Search Results
Results 251 - 300 of 2063
< 1 2 3 4 5 6 7 8 9 10 11 >
Cook Matthew S MS Department of Cell Biology, Duke University, Durham, NC, USA. - - 2009
A homozygous nonsense mutation (Ter) in murine Dnd1 (Dnd1(Ter/Ter)) results in a significant early loss of primordial germ cells (PGCs) prior to colonization of the gonad in both sexes and all genetic backgrounds tested. The same mutation also leads to testicular teratomas only on the 129Sv/J background. Male mutants on ...
Aramaki Shinya - - 2009
The dead end gene, coding an RNA binding protein, is predominantly expressed in the germ cells of vertebrates. Recently, we cloned chicken dead end homologue (CDH) and showed that expression of CDH mRNA is highly specific to primordial germ cells (PGCs) at early embryonic stages. To date, the subcelluler localization ...
Mich John K JK Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, - - 2009
Primordial germ cells (PGCs) are the progenitors of reproductive cells in metazoans and are an important model for the study of cell migration in vivo. Previous reports have suggested that Hedgehog (Hh) protein acts as a chemoattractant for PGC migration in the Drosophila embryo and that downstream signaling proteins such ...
Barbagallo Federica - - 2009
Protein kinases that regulate the centrosome cycle are often aberrantly controlled in neoplastic cells. Changes in their expression or activity can lead to perturbations in centrosome duplication, potentially leading to chromosome segregation errors and aneuploidy. Testicular germ cell tumours (TGCTs) are characterized by amplification of centrosomes through unknown mechanisms. Herein, ...
Marques-Mari A I - - 2009
BACKGROUND: Advances in stem cell research have opened new perspectives for regenerative and reproductive medicine. Stem cells (SC) can differentiate under appropriate in vitro and in vivo conditions into different cell types. Several groups have reported their ability to differentiate SCs into germline cells, and some of them have been ...
Rodrigues Patricia - - 2009
In the perinatal ovary of most mammals, external and internal factors establish a primordial follicle reserve that specifies the duration of the reproductive lifespan of a given species. We analyzed the mechanism of follicle loss and survival in C57BI/6 mice using static and dynamic assays of apoptosis, autophagy, and ovarian ...
Majhi S K - - 2009
Germ cell (GC) transplantation (GCT) is a novel reproductive technology with application in seed production and conservation of endangered species. This study examined the suitability of treatment with Busulfan, a cytotoxic agent, and warm water, known to cause GC degeneration, for depletion of endogenous GCs in sub-adult Patagonia pejerrey Odontesthes ...
Mishra Vivek - - 2009
Several incidences of reduction in the fertility (sperm count) have been reported in India and worldwide as well. Adulteration of food and consumption of adulterated mustard oil with argemone oil (AO) are presumed to be the factors for reduction in sperm count. In the present study we have studied the ...
Shaffer Meredith H MH Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, - - 2009
The highly homologous proteins ezrin, radixin, and moesin link proteins to the actin cytoskeleton. The two family members expressed in T cells, ezrin and moesin, are implicated in promoting T cell activation and polarity. To elucidate the contributions of ezrin and moesin, we conducted a systematic analysis of their function ...
Yoshioka Hirotaka - - 2009
In mice, male germ cells enter mitotic arrest beginning at 13.5 days postcoitum (dpc), and remain suspended in the G(0)/G(1) cell cycle stage until after birth. During this period, male germ cells undergo extensive epigenetic reprogramming, which is essential for their subsequent function as male gametes. A global reorganization and ...
Western Patrick - - 2009
The germ line is unique in that highly specialised cells must be formed while retaining genomic totipotency. In mice, germ cells are derived from the pluripotent epiblast cells under the influence of inductive signals. This specification event involves reactivation or maintenance of core regulators of pluripotency, activation of germ line ...
Roh Sangho - - 2009
Recent studies reported that the direct transformation of one differentiated somatic cell type into another is possible. In the present study, we were able to modulate the cell fate of somatic cells to take on male germ cell function by introducing cell extracts derived from porcine testis tissue. Fibroblasts were ...
Stiblar-Martincic D - - 2009
Apoptosis associated with programmed cell death plays an essential role in the control of germ cell number in the testes. Although male germ cell apoptosis has been well characterized in different animal models, only a few studies of apoptosis in human testes are presently available. In 43 infertile men with ...
Goel Sandeep - - 2009
Gonocytes are progenitor-type germ cells that arise from primordial germ cells and differentiate further into spermatogonia, thereby initiating spermatogenesis. In the present study, freshly isolated gonocytes were found to have either weak or no expression of pluripotency determining transcription factors, such as POU5F1, SOX2 and C-MYC. Interestingly, the expression of ...
Rago Vittoria - - 2009
BACKGROUND: Estrogens exert a role on germ cell physiology of normal human testis through the mediation of the estrogen receptor (ER) beta subtypes. Epidemiological studies evidenced an increased incidence of testicular germ cell cancer after elevated pre-natal estrogen exposure but the expression of estrogen receptors in these testicular neoplasms has ...
Augusto S C - - 2009
The nesting biology and the social structure of Euglossa fimbriata were studied based on two original nests found on the campus of the University of São Paulo, Ribeirão Preto, Brazil. Nest 1 contained two inseminated females, 39 sealed cells, one cell being provisioned, and six old and empty cells. Nest ...
Bucay Nathan - - 2009
Using human embryonic stem cells (hESCs), we describe a novel method for the rapid derivation and enrichment of cells that are comparable to primordial germ cells (PGCs) and Sertoli cells. The methodology described is based on modest changes to the growth conditions commonly used to expand hESCs and does not ...
Li Hui - - 2009
In mammals, germ cells within the developing gonad follow a sexually dimorphic pathway. Germ cells in the murine ovary enter meiotic prophase during embryogenesis, whereas germ cells in the embryonic testis arrest in G0 of mitotic cell cycle and do not enter meiosis until after birth. In mice, retinoic acid ...
Barchi Marco - - 2009
The studies of molecular events that occur in single cell types within a tissue often require the disaggregation of the tissue into a single cell suspension, followed by isolation of distinct cell populations. The germinal epithelium of mammals is composed of several cell types, which divide mitotically, before entering meiosis. ...
De Felici Massimo - - 2009
At the XIV Workshop on the Development and Function of the Reproductive Organs held at the Congress Centre of the University of Rome Tor Vergata, Monteporzio Catone, Rome, Italy, the introduction to the first session entitled Mammalian primordial germ cells dedicated to the memory of Anne McLaren, was the occasion ...
De Felici Massimo - - 2009
The XIV Workshop on the Development and Function of Reproductive Organs was held in Rome, from 14-17 September, 2008, at the Congress Centre of the University of Tor Vergata of Villa Mondragone (Rome, Italy). The Workshop was conceived to be a survey of the events from the formation of the ...
Sasso-Cerri Estela - - 2009
Cimetidine, refereed as antiandrogenic drug, causes hormonal changes in male patients such as increased testosterone and FSH levels. In the rat testis, structural alterations in the seminiferous tubules have been related to germ cell loss and Sertoli cell death by apoptosis. Regarding the important role of Sertoli cells in the ...
Linher Katja - - 2009
We have previously demonstrated that stem cells isolated from fetal porcine skin have the potential to form oocyte-like cells (OLCs) in vitro. However, primordial germ cells (PGCs), which must also be specified during the stem cell differentiation to give rise to these putative oocytes at more advanced stages of culture, ...
Wen Jing - - 2009
Partitioning-defective proteins (PAR) are detected to express mainly in the cytoplast, and play an important role in cell polarity. However, we showed here that PAR6, one kind of PAR protein, was localized in the nuclei of mouse oocytes that formed primordial follicles during the perinatal period, suggesting a new role ...
Deshpande Girish - - 2009
The isoprenoid biosynthetic pathway leading from the production of mevalonate by HMGCoA reductase (Hmgcr) to the geranylation of the G protein subunit, Ggamma1, plays an important role in cardiac development in the fly. Hmgcr has also been implicated in the release of the signaling molecule Hedgehog (Hh) from hh expressing ...
Yamauchi Kaori - - 2009
Mouse embryonic stem (ES) cells can differentiate into female and male germ cells in vitro. Primate ES cells can also differentiate into immature germ cells in vitro. However, little is known about the differentiation markers and culture conditions for in vitro germ cell differentiation from ES cells in primates. Monkey ...
Haston Kelly M - - 2009
Mammalian germ cells progress through a unique developmental program that encompasses proliferation and migration of the nascent primordial germ cell (PGC) population, reprogramming of nuclear DNA to reset imprinted gene expression, and differentiation of mature gametes. Little is known of the genes that regulate quantitative and qualitative aspects of early ...
Haag Eric S ES Department of Biology, University of Maryland, College Park, MD, - - 2009
A number of major adaptations in animals have been mediated by alteration of germ cells and their immediate derivatives, the gametes. Here, several such cases are discussed, including examples from echinoderms, vertebrates, insects, and nematodes. A feature of germ cells that make their development (and hence evolution) distinct from the ...
García-Alonso J - - 2009
The Spanish toothcarp Aphanius iberus is an endangered species which inhabits small rivers, creeks, salt marshes and marine salt pans in the Mediterranean coast of Spain. No differences in weights were observed among females or males taken from different environments. Analyses of the morphology of the gonads and the gametogenesis ...
Kilic Sevtap - - 2009
To investigate immunostaining pattern of caspase-3, an apoptosis marker, and vascular endothelial growth factor (VEGF), an hypoxia marker in testis biopsy specimens collected either from smoking or non-smoking patients with azoospermia. Testis biopsy specimens were obtained from thirty seven non-smoker and thirty eight smoker patients. Using immunochemistry technique, caspase-3 and ...
Ueno Hiroo - - 2009
During mouse development, primordial germ cells (PGCs) that give rise to the entire germ line are first identified within the proximal epiblast. However, long-term tracing of the fate of the cells has not been done wherein all cells in and around the germ-cell lineage are identified. Also, quantitative estimates of ...
Yanagimachi Ryuzo - - 2009
My interest in germ cells began when I first witnessed sea urchin fertilization and embryo development during a laboratory class at Hokkaido University, Sapporo, Japan, almost 60 yr ago. Weismann's concept of germ cells that I learned during my undergraduate years became the driving force of my entire research career. ...
Lin Yanfeng - - 2008
Retinoic acid (RA) is an essential extrinsic inducer of meiotic initiation in mammalian germ cells. However, RA acts too widely in mammalian development to account, by itself, for the cell-type and temporal specificity of meiotic initiation. We considered parallels to yeast, in which extrinsic and intrinsic factors combine to restrict ...
Ariz Mohd - - 2009
Maintenance of mitotically cycling germline stem cells (GSCs) is vital for continuous production of gametes. In worms and insects, signaling from surrounding somatic cells play an essential role in the maintenance of GSCs by preventing premature differentiation. In addition, germ cell proteins such as the Drosophila Pumilio and Caenorhabditis elegans ...
Chuva de Sousa Lopes Susana M - - 2008
In mouse embryos, the expression of Blimp1 has recently revealed a population of allocated primordial germ cell precursors 24 hours earlier than previously thought. Those 'blimped' precursors have been shown to give rise, by mitotic division, to germ cells only and no other cell lineages. Here, we try to understand ...
Yirme Galia - - 2008
The promise of human embryonic stem cells (hESCs) to provide an unlimited supply of cells for cell therapy depends on the availability of a controllable bioprocess for their expansion and differentiation. We describe here a robust and well-defined scale up platform for human embryoid body (EB) formation, propagation, and differentiation. ...
Cai Li-Yi - - 2009
HSV type 1 thymidine kinase (HSV1-TK)-introduced transgenic rodents and HSV-infected humans were reported to suffer male infertility. The present study aimed to find novel clues to clarify the cause of HSV1-TK-induced male infertility using an HSV1-tk transgenic rat line. Two truncated HSV1-TK proteins, 37 and 39kDa, were produced and accumulated ...
Haugland Thomas - - 2009
Sperm velocity has been shown to be a major determinant of fertilization success of external fertilizers. Yet, sperm velocity varies both within and between ejaculates and only a small number of fast sperm cells within an ejaculate are likely to have the potential of fertilizing the eggs. Having such fast ...
Sassone-Corsi Paolo - - 2008
The differentiation program of male germ cells in mammals is based on a sequence of cytological events that results in the formation of haploid spermatozoa from precursor stem cells. This process begins by mitotic division of germ-cell spermatogonia to give rise to diploid spermatocytes, which themselves replicate their DNA content, ...
Nagamori Ippei - - 2008
Differentiation of germ cells is characterized by a remarkable degree of cellular restructuring and gene regulation that involves complex events of genomic and epigenetic reorganization. The pathways that govern miRNAs have been shown to play an important role in the male germ cell lineage. The chromatoid body is a finely ...
Yoon, Christina Migyung, 1970-
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1997.
Kalia Sumiti - - 2008
Testicular germ cell apoptosis is normally a continuous process throughout life. However, massive testicular germ cell loss is known to result from a wide variety of cellular stresses including toxicant exposure. Thus, the present study was aimed to investigate the mechanisms of germ cell loss under stress conditions following diethyl ...
Kim Hyo Jung - - 2008
Flowering plants possess a unique reproductive strategy, involving double fertilization by twin sperm cells. Unlike animal germ lines, the male germ cell lineage in plants only forms after meiosis and involves asymmetric division of haploid microspores, to produce a large, non-germline vegetative cell and a germ cell that undergoes one ...
Grandi Gilberto - - 2008
Gonad development and sex differentiation from embryos to 594-day-old individuals were investigated in farmed Acipenser naccarii using light and transmission electron microscopy. The migrating primordial germ cells first appear along the dorsal wall of the body cavity in embryos 1.5 days before hatching. The gonadal ridge, containing a few primary ...
Tilgner Katarzyna - - 2008
Of all the cell types that can be obtained from the differentiation of embryonic stem cells, primordial germ cells are arguably the most fascinating, as they represent the in vitro completion of the reproductive cycle of the organism from which the embryonic stem cell line was derived. It is also ...
Anderson Ericka L - - 2008
In eukaryotes, diploid cells give rise to haploid cells via meiosis, a program of two cell divisions preceded by one round of DNA replication. Although key molecular components of the meiotic apparatus are highly conserved among eukaryotes, the mechanisms responsible for initiating the meiotic program have diverged substantially among eukaryotes. ...
Hattori Tomoko - - 2009
The neuropeptide arginine vasotocin (AVT) and its mammalian homologue arginine vasopressin (AVP) are believed to be involved in many social behaviors including territorial aggression. Testosterone (T) is also important for controlling territorial aggression, and it is believed to be involved in modulating AVT/AVP levels in the brain. In this study, ...
Macdonald Lindsay D - - 2008
Reproductive fitness in many animals relies upon a tight balance between the number of cells that proliferate in the germ line and the number of cells that enter meiosis and differentiate as gametes. In the Caenorhabditis elegans germ line, the GLP-1/Notch signaling pathway controls this balance between proliferation and meiotic ...
Sunanaga Takeshi - - 2008
We examined the structure, expression, and possible functions of a nanos homologue during gametogenesis and blastogenesis in the colonial ascidian Botryllus primigenus. An approximately 1.3-kb-long cDNA was cloned; it was termed BpNos since the deduced amino acid sequence (288 aa) contained 2 Nanos-like CCHC zinc finger motifs. Immature and mature ...
Schumacher Valérie - - 2008
Frasier syndrome (FS) is characterized by chronic renal failure in early adulthood, varying degrees of gonadal dysgenesis, and a high risk for gonadal germ cell malignancies, particularly gonadoblastoma. Although it is known to arise from heterozygous splice mutations in intron 9 of the Wilms' tumor gene 1 (WT1), the mechanisms ...
< 1 2 3 4 5 6 7 8 9 10 11 >