Advances in the Regulation of Follicular Development by Extracellular Vesicles and Non-Coding RNAs / 中国医学科学院学报

Extracellular vesicles (EV),nanoscale vesicles encapsulated by phospholipid bilayers,are rich in biological molecules such as nucleic acids,metabolites,proteins,and lipids derived from parental cells.They are mainly involved in intercellular communication,signal transmission,and material transport and affect the functions of target cells.Ovulation disorders account for a higher proportion in the factors causing infertility which demonstrates increasing incidence year by year.Non-coding RNAs participate in a series of physiological and pathological processes of follicular development,playing a key role in female infertility.This review systematically introduces the types and biological roles of EV and elaborates on the regulation of follicular development from the effects of EV and non-coding RNAs on granulosa cell function,oocyte maturation,ovulation,luteal formation,and steroid hormone synthesis,providing a new idea and a breakthrough point for the diagnosis and treatment of infertility.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae) / Caracterização gonadal do peixe Amazônico Serrapinnus kriegi (Characidae: Cheirodontinae)

The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters’ turbulence that characterize it spawning sites in the Amazonian streams. The male specimens’ present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae) / Caracterização gonadal do peixe Amazônico Serrapinnus kriegi (Characidae: Cheirodontinae)

Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.

New Insights into the Gametogenesis of Biomphalaria glabrata (Mollusca, Gastropoda, Pulmonata): Implications for Histopathological Assessment

Abstract The reproductive system has a fundamental role in population dynamics and several reproduction strategies have been shaped by the environment over time. Many environmental pressures are generated by releasing pollutants, as endocrine disruptors, that can affect the reproductive system of individuals, among them invertebrates. The freshwater snails Biomphalaria spp. are used as biomonitor in several ecotoxicological studies; however, there are few studies about gametogenesis and morphology of reproductive snail cells, which could be used as a new biomarker. In this sense, the current study aims to characterize Biomphalaria glabrata gametogenesis, bringing new histomorphometric parameters for germinative cells. Results showed that the hermaphrodite tissue is formed by several acini with simple pavement epithelium with germinative and somatic cells. Oogenesis was classified into five developmental stages (OI to OV) according to diameter, nucleus area, total area, and follicular cell development, and then classified into previtellogenic and vitellogenic oocytes. The spermatogenesis was classified into spermatogonia (Spg), spermatocytes (Spc) and spermatids that were subdivided into five stages (Spt I to Spt V) according to cytoplasm losing, and nucleus spiralization along with Sertoli cells development. Thus, the present study highlights the gametogenesis of B. glabrata with new histomorphometric parameters, which can be an important tool for ecotoxicological and molluscicidal developmental further studies.

The role of histone deacetylases 1/2 in regulating murine oogenesis / 生理学报

Oogenesis is the basic reproductive process of female mammals and is essential for fertilization and embryo development. Recent studies have shown that epigenetic modifications play an important role in the regulation of mammalian reproductive processes (such as oogenesis, spermatogenesis, preimplantation embryo development and sex differentiation). Taking histone acetylation as an instance, the dynamic changes of histone acetyltransferases (HATs) and deacetylases (HDACs) are involved in the regulation of gene activation and inactivation when numerous key physiological events occur during reproduction. Thereinto, HDAC1 and HDAC2, which are highly homologous in terms of both structure and function, play a pivotal role in murine oogenesis. HDAC1 and 2 jointly regulate the global transcription and the incidence of apoptosis of growing oocytes and affect its subsequent growth and development, which reflects their compensatory function. In addition, HDAC1 and 2 also play a specific part in oogenesis respectively. It has shown that HDAC2 is more critical than HDAC1 for oocyte development, which regulates de novo DNA methylation and chromosome segregation. Reciprocally, HDAC1 is more critical than HDAC2 for preimplantation development. Deficiency of HDAC1 causes the decreased proliferation of embryonic stem cells and the smaller embryoid bodies with irregular shape. In this review, we summarized the role and the current research progress of HDAC1/2 in murine oogenesis, to provide a reference for further understanding the relationship between epigenetic modifications and reproductive regulation.

Research progress of cyclic adenosine monophosphate in mammalian follicular development / 生理学报

Cyclic adenosine monophosphate (cAMP) is one of the significant and conserved second messengers in mammals, and it participates in regulating the developmental and physiological functions of various organs and tissues through transducting extracellular signals. Studies have shown that the process of meiosis in female mammalian oocytes is closely related to the level of cAMP and strictly regulated. In oocytes, cAMP is mainly synthesized by adenylate cyclase 3 (AC3) and degraded by phosphodiesterase 3A (PDE3A), both of which jointly regulate the level of cAMP in oocytes and play important roles in the follicular development and oogenesis of female ovaries. It has been well illuminated that high level of cAMP in the cytoplasm of oocytes in growing follicles could maintain the arrest of the first meiotic of oocytes for a long time. The oocytes will resume meiosis and mature either when the synthesis of cAMP is down-regulated, or when cAMP is degraded by PDE3A. In recent years, the novo physiological functions of cAMP in oogenesis have been reported. To better understand the regulatory role and mechanism of cAMP in mammalian gametogenesis, this paper reviews the relevant research regarding the relationship between cAMP and germ cell development.

Advances of the Regulation of microRNAs in Follicular Development / 中国医学科学院学报

In recent years,microRNAs(miRNAs)have been detected at different stages of follicular development and in different cells of follicles.Extracellular vesicle(EV)-derived miRNAs have also been detected in the follicular fluid of mature follicles.miRNAs participate in the regulation of normal follicular development,and the regulation disorder may lead to the occurrence of some ovarian diseases.In order to further systematically elucidate the regulatory mechanism of miRNAs on follicular development and find suitable EV-derived miRNAs that can predict oocyte development,we reviewed the functions of miRNAs in follicular development from the perspectives of granulosa cell development,oocyte development,and hormone synthesis.

Advances in research on the development of female germ cells / 中华医学遗传学杂志

The development of female germ cells can be mainly divided into two stages: fetal germ cells and oocytes in folliculogenesis after puberty. Mitosis-meiosis transition, meiosis arrest and re-activation are the key phases of the development. Several phases may be characterized by their distinct molecular events, which involve precise regulation of gene expression and interaction with corresponding gonadal niche cells. In recent years, single-cell transcriptome studies have clarified phase-specific patterns of gene expression, signaling pathways and epigenetic modification during oogenesis and folliculogenesis. These works have provided important insights into the development of female germ cells and pathogenesis of germ-cell related diseases, which may promote clinical application of reproductive genetic research.

Effect of extracellular vesicles and microRNAs in follicular fluid on follicular development / 生物工程学报

Extracellular vesicles (EVs) refer to bilayer membrane transport vesicles secreted by cells. EVs can take macromolecules from cells and transfer them to receptor cells. Among these macromolecular substances, the most studied are microRNAs (miRNAs). miRNA is non-coding RNA involved in the regulation of gene expression. It has been confirmed that there are different non-coding RNAs in mammalian follicular fluid EVs. EVs carrying miRNA can act as an alternative mechanism for autocrine and paracrine, affecting follicular development. This paper systematically introduced the kinds, characteristics and methods of isolation and identification of EVs, focusing on the effects of EVs and miRNAs on follicular development, including early follicular development, oocyte maturation, follicular dominance and effects on granulosa cell function. At the same time, the authors prospected the future research of EVs and microRNAs in follicular fluid, and provided ideas and directions for the research and application of EVs and miRNA functions in follicular fluid.

Poorly-Controlled Type 1 Diabetes Mellitus Impairs LH-LHCGR Signaling in the Ovaries and Decreases Female Fertility in Mice

PURPOSE: The aim of this study was to investigate how type I diabetes mellitus (T1D) affects the folliculogenesis and oocyte development, fertilization, and embryo development. MATERIALS AND METHODS: A comparative animal study was conducted using two different mouse models of T1D, a genetic AKITA model and a streptozotocin-induced diabetes model. Ovarian function was assessed by gross observation, immunoblot, immunohistochemistry, oocyte counting, and ELISA for serum hormones (insulin, anti-Mullerian hormone, estradiol, testosterone, and progesterone). Maturation and developmental competence of metaphase II oocytes from control and T1D animals was evaluated by immunofluorescent and immunohistochemical detection of biomarkers and in vitro fertilization. RESULTS: Animals from both T1D models showed increased blood glucose levels, while only streptozotocin (STZ)-injected mice showed reduced body weight. Folliculogenesis, oogenesis, and preimplantation embryogenesis were impaired in both T1D mouse models. Interestingly, exogenous streptozotocin injection to induce T1D led to marked decreases in ovary size, expression of luteinizing hormone/chorionic gonadotropin receptor in the ovaries, the number of corpora lutea per ovary, oocyte maturation, and serum progesterone levels. Both T1D models exhibited significantly reduced pre-implantation embryo quality compared with controls. There was no significant difference in embryo quality between STZ-injected and AKITA diabetic mice. CONCLUSION: These results suggest that T1D affects folliculogenesis, oogenesis, and embryo development in mice. However, the physiological mechanisms underlying the observed reproductive effects of diabetes need to be further investigated.

Imunolocalização de receptores de leptina no ovário de preás (Galea spixii Wagler, 1831) / Immunolocalization of leptin receptor of Spix's Yellow-toothed Cavy (Galea spixii Wagler, 1831) ovary

A leptina, uma citocina produzida pelas células adiposas, é alvo da comunidade científica por acreditarem que ela apresente impacto sobre a reprodução dos animais promovendo a puberdade, foliculogênese e oogênese, ciclo estral e auxiliando na fecundação. A compreensão dos mecanismos que controlam a atividade reprodutiva de preás (Galea spixii) possui papel relevante para a preservação da espécie. Desta forma, o presente trabalho propôs analisar a imunolocalização dos receptores de leptina (Ob-R) no ovário de preás. Coletaram-se os ovários de 20 fêmeas adultas, não prenhes e saudáveis. As amostras foram fixadas em paraformaldeído a 4% em tampão fosfato, incluídas em parafina e seccionadas para a realização de imunohistoquímica (IHC). As secções foram fotomicrografadas e avaliadas quanto à intensidade da reação. Observou-se forte imunorreação no oócito e nas células da teca, moderada nas células do estroma ovariano e nas células luteínicas grandes e fracamente coradas nas células da granulosa, endoteliais, perivasculares e células luteínicas pequenas. Quando comparado a expressão de receptores ao longo do desenvolvimento folicular foi observado que o oócito e as células da teca se mantiveram com expressão na mesma intensidade. Entretanto, as células da granulosa apresentaram forte marcação nos estádios pré-antrais enquanto que nos folículos antrais apresentou fraca intensidade. Concluímos que em ovários de Galea spixii existe a presença de Ob-R nas principais estruturas do ovário sugerindo que este hormônio desempenhe papel fundamental na reprodução desta espécie.

Leptin, a cytokine produced by adipose cells, is the target of the scientific community for believing that it has an impact on the reproduction of the animals promoting puberty, folliculogenesis and oogenesis, estrous cycle and aiding in fertilization. The understanding of the mechanisms controlling the reproductive activity of Spix's Yellow-toothed Cavy (Galea spixii) plays a relevant role in the preservation of the species. Thus, the present study proposed to analyze the immunolocalization of leptin receptors (Ob-R) in the ovary of cavies. Ovaries from 20 adult, non-pregnant, healthy females were collected. The samples were fixed in 4% phosphate buffered paraformaldehyde, embedded in paraffin and sectioned for immunohistochemistry. The sections were photomicrographs and intensity of the reaction was measured. Strong immunoreaction was observed in oocyte and theca cells, moderate in ovarian stromal cells and large luteal cells and weak stained in granulosa, endothelial, perivascular and small luteal cells. When compared to receptor expression along follicular development it was observed that the oocyte and the theca cells remained with expression at the same intensity. However, the granulosa cells presented strong stained in the preantral stages, whereas in the antral follicles it presented low intensity. We conclude that in the ovaries of Galea spixii there is the presence of Ob-R in the main structures of the ovary sugesting that this hormone plays a fundamental role in the reproduction of this species.

Ovarian histology and fecundity in the evaluation of the reproduction of the invasive species Serrasalmus marginatus (Characidae) on a neotropical floodplain / Histologia ovariana e fecundidade na avaliação da reprodução da espécie invasora Serrasalmus marginatus (Characidae) em uma planície de inundação neotropical

The construction of the Itaipu Hydroelectric Power Plant in 1982 led to the formation of a reservoir, which, in turn, leveled the waters of the Paraná River by flooding the geographic barrier Salto de Sete Quedas. This allowed the piranha Serrasalmus marginatus to invade and colonize the upper Paraná River. This study aimed to: i) confirm, through light microscopy, the reproductive phases of S. marginatus females; ii) estimate fecundity and iii) evaluate the reproduction areas of the population. A total of 764 females were collected from nine sampling sites on the upper Paraná River floodplain. Microscopic analysis of the ovaries showed the following phases: early developing subphase, developing phase, spawning capable phase, actively spawning subphase, regressing phase and regenerating phase. The frequency distribution of the oocytes shows that spawning is fractional and fecundity indeterminate. Fecundity varied from 410 to 752 oocytes (mean = 584). The continual spawning of oocytes during the long reproductive period, as well as the aggressiveness of the species as regards the defense of its offspring, guarantees more descendants in the Patos, Ventura, Fechada, Guaraná and Garças lagoons and Ivinheima and Baia rivers of the upper Paraná River floodplain.

A construção da Usina Hidroelétrica de Itaipu, em 1982, levou a formação do reservatório que por sua vez nivelou as águas do rio Paraná inundando a barreira geográfica do salto de Sete Quedas. Isto permitiu que a piranha Serrasalmus marginatus invadisse e colonizasse o alto rio Paraná. Este estudo teve por objetivos: i) confirmar através da microscopia de luz as fases reprodutivas das fêmeas de S. marginatus; ii) estimar a fecundidade e iii) avaliar as áreas de reprodução da população. Um total de 764 fêmeas foram amostrados em nove estações de amostragem na planície de inundação do alto rio Paraná. A análise microscópica dos ovários mostrou fêmeas nas subfases em desenvolvimento inicial, fase desenvolvimento, fase apto à desova, subfase desova ativa, fase regressão e fase regeneração. A distribuição de frequência dos oócitos mostra que a desova é parcelada e a fecundidade é indeterminada. A fecundidade variou de 410 a 752 e em média 584 oócitos. A desova contínua durante o longo período reprodutivo associado à agressividade em relação à defesa da prole garante o sucesso em deixar mais descendentes nas lagoas dos Patos, Ventura, Fechada, do Guaraná, das Garças, nos rios Ivinheima e Baia da planície de inundação do alto rio Paraná.

Descrição morfológica dos ovários do peixe Melanotaenia boesemani em atividade reprodutiva / Morphological description of Melanotaenia boesemani ovaries in reproductive activity

Estudou-se o tecido germinativo ovariano do peixe Melanotaenia boesemani. Por meio de análises morfológicas das gônadas, realizadas após a confecção de lâminas histológicas elaboradas em parafina e coradas com hematoxilina-eosina, foram descritos os tipos celulares encontrados e realizada a classificação do estádio de maturidade dos peixes. Macroscopicamente, foi identificado que a referida espécie possui ovário único, arredondado e, na fase observada, amarelado, localizado na parte látero-anterior da cavidade celomática. As fêmeas analisadas foram classificadas na escala de desenvolvimento gonadal como maduro/em reprodução. A presença de folículos vazios e marcas de desova nas lamelas ovulígeras mostrou-se evidente. Nos ovócitos vitelogênicos deste peixe, foi constatada a presença de filamentos de adesão ovocitária ancorados à zona pelúcida. Os ovários apresentaram aspecto morfológico geral semelhante ao de outros peixes teleósteos. Seu tipo de desova foi classificado como intermitente e o padrão de desenvolvimento de ovócitos, como assincrônico.(AU)

The germinal ovarian tissue of the fish Melanotaenia boesemani was studied. By means of morphological analyses of the gonads, performed after the manufacture of histological slides made of paraffin and stained with hematoxylin-eosin, the cell types found were described and the rank of the maturity stage of the fishes was executed. Macroscopically was found that the species has only one ovary, rounded and in the observed phase yellowish, located in the lateral front part of the coelomic cavity. The observed females were classified in the gonadal development scale as mature/in reproduction. The presence of empty follicles and spawning marks on ovigerous lamellae proved to be evident. In vitellogenic oocytes of this fish, the presence of filaments of oocyte adhesion anchored to the pellucida zona was found. The ovaries showed general morphological appearance similar to that of other teleost fishes. Its spawning type was classified as intermittent and the pattern of development of oocytes as asynchronous.(AU)

The reproductive biology of the Caspian green lizard, Lacerta strigata (Sauria: Lacertidae) in Iran / La biología reproductiva de la lagartija verde del Mar Caspio, Lacerta strigata (Sauria: Lacertidae) en Iran

The Caspian Green Lizard, Lacerta strigata Eichwald, 1831, is a member of the Lacertidae family distributed in the Caspian coast of northern Iran. The specimens were found in coastal dunes, hilly areas and pastureland containing some shrubby cover. In this research, the reproductive biology of this species was studied from April 20 to September 5, 2013. Forty eight adult specimens including 24 females and 24 males were collected by hand at midday from three sampling stations (Goharbaran, Ab-Bandansar and Ab-Bandankesh) of Sari County, located in Mazandaran Province of Iran. Ovaries and testes were removed and processed for histological and morphometric studies. In females, there were 6­17 follicles in each ovary. Totally, 6­10 oviductal eggs were observed in mature females. The oogenic and spermatogenic cycle begins from late March, mating starts from early May, with oviposition occurring from late May to late June, with the possibility of producing a secondary clutch later in the season. In males, the mean number and mean diameter of seminiferous tubules were 86.95 and 190.4750 microns, respectively. The mean diameter of tunica albuginea, germinal layer and lumen were 18.75, 69.79 and 144.27 microns, respectively. Maximum reproductive activity occurs from early May to early June, reduces from early July and ends in August. Hence, oogenesis and spermatogenesis occurs from April through July, L. strigata follows a seasonal reproductive cycle with associated type.

La lagartija verde, Lacerta strigata Eichwald, 1831 es un miembro de la familia Lacertidae distribuido en la costa del mar Caspio en el norte de Irán. Los especímenes se encontraron en las dunas costeras, zonas de colinas y pastos que contienen algo de cubierta arbustiva. En esta investigación, la biología reproductiva de esta especie fue estudiada del 20 de abril al 5 de septiembre de 2013. Cuarenta y ocho ejemplares adultos, incluyendo 24 hembras y 24 machos fueron recogidos a mano al mediodía en tres estaciones de muestreo (Goharbaran, Ab-Bandansar y AB- Bandankesh) del condado de Sari, ubicado en la provincia Mazandaran de Irán. Los ovarios y los testículos fueron retirados y procesados para estudios histológicos y morfométricos. En las hembras, se observaron 6­17 folículos en cada ovario. En total, se encontraron 6­10 huevos en los oviductos de hembras maduras. El ciclo oogénico y la espermatogénesis comenzaron a partir de fines de marzo, el apareamiento se inició desde principios de mayo con la oviposición ocurriendo desde fines de mayo hasta fines de junio. Las hembras depositan 6­10 huevos por puesta, con la posibilidad de producir una segunda puesta más adelante en la temporada. En los machos, el número medio y el diámetro medio de los túbulos seminíferos fueron 86,95 y 190,475 micras, respectivamente. El diámetro medio de túnica albugínea, la capa germinal y lumen fueron de 18,75, 69,79 y 144,27 micras, respectivamente. La actividad reproductiva máxima se produce desde principios de mayo hasta principios de junio, se reduce desde principios de julio y termina en agosto. Por lo tanto, la ovogénesis y espermatogénesis se producen a partir de abril a julio, L. strigata sigue una temporada ciclo reproductivo con tipo asociado.

Cellular development of the germinal epithelium during the gametogenic cycle of the golden mussel Limnoperna fortunei (Bivalvia: Mytilidae)

AbstractThe golden mussel Limnoperna fortunei is an invasive species that has quickly dispersed and colonized several potential different habitats distributed all over the world, causing environmental and economic impacts. Thus, in order to contribute to a better understanding of the reproductive aspects of L. fortunei, we described the cellular dynamic of the male and female germinal epithelium during the annual reproductive life history of this species, with the use of high resolution histology. An approximate of 1 200 specimens of L. fortunei were sampled periodically on the upper Paraná River floodplain (Brazil), from March 2010 to December 2012. Based on the activity of the germinal epithelium and consequent germ cell development, this study has resulted in the recognition of the following reproductive phases: Developing, Spawning Capable, Regressing and Regenerating. In the characterization of these phases, the following germ cells were described for males: spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa. Cell nests, oogonia, early prophase oocytes, previtellogenic oocytes and vitellogenic oocytes (early vitellogenic oocytes, middle vitellogenic oocytes and full-grown oocytes) were described for females. The morphological data and reproductive parameters obtained, showed the value of the cellular dynamics of the germinal epithelium, for the understanding of the cyclic gonadal events during the adult reproductive life of the mollusk in general. These results on the gametogenesis of this invasive species may be a fundamental tool for the development of control strategies and programs implementation, to reduce their proliferation and impacts in natural local environments. Rev. Biol. Trop. 64 (2): 521-536. Epub 2016 June 01.

ResumenEl mejillón dorado Limnoperna fortunei (Dunker, 1857) es una especie invasora que se ha dispersado rápidamente y ha colonizado diferentes hábitats potenciales distribuidos por todo el mundo, causando impactos ambientales y económicos. El control de esta especie depende del conocimiento de los aspectos reproductivos. Entre marzo 2010 y diciembre 2012 fueron muestreados periodicamente alrededor de 1 200 especímenes de L. fortunei en la planicie de inundación del Alto Rio Paraná, Brasil. Con el fin de contribuir con una mejor comprensión de los aspectos reproductivos de L. fortunei, se describió la dinámica celular del epitelio germinativo masculino y femenino durante la vida reproductiva anual de esta especie, mediante histología de alta resolución basada en la actividad del epitelio germinal y el consecuente desarrollo de las células germinales. En este estudio se reconocieron las siguientes fases reproductivas: desarrollo, capacidad de desove, regresión y regeneración. En los machos se describieron las siguientes células germinales: espermatogonias, espermatocitos primarios y secundarios, espermátidas y espermatozoides. Mientras que en las hembras se estudiaron: nidos celulares, ovogonias, ovocitos profásicos tempranos, ovocitos pre-vitelogénicos y ovocitos vitelogénicos (ovocitos vitelogénicos tempranos, ovocitos vitelogénicos y ovocitos completamente desarrollados).Los datos morfológicos y parámetros reproductivos que se muestran aquí confirman cómo la dinámica celular del epitelio germinal permite la comprensión de los acontecimientos cíclicos gonadales durante la vida reproductiva de adultos del molusco, en general. El conocimiento de la gametogénesis de esta especie invasora puede convertirse en una herramienta fundamental para el desarrollo de estrategias de control y aplicación de programas para disminuir su proliferación en ambientes naturales.

C30F12.4 influences oogenesis, fat metabolism, and lifespan in C. elegans

Reproduction, fat metabolism, and longevity are intertwined regulatory axes; recent studies in C. elegans have provided evidence that these processes are directly coupled. However, the mechanisms by which they are coupled and the reproductive signals modulating fat metabolism and lifespan are poorly understood. Here, we find that an oogenesis-enriched gene, c30f12.4, is specifically expressed and located in germ cells and early embryos; when the gene is knocked out, oogenesis is disrupted and brood size is decreased. In addition to the reproductive phenotype, we find that the loss of c30f12.4 alters fat metabolism, resulting in decreased fat storage and smaller lipid droplets. Meanwhile, c30f12.4 mutant worms display a shortened lifespan. Our results highlight an important role for c30f12.4 in regulating reproduction, fat homeostasis, and aging in C. elegans, which helps us to better understand the relationship between these processes.

Impact of glycosylation on the unimpaired functions of the sperm / 대한생식의학회지

One of the key factors of early development is the specification of competence between the oocyte and the sperm, which occurs during gametogenesis. However, the starting point, growth, and maturation for acquiring competence during spermatogenesis and oogenesis in mammals are very different. Spermatogenesis includes spermiogenesis, but such a metamorphosis is not observed during oogenesis. Glycosylation, a ubiquitous modification, is a preliminary requisite for distribution of the structural and functional components of spermatids for metamorphosis. In addition, glycosylation using epididymal or female genital secretory glycans is an important process for the sperm maturation, the acquisition of the potential for fertilization, and the acceleration of early embryo development. However, nonemzymatic unexpected covalent bonding of a carbohydrate and malglycosylation can result in falling fertility rates as shown in the diabetic male. So far, glycosylation during spermatogenesis and the dynamics of the plasma membrane in the process of capacitation and fertilization have been evaluated, and a powerful role of glycosylation in spermatogenesis and early development is also suggested by structural bioinformatics, functional genomics, and functional proteomics. Further understanding of glycosylation is needed to provide a better understanding of fertilization and embryo development and for the development of new diagnostic and therapeutic tools for infertility.

Signaling Pathways in Insulin- and IGF-I Mediated Oocyte Maturation in Lower Vertebrates.

The endocrine control of oocyte maturation in fish and amphibians has proved to be a valuable model for investigating the rapid and non-genomic steroid actions at the cell surface. Considerable progress has made over the last decade in elucidating signaling pathways in steroid-induced oocyte maturation. In addition to steroids, various growth factors have also been reported to be involved in this process and progress being made to elucidate their mechanism of actions. Exposure of fully-grown oocytes to steroids or growth factors (insulin/IGFs) initiates various signaling cascade, leading to formation and activation of maturation-promoting factor (MPF), a key enzyme that catalyzes entry into M-phase of meiosis I and II. Whereas the function of MPF in promoting oocyte maturation is ubiquitous, there are differences in signaling pathways between steroids- and growth factors-induced oocyte maturation in amphibian and fish. Here, we have reviewed the recent advances on the signaling pathways in insulin- and IGF-I-induced oocyte maturation in these two groups of non-mammalian vertebrates. New findings demonstrating the involvement of PI3 kinase and MAP kinase in induction of oocyte maturation by insulin and IGF-I are presented.

Histological description of oogenesis in chiton virgulatus (Mollusca: Polyplacophora) / Descripción histológica de la ovogénesis de chiton virgulatus (Mollusca: Polyplacophora)

This paper describes the oogenesis of Chiton virgulatus, based on histological observations under transmission and scanning electron microscopy. Three oocyte types were identified: i) previtellogenic oocytes with a mean diameter of 50±20.5 µm, surrounded by elongated follicular cells of approximately 5 µm, ii) immature vitellogenic oocytes with a mean diameter of 113±15.3 µm and small cytoplasmic projections denoting the onset of the oocyte hull development; adjacent to each projection are pores approximately 0.7 µm in diameter, and iii) mature vitellogenic oocytes with a mean diameter of 146±24.8 µm; the oocyte cytoplasmic projections grow and its apical zone becomes trident-shaped; follicular cells adopt a bulbous shape due to the growth of the elongation and can reach up to 20 µm in length. The morphology and ultrastructure of the projections of the mature vitellogenic oocyte, as well as the size of pores at their base, are specific to C. virgulatus; therefore, these features could be used in taxonomic or fertilization studies.

En el presente trabajo se describe la ovogénesis de Chiton virgulatus, utilizando histología y las técnicas de microscopía electrónica de barrido y de transmisión. Se identificaron tres tipos de ovocitos: i) ovocitos previtelogénicos con un diámetro promedio de 50±20,5 µm, rodeados por células foliculares de forma alargada y un tamaño de aproximadamente 5 µm, ii) ovocitos vitelogénicos inmaduros con un diámetro promedio de 113±15,3 µm, este tipo de ovocitos presentan pequeñas proyecciones citoplasmáticas, que indican el inicio del desarrollo del casco del ovocito. Adyacentes a cada prolongación se presentan poros con un diámetro aproximado de 0,7 µm y iii) ovocitos vitelogénicos maduros con un diámetro promedio de 146±24,8 µm, las proyecciones citoplasmáticas del casco del ovocito crecen y en su parte apical adquieren la forma de un tridente, las células foliculares, dado el crecimiento de la prolongación toman el aspecto bulboso y llegan a medir hasta 20 µm de longitud. La morfología y la ultraestructura de las proyecciones del casco del ovocito vitelogénico maduro, así como el tamaño del poro en la base de las proyecciones son particulares para C. virgulatus, dichas características podrían ser utilizadas en trabajos de taxonomía y fertilización.