Publications by authors named "Atsuko Yamazaki"

The diversity of organism morphology is heavily dependent on the evolution of gene regulatory networks. However, the mechanistic basis on which change can be incorporated within these systems remains poorly understood. Evolution of the echinoderm hesC gene as a novel upstream mesoderm regulator found uniquely in the euechinoid sea urchin lineage is an intriguing example of gene regulatory network modification.

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The 1997/1998 El Niño event caused mass coral bleaching and mortality in many tropical and subtropical regions, including corals on Green Island, Taiwan, in the northwestern Pacific Ocean. This study analyzed coral carbon isotope ratios (δC), oxygen isotope ratios (δO), and Sr/Ca ratios for 29 years, including the 1997/1998 El Niño period, to examine how high water temperature events are recorded in coral geochemical indicators. Sr/Ca ratios in coral skeletons from Green Island show the lowest peak, means the highest temperature during the 1997/1998 El Niño period.

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Article Synopsis
  • Research on sea urchin embryos reveals that tissue-specific effector genes start being expressed earlier and more dynamically than previously thought, challenging the traditional view of differentiation as a strictly linear process.
  • The study shows that some effector genes are activated even before cell lineages separate, indicating a more complex regulatory interaction during embryonic development.
  • This new understanding suggests that differentiation should be viewed as a continuous accumulation of gene expression, which may provide insights into the evolution of new cell types.
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The Mekong River Delta (MRD) is an essential agricultural area for the worldwide rice supply. Floods and droughts triggered by El Niño southern oscillation (ENSO) have been threatening sustenance in the MRD. Sustainable food supplies require understanding the response of the MRD hydrology to the changing ENSO behaviour in recent decades.

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The larval skeleton of the echinoderm is believed to have been acquired through co-option of a pre-existing gene regulatory network (GRN); that is, the mechanism for adult skeleton formation in the echinoderm was deployed in early embryogenesis during echinoderm diversification. To explore the evolutionary changes that occurred during co-option, we examined the mechanism for adult skeletogenesis using the starfish Patiria pectinifera. Expression patterns of skeletogenesis-related genes (vegf, vegfr, ets1/2, erg, alx1, ca1, and clect) suggest that adult skeletogenic cells develop from the posterior coelom after the start of feeding.

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Sea urchin embryos have been one of model organisms to investigate cellular behaviors because of their simple cell composition and transparent body. They also give us an opportunity to investigate molecular functions of human proteins of interest that are conserved in sea urchin. Here we report that human disease-associated extracellular matrix orthologues ECM3 and QBRICK are necessary for mesenchymal cell migration during sea urchin embryogenesis.

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Article Synopsis
  • Early embryogenesis in model animals, particularly sea urchins, is controlled by specific lineage genes, such as Pmar1, which plays a key role in endomesoderm specification.* -
  • The study also identifies a basal echinoid gene that influences endomesoderm development without repressing the HesC gene, unlike Pmar1 in modern urchins.* -
  • Findings suggest that Pmar1 evolved to mimic the regulatory function of another protein, Phb, while the gene HesC was later added to the regulatory network in the euechinoid lineage, shedding light on the evolution of developmental processes.*
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The specification of anterior neuroectoderm is controlled by a highly conserved molecular mechanism in bilaterians. A forkhead family gene, foxQ2, is known to be one of the pivotal regulators, which is zygotically expressed in this region during embryogenesis of a broad range of bilaterians. However, what controls the expression of this essential factor has remained unclear to date.

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This chapter describes practical methods and key points for using non-camarodont echinoids including cidaroids (Order Cidaroida), clypeasteroids (also known as sand dollars; Order Clypeasteroida), and spatangoids (also known as heart urchins; Order Spatangoida) as experimental subjects for biological studies. The content described here is based on six Japanese species of echinoids (Astriclypeus manni, Clypeaster japonicus, Echinocardium cordatum, Peronella japonica, Prionocidaris baculosa, and Scaphechinus mirabilis). Specific topics addressed in this chapter include the collection and maintenance of adults, embryonic culture, and experimental procedures for micromanipulations, whole mount in situ hybridization, and immunological experiments.

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Article Synopsis
  • The Indian Ocean Dipole (IOD) has become more intense due to global warming, but its behavior during the global-warming hiatus from the late 1990s to 2015 is not well understood.
  • A 26-year study of coral from the Gulf of Oman revealed a major shift in 1999, indicating increased upwelling in the region, which altered the typical IOD pattern.
  • This change suggests that during the hiatus, stronger Walker circulation affected upwelling in the Western Indian Ocean, leading to a disconnect from the IOD dynamics.
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Precise body axis formation is an essential step in the development of multicellular organisms, for most of which the molecular gradient and/or specifically biased localization of cell-fate determinants in eggs play important roles. In sea urchins, however, any biased proteins and mRNAs have not yet been identified in the egg except for vegetal cortex molecules, suggesting that sea urchin development is mostly regulated by uniformly distributed maternal molecules with contributions to axis formation that are not well characterized. Here, we describe that the maternal Meis transcription factor regulates anterior-posterior axis formation through maintenance of the most anterior territory in embryos of a sea urchin, Hemicentrotus pulcherrimus.

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We used a high-resolution oxygen isotope (δO), carbon isotope (δC) and Sr/Ca ratios measured in the skeleton of a reef-building coral, Porites sp., to reveal seasonal-scale upwelling events and their interannual variability in the Gulf of Oman. Our δC record shows sharp negative excursions in the summer, which correlate with known upwelling events.

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A 23-year-old woman presented with a persistent fever and shortness of breath. Computed tomography showed marked pericardial effusion, hepatosplenomegaly, and cervical and mediastinal lymph node swelling. Epstein-Barr virus (EBV) antibody titers were abnormally elevated, and the copy number of EBV-DNA was increased in peripheral blood.

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Article Synopsis
  • To investigate the roles of the genes hesC and gcm in echinoid larval development, experiments were conducted on two different species of euechinoids, revealing that inhibiting hesC increases larval mesenchyme cell numbers.
  • Inhibition of gcm was confirmed to play a role in the differentiation of pigment cells.
  • Simultaneous blocking of both genes leads to more skeletogenic cells, indicating that gcm helps prevent skeletogenic cell development.
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Severe acute lung injury is a rare but life-threatening complication associated with bortezomib. We report a patient with multiple myeloma who developed a severe diffuse alveolar hemorrhage (DAH) immediately after the first bortezomib administration. The patient was suspected to have pulmonary involvement of myeloma, which caused DAH after rapidly eradicating myeloma cells in the lungs with bortezomib.

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Immunosuppressive therapy (IST) with a combination of antithymocyte globulin (ATG) and cyclosporine (CsA) is an effective therapeutic modality for patients with aplastic anemia (AA) who are not eligible for allogeneic stem cell transplantation (Allo-SCT) from a human leukocyte antigen-identical sibling donor. However, there have been reports of some patients developing lymphoproliferative disorder (LPD) after IST for AA. We herein report a case of a 26-year-old man with severe AA (SAA) complicated by LPD after a single course of IST, who was successfully treated with Allo-SCT from an unrelated donor.

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Article Synopsis
  • The study focuses on mesenchyme cell specification mechanisms in two non-Camarodonta echinoids, revealing unique and shared gene expression patterns.
  • Some expression traits in Glyptocidaris crenularis and Echinocardium cordatum differ from those in Camarodonta, implying evolutionary divergence.
  • Notably, the expression of ets1 in E. cordatum's aboral ectoderm may correlate with the development of a new larval structure, hinting at significant evolutionary changes in echinoid development.
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Acute myeloid leukemia (AML) with mixed lineage leukemia-eleven-nineteen lysine-rich leukemia (MLL-ELL) is a rare subtype of MLL-rearranged AML. The outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with this disease remains unknown. In the present study, we retrospectively investigated the efficacy of allo-HSCT in eight adult MLL-ELL-positive AML patients.

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Sea urchins are model non-chordate deuterostomes, and studying the nervous system of their embryos can aid in the understanding of the universal mechanisms of neurogenesis. However, despite the long history of sea urchin embryology research, the molecular mechanisms of their neurogenesis have not been well investigated, in part because neurons appear relatively late during embryogenesis. In this study, we used the species Temnopleurus reevesii as a new sea urchin model and investigated the detail of its development and neurogenesis during early embryogenesis.

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Echinoids (sea urchins) are divided into two major groups - cidaroids (a 'primitive' group) and euechinoids (a 'derived' group). The cidaroids are a promising model species for understanding the ancestral developmental mechanisms in echinoids, but little is known about the molecular mechanisms of cidaroid development. In euechinoids, skeletogenic mesenchyme cell specification is regulated by the double-negative gate (DNG), in which hesC represses the transcription of the downstream mesenchyme specification genes (alx1, tbr and ets1), thereby defining the prospective mesenchyme region.

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Myeloid sarcoma (MS) is an extramedullary myeloid tumor that sometimes presents with antedating systemic leukemia, leading physicians to the misdiagnosis of lymphoma. CD25 is expressed in 13% of patients with acute myeloid leukemia (AML), and its expression is associated with FLT3-ITD mutations, an elevated serum soluble interleukin 2 receptor (sIL-2R) level and a lower survival rate. However, there are no reports concerning the relationship between MS and the CD25 expression.

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LR11, also known as SorLA or SORL1, is a type-I membrane protein from which a large extracellular part, soluble LR11 (sLR11), is released by proteolytic shedding on cleavage with a disintegrin and metalloproteinase 17 (ADAM17). A shedding mechanism is presumed to have a key role in the functions of LR11, but the evidence for this has not yet been demonstrated. Tetraspanin CD9 has been recently shown to regulate the ADAM17-mediated shedding of tumor necrosis factor-α and intercellular adhesion molecule-1 on the cell surface.

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