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Results 201 - 250 of 2063
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Papagiannouli Fani - - 2009
Gonad development requires a coordinated soma-germline interaction that ensures renewal and differentiation of germline and somatic stem cells to ultimately produce mature gametes. The Drosophila tumour suppressor gene discs large (dlg) encodes a septate junction protein functioning during epithelial polarization, asymmetric neuroblast division, and formation of neuromuscular junctions. Here, we ...
Crockford Susan J - - 2009
In vertebrates, thyroid hormones (THs, thyroxine, and triiodothyronine) are critical cell signaling molecules. THs regulate and coordinate physiology within and between cells, tissues, and whole organisms, in addition to controlling embryonic growth and development, via dose-dependent regulatory effects on essential genes. While invertebrates and plants do not have thyroid glands, ...
Yamaguchi Sonoko - - 2009
Zinc (Zn) plays important roles in various biological activities but there is little available information regarding its functions in spermatogenesis. In our current study, we further examined the role of Zn during spermatogenesis in the Japanese eel (Anguilla japonica). Human CG (hCG) was injected into the animals to induce spermatogenesis, ...
Lau Nelson C NC Department of Molecular Biology, Massachusetts General Hospital, Boston, 02114, USA. - - 2009
Piwi proteins, a subclass of Argonaute-family proteins, carry approximately 24-30-nt Piwi-interacting RNAs (piRNAs) that mediate gonadal defense against transposable elements (TEs). We analyzed the Drosophila ovary somatic sheet (OSS) cell line and found that it expresses miRNAs, endogenous small interfering RNAs (endo-siRNAs), and piRNAs in abundance. In contrast to intact ...
Tasian Gregory E - - 2009
PURPOSE: We determined the relationship between clinical variables and testicular histopathological changes associated with decreased fertility potential in children with cryptorchidism. MATERIALS AND METHODS: Testis biopsies of 274 children who underwent orchiopexy and concurrent testicular biopsy between 1991 and 2001 were analyzed for germ and Leydig cell loss, and testicular ...
Godmann Maren M Institute of Anatomy, Developmental Biology, Hufelandstrasse 55, University of Duisburg-Essen Medical School, 45122 Essen, - - 2009
Krüppel-like factor 4 (Klf4, GKLF) was originally characterized as a zinc finger transcription factor essential for terminal differentiation and cell lineage allocation of several cell types in the mouse. Mice lacking Klf4 die postnatally within hours due to impaired skin barrier function and subsequent dehydration. Recently, KLF4 was also used ...
Lie Pearl P Y PP Center for Biomedical Research, New York, NY 10065, - - 2009
Throughout spermatogenesis, a select pool of germ cells, the leptotene spermatocytes, must traverse the blood-testis barrier (BTB) to enter the adluminal compartment of the seminiferous epithelium. This event requires extensive restructuring of cell junctions, and it must also coincide with germ cell cycle progression in preparation for primary spermatocyte meiosis. ...
Kim Jiyoung J Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, - - 2009
By screening C. elegans mutants for severe defects in germline proliferation, we isolated a new loss-of-function allele of cdc-25.1, bn115. bn115 and another previously identified loss-of-function allele nr2036 do not exhibit noticeable cell division defects in the somatic tissues but have reduced numbers of germ cells and are sterile, indicating ...
Kang S J - - 2009
This study was conducted to evaluate whether the sex of donor primordial germ cells (PGCs) influences production of chimeric semen from recipient hatchlings produced by interspecies transfer between pheasant (Phasianus colchicus) and chicken (Gallus gallus). Pheasant PGCs were retrieved from 7-d-old embryos and subsequently transferred into circulatory blood of 2.5-d-old ...
Gribbins K M - - 2009
Testicular tissues from Anolis lineatopus were examined histologically to determine testicular structure, germ cell morphologies, and the germ cell development strategy employed during spermatogenesis. Anoles (N=36) were collected from southern Jamaica from October 2004 to September 2005. Testes were extracted and fixed in Trump's fixative, dehydrated, embedded in Spurr's plastic, ...
Butler Lucy C LC Department of Physiology, Development and Neuroscience, University of Cambridge, - - 2009
Drosophila germ-band extension (GBE) is an example of the convergence and extension movements that elongate and narrow embryonic tissues. To understand the collective cell behaviours underlying tissue morphogenesis, we have continuously quantified cell intercalation and cell shape change during GBE. We show that the fast, early phase of GBE depends ...
McKinnell Chris C MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK. - - 2009
Fetal exposure of male rats to some phthalates induces reproductive abnormalities, raising concerns for similar effects in humans. In order to address this in a more appropriate animal model, the aim of the present studies was to investigate the effect of fetal/neonatal exposure to monobutyl phthalate (MBP) in a non-human ...
Sonne Si Brask SB Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark. - - 2009
Testicular germ cell cancers in young adult men derive from a precursor lesion called carcinoma in situ (CIS) of the testis. CIS cells were suggested to arise from primordial germ cells or gonocytes. However, direct studies on purified samples of CIS cells are lacking. To overcome this problem, we performed ...
Wojtasz Lukasz - - 2009
Analysis of female mammalian germ cells has been hindered by difficulties in isolating high purity germ cell populations from embryonic and fetal gonads. Meiotic prophase stage oocytes are particularly difficult to isolate due to the lack of suitable surface markers. Oct4 promoter driven GFP expression has been used to distinguish ...
Looijenga Leendert H J - - 2009
Human germ cell tumours (GCTs) comprise several types of neoplasias with different pathogeneses and clinical behaviours. A classification into five subtypes has been proposed. Here, the so-called type II testicular GCTs (TGCTs), ie the seminomas and non-seminomas, will be reviewed with emphasis on pathogenesis and clinical implications. Various risk factors ...
Chung Sanny S W - - 2009
Signaling through vitamin A metabolites is indispensable for spermatogenesis, and disruption of retinoic acid receptor alpha (RARalpha) function resulted in male sterility and aberrant spermatogenesis, which resembled vitamin A deficiency. Here we investigated the lineage- and cell-specific role of RARalpha-mediated signaling during spermatogenesis using germ-cell transplantation and genetically manipulated mouse ...
Childs Andrew J - - 2009
Germ cell-expressed activin A promotes germ cell survival and proliferation indirectly, possibly by maintaining ovarian pregranulosa cells in an undifferentiated state and preventing primordial follicle formation until oocytes have matured sufficiently. We have previously demonstrated that recombinant activin A can repress the expression of Kit ligand (KITLG) in cultures of ...
Garverick H A - - 2010
Estradiol-17beta is the predominant steroid produced during early stages of ovarian development in ruminants and steroid hormones have been hypothesized to regulate ovigerous cord formation, germ cell meiosis and ovarian vascular development. Therefore, the objective was to determine the presence and localization of mRNA and protein encoding cytochrome P450 aromatase ...
Carella Francesca - - 2009
Germinoma is a gonadal neoplasm originating from progenitor cells in germinal epithelium. Frequently described in some populations of bivalve molluscs, to our knowledge, germinoma has never been reported in gastropods so far. In this paper we describe the histopathological findings of some atypical cellular masses, originating in the undifferentiated germ ...
Rosner Amalia - - 2009
Germ cell sequestering in Animalia is enlightened by either, launching true germ line along epigenetic or preformistic modes of development, or by somatic embryogenesis, where no true germ line is set aside. The research on germ line-somatic tissue segregation is of special relevancy to colonial organisms like botryllid ascidians that ...
Huser Thomas - - 2009
Healthy human males produce sperm cells of which about 25-40% have abnormal head shapes. Increases in the percentage of sperm exhibiting aberrant sperm head morphologies have been correlated with male infertility, and biochemical studies of pooled sperm have suggested that sperm with abnormal shape may contain DNA that has not ...
De Felici Massimo - - 2009
Embryonic stem (ES) cells do not exist in nature but, usually produced from the inner cell mass (ICM) of the blastocyst, are considered equivalent to ICM cells captured during a short period of transient self-renewal and pluripotency capability. Although, artificial, ES cells represent a formidable model to investigate fundamental aspects ...
Tam Patrick P L - - 2009
Male germ cells are induced to form from the epiblast of the mouse embryo by a combination of WNT and bone morphogenetic protein signals. Ohinata et al. (2009) now clarify the steps of mouse germ cell formation and use this genetic insight to direct the specification and differentiation of germline ...
Ohinata Yasuhide - - 2009
Specification of the germ cell lineage is vital to development and heredity. In mice, the germ cell fate is induced in pluripotent epiblast cells by signaling molecules, yet the underlying mechanism remains unknown. Here we demonstrate that germ cell fate in the epiblast is a direct consequence of Bmp4 signaling ...
Tyagi Gaurav G Department of Veterinary Biosciences and Pathobiology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, - - 2009
Mice that are ets variant gene 5 (ETV5) null (Etv5(-/-)) undergo the first wave of spermatogenesis but lose all spermatogonial stem cells (SSCs) during this time. The SSC loss in Etv5(-/-) mice begins during the neonatal period, suggesting a role for ETV5 in SSC self-renewal during this period. Herein, we ...
Hara Kenshiro - - 2009
During mouse gastrulation, primordial germ cells (PGCs) become clustered at the base of the allantois and move caudally into the hindgut endoderm before entering the genital ridges. The precise roles of endoderm tissues in PGC migration, however, remain unclear. By using Sox17 mutants with a specific endoderm deficiency, we provide ...
Rey Florencia - - 2009
The increased use of agrochemical pesticides, such as atrazine (ATZ) and endosulfan (END), may have a significant impact on ecosystem health and biodiversity. The aim of this study was to investigate the consequences of in ovum exposure to ATZ and END on Caiman latirostris gonadal histo-functional features. Caiman eggs were ...
Chen Zhong - - 2009
The Retinoblastoma (Rb) protein is a conserved repressor of cell proliferation. In animals and plants, deregulation of Rb protein causes hyperproliferation and perturbs cell differentiation to various degrees. However, the primary developmental impact of the loss of Rb protein has remained unclear. In this study we investigated the direct consequences ...
Schulz R?diger W - - 2010
Spermatogenesis is a developmental process during which a small number of diploid spermatogonial stem cells produce a large number of highly differentiated spermatozoa carrying a haploid, recombined genome. We characterise morphologically the different germ cell stages with particular attention for the spermatogonial generations, including the stem cells and their specific ...
Rheubert J L - - 2009
Ground Skink (Scincella lateralis) testes were examined histologically to determine the testicular organization and germ cell development strategy employed during spermatogenesis. Testicular tissues were collected from 19 ground skinks from Aiken County, South Carolina during the months of March-June, August, and October. The testes consisted of seminiferous tubules lined with ...
Salonen Jonna - - 2009
The peak incidence of malignant ovarian germ cell tumours occurs soon after puberty. Thus, gonadal steroids may play a role in their development. Oestrogen receptors (ERalpha and ERbeta) and their co-regulators, including small nuclear ring finger protein 4 (SNURF/RNF4) mediate oestrogen actions. While ERbeta and SNURF are down-regulated in testicular ...
Park Tae Sub - - 2009
The derivation of germ cells from human embryonic stem cells (hESCs) or human induced pluripotent stem (hIPS) cells represents a desirable experimental model and potential strategy for treating infertility. In the current study, we developed a triple biomarker assay for identifying and isolating human primordial germ cells (PGCs) by first ...
Navarro Pablo - - 2009
The integration of X-inactivation with development is a crucial aspect of this classical paradigm of epigenetic regulation. During early female mouse development, X-inactivation reprogramming occurs in pluripotent cells of the inner cell mass of the blastocyst and in pluripotent primordial germ cells. Here we discuss the developmental strategies which ensure ...
Lavial Fabrice - - 2009
When they are derived from blastodermal cells of the pre-primitive streak in vitro, the pluripotency of Chicken Embryonic Stem Cells (cESC) can be controlled by the cPouV and Nanog genes. These cESC can differentiate into derivatives of the three germ layers both in vitro and in vivo, but they only ...
Antonangeli Fabrizio - - 2010
OBJECTIVE: To study the effect of c-FLIP overexpression in testicular germ cells. DESIGN: A novel transgenic mouse model overexpressing the apoptotic modulator c-FLIP in the testis was generated. SETTING: Animal facility and university research laboratory. ANIMAL(S): Transgenic mice overexpressing the long isoform of c-FLIP (c-FLIP(L)) under the transcriptional control of ...
Gu Ying Y Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, - - 2009
Steel factor is an essential survival and proliferation factor for primordial germ cells (PGCs) during their migration in the early mouse embryo. PGCs arise during gastrulation, and migrate into the posterior endoderm that becomes the hindgut. Previous reports have suggested that PGCs become dependent on Steel factor when they colonize ...
Kipfer S - - 2009
A high prevalence of gonad morphological variations has been observed in whitefish Coregonus lavaretus from Lake Thun (Switzerland). To clarify the role of endocrine disruption as a possible cause of the gonad alterations, whitefish were reared in a long-term laboratory experiment under exposure to 17 beta-estradiol (E2). Fish were fed ...
Lau Yun-Fai Chris - - 2009
The gonadoblastoma (GBY) locus is the only oncogenic locus on the human Y chromosome. It is postulated to serve a normal function in the testis, but could exert oncogenic effects in dysgenetic gonads of individuals with intersex and/or dysfunctional testicular phenotypes. Recent studies establish the testis-specific protein Y-encoded (TSPY) gene ...
Oktem Ozgur - - 2009
It is a central dogma in reproductive biology that oogenesis is completed before or just after birth and that the postnatal ovary is endowed by a fixed and non-renewing number of oocytes in mammals. However, this widely accepted doctrine was recently challenged by studies showing regeneration of oocytes from putative ...
Brownfield Lynette - - 2009
The unique double fertilisation mechanism in flowering plants depends upon a pair of functional sperm cells. During male gametogenesis, each haploid microspore undergoes an asymmetric division to produce a large, non-germline vegetative cell and a single germ cell that divides once to produce the sperm cell pair. Despite the importance ...
Freiman Richard N RN Department of Molecular and Cell Biology, Brown University, 70 Ship St., Box G-E4, Providence, RI 02903, USA. - - 2009
Through the reductive divisions of meiosis, sexually reproducing organisms have gained the ability to produce specialized haploid cells called germ cells that fuse to establish the diploid genome of the resulting progeny. The totipotent nature of these germ cells is highlighted by their ability to provide a single fertilized egg ...
Müller Thomas - - 2009
BACKGROUND: Embryonic stem cells (ESC) hold great promise for the treatment of degenerative diseases. However, before clinical application of ESC in cell replacement therapy can be achieved, the safety and feasibility must be extensively tested in animal models. The common marmoset monkey (Callithrix jacchus) is a useful preclinical non-human primate ...
Chau Johnnie J Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4955, - - 2009
In Drosophila, the female-specific SEX-LETHAL (SXL) protein is required for oogenesis, but how Sxl interfaces with the genetic circuitry controlling oogenesis remains unknown. Here we use an allele of sans fille (snf) that specifically eliminates SXL protein in germ cells to carry out a detailed genetic and cell biological analysis ...
Liu Xiaochun - - 2009
To study the rapid action of estrogen on the male reproductive system in teleost, a full-length cDNA homologous to the seven-transmembrane receptor GPER of humans and rodents was cloned from the testis of zebrafish. Biological characterization of this cloned zebrafish gper was performed based on its functional expression in cultured ...
La Sala Gina - - 2009
Lindane (gamma-HCH) was examined for its effect on primordial germ cell (PGC) development in the mouse embryo. We found that exposure by gavage of pregnant mice to 15 or 30 mg/kg/bw lindane during the period of PGC migration and gonad colonization (from 8.5 to 11.5 days post coitum, dpc) resulted ...
Arany Szilvia - - 2009
Here, we report on the first attempt to bioengineer tooth using a spontaneously immortalized mesenchymal cell line. To assess the odontogenic potential of this cell line, odontoblast-lineage cells (OLC) were re-associated with competent dental epithelium isolated from E14.5 mice. A novel three-dimensional organ germ culture method was applied to nurture ...
Ricardo Sara - - 2009
Directed cell migration, which is critical for embryonic development, leukocyte trafficking, and cell metastasis, depends on chemoattraction. 3-hydroxy-3-methylglutaryl coenzyme A reductase regulates the production of an attractant for Drosophila germ cells that may itself be geranylated. Chemoattractants are commonly secreted through a classical, signal peptide-dependent pathway, but a geranyl-modified attractant ...
Kocer Ayhan A MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, - - 2009
One of the major decisions that germ cells make during their development is whether to differentiate into oocytes or sperm. In mice, the germ cells' decision to develop as male or female depends on sex-determining signalling molecules in the embryonic gonadal environment rather than the sex chromosome constitution of the ...
Bouskine Adil - - 2010
Testicular germ cell tumours (TGCTs), the most frequent solid tumour of the young men, originate from the primitive germ cells. They share some pluripotency stem-cell markers which may help to distinguish between seminoma, the most frequent TGCTs and non-seminoma tumours, such as embryonal carcinoma, teratocarcinoma or choriocarcinoma. Due probably to ...
Renault Andrew D AD HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, - - 2009
In many species, the germ cells, precursors of sperm and egg, migrate during embryogenesis. The signals that regulate this migration are thus essential for fertility. In flies, lipid signals have been shown to affect germ cell guidance. In particular, the synthesis of geranylgeranyl pyrophosphate through the 3-hydroxy-3-methyl-glutaryl coenzyme A reductase ...
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