Enamines are key intermediates in both organic chemistry and enzyme catalysis. We have developed designer proteins and small peptides that catalyze aldol, retro-aldol, and Michael reactions, in which catalyst molecules form enamines from aldehydes and ketones in situ. We have also developed small amine- and amino acid-catalyzed enamine-based bond-forming reactions that can be performed under mild conditions. In this review, I summarize our strategies for the development of designer catalysts and catalyzed reactions that use enamines as key intermediates.

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Continued and substantial growth of islet tissue occurs after birth in rodents and humans, with additional compensatory growth in response to increased demand. In rodents there is clear evidence of pancreatic regeneration after some types of injury, with proliferation of pre-existing differentiated cell types accounting for some replacement. Additionally, neogenesis has been reported. However, the existence and identity of a progenitor cell has been debated. We hypothesized that the stem cells are duct epithelial cells that after replication undergo a regression to a less differentiated state and can then form new endocrine and exocrine pancreas. To directly test whether ductal cells serve as pancreatic progenitors after birth and give rise to new islets, we generated transgenic mice expressing human carbonic anhydrase II (CAII) promoter: Cre or inducible Cre-estrogen receptor to cross with ROSA beta geo26 (ROSA26) reporter mice (ROSA26-loxP-stop-loxP-lacZ; in the cells that Cre is expressed, loxP will be cut out and allows LacZ to be expressed). We show that CAII-expressing cells within the pancreas act as progenitors that give rise to both new islets and acini normally after birth and after injury.

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This paper is a historical review of the fixation methods and techniques, for closer and more detailed observation of the ultrastructure of budding yeast Saccharomyces cerevisiae, which we developed with the use of transmission electron microscopy. In our study “Low-Voltage Scanning Electron Microscopy” (LVSEM) was used for uncoated biological specimens and “High-Pressure Freezing · Ultra-Low Temperature/LVSEM” for multi-purpose observation. These methods and techniques enabled us to observe more closely, and analyze with greater precision, the fine structures of yeast cells. This led to studies of cell wall formation from the reverting protoplast of the fission yeast Schizosaccharomyces pombe and its cell division; and of the correlation between cell wall formation and actin cytoskeleton. Further, we present some of the most recent achievements in the use of a new technique for visualizing the molecular structure of yeast cell wall components, using focused ion beam and micro-sampling which were applied to biological specimens. Our success in the visualization of the arrowhead structure of the F-actin in the fission yeast cell, by using myosin S1 decoration, enabled us to clarify the role of actin cytoskeleton during cell division and cell wall formation. Finally we discuss potential future studies of the yeast.

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We have found glucose-containing glycerophospholipid, phosphatidylglucoside (PtdGlc) in mammalian tissure. PtdGlc is highly expressed in developing rodent brain in cell type- and stage-specific manner. PtdGlc consists of single molecular species with C18:0 at glycerol sn-1 and C20:0 at glycerol sn-2 position and by this saturated fatty acyl composition, PtdGlc is a resident of membrane lipid microdomain (raft). Stimulation of PtdGlc-containing lipid raft on neuroepithelial cells causes astroglial differentiation accompanied with activation of EGF-receptor and Jac-Stat signaling pathway. In addition, PtdGlc forms water-soluble lyso-PtdGlc (LPG) by action of phospholipase A2 and LPG act on neuron growth cone to induce collapse and chemorepulsion. Taken together, PtdGlc is new bioactive lipid produced in radial/astroglia and act on neuron mediated by LPG.

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Accumulating data strongly suggest that prostaglandin E₂ (PGE₂) exerts a variety of bioactivity in articular chondrocytes via its receptors (EP receptors). In addition, it has been suggested that isoforms of the EP receptor, e.g. EP2 and EP4, play specific roles in matrix turnover in the cartilage, as well as chondrocyte differentiation and chondrogenesis. Here, we summarize recent reports on EP receptor expression and its potential role in articular chondrocytes and focus on its potential role in the pathophysiology of human osteoarthritis.

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This report examines RIKEN's efforts to support women researchers and promote better work-life balance for all employees. It evaluates the effectiveness of these efforts, and outlines the issues and problems that have arisen in the process.

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