Reciprocal activation within a kinase effector complex: A mechanism for the persistence of molecular memory

Synaptic connections in neuronal circuits change in response to neuronal activity patterns. This can induce a persistent change in the efficacy of synaptic transmission, a phenomenon known as synaptic plasticity. One form of plasticity, long-term potentiation (LTP) has been extensively studied as the cellular basis of memory. In LTP, the potentiated synaptic transmission persists along with structural changes in the synapses. Many studies have sought to identify the "memory molecule" or the "molecular engram". Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) is probably the most well-studied candidate for the memory molecule. However, consensus has not yet been reached on a very basic aspect: how CaMKII is regulated during LTP. Here, I propose a new model of CaMKII regulation: reciprocal activation within a kinase effector complex (RAKEC) that is made between CaMKII and its effector protein, which is mediated by a persistent interaction between CaMKII and a pseudosubstrate sequence on T-lymphoma invasion and metastasis protein 1 (Tiam1), resulting in reciprocal activation of these two molecules. Through the RAKEC mechanism, CaMKII can maintain memory as biochemical activity in a synapse-specific manner. In this review, the detailed mechanism of the RAKEC and its expansion for the maintenance of LTP is described

Molecular cloning and expression profile of Xenopus calcineurin A subunit11The nucleotide sequence of XCnA has been deposited in DDBJ/DMBL/GenBank DNA database under the accession number AB037146.

AbstractWe have cloned a cDNA encoding a catalytic subunit of calcineurin (CnA) expressed in Xenopus oocytes. The deduced amino acid sequence indicates 96.3% and 96.8% identities with the mouse and human CnAα isoforms, respectively. Xenopus CnA (XCnA) RNA and protein are expressed as maternal and throughout development. Recombinant XCnA protein interacted with calmodulin in the presence of Ca2+. Deletion of calmodulin binding domain and auto-inhibitory domain revealed calcium independent phosphatase activity, thereby showing that XCnA is likely to be modulated by both calmodulin and calcium

Oscillation threshold of a clarinet model: a numerical continuation approach

This paper focuses on the oscillation threshold of single reed instruments. Several characteristics such as blowing pressure at threshold, regime selection, and playing frequency are known to change radically when taking into account the reed dynamics and the flow induced by the reed motion. Previous works have shown interesting tendencies, using analytical expressions with simplified models. In the present study, a more elaborated physical model is considered. The influence of several parameters, depending on the reed properties, the design of the instrument or the control operated by the player, are studied. Previous results on the influence of the reed resonance frequency are confirmed. New results concerning the simultaneous influence of two model parameters on oscillation threshold, regime selection and playing frequency are presented and discussed. The authors use a numerical continuation approach. Numerical continuation consists in following a given solution of a set of equations when a parameter varies. Considering the instrument as a dynamical system, the oscillation threshold problem is formulated as a path following of Hopf bifurcations, generalizing the usual approach of the characteristic equation, as used in previous works. The proposed numerical approach proves to be useful for the study of musical instruments. It is complementary to analytical analysis and direct time-domain or frequency-domain simulations since it allows to derive information that is hardly reachable through simulation, without the approximations needed for analytical approach

Support Systems for Instructors and Teaching Assistants in the ALESS Program

Teaching English communication to students of science is an essential aspect of scientific education, if students are to develop and become competitive in a global setting. The ALESS (Active Learning of English for Science Students) Program at the University of Tokyo is a 13-week academic writing course for all first-year students of science. The course is taught completely in English by instructors with diverse backgrounds from not just the natural sciences, but also from the social sciences and humanities. For this course, active learning is encouraged and the scientific thought process is emphasized through project-based learning, and students partake in this scientific process by designing and performing scientific experiments which provides the content for their academic papers. Here, the “support system” includes assistance for students as well as mutual cooperation amongst instructors. As instructors have diverse academic and teaching backgrounds, collaboration and mutual learning constitute an important element of the development of effective curriculum and pedagogy. Among various aspects of the ALESS course, this paper specifically focuses on the supporting system involved in the course. Based on the close examination of the current situation, this paper proposes some possible solutions to problems observed in this study. This study may contribute to the development of course design and teaching methods in English for Specific Academic Purposes. In this paper, reasons for students to seek advice will be discussed with specific examples of some actual visits. Furthermore, recent attempts to minimize the gap between students’ interests and TAs’ background disciplines to provide more effective consultations will be mentioned. Some reflections by instructors of various backgrounds as well as some specific concerns that have risen will be reported. Here, we will consider some of the difficulties that are encountered, not by students, but by the instructors and teaching assistants who directly support those taking the course, and discuss the support systems that are in place.Section 2: Pedagogic-Methodological Practice

Interaction of reed and acoustic resonator in clarinetlike systems

Sound emergence in clarinetlike instruments is investigated in terms of instability of the static regime. Various models of reed-bore coupling are considered, from the pioneering work of Wilson and Beavers ["Operating modes of the clarinet", J. Acoust. Soc. Am. 56, 653--658 (1974)] to more recent modeling including viscothermal bore losses and vena contracta at the reed inlet. The pressure threshold above which these models may oscillate as well as the frequency of oscillation at threshold are calculated. In addition to Wilson and Beavers' previous conclusions concerning the role of the reed damping in the selection of the register the instrument will play on, the influence of the reed motion induced flow is also emphasized, particularly its effect on playing frequencies, contributing to reduce discrepancies between Wilson and Beavers' experimental results and theory, despite discrepancies still remain concerning the pressure threshold. Finally, analytical approximations of the oscillating solution based on Fourier series expansion are obtained in the vicinity of the threshold of oscillation. This allows to emphasize the conditions which determine the nature of the bifurcation (direct or inverse) through which the note may emerge, with therefore important consequences on the musical playing performances

S・O・ジュウェットノ作品ニオケル女性ノ友情 : 『トンガリ樫ノ木ノ国』

本稿は、サラ・オーン・ジュウェットの作品における女性の友情パターンと性質を研究する一連の試みの第二稿である。第一稿では作者の初期の作品であるDeephavenを扱ったが、本稿では後期の作品で最高の傑作とされているThe Country of the Pointed Firsを扱うこととする。女性の友情に関する枠組み設定はすでに第一稿でなされており、それに照らしてどのような相違があるかを明らかにする。この二つの作品は、約二十年の時を隔てて出版されたが、作品の構成、場面設定、登場人物、および主題など多くの共通点を有するものである。にもかかわらず、女性の友情という視点から見ると、二作品には大きな乖離がある。すなわち、若い女性の感傷的な友情と成熟した大人の女性の社会性を帯びた友情である。この乖離は作者自身の二十年間の実体験に帰することができると考えられる。したがって、次稿はジュウェット自身の女性たちとの友情について検証する。This paper is the second in a series which aims to explore the pattern and nature of women\u27s friendship as described in the works of Sarah Orne Jewett. The first paper introduced five categories of friendship as proposed by Janet Todd ; namely sentimental, erotic, manipulative, political and social. By so doing, it has established the framework of women\u27s friendship for the following discussions of Jewett\u27s individual works. It also analysed one of her early works, Deephaven, in contrast to this paper which will discuss Jewett\u27s later work, The Country of the Pointed Firs, her acknowledged masterpiece. Section I examines The Country of the Pointed Firs in general terms and then more specifically from the perspective of female friendship. In Section II a comparison between Deephaven and The Country of the Pointed Firs is made in terms of structure, themes, characters as well as Jewett\u27s artistic skills. In addition, another comparison is examined in regard to the pattern and nature of women\u27s friendship in the two works

Evolution of the Genus Camellia Based on the Biological Interaction and the Historical Background

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