60 research outputs found

    Developmental Link between Sex and Nutrition; \u3ci\u3edoublesex\u3c/i\u3e Regulates Sex-Specific Mandible Growth via Juvenile Hormone Signaling in Stag Beetles

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    Sexual dimorphisms in trait expression are widespread among animals and are especially pronounced in ornaments and weapons of sexual selection, which can attain exaggerated sizes. Expression of exaggerated traits is usually male-specific and nutrition sensitive. Consequently, the developmental mechanisms generating sexually dimorphic growth and nutritiondependent phenotypic plasticity are each likely to regulate the expression of extreme structures. Yet we know little about how either of these mechanisms work, much less how they might interact with each other. We investigated the developmental mechanisms of sex-specific mandible growth in the stag beetle Cyclommatus metallifer, focusing on doublesex gene function and its interaction with juvenile hormone (JH) signaling. doublesex genes encode transcription factors that orchestrate male and female specific trait development, and JH acts as a mediator between nutrition and mandible growth. We found that the Cmdsx gene regulates sex differentiation in the stag beetle. Knockdown of Cmdsx by RNA-interference in both males and females produced intersex phenotypes, indicating a role for Cmdsx in sex-specific trait growth. By combining knockdown of Cmdsx with JH treatment, we showed that female-specific splice variants of Cmdsx contribute to the insensitivity of female mandibles to JH: knockdown of Cmdsx reversed this pattern, so that mandibles in knockdown females were stimulated to grow by JH treatment. In contrast, mandibles in knockdown males retained some sensitivity to JH, though mandibles in these individuals did not attain the full sizes of wild type males. We suggest that moderate JH sensitivity of mandibular cells may be the default developmental state for both sexes, with sex-specific Dsx protein decreasing sensitivity in females, and increasing it in males. This study is the first to demonstrate a causal link between the sex determination and JH signaling pathways, which clearly interact to determine the developmental fates and final sizes of nutrition-dependent secondary-sexual characters

    Developing the Kandai style Experiential Learning Program (K-ELP) : From Practical Knowledge to Inquiring a way of living

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    In this article, the development of the Kandai style ExperientialLearning Program(K-ELP) is described with its background issues, thehistory of its development, and the program constitution. For the pastten years, various criticism towards Japanese higher education,especially its separation from the social needs of educating wellfunctioningstudents in the society, has been increasing. Respondingto this crticism, active learning and cooperative learning have beenbrought into Japanese higher education, but it often remains as merechange of class management without deeper pedagogical transformation.With this analysis, we developed a systematic learning program basedon Dewey’s experiential learning philosophy, which we named Kandaistyle Experiential Learning Program (K-ELP). K-ELP is constituted offour parts, ① Experiential Learning Program, ② Expert Level-upProgram, ③Experimental Life-world Projects, and ④Experiencing LifeProcess. Students go through these four parts step-by-step, startingwith their first year program and contiuning onto various projectsduring seminar activities.本稿は、平成25年-平成27年度関西大学教育研究高度化促進費において課題「プロジェクトアドベンチャーを基盤にした体験教育型研修プログラム開発」として助成を受けた成果を公表するものである。このPDFデータは、著者版であるため、出版社版とはページ数が異なっています

    P301S Mutant Human Tau Transgenic Mice Manifest Early Symptoms of Human Tauopathies with Dementia and Altered Sensorimotor Gating

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    Tauopathies are neurodegenerative disorders characterized by the accumulation of abnormal tau protein leading to cognitive and/or motor dysfunction. To understand the relationship between tau pathology and behavioral impairments, we comprehensively assessed behavioral abnormalities in a mouse tauopathy model expressing the human P301S mutant tau protein in the early stage of disease to detect its initial neurological manifestations. Behavioral abnormalities, shown by open field test, elevated plus-maze test, hot plate test, Y-maze test, Barnes maze test, Morris water maze test, and/or contextual fear conditioning test, recapitulated the neurological deficits of human tauopathies with dementia. Furthermore, we discovered that prepulse inhibition (PPI), a marker of sensorimotor gating, was enhanced in these animals concomitantly with initial neuropathological changes in associated brain regions. This finding provides evidence that our tauopathy mouse model displays neurofunctional abnormalities in prodromal stages of disease, since enhancement of PPI is characteristic of amnestic mild cognitive impairment, a transitional stage between normal aging and dementia such as Alzheimer's disease (AD), in contrast with attenuated PPI in AD patients. Therefore, assessment of sensorimotor gating could be used to detect the earliest manifestations of tauopathies exemplified by prodromal AD, in which abnormal tau protein may play critical roles in the onset of neuronal dysfunctions
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