Deciphering molecular mechanisms that regulate programmed cell death of primordial germ cells in Drosophila melanogaster

Programmed cell death (PCD) is a genetically regulated process that is central to life of multicellular organisms. During development, PCD serves to sculpt tissues, remove temporary structures, regulate cell populations, and eliminate harmful cells. Deregulation of PCD can lead to medical conditions such as cancer and neurodegenerative disorders. Core components of PCD machineries are conserved across the animal phyla. Therefore, studies in model organisms provide valuable insights for further understanding of this very important process. The research presented here uses Drosophila primordial germ cells as a model system to investigate genes that are important for germ cell PCD. During embryogenesis, approximately 50% of germ cells that initially form are efficiently eliminated via PCD. However, mechanisms by which germ cells undergo PCD remain unknown. We have identified the outsiders (out) gene is essential for germ cell PCD. Initial characterization of out mutants revealed that out is required zygotically for germ cell PCD. out is predicated to encode a monocarboxylate transporter. In addition, genetic approaches were taken to investigate involvement of other known cell death regulators in germ cell PCD and their possible interactions with out. We examined the two prominent PCD machineries, apoptosis and autophagy, in germ cell PCD. Our observations showed that germ cell death in wild-type embryos is independent of potent pro-apoptotic genes, grim, reaper, hid, and caspase Dronc. Studies of several autophagy mutants did not result in severe germ cell phenotype. Our observations suggest that blocking one mode of PCD may not be enough to stop germ cell elimination. These findings have allowed elucidating of more accurate molecular model for germ cell PCD

Search by a Metamorphic Robotic System in a Finite 3D Cubic Grid

We consider search in a finite 3D cubic grid by a metamorphic robotic system (MRS), that consists of anonymous modules. A module can perform a sliding and rotation while the whole modules keep connectivity. As the number of modules increases, the variety of actions that the MRS can perform increases. The search problem requires the MRS to find a target in a given finite field. Doi et al. (SSS 2018) demonstrate a necessary and sufficient number of modules for search in a finite 2D square grid. We consider search in a finite 3D cubic grid and investigate the effect of common knowledge. We consider three different settings. First, we show that three modules are necessary and sufficient when all modules are equipped with a common compass, i.e., they agree on the direction and orientation of the x, y, and z axes. Second, we show that four modules are necessary and sufficient when all modules agree on the direction and orientation of the vertical axis. Finally, we show that five modules are necessary and sufficient when all modules are not equipped with a common compass. Our results show that the shapes of the MRS in the 3D cubic grid have richer structure than those in the 2D square grid

P-Wave Charmed-Strange Mesons

We examine charmed-strange mesons within the framework of the constituent quark model, focusing on the states with L=1. We are particularly interested in the mixing of two spin-states that are involved in $D_{s1}(2536)$ and the recently discovered $D_{sJ}(2460)$. We assume that these two mesons form a pair of states with J=1. These spin-states are mixed by a type of the spin-orbit interaction that violates the total-spin conservation. Without assuming explicit forms for the interactions as functions of the interquark distance, we relate the matrix elements of all relevant spin-dependent interactions to the mixing angle and the observed masses of the L=1 quartet. We find that the spin-spin interaction, among various types of the spin-dependent interactions, plays a particularly interesting role in determining the spin structure of $D_{s1}(2536)$ and $D_{sJ}(2460)$

「逆さまの世界」としてのヘーゲル哲学 : 矛盾と反復の論理学

学位の種別:課程博士University of Tokyo(東京大学

Synthesis of analogs of wasabi phytoalexin (methyl 1-methoxyindole-3-carboxylate)

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部Syntheses of wasabi phytoalexin analogs, such as 6-bromo-5-iodo, 2-bromo-5-iodo, 6-nitro, 5-chloroacetyl, and 6-chloroacetyl congeners, are reported. An interesting effect of the 1-methoxy group on the regioselectivity of electrophilic substitution reactions on indole nucleus is observed