Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae

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Beçak Maria Luiza

2003-01-01

Full Text Available The positioning of macrochromosomes of Bothrops jararaca and Bothrops insularis (Viperidae was studied in undistorted radial metaphases of uncultured cells (spermatogonia and oogonia not subjected to spindle inhibitors. Colchicinized metaphases from uncultured (spleen and intestine and cultured tissues (blood were also analyzed. We report two antagonic non-random chromosome arrangements in untreated premeiotic cells: the parallel configuration with homologue chromosomes associated side by side in the metaphase plate and the antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphase ring. The antiparallel aspect also appeared in colchicinized cells. The spatial chromosome arrangement in both configurations is groupal size-dependent and maintained through meiosis. We also describe, in untreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. In B. jararaca males we observed that some gonad regions present changes in the meiotic mechanism. In this case, endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicated second metaphases of meiosis with the suppression of first meiosis. By a successive division, these cells form nuclei with one set of chromosomes. Chromosome doubling in oogonia is known in hybrid species and in parthenogenetic salamanders and lizards. This species also presented chromosome rearrangements leading to aneuploidies in mitosis and meiosis. It is suggested that somatic pairing, endomitosis, meiotic alterations, and chromosomal aberrations can be correlated processes. Similar aspects of nuclei configurations, endomitosis and reductional mitosis were found in other Viperidae and Colubridae species.

Sex-specific differences in fetal germ cell apoptosis induced by ionizing radiation

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Guerquin, M.J.; Duquenne, C.; Coffigny, H.; Rouiller-Fabre, V.; Lambrot, R.; Habert, R.; Livera, G. [CEA, DSV/DRR/SEGG/LDRG, Laboratory of Differentiation and Radiobiology of the Gonads, Unit of Gametogenesis and Genotoxicity, F-92265 Fontenay aux Roses (France); Guerquin, M.J.; Duquenne, C.; Coffigny, H.; Rouiller-Fabre, V.; Lambrot, R.; Habert, R.; Livera, G. [Univ. Paris 7-Denis Diderot, UFR of Biology, UMR-S 566, F-92265 Fontenay aux Roses (France); Guerquin, M.J.; Duquenne, C.; Coffigny, H.; Rouiller-Fabre, V.; Lambrot, R.; Habert, R.; Livera, G. [INSERM, U566, F-92265 Fontenay aux Roses (France); Bakalska, M. [Institute of Experimental Morphology and Anthropology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Frydman, R. [Univ Paris-Sud, Clamart F-92140 (France); Frydman, R. [AP-HP, Service de Gynecologie-Obstetrique et Medecine de la Reproduction, Hopital Antoine Beclere, Clamart F-92141 (France); Frydman, R. [INSERM, U782, Clamart F-92140 (France)

2009-07-01

Background: We have previously shown that male human fetal germ cells are highly radiosensitive and that their death depends on p53 activation. Male germ cell apoptosis was initiated with doses as low as 0.1 Gy and was prevented by pifithrin {alpha}, a p53 inhibitor. In this study, we investigated the radiosensitivity of early female and male fetal proliferating germ cells. Methods and results: Both male and female fetal germ cells displayed a similar number of {gamma}H2AX foci in response to ionizing radiation (IR). In organ culture of human fetal ovaries, the germ cells underwent apoptosis only when exposed to high doses of IR (1.5 Gy and above). Accumulation of p53 was detected in irradiated male human fetal germ cells but not in female ones. Inhibition of p53 with pifithrin {alpha} did not affect oogonia apoptosis following irradiation. IR induced apoptosis similarly in mouse fetal ovaries in organ culture and in vivo during oogonial proliferation. Germ cell survival in testes from p53 knockout or p63 knockout mice exposed to IR was better than wild-type, whereas female germ cell survival was unaffected by p53 or p63 knockout. Conclusions: These findings show that pre-meiotic male and female fetal germ cells behave differently in response to a genotoxic stress-irradiation with oogonia being less sensitive and undergoing p53-independent apoptosis. (authors)

Occurrence and ultrastructural characterization of "nuage" during oogenesis and early spermatogenesis of Piaractus mesopotamicus Holmberg, 1887 (Teleostei

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F. C. Abdalla

Full Text Available We investigated the occurrence and ultrastructurally characterized electrondense nuclear material (nuage released from the nucleus during oogenesis and early spermatogenesis of Piaractus mesopotamicus, a fish from Pantanal Matogrossense (Brazil having a seasonal reproductive cycle. The female germ cells presented two instances of nuclear material extrusion: in the oogonia and in the oocyte in the perinucleolar phase. In males, material with similar morphology and behavior occurred in the spematogonia. In all cases, this material was associated to mitochondria. The possible function of this material is discussed.

Phytophthora terminalis sp. nov. and Phytophthora occultans sp. nov., two invasive pathogens of ornamental plants in Europe.

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Man In 't Veld, Willem A; Rosendahl, Karin C H M; van Rijswick, Patricia C J; Meffert, Johan P; Westenberg, Marcel; van de Vossenberg, Bart T L H; Denton, Geoff; van Kuik, Fons A J

2015-01-01

In the past decade several Phytophthora strains were isolated from diseased Pachysandra terminalis plants suffering stem base and root rot, originating from the Netherlands and Belgium. All isolates were homothallic and had a felt-like colony pattern, produced semi-papillate sporangia, globose oogonia and had a maximum growth at ~ 27 C. Several additional Phytophthora strains were isolated from diseased Buxus sempervirens plants, originating from the Netherlands and Belgium, which had sustained stem base and root rot; similar strains also were isolated from Acer palmatum, Choisya ternata and Taxus in the United Kingdom. All isolates were homothallic and had a stellate colony pattern, produced larger semi-papillate sporangia and smaller globose oogonia than the isolates from Pa. terminalis and had a maximum growth temperature of ~ 30 C. Phylogenetic analyses of both species using the internal transcribed spacer region of the nuc rDNA (ITS), mt cytochrome oxidases subunit I gene (CoxI) and nuc translation elongation factor 1-α gene (TEF1α) revealed that all sequences of each species were identical at each locus and unique to that species, forming two distinct clusters in subclade 2a. Sequence analysis of partial β-tubulin genes showed that both taxa share an identical sequence that is identical to that of Ph. himalsilva, a species originating from Asia, suggesting a common Asian origin. Pathogenicity trials demonstrated disease symptoms on their respective hosts, and re-isolation and re-identification of the inoculated pathogens confirmed Koch's postulates. © 2015 by The Mycological Society of America.

Dynamics and cytochemistry of oogenesis in Leporinus striatus Kner (Teleostei, Characiformes, Anostomidae from the Rio Sapucaí, Minas Gerais State, Brazil

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Helena A.S. Chini

2001-12-01

Full Text Available Oogenesis involves a sequense of transformations which are undergone by female germ cells. These cells change into oogonias and then into mature oocytes. Sexually mature females were collected monthly, during one year, from the Rio Sapucaí, tributary of the Rio Grande, which is part of the Furnas Reservoir system in the state of Minas Gerais. The observed material showed that oogonias were small spherical cells, had a big spherical nucleus, with a single nucleolus, and weakly stained cytoplasm with eosinophilic granules (FG stained, which indicate their protein content. The primary oocytes showed a big basophilic nucleus, with a large peripheral nucleolus, and several smaller nucleoli. They show a reduced cytoplasmic content. The previtellogenic oocytes presented voluminous cytoplasm and nucleus with several small peripheral nucleoli. The oocytes underwent vitellogenesis with the development of the zona radiata and the follicle cells. The zona radiata had two layers, the outer and the inner, which showed its protein content when stained with CM and FG techniques. TB pH 2.5 and pH 4.0 staining showed that oocytes undergoing vitellogenesis presented weakly stained cytoplasm and peripheral cytoplasmic vesicles. The follicle cells that were squamous became cuboidal. In mature oocytes, the yolk granules that filled the cytoplasm became green and blue when stained with FG and CM techniques, indicating their protein content. The perivitclline region showed rosy stained vesicles (TB pH 2.5 and pH 4.0 spread among the weakly stained peripheral vesicles, which seemed to be the cortical alveoli. The zona radiata cells, CM and FG stained, still showed two layers like the oocytes from the previous stage, but thicker.

A new model of development of the mammalian ovary and follicles.

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Katja Hummitzsch

Full Text Available Ovarian follicular granulosa cells surround and nurture oocytes, and produce sex steroid hormones. It is believed that during development the ovarian surface epithelial cells penetrate into the ovary and develop into granulosa cells when associating with oogonia to form follicles. Using bovine fetal ovaries (n = 80 we identified a novel cell type, termed GREL for Gonadal Ridge Epithelial-Like. Using 26 markers for GREL and other cells and extracellular matrix we conducted immunohistochemistry and electron microscopy and chronologically tracked all somatic cell types during development. Before 70 days of gestation the gonadal ridge/ovarian primordium is formed by proliferation of GREL cells at the surface epithelium of the mesonephros. Primordial germ cells (PGCs migrate into the ovarian primordium. After 70 days, stroma from the underlying mesonephros begins to penetrate the primordium, partitioning the developing ovary into irregularly-shaped ovigerous cords composed of GREL cells and PGCs/oogonia. Importantly we identified that the cords are always separated from the stroma by a basal lamina. Around 130 days of gestation the stroma expands laterally below the outermost layers of GREL cells forming a sub-epithelial basal lamina and establishing an epithelial-stromal interface. It is at this stage that a mature surface epithelium develops from the GREL cells on the surface of the ovary primordium. Expansion of the stroma continues to partition the ovigerous cords into smaller groups of cells eventually forming follicles containing an oogonium/oocyte surrounded by GREL cells, which become granulosa cells, all enclosed by a basal lamina. Thus in contrast to the prevailing theory, the ovarian surface epithelial cells do not penetrate into the ovary to form the granulosa cells of follicles, instead ovarian surface epithelial cells and granulosa cells have a common precursor, the GREL cell.

Effect of radiation on the early period of gametogenesis in Tilapia mossambika Peters

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Chmilevskij, D.A.; Ivojlov, A.A.

1978-01-01

Tilapia mossambica Peters larvae 10 days after hatching were X-irradiated at 350 R, and the number of germinative cells at different stages of development was followed. In the control, 10-day larvae possessed primordial germ cells and gonia; 15-day larvae had mostly gonia; in 20-day larvae some gonia were entering early prophase of meiosis; 25-day larvae possessed gonia and early meiotic prophase oocytes; and 30-day larvae had oogonia, oocytes at early prophase and at the previtellogenesis stage. After the irradiation, 13- and 14-day larvae showed some mitotic disturbances; however the mass death of germ cells was observed after their entering the pachytene stage in fishes 25 days old

Radioautographic study of RNA synthesis in Caenorhabditis elegans (Bergerac variety) oogenesis

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Starck, Joelle

1977-01-01

An original method of incubation allowing the use of radioactive precursor for RNA synthesis study, is described. This in vitro incubation technique offers the advantages of: being simple (it does not require axenic culture as various authors concluded when they attempted nematode labelling); being rapid (in vivo system requires 20 to 24 hours incubation to obtain labelling); being repeatable (the ten different preparations of each of our experiments behave in a very homogeneous way). Then, this technique offers a great interest to study: the kinetic of RNA synthesis in oogonia and oocytes, and also in the rachis, specific to nematodes of which function is poorly understood; the reproduction of this hermaphroditic C. elegans as compared in the wild-type and in the thermosensitive or female sterile mutants

New data on distribution, morphology and ecology of Oedogonium capillare Kützing ex Hirn (Oedogoniales, Chlorophyta in Poland

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Marta Pikosz

2015-12-01

Full Text Available Algological investigations were focused on taxonomy, chorology and ecology of threatened filamentous green alga species in Poland. Studies on Oedogonium capillare Kützing ex Hirn growing in large quantities in association with Cladophora rivularis (Linnaeus Hoek in pond were conducted. The aim of these studies was to describe the distribution, ecology and morphology of O. capillare as part of a more comprehensive study of this filamentous green alga. It is the eighth record in Poland for O. capillare. Filaments of O. capillare were grown over a wide pH range (7.3-9.6 and in high variability of nutrients. Vegetative cells, oogonia and antheridia were observed, which allowed taxonomic identification. O. capillare occurs in eutrophic waters which requires protection of its habitat.

Radioautographic study of RNA synthesis in Caenorhabditis elegans (Bergerac variety) oogenesis. [Nematode

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Starck, J [Lyon-1 Univ., 69 - Villeurbanne (France)

1977-11-01

An original method of incubation allowing the use of radioactive precursor for RNA synthesis study, is described. This in vitro incubation technique offers the advantages of: being simple (it does not require axenic culture as various authors concluded when they attempted nematode labelling); being rapid (in vivo system requires 20 to 24 hours incubation to obtain labelling); being repeatable (the ten different preparations of each of our experiments behave in a very homogeneous way). Then, this technique offers a great interest to study: the kinetic of RNA synthesis in oogonia and oocytes, and also in the rachis, specific to nematodes of which function is poorly understood; the reproduction of this hermaphroditic C. elegans as compared in the wild-type and in the thermosensitive or female sterile mutants.

Desenvolvimento morfológico dos ovários em embriões e fetos bovinos da raça Nelore Morphological development of the ovaries in embryos and fetuses of Nelore breed

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E.G. Diniz

2005-02-01

Full Text Available Investigaram-se os eventos morfológicos relacionados ao desenvolvimento pré-natal de ovários de 81 embriões e fetos da raça Nelore, coletados em frigoríficos, com idades variando de 26 a 240 dias pós-fecundação. Observou-se formação da crista gonádica e presença de células germinativas em seu interior aos 29 e 34 dias, respectivamente. As oogônias e folículos primordiais, ao contrário dos folículos em crescimento, apresentaram diferenças significativas de diâmetro nos vários períodos estudados. Verificou-se correlação positiva (PThe morphologic events related to the prenatal development of the ovaries in 81 Nelore breed embryos and fetuses gathered in a local slaughterhouse, with age range from 26 to 240 days following fecundation were studied. The age of fetuses was estimated from measures taken in the cranium-caudal direction. The sex was identified from macroscopic observations and using Polymerase Chain Reaction (PCR technique. For histology the gonads were fixed in Bouin’s fluid for 24 hours and 5 µm thick section’s were stained with hematoxylin-eosin. Formation of gonadal ridge and presence of germinal cells were found within it at 29 and 34 days, respectively. Oogonia and primordial follicles, unlike the growing follicles, exhibited significant differences in diameter in the various periods studied. Positive correlation (P<0.05 was found between the diameter of oogonia and their nucleus as well as between primordial and growing follicles with their oocytes and respective nuclei. The gonad was fully formed at 40 days. Primordial follicles, in the growing stage, and antral follicles first appeared, approximately at 95, 140, and 180 days, respectively. Despite the onset and duration of oogenesis being similar to that of taurine breeds, folliculogenesis initiates at an early stages in the Nelore breed.

Female reproductive traits of a commercially exploited skate: Atlantoraja platana (Günther, 1880) (Chondrichthyes, Rajidae). Ovarian morphology, gametogenesis and microscopic verification of maturity criteria.

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Moya, A C; Wehitt, A; Díaz Andrade, M C; Di Giacomo, E E; Galíndez, E J

2017-10-01

Atlantoraja platana is an endemic species of the Southwest Atlantic Ocean, and is one of the most captured by the local bottom trawl industrial fisheries. In this work, the microscopic architecture of mature female's gonads and the dynamics of follicle development are studied as a contribution to raise awareness of reproductive biology of the species. Folliculogenesis depicts the same histologic pattern as in other Elasmobranchs. Follicles in different degrees of maturation coexist in mature animals. The oogonia were only found in immature individuals. Likewise, atretic follicles were recorded in ovaries of all sexual maturity stages. The microscopic size recorded from the beginning of yolk input is smallest than the detected with the necked eye. This study provides valuable information about female's gametogenesis that could be taken into account in the development of fisheries management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neutron-induced mutation experiments. Comprehensive report, March 1, 1977-August 31, 1980

International Nuclear Information System (INIS)

Abrahamson, S.

1981-02-01

Neutron-induced X-linked lethal mutations were induced in Drosophila melanogaster oogonia at energies of .43, .66, 2, and 6 MeV. The 37 irradiations were carried out at the RARAF facility at Brookhaven National Laboratory. RBE's (relative to x-ray data similarly collected) were calculated to be .43 MeV to 4.8; .66 MeV to 4.0; 2 MeV to 3.2; and 6 MeV to 2.9. The dose/frequency response curves for all energies best fit a linear rather than a linear-quadratic model following regression analyses. Control data for specific locus mutations (420,000 tests) were gathered. This data, combined with other data (both X-linked lethal and specific locus) has been used to estimate the number of loci on the X-chromosome of Drosophila which can mutate to recessive lethals

Neutron-induced mutation experiments. Progress report, March 1, 1975--February 29, 1976

International Nuclear Information System (INIS)

Abrahamson, S.

1975-11-01

The relative mutagenic effectiveness of neutrons of different energies were compared with x radiation in mice and Drosophila oogonia employing X-linked recessive lethal and specific locus mutation tests. The energies and doses used were 0.68 MeV, 2 MeV, and 6 MeV (250 and 500 0 R), and 15 MeV (250, 500, and 1000 0 R). The data thus far collected from the recessive lethal test indicate that 0.68 MeV neutrons have the highest RBE among the energies tested, followed by 6 and 2 MeV. The specific locus mutation data also indicate the highest RBE for 0.68 MeV, followed respectively by 2 and 6 MeV. The 15 MeV data is as of now incompletely analyzed, as are some dose points of 2 and 6 MeV

RSPO1/β-catenin signaling pathway regulates oogonia differentiation and entry into meiosis in the mouse fetal ovary

NARCIS (Netherlands)

Chassot, Anne-Amandine; Gregoire, Elodie P.; Lavery, Rowena; Taketo, Makoto M.; de Rooij, Dirk G.; Adams, Ian R.; Chaboissier, Marie-Christine

2011-01-01

Differentiation of germ cells into male gonocytes or female oocytes is a central event in sexual reproduction. Proliferation and differentiation of fetal germ cells depend on the sex of the embryo. In male mouse embryos, germ cell proliferation is regulated by the RNA helicase Mouse Vasa homolog

RSPO1/beta-Catenin Signaling Pathway Regulates Oogonia Differentiation and Entry into Meiosis in the Mouse Fetal Ovary

NARCIS (Netherlands)

Chassot, A.A.; Gregoire, E.P.; Lavery, R.; Taketo, M.M.; de Rooij, D.G.; Adams, I.R.; Chaboissier, M.C.

2011-01-01

Differentiation of germ cells into male gonocytes or female oocytes is a central event in sexual reproduction. Proliferation and differentiation of fetal germ cells depend on the sex of the embryo. In male mouse embryos, germ cell proliferation is regulated by the RNA helicase Mouse Vasa homolog

RSPO1/β-catenin signaling pathway regulates oogonia differentiation and entry into meiosis in the mouse fetal ovary.

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Anne-Amandine Chassot

Full Text Available Differentiation of germ cells into male gonocytes or female oocytes is a central event in sexual reproduction. Proliferation and differentiation of fetal germ cells depend on the sex of the embryo. In male mouse embryos, germ cell proliferation is regulated by the RNA helicase Mouse Vasa homolog gene and factors synthesized by the somatic Sertoli cells promote gonocyte differentiation. In the female, ovarian differentiation requires activation of the WNT/β-catenin signaling pathway in the somatic cells by the secreted protein RSPO1. Using mouse models, we now show that Rspo1 also activates the WNT/β-catenin signaling pathway in germ cells. In XX Rspo1(-/- gonads, germ cell proliferation, expression of the early meiotic marker Stra8, and entry into meiosis are all impaired. In these gonads, impaired entry into meiosis and germ cell sex reversal occur prior to detectable Sertoli cell differentiation, suggesting that β-catenin signaling acts within the germ cells to promote oogonial differentiation and entry into meiosis. Our results demonstrate that RSPO1/β-catenin signaling is involved in meiosis in fetal germ cells and contributes to the cellular decision of germ cells to differentiate into oocyte or sperm.

A new vision of the origin and the oocyte development in the Ostariophysi applied to Gymnotus sylvius (Teleostei: Gymnotiformes

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Gisleine Fernanda França

Full Text Available Based on new knowledge coming from marine perciform species, the origin of oocytes and their development in the Ostariophysi, Gymnotus sylvius is described. In both Gymnotus sylvius and marine perciform fish, oogonia are found in the germinal epithelium that forms the surface of the ovarian lamellae. At the commencement of folliculogenesis, proliferation of oogonia and their entrance into meiosis gives rise to germ cell nests that extend into the stroma from the germinal epithelium. Both cell nests and the germinal epithelium are supported by the same basement membrane that separates them from the stroma. At the time of meiotic arrest, oocytes in a cell nest become separated one from the other as processes of prefollicle cells, these being derived from epithelial cells in the germinal epithelium, gradually encompass and individualize them while also synthesizing a basement membrane around themselves during folliculogenesis. The oocyte enters primary growth while still within the cell nest. At the completion of folliculogenesis, the oocyte and follicle cells, composing the follicle, are encompassed by a basement membrane. The follicle remains connected to the germinal epithelium as the both share a portion of common basement membrane. Cells originating from the stroma encompass the ovarian follicle, except where there is a shared basement membrane, to form the theca. The follicle, basement membrane and theca form the follicular complex. Oocyte development occurs inside the follicular complex. Development is divided into the stages primary and secondary growth, oocyte maturation and ovulation. Cortical alveoli appear in the ooplasm just prior to the beginning of secondary growth, the vitellogenic stage that begins with yolk deposition and proceeds until the oocyte is full-grown and the ooplasm is filled with yolk globules. Maturation is characterized by the germinal vesicle or nuclear migration, germinal vesicle breakdown or nuclear envelop

Ultrastructure of oogenesis in imposex females of Babylonia areolata (Caenogastropoda: Buccinidae)

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Muenpo, C.; Suwanjarat, J.; Klepal, W.

2011-09-01

During a tributyltin (TBT)-exposure experiment, the ultrastructural features of oogenesis have been examined in TBT-induced imposex females of Babylonia areolata and compared with those of the normal female. The results obtained from such experiment demonstrates that B. areolata exhibits a low to moderate intensity of imposex because all VDSI values are never higher than 3. Ultrastructures of germ cell development including oogonia, pre-vitellogenic, early vitellogenic, late vitellogenic and mature oocytes show that oogenesis in imposex female is similar to that of normal females except for the presence of numerous lipid droplets in the cytoplasm of the oocytes and the follicle cells in imposex females, indicating the degeneration of their oocytes. Vitellogenesis in B. areolata involves both auto- and heterosynthetic processes that resemble those of the basal gastropods and the pulmonates. In addition, the presence of cortical granules and microvilli are unique structures of this species.

Histoarchitecture of the Ovary of Rhipicephalus (Boophilus) annulatus during Pre- and Postengorgement Period

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Kanapadinchareveetil, Sreelekha; Chandrasekhar, Leena; Gopi, Jyothimol; Ranjan Lenka, Dibya; Vasu, Aswathi; KGopalan, Ajith Kumar; Nair, Suresh N.; Juliet, Sanis; Ghosh, Srikanta

2015-01-01

The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium. PMID:25664337

Neutron-induced mutation experiments and total radiation-induced genetic damage in entire genomes of Drosophila melanogaster. Final report, November 1, 1967-August 31, 1980

International Nuclear Information System (INIS)

Abrahamson, S.

1981-02-01

Neutron-induced mutation experiments with Drosophila oogonia were conducted at the University of Wisconsin, with irradiations being carried out at the RARAF facility at Brookhaven National Laboratory. X-linked recessive lethals and specific locus mutations were studied. Using the α value of the weighted linear regression equation for lethal data, RBE's relative to X-rays were calculated for the energies of neutrons studied. They are: 15 MeV to 2.0; 6 MeV to 2.9; 2 MeV to 3.2; .66 MeV to 4.0; .43 MeV to 4.8. The dose/frequency response curves for lethal data of all neutron energies studied was suggestive of a quadratic component. All data best fit a linear hypothesis, however. Control data for specific locus mutations was used to estimate the number of loci on the X-chromosome which are capable of mutating to lethals. Neutron-induced data for specific locus mutation was inconclusive due to the high error inherent in the frequencies obtained

Wolbachia infect ovaries in the course of their maturation: last minute passengers and priority travellers?

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Lise-Marie Genty

Full Text Available Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH, we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers.

Influence of X-rays on oogenesis of Oreochromis mossambicus Peters

International Nuclear Information System (INIS)

Chmilevskij, D.A.; Mel'nikova, I.V.

1988-01-01

The fry at the age of 30 and 60 days after hatching were X-irradiated (350 R) and the gonads were studied until the age of 120 days. Previtellogenic oocytes, which were the older generation in the experimental fishes, were more resistant than oogonia and oocytes at various stages of the early meiotic prophase, the number of the latter having been gretly reduced. In some previtellogenic oocytes the nucleus and cytoplasm were damaged, leading to their death. When the 30 day old fishes were irradiated, the nuclei of the previtellogenic oocytes were fragmented. Within 30 days after irradiation of the 60 day old fishes bud-like evaginations of the nuclear envelope appeared in the early vitellogenic oocytes, their function and fate being unclear. The fishes irradiated at the age of 60 days had by 120 days much lesser previtellogenic oocytes than the control fishes; this might decrease the fecundity of fishes in the second spawning

Pharmacognostical study and phytochemical evaluation of brown seaweed Sargassum wightii

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Jeyaraman Amutha Iswarya Devi

2013-10-01

Full Text Available Objective: To explore the pharmacognostical and phytochemical properties of Sargassum wightii. Methods: The qualitative microscopy, phytochemical screening, physicochemical evaluation and fluorescence analysis of the plant were carried out according to the standard procedure recommended in the WHO guidelines. Results: Macroscopic study showed that plants were dark brown, 20-30 cm in height, leaves were 5-8 cm length, shape: linear to ovate, apex: midrib in conspicuous and having the entire, serrate margin. Microscopic evaluation of the transverse section of the leaf, stem, air bladder, receptacles showed the presence of epidermis layer followed by thick cuticle, conducting strand, mesophyll and possessed antheridia or oogonia at the swollen terminal portions. The different extracts of Sargassum wightii showed the presence of steroids, alkaloids, phenolic compounds, saponins and flavonoids with varied degree. Conclusions: Various pharmacognostical parameters evaluated in this study help in the identification and standardization of the of the seaweed Sargassum wightii

Morphological indicators of initial reproductive commitment in Mustelus schmitti (Springer 1939 (Chondrichthyes, Triakidae: folliculogenesis and ovarian structure over the life cycle

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EJ Galíndez

Full Text Available This work provides information about the sexual commitment and the folliculogenesis of the gatuzo, Mustelus schmitti. A total of 112 females of all maturity stages were fished in the Bahía Blanca estuary, between 2009 and 2010. The oogonia were present throughout the life cycle of the animals. The folliculogenesis follows a pattern similar to other elasmobranchs. The granulosa layer keeps monolayered throughout the folliculogenesis, but with two cell types in the vitellogenic follicle. The zona pellucida forms in the primordial follicles. The thecal system shows a connective inner layer and a glandular outer sheath. The microscopic beginning of the sexual commitment, indicated by the vitello hoarding, takes place in follicles from 500 micrometres, while the macroscopic evidence appears in follicles of 2500-3000 micrometres. The results presented in this study suggest that the fishery pressure may affect a susceptible range of sizes of the species, not previously considered and provides a biological framework for the development of fisheries policy.

A potential germ cell-specific marker in Japanese flounder, Paralichthys olivaceus: identification and characterization of lymphocyte antigen 75 (Ly75/CD205)

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Yang, Yang; Liu, Qinghua; Ma, Daoyuan; Song, Zongchen; Li, Jun

2018-04-01

Some germ cell marker genes, such as vasa, nanos, and dead end (dnd), have been identified in fish. Recently, lymphocyte antigen 75 (Ly75/CD205) has been identified as a mitotic germ cell-specific cell-surface marker in several fish species. In this study, the Japanese flounder ly75 homolog (ly75) was cloned and its expression pattern in gonads was analyzed. The full-length cDNA of ly75 was 7 346 bp, with an open reading frame (ORF) of 5 229 bp. The ORF encoded a protein containing 1 742 amino acids with a predicted molecular mass of 196.89 kDa. In adult tissues, ly75 transcripts were detected in all analyzed tissues but abundantly in the testis. In in-situ hybridization analyses, ly75 mRNA was predominantly localized in oocytes in the ovary and spermatogonia in the testis, but ly75 mRNA was not detected in oogonia, spermatocytes, spermatids, or spermatozoa. These results indicated that ly75 could be a potential germ cell-specific marker in P. olivaceus, as in other fishes.

Phytophthora pseudopolonica sp. nov., a new species recovered from stream water in subtropical forests of China.

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Li, Wen-Wen; Zhao, Wen-Xia; Huai, Wen-Xia

2017-09-01

A new species of the genus Phytophthora was isolated from stream water in the subtropical forests of China during a survey of forest Phytophthora from 2011 to 2013. This new species is formally described here and named Phytophthora pseudopolonica sp. nov. This new homothallic species is distinct from other known Phytophthora species in morphology and produces nonpapillate and noncaducous sporangia with internal proliferation. Spherical hyphal swellings and thin-walled chlamydospores are abundant when the species is kept in sterile water. The P. pseudopolonica sp. nov. forms smooth oogonia with paragynous and sometimes amphigynous antheridia. The optimum growth temperature of the species is 30 °C in V8-juice agar with β-sitosterol, yet it barely grows at 5 °C and 35 °C. Based on sequences of the internal transcribed spacer and the combined β-tubulin and elongation factor 1α gene sequence data, isolates of the new species cluster together into a single branch and are close to Phytophthora polonicabelonging to clade 9.

Endocrine modulation, inhibition of ovarian development and hepatic alterations in rainbow trout exposed to polluted river water

Energy Technology Data Exchange (ETDEWEB)

Vigano, Luigi, E-mail: vigano@irsa.cnr.i [Water Research Institute, National Council of Research, Brugherio, Milan (Italy); Benfenati, Emilio [Mario Negri Institute, Laboratory of Environmental Chemistry and Toxicology, Milan (Italy); Bottero, Sergio; Cevasco, Alessandra; Monteverde, Martino; Mandich, Alberta [Department of Environmental, Experimental and Applied Biology, University of Genoa, Genoa (Italy)

2010-12-15

Under laboratory conditions, female rainbow trout were exposed to graded concentrations of water from the River Lambro, a polluted tributary of the River Po, and to the effluent of a large wastewater treatment plant which flows into the River Lambro. In field exposures, trout were held in cages in the River Po upstream and downstream from the confluence of the River Lambro. After 10-day (laboratory) and 30-day (laboratory and field) exposures, trout were examined for several chemical, biochemical and histological endpoints. The results indicated that exposure to complex mixtures of chemicals, including estrogen receptor agonists, aryl-hydrocarbon receptor agonists, and probably antiandrogens, had occurred. Exposure altered the plasma levels of 17{beta}-estradiol and testosterone, and some treatments also enhanced the activity of hepatic ethoxyresorufin O-deethylase. Gonadal histology showed varying levels of degenerative processes characterised by oocyte atresia, haemorrhages, melano-macrophage centres (MMCs), and oogonia proliferation. Liver histology showed less severe effects. - This study examined the progression of hormonal and gonadal alterations in female trout exposed to river water from an area known to affect resident fish species.

On the presence of fertile gametophytes of Padina pavonica (Dictyotales, Phaeophyceae from the Iberian coasts

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Gómez Garreta, Amelia

2007-06-01

Full Text Available The gametophytes of Padina pavonica (L. Thivy have received little attention in literature. Both female and predominantly male monoecious gametophytes of P. pavonica are recorded for the first time in the Iberian Peninsula. A detailed description of the morphology and the disposition of oogonia and antheridia is presented. In addition, a comparison with literature data on this and other Padina species is carried out.Los gametófitos de Padina pavonica (L. Thivy han sido escasamente reseñados en la bibliografía. En este trabajo se señala por primera vez en las costas de la Península Ibérica la presencia de gametófitos fértiles de P. pavonica, tanto femeninos como monoicos predominantemente masculinos. Se presenta una detallada descripción de la disposición y la morfología de los oogonios y anteridios. Asimismo, se realiza una comparación con los datos bibliográficos de esta especie y con los de otras especies de Padina

Endocrine modulation, inhibition of ovarian development and hepatic alterations in rainbow trout exposed to polluted river water

International Nuclear Information System (INIS)

Vigano, Luigi; Benfenati, Emilio; Bottero, Sergio; Cevasco, Alessandra; Monteverde, Martino; Mandich, Alberta

2010-01-01

Under laboratory conditions, female rainbow trout were exposed to graded concentrations of water from the River Lambro, a polluted tributary of the River Po, and to the effluent of a large wastewater treatment plant which flows into the River Lambro. In field exposures, trout were held in cages in the River Po upstream and downstream from the confluence of the River Lambro. After 10-day (laboratory) and 30-day (laboratory and field) exposures, trout were examined for several chemical, biochemical and histological endpoints. The results indicated that exposure to complex mixtures of chemicals, including estrogen receptor agonists, aryl-hydrocarbon receptor agonists, and probably antiandrogens, had occurred. Exposure altered the plasma levels of 17β-estradiol and testosterone, and some treatments also enhanced the activity of hepatic ethoxyresorufin O-deethylase. Gonadal histology showed varying levels of degenerative processes characterised by oocyte atresia, haemorrhages, melano-macrophage centres (MMCs), and oogonia proliferation. Liver histology showed less severe effects. - This study examined the progression of hormonal and gonadal alterations in female trout exposed to river water from an area known to affect resident fish species.

Immunolocalization of Schistosoma mansoni and Schistosoma haematobium antigens reacting with their Egyptian snail vectors.

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El-Dafrawy, Shadia M; Mohamed, Amira H; Hammam, Olfat A; Rabia, Ibrahim

2007-12-01

The reaction of the haemolymph and the tissue of infected intermediate hosts, Biomphalaria alexandrina and Bulinus truncatus to Schistosoma mansoni and S. haematobium antigens were investigated using the indirect immunoperoxidase technique. A new technique, Agarose cell block was used in collection of haemolymph which helped in collecting plenty of well formed cells in comparison to the ordinary one using the cytospin. Collected haemolymph and prepared tissues of uninfected and infected B. alexandria and B. truncatus were fixed and then reacted with anti-S. mansoni and anti-S. haematobium IgG polyclonal antibodies. The haemolymph and tissue of infected B. alexandrina and B. truncatus gave a positive peroxidase reaction represented by a brown colour. In haemolymph, the positive peroxidase reaction was detected mainly in the cytoplasm of the amoebocytes. In the tissue, it was detected in epithelial cells lining the tubules, male cells in the lumen of the tubules and in female oogonia cells along the periphery of the tubules. The similarity in the strength and distribution of positive reaction in B. alexandrina and B. truncates was observed as compared to control. Thus, the immunoperoxidase technique proved to be an effective indicator for the schistosome-antigen in the snails.

A unique species in Phytophthora clade 10, Phytophthora intercalaris sp. nov., recovered from stream and irrigation water in the eastern USA

Science.gov (United States)

Balci, Y.; Brazee, N. J.; Loyd, A. L.; Hong, C. X.

2016-01-01

A novel species of the genus Phytophthora was recovered during surveys of stream and nursery irrigation water in Maryland, Massachusetts, North Carolina, Virginia and West Virginia in the USA. The novel species is heterothallic, and all examined isolates were A1 mating type. It produced rare ornamented oogonia and amphigynous antheridia when paired with A2 mating type testers of Phytophthora cinnamomi and Phytophthora cryptogea. Sporangia of this novel species were non-papillate and non-caducous. Thin-walled intercalary chlamydospores were abundant in hemp seed agar and carrot agar, while they were produced only rarely in aged cultures grown in clarified V8 juice agar. Phylogenetic analyses based on sequences of the internal transcribed spacer region and the β-tubulin and mitochondrial cytochrome-c oxidase 1 (cox1) genes indicated that the novel species is phylogenetically close to Phytophthora gallica in Phytophthora clade 10. The novel species has morphological and molecular features that are distinct from those of other species in Phytophthora clade 10. It is formally described here as Phytophthora intercalaris sp. nov. Description of this unique clade-10 species is important for understanding the phylogeny and evolution of Phytophthora clade 10. PMID:26620125

Biotechnology applied to fish reproduction: tools for conservation.

Science.gov (United States)

de Siqueira-Silva, Diógenes Henrique; Saito, Taiju; Dos Santos-Silva, Amanda Pereira; da Silva Costa, Raphael; Psenicka, Martin; Yasui, George Shigueki

2018-04-29

This review discusses the new biotechnological tools that are arising and promising for conservation and enhancement of fish production, mainly regarding the endangered and the most economically important species. Two main techniques, in particular, are available to avoid extinction of endangered fish species and to improve the production of commercial species. Germ cell transplantation technology includes a number of approaches that have been studied, such as the transplantation of embryo-to-embryo blastomere, embryo-to-embryo differentiated PGC, larvae to larvae and embryo differentiated PGC, transplantation of spermatogonia from adult to larvae or between adults, and oogonia transplantation. However, the success of germ cell transplantation relies on the prior sterilization of fish, which can be performed at different stages of fish species development by means of several protocols that have been tested in order to achieve the best approach to produce a sterile fish. Among them, fish hybridization and triploidization, germline gene knockdown, hyperthermia, and chemical treatment deserve attention based on important results achieved thus far. This review currently used technologies and knowledge about surrogate technology and fish sterilization, discussing the stronger and the weaker points of each approach.

Morphological and Genetic Analyses of the Invasive Forest Pathogen Phytophthora austrocedri Reveal that Two Clonal Lineages Colonized Britain and Argentina from a Common Ancestral Population.

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Henricot, Béatrice; Pérez-Sierra, Ana; Armstrong, April C; Sharp, Paul M; Green, Sarah

2017-12-01

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15°C and all isolates were killed at 25°C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

Association of TCTP with Centrosome and Microtubules

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Mariusz K. Jaglarz

2012-01-01

Full Text Available Translationally Controlled Tumour Protein (TCTP associates with microtubules (MT, however, the details of this association are unknown. Here we analyze the relationship of TCTP with MTs and centrosomes in Xenopus laevis and mammalian cells using immunofluorescence, tagged TCTP expression and immunoelectron microscopy. We show that TCTP associates both with MTs and centrosomes at spindle poles when detected by species-specific antibodies and by Myc-XlTCTP expression in Xenopus and mammalian cells. However, when the antibodies against XlTCTP were used in mammalian cells, TCTP was detected exclusively in the centrosomes. These results suggest that a distinct pool of TCTP may be specific for, and associate with, the centrosomes. Double labelling for TCTP and γ-tubulin with immuno-gold electron microscopy in Xenopus laevis oogonia shows localization of TCTP at the periphery of the γ-tubulin-containing pericentriolar material (PCM enveloping the centriole. TCTP localizes in the close vicinity of, but not directly on the MTs in Xenopus ovary suggesting that this association requires unidentified linker proteins. Thus, we show for the first time: (1 the association of TCTP with centrosomes, (2 peripheral localization of TCTP in relation to the centriole and the γ-tubulin-containing PCM within the centrosome, and (3 the indirect association of TCTP with MTs.

The number of oogonia and somatic cells in the human female embryo and fetus in relation to whether or not exposed to maternal cigarette smoking

DEFF Research Database (Denmark)

Lutterodt, M C; Sørensen, K P; Larsen, K B

2009-01-01

of in utero exposure to cigarette smoking. METHODS: Twenty-nine human first-trimester ovaries from legal abortions [aged 38-64 days post-conception (p.c.)] were collected. Mothers filled out a questionnaire about their smoking habits and delivered a urine sample for cotinine analysis. The ovarian cell numbers...

Mutational changes of intraspecific agressiveness in the convict cichlid (Cichlasoma nigrofasciatum Guenther) after irradiation of parental spermatogonia and oogonia with different doses of X-rays

International Nuclear Information System (INIS)

Juerges, U.; Schroeder, J.H.; Sund, M.

1984-01-01

The agonistic behavior of mated convict cichlids (Cichlasoma nigrofasciatum) derived from gonial germ cells which were exposed to 0 (controls), 250, 500, 1,000, or 2,000 R of X-rays was determined by counting the attacks delivered to subadult conspecifics during the first eight days after spawning. While no day effects and no interactions with sex and radiation dose were found, males were significantly more aggressive in the treatment groups than the corresponding females. The highest aggressivness appeared in F 1 pairs derived from parental gonia irradiated with 250 R, and the lowest aggressiveness occurred in the 500-F 1 group. These two treatment groups differed significantly from each other, whereas no further significant differences could be detected. F 1 males derived from gonial X-irradiation with 750 R could not be mated successfully because they killed their own females. The changes of male aggressiveness reflect reversely the previously published results of changes in social cohesiveness of the individual cichlid fish. (author)

[An ultrastructural study of oogenesis in the planarian Schmidtea mediterranea (Platyhelminthe, Paludicola)].

Science.gov (United States)

Harrath, Abdul Halim; Alwasal, Saleh H; Alhazza, Ibrahim; Zghal, Fathia; Tekaya, Saida

2011-07-01

The ovary of the freshwater planarian Schmidtea mediterranea has been studied for the first time using both light and electron microscopy methods. The ultrastructure of the ovary revealed two types of cells: accessory cells and germinal cells at various stages of differentiation, distributed along a maturation axis. Initially, oogonia underwent cytoplasm growth due to the development of organelles, such as endoplasmic reticulum, Golgi complex, and mitochondria, which are all involved in the production of cytoplasmic inclusions or yolk globules. It is shown that the chromatoid body and fibrogranular aggregates may participate in the synthesis of vitelline inclusions. When completely mature, the oocytes have become larger, due to the accumulation of nutritive inclusions, which are round in shape and have a paracrystalline structure. These inclusions are interpreted as being yolk globules and may represent a kind of nutritive material for the developing embryo. These ultrastructural features of the ovary agree with the available phylogenetic tree, based on morphological and karyological characters that considers Schmidtea group as a genus and not a subgenus. The presence of sperm between the oocytes suggests that fertilization may occur within the ovary, representing an uncommon condition within the Triclads, in which fertilization usually takes places outside of the ovaries. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

A stockpile of ova in the grass frog Rana temporaria is established once for the life span. Do ovaries in amphibians and in mammals follow the same evolutionary strategy?

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Ogielska, Maria; Kotusz, Agnieszka; Augustyńska, Renata; Ihnatowicz, Jerzy; Paśko, Łukasz

2013-04-01

Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a female. Our quantitative studies show that primary oogonia in adult female frogs can proliferate, but they fail to differentiate further and do not enter meiosis, and thereby there is no supplementation of new generations of oocytes after each spawning. Ovaries of one-year-old grass frogs contain (median) 53,447 diplotene oocytes, in two-years-old frogs this number decreased to 33,583 and eventually reached 25,679 in virgin mature females. More than 50% decrease in the total oocyte number was accompanied by massive degeneration (atresia) of oocytes. The final number of oocytes in a female forms a stock for 11-12 breeding seasons and exceeds the number of eggs produced during the potential reproductive life span of this species. The phylogenetic context of oocyte recruitment modes in the major clades of vertebrates is discussed in respect to their ability to replenish the stock (a renewable stock in ovaries named "open" vs. a non-renewable stock in ovaries named "closed"). Copyright © 2013 Wiley Periodicals, Inc.

Endocrine function and reproductive impairment in an irradiated population of the lizard Uta stansburiana

International Nuclear Information System (INIS)

Pearson, A.K.; Licht, P.; Nagy, K.A.; Medica, P.A.

1978-01-01

Gonadal changes in lizards (Uta stansburiana) exposed to chronic low levels of γ radiation (1.5 to 10 R/day) under field conditions are described, and attempts to evaluate endocrine involvement in these changes are made. Reproductive impairment in irradiated males was demonstrated during the breeding season by reduced testes weights and by seminiferous tubules devoid of germ cells. Ultrastructural morphology of Leydig cells, plasma testosterone levels, and developed accessory sex structures indicatedd normal steroidogenesis in such males; cytology of the pituitary gonadotropes and pituitary gonadotropin content indicated normal gonadotropin levels. These findings suggest that low levels of radiation affect the spermatogenic process directly, rather than through damage to the pituitary. Comparable irradiation caused complete resorption of ovarian tissue in some female Uta. The oviducts were atrophic and the pituitary gonadotropes hyperactive. Resemblance of gonadotropes to those of castrated animals and reduced pituitary hormone content suggests elevated levels of gonadotropin production, probably due to the absence of ovarian steroid feedback in affected animals. The continued mitotic activity of oogonia in adult reptiles and their limited number contributed to the vulnerability of germinal tissue in irradiated female lizards. Destruction of the germ cells was accompanied by resorption of all ovarian tissue including steroidogenic elements. Thus, in females as in males, radiation appears to damage gametogenesis rather than pituitary function

Gonadoblastoma: evidence for a stepwise progression to dysgerminoma in a dysgenetic ovary.

Science.gov (United States)

Pauls, Katharina; Franke, Folker E; Büttner, Reinhard; Zhou, Hui

2005-09-01

Gonadoblastomas are neoplasms of dysgenetic gonads which may undergo regression or become overgrown by malignant germ cell tumors (mGCTs). Since little is known about their relationship to normal gonadal development and mGCTs, we studied the phenotype and antigenic profile of gonadoblastomas in comparison with adjacent dysgerminomas and fetal gonads. Three cases of gonadoblastomas and fetal gonads of both sexes were analyzed using oncofetal markers to M2A-antigen (M2A), germ cell alkaline phosphatase (PLAP/GCAP), receptor tyrosine kinase c-kit (c-kit), and somatic angiotensin converting enzyme (sACE) as well as the proliferation marker MIB-1. Morphologically, microfollicular pattern of gonadoblastomas showed a fetal germ cell organization reminiscent of oocytic clusters of fetal ovaries. They contained both cell types, similar to oocytes (M2A-, GCAP-, c-kit+/-, sACE-) and oogonia (M2A+, GCAP+, c-kit+, sACE+). The percentage of germ cells immunoreactive for oncofetal markers and the proliferation index increased from microfollicular over coronary patterns to adjacent dysgerminomas. Supportive cells of gonadoblastomas showed a uniform phenotype (CK18+, vimentin+, sACE+, alpha-inhibin+, M2A-) but in contrast to fetal germ cells lacked a clear equivalence to fetal tissues. Our results show that gonadoblastomas mimic female fetal ovary and exhibit a stepwise progression from follicular pattern to coronary pattern and finally to dysgerminomas.

Species from within the Phytophthora cryptogea complex and related species, P. erythroseptica and P. sansomeana, readily hybridize.

Science.gov (United States)

Safaiefarahani, Banafsheh; Mostowfizadeh-Ghalamfarsa, Reza; Hardy, Giles E St J; Burgess, Treena I

2016-08-01

During a study on the phylogenetic relationships between species in the Phytophthora cryptogea complex and related species, Phytophthora erythroseptica and Phytophthora sansomeana, 19 hybrid isolates with multiple polymorphisms in the nuclear sequences were observed. Molecular characterization of hybrids was achieved by sequencing three nuclear (internal transcribed spacers, β-tubulin (TUB), heat shock protein 90) and two mitochondrial (cytochrome c oxidase subunit I (coxI), NADH dehydrogenase subunit I (NADH)) gene regions and cloning of the single-copy nuclear gene, TUB. Based on the molecular studies the hybrid isolates belonged to six distinct groups between P. cryptogea, P. erythroseptica, Phytophthora pseudocryptogea, P. sansomeana, and Phytophthora sp. kelmania. In all cases, only a single coxI and NADH allele was detected and nuclear genes were biparentally inherited, suggesting that the hybrids arose from sexual recombination events. Colony morphology, growth rate, cardinal temperatures, breeding system, and morphology of sporangia, oogonia, oospores, and antheridia were also determined. Some morphological differences between the hybrids and the parental species were noted; however, they were not sufficient to reliably distinguish the taxa and DNA markers from nuclear and mitochondrial genes will to be necessary for their identification. The parental species are all important pathogens of agricultural fields that have been transported globally. With the apparent ease of hybridization within this group there is ample opportunity for virulent hybrids to form, perhaps with extended host ranges. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Observaciones sobre algunos caracteres de valor taxonómico en el grupo de los carófitos

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Pedrola, J.

1990-05-01

Full Text Available The variability of the microstructurals characters and mineralogical composition of the oogonia of some charophytes extant and fossils is described. Two types of microstructures (W & V are find. These are conservative into populations and are not able to change by the environmental factors. Moreover, these structures are quite constant in some of the phylogenetics groups studied. Consequently it is proposed its utilization in taxonomy. The apparition of original compounds in the Charophyta (vaterite. whewelite, aragonite, etc. is important because it supports an old idea that considerates the Charophyta as an autonomous class between the Clorophyta and the Traqueophyta.

Se describe la variabilidad de los caracteres microestructurales y la composición mineralógica de las células espirales del oogonio en diversas especies actuales y fósiles del grupo de los carófitos. Se encuentran así, dos tipos de microestructuras diferentes (W y V que se muestran conservativas en el seno de las poblaciones, no moldeables por el ambiente y relativamente constantes dentro de los distintos grupos filogenéticos. En consecuencia, se propone su utilización con fines taxonómicos. La aparición de ciertos elementos mineralógicos (vaterita, whewelita, aragonito etc. resulta remarcable por su originalidad y su apoyo al viejo criterio que consideraba los carófitos como una clase autónoma y quizás de "enlace" entre clorófitos y traqueófitos.

Oogenesis, follicular development and reproductive performance in the prenatally irradiated bovine

International Nuclear Information System (INIS)

Erickson, B.H.; Reynolds, R.A.

1978-01-01

To determine the radioresponse of the various developmental stages of the prenatal bovine germ cell, cows bearing foetuses varying in age from 40+-5 (point of gonadal sex differentiation) to 270+-10 (approximately 13 days before parturition) days of gestation were irradiated with 300 R of 60 Co gamma radiation at 25-50 R/min, a level just below that likely to cause maternal deaths and gross foetal abnormalities at some developmental stages. Dose to the foetal gonad was approximately 100 rad. When the prenatally irradiated heifers were approximately 10 months old their ovaries were recovered at slaughter, serially sectioned, and prepared for microscopic analysis. A complete quantitative analysis of oocytes in primordial, growing and vesicular follicles was effected. Follicular development (reflected by counts of growing and vesicular follicles) was apparently unaffected at all ages tested (P>0.25), whereas oogenesis (reflected by counts of oocytes in primordial follicles) was significantly impeded (64% of control) only between 70 and 90 days of gestation (P<0.05). The germ-cell population at this period differs from later developmental stages principally by the presence of a high proportion of mitotically active oogonia, hence it appears that the oogonium is the most vulnerable cell type. Neither the viability nor reproductive performance of 60 cows that were prenatally irradiated (100 rad) at either 80+-10 or 130+-20 days of gestation was affected through a minimum of 5 years of postnatal life and three pregnancies. (author)

Oocyte-like cells induced from mouse spermatogonial stem cells.

Science.gov (United States)

Wang, Lu; Cao, Jinping; Ji, Ping; Zhang, Di; Ma, Lianghong; Dym, Martin; Yu, Zhuo; Feng, Lixin

2012-08-06

During normal development primordial germ cells (PGCs) derived from the epiblast are the precursors of spermatogonia and oogonia. In culture, PGCs can be induced to dedifferentiate to pluripotent embryonic germ (EG) cells in the presence of various growth factors. Several recent studies have now demonstrated that spermatogonial stem cells (SSCs) can also revert back to pluripotency as embryonic stem (ES)-like cells under certain culture conditions. However, the potential dedifferentiation of SSCs into PGCs or the potential generation of oocytes from SSCs has not been demonstrated before. We report that mouse male SSCs can be converted into oocyte-like cells in culture. These SSCs-derived oocytes (SSC-Oocs) were similar in size to normal mouse mature oocytes. They expressed oocyte-specific markers and gave rise to embryos through parthenogenesis. Interestingly, the Y- and X-linked testis-specific genes in these SSC-Oocs were significantly down-regulated or turned off, while oocyte-specific X-linked genes were activated. The gene expression profile appeared to switch to that of the oocyte across the X chromosome. Furthermore, these oocyte-like cells lost paternal imprinting but acquired maternal imprinting. Our data demonstrate that SSCs might maintain the potential to be reprogrammed into oocytes with corresponding epigenetic reversals. This study provides not only further evidence for the remarkable plasticity of SSCs but also a potential system for dissecting molecular and epigenetic regulations in germ cell fate determination and imprinting establishment during gametogenesis.

Oocyte-like cells induced from mouse spermatogonial stem cells

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Wang Lu

2012-08-01

Full Text Available Abstract Background During normal development primordial germ cells (PGCs derived from the epiblast are the precursors of spermatogonia and oogonia. In culture, PGCs can be induced to dedifferentiate to pluripotent embryonic germ (EG cells in the presence of various growth factors. Several recent studies have now demonstrated that spermatogonial stem cells (SSCs can also revert back to pluripotency as embryonic stem (ES-like cells under certain culture conditions. However, the potential dedifferentiation of SSCs into PGCs or the potential generation of oocytes from SSCs has not been demonstrated before. Results We report that mouse male SSCs can be converted into oocyte-like cells in culture. These SSCs-derived oocytes (SSC-Oocs were similar in size to normal mouse mature oocytes. They expressed oocyte-specific markers and gave rise to embryos through parthenogenesis. Interestingly, the Y- and X-linked testis-specific genes in these SSC-Oocs were significantly down-regulated or turned off, while oocyte-specific X-linked genes were activated. The gene expression profile appeared to switch to that of the oocyte across the X chromosome. Furthermore, these oocyte-like cells lost paternal imprinting but acquired maternal imprinting. Conclusions Our data demonstrate that SSCs might maintain the potential to be reprogrammed into oocytes with corresponding epigenetic reversals. This study provides not only further evidence for the remarkable plasticity of SSCs but also a potential system for dissecting molecular and epigenetic regulations in germ cell fate determination and imprinting establishment during gametogenesis.

Descripción histológica y caracterización de los estados de madurez gonadal de hembras de Cryphiops caementarius (Molina, 1782 (Decapoda: Palaemonidae Histological description and characterization of the ovarian cycle of Cryphiops caementarius (Molina, 1782 (Decapoda: Palaemonidae

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Jorge E Moreno

2012-09-01

commercial freshwater Palemonid present in Chilean inland waters. Even though this situation has awakened interest in studies which allow its controlled reproduction in captivity, currently little is known regarding basic reproductive aspects of this species. Given its relevance, this work describes and characterizes the whole ovarian cycle of Cryphiops caementarius, based on changes in external and internal ovarian morphology. Adult C. caementarius females, obtained from Limarí River, were dissected and its ovaries removed and prepared for histological examinations. Fibromuscular tissue divides the ovarian tissue of each lobe into cone-shaped ovarian pouches (Maturation cones, each one containing various steps of oocytes according to the stages of ovarian development. Based on light microscopic observations of cells' sizes, morphology, and staining with H-E, the female germ cells could be classified into six different types, which include oogonia (Ov, early previtellogenic oocytes (O1, late previtellogenic oocytes (O2, early vitellogenic oocytes (O3, late vitellogenic oocytes (O4 and mature oocytes (OM. The ovarian cycle is divided into five stages based on the amount and types of oocytes present in each stage. Stage 0 and I are spawned and previtellogenesis stages. Stage II and III are early and intermediate vitellogenesis stages, while stage IV is maturity advanced stage. The presence of oogonia and previtellogenic oocytes among fully mature oocytes in stage IV reflect the capacity of the ovary of C. caementarius females to start a new full maturity cycle in a short time period.

Light and electron microscopic analyses of Vasa expression in adult germ cells of the fish medaka.

Science.gov (United States)

Yuan, Yongming; Li, Mingyou; Hong, Yunhan

2014-07-15

Germ cells of diverse animal species have a unique membrane-less organelle called germ plasm (GP). GP is usually associated with mitochondria and contains RNA binding proteins and mRNAs of germ genes such as vasa. GP has been described as the mitochondrial cloud (MC), intermitochondrial cement (IC) and chromatoid body (CB). The mechanism underlying varying GP structures has remained incompletely understood. Here we report the analysis of GP through light and electron microscopy by using Vasa as a marker in adult male germ cells of the fish medaka (Oryzias latipes). Immunofluorescence light microscopy revealed germ cell-specific Vasa expression. Vasa is the most abundant in mitotic germ cells (oogonia and spermatogonia) and reduced in meiotic germ cells. Vasa in round spermatids exist as a spherical structure reminiscent of CB. Nanogold immunoelectron microscopy revealed subcellular Vasa redistribution in male germ cells. Vasa in spermatogonia concentrates in small areas of the cytoplasm and is surrounded by mitochondria, which is reminiscent of MC. Vasa is intermixed with mitochondria to form IC in primary spermatocytes, appears as the free cement (FC) via separation from mitochondria in secondary spermatocyte and becomes condensed in CB at the caudal pole of round spermatids. During spermatid morphogenesis, Vasa redistributes and forms a second CB that is a ring-like structure surrounding the dense fiber of the flagellum in the midpiece. These structures resemble those described for GP in various species. Thus, Vasa identifies GP and adopts varying structures via dynamic reorganization at different stages of germ cell development. Copyright © 2014 Elsevier B.V. All rights reserved.

Transcription factors SOHLH1 and SOHLH2 coordinate oocyte differentiation without affecting meiosis I.

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Shin, Yong-Hyun; Ren, Yu; Suzuki, Hitomi; Golnoski, Kayla J; Ahn, Hyo Won; Mico, Vasil; Rajkovic, Aleksandar

2017-06-01

Following migration of primordial germ cells to the genital ridge, oogonia undergo several rounds of mitotic division and enter meiosis at approximately E13.5. Most oocytes arrest in the dictyate (diplotene) stage of meiosis circa E18.5. The genes necessary to drive oocyte differentiation in parallel with meiosis are unknown. Here, we have investigated whether expression of spermatogenesis and oogenesis bHLH transcription factor 1 (Sohlh1) and Sohlh2 coordinates oocyte differentiation within the embryonic ovary. We found that SOHLH2 protein was expressed in the mouse germline as early as E12.5 and preceded SOHLH1 protein expression, which occurred circa E15.5. SOHLH1 protein appearance at E15.5 correlated with SOHLH2 translocation from the cytoplasm into the nucleus and was dependent on SOHLH1 expression. NOBOX oogenesis homeobox (NOBOX) and LIM homeobox protein 8 (LHX8), two important regulators of postnatal oogenesis, were coexpressed with SOHLH1. Single deficiency of Sohlh1 or Sohlh2 disrupted the expression of LHX8 and NOBOX in the embryonic gonad without affecting meiosis. Sohlh1-KO infertility was rescued by conditional expression of the Sohlh1 transgene after the onset of meiosis. However, Sohlh1 or Sohlh2 transgene expression could not rescue Sohlh2-KO infertility due to a lack of Sohlh1 or Sohlh2 expression in rescued mice. Our results indicate that Sohlh1 and Sohlh2 are essential regulators of oocyte differentiation but do not affect meiosis I.

Sex reversal in zebrafish fancl mutants is caused by Tp53-mediated germ cell apoptosis.

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Adriana Rodríguez-Marí

2010-07-01

Full Text Available The molecular genetic mechanisms of sex determination are not known for most vertebrates, including zebrafish. We identified a mutation in the zebrafish fancl gene that causes homozygous mutants to develop as fertile males due to female-to-male sex reversal. Fancl is a member of the Fanconi Anemia/BRCA DNA repair pathway. Experiments showed that zebrafish fancl was expressed in developing germ cells in bipotential gonads at the critical time of sexual fate determination. Caspase-3 immunoassays revealed increased germ cell apoptosis in fancl mutants that compromised oocyte survival. In the absence of oocytes surviving through meiosis, somatic cells of mutant gonads did not maintain expression of the ovary gene cyp19a1a and did not down-regulate expression of the early testis gene amh; consequently, gonads masculinized and became testes. Remarkably, results showed that the introduction of a tp53 (p53 mutation into fancl mutants rescued the sex-reversal phenotype by reducing germ cell apoptosis and, thus, allowed fancl mutants to become fertile females. Our results show that Fancl function is not essential for spermatogonia and oogonia to become sperm or mature oocytes, but instead suggest that Fancl function is involved in the survival of developing oocytes through meiosis. This work reveals that Tp53-mediated germ cell apoptosis induces sex reversal after the mutation of a DNA-repair pathway gene by compromising the survival of oocytes and suggests the existence of an oocyte-derived signal that biases gonad fate towards the female developmental pathway and thereby controls zebrafish sex determination.

Migration and differentiation potential of stem cells in the cnidarian Hydractinia analysed in eGFP-transgenic animals and chimeras.

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Künzel, Timo; Heiermann, Reinhard; Frank, Uri; Müller, Werner; Tilmann, Wido; Bause, Markus; Nonn, Anja; Helling, Matthias; Schwarz, Ryan S; Plickert, Günter

2010-12-01

To analyse cell migration and the differentiation potential of migratory stem cells in Hydractinia, we generated animals with an eGFP reporter gene stably expressed and transmitted via the germline. The transgene was placed under the control of two different actin promoters and the promoter of elongation factor-1α. One actin promoter (Act-II) and the EF-1α promoter enabled expression of the transgene in all cells, the other actin promoter (Act-I) in epithelial and gametogenic cells, but not in the pluripotent migratory stem cells. We produced chimeric animals consisting of histocompatible wild type and transgenic parts. When the transgene was under the control of the epithelial cell specific actin-I promoter, non-fluorescent transgenic stem cells immigrated into wild type tissue, stopped migration and differentiated into epithelial cells which then commenced eGFP-expression. Migratory stem cells are therefore pluripotent and can give rise not only to germ cells, nematocytes and nerve cells, but also to epithelial cells. While in somatic cells expression of the act-I promoter was restricted to epithelial cells it became also active in gametogenesis. The act-I gene is expressed in spermatogonia, oogonia and oocytes. In males the expression pattern showed that migratory stem cells are the precursors of both the spermatogonia and their somatic envelopes. Comparative expression studies using the promoters of the actin-II gene and the elongation factor-1α gene revealed the potential of transgenic techniques to trace the development of the nervous system. Copyright © 2010 Elsevier Inc. All rights reserved.

Fasciola hepatica: a light and electron microscope study of the ovary and of the development of oocytes within eggs in the uterus provides an insight into reproductive strategy.

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Hanna, R E B; Moffett, D; Forster, F I; Trudgett, A G; Brennan, G P; Fairweather, I

2016-05-15

The ultrastructure of the ovary of Fasciola hepatica collected from field-infected sheep, was compared with that of flukes from laboratory-infected rats harbouring the Oberon or the Cullompton fluke isolate. At the periphery of the ovarian tubules, in all flukes, interstitial tissue was identified that appears to provide physical support and facilitate the metabolism of the germinal-line cells. Oogonia undergo mitotic division to maintain the cell population and to produce oocytes. Early oocytes feature conspicuous synaptonemal complexes in the nucleoplasm, and these become less evident as the oocytes grow in size, move towards the core of the ovarian tubule, and synthesise osmiophilic bodies. The latter may represent cortical granules, and serve to block polyspermy. The identity of the synaptonemal complexes was confirmed by immunocytochemical labelling of synaptonemal proteins. The occurrence of synaptonemal complexes in the oocytes of all fluke types examined indicates that pairing of bivalent chromosomes, with the potential for genetic recombination and chiasmata formation, is a feature of the triploid aspermic parthenogenetic Cullompton flukes, as well as of the wild-type out-breeding field-derived and Oberon isolate flukes. In oocytes within shelled eggs in the proximal uterus of all flukes, condensed chromosomes align at meiotic metaphase plates. Following the reduction division, two equal pronuclei appear in each oocyte in the distal uterus. On the basis of these observations, a mechanism of facultative parthenogenesis for F. hepatica is proposed that accommodates the survival and clonal expansion of triploid aspermic isolates. Copyright © 2016 Elsevier B.V. All rights reserved.

Radiation-induced mutations in fish

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Schroeder, J.H.

1980-01-01

X-ray-induced mutations in teleostean fish were studied from the point of social behavior. A significant reduction in male aggression was found in the postirradiated F 1 generation after the irradiation of parental oogonia and spermatogonia, with 2 x 500 R (24 hr apart) of x-rays, but did not alter the aggression of F 1 females. A study on backcross generation of irradiated line fitted with a two-factor model of dominant genetic factors, high- and low-aggressive, which co-acted additively in repressing the male aggression. Social cohesiveness was compared between F 1 convict cichlides (C. nigrofasciatum) exposed by 0, 250, 500, 750, 1000, and 2000 R of x-rays. The best response was observed in males with 500 R and in females with 750 R. While an increase in cohesiveness was observed in F 1 males with 500 R, the cohesiveness of F 1 females decreased with 750 and 200 R, suggesting that the increase in male was associated with a reduction of inter-male aggression. A new ''guppy male courtship activity test'' was carried out in the offsprings of irradiated guppy, maintained in seawater and in freshwater. The mean values of both the frequency and the duration of four behavioral traits of the male guppy increased in postirradiated F 1 generation of the seawater substrain but were unchanged in that of freshwater's. In F 2 generation the mean values of the same behavioral characters decreased in both seawater and freshwater substrains. (Nakanishi, T.)

Annual gametogenesis and reproductive effort of the limpet Cellana grata (Gould, 1859) (Gastropoda: Nacellidae) in a rocky intertidal beach at Ulleungdo Island off the east coast of Korea

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Yang, Hyun-Sung; Kang, Do-Hyung; Park, Heung-Sik; Choi, Kwang-Sik

2017-12-01

Widely distributed from the northern coast of Vietnam to the northern Japan, the limpet Cellana grata (Gould, 1859) occurs commonly on the south and east coasts of Korea. Despite their wide distribution range, few studies have investigated the annual gametogenesis and reproductive effort of C. grata. In an attempt to understand the reproductive physiology of the limpet, we investigated the annual gametogenesis and reproductive effort of C. grata from Ulleungdo Island off the east coast of Korea. Histology revealed that the gonial mitosis commenced in January, as the female exhibited small oogonia (10-40 μm) in the follicle. From March to June, the oocyte size increased dramatically, and fully mature eggs (110-170 μm in diameter) appeared in early summer. First spawning males and females were observed in July, as the surface seawater temperature (SST) reached 22.1°C. The spawning male and females could be observed until the end of December. Gonad somatic index (GSI), a ratio of gonad mass to the total tissue weight, of the male ranged from 0.6 (April) to 17.9 (July), while the female GSI varied from 1.0 (February) to 18.3 (July). GSI of male and female declined rapidly from July to August, suggesting that the major purse of the spawning at the study site was between July and August. Our study suggested that the commercial catch of C. grata during July and August must be suspended at Ulleungdo Island, in order to protect the spawning limpets, which enhances C. grata recruitment and the population.

The Dr-nanos gene is essential for germ cell specification in the planarian Dugesia ryukyuensis.

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Nakagawa, Haruka; Ishizu, Hirotsugu; Chinone, Ayako; Kobayashi, Kazuya; Matsumoto, Midori

2012-01-01

Homologs of nanos are required for the formation and maintenance of germline stem cell (GSC) systems and for gametogenesis in many metazoans. Planarians can change their reproductive mode seasonally, alternating between asexual and sexual reproduction; they develop and maintain their somatic stem cells (SSCs) and GCSs from pluripotent stem cells known as neoblasts. We isolated a nanos homolog, Dr-nanos, from the expressed sequence tags (ESTs) of the sexualized form of Dugesia ryukyuensis. We examined the expression of Dr-nanos in asexual and sexualized planarians by in situ hybridization and analyzed its function using RNA interference (RNAi) together with a planarian sexualization assay. A nanos homolog, Dr-nanos, was identified in the planarian D. ryukyuensis. Dr-nanos expression was observed in the ovarian primordial cells of the asexual worms. This expression increased in proportion to sexualization and was localized in the early germline cells of the ovaries and testes. In X-ray-irradiated worms, the expression of Dr-nanos decreased to a large extent, indicating that Dr-nanos is expressed in some subpopulations of stem cells, especially in GSCs. During the sexualization process, worms in which Dr-nanos was knocked down by RNAi exhibited decreased numbers of oogonia in the ovaries and failed to develop testes, whereas the somatic sexual organs were not affected. We conclude that Dr-nanos is essential for the development of germ cells in the ovaries and testes and may have a function in the early stages of germ cell specification, but not in the development of somatic sexual organs.

Molecular characterization of sdf1 and cxcr4 in the Mozambique tilapia, Oreochromis mossambicus.

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Amat-Fernandez, Jorge; Hammond, Michael J; Liang, Di; Wang, Tianfang; Ventura, Tomer; Elizur, Abigail; Cummins, Scott F

2017-01-01

Animal sexual reproduction relies on primordial germ cells (PGCs), the predecessors of the germ cell lineage, giving rise to either spermatogonia or oogonia after the completion of gonadal differentiation. There is limited information on the mechanism of PGC migration leading to the formation of the primordial gonad in Perciform fish. Oreochromis mossambicus, a tilapiine species, was investigated that is a commercially important aquaculture species in many parts of the world while in other areas it has become an invasive pest. Key components involved in PGC migration were identified, including the stromal-cell derived factor 1 (Om-sdf1a, Om-sdf1b) and the CXC receptor 4 (Om-cxcr4): both share conservation with existing model species. The spatial gene expression profiles were determined through transcript and protein analysis and displayed distinct localisation within the region of the developing gonad in larvae and within the adult gonads of certain cell populations. A recombinant Om-sdf1a was produced in Escherichia coli that activates Om-cxcr4 using a BRET-based yeast in vitro assay system, suggesting that it is structurally similar to the native Om-sdf1a and is appropriate for further structural studies. This study has improved understanding of the molecular basis of tilapia reproduction through investigation of gonad development, which may be important in the progression towards reproductive suppression methods to control tilapia populations in the wild. In addition, this research will facilitate developments in germ cell transplantation, an innovative technique that harnesses germ cell migration and allows the uptake of foreign germ cells, which differentiate to produce sperm or ova. Copyright © 2016 Elsevier B.V. All rights reserved.

Cellular and molecular effect of MEHP Involving LXRα in human fetal testis and ovary.

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Muczynski, Vincent; Lecureuil, Charlotte; Messiaen, Sébastien; Guerquin, Marie-Justine; N'tumba-Byn, Thierry; Moison, Delphine; Hodroj, Wassim; Benjelloun, Hinde; Baijer, Jan; Livera, Gabriel; Frydman, René; Benachi, Alexandra; Habert, René; Rouiller-Fabre, Virginie

2012-01-01

Phthalates have been shown to have reprotoxic effects in rodents and human during fetal life. Previous studies indicate that some members of the nuclear receptor (NR) superfamilly potentially mediate phthalate effects. This study aimed to assess if expression of these nuclear receptors are modulated in the response to MEHP exposure on the human fetal gonads in vitro. Testes and ovaries from 7 to 12 gestational weeks human fetuses were exposed to 10(-4)M MEHP for 72 h in vitro. Transcriptional level of NRs and of downstream genes was then investigated using TLDA (TaqMan Low Density Array) and qPCR approaches. To determine whether somatic or germ cells of the testis are involved in the response to MEHP exposure, we developed a highly efficient cytometric germ cell sorting approach. In vitro exposure of fetal testes and ovaries to MEHP up-regulated the expression of LXRα, SREBP members and of downstream genes involved in the lipid and cholesterol synthesis in the whole gonad. In sorted testicular cells, this effect is only observable in somatic cells but not in the gonocytes. Moreover, the germ cell loss induced by MEHP exposure, that we previously described, is restricted to the male gonad as oogonia density is not affected in vitro. We evidenced for the first time that phthalate increases the levels of mRNA for LXRα, and SREBP members potentially deregulating lipids/cholesterol synthesis in human fetal gonads. Interestingly, this novel effect is observable in both male and female whereas the germ cell apoptosis is restricted to the male gonad. Furthermore, we presented here a novel and potentially very useful flow cytometric cell sorting method to analyse molecular changes in germ cells versus somatic cells.

Cellular and molecular effect of MEHP Involving LXRα in human fetal testis and ovary.

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Vincent Muczynski

Full Text Available Phthalates have been shown to have reprotoxic effects in rodents and human during fetal life. Previous studies indicate that some members of the nuclear receptor (NR superfamilly potentially mediate phthalate effects. This study aimed to assess if expression of these nuclear receptors are modulated in the response to MEHP exposure on the human fetal gonads in vitro.Testes and ovaries from 7 to 12 gestational weeks human fetuses were exposed to 10(-4M MEHP for 72 h in vitro. Transcriptional level of NRs and of downstream genes was then investigated using TLDA (TaqMan Low Density Array and qPCR approaches. To determine whether somatic or germ cells of the testis are involved in the response to MEHP exposure, we developed a highly efficient cytometric germ cell sorting approach. In vitro exposure of fetal testes and ovaries to MEHP up-regulated the expression of LXRα, SREBP members and of downstream genes involved in the lipid and cholesterol synthesis in the whole gonad. In sorted testicular cells, this effect is only observable in somatic cells but not in the gonocytes. Moreover, the germ cell loss induced by MEHP exposure, that we previously described, is restricted to the male gonad as oogonia density is not affected in vitro.We evidenced for the first time that phthalate increases the levels of mRNA for LXRα, and SREBP members potentially deregulating lipids/cholesterol synthesis in human fetal gonads. Interestingly, this novel effect is observable in both male and female whereas the germ cell apoptosis is restricted to the male gonad. Furthermore, we presented here a novel and potentially very useful flow cytometric cell sorting method to analyse molecular changes in germ cells versus somatic cells.

[Structure and ultrastructure of the ovary of Cichlasoma urophthalmus (Osteichthyes: Cichlidae)].

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Viedma, Rubí; Franco, Jonathan; Bedia, Carlos; Guedea Fernández, Guadalupe; Villa Zevallos, Héctor Barrera; Barrera Escorcia, Héctor

2011-06-01

The study of the normal development, differentiation, structure and function of various components of developing follicles in the ovaries of numerous fish species have been a consistent focus of comparative reproduction. The structural and ultrastructural features of gonads from Cichlasoma urophthalmus have received scarce attention. In this work, we realized a descriptive study of female gonads of Cichlasoma urophthalmus. A total of 40 samples were collected in the Veracruz Alvarado Lagoon, Mexico in 2007-2008 period including the windy, dry and rainy seasons. Female gonads were extracted and a portion was fixed in 4% formaldehyde for treatment for routine histology hematoxylin and eosin (HE) and another part was processed for transmission electron microscopy (TEM). The gonads were fixed in 3% glutaraldehyde and 2% osmium tetroxide, followed by dehydrated in ethanol 50%, 70%, 80%, 95% and 100% for inclusion in Epon, thin sections were then prepared and were contrasted with lead citrate and uranyl acetate. The process of oocyte development can be divided into five distinct stages (formation of oocytes from oogonia, primary growth, lipid stage, vitellogenesis and maturation). In this work, we found that the primary growth stage is characterized by intense RNA synthesis and the differentiation of the vitelline envelope. Secondary growth starts with the accumulation of lipid droplets in the oocyte cytoplasm (lipid stage), which is then followed by massive uptake and processing of proteins into yolk platelets (vitellogenic stage). During the maturation stage, the lipid inclusions coalesce into a single oil droplet, and hydrolysis of the yolk platelets leads to the formation of a homogeneous mass of fluid yolk in mature eggs. In conclusion, further studies should elucidate structure and ultrastructural changes in the ovarian follicular components, in C. urophthalmus during different stages of oocyte growth.

Localization of early germ cells in a stony coral, Euphyllia ancora: potential implications for a germline stem cell system in coral gametogenesis

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Shikina, Shinya; Chung, Yi-Jou; Wang, Hsiang-Ming; Chiu, Yi-Ling; Shao, Zih-Fang; Lee, Yan-Horn; Chang, Ching-Fong

2015-06-01

Most corals exhibit annual or multiple gametogenic cycles. Thus far, coral gametogenesis has been studied in many species and locations during the past three decades; however, currently, only a few papers exist that describe the origin of germ cells, such as germline stem cells (GSCs), which support the continuous production of gametes in every reproductive cycle. To address this issue, in this study, we focused on and identified piwi gene, which has been used as a marker of germline cells, including GSCs, in various metazoans, in a scleractinian coral, Euphyllia ancora. Reverse-transcription PCR and Western blotting analyses revealed that E. ancora piwi-like ( Eapiwi) is expressed in mesentery tissues where the sites of gametogenesis are located for both sexes. Immunohistochemistry with a specific antibody against Eapiwi revealed strong immunoreactivity in the spermatogonia in males and in the oogonia and early oocytes in females, demonstrating that Eapiwi could be used as an early germ cell marker in E. ancora. Subsequent immunohistochemical analyses regarding the spatial and temporal distribution patterns of early germ cells in mesentery tissues revealed that early germ cells were present throughout the year in the mesentery tissue we examined, regardless of the sexual reproductive cycle. In particular, small numbers of early germ cells were observed in specific sites of mesentery tissues with fully matured gonads in both sexes. These early germ cells were not released together with mature gametes during the spawning period and remained in the mesentery tissues. These results suggested that these early germ cells most likely serve as a reservoir of germline cells and that some of these cells would produce differentiated germ cells for the upcoming sexual reproduction period; hence, these cells would function as GSCs. Our data provide new information for understanding continuous gamete production in corals.

Disruption of egg production by triclabendazole-resistant Fasciola hepatica following treatment with a commercial preparation of myrrh (Mirazid).

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Abdelaal, Mohamed M O; Brennan, Gerard P; Hanna, Robert E B; Abdel-Aziz, Ahmed; Fairweather, Ian

2017-06-01

An in vitro study has been carried out to monitor changes to the female reproductive system in adult triclabendazole (TCBZ)-resistant Fasciola hepatica following treatment with a commercial preparation of myrrh ("Mirazid"). Flukes were immersed for 6 h and 24 h in myrrh extract at a concentration of 200 µg/ml, then processed for histological and transmission electron microscope (TEM) examination of the uterus, Mehlis' gland, ovary and vitellaria. Egg production had become abnormal at 6 h post-treatment (pt), with the uterine lumen being filled with free vitelline cells and masses of shell protein material; few eggs were present. At 24 h pt, no eggs were present. Distinct changes to the ovary and Mehlis' gland were only observed after 24 h incubation in Mirazid. The ovary contained numbers of apoptotic oogonia and oocytes. In the Mehlis' gland, the S1 cells were disorganised and the processes from them were vacuolated, although the disruption was not significant. More severe changes were observed in the vitelline cells and follicles. After 6 h incubation in Mirazid, although the gross organisation of the vitelline follicles appeared to be normal, nuclear changes indicative of the early stages of apoptosis were observed in the stem cells and shell protein production by the mature cells had decreased. At 24 h pt, a distinct shift in cell population was evident, with the follicles containing mainly mature cells and spaces were present between the cells. The shell globule clusters in the mature cells were disorganised. In more severely-affected follicles, cells were seen to be breaking down, with karyolytic nuclei and disintegrating cytoplasm. Overall, the results have shown that exposure to Mirazid treatment had a severe impact on egg production by TCBZ-resistant flukes, an effect that was mediated by disruption of the vitelline cells and of the mechanism co-ordinating egg formation in the ootype.

Gametogenesis and reproductive cycle of Melanorivulus aff. punctatus (Boulenger, 1895 (Cyprinodontiformes, Rivulidae in Chapada dos Guimarães, Mato Grosso, Brazil

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Monica Cassel

Full Text Available The comprehension of the reproductive cycle allows to understand which are the morphological changes that develop in the gonad during this interval. Thus, many studies have been undertaken in order to describe and classify the stages of gonadal development and reproductive status of Neotropical fishes. For this purpose, specimens of Melanorivulus aff. punctatus were collected in a permanent dam in Chapada dos Guimarães, Mato Grosso, Brazil. The gonads were prepared for analysis by light microscopy. The oogenesis and spermatogenesis have been described, characterizing the stages of gonadal development, together with assessments of the gonadosomatic ratio, germ cell count and verification of variation of mature oocytes in females. Throughout the year the male gonads presented themselves as capable of reproducing, characterized by the presence of undifferentiated and differentiated spermatogonia, spermatocytes organized into cysts, spermatids in cysts whose wall was thicker and the spermatozoa was free in the lumen and the duct. This can indicate a continuous reproductive cycle with split spermiation. The females had gonads in the development stage from May to September with undifferentiated and differentiated oogonias and early oocytes always facing the lumen, abundant pre-vitellogenic and vitellogenic oocytes and some atresias. In the phase capable of spawning, observed from October to March, the mature oocytes are abundant, there are many post-ovulatory complexes and some atresia in advanced stage. The regression, observed in some individuals from February to April, is characterized by ovaries with many atresias and post-ovulatory complexes. The same results were found in the quantitative assessments. Therefore, it may be characterized as discontinuous cycle with split spawning. Thus, the reproductive cycle of this species can be characterized as continuous for males and discontinuous for females, which have a most intense phase of reproduction

Conserved form and function of the germinal epithelium through 500 million years of vertebrate evolution.

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Grier, Harry J; Uribe, Mari Carmen; Lo Nostro, Fabiana L; Mims, Steven D; Parenti, Lynne R

2016-08-01

The germinal epithelium, i.e., the site of germ cell production in males and females, has maintained a constant form and function throughout 500 million years of vertebrate evolution. The distinguishing characteristic of germinal epithelia among all vertebrates, males, and females, is the presence of germ cells among somatic epithelial cells. The somatic epithelial cells, Sertoli cells in males or follicle (granulosa) cells in females, encompass and isolate germ cells. Morphology of all vertebrate germinal epithelia conforms to the standard definition of an epithelium: epithelial cells are interconnected, border a body surface or lumen, are avascular and are supported by a basement membrane. Variation in morphology of gonads, which develop from the germinal epithelium, is correlated with the evolution of reproductive modes. In hagfishes, lampreys, and elasmobranchs, the germinal epithelia of males produce spermatocysts. A major rearrangement of testis morphology diagnoses osteichthyans: the spermatocysts are arranged in tubules or lobules. In protogynous (female to male) sex reversal in teleost fishes, female germinal epithelial cells (prefollicle cells) and oogonia transform into the first male somatic cells (Sertoli cells) and spermatogonia in the developing testis lobules. This common origin of cell types from the germinal epithelium in fishes with protogynous sex reversal supports the homology of Sertoli cells and follicle cells. Spermatogenesis in amphibians develops within spermatocysts in testis lobules. In amniotes vertebrates, the testis is composed of seminiferous tubules wherein spermatogenesis occurs radially. Emerging research indicates that some mammals do not have lifetime determinate fecundity. The fact emerged that germinal epithelia occur in the gonads of all vertebrates examined herein of both sexes and has the same form and function across all vertebrate taxa. Continued study of the form and function of the germinal epithelium in vertebrates

Histological organization of the female queen Devario regina (Fowler, 1934 during its juvenile stage

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Piyakorn Boonyoung

2016-02-01

Full Text Available Limited research has been reported in the basic information about the structural organizations of fish organs in their juvenile state that could be used as histopathological biomarkers. Thus, the histological structures of important organs of the female fish Devario regina (Fowler, 1934 during its juvenile stage were exclusively examined using histological and histochemical approaches. Specimens were collected during the fishing season (July and October 2010 from the Tapee river, Thailand. Using histological analysis, the digestive system was distinctly composed of two parts; the digestive tract and accessory organs (liver and pancreas. Based on their histological structure, the epithelial organization of the oral cavity and pharynx was lined by stratified epithelium whereas the intestine was covered by a simple columnar epithelium and contained several goblet cells. The goblet cells were negatively stained with hematoxylin and eosin (H&E and Masson’s Trichrome (MT. In contrast, they were positively stained with Periodic Acid Schiff reaction (PAS and aniline blue (AB. The liver tissue in this fish was composed of polyhedral hepatocytes, with their sinusoids being distinctly located between the hepatocytes. The sinusoids were lined by a simple squamous epithelium. The pancreatic parenchyma mainly consisted of pyramidal cells that rested on a basal lamina in the acinar. Moreover, the pancreatic cells had a basophilic cytoplasm, a distinct basal nucleus and contained large eosinophilic zymogen granules. The excretory system especially referred to the kidney, and was composed of renal tubules and hematopoietic tissue. The female reproductive system was the ovary that was surrounded by a tunica albuginea. The ovary contained oocytes at differential stages of development including oogonia and the previtellogenic stage. Finally, the integument of this species consisted mainly of three layers of epidermis, dermis and hypodermis, respectively.

Analysis of the predetermining effect of a sex realizer by ovary transplantations in the monogenic flyChrysomya rufifacies.

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Ullerich, Fritz-Helmut

1980-02-01

In the heterozygousF'/f female-producing females of the strictly monogenic blowflyChrysomya rufifacies the gene product of the dominant or epistatic female sex realizerF' which causes sexpredetermination is thought to be synthesized either by cells of the germ line (oocytes, nurse cells or oogonia) or by somatic cells and then transferred into the oocytes. To determine the possible site of synthesis, reciprocal transplantations were made of prepupal ovaries between female-producing (thelygenic; t) and male-producing (arrhenogenic; a) females ofChrysomya rufifacies. In another series of experiments prepupal host females of the wild t-type and a-type were each provided with one additional ovary either from a0type (f/f) or a t-type (F'/f) prepupa (neither were distinguishable by their phenotypes). In all these experiments the donor females were marked by the recessive sex-linked mutation 'white' (w/w); white eyes, white Malpighian tubules). In a considerable number of cases the implanted ovaries were in contact with the host's own oviduct and grew normally, but the rate of hatched adults was somewhat reduced. Crosses between such host females andw/w males (f/f) produced female or male offspring with white eyes from the eggs of the implantedw/w ovary, as well as flies with wild-type eyes (+/w) which had developed in the host's own ovaries. In all cases so far examined, the genetically thelygenic (or arrhenogenic) host females with an additional ovary implanted from an arrhenogenic (thelygenic) donor, produced progeny of both sexes: sons (daughters) from the eggs of the donor's ovary and daugthers (sons) from the eggs of the host's own gonads.These results demonstrate that the ovaries of the t-females ofChrysomya rufifacies at least from the early prepupal stage, are autonomous for the product of theF' gene. Transplantations of the premordial germ cells (pole cells) are planned to find out whether the predeterminingF' gene product is synthesized before the prepupal

Gonad development during the early life of Octopus maya (Mollusca: Cephalopoda).

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Avila-Poveda, Omar Hernando; Colin-Flores, Rafael Francisco; Rosas, Carlos

2009-02-01

Gonad development during the early life of Octopus maya is described in terms of histological, morphometric, oocytes growth, and somatic-oocyte relationship data obtained from octopus cultured at the UMDI-UNAM, in Sisal, Yucatan, Mexico. This study is the first publication on gonad development during the early life of Octopus maya. A total of 83 O. maya specimens were used; their sizes ranged from 6.5 to 76 mm of total length (TL), 4 to 28 mm of dorsal mantle length (DML), 2.5 to 20 mm of ventral mantle length (VML), and 0.0180 to 7.2940 g of fixed body weight (fBW). Animals were weighed and measured only after preservation. A loss of 10% of living weight was estimated for juvenile octopuses after formalin preservation. The relation of length to weight (VML, DML, TL/fBW) pooled for both sexes had a strong positive correlation (r), as shown by a potential power function that was quite close to 1. Compound images were produced from numerous microscopic fields. The histological examination revealed that, 4 months after hatching, male octopus (24.5 mm DML and 7.2940 g fBW) were in gonad stages 2 (maturing) to 3 (mature), with spermatogonia and spermatocytes in the tubule wall and abundant spermatids and spermatozoa in the central lumen of the seminiferous tubules, suggesting the occurrence of different phases of gonad development at different maturity stages. In contrast, females (22.5 mm DML and 4.8210 g fBW) at the same time since hatching were immature (stage 1), with many oogonia, few oocytes, and germinal epithelium. This suggests that males reach maturity earlier than females, indicating a probable onset of maturity for males at around 4 months of culture or 8 g of wet body weight. Our results indicate the possibility that the size-at-weight can be recognized early with a degree of certainty that allows the sexes to be separated for culture purposes; but more detailed studies on reproduction in relation to endocrinology and nutrition are needed.

Immunoprotection of gonads and genital tracts in human embryos and fetuses: immunohistochemical study.

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Gurevich, A; Ben-Hur, H; Moldavsky, M; Szvalb, S; Berman, V; Zusman, I

2001-12-01

The immune protection of genital organs in embryogenesis has not been sufficiently studied. The purpose of this study was to investigate the development of the secretory immune system (SIS) in the gonads and genital tracts of human embryos and fetuses. Developing gonads at different stages and genital tracts from 18 embryos and 39 fetuses in the first to third trimester of gestation were analyzed for presence of different component of SIS: secretory component (SC), joining (J) chain. IgA, IgM, IgG, macrophages, and subsets of lymphocytes. The material was divided into two groups: cases not subjected to foreign antigenic effects (group I, n = 31) and those under antigenic attack (chorioamnionitis, group II, n = 26). In embryos and fetuses of group I, SC, J chain, and IgG were seen in the epithelium of mesonephric and paramesonephric ducts, proliferating coelomic epithelium, epithelium of the uterine tubes and uterus, epithelium of the vas deferens, epididymis, and rete testis. IgA and IgM appeared in 6-week-old embryos. J chain, IgA, IgM, and IgG, but not SC, were found in the primary oocytes and oogonia, spermatogonia. and interstitial cells. An abundance of macrophages was seen in 4-week-old embryos. T and B lymphocytes first appeared in 6-7-week-old embryos. In embryos and fetuses of group II, reactivity of immunoglobulins (Igs) decreased until they disappeared altogether. Components of SIS were seen in genital organs in 4-5-week-old embryos and were present during the whole intrauterine period. We suggest the presence of two forms of immune protection of fetal genital organs. One form contains SC, J chain, and Igs and is present in the genital tract epithelium. The second form contains only J chain and Igs and is present in germ cells of gonads. The loss of Igs in cases with chorioamnionitis reflects the functional participation of the SIS of genital organs in response to antigen attack.

Analysis of the behavior of mitochondria in the ovaries of the earthworm Dendrobaena veneta Rosa 1839.

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Justyna Faron

Full Text Available We examined six types of cells that form the ovary of the earthworm Dendrobena veneta ogonia, prooocytes, vitellogenic oocytes, trophocytes, fully grown postvitellogenic oocytes and somatic cells of the gonad. The quantitative stereological method revealed a much higher "volume density" of mitochondria in all of the types of germ-line cells except for the somatic cells. Fluorescent vital stain JC-1, however, showed a much higher oxidative activity of mitochondria in the somatic cells than in the germ-line cells. The distribution of active and inactive mitochondria within the studied cells was assessed using the computer program ImageJ. The analysis showed a higher luminosity of inactive mitochondria in all of the types of germ-line cells and a higher luminosity of active mitochondria in somatic cells. The OXPHOS activity was found in somatic cells mitochondria and in the peripheral mitochondria of the vitellogenic oocytes. The detection of reactive oxygen species (ROS revealed a differentiated distribution of ROS in the different cell types. The amount of ROS substances was lower in somatic cells than in younger germ-line cells. The ROS level was also low in the cytoplasm of fully grown postwitellogenic oocytes. The distribution of the MnSOD enzyme that protects mitochondria against destructive role of ROS substances was high in the oogonia and in prooocytes and it was very high in vitellogenic and postvitellogenic oocytes. However, a much lower level of this protective enzyme was observed in the trophocytes and the lowest level was found in the cytoplasm of somatic cells. The lower mitochondrial activity and higher level of MnSOD activity in germ-line cells when compared to somatic cells testifies to the necessity of the organisms to protect the mitochondria of oocytes against the destructive role of the ROS that are produced during oxidative phosphorylation. The protection of the mitochondria in oocytes is essential for the transfer of healthy

Phytophthora Root and Crown Rot on Apples in Bulgaria

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Mariana Nakova

2010-01-01

Full Text Available Phytophthora is a genus of Oomycota responsible for some of the most serious diseases with great economic impact (Judelson and Blanco, 2005. While 54 species were found in the 20th century (Erwin and Ribeiro, 1996 another 51-54 new species have been identified(Brasier, 2008 since the year 2000. They are spread worldwide and have broad range of host plants – fruit trees, citrus, forest and park species. Phytophthora can cause serious damages in orchards and nurseries of apples, cherries, etc. In Bulgaria they have been found first on young apples and cherries (1998-1999 in Plovdiv region (Nakova, 2003. Surveys have been done for discovering disease symptoms in Plovdiv and Kjustendil regions. Isolates have been obtained from infected plant material (roots and stem bases applying baiting bioassay (green apples, variety Granny Smith and/or PARP 10 selective media. Phytophthora strains were identified based on standard morphology methods – types of colonies on PDA, CMA, V 8, type and size of sporangia, oogonia and antheridia, andoospores. Cardial temperatures for their growth were tested on CMA and PDA.For molecular studies, DNA was extracted from mycelium using the DNA extraction kit.DNA was amplified using universal primers ITS 6 and ITS 4. Amplification products concentrations were estimated by comparison with the standard DNA. Sequencing was done at the Scottish Crop Research Institute (SCRI, Dundee, Scotland. Phytophthora root and crown rot symptoms first appear in early spring. Infected trees show bud break delay, have small chlorotic leaves, and branches die all of a sudden. Later symptoms are found in August-September. Leaves of the infected trees show reddish discoloration and drop down. Both symptoms are connected with lesions (wet, necrotic in appearance at stem bases of the trees.Disease spread was 2-3% in most gardens, only in an apple orchard in Bjaga (Plovdiv region it was up to 8-10%. Morphologically, the isolates acquired from

A new ELSA time series of tephra layers and paleobotanical evidence from laminated Eifel maar sediments covering the entire last 120,000 years

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Sirocko, Frank; Knapp, Hannes; Klee, Marlies; Rothacker, Leo; Kromer, Bernd

2014-05-01

The ELSA Project has drilled a total of 50 sediment cores (2000 m of laminated lake sediment) from Eifel maar lakes and dry maar structures during the last 15 years. These records have been dated using 7 different methods, including 370 14C dates. Ten records reveal the established palynological succession of trees during the Holocene down to the Laacher See Tephra, which is used for synchronization with seven more recently drilled laminated sediment cores, which all are 14C-dated too and analyzed for tephra, pollen and paleobotanical macroremains. The seven newly established records reveal a continuous MIS2 section with mosses, ostracods and characea oogonia. They show that the 28.000 - 40.000 BP has witnessed an open landscape dominated by grass, but with rhythmic spread of conifer trees following the Greenland interstadial/succession. Seeds of Ranunculae provide excellent material for 14C dating. Even deciduous trees are present in small amounts until 28.000 BP. The time from 48.000 to 40.000 BP is characterized by a pronounced transition from the open landscape to an early MIS3 spruce (Picea) dominated forest during Greenland Interstadial GI17-14. Modern man apparently arrived at the end of this principal vegetation change near 40,000 BP. Volcanic activity in the Eifel had a stable and pronounced recurrence from 55,000 - 30,000 BP every 4000 years, but commenced with the beginning of MIS2. This landscape evolution with a forested early MIS3 is quite different to peat and sediment records from Netherlands/ Northern Germany/Scandinavia/ Poland, but is similar to conditions in parts of Switzerland. We address the early MIS3 forest to the nearby continuously moist soils and warm conditions in the nearby Mosel valley, i.e. on those stands where wine is growing today, and which most likely had served as a local refugia even for deciduous trees during MIS4 and MIS3. The MIS5 sections of the presented ELSA records reach down at least to the beginning of MIS5d near 118

Effects of specific and prolonged expression of zebrafish growth factors, Fgf2 and Lif in primordial germ cells in vivo

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Wong, Ten-Tsao, E-mail: wong20@purdue.edu [Department of Animal Sciences, Purdue University, 901 W. State Street, West Lafayette, IN 47907 (United States); Collodi, Paul [Department of Animal Sciences, Purdue University, 901 W. State Street, West Lafayette, IN 47907 (United States)

2013-01-04

Highlights: Black-Right-Pointing-Pointer We discovered that nanos3 3 Prime UTR prolonged PGC-specific protein expression up to 26 days. Black-Right-Pointing-Pointer Expression of Fgf2 in PGCs significantly increased PGC number at later developmental stages. Black-Right-Pointing-Pointer Expression of Lif in PGCs resulted in a significant disruption of PGC migration. Black-Right-Pointing-Pointer Lif illicited its effect on PGC migration through Lif receptor a. Black-Right-Pointing-Pointer Our approach could be used to achieve prolonged PGC-specific expression of other proteins. -- Abstract: Primordial germ cells (PGCs), specified early in development, proliferate and migrate to the developing gonad before sexual differentiation occurs in the embryo and eventually give rise to spermatogonia or oogonia. In this study, we discovered that nanos3 3 Prime UTR, a common method used to label PGCs, not only directed PGC-specific expression of DsRed but also prolonged this expression up to 26 days post fertilization (dpf) when DsRed-nanos3 3 Prime UTR hybrid mRNAs were introduced into 1- to 2-cell-stage embryos. As such, we employed this knowledge to express zebrafish leukemia inhibitory factor (Lif), basic fibroblast growth factor (Fgf2) and bone morphogenetic protein 4 (Bmp4) in the PGCs and evaluate their effects on PGC development in vivo for over a period of 3 weeks. The results show that expression of Fgf2 significantly increased PGC number at 14- and 21-dpf while Bmp4 resulted in severe ventralization and death of the embryos by 3 days. Expression of Lif resulted in a significant disruption of PGC migration. Mopholino knockdown experiments indicated that Lif illicited its effect on PGC migration through Lif receptor a (Lifra) but not Lifrb. The general approach described in this study could be used to achieve prolonged PGC-specific expression of other proteins to investigate their roles in germ cell and gonad development. The results also indicate that zebrafish PGCs

Submerged terrestrial landscapes in the Baltic Sea: Evidence from multiproxy analyses of sediment cores from Fehmarnbelt

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Enters, Dirk; Wolters, Steffen; Blume, Katharina; Segschneider, Martin; Lücke, Andreas; Theuerkauf, Martin; Hübener, Thomas

2016-04-01

deposited during floods in old river channels of the hypothesized Dana River. Instead diatom assemblages indicate rather calm conditions. Between 9.850 and 8.900 cal. BP carbonate rich sediments were deposited under now shallow water conditions consisting of autochthonous carbonates, mollusk shells (especially Bithynia tentaculata) and oogonia of charophytes. The diatom record shows first indications of slightly brackish conditions starting ca. 10.300 cal. BP with the appearance of Mastogloia smithii which is about 2000 years older than the Littorina transgression dated in our record to around 8.300 cal. BP. This marine transgression finally inundated the inland lake and caused a rise of the water level of more than 20 m.

Estructura y la ultraestructura del ovario de Cichlasoma urophthalmus (Perciformes: Cichlidae

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Rubí Viedma

2011-06-01

windy, dry and rainy seasons. Female gonads were extracted and a portion was fixed in 4% formaldehyde for treatment for routine histology hematoxylin and eosin (HE and another part was processed for transmission electron microscopy (TEM. The gonads were fixed in 3% glutaraldehyde and 2% osmium tetroxide, followed by dehydrated in ethanol 50%, 70%, 80%, 95% and 100% for inclusion in Epon, thin sections were then prepared and were contrasted with lead citrate and uranyl acetate. The process of oocyte development can be divided into five distinct stages (formation of oocytes from oogonia, primary growth, lipid stage, vitellogenesis and maturation. In this work, we found that the primary growth stage is characterized by intense RNA synthesis and the differentiation of the vitelline envelope. Secondary growth starts with the accumulation of lipid droplets in the oocyte cytoplasm (lipid stage, which is then followed by massive uptake and processing of proteins into yolk platelets (vitellogenic stage. During the maturation stage, the lipid inclusions coalesce into a single oil droplet, and hydrolysis of the yolk platelets leads to the formation of a homogeneous mass of fluid yolk in mature eggs. In conclusion, further studies should elucidate structure and ultrastructural changes in the ovarian follicular components, in C. urophthalmus during different stages of oocyte growth. Rev. Biol. Trop. 59 (2: 743-750. Epub 2011 June 01.

Gonad development in females of fiddler crab Uca rapax (Crustacea, Brachyura, Ocypodidae using macro and microscopic techniques Desenvolvimento da gônada em fêmeas do caranguejo-violinista Uca rapax (Crustacea, Brachyura, Ocypodidae utilizando técnicas macro e microscópicas

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Daniela da Silva Castiglioni

2007-12-01

Full Text Available The morphology of the ovaries in Uca rapax (Smith, 1870 was described based on macroscopic and microscopic analysis. Females were collected in Itamambuca mangrove, Ubatuba, state of São Paulo, Brazil. In the laboratory, 18 females had their ovaries removed and prepared for histology. Each gonad developmental stage was previously determined based on external and macroscopic morphology and afterwards each stage was microscopically described. The ovaries of U. rapax showed a pronounced macroscopic differentiation in size and coloration with the maturation of the gonad, with six ovarian developmental stages: immature, rudimentary, developing, developed, advanced and spent. During the vitellogenesis, the amount of oocytes in secondary stage increases in the ovary, resulting in a change in coloration of the gonad. Oogonias, primary oocytes, secondary oocytes and follicular cells were histologically described and measured. In female’s ovaries of U. rapax the modifications observed in the oocytes during the process of gonad maturation are similar to descriptions of gonads of other females of brachyuran crustaceans. The similarities are specially found in the morphological changes in the reproductive cells, and also in the presence and arrange of follicle cells during the process of ovary maturation. When external morphological characteristics of the gonads were compared to histological descriptions, it was possible to observe modifications that characterize the process in different developmental stages throughout the ovarian cycle and, consequently, the macroscopic classification of gonad stages agree with the modifications of the reproductive cells.A morfologia dos ovários de Uca rapax foi descrita baseada nas análises macroscópica e microscópica. As fêmeas foram coletadas no manguezal de Itamambuca, Ubatuba, Estado de São Paulo, Brasil. No laboratório, os ovários de 18 fêmeas foram retirados e preparados para histologia. Os est

Reproductive Performance of Female Braconids Compared after (A) Brief and (B) Protracted Exposures to Ionizing Radiations

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Grosch, D. S. [Genetics Department, North Carolina State University, Raleigh, NC (United States)

1968-06-15

-rays and {sup 32}P {beta}-rays, has now been demonstrated for {gamma}-rays from the Raleigh {sup 60}CO Gammacell and the Woods Hole {sup 137}Cs source, although 1.4 times the X-ray dose is required to produce the same amount of damage. When the gamma exposure was spread over three days the valley did not appear until the eighth day. Females tested simultaneously and treated identically except that their X-ray exposure was brief provided the usual 7th-day low. Previously valley deferment was observed only when studying ingested radioisotopes where a necessary prestarvation obscured the significance. Another unpredicted response to the protracted gamma dose was a control level productivity of eggs derived from exposed oogonia. Recovery mechanisms were evidently able to keep pace with radiation damage. On the other hand, embryonic lethality was related to dose during all periods studied and dose rate was not important except for the most mature ooecytes. As scored by von Borstel categories, stage I deaths decreased and stage III types increased with age of the mothers until the latter predominated. This change is age-related and not dose-dependent. Biochemically, predominance of stage III death can be induced, even in eggs from young mothers, by feeding either RNA or protein inhibitors, but not by interfering with DNA synthesis. We postulate physiological involvement of nurse cells and fat body or their interrelations. Mean life span ranged from 19.52 {+-}1.34 days after 4320 R to 22.35 {+-}0.91 for controls. Biosatellite B, the second effort, was recovered successfully. After two days in orbit the reproductive performance of females differed strikingly from that repeated in ground controls. Most significant was egg deposit in a nearly contourless pattern reminiscent of a compensatory response to mitotic inhibition. (author)