交尾依存的な生殖幹細胞増殖を制御する神経内分泌機構の追究

筑波大学 (University of Tsukuba)201

交尾依存的な生殖幹細胞増殖を制御する神経内分泌機構の追究

この博士論文は内容の要約のみの公開（または一部非公開）になっています筑波大学 (University of Tsukuba)201

Perturbed Stress Field of the Human Lens Capsule After Cataract Surgery

Current modeling of the human lens capsule has been focused on the mechanism of accommodation and its decline with age, but few studies have modeled the effects of cataract surgery and quantified the altered mechanical environment introduced by the procedure. The goal of this study is to develop the first fully 3-D finite element model of the post-surgical human lens capsule with an implanted device in order to characterize lens capsule mechanics after cataract surgery. The model demonstrates a highly perturbed stress field compared to the native state, which we hypothesize is the primary driving force behind the long-term errant cell behavior that causes secondary cataracts. Such predict capabilities may lend insight on future intraocular lens designs, potentially ones that can restore youthful accommodation

Food, microbes, sex and old age: on the plasticity of gastrointestinal innervation

The gastrointestinal tract is innervated by its own enteric nervous system and by extrinsic neurons that connect it with the central nervous system. Innervation allows the gastrointestinal tract to sense and respond to diverse stimuli, adjusting motility and secretion, but also affecting our physiology, behaviour and immunity. The mechanisms underlying the formation of gastrointestinal neurons are beginning to be elucidated; those that keep them plastic over an organism's lifetime remain to be explored. Here, we review the effects of microbiota, nutrients, sex and ageing on the morphology and function of gastrointestinal innervation in mammals, and discuss how this plasticity shapes gut-brain crosstalk and whole-body physiology. We also highlight insights gained by nascent studies of the enteric innervation of Drosophila melanogaster

Implantation of a capsular tension ring during cataract surgery attenuates predicted remodeling of the post-surgical lens capsule along the visual axis

Introduction: Cataract surgery permanently alters the mechanical environment of the lens capsule by placing a hole in the anterior portion and implanting an intraocular lens (IOL) that has a very different geometry from the native lens. We hypothesized that implant configuration and mechanical interactions with the post-surgical lens capsule play a key role in determining long-term fibrotic remodeling. Methods: We developed the first finite element-growth and remodeling (FE-G&R) model of the post-surgical lens capsule to evaluate how implantation of an IOL with and without a capsular tension ring (CTR) impacted evolving lens capsule mechanics and associated fibrosis over time after cataract surgery. Results: Our models predicted that implantation of a CTR with the IOL into the post-surgical lens capsule reduced the mechanical perturbation, thickening, and stiffening along the visual axis in both the remnant anterior and posterior portions compared to implantation of the IOL alone. Discussion: These findings align with patient studies and suggest that implantation of a CTR with the IOL during routine cataract surgery would attenuate the incidence of visually-debilitating capsule fibrosis. Our work demonstrates that use of such modeling techniques has substantial potential to aid in the design of better surgical strategies and implants

Endocrine regulation of female germline stem cells in the fruit fly Drosophila melanogaster

Germline stem cells (GSCs) are critical for the generation of sperms and eggs in most animals including the fruit fly Drosophila melanogaster. It is well known that self-renewal and differentiation of female D. melanogaster GSCs are regulated by local niche signals. However, little is known about whether and how the GSC number is regulated by paracrine signals. In the last decade, however, multiple humoral factors, including insulin and ecdysteroids, have been recognized as key regulators of female D. melanogaster GSCs. This review paper summarizes the role of humoral factors in female D. melanogaster GSC proliferation and maintenance in response to internal and external conditions, such as nutrients, mating stimuli, and aging

Ovarian ecdysteroid biosynthesis and female germline stem cells

The germline stem cells (GSCs) are critical for gametogenesis throughout the adult life. Stem cell identity is maintained by local signals from a specialized microenvironment called the niche. However, it is unclear how systemic signals regulate stem cell activity in response to environmental cues. In our previous article, we reported that mating stimulates GSC proliferation in female Drosophila. The mating-induced GSC proliferation is mediated by ovarian ecdysteroids, whose biosynthesis is positively controlled by Sex peptide signaling. Here, we characterized the post-eclosion and post-mating expression pattern of the genes encoding the ecdysteroidogenic enzymes in the ovary. We further investigated the biosynthetic functions of the ovarian ecdysteroid in GSC maintenance in the mated females. We also briefly discuss the regulation of the ecdysteroidogenic enzyme-encoding genes and the subsequent ecdysteroid biosynthesis in the ovary of the adult Drosophila

A transição agroecológica: desafios para a agricultura sustentável

O desafio de alimentar a população crescente e ao mesmo tempo conservar os recursos naturais é uma problemática ambiental contemporânea, visto que a forma moderna hegemônica altamente industrializada tem causado prejuízos aos ecossistemas e à saúde humana. O objetivo do presente trabalho é realizar um estudo bibliográfico sobre os marcos legais da agricultura alternativa e analisar os obstáculos da transição agroecológica em alcançar o tripé do desenvolvimento socialmente justo, economicamente viável e ambientalmente correto. Embora exista diferentes visões e correntes filosóficas da agroecologia, a legislação brasileira a equipara com a agricultura orgânica e traz o entendimento da transição agroecológica como um processo gradual de mudança de práticas e de manejo de base ecológica. A agricultura quando praticada segundo os princípios da agroecologia tem o potencial de transformar as realidades rurais, aportar a segurança alimentar e nutricional, além de manter a fertilidade do solo. O desafio da agricultura sustentável é a superação dos custos iniciais da conversão dos agroecossistemas e o acesso sistemático à assistência técnica capacitada. Estas limitações podem ser enfrentadas com a articulação de redes de apoio entre produtores ecológicos e consumidores reflexivos que promove o espaço de diálogo de saberes e a politização do consumo alimentar. A utilização de ferramentas de avaliação do nível de transição agroecológica pode auxiliar no reconhecimento das oportunidades, nas adequações normativas e no desenvolvimento de tecnologias sociais que vão de encontro a alguns dos Objetivos de Desenvolvimento Sustentável

PERFIL DA PRODUÇÃO ORGÂNICA NO ESTADO DE MINAS GERAIS E AS NOVAS RELAÇÕES ENTRE PRODUÇÃO E CONSUMO DE ALIMENTOS

The objective of this work was to identify the profile of organic production in the state of Minas Gerais and the new relationships established between ecological producers and reflective consumers. Through documentary research of the national register of organic production, a quantitative analysis of the geographical distribution, the conformity assessment mechanisms adopted and the productive diversity was carried out. From the 12 mesoregions of the state defined by IBGE, it was verified that the south and southwest mesoregion of Minas Gerais has the largest number of agricultural units and great diversity of registered items. Together, the Participatory Conformity Assessment Body (OPAC) and the Social Control Organization (OCS) are responsible for 43% of organic compliance assessments, while audit certifications prevail. Two case studies are presented that highlight the differential of participatory organizations and point out new relationships between food production and consumption. The articulation in transparent networks generates trust between producers and consumers, guarantees traceability and participatory socio-environmental management since it brings the protagonists closer together, shortens supply circuits and invites reflection on eating behavior, environmental conservation and improvement of soil and plant health people.El objetivo del trabajo fue identificar el perfil de la producción orgánica en el estado de Minas Gerais y las nuevas relaciones que se establecen entre productores ecológicos y consumidores reflexivos. A través de la investigación documental del registro nacional de producción orgánica, se realizó un análisis cuantitativo de la distribución geográfica, los mecanismos de evaluación de la conformidad adoptados y la diversidad productiva. De las 12 mesorregiones definidas por el IBGE, se verificó que la mesorregión sur y suroeste de Minas Gerais tiene mayor número de unidades agrícolas y gran diversidad de productos registrados. Juntos, el Organismo de Evaluación Participativa de la Conformidad (OPAC) y el Organismo de Control Social (OCS) representan 43% de las evaluaciones de cumplimiento orgánico, mientras que las certificaciones de auditoría prevalecen. Se presentan dos estudios de caso que destacan el diferencial de las organizaciones participativas y señalan nuevas relaciones entre la producción y el consumo de alimentos. La articulación en redes transparentes genera confianza entre productores y consumidores, garantiza trazabilidad y gestión socioambiental participativa ya que acerca los protagonistas, acorta circuitos de abastecimiento e invita a la reflexión sobre las conductas alimentarias, la conservación del medio ambiente y mejora de la salud de los suelos y las personas.O objetivo do trabalho foi identificar o perfil da produção orgânica do estado de Minas Gerais e as novas relações estabelecidas entre os produtores ecológicos e os consumidores reflexivos. Por meio da pesquisa documental do cadastro nacional de produção orgânica foi feita uma análise quantitativa da distribuição geográfica, dos mecanismos de avaliação da conformidade adotado e da diversidade produtiva. A partir das 12 mesorregiões do estado estabelecidas pelo IBGE, verificou-se que a mesorregião sul e sudoeste de Minas Gerais apresenta o maior número de unidades agrícolas e grande diversidade de itens cadastrados. Juntos, o Organismo Participativo de Avaliação da Conformidade (OPAC) e a Organização de Controle Social (OCS) são responsáveis por 43% das avaliações da conformidade orgânica, enquanto que as certificações por auditoria prevalecem. São apresentados dois estudos de caso que destacam o diferencial dos organismos participativos e apontam novas relações entre produção e consumo de alimentos. A articulação em redes transparentes gera confiança entre produtores e consumidores, garante rastreabilidade e gestão socioambiental participativa uma vez que aproxima os protagonistas, encurta os circuitos de abastecimento e convida a refletir sobre o comportamento alimentar, a conservação ambiental e melhoria da saúde do solo e das pessoas

Implantation of a capsular tension ring during cataract surgery attenuates predicted remodeling of the post-surgical lens capsule along the visual axis

Introduction: Cataract surgery permanently alters the mechanical environment of the lens capsule by placing a hole in the anterior portion and implanting an intraocular lens (IOL) that has a very different geometry from the native lens. We hypothesized that implant configuration and mechanical interactions with the post-surgical lens capsule play a key role in determining long-term fibrotic remodeling.Methods: We developed the first finite element-growth and remodeling (FE-G&R) model of the post-surgical lens capsule to evaluate how implantation of an IOL with and without a capsular tension ring (CTR) impacted evolving lens capsule mechanics and associated fibrosis over time after cataract surgery.Results: Our models predicted that implantation of a CTR with the IOL into the post-surgical lens capsule reduced the mechanical perturbation, thickening, and stiffening along the visual axis in both the remnant anterior and posterior portions compared to implantation of the IOL alone.Discussion: These findings align with patient studies and suggest that implantation of a CTR with the IOL during routine cataract surgery would attenuate the incidence of visually-debilitating capsule fibrosis. Our work demonstrates that use of such modeling techniques has substantial potential to aid in the design of better surgical strategies and implants