Keisuke Shimada

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The histone H2A.Z variant is widely conserved among eukaryotes. Two isoforms, H2A.Z.1 and H2A.Z.2, have been identified in vertebrates and may have distinct functions in cell growth and gene expression. However, no structural differences between H2A.Z.1 and H2A.Z.2 have been reported. In the present study, the crystal structures of nucleosomes containing(More)
The repeated-dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect hepatocarcinogens. We conducted a collaborative study to assess the performance of this assay and to evaluate the possibility of integrating it into general toxicological studies. Twenty-four testing laboratories belonging to the Mammalian Mutagenicity(More)
Species in the wood-feeding genus Salganea within the cockroach subfamily Panesthiinae (Blaberidae) typically live in biparental families; their first instars suffer high mortality when removed from adults, and in at least one species, adults are known to feed neonates on oral liquids. In the closely related gregarious wood-feeding genus Panesthia , no(More)
Beta-glucosidase (BG) is known as a multifunctional enzyme for social maintenance in terms of both cellulose digestion and social communication in termites. However, the expression profiles of each BG gene and their evolutionary history are not well understood. First, we cloned two types of BG homologs (RsBGI and RsBGII) from the termite Reticulitermes(More)
The unique feature of eusociality is reproductive division of labor. At the termite colony initiation stage, there are only reproductives plus larvae and eggs that need to be cared for. As workers increase in number with colony development, reproductives are thought to be relieved of the cost of brood care and able to resume reproduction. This transition of(More)
The repeated-dose liver micronucleus (RDLMN) assay has been previously reported to be effective for the detection of hepatocarcinogens and suitable for general toxicology studies. A collaborative study was conducted to evaluate whether this RDLMN assay using young adult rats without collagenase perfusion of the liver can be used to detect genotoxic(More)
This paper describes a user simulator based on analysis of VoiceXML description. A user simulator is a method to evaluate a spoken dialog system without the use of human evaluators. The new feature of our simulator is that it uses a VoiceXML description that describes the dialog system’s behavior. By using the VoiceXML description, the proposed simulator(More)
In termites, division of labor among castes, categories of individuals that perform specialized tasks, increases colony-level productivity and is the key to their ecological success. Although molecular studies on caste polymorphism have been performed in termites, we are far from a comprehensive understanding of the molecular basis of this phenomenon. To(More)
Among the best-known examples of mutualistic symbioses is that between lower termites and the cellulolytic flagellate protists in their hindguts. Although the symbiosis in worker termites has attracted much attention, there have been only a few studies of protists in other castes. We have performed the first examination of protist population dynamics in(More)