Variations of divalent cation concentrations in pore water and the precipitation of Mg-rich authigenic mineral during early diagenesis of Toyoma Formation

The variations of Fe, Mn and Mg concentrations in pore water were deduced from the chemistry of calcite. With depth, the Fe/Ca, Mn/Ca, Mg/Ca ratios of pore water decrease. The decrease in the Fe/Ca ratio is due to the precipitation of pyrite, whereas the decrease in the Mn/Ca ratio is due to the precipitation of Mn-rich calcite. The depletion of Mg in pore water is ascribed to the precipitation of either Mg-rich smectite or Mg-rich chlorite. A-type rock is further divided into A1 and A2 subtypes, on the basis of δ13C. Excesses of MgO and deficiencies of K舀 O above the calculated whole-rock compositions are observed mainly in the phosphatic nodules and A1 subtype. This suggests that the formation of Mg-rich smectite or Mg-rich chlorite took place at very early stage of diagenesis of the Toyoma Formation.Article信州大学理学部紀要 38: 23-34(2004)departmental bulletin pape

Characterization of somatic embryogenesis initiated from the Arabidopsis shoot apex

Somatic embryogenesis is one of the best examples of the remarkable developmental plasticity of plants, in which committed somatic cells can dedifferentiate and acquire the ability to form an embryo and regenerate an entire plant. In Arabidopsis thaliana, the shoot apices of young seedlings have been reported as an alternative tissue source for somatic embryos (SEs) besides the widely studied zygotic embryos taken from siliques. Although SE induction from shoots demonstrates the plasticity of plants more clearly than the embryo-to-embryo induction system, the underlying developmental and molecular mechanisms involved are unknown. Here we characterized SE formation from shoot apex explants by establishing a system for time-lapse observation of explants during SE induction. We also established a method to distinguish SE-forming and non-SE-forming explants prior to anatomical SE formation, enabling us to identify distinct transcriptome profiles of these two explants at SE initiation. We show that embryonic fate commitment takes place at day 3 of SE induction and the SE arises directly, not through callus formation, from the base of leaf primordia just beside the shoot apical meristem (SAM), where auxin accumulates and shoot-root polarity is formed. The expression domain of a couple of key developmental genes for the SAM transiently expands at this stage. Our data demonstrate that SE-forming and non-SE-forming explants share mostly the same transcripts except for a limited number of embryonic genes and root genes that might trigger the SE-initiation program. Thus, SE-forming explants possess a mixed identity (SAM, root and embryo) at the time of SE specification

The genesis of phosphatic and carbonate rocks in the Toyoma Formation, Northeastern Japan

Various phosphatic and carbonate rocks occur in the Upper Permian Toyoma Formation. They are classified into phosphatic nodules, A-, B-and C-type rocks.The isotopic ratios of whole-rock calcite,pyrite and apatite in the rocks and the results of pyrite microanalysis using a high-resolution secondary ion mass spectrometer are presented. The carbon and sulfur isotopic compositions indicate that the rocks were formed through microbial sulfate reduction. Three distinct zones have been recognized within the Toyoma Formation that define its early diagenesis. The three zones’compositions differ in their mole fractions of authigenic material and the δ13C of their calcite deposits. Zone 1 is the region of oxic surface sediment in which sulfur-oxidizing bacteria grew.Because sulfuric acid is generated by the chemosynthesis of the bacteria, biogenic phosphate debris such as fish bones and scales were dissolved.The phosphate ions thus formed were the source of the phosphatic rocks of the Toyoma Formation.Zone 2 is the anoxic zone that underlay Zone 1. Anaerobic sulfate-reducing bacteria grew in this zone, resulting in increased pore water alkalinity and the precipitation of pyrite and apatite. Phosphatic nodules and A-and B-type rocks began to grow in this zone.Zone 3 is characterized by calcite precipitation. The pore water, saturated with calcite components, segregated from the sediments into rocks allowing the rocks to be calcareous. As sediments became buried deeper and deeper, they experienced the conditions of each successive zone. However, the period of final consolidation of the rocks differed from one rock type to another as evidenced by the varying δ1C values for calcite contained in the different rock types. Although the rocks are mixtures of authigenic minerals originating in different zones, it was possible to estimate the range of diagenetic zones in which each rock type was formed.ArticleJournal of the Faculty of Science Shinshu University 44: 1-57(2012)departmental bulletin pape

Development of bed-building behaviors in captive chimpanzees (Pan troglodytes): Implication for critical period hypothesis and captive management

Wild great apes build beds for sleeping by combining tree branches or other vegetation, but the development of this behavior is poorly understood. We investigated the development of bed-building behaviors by conducting complementary cross-sectional and longitudinal studies of captive chimpanzees. In the cross-sectional study, we created an ethogram of behaviors related to bed-building by observing 59 chimpanzees living at the Kumamoto Sanctuary, Kyoto University, and the Kyoto City Zoo. In the longitudinal study, we installed bed-building platforms, provided branches on the platforms on a regular basis, and recorded behaviors of five chimpanzees (including an infant born in 2013) over a 3-year period from February 2015 to February 2018 at the Kyoto City Zoo (total 490.7 h). We found that all the chimpanzees performed some form of bed-building behavior but wild-born chimpanzees possessed more sophisticated techniques than captive-born chimpanzees. We also found that although the offspring of a wild-born female only showed simple techniques at the beginning of the longitudinal study, his repertoire of bed-building behaviors became as complex as that of his mother by the age of five. Our results suggest that improved bed-building behaviors can be supported in captive-born great apes by providing learning opportunities during appropriate stages of development

Aldo–Keto Reductase 1B10 and Its Role in Proliferation Capacity of Drug-Resistant Cancers

The human aldo–keto reductase AKR1B10, originally identified as an aldose reductase-like protein and human small intestine aldose reductase, is a cytosolic NADPH-dependent reductase that metabolizes a variety of endogenous compounds, such as aromatic and aliphatic aldehydes and dicarbonyl compounds, and some drug ketones. The enzyme is highly expressed in solid tumors of several tissues including lung and liver, and as such has received considerable interest as a relevant biomarker for the development of those tumors. In addition, AKR1B10 has been recently reported to be significantly up-regulated in some cancer cell lines (medulloblastoma D341 and colon cancer HT29) acquiring resistance toward chemotherapeutic agents (cyclophosphamide and mitomycin c), suggesting the validity of the enzyme as a chemoresistance marker. Although the detailed information on the AKR1B10-mediated mechanisms leading to the drug resistance process is not well understood so far, the enzyme has been proposed to be involved in functional regulations of cell proliferation and metabolism of drugs and endogenous lipids during the development of chemoresistance. This article reviews the current literature focusing mainly on expression profile and roles of AKR1B10 in the drug resistance of cancer cells. Recent developments of AKR1B10 inhibitors and their usefulness in restoring sensitivity to anticancer drugs are also reviewed

A New Disorder in UV-Induced Skin Cancer with Defective DNA Repair Distinct from Xeroderma Pigmentosum or Cockayne Syndrome

We report the characterization of a Japanese woman who exhibited many freckles and skin cancers in sun-exposed areas, but displayed no photosensitivity. Fibroblasts (KPSX7) derived from this patient showed similar UV sensitivity to that of normal human fibroblasts. The KPSX7 cells showed normal levels of unscheduled DNA synthesis, recovery of RNA synthesis, recovery of replicative DNA synthesis, protein-binding ability to UV-damaged DNA, and post-translational modification of xeroderma pigmentosum (XP) C. These results indicate that the patient had neither XP nor Cockayne syndrome. Although these results suggest that the KPSX7 cells were proficient in nucleotide excision repair activity, host-cell reactivation (HCR) activity of KPSX7 cells was reduced. Furthermore, introduction of UV damage endonuclease into the cells restored repair activity in the HCR assay to almost normal levels. These results indicate that KPSX7 cells are defective for some types of repair activity in UV-damaged DNA. In summary, the patient had a previously unknown disorder related to UV-induced carcinogenesis, with defective DNA repair

Impact of Energetic Ion Driven Global Modes on Toroidal Plasma Confinements

Excitation of energetic-ion-driven Alfv6n eigenmodes (AEs) and their impact on energetic ion confinement are widely and intensively studied in helical devices such as CHS and LHD as well as major tokamaks. The excitation of AEs sensitively depends on the parameter space defined by the averaged beam beta and the velocity ratio V6nlV6 (V611 : injected beam ion velocity, Va: Alfv6n velocity). In LHD, these two relevant parameters are widely scanned without suffering from current disruptions. So far, toroidicity induced AE (TAE), global AE (GAE) and energetic particle mode (EPM) or resonant TAE (R-TAE) were identified during tangential neutral beam injection (NBI) in CHS and LHD. Moreover, a new coherent mode with the frequency by about 8 times higher than the TAE frequency was observed in NBI heated plasmas of LHD at low magnetic field (<0.6T). This mode may be induced by helical field components of the confinement field. Nonlinear phenomena of bursting amplitude modulation and fast frequency chirping are clearly seen for TAEs and EPMs in CHS and LHD. EPMs in CHS and bursting TAEs in LHD enhance radial transport of energetic ions in certain plasma conditions