaperone Asf1 is involved in chromatin assembly (or disassembly), histone exchange, regulation of transcription, and chromatin silencing in several organisms. To investigate the essential functions of Asf1 in Schizosaccharomyces pombe, asf1-ts mutants were constructed by random mutagenesis using PCR. One mutant (asf1-33(ts)) was mated with mutants in 77 different kinase genes to identify synthetic lethal combinations. The asf1-33 mutant required the DNA damage checkpoint factors Chk1 and Rad3 for its survival at the restrictive temperature. Chk1, but not Cds1, was phosphorylated in the asf1-33 mutant at the restrictive temperature, indicating that the DNA damage checkpoint was activated in the asf1-33 mutant. DNA damage occured in the asf1-33 mutant, with degradation of the chromosomal DNA observed through pulse-field gel electrophoresis and the formation of Rad22 foci. Sensitivity to micrococcal nuclease in the asf1-33 mutant was increased compared to the asf1+ strain at the restrictive temperature, suggesting that asf1 mutations also caused a defect in overall chromatin structure. The Asf1-33 mutant protein was mislocalized and incapable of binding histones. Furthermore, histone H3 levels at the centromeric outer repeat region were decreased in the asf1-33 mutant and heterochromatin structure was impaired. Finally, sim3, which encodes a CenH3 histone chaperone, was identified as a strong suppressor of the asf1-33 mutant. Taken together, these results clearly indicate that Asf1 plays an essential role in maintaining genomic stability in S. pombe

Lgals9 deficiency ameliorates obesity by modulating redox state of PRDX2

The adipose tissue is regarded as an endocrine organ and secretes bioactive adipokines modulating chronic inflammation and oxidative stress in obesity. Gal-9 is secreted out upon cell injuries, interacts with T-cell immunoglobulin-3 (Tim-3) and induces apoptosis in activated Th1 cells. Gal-9 also binds to protein disulfide isomerase (PDI), maintains PDI on surface of T cells, and increases free thiols in the disulfide/thiol cycles. To explore the molecular mechanism of obesity, we investigated Gal-9(-/-) and Gal-9(wt/wt) C57BL/6J mice fed with high fat-high sucrose (HFHS) chow. Gal-9(-/-) mice were resistant to diet-induced obesity associated with reduction of epididymal and mesenteric fat tissues and improved glucose tolerance compared with Gal-9(wt/wt) mice. However, the number of M1, M2 macrophages, and M1/M2 ratio in epididymal fat were unaltered. Under HFHS chow, Gal-9(-/-) mice receiving Gal-9(-/-) or Gal-9(wt/wt) bone marrow-derived cells (BMCs) demonstrated significantly lower body weight compared with Gal-9(wt/wt) mice receiving Gal-9(-/-) BMCs. We identified the binding between Gal-9 and peroxiredoxin-2 (PRDX2) in sugar chain-independent manner by nanoLC-MS/MS, immunoprecipitation, and pull-down assay. In 3T3L1 adipocytes, Gal-9 knockdown shifts PRDX2 monomer (reduced form) dominant from PRDX2 dimer (oxidized form) under oxidative stress with H2O2. The inhibition of Gal-9 in adipocytes may be a new therapeutic approach targeting the oxidative stress and subsequent glucose intolerance in obesity