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Results 551 - 600 of 2063
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Tadokoro Ryosuke - - 2006
Although regeneration studies are useful for understanding how organs renew, little information is available about regeneration of reproductive organs and germ cells. We here describe the behavior of germ-cell precursors during regeneration of the oligochaete annelid worm Enchytraeus japonensis, which has the remarkable feature of undergoing asexual (by fission) and ...
Kim Heebal - - 2006
We established a database to study germ cells during the early developmental stage in the chicken. The ChickGCE database provides integrated expressed sequence tag (EST) data from chicken testis, ovary, embryonic gonads, and primordial germ cells. We gathered data on 10,294 ESTs from approximately 1000 embryonic gonads, and we experimentally ...
Sugiyama Ryuji - - 2006
Silene latifolia is a dioecious plant in which sex is determined by heteromorphic sex chromosomes. In female plants, stamen development is arrested before microspore mother cells are formed. In this study, we isolated four cDNAs (SlSKP1-1 to 4) encoding ASK1-like protein as expression markers to reveal when expression levels are ...
Ancelin Katia - - 2006
Blimp1, a transcriptional repressor, has a crucial role in the specification of primordial germ cells (PGCs) in mice at embryonic day 7.5 (E7.5). This SET-PR domain protein can form complexes with various chromatin modifiers in a context-dependent manner. Here, we show that Blimp1 has a novel interaction with Prmt5, an ...
Kubo Shuji - - 2006
Whether long interspersed element-1 (L1 or LINE-1) retrotransposition can occur in quiescent, nondividing, and/or terminally differentiated somatic cells has remained an unanswered fundamental question in human genetics. Here, we used a ubiquitously active phosphoglycerate kinase-1 promoter to drive the expression of a highly active human L1 element from an adenovirus-L1 ...
Rieux-Laucat Frédéric - - 2006
A four-month-old boy with primary immunodeficiency was found to have a homozygous germ-line mutation of the gene encoding the CD3zeta subunit of the T-cell receptor-CD3 complex. CD3zeta is necessary for the development and function of T cells. Some of the patient's T cells had low levels of the T-cell receptor-CD3 ...
Yamaguchi Yasuka L - - 2006
Importin-mediated transport of cargoes is known to be a key mechanism for nucleo-cytoplasmic trafficking of molecules. Ipo13, which is a member of Importin-beta gene family, encodes two transcripts by utilizing different transcription start sites. In the mouse, the full-length transcript (L-Ipo13) is expressed in the primordial germ cells in the ...
Crittenden Sarah L SL Howard Hughes Medical Institute, Department of Biochemistry, Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA. - - 2006
The Caenorhabditis elegans germ line provides a model for understanding how signaling from a stem cell niche promotes continued mitotic divisions at the expense of differentiation. Here we report cellular analyses designed to identify germline stem cells within the germline mitotic region of adult hermaphrodites. Our results support several conclusions. ...
Wu Jianhong J Biochemistry Department, PO Box 3711, Duke University Medical Center, Research Drive, Durham, NC 27710, - - 2006
Through mutagenesis by P-element transposition, we identified a series of mutants with deletions in topoisomerase 3beta gene (top3beta) and an adjacent, previously uncharacterized gene CG15897, here named wuho (wh). Whereas top3beta truncation does not affect viability or fertility, wh null mutants display male sterile and female semi-sterile phenotypes. Furthermore, wh ...
Voorhees Jessica C - - 2006
This report describes development of a method for enhanced cell elution from cotton swabs. The method exploits an enzyme mixture for digestion of the cotton to remove intact cells, and can be utilized in conjunction with or to circumvent conventional differential extraction (DE). Samples digested with Aspergillus niger cellulase yielded ...
Yoshimura Yasunori - - 2006
The birth announced in 1997 of Dolly, the lamb cloned from the somatic mammary cells of an adult ewe, and the discovery of human embryonic stem cells in 1998 have been the most exciting developments in the biological sciences in the past decade. Reproductive somatic cell nuclear transfer (SCNT) in ...
Novak Ivana - - 2006
Several recent studies have suggested that mouse embryonic stem cells (ESCs) can differentiate into female and male germ cells in vitro. The meiotic process in germ cell-like cells derived from ESCs has not been studied in detail, but it has been reported that synaptonemal complex protein-3 (SYCP3) is expressed in ...
Cools Martine - - 2006
PURPOSE: The purpose of the study was to define the histological origin of gonadoblastomas, allowing the identification of high-risk patients. EXPERIMENTAL DESIGN: Sixty paraffin-embedded gonadectomy or gonadal biopsy samples of 43 patients with gonadal dysgenesis were selected from our archives. We studied the morphology and immunohistochemical properties of the germ ...
Andrews, Ch. A.
The agglutination responses of three Drosophila cell lines to concanavalin A and wheat germ agglutinin have been examined. Although the cell lines were originally derived from late embryonic stages of the Ore-R strain of Drosophila melanogaster, they show quantitative differences in lectin-induced agglutination. Line 1 cells were least agglutinable with ...
Nakamura Shuhei - - 2006
The gonad contains two major cell lineages, germline and somatic cells. Little is known, however, about the somatic gonadal cell lineage in vertebrates. Using fate mapping studies and ablation experiments in medaka fish (Oryzias latipes), we determined that somatic gonadal precursors arise from the most posterior part of the sdf-1a ...
Zeng Wenxian - - 2006
Xenografting of immature mammalian testis tissue into mice can accelerate sperm production. To determine whether this shortened time to sperm production is because of reduced length of the spermatogenic cycle, we applied bromodeoxyuridine (BrdU) incorporation to analyze the spermatogenic cycle in porcine and ovine testis xenografts. Small testis fragments from ...
McClusky Leon M - - 2006
Naturally occurring heavy metals and synthetic compounds are potentially harmful for testicular function but evidence linking heavy metal exposure to reduced semen parameters is inconclusive. Elucidation of the exact stage at which the toxicant interferes with spermatogenesis is difficult because the various germ cell stages may have different sensitivities to ...
Catizone A - - 2006
The hepatocyte growth factor (HGF) is a pleiotropic cytokine that influences mitogenesis, motility and differentiation of many different cell types by its tyrosine kinase receptor c-Met. We previously demonstrated that the c-Met/HGF system is present and functionally active during postnatal testis development. We found also that spermatozoa express c-Met and ...
Brown Stephen S Faculty of Life Sciences, University of Manchester, C.1247 Michael Smith Building, Oxford Road, Manchester M13 9PT, U.K. - - 2006
The gonad is formed from two populations of cells originating at different locations: the primordial germ cells (PGCs), giving rise to either sperm or oocytes, and the somatic gonadal mesoderm precursors (SGPs), which support development of the gametes. Following the PGCs' migration during gastrulation, these two populations meet, forming the ...
Bowles Josephine - - 2006
Germ cells in the mouse embryo can develop as oocytes or spermatogonia, depending on molecular cues that have not been identified. We found that retinoic acid, produced by mesonephroi of both sexes, causes germ cells in the ovary to enter meiosis and initiate oogenesis. Meiosis is retarded in the fetal ...
Dyce Paul W - - 2006
Two of the unanswered questions in mammalian developmental biology are when and where the fate of the germ cell is specified. Here, we report that stem cells isolated from the skin of porcine fetuses have the intrinsic ability to differentiate into oocyte-like cells. When differentiation was induced, a subpopulation of ...
Rajpert-De Meyts Ewa - - 2006
Carcinoma in situ testis (CIS), also known as intratubular germ cell neoplasia (ITGCN), is a pre-invasive precursor of testicular germ cell tumours, the commonest cancer type of male adolescents and young adults. In this review, evidence supporting the hypothesis of developmental origin of testicular germ cell cancer is summarized, and ...
Michal Michal - - 2006
We present the morphological, immunohistochemical, and molecular genetic features of three cases of testicular and four cases of ovarian mixed germ cell sex cord-stromal tumors (MGSCT). The germ cells in the testicular MGSCTs morphologically differed from those in classical seminomas by lacking the typical "square off" quality of the nuclei. ...
DiNapoli Leo - - 2006
In addition to its role in somatic cell development in the testis, our data have revealed a role for Fgf9 in XY germ cell survival. In Fgf9-null mice, germ cells in the XY gonad decline in numbers after 11.5 days post coitum (dpc), while germ cell numbers in XX gonads ...
Méndez Carmen - - 2006
The gonadal development of chicken embryo is regulated by hormones and growth factors. Transforming growth factor beta (TGF-beta) isoforms may play a critical role in the regulation of growth in chicken gonads. We have investigated the effect of the TGF-beta isoforms on the number of germ and somatic cells in ...
Parker Heidi G - - 2006
In August 2005, Lee et al. reported the first cloning of a domestic dog from adult somatic cells. This putative dog clone was the result of somatic-cell nuclear transfer from a fibroblast cell of a three-year-old male Afghan hound into a donor oocyte provided by a dog of mixed breed. ...
Berney Daniel M - - 2006
Intratubular seminoma (ITS) has been defined as the complete filling of the seminiferous tubules with seminoma cells with no Sertoli cells present. This contrasts with intratubular germ cell neoplasia, unclassified (IGCNU), where the malignant germ cells are interspersed by Sertoli cells. We aimed to determine the relationship between these 2 ...
Ramasamy Srinivas - - 2006
In sexually reproducing organisms, primordial germ cells (PGCs) give rise to the cells of the germ line, the gametes. In many animals, PGCs are set apart from somatic cells early during embryogenesis. Work in Drosophila, C. elegans, Xenopus, and zebrafish has shown that maternally provided localized cytoplasmic determinants specify the ...
Celine J. Guigon
In mammals, the role played by germ cells in ovarian differentiation and folliculogenesis has been the focus of an increasing number of studies over the last decades. From these studies, it has emerged that bidirectional communication between germ cells and surrounding companion cells is required as soon as the initial ...
Hayashi Katsuhiko - - 2006
Meiosis is a specialized cell division that is essential to reduce the ploidy of the genome and to generate genomic diversity in all sexually reproducing organisms. Our recent investigation revealed that the meiosis-specific histone methyltransferase Meisetz (Meiosis-induced factor containing PR/SET domain and zinc-finger motif) played an essential role on proper ...
Law H - - 2006
The risk of subsequent development of testicular germ cell neoplasia is related to presence of underlying developmental defects such as cryptorchidism, in which the risk is around 0.5%, and XY intersex with abdominal testes, in which the risk may be as high as 20-25%. We examined the hypothesis that the ...
Yu Bing-Zhi - - 2006
In order to determine the function and possible relationship between Cdc2 and P(70)S6K, Western blot analysis and immunohistochemistry analysis were used to study the expression and kinase activity of Cdc2 and P(70)S6K in male mouse germ cells. With the maturation of germ cells in the testis, the expression of Cdc2 ...
Narbonne-Reveau Karine - - 2006
The fused gene encodes a serine-threonine kinase that functions as a positive regulator of Hedgehog signal transduction in Drosophila embryogenesis, wing morphogenesis, and somatic cell development during oogenesis. Here, we have characterized the germline ovarian tumors present in adult ovaries of fused mutant females, a phenotype not observed upon deregulation ...
Kumamoto Hiroyuki - - 2006
BACKGROUND: To clarify the roles of cell cycle regulation in oncogenesis and cytodifferentiation of odontogenic tumors, expression of retinoblastoma protein (RB) and E2 promoter-binding factor-1 (E2F-1) was analyzed in ameloblastomas as well as in tooth germs. METHODS: Tissue specimens of 10 tooth germs, 40 benign ameloblastomas, and five malignant ameloblastomas ...
Comitato Raffaella - - 2006
In mammals, retinoic acid is involved in the regulation of testicular function by interaction with two families of nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR). Among RAR isoforms, the testicular cells of the lizard were found to express only RARalpha (3.7 kb) and RARbeta (3.4 kb) ...
Schröder Reinhard - - 2006
The correct specification of germ cells during embryogenesis is a fundamental step in life that ensures the existence of the next generation. Although different species display various cellular modes of generating germ cells, the product of the vasa gene proves to be a reliable marker of primordial germ cells in ...
Solari Cristian A - - 2006
During the unicellular-multicellular transition, there are opportunities and costs associated with larger size. We argue that germ-soma separation evolved to counteract the increasing costs and requirements of larger multicellular colonies. Volvocalean green algae are uniquely suited for studying this transition because they range from unicells to multicellular individuals with germ-soma ...
Kotaja Noora - - 2006
The chromatoid body is a perinuclear, cytoplasmic cloud-like structure in male germ cells whose function has remained elusive. Here we show that the chromatoid body is related to the RNA-processing body of somatic cells. Dicer and components of microRNP complexes (including Ago proteins and microRNAs) are highly concentrated in chromatoid ...
Rival Claudia - - 2006
Experimental autoimmune orchitis (EAO) is an organ-specific model of autoimmunity characterized by an interstitial lymphomononuclear cell infiltrate as well as sloughing and apoptosis of germ cells. EAO was induced in adult male Sprague-Dawley rats by active immunization with testicular homogenate and adjuvants. Rats injected with saline solution and adjuvants were ...
Veeramachaneni D N Rao - - 2006
Testicular carcinoma in situ (CIS), which precedes germ cell tumours, has been associated with coexistence or a history of testicular maldescent in 20-30% of human cases. The objective of this study was to determine if the abdominal location of the testis by itself affects differentiation of germ cells and why ...
Petitte J N - - 2006
Presently, avian genetic resources are best maintained as living collections of birds. Unfortunately, these stocks have been under constant pressure to be destroyed because of the decline in the number of Poultry Science Departments and pressures to cut costs at land grant institutions. Cryopreservation of semen is often suggested as ...
Sunanaga Takeshi - - 2006
We investigated whether Vasa was a germline-specific marker in the colonial ascidian Botryllus primigenus, and whether it was inducible epigenetically in the adult life span. We cloned a Botryllus Vasa homologue (BpVas). The deduced open reading frame encoded 687 amino acid residues. It was expressed specifically by germline cells such ...
Adamah D J B - - 2006
Germ cell tumours (GCT) are thought to arise as the result of a defect in early development, probably shortly after arrival of the migrating primordial germ cells (PGC) in the genital ridge when, if in a male genital ridge, the germ cells arrest in mitosis, but in a female genital ...
Horvay Katja - - 2006
Germ plasm formation is considered to define the first step in germ cell development. Xenopus Dead end represents a germ plasm specific transcript that is homologous to the previously characterized zebrafish dead end, which is required for germ cell migration and survival. XDead end mRNA localizes to the vegetal pole ...
Yamaguchi Yasuka L - - 2006
The low density lipoprotein receptor-related protein 4 gene (Lrp4) was identified by subtractive screening of cDNAs of the migratory primordial germ cells (PGCs) of E8.5-9.5 embryo and E3.5 blastocysts. Lrp4 is expressed in PGCs in the hindgut and the dorsal mesentery of E9.5 embryos, and in germ cells in the ...
Kawakami T - - 2006
Genome-wide epigenetic modification plays a crucial role in regulating genome functions at critical stages of development. In particular, DNA methylation is known to be reprogrammed on a genome-wide level in germ cells and in preimplantation embryos, although it is relatively stable in somatic cells. In this reprogramming process, the genome ...
Mattiske Deidre - - 2006
Foxc1 encodes a forkhead/winged helix transcription factor expressed in many embryonic tissues. Previous studies have investigated defects in the urogenital system of Foxc1 null mutants, but the mechanisms underlying the abnormal development of the gonad have not been explored. From earliest stages, the mutant ovaries are smaller than normal, with ...
Rao Manjeet K - - 2006
Using a novel tissue-specific RNA interference (RNAi) approach that mimics the principle by which naturally occurring microRNAs (miRNA) are made, we demonstrate that the Wilms' tumor 1 (WT1) transcription factor has an essential role in spermatogenesis. Mice depleted of WT1 in Sertoli nurse cells suffered from increased germ cell apoptosis, ...
Familari Mary - - 2006
An analysis of embryonic stem cell (ESC) derivation in vertebrates has revealed that the potential to form ESC is dependent on the setting aside of a pluripotent lineage from extraembryonic lineages early in development. Derivation of ESCs from all amniotes and also many lower vertebrates with that pattern of lineage ...
Clark Amander T - - 2006
There has previously been no robust cell-based model for examining the genetic and epigenetic mechanisms of human germ cell formation. Human embryonic stem cells (hESCs) could potentially fill this need, as all cell types analyzed to date (including mature germ cells) can be identified by marker analysis during hESC differentiation. ...
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