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Miyagi University of Education, or MUE is a national university at Sendai, Miyagi, Japan. The predecessor of the school was founded in 1873, and it was chartered as a university in 1965. It is accredited by the Japanese Ministry of Education, as a public co-educational institute and is ranked in Japan's first tier of leading schools. With four academic divisions, MUE offers not only degrees in Education, but also in the disciplines of Language and Social Science, Science, Math and Life, and Art and Physical Education. Their Development and Education division covers Pre-School, Children and Culture, Pedagogy, and Educational Psychology. There are specific academic tracks for Elementary, Secondary, and Special Needs Education, and many of Miyagi University of Education’s graduates go on to become Principals at schools throughout Japan. Wikipedia.

Nakano T.,Tohoku University | Deguchi R.,Miyagi University of Education | Kyozuka K.,Tohoku University
Biochemical and Biophysical Research Communications | Year: 2014

Fertilization is such a universal and indispensable step in sexual reproduction, but a high degree of variability exists in the way it takes place in the animal kingdom. As discussed in other reviews in this issue, recent works on this subject clarified many points. However, important results on the mechanisms of fertilization are obtained mainly from a few restricted model organisms. In this sense, it is utterly important to collect more information from various phyla. In this review, we have re-introduced Annelida as one of the most suitable models for the analysis of fertilization process. We have briefly reviewed the historical works on the fertilization of Annelida. Then, we have described recent findings on the two independent Ca2+ increases in the fertilized eggs of Annelida, which arise from two different mechanisms and may have distinct physiological roles toward sperm entry and egg activation. We propose that the Ca2+ increase in the fertilized eggs reflect the specific needs of the zygote in a given species. © 2014 Elsevier Inc. All rights reserved.

Kashir J.,University of Oxford | Deguchi R.,Miyagi University of Education | Jones C.,University of Oxford | Coward K.,University of Oxford | Stricker S.A.,University of New Mexico
Molecular Reproduction and Development | Year: 2013

Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca2+) in all animals that have been examined, and such Ca2+ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca2+ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca2+ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca2+ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca2+ signals are typically propagated as global waves that depend on Ca2+ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP3). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca2+ transients are also examined. In addition, the importance of fertilization-induced Ca2+ signals for activating development is underscored by noting some major downstream effects of these signals in various animals. © 2013 Wiley Periodicals, Inc.

Munakata A.,Miyagi University of Education | Kobayashi M.,International Christian University
General and Comparative Endocrinology | Year: 2010

Sexual behavior is one of the most profound events during the life cycle of animals that reproduce sexually. After completion of gonadal development that is mediated by various hormones, oviparous teleosts perform a suite of behaviors, often termed as spawning behavior. This is particularly important for teleosts that have their gametes fertilized externally as the behavior patterns ensures the close proximity of both sexes for gamete release, fusion and ultimately the production of offspring. As in other vertebrates, sexual behavior of fish is also under the control of hormones. Testicular androgen is a requirement for male sexual behavior to occur in most fish species that have been studied. Unlike tetrapods, however, ovarian estrogen does not appear to be essential for the occurrence of female sexual behavior for fish that have their gametes fertilized externally. Prostaglandins produced in the ovary after ovulation act as a trigger in some teleosts to induce female sexual behavior. Potentiating effects of gonadotropin-releasing hormone in the brain on sexual behavior are reported in some species. Under endocrine regulation, male and female fish exhibit gender-typical behavior during spawning, but in some fish species there is also some plasticity in their sexual behavior. Sex changing fish can perform both male-typical and female-typical sexual behaviors during their lifetime and this sexual plasticity can also be observed in non-sex changing fish when undergoing hormonal treatment. Although the neuroanatomical basis is not clear in fish, results of field and laboratory observations suggest that some teleosts possess a sexually bipotential brain which can regulate two types of behaviors unlike most other vertebrates which have a discrete sex differentiation of their brain and can only perform gender-typical sexual behavior. © 2009 Elsevier Inc. All rights reserved.

Deguchi R.,Miyagi University of Education | Takeda N.,Tokyo Institute of Technology | Stricker S.A.,University of New Mexico
Molecular Reproduction and Development | Year: 2011

During maturation, oocytes must undergo a process of nuclear disassembly, or "germinal vesicle breakdown" (GVBD), that is regulated by signaling pathways involving cyclic AMP (cAMP). In vertebrate and starfish oocytes, cAMP elevation typically prevents GVBD. Alternatively, increased concentrations of intra-oocytic cAMP trigger, rather than inhibit, GVBD in several groups of marine invertebrates. To integrate what is known about the stimulation of GVBD by intra-oocytic cAMP, this article reviews published data for ascidian, bivalve, brittle star, jellyfish, and nemertean oocytes. The bulk of the review concentrates on the three most intensively analyzed groups known to display cAMP-induced GVBD-nemerteans, ascidians, and jellyfish. In addition, this synopsis also presents some previously unpublished findings regarding the stimulatory effects of intra-oocytic cAMP on GVBD in jellyfish and the annelid worm Pseudopotamilla occelata. Finally, factors that may account for the currently known distribution of cAMP-induced GVBD across animal groups are discussed. © 2011 Wiley Periodicals, Inc.

Koizumi Y.,Tohoku University | Hara Y.,Tohoku University | Yazaki Y.,Japan National Institute of Agrobiological Science | Sakano K.,Japan National Institute of Agrobiological Science | Ishizawa K.,Miyagi University of Education
New Phytologist | Year: 2011

Pondweed (Potamogeton distinctus) turions can elongate in the absence of O2. Alcoholic fermentation serves to produce energy for anoxic elongation via the breakdown of starch stored in cells. However, the mechanism of cell growth during anoxic elongation is not fully understood. Changes in pH, H+ equivalent and lactate content of the incubation medium were measured during anoxic elongation. The effects of fusicoccin (FC), indole-3-acetic acid (IAA), vanadate, erythrosine B and K+ channel blockers on anoxic elongation were examined. Cytoplasmic pH and vacuolar pH were measured by 31P nuclear magnetic resonance (NMR) spectroscopy. Acidification of the incubation medium occurred during anoxic elongation. The contribution of CO2 and lactic acid was not sufficient to explain the acidification. FC and IAA enhanced the elongation of stem segments. Vanadate and erythrosine B inhibited anoxic elongation. Acid growth of notched segments was observed. The activity of plasma membrane H+-ATPase extracted from pondweed turions was increased slightly in anoxic conditions, but that from pea epicotyls sensitive to anoxic conditions was decreased by incubation in anoxic conditions. Both the cytoplasmic pH and vacuolar pH of pondweed turion cells chased by 32P NMR spectroscopy were stabilized during a short period <3h after anoxic conditions. We propose that the enhancement of H+ extrusion by anoxic conditions induces acidification in the apoplast and may contribute to the stabilization of pH in the cytoplasm. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

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