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1

Major derivatives of the ectoderm germ layer Primary neurulation: neural tube formation in the chick embryo (Part 1)  

E-print Network

in the chick embryo (Part 1) #12;Primary neurulation: neural tube formation in the chick embryo (Part 2) #12;Neurulation in an amphibian embryo, showing early, middle, and late neurulae in each case (Part 1) #12;Neurulation in an amphibian embryo, showing early, middle, and late neurulae in each case (Part 2) #12

2

Surgery in the management of primary intracranial germ cell tumors  

Microsoft Academic Search

Surgery plays an important part in the overall management of primary central nervous system (CNS) germ cell tumors. While\\u000a the general surgical objectives in patients with these neoplasms are similar to those with other types of CNS tumors, to obtain\\u000a an accurate histopathologic diagnosis and to contribute towards improving patient survival the unique features of germ cell\\u000a tumors have necessitated

Howard L. Weiner; Jonathan L. Finlay

1999-01-01

3

CT of primary germ-cell tumors of the mediastinum  

SciTech Connect

Primary mediastinal germ-cell tumors are rare neoplasms that usually occur in young men. Computed tomographic (CT) scans in four patients demonstrated large anterior mediastinal masses obliterating fat planes and extending inferiorly along the left mediastinal border. Nonseminomatous tumors contained areas of near-water density (cyst formation and/or necrosis) as well as soft-tissue density. Although CT features may suggest the diagnosis before histologic confirmation, the most important roles of CT are evaluation of extent of disease and monitoring response to therapy.

Levitt, R.G. (Mallinckrodt Inst. of Radiology, St.Louis, MO); Husband, J.E.; Glazer, H.S.

1984-01-01

4

Germ-Line Genetic Enhancement and Rawlsian Primary Goods  

Microsoft Academic Search

Genetic interventions raise a host of moral issues and, of its various species, germ-line genetic enhancement is the most morally contentious. This paper surveys various arguments against germ-line enhancement and attempts to demonstrate their inadequacies. A positive argument is advanced in favor of certain forms of germ-line enhancements, which holds that they are morally permissible if and only if they

Fritz Allhoff

2008-01-01

5

Germ-Line Genetic Enhancement and Rawlsian Primary Goods  

Microsoft Academic Search

Genetic interventions raise a host of moral issues and, of its various species, germ-line genetic enhancement is the most morally contentious. This paper surveys various arguments against germ-line enhancement and attempts to demonstrate their inadequacies. A positive argument is advanced in favor of cer- tain forms of germ-line enhancements, which holds that they are morally permis- sible if and only

Fritz Allhoff

2005-01-01

6

Germ layer specification and axial patterning in the embryonic development of the freshwater planarian Schmidtea polychroa.  

PubMed

Although patterning during regeneration in adult planarians has been studied extensively, very little is known about how the initial planarian body plan arises during embryogenesis. Herein, we analyze the process of embryo patterning in the species Schmidtea polychroa by comparing the expression of genes involved in the establishment of the metazoan body plan. Planarians present a derived ectolecithic spiralian development characterized by dispersed cleavage within a yolk syncytium and an early transient embryo capable of feeding on the maternally supplied yolk cells. During this stage of development, we only found evidence of canonical Wnt pathway, mostly associated with the development of its transient pharynx. At these stages, genes involved in gastrulation (snail) and germ layer determination (foxA and twist) are specifically expressed in migrating blastomeres and those giving rise to the temporary gut and pharyngeal muscle. After yolk ingestion, the embryo expresses core components of the canonical Wnt pathway and the BMP pathway, suggesting that the definitive axial identities are established late. These data support the division of planarian development into two separate morphogenetic stages: a highly divergent gastrulation stage, which segregates the three germ layers and establishes the primary organization of the feeding embryo; and subsequent metamorphosis, based on totipotent blastomeres, which establishes the definitive adult body plan using mechanisms that are similar to those used during regeneration and homeostasis in the adult. PMID:20100474

Martín-Durán, José María; Amaya, Enrique; Romero, Rafael

2010-04-01

7

Functions of Huntingtin in Germ Layer Specification and Organogenesis  

PubMed Central

Huntington’s disease (HD) is a neurodegenerative disease caused by abnormal polyglutamine expansion in the huntingtin protein (Htt). Although both Htt and the HD pathogenic mutation (mHtt) are implicated in early developmental events, their individual involvement has not been adequately explored. In order to better define the developmental functions and pathological consequences of the normal and mutant proteins, respectively, we employed embryonic stem cell (ESC) expansion, differentiation and induction experiments using huntingtin knock-out (KO) and mutant huntingtin knock-in (Q111) mouse ESC lines. In KO ESCs, we observed impairments in the spontaneous specification and survival of ectodermal and mesodermal lineages during embryoid body formation and under inductive conditions using retinoic acid and Wnt3A, respectively. Ablation of BAX improves cell survival, but failed to correct defects in germ layer specification. In addition, we observed ensuing impairments in the specification and maturation of neural, hepatic, pancreatic and cardiomyocyte lineages. These developmental deficits occurred in concert with alterations in Notch, Hes1 and STAT3 signaling pathways. Moreover, in Q111 ESCs, we observed differential developmental stage-specific alterations in lineage specification and maturation. We also observed changes in Notch/STAT3 expression and activation. Our observations underscore essential roles of Htt in the specification of ectoderm, endoderm and mesoderm, in the specification of neural and non-neural organ-specific lineages, as well as cell survival during early embryogenesis. Remarkably, these developmental events are differentially deregulated by mHtt, raising the possibility that HD-associated early developmental impairments may contribute not only to region-specific neurodegeneration, but also to non-neural co-morbidities. PMID:23967334

Nguyen, Giang D.; Molero, Aldrin E.; Gokhan, Solen; Mehler, Mark F.

2013-01-01

8

Primary intrasellar mixed germ-cell tumor with precocious puberty and diabetes insipidus  

Microsoft Academic Search

We report an 8-year-old boy with a primary intrasellar mixed germ-cell tumor who underwent the trans-sphenoidal approach for\\u000a tumor removal. Initially he suffered from diabetes insipidus. Precocious puberty and left abducens nerve palsy were also observed.\\u000a Elevation of serum testosterone, ?-human chorionic gonadotropin (HCG), and ?-fetoprotein (AFP) were found on admission. The histological study revealed mixed cellular types of tumor

Der-Yang Cho; Yeou-Chih Wang; Willam-Lin Ho

1997-01-01

9

Origin of germ cells and formation of new primary follicles in adult human ovaries  

PubMed Central

Recent reports indicate that functional mouse oocytes and sperm can be derived in vitro from somatic cell lines. We hypothesize that in adult human ovaries, mesenchymal cells in the tunica albuginea (TA) are bipotent progenitors with a commitment for both primitive granulosa and germ cells. We investigated ovaries of twelve adult women (mean age 32.8 ± 4.1 SD, range 27–38 years) by single, double, and triple color immunohistochemistry. We show that cytokeratin (CK)+ mesenchymal cells in ovarian TA differentiate into surface epithelium (SE) cells by a mesenchymal-epithelial transition. Segments of SE directly associated with ovarian cortex are overgrown by TA, forming solid epithelial cords, which fragment into small (20 micron) epithelial nests descending into the lower ovarian cortex, before assembling with zona pellucida (ZP)+ oocytes. Germ cells can originate from SE cells which cover the TA. Small (10 micron) germ-like cells showing PS1 meiotically expressed oocyte carbohydrate protein are derived from SE cells via asymmetric division. They show nuclear MAPK immunoexpression, subsequently divide symmetrically, and enter adjacent cortical vessels. During vascular transport, the putative germ cells increase to oocyte size, and are picked-up by epithelial nests associated with the vessels. During follicle formation, extensions of granulosa cells enter the oocyte cytoplasm, forming a single paranuclear CK+ Balbiani body supplying all the mitochondria of the oocyte. In the ovarian medulla, occasional vessels show an accumulation of ZP+ oocytes (25–30 microns) or their remnants, suggesting that some oocytes degenerate. In contrast to males, adult human female gonads do not preserve germline type stem cells. This study expands our previous observations on the formation of germ cells in adult human ovaries. Differentiation of primitive granulosa and germ cells from the bipotent mesenchymal cell precursors of TA in adult human ovaries represents a most sophisticated adaptive mechanism created during the evolution of female reproduction. Our data indicate that the pool of primary follicles in adult human ovaries does not represent a static but a dynamic population of differentiating and regressing structures. An essential mission of such follicular turnover might be elimination of spontaneous or environmentally induced genetic alterations of oocytes in resting primary follicles. PMID:15115550

Bukovsky, Antonin; Caudle, Michael R; Svetlikova, Marta; Upadhyaya, Nirmala B

2004-01-01

10

Primary Spinal Germ Cell Tumors: A Case Analysis and Review of Treatment Paradigms  

PubMed Central

Objective. Primary intramedullary spinal germ cell tumors are exceedingly rare. As such, there are no established treatment paradigms. We describe our management for spinal germ cell tumors and a review of the literature. Clinical Presentation. We describe the case of a 45-year-old man with progressive lower extremity weakness and sensory deficits. He was found to have enhancing intramedullary mass lesions in the thoracic spinal cord, and pathology was consistent with an intramedullary germ cell tumor. A video presentation of the case and surgical approach is provided. Conclusion. As spinal cord germinomas are highly sensitive to radiation and chemotherapy, a patient can be spared radical surgery. Diverse treatment approaches exist across institutions. We advocate biopsy followed by local radiation, with or without adjuvant chemotherapy, as the optimal treatment for these tumors. Histological findings have prognostic value if syncytiotrophoblastic giant cells (STGCs) are found, which are associated with a higher rate of recurrence. The recurrence rate in STGC-positive spinal germinomas is 33% (2/6), whereas it is only 8% in STGC-negative tumors (2/24). We advocate limited volume radiotherapy combined with systemic chemotherapy in patients with high risk of recurrence. To reduce endocrine and neurocognitive side effects, cranio-spinal radiation should be used as a last resort in patients with recurrence. PMID:24312128

Loya, Joshua J.; Jung, Henry; Temmins, Caroline; Cho, Nam; Singh, Harminder

2013-01-01

11

Clinicopathological and immunohistochemical features of primary central nervous system germ cell tumors: a 24-years experience  

PubMed Central

Primary central nervous system (CNS) germ cell tumors (GCTs) are a rare heterogeneous group of lesions, which the clinicopathological features have a marked degree of heterogeneity comparing with that of gonadal GCTs. Accurately diagnosing CNS GCTs might be extremely difficult and requires immunohistochemical verification. This study was to investigate the biological feature of CNS GCTs and diagnostic value of immunohistochemical markers OCT3/4, C-kit, PLAP, and CD30 in CNS GCTs. A retrospective study was performed on 34 patients with CNS germ cell tumors between 1990 and 2014. 34 CNS GCTs account for 9.2% of all primary CNS neoplasms. The sellar region (35.3%) and pineal gland (17.6%) were the most common sites of intracranial GCTs. Hydrocephalus (82.4%) and diplopia (46.9%) were the two most common clinical presentations. The most common histological subtypes were germinoma (67.6%). PLAP, c-kit, OCT3/4 were highly expressed in gernimomas. CD30 and CK AE1/3 stainings were positive in embryonal carcinoma. Yolk sac tumor component showed positive staining for AFP and CK AE1/3. ?-HCG staining was positive in choriocarcinoma and STGC. Patients with mature teratomas and germinomas had a better prognosis (a 5-year survival rate) than those with embryonal carcinoma and choriocarcinoma (a 5-year survival rates were 0). Our finding suggest that the incidences of primary CNS GCTs are higher in South China than in the West, but mixed GCTs are uncommon in our study. The judicious use of a panel of selected markers is helpful in diagnosing and predicting the prognosis for CNS GCTs. PMID:25400782

Gao, Yuping; Jiang, Jiyao; Liu, Qiang

2014-01-01

12

EphrinB/EphB Signaling Controls Embryonic Germ Layer Separation by Contact-Induced Cell Detachment  

PubMed Central

Background The primordial organization of the metazoan body is achieved during gastrulation by the establishment of the germ layers. Adhesion differences between ectoderm, mesoderm, and endoderm cells could in principle be sufficient to maintain germ layer integrity and prevent intermixing. However, in organisms as diverse as fly, fish, or amphibian, the ectoderm-mesoderm boundary not only keeps these germ layers separated, but the ectoderm also serves as substratum for mesoderm migration, and the boundary must be compatible with repeated cell attachment and detachment. Principal Findings We show that localized detachment resulting from contact-induced signals at the boundary is at the core of ectoderm-mesoderm segregation. Cells alternate between adhesion and detachment, and detachment requires ephrinB/EphB signaling. Multiple ephrinB ligands and EphB receptors are expressed on each side of the boundary, and tissue separation depends on forward signaling across the boundary in both directions, involving partially redundant ligands and receptors and activation of Rac and RhoA. Conclusion This mechanism differs from a simple differential adhesion process of germ layer formation. Instead, it involves localized responses to signals exchanged at the tissue boundary and an attachment/detachment cycle which allows for cell migration across a cellular substratum. PMID:21390298

Rohani, Nazanin; Canty, Laura; Luu, Olivia

2011-01-01

13

Evolution of Developmental Control Mechanisms Germ layer specification and axial patterning in the embryonic development of the  

E-print Network

Regeneration Although patterning during regeneration in adult planarians has been studied extensively, very in the embryonic development of the freshwater planarian Schmidtea polychroa José María Martín-Durán a, , Enrique Available online 25 January 2010 Keywords: Planarian Embryo Patterning Gastrulation Germ layers Polarity

Amaya, Enrique

14

Primary malignant mediastinal germ cell tumours: improved prognosis with platinum-based chemotherapy and surgery.  

PubMed Central

A retrospective analysis was performed of 18 patients with primary malignant germ cell tumours of the mediastinum treated with platinum-based chemotherapy between 1977 and 1990. All seven patients with pure seminoma were treated initially with chemotherapy and four of these patients received additional mediastinal radiotherapy. Only one patient relapsed; his initial therapy had included radiotherapy and single-agent carboplatin and he was successfully salvaged with combination chemotherapy. With a follow-up of 11 to 117 months (median 41 months) all seven patients with seminoma remain alive and disease free giving an overall survival of 100%. Eleven patients had malignant non seminoma; following chemotherapy eight of these had elective surgical resection of residual mediastinal masses. Complete remission was achieved in nine (82%) patients, however, one of these patients died from bleomycin pneumonitis. With a follow-up of 12 to 113 months (median 55 months) eight of 11 (73%) patients with malignant mediastinal teratoma remain alive and disease free. PMID:8494705

Childs, W. J.; Goldstraw, P.; Nicholls, J. E.; Dearnaley, D. P.; Horwich, A.

1993-01-01

15

Germ cells are not the primary factor for sexual fate determination in goldfish.  

PubMed

The presence of germ cells in the early gonad is important for sexual fate determination and gonadal development in vertebrates. Recent studies in zebrafish and medaka have shown that a lack of germ cells in the early gonad induces sex reversal in favor of a male phenotype. However, it is uncertain whether the gonadal somatic cells or the germ cells are predominant in determining gonadal fate in other vertebrate. Here, we investigated the role of germ cells in gonadal differentiation in goldfish, a gonochoristic species that possesses an XX-XY genetic sex determination system. The primordial germ cells (PGCs) of the fish were eliminated during embryogenesis by injection of a morpholino oligonucleotide against the dead end gene. Fish without germ cells showed two types of gonadal morphology: one with an ovarian cavity; the other with seminiferous tubules. Next, we tested whether function could be restored to these empty gonads by transplantation of a single PGC into each embryo, and also determined the gonadal sex of the resulting germline chimeras. Transplantation of a single GFP-labeled PGC successfully produced a germline chimera in 42.7% of the embryos. Some of the adult germline chimeras had a developed gonad on one side that contained donor derived germ cells, while the contralateral gonad lacked any early germ cell stages. Female germline chimeras possessed a normal ovary and a germ-cell free ovary-like structure on the contralateral side; this structure was similar to those seen in female morphants. Male germline chimeras possessed a testis and a contralateral empty testis that contained some sperm in the tubular lumens. Analysis of aromatase, foxl2 and amh expression in gonads of morphants and germline chimeras suggested that somatic transdifferentiation did not occur. The offspring of fertile germline chimeras all had the donor-derived phenotype, indicating that germline replacement had occurred and that the transplanted PGC had rescued both female and male gonadal function. These findings suggest that the absence of germ cells did not affect the pathway for ovary or testis development and that phenotypic sex in goldfish is determined by somatic cells under genetic sex control rather than an interaction between the germ cells and somatic cells. PMID:22824426

Goto, Rie; Saito, Taiju; Takeda, Takahiro; Fujimoto, Takafumi; Takagi, Misae; Arai, Katsutoshi; Yamaha, Etsuto

2012-10-01

16

Symmetry breaking, germ layer specification and axial organisation in aggregates of mouse embryonic stem cells  

PubMed Central

Mouse embryonic stem cells (mESCs) are clonal populations derived from preimplantation mouse embryos that can be propagated in vitro and, when placed into blastocysts, contribute to all tissues of the embryo and integrate into the normal morphogenetic processes, i.e. they are pluripotent. However, although they can be steered to differentiate in vitro into all cell types of the organism, they cannot organise themselves into structures that resemble embryos. When aggregated into embryoid bodies they develop disorganised masses of different cell types with little spatial coherence. An exception to this rule is the emergence of retinas and anterior cortex-like structures under minimal culture conditions. These structures emerge from the cultures without any axial organisation. Here, we report that small aggregates of mESCs, of about 300 cells, self-organise into polarised structures that exhibit collective behaviours reminiscent of those that cells exhibit in early mouse embryos, including symmetry breaking, axial organisation, germ layer specification and cell behaviour, as well as axis elongation. The responses are signal specific and uncouple processes that in the embryo are tightly associated, such as specification of the anteroposterior axis and anterior neural development, or endoderm specification and axial elongation. We discuss the meaning and implications of these observations and the potential uses of these structures which, because of their behaviour, we suggest to call ‘gastruloids’. PMID:25371360

van den Brink, Susanne C.; Baillie-Johnson, Peter; Balayo, Tina; Hadjantonakis, Anna-Katerina; Nowotschin, Sonja; Turner, David A.; Martinez Arias, Alfonso

2014-01-01

17

An ancient role for nuclear beta-catenin in the evolution of axial polarity and germ layer segregation  

NASA Technical Reports Server (NTRS)

The human oncogene beta-catenin is a bifunctional protein with critical roles in both cell adhesion and transcriptional regulation in the Wnt pathway. Wnt/beta-catenin signalling has been implicated in developmental processes as diverse as elaboration of embryonic polarity, formation of germ layers, neural patterning, spindle orientation and gap junction communication, but the ancestral function of beta-catenin remains unclear. In many animal embryos, activation of beta-catenin signalling occurs in blastomeres that mark the site of gastrulation and endomesoderm formation, raising the possibility that asymmetric activation of beta-catenin signalling specified embryonic polarity and segregated germ layers in the common ancestor of bilaterally symmetrical animals. To test whether nuclear translocation of beta-catenin is involved in axial identity and/or germ layer formation in 'pre-bilaterians', we examined the in vivo distribution, stability and function of beta-catenin protein in embryos of the sea anemone Nematostella vectensis (Cnidaria, Anthozoa). Here we show that N. vectensis beta-catenin is differentially stabilized along the oral-aboral axis, translocated into nuclei in cells at the site of gastrulation and used to specify entoderm, indicating an evolutionarily ancient role for this protein in early pattern formation.

Wikramanayake, Athula H.; Hong, Melanie; Lee, Patricia N.; Pang, Kevin; Byrum, Christine A.; Bince, Joanna M.; Xu, Ronghui; Martindale, Mark Q.

2003-01-01

18

Null Association Between Histology of First and Second Primary Malignancies in Men With Bilateral Testicular Germ Cell Tumors  

PubMed Central

Testicular germ cell tumors (TGCTs), the most common neoplasms of young men, are categorized histologically as either seminomas or nonseminomas/mixed germ cell tumors. These subtypes differ by age at diagnosis and clinical course, but little is known about etiological distinctions. To test the hypothesis that histological subtypes have distinct sets of unrecognized etiological factors, we used a recently described approach, estimating the association between histological types of first and second tumors of men with 2 primary TGCTs. The study population of 488 men each with 2 primary TGCTs was ascertained through population-based cancer registries in the United States between 1972 and 2006. Univariate logistic regression analysis revealed that the histology of second primary TGCTs was associated with the histology of first TGCTs (odds ratio = 1.70, 95% confidence interval: 1.14, 2.52); however, the association did not persist in analyses adjusted for age at diagnosis of first TGCT (odds ratio = 1.09, 95% confidence interval: 0.71, 1.70). These results would be expected if the subtypes share etiology but experience different rates of progression to diagnosis or if the histological fate of TGCTs is influenced by age-related processes. Men with 2 primary TGCTs provide novel opportunities to learn whether histological subtypes are likely to share etiology, so results may inform research designed to identify causes. PMID:23928263

Thomas, Jennifer Phay Johnson; Davis-Dao, Carol; Lewinger, Juan Pablo; Siegmund, Kimberly D.; Hamilton, Ann S.; Daneshmand, Siamak; Skinner, Eila C.; Thomas, Duncan C.; Cortessis, Victoria K.

2013-01-01

19

True Malignant Histiocytosis with Trisomy 9 following Primary Mediastinal Germ Cell Tumor  

Microsoft Academic Search

A 24-year-old Japanese man was admitted due to bloody phlegm in May 2002. A diagnosis of mediastinal germ cell tumor, mixed type involving seminoma, immature teratoma and embryonal carcinoma, was made by transthoracic needle biopsy. Three months later, his complete blood counts revealed pancytopenia with high fever. Examination of bone marrow revealed increased atypical large histiocytes (5.6%) with hemophagocytosis, and

Mitsuhiro Suenaga; Kakushi Matsushita; Nakaaki Kawamata; Toshimasa Kukita; Yuji Hamakawa; Kentaro Gejima; Reiri Onodera; Tetsuo Sato; Akihiko Yamaguchi; Hirosaka Inoue; Kosei Arimura; Naomichi Arima; Hiroki Yoshida; Chuwa Tei

2006-01-01

20

Primary Germ Cell Tumor of the Mediastinum - Presenting as a Huge Mass  

PubMed Central

Germ cell tumors compromise 15-20% of all anterior mediastinal masses; 50-60% of these are benign mediastinal teratoma. There may be mature, immature, and rarely with malignant component within the tumor mass. There are more chances of malignancy with immature type. We are reporting a case in 20-year young male diagnosed as giant benign cystic teratoma which was adherent to superior vena cava. The patient underwent surgical excision. In follow up of 2 years, the patient is not having any complaints. PMID:24627752

Dalal, Usha; Jora, Manjit Singh; Dalal, Ashwani K.; Attri, Ashok K.; Singal, Rikki; Gupta, Samita

2014-01-01

21

Variation in the Dorsal gradient distribution is a source for modified scaling of germ layers in Drosophila  

PubMed Central

Specification of germ layers along the dorso-ventral (DV) axis by morphogenetic gradients is an ideal model to study scaling properties of gradients and cell fate changes during evolution. Classical anatomical studies in divergent insects (e.g. flies and grasshopper) revealed that the neuroectodermal size is conserved and originates similar numbers of neuroblasts of homologous identity [1-3]. In contrast, mesodermal domains vary significantly in closely related Drosophila species [4]. To further investigate the underlying mechanisms of scaling of germ layers across Drosophila species, we quantified the Dorsal (Dl)/NFk-B gradient, the main morphogenetic gradient that initiates separation of the mesoderm, neuroectoderm and ectoderm [5-7]. We discovered a variable range of Toll activation across species and that Dl activates mesodermal genes at same threshold levels in melanogaster sibling species. We also show that the Dl gradient distribution can be modulated by nuclear size and packing densities. We propose that variation in mesodermal size occurs at a fast evolutionary rate and is an important mechanism to define the ventral boundary of the neuroectoderm. PMID:23583556

Chahda, Juan Sebastian; Sousa-Neves, Rui; Mizutani, Claudia Mieko

2013-01-01

22

Transcriptional profiling of endogenous germ layer precursor cells identifies dusp4 as an essential gene in zebrafish endoderm specification.  

PubMed

A major goal for developmental biologists is to define the behaviors and molecular contents of differentiating cells. We have devised a strategy for isolating cells from diverse embryonic regions and stages in the zebrafish, using computer-guided laser photoconversion of injected Kaede protein and flow cytometry. This strategy enabled us to perform a genome-wide transcriptome comparison of germ layer precursor cells. Mesendoderm and ectoderm precursors cells isolated by this method differentiated appropriately in transplantation assays. Microarray analysis of these cells reidentified known genes at least as efficiently as previously reported strategies that relied on artificial mesendoderm activation or inhibition. We also identified a large set of uncharacterized mesendoderm-enriched genes as well as ectoderm-enriched genes. Loss-of-function studies revealed that one of these genes, the MAP kinase inhibitor dusp4, is essential for early development. Embryos injected with antisense morpholino oligonucleotides that targeted Dusp4 displayed necrosis of head tissues. Marker analysis during late gastrulation revealed a specific loss of sox17, but not of other endoderm markers, and analysis at later stages revealed a loss of foregut and pancreatic endoderm. This specific loss of sox17 establishes a new class of endoderm specification defect. PMID:18719100

Brown, Jamie L; Snir, Mirit; Noushmehr, Houtan; Kirby, Martha; Hong, Sung-Kook; Elkahloun, Abdel G; Feldman, Benjamin

2008-08-26

23

Repression of nodal expression by maternal B1-type SOXs regulates germ layer formation in Xenopus and zebrafish.  

PubMed

B1-type SOXs (SOXs 1, 2, and 3) are the most evolutionarily conserved subgroup of the SOX transcription factor family. To study their maternal functions, we used the affinity-purified antibody antiSOX3c, which inhibits the binding of Xenopus SOX3 to target DNA sequences [Development. 130(2003)5609]. The antibody also cross-reacts with zebrafish embryos. When injected into fertilized Xenopus or zebrafish eggs, antiSOX3c caused a profound gastrulation defect; this defect could be rescued by the injection of RNA encoding SOX3DeltaC-EnR, a SOX3-engrailed repression domain chimera. In antiSOX3c-injected Xenopus embryos, normal animal-vegetal patterning of mesodermal and endodermal markers was disrupted, expression domains were shifted toward the animal pole, and the levels of the endodermal markers SOX17 and endodermin increased. In Xenopus, SOX3 acts as a negative regulator of Xnr5, which encodes a nodal-related TGFbeta-family protein. Two nodal-related proteins are expressed in the early zebrafish embryo, squint and cyclops; antiSOX3c-injection leads to an increase in the level of cyclops expression. In both Xenopus and zebrafish, the antiSOX3c phenotype was rescued by the injection of RNA encoding the nodal inhibitor Cerberus-short (CerS). In Xenopus, antiSOX3c's effects on endodermin expression were suppressed by injection of RNA encoding a dominant negative version of Mixer or a morpholino against SOX17alpha2, both of which act downstream of nodal signaling in the endoderm specification pathway. Based on these data, it appears that maternal B1-type SOX functions together with the VegT/beta-catenin system to regulate nodal expression and to establish the normal pattern of germ layer formation in Xenopus. A mechanistically conserved system appears to act in a similar manner in the zebrafish. PMID:15302595

Zhang, Chi; Basta, Tamara; Hernandez-Lagunas, Laura; Simpson, Peter; Stemple, Derek L; Artinger, Kristin B; Klymkowsky, Michael W

2004-09-01

24

Germ Tag  

NSDL National Science Digital Library

In this version of tag, a large group of learners model how the body fights infection. Learners act as germs, as lymphocytes, and as the body's cells threatened by germs. After playing one round, subsequent rounds can use different numbers of germs and/or lymphocytes to see how the infection rate is changed. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. They can also keep track of their progress in all of the Kinetic City activities, and compare their progress to other participants worldwide.

Science, American A.

2009-01-01

25

Non-primary layering in some Adirondack orthogneisses  

SciTech Connect

Metamorphic, as opposed to primary, layering has been shown to be important in many tectonites. Within orthogneisses additional types of non-primary layering are common and have important genetic implications. Here the authors cite three Adirondack examples. (1) Hyde School Gneiss of the Adirondack Lowlands contains semi-continuous layers of foliated amphibolite arranged parallel to contacts and early foliation and disrupted by pegmatitic, alaskitic, and tonalitic host rock. Layering appears to be the result of penetration of amphibolite by granitoid magma first along extensional fractures and then parallel to foliation. Intrusion is envisaged to take place in active shear zones initially occupied by foliated amphibolite that is subsequently penetrated parallel to foliation by granitoids. (2) South of Elizabethtown foliated, isoclinally folded gabbroic anorthosite is well layered with garnetiferous amphibolite, quartz-feldspar gneiss, and calcsilicate. Because of rock composition, the layering cannot be due to metavolcanic sequences nor can disruption be attributed to partial melting. A satisfactory interpretation is that gabbroic anorthosite intruded mafic and carbonate-rich rocks in lit-par-lit fashion. (3) North of Speculator a garnetiferous amphibolite/gabbro has been intruded by granite now containing xenoliths, some with ophitic opx. Much of the layering in the granite consists of clots of plagioclase, garnet, pyroxene (chloritized) arranged in parallel. These are interpreted as small xenoliths of garnetiferous amphibolite/gabbro entrained into the granitic magma and strung out in the direction of flow. These examples provide further evidence that layering can develop during magmatic emplacement and need not represent primary stratification. Assignment of a primary origin to such layering necessarily results in misinterpretation of geologic history.

Levy, R.; McLelland, J.; Ritter, A. (Colgate Univ., Hamilton, NY (United States). Geology Dept.)

1993-03-01

26

Trainee Primary Teachers' Ideas about the Ozone Layer.  

ERIC Educational Resources Information Center

Survey results reveal trainee primary teachers are well informed about the nature and location of the ozone layer and appreciated that it screens the earth from ultraviolet (UV) rays, although some thought that it protects the earth from acid rain. Identifies themes in students' thinking and groups of students with different concepts. (LZ)

Boyes, Edward; And Others

1995-01-01

27

DNA Methylation Is the Primary Silencing Mechanism for a Set of Germ Line- and Tumor-Specific Genes with a CpG-Rich Promoter  

PubMed Central

A subset of male germ line-specific genes, the MAGE-type genes, are activated in many human tumors, where they produce tumor-specific antigens recognized by cytolytic T lymphocytes. Previous studies on gene MAGE-A1 indicated that transcription factors regulating its expression are present in all tumor cell lines whether or not they express the gene. The analysis of two CpG sites located in the promoter showed a strong correlation between expression and demethylation. It was also shown that MAGE-A1 transcription was induced in cell cultures treated with demethylating agent 5?-aza-2?-deoxycytidine. We have now analyzed all of the CpG sites within the 5? region of MAGE-A1 and show that for all of them, demethylation correlates with the transcription of the gene. We also show that the induction of MAGE-A1 with 5?-aza-2?-deoxycytidine is stable and that in all the cell clones it correlates with demethylation, indicating that demethylation is necessary and sufficient to produce expression. Conversely, transfection experiments with in vitro-methylated MAGE-A1 sequences indicated that heavy methylation suffices to stably repress the gene in cells containing the transcription factors required for expression. Most MAGE-type genes were found to have promoters with a high CpG content. Remarkably, although CpG-rich promoters are classically unmethylated in all normal tissues, those of MAGE-A1 and LAGE-1 were highly methylated in somatic tissues. In contrast, they were largely unmethylated in male germ cells. We conclude that MAGE-type genes belong to a unique subset of germ line-specific genes that use DNA methylation as a primary silencing mechanism. PMID:10523621

De Smet, Charles; Lurquin, Christophe; Lethé, Bernard; Martelange, Valérie; Boon, Thierry

1999-01-01

28

SOX9 accelerates ESC differentiation to three germ layer lineages by repressing SOX2 expression through P21 (WAF1/CIP1).  

PubMed

Upon removal of culture conditions that maintain an undifferentiated state, mouse embryonic stem cells (ESCs) differentiate into various cell types. Differentiation can be facilitated by forced expression of certain transcription factors (TFs), each of which can generally specify a particular developmental lineage. We previously established 137 mouse ESC lines, each of which carried a doxycycline-controllable TF. Among them, Sox9 has unique capacity: its forced expression accelerates differentiation of mouse ESCs into cells of all three germ layers. With the additional use of specific culture conditions, overexpression of Sox9 facilitated the generation of endothelial cells, hepatocytes and neurons from ESCs. Furthermore, Sox9 action increases formation of p21 (WAF1/CIP1), which then binds to the SRR2 enhancer of pluripotency marker Sox2 and inhibits its expression. Knockdown of p21 abolishes inhibition of Sox2 and Sox9-accelerated differentiation, and reduction of Sox2 2 days after the beginning of ESC differentiation can comparably accelerate mouse ESC formation of cells of three germ layers. These data implicate the involvement of the p21-Sox2 pathway in the mechanism of accelerated ESC differentiation by Sox9 overexpression. The molecular cascade could be among the first steps to program ESC differentiation. PMID:25371362

Yamamizu, Kohei; Schlessinger, David; Ko, Minoru S H

2014-11-01

29

A case of primary testicular germ cell tumor with rhabdomyosarcoma metastases as an example of applying the FISH method to diagnostic pathology.  

PubMed

We present the interesting case of a 38-year-old man with a primary malignant tumor of the right testis that metachronously metastasized to the urinary bladder and the stomach. Histologically, the testicular tumor was a mixed germ cell tumor composed of teratoma and embryonal carcinoma, but it also contained a sarcoma component of somatic type malignancy. Metastases showed rhabdomyoblastic differentiation histologically identical to the sarcoma component of the testicular tumor that was diagnosed as rhabdomyosarcoma. By applying fluorescence in situ hybridization (FISH) to the cytogenetic examination of cells taken from the periventricular lymph node metastases, we demonstrated a structural chromosomal aberration characteristic of testicular neoplasms, i.e. the presence of isochromosome 12p (i(12p)). Additionally, the diagnosis was supported by immunohistochemistry. PMID:18092964

Korski, Konstanty; Breborowicz, Danuta; Filas, Violetta; Breborowicz, Jan; Grygalewicz, Beata; Pienkowska-Grela, Barbara

2007-11-01

30

Pediatric primary central nervous system germ cell tumors of different prognosis groups show characteristic miRNome traits and chromosome copy number variations  

PubMed Central

Background Intracranial pediatric germ cell tumors (GCTs) are rare and heterogeneous neoplasms and vary in histological differentiation, prognosis and clinical behavior. Germinoma and mature teratoma are GCTs that have a good prognosis, while other types of GCTs, termed nongerminomatous malignant germ cell tumors (NGMGCTs), are tumors with an intermediate or poor prognosis. The second group of tumors requires more extensive drug and irradiation treatment regimens. The mechanisms underlying the differences in incidence and prognosis of the various GCT subgroups are unclear. Results We identified a distinct mRNA profile correlating with GCT histological differentiation and prognosis, and also present in this study the first miRNA profile of pediatric primary intracranial GCTs. Most of the differentially expressed miRNAs were downregulated in germinomas, but miR-142-5p and miR-146a were upregulated. Genes responsible for self-renewal (such as POU5F1 (OCT4), NANOG and KLF4) and the immune response were abundant in germinomas, while genes associated with neuron differentiation, Wnt/?-catenin pathway, invasiveness and epithelial-mesenchymal transition (including SNAI2 (SLUG) and TWIST2) were abundant in NGMGCTs. Clear transcriptome segregation based on patient survival was observed, with malignant NGMGCTs being closest to embryonic stem cells. Chromosome copy number variations (CNVs) at cytobands 4q13.3-4q28.3 and 9p11.2-9q13 correlated with GCT malignancy and clinical risk. Six genes (BANK1, CXCL9, CXCL11, DDIT4L, ELOVL6 and HERC5) within 4q13.3-4q28.3 were more abundant in germinomas. Conclusions Our results integrate molecular profiles with clinical observations and provide insights into the underlying mechanisms causing GCT malignancy. The genes, pathways and microRNAs identified have the potential to be novel therapeutic targets. PMID:20178649

2010-01-01

31

Germ Cell Differentiation from Pluripotent Cells  

PubMed Central

Infertility is a medical condition with an increasing impact in Western societies with causes linked to toxins, genetics, and aging (primarily delay of motherhood). Within the different pathologies that can lead to infertility, poor quality or reduced quantity of gametes plays an important role. Gamete donation and therefore demand on donated sperm and eggs in fertility clinics is increasing. It is hoped that a better understanding of the conditions related to poor gamete quality may allow scientists to design rational treatments. However, to date, relatively little is known about human germ cell development in large part due to the inaccessibility of human development to molecular genetic analysis. It is hoped that pluripotent human embryonic stem cells and induced pluripotent stem cells may provide an accessible in vitro model to study germline development; these cells are able to differentiate to cells of all three primary embryonic germ layers, as well as to germ cells in vitro. We review the state of the art in germline differentiation from pluripotent stem cells. PMID:23329632

Medrano, Jose V.; Pera, Renee A. Reijo; Simón, Carlos

2014-01-01

32

Blastema cells derived from New Zealand white rabbit's pinna carry stemness properties as shown by differentiation into insulin producing, neural, and osteogenic lineages representing three embryonic germ layers.  

PubMed

Stem cells (SCs) are known as undifferentiated cells with self-renewal and differentiation capacities. Regeneration is a phenomenon that occurs in a limited number of animals after injury, during which blastema tissue is formed. It has been hypothesized that upon injury, the dedifferentiation of surrounding tissues leads into the appearance of cells with SC characteristics. In present study, stem-like cells (SLCs) were obtained from regenerating tissue of New Zealand white rabbit's pinna and their stemness properties were examined by their capacity to differentiate toward insulin producing cells (IPCs), as well as neural and osteogenic lineages. Differentiation was induced by culture of SLCs in defined medium, and cell fates were monitored by specific staining, RT-PCR and flow cytometry assays. Our results revealed that dithizone positive cells, which represent IPCs, and islet-like structures appeared 1 week after induction of SLCs, and this observation was confirmed by the elevated expression of Ins, Pax6 and Glut4 at mRNA level. Furthermore, SLCs were able to express neural markers as early as 1 week after retinoic acid treatment. Finally, SLCs were able to differentiate into osteogenic lineage, as confirmed by Alizarin Red S staining and RT-PCR studies. In conclusion, SLCs, which could successfully differentiate into cells derived from all three germ layers, can be considered as a valuable model to study developmental biology and regenerative medicine. PMID:25371011

Saeinasab, Morvarid; Matin, Maryam M; Rassouli, Fatemeh B; Bahrami, Ahmad Reza

2014-11-01

33

Human Mesenchymal Stem Cells Derived From Limb Bud Can Differentiate into All Three Embryonic Germ Layers Lineages  

PubMed Central

Abstract Mesenchymal stem cells (MSCs) have been isolated from many sources, including adults and fetuses. Previous studies have demonstrated that, compared with their adult counterpart, fetal MSCs with several remarkable advantages may be a better resource for clinical applications. In this study, we successfully isolated a rapidly proliferating cell population from limb bud of aborted fetus and termed them “human limb bud–derived mesenchymal stem cells” (hLB-MSCs). Characteristics of their morphology, phenotype, cell cycle, and differentiation properties were analyzed. These adherent cell populations have a typically spindle-shaped morphology. Flow cytometry analysis showed that hLB-MSCs are positive for CD13, CD29, CD90, CD105, and CD106, but negative for CD3, CD4, CD5, CD11b, CD14, CD15, CD34, CD45, CD45RA, and HLA-DR. The detection of cell cycle from different passages indicated that hLB-MSCs have a similar potential for propagation during long culture in vitro. The most novel finding here is that, in addition to their mesodermal differentiation (osteoblasts and adipocytes), hLB-MSCs can also differentiated into extramesenchymal lineages, such as neural (ectoderm) and hepatic (endoderm) progenies. These results indicate that hLB-MSCs have a high level of plasticity and can differentiate into cell lineages from all three embryonic layers in vitro. PMID:22775353

Jiao, Fei; Wang, Juan; Dong, Zhao-lun; Wu, Min-juan; Zhao, Ting-bao; Li, Dan-dan

2012-01-01

34

Imaging of testicular germ cell tumours  

PubMed Central

In testicular germ cell tumour (GCT), imaging plays a central role in assessment of tumour bulk, sites of metastases, monitoring response to therapy, surgical planning and accurate assessment of disease at relapse. The primary modality used for imaging patients with GCT is computed tomography (CT) but plain film radiography, ultrasound, magnetic resonance imaging (MRI) and positron emission tomography (PET) may all have roles to play. This article reviews the role of imaging of testicular germ cell tumours. PMID:16966068

Dalal, P U; Sohaib, S A; Huddart, R

2006-01-01

35

Physiological differences between neurons in layer 2 and layer 3 of primary visual cortex (V1) of alert macaque monkeys  

PubMed Central

The physiological literature does not distinguish between the superficial layers 2 and 3 of the primary visual cortex even though these two layers differ in their cytoarchitecture and anatomical connections. To distinguish layer 2 from layer 3, we have analysed the response characteristics of neurons recorded during microelectrode penetrations perpendicular to the cortical surface. Extracellular responses of single neurons to sweeping bars were recorded while macaque monkeys performed a fixation task. Data were analysed from penetrations where cells could be localized to specific depths in the cortex. Although the most superficial cells (depth, 145–371 ?m; presumably layer 2) responded preferentially to particular stimulus orientations, they were less selective than cells encountered immediately beneath them (depth, 386–696 ?m; presumably layer 3). Layer 2 cells had smaller spikes, higher levels of ongoing activity, larger receptive field activating regions, and less finely tuned selectivity for stimulus orientation and length than layer 3 cells. Direction selectivity was found only in layer 3. These data suggest that layer 3 is involved in generating and transmitting precise, localized information about image features, while the lesser selectivity of layer 2 cells may participate in top-down influences from higher cortical areas, as well as modulatory influences from subcortical brain regions. PMID:18325976

Gur, Moshe; Snodderly, D Max

2008-01-01

36

Testicular Germ Cell Cancer  

Cancer.gov

More than 90 percent of testicular cancer start in the germ cells, which are cells in the testicles and develop into sperm. This type of cancer is known as testicular germ cell cancer. Testicular germ cell cancer can be classified as either seminomas or nonseminomas, whose cells have different appearances under a microscope.1 Another difference is that nonseminomas typically grow and spread more quickly than seminomas.

37

POMB\\/ACE chemotherapy for mediastinal germ cell tumours  

Microsoft Academic Search

Mediastinal germ cell tumours (MGCT) are rare and most published series reflect the experiences of individual institutions over many years. Since 1979, we have treated 16 men (12 non-seminomatous germ cell tumours and 4 seminomas) with newly diagnosed primary MGCT with POMB\\/ACE chemotherapy and elective surgical resection of residual masses. This approach yielded complete remissions in 1516 (94%) patients. The

M. Bower; C. Brock; L. Holden; A. Nelstrop; A. R. Makey; G. J. S. Rustin; E. S. Newlands

1997-01-01

38

Pyramidal Neuron Number in Layer 3 of Primary Auditory Cortex of Subjects with Schizophrenia  

PubMed Central

Individuals with schizophrenia demonstrate impairments of sensory processing within primary auditory cortex. We have previously identified lower densities of dendritic spines and axon boutons, and smaller mean pyramidal neuron somal volume, in layer 3 of the primary auditory cortex in subjects with schizophrenia, all of which might reflect fewer layer 3 pyramidal neurons in schizophrenia. To examine this hypothesis, we developed a robust stereological method based upon unbiased principles for estimation of total volume and pyramidal neuron numbers for each layer of a cortical area. Our method generates both a systematic, uniformly random set of mapping sections as well as a set of randomly rotated sections cut orthogonal to the pial surface, within the region of interest. We applied our approach in twelve subjects with schizophrenia, each matched to a normal comparison subject. Primary auditory cortex volume was assessed using Cavalieri’s method. The relative and absolute volume of each cortical layer and, within layer 3, the number and density of pyramidal neurons was estimated using our novel approach. Subject groups did not differ in regional volume, layer volumes, or pyramidal neuron number, although pyramidal neuron density was significantly greater in subjects with schizophrenia. These findings suggest that previously observed lower densities of dendritic spines and axon boutons reflect fewer numbers per neuron, and contribute to greater neuronal density via a reduced neuropil. Our approach represents a powerful new method for stereologic estimation of features of interest within individual layers of cerebral cortex, with applications beyond the current study. PMID:19524554

Dorph-Petersen, Karl-Anton; Delevich, Kristen M.; Marcsisin, Michael J.; Zhang, Wei; Sampson, Allan R.; Gundersen, Hans Jørgen G.; Lewis, David A.; Sweet, Robert A.

2009-01-01

39

Familial germ cell tumor  

PubMed Central

Familial testicular germ cell tumors are well known in literature. Only few cases are reported where both brother and sister of the same family suffered from germ cell malignancies. We present a family where the proband is a survivor of ovarian dysgerminoma stage IA. Her elder male sibling became acutely ill and was detected to have disseminated testicular malignancy with grossly elevated markers and vegetations in the mitral valve leaflets. Despite all measures he could not be saved. Presence of germ cell malignancies in the siblings of different sex in the same family points toward a genetic susceptibility. Literature review revealed only six similar cases. A discussion regarding the rare occurrence of familial germ cell malignancies with the affected family members may be worthwhile. PMID:22754236

Cyriac, Sanju; Rajendranath, Rejeev; Louis, A Robert; Sagar, T. G.

2012-01-01

40

What Are Germs?  

MedlinePLUS

... four major types of germs are: bacteria, viruses, fungi, and protozoa. They can invade plants, animals, and ... countertop, be sure to wash your hands regularly! Fungi (say: FUN-guy) are multi-celled (made of ...

41

Molecular Markers of Neuronal Subpopulations in Layers 4, 5, and 6 of Cat Primary Visual Cortex  

Microsoft Academic Search

Cat primary visual cortex has been used as an immunogen to produce monoclonal antibodies that detect subpopula- tions of neurons. When tested by immunofluorescence on tissue sections of areas 17 and 18, 2 of these antibodies, VC 1.1 and VC5.1, outlined a rare subpopulation of neurons located mainly in layer 4 but also in layers 5 and 6. Double- labeling

Y. Arimatsu; J. R. Naegele; C. J. Barnstable

1987-01-01

42

Environmentally Induced Transgenerational Epigenetic Reprogramming of Primordial Germ Cells and the Subsequent Germ Line  

PubMed Central

A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germ line are those associated with primordial germ cell development and subsequent fetal germline development. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation germline transcriptome and epigenome (DNA methylation) were altered transgenerationally. Interestingly, disruptions in DNA methylation patterns and altered transcriptomes were distinct between germ cells at the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DNA methylation abnormalities (epimutations) and transcriptional alterations were observed in the E13 germ cells than in the E16 germ cells. These observations indicate that altered transgenerational epigenetic reprogramming and function of the male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. PMID:23869203

Skinner, Michael K.; Haque, Carlos Guerrero-Bosagna M.; Nilsson, Eric; Bhandari, Ramji; McCarrey, John R.

2013-01-01

43

Environmentally induced transgenerational epigenetic reprogramming of primordial germ cells and the subsequent germ line.  

PubMed

A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germ line are those associated with primordial germ cell development and subsequent fetal germline development. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation germline transcriptome and epigenome (DNA methylation) were altered transgenerationally. Interestingly, disruptions in DNA methylation patterns and altered transcriptomes were distinct between germ cells at the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DNA methylation abnormalities (epimutations) and transcriptional alterations were observed in the E13 germ cells than in the E16 germ cells. These observations indicate that altered transgenerational epigenetic reprogramming and function of the male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. PMID:23869203

Skinner, Michael K; Guerrero-Bosagna, Carlos; Haque, M; Nilsson, Eric; Bhandari, Ramji; McCarrey, John R

2013-01-01

44

15 INTRACRANIAL GERM CELL TUMORS  

Microsoft Academic Search

Intracranial germ cell tumors are a heterogeneous group of lesions which occur in children and adults. Within the classification of intracranial germ cell tumors, there are a variety of different tumor types which carry different prognoses. The diagnosis of an intracranial germ cell tumor usually requires histological informa- tion, but a subgroup of tumors will secrete specific tumor markers, including

J Bjornsson; B Scheithauer; H Okazakl; R W Leech

1984-01-01

45

Using a silicone-based dressing as a primary wound contact layer.  

PubMed

The use of silicone-based dressings as a primary contact layer for wound care can prevent epithelial stripping, pain and sensitivity and have been widely available for nearly 20 years. Cuticell Contact from BSN medical is the latest silicone-based dressing to add to the armoury of the wound care clinician. Using documented case studies the author explores the reasoning behind why clinicians should consider re-examining the use of silicone dressings. PMID:25382127

Derbyshire, Adam

2014-11-01

46

Wheat Germ DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from wheat germ using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Lana Hays

2009-01-01

47

PGL-1, a Predicted RNA-Binding Component of Germ Granules, Is Essential for Fertility in C. elegans  

Microsoft Academic Search

Germ cells are distinct from somatic cells in their immortality, totipotency, and ability to undergo meiosis. Candidates for components that guide the unique germline program are the distinctive granules observed in germ cells of many species. We show that a component of germ granules is essential for fertility in C. elegans and that its primary function is in germline proliferation.

Ichiro Kawasaki; Yhong-Hee Shim; Jay Kirchner; Joshua Kaminker; William B. Wood; Susan Strome

1998-01-01

48

Callosal connections of the ferret primary auditory cortex  

Microsoft Academic Search

The callosal connections of ferret auditory cortex were studied by making multiple injections of wheat germ agglutinin-horseradish\\u000a peroxidase into the middle ectosylvian gyrus or by packing crystals of horseradish peroxidase into the transected corpus callosum.\\u000a The primary area (AI) had strong callosal connections that arose from somata mainly located in layer III. Other layers contained\\u000a sparsely distributed cells that projected

M. N. Wallace; Morag S. Harper

1997-01-01

49

Target-specific properties of thalamocortical synapses onto layer 4 of mouse primary visual cortex.  

PubMed

In primary sensory cortices, thalamocortical (TC) inputs can directly activate excitatory and inhibitory neurons. In vivo experiments in the main input layer (L4) of primary visual cortex (V1) have shown that excitatory and inhibitory neurons have different tuning properties. The different functional properties may arise from distinct intrinsic properties of L4 neurons, but could also depend on cell type-specific properties of the synaptic inputs from the lateral geniculate nucleus of the thalamus (LGN) onto L4 neurons. While anatomical studies identified LGN inputs onto both excitatory and inhibitory neurons in V1, their synaptic properties have not been investigated. Here we used an optogenetic approach to selectively activate LGN terminal fields in acute coronal slices containing V1, and recorded monosynaptic currents from excitatory and inhibitory neurons in L4. LGN afferents made monosynaptic connections with pyramidal (Pyr) and fast-spiking (FS) neurons. TC EPSCs on FS neurons were larger and showed steeper short-term depression in response to repetitive stimulation than those on Pyr neurons. LGN inputs onto Pyr and FS neurons also differed in postsynaptic receptor composition and organization of presynaptic release sites. Together, our results demonstrate that LGN input onto L4 neurons in mouse V1 have target-specific presynaptic and postsynaptic properties. Distinct mechanisms of activation of feedforward excitatory and inhibitory neurons in the main input layer of V1 are likely to endow neurons with different response properties to incoming visual stimuli. PMID:25392512

Kloc, Michelle; Maffei, Arianna

2014-11-12

50

Germ Cell Intercellular Bridges  

PubMed Central

Stable intercellular bridges are a conserved feature of gametogenesis in multicellular animals observed more than 100 years ago, but their function was unknown. Many of the components necessary for this structure have been identified through the study of cytokinesis in Drosophila; however, mammalian intercellular bridges have distinct properties from those of insects. Mammalian germ cell intercellular bridges are composed of general cytokinesis components with additional germ cell–specific factors including TEX14. TEX14 is an inactive kinase essential for the maintenance of stable intercellular bridges in gametes of both sexes but whose loss specifically impairs male meiosis. TEX14 acts to impede the terminal steps of abscission by competing for essential component CEP55, blocking its interaction in nongerm cells with ALIX and TSG101. Additionally, TEX14-interacting protein RBM44, whose localization in stabile intercellular bridges is limited to pachytene and secondary spermatocytes, may participate in processes such as RNA transport but is nonessential to the maintenance of intercellular bridge stability. PMID:21669984

Greenbaum, Michael P.; Iwamori, Tokuko; Buchold, Gregory M.; Matzuk, Martin M.

2011-01-01

51

Primordial Germ Cells in Mice  

PubMed Central

Germ cell development creates totipotency through genetic as well as epigenetic regulation of the genome function. Primordial germ cells (PGCs) are the first germ cell population established during development and are immediate precursors for both the oocytes and spermatogonia. We here summarize recent findings regarding the mechanism of PGC development in mice. We focus on the transcriptional and signaling mechanism for PGC specification, potential pluripotency, and epigenetic reprogramming in PGCs and strategies for the reconstitution of germ cell development using pluripotent stem cells in culture. Continued studies on germ cell development may lead to the generation of totipotency in vitro, which should have a profound influence on biological science as well as on medicine. PMID:23125014

Saitou, Mitinori; Yamaji, Masashi

2012-01-01

52

Rapid adult experience-dependent anatomical plasticity in layer IV of primary somatosensory cortex.  

PubMed

Sensory deprivation, such as whisker deprivation, is one of the most common paradigms used to examine experience-dependent plasticity. Many of these studies conducted during development have demonstrated anatomical and synaptic neocortical plasticity with varying lengths of deprivation (for review, see Holtmaat and Svoboda, 2009). However, to date, there have been few studies exploring brief periods of experience-dependent neocortical plasticity in adulthood, similar to that observed from learning and memory paradigms (Siucinska and Kossut, 1996, 2004; Galvez et al., 2006; Chau et al., 2013). Examining both synapsin I and Golgi-Cox stained neurons in primary somatosensory cortex of unilaterally whisker-deprived adult mice, the current study demonstrates that 5 days of whisker deprivation results in more synapses in spared barrels and reduced synapses in deprived barrels. To our knowledge, this is the first study to characterize anatomical changes in layer IV of primary somatosensory cortex after a brief period of sensory deprivation in adulthood. Furthermore, findings from the present study suggest that analyses from prolonged periods of either sensory deprivation or stimulation during adulthood are missing forms of plasticity that could provide better insight into various cognitive processes, such as learning and memory. PMID:24183785

Chau, Lily S; Akhtar, Omar; Mohan, Vijay; Kondilis, Athanasios; Galvez, Roberto

2014-01-16

53

Layer specific sharpening of frequency tuning by selective attention in primary auditory cortex.  

PubMed

Recent electrophysiological and neuroimaging studies provide converging evidence that attending to sounds increases the response selectivity of neuronal ensembles even at the first cortical stage of auditory stimulus processing in primary auditory cortex (A1). This is achieved by enhancement of responses in the regions that process attended frequency content, and by suppression of responses in the surrounding regions. The goals of our study were to define the extent to which A1 neuronal ensembles are involved in this process, determine its effect on the frequency tuning of A1 neuronal ensembles, and examine the involvement of the different cortical layers. To accomplish these, we analyzed laminar profiles of synaptic activity and action potentials recorded in A1 of macaques performing a rhythmic intermodal selective attention task. We found that the frequency tuning of neuronal ensembles was sharpened due to both increased gain at the preferentially processed or best frequency and increased response suppression at all other frequencies when auditory stimuli were attended. Our results suggest that these effects are due to a frequency-specific counterphase entrainment of ongoing delta oscillations, which predictively orchestrates opposite sign excitability changes across all of A1. This results in a net suppressive effect due to the large proportion of neuronal ensembles that do not specifically process the attended frequency content. Furthermore, analysis of laminar activation profiles revealed that although attention-related suppressive effects predominate the responses of supragranular neuronal ensembles, response enhancement is dominant in the granular and infragranular layers, providing evidence for layer-specific cortical operations in attentive stimulus processing. PMID:25471586

O'Connell, Monica Noelle; Barczak, Annamaria; Schroeder, Charles E; Lakatos, Peter

2014-12-01

54

Analytic surface germs with minimal Pythagoras number  

Microsoft Academic Search

We determine all complete intersection surface germs whose Pythagoras number is 2, and find that they are all embedded in R3 and have the property that every positive semidefinite analytic function germ is a sum of squares of analytic function germs. In addition, we discuss completely these properties for mixed surface germs in R3. Finally, we find in higher embedding

José F. Fernando; F. Ciencias Matematicas

2003-01-01

55

Extragonadal Germ Cell Cancer (EGC)  

MedlinePLUS

... germ cells are first seen outside of the embryo in the yolk sac. At about 4 to ... weeks of development, these cells migrate into the embryo where they populate the developing testes or ovaries. ...

56

Palifosfamide in Treating Patients With Recurrent Germ Cell Tumors  

ClinicalTrials.gov

Adult Central Nervous System Germ Cell Tumor; Adult Teratoma; Malignant Extragonadal Germ Cell Tumor; Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Extragonadal Seminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2014-07-16

57

Palifosfamide in Treating Patients With Recurrent Germ Cell Tumors  

ClinicalTrials.gov

Adult Central Nervous System Germ Cell Tumor; Adult Teratoma; Malignant Extragonadal Germ Cell Tumor; Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Extragonadal Seminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2015-01-30

58

Security risk assessment of the primary layer of wavelength division multiplexing passive optical network  

NASA Astrophysics Data System (ADS)

Next-generation passive optical access networks come to the fore nowadays. These optical next-generation networks are the response to the increasing qualitative requirements from end users. Technologies using Time Division Multiplexing include NG-PON (XG-PON 1 and XG-PON 2) and 10GEPON. Their advantage is the applicability to older topologies, which are operated by the original technology of passive optical access networks. Wavelength Division Multiplexing Passive Optical Network (WDM-PON) is an alternative also belonging to next-generation networks. Time Division Multiplexing is in this case replaced by Wavelength Division Multiplexing. Certain variants of WDM-PON use a combination of broadband light source, optical circulator, optical phased array and tunable FP laser. Construction of the terminal units (ONU) is advantageous because it can always tune in to the appropriate wavelength in the given optical DWDM channel (100 GHz). The disadvantage is the increased security risk on the primary layer due to channel crosstalk in an optical phased array (AWG). The aim of this paper is to assess the degree of security risk in real conditions. The article includes both simulation and real measurements in C + L bands with 100 GHz DWDM spacing.

Koudelka, Petr; Siska, Petr; Latal, Jan; Poboril, Radek; Hajek, Lukas; Kepak, Stanislav; Vasinek, Vladimir

2015-01-01

59

Analysis of second-harmonic generation by primary horizontal shear modes in layered planar structures with imperfect interfaces  

NASA Astrophysics Data System (ADS)

This paper describes modeling of second-harmonic generation by the primary horizontal shear (SH) mode propagation in layered planar structures with imperfect interfaces. Due to the elastic nonlinearity of the solid, there are second-order bulk driving forces in each solid layer and a second-order stress tensor at each surface/interface, accompanying the primary SH mode propagation. Within second-order perturbation, these bulk driving forces and stress tensors can be thought of as the excitation source of a series of double frequency Lamb modes (DFLMs) in terms of the approach of modal expansion analysis for waveguide excitation. The equation governing the expansion coefficient of each DFLM is developed. It is found that the expansion coefficient of each DFLM is directly coupled with the interfacial properties, characterized by the finite normal and tangential interfacial stiffnesses. Especially, the phase velocity mismatching between the primary SH mode and the DFLM, caused by the degradation of interface (with respect to the case of the perfect interface), can remarkably influence the efficiency of second-harmonic generation by the primary SH mode propagation. The potential is discussed of using the effect of second-harmonic generation by the primary SH mode propagation to evaluate the interfacial properties of layered structures.

Deng, Mingxi; Xiang, Yanxun

2013-01-01

60

Stage-dependent DAZL localization in stallion germ cells.  

PubMed

Deleted in azoospermia-like (DAZL) is used as a germ cell marker in several species, including mice, rats, pigs, rhesus monkeys, bulls, and humans. Our objectives with this study were to investigate DAZL expression in stallion germ cells by using immunofluorescence, immunocytochemistry, and western blotting, and to determine the effects of reproductive stage and breeding season on the DAZL-positive cell population in seminiferous tubule cross sections. Testes were obtained during routine castration procedures at a large animal clinic and routine field service castration. The reproductive stage of the stallions was classified as pre-pubertal (<1 yr), pubertal (1-1.5 yr), post-pubertal (2-3 yr), or adult (4-8 yr). Using immunofluorescent staining, we showed that DAZL is localized to the cytoplasm of some, but not all, spermatogonia in pre-pubertal and pubertal horses. In the post-pubertal and adult testes, DAZL immunostaining was observed in spermatogonia proximal to the basement membrane of seminiferous tubules; however, few spermatogonia attached to the basement membrane were not immunolabeled. DAZL immunostaining was also observed in primary spermatocytes, but not in secondary spermatocytes, spermatids, or spermatozoa. DAZL protein was not detected in Leydig, Sertoli, or myoid cells of the testes at any reproductive stage. The immunocytochemistry analysis showed that DAZL immunolabeling was also localized to the cytoplasm of isolated germ cells such as spermatogonia or primary spermatocytes. We conclude that DAZL can be used as a marker of pre-meiotic germ cells in stallions. PMID:24746554

Jung, H J; Song, H; Yoon, M J

2014-06-10

61

Dazl regulates mouse embryonic germ cell development  

E-print Network

In the mouse, germ cells can undergo differentiation to become either oocytes or spermatozoa in response to sex of their gonadal environment. The nature of the germ cell-intrinsic aspects of this signaling have not been ...

Gill, Mark E

2010-01-01

62

Testicular germ cell tumours: predisposition genes and the male germ cell niche  

Microsoft Academic Search

Testicular germ cell tumours (TGCTs) of adults and adolescents are putatively derived from primordial germ cells or gonocytes. Recently reported genome-wide association studies implicate six gene loci that predispose to TGCT development. Remarkably, the functions of proteins encoded by genes within these regions bridge our understanding between the pathways involved in primordial germ cell physiology, male germ cell development and

Duncan Gilbert; Elizabeth Rapley; Janet Shipley

2011-01-01

63

iBioSeminar: Germ Cell Development  

NSDL National Science Digital Library

When an egg is fertilized, two distinct groups of cells are formed; the somatic cells which give rise to all the structures in body and will ultimately die, and the primordial germ cells which become germ line stem cells that produce sperm and egg and thus, can give rise to another generation. Hence, germ cells are responsible for the maintenance of a species.

Ruth Lehmann (New York University School of Medicine; )

2009-07-01

64

PKA, Germ Cells, and Fertility  

NSDL National Science Digital Library

Temporal and spatial regulation of PKA activity are essential for vigorous sperm motility and for the resumption of meiosis in oocytes, two events required for successful fertilization. Genetic mutations in mice that affect PKA signaling in germ cells lead to infertility and illustrate the importance of this pathway in mammalian reproduction.

2007-02-01

65

HISTORY OF GERM CELL MUTAGENESIS  

EPA Science Inventory

Much of the early work on germ cell mutation analysis was conducted with nonmammalian species, but this historical overview will begin with the rodent studies that provided quantitative data on induced mutations. The initial studies of mutation induction utilized the newly develo...

66

Matrix metalloproteinase expression in primary lung fibroblasts of layer type chickens.  

PubMed

We attempted to determine the growth characteristics of cultured lung fibroblasts of layer type chickens and to investigate presence of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in these cells in vitro. Lung fibroblasts were isolated, characterized and subcultured from one-day-old layer type chicken lungs. Two different methods, explant culture and enzymatic techniques, were used for culturing and the results were compared. The presence of MMP-2 and TIMP-1 was shown in cultured fibroblasts by immunocytochemical staining, immune blotting and zymography methods. Immune expressions of neither MMP-9 nor TIMP-2 enzymes could be detected. PMID:21916781

Akkoc, A; Kahraman, M M

2012-04-01

67

Familial Testicular Germ Cell Tumors  

PubMed Central

In this review, we define familial testicular germ cell tumors (FTGCT) as testicular germ cell tumors (TGCT) diagnosed in at least two blood relatives, a situation which occurs in 1-2% of all cases of TGCT. Brothers and fathers of TGCT patients have an 8-10 and 4-6 fold increased risk of TGCT, respectively, and an even higher elevated risk of TGCT in twin brothers of men with TGCT has been observed, suggesting that genetic elements play an important role in these tumors. Nevertheless, previous linkage studies with multiple FTGCT families did not uncover any high-penetrance genes and it has been concluded that the combined effects of multiple common alleles, each conferring modest risk, might underlie FTGCT. In agreement with this assumption, recent candidate gene association analyses have identified the chromosome Y gr/gr deletion and mutations in the PDE11A gene as genetic modifiers of FTGCT risk. Moreover, two genomewide association studies of predominantly sporadic but also familial cases of TGCT have identified three additional susceptibility loci, KITLG, SPRY4 and BAK1. Notably, all five loci are involved in the biology of primordial germ cells, representing the cell of origin of TGCT, suggesting that the tumors arise as a result of disturbed testicular development. PMID:20833340

Kratz, Christian P.; Mai, Phuong L.; Greene, Mark H.

2010-01-01

68

Layer- and cell-type-specific suprathreshold stimulus representation in rat primary somatosensory cortex  

PubMed Central

Sensory stimuli are encoded differently across cortical layers and it is unknown how response characteristics relate to the morphological identity of responding cells. We therefore juxtasomally recorded action potential (AP) patterns from excitatory cells in layer (L) 2/3, L4, L5 and L6 of rat barrel cortex in response to a standard stimulus (e.g. repeated deflection of single whiskers in the caudal direction). Subsequent single-cell filling with biocytin allowed for post hoc identification of recorded cells. We report three major conclusions. First, sensory-evoked responses were layer- and cell-type-specific but always < 1 AP per stimulus, indicating low AP rates for the entire cortical column. Second, response latencies from L4, L5B and L6 were comparable and thus a whisker deflection is initially represented simultaneously in these layers. Finally, L5 thick-tufted cells dominated the cortical AP output following sensory stimulation, suggesting that these cells could direct sensory guided behaviours. PMID:17317752

de Kock, C P J; Bruno, R M; Spors, H; Sakmann, B

2007-01-01

69

PGL-1, a predicted RNA-binding component of germ granules, is essential for fertility in C. elegans.  

PubMed

Germ cells are distinct from somatic cells in their immortality, totipotency, and ability to undergo meiosis. Candidates for components that guide the unique germline program are the distinctive granules observed in germ cells of many species. We show that a component of germ granules is essential for fertility in C. elegans and that its primary function is in germline proliferation. This role has been revealed by molecular and genetic analyses of pgl-1. PGL-1 is a predicted RNA-binding protein that is present on germ granules at all stages of development. Elimination of PGL-1 results in defective germ granules and sterility. Interestingly, PGL-1 function is required for fertility only at elevated temperatures, suggesting that germline development is inherently sensitive to temperature. PMID:9741628

Kawasaki, I; Shim, Y H; Kirchner, J; Kaminker, J; Wood, W B; Strome, S

1998-09-01

70

Assessment of Speech in Primary Cleft Palate by Two-layer Closure (Conservative Management)  

PubMed Central

Treatment of the cleft palate has evolved over a long period of time. Various techniques of cleft palate repair that are practiced today are the results of principles learned through many years of modifications. The challenge in the art of modern palatoplasty is no longer successful closure of the cleft palate but an optimal speech outcome without compromising maxillofacial growth. Throughout these periods of evolution in the treatment of cleft palate, the effectiveness of various treatment protocols has been challenged by controversies concerning speech and maxillofacial growth. In this article we have evaluated the results of Pinto's modification of Wardill–Kilner palatoplasty without radical dissection of the levator veli palitini muscle on speech and post-op fistula in two different age groups in 20 patients. Preoperative and 6-month postoperative speech assessment values indicated that two-layer palatoplasty (modified Wardill–Kilner V-Y pushback technique) without an intravelar veloplasty technique was good for speech. PMID:23066454

Jain, Harsha; Rao, Dayashankara; Sharma, Shailender; Gupta, Saurabh

2012-01-01

71

The use of an antimicrobial primary wound contact layer as liner and filler with NPWT.  

PubMed

In negative pressure wound therapy (NPWT), wound fillers are used to ensure that the negative pressure is applied across the entire wound surface. At present, foam and gauze are the most commonly used fillers. Both ensure equal distribution of negative pressure, but foam is more absorbent, while gauze is more malleable and conformable. There is no strong clinical research evidence demonstrating the superiority of one type of wound filler over another. However, there are reports that foam can cause pain and trauma at dressing change as a result of ingrowth of tissue into its open pore structure. For this reason, when foam is used as a filler, a liner may also be applied as a wound contact layer. This supplement describes preliminary clinical evidence on the use of Cutimed Sorbact as an alternative to foam and gauze during NPWT. Seven cases in which it was successfully used on complex pre- and postoperative wounds are described PMID:25507332

Jeffery, Steven L A

2014-08-01

72

The use of an antimicrobial primary wound contact layer as liner and filler with NPWT.  

PubMed

In negative pressure wound therapy (NPWT), wound fillers are used to ensure that the negative pressure is applied across the entire wound surface. At present, foam and gauze are the most commonly used fillers. Both ensure equal distribution of negative pressure, but foam is more absorbent, while gauze is more malleable and conformable. There is no strong clinical research evidence demonstrating the superiority of one type of wound filler over another. However, there are reports that foam can cause pain and trauma at dressing change as a result of ingrowth of tissue into its open pore structure. For this reason, when foam is used as a filler, a liner may also be applied as a wound contact layer. This supplement describes preliminary clinical evidence on the use of Cutimed Sorbact as an alternative to foam and gauze during NPWT. Seven cases in which it was successfully used on complex pre- and postoperative wounds are described PMID:25420348

Jeffery, Steven L A

2014-08-01

73

[The nutritive value of wheat germ floc].  

PubMed

The experimental investigation of the food value of wheat germ floc included the study of their chemical composition, biological value, and assimilability of the protein. Basing on the results obtained the authors have made a conclusion on the high food value of wheat germ floc and on their promising use as enriching additives to varying foodstuffs. PMID:2399684

Safronova, A M; Vysotski?, V G; Narodetskaia, R V; Trushina, E N; Sandakova, G K; Kolkunova, G K

1990-01-01

74

The value of resequence data for poultry breeding: a primary layer breeder perspective.  

PubMed

Poultry breeding companies are facing a new paradigm. Since 2004, extensive resources have been developed to increase understanding of the fundamental biology of the chicken. The chicken genome has been sequenced and revised twice, millions of novel DNA variants have been identified, and new tools have been created that allow rapid and inexpensive detection of these DNA variations. These developments have led to the establishment of molecular-based breeding programs within major poultry breeding companies that are revolutionizing the primary poultry breeding industries. Costs of sequencing continue to drop and are predicted to eventually reach the point where it is feasible to sequence the entire genome of elite birds before selection. There are multiple challenges to be resolved before this information can be fully incorporated into a breeding program. These include handling and analyzing the extremely large data sets generated, understanding which genes, variants, or both are relevant for commercial production traits, development of new bio-informatic tools, and integration of molecular information with traditional breeding programs. The novel variation identified within elite commercial lines will lead to enhancements in commercial breeding programs. Applications of this information include whole genomic selection, parentage identification, trait association studies, and quality control. PMID:24570474

Fulton, Janet E

2014-02-01

75

Stochastic specification of primordial germ cells from mesoderm precursors in axolotl embryos.  

PubMed

A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these disparate mechanisms of PGC specification evolved is unknown. Here, in order to identify the ancestral mechanism of PGC specification in vertebrates, we studied PGC specification in embryos from the axolotl (Mexican salamander), a model for the tetrapod ancestor. In the axolotl, PGCs develop within mesoderm, and classic studies have reported their induction from primitive ectoderm (animal cap). We used an axolotl animal cap system to demonstrate that signalling through FGF and BMP4 induces PGCs. The role of FGF was then confirmed in vivo. We also showed PGC induction by Brachyury, in the presence of BMP4. These conditions induced pluripotent mesodermal precursors that give rise to a variety of somatic cell types, in addition to PGCs. Irreversible restriction of the germ line did not occur until the mid-tailbud stage, days after the somatic germ layers are established. Before this, germline potential was maintained by MAP kinase signalling. We propose that this stochastic mechanism of PGC specification, from mesodermal precursors, is conserved in vertebrates. PMID:24917499

Chatfield, Jodie; O'Reilly, Marie-Anne; Bachvarova, Rosemary F; Ferjentsik, Zoltan; Redwood, Catherine; Walmsley, Maggie; Patient, Roger; Loose, Mathew; Johnson, Andrew D

2014-06-01

76

Primary hydatid cyst of the supraspinatus muscle: complete removal of the germinal layer and cytodiagnosis by fine-needle aspiration.  

PubMed

Primary hydatid disease of the skeletal muscle without systemic involvement is rare. The purpose of this report is to document the novel clinical presentation and the interesting facets of fine-needle aspiration in a case of hydatid disease. It was a case of primary hydatid cyst of the left supraspinatus muscle in an Indian woman living in Kuwait, which was clinically diagnosed as a lipoma. Fine-needle aspiration (FNA) yielded 2 ml of clear fluid with white particulate material. The cytocentrifuged smears prepared from the aspirated fluid showed many scolices, occasional laminated cyst wall fragments and numerous hooklets. The laminated cyst wall and scolices were PAS positive. Trichrome staining imparted a demon-head-like appearance to the scolices. The cytodiagnosis of hydatid cyst was corroborated by histopathological examination of an excised whitish membrane and an irregular cystic fragment, which showed parallel laminations without germinal layer, and skeletal muscle with granulomas and a dense eosinophilic infiltration, respectively. Quantitative serological (indirect hemagglutination) test on blood sample collected 9 days after the excision of the cyst showed insignificant antibody titer to Echinococcus sp. and after 6 weeks the antibodies were completely absent. CT scan of the chest and abdomen performed 7 weeks after removal of cyst showed no evidence of visceral hydatid cyst. PMID:23008130

Das, Dilip K; El-Sharawy, Maha; Ayyash, Emad H; Al-Enezi, Nadia A; Iqbal, Jamshed R; Madda, John P

2014-03-01

77

POMB/ACE chemotherapy for mediastinal germ cell tumours.  

PubMed

Mediastinal germ cell tumours (MGCT) are rare and most published series reflect the experiences of individual institutions over many years. Since 1979, we have treated 16 men (12 non-seminomatous germ cell tumours and 4 seminomas) with newly diagnosed primary MGCT with POMB/ACE chemotherapy and elective surgical resection of residual masses. This approach yielded complete remissions in 15/16 (94%) patients. The median follow-up was 6.0 years and no relapses occurred more than 2 years after treatment. The 5 year overall survival in the non-seminomatous germ cell tumours (NSGCT) is 73% (95% confidence interval 43-90%). One patient with NSGCT developed drug-resistant disease and died without achieving remission and 2 patients died of relapsed disease. In addition, 4 patients with bulky and/or metastatic seminoma were treated with POMB/ACE. One died of treatment-related neutropenic sepsis in complete remission and one died of relapsed disease. Finally, 4 patients (2 NSGCT and 2 seminomas) referred at relapse were treated with POMB/ACE and one was successfully salvaged. The combination of POMB/ACE chemotherapy and surgery is effective management for MGCT producing high long-term survival rates. PMID:9291802

Bower, M; Brock, C; Holden, L; Nelstrop, A; Makey, A R; Rustin, G J; Newlands, E S

1997-05-01

78

Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow  

NASA Astrophysics Data System (ADS)

This paper is devoted to the investigation of three primary linear instability mechanisms due to the resonating disturbance waves present in the three-dimensional incompressible viscous/inviscid rotating disk boundary layer flow, extending our earlier still outer fluid work [M. Turkyilmazoglu, "Resonance instabilities on the boundary layer flow over a rotating-disk under the influence of a uniform magnetic field," J. Eng. Math. 59, 337 (2007)] to a uniform nonzero radial flow. A spatiotemporal linear stability analysis is conducted to search for the influences of physical parameters on the possible important mechanisms of resonances leading to, respectively, the absolute instability, the direct spatial instability, and the direct temporal instability. The radial flow is shown to act in the way of stabilizing all the possible mechanisms considered, more pronouncedly as the magnetic field gets strengthened. The onset of absolute instability and convective temporal instability is found to be more sensitive to the variations in the radial flow than is the onset of convective direct spatial instability. Although a considerable delay of the onset of absolute instability as well as temporal instability can be achieved by increasing the magnitude of the radial flow, the direct spatial resonance instability mechanism persists to occur for low Reynolds numbers, while the flow is still in the laminar regime, which is expected to trigger nonlinearity just prior to transition to turbulence.

Turkyilmazoglu, M.

2009-07-01

79

In vivo epigenomic profiling of germ cells reveals germ cell molecular signatures.  

PubMed

The limited number of in vivo germ cells poses an impediment to genome-wide studies. Here, we applied a small-scale chromatin immunoprecipitation sequencing (ChIP-seq) method on purified mouse fetal germ cells to generate genome-wide maps of four histone modifications (H3K4me3, H3K27me3, H3K27ac, and H2BK20ac). Comparison of active chromatin state between somatic, embryonic stem, and germ cells revealed promoters and enhancers needed for stem cell maintenance and germ cell development. We found the nuclear receptor Nr5a2 motif to be enriched at a subset of germ cell cis-regulatory regions, and our results implicate Nr5a2 in germ cell biology. Interestingly, in germ cells, the H3K27me3 histone modification occurs more frequently at regions that are enriched for retrotransposons and MHC genes, indicating that these loci are specifically silenced in germ cells. Together, our study provides genome-wide histone modification maps of in vivo germ cells and reveals the molecular chromatin signatures of germ cells. PMID:23352811

Ng, Jia-Hui; Kumar, Vibhor; Muratani, Masafumi; Kraus, Petra; Yeo, Jia-Chi; Yaw, Lai-Ping; Xue, Kun; Lufkin, Thomas; Prabhakar, Shyam; Ng, Huck-Hui

2013-02-11

80

Characterisation of the oxide layer on carbon steel during hot conditioning of primary heat transport systems in heavy-water reactors  

Microsoft Academic Search

The corrosion layer formation on carbon steel during hot conditioning of primary heat transport systems of pressurised heavy-water reactors has been characterised using ex-situ methods (gravimetry, electron microscopy, X-ray diffractometry). In addition, the electric and electrochemical properties of the corrosion layers have been followed in-situ by voltammetry and electrochemical impedance spectroscopy during exposure to simulated hot conditioning water chemistry. The

Martin Bojinov; Krishna Gaonkar; Swati Ghosh; Vivekanand Kain; Kiran Kumar; Timo Saario

2009-01-01

81

Germ-cell origin in the adult caecilian Ichthyophis glutinosus (Linn)  

Microsoft Academic Search

In Ichthyophis glutinosus, no residual spermatogonia traceable to primordial germ cells of the embryo are seen, the primary spermatogonia of each season being formed afresh. Their only source so far as the adult is concerned, is the lining of the collecting duct and its numerous branches which ramify in the testis. No evidences of their origin from the surface epithelial

B. R. Seshachar

1937-01-01

82

Germ cell development in the descended and cryptorchid testis and the effects of hormonal manipulation  

Microsoft Academic Search

Germ cell development is an active process in normal testes during the first 4 years after birth, with transformation of the neonatal gonocytes into adult dark spermatogonia and then primary spermatocytes. The hormonal regulation of these changes is not fully understood, with evidence both for and against a role for gonadotrophins and androgens. Early surgical intervention in infancy aims to prevent

C. Ong; S. Hasthorpe; J. M. Hutson

2005-01-01

83

Layer 4 in Primary Visual Cortex of the Awake Rabbit: Contrasting Properties of Simple Cells and Putative Feedforward Inhibitory Interneurons  

PubMed Central

Extracellular recordings were obtained from two cell classes in layer 4 of the awake rabbit primary visual cortex (V1): putative inhibitory interneurons [suspected inhibitory interneurons (SINs)] and putative excitatory cells with simple receptive fields. SINs were identified solely by their characteristic response to electrical stimulation of the lateral geniculate nucleus (LGN, 3+ spikes at >600 Hz), and simple cells were identified solely by receptive field structure, requiring spatially separate ON and/or OFF subfields. Notably, no cells met both criteria, and we studied 62 simple cells and 33 SINs. Fourteen cells met neither criterion. These layer 4 populations were markedly distinct. Thus, SINs were far less linear (F1/F0 < 1), more broadly tuned to stimulus orientation, direction, spatial and temporal frequency, more sensitive to contrast, had much higher spontaneous and stimulus-driven activity, and always had spatially overlapping ON/OFF receptive subfields. SINs responded to drifting gratings with increased firing rates (F0) for all orientations and directions. However, some SINs showed a weaker modulated (F1) response sharply tuned to orientation and/or direction. SINs responded at shorter latencies than simple cells to stationary stimuli, and the responses of both populations could be sustained or transient. Transient simple cells were more sensitive to contrast than sustained simple cells and their visual responses were more frequently suppressed by high contrasts. Finally, cross-correlation between LGN and SIN spike trains confirmed a fast and precisely timed monosynaptic connectivity, supporting the notion that SINs are well suited to provide a fast feedforward inhibition onto targeted cortical populations. PMID:23843510

Zhuang, Jun; Stoelzel, Carl R.; Bereshpolova, Yulia; Huff, Joseph M.; Hei, Xiaojuan; Alonso, Jose-Manuel

2013-01-01

84

Testicular germ cell tumours: predisposition genes and the male germ cell niche.  

PubMed

Testicular germ cell tumours (TGCTs) of adults and adolescents are putatively derived from primordial germ cells or gonocytes. Recently reported genome-wide association studies implicate six gene loci that predispose to TGCT development. Remarkably, the functions of proteins encoded by genes within these regions bridge our understanding between the pathways involved in primordial germ cell physiology, male germ cell development and the molecular pathology of TGCTs. Furthermore, this improved understanding of the mechanisms underlying TGCT development and dissemination has clinical relevance for the management of patients with these tumours. PMID:21412254

Gilbert, Duncan; Rapley, Elizabeth; Shipley, Janet

2011-04-01

85

Epigenetic reprogramming in mouse primordial germ cells  

Microsoft Academic Search

Genome-wide epigenetic reprogramming in mammalian germ cells, zygote and early embryos, plays a crucial role in regulating genome functions at critical stages of development. We show here that mouse primordial germ cells (PGCs) exhibit dynamic changes in epigenetic modifications between days 10.5 and 12.5 post coitum (dpc). First, contrary to previous suggestions, we show that PGCs do indeed acquire genome-wide

Petra Hajkova; Sylvia Erhardt; Thomas Haaf; Osman El-Maarri; Wolf Reik; Jörn Walter; M. Azim Surani

2002-01-01

86

Layers  

NASA Astrophysics Data System (ADS)

The temperature-dependent photoresponse characteristics of MnAl2S4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with band-to-band transitions from the valence-band states ?4( z), ?5( x), and ?5( y) to the conduction-band state ?1( s). On the basis of the relationship between PC-peak energy and temperature, the optical band gap could be well expressed by the expression E g( T) = E g(0) - 2.80 × 10-4 T 2/(287 + T), where E g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-band states ?4( z), ?5( x), and ?5( y), respectively. Results from PC spectroscopy revealed the crystal-field and spin-orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl2S4 layers. Plots of log J ph, the PC current density, against 1/ T, revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the conduction band.

Hong, K. J.; Jeong, T. S.; Youn, C. J.

2014-09-01

87

Reduced Cortical Thickness in Primary Open-Angle Glaucoma and Its Relationship to the Retinal Nerve Fiber Layer Thickness  

PubMed Central

Objectives To examine possible changes in cortical thickness and their relationship to retinal nerve fiber layer (RNFL) thickness in patients with primary open-angle glaucoma (POAG). Materials and Methods Thirty-six patients with POAG and 40 matched healthy controls were enrolled in this study. All subjects underwent a comprehensive ophthalmologic examination and a high resolution structural magnetic resonance scan. Cortical thickness analysis was used to assess the changes between patients and controls. Correlations between the thickness of the visual cortex and RNFL thickness were also analyzed. Finally, the relationship between the severity of changes in the visual cortex and RNFL thickness was evaluated by comparing patients with mild and severe groups. Results POAG patients showed significant bilateral cortical thinning in the anterior half of the visual cortex around the calcarine sulci (left BA 17 and BA 18, right BA17) and in some smaller regions located in the left middle temporal gyrus (BA37) and fusiform gyrus (BA19). The thickness of the visual cortex correlated positively with RNFL thickness (left, r = 0.44, p = 0.01; right, r = 0.38, p = 0.03). Significant differences between mild and severe groups were observed with regard to both RNFL thickness and the thickness of bilateral visual cortex (p < 0.05). Conclusion Our findings indicate that cortical thickness analysis may be sufficiently sensitive to detect cortical alterations in POAG and that the measurement has great potential for clinical application. PMID:24019910

Yin, Xuntao; Liang, Minglong; Evans, Alan C.; Wang, Jian; Dai, Chao

2013-01-01

88

Seasonal variability of primary production and phytoplankton biomass in the western Pacific subarctic gyre: Control by light availability within the mixed layer  

NASA Astrophysics Data System (ADS)

distinct seasonal variation of primary production was revealed from shipboard observations conducted from 2005 to 2013 at time series station K2 in the western Pacific subarctic gyre (WSG). The mean depth-integrated primary production was highest (569 ± 162 mg C m-2 d-1) in summer and lowest (101 ± 16 mg C m-2 d-1) in winter. Strong winter mixing enriched the mixed layer (ML) with nutrients that were not fully consumed during the remainder of the year, the result being that the WSG was a high-nutrient, low-chlorophyll (HNLC) region. The deep ML reduced primary production by reducing light availability in winter, whereas primary production was enhanced by strong light availability in the shallower ML as summer progressed. However, primary production was often attenuated by a reduction of light availability attributable to dense sea fog in summer. We found a significant relationship between primary production and light availability in this HNLC region. However, chlorophyll a was less variable seasonally than primary production. The highest depth-integrated chlorophyll a was observed in summer (54.6 ± 13.4 mg m-2), but chlorophyll a remained high in winter (45.3 ± 7.7 mg m-2). Reduced light availability depressed primary production, but a reduction of the chlorophyll a concentration was prevented by a relaxation of grazing in the deep ML during winter. We found that light availability exerted an important control on the seasonal variability of primary production and phytoplankton biomass in the WSG.

Matsumoto, Kazuhiko; Honda, Makio C.; Sasaoka, Kosei; Wakita, Masahide; Kawakami, Hajime; Watanabe, Shuichi

2014-09-01

89

Current advances in the diagnosis and management of intracranial germ cell tumors.  

PubMed

Central nervous system (CNS) germ cell tumors (GCT) account for less than 5% of primary brain tumors in children and young adults, but they continue to attract much attention. Over the past decade, two advances have led to re-evaluation of what constitutes conventional therapy for CNS GCT. For pure germinomas, the challenge remains the determination of the optimal field and dose of irradiation and whether or not the use of chemotherapy can lead to a reduced dose or elimination of irradiation altogether without compromising disease control or survival. For non-germinomatous germ cell tumors, an improvement in the current dismal prognosis is imperative. PMID:15102352

Balmaceda, Casilda; Finlay, Jonathan

2004-05-01

90

Fatty acid composition of spermatozoa and immature germ cells.  

PubMed

A great deal of attention has recently been given to the essential role of polyunsaturated fatty acids (PUFA) of sperm membranes. We studied the fatty acid composition of the immature germ cells (IGC) and of the sperm populations separated by Percoll gradient in the ejaculate of normozoospermic patients. Fatty acid pattern was analysed by combined gas chromatography-mass spectrometry on a capillary column. In IGC, differences were found compared with mature spermatozoa, with a higher percentage of saturated fatty acids and of essential fatty acids. On the contrary, the long-chain PUFA were significantly lower in IGC. The highest concentration of n3 PUFA docohexaenoic acid (DHA) was detected in the spermatozoa deriving from 70-100% Percoll layers and a direct linear correlation was found between the increase of DHA and increased percentage of Percoll gradient. An inverse relationship between the percentage of atypical sperm forms in each layer and the percentage of DHA was also observed. This study demonstrates that the human germ cell line can elongate and desaturate essential fatty acids and that the percentage of long-chain PUFA is correlated with the normal morphology of sperm cells. PMID:10694269

Lenzi, A; Gandini, L; Maresca, V; Rago, R; Sgrò, P; Dondero, F; Picardo, M

2000-03-01

91

Germ cell tumors of the CNS in children: recent advances in therapy.  

PubMed

Primary germ cell tumors of the central nervous system are rare neoplasms, accounting for no more than 2% of all malignancies in children and young people under 20 in the Western hemisphere. They have unique features related to age at diagnosis and sites of origin, as well as race and gender predilection. Prognosis has been clearly shown to be strongly related to pathological classification as either pure germinoma or nongerminomatous germ cell tumor, although many of these lesions are comprised of mixed elements. The presence of serum or cerebrospinal fluid tumor marker elevation has been an essential determinant of response to treatment. Because of the deleterious effects of irradiation on the immature nervous system, investigators have used chemotherapeutic strategies that either reduce or eliminate radiation therapy. In this article, we review the most recent advances in therapy for CNS germ cell tumors in the pediatric population and highlight the importance of cooperative trials in this setting. PMID:10550589

Diez, B; Balmaceda, C; Matsutani, M; Weiner, H L

1999-10-01

92

"Life in a Germ-Free World":  

PubMed Central

Summary: This article examines a specific technology, the germ-free "isolator," tracing its development across three sites: (1) the laboratory for the production of standard laboratory animals, (2) agriculture for the efficient production of farm animals, and (3) the hospital for the control and prevention of cross-infection and the protection of individuals from infection. Germ-free technology traveled across the laboratory sciences, clinical and veterinary medicine, and industry, yet failed to become institutionalized outside the laboratory. That germ-free technology worked was not at issue. Working, however, was not enough. Examining the history of a technology that failed to find widespread application reveals the labor involved in aligning cultural, societal, and material factors necessary for successful medical innovation. PMID:23000838

Kirk, Robert G. W.

2012-01-01

93

Turning Points in Science: Germ Theory  

NSDL National Science Digital Library

This resource guide from the Middle School Portal 2 project, written specifically for teachers, provides links to exemplary resources including background information, lessons, career information, and related national science education standards. Germ theory represents the culmination of the work of several individuals across time. Resources provided here will facilitate understanding of the early scientific community's concept of disease; the thinking that led to hypotheses relating germs to disease; the various observations and experiments that yielded information allowing for theorizing; the scientific community's reaction to and acceptance of the early investigators' findings; and the impacts of the theory on humanity.

Mary LeFever

94

GERM as a tool for space station documentation  

NASA Technical Reports Server (NTRS)

GERM as a tool for space station documentation is presented in the form of viewgraphs. The following subject areas are covered: problem statement, hypermedia as a tool for documentation, description of GERM, technical approach, application development, and results and conclusions.

Crouse, Ken; Hardwick, Charles

1990-01-01

95

Response to ``Comment on `Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow''' [Phys. Fluids 22, 029102 (2010)  

NASA Astrophysics Data System (ADS)

It was pointed out by Thess [``Comment on `Oblique axisymmetric stagnation flows in magnetohydrodynamics [Phys. Fluids 19, 114106 (2007)]','' Phys. Fluids 20, 069102 (2008)] by Amaouche that the model used in the paper "Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow" by Turkyilmazoglu [Phys. Fluids 21, 074103 (2009)] is incomplete since the electric potential was neglected. This point is clarified here, and the ambiguity present in the magnetohydrodynamic flow research of this kind among the fluid dynamic community is remedied. As a consequence, the qualitative validity of the results in the work of Turkyilmazoglu ["Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow," Phys. Fluids 21, 074103 (2009)] from both the physical and mathematical viewpoints is justified.

Turkyilmazoglu, M.

2010-02-01

96

Galactic Cosmic Ray Event-Based Risk Model (GERM) Code  

NASA Technical Reports Server (NTRS)

This software describes the transport and energy deposition of the passage of galactic cosmic rays in astronaut tissues during space travel, or heavy ion beams in patients in cancer therapy. Space radiation risk is a probability distribution, and time-dependent biological events must be accounted for physical description of space radiation transport in tissues and cells. A stochastic model can calculate the probability density directly without unverified assumptions about shape of probability density function. The prior art of transport codes calculates the average flux and dose of particles behind spacecraft and tissue shielding. Because of the signaling times for activation and relaxation in the cell and tissue, transport code must describe temporal and microspatial density of functions to correlate DNA and oxidative damage with non-targeted effects of signals, bystander, etc. These are absolutely ignored or impossible in the prior art. The GERM code provides scientists data interpretation of experiments; modeling of beam line, shielding of target samples, and sample holders; and estimation of basic physical and biological outputs of their experiments. For mono-energetic ion beams, basic physical and biological properties are calculated for a selected ion type, such as kinetic energy, mass, charge number, absorbed dose, or fluence. Evaluated quantities are linear energy transfer (LET), range (R), absorption and fragmentation cross-sections, and the probability of nuclear interactions after 1 or 5 cm of water equivalent material. In addition, a set of biophysical properties is evaluated, such as the Poisson distribution for a specified cellular area, cell survival curves, and DNA damage yields per cell. Also, the GERM code calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle in a selected material. The GERM code makes the numerical estimates of basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the first option, properties of monoenergetic beams are treated. In the second option, the transport of beams in different materials is treated. Similar biophysical properties as in the first option are evaluated for the primary ion and its secondary particles. Additional properties related to the nuclear fragmentation of the beam are evaluated. The GERM code is a computationally efficient Monte-Carlo heavy-ion-beam model. It includes accurate models of LET, range, residual energy, and straggling, and the quantum multiple scattering fragmentation (QMSGRG) nuclear database.

Cucinotta, Francis A.; Plante, Ianik; Ponomarev, Artem L.; Kim, Myung-Hee Y.

2013-01-01

97

Comment on ``Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow'' [Phys. Fluids 21, 074103 (2009)  

NASA Astrophysics Data System (ADS)

It is pointed out that the model used in the paper "Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow" by Turkyilmazoglu [Phys. Fluids 21, 074103 (2009)] is incomplete since the electric potential has been neglected. The results of the work should therefore be considered as qualitative until the analysis has been repeated using the correct set of equations.

Thess, André

2010-02-01

98

Germ cell nuclear factor is not required for the down-regulation of pluripotency markers in fetal ovarian germ cells  

E-print Network

In mouse, germ cells retain expression of the pluripotency markers Oct4 and Nanog longer than any other cells in the body. While somatic cells repress these markers during gastrulation, female germ cells continue to express ...

Okumura, Leah M

2012-01-01

99

Ultrastructural observations on the germ line of Xenopus laevis  

Microsoft Academic Search

The development of the male germ line in Xenopus laevis has been examined by electron microscopy. Findings have been compared to the parallel process in the female. Three structures unique to the germ line were found in both male and female cells: a fibrillar nuclear region free of DNA; largely proteinaceous masses of nuage material; and a chromatoid body. “Germ

Marvin R. Kalt

1973-01-01

100

Prospects & Overviews Vasa genes: Emerging roles in the germ  

E-print Network

Prospects & Overviews Vasa genes: Emerging roles in the germ line and in multipotent cells Eric A; multipotent cells; primordial germ cell; Vasa; zinc-knuckle Introduction Segregation and maintenance in adulthood, from a multi- potent stem cell precursor (persistent multipotent cell-derived germ cells

Wessel, Gary M.

101

Exclusion of germ plasm proteins from somatic lineages by  

E-print Network

from somatic lineages by cullin-dependent degradation Cynthia DeRenzo1 *, Kimberly J. Reese1, or `germ plasm', to a small number of germline precursor cells during early embryogenesis1 . Germ plasm-germline (somatic) cells. We show that five CCCH finger proteins, components of the Cae- norhabditis elegans germ

Seydoux, Geraldine

102

Divergent RNA-binding proteins, DAZL and VASA, induce meiotic progression in human germ cells derived in vitro.  

PubMed

Our understanding of human germ cell development is limited in large part due to inaccessibility of early human development to molecular genetic analysis. Pluripotent human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been shown to differentiate to cells of all three embryonic germ layers, as well as germ cells in vitro, and thus may provide a model for the study of the genetics and epigenetics of human germline. Here, we examined whether intrinsic germ cell translational, rather than transcriptional, factors might drive germline formation and/or differentiation from human pluripotent stem cells in vitro. We observed that, with overexpression of VASA (DDX4) and/or DAZL (Deleted in Azoospermia Like), both hESCs and iPSCs differentiated to primordial germ cells, and maturation and progression through meiosis was enhanced. These results demonstrate that evolutionarily unrelated and divergent RNA-binding proteins can promote meiotic progression of human-derived germ cells in vitro. These studies describe an in vitro model for exploring specifics of human meiosis, a process that is remarkably susceptible to errors that lead to different infertility-related diseases. PMID:22162380

Medrano, Jose V; Ramathal, Cyril; Nguyen, Ha N; Simon, Carlos; Reijo Pera, Renee A

2012-03-01

103

Divergent RNA-Binding Proteins, DAZL and VASA, Induce Meiotic Progression in Human Germ Cells Derived In Vitro  

PubMed Central

Our understanding of human germ cell development is limited in large part due to inaccessibility of early human development to molecular genetic analysis. Pluripotent human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been shown to differentiate to cells of all three embryonic germ layers, as well as germ cells in vitro, and thus may provide a model for the study of the genetics and epigenetics of human germline. Here, we examined whether intrinsic germ cell translational, rather than transcriptional, factors might drive germline formation and/or differentiation from human pluripotent stem cells in vitro. We observed that, with overexpression of VASA (DDX4) and/or DAZL (Deleted in Azoospermia Like), both hESCs and iPSCs differentiated to primordial germ cells, and maturation and progression through meiosis was enhanced. These results demonstrate that evolutionarily unrelated and divergent RNA-binding proteins can promote meiotic progression of human-derived germ cells in vitro. These studies describe an in vitro model for exploring specifics of human meiosis, a process that is remarkably susceptible to errors that lead to different infertility-related diseases. PMID:22162380

Medrano, Jose v.; Ramathal, Cyril; Nguyen, Ha N.; Simon, Carlos; Pera, Renee A. Reijo

2013-01-01

104

The fused toes locus is essential for somatic-germ cell interactions that foster germ cell maturation in developing gonads in mice.  

PubMed

Ovarian development absolutely depends on communication between somatic and germ cell components. In contrast, it is not until after birth that interactions between somatic and germ cells play an important role in testicular maturation and spermatogenesis. Previously, we discovered that Irx3 expression was localized specifically to female gonads during embryonic development; therefore, we sought to determine the function of this genetic locus in developing gonads of both sexes. The fused toes (Ft) mutant mouse is missing 1.6 Mb of chromosome 8, which includes the entire IrxB cluster (Irx3, Irx5, Irx6), Ftm, Fts, and Fto genes. Homozygote Ft mutant embryos die around embryonic day 13.5 (E13.5); therefore, to assess later development, we harvested gonads at E11.5 and transplanted them into nude mouse hosts. Our results show defects in somatic and germ cell maturation in developing gonads of both sexes. Testis development was normal initially; however, by 3-wk posttransplantation, expression of Sertoli and peritubular myoid cell markers were decreased. In many cases, gonocytes failed to migrate to structurally impaired basement membranes of seminiferous cords. Developmental abnormalities of the ovary appeared earlier and were more severe. Over time, the Ft mutant ovary formed very few primordial or primary follicles, which contained oocytes that failed to grow and were surrounded by scarce granulosa cells that expressed low levels of FOXL2. By 3 wk after transplantation, it was difficult to identify ovarian tissue in Ft mutant ovary transplants. In summary, we conclude that the Ft locus contains genes essential for somatic-germ cell interactions, without which the germ cell niche fails to mature in both sexes. PMID:21293032

Kim, Bongki; Kim, Youngha; Cooke, Paul S; Rüther, Ulrich; Jorgensen, Joan S

2011-05-01

105

Colleges Put the Squeeze on Germs  

ERIC Educational Resources Information Center

A spirited campaign to promote "hand hygiene" is under way at the University of Central Florida Orlando campus, and the urinal toter, known as UCF 5th Guy, is its front line. Like their counterparts at many other institutions, health officials at Central Florida want students to think about the germs that lurk on their hands. And then clean them,…

Sander, Libby

2008-01-01

106

UTILIZING CORN GERM MEAL IN PLYWOOD GLUE  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to evaluate the potential of corn germ meal as protein extender in plywood adhesive. This research is part of our laboratory’s efforts to develop new uses for the proteinaceous co-products from cereal and soybean processing. We were previously successful in formulating a s...

107

Germ-line transformation of Arabidopsis lasiocarpa  

Microsoft Academic Search

In planta transformation methods have opened up the possibility of transforming plant species for which no regeneration protocols currently exist. In this study, the suitability of the germ-line transformation method developed for Arabidopsis thaliana was examined for four taxa in the Brassicaceae that have not been previously transformed: Arabidopsis griffithiana, Arabidopsis lasiocarpa, Arabidopsis petraea and Capsella bursa-pastoris. Numerous transformants were

Brian W. Tague

2001-01-01

108

Cutaneous metastasis from testicular germ cell tumour  

PubMed Central

The skin is an unusual site of metastases from solid organ malignancies. We report the case of a patient with a malignant mixed non-seminomatous germ cell tumor of the testis, presenting with cutaneous metastasis, which was treated with salvage chemotherapy. PMID:24497691

Joel, Anjana; Bhatt, Amit Dilip; Samuel, Abraham; Chacko, Raju Titus

2014-01-01

109

Benign neck metastasis of a testicular germ cell tumor.  

PubMed

Germ cell tumors (GCTs) are relatively rare neoplasms considered to be curable malignancies since the introduction of cisplatin. The presence of neck metastasis has been reported, with fewer reports of metastatic mature teratoma. In this study, 3 cases of "benign neck" metastasis in patients with GCT between 1998 and 2010 were reviewed retrospectively. In all 3 cases the presenting clinical sign was a left lower neck mass, leading to the diagnosis of the primary site in the testis. All had surgical salvage following chemotherapy, with benign lesions or mature teratoma in histopathology of the neck mass. Chemotherapy was followed by salvage lower-half neck dissection showing benign features in the neck specimen, even though malignancy was proven histologically in other areas. Only 1 patient had a postoperative chyle leak, which resolved spontaneously after several days. Neck dissection is recommended in those patients because malignancy cannot be excluded. PMID:25594657

Gavriel, Haim; Kleid, Stephen

2015-01-01

110

The Biology of the Germ line in Echinoderms  

PubMed Central

SUMMARY The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

Wessel, Gary M.; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A.; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S. Zachary; Yajima, Mamiko; Zazueta, Vanessa

2014-01-01

111

INTRODUCTION The mesodermal germ layer contributes cells to the notochord,  

E-print Network

into the marginal zone of a single blastomere of Xenopus laevis embryos at the 4 cell stage. Morpholino experiments Britain © The Company of Biologists Limited 2002 DEV1817 Xenopus laevis has been a particularly useful (Harland and Gerhart, 1997). In Xenopus, mesoderm is induced around the equator of the embryo

Amaya, Enrique

112

Germ cell tumors of the CNS in children: recent advances in therapy  

Microsoft Academic Search

Primary germ cell tumors of the central nervous system are rare neoplasms, accounting for no more than 2% of all malignancies\\u000a in children and young people under 20 in the Western hemisphere. They have unique features related to age at diagnosis and\\u000a sites of origin, as well as race and gender predilection. Prognosis has been clearly shown to be strongly

Blanca Diez; Casilda Balmaceda; Matsao Matsutani; H. L. Weiner

1999-01-01

113

Current advances in the diagnosis and management of intracranial germ cell tumors  

Microsoft Academic Search

Central nervous system (CNS) germ cell tumors (GCT) account for less than 5% of primary brain tumors in children and young\\u000a adults, but they continue to attract much attention. Over the past decade, two advances have led to re-evaluation of what\\u000a constitutes conventional therapy for CNS GCT. For pure germinomas, the challenge remains the determination of the optimal\\u000a field and

Casilda Balmaceda; Jonathan Finlay

2004-01-01

114

Germ Cell Development in the Scleractinian Coral Euphyllia ancora (Cnidaria, Anthozoa)  

PubMed Central

Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs. PMID:22848529

Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

2012-01-01

115

Germ cell development in the scleractinian coral Euphyllia ancora (Cnidaria, Anthozoa).  

PubMed

Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs. PMID:22848529

Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

2012-01-01

116

Germ cell cluster organization and oogenesis in the tardigrade Dactylobiotus parthenogeneticus Bertolani, 1982 (Eutardigrada, Murrayidae).  

PubMed

Germ cell cluster organization and the process of oogenesis in Dactylobiotus parthenogeneticus have been described using transmission electron microscopy and light microscopy. The reproductive system of D. parthenogeneticus is composed of a single, sac-like, meroistic ovary and a single oviduct that opens into the cloaca. Two zones can be distinguished in the ovary: a small germarium that is filled with oogonia and a vitellarium that is filled with germ cell clusters. The germ cell cluster, which has the form of a modified rosette, consists of eight cells that are interconnected by stable cytoplasmic bridges. The cell that has the highest number of stable cytoplasmic bridges (four bridges) finally develops into the oocyte, while the remaining cells become trophocytes. Vitellogenesis of a mixed type occurs in D. parthenogeneticus. One part of the yolk material is produced inside the oocyte (autosynthesis), while the second part is synthesized in the trophocytes and transported to the oocyte through the cytoplasmic bridges. The eggs are covered with two envelopes: a thin vitelline envelope and a three-layered chorion. The surface of the chorion forms small conical processes, the shape of which is characteristic for the species that was examined. In our paper, we present the first report on the rosette type of germ cell clusters in Parachela. PMID:25433446

Poprawa, Izabela; Hyra, Marta; Rost-Roszkowska, Magdalena Maria

2014-11-30

117

Combination Chemotherapy in Treating Young Patients With Recurrent or Resistant Malignant Germ Cell Tumors  

ClinicalTrials.gov

Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Ovarian Choriocarcinoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Testicular Choriocarcinoma; Testicular Choriocarcinoma and Embryonal Carcinoma; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma; Testicular Embryonal Carcinoma and Yolk Sac Tumor; Testicular Yolk Sac Tumor

2014-03-18

118

Mechanisms controlling primary and new production in a global ecosystem model Part I: The role of the large-scale upper mixed layer variability  

NASA Astrophysics Data System (ADS)

A global general circulation model coupled to a simple six-compartment ecosystem model is used to study the extent to which global variability in primary and export production can be realistically predicted on the basis of advanced parameterizations of upper mixed layer physics, without recourse to introducing extra complexity in model biology. The ''K profile parameterization'' (KPP) scheme employed, combined with 6-hourly external forcing, is able to capture short-term periodic and episodic events such as diurnal cycling and storm-induced deepening. The model realistically reproduces various features of global ecosystem dynamics that have been problematic in previous global modelling studies, using a single generic parameter set. The realistic simulation of deep convection in the North Atlantic, and lack of it in the North Pacific and Southern Oceans, leads to good predictions of chlorophyll and primary production in these contrasting areas. Realistic levels of primary production are predicted in the oligotrophic gyres due to high frequency external forcing of the upper mixed layer (accompanying paper Popova et al., 2006) and novel parameterizations of zooplankton excretion. Good agreement is shown between model and observations at various JFOFS time series sites: BATS, KERFIX, Papa and station India. One exception is that the high zooplankton grazing rates required to maintain low chlorophyll in high-nutrient low-chlorophyll and oligotrophic systems lessened agreement between model and data in the northern North Atlantic, where mesozooplankton with lower grazing rates may be dominant. The model is therefore not globally robust in the sense that additional parameterizations were needed to realistically simulate ecosystem dynamics in the North Atlantic. Nevertheless, the work emphasises the need to pay particular attention to the parameterization of mixed layer physics in global ocean ecosystem modelling as a prerequisite to increasing the complexity of ecosystem models.

Popova, E. E.; Coward, A. C.; Nurser, G. A.; de Cuevas, B.; Fasham, M. J. R.; Anderson, T. R.

2006-07-01

119

Synchronous Chaos and Broad Band Gamma Rhythm in a Minimal Multi-Layer Model of Primary Visual Cortex  

PubMed Central

Visually induced neuronal activity in V1 displays a marked gamma-band component which is modulated by stimulus properties. It has been argued that synchronized oscillations contribute to these gamma-band activity. However, analysis of Local Field Potentials (LFPs) across different experiments reveals considerable diversity in the degree of oscillatory behavior of this induced activity. Contrast-dependent power enhancements can indeed occur over a broad band in the gamma frequency range and spectral peaks may not arise at all. Furthermore, even when oscillations are observed, they undergo temporal decorrelation over very few cycles. This is not easily accounted for in previous network modeling of gamma oscillations. We argue here that interactions between cortical layers can be responsible for this fast decorrelation. We study a model of a V1 hypercolumn, embedding a simplified description of the multi-layered structure of the cortex. When the stimulus contrast is low, the induced activity is only weakly synchronous and the network resonates transiently without developing collective oscillations. When the contrast is high, on the other hand, the induced activity undergoes synchronous oscillations with an irregular spatiotemporal structure expressing a synchronous chaotic state. As a consequence the population activity undergoes fast temporal decorrelation, with concomitant rapid damping of the oscillations in LFPs autocorrelograms and peak broadening in LFPs power spectra. We show that the strength of the inter-layer coupling crucially affects this spatiotemporal structure. We predict that layer VI inactivation should induce global changes in the spectral properties of induced LFPs, reflecting their slower temporal decorrelation in the absence of inter-layer feedback. Finally, we argue that the mechanism underlying the emergence of synchronous chaos in our model is in fact very general. It stems from the fact that gamma oscillations induced by local delayed inhibition tend to develop chaos when coupled by sufficiently strong excitation. PMID:21998568

Battaglia, Demian; Hansel, David

2011-01-01

120

Susceptibility Alleles for Testicular Germ Cell Tumor  

Microsoft Academic Search

\\u000a A family history of Testicular Germ Cell Tumor (TGCT) is among the strongest and most well-documented risk factors for TGCT\\u000a (Forman et al. 1992; Westergaard et al. 1996; Heimdal et al. 1996; Sonneveld et al. 1999; Hemminki and Li 2004). In a proportion\\u000a of cases (?2%), a first-degree family member is also affected with the disease (Forman et al. 1992).

Elizabeth A. Rapley

121

Fluxes of carbon and nutrients to the Iceland Sea surface layer and inferred primary productivity and stoichiometry  

NASA Astrophysics Data System (ADS)

Fluxes of carbon and nutrients to the upper 100 m of the Iceland Sea are evaluated. The study utilises hydro-chemical data from the Iceland Sea time-series station (68.00° N, 12.67° W), for the years between 1993 and 2006. By comparing data of dissolved inorganic carbon (DIC) and nutrients in the surface layer (upper 100 m), and a sub-surface layer (100-200 m), we calculate monthly deficits in the surface, and use these to deduce the surface layer fluxes that affect the deficits: vertical mixing, horizontal advection, air-sea exchange, and biological activity. The deficits show a clear seasonality with a minimum in winter, when the mixed layer is at the deepest, and a maximum in early autumn, when biological uptake has removed much of the nutrients. The annual vertical fluxes of DIC and nitrate amounts to 1.7 ± 0.3 and 0.23 ± 0.07 mol m-2 yr-1, respectively, and the annual air-sea uptake of atmospheric CO2 is 4.4 ± 1.1 mol m-2 yr-1. The biologically driven changes in DIC during the year relates to net community production (NCP), and the net annual NCP corresponds to export production, and is here calculated to 6.1 ± 0.9 mol C m-2 yr-1. The typical, median C : N ratio during the period of net community uptake is 11, and thus clearly higher than Redfield, but is varying during the season.

Jeansson, E.; Bellerby, R. G. J.; Skjelvan, I.; Frigstad, H.; Ólafsdóttir, S. R.; Ólafsson, J.

2014-11-01

122

Overview of the Graphical User Interface for the GERM Code (GCR Event-Based Risk Model  

NASA Technical Reports Server (NTRS)

The descriptions of biophysical events from heavy ions are of interest in radiobiology, cancer therapy, and space exploration. The biophysical description of the passage of heavy ions in tissue and shielding materials is best described by a stochastic approach that includes both ion track structure and nuclear interactions. A new computer model called the GCR Event-based Risk Model (GERM) code was developed for the description of biophysical events from heavy ion beams at the NASA Space Radiation Laboratory (NSRL). The GERM code calculates basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at NSRL for the purpose of simulating space radiobiological effects. For mono-energetic beams, the code evaluates the linear-energy transfer (LET), range (R), and absorption in tissue equivalent material for a given Charge (Z), Mass Number (A) and kinetic energy (E) of an ion. In addition, a set of biophysical properties are evaluated such as the Poisson distribution of ion or delta-ray hits for a specified cellular area, cell survival curves, and mutation and tumor probabilities. The GERM code also calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle. The contributions from primary ion and nuclear secondaries are evaluated. The GERM code accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections, and has been used by the GERM code for application to thick target experiments. The GERM code provides scientists participating in NSRL experiments with the data needed for the interpretation of their experiments, including the ability to model the beam line, the shielding of samples and sample holders, and the estimates of basic physical and biological outputs of the designed experiments. We present an overview of the GERM code GUI, as well as providing training applications.

Kim, Myung-Hee; Cucinotta, Francis A.

2010-01-01

123

Regulation of germ cell meiosis in the fetal ovary.  

PubMed

Fertility depends on correct regulation of meiosis, the special form of cell division that gives rise to haploid gametes. In female mammals, germ cells enter meiosis during fetal ovarian development, while germ cells in males avoid entering meiosis until puberty. Decades of research have shown that meiotic entry, and germ cell sex determination, are not initiated intrinsically within the germ cells. Instead, meiosis is induced by signals produced by the surrounding somatic cells. More recently, retinoic acid (RA), the active derivative of vitamin A, has been implicated in meiotic induction during fetal XX and postnatal XY germ cell development. Evidence for an intricate system of RA synthesis and degradation in the fetal ovary and testis has emerged, explaining past observations of infertility in vitamin A-deficient rodents. Here we review how meiosis is triggered in fetal ovarian germ cells, paying special attention to the role of RA in this process. PMID:23417400

Spiller, Cassy M; Bowles, Josephine; Koopman, Peter

2012-01-01

124

Spike Firing and IPSPs in Layer V Pyramidal Neurons during Beta Oscillations in Rat Primary Motor Cortex (M1) In Vitro  

PubMed Central

Beta frequency oscillations (10–35 Hz) in motor regions of cerebral cortex play an important role in stabilising and suppressing unwanted movements, and become intensified during the pathological akinesia of Parkinson's Disease. We have used a cortical slice preparation of rat brain, combined with concurrent intracellular and field recordings from the primary motor cortex (M1), to explore the cellular basis of the persistent beta frequency (27–30 Hz) oscillations manifest in local field potentials (LFP) in layers II and V of M1 produced by continuous perfusion of kainic acid (100 nM) and carbachol (5 µM). Spontaneous depolarizing GABA-ergic IPSPs in layer V cells, intracellularly dialyzed with KCl and IEM1460 (to block glutamatergic EPSCs), were recorded at ?80 mV. IPSPs showed a highly significant (P< 0.01) beta frequency component, which was highly significantly coherent with both the Layer II and V LFP oscillation (which were in antiphase to each other). Both IPSPs and the LFP beta oscillations were abolished by the GABAA antagonist bicuculline. Layer V cells at rest fired spontaneous action potentials at sub-beta frequencies (mean of 7.1+1.2 Hz; n?=?27) which were phase-locked to the layer V LFP beta oscillation, preceding the peak of the LFP beta oscillation by some 20 ms. We propose that M1 beta oscillations, in common with other oscillations in other brain regions, can arise from synchronous hyperpolarization of pyramidal cells driven by synaptic inputs from a GABA-ergic interneuronal network (or networks) entrained by recurrent excitation derived from pyramidal cells. This mechanism plays an important role in both the physiology and pathophysiology of control of voluntary movement generation. PMID:24465488

Lacey, Michael G.; Gooding-Williams, Gerard; Prokic, Emma J.; Yamawaki, Naoki; Hall, Stephen D.; Stanford, Ian M.; Woodhall, Gavin L.

2014-01-01

125

Changes in Brain Function in Patients With Stage I, Stage II, Stage III, or Stage IV Ovarian, Primary Peritoneal, or Fallopian Tube Cancer Who Are Receiving Chemotherapy  

ClinicalTrials.gov

Cognitive Side Effects of Cancer Therapy; Malignant Ovarian Mixed Epithelial Tumor; Malignant Ovarian Surface Epithelial-Stromal Tumor; Ovarian Brenner Tumor; Ovarian Carcinosarcoma; Ovarian Choriocarcinoma; Ovarian Clear Cell Cystadenocarcinoma; Ovarian Dysgerminoma; Ovarian Embryonal Carcinoma; Ovarian Endometrioid Adenocarcinoma; Ovarian Mixed Germ Cell Tumor; Ovarian Mucinous Cystadenocarcinoma; Ovarian Polyembryoma; Ovarian Sarcoma; Ovarian Serous Cystadenocarcinoma; Ovarian Teratoma; Ovarian Yolk Sac Tumor; Stage I Ovarian Cancer; Stage IA Fallopian Tube Cancer; Stage IA Ovarian Cancer; Stage IA Ovarian Germ Cell Tumor; Stage IB Fallopian Tube Cancer; Stage IB Ovarian Cancer; Stage IB Ovarian Germ Cell Tumor; Stage IC Fallopian Tube Cancer; Stage IC Ovarian Cancer; Stage IC Ovarian Germ Cell Tumor; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIA Ovarian Cancer; Stage IIA Ovarian Germ Cell Tumor; Stage IIB Fallopian Tube Cancer; Stage IIB Ovarian Cancer; Stage IIB Ovarian Germ Cell Tumor; Stage IIC Fallopian Tube Cancer; Stage IIC Ovarian Cancer; Stage IIC Ovarian Germ Cell Tumor; Stage IIIA Fallopian Tube Cancer; Stage IIIA Ovarian Cancer; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIA Primary Peritoneal Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIB Ovarian Cancer; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIB Primary Peritoneal Cancer; Stage IIIC Fallopian Tube Cancer; Stage IIIC Ovarian Cancer; Stage IIIC Ovarian Germ Cell Tumor; Stage IIIC Primary Peritoneal Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Ovarian Germ Cell Tumor; Stage IV Primary Peritoneal Cancer; Undifferentiated Ovarian Carcinoma

2014-12-23

126

Embryonic stem cells can form germ cells in vitro  

Microsoft Academic Search

Knock-in embryonic stem (ES) cells, in which GFP or lacZ was expressed from the endogenous mouse vasa homolog (Mvh), which is specifically expressed in differentiating germ cells, were used to visualize germ cell production during in vitro differentiation. The appearance of MVH-positive germ cells depended on embryoid body formation and was greatly enhanced by the inductive effects of bone morphogenic

Yayoi Toyooka; Naoki Tsunekawa; Ryuko Akasu; Toshiaki Noce

2003-01-01

127

Entry of Mouse Embryonic Germ Cells into Meiosis  

Microsoft Academic Search

Germ cells harvested from mouse embryonic genital ridges were mixed with disaggregated embryonic lung cells, and the reaggregates were cultured for 4–7 days. Germ cells derived from female embryos 10.5–13.5 days postcoitum (dpc) entered and progressed through meiotic prophasein vitroasin vivo,although with a 12- to 24-hr delay. If the cultures were maintained for 2–3 weeks, the germ cells developed into

A. McLaren; D. Southee

1997-01-01

128

A bilateral primary yolk sac tumor of the lung associated with chromosome 3 polysomy  

PubMed Central

Extragonadal germ cell tumors (EGCTs) in the lung are extremely rare and their pathogenesis is poorly understood. We report a case in a 48-year-old female which was very aggressive and stained positive for primoridial germ cell markers. Interestingly, there was chromosome 3 polysomy noted. To our knowledge this is the first chromosomal aberration noted in a primary germ cell tumor of the lung. PMID:23114647

Arora, Shitij; Patel, Harish; Mir, Pervez; Mishra, Sneha; Kalra, Amita; Sawhney, Harinder; Duffoo, Frantz; Macera, Mike; Abdu, Afaf; Thelmo, William

2013-01-01

129

Microsurgical removal of epidermal and cortical cells: evidence that the gravitropic signal moves through the outer cell layers in primary roots of maize  

NASA Technical Reports Server (NTRS)

There is general agreement that during root gravitropism some sort of growth-modifying signal moves from the cap to the elongation zone and that this signal ultimately induces the curvature that leads to reorientation of the root. However, there is disagreement regarding both the nature of the signal and the pathway of its movement from the root cap to the elongation zone. We examined the pathway of movement by testing gravitropism in primary roots of maize (Zea mays L.) from which narrow (0.5 mm) rings of epidermal and cortical tissue were surgically removed from various positions within the elongation zone. When roots were girdled in the apical part of the elongation zone gravitropic curvature occurred apical to the girdle but not basal to the girdle. Filling the girdle with agar allowed curvature basal to the girdle to occur. Shallow girdles, in which only two or three cell layers (epidermis plus one or two cortical cell layers) were removed, prevented or greatly delayed gravitropic curvature basal to the girdle. The results indicate that the gravitropic signal moves basipetally through the outermost cell layers, perhaps through the epidermis itself.

Yang, R. L.; Evans, M. L.; Moore, R.

1990-01-01

130

The epigenetic regulator PLZF represses L1 retrotransposition in germ and progenitor cells  

PubMed Central

Germ cells and adult stem cells maintain tissue homeostasis through a finely tuned program of responses to both physiological and stress-related signals. PLZF (Promyelocytic Leukemia Zinc Finger protein), a member of the POK family of transcription factors, acts as an epigenetic regulator of stem cell maintenance in germ cells and haematopoietic stem cells. We identified L1 retrotransposons as the primary targets of PLZF. PLZF-mediated DNA methylation induces silencing of the full-length L1 gene and inhibits L1 retrotransposition. Furthermore, PLZF causes the formation of barrier-type boundaries by acting on inserted truncated L1 sequences in protein coding genes. Cell stress releases PLZF-mediated repression, resulting in L1 activation/retrotransposition and impaired spermatogenesis and myelopoiesis. These results reveal a novel mechanism of action by which, PLZF represses retrotransposons, safeguarding normal progenitor homeostasis. PMID:23727884

Puszyk, William; Down, Thomas; Grimwade, David; Chomienne, Christine; Oakey, Rebecca J; Solomon, Ellen; Guidez, Fabien

2013-01-01

131

Human primordial germ cell-derived progenitors give rise to neurons and glia in vivo  

SciTech Connect

We derived a cell population from cultured human primordial germ cells from early human embryos. The derivates, termed embryoid body-derived (EBD) cells, displayed an extensive capacity for proliferation and expressed a panel of markers in all three germ layers. Interestingly, EBD cells were also positive for markers of neural stem/progenitor cells, such as nestin and glial fibrillary acidic protein. When these cells were transplanted into the brain cavities of fetal sheep and postnatal NOD-SCID mice or nerve-degenerated tibialis anterior muscles, they readily gave rise to neurons or glial cells. To our knowledge, our data are the first to demonstrate that EBD cells can undergo further neurogenesis under suitable environments in vivo. Hence, with the abilities of extensive expansion, self-renewal, and differentiation, EBD cells may provide a useful donor source for neural stem/progenitor cells to be used in cell-replacement therapies for diseases of the nervous system.

Teng, Yincheng [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)] [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China); Chen, Bin [Center for Developmental Biology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, 1665 Kong Jiang Road, Shanghai 200092 (China)] [Center for Developmental Biology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, 1665 Kong Jiang Road, Shanghai 200092 (China); Tao, Minfang, E-mail: Taomf@126.com [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)] [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)

2009-12-18

132

Pathology of testicular germ cell tumors.  

PubMed

The pathology report on a testicular germ cell tumor should include the following information: Tumor type: The histologic type of tumor present. If the tumor is of mixed type, the components should be listed, in order of relative abundance. The pathologist may endeavor to give a numeric estimate of the percentages of each element. Staging information: The size of the tumor should be listed. Local spread--into rete testis, tunica albuginea, epididymis, and spermatic cord--should be listed. If the cord is involved, possible involvement of its surgical resection margin should be assessed. Vascular/lymphatic invasion should be assessed for its presence or absence. Status of the remainder of the testis: Evidence of cryptorchidism or other dysgenetic features should be mentioned. Such features may imply a greater risk for the development of a contralateral tumor. Also, the presence of normal spermatogenesis elsewhere in the uninvolved testis should be reported. This finding may suggest a relatively decreased risk for contralateral tumor development and is a likely indicator of fertility should the patient consider sperm banking prior to retroperitoneal surgery and chemotherapy. The finding of mature sperm in the epididymis is an easy way to confirm spermatogenesis in the testis. Incidental findings: Lipomas or hydroceles of the cord, adrenal rests, and adnexal cysts may be found. The pathologist plays a crucial role in the diagnosis of germ cell tumors. In addition to elucidating tumor type, the pathologist is relied upon for precise local staging and for the classification of metastases, all of which have important implications in determining optimal therapy. As the clinical management of germ cell tumors evolves, the pathologist will continue to play a role in defining those features that have a bearing on patient outcome. PMID:1663935

Brodsky, G L

1991-12-01

133

Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs  

NASA Technical Reports Server (NTRS)

Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

Wakahara, M.; Neff, A. W.; Malacinski, G. M.

1984-01-01

134

In vitro culture and transposon-mediated genetic modification of chicken primordial germ cells   

E-print Network

Primordial germ cells (PGCs) are the embryonic precursors of the germ cell lineage. Segregation of the chicken germ line from somatic cells occurs very early in embryonic development. By day two of incubation chicken ...

Macdonald, Joni

2012-06-30

135

Predisposition alleles for Testicular Germ Cell Tumour.  

PubMed

For some time, it has been known that there is a substantial genetic component to testicular germ cell tumour susceptibility, supported by several pieces of evidence, including the significantly increased familial risk and differential risk among races. However, despite extensive linkage searches on available families, no high penetrance genes have been identified. Recently genome-wide association studies have revealed three candidate loci, which confer up to a four-fold risk of developing TGCT. The genome-wide association studies for this cancer are noteworthy, because of the high effect sizes demonstrated at each loci and the biological plausibility of the genes at or near the associated SNPs, particularly KITLG. PMID:20303738

Rapley, Elizabeth A; Nathanson, Katherine L

2010-06-01

136

The fascinating germ theories on cancer pathogenesis.  

PubMed

For more than 100 years, the germ theory of cancer, proposing that microorganisms were at the origin of the disease, dominated medicine. Several eminent scientists like Etienne Burnet, Mikhail Stepanovich Voronin, Charles-Louis Malassez, and Francis-Peyton Rous argued on the pathogenesis presenting their theories that implicated cocci, fungi and parasites. The impact of these theories was culminated by the Nobel Prize in 1926 that was attributed to the Danish scientist Johannes Fibiger for his work on the nematode Spiroptera as a causative agent in cancer. Even if those theories were the result of fantasy and misinterpretation, they paved the way for the scientific research in oncology. PMID:24659685

Tsoucalas, G; Laios, K; Karamanou, M; Gennimata, V; Androutsos, G

2014-01-01

137

The dendrites of granule cell layer neurons are the primary injury sites in the "Brain Diabetes" rat.  

PubMed

We previously demonstrated that rats that receive dorsal third ventricle (3V) streptozotocin (STZ) injections (STZ-3V-rats) exhibit cognitive decline as measured by the Morris Water Maze (MWM) and can be used as an animal model of Alzheimer's disease (AD). Immunohistochemical studies of the hippocampal formations of these animals have revealed significant changes in cerebral insulin signalling pathways, as well as marked increases of amyloid beta (Ab) deposition. Here, we performed Sholl analyses of granule cell layer dendrites and measured dendrite spine densities to assess the effect of STZ on hippocampal morphology. In STZ-3V rats as the results, more branching, complex dendrite arborisation, and increased soma size of the granule cells were observed, while spine densities were decreased in all three spine types. An intraventricular injection of a long-acting insulin analogue improved STZ-induced behavioural and immunohistochemical changes. Nevertheless, dendrite spine densities remained diminished, presumably due to overall null changes since new spine formation due to insulin stimulation has been compensated by loss of old spines. It is concluded that cognitive decline in the "Brain Diabetes" rats is primarily due to impaired intracerebral insulin signalling and the ultimate results were injured excitatory inputs through the perforant pathway. PMID:25476563

Shingo, Akiko Sheala; Mervis, Ronald F; Kanabayashi, Tomomichi; Kito, Shozo; Murase, Toshio

2015-03-01

138

Inverted Impacted Primary Maxillary Incisors: A Case Report  

PubMed Central

Tooth impaction rarely occurs in primary dentition. Most of the primary teeth impactions are seen in second molars. The purpose of this article is to present a 4-year-old girl with bilateral impaction of inverted primary maxillary central incisors which trauma had displaced their tooth germ before erupting. PMID:23066483

Seraj, B.; Ghadimi, S.; Mighani, G.; Zare, H.; Rabbani, M.

2012-01-01

139

Pediatric germ cell tumors presenting beyond childhood?  

PubMed

Four cases are reported meeting the criteria of a pediatric (i.e., Type I) testicular germ cell tumor (TGCT), apart from the age of presentation, which is beyond childhood. The tumors encompass the full spectrum of histologies of pediatric TGCT: teratoma, yolk sac tumor, and various combinations of the two, and lack intratubular germ cell neoplasia/carcinoma in situ in the adjacent parenchyma. The neoplasms are (near)diploid, and lack gain of 12p, typical for seminomas and non-seminomas of the testis of adolescents and adults (i.e., Type II). It is proposed that these neoplasms are therefore late appearing pediatric (Type I) TGCT. The present report broadens the concept of earlier reported benign teratomas of the post-pubertal testis to the full spectrum of pediatric TGCT. The possible wide age range of pediatric TGCT, demonstrated in this study, lends credence to the concept that TGCT should according to their pathogenesis be classified into the previously proposed types. This classification is clinically relevant, because Type I mature teratomas are benign tumors, which are candidates for testis conserving surgery, as opposed to Type II mature teratomas, which have to be treated as Type II (malignant) non-seminomas. PMID:25427839

Oosterhuis, J W; Stoop, J A; Rijlaarsdam, M A; Biermann, K; Smit, V T H B M; Hersmus, R; Looijenga, L H J

2014-11-27

140

Cellular Mechanics of Germ Band Retraction in Drosophila  

PubMed Central

Germ band retraction involves a dramatic rearrangement of the tissues on the surface of the Drosophila embryo. As germ band retraction commences, one tissue, the germ band, wraps around another, the amnioserosa. Through retraction the two tissues move cohesively as the highly elongated cells of the amnioserosa contract and the germ band moves so it is only on one side of the embryo. To understand the mechanical drivers of this process, we designed a series of laser ablations that suggest a mechanical role for the amnioserosa. First, we find that during mid retraction, segments in the curve of the germ band are under anisotropic tension. The largest tensions are in the direction in which the amnioserosa contracts. Second, ablating one lateral flank of the amnioserosa reduces the observed force anisotropy and leads to retraction failures. The other intact flank of amnioserosa is insufficient to drive retraction, but can support some germ band cell elongation and is thus not a full phenocopy of ush mutants. Another ablation-induced failure in retraction can phenocopy mys mutants, and does so by targeting amnioserosa cells in the same region where the mutant fails to adhere to the germ band. We conclude that the amnioserosa must play a key, but assistive, mechanical role that aids uncurling of the germ band. PMID:24135149

Lynch, Holley E.; Crews, Sarah M.; Rosenthal, Brett; Kim, Elliott; Gish, Robert; Echiverri, Karl; Hutson, M. Shane

2013-01-01

141

Germ cell transplantation in an azoospermic Klinefelter bull.  

PubMed

Germ cell transplantation is a technique that transfers donor testicular cells into recipient testes. A population of germ cells can colonize the recipient testis, initiate spermatogenesis, and produce sperm capable of fertilization. In the present study, a nonmosaic Klinefelter bull was used as a germ cell recipient. The donor cell suspension was introduced into the rete testis using ultrasound-guided puncture. A pulsatile administration of GnRH was performed to stimulate spermatogenesis. The molecular approach to detect donor cells was done by a quantitative polymerase chain reaction with allele discrimination based on a genetic mutation between donor and recipient. Therefore, a known genetic mutation, associated with coat-color phenotype, was used to calculate the ratio of donor to recipient cells in the biopsy specimens and ejaculates for 10 mo. After slaughtering, meiotic preparations were performed. The injected germ cells did not undergo spermatogenesis. Six months after germ cell transplantation, the donor cells were rejected, which indicates that the donor cells could not incorporate in the testis. The hormone stimulation showed that the testosterone-producing Leydig cells were functionally intact. Despite subfertility therapy, neither the recipient nor the donor cells underwent spermatogenesis. Therefore, nonmosaic Klinefelter bulls are not suitable as germ cell recipients. Future germ cell recipients in cattle could be mosaic Klinefelters, interspecies hybrids, bulls with Sertoli cell-only syndrome, or bulls with disrupted germ cell migration caused by RNA interference. PMID:12930718

Joerg, Hannes; Janett, Fredi; Schlatt, Stefan; Mueller, Simone; Graphodatskaya, Daria; Suwattana, Duangsmorn; Asai, Mika; Stranzinger, Gerald

2003-12-01

142

Conserved Role of nanos Proteins in Germ Cell Development  

Microsoft Academic Search

In Drosophila, maternally supplied Nanos functions in the migration of primordial germ cells (PGCs) into the gonad; in mice, zygotic genes are involved instead. We report the cloning and the functional analyses of nanos2 and nanos3 in mice. These genes are differentially expressed in mouse PGCs. nanos2 is predominantly expressed in male germ cells, and the elimination of this gene

Masayuki Tsuda; Yumiko Sasaoka; Makoto Kiso; Kuniya Abe; Seiki Haraguchi; Satoru Kobayashi; Yumiko Saga

2003-01-01

143

Introduction Germ cell segregation is an important problem in  

E-print Network

, as it addresses how the fundamental distinctions between germ cells and somatic cells are initiated and maintained somatic cells, often long before the somatic gonads are formed. However, there has been a history are summarised in Box 1. In some species, germ cells can easily be identified very early in embryogenesis, when

Extavour, Cassandra

144

Hand WashingHand Washing Germ Fighting 101  

E-print Network

Hand WashingHand Washing Germ Fighting 101 Hand washing may be a simple task, but it is extremely important in preventing the spread of contagious illnesses. Wash your hands often to remove disease-causing germs. Wash your hands: Wet hands with warm water. When warm water isn't available, wash for a longer

145

Hand WashingHand Washing Germ Fighting 101  

E-print Network

Hand WashingHand Washing Germ Fighting 101 Hand washing may be a simple task, but it is extremely important in preventing the spread of contagious illnesses in child-care settings. Wash your hands often to remove disease-causing germs. Wash your hands upon arrival to the child-care setting in addition to: Wet

146

Genetic Control of Male Germ Unit Organization in Arabidopsis  

Microsoft Academic Search

In flowering plants, the vegetative nucleus and the two sperm cells are proposed to form a functional assemblage, the male germ unit (MGU). Here, we describe the developmental pathway of MGU assembly in Arabidopsis and report two classes of mutations that affect the integrity and\\/or the positioning of the MGU in the mature pollen grain. In germ unit malformed (gum)

Eric Lalanne; David Twell

2002-01-01

147

Germ cell selection in genetic mosaics in Drosophila melanogaster  

E-print Network

of the haploinsufficient Minute mutations in cells of the wing of Drosophila melanogaster (2). Mutations, which mayGerm cell selection in genetic mosaics in Drosophila melanogaster Cassandra Extavour* and Antonio). Gametic (sperm) selection in Drosophila (4) and other organisms (5, 6) has been described, as well as germ

Extavour, Cassandra

148

EDITORIAL INTRODUCTION [TO FEMALE GERM CELLS: BIOLOGY AND GENETIC RISK  

EPA Science Inventory

This is an editorial introduction to the special issue of utation Research, titled, emale Germ Cells: Biology and Genetic isk, which is an attempt to present a collection of papers that emphasize the distinct properties of female germ cells and their characteristic response to mu...

149

Alvocidib and Oxaliplatin With or Without Fluorouracil and Leucovorin Calcium in Treating Patients With Relapsed or Refractory Germ Cell Tumors  

ClinicalTrials.gov

Recurrent Extragonadal Seminoma; Recurrent Malignant Extragonadal Germ Cell Tumor; Recurrent Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage III Testicular Cancer; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2015-01-30

150

Alvocidib and Oxaliplatin With or Without Fluorouracil and Leucovorin Calcium in Treating Patients With Relapsed or Refractory Germ Cell Tumors  

ClinicalTrials.gov

Recurrent Extragonadal Seminoma; Recurrent Malignant Extragonadal Germ Cell Tumor; Recurrent Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage III Testicular Cancer; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2015-01-05

151

Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to static vs. dynamic light exposure in upper mixed-layer summer sea waters  

NASA Astrophysics Data System (ADS)

Microbial plankton experience short-term fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, fast repetition rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a subtle disruption of the photoinhibition and photoacclimation processes associated with ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions.

Galí, M.; Simó, R.; Pérez, G. L.; Ruiz-González, C.; Sarmento, H.; Royer, S.-J.; Fuentes-Lema, A.; Gasol, J. M.

2013-12-01

152

Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to vertically-moving and static incubations in upper mixed-layer summer sea waters  

NASA Astrophysics Data System (ADS)

Microbial plankton experience fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically-moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, Fast Repetition Rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a disruption of the photoinhibition and photoacclimation processes associated to ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions.

Galí, M.; Simó, R.; Pérez, G. L.; Ruiz-González, C.; Sarmento, H.; Royer, S.-J.; Fuentes-Lema, A.; Gasol, J. M.

2013-05-01

153

Origin and development of the germ line in sea stars  

PubMed Central

This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors – vasa, nanos, piwi – and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line in how these animals can help in this research field. The review is not intended to be comprehensive – sea star reproduction has been studied over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

Wessel, Gary M.; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

2014-01-01

154

Origin and development of the germ line in sea stars.  

PubMed

This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors-vasa, nanos, piwi-and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line into how these animals can help in this research field. The review is not intended to be comprehensive-sea star reproduction has been studied for over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

Wessel, Gary M; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

2014-05-01

155

The Ter mutation in the dead end gene causes germ cell loss and testicular germ cell tumours  

E-print Network

cell (PGC) loss in all genetic backgrounds1 . Ter is also a potent modifier of spontaneous testicularThe Ter mutation in the dead end gene causes germ cell loss and testicular germ cell tumours and with a Dnd1-encoding transgene. Dnd1 is expressed in fetal gonads during the critical period when TGCTs

156

Identification of a germ cell marker gene, the dead end homologue, in Chinese sturgeon Acipenser sinensis.  

PubMed

Dead end (dnd) encodes an RNA-binding protein that is essential for primordial germ cell (PGC) migration and gametogenesis in vertebrates. In this study, a Chinese sturgeon Acipenser sinensis dead end homologue, designated Asdnd, was identified and characterized. The full-length cDNA of Asdnd was 1630base pairs (bp) and encoded a peptide of 396 amino acid residues. Multiple sequence alignment showed that AsDnd shared six conserved regions of Dnd orthologs, including the RNA recognition motif. Phylogenetic analysis revealed that AsDnd was grouped with teleosts. By quantitative real-time PCR analysis, the Asdnd transcripts were found to originate from the maternal parent and be specifically expressed in gonads of immature Chinese sturgeons of both sexes. Fluorescent in situ hybridization indicated that Asdnd transcripts were restricted to germ cells. In the testis, Asdnd was abundant in spermatogonia and tended to gradually diminish in late spermatogenic stages, while strong signals were found in primary oocytes, as opposed to oogonia, in the ovary. Zebrafish PGCs were clearly visualized at 24h post-fertilization by co-injecting RFP-Asdnd 3' UTR and GFP-nos3 3' UTR mRNA, indicating that dnd 3' UTR has a conserved function among teleosts. Therefore, dnd could serve as a germ cell marker in Chinese sturgeon. PMID:25550043

Yang, Xiaoge; Yue, Huamei; Ye, Huan; Li, Chuangju; Wei, Qiwei

2015-03-01

157

Procurement and Maintenance of Germ-Free Swine for Microbiological Investigations1  

PubMed Central

Germ-free swine were routinely procured by both hysterectomy and hysterotomy (Caesarian section). By means of light-weight portable equipment, piglets could be obtained and transported to the laboratory (without contamination) over distances in excess of 100 miles. The isolators employed in rearing were constructed of stainless steel and flexible plastic film. At weekly intervals, fecal swabs and waste from the floor of the isolator were cultured on blood-agar and in thioglycolate broth, as well as being examined microscopically for the presence of bacteria, yeast, and fungi. The presence of pleuropneumonia-like organisms (PPLO) and viruses in such material was not demonstrable, either by the use of enriched PPLO media or primary porcine-kidney cell cultures. Tissues, body fluids, and cecal contents of piglets sacrificed specifically for microbiological examination were also negative for PPLO, viruses, bacteria, yeast, and fungi. Prenatal infestations by ascarids were not observed. Nutritional problems related to rearing of germ-free piglets, such as hypoglycemia, were not encountered, and the use of an autoclaved commercial sow's milk replacer proved quite satisfactory. The temperature to which piglets were subjected during the first few days of life, however, was very important. The isolator design and application of gnotobiotic techniques to the procurement and rearing of a large germ-free animal such as the pig proved feasible and less difficult than anticipated. Images FIG. 1 FIG. 2 FIG. 3 FIG. 4 FIG. 5 FIG. 7 FIG. 8 FIG. 9 FIG. 10 FIG. 11 PMID:14199016

Meyer, R. C.; Bohl, E. H.; Kohler, E. M.

1964-01-01

158

Immunocytochemical localization of wheat germ agglutinin in wheat  

PubMed Central

Immunocytological techniques were developed to localize the plant lectin, wheat germ agglutinin (WGA), in the tissues and cells of wheat plants. In a previous study we demonstrated with a radioimmunoassay that the lectin is present in wheat embryos and adult plants both in the roots and at the base of the stem. We have now found, using rhodamine, peroxidase, and ferritin-labeled secondary antibodies, that WGA is located in cells and tissues that establish direct contact with the soil during germination and growth of the plant In the embryo, WGA is found in the surface layer of the radicle, the first adventitious roots, the coleoptile, and the scutellum. Although found throughout the coleorhiza and epiblast, it is at its highest levels within the cells at the surface of these organs. In adult plants, WGA is located only in the caps and tips of adventitious roots. Reaction product for WGA was not visualized in embryonic or adult leaves or in other tissues of adult plants. At the subcellular level, WGA is located at the periphery of protein bodies, within electron-translucent regions of the cytoplasm, and at the cell wall-protoplast interface. Since WGA is found at potential infection sites and is known to have fungicidal properties, it may function in the defense against fungal pathogens. PMID:7045136

1982-01-01

159

The Effect of Wheat Germ Extract on Premenstrual Syndrome Symptoms  

PubMed Central

Pre-menstrual syndrome is one of the most common disorders in women and impairs work and social relationships. Several treatment modalities have been proposed including herbal medicines. Considering the properties of wheat germ, this study aimed to determine the effects of wheat germ extract on the symptoms of premenstrual syndrome. This triple blind clinical trial was conducted on 84 women working in hospitals affiliated to Hamadan University of Medical Sciences. Subjects completed daily symptom record form for two consecutive months. After definitive diagnosis of premenstrual syndrome, they were randomly divided into two groups of 50 people. Then, for two consecutive months, 400 mg capsules of wheat germ extract or placebo were used three times a day, from day 16 until day 5 of the next menstrual cycle. Wheat germ significantly reduced physical symptoms (63.56%), psychological symptoms (66.30%), and the general score (64.99%). Although the severity of symptoms decreased in both groups, this reduction was more significant in the wheat germ extract group (p < 0.001). On the other hand, physical symptoms decreased only in the wheat germ extract (p < 0.001) and there was no statistically significant difference in the placebo group. No complications were observed in any of the groups. It seems that using wheat germ extract reduces general, psychological and physical symptoms. PMID:25561922

Ataollahi, Maryam; Akbari, Sedigheh Amir Ali; Mojab, Faraz; Alavi Majd, Hamid

2015-01-01

160

The making of a germ panic, then and now.  

PubMed Central

Over the last 2 decades, a heightened interest in germs has been evident in many aspects of American popular culture, including news coverage, advertisements, and entertainment media. Although clearly a response to the AIDS epidemic and other recent disease outbreaks, current obsessions with germs have some striking parallels with a similar period of intense anxiety about disease germs that occurred between 1900 and 1940. A comparison of these 2 periods of germ "panic" suggests some of the long-term cultural trends that contributed to their making. Both germ panics reflected anxieties about societal incorporation, associated with expanding markets, transportation networks, and mass immigration. They were also shaped by new trends in public health education, journalism, advertising, and entertainment media. In comparison to the first germ panic, the current discourse about the "revenge of the superbugs" is considerably more pessimistic because of increasing worries about the environment, suspicions of governmental authority, and distrust of expert knowledge. Yet, as popular anxieties about infectious disease have increased, public health scientists have been attracting favorable coverage in their role as "medical detectives" on the trail of the "killer germ." PMID:10667179

Tomes, N

2000-01-01

161

Sinonasal teratocarcinosarcoma with yolk sac elements: a neoplasm of somatic or germ cell origin?  

PubMed

Sinonasal teratocarcinosarcoma is an uncommon, aggressive, morphologically heterogenous tumor composed of cells derived from the 3 somatic layers. A histogenetic origin from a multipotential adult somatic stem cell with divergent differentiation has been favored over a germ cell origin. This assumption has been based on the lack of germ cell elements and, until recently, the absence of demonstrable amplification of 12p. We report a case that exhibited foci of yolk sac elements with papillary structures and intracytoplasmic periodic acid-Schiff-positive, diastase-resistant, ?-fetoprotein-positive, hyaline globules. An expanded area of undifferentiated cells, likely precursor cells, in the basal layer of the overlying mucosal epithelium transitions into and merges with the immature epithelial, neuroepithelial, and mesenchymal components. These previously unreported histomorphological features support the hypothesis that this tumor is a teratomatous tumor arising from pluripotent embryonic stem cells in the basal layer of the sinonasal epithelium. That notion is further supported by fluorescence in situ hybridization cytogenetic analysis, which showed a distinct subpopulation of the tumor cells with an extra copy of chromosome 12p13. PMID:20952296

Thomas, Jaiyeola; Adegboyega, Patrick; Iloabachie, Kenny; Mooring, John Wesley; Lian, Timothy

2011-04-01

162

A Specialized Outer Layer of the Primary Cell Wall Joins Elongating Cotton Fibers into Tissue-Like Bundles1[W][OA  

PubMed Central

Cotton (Gossypium hirsutum) provides the world's dominant renewable textile fiber, and cotton fiber is valued as a research model because of its extensive elongation and secondary wall thickening. Previously, it was assumed that fibers elongated as individual cells. In contrast, observation by cryo-field emission-scanning electron microscopy of cotton fibers developing in situ within the boll demonstrated that fibers elongate within tissue-like bundles. These bundles were entrained by twisting fiber tips and consolidated by adhesion of a cotton fiber middle lamella (CFML). The fiber bundles consolidated via the CFML ultimately formed a packet of fiber around each seed, which helps explain how thousands of cotton fibers achieve their great length within a confined space. The cell wall nature of the CFML was characterized using transmission electron microscopy, including polymer epitope labeling. Toward the end of elongation, up-regulation occurred in gene expression and enzyme activities related to cell wall hydrolysis, and targeted breakdown of the CFML restored fiber individuality. At the same time, losses occurred in certain cell wall polymer epitopes (as revealed by comprehensive microarray polymer profiling) and sugars within noncellulosic matrix components (as revealed by gas chromatography-mass spectrometry analysis of derivatized neutral and acidic glycosyl residues). Broadly, these data show that adhesion modulated by an outer layer of the primary wall can coordinate the extensive growth of a large group of cells and illustrate dynamic changes in primary wall structure and composition occurring during the differentiation of one cell type that spends only part of its life as a tissue. PMID:19369592

Singh, Bir; Avci, Utku; Eichler Inwood, Sarah E.; Grimson, Mark J.; Landgraf, Jeff; Mohnen, Debra; Sørensen, Iben; Wilkerson, Curtis G.; Willats, William G.T.; Haigler, Candace H.

2009-01-01

163

SALL4 expression in germ cell and non-germ cell tumors: a systematic immunohistochemical study of 3215 cases.  

PubMed

The SALL4 transcription factor is associated with embryonic cell pluripotency and has been shown as a useful immunohistochemical marker for germ cell tumors. However, information of SALL4 distribution in normal human tissues and non-germ cell tumors is limited. In this study we examined normal human tissues and 3215 tumors for SALL4 expression using a monoclonal antibody 6E3 and automated immunohistochemistry. In a 10-week embryo, SALL4 was expressed in ovocytes, intestine, kidney, and some hepatocytes. In adult tissues, it was only detected in germ cells. SALL4 was consistently expressed in all germ cell tumors except some trophoblastic tumors and mature components of teratomas, in which it was selectively expressed in intestinal-like and some squamous epithelia. In non-germ cell carcinomas, SALL4 was detected in 20% of cases or more of serous carcinoma of the ovary, urothelial high-grade carcinoma, and gastric adenocarcinoma (especially the intestinal type). SALL4 was only rarely (? 5%) expressed in mammary, colorectal, prostatic, and squamous cell carcinomas. Many SALL4-positive carcinomas showed poorly differentiated patterns, and some showed positivity in most tumor cells mimicking the expression in germ cell tumors. SALL4 was commonly expressed in rhabdoid tumors of the kidney and extrarenal sites and in the Wilms tumor. Expression of SALL4 was rare in other mesenchymal and neuroendocrine tumors but was occasionally detected in melanoma, desmoplastic small round cell tumor, epithelioid sarcoma, and rhabdomyosarcoma. All hematopoietic tumors were negative. SALL4 is an excellent marker of nonteratomatous germ cell tumors, but it is also expressed in other tumors, sometimes extensively. Such expression may reflect stem cell-like differentiation and must be considered when using SALL4 as a marker for germ cell tumors. Observed lack of other pluripotency factors, OCT4 and NANOG, in SALL4-positive non-germ cell tumors can also be diagnostically helpful. PMID:24525512

Miettinen, Markku; Wang, Zengfeng; McCue, Peter A; Sarlomo-Rikala, Maarit; Rys, Janusz; Biernat, Wojciech; Lasota, Jerzy; Lee, Yi-Shan

2014-03-01

164

E. Coli Germs Found on Farmers Market Herbs  

MedlinePLUS

... sharing features on this page, please enable JavaScript. E. Coli Germs Found on Farmers Market Herbs Nearly ... Preidt Friday, December 19, 2014 Related MedlinePlus Pages E. Coli Infections Food Safety FRIDAY, Dec. 19, 2014 ( ...

165

Female germ cell loss from radiation and chemical exposures.  

PubMed

Female germ cells in some mammals are extremely sensitive to killing by ionizing radiation, especially during development. Primordial oocytes in juvenile mice have an LD50 of only 6-7 rad, and the germ cell pool in squirrel monkeys is destroyed by prenatal exposure of 0.7 rad/day. Sensitivity varies greatly with species and germ cell stage. Unusually high sensitivity has not been found in macaques and may not occur in man, but this has not been established for all developmental stages. The exquisite oocyte radiosensitivity in mice apparently reflects vulnerability of the plasma membrane, not DNA, which may have implications for estimating human genetic risks. Germ cells can be killed also by chemicals. Such oocyte loss, with similarities to radiation effects, is under increasing study, including chemotherapy observations in women. More than 75 compounds have been tested in mice, with in vivo toxicity quantified by oocyte loss; certain chemicals apparently act on the membrane. PMID:6340477

Dobson, R L; Felton, J S

1983-01-01

166

General Information About Childhood Central Nervous System Germ Cell Tumors  

MedlinePLUS

... before the cancer is diagnosed and continue for months or years. Childhood CNS germ cell tumors may ... after treatment. Some cancer treatments cause side effects months or years after treatment has ended. Some cancer ...

167

Developmental transitions of germ cell lineage of the mouse  

E-print Network

Mammalian germ cells arise during early embryogenesis and migrate to the developing gonad where, under the direction of the somatic environment, they initiate distinct sex-specific developmental programs resulting in the ...

Baltus, Andrew Edmund

2006-01-01

168

Tritium effects on germ cells and fertility  

SciTech Connect

Primordial oocytes in juvenile mice show acute gamma-ray LD/sub 50/ as low as 6 rad. This provides opportunities for determining dose-response relations at low doses and chronic exposure in the intact animal - conditions of particular interest for hazard evaluation. Examined in this way, /sup 3/HOH in body water is found to kill murine oocytes exponentially with dose, the LD/sub 50/ level for chronic exposure being only 2..mu..Ci/ml (delivering 0.4 rad/day). At very low doses and dose rates, where comparisons between tritium and other radiations are of special significance for radiological protection, the RBE of tritium compared with /sup 60/Co gamma radiation reaches approximately 3. Effects on murine fertility from tritium-induced oocyte loss have been quantified by reproductive capacity measurements. Chronic low-level exposure has been examined also in three primate species - squirrel, rhesus, and bonnet monkeys. In squirrel monkeys the ovarian germ-cell supply is 99% destroyed by the time of birth from prenatal exposure to body-water levels of /sup 3/HOH (administered in maternal drinking water) of only 3 ..mu..Ci/ml, the LD/sub 50/ level being 0.5 ..mu..Ci/ml (giving 0.1 rad/day), one fourth that in mice. Though not completely ruled out, similar high sensitivity of female germ cells has not been found in macaques; and it probably does not occur in man. The exquisite radiosensitivity of primordial oocytes in mice is apparently due to vulnerability of the plasma membrane (or something of similar geometry and location), not DNA. Evidence for this comes from tritium data as well as neutron studies. Tritium administered as /sup 3/HOH, and therefore generally distributed, is much more effective in killing murine oocytes than is tritium administered as /sup 3/H-TdR, localized in the nucleus. This situation in the mouse may have implications for estimating radiation genetic risk in the human female.

Dobson, R.L.; Kwan, T.C.; Straume, T.

1982-11-19

169

Expression and function of protein phosphatase PP2A in malignant testicular germ cell tumours.  

PubMed

Testicular germ cell tumours (TGCT) represent the most common malignancy in young males. We reported previously that two prototype members of the mitogen-activated protein kinase (MAPK) family, the MAPK ERK kinase (MEK) and extracellular signal-regulated kinase (ERK), are inactive in malignant testicular germ cells and become active after drug stimulation, leading to apoptosis of tumour cells. In this study, we asked whether the protein phosphatase PP2A, a known inhibitor of the MEK-ERK pathway, participates in the proliferation and/or apoptosis of primary TGCT (n = 48) as well as two TGCT cell lines (NTERA and NCCIT). Quantitative RT-PCR, immunohistochemistry, western blot analyses and phosphatase assay indicate that primary TGCT as well as TGCT cell lines express PP2A and that PP2A is active in TGCT cell lines. The inhibition of PP2A by application of two PP2A inhibitors, cantharidic acid (CA) and okadaic acid (OA), results in a significant increase in caspase-3-mediated apoptosis of TGCT cell lines. Thereby, PP2A inhibition was accompanied by phosphorylation and activation of MEK and ERK. Functional assays using the MEK inhibitor PD98059 demonstrated that the phosphorylation of MEK and ERK was required for the induction of caspase-3-mediated apoptosis of malignant germ cells. Thus, our data suggest that inhibition of PP2A mediates its apoptosis-inducing effect on TGCT through activation of the MEK-ERK signalling pathway that leads to caspase-3-mediated apoptosis of tumour cells. In addition our results support previous observations that PP2A exerts an anti-apoptotic effect on malignant tumour cells. PMID:17590861

Schweyer, S; Bachem, A; Bremmer, F; Steinfelder, H J; Soruri, A; Wagner, W; Pottek, T; Thelen, P; Hopker, W W; Radzun, H J; Fayyazi, A

2007-09-01

170

Perspectives of germ cell development in vitro in mammals  

PubMed Central

Pluripotent stem cells, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are able to differentiate into all cell lineages of the embryo proper, including germ cells. This pluripotent property has a huge impact on the fields of regenerative medicine, developmental biology and reproductive engineering. Establishing the germ cell lineage from ESCs/iPSCs is the key biological subject, since it would contribute not only to dissection of the biological processes of germ cell development but also to production of unlimited numbers of functional gametes in vitro. Toward this goal, we recently established a culture system that induces functional mouse primordial germ cells (PGCs), precursors of all germ cells, from mouse ESCs/iPSCs. The successful in vitro production of PGCs arose from the study of pluripotent cell state, the signals inducing PGCs and the technology of transplantation. However, there are many obstacles to be overcome for the robust generation of mature gametes or for application of the culture system to other species, including humans and livestock. In this review, we discuss the requirements for a culture system to generate the germ cell lineage from ESCs/iPSCs. PMID:24725251

Hayashi, Katsuhiko; Saitou, Mitinori

2014-01-01

171

Effects of wheat germ agglutinin on membrane transport.  

PubMed

(1) Low concentrations of wheat germ agglutinin are cytotoxic toward several tissue culture lines, including Chinese hamster ovary cells, Swiss 3T3 cells, mouse L cells and baby hamster kidney cells. The LD50 ranged from 1 to 5 microgram wheat germ agglutinin per ml. Similar concentrations of the lectin inhibited the transport of the non-utilizable amino acids alpha-aminoisobutyric acid and cycloleucine and inhibited the uptake of thymidine. In contrast, 2-deoxy-D-glucose uptake was not altered and colchicine uptake was enhanced. (2) The inhibition of alpha-aminoisobutyric acid uptake occurred within minutes after lectin addition and was maximal by 1 h. Maximal inhibition ranged from 50 to 70% of control values. Studies of the kinetics of the uptake demonstrated that wheat germ agglutinin decreased the V of the uptake by 70% without affecting the apparent Km. Ovomucoid, a haptene inhibitor of wheat germ agglutinin-binding to cell surface receptors, prevented the wheat germ agglutinin-induced inhibition of alpha-aminoisobutyric acid transport. Three other lectins (Concanavalin A, Phaseolus vulgaris E-phytohemagglutinin and L-phytohemagglutinin) inhibited the uptake by 20% or less at doses up to 50 microgram/ml. (3) We propose that the cytotoxicity of wheat germ agglutinin probably results in part, if not totally, from membrane alterations which impair multiple membrane transport systems. PMID:561616

Li, E; Kronfeld, S

1977-09-01

172

Preconception exposures to potential germ-cell mutagens.  

PubMed

Radiation and other agents can cause germ-cell mutations in animal systems. No human germ-cell mutagen has been identified, but this does not mean that human germ-cells are not vulnerable to mutagenesis. There has been particular concern about the possible health effects on offspring following parental preconception exposure to ionizing radiation-both occupational and therapeutic. A strong association with preconception radiation exposure in the fathers of the cases was found in a case-control study of young people with leukaemia living near the Sellafield nuclear plant in the UK. Subsequent studies of workers occupationally exposed to ionizing radiation have failed to confirm these findings. No statistically significant effects have been reported from studies of possible indicators of germ-cell mutagenesis in the A-bomb survivors. Studies of offspring of cancer survivors who receive radiotherapy and mutagenic chemotherapy have found no evidence of germ-cell mutagenesis. Failure to detect human germ-cell mutagenic agents may be a consequence of inadequate study sizes or insufficiently sensitive laboratory techniques. PMID:18977774

Draper, Gerald

2008-01-01

173

A Mechanism of Male Germ Cell Apoptosis Induced by Bisphenol-A and Nonylphenol Involving ADAM17 and p38 MAPK Activation  

PubMed Central

Germ cell apoptosis regulation is pivotal in order to maintain proper daily sperm production. Several reports have shown that endocrine disruptors such as Bisphenol-A (BPA) and Nonylphenol (NP) induce germ cell apoptosis along with a decrease in sperm production. Given their ubiquitous distribution in plastic products used by humans it is important to clarify their mechanism of action. TACE/ADAM17 is a widely distributed extracellular metalloprotease and participates in the physiological apoptosis of germ cells during spermatogenesis. The aims of this work were: 1) to determine whether BPA and NP induce ADAM17 activation; and 2) to study whether ADAM17 and/or ADAM10 are involved in germ cell apoptosis induced by BPA and NP in the pubertal rat testis. A single dose of BPA or NP (50 mg/kg) induces germ cell apoptosis in 21-day-old male rats, which was prevented by a pharmacological inhibitor of ADAM17, but not by an inhibitor of ADAM10. In vitro, we showed that BPA and NP, at similar concentrations to those found in human samples, induce the shedding of exogenous and endogenous (TNF-?) ADAM17 substrates in primary rat Sertoli cell cultures and TM4 cell line. In addition, pharmacological inhibitors of metalloproteases and genetic silencing of ADAM17 prevent the shedding induced in vitro by BPA and NP. Finally, we showed that in vivo BPA and NP induced early activation (phosphorylation) of p38 MAPK and translocation of ADAM17 to the cell surface. Interestingly, the inhibition of p38 MAPK prevents germ cell apoptosis and translocation of ADAM17 to the cell surface. These results show for the first time that xenoestrogens can induce activation of ADAM17 at concentrations similar to those found in human samples, suggesting a mechanism by which they could imbalance para/juxtacrine cell-to-cell-communication and induce germ cell apoptosis. PMID:25474107

Moreno, Ricardo D.

2014-01-01

174

DEADSouth protein localizes to germ plasm and is required for the development of primordial germ cells in Xenopus laevis  

PubMed Central

Summary DEADSouth mRNA is a component of germ plasm in Xenopus laevis and encodes a DDX25 DEAD-box RNA helicase. To determine the intracellular localization of DEADSouth protein, we injected mRNA encoding DEADSouth tagged with mCherry fluorescent protein into fertilized eggs from transgenic Xenopus expressing EGFP fused with a mitochondrial targeting signal. The DEADSouth-mCherry fusion protein was localized to the germ plasm, a mitochondria-rich region in primordial germ cells (PGCs). DEADSouth overexpression resulted in a reduction of PGC numbers after stage 20. Conversely, DEADSouth knockdown using an antisense locked nucleic acid gapmer inhibited movement of the germ plasm from the cortex to the perinuclear region, resulting in inhibition of PGC division at stage 12 and a decrease in PGC numbers at later stages. The knockdown phenotype was rescued by intact DEADSouth mRNA, but not mutant mRNA encoding inactive DEADSouth helicase. Surprisingly, it was also rescued by mouse vasa homolog and Xenopus vasa-like gene 1 mRNAs that encode DDX4 RNA helicases. The rescue was dependent on the 3? untranslated region (3?UTR) of DEADSouth mRNA, which was used for PGC-specific expression. The 3?UTR contributed to localization of the injected mRNA to the germ plasm, resulting in effective localization of DEADSouth protein. These results demonstrate that localization of DEADSouth helicase to the germ plasm is required for proper PGC development in Xenopus laevis. PMID:23429978

Yamaguchi, Takeshi; Taguchi, Ayaka; Watanabe, Kenji; Orii, Hidefumi

2013-01-01

175

On the fate of primordial germ cells injected into early mouse embryos?  

PubMed Central

Primordial germ cells (PGCs) are the founder cells of the germline. Via gametogenesis and fertilisation this lineage generates a new embryo in the next generation. PGCs are also the cell of origin of multilineage teratocarcinomas. In vitro, mouse PGCs can give rise to embryonic germ (EG) cells – pluripotent stem cells that can contribute to primary chimaeras when introduced into pre-implantation embryos. Thus, PGCs can give rise to pluripotent cells in the course of the developmental cycle, during teratocarcinogenesis and by in vitro culture. However, there is no evidence that PGCs can differentiate directly into somatic cell types. Furthermore, it is generally assumed that PGCs do not contribute to chimaeras following injection into the early mouse embryo. However, these data have never been formally published. Here, we present the primary data from the original PGC-injection experiments performed 40 years ago, alongside results from more recent studies in three separate laboratories. These results have informed and influenced current models of the relationship between pluripotency and the germline cycle. Current technologies allow further experiments to confirm and expand upon these findings and allow definitive conclusions as to the developmental potency of PGCs. PMID:24269765

Leitch, Harry G.; Okamura, Daiji; Durcova-Hills, Gabriela; Stewart, Colin L.; Gardner, Richard L.; Matsui, Yasuhisa; Papaioannou, Virginia E.

2014-01-01

176

Xpat, a gene expressed specifically in germ plasm and primordial germ cells of Xenopus laevis.  

PubMed

cDNAs specific to vegetal poles of Xenopus gastrula embryos were used as a probe to screen a gastrula vegetal pole cDNA library. One of the novel clones isolated had an RNA expression pattern consistent with it being a component of germ plasm and it was thus named Xpat (Xenopus primordial germ cell associated transcript). The open reading frame encodes a 35 kDa protein with no clear homologies. The RNA is localised to the vegetal pole throughout oogenesis and early cleavage. During gastrulation cells containing this message move internally and at tailbud stages they migrate in an antero-dorsal direction. Xpat mRNA is not detectable once the dorsal mesentery forms. We show that the 3'-UTR is required and is sufficient for localisation of exogenous RNA to the vegetal pole of oocytes. We propose that Xpat UTR-containing transcripts can be localised by the Vg1 or late pathway of mRNA localisation during stage III of oogenesis, but endogenous Xpat appears to be localised earlier by a mitochondrial cloud mechanism similar to that proposed for Xcat-2. PMID:9622619

Hudson, C; Woodland, H R

1998-05-01

177

Apparent diffusion coefficient of intracranial germ cell tumors.  

PubMed

The role of diffusion weighted imaging and apparent diffusion coefficient in intracranial germ cell tumors has not been fully elucidated. The aim of this study was to evaluate whether the ADC correlates with the histologic subtypes of germ cell tumors. We also aimed to investigate whether the ADC values can predict treatment response. The authors retrospectively analyzed the ADC values of the enhancing and solid regions of germ cell tumors. The absolute ADC values and the normalized ADC values were compared among different histologic diagnoses. The ADC values before and after the first course of chemotherapy were also compared between the different prognostic groups. Ten patients were included in the study. The median age at diagnosis was 9.3 years (range 5.3-13.8 years). There were four patients with germinoma and six patients with nongerminomatous germ cell tumor (NGGCT) including five mixed germ cell tumors and one immature teratoma. The mean absolute and normalized ADC values (×10(-3) mm(2)/s) were significantly lower in germinomas [0.835 ± 0.065 (standard deviation) and 1.11 ± 0.096, respectively] than in NGGCTs (1.271 ± 0.145 and 1.703 ± 0.223, respectively) (p = 0.01). The ADC values before and after the first course of chemotherapy were available in four patients. The ADC value after the first chemotherapy had a tendency to increase more in patients who eventually demonstrated complete response with chemotherapy than in patients who required second-look surgery. Assessment of the ADC values of germ cell tumors is considered to facilitate differentiation of histological subtypes of germ cell tumors. Evaluation of the ADC may also be useful for predicting treatment response. PMID:25413617

Ogiwara, Hideki; Tsutsumi, Yoshiyuki; Matsuoka, Kentarou; Kiyotani, Chikako; Terashima, Keita; Morota, Nobuhito

2014-11-21

178

Introduction to Germ Cell Development in C. elegans  

PubMed Central

A central feature of the continuum of life in sexually reproducing metazoans is the cycle of the germline from one generation to the next. This volume describes the cycle of the germline for Caenorhabditis elegans, through chapters that are focused on distinct aspects or processes in germ cell development. Topics include sequential and dependent processes such as specification of germ cells as distinct from somatic cells, sex determination, stem cell proliferative fate versus meiotic development decision, recombination/ progression through meiotic prophase, contemporaneous processes such as gametogenesis, meiotic development and apoptosis, and continuing the cycle into the next generation through fertilization and the oocyte-to-embryo-transition. Throughout germ cell development, translational control and epigenetic mechanisms play prominent roles. These different aspects of germ cell development are seamlessly integrated under optimal conditions and are modified in the different reproductive strategies that are employed by C. elegans under harsh environmental conditions. In this chapter we set the stage by providing a brief background on the C. elegans system and germ cell development, indicating processes in the cycle of the germline that are covered in each chapter. PMID:22872472

Pazdernik, Nanette; Schedl, Tim

2013-01-01

179

Expression of Arf Tumor Suppressor in Spermatogonia Facilitates Meiotic Progression in Male Germ Cells  

PubMed Central

The mammalian Cdkn2a (Ink4a-Arf) locus encodes two tumor suppressor proteins (p16Ink4a and p19Arf) that respectively enforce the anti-proliferative functions of the retinoblastoma protein (Rb) and the p53 transcription factor in response to oncogenic stress. Although p19Arf is not normally detected in tissues of young adult mice, a notable exception occurs in the male germ line, where Arf is expressed in spermatogonia, but not in meiotic spermatocytes arising from them. Unlike other contexts in which the induction of Arf potently inhibits cell proliferation, expression of p19Arf in spermatogonia does not interfere with mitotic cell division. Instead, inactivation of Arf triggers germ cell–autonomous, p53-dependent apoptosis of primary spermatocytes in late meiotic prophase, resulting in reduced sperm production. Arf deficiency also causes premature, elevated, and persistent accumulation of the phosphorylated histone variant H2AX, reduces numbers of chromosome-associated complexes of Rad51 and Dmc1 recombinases during meiotic prophase, and yields incompletely synapsed autosomes during pachynema. Inactivation of Ink4a increases the fraction of spermatogonia in S-phase and restores sperm numbers in Ink4a-Arf doubly deficient mice but does not abrogate ?-H2AX accumulation in spermatocytes or p53-dependent apoptosis resulting from Arf inactivation. Thus, as opposed to its canonical role as a tumor suppressor in inducing p53-dependent senescence or apoptosis, Arf expression in spermatogonia instead initiates a salutary feed-forward program that prevents p53-dependent apoptosis, contributing to the survival of meiotic male germ cells. PMID:21811412

Churchman, Michelle L.; Roig, Ignasi; Jasin, Maria; Keeney, Scott; Sherr, Charles J.

2011-01-01

180

Functional Analysis of the Drosophila Embryonic Germ Cell Transcriptome by RNA Interference  

PubMed Central

In Drosophila melanogaster, primordial germ cells are specified at the posterior pole of the very early embryo. This process is regulated by the posterior localized germ plasm that contains a large number of RNAs of maternal origin. Transcription in the primordial germ cells is actively down-regulated until germ cell fate is established. Bulk expression of the zygotic genes commences concomitantly with the degradation of the maternal transcripts. Thus, during embryogenesis, maternally provided and zygotically transcribed mRNAs determine germ cell development collectively. In an effort to identify novel genes involved in the regulation of germ cell behavior, we carried out a large-scale RNAi screen targeting both maternal and zygotic components of the embryonic germ line transcriptome. We identified 48 genes necessary for distinct stages in germ cell development. We found pebble and fascetto to be essential for germ cell migration and germ cell division, respectively. Our data uncover a previously unanticipated role of mei-P26 in maintenance of embryonic germ cell fate. We also performed systematic co-RNAi experiments, through which we found a low rate of functional redundancy among homologous gene pairs. As our data indicate a high degree of evolutionary conservation in genetic regulation of germ cell development, they are likely to provide valuable insights into the biology of the germ line in general. PMID:24896584

Bujna, Ágnes; Vilmos, Péter; Spirohn, Kerstin; Boutros, Michael; Erdélyi, Miklós

2014-01-01

181

Primary human chorionic gonadotropin secreting germinoma of the corpus callosum  

PubMed Central

Background: Primary intracranial germinomas are a rare subset of intracranial tumors derived from mis-incorporated germ cells within the folding neural plate during embryogenesis. Though known to arise from midline structures in the central nervous system (CNS), occurrence within the corpus callosum is exceedingly rare. Case Description: We present a rare case of secreting primary intracranial germinoma with extensive intraventricular metastasis presenting as a multi-cystic butterfly lesion in the genu of the corpus callosum in a young boy. Conclusion: Intracranial germ cell tumors must be considered for any multi-cystic lesion arising from midline structures in the CNS in the preadult population. PMID:24233184

Chuan Aaron, Foo Song; Dawn, Chong Q. Q.; Kenneth, Chang T. E.; Hoe, Ng Wai; Yen, Soh Shui; Chee Kian, Tham

2013-01-01

182

Reproduction of wild birds via interspecies germ cell transplantation.  

PubMed

The present study was conducted to apply an interspecies germ cell transfer technique to wild bird reproduction. Pheasant (Phasianus colchicus) primordial germ cells (PGCs) retrieved from the gonads of 7-day-old embryos were transferred to the bloodstream of 2.5-day-old chicken (Gallus gallus) embryos. Pheasant-to-chicken germline chimeras hatched from the recipient embryos, and 10 pheasants were derived from testcross reproduction of the male chimeras with female pheasants. Gonadal migration of the transferred PGCs, their involvement in spermatogenesis, and production of chimeric semen were confirmed. The phenotype of pheasant progenies derived from the interspecies transfer was identical to that of wild pheasants. The average efficiency of reproduction estimated from the percentage of pheasants to total progenies was 17.5%. In conclusion, interspecies germ cell transfer into a developing embryo can be used for wild bird reproduction, and this reproductive technology may be applicable in conserving endangered bird species. PMID:18685127

Kang, Seok Jin; Choi, Jin Won; Kim, Sun Young; Park, Kyung Je; Kim, Tae Min; Lee, Young Mok; Kim, Heebal; Lim, Jeong Mook; Han, Jae Yong

2008-11-01

183

Chiral discotic columnar germs of nucleosome core particles.  

PubMed Central

In concentrated solution and in the presence of high concentrations of monovalent cations, nucleosome core particles order into a discotic columnar mesophase. This phase is limited to finite-sized hexagonal germs that further divide into six coiled branches, following an iterative process. We show how the structure of the germs comes from the competition between hexagonal packing and chirality with a combination of dendritic facetting and double-twist configurations. Geometrical considerations lead us to suspect that the chirality of the eukaryotic chromosomes may originate from the same competition. PMID:10777768

Livolant, F; Leforestier, A

2000-01-01

184

Fetal germ cell differentiation and the impact of the somatic cells   

E-print Network

Specification of a germ cell lineage and appropriate maturation are essential for the transfer of genetic information from one generation to the next. Germ cells form from pluripotent precursor cells that migrate into ...

Cowan, Gillian

2009-01-01

185

Germ cell tumours in uncorrected cryptorchid testis at Institute Rotary Cancer Hospital, New Delhi.  

PubMed Central

Twenty-four out of 164 (14%) adult patients with primary germ cell tumours of testis seen over the last 6 years at the Institute Rotary Cancer Hospital (IRCH) of the All India Institute of Medical Sciences (AIIMS), New Delhi, were found to have cryptorchidism. Only one patient had undergone correction. As a result the testes were intra-abdominal in the vast majority, and patients presented late. Twenty-two patients presented with stage IIb or more advanced disease. Twelve patients had seminoma and the others had mixed or non-seminomatous germ cell tumour (NSGCT), i.e. 50% each. The earlier patients were managed by initial resection followed by radiation and/or chemotherapy. As experience grew the seven patients who presented late were given initial chemotherapy followed by resection in those with residual tumours. The probability of overall survival was 0.65 at 36 months and, was not significantly different from survival in 114 patients with tumours of normally descended testis. Early orchipexy facilitates the detection, but whether it reduces the incidence of tumours is controversial. Uncorrected cryptorchidism is now rarely seen in the West, but in India and many other developing countries tumours of uncorrected cryptorchid testes continue to be seen. PMID:7841056

Raina, V.; Shukla, N. K.; Gupta, N. P.; Deo, S.; Rath, G. K.

1995-01-01

186

Presence of Mitochondrial Large Ribosomal RNA Outside Mitochondria in Germ Plasm of Drosophila melanogaster  

Microsoft Academic Search

Mitochondrial large ribosomal RNA (mtlrRNA) has been identified as a cytoplasmic factor that induces pole cell formation in embryos whose ability to form a germ line has been abolished by treatment with ultraviolet light. In situ hybridization analyses reveal that mtlrRNA is enriched in germ plasm and is tightly associated with polar granules, the distinctive organelles of germ plasm, which

Satoru Kobayashi; Reiko Amikura; Masukichi Okada

1993-01-01

187

Evidence against a germ plasm in the milkweed bug Oncopeltus fasciatus, a hemimetabolous insect.  

PubMed

Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic nuclei that inherit this "germ plasm" acquire PGC fate. In contrast, historical studies of basally branching insects (Hemimetabola) suggest that a maternal requirement for germ line genes in PGC specification may be a derived character confined principally to Holometabola. However, there have been remarkably few investigations of germ line gene expression and function in hemimetabolous insects. Here we characterise PGC formation in the milkweed bug Oncopeltus fasciatus, a member of the sister group to Holometabola, thus providing an important evolutionary comparison to members of this clade. We examine the transcript distribution of orthologues of 19 Drosophila germ cell and/or germ plasm marker genes, and show that none of them localise asymmetrically within Oncopeltus oocytes or early embryos. Using multiple molecular and cytological criteria, we provide evidence that PGCs form after cellularisation at the site of gastrulation. Functional studies of vasa and tudor reveal that these genes are not required for germ cell formation, but that vasa is required in adult males for spermatogenesis. Taken together, our results provide evidence that Oncopeltus germ cells may form in the absence of germ plasm, consistent with the hypothesis that germ plasm is a derived strategy of germ cell specification in insects. PMID:23789106

Ewen-Campen, Ben; Jones, Tamsin E M; Extavour, Cassandra G

2013-06-15

188

Evidence against a germ plasm in the milkweed bug Oncopeltus fasciatus, a hemimetabolous insect  

PubMed Central

Summary Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic nuclei that inherit this “germ plasm” acquire PGC fate. In contrast, historical studies of basally branching insects (Hemimetabola) suggest that a maternal requirement for germ line genes in PGC specification may be a derived character confined principally to Holometabola. However, there have been remarkably few investigations of germ line gene expression and function in hemimetabolous insects. Here we characterise PGC formation in the milkweed bug Oncopeltus fasciatus, a member of the sister group to Holometabola, thus providing an important evolutionary comparison to members of this clade. We examine the transcript distribution of orthologues of 19 Drosophila germ cell and/or germ plasm marker genes, and show that none of them localise asymmetrically within Oncopeltus oocytes or early embryos. Using multiple molecular and cytological criteria, we provide evidence that PGCs form after cellularisation at the site of gastrulation. Functional studies of vasa and tudor reveal that these genes are not required for germ cell formation, but that vasa is required in adult males for spermatogenesis. Taken together, our results provide evidence that Oncopeltus germ cells may form in the absence of germ plasm, consistent with the hypothesis that germ plasm is a derived strategy of germ cell specification in insects. PMID:23789106

Ewen-Campen, Ben; Jones, Tamsin E. M.; Extavour, Cassandra G.

2013-01-01

189

Effect of oil extraction method on the enzymatic digestibility of corn germ arabinoxylan  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole corn germ and germs extracted by three different processes were all excellent substrates for arabinoxylan digestion by crude enzymes from Aureobasidium strain NRRL Y-2311-1. Thus, oil extraction does not serve as a pretreatment to enhance digestibility. Fully expelled germ was slightly more ...

190

A zebrafish homologue of the chemokine receptor Cxcr4 is a germ-cell guidance receptor  

Microsoft Academic Search

Germ cells preserve an individual's genetic information and transmit it to the next generation. Early in development germ cells are set aside and undergo a specialized developmental programme, a hallmark of which is the migration from their site of origin to the future gonad. In Drosophila, several factors have been identified that control germ-cell migration to their target tissues; however,

Holger Knaut; Christian Werz; Robert Geisler; Christiane Nüsslein-Volhard

2003-01-01

191

The meiosis inducing interaction between germ cells and rete cells in the fetal mouse gonad  

E-print Network

The meiosis inducing interaction between germ cells and rete cells in the fetal mouse gonad Anne., Denmark. Introduction. In the mammalian gonad the onset of meiosis of the female germ cells occurs much earlier in life than meiosis of the male germ cells. In the ovary we know that both the differentiation

Paris-Sud XI, Université de

192

GAGE Cancer-Germline Antigens Are Recruited to the Nuclear Envelope by Germ Cell-Less (GCL)  

PubMed Central

GAGE proteins are highly similar, primate-specific molecules with unique primary structure and undefined cellular roles. They are restricted to cells of the germ line in adult healthy individuals, but are broadly expressed in a wide range of cancers. In a yeast two-hybrid screen we identified the metazoan transcriptional regulator, Germ cell-less (GCL), as an interaction partner of GAGE12I. GCL directly binds LEM-domain proteins (LAP2?, emerin, MAN1) at the nuclear envelope, and we found that GAGE proteins were recruited to the nuclear envelope inner membrane by GCL. Based on yeast two-hybrid analysis and pull-down experiments of GCL polypeptides, GCL residues 209–320 (which includes the BACK domain) were deduced sufficient for association with GAGE proteins. GAGE mRNAs and GCL mRNA were demonstrated in human testis and most types of cancers, and at the protein level GAGE members and GCL were co-expressed in cancer cell lines. Structural studies of GAGE proteins revealed no distinct secondary or tertiary structure, suggesting they are intrinsically disordered. Interestingly GAGE proteins formed stable complexes with dsDNA in vitro at physiological concentrations, and GAGE12I bound several different dsDNA fragments, suggesting sequence-nonspecific binding. Dual association of GAGE family members with GCL at the nuclear envelope inner membrane in cells, and with dsDNA in vitro, implicate GAGE proteins in chromatin regulation in germ cells and cancer cells. PMID:23029259

Gjerstorff, Morten F.; Rösner, Heike I.; Pedersen, Christina B.; Greve, Katrine B. V.; Schmidt, Steffen; Wilson, Katherine L.; Mollenhauer, Jan; Besir, Hüseyin; Møllegaard, Niels Erik; Ditzel, Henrik J.

2012-01-01

193

Everyday Preventive Actions That Can Help Fight Germs, Like Flu  

E-print Network

Everyday Preventive Actions That Can Help Fight Germs, Like Flu CDC recommends a three-step approach to fighting the flu. CDC recommends a three-step approach to fighting influenza (flu). The first and most important step is to get a flu vaccination each year. But if you get the flu

Tipple, Brett

194

INTRODUCTION Germ cells are both pluripotent and immortal, because they  

E-print Network

the C. elegans life cycle, P granules that contain proteins and mRNA are present specifically in germline cells (Pitt et al., 2000; Schisa et al., 2001; Seydoux and Fire, 1994; Strome and Wood, 1982; Subramaniam and Seydoux, 1999). In Drosophila, polar granules that are similar to P granules specify germ cell

Blackwell, Keith

195

Tropics, Germs, and Crops: How Endowments Influence Economic Development  

Microsoft Academic Search

Does economic development depend on geographic endowments like temperate instead of tropical location, the ecological conditions shaping diseases, or an environment good for grains or certain cash crops? Or do these endowments of tropics, germs, and crops affect economic development only through institutions or policies? We test the endowment, institution, and policy views against each other using cross country evidence.

William Easterly; Ross E. Levine

2002-01-01

196

Tropics, germs, and crops: how endowments influence economic development  

Microsoft Academic Search

Does economic development depend on geographic endowments like temperate instead of tropical location, the ecological conditions shaping diseases, or an environment good for grains or certain cash crops? Or do these endowments of tropics, germs, and crops affect economic development only through institutions or policies? We test the endowment, institution, and policy views against each other using cross country evidence.

William Easterly; Ross Levine

2003-01-01

197

Mechanisms guiding primordial germ cell migration: strategies from different organisms  

Microsoft Academic Search

The regulated migration of cells is essential for development and tissue homeostasis, and aberrant cell migration can lead to an impaired immune response and the progression of cancer. Primordial germ cells (PGCs), precursors to sperm and eggs, have to migrate across the embryo to reach somatic gonadal precursors, where they carry out their function. Studies of model organisms have revealed

Brian E. Richardson; Ruth Lehmann

2010-01-01

198

Composition and Molecular Weight Distribution of Carob Germ Proteins Fractions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biochemical properties of carob germ proteins were analyzed using a combination of selective extraction, reversed-phase high performance liquid chromatography (RP-HPLC), size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and electrophoretic analysis. Using a mo...

199

[Development of germ cells in chick ovarian medulla].  

PubMed

Ovaries from chick embryos and chicken have been investigated with a view to the evolution of germ cells in the medullary. They can enter meiosis and reach pachytene. They seem to be eliminated by the way of the lacunas. Some observations can be utilized in a discussion about the initiation of the meiosis and the evolution of the ovocytes. PMID:131621

Kopp, F; Stahl, A

1975-01-01

200

Urbisexuality: the evolution of bilaterian germ cell specification and reproductive  

E-print Network

information on the genetics and morphological processes that it used to construct its gut, heart, eyes will review the current and historical literature on germ-cell and somatic gonad anatomy, embryonic of its reproductive system anatomy or reproductive strategies; rather, I will suggest that these data can

Extavour, Cassandra

201

Transcriptional control of KIT gene expression during germ cell development.  

PubMed

The characterization of the mechanisms that regulate KIT expression in germ cells at different times of their development is important not only in the field of reproduction, but also for a better understanding of the biology of testicular germ cell tumors (TGCTs). Indeed this tyrosine kinase receptor, besides being essential for the survival and proliferation of primordial germ cells (PGCs) and for postnatal spermatogenesis and oogenesis, is also frequently overexpressed or constitutively active due to activating mutations in carcinoma in situ of the testis and in seminomas. In this review, I will summarize available data about the transcriptional mechanisms involved in the control of Kit expression in the germline. Variable mechanisms, involving different germ cell-specific transcription factors, are operating in the various developmental stages: SOX2 and SOHLH1/2 act as direct positive regulators in PGCs and in postnatal spermatogonia, respectively, whereas PLZF suppresses KIT expression in spermatogonial stem cells. DMRT1, acting through indirect mechanisms, suppresses KIT transcription in fetal gonocytes, while activating it in differentiating spermatogonia. PMID:23784828

Rossi, Pellegrino

2013-01-01

202

GERM-LINE SPECIFIC FACTORS IN CHEMICAL MUTAGENESIS  

EPA Science Inventory

Chemical mutagenesis test results ave not revealed evidence of germ-line specific mutagens. owever, conventional assays have indicated that there are male-female differences in mutagenic response, as well as quantitative/qualitative differences in induced mutations which depend u...

203

Fetal age estimation using MSCT scans of deciduous tooth germs.  

PubMed

Evaluation of fetal age is an essential element in many fields such as anthropology, odontology, paleopathology, and forensic sciences. This study examines the correlation between fetal age, femoral diaphyseal length (considered as the gold standard), and deciduous tooth germs of fetuses aged 22 to 40 weeks amenorrhea (WA) based on computed tomography (MSCT) reconstructions. Qualitative and quantitative studies of femoral and deciduous tooth germ lengths were performed on 81 fetuses (39 females and 42 males). R software was used for statistical analyses. Intra-observer and inter-observer variabilities and the interclass correlation coefficient (ICC) were calculated. Correlation coefficients (R (2)) and linear regression equations were calculated. Intra- and inter-observer variabilities were very satisfactory (intra-observer ICC???0.96, inter-observer ICC???0.95). Femoral length was significantly correlated with age (R (2)?=?0.9). The correlation coefficient between age and height, width, and dental volume was R (2)???0.73. Tooth germs were good indicators of fetal age. Our method appears to be reliable and reproducible, and the results of this study agreed with those of the literature. The dental formula provided a precise estimation of fetal age between 25 and 32 WA. Tooth germs were reliable indicators of fetal age, and multislice computed tomography was shown to be an innovative and reliable technology for this purpose. PMID:23828625

Minier, Marie; Maret, Delphine; Dedouit, Fabrice; Vergnault, Marion; Mokrane, Fathima-Zohra; Rousseau, Hervé; Adalian, Pascal; Telmon, Norbert; Rougé, Daniel

2014-01-01

204

Wheat germ lectin-Sepharose affinity adsorption assay for the soluble glucagon receptor  

SciTech Connect

An assay was developed based on the observation that many hormone receptors are glycoproteins. To test if the glucagon receptor is a glycoprotein, the receptor was used that had (/sup 125/I-Tyr/sup 10/)monoiodoglucagon covalently attached. The covalently labelled receptor was solubilized and exposed to wheat germ lectin-Sepharose in the presence and absence of various sugars. The sugar specificity for the adsorption of the glucagon receptor indicated that the receptor is a glycoprotein. The primary structure of glucagon is known and has been shown that it has no sugars attached to it. Therefore, the different in covalently attached sugars between the hormone and the receptor was used to develop an assay for the solubilized receptor. The hormone-receptor complex was specifically adsorbed onto the lectin-Sepharose while the free hormone remained in solution.

Iyengar, R.; Herberg, J.T.

1985-01-01

205

Anastomosis of germ tubes and nuclear migration of nuclei in germ tube networks of the soybean rust pathogen, Phakopsora pachyrhizi  

Technology Transfer Automated Retrieval System (TEKTRAN)

Parasexual recombination through hyphal anastomosis is an important mechanism for genetic diversity in filamentous fungi. In this study, we observed fusion of germ tubes in germinating urediniospores of Phakopsora pachyrhizi resulting in a complex hyphal network. Staining of the germinating uredinio...

206

The Fragilis interferon-inducible gene family of transmembrane proteins is associated with germ cell specification in mice  

Microsoft Academic Search

BACKGROUND: Specification of primordial germ cells in mice depends on instructive signalling events, which act first to confer germ cell competence on epiblast cells, and second, to impose a germ cell fate upon competent precursors. fragilis, an interferon-inducible gene coding for a transmembrane protein, is the first gene to be implicated in the acquisition of germ cell competence. RESULTS: Here,

M Saitou; SC Barton; MA Surani

2003-01-01

207

Somatic KIT mutations occur predominantly in seminoma germ cell tumors and are not predictive of bilateral disease: report of 220 tumors and review of literature.  

PubMed

Mutations in the KIT gene occur in approximately 8% of all testicular germ cell tumors (TGCT) and KIT is the most frequently mutated known cancer gene. One report has shown that 93% of patients with bilateral disease have a mutation at codon 816 of the KIT gene. Importantly, this suggests that the identification of a mutation in KIT is predictive of the development of a contralateral TGCT. We investigated the frequency and type of mutations in KIT in a series of 220 tumors from 211 patients with TGCTs and extragonadal germ cell tumors. In 170 patients with unilateral TGCT and no additional germ cell tumour, we identified one exon 11 mutation in a patient with unilateral TGCT and eight activating KIT mutations in exon 17 (9/175, 5.1%). In 32 patients with bilateral TGCT, one patient had an activating KIT mutation in exon 17 (3.1%). The incidence of activating KIT mutations in sporadic TGCT vs. familial TGCT was not significantly different. All mutations were identified in seminomas. Three extragonadal primary germ cell tumors were examined and in one tumor an activating KIT mutation was demonstrated in the pineal germinoma. Interestingly, this mutation was also seen in the patient's testicular seminoma. We find no evidence for an increased frequency of KIT mutations in bilateral TGCT. PMID:17943970

Coffey, Jerome; Linger, Rachel; Pugh, Julia; Dudakia, Darshna; Sokal, Michael; Easton, Douglas F; Timothy Bishop, D; Stratton, Michael; Huddart, Robert; Rapley, Elizabeth A

2008-01-01

208

Lifetime stress experience: transgenerational epigenetics and germ cell programming.  

PubMed

The transgenerational epigenetic programming involved in the passage of environmental exposures to stressful periods from one generation to the next has been examined in human populations, and mechanistically in animal models. Epidemiological studies suggest that gestational exposures to environmental factors including stress are strongly associated with an increased risk of neurodevelopmental disorders, including attention deficit-hyperactivity disorder, schizophrenia, and autism spectrum disorders. Both maternal and paternal life experiences with stress can be passed on to offspring directly during pregnancy or through epigenetic marks in the germ cell. Animal models of parental stress have examined relevant offspring phenotypes and transgenerational outcomes, and provided unique insight into the germ cell epigenetic changes associated with disruptions in neurodevelopment. Understanding germline susceptibility to exogenous signals during stress exposure and the identification of the types of epigenetic marks is critical for defining mechanisms underlying disease risk. PMID:25364281

Bale, Tracy L

2014-09-01

209

In Search of a Germ Theory Equivalent for Chronic Disease  

PubMed Central

The fight against infectious disease advanced dramatically with the consolidation of the germ theory in the 19th century. This focus on a predominant cause of infections (ie, microbial pathogens) ultimately led to medical and public health advances (eg, immunization, pasteurization, antibiotics). However, the resulting declines in infections in the 20th century were matched by a rise in chronic, noncommunicable diseases, for which there is no single underlying etiology. The discovery of a form of low-grade systemic and chronic inflammation (“metaflammation”), linked to inducers (broadly termed “anthropogens”) associated with modern man-made environments and lifestyles, suggests an underlying basis for chronic disease that could provide a 21st-century equivalent of the germ theory. PMID:22575080

2012-01-01

210

Lifetime stress experience: transgenerational epigenetics and germ cell programming  

PubMed Central

The transgenerational epigenetic programming involved in the passage of environmental exposures to stressful periods from one generation to the next has been examined in human populations, and mechanistically in animal models. Epidemiological studies suggest that gestational exposures to environmental factors including stress are strongly associated with an increased risk of neurodevelopmental disorders, including attention deficit-hyperactivity disorder, schizophrenia, and autism spectrum disorders. Both maternal and paternal life experiences with stress can be passed on to offspring directly during pregnancy or through epigenetic marks in the germ cell. Animal models of parental stress have examined relevant offspring phenotypes and transgenerational outcomes, and provided unique insight into the germ cell epigenetic changes associated with disruptions in neurodevelopment. Understanding germline susceptibility to exogenous signals during stress exposure and the identification of the types of epigenetic marks is critical for defining mechanisms underlying disease risk. PMID:25364281

Bale, Tracy L.

2014-01-01

211

Conservation of germ plasm from bison infected with Brucella abortus.  

PubMed

Reproductive procedures for cattle were adapted to American bison (Bison bison) to evaluate the potential preservation of germ plasm from bison infected with Brucella abortus without transmission of the pathogen to the recipient or offspring. Two of four experimentally inoculated bison bulls excreted B. abortus in the semen. Four healthy calves were produced from non-infected, un-vaccinated bison cows by natural breeding with a bison bull excreting B. abortus in the semen. There was no seroconversion of the cows or their calves. Two culture negative bison calves were produced by superovulation of infected bison donor cows followed by artificial insemination and embryo transfer without transmitting B. abortus to recipient cows or calves. These limited data indicate that embryo manipulatory procedures and natural breeding in bison may facilitate preservation of valuable germ plasm from infected bison while reducing the risk of transmission of B. abortus to recipients and progeny. PMID:9706568

Robison, C D; Davis, D S; Templeton, J W; Westhusin, M; Foxworth, W B; Gilsdorf, M J; Adams, L G

1998-07-01

212

Salvage high-dose chemotherapy for children with extragonadal germ-cell tumours  

PubMed Central

We reviewed the European Group for Blood and Marrow Transplantation (EBMT) experience with salvage high-dose chemotherapy (HDC) in paediatric patients with extragonadal germ-cell tumour (GCT). A total of 23 children with extragonadal GCT, median age 12 years (range 1–20), were treated with salvage HDC with haematopoietic progenitor cell support. The GCT primary location was intracranial site in nine cases, sacrococcyx in eight, retroperitoneum in four, and mediastinum in two. In all, 22 patients had a nongerminomatous GCT and one germinoma. Nine patients received HDC in first- and 14 in second- or third-relapse situation. No toxic deaths occurred. Overall, 16 of 23 patients (70%) achieved a complete remission. With a median follow-up of 66 months (range 31–173 months), 10 (43%) are continuously disease-free. Of six patients who had a disease recurrence after HDC, one achieved a disease-free status with surgical resection followed by chemotherapy and radiotherapy. In total, 11 patients (48%) are currently disease-free. Eight of 14 patients (57%) with extracranial primary and three of nine patients (33%) with intracranial primary GCT are currently disease-free. HDC induced impressive long-term remissions as salvage treatment in children with extragonadal extracranial GCTs. Salvage HDC should be investigated in prospective trials in these patients. PMID:16106248

De Giorgi, U; Rosti, G; Slavin, S; Yaniv, I; Harousseau, J L; Ladenstein, R; Demirer, T; Dini, G

2005-01-01

213

Prepubertal male rats with high rates of germ-cell apoptosis present exacerbated rates of germ-cell apoptosis after serotonin depletion.  

PubMed

Male germ-cell apoptosis occurs naturally and can be increased by exposure to drugs and toxic chemicals. Individuals may have different rates of apoptosis and are likely to also exhibit differential sensitivity to outside influences. Previously, we reported that p-chloroamphetamine (pCA), a substance that inhibits serotonin synthesis, induced germ-cell apoptosis in prepubertal male rats. Here, we identified prepubertal rats with naturally high or low rates of germ-cell apoptosis and evaluated gene expression in both groups. Bax and Shbg mRNA levels were higher in rats with high rates of germ-cell apoptosis. Rats were then treated with pCA and the neuro-hormonal response and gene expression were evaluated. Treatment with pCA induced a reduction in serotonin concentrations but levels of sex hormones and gonadotrophins were not changed. Rats with initially high rates of germ-cell apoptosis had even higher rates of germ-cell apoptosis after treatment with pCA. In rats with high rates of germ-cell apoptosis Bax mRNA expression remained high after treatment with pCA. On the basis of category, an inverse relationship between mRNA expression of Bax and Bcl2, Bax and AR and Bax and Hsd3b2 was found. Here we provide evidence that innate levels of germ-cell apoptosis could be explained by the level of mRNA expression of genes involved with apoptosis and spermatogenesis. PMID:25486044

Méndez Palacios, Néstor; Escobar, María Elena Ayala; Mendoza, Maximino Méndez; Crispín, Rubén Huerta; Andrade, Octavio Guerrero; Melández, Javier Hernández; Martínez, Andrés Aragón

2014-11-20

214

Intraperitoneal germ cell transplantation in the Nile tilapia Oreochromis niloticus.  

PubMed

Germ cell transplantation offers promising applications in finfish aquaculture and the preservation of endangered species. Here, we describe an intraperitoneal spermatogonia transplantation procedure in the Nile tilapia Oreochromis niloticus. Through histological analysis of early gonad development, we first determined the best suitable stage at which exogenous germ cells should be transplanted into the recipients. For the transplantation procedure, donor testes from a transgenic Nile tilapia strain carrying the medaka ?-actin/enhanced green fluorescent protein (EGFP) gene were subjected to enzymatic dissociation. These testicular cells were then stained with PKH26 and microinjected into the peritoneal cavity of the recipient fish. To confirm colonization of the donor-derived germ cells, the recipient gonads were examined by fluorescent and confocal microscopy. PKH26-labeled cells exhibiting typical spermatogonial morphology were incorporated into the recipient gonads and were not rejected within 22 days posttransplantation. Long-term survival of transgenic donor-derived germ cells was then verified in the gonads of 5-month-old recipients and in the milt and vitelogenic oocytes of 1-year-old recipients, by means of PCR using EGFP-specific primers. EGFP-positive milt from adult male recipients was used to fertilize non-transgenic oocytes and produced transgenic offspring expressing the donor-derived phenotype. These results imply that long-term survival, proliferation, and differentiation of the donor-derived spermatogonia into vitelogenic oocytes and functional spermatozoa are all possible. Upon further improvements in the transplantation efficiency, this intraperitoneal transplantation system could become a valuable tool in the conservation of genetic resources for cichlid species. PMID:24096828

Farlora, Rodolfo; Hattori-Ihara, Shoko; Takeuchi, Yukata; Hayashi, Makoto; Octavera, Anna; Alimuddin; Yoshizaki, Goro

2014-06-01

215

On the number of founding germ cells in humans  

PubMed Central

Background The number of founding germ cells (FGCs) in mammals is of fundamental significance to the fidelity of gene transmission between generations, but estimates from various methods vary widely. In this paper we obtain a new estimate for the value in humans by using a mathematical model of germ cell development that depends on available oocyte counts for adult women. Results The germline-development model derives from the assumption that oogonial proliferation in the embryonic stage starts with a founding cells at t = 0 and that the subsequent proliferation can be defined as a simple stochastic birth process. It follows that the population size X(t) at the end of germline expansion (around the 5th month of pregnancy in humans; t = 0.42 years) is a random variable with a negative binomial distribution. A formula based on the expectation and variance of this random variable yields a moment-based estimate of a that is insensitive to the progressive reduction in oocyte numbers due to their utilization and apoptosis at later stages of life. In addition, we describe an algorithm for computing the maximum likelihood estimation of the FGC population size (a), as well as the rates of oogonial division and loss to apoptosis. Utilizing both of these approaches to evaluate available oocyte-counting data, we have obtained an estimate of a = 2 – 3 for Homo sapiens. Conclusion The estimated number of founding germ cells in humans corresponds well with values previously derived from chimerical or mosaic mouse data. These findings suggest that the large variation in oocyte numbers between individual women is consistent with a smaller founding germ cell population size than has been estimated by cytological analyses. PMID:16120211

Zheng, Chang-Jiang; Luebeck, E Georg; Byers, Breck; Moolgavkar, Suresh H

2005-01-01

216

BMP signaling is required for the generation of primordial germ cells in an insect.  

PubMed

Two modes of germ cell formation are known in animals. Specification through maternally inherited germ plasm occurs in many well-characterized model organisms, but most animals lack germ plasm by morphological and functional criteria. The only known alternative mechanism is induction, experimentally described only in mice, which specify germ cells through bone morphogenetic protein (BMP) signal-mediated induction of a subpopulation of mesodermal cells. Until this report, no experimental evidence of an inductive germ cell signal for specification has been available outside of vertebrates. Here we provide functional genetic experimental evidence consistent with a role for BMP signaling in germ cell formation in a basally branching insect. We show that primordial germ cells of the cricket Gryllus bimaculatus transduce BMP signals and require BMP pathway activity for their formation. Moreover, increased BMP activity leads to ectopic and supernumerary germ cells. Given the commonality of BMP signaling in mouse and cricket germ cell induction, we suggest that BMP-based germ cell formation may be a shared ancestral mechanism in animals. PMID:24591634

Donoughe, Seth; Nakamura, Taro; Ewen-Campen, Ben; Green, Delbert A; Henderson, Lory; Extavour, Cassandra G

2014-03-18

217

Germ plasm in Eleutherodactylus coqui, a direct developing frog with large eggs  

PubMed Central

Background RNAs for embryo patterning and for germ cell specification are localized to the vegetal cortex of the oocyte of Xenopus laevis. In oocytes of the direct developing frog Eleutherodactylus coqui, orthologous RNAs for patterning are not localized, raising the question as to whether RNAs and other components of germ plasm are localized in this species. Methods To identify germ plasm, E. coqui embryos were stained with DiOC6(3) or examined by in situ hybridization for dazl and DEADSouth RNAs. The cDNAs for the E. coqui orthologues were cloned by RT-PCR using degenerate primers. To examine activity of the E. coqui orthologues, RNAs, made from constructs of their 3'UTRs with mCherry, were injected into X. laevis embryos. Results Both DiOC6(3) and dazl and DEADSouth in situs identified many small islands at the vegetal surface of cleaving E. coqui embryos, indicative of germ plasm. Dazl was also expressed in primordial germ cells in the genital ridge. The 3'UTRs of E. coqui dazl and DEADSouth directed primordial germ cell specific protein synthesis in X. laevis. Conclusions E. coqui utilizes germ plasm with RNAs localized to the vegetal cortex to specify primordial germ cells. The large number of germ plasm islands suggests that an increase in the amount of germ plasm was important in the evolution of the large E. coqui egg. PMID:21978790

2011-01-01

218

Evaluation of soybean RFLP marker diversity in adapted germ plasm.  

PubMed

Soybean RFLP markers have been primarily developed and genetically mapped using wide crosses between exotic and adapted genotypes. We have screened 38 soybean lines at 128 RFLP marker loci primarily to characterize germ plasm structure but also to evaluate the utility of RFLP markers identified in unadapted populations. Of these DNA probes 70% detected RFLPs in this set of soybean lines with an average polymorphism index of 0.30. This means that only 1 out of 5 marker loci was informative between any particular pair of adapted soybean lines. The variance associated with the estimation of RFLP genetic distance (GDR) was determined, and the value obtained suggested that the use of more than 65-90 marker loci for germ plasm surveys will add little precision. Cluster analysis and principal coordinate analysis of the GDR matrix revealed the relative lack of diversity in adapted germ plasm. Within the cultivated lines, several lines adapted to Southern US maturity zones also appeared as a separate group. GDR data was compared to the genetic distance estimates obtained from pedigree analysis (GDP). These two measures were correlated with r = 0.54 for all 38 lines, but the correlation increased to r = 0.73 when only adapted lines were analyzed. PMID:24197306

Keim, P; Beavis, W; Schupp, J; Freestone, R

1992-11-01

219

Layers and Layers  

NSDL National Science Digital Library

This lesson has students create their own rock layers by slowly adding and observing how different types of sediment interact when layered upon each other. This lesson is meant to illustrate how we can use these layers to discover the relative age of an object found in that layer by utilizing the Law of Superposition.

Cheri Tremarco

2011-10-07

220

Primary cilia in the developing pig testis.  

PubMed

In vertebrates, a variety of cell types generate a primary cilium. Cilia are implicated in determination and differentiation of a wide variety of organs and during embryonic development. However, there is little information on the presence or function of primary cilia in the mammalian testis. Therefore, the objective of this study was to characterize expression of primary cilia in the developing pig testis. Testicular tissue from pigs at 2-10 weeks of age was analyzed for primary cilia by immunocytochemistry. Expression of primary cilia was also analyzed in testicular tissue formed de novo from a single cell suspension ectopically grafted into a mouse host. Functionality of primary cilia was monitored based on cilia elongation after exposure to lithium. Analysis showed that the primary cilium is present in testis cords as well as in the interstitium of the developing pig testis. Germ cells did not express primary cilia. However, we identified Sertoli cells as one of the somatic cell types that produce a primary cilium within the developing testis. Primary cilium expression was reduced from the second to the third week of pig testis development in situ and during de novo morphogenesis of testis tissue from a single cell suspension after xenotransplantation. In vitro, primary cilia were elongated in response to lithium treatment. These results indicate that primary cilia on Sertoli cells may function during testicular development. De novo morphogenesis of testis tissue from single cell suspensions may provide an accessible platform to study and manipulate expression and function of primary cilia. PMID:25107611

Ou, Young; Dores, Camila; Rodriguez-Sosa, Jose-Rafael; van der Hoorn, Frans A; Dobrinski, Ina

2014-11-01

221

Windows for sex-specific methylation marked by DNA methyltransferase expression profiles in mouse germ cells  

Microsoft Academic Search

The acquisition of genomic methylation in the male germ line is initiated prenatally in diploid gonocytes, while DNA methylation in the female germ line is initiated postnatally in growing oocytes. We compared the temporal expression patterns of the DNA methyltransferases, DNMT1, DNMT3a, DNMT3b, and DNMT3l in the male and female germ lines. DNMT1 expression was examined by immunocytochemistry and Northerns

Sophie La Salle; Carmen Mertineit; Teruko Taketo; Peter B Moens; Timothy H Bestor; Jacquetta M Trasler

2004-01-01

222

Evaluation of corn germ protein as an extender in plywood adhesive  

Microsoft Academic Search

This study was conducted to evaluate the potential of wet-milled corn germ protein as an extender in plywood adhesive. Partially defatted dried corn germ from wet-milling, containing 2.1% (dry basis, db) crude oil and 24.7% (db) crude protein, was ground to 40-mesh particle size to produce the meal. The predominant water- and saline-soluble proteins were extracted from the corn germ

Mila P. Hojilla-Evangelista

2012-01-01

223

Retinoic acid induces mouse bone marrow-derived CD15?, Oct4? and CXCR4? stem cells into male germ-like cells in a two-dimensional cell culture system.  

PubMed

We have examined the effect of retinoic acid (RA) on differentiation of bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells into male germ cells. Bone marrow stem cells (BMSCs) were isolated from the femur of 3-4-week-old male C57BL/6 mice. Magnetic-activated cell sorting (MACS) system was used to sort CD15(+) , Oct4(+) and CXCR4(+) cells. RT-PCR was used to follow the expression of pluripotency markers. Sorted CD15(+) , Oct4(+) and CXCR4(+) cells were cultured in an undifferentiated condition on a feeder layer of mitomycin C-inactivated C2C12. The embryoid-like bodies were differentiated into male germ cells by retinoic acid. To identify the expression of male germ specific markers, differentiated cells were analysed by means of reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence staining. RT-PCR and immunofluorescence show that bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells express pluripotency markers, Oct4, Nanog, Rex-1, SOX-2 and AP. The purified CD15(+) , Oct4(+) and CXCR4(+) formed structures like embryoid bodies when plated over a feeder layer; these bodies were alkaline phosphatase positive. When cells were induced by RA, bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) were positive for Mvh, Dazl, Piwil2, Dppa3 and Stra8, that known molecular markers of male germ cells. Thus RA can induce differentiation of mouse bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells into male germ cells in vitro. Negative results for the gene expression analysis of female germ cells markers, GDF9 and ZP3, confirmed this conclusion. PMID:24677291

Kashani, Iraj Ragerdi; Zarnani, Amir Hassan; Soleimani, Masoud; Abdolvahabi, Mir Abbas; Nayernia, Karim; Shirazi, Reza

2014-06-01

224

Contribution of donor and host mesenchyme to the transplanted tooth germs.  

PubMed

Autologous tooth germ transplantation of immature teeth is an alternative method of tooth replacement that could be used instead of dental implants in younger patients. However, it is paramount that the dental pulp remain vital and that root formation continue in the transplanted location. The goal of this study is to characterize the healing of allogenic tooth grafts in an animal model using GFP-labeled donor or host postnatal mice. In addition, the putative stem cells were labeled before transplantation with a pulse-chase paradigm. Transplanted molars formed cusps and roots and erupted into occlusion by 2 wk postoperatively. Host label-retaining cells (LRCs) were maintained in the center of pulp tissue associating with blood vessels. Dual labeling showed that a proportion of LRCs were incorporated into the odontoblast layer. Host cells, including putative dendritic cells and the endothelium, also immigrated into the pulp tissue but did not contribute to the odontoblast layer. Therefore, LRCs or putative mesenchymal stem cells are retained in the transplanted pulps. Hertwig's epithelial root sheath remains vital, and epithelial LRCs are present in the donor cervical loops. Thus, the dynamic donor-host interaction occurred in the developing transplant, suggesting that these changes affect the characteristics of the dental pulp. PMID:25376722

Nakaki, T; Saito, K; Ida-Yonemochi, H; Nakagawa, E; Kenmotsu, S; Ohshima, H

2015-01-01

225

Aggregation behaviour and stability of maize germ oil body suspension.  

PubMed

To utilize maize germ oil bodies as ingredients in the food industry, zeta potential determination and particle diameter analysis were used in this study as indicators of the stability of maize germ oil body suspensions. The stability and aggregation properties of maize germ oil body suspensions were studied at different pH and ion strength conditions, and different thermal treatments. Zeta potential measurement, mean particle size determination, and confocal laser scanning microscopy were also performed. The zeta potential and mean particle diameter of the oil bodies were easily affected by salt (7.05 mV and d32=1.43 ?m at 100mM NaCl) and pH (23.30, 15.00, -16.43 mV and d32=1.02, 2.55, and 0.95 ?m at pH 3, pH 4, and pH 7, respectively). Results demonstrated that aggregation and instability of the oil bodies were promoted by high salt concentrations and acidic pH but not by heating. The association between oil bodies and surfactant properties resulted in the disruption of hydrophobic interactions among oil body surface proteins because of the smaller mean particle sizes and the reduced negative charges (-75.73 mV and d32=0.46 ?m at pH 3). Thus, the oil body aggregation behavior and stability of proteins are based on hydrophobic interactions present on the surface of the oil bodies. PMID:24996296

Sukhotu, Rujira; Shi, Xiaodi; Hu, Qi; Nishinari, Katsuyoshi; Fang, Yapeng; Guo, Shuntang

2014-12-01

226

Development and evolution of the vertebrate primary mouth  

PubMed Central

The vertebrate oral region represents a key interface between outer and inner environments, and its structural and functional design is among the limiting factors for survival of its owners. Both formation of the respective oral opening (primary mouth) and establishment of the food-processing apparatus (secondary mouth) require interplay between several embryonic tissues and complex embryonic rearrangements. Although many aspects of the secondary mouth formation, including development of the jaws, teeth or taste buds, are known in considerable detail, general knowledge about primary mouth formation is regrettably low. In this paper, primary mouth formation is reviewed from a comparative point of view in order to reveal its underestimated morphogenetic diversity among, and also within, particular vertebrate clades. In general, three main developmental modes were identified. The most common is characterized by primary mouth formation via a deeply invaginated ectodermal stomodeum and subsequent rupture of the bilaminar oral membrane. However, in salamander, lungfish and also in some frog species, the mouth develops alternatively via stomodeal collar formation contributed both by the ecto- and endoderm. In ray-finned fishes, on the other hand, the mouth forms via an ectoderm wedge and later horizontal detachment of the initially compressed oral epithelia with probably a mixed germ-layer derivation. A very intriguing situation can be seen in agnathan fishes: whereas lampreys develop their primary mouth in a manner similar to the most common gnathostome pattern, hagfishes seem to undergo a unique oropharyngeal morphogenesis when compared with other vertebrates. In discussing the early formative embryonic correlates of primary mouth formation likely to be responsible for evolutionary–developmental modifications of this area, we stress an essential role of four factors: first, positioning and amount of yolk tissue; closely related to, second, endoderm formation during gastrulation, which initiates the process and constrains possible evolutionary changes within this area; third, incipient structure of the stomodeal primordium at the anterior neural plate border, where the ectoderm component of the prospective primary mouth is formed; and fourth, the prime role of Pitx genes for establishment and later morphogenesis of oral region both in vertebrates and non-vertebrate chordates. PMID:22804777

Soukup, Vladimír; Horácek, Ivan; Cerny, Robert

2013-01-01

227

Development and evolution of the vertebrate primary mouth.  

PubMed

The vertebrate oral region represents a key interface between outer and inner environments, and its structural and functional design is among the limiting factors for survival of its owners. Both formation of the respective oral opening (primary mouth) and establishment of the food-processing apparatus (secondary mouth) require interplay between several embryonic tissues and complex embryonic rearrangements. Although many aspects of the secondary mouth formation, including development of the jaws, teeth or taste buds, are known in considerable detail, general knowledge about primary mouth formation is regrettably low. In this paper, primary mouth formation is reviewed from a comparative point of view in order to reveal its underestimated morphogenetic diversity among, and also within, particular vertebrate clades. In general, three main developmental modes were identified. The most common is characterized by primary mouth formation via a deeply invaginated ectodermal stomodeum and subsequent rupture of the bilaminar oral membrane. However, in salamander, lungfish and also in some frog species, the mouth develops alternatively via stomodeal collar formation contributed both by the ecto- and endoderm. In ray-finned fishes, on the other hand, the mouth forms via an ectoderm wedge and later horizontal detachment of the initially compressed oral epithelia with probably a mixed germ-layer derivation. A very intriguing situation can be seen in agnathan fishes: whereas lampreys develop their primary mouth in a manner similar to the most common gnathostome pattern, hagfishes seem to undergo a unique oropharyngeal morphogenesis when compared with other vertebrates. In discussing the early formative embryonic correlates of primary mouth formation likely to be responsible for evolutionary-developmental modifications of this area, we stress an essential role of four factors: first, positioning and amount of yolk tissue; closely related to, second, endoderm formation during gastrulation, which initiates the process and constrains possible evolutionary changes within this area; third, incipient structure of the stomodeal primordium at the anterior neural plate border, where the ectoderm component of the prospective primary mouth is formed; and fourth, the prime role of Pitx genes for establishment and later morphogenesis of oral region both in vertebrates and non-vertebrate chordates. PMID:22804777

Soukup, Vladimír; Horácek, Ivan; Cerny, Robert

2013-01-01

228

Primary Syphilis  

MedlinePLUS

newsletter | contact Share | Primary Syphilis Information for adults A A A This image displays a painless ulcer with a red base, typical of primary syphilis. Overview Primary syphilis is a disease caused by ...

229

Unraveling the molecular targets pertinent to junction restructuring events during spermatogenesis using the Adjudin-induced germ cell depletion model  

PubMed Central

During spermatogenesis, extensive restructuring takes place at the Sertoli–Sertoli and Sertoli–germ cell interface, which is regulated via intriguing interactions among cytokines, proteases, protease inhibitors, kinases, phosphatases, and transcription factors. This in turn determines the steady-state levels of integral membrane proteins at the cell junctions. We sought to further expand these observations using the Adjudin model. Adjudin is a potential male contraceptive that targets Sertoli–germ cell adhesion, causing exfoliation of spermatids and spermatocytes, but not spermatogonia, from the seminiferous epithelium. This model thus provides the means to identify crucial regulatory molecules and signaling pathways pertinent to junction restructuring events during spermatogenesis. In this study, genome-wide expression profiling of rat testes after treatment with Adjudin at the time of extensive junction restructuring was performed. Differentially regulated genes, such as cytokines, proteases, protease inhibitors, cell junction-associated proteins, and transcription factors pertinent to junction restructuring were identified. These data were consistent with earlier findings; however, much new information was obtained which has been deposited at the Gene Expression Omnibus data repository website: http://www.ncbi.nih.gov/geo/ with Accession number: GSE5131. The primary signaling events pertinent to junction restructuring in the testis induced by Adjudin were also delineated using bioinformatics. These findings were also consistent with recently published reports. The identified molecular signatures or targets pertinent to junction dynamics in the testis as reported herein, many of which have not been investigated, thus offer a framework upon which the regulation of junction restructuring events at the Sertoli–Sertoli and Sertoli–germ cell interface pertinent to spermatogenesis can be further studied. PMID:17332525

Xia, Weiliang; Mruk, Dolores D; Lee, Will M; Cheng, C Yan

2009-01-01

230

Survival outcomes for men with mediastinal germ-cell tumors: The University of Texas M. D. Anderson Cancer Center experience?  

PubMed Central

Objective Primary mediastinal germ-cell tumors are rare, and the effect of newer drugs and treatment strategies in this disease on overall survival is not known. We retrospectively assessed treatment outcomes at a single institution. Materials and methods We identified men seen at our institution from 1998 through 2005 for mediastinal germ-cell tumors. Medical records were reviewed for patient characteristics, histology, tumor markers, treatment, and survival outcome. Results Thirty-four patients met study criteria, of whom 27 had nonseminomatous germ-cell tumor (NSGCT) and 7 had pure seminoma. Eleven patients (41%) with NSGCT were alive at last contact with a median overall survival time of 33.5 months. Among 13 patients with NSGCT referred to us at initial diagnosis, 7 (54%) were alive and recurrence-free at a median follow-up of 56.5 months. Progression-free survival was associated with absence of risk factors (any histology other than endodermal sinus tumor, ?-hCG > 1000 mIU/mL, or disease outside the mediastinum). For the patients whose disease progressed (n = 5) or who had been referred to us for salvage treatment (n = 14), the 3-year overall survival from the date of first progression was 23%. Conversely, patients with seminoma did uniformly well with platinum-based chemotherapy; most did not undergo radiation or surgery. Conclusion Chemotherapy given to maximum effect followed by surgical consolidation resulted in long-term progression-free survival for 54% of patients with mediastinal NSGCT. The number of risk factors present at diagnosis may be associated with survival outcome and should be studied in a larger test group. PMID:20933444

Rodney, Alan J.; Tannir, Nizar M.; Siefker-Radtke, Arlene O.; Liu, Ping; Walsh, Garrett L.; Millikan, Randall E.; Swisher, Stephen G.; Tu, Shi-Ming; Pagliaro, Lance C.

2014-01-01

231

A Cytokinin-binding Protein from Wheat Germ  

PubMed Central

A cytokinin-binding protein has been isolated from wheat germ via ammonium sulfate precipitation, carboxymethyl Sephadex chromatography, and affinity chromatography on a column substituted with a derivative of kinetin riboside. On Sephadex G-200, the protein migrated with an apparent molecular weight of 122,000 daltons. The dissociation constant for kinetin was determined by equilibrium dialysis to be 1.2 micromolar; N6-benzylaminopurine and N6-(?2-isopentenyl)adenine were also strongly bound. Little affinity was exhibited toward either cis-zeatin or trans-zeatin. Images PMID:16661016

Moore, F. Hardy

1979-01-01

232

Susceptibility alleles for testicular germ cell tumour: a review.  

PubMed

Family history is among the strongest and most consistent of the risk factors for testicular germ cell tumour (TGCT). Brothers of affected cases have an 8- to10-fold relative risk and fathers/sons have a risk between four and sixfold. The familial relative risk of TGCT is higher than for most other cancer types, which rarely exceeds four. The high relative risk suggests that inherited susceptibility to TGCT may account for a substantial fraction of TGCT cases. The search for TGCT susceptibility genes has proven difficult and a recent genome-wide linkage study for TGCT susceptibility loci demonstrated no statistically significant regions of linkage with all LOD scores less than two. Moreover, a previous report of linkage to a region on Xq27 was not replicated. The results from genetic linkage analysis demonstrate that TGCT susceptibility is likely to be due to several genes, each with a modest effect on disease risk. The Y chromosome, which cannot be analysed by genetic linkage, carries a number of testis- and germ cell-specific genes. We recently demonstrated that a deletion on the Y chromosome known as 'gr/gr' is a rare, low-penetrance allele that is associated with susceptibility to TGCT. Based on the evidence from the linkage search the 'gr/gr' deletion represents one of possibly many TGCT susceptibility alleles, and new and emerging technologies will be employed in future work to identify these genes. PMID:17705805

Rapley, E

2007-08-01

233

Management of poor-prognosis testicular germ cell tumors  

PubMed Central

Currently, the outcome of patients with intermediate-and poor-risk germ cell tumors at diagnosis is optimized by the use of risk-appropriate chemotherapy and post-chemotherapy surgical resection of residual masses. Currently, there is no role for high-dose chemotherapy in the first-line setting. Patients who progress on first-line chemotherapy or who relapse after an initial complete response also have a poor prognosis. In the setting of early relapse, the standard approach at most centers is conventional-dose, ifosfamide-based regimens and post-chemotherapy resection of residual masses. The treatment of patients with late relapse is complete surgical resection whenever feasible. Salvage chemotherapy for late relapse may be used prior to surgery in patients where a complete resection is not feasible. A complete surgical resection of all residual sites of disease after chemotherapy is critical for the prevention of relapse and the long-term survival of patients with advanced germ cell tumors. PMID:20535296

Khurana, Kiranpreet; Gilligan, Timothy D.; Stephenson, Andrew J.

2010-01-01

234

SMARCB1/INI1 maternal germ line mosaicism in schwannomatosis.  

PubMed

Schwannomatosis is characterized by the development of multiple schwannomas of the nervous system, but without the occurrence of vestibular schwannomas. Most cases of schwannomatosis are thought to be sporadic, representing the first case in a family due to a new mutation in the causative gene. We recently identified SMARCB1/INI1 as a schwannomatosis-predisposing gene. Here, we analyzed this gene in a schwannomatosis family with two affected children, but with clinically unaffected parents. Both affected individuals carried a constitutional SMARCB1 mutation, c.1118+ 1G>A, that changes the donor splice site sequence of intron 8, causing skipping of exon 8 and resulting in the in-frame deletion of 132 nucleotides in the transcript. The mutation was not evident in constitutional DNA of the parents. Haplotyping revealed that the chromosome 22 segment that carries the mutant SMARCB1 allele originated from the mother. She transferred the same chromosome 22 segment, however, with a wild-type SMARCB1 copy, to a third unaffected child. Our findings indicate that the mother is germ line mosaic for the SMARCB1 mutation. In conclusion, our study shows for the first time that germ line mosaicism may occur in schwannomatosis, which has implications for genetic counseling in this disease. PMID:19912265

Hulsebos, T J M; Kenter, S B; Jakobs, M E; Baas, F; Chong, B; Delatycki, M B

2010-01-01

235

Properties of a terminal deoxyribonucleotidyltransferase isolated from wheat germ.  

PubMed

An enzyme able to catalyse the polymerization of deoxyribonucleotides in a template-independent manner was isolated from dry wheat germ. This activity is associated with a soluble protein which is homogeneous with respect to the molecular weight (approx. 500000) and, under denaturing conditions, dissociates into product of two size classes, 67000 and 45000 daltons respectively. The enzyme-catalysed polymerization can be primed by oligo- as well as poly-deoxyribonucleotides, and is highly efficient (234 nmol/h per mg of finally purified protein) when only one of the four deoxyribonucleoside 5'-triphosphates is present in the incubation mixture. An extension of the 3'-hydroxy termini of polydeoxyribonucleotide chains for approx. 40 nucleotide residues was achieved when non-denatured DNA and [3H]dTTP were used as the primer and substrate respectively. It is concluded that the enzyme isolated from wheat germ shares catalytic properties with the terminal deoxynucleotidyltransferase of mammalian thymus. Unlike that transferase, however, the plant enzyme prefers non-denatured to single-stranded DNA as primer and requires both Mg2+ and Mn2+ ions for maximal activity. PMID:7470090

Brodniewicz-Proba, T; Buchowicz, J

1980-10-01

236

GENETIC ANOMALIES IN MAMMALIAN GERM CELLS AND THEIR SIGNIFICANCE FOR HUMAN REPRODUCTIVE AND DEVELOPMENTAL RISK  

EPA Science Inventory

The induction of heritable mutations in germ cells represents a potential health concern. his paper will highlight several themes in the area of germ-cell mutagenesis and their implications in reproductive and developmental risk. dditionally, factors that influence the yield of g...

237

Derivation of embryonic germ cells and male gametes from embryonic stem cells  

Microsoft Academic Search

Egg and sperm cells (gametes) of the mouse are derived from a founder population of primordial germ cells that are set aside early in embryogenesis. Primordial germ cells arise from the proximal epiblast, a region of the early mouse embryo that also contributes to the first blood lineages of the embryonic yolk sac. Embryonic stem cells differentiate in vitro into

Niels Geijsen; Melissa Horoschak; Kitai Kim; Joost Gribnau; Kevin Eggan; George Q. Daley

2004-01-01

238

Mixed Malignant Germ Cell Tumour of Third Ventricle with Hydrocephalus: A Rare Case with Recurrence  

PubMed Central

Malignant Germ Cell Tumours (GCTs) are rare, accounting for 3% of intracranial tumours and just like their extracranial counterparts represent a wide array of disease. Combination of Germinoma with Teratoma is very rare. Here in, we describe a case of Mixed Malignant Germ cell tumor of third ventricle with recurrence with emphasis on histopathological and radiological findings. PMID:25584231

Monappa, Vidya; Rao, Lakshmi; Kudva, Ranjini

2014-01-01

239

Mixed malignant germ cell tumour of third ventricle with hydrocephalus: a rare case with recurrence.  

PubMed

Malignant Germ Cell Tumours (GCTs) are rare, accounting for 3% of intracranial tumours and just like their extracranial counterparts represent a wide array of disease. Combination of Germinoma with Teratoma is very rare. Here in, we describe a case of Mixed Malignant Germ cell tumor of third ventricle with recurrence with emphasis on histopathological and radiological findings. PMID:25584231

Kishore, Manjari; Monappa, Vidya; Rao, Lakshmi; Kudva, Ranjini

2014-11-01

240

Germ-Line Gene Modification and Disease Prevention: Some Medical and Ethical Perspectives  

Microsoft Academic Search

There has been considerable debate about the ethics of human germ-line gene modification. As a result of recent advances in the micromanipulation of embryos and the laboratory development of transgenic mice, a lively discussion has begun concerning both the technical feasibility and the ethical acceptability of human germ-line modification for the prevention of serious disease. This article summarizes some of

Nelson A. Wivel; Leroy Walters

1993-01-01

241

UTR of nanos2 directs enrichment in the germ cell lineage of the sea urchin  

E-print Network

The 30 UTR of nanos2 directs enrichment in the germ cell lineage of the sea urchin Nathalie Oulhen Keywords: Nanos Sea urchin Small micromeres Germ line RNA retention Translational regulation a b s t r a c during embryogenesis. Three nanos homologs are present in the genome of the sea urchin Strongylo

Wessel, Gary M.

242

Contribution of METRO pathway localized molecules to the organization of the germ cell lineage  

Microsoft Academic Search

To elucidate the potential role of localized components in the specification of the germ cell lineage we analyzed the composition of the germ plasm in Xenopus laevis oocytes and early embryos with respect to the vegetally-localized RNAs. We focused on Xlsirts, Xcat2, and Xwnt11 transcripts that are localized to the vegetal cortex through a region of the mitochondrial cloud called

Malgorzata Kloc; Carolyn Larabell; Agnes Pui-Yee Chan; Laurence D Etkin

1998-01-01

243

Digestive enzymes in the germ-free animal T. CORRING, Catherine JUSTE, C. SIMOES-NUNES  

E-print Network

Digestive enzymes in the germ-free animal T. CORRING, Catherine JUSTE, C. SIMOES-NUNES Laboratoire de Physiologie de la Nutrition, INRA, 78350 Jouy en Josas, France. Summary. The digestive physiology on digestive enzymes in the germ-free. The present paper analyzes these data. There is little information

Paris-Sud XI, Université de

244

Strange Notes from the LA Punk Underground: The Durability of Darby Crash and the Germs  

Microsoft Academic Search

: This essay examines the durability of Darby Crash, lead singer of the Germs, one of Los Angeles’s earliest punk bands. Crash committed suicide in 1980, but he and the Germs continue to fascinate those familiar with their music and story. This ongoing interest is the result of numerous factors, including the Germs’ music, Crash’s disturbing worldview and charisma, and

Peter Robert Brown

2011-01-01

245

Strange Notes from the LA Punk Underground: The Durability of Darby Crash and the Germs  

Microsoft Academic Search

This essay examines the durability of Darby Crash, lead singer of the Germs, one of Los Angeles’s earliest punk bands. Crash committed suicide in 1980, but he and the Germs continue to fascinate those familiar with their music and story. This ongoing interest is the result of numerous factors, including the Germs’ music, Crash’s disturbing worldview and charisma, and our

Peter Robert Brown

2011-01-01

246

Z .Chemical Geology 145 1998 153159 z /Geochemical Earth Reference Model GERM  

E-print Network

Z .Chemical Geology 145 1998 153­159 z /Geochemical Earth Reference Model GERM : description on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. The Z .GERM chemical Z . Z .reservoirs of the present-day Earth, from core to atmosphere; 2 present-day fluxes between

Langmuir, Charles H.

247

SYNAPTONEMAL COMPLEX DAMAGE AS A MEASURE OF CHEMICAL MUTAGEN EFFECTS ON MAMMALIAN GERM CELLS  

EPA Science Inventory

As heritable chromosome anomalies are implicated in a variety of human disabilities, their induction in germ cells by environmental chemicals is viewed as a threat to health. Synaptonemal complex (SC) analysis is a novel approach for the detection of germ-line chromosomal damage....

248

Germ cells are not required to establish the female pathway in mouse fetal gonads.  

PubMed

The fetal gonad is composed of a mixture of somatic cell lineages and germ cells. The fate of the gonad, male or female, is determined by a population of somatic cells that differentiate into Sertoli or granulosa cells and direct testis or ovary development. It is well established that germ cells are not required for the establishment or maintenance of Sertoli cells or testis cords in the male gonad. However, in the agametic ovary, follicles do not form suggesting that germ cells may influence granulosa cell development. Prior investigations of ovaries in which pre-meiotic germ cells were ablated during fetal life reported no histological changes during stages prior to birth. However, whether granulosa cells underwent normal molecular differentiation was not investigated. In cases where germ cell loss occurred secondary to other mutations, transdifferentiation of granulosa cells towards a Sertoli cell fate was observed, raising questions about whether germ cells play an active role in establishing or maintaining the fate of granulosa cells. We developed a group of molecular markers associated with ovarian development, and show here that the loss of pre-meiotic germ cells does not disrupt the somatic ovarian differentiation program during fetal life, or cause transdifferentiation as defined by expression of Sertoli markers. Since we do not find defects in the ovarian somatic program, the subsequent failure to form follicles at perinatal stages is likely attributable to the absence of germ cells rather than to defects in the somatic cells. PMID:23091613

Maatouk, Danielle M; Mork, Lindsey; Hinson, Ashley; Kobayashi, Akio; McMahon, Andrew P; Capel, Blanche

2012-01-01

249

Survey and Detection of Endophytic Fungi in Lolium Germ Plasm by Direct Staining and Aphid Assays  

Microsoft Academic Search

Wilson, A. D., Clement, S. L., and Kaiser, W. J. 1991. Survey and detection of endophytic fungi in Lolium germ plasm by direct staining and aphid assays. Plant Dis. 75:169-173. Clavicipitaceous anamorphic endophytes were detected in 28 of 85 accessions from five of eight species in a collection of Lolium germ plasm. Comparative descriptions of endophytic mycelium in seeds of

A. DAN WILSON; STEPHEN L. CLEMENT; WALTER J. KAISER

250

The use of laminar flow for obtaining germ-free mice.  

PubMed

Hysterectomy in a laminar-flow cabinet affords greater economy of time and effort in obtaining germ-free mice than other methods. No contamination has occurred during the surgical procedure or in the subsequent transfer of the neonates into germ-free isolators. PMID:1207038

Taylor, D M

1975-10-01

251

Focus Issue: From Egg to Egg--Cell Signaling in Germ Cells  

NSDL National Science Digital Library

In this Focus Issue of Science’s STKE, which complements the Science Special Issue on germ cells, we take a closer look at cell signaling in germ cells. STKE highlights the migration of germ cells with an article that describes the different mechanisms controlling primordial germ cell movement and survival in mice and flies. Another article describes a mechanism for mediating plant self-incompatibility through control of the pollen tube, to prevent inappropriate delivery of incompatible sperm to the ovule. A common feature found in each of the organisms discussed, be they animal, insect or plant, is that signals from the surrounding tissues control survival and migration of the germ cells or resulting gametes.

Elizabeth M. Adler (American Association for the Advancement of Science;Science's STKE REV); Nancy R. Gough (American Association for the Advancement of Science;Science's STKE REV)

2007-04-24

252

The role of BLIMP1 and its putative downstream target TFAP2C in germ cell development and germ cell tumours.  

PubMed

During the past years, much information has been gathered regarding the genetic and epigenetic programmes leading to the specification and maintenance of primordial germ cells. Expression of the transcriptional regulator BLIMP1 (PRDM1) is regarded as the main event in germ cell specification. BLIMP1 induces a set of target genes, one of them being transcription factor TFAP2C (AP-2?, Tcfap2c). In murine loss of function models Blimp1 and Tcfap2c share an identical phenotype, strengthening the assumption that they act in the same pathway. One major role of this pathway is the inhibition of somatic differentiation in germ cells. BLIMP1 and TFAP2C are also expressed in carcinoma in situ (CIS, IGCNU, TIN) and in seminoma. As pointed out herein, the presence of both proteins helps to explain the undifferentiated nature of these germ cell tumours. In addition, we performed a meta-analysis of high-throughput datasets searching for TFAP2C/Tcfap2c target genes. This analysis leads us to suggest Nanos3, Dmrt1 and Dnmt3b as potential TFAP2C/Tcfap2c target genes with relevance to germ cell development and germ cell tumours. PMID:21564135

Schäfer, S; Anschlag, J; Nettersheim, D; Haas, N; Pawig, L; Schorle, H

2011-08-01

253

Use of sourdough fermented wheat germ for enhancing the nutritional, texture and sensory characteristics of the white bread  

Microsoft Academic Search

Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5, isolated from wheat germ and selected based on the kinetics of acidification, were used as starters for the manufacture\\u000a of sourdough fermented wheat germ. A bread containing sourdough fermented wheat germ as an ingredient (SFWGB) was compared\\u000a to breads made with (raw wheat germ bread, RWGB) or without (wheat flour bread, WFB) raw

Carlo Giuseppe Rizzello; Luana Nionelli; Rossana Coda; Raffaella Di Cagno; Marco Gobbetti

2010-01-01

254

Identification of germ cell-specific genes in mammalian meiotic prophase  

PubMed Central

Background Mammalian germ cells undergo meiosis to produce sperm or eggs, haploid cells that are primed to meet and propagate life. Meiosis is initiated by retinoic acid and meiotic prophase is the first and most complex stage of meiosis when homologous chromosomes pair to exchange genetic information. Errors in meiosis can lead to infertility and birth defects. However, despite the importance of this process, germ cell-specific gene expression patterns during meiosis remain undefined due to difficulty in obtaining pure germ cell samples, especially in females, where prophase occurs in the embryonic ovary. Indeed, mixed signals from both germ cells and somatic cells complicate gonadal transcriptome studies. Results We developed a machine-learning method for identifying germ cell-specific patterns of gene expression in microarray data from mammalian gonads, specifically during meiotic initiation and prophase. At 10% recall, the method detected spermatocyte genes and oocyte genes with 90% and 94% precision, respectively. Our method outperformed gonadal expression levels and gonadal expression correlations in predicting germ cell-specific expression. Top-predicted spermatocyte and oocyte genes were both preferentially localized to the X chromosome and significantly enriched for essential genes. Also identified were transcription factors and microRNAs that might regulate germ cell-specific expression. Finally, we experimentally validated Rps6ka3, a top-predicted X-linked spermatocyte gene. Protein localization studies in the mouse testis revealed germ cell-specific expression of RPS6KA3, mainly detected in the cytoplasm of spermatogonia and prophase spermatocytes. Conclusions We have demonstrated that, through the use of machine-learning methods, it is possible to detect germ cell-specific expression from gonadal microarray data. Results from this study improve our understanding of the transition from germ cells to meiocytes in the mammalian gonad. Further, this approach is applicable to other tissues for which isolating cell populations remains difficult. PMID:23445120

2013-01-01

255

Oil separation from wet milled corn germ dispersions as part of aqueous oil extraction and aqueous enzymatic oil extraction  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oil was obtained from corn germ by aqueous extraction (AE). 100 g batches of germ were mixed with a buffer solution to a mass concentration of 5 to 20% germ, preheated under 2 atm. pressure (120oC), milled in a blender and then churned in an incubator/shaker to coalesce and float oil droplets. The ...

256

??????????????????????- ??????????????????????????????????????????????????????? Accumulation of gamma-aminobutyric acid (GABA) in non-waxy and waxy rice germ during water soaking ????? ?????????? ?????? ??????????? ???? ?????????????? ???????? ????????????  

Microsoft Academic Search

Rice germ contains protein, vitamins, minerals, dietary fiber and gamma- aminobutyric acid (GABA). GABA has been proved to be effective for lowering the blood pressure of human being. It has neurotransmission functions and tranquilizer effects. Determination of GABA in rice germ and brown rice were investigated by using low- amylose, high-amylose and waxy rice cultivars. Percentage of germ weight showed

Patcharee Tungtrakul; Vipa Surojanametakul; Ladda Wattanasiritham

257

Removal and isolation of germ-rich fractions from hull-less barley using a fitzpatrick comminuting mill  

Technology Transfer Automated Retrieval System (TEKTRAN)

A process was developed to produce a germ-enriched fraction from hull-less barley using a Fitzpatrick Comminuting Mill followed by sieving. Hulled and hull-less barleys contain 1.5-2.5% oil and, like wheat kernels which contain wheat germ oil, much of the oil in barley kernels is in the germ fracti...

258

Addition of Wheat Germ Oil to a Liquid Larval Diet for Rearing Improved Quality Oriental Fruit Flies (Diptera: Tephritidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat germ oil was added into a low waste larval liquid diet for rearing Bactrocera dorsalis (Hendel) to optimize the fruit fly performance. Various concentrations of 0.04, 0.07, 0.15, 0.30, and 0.66 % of wheat germ oil were evaluated. Results showed that the addition of wheat germ oil did not affec...

259

DDX3X, the X homologue of AZFa gene DDX3Y, expresses a complex pattern of transcript variants only in the male germ line.  

PubMed

DDX3X, the functional X homologue of the major AZFa gene, DDX3Y, belongs to the highly conserved PL10-subfamily of DEAD-box RNA helicase genes which are functionally conserved from yeast to man. They are mainly involved in cell cycle control and translation initiation control of gene transcripts with long 5'UTR extensions containing complex secondary structures. Interestingly, in humans both gene copies were found to be expressed at different phases of human spermatogenesis. Whereas DDX3Y transcripts are translated only in premeiotic male germ cells, the DDX3X protein is expressed only in postmeiotic spermatids. In this study, we found that the major class of DDX3X transcripts in human testis become activated first after meiosis and at a specific core promoter not active in somatic tissues and not present upstream of the DDX3Y homologue. Two alternative 5'UTR transcript lengths are subsequently produced by an additional testis-specific 5'UTR splicing event. Both transcripts are mainly processed for polyadenylation in their proximal 3'UTR. A minor transcript class starting at the same male germ line-specific core promoter produces primary transcripts with an extremely long 3'UTR (?17 kb), which is subsequently spliced at distinct sites resulting in six short 3'UTR splice variants (I-VI). Comparative analyses of the DDX3X transcripts in mouse and primates revealed that this complex pattern of male germ line-specific transcript variants first evolved in primates. Our data thus suggest complex translational control mechanism(s) for the human DDX3X gene locus functioning only in the male germ line and resulting in expression of its protein only in the postmeiotic spermatids. PMID:25208899

Rauschendorf, Marc-Alexander; Zimmer, Jutta; Ohnmacht, Caroline; Vogt, Peter H

2014-12-01

260

Primitive neuroectodermal tumors in patients with testicular germ cell tumors usually resemble pediatric-type central nervous system embryonal neoplasms and lack chromosome 22 rearrangements.  

PubMed

Primitive neuroectodermal tumors (PNETs) are one of the most frequent types of 'non-germ cell' tumor in patients with testicular germ cell tumors and have a guarded prognosis when present in metastatic sites after cisplatin-based chemotherapy. Improved treatments, including targeted therapy, require understanding the biology of these neoplasms. We therefore analyzed the morphologic, immunohistochemical and molecular biologic features of 14 PNETs from 14 patients with concurrent or previous testicular germ cell tumors; 12 tumors were from metastatic sites and 2 were primary in the testis. Using standard light microscopic criteria for central nervous system and peripheral PNETs, we classified nine tumors as medulloepithelioma, three as medulloblastoma/supratentorial PNET, one as neuroblastic tumor with abundant neuropil and true rosettes and one as small cell embryonal tumor/PNET (Ewing sarcoma-like). Immunostains directed against INI1, CD57, S-100 protein, NeuN, WT1, neurofilament, CD99, GFAP, synaptophysin, chromogranin, AE1/AE3 cytokeratin, Fli-1 and collagen IV were performed for each case. INI1 was diffusely and strongly positive in all tumors whereas the other stains, except for cytoplasmic WT1 (which showed substantial reactivity in most tumors), were mostly focal to negative, including CD99 (eight negative, six focal) and Fli-1 (all negative). The most consistently reactive 'neuroendocrine' marker was CD57. Each case was also analyzed for chromosome 22 rearrangements using a FISH-based break-apart probe method. Only 1 tumor, classified as medulloepithelioma, was scored positive for chromosome 22 translocation (22% rearranged cells) and the remaining 13 were negative, including the one case that resembled peripheral PNET. We conclude that PNETs derived from testicular germ cell tumors mostly resemble central nervous system PNETs and generally lack the chromosome 22 translocation of peripheral PNETs. Future treatment strategies should take these findings into account. PMID:20348883

Ulbright, Thomas M; Hattab, Eyas M; Zhang, Shaobo; Ehrlich, Yaron; Foster, Richard S; Einhorn, Lawrence H; Cheng, Liang

2010-07-01

261

The story of a largely unknown evolution – Germ theory hoax  

PubMed Central

The Piltdown Man debacle provides us with the most infamous forgery in science. However, another equally intriguing story exists concerning a document by a Bostonian called George Sleeper, which purported to be a pre-Darwin–Wallace anticipation of evolution and an equally convincing account of the germ theory published before Louis Pasteur’s famous studies on this subject. The story involves two giants in the world of evolutionary theory, Alfred Russel Wallace and E.B. Poulton. While Wallace was convinced that the Sleeper document was genuine, Poulton’s detailed investigations showed that it was a fake and a hoax. Despite this conclusion, doubts still exist about the authenticity of the Sleeper document. PMID:23961141

Wainwright, Milton; Alharbi, Sulaiman Ali

2011-01-01

262

Mammalian DNMTs in the male germ line DNA of Drosophila.  

PubMed

It is controversial whether DNA methylation plays a functional role in Drosophila. We have studied testis DNA of Drosophila melanogaster Meigen, 1830 with antisera against 5-methylcytosine (5mC) and found no evidence for the presence of significant amounts of 5mC. Reactions occur only with 1 of 3 5mC antisera, but they are restricted to nuclear regions without detectable amounts of DNA. The antisera apparently cross-react with other nuclear components. If the murine de novo DNA methyltransferases, DNMT3A and DNMT3B, are expressed under the control of the spermatocyte-specific beta2-tubulin promoter in testes, DNA methylation is not increased and no effects on the fertility of the fly are seen. DNA methylation has, therefore, no functional relevance in the male germ line of Drosophila. PMID:18923539

Weyrich, Alexandra; Tang, Xiaojing; Xu, Guoliang; Schrattenholz, André; Hunzinger, Christian; Hennig, Wolfgang

2008-10-01

263

Development of interspecies testicular germ-cell transplantation in flatfish.  

PubMed

Interspecific testicular germ cell (TGC) transplantation was investigated in two commercial flatfish species. Testes from donor species (Senegalese sole) were evaluated using classical histological techniques (haematoxylin-eosin staining and haematoxylin-light green-orange G-acid fuchsine staining), in situ hybridisation and immunohistochemical analysis. Both Ssvasa1-2 mRNAs and SsVasa protein allowed the characterisation of TGCs, confirming the usefulness of the vasa gene in the detection of Senegalese sole TGCs. Xenogenic transplants were carried out using TGCs from one-year-old Senegalese sole into turbot larvae. Propidium iodide-SYBR-14 and 4',6'-diamidino-2-phenylindole (DAPI) staining showed that 87.98% of the extracted testicular cells were viable for microinjection and that 15.63% of the total recovered cells were spermatogonia. The vasa gene was characterised in turbot recipients using cDNA cloning. Smvasa mRNA was confirmed as a germ cell-specific molecular marker in this species. Smvasa expression analysis during turbot ontogeny was carried out before Senegalese sole TGC transplants into turbot larvae. Turbot larvae at 18 days after hatching (DAH) proved to be susceptible to manipulation procedures. High survival rates (83.75±15.90-100%) were obtained for turbot larvae at 27, 34 and 42 DAH. These data highlight the huge potential of this species for transplantation studies. Quantitative PCR was employed to detect Senegalese sole vasa mRNAs (Ssvasa1-2) in the recipient turbot larvae. The Ssvasa mRNAs showed a significant increase in relative expression in 42-DAH microinjected larvae three weeks after treatment, showing the proliferation of Senegalese sole spermatogonia in transplanted turbot larvae. PMID:23735683

Pacchiarini, Tiziana; Sarasquete, Carmen; Cabrita, Elsa

2014-06-01

264

Intra- and Interindividual Epigenetic Variation in Human Germ Cells  

PubMed Central

Epigenetics represents a secondary inheritance system that has been poorly investigated in human biology. The objective of this study was to perform a comprehensive analysis of DNA methylation variation between and within the germlines of normal males. First, methylated cytosines were mapped using bisulphite modification–based sequencing in the promoter regions of the following disease genes: presenilins (PSEN1 and PSEN2), breast cancer (BRCA1 and BRCA2), myotonic dystrophy (DM1), and Huntington disease (HD). Major epigenetic variation was detected within samples, since the majority of sperm cells of the same individual exhibited unique DNA methylation profiles. In the interindividual analysis, 41 of 61 pairwise comparisons revealed distinct DNA methylation profiles (P=.036 to 6.8 × 10?14). Second, a microarray-based epigenetic profiling of the same sperm samples was performed using a 12,198-feature CpG island microarray. The microarray analysis has identified numerous DNA methylation–variable positions in the germ cell genome. The largest degree of variation was detected within the promoter CpG islands and pericentromeric satellites among the single-copy DNA fragments and repetitive elements, respectively. A number of genes, such as EED, CTNNA2, CALM1, CDH13, and STMN2, exhibited age-related DNA methylation changes. Finally, allele-specific methylation patterns in CDH13 were detected. This study provides evidence for significant epigenetic variability in human germ cells, which warrants further research to determine whether such epigenetic patterns can be efficiently transmitted across generations and what impact inherited epigenetic individuality may have on phenotypic outcomes in health and disease. PMID:16773567

Flanagan, James M.; Popendikyte, Violeta; Pozdniakovaite, Natalija; Sobolev, Martha; Assadzadeh, Abbas; Schumacher, Axel; Zangeneh, Masood; Lau, Lynette; Virtanen, Carl; Wang, Sun-Chong; Petronis, Arturas

2006-01-01

265

Isolation and Enrichment of Mouse Female Germ Line Stem Cells  

PubMed Central

Objective The existence of female germ-line stem cells (FGSCs) has been the subject of a wide range of recent studies. Successful isolation and culture of FGSCs could facilitate studies on regenerative medicine and infertility treatments in the near future. Our aim in the present study was evaluation of the most commonly used techniques in enrichment of FGSCs and in establishment of the best procedure. Materials and Methods In this experimental study, after digesting neonate ovary from C57Bl/6 mice, we performed 2 different isolation experiments: magnetic activated cell sorting (MACS) and pre-plating. MACS was applied using two different antibodies against mouse vasa homolog (MVH) and stage-specific embryonic antigen-1 (SSEA1) markers. After the cells were passaged and proliferated in vitro, colony-forming cells were characterized using reverse transcription-polymerase chain reaction (RT-PCR) (for analysis of expression of Oct4, Nanog, C-kit, Fragilis, Mvh, Dazl, Scp3 and Zp3), alkaline phosphatase (AP) activity test and immunocytochemistry. Results Data showed that colonies can be seen more frequently in pre-plating technique than that in MACS. Using the SSEA1 antibody with MACS, 1.98 ± 0.49% (Mean ± SDV) positive cells were yield as compared to the total cells sorted. The colonies formed after pre-plating expressed pluripotency and germ stem cell markers (Oct4, Nanog, C-kit, Fragilis, Mvh and Dazl) whereas did not express Zp3 and Scp3 at the mRNA level. Immunocytochemistry in these colonies further confirmed the presence of OCT4 and MVH proteins, and AP activity measured by AP-kit showed positive reaction. Conclusion We established a simple and an efficient pre-plating technique to culture and to enrich FGSCs from neonatal mouse ovaries.

Khosravi-Farsani, Somayeh; Amidi, Fardin; Habibi Roudkenar, Mehryar; Sobhani, Aligholi

2015-01-01

266

Cellular analyses of the mitotic region in the Caenorhabditis elegans adult germ line.  

PubMed

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. First, all germ cells within the mitotic region are actively cycling, as visualized by bromodeoxyuridine (BrdU) labeling. No quiescent cells were found. Second, germ cells in the mitotic region lose BrdU label uniformly, either by movement of labeled cells into the meiotic region or by dilution, probably due to replication. No label-retaining cells were found in the mitotic region. Third, the distal tip cell niche extends processes that nearly encircle adjacent germ cells, a phenomenon that is likely to anchor the distal-most germ cells within the niche. Fourth, germline mitoses are not oriented reproducibly, even within the immediate confines of the niche. We propose that germ cells in the distal-most rows of the mitotic region serve as stem cells and more proximal germ cells embark on the path to differentiation. We also propose that C. elegans adult germline stem cells are maintained by proximity to the niche rather than by programmed asymmetric divisions. PMID:16672375

Crittenden, Sarah L; Leonhard, Kimberly A; Byrd, Dana T; Kimble, Judith

2006-07-01

267

TAp73 is essential for germ cell adhesion and maturation in testis  

PubMed Central

A core evolutionary function of the p53 family is to protect the genomic integrity of gametes. However, the role of p73 in the male germ line is unknown. Here, we reveal that TAp73 unexpectedly functions as an adhesion and maturation factor of the seminiferous epithelium orchestrating spermiogenesis. TAp73 knockout (TAp73KO) and p73KO mice, but not ?Np73KO mice, display a “near-empty seminiferous tubule” phenotype due to massive premature loss of immature germ cells. The cellular basis of this phenotype is defective cell–cell adhesions of developing germ cells to Sertoli nurse cells, with likely secondary degeneration of Sertoli cells, including the blood–testis barrier, which leads to disruption of the adhesive integrity and maturation of the germ epithelium. At the molecular level, TAp73, which is produced in germ cells, controls a coordinated transcriptional program of adhesion- and migration-related proteins including peptidase inhibitors, proteases, receptors, and integrins required for germ–Sertoli cell adhesion and dynamic junctional restructuring. Thus, we propose the testis as a unique organ with strict division of labor among all family members: p63 and p53 safeguard germ line fidelity, whereas TAp73 ensures fertility by enabling sperm maturation. PMID:24662569

Holembowski, Lena; Kramer, Daniela; Riedel, Dietmar; Sordella, Raffaella; Nemajerova, Alice; Dobbelstein, Matthias

2014-01-01

268

NOTCH1 Gain of Function in Germ Cells Causes Failure of Spermatogenesis in Male Mice  

PubMed Central

NOTCH1 is a member of the NOTCH receptor family, a group of single-pass trans-membrane receptors. NOTCH signaling is highly conserved in evolution and mediates communication between adjacent cells. NOTCH receptors have been implicated in cell fate determination, as well as maintenance and differentiation of stem cells. In the mammalian testis expression of NOTCH1 in somatic and germ cells has been demonstrated, however its role in spermatogenesis was not clear. To study the significance of NOTCH1 in germ cells, we applied a cre/loxP approach in mice to induce NOTCH1 gain- or loss-of function specifically in male germ cells. Using a Stra8-icre transgene we produced mice with conditional activation of the NOTCH1 intracellular domain (NICD) in germ cells. Spermatogenesis in these mutants was progressively affected with age, resulting in decreased testis weight and sperm count. Analysis of downstream target genes of NOTCH1 signaling showed an increased expression of Hes5, with a reduction of the spermatogonial differentiation marker, Neurog3 expression in the mutant testis. Apoptosis was significantly increased in mouse germ cells with the corresponding elevation of pro-apoptotic Trp53 and Trp63 genes' expression. We also showed that the conditional germ cell-specific ablation of Notch1 had no effect on spermatogenesis or male fertility. Our data suggest the importance of NOTCH signaling regulation in male germ cells for their survival and differentiation. PMID:23936265

Huang, Zaohua; Rivas, Bryan; Agoulnik, Alexander I.

2013-01-01

269

Differentiation of Human Embryonic Stem Cells into Embryoid Bodies Comprising the Three Embryonic Germ Layers  

Microsoft Academic Search

Background: Embryonic stem (ES) cells are lines of cells that are isolated from blastocysts. The murine ES cells were demonstrated to be true pluripotent cells as they differentiate into all embry- onic lineages. Yet, in vitro differentiation of rhesus ES cells was somewhat inconsistent and disorga- nized. The recent isolation of human ES cells calls for exploring their pluripotential nature.

Joseph Itskovitz-Eldor

2000-01-01

270

Malignant germ cell tumours of the testis express interferon-gamma, but are resistant to endogenous interferon-gamma.  

PubMed

Cytokines possess discrepant effects on tumour cells varying from anti- to proapoptotic activities. We recently reported that testicular germ cell tumours (TGCT) express a functional form of the proinflammatory cytokine interferon-gamma (IFNgamma). The present study asked whether TGCT-derived IFNgamma influences survival or death of neoplastic germ cells. Analysis of TGCT cell lines demonstrated that they expressed and secreted IFNgamma, but were resistant to the endogenous IFNgamma since neutralisation of IFNgamma by a specific blocking antibody had no influence on the proliferation and/or the degree of apoptosis of tumour cells. To study mechanisms providing tumour resistance to endogenous IFNgamma, we analysed primary TGCT and two human TGCT cell lines (NTERA and NCCIT) for the expression of IFNgamma receptor and for the level of phosphorylation of the signal transducer and activator of transcription (STAT)-1. In situ hybridisation, immunocytochemistry, Western blot analysis and flow cytometry indicated that primary TGCT as well as NCCIT and NTERA cell lines expressed the heterodimeric cell surface IFNgamma receptor which consists of both 90-kDa alpha- and the 85-kDa beta-chains. However, the downstream transcription factor STAT-1 was not phosphorylated constitutively, indicating that STAT-1 is not activated by the endogenous IFNgamma. Upon application of recombinant human IFNgamma in excess, however, STAT-1 was phosphorylated and the interferon regulatory factor-1 (IRF-1) was induced, suggesting that both IFNgammaR and STAT-1 are functionally intact in TGCT. Altogether our results suggest that despite secreting biologically active IFNgamma, the concentration of the endogenous IFNgamma is too low to stimulate the IFNgammaR/STAT signalling pathway in TGCT in an autocrine and/or paracrine manner. PMID:12942126

Schweyer, S; Soruri, A; Peters, J; Wagner, A; Radzun, H J; Fayyazi, A

2003-09-01

271

Current Biology 19, 414422, March 10, 2009 2009 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2009.01.038 Bucky Ball Organizes Germ  

E-print Network

[1, 2]. During oogenesis, germ plasm forms a distinct cellular structure such as pole plasm, at the beginning of zebrafish oogenesis, the germ plasm defect in bucky ball (buc) mutants precedes the loss during oogenesis and with the germ plasm during early embryogenesis, consistent with a role in germ plasm

Alwes, Frederike

272

Germ Tube Mediated Invasion of Batrachochytrium dendrobatidis in Amphibian Skin Is Host Dependent  

PubMed Central

Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines. We focussed on the early stages of infection by Bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. Skin explants of Alytes muletensis, Litoria caerulea and Xenopus leavis were exposed to Bd in an Ussing chamber for 3 to 5 days. Early interactions of Bd with amphibian skin were observed using light microscopy and transmission electron microscopy. To validate the observations in vitro, comparison was made with skin from experimentally infected frogs. Additional in vitro experiments were performed to elucidate the process of intracellular colonization in L. caerulea. Early interactions of Bd with amphibian skin are: attachment of zoospores to host skin, zoospore germination, germ tube development, penetration into skin cells, invasive growth in the host skin, resulting in the loss of host cell cytoplasm. Inoculation of A. muletensis and L. caerulea skin was followed within 24 h by endobiotic development, with sporangia located intracellularly in the skin. Evidence is provided of how intracellular colonization is established and how colonization by Bd proceeds to deeper skin layers. Older thalli develop rhizoid-like structures that spread to deeper skin layers, form a swelling inside the host cell to finally give rise to a new thallus. In X. laevis, interaction of Bd with skin was limited to an epibiotic state, with sporangia developing upon the skin. Only the superficial epidermis was affected. Epidermal cells seemed to be used as a nutrient source without development of intracellular thalli. The in vitro data agreed with the results obtained after experimental infection of the studied frog species. These data suggest that the colonization strategy of B. dendrobatidis is host dependent, with the extent of colonization most likely determined by inherent characteristics of the host epidermis. PMID:22911798

Van Rooij, Pascale; Martel, An; D'Herde, Katharina; Brutyn, Melanie; Croubels, Siska; Ducatelle, Richard; Haesebrouck, Freddy; Pasmans, Frank

2012-01-01

273

Germ-line DICER1 mutations do not make a major contribution to the etiology of familial testicular germ cell tumours  

PubMed Central

Background The RNase III enzyme DICER1 plays a central role in maturation of microRNAs. Identification of neoplasia-associated germ-line and somatic mutations in DICER1 indicates that mis-expression of miRNAs in cancer may result from defects in their processing. As part of a recent study of DICER1 RNase III domains in 96 testicular germ cell tumors, a single RNase IIIb domain mutation was identified in a seminoma. To further explore the importance of DICER1 mutations in the etiology of testicular germ cell tumors (TGCT), we studied germ-line DNA samples from 43 probands diagnosed with familial TGCT. Findings We carried out High Resolution Melting Curve Analysis of DICER1 exons 2–12, 14–19, 21 and 24–27. All questionable melt curves were subjected to confirmatory Sanger sequencing. Sanger sequencing was used for exons 13, 20, 22 and 23. Intron-exon boundaries were included in all analyses. We identified 12 previously reported single nucleotide polymorphisms and two novel single nucleotide variants. No likely deleterious variants were identified; notably no mutations that were predicted to truncate the protein were identified. Conclusions Taken together with previous studies, the findings reported here suggest a very limited role for either germ-line or somatic DICER1 mutations in the etiology of TGCT. PMID:23547758

2013-01-01

274

Examination of plants in lunar (germ free) soil in Plant Laboratory  

NASA Technical Reports Server (NTRS)

Dr. Charles Walkenshaw, Manned Spacecraft Center botanist, examines sorghum and tobacco plants in lunar (germ free) soil in the Plant Laboratory of the Lunar Receiving Laboratory. The soil was brought back from the Moon by the Apollo 11 astronauts.

1969-01-01

275

Analysis of Maize Seed Germs by Photoacoustic Microscopy and Photopyroelectric Technique  

NASA Astrophysics Data System (ADS)

A knowledge about thermal parameters of structural components of maize seed is of great relevance in the seed technology practice. The objective of the present study was to determine the thermal effusivity of germs of maize ( Zea mays L.) of different genotypes by means of the photopyroelectric technique (PPE) in the inverse configuration and obtaining the thermal imaging of these samples by photoacoustic microscopy (PAM). Germs from crystalline maize (white pigment), semi-crystalline maize (yellow pigment), and floury maize (blue pigment) were used in this investigation. The results show differences between germs of maize seeds mainly in the values of their thermal effusivities. The thermal images showed minimum inhomogeneity of these seed germs. Characterizations of thermal parameters in seeds are important in agriculture and food production and could be particularly useful to define their quality and determine their utility. PPE and PAM can be considered as potential diagnostic tools for the characterization of agriculture seeds.

Pacheco, A. Domínguez; Aguilar, C. Hernández; Cruz-Orea, A.

2013-05-01

276

Identification of germ plasm-associated transcripts by microarray analysis of Xenopus vegetal cortex RNA.  

PubMed

RNA localization is a common mechanism for regulating cell structure and function. Localized RNAs in Xenopus oocytes are critical for early development, including germline specification by the germ plasm. Despite the importance of these localized RNAs, only approximately 25 have been identified and fewer are functionally characterized. Using microarrays, we identified a large set of localized RNAs from the vegetal cortex. Overall, our results indicate a minimum of 275 localized RNAs in oocytes, or 2-3% of maternal transcripts, which are in general agreement with previous findings. We further validated vegetal localization for 24 candidates and further characterized three genes expressed in the germ plasm. We identified novel germ plasm expression for reticulon 3.1, exd2 (a novel exonuclease-domain encoding gene), and a putative noncoding RNA. Further analysis of these and other localized RNAs will likely identify new functions of germ plasm and facilitate the identification of cis-acting RNA localization elements. PMID:20503379

Cuykendall, Tawny N; Houston, Douglas W

2010-06-01

277

Restroom Hand Dryers Spread More Germs Than Paper Towels, Study Finds  

MedlinePLUS

... features on this page, please enable JavaScript. Restroom Hand Dryers Spread More Germs Than Paper Towels, Study ... Nov. 21, 2014 (HealthDay News) -- Those air-blown hand dryers in public restrooms may spread far more ...

278

Fine-structural characteristics of female and male germ cells in Proseriata Otoplanidae (Platyhelminthes)  

Microsoft Academic Search

Fine-structural features of female germ cells differentiating within the germaria of Otoplanella baltica and Notocaryoplanella glandulosa are documented and compared with those of other free-living platyhelminths having ectolecithal eggs.

Beate Sopott Ehlers

1986-01-01

279

Autophagy is a cell survival program for female germ cells in the murine ovary.  

PubMed

It is estimated that infertility affects 15-20% of couples and can arise from female or male reproductive defects. Mouse models have ascribed roles to over 100 genes in the maintenance of female fertility. Although previous models have determined roles for apoptosis in male and female fertility, we find that compromised autophagy within the perinatal ovary, through the loss of Becn1 or Atg7, results in the premature loss of female germ cells. Becn1(+/-) ovaries have a 56% reduction of germ cells compared with control ovaries at post-natal day 1, whereas Atg7(-/-) ovaries lack discernable germ cells at this stage. Thus autophagy appears to be a cell survival mechanism to maintain the endowment of female germ cells prior to establishing primordial follicle pools in the ovary. PMID:21464117

Gawriluk, Thomas R; Hale, Amber N; Flaws, Jodi A; Dillon, Christopher P; Green, Douglas R; Rucker, Edmund B

2011-06-01

280

The control of cell cycle in mouse primordial germ cells: old and new players.  

PubMed

The cell cycle of primordial germ cells (PGCs), the embryonic precursors of gametes, is characterized by a mitotic phase common to both sexes and a mitotic-meiotic switch in the female. In the present work, we will review the results obtained in the last decade by studies aimed to clarify intrinsic and extrinsic regulatory signals of such processes, with particular reference to mouse PGCs. Besides providing a better understanding of how the gamete population is established in mammals, information about the players controlling the PGC cycle will be useful to clarify other intriguing aspects of germ cell biology such as the origin of germ cell tumours and the mechanisms allowing the maintenance of totipotency in the germ line. PMID:22229562

De Felici, Massimo; Farini, Donatella

2012-01-01

281

Modeling cell elongation during germ band retraction: cell autonomy versus applied anisotropic stress  

NASA Astrophysics Data System (ADS)

The morphogenetic process of germ band retraction in Drosophila embryos involves coordinated movements of two epithelial tissues—germ band and amnioserosa. The germ band shortens along its rostral-caudal or head-to-tail axis, widens along its perpendicular dorsal-ventral axis, and uncurls from an initial ‘U’ shape. The amnioserosa mechanically assists this process by pulling on the crook of the U-shaped germ band. The amnioserosa may also provide biochemical signals that drive germ band cells to change shape in a mechanically autonomous fashion. Here, we use a finite-element model to investigate how these two contributions reshape the germ band. We do so by modeling the response to laser-induced wounds in each of the germ band’s spatially distinct segments (T1-T3, A1-A9) during the middle of retraction when segments T1-A3 form the ventral arm of the ‘U’, A4-A7 form its crook, and A8-A9 complete the dorsal arm. We explore these responses under a range of externally applied stresses and internal anisotropy of cell edge tensions—akin to a planar cell polarity that can drive elongation of cells in a direction parallel to the minimum edge tension—and identify regions of parameter space (edge-tension anisotropy versus stress anisotropy) that best match previous experiments for each germ band segment. All but three germ band segments are best fit when the applied stress anisotropy and the edge-tension anisotropy work against one another—i.e., when the isolated effects would elongate cells in perpendicular directions. Segments in the crook of the germ band (A4-A7) have cells that elongate in the direction of maximum external stress, i.e., external stress anisotropy is dominant. In most other segments, the dominant factor is internal edge-tension anisotropy. These results are consistent with models in which the amnioserosa pulls on the crook of the germ band to mechanically assist retraction. In addition, they suggest a mechanical cue for edge-tension anisotropy whereby cells do not globally orient their internal elongation axis towards the amnioserosa, but instead orient this axis perpendicular to the local principal stress direction.

Lynch, Holley E.; Veldhuis, Jim; Brodland, G. Wayne; Hutson, M. Shane

2014-05-01

282

An Integrative Omics Strategy to Assess the Germ Cell Secretome and to Decipher Sertoli-Germ Cell Crosstalk in the Mammalian Testis  

PubMed Central

Mammalian spermatogenesis, which takes place in complex testicular structures called seminiferous tubules, is a highly specialized process controlled by the integration of juxtacrine, paracrine and endocrine information. Within the seminiferous tubules, the germ cells and Sertoli cells are surrounded by testicular fluid (TF), which probably contains most of the secreted proteins involved in crosstalk between these cells. It has already been established that germ cells can modulate somatic Sertoli cell function through the secretion of diffusible factors. We studied the germ cell secretome, which was previously considered inaccessible, by analyzing the TF collected by microsurgery in an “integrative omics” strategy combining proteomics, transcriptomics, genomics and interactomics data. This approach identified a set of proteins preferentially secreted by Sertoli cells or germ cells. An interaction network analysis revealed complex, interlaced cell-cell dialog between the secretome and membranome of seminiferous cells, mediated via the TF. We then focused on germ cell-secreted candidate proteins, and we identified several potential interacting partners located on the surface of Sertoli cells. Two interactions, APOH/CDC42 and APP/NGFR, were validated in situ, in a proximity ligation assay (PLA). Our results provide new insight into the crosstalk between germ cells and Sertoli cells occurring during spermatogenesis. Our findings also demonstrate that this “integrative omics” strategy is powerful enough for data mining and highlighting meaningful cell-cell communication events between different types of cells in a complex tissue, via a biological fluid. This integrative strategy could be applied more widely, to gain access to secretomes that have proved difficult to study whilst avoiding the limitations of in vitro culture. PMID:25111155

Lavigne, Régis; Hernio, Nolwen; Teixeira-Gomes, Ana-Paula; Dacheux, Jean-Louis; Pineau, Charles

2014-01-01

283

An integrative omics strategy to assess the germ cell secretome and to decipher sertoli-germ cell crosstalk in the Mammalian testis.  

PubMed

Mammalian spermatogenesis, which takes place in complex testicular structures called seminiferous tubules, is a highly specialized process controlled by the integration of juxtacrine, paracrine and endocrine information. Within the seminiferous tubules, the germ cells and Sertoli cells are surrounded by testicular fluid (TF), which probably contains most of the secreted proteins involved in crosstalk between these cells. It has already been established that germ cells can modulate somatic Sertoli cell function through the secretion of diffusible factors. We studied the germ cell secretome, which was previously considered inaccessible, by analyzing the TF collected by microsurgery in an "integrative omics" strategy combining proteomics, transcriptomics, genomics and interactomics data. This approach identified a set of proteins preferentially secreted by Sertoli cells or germ cells. An interaction network analysis revealed complex, interlaced cell-cell dialog between the secretome and membranome of seminiferous cells, mediated via the TF. We then focused on germ cell-secreted candidate proteins, and we identified several potential interacting partners located on the surface of Sertoli cells. Two interactions, APOH/CDC42 and APP/NGFR, were validated in situ, in a proximity ligation assay (PLA). Our results provide new insight into the crosstalk between germ cells and Sertoli cells occurring during spermatogenesis. Our findings also demonstrate that this "integrative omics" strategy is powerful enough for data mining and highlighting meaningful cell-cell communication events between different types of cells in a complex tissue, via a biological fluid. This integrative strategy could be applied more widely, to gain access to secretomes that have proved difficult to study whilst avoiding the limitations of in vitro culture. PMID:25111155

Chalmel, Frédéric; Com, Emmanuelle; Lavigne, Régis; Hernio, Nolwen; Teixeira-Gomes, Ana-Paula; Dacheux, Jean-Louis; Pineau, Charles

2014-01-01

284

Parabrachio-cortical connections with the lateral hemisphere in the madagascan hedgehog tenrec: prominent projections to layer 1, weak projections from layer 6  

Microsoft Academic Search

The present study was undertaken to further characterize and subdivide the rhinal cortex (insular and perirhinal areas) in the hedgehog tenrec (Echinops telfairi), a placental mammal with a rather low encephalisation index. Injections of wheat germ agglutinin-horseradish peroxidase into the dorsolateral pontine tegmentum revealed a prominent layer 1 projection to several rhinal target areas, while the rhinal cortex only stained

Heinz Künzle; Susanne Radtke-Schuller; Boris von Stebut

2002-01-01

285

Bioinformatic analysis of P granule-related proteins: insights into germ granule evolution in nematodes  

Microsoft Academic Search

Germ cells in many animals possess a specialized cytoplasm in the form of granules that contain RNA and protein complexes\\u000a essential for the function and preservation of the germline. The mechanism for the formation of these granules is still poorly\\u000a understood; however, the lack of conservation in their components across different species suggests evolutionary convergence\\u000a in the assembly process. Germ

Luis A. Bezares-Calderón; Arturo Becerra; Laura S. Salinas; Ernesto Maldonado; Rosa E. Navarro

2010-01-01

286

Detection of antibodies to Candida albicans germ tube in the diagnosis of systemic candidiasis  

Microsoft Academic Search

Sera from 109 subjects were tested for the presence oftantiCandida albicansantibodies by an indirect immunofluorescence assay. Aliquots of the sera were adsorbed with heat-killed blastospores to remove the antibodies against the surface of the yeast-phase cell wall and tested for anti-germ tube cell wall antibodies. Unadsorbed sera stained the entire cell wall of yeast and germ-tubes. Immunoglobulin G (IgG) antibodies

G. Quindós; J. Pontón; R. Cisterna

1987-01-01

287

Sequence variability in three wheat germ agglutinin isolectins: Products of multiple genes in polyploid wheat  

Microsoft Academic Search

Summary Three highly homologous wheat germ isolectins (95–97%) are distinct gene products in hexaploid wheat. The amino acid sequences of two of these [wheat germ agglutinin 1 (WGA1) and 2 (WGA2)] are compared with sequence date derived from a complementary DNA (cDNA) clone for the third isolection (WGA3). This comparison includes three corrections to earlier amino acid sequences data of

Christine S. Wright; Natasha Raikhel

1989-01-01

288

Localisation of RNAs into the Germ Plasm of Vitellogenic Xenopus Oocytes  

PubMed Central

We have studied the localisation of mRNAs in full-grown Xenopus laevis oocytes by injecting fluorescent RNAs, followed by confocal microscopy of the oocyte cortex. Concentrating on RNA encoding the Xenopus Nanos homologue, nanos1 (formerly Xcat2), we find that it consistently localised into aggregated germ plasm ribonucleoprotein (RNP) particles, independently of cytoskeletal integrity. This implies that a diffusion/entrapment-mediated mechanism is active, as previously reported for previtellogenic oocytes. Sometimes this was accompanied by localisation into scattered particles of the “late”, Vg1/VegT pathway; occasionally only late pathway localisation was seen. The Xpat RNA behaved in an identical fashion and for neither RNA was the localisation changed by any culture conditions tested. The identity of the labelled RNP aggregates as definitive germ plasm was confirmed by their inclusion of abundant mitochondria and co-localisation with the germ plasm protein Hermes. Further, the nanos1/Hermes RNP particles are interspersed with those containing the germ plasm protein Xpat. These aggregates may be followed into the germ plasm of unfertilized eggs, but with a notable reduction in its quantity, both in terms of injected molecules and endogenous structures. Our results conflict with previous reports that there is no RNA localisation in large oocytes, and that during mid-oogenesis even germ plasm RNAs localise exclusively by the late pathway. We find that in mid oogenesis nanos1 RNA also localises to germ plasm but also by the late pathway. Late pathway RNAs, Vg1 and VegT, also may localise into germ plasm. Our results support the view that mechanistically the two modes of localisation are extremely similar, and that in an injection experiment RNAs might utilise either pathway, the distinction in fates being very subtle and subject to variation. We discuss these results in relation to their biological significance and the results of others. PMID:23626739

Nijjar, Sarbjit; Woodland, Hugh R.

2013-01-01

289

No extension of lifespan by ablation of germ line in Drosophila  

PubMed Central

Increased reproduction is frequently associated with a reduction in longevity in a variety of organisms. Traditional explanations of this ‘cost of reproduction’ suggest that trade-offs between reproduction and longevity should be obligate. However, it is possible to uncouple the two traits in model organisms. Recently, it has been suggested that reproduction and longevity are linked by molecular signals produced by specific reproductive tissues. For example, in Caenorhabditis elegans, lifespan is extended in worms that lack a proliferating germ line, but which possess somatic gonad tissue, suggesting that these tissues are the sources of signals that mediate lifespan. In this study, we tested for evidence of such gonadal signals in Drosophila melanogaster. We ablated the germ line using two maternal effect mutations: germ cell-less and tudor. Both mutations result in flies that lack a proliferating germ line but that possess a somatic gonad. In contrast to the findings from C. elegans, we found that germ line ablated females had reduced longevity relative to controls and that the removal of the germ line led to an over-proliferation of the somatic stem cells in the germarium. Our results contrast with the widely held view that it is downstream reproductive processes such as the production and/or laying of eggs that are costly to females. In males, germ line ablation caused either no difference, or a slight extension, in longevity relative to controls. Our results indicate that early acting, upstream reproductive enabling processes are likely to be important in determining reproductive costs. In addition, we suggest that the specific roles and putative patterns of molecular signalling in the germ line and somatic tissues are not conserved between flies and worms. PMID:16627279

Barnes, Andrew I; Boone, James M; Jacobson, Jake; Partridge, Linda; Chapman, Tracey

2005-01-01

290

MicroRNA Biogenesis Is Required for Mouse Primordial Germ Cell Development and Spermatogenesis  

Microsoft Academic Search

Background: MicroRNAs (miRNAs) are critical regulators of transcriptional and post-transcriptional gene silencing, which are involved in multiple developmental processes in many organisms. Apart from miRNAs, mouse germ cells express another type of small RNA, piwi-interacting RNAs (piRNAs). Although it has been clear that piRNAs play a role in repression of retrotransposons during spermatogenesis, the function of miRNA in mouse germ

Katsuhiko Hayashi; Masahiro Kaneda; Fuchou Tang; Petra Hajkova; Kaiqin Lao; Donal O'Carroll; Partha P. Das; Alexander Tarakhovsky; Eric A. Miska; M. Azim Surani

2008-01-01

291

Rearing rats in a germ-free environment eliminates their odors of individuality  

Microsoft Academic Search

In order to test the hypothesis that commensal bacteria influence the urinary odors of individuality, we collected urine from PVG and PVG.R1 male rats born by cesarian section and reared in a germ-free environment. Using the habituation-dishabituation test with PVG.RT1u and Lister hooded rats as subjects, we found that urine from the germ-free rats was not discriminated, while urine from

Prim B. Singh; Jeff Herbert; Bruce Roser; Lindsey Arnott; David K. Tucker; Richard E. Brown

1990-01-01

292

Apoptosis mediated by phosphatidylserine externalization in the elimination of aneuploid germ cells during human spermatogenesis.  

PubMed

It has been described that aneuploidies trigger cell cycle checkpoints leading to apoptosis. The aim of this study was to assess the relationship between the presence of chromosomal abnormalities and apoptosis in germ cells and in Sertoli cells. Fourteen diagnostic testicular biopsies from infertile patients were processed following a sequential methodology, which included enzymatic disaggregation, apoptotic staining, cell sorting, cell fixation, and fluorescent in situ hybridization analysis. The chromosome constitution of germ cells (interphase pre-meiotic germ cells, meiotic figures, post-reductional germ cells, and spermatozoa) and Sertoli cells was evaluated in non-sorted and flow-sorted cell populations (apoptotic and viable). The mean percentage of aneuploidy was compared between the three fractions in each cell type using a Kruskal-Wallis test. If significant results were obtained, a two-by-two Chi-squared test was performed. There were significant differences between the apoptotic fraction and the viable and non-sorted fractions in the pre-meiotic germ cells (p < 0.01). In the remaining cell types, no association between the presence of aneuploidy and apoptotic processes was observed, even in the case of post-reductional germ cells in which we detected the highest rates of aneuploidy regardless of the fraction analyzed. From our data, it can be inferred that most of the aneuploid post-reductional germ cells are efficiently removed from the testicular epithelium without differentiating into spermatozoa. Our results suggest that the elimination of aneuploid testicular epithelial cells is triggered by different mechanisms. Accordingly, the cellular elimination of aneuploid germ cells beyond the blood-testis barrier does not involve phosphatidylserine externalization. PMID:25213174

Garcia-Quevedo, L; Blanco, J; Sarrate, Z; Vidal, F

2014-11-01

293

Mechanism of fluid and electrolyte secretion in the germ-free rat cecum  

Microsoft Academic Search

The cecum of the germ-free rat is filled with a large volume of liquid: cecum plus cecal contents comprise up to 25% of the rodent's body weight. To explain the presence of the liquid cecal contents in the germ-free rat, cecal transport of water and electrolytes was studied using a closed-loop technique with [14C]polyethylene glycol as a nonabsorbable marker. When

Mark Donowitz; Henry J. Binder

1979-01-01

294

Stem cell factor and c-Kit in human primordial germ cells and fetal ovaries  

Microsoft Academic Search

The distribution of the tyrosine kinase receptor c-Kit and its ligand stem cell factor (SCF) was evaluated by immunohistochemistry in primordial germ cells (PGCs) and human embryonic gonads during weeks 5–8 of prenatal life, and fetal ovaries during weeks 9–36 of prenatal life. Distinct c-Kit and SCF staining was present in primordial germ cells in the wall of the hindgut

Poul Erik Høyer; Anne Grete Byskov; Kjeld Møllgård

2005-01-01

295

Differentiating germ cells can revert into functional stem cells in Drosophila melanogaster ovaries  

Microsoft Academic Search

Many tissues including blood, skin, gut and germ cells are continuously maintained by tissue stem cells. Under certain conditions, however, other organs can undergo repair using stem-cell-like progenitors generated by cell de-differentiation. Cell fates have been broadened experimentally, but mechanisms allowing de-differentiation to a stem cell state are poorly known. Germline stem cells begin to differentiate by forming interconnected germ

Toshie Kai; Allan Spradling

2004-01-01

296

Syphilis - primary  

MedlinePLUS

Primary syphilis; Secondary syphilis; Late syphilis; Tertiary syphilis ... Syphilis is a sexually transmitted, infectious disease caused by the spirochete Treponema pallidum . This bacterium causes infection ...

297

Chromosome X modulates incidence of testicular germ cell tumors in Ter mice  

PubMed Central

Germ cell tumor development in humans has been proposed to be part of testicular dysgenesis syndrome (TDS), which manifests as undescended testes, sterility, hypospadias, and, in extreme cases, as germ cell tumors. Males of the Ter mouse strain show interesting parallels to TDS because they either lack germ cells and are sterile or develop testicular germ cell tumors. We found that these defects in Ter mice are due to mutational inactivation of the Dead-end (Dnd1) gene. Here we report that chromo-some X modulates germ cell tumor development in Ter mice. We tested whether the X or the Y chromosome influences tumor incidence. We used chromosome substitution strains to generate two new mouse strains: 129-Ter/Ter that carry either a C57BL/6J (B6)-derived chromosome (Chr) X or Y. We found that Ter/Ter males with B6-Chr X, but not B6-Chr Y, showed a significant shift in propensity from testicular tumor development to sterile testes pheno-type. Thus, our studies provide unambiguous evidence that genetic factors from Chr X modulate the incidence of germ cell tumors in mice with inactivated Dnd1. PMID:18049836

Hammond, Shirley; Zhu, Rui; Matin, Angabin; Youngren, Kirsten K.; Lam, Josephine; Anderson, Philip

2009-01-01

298

Malignant mixed germ cell tumour of ovary- an unusual combination and review of literature.  

PubMed

Mixed germ cell tumours of the ovary are malignant neoplasms of the ovary comprising of two or more types of germ cell components. Most of the malignant mixed germ cell tumours consists of dysgerminoma accompanied by endodermal sinus tumours, immature teratoma or choriocarcinoma. There are only few case reports of mixed germ cell tumours with different combinations of malignant components.We report a very rare case of mixed germ cell tumours consisted of malignant components of endodermal sinus tumour, emryonal carcinoma, and benign component of teratomatuos and trophoblastic differentiation. This is the first case report in the literature with both benign and malignant component of type described to best of our knowledge.Patient was an 18 year old girl, who presented with pain abdomen, abdominal mass and irregular bleeding. Ultrasound and CT scan showed a huge mass with solid and cystic component. Tumour markers i.e alpha feto- protein (AFP), human chorionic gonadotropin (hCG), lactate dehydrogenate (LDH) and Ca-125 were raised. We performed fertility sparing surgery by preserving one ovary, tube and uterus.ConclusionMalingnant mixed germ cell tumours of ovary are highly aggressive neoplasm and early intervention and fertility sparing surgery is required for any adolescent girl presenting with rapidly enlarging pelvic mass. PMID:25366470

Goyal, Lajya; Kaur, Sharanjit; Kawatra, Kanwardeep

2014-11-01

299

Distinct chromatin organization in the germ line founder cell of the Caenorhabditis elegans embryo.  

PubMed

Cells belonging to the germ lineage segregate physically and molecularly from their somatic neighbors during embryogenesis. While germ line-specific chromatin modifications have been identified at later stages in the Caenorhabditis elegans nematode, none have been found in the single P4 germ line founder cell that arises at the beginning of gastrulation. Using light and electron microscopy, we now report that the chromatin organization in the germ line founder cell of the early C. elegans embryo is distinct from that in the neighboring somatic cells. This unique organization is characterized by a greater chromatin compaction and an expansion of the interchromatin compartment. The ultrastructure of individual chromatin domains does not differ between germ line and somatic cells, pointing to a specific organization mainly at the level of the whole nucleus. We show that this higher order reorganization of chromatin is not a consequence of the P4 nucleus being smaller than somatic nuclei or having initiated mitosis. Imaging of living embryos expressing fluorescent markers for both chromatin and P granules revealed that the appearance of a distinct chromatin organization in the P4 cell occurs approximately 10 min after its birth and coincides with the aggregation of P granules around the nucleus, suggesting a possible link between these two events. The higher order reorganization of chromatin that is reported here occurs during the establishment of definitive germ cell identity. The changes we have observed could therefore be a prerequisite for the programming of chromatin totipotency. PMID:25279455

Vágnerová, Lenka; Gombitová, Adriána; Cmarko, Dušan; Lanctôt, Christian

2014-12-01

300

Germ cells of the centipede Strigamia maritima are specified early in embryonic development.  

PubMed

We provide the first systematic description of germ cell development with molecular markers in a myriapod, the centipede Strigamia maritima. By examining the expression of Strigamia vasa and nanos orthologues, we find that the primordial germ cells are specified from at least the blastoderm stage. This is a much earlier embryonic stage than previously described for centipedes, or any other member of the Myriapoda. Using these genes as markers, and taking advantage of the developmental synchrony of Strigamia embryos within single clutches, we are able to track the development of the germ cells throughout embryogenesis. We find that the germ cells accumulate at the blastopore; that the cells do not internalize through the hindgut, but rather through the closing blastopore; and that the cells undergo a long-range migration to the embryonic gonad. This is the first evidence for primordial germ cells displaying these behaviours in any myriapod. The myriapods are a phylogenetically important group in the arthropod radiation for which relatively little developmental data is currently available. Our study provides valuable comparative data that complements the growing number of studies in insects, crustaceans and chelicerates, and is important for the correct reconstruction of ancestral states and a fuller understanding of how germ cell development has evolved in different arthropod lineages. PMID:24930702

Green, Jack E; Akam, Michael

2014-08-15

301

Germ cells of the centipede Strigamia maritima are specified early in embryonic development  

PubMed Central

We provide the first systematic description of germ cell development with molecular markers in a myriapod, the centipede Strigamia maritima. By examining the expression of Strigamia vasa and nanos orthologues, we find that the primordial germ cells are specified from at least the blastoderm stage. This is a much earlier embryonic stage than previously described for centipedes, or any other member of the Myriapoda. Using these genes as markers, and taking advantage of the developmental synchrony of Strigamia embryos within single clutches, we are able to track the development of the germ cells throughout embryogenesis. We find that the germ cells accumulate at the blastopore; that the cells do not internalize through the hindgut, but rather through the closing blastopore; and that the cells undergo a long-range migration to the embryonic gonad. This is the first evidence for primordial germ cells displaying these behaviours in any myriapod. The myriapods are a phylogenetically important group in the arthropod radiation for which relatively little developmental data is currently available. Our study provides valuable comparative data that complements the growing number of studies in insects, crustaceans and chelicerates, and is important for the correct reconstruction of ancestral states and a fuller understanding of how germ cell development has evolved in different arthropod lineages. PMID:24930702

Green, Jack E.; Akam, Michael

2014-01-01

302

Germ cell transplantation as a potential biotechnological approach to fish reproduction.  

PubMed

Although the use of germ cell transplantation has been relatively well established in mammals, the technique has only been adapted for use in fish after entering the 2000s. During the last decade, several different approaches have been developed for germ cell transplantation in fish using recipients of various ages and life stages, such as blastula-stage embryos, newly hatched larvae and sexually mature specimens. As germ cells can develop into live organisms through maturation and fertilization processes, germ cell transplantation in fish has opened up new avenues of research in reproductive biotechnology and aquaculture. For instance, the use of xenotransplantation in fish has lead to advances in the conservation of endangered species and the production of commercially valuable fish using surrogated recipients. Further, this could also facilitate the engineering of transgenic fish. However, as is the case with mammals, knowledge regarding the basic biology and physiology of germline stem cells in fish remains incomplete, imposing a considerable limitation on the application of germ cell transplantation in fish. Furthering our understanding of germline stem cells would contribute significantly to advances regarding germ cell transplantation in fish. PMID:22290474

Lacerda, S M S N; Costa, G M J; Campos-Junior, P H A; Segatelli, T M; Yazawa, R; Takeuchi, Y; Morita, T; Yoshizaki, G; França, L R

2013-02-01

303

Clinical and genetic aspects of testicular germ cell tumours  

PubMed Central

In this paper we review clinical and genetic aspects of testicular germ cell tumours (TGCTs). TGCT is the most common type of malignant disorder in men aged 15-40 years. Its incidence has increased sharply in recent years. Fortunately, survival of patients with TGCT has improved enormously, which can chiefly be attributed to the cisplatin-based polychemotherapy that was introduced in the nineteen eighties to treat patients with metastasized TGCT. In addition, new strategies have been developed in the surgical approach to metastasized/non-metastasized TGCT and alterations have been made to the radiotherapy technique and radiation dose for seminoma. Family history of TGCT is among the strongest risk factors for this tumour type. Although this fact and others suggest the existence of genetic predisposition to develop TGCT, no germline mutations conferring high risk of developing TGCT have been identified so far. A small deletion, referred to as gr/gr, identified on the Y chromosome is probably associated with only a modest increase in TGCT risk, and linkage of familial TGCT to the Xq27 region has not been confirmed yet. Whether highly penetrant TGCT-predisposing mutations truly exist or familial clustering of TGCT can be explained by combinations of weak predispositions, shared in utero or postnatal risks factors and coincidental somatic mutations is an intriguing puzzle, still waiting to be solved. PMID:19715611

Holzik, Martijn F Lutke; Sijmons, Rolf H; Hoekstra-Weebers, Josette EHM; Sleijfer, Dirk T; Hoekstra, Harald J

2008-01-01

304

NANOG priming before full reprogramming may generate germ cell tumours.  

PubMed

Reprogramming somatic cells into a pluripotent state brings patient-tailored, ethical controversy-free cellular therapy closer to reality. However, stem cells and cancer cells share many common characteristics; therefore, it is crucial to be able to discriminate between them. We generated two induced pluripotent stem cell (iPSC) lines, with NANOG pre-transduction followed by OCT3/4, SOX2, and LIN28 overexpression. One of the cell lines, CHiPS W, showed normal pluripotent stem cell characteristics, while the other, CHiPS A, though expressing pluripotency markers, failed to differentiate and gave rise to germ cell-like tumours in vivo. Comparative genomic hybridisation analysis of the generated iPS lines revealed that they were genetically more stable than human embryonic stem cell counterparts. This analysis proved to be predictive for the differentiation potential of analysed cells. Moreover, the CHiPS A line expressed a lower ratio of p53/p21 when compared to CHiPS W. NANOG pre-induction followed by OCT3/4, SOX2, MYC, and KLF4 induction resulted in the same tumour-inducing phenotype. These results underline the importance of a re-examination of the role of NANOG during reprogramming. Moreover, this reprogramming method may provide insights into primordial cell tumour formation and cancer stem cell transformation. PMID:22071697

Grad, I; Hibaoui, Y; Jaconi, M; Chicha, L; Bergström-Tengzelius, R; Sailani, M R; Pelte, M F; Dahoun, S; Mitsiadis, T A; Töhönen, V; Bouillaguet, S; Antonarakis, S E; Kere, J; Zucchelli, M; Hovatta, O; Feki, A

2011-01-01

305

Bmi1 expression in long-term germ stem cells  

PubMed Central

Asingle cells in undifferentiated spermatogonia are considered to be the most primitive forms of germ stem cells (GSCs). Although GFR?1 is thought to be a marker of Asingle cells, we found that Bmi1High is more specific than GFR?1 for Asingle cells. Bmi1High expression in Asingle cells is correlated with seminiferous stages, and its expression was followed by the proliferative stage of Asingle GSCs. In contrast, GFR?1 expression was seminiferous stage-independent. Fate analyses of EdU-positive Bmi1High-positive cell-derived Asingle cells revealed that these cells self-renewed or generated transient amplifying Apaired cells. Bmi1High-positive cells were resistant to irradiation-induced injury, after which they regenerated. Elimination of Bmi1High-positive cells from seminiferous tubules resulted in the appearance of tubules with seminiferous stage mismatches. Thus, in this study, we found that Bmi1High is a seminiferous stage-dependent marker for long-term GSCs and that Bmi1High-positive cells play important roles in maintaining GSCs and in regenerating spermatogenic progenitors after injury. PMID:25146451

Komai, Yoshihiro; Tanaka, Toshihiro; Tokuyama, Yoko; Yanai, Hirotsugu; Ohe, Shuichi; Omachi, Taichi; Atsumi, Naho; Yoshida, Naoko; Kumano, Keiki; Hisha, Hiroko; Matsuda, Tadashi; Ueno, Hiroo

2014-01-01

306

Morphometric Approach to Pulp Fibroblast Development in Tooth Germ  

PubMed Central

This paper builds a morphometric framework for the analysis of dental pulp fibroblast evolution during tooth development. We investigated 15 tooth germs (cases) organized, by histological criteria, in three groups corresponding to cap, early bell, and late bell stages, respectively. Each group comprised five cases. The morphometric description used the following parameters: area (A), perimeter (P)—automatically extracted by a color segmentation technique, and form factor (FF)—calculated as 4?A/P2. The designed framework operated at inter- and intragroup levels. The intergroup analysis quantified the differences between groups, in the sense of a relative distance (RD) adequately defined by mean-value scaling. We showed that the stage of early bell is approximately 5 times closer to late bell than to cap. The quantification procedure required concomitant information about A, P parameters (as P versus A dependences, or FF values), whereas the procedure failed for A or P separately used. The intragroup analysis quantified the similarity of the cases belonging to the same stage. We proved that, unlike the intergroup tests, the individual exploitation of all three descriptors A, P, and FF is effective, yielding highly compatible results. Within any group, most cases presented RDs less than 10% from the group mean value, regardless of the descriptor type. PMID:25057501

C?runtu, Irina-Draga; S?vinescu, Sergiu Daniel; Am?linei, Cornelia

2014-01-01

307

Familial testicular germ cell tumor: no associated syndromic pattern identified  

PubMed Central

Background Testicular germ cell tumor (TGCT) is the most common malignancy in young men. Familial clustering, epidemiologic evidence of increased risk with family or personal history, and the association of TGCT with genitourinary (GU) tract anomalies have suggested an underlying genetic predisposition. Linkage data have not identified a rare, highly-penetrant, single gene in familial TGCT (FTGCT) cases. Based on its association with congenital GU tract anomalies and suggestions that there is an intrauterine origin to TGCT, we hypothesized the existence of unrecognized dysmorphic features in FTGCT. Methods We evaluated 38 FTGCT individuals and 41 first-degree relatives from 22 multiple-case families with detailed dysmorphology examinations, physician-based medical history and physical examination, laboratory testing, and genitourinary imaging studies. Results The prevalence of major abnormalities and minor variants did not significantly differ between either FTGCT individuals or their first-degree relatives when compared with normal population controls, except for tall stature, macrocephaly, flat midface, and retro-/micrognathia. However, these four traits were not manifest as a constellation of features in any one individual or family. We did detect an excess prevalence of the genitourinary anomalies cryptorchidism and congenital inguinal hernia in our population, as previously described in sporadic TGCT, but no congenital renal, retroperitoneal or mediastinal anomalies were detected. Conclusions Overall, our study did not identify a constellation of dysmorphic features in FTGCT individuals, which is consistent with results of genetic studies suggesting that multiple low-penetrance genes are likely responsible for FTGCT susceptibility. PMID:24559313

2014-01-01

308

Pathogen germs response to low-dose radiation — medical approach  

NASA Astrophysics Data System (ADS)

The side effects of radiation therapy in the case of microbial loading of irradiated organs was considered as phenomenological basis of the experiment carried out on Staphylococcus aureus (ATCC germ) exposed to low X-ray doses. The inoculum was prepared in a liquid culture medium with standard composition, the volumes of 3 ml identical samples (in sterile glass tubes) being irradiated in hospital conditions. Five experimental variants were developed corresponding to irradiation time durations between 25 and 100 minutes. The spectro-colorimetric assay was accomplished at 560 nm and 420 nm, the resulting average values (for three repetitions) being analyzed from the viewpoint of cell density in the irradiated variants compared to control ones. The resistance to antibiotics of the irradiated bacteria was tested on agarized cultures against five antibiotic molecules (ampicillin, cloramphenicol, tetracycline, tobramicin and ofloxacin) by assessing the diameter of inhibition growth areas in each case. The increase of the inhibition area diameter with up to 15% (in the case of tetracycline) was noticed for the lowest irradiation time for all five antibiotics, which is suggesting a weakening of the bacteria resistance to the pharmaceutical agents following the X-ray treatment. This was concordant with the results of the spectro-colorimetric assay of the cell density within the directly irradiated bacteria cultures. The main issue of this study is concerning the optimization of the radiotherapy protocol in patients with potential microbial loading.

Poiata, A.; Focea, R.; Creanga, D.

2012-04-01

309

Bmi1 expression in long-term germ stem cells.  

PubMed

Asingle cells in undifferentiated spermatogonia are considered to be the most primitive forms of germ stem cells (GSCs). Although GFR?1 is thought to be a marker of Asingle cells, we found that Bmi1(High) is more specific than GFR?1 for Asingle cells. Bmi1(High) expression in Asingle cells is correlated with seminiferous stages, and its expression was followed by the proliferative stage of Asingle GSCs. In contrast, GFR?1 expression was seminiferous stage-independent. Fate analyses of EdU-positive Bmi1(High)-positive cell-derived Asingle cells revealed that these cells self-renewed or generated transient amplifying Apaired cells. Bmi1(High)-positive cells were resistant to irradiation-induced injury, after which they regenerated. Elimination of Bmi1(High)-positive cells from seminiferous tubules resulted in the appearance of tubules with seminiferous stage mismatches. Thus, in this study, we found that Bmi1(High) is a seminiferous stage-dependent marker for long-term GSCs and that Bmi1(High)-positive cells play important roles in maintaining GSCs and in regenerating spermatogenic progenitors after injury. PMID:25146451

Komai, Yoshihiro; Tanaka, Toshihiro; Tokuyama, Yoko; Yanai, Hirotsugu; Ohe, Shuichi; Omachi, Taichi; Atsumi, Naho; Yoshida, Naoko; Kumano, Keiki; Hisha, Hiroko; Matsuda, Tadashi; Ueno, Hiroo

2014-01-01

310

Germ-cell tumors in childhood and adolescence  

Microsoft Academic Search

Summary In mature and immature teratoma the treatment is surgical. The risk of recurrence can be estimated from the parameters primary site (with the coccygeal tumors being most at risk), histological grade of immaturity and completeness of the primary resection including the adjacent organ of origin (coccyx, ovary, testis etc.). In case of a microscopically com- plete tumor resection there

U. Gobel; D. T. Schneider; G. Calaminus; R. J. Haas; P. Schmidt; D. Harms

311

Fat absorption in germ-free and conventional rats artificially deprived of bile secretion.  

PubMed Central

Bile duct ligation was performed in germ-free and conventional rats in order to study the effects of bile deprivation on the absorption of dietary lipids and the excretion of faecal lipids in the presence or the absence of gastrointestinal flora. The main consequence of bile duct ligation in conventional rats was decrease of about 50% in the apparent absorption of dietary lipids (peanut oil). In germ-free rats, absorption decreased by only about 25%.In conventional as well as in germ-free controls, faecal lipids were mainly excreted as compounds directly soluble in organic solvents that is, free fatty acids, triglycerides, partial glycerides, cholesterol, cholesterol esters. Deprivation of bile secretion significantly increased the faecal excretion of 'insoluble' compounds-that is, calcium soaps-both in germ-free and conventional rats. Free fatty acids and sterol esters were the two main class of soluble faecal lipids both in germ-free and conventional rats deprived of bile secretion. Faecal excretion of triglycerides remained low in germ-free as well as in conventional animals. No significant difference of fatty acid absorption was observed between germ-free and conventional controls. Deprivation of bile secretion resulted in a significant decrease in the absorption of all fatty acids in germ-free as well as in conventional animals. However, the decrease was larger for saturated fatty acids-that is, 16:0 or 18:0- than for unsaturated fatty acids-that is, 18:1 or 18:2. The absorption of all fatty acids, except linoleic acid (18:2), was significantly lower in conventional rats artificially deprived of bile secretion than in their germ-free counterparts. Evidence was given for a negative digestive balance of stearic acid (18:0) in bile deprived conventional animals. This observation was correlated with a very efficient biohydrogenation of dietary unsaturated fatty acids as revealed by radio gas chromatography of faecal acids in bile deprived conventional rats fed a diet containing 1-14C oleic acid (18:1) as homogeneous triglycerides. Nevertheless, biohydrogenation of unsaturated dietary fatty acids by the gastrointestinal flora was not considered to be the only factor involved in the origin of the difference of fat absorption between bile deprived germ-free and conventional animals. PMID:7056496

Demarne, Y; Corring, T; Pihet, A; Sacquet, E

1982-01-01

312

Production of chicken progeny (Gallus gallus domesticus) from interspecies germline chimeric duck (Anas domesticus) by primordial germ cell transfer.  

PubMed

The present study aimed to investigate the differentiation of chicken (Gallus gallus domesticus) primordial germ cells (PGCs) in duck (Anas domesticus) gonads. Chimeric ducks were produced by transferring chicken PGCs into duck embryos. Transfer of 200 and 400 PGCs resulted in the detection of a total number of 63.0 ± 54.3 and 116.8 ± 47.1 chicken PGCs in the gonads of 7-day-old duck embryos, respectively. The chimeric rate of ducks prior to hatching was 52.9% and 90.9%, respectively. Chicken germ cells were assessed in the gonad of chimeric ducks with chicken-specific DNA probes. Chicken spermatogonia were detected in the seminiferous tubules of duck testis. Chicken oogonia, primitive and primary follicles, and chicken-derived oocytes were also found in the ovaries of chimeric ducks, indicating that chicken PGCs are able to migrate, proliferate, and differentiate in duck ovaries and participate in the progression of duck ovarian folliculogenesis. Chicken DNA was detected using PCR from the semen of chimeric ducks. A total number of 1057 chicken eggs were laid by Barred Rock hens after they were inseminated with chimeric duck semen, of which four chicken offspring hatched and one chicken embryo did not hatch. Female chimeric ducks were inseminated with chicken semen; however, no fertile eggs were obtained. In conclusion, these results demonstrated that chicken PGCs could interact with duck germinal epithelium and complete spermatogenesis and eventually give rise to functional sperm. The PGC-mediated germline chimera technology may provide a novel system for conserving endangered avian species. PMID:22190706

Liu, Chunhai; Khazanehdari, Kamal A; Baskar, Vijaya; Saleem, Shazia; Kinne, Joerg; Wernery, Ulrich; Chang, Il-Kuk

2012-04-01

313

Survival of patients with nonseminomatous germ cell cancer: a review of the IGCC classification by Cox regression and recursive partitioning.  

PubMed

The International Germ Cell Consensus (IGCC) classification identifies good, intermediate and poor prognosis groups among patients with metastatic nonseminomatous germ cell tumours (NSGCT). It uses the risk factors primary site, presence of nonpulmonary visceral metastases and tumour markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and lactic dehydrogenase (LDH). The IGCC classification is easy to use and remember, but lacks flexibility. We aimed to examine the extent of any loss in discrimination within the IGCC classification in comparison with alternative modelling by formal weighing of the risk factors. We analysed survival of 3048 NSGCT patients with Cox regression and recursive partitioning for alternative classifications. Good, intermediate and poor prognosis groups were based on predicted 5-year survival. Classifications were further refined by subgrouping within the poor prognosis group. Performance was measured primarily by a bootstrap corrected c-statistic to indicate discriminative ability for future patients. The weights of the risk factors in the alternative classifications differed slightly from the implicit weights in the IGCC classification. Discriminative ability, however, did not increase clearly (IGCC classification, c=0.732; Cox classification, c=0.730; Recursive partitioning classification, c=0.709). Three subgroups could be identified within the poor prognosis groups, resulting in classifications with five prognostic groups and slightly better discriminative ability (c=0.740). In conclusion, the IGCC classification in three prognostic groups is largely supported by Cox regression and recursive partitioning. Cox regression was the most promising tool to define a more refined classification. British Journal of Cancer (2004) 90, 1176-1183. doi:10.1038/sj.bjc.6601665 www.bjcancer.com Published online 24 February 2004 PMID:15026798

van Dijk, M R; Steyerberg, E W; Stenning, S P; Dusseldorp, E; Habbema, J D F

2004-03-22

314

Global deletion of Trp53 reverts ovarian tumor phenotype of the germ cell-deficient white spotting variant (wv) mice.  

PubMed

White spotting variant (Wv) mice are spontaneous mutants attributed to a point mutation in the c-Kit gene, which reduces the tyrosine kinase activity to around 1% and affects the development of melanocytes, mast cells, and germ cells. Homozygous mutant mice are sterile but can live nearly a normal life span. The female Wv mice have a greatly reduced ovarian germ cell and follicle reserve at birth, and the remaining follicles are largely depleted soon after the females reach reproductive stage at around 7 weeks of age. Consequently, ovarian epithelial tumors develop in 100% of Wv females by 3 to 4 months of age. These tumors, called tubular adenomas, are benign but can become invasive in older Wv mice. We tested if additional genetic mutation(s) could convert the benign ovarian epithelial tumors to malignant tumors by crossing the Wv mutant into the Trp53 knockout background. Surprisingly, we found that global deletion of Trp53 suppressed the development of ovarian tubular adenomas in Wv mice. The ovaries of Wv/Wv; Trp53 (-/-) mice were covered by a single layer of surface epithelium and lacked excessive epithelial proliferation. Rather, the ovaries contained a small number of follicles. The presence of ovarian follicles and granulosa cells, as indicated by Pgc7 and inhibin-alpha expression, correlated with the absence of epithelial lesions. A reduction of Pten gene dosage, as in Wv/Wv; Pten (+/-) mice, produced a similar, though less dramatic, phenotype. We conclude that deletion of Trp53 prolongs the survival of ovarian follicles in Wv mice and consequently prevents the proliferation of ovarian epithelial cells and development of ovarian tubular adenomas. The results suggest that various cell types within the ovary communicate and mutually modulate, and an intact tissue environment is required to ensure homeostasis of ovarian surface epithelial cells. Especially, the current finding emphasizes the importance of ovarian follicles in suppressing the hyperplastic growth of ovarian epithelial cells, dominating over the loss of p53. PMID:25622902

Cai, Kathy Qi; Wang, Ying; Smith, Elizabeth R; Smedberg, Jennifer L; Yang, Dong-Hua; Yang, Wan-Lin; Xu, Xiang-Xi

2015-01-01

315

Expression and function of the vitamin D receptor in malignant germ cell tumour of the testis.  

PubMed

Testicular germ cell tumours (TGCTs) are the most common malignancy in young men aged 18-35 years. They are clinically and histologically subdivided into seminomas and non-seminomas. 1,25-Dihydroxyvitamin D (1,25(OH)(2)D(3)) is the active form of vitamin D and exerts its actions via a specific intracellular vitamin D receptor (VDR). Several investigations in the recent years have revealed, in addition to a physiological occurrence of the VDR in various tissues, VDR expression in different human malignancies. Furthermore, 1,25(OH)(2)D(3) plays an important role in the regulation of cell proliferation and differentiation. In different normal and malignant cell types, antiproliferative and pro-differentiating effects of 1,25(OH)(2)D(3) are described. We investigated whether TGCT express the VDR, wether differences exist between the histological subtypes and if vitamin D has a function on the proliferation of tumour cells. Furthermore, we investigated the potential function of the vitamin D-regulated genes nuclear receptor co-repressor 1(NCOR1), nuclear receptor co-repressor 2 (NCOR2), thyroid receptor interacting protein 15 (TRIP15), Growth Arrest and DNA Damage (GADD45), MAP kinase-activated protein kinase 2 (MAPKAPK2), Cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) and Cytochrome P450, family 27, subfamily B, polypeptide 1 (CYP27B1) in the pathogenesis of TGCT. We demonstrate, for the first time, that primary TGCT as well as TGCT cell lines, express VDR mRNA and protein. Vitamin D and VDR may play a role in the pathogenesis of TGCTs. Furthermore, vitamin D inhibits proliferation of TGCT cell-lines, potentially via an increase in expression of GADD45. Our data suggest that vitamin D could play a role in antitumour therapy. PMID:22213325

Bremmer, F; Thelen, P; Pottek, T; Behnes, C L; Radzun, H J; Schweyer, S

2012-01-01

316

In vitro differentiation of human tooth germ stem cells into endothelial- and epithelial-like cells.  

PubMed

Current clinical techniques in dental practice include stem cell and tissue engineering applications. Dental stem cells are promising primary cell source for mainly tooth tissue engineering. Interaction of mesenchymal stem cell with epithelial and endothelial cells is strictly required for an intact tooth morphogenesis. Therefore, it is important to investigate whether human tooth germ stem cells (hTGSCs) derived from wisdom tooth are suitable for endothelial and epithelial cell transformation in dental tissue regeneration approaches. Differentiation into endothelial and epithelial cell lineages were mimicked under defined conditions, confirmed by real time PCR, western blotting and immunocytochemical analysis by qualitative and quantitative methods. HUVECs and HaCaT cells were used as positive controls for the endothelial and epithelial differentiation assays, respectively. Immunocytochemical and western blotting analysis revealed that terminally differentiated cells expressed cell-lineage markers including CD31, VEGFR2, VE-Cadherin, vWF (endothelial cell markers), and cytokeratin (CK)-17, CK-19, EpCaM, vimentin (epithelial cell markers) in significant levels with respect to undifferentiated control cells. Moreover, high expression levels of VEGFR1, VEGFR2, VEGF, CK-18, and CK-19 genes were detected in differentiated endothelial and epithelial-like cells. Endothelial-like cells derived from hTGSCs were cultured on Matrigel, tube-like structure formations were followed as an indication for functional endothelial differentiation. hTGSCs successfully differentiate into various cell types with a broad range of functional abilities using an in vitro approach. These findings suggest that hTGSCs may serve a potential stem cell source for tissue engineering and cell therapy of epithelial and endothelial tissue. PMID:25077982

Do?an, Ay?egül; Demirci, Selami; ?ahin, Fikrettin

2015-01-01

317

Time series analysis supporting the hypothesis that enhanced cosmic radiation during germ cell formation can increase breast cancer mortality in germ cell cohorts  

NASA Astrophysics Data System (ADS)

Techniques from cancer epidemiology and time series analysis were used to explore the hypothesis that cosmic radiation can induce germ cell changes leading to increases in future breast cancer mortality. A birth cohort time series for female breast cancer mortality was obtained using a model-independent, age-period-cohort analysis on age-specific mortality data for 1940-1990. The birth cohort series contained several oscillatory components, which were isolated and compared to the corresponding frequency components of a cosmic ray surrogate time series - Greenland ice-core 10Be concentrations. A technique, referred to as component wave-train alignment, was used to show that the breast cancer and cosmic ray oscillations were phase-locked approx. 25 years before the time of birth. This is consistent with the time of germ cell formation, which occurs during the fetal development stage of the preceding generation. Evidence is presented that the observable oscillations in the birth cohort series were residues of oscillations of much larger amplitude in the germ cell cohort, which were attenuated by the effect of the broad maternal age distribution. It is predicted that a minimum of 50% of breast cancer risk is associated with germ cell damage by cosmic radiation (priming event), which leads to the development of individuals with a higher risk of breast cancer. It is proposed that the priming event, by preceding other steps of carcinogenesis, works in concert with risk factor exposure during life. The priming event is consistent with epigenetic changes such as imprinting.

Juckett, D. A.; Rosenberg, Barnett

318

A Mini-Review of Familial Ovarian Germ Cell Tumors: An Additional Manifestation of the Familial Testicular Germ Cell Tumor Syndrome  

PubMed Central

Introduction While testicular germ cell tumors (TGCTs) are the most common malignancy in young men, germ cell tumors in women are uncommon. Familial clustering, epidemiologic evidence of increased risk with family or personal history of TGCT, and associations with genitourinary tract anomalies suggest an underlying genetic predisposition to TGCT, but traditional linkage studies have yet to identify a highlypenetrant TGCT cancer susceptibility gene. In this paper, we investigate the familial occurrence of testicular and ovarian germ cell tumors. Methods We report a family in which a TGCT and an ovarian germ cell tumor (OGCT) occurred in two siblings, summarize the existing literature on familial occurrences of OGCT, either alone or in combination with extragonadal or TGCTs, and compare the incidence of familial and sporadic testicular and ovarian GCTs. Sporadic GCT data were obtained from the US Surveillance Epidemiology and End Results (SEER) registry. Results We identified 16 reports of OGCT occurring in conjunction with either ovarian, testicular or extragonadal GCT. In these familial cases, the mean age at onset of female dysgerminoma was younger than that noted in the general population (age 17 vs age 24, p=0.01). In SEER, the incidence of TGCT was 15 times higher than that of OGCT. Histologic distributions in males and females showed distinctly different patterns. Discussion Although the incidence of OGCTs in the general population is quite low, its occurrence in multiple members of the same family and in families with TGCT suggests that a gene conferring susceptibility to GCTs may exist in some families. PMID:19679044

Giambartolomei, Claudia; Mueller, Christine M.; Greene, Mark H.; Korde, Larissa A.

2009-01-01

319

Immunofluorescence Visualization of Germ-Line-Specific Cytoplasmic Granules in Embryos, Larvae, and Adults of Caenorhabditis elegans  

Microsoft Academic Search

By using fluorescent antibody staining, we have followed cytoplasmic granules unique to germ-line cells throughout the life cycle of Caenorhabditis elegans. These elements, designated P granules, are segregated exclusively to germ-line precursor cells during early embryogenesis. Prior to mitosis at each of the early cleavages that produce a somatic and germ-line daughter cell, the granules become localized in the region

Susan Strome; William B. Wood

1982-01-01

320

Effect of adding wheat bran and germ fractions on the chemical composition of high-fiber toast bread  

Microsoft Academic Search

The effect of the type of bran, level of addition, particle size and addition of wheat germ on the chemical composition of high-fiber toast bread was investigated. The bran and germ fractions were found to be high in ash, protein, fat and total dietary fiber contents. The wheat germ had a protein content of 27.88% compared with 11.35, 12.69 and

Jiwan S Sidhu; Suad N Al-Hooti; Jameela M Al-Saqer

1999-01-01

321

Mixed germ cell tumor of the testicle with ravdomuosarcomatous component: a case report  

PubMed Central

Introduction Testicular tumors can be classified as seminomatous and non-seminomatous germ-cell tumor (NSGCT) types. Mixed germ cell tumors contain more than one germ cell component and are much more common than any of the pure histologic forms representing 32%-60% of all germ cell tumors. The composition of these tumors varies. Here we present a rare case of a mixed germ cell tumor composed of seminoma, Yolk sack tumor and teratoma containing a sarcoma component of somatic type malignancy. Case presentation A 32-year-old Caucasian male presented with history of right-sided scrotal swelling since 6 months. Backache was present since 2 months and a history of right epididimitis was also present since 8 months. Alpha-Fetoprotein, beta-HCG and LDH values were found abmormal. USG of the scrotum revealed a large right testis swelling characterized by scarce cystic elements and calcifications. CT scan of the abdomen showed nodular metastasis involving the interaortocaval, precaval, and right para-aortic lymph nodes. The block of enlarged lymph nodes infiltrated the psoas muscle. The patient underwent right-sided high orchidectomy and was given chemotherapy of the BEP regimen. After the 2nd cycle the patient discontinued the chemotherapy and when he came for follow-up after a gap of 3 months, despite the normalisation in tumor markers values, the retroperitoneal mass was relapsed. CT scan of the chest showed multiple lung metastases. Conclusion More than 50% of germ-cell tumors include more than 2 basic germ-cell tumor types, with the exception of spermatocytic seminoma. About 90% of the patients with nonseminomatous tumors can achieve complete cure with aggressive chemotherapy and most of them can be cured. Although prognosis of testicular tumors depends largely on clinical stage, histological type and adhesion to the treatment influence the prognosis as well. PMID:20062623

2009-01-01

322

Interaction between DMRT1 function and genetic background modulates signaling and pluripotency to control tumor susceptibility in the fetal germ line.  

PubMed

Dmrt1 (doublesex and mab-3 related transcription factor (1) is a regulator of testis development in vertebrates that has been implicated in testicular germ cell tumors of mouse and human. In the fetal mouse testis Dmrt1 regulates germ cell pluripotency in a strain-dependent manner. Loss of Dmrt1 in 129Sv strain mice results in a >90% incidence of testicular teratomas, tumors consisting cells of multiple germ layers; by contrast, these tumors have never been observed in Dmrt1 mutants of C57BL/6J (B6) or mixed genetic backgrounds. To further investigate the interaction between Dmrt1 and genetic background we compared mRNA expression in wild type and Dmrt1 mutant fetal testes of 129Sv and B6 mice at embryonic day 15.5 (E15.5), prior to overt tumorigenesis. Loss of Dmrt1 caused misexpression of overlapping but distinct sets of mRNAs in the two strains. The mRNAs that were selectively affected included some that changed expression only in one strain or the other and some that changed in both strains but to a greater degree in one versus the other. In particular, loss of Dmrt1 in 129Sv testes caused a more severe failure to silence regulators of pluripotency than in B6 testes. A number of genes misregulated in 129Sv mutant testes also are misregulated in human testicular germ cell tumors (TGCTs), suggesting similar etiology between germ cell tumors in mouse and man. Expression profiling showed that DMRT1 also regulates pluripotency genes in the fetal ovary, although Dmrt1 mutant females do not develop teratomas. Pathway analysis indicated disruption of several signaling pathways in Dmrt1 mutant fetal testes, including Nodal, Notch, and GDNF. We used a Nanos3-cre knock-in allele to perform conditional gene targeting, testing the GDNF coreceptors Gfra1 and Ret for effects on teratoma susceptibility. Conditional deletion of Gfra1 but not Ret in fetal germ cells of animals outcrossed to 129Sv caused a modest but significant elevation in tumor incidence. Despite some variability in genetic background in these crosses, this result is consistent with previous genetic mapping of teratoma susceptibility loci to the region containing Gfra1. Using Nanos3-cre we also uncovered a strong genetic interaction between Dmrt1 and Nanos3, suggesting parallel functions for these two genes in fetal germ cells. Finally, we used chromatin immunoprecipitation (ChIP-seq) analysis to identify a number of potentially direct DMRT1 targets. This analysis suggested that DMRT1 controls pluripotency via transcriptional repression of Esrrb, Nr5a2/Lrh1, and Sox2. Given the strong evidence for involvement of DMRT1 in human TGCT, the downstream genes and pathways identified in this study provide potentially useful candidates for roles in the human disease. PMID:23473982

Krentz, Anthony D; Murphy, Mark W; Zhang, Teng; Sarver, Aaron L; Jain, Sanjay; Griswold, Michael D; Bardwell, Vivian J; Zarkower, David

2013-05-01

323

Characterization of wheat germ protein synthesis initiation factor eIF-4C and comparison of eIF-4C from wheat germ and rabbit reticulocytes.  

PubMed

Eukaryotic protein synthesis initiation factor (eIF)-4C was purified from wheat germ and the molecular weight was calculated to be approximately 19,000 by SDS-polyacrylamide gel electrophoresis. A similar molecular weight was determined by gel filtration chromatography indicating that wheat germ eIF-4C is functional as a single polypeptide chain. An efficient in vitro translation system dependent upon the addition of eIF-4C was developed. This system was used to determine the concentrations of eIF-4C required for the half-maximal rate of translation of satellite tobacco necrosis virus RNA, alfalfa mosaic virus RNA 4, and barley alpha-amylase mRNA. No significant differences in the concentrations of eIF-4C required for the translation of these mRNAs were observed, although differences were noted for eIF-4A and eIF-4F. This finding suggests that eIF-4C is not involved in the binding of mRNA to 40 S ribosomal subunits. In heterologous assays, rabbit reticulocyte eIF-4C was as active as wheat germ eIF-4C in the wheat germ eIF-4C-dependent system. In addition, wheat germ eIF-4C substituted for rabbit reticulocyte eIF-4C in in vitro assay systems from rabbit reticulocytes. These results indicate that eIF-4C from wheat and rabbit contain conserved functional domains. PMID:8227048

Timmer, R T; Lax, S R; Hughes, D L; Merrick, W C; Ravel, J M; Browning, K S

1993-11-25

324

Loss of Sertoli-germ cell adhesion determines the rapid germ cell elimination during the seasonal regression of the seminiferous epithelium of the large hairy armadillo Chaetophractus villosus.  

PubMed

The armadillo Chaetophractus villosus is a seasonal breeder whose seminiferous epithelium undergoes rapid regression with massive germ cell loss, leaving the tubules with only Sertoli cells and spermatogonia. Here, we addressed the question of whether this regression entails 1) the disassembly of cell junctions (immunolocalization of nectin-3, Cadm1, N-cadherin, and beta-catenin, and transmission electron microscopy [TEM]); 2) apoptosis (immunolocalization of cytochrome c and caspase 3; TUNEL assay); and 3) the involvement of Sertoli cells in germ cell phagocytosis (TEM). We showed a dramatic reduction in the extension of vimentin filaments associated with desmosomelike junctions at the interface between Sertoli and germ cells, and an increased diffusion of the immunosignals of nectin-3, Cadm1, N-cadherin, and beta-catenin. Together, these results suggest loss of Sertoli-germ cell adhesion, which in turn might determine postmeiotic cell sloughing at the beginning of epithelium regression. Then, loss of Sertoli-germ cell adhesion triggers cell death. Cytochrome c is released from mitochondria, but although postmeiotic cells were negative for late apoptotic markers, at advanced regression spermatocytes were positive for all apoptotic markers. Transmission electron microscopy analysis showed cytoplasmic engulfment of cell debris and lipid droplets within Sertoli cells, a sign of their phagocytic activity, which contributes to the elimination of the residual meiocytes still present in the latest regression phases. These findings are novel and add new players to the mechanisms of seminiferous epithelium regression occurring in seasonal breeders, and they introduce the armadillo as an interesting model for studying seasonal spermatogenesis. PMID:24451984

Luaces, Juan Pablo; Rossi, Luis Francisco; Sciurano, Roberta Beatriz; Rebuzzini, Paola; Merico, Valeria; Zuccotti, Maurizio; Merani, Maria Susana; Garagna, Silvia

2014-03-01

325

Germ cell differentiation in the marmoset (Callithrix jacchus) during fetal and neonatal life closely parallels that in the human  

PubMed Central

BACKGROUND Testicular germ cell tumours (TGCT) are thought to originate from fetal germ cells that fail to differentiate normally, but no animal model for these events has been described. We evaluated the marmoset (Callithrix jacchus) as a model by comparing perinatal germ cell differentiation with that in humans. METHODS Immunohistochemical profiling was used to investigate germ cell differentiation (OCT4, NANOG, AP-2?, MAGE-A4, VASA, NANOS-1) and proliferation (Ki67) in fetal and neonatal marmoset testes in comparison with the human and, to a lesser extent, the rat. RESULTS In marmosets and humans, differentiation of gonocytes into spermatogonia is associated with the gradual loss of pluripotency markers such as OCT4 and NANOG, and the expression of germ cell-specific proteins such as VASA. This differentiation occurs asynchronously within individual cords during fetal and early postnatal life. This contrasts with rapid and synchronous germ cell differentiation within and between cords in the rat. Similarly, germ cell proliferation in the marmoset and human occurs throughout perinatal life, in contrast to rats in which proliferation ceases during this period. CONCLUSIONS The marmoset provides a good model for normal human germ cell differentiation and proliferation. The perinatal marmoset may be a useful model in which to establish factors that lead to failure of normal germ cell differentiation and the origins of TGCT. PMID:18694875

Mitchell, R.T.; Cowan, G.; Morris, K.D.; Anderson, R.A.; Fraser, H.M.; Mckenzie, K.J.; Wallace, W.H.B.; Kelnar, C.J.H.; Saunders, P.T.K.; Sharpe, R.M.

2008-01-01

326

Novel somatic and germline mutations in intracranial germ cell tumours.  

PubMed

Intracranial germ cell tumours (IGCTs) are a group of rare heterogeneous brain tumours that are clinically and histologically similar to the more common gonadal GCTs. IGCTs show great variation in their geographical and gender distribution, histological composition and treatment outcomes. The incidence of IGCTs is historically five- to eightfold greater in Japan and other East Asian countries than in Western countries, with peak incidence near the time of puberty. About half of the tumours are located in the pineal region. The male-to-female incidence ratio is approximately 3-4:1 overall, but is even higher for tumours located in the pineal region. Owing to the scarcity of tumour specimens available for research, little is currently known about this rare disease. Here we report the analysis of 62 cases by next-generation sequencing, single nucleotide polymorphism array and expression array. We find the KIT/RAS signalling pathway frequently mutated in more than 50% of IGCTs, including novel recurrent somatic mutations in KIT, its downstream mediators KRAS and NRAS, and its negative regulator CBL. Novel somatic alterations in the AKT/mTOR pathway included copy number gains of the AKT1 locus at 14q32.33 in 19% of patients, with corresponding upregulation of AKT1 expression. We identified loss-of-function mutations in BCORL1, a transcriptional co-repressor and tumour suppressor. We report significant enrichment of novel and rare germline variants in JMJD1C, which codes for a histone demethylase and is a coactivator of the androgen receptor, among Japanese IGCT patients. This study establishes a molecular foundation for understanding the biology of IGCTs and suggests potentially promising therapeutic strategies focusing on the inhibition of KIT/RAS activation and the AKT1/mTOR pathway. PMID:24896186

Wang, Linghua; Yamaguchi, Shigeru; Burstein, Matthew D; Terashima, Keita; Chang, Kyle; Ng, Ho-Keung; Nakamura, Hideo; He, Zongxiao; Doddapaneni, Harshavardhan; Lewis, Lora; Wang, Mark; Suzuki, Tomonari; Nishikawa, Ryo; Natsume, Atsushi; Terasaka, Shunsuke; Dauser, Robert; Whitehead, William; Adekunle, Adesina; Sun, Jiayi; Qiao, Yi; Marth, Gábor; Muzny, Donna M; Gibbs, Richard A; Leal, Suzanne M; Wheeler, David A; Lau, Ching C

2014-07-10

327

Endogenous DNA Damage and Risk of Testicular Germ Cell Tumors  

SciTech Connect

Testicular germ cell tumors (TGCT) are comprised of two histologic groups, seminomas and nonseminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable endogenous DNA damage. To assess our hypothesis, we conducted a case-case analysis of seminomas and nonseminomas using the alkaline comet assay to quantify single-strand DNA breaks and alkali-labile sites. The Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort provided 112 TGCT cases (51 seminomas & 61 nonseminomas). A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modeled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with nonseminoma compared to seminoma (OR{sub 50th percentile} = 3.31, 95%CI: 1.00, 10.98; OR{sub 75th percentile} = 3.71, 95%CI: 1.04, 13.20; p for trend=0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR{sub 50th percentile} = 2.27, 95%CI: 0.75, 6.87; OR{sub 75th percentile} = 2.40, 95%CI: 0.75, 7.71; p for trend=0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that endogenous DNA damage levels are higher in patients who develop nonseminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma.

Cook, M B; Sigurdson, A J; Jones, I M; Thomas, C B; Graubard, B I; Korde, L; Greene, M H; McGlynn, K A

2008-01-18

328

Sequential resection of residual abdominal and thoracic masses after chemotherapy for metastatic non-seminomatous germ cell tumours.  

PubMed Central

Thirty-eight patients with advanced non-seminomatous germ cell tumours (NSGCTs) underwent multiple surgical interventions (two in 33 patients, three in four patients, four in one patient) after cisplatin-based chemotherapy. All patients had normal serum tumour markers but persistent radiographic masses. The larger mass was routinely resected first. Fifteen patients (39%) had dissimilar histological findings at sequential surgical procedures, 12 of whom demonstrated less favourable pathological features during the first operation and three at the second. Patients who underwent both retroperitoneal lymph node dissection (RPLND) and lung resection showed less favourable histological features in the retroperitoneum in nine cases and in the lung in three cases. Eight of 16 patients (50%) without mature teratoma in their primary tumours showed complete necrosis/fibrosis at all surgical interventions, whereas all patients whose primary tumour was classified as malignant teratoma intermediate demonstrated mature teratoma at least at one anatomical site. As histology of post-chemotherapy residual masses cannot be extrapolated from one anatomical site to another, patients usually are properly managed by excision of all residual masses. In particular, in patients with necrosis/fibrosis at lung resection omission of RPLND is not advised. PMID:7524606

Gerl, A.; Clemm, C.; Schmeller, N.; Dienemann, H.; Weiss, M.; Kriegmair, M.; Löhrs, U.; Wilmanns, W.

1994-01-01

329

Gender differences in the induction of chromosomal aberrations and gene mutations in rodent germ cells  

SciTech Connect

Germ cell mutagenicity testing provides experimental data to quantify genetic risk for exposed human populations. The majority of tests are performed with exposure of males, and female data are relatively rare. The reason for this paucity lies in the differences between male and female germ cell biology. Male germ cells are produced throughout reproductive life and all developmental stages can be ascertained by appropriate breeding schemes. In contrast, the female germ cell pool is limited, meiosis begins during embryogenesis and oocytes are arrested over long periods of time until maturation processes start for small numbers of oocytes during the oestrus cycle in mature females. The literature data are reviewed to point out possible gender differences of germ cells to exogenous agents such as chemicals or ionizing radiation. From the limited information, it can be concluded that male germ cells are more sensitive than female germ cells to the induction of chromosomal aberrations and gene mutations. However, exceptions are described which shed doubt on the extrapolation of experimental data from male rodents to the genetic risk of the human population. Furthermore, the female genome may be more sensitive to mutation induction during peri-conceptional stages compared to the male genome of the zygote. With few exceptions, germ cell experiments have been carried out under high acute exposure to optimize the effects and to compensate for the limited sample size in animal experiments. Human exposure to environmental agents, on the other hand, is usually chronic and involves low doses. Under these conditions, gender differences may become apparent that have not been studied so far. Additionally, data are reviewed that suggest a false impression of safety when responses are negative under high acute exposure of male rodents while a mutational response is induced by low chronic exposure. The classical (morphological) germ cell mutation tests are not performed anymore because they are animal and time consuming. Nevertheless, information is needed to place genetic risk extrapolations on more solid grounds and thereby to prevent an increased genetic burden to future generations. It is pointed out that modern molecular methodologies are available now to experimentally address the open questions.

Adler, Ilse-Dore [GSF-Institute of Experimental Genetics, Neuherberg D-85758 (Germany); Carere, Angelo [Istituto Superiore di Sanita, Viale Regina Elena 299, Rome 00161 (Italy); Eichenlaub-Ritter, Ursula [Institute of Genetechnology/Microbiology, University of Bielefeld, Bielefeld D-33501 (Germany)]. E-mail: EiRi@uni-bielefeld.de; Pacchierotti, Francesca [Section of Toxicology and Biomedical Sciences, ENEA, CR Casaccia, Via Anguillarese 301, Rome 00060 (Italy)

2007-05-15

330

[Testicular cancer - a matter of geography? Epidemiology and etiopathogenesis of germ cell tumors].  

PubMed

More than 90?% of testicular tumors are germ cell tumors. There is no doubt that ethnicity is one of the single overriding etiological factors in the development of these tumors. White males living in western industrialized countries, particularly in northern Europe show the highest incidence rates, whereas black males in Africa show the lowest. These differences are the result of interaction of genetic factors and exogenous noxious agents. Some of these agents are chemical substances with an estrogen-like effect. Many exogenous substances have been blamed for causing testicular cancer, but clear epidemiological evidence is lacking for most cases. Some well-established risk factors prevail, such as cryptorchidism, familial association, gonadal dysgenesis (intersex) and germ cell tumor in the contralateral testis. In terms of importance, overalimentation appears to outweigh occupation. The development of germ cell tumors is assumed to have an intrauterine origin through defect gonocytes which evolve into atypical germ cells of unclassified intratubular germ cell neoplasms. The trigger event is, however, the appearance of isochromosome 12p, which makes these cells aggressive and results in overt invasive testicular cancer. PMID:24744184

Mikuz, G

2014-05-01

331

Vasa identifies germ cells and critical stages of oogenesis in the Asian seabass.  

PubMed

Germ cells produce sperm and eggs for reproduction and fertility. The Asian seabass (Lates calcarifer), a protandrous marine fish, undergoes male-female sex reversal and thus offers an excellent model to study the role of germ cells in sex differentiation and sex reversal. Here we report the cloning and expression of vasa as a first germ cell marker in this organism. A 2241-bp cDNA was cloned by PCR using degenerate primers of conserved sequences and gene-specific primers. This cDNA contains a polyadenylation signal and a full open reading frame for 645 amino acid residues, which was designated as Lcvasa for the seabass vasa, as its predicted protein is homologous to Vasa proteins. The Lcvasa RNA is maternally supplied and specific to gonads in adulthood. By chromogenic and fluorescent in situ hybridization we revealed germ cell-specific Lcvasa expression in both the testis and ovary. Importantly, Lcvasa shows dynamic patterns of temporospatial expression and subcellular distribution during gametogenesis. At different stages of oogenesis, for example, Lcvasa undergoes nuclear-cytoplasmic redistribution and becomes concentrated preferentially in the Balbiani body of stage-II~III oocytes. Thus, the vasa RNA identifies both female and male germ cells in the Asian seabass, and its expression and distribution delineate critical stages of gametogenesis. PMID:24550690

Xu, Hongyan; Lim, Menghuat; Dwarakanath, Manali; Hong, Yunhan

2014-01-01

332

Autonomy in specification of primordial germ cells and their passive translocation in the sea urchin  

PubMed Central

The process of germ line determination involves many conserved genes, yet is highly variable. Echinoderms are positioned at the base of Deuterostomia and are crucial to understanding these evolutionary transitions, yet the mechanism of germ line specification is not known in any member of the phyla. Here we demonstrate that small micromeres (SMics), which are formed at the fifth cell division of the sea urchin embryo, illustrate many typical features of primordial germ cell (PGC) specification. SMics autonomously express germ line genes in isolated culture, including selective Vasa protein accumulation and transcriptional activation of nanos; their descendants are passively displaced towards the animal pole by secondary mesenchyme cells and the elongating archenteron during gastrulation; Cadherin (G form) has an important role in their development and clustering phenotype; and a left/right integration into the future adult anlagen appears to be controlled by a late developmental mechanism. These results suggest that sea urchin SMics share many more characteristics typical of PGCs than previously thought, and imply a more widely conserved system of germ line development among metazoans. PMID:22991443

Yajima, Mamiko; Wessel, Gary M.

2012-01-01

333

Dodonaea viscosa var. angustifolia Inhibits Germ Tube and Biofilm Formation by C. albicans  

PubMed Central

The virulence factors of Candida albicans are germ tube and biofilm formation, adherence to host tissues, and production of hydrolytic enzymes. This study investigated the effect of Dodonaea viscosa var. angustifolia extract on the germ tube and biofilm formation of C. albicans. Serum containing the three subinhibitory concentrations of leaf extract was inoculated with C. albicans, incubated, and viewed under a light microscope. Number of cells with germ tube was recorded and the results were analysed using Scheffe test for pairwise comparison. Biofilms were grown on coverslips in the presence of plant extracts and processed for scanning electron microscopy (SEM). Planktonic cells were grown in the presence of plant extract for 6?h and processed for electron microscopy (TEM). The crude plant extract significantly (P < 0.01) reduced the germ tube formation of C. albicans at 3.125 (85.36%), 1.56 (61.91%), and 0.78?mg/mL (26.27%) showing a concentration dependent effect. SEM results showed concentration dependent reduction in biofilm and hyphae formation. TEM results showed that the plant extract caused damage to the cell wall and cell membrane. DVA extract has ability to reduce virulence of C. albicans by inhibiting germ tube and biofilm formation through damage to the cell wall. Therefore, it has therapeutic potential. PMID:24223612

Naicker, Serisha Devi

2013-01-01

334

Human germ cell formation in xenotransplants of induced pluripotent stem cells carrying X chromosome aneuploidies.  

PubMed

Turner syndrome is caused by complete or partial loss of the second sex chromosome and is characterized by spontaneous fetal loss in >90% of conceptions. Survivors possess an array of somatic and germline clinical characteristics. Induced pluripotent stem cells (iPSCs) offer an opportunity for insight into genetic requirements of the X chromosome linked to Turner syndrome. We derived iPSCs from Turner syndrome and control individuals and examined germ cell development as a function of X chromosome composition. We demonstrate that two X chromosomes are not necessary for reprogramming or maintenance of pluripotency and that there are minimal differences in gene expression, at the single cell level, linked to X chromosome aneuploidies. Formation of germ cells, as assessed in vivo through a murine xenotransplantation model, indicated that undifferentiated iPSCs, independent of X chromosome composition, are capable of forming germ-cell-like cells (GCLCs) in vivo. In combination with clinical data regarding infertility in women with X chromosome aneuploidies, results suggest that two intact X chromosomes are not required for human germ cell formation, qualitatively or quantitatively, but rather are likely to be required for maintenance of human germ cells to adulthood. PMID:25242416

Dominguez, Antonia A; Chiang, H Rosaria; Sukhwani, Meena; Orwig, Kyle E; Reijo Pera, Renee A

2014-01-01

335

Human germ cell formation in xenotransplants of induced pluripotent stem cells carrying X chromosome aneuploidies  

PubMed Central

Turner syndrome is caused by complete or partial loss of the second sex chromosome and is characterized by spontaneous fetal loss in >90% of conceptions. Survivors possess an array of somatic and germline clinical characteristics. Induced pluripotent stem cells (iPSCs) offer an opportunity for insight into genetic requirements of the X chromosome linked to Turner syndrome. We derived iPSCs from Turner syndrome and control individuals and examined germ cell development as a function of X chromosome composition. We demonstrate that two X chromosomes are not necessary for reprogramming or maintenance of pluripotency and that there are minimal differences in gene expression, at the single cell level, linked to X chromosome aneuploidies. Formation of germ cells, as assessed in vivo through a murine xenotransplantation model, indicated that undifferentiated iPSCs, independent of X chromosome composition, are capable of forming germ-cell-like cells (GCLCs) in vivo. In combination with clinical data regarding infertility in women with X chromosome aneuploidies, results suggest that two intact X chromosomes are not required for human germ cell formation, qualitatively or quantitatively, but rather are likely to be required for maintenance of human germ cells to adulthood. PMID:25242416

Dominguez, Antonia A.; Chiang, H. Rosaria; Sukhwani, Meena; Orwig, Kyle E.; Reijo Pera, Renee A.

2014-01-01

336

Vasa Identifies Germ Cells and Critical Stages of Oogenesis in the Asian Seabass  

PubMed Central

Germ cells produce sperm and eggs for reproduction and fertility. The Asian seabass (Lates calcarifer), a protandrous marine fish, undergoes male-female sex reversal and thus offers an excellent model to study the role of germ cells in sex differentiation and sex reversal. Here we report the cloning and expression of vasa as a first germ cell marker in this organism. A 2241-bp cDNA was cloned by PCR using degenerate primers of conserved sequences and gene-specific primers. This cDNA contains a polyadenylation signal and a full open reading frame for 645 amino acid residues, which was designated as Lcvasa for the seabass vasa, as its predicted protein is homologous to Vasa proteins. The Lcvasa RNA is maternally supplied and specific to gonads in adulthood. By chromogenic and fluorescent in situ hybridization we revealed germ cell-specific Lcvasa expression in both the testis and ovary. Importantly, Lcvasa shows dynamic patterns of temporospatial expression and subcellular distribution during gametogenesis. At different stages of oogenesis, for example, Lcvasa undergoes nuclear-cytoplasmic redistribution and becomes concentrated preferentially in the Balbiani body of stage-II~III oocytes. Thus, the vasa RNA identifies both female and male germ cells in the Asian seabass, and its expression and distribution delineate critical stages of gametogenesis. PMID:24550690

Xu, Hongyan; Lim, Menghuat; Dwarakanath, Manali; Hong, Yunhan

2014-01-01

337

Retinoic acid derived from the fetal ovary initiates meiosis in mouse germ cells.  

PubMed

Meiotic initiation of germ cells at 13.5 dpc (days post-coitus) indicates female sex determination in mice. Recent studies reveal that mesonephroi-derived retinoic acid (RA) is the key signal for induction of meiosis. However, whether the mesonephroi is dispensable for meiosis is unclear and the role of the ovary in this meiotic process remains to be clarified. This study provides data that RA derived from fetal ovaries is sufficient to induce germ cell meiosis in a fetal ovary culture system. When fetal ovaries were collected from 11.5 to 13.5 dpc fetuses, isolated and cultured in vitro, germ cells enter meiosis in the absence of mesonephroi. To exclude RA sourcing from mesonephroi, 11.5 dpc urogenital ridges (UGRs; mesonephroi and ovary complexes) were treated with diethylaminobenzaldehyde (DEAB) to block retinaldehyde dehydrogenase (RALDH) activity in the mesonephros and the ovary. Meiosis occurred when DEAB was withdrawn and the mesonephros was removed 2 days later. Furthermore, RALDH1, rather than RALDH2, serves as the major RA synthetase in UGRs from 12.5 to 15.5 dpc. DEAB treatment to the ovary alone was able to block germ cell meiotic entry. We also found that exogenously supplied RA dose-dependently reduced germ cell numbers in ovaries by accelerating the entry into meiosis. These results suggest that ovary-derived RA is responsible for meiosis initiation. PMID:22886539

Mu, Xinyi; Wen, Jing; Guo, Meng; Wang, Jianwei; Li, Ge; Wang, Zhengpin; Wang, Yijing; Teng, Zhen; Cui, Yan; Xia, Guoliang

2013-03-01

338

Expression pattern of clinically relevant markers in paediatric germ cell- and sex-cord stromal tumours is similar to adult testicular tumours.  

PubMed

Paediatric germ cell tumours (GCTs) are rare and account for less than 3 % of childhood cancers. Like adult GCTs, they probably originate from primordial germ cells, but the pattern of histopathological types is different, and they occur predominantly in extragonadal sites along the body midline. Because they are rare, histology of paediatric GCTs is poorly documented, and it remains unclear to what extent they differ from adult GCTs. We have analysed 35 paediatric germ cell tumours and 5 gonadal sex-cord stromal tumours from prepubertal patients aged 0-15 years, to gain further knowledge, elaborate on clinical-pathological associations and better understand their developmental divergence. The tumours were screened for expression of stemness-related factors (OCT4, AP-2?, SOX2), classical yolk sac tumours (YSTs; AFP, SALL4), GCTs (HCG, PLAP, PDPN/D2-40), as well as markers for sex-cord stromal tumour (PDPN, GATA4). All YSTs expressed AFP and SALL4, with GATA4 present in 13/14. The majority of teratomas expressed SOX2 and PDPN, whereas SALL4 was found in 8/13 immature teratomas. Adult seminoma markers AP-2?, OCT4, SALL4 and PDPN were all expressed in dysgerminoma. We further report a previously unrecognised pathogenetic relationship between AFP and SALL4 in YST in that different populations of YST cells express either SALL4 or AFP, which suggests variable differentiation status. We also show that AP-2? is expressed in the granulosa layer of ovarian follicles and weakly expressed in immature but not in mature granulosa cell tumours. Our findings indicate that the expression pattern of these antigens is similar between paediatric and adult GCTs, even though they develop along different developmental trajectories. PMID:25074678

Mosbech, Christiane Hammershaimb; Svingen, Terje; Nielsen, John Erik; Toft, Birgitte Groenkaer; Rechnitzer, Catherine; Petersen, Bodil Laub; Rajpert-De Meyts, Ewa; Hoei-Hansen, Christina Engel

2014-11-01

339

Aggregation at the physical layer  

Microsoft Academic Search

Aggregation at the physical layer (APL) allows a single IEEE 802.3 media access control (MAC) sublayer to treat a collection of underlying physical layer (PHY) devices as a single logical link. APL creates Ethernet links with bandwidths greater than can be achieved with a single physical link. The primary purpose of APL is to support the next generation Ethernet link

Howard Frazier

2008-01-01

340

Primary aldosteronism.  

PubMed

Approaching the fiftieth year since its original description, primary aldosteronism is now thought to be the commonest potentially curable and specifically treatable form of hypertension. Correct identification of patients with primary aldosteronism requires that the effects of time of day, posture, dietary sodium intake, potassium levels and medications on levels of aldosterone and renin be carefully considered. Accurate elucidation of the subtype is essential for optimal treatment, and adrenal venous sampling is the only reliable means of differentiating aldosterone-producing adenoma from bilateral adrenal hyperplasia. With genetic testing already available for one inherited form, making more cumbersome biochemical testing for that subtype virtually obsolete and bringing about improvements in treatment approach, an intense search is underway for genetic mutations causing other, more common familial varieties of primary aldosteronism. PMID:14687591

Stowasser, Michael; Gordon, Richard D

2003-12-01

341

Layer 6 corticothalamic neurons activate a cortical output layer, layer 5a.  

PubMed

Layer 6 corticothalamic neurons are thought to modulate incoming sensory information via their intracortical axons targeting the major thalamorecipient layer of the neocortex, layer 4, and via their long-range feedback projections to primary sensory thalamic nuclei. However, anatomical reconstructions of individual layer 6 corticothalamic (L6 CT) neurons include examples with axonal processes ramifying within layer 5, and the relative input of the overall population of L6 CT neurons to layers 4 and 5 is not well understood. We compared the synaptic impact of L6 CT cells on neurons in layers 4 and 5. We found that the axons of L6 CT neurons densely ramified within layer 5a in both visual and somatosensory cortices of the mouse. Optogenetic activation of corticothalamic neurons generated large EPSPs in pyramidal neurons in layer 5a. In contrast, excitatory neurons in layer 4 exhibited weak excitation or disynaptic inhibition. Fast-spiking parvalbumin-positive cells in both layer 5a and layer 4 were also strongly activated by L6 CT neurons. The overall effect of L6 CT activation was to suppress layer 4 while eliciting action potentials in layer 5a pyramidal neurons. Together, our data indicate that L6 CT neurons strongly activate an output layer of the cortex. PMID:25031405

Kim, Juhyun; Matney, Chanel J; Blankenship, Aaron; Hestrin, Shaul; Brown, Solange P

2014-07-16

342

Metastable primordial germ cell-like state induced from mouse embryonic stem cells by Akt activation  

SciTech Connect

Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, indicating that the sphere cells had commenced differentiation to the germ lineage. However, the spheres did not proceed to spermatogenesis after transplantation into testes. Sphere cell transfer to the original feeder-free ESC cultures resulted in chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, reversion to the ESC-like state was observed. These results indicate that Akt signaling promotes a novel metastable and pluripotent state that is intermediate to those of ESCs and PGCs.

Yamano, Noriko [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Kimura, Tohru, E-mail: tkimura@patho.med.osaka-u.ac.jp [Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Watanabe-Kushima, Shoko [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Shinohara, Takashi [Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501 (Japan)] [Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501 (Japan); Nakano, Toru, E-mail: tnakano@patho.med.osaka-u.ac.jp [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan) [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2010-02-12

343

Functional lacrimal gland regeneration by transplantation of a bioengineered organ germ  

PubMed Central

The lacrimal gland has a multifaceted role in maintaining a homeostatic microenvironment for a healthy ocular surface via tear secretion. Dry-eye disease, which is caused by lacrimal gland dysfunction, is one of the most prevalent eye diseases that cause corneal epithelial damage and results in significant loss of vision and a reduction in the quality of life. Here we demonstrate orthotopic transplantation of bioengineered lacrimal gland germs into adult mice with an extra-orbital lacrimal gland defect, a mouse model that mimics the corneal epithelial damage caused by lacrimal gland dysfunction. The bioengineered lacrimal gland germs and harderian gland germs both develop in vivo and achieve sufficient physiological functionality, including tear production in response to nervous stimulation and ocular surface protection. This study demonstrates the potential for bioengineered organ replacement to functionally restore the lacrimal gland. PMID:24084941

Hirayama, Masatoshi; Ogawa, Miho; Oshima, Masamitsu; Sekine, Yurie; Ishida, Kentaro; Yamashita, Kentaro; Ikeda, Kazutaka; Shimmura, Shigeto; Kawakita, Tetsuya; Tsubota, Kazuo; Tsuji, Takashi

2013-01-01

344

Metastable primordial germ cell-like state induced from mouse embryonic stem cells by Akt activation.  

PubMed

Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, indicating that the sphere cells had commenced differentiation to the germ lineage. However, the spheres did not proceed to spermatogenesis after transplantation into testes. Sphere cell transfer to the original feeder-free ESC cultures resulted in chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, reversion to the ESC-like state was observed. These results indicate that Akt signaling promotes a novel metastable and pluripotent state that is intermediate to those of ESCs and PGCs. PMID:20059970

Yamano, Noriko; Kimura, Tohru; Watanabe-Kushima, Shoko; Shinohara, Takashi; Nakano, Toru

2010-02-12

345

Advances in the management of central nervous system germ cell tumors.  

PubMed

Intracranial germ cell tumors represent a relatively small portion of pediatric central nervous system tumors, with a reported incidence ranging from 3.6% in North America to 15.3% in parts of Asia. They are known to arise in midline locations, most frequently the pineal gland and suprasellar regions, and affect males twice to three times more frequently than females, especially in the case of pineal-region tumors. The median age of diagnosis is 10-12 years. The treatment of intracranial germ cells tumors is complicated by their relative rarity, histologic heterogeneity, and a lack of widespread consensus on their optimal management. Despite these challenges, important progress continues to be made, with a move toward multicenter and international collaborative efforts that offer potential for clinical advancements. This review focuses on recent developments in the management of intracranial germ cell tumors, including updates in diagnosis, surveillance, biology, treatment, and outcomes. PMID:24838613

Millard, Nathan E; Dunkel, Ira J

2014-07-01

346

Behaviour of the germ cell specific lamin through mammalian spermatogenesis as probed with monoclonal antibodies.  

PubMed

We had earlier identified a 60 kDa nuclear lamin protein (lamin(g)) unique to the germ cells of rat testis which was subsequently shown to be antigenically conserved in germ cells of grasshopper, rooster, frog and plants. We have now obtained eight monoclonal antibodies in mouse against this lamin(g) antigen. While all the eight Mabs reacted with lamin(g) antigen in an immunoblot analysis, only three Mabs (A11C7, A11D4, C1F7) showed strong reactivity in the immunofluorescence analysis of the germ cells. The Mabs A11C7 and A11D4 showed a slight cross-reactivity with rat liver lamin B. Indirect immunofluorescence analysis of pre-meiotic, meiotic and post-meiotic germ cells with Mabs have shown that while the lamin(g) is localized in the lamina structures of spermatogonia and round spermatids, it is localized to the phase dense regions of pachytene spermatocytes which is in conformity with our previous observations using rabbit polyclonal antibodies. The localization of the antigen in the germ cells was also confirmed by immunohistochemical staining of the thin sections of seminiferous tubules. By immunostaining the surface spread pachytene spermatocytes, the antigen was further localized to the telomeric ends of the paired homologous chromosomes. Using anti-somatic lamin B antibodies, we have also demonstrated the absence of somatic lamins in meiotic and post-meiotic germ cells. The lamina structure of pre-meiotic spermatogonial nucleus contains both somatic lamin B and lamin(g) as evidenced by immunofluorescence studies with two differently fluorochrome labelled anti-lamin B and anti-lamin(g) antibodies. The selective retention of lamin(g) in the pachytene spermatocytes is probably essential for anchoring the telomeric ends of the paired chromosomes to the inner nuclear membrane. PMID:7820872

Manjula, K; Karande, A; Rao, M R

1994-08-01

347

RA induces differentiation of multipotent P19 cells towards male germ cell.  

PubMed

Generating male germ cells in vitro from multipotent stem cells is still a challenge for stem cell biologists. The difficulty is caused by the lack of knowledge about spermatogenesis molecular-controlling mechanisms. In vivo, PGCs differentiate into male germ cells in a very complicated environment through many middle steps. In this study, we use the pluripotent p19 cells to test their responses to different retinoic acid (RA) concentrations by evaluating markers for stem cells (bmp4, egr3), primordial germ cells (ddx4), spermatogonia (c-kit), premeiotic cells (stra8), and male germ cells (dazl and plzf). We have found that cyp26b1, which will catalyze RA, increases dramatically in p19 cells 1 d after RA treatment. Bmp3, egr3, and stra8 are stimulated after 1 d of RA treatment and then recover to normal after 3 d of RA treatment. C-kit keeps being expressed when treated with 10 nM-4 ?M RA. Dazl and plzf are gained after 3 d of stimulation. The morphology of RA (100 nM-4 ?M)-treated cells changes distinctively, and cell colonies are formed. Typical neural cell-like and germ cell-like morphologies appear in the 100 nM and 4 ?M RA groups, respectively. We conclude that 100-500 nM RA can cause responses in p19 cells, but a high concentration of RA (1-4 ?M) can drive these pluripotent cells' differentiation towards male germ cells. However, high concentrations of RA are also toxic. Some colonies that survived from 4 ?M RA begin to express ddx4 and c-kit. Selection of the c-kit (+) , dazl (+) , and ddx4 (+) cells after RA stimulation and creating a special culture medium for their propagation might benefit successful spermatogenesis induction in vitro. PMID:25537091

Zhang, Lei; Tang, Jiangjing; Haines, Christopher J; Feng, Huai; Teng, Xiaoming; Han, Yibing

2015-01-01

348

Characterization and in vitro culture of male germ cells from developing bovine testis.  

PubMed

The transition from male primitive germ cells (gonocytes) to type A spermatogonia in the neonatal testis is the initial process and a crucial process in spermatogenesis. However, in large domestic animals, the physiological and biochemical characteristics of germ cells during the developmental processes remain largely unknown. In this study, we characterized bovine germ cells in the developing testis from the neonatal stage to the adult stage. The binding of the lectin Dolichos biflorus agglutinin (DBA) and the expression of ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) were restricted to gonocytes in the neonatal testis and spermatogonia in the adult testis. Gonocytes also expressed a germ cell marker (VASA) and stem cell markers (NANOG and OCT3/4), while the expressions of these markers in the adult testis were restricted to differentiated spermatic cells and were rarely expressed in spermatogonia. We subsequently utilized these markers to characterize gonocytes and spermatogonia after culture in vitro. Spermatogonia that were collected from the adult testis formed colonies in vitro only for one week. On the other hand, gonocytes from the neonatal testis could proliferate and form colonies after every passage for 1.5 months in culture. These colonies retained undifferentiated states of gonocytes as confirmed by the expression of both germ cell and stem cell markers. Moreover, a transplantation assay using immunodeficient mice testes showed that long-term cultured cells derived from gonocytes were able to colonize in the recipient testis. These results indicated that bovine gonocytes could maintain germ cell and stem cell potential in vitro. PMID:21289464

Fujihara, Mayako; Kim, Sung-Min; Minami, Naojiro; Yamada, Masayasu; Imai, Hiroshi

2011-06-01

349

Doubly Uniparental Inheritance of Mitochondria As a Model System for Studying Germ Line Formation  

PubMed Central

Background Doubly Uniparental Inheritance (DUI) of mitochondria occurs when both mothers and fathers are capable of transmitting mitochondria to their offspring, in contrast to the typical Strictly Maternal Inheritance (SMI). DUI was found in some bivalve molluscs, in which two mitochondrial genomes are inherited, one through eggs, the other through sperm. During male embryo development, spermatozoon mitochondria aggregate in proximity of the first cleavage furrow and end up in the primordial germ cells, while they are dispersed in female embryos. Methodology/Principal Findings We used MitoTracker, microtubule staining and transmission electron microscopy to examine the mechanisms of this unusual distribution of sperm mitochondria in the DUI species Ruditapes philippinarum. Our results suggest that in male embryos the midbody deriving from the mitotic spindle of the first division concurs in positioning the aggregate of sperm mitochondria. Furthermore, an immunocytochemical analysis showed that the germ line determinant Vasa segregates close to the first cleavage furrow. Conclusions/Significance In DUI male embryos, spermatozoon mitochondria aggregate in a stable area on the animal-vegetal axis: in organisms with spiral segmentation this zone is not involved in cleavage, so the aggregation is maintained. Moreover, sperm mitochondria reach the same embryonic area in which also germ plasm is transferred. In 2-blastomere embryos, the segregation of sperm mitochondria in the same region with Vasa suggests their contribution in male germ line formation. In DUI male embryos, M-type mitochondria must be recognized by egg factors to be actively transferred in the germ line, where they become dominant replacing the Balbiani body mitochondria. The typical features of germ line assembly point to a common biological mechanism shared by DUI and SMI organisms. Although the molecular dynamics of the segregation of sperm mitochondria in DUI species are unknown, they could be a variation of the mechanism regulating the mitochondrial bottleneck in all metazoans. PMID:22140544

Milani, Liliana; Ghiselli, Fabrizio; Maurizii, Maria Gabriella; Passamonti, Marco

2011-01-01

350

Congenital Cerebellar Mixed Germ Cell Tumor Presenting with Hemorrhage in a Newborn  

PubMed Central

We report here on a neonate with congenital cerebellar mixed germ cell tumor, and this initially presented as cerebellar hemorrhage. Postnatal cranial ultrasonography revealed an echogenic cerebellar mass that exhibited the signal characteristics of hemorrhage rather than tumor on MR images. The short-term follow-up images also suggested a resolving cerebellar hemorrhage. One month later, the neonate developed vomiting. A second set of MR images demonstrated an enlarged mass that exhibited changed signal intensity at the same site, which suggested a neoplasm. Histological examination after the surgical resection revealed a mixed germ cell tumor. PMID:18607121

Kim, Sung Mok; Yoo, So-Young; Park, Won Soon; Jang, Yun-Sil; Shin, Hyung-Jin; Suh, Yeon-Lim

2008-01-01

351

Ghrelin modulates testicular germ cells apoptosis and proliferation in adult normal rats  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. Black-Right-Pointing-Pointer Numerous studies have documented the direct action of ghrelin in the modulation of apoptosis in different cell types. Black-Right-Pointing-Pointer Ghrelin may be considered as a modulator of spermatogenesis in normal adult rats. Black-Right-Pointing-Pointer Ghrelin may be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors. -- Abstract: Under normal condition in the most mammals, spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. The present study was designed to determine the effects of ghrelin treatment on in vivo quality and quantity expression of apoptosis and proliferation specific indices in rat testicular germ cells. Twenty eight adult normal rats were subdivided into equal control and treatment groups. Treatment group received 3 nmol of ghrelin as subcutaneous injection for 30 consecutive days or vehicle to the control animals. The rats from each group (n = 7) were killed on days 10 and 30 and their testes were taken for immunocytochemical evaluation and caspase-3 assay. Immunohistochemical analysis indicated that the accumulations of Bax and PCNA peptides are generally more prominent in spermatocytes and spermatogonia of both groups. Likewise, the mean percentage of immunoreactive spermatocytes against Bax increased (P < 0.01) in the ghrelin-treated group on day 10, while despite of 30% increment in the Bax level of spermatocytes in the treated rats on day 30, however, it was not statistically significant. During the experimental period, only a few spermatogonia represented Bax expression and the changes of Bax immunolabling cells were negligible upon ghrelin treatment. Likewise, there were immunostaining cells against Bcl-2 in each germ cell neither in the control nor in the treated animals. In fact, ghrelin balanced Bax/Bcl-2 ratio toward at increase of Bax level in the spermatocytes and therefore may stimulate apoptosis in these germ cells. In contrast, ghrelin administration significantly suppressed proliferation-associated peptide PCNA in the spermatocytes as well as spermatogonia (P < 0.05). Whereas, caspase-3 activity did not show any marked alteration during the experiment in both groups (P > 0.05). Upstream of Bax substance parallel to down-regulation of PCNA demonstrate that ghrelin may prevent massive accumulation of germ cells during normal spermatogenesis. These observations also indicate that ghrelin may be considered as a modulator of spermatogenesis in normal adult rats and could be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors.

Kheradmand, Arash, E-mail: arashkheradmand@yahoo.com [Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of)] [Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Dezfoulian, Omid [Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorram Abad (Iran, Islamic Republic of)] [Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorram Abad (Iran, Islamic Republic of); Alirezaei, Masoud [Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of)] [Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Rasoulian, Bahram [Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorram Abad (Iran, Islamic Republic of)] [Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorram Abad (Iran, Islamic Republic of)

2012-03-09

352

Two waves of de novo methylation during mouse germ cell development  

PubMed Central

During development, mammalian germ cells reprogram their epigenomes via a genome-wide erasure and de novo rewriting of DNA methylation marks. We know little of how methylation patterns are specifically determined. The piRNA pathway is thought to target the bulk of retrotransposon methylation. Here we show that most retrotransposon sequences are modified by default de novo methylation. However, potentially active retrotransposon copies evade this initial wave, likely mimicking features of protein-coding genes. These elements remain transcriptionally active and become targets of piRNA-mediated methylation. Thus, we posit that these two waves play essential roles in resetting germ cell epigenomes at each generation. PMID:25030694

Molaro, Antoine; Falciatori, Ilaria; Hodges, Emily; Aravin, Alexei A.; Marran, Krista; Rafii, Shahin; McCombie, W. Richard; Smith, Andrew D.; Hannon, Gregory J.

2014-01-01

353

Malignant pineal germ-cell tumors: An analysis of cases from three tumor registries  

PubMed Central

The exact incidence of pineal germ-cell tumors is largely unknown. The tumors are rare, and the number of patients with these tumors, as reported in clinical series, has been limited. The goal of this study was to describe pineal germ-cell tumors in a large number of patients, using data from available brain tumor databases. Three different databases were used: Surveillance, Epidemiology, and End Results (SEER) database (1973–2001); Central Brain Tumor Registry of the United States (CBTRUS; 1997–2001); and National Cancer Data Base (NCDB; 1985–2003). Tumors were identified using the International Classification of Diseases for Oncology, third edition (ICD-O-3), site code C75.3, and categorized according to histology codes 9060–9085. Data were analyzed using SAS/STAT release 8.2, SEER*Stat version 5.2, and SPSS version 13.0 software. A total of 1,467 cases of malignant pineal germ-cell tumors were identified: 1,159 from NCDB, 196 from SEER, and 112 from CBTRUS. All three databases showed a male predominance for pineal germ-cell tumors (>90%), and >72% of patients were Caucasian. The peak number of cases occurred in the 10- to 14-year age group in the CBTRUS data and in the 15- to 19-year age group in the SEER and NCDB data, and declined significantly thereafter. The majority of tumors (73%–86%) were germinomas, and patients with germinomas had the highest survival rate (>79% at 5 years). Most patients were treated with surgical resection and radiation therapy or with radiation therapy alone. The number of patients included in this study exceeds that of any study published to date. The proportions of malignant pineal germ-cell tumors and intracranial germ-cell tumors are in range with previous studies. Survival rates for malignant pineal germ-cell tumors are lower than results from recent treatment trials for intracranial germ-cell tumors, and patients that received radiation therapy in the treatment plan either with surgery or alone survived the longest. PMID:18287340

Villano, J. Lee; Propp, Jennifer M.; Porter, Kimberly R.; Stewart, Andrew K.; Valyi-Nagy, Tibor; Li, Xinyu; Engelhard, Herbert H.; McCarthy, Bridget J.

2008-01-01

354

Radical Resection of a Late-Relapsed Testicular Germ Cell Tumour: Hepatectomy, Cavotomy, and Thrombectomy  

PubMed Central

Up to 3.2% of patients with testicular germ cell tumours represent with late-relapsing disease. Aggressive surgical resection confers the greatest chance of cure in this patient group. We present the case of a late and extensively relapsed nonseminomatous germ cell tumour with thrombus present along the entire length of the inferior vena cava, as well as in the right hepatic vein. Techniques practised in liver transplantation were used to achieve complete resection of the tumour thrombus. This case illustrates the enhanced potential for tumour resection through a fusion of principles derived from surgical oncology and liver transplantation. PMID:25587480

Ní Leidhin, C.; Redmond, C. E.; Cahalane, A. M.; Heneghan, H. M.; Motyer, R.; Ryan, E. R.; Hoti, E.

2014-01-01

355

A role for Dazl in commitment to gametogenic fate in embryonic germ cells of C57BL/6 mice  

E-print Network

Germ cells can be defined as the cells that undergo the terminal differentiating process of meiosis. In mice, as XX germ cells enter meiosis around Embryonic days 13.5-14.5 (E13.5-E14.5), they form meiotic figures and ...

Lin, Yanfeng, Ph. D. Massachusetts Institute of Technology

2005-01-01

356

Analysis of a novel gene, Sdgc, reveals sex chromosome-dependent differences of medaka germ cells prior to gonad formation.  

PubMed

In vertebrates that have been examined to date, the sexual identity of germ cells is determined by the sex of gonadal somatic cells. In the teleost fish medaka, a sex-determination gene on the Y chromosome, DMY/dmrt1bY, is expressed in gonadal somatic cells and regulates the sexual identity of germ cells. Here, we report a novel mechanism by which sex chromosomes cell-autonomously confer sexually different characters upon germ cells prior to gonad formation in a genetically sex-determined species. We have identified a novel gene, Sdgc (sex chromosome-dependent differential expression in germ cells), whose transcripts are highly enriched in early XY germ cells. Chimeric analysis revealed that sexually different expression of Sdgc is controlled in a germ cell-autonomous manner by the number of Y chromosomes. Unexpectedly, DMY/dmrt1bY was expressed in germ cells prior to gonad formation, but knockdown and overexpression of DMY/dmrt1bY did not affect Sdgc expression. We also found that XX and XY germ cells isolated before the onset of DMY/dmrt1bY expression in gonadal somatic cells behaved differently in vitro and were affected by Sdgc. Sdgc maps close to the sex-determination locus, and recombination around the two loci appears to be repressed. Our results provide important insights into the acquisition and plasticity of sexual differences at the cellular level even prior to the developmental stage of sex determination. PMID:25078651

Nishimura, Toshiya; Herpin, Amaury; Kimura, Tetsuaki; Hara, Ikuyo; Kawasaki, Toshihiro; Nakamura, Shuhei; Yamamoto, Yasuhiro; Saito, Taro L; Yoshimura, Jun; Morishita, Shinichi; Tsukahara, Tatsuya; Kobayashi, Satoru; Naruse, Kiyoshi; Shigenobu, Shuji; Sakai, Noriyoshi; Schartl, Manfred; Tanaka, Minoru

2014-09-01

357

Modification of aqueous enzymatic oil extraction to increase the yield of corn oil from dry fractionated corn germ  

Technology Transfer Automated Retrieval System (TEKTRAN)

In previous aqueous enzymatic extraction experiments we reported an oil yield of 67 grams from 800 grams of dry fractionated corn germ. In the current experiments, a dispersion of 10% cooked, dry-fractionated germ in water and was treated with amylases and a cellulase complex. A foam fraction was s...

358

vasa and nanos expression patterns in a sea anemone and the evolution of bilaterian germ cell specification mechanisms  

E-print Network

, but also in multiple somatic cell types during early embryogenesis. These results suggest one way in which Most bilaterians specify primordial germ cells (PGCs) during early embryogenesis using either inherited specified during embryogenesis (primordial germ cells or PGCs) is not significantly amplified, renewed

Extavour, Cassandra

359

Genome-Wide Profiling of Pluripotent Cells Reveals a Unique Molecular Signature of Human Embryonic Germ Cells  

Microsoft Academic Search

Human embryonic germ cells (EGCs) provide a powerful model for identifying molecules involved in the pluripotent state when compared to their progenitors, primordial germ cells (PGCs), and other pluripotent stem cells. Microarray and Principal Component Analysis (PCA) reveals for the first time that human EGCs possess a transcription profile distinct from PGCs and other pluripotent stem cells. Validation with qRT-PCR

Nikta Pashai; Haiping Hao; Angelo All; Siddharth Gupta; Raghothama Chaerkady; John D. Gearhart; Candace L. Kerr

2012-01-01

360

Isolipidic additions of fat from corn germ, corn distillers grains, or corn oil in dairy cow diets1  

Microsoft Academic Search

Eight multiparous and 8 primiparous Holstein cows were used in a replicated 4 × 4 Latin square design with 4-wk periods to determine the effects on dairy cow performance of feeding corn germ (CG) compared with dried distillers grains with solubles (DDGS) or corn oil (CO). Four isolipidic dietary treatments were formu- lated: a control diet, a 14% corn germ

M. M. Abdelqader; A. R. Hippen; K. F. Kalscheur; D. J. Schingoethe; A. D. Garcia

2009-01-01

361

Retroperitoneal dedifferentiated liposarcoma lacking MDM2 amplification in a patient with a germ line CHEK2 mutation.  

PubMed

Germ line mutations in genes that encode proteins involved in the DNA damage response predispose patients to a variety of tumors. Checkpoint kinase 2, encoded by the CHEK2 gene, is important in transducing the DNA damage response. Germ line CHEK2 mutations are seen in a subset of patients with a familial breast cancer and sarcoma phenotype. We report a case of retroperitoneal dedifferentiated liposarcoma in a 61-year-old female with germ line CHEK2 mutation. MDM2 gene amplification normally present and used to aid in the diagnosis of retroperitoneal dedifferentiated liposarcoma was absent in this case. Lack of MDM2 overexpression has similarly been reported in liposarcomas arising in patients with germ line TP53 mutations. We propose this case may highlight a nonamplified MDM2 phenotype in well- and dedifferentiated liposarcomas arising in patients with germ line mutations of genes involved in p53-associated DNA damage response pathways. PMID:24595525

Sadri, Navid; Surrey, Lea F; Fraker, Douglas L; Zhang, Paul J

2014-04-01

362

Simultaneous gene deletion of gata4 and gata6 leads to early disruption of follicular development and germ cell loss in the murine ovary.  

PubMed

Granulosa cell formation and subsequent follicular assembly are important for ovarian development and function. Two members of the GATA family of transcription factors, GATA4 and GATA6, are expressed in ovarian somatic cells early in development, and their importance in adult ovarian function has been recently highlighted. In this study, we demonstrated that the embryonic loss of Gata4 and Gata6 expression within the ovary results in a strong down-regulation of genes involved in the ovarian developmental pathway (Fst and Irx3) as well as diminished expression of the pregranulosa and granulosa cell markers SPRR2 and FOXL2, respectively. Postnatal ovaries deficient in both Gata genes show impaired somatic cell proliferation and arrested follicular development at the primordial stage, where oocytes are either enclosed by one layer of squamous granulosa cells or remain in germ cell nests/clusters. Furthermore, germ cell nests and primordial follicles are predominantly localized to the central region of the Sf1Cre; Gata4(flox/flox) Gata6(flox/flox) ovaries, where the boundary between the medulla and cortex is almost nonexistent. Lastly, most of the oocytes are lost early in development in conditional double mutant ovaries, which confirms the importance of normally differentiated granulosa cells as supporting cells for oocyte survival. Thus, both GATA4 and GATA6 proteins are fundamental regulators of granulosa cell differentiation and proliferation, and consequently of proper follicular assembly during normal ovarian development and function. PMID:24899573

Padua, Maria B; Fox, Shawna C; Jiang, Tianyu; Morse, Deborah A; Tevosian, Sergei G

2014-07-01

363

Primary neuroleptospirosis  

PubMed Central

Leptospirosis is an important zoonosis of worldwide distribution. It is uncommon for leptospirosis to present as a primary neurological disease. In this study of patients who presented with an acute neurological disease, and who were subsequently found to have leptospirosis, aseptic meningitis was the commonest manifestation. The other presentations were myeloradiculopathy, myelopathy, Guillain-Barré syndrome-like presentation, meningoencephalitis, intracerebral bleed, cerebellar dysfunction, iridocyclitis, and tremor/rigidity. Treatment consists of antibiotics, crystalline penicillin being the drug of choice, which reduces the course of illness if given early. The role of steroids is controversial. The prognosis after primary neuroleptospirosis is generally good but altered sensorium and seizures herald a worse prognosis.???Keywords: neuroleptospirosis; aseptic meningitis; Weil's disease PMID:11524519

Panicker, J; Mammachan, R; Jayakumar, R

2001-01-01

364

MEETING REPORT ASSESSING HUMAN GERM-CELL MUTAGENESIS IN THE POST-GENOME ERA: A CELEBRATION OF THE LEGACY OF WILLIAM LAWSON (BILL) RUSSELL  

EPA Science Inventory

Although numerous germ-cell mutagens have been identified in animal model systems, to date, no human germ-cell mutagens have been confirmed. Because the genomic integrity of our germ cells is essential for the continuation of the human species, a resolution of this enduring conu...

365

Dazl Functions in Maintenance of Pluripotency and Genetic and Epigenetic Programs of Differentiation in Mouse Primordial Germ Cells In Vivo and In Vitro  

Microsoft Academic Search

BackgroundMammalian 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 mammalian germ cell development both in vivo, and during differentiation

Kelly M. Haston; Joyce Y. Tung; Renee A. Reijo Pera; Chad Creighton

2009-01-01

366

Maintaining a Sanitary Child Care Environment -- Six Tips for Germ Control.  

ERIC Educational Resources Information Center

Recommends keeping body defenses strong, and keeping all surfaces clean and some surfaces sanitary. Urges using federally mandated precautions for blood spills, avoiding germ-trapping artificial or long fingernails and jewelry, practicing good hand washing, and organizing the environment to avoid contamination. Includes table relating child care…

Aronson, Susan S.

2001-01-01

367

USE OF MUELLER-HINTON BROTH AND AGAR IN THE GERM TUBE TEST  

PubMed Central

Candida albicans is often isolated from clinical samples, thus its presumptive differentiation from other species of the same genus can be based on its ability to form the germ tube in human serum. Nevertheless, there are two other species that share this characteristic: C. dubliniensis and C. africana. The aim of this study was to compare four different substrates to perform the germ tube (GT) test. The Candida spp. isolates were identified using a manual system (135 C. albicans, 24 C. tropicalis and one C. dubliniensis). The germ tube test was performed with fresh, previously frozen serum and Mueller-Hinton (MH) broth and agar. GT was observed in 96% (130/136) of the isolates through the fresh serum technique, 94% (128/136) through previously frozen serum, 92% (125/136) in MH agar, and 90% (122/136) in MH broth. The sensitivity of each test was higher than 90%, with 100% specificity. Both the MH agar and broth were able to identify the true positives, and false positives were not found. However, some C. albicans isolates were not identified. MH agar and broth may be used in laboratory for the rapid presumptive identification of C. albicans, as an alternative method for germ tube test. PMID:25351541

Mattei, Antonella Souza; Alves, Sydney Hartz; Severo, Cecília Bittencourt; Guazzelli, Luciana da Silva; Oliveira, Flávio de Mattos; Severo, Luiz Carlos

2014-01-01

368

TERATOMA WITH MALIGNANT TRANSFORMATION: DIVERSE MALIGNANT HISTOLOGIES ARISING IN MEN WITH GERM CELL TUMORS  

Microsoft Academic Search

PurposeTeratoma with malignant transformation refers to a form of germ cell tumor in which a somatic teratomatous component becomes morphologically malignant and develops aggressive growth. We evaluated the spectrum of histologies, chromosomal abnormalities and clinical outcome in patients with teratoma with malignant transformation.

Robert J. Motzer; Alison Amsterdam; Victor Prieto; Joel Sheinfeld; V. V. V. S. Murty; Madhu Mazumdar; George J. Bosl; R. S. K. Chaganti; Victor E. Reuter

1998-01-01

369

The current algebra on the circle as a germ of local field theories  

Microsoft Academic Search

Methods of algebraic quantum field theory are used to classify all field- and observable algebras, whose common germ is the U(1)-current algebra. An elementary way is described to compute characters of such algebras. It exploits the Kubo-Martin-Schwinger condition for Gibbs states..

Detlev Buchholz; Gerhard Mack; Ivan Todorov

1988-01-01

370

Characterization of a highly efficient protein synthesizing system derived from commercial wheat germ*  

PubMed Central

A crude extract of commercial wheat germ is capable of translating mRNAs from widely different sources with high efficiencies. Of six wheat germs analyzed only one was found capable of a high level or incorporation with natural mRNAs. Under optimum conditions at a saturating level of Tobacco Mosaic Virus (TMV) RNA (4.5 ?g) and labeled amino acid, 68% of all the available 14C leucine is incorporated in 70 min. at 30°C with a stimulation of 425 fold above background (with an efficiency of 252 moles leucine/mole TMV RNA). Thus this system which is 30 fold more efficient for TMV translation than previous reported wheat germ cell free systems is capable of yielding 568 pmoles of 14C leucine incorporated into protein in a 50 ?l assay. 80% of the proteins produced have a molecular weight greater than TMV coat protein (17,400). This level of incorporation requires optimization of extract concentration, pH, Mg+2, K+ and spermine concentration as well as the method of extract preparation. Samples of crude polysomal RNA from hen oviducts (3% mRNA) and chorionating moth follicular cells (1% mRNA) are also translated in the wheat germ cell free system with high efficiency. PMID:10793698

Marcu, K.; Dudock, B.

1974-01-01

371

Maternal syntabulin is required for dorsal axis formation and is a germ plasm component in Xenopus  

E-print Network

addressed here in Xenopus laevis. in situ hybridization of syntabulin mRNA was carried out at different. This developmental event has been extensively studied in Amphibians, particularly in the frog Xenopus laevisMaternal syntabulin is required for dorsal axis formation and is a germ plasm component in Xenopus

De Robertis, Eddy M.

372

Pathogenesis of PCV2a and PCV2b virus in germ-free pigs  

Technology Transfer Automated Retrieval System (TEKTRAN)

Genetic analysis of porcine circovirus type 2 (PCV2) reveals 2 subgroups that will be referred to as PCV2a and PCV2b representing the North American and European prototypes respectfully. This paper summarizes 3 studies comparing the pathogenesis of 2a and 2b viruses in germ-free pigs. In this PCV2...

373

Sex chromosome inactivation in germ cells: emerging roles of DNA damage response pathways  

E-print Network

REVIEW Sex chromosome inactivation in germ cells: emerging roles of DNA damage response pathways / Accepted: 13 February 2012 / Published online: 2 March 2012 Ã? Springer Basel AG 2012 Abstract Sex. Recent progress has revealed the underlying mechanisms of sex chromosome inactivation in male meiosis

Dean, Matthew D.

374

Regulation of sex chromosome constitution of somatic and germ cells in the wood lemming  

E-print Network

Regulation of sex chromosome constitution of somatic and germ cells in the wood lemming A. GROPP K displays certain peculiar features. (a) The sex ratio shows a prevalence of females, and some females produce only female offspring. (b) A conside- rable proportion of the females has XY sex chromosomes

Paris-Sud XI, Université de

375

INTRODUCTION The primordial germ cells in Xenopus are thought to be  

E-print Network

-like particles (or germinal granules), containing ribosomes, RNA, cytoskeleton and clusters of mitochondria (Czolowska, 1972). Similar structures appear in Drosophila pole plasm (Mahowald, 1968) and C. elegans P-granules (Strome and Wood, 1982), suggesting an evolutionary conservation of cytoplasmic germ cell specification

376

Origin and Development of the Germ Line in Sea Stars Gary M. Wessel,1  

E-print Network

in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system of Echinoderms. But morphology in the order is greatly diverse; some adults have upwards of dozens of arms (e with a backbone, the community is more often referring to them as sea stars, a nomenclature parallel to other some

Wessel, Gary M.

377

Using germ-line genetic variation to investigate and treat cancer  

Microsoft Academic Search

For many years, there has been spirited debate as to the relative importance of environmental and genetic factors in the pathogenesis of cancer. Current efforts to annotate the human genome for germ-line genetic variants should establish the foundation for dissecting the contribution of genetics to the risk for cancer susceptibility. Population-based studies should be conducted to determine the influence of

Sharon A. Savage; Stephen J. Chanock

2004-01-01

378

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer  

PubMed Central

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25493378

Selle, F.; Gligorov, J.; Richard, S.; Khalil, A.; Alexandre, I.; Avenin, D.; Provent, S.; Soares, D.G.; Lotz, J.P.

2014-01-01

379

Increased mortality rates in young and middle-aged patients with malignant germ cell tumours  

Microsoft Academic Search

Cisplatin-based chemotherapy of malignant germ cell tumours (MGCT) has been reported to increase the risk of cardiovascular morbidity. A high incidence of second nongerm cell malignancies is well documented in MGCT survivors. The death risk due to these conditions is, however, more unknown in MGCT patients. Standard mortality rates (SMRs) were established in 3378 Norwegian MGCT patients treated from 1962

S D Fosså; N Aass; S Harvei; S Tretli

2004-01-01

380

ANEUPLOIDIES AND MICRONUCLEI IN THE GERM CELLS OF MALE MICE OF ADVANCED AGE  

EPA Science Inventory

The objective of this research was to determine whether the frequencies of chromosomally defective germ cells increased with age in male laboratory mice. wo types of chromosomal abnormalities were characterized: (1) testicular spermatid aneuploidy (TSA) as measured by a new metho...

381

Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring ( Gallus gallus domesticus)  

Microsoft Academic Search

Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring (Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7

Zhenming Zhou; Zandong Li

2011-01-01

382

Expression of Germ Cell Nuclear Factor (GCNF) by Ovarian Cancer Cell Lines  

Microsoft Academic Search

Ovarian cancer is the fifth most common cancer (neoplasm) among women and the third most common gynecological cancer behind endometrial and cervical cancer (1). Epithelial ovarian cancer (EOC) represents ~90% of all ovarian cancers. Recently, we have observed the novel expression of the nuclear receptor, the germ cell nuclear factor (GCNF) in several ovarian cancer cell lines. This is noteworthy

Sowmya Srikanthan; Jeffrey V. May

383

Germ Plasm: Protein Degradation in Caroline A. Spike and Susan Strome  

E-print Network

is a specialized cytoplasm that is physically segregated to the germline cells during early embryogenesis. Recent in somatic lineages by a ubiquitin ligase that targets germ plasm proteins for degradation. The embryonic somatic blastomere -- AB, EMS, C and D -- and a smaller germline blastomere -- P1, P2, P3 and P4. Each

Strome, Susan

384

Evaluation of Elevated Dietary Corn Fiber from Corn Germ Meal in Growing Female Pigs  

Technology Transfer Automated Retrieval System (TEKTRAN)

To evaluate the effects of high dietary corn fiber on growth and metabolic measures, female pigs (n= 48; initial body weight of 30.8 kg) were fed diets containing 0 to 38.6% solvent-extracted corn germ meal for 28 days. Increasing the level of dietary corn fiber had no impact on average daily gain o...

385

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer.  

PubMed

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25493378

Selle, F; Gligorov, J; Richard, S; Khalil, A; Alexandre, I; Avenin, D; Provent, S; Soares, D G; Lotz, J P

2015-01-01

386

Regulation and function of tailless in the long germ wasp Nasonia vitripennis  

Microsoft Academic Search

In the long germ insect Drosophila, the gene tailless acts to pattern the terminal regions of the embryo. Loss of function of this gene results in the deletion of the anterior and posterior terminal structures and the eighth abdominal segment. Drosophila tailless is activated by the maternal terminal system through Torso signaling at both poles of the embryo, with additional

Jeremy A. Lynch; Eugenia C. Olesnicky; Claude Desplan

2006-01-01

387

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer.  

PubMed

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25372715

Selle, F; Gligorov, J; Richard, S; Khalil, A; Alexandre, I; Avenin, D; Provent, S; Soares, D G; Lotz, J P

2014-11-01

388

Molecular Genetic Parameters in Pathogenesis and Prognosis of Testicular Germ Cell Tumors  

Microsoft Academic Search

Aim of this review article was to critically analyze the recently described cytogenetic and molecular markers for testicular germ cell tumors with regard to their clinical utility. The isochromosme i(12p) represents the most common and characteristic cytogenetic finding which already appears in testicular carcinoma in situ. A number of proto–oncogenes (cyclin D and PTHLH) as well as putative tumor suppressor

A. Heidenreich; S. Srivastava; J. W. Moul; R. Hofmann; C. R. Chapple; K. Fujikawa; S. Fukuzawa

2000-01-01

389

Transposon silencing in the Caenorhabditis elegans germ line by natural RNAi  

Microsoft Academic Search

Transposable elements are stretches of DNA that can move and multiply within the genome of an organism. The Caenorhabditis elegans genome contains multiple Tc1 transposons that jump in somatic cells, but are silenced in the germ line. Many mutants that have lost this silencing have also lost the ability to execute RNA interference (RNAi), a process whereby genes are suppressed

Titia Sijen; Ronald H. A. Plasterk

2003-01-01

390

Chub mackerel gonads support colonization, survival, and proliferation of intraperitoneally transplanted xenogenic germ cells.  

PubMed

The production of xenogenic gametes from large-bodied, commercially important marine fish species in closely related smaller host fish species with short generation times may enable rapid and simple seed production of the target species. As a first step toward this goal, we assessed the suitability of chub mackerel, Scomber japonicus, as a small-bodied recipient species for xenogenic spermatogonial transplantation. Histological observation of the early gonadal development of chub mackerel larvae and transplantation of fluorescent-labeled spermatogonia from Nibe croaker, Nibea mitsukurii, revealed that 5.3-mm chub mackerel larvae were suitable recipients for successful transplantation. Intraperitoneally transplanted xenogenic spermatogonia efficiently colonized the gonads of these recipient larvae, and donor-derived Nibe croaker germ cells proliferated rapidly soon after colonization. Moreover, gonadal soma-derived growth factor (gsdf) mRNA, a gonadal somatic cell marker, was expressed in recipient-derived cells surrounding the incorporated donor-derived germ cells, suggesting that donor-derived germ cells had settled at an appropriate location in the recipient gonad. Our data show that xenogenic spermatogonial transplantation was successful in chub mackerel and that the somatic microenvironment of the chub mackerel gonad can support the colonization, survival, and proliferation of intraperitoneally transplanted xenogenic germ cells derived from a donor species of a different taxonomic family. PMID:20089885

Yazawa, Ryosuke; Takeuchi, Yutaka; Higuchi, Kentaro; Yatabe, Takashi; Kabeya, Naoki; Yoshizaki, Goro

2010-05-01

391

Localization to Xq27 of a susceptibility gene for testicular germ-cell tumours  

Microsoft Academic Search

Testicular germ-cell tumours (TGCT) affect 1 in 500 men and are the most common cancer in males aged 15–40 in Western European populations. The incidence of TGCT has risen dramatically over the last century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT (ref. 7) and a family history of the

Elizabeth A. Rapley; Gillian P. Crockford; Dawn Teare; Patrick Biggs; Sheila Seal; Rita Barfoot; Sandra Edwards; Rifat Hamoudi; Ketil Heimdal; Sophie D. Fosså; Kathy Tucker; Jenny Donald; Felicity Collins; Michael Friedlander; David Hogg; Paul Goss; Axel Heidenreich; Wilma Ormiston; Peter A. Daly; David Forman; Timothy D. Oliver; Michael Leahy; Robert Huddart; Colin S. Cooper; Julia G. Bodmer; Douglas F. Easton; D. Timothy Bishop; Michael R. Stratton

2000-01-01

392

Module title: GERMAN Accelerated Language stages 1-2 Module code: GERM9040  

E-print Network

Module title: GERMAN Accelerated Language stages 1-2 Module code: GERM9040 1. School (and/French and German as well as Spanish/French and German (Linguistic Studies) with German studied ab initio 6 in a variety of genres (including emails, newspapers, textbooks and literature) without too much effort

Anderson, Jim

393

In germ cells of mouse embryonic ovaries, the decision to enter meiosis precedes premeiotic DNA replication  

E-print Network

In germ cells of mouse embryonic ovaries, the decision to enter meiosis precedes premeiotic DNA Carpenter2, Dirk G de Rooij3 & David C Page1,2 The transition from mitosis to meiosis is a defining juncture in the life cycle of sexually reproducing organisms. In yeast, the decision to enter meiosis is made before

Carpenter, Anne E.

394

Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice  

Microsoft Academic Search

Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice, and that the effect increases with advancing maternal age. Analysis of

Shawn Leland; Prabakaran Nagarajan; Aris Polyzos; Sharon Thomas; George Samaan; Robert Donnell; Francesco Marchetti; Sundaresan Venkatachalam

2009-01-01

395

Clean and DisinfectClean and DisinfectClean and Disinfect Germ Fighting 101  

E-print Network

Clean and DisinfectClean and DisinfectClean and Disinfect Germ Fighting 101 Non-Porous Surfaces A dishwashing machine can substitute in cleaning and disinfecting of toys and dishes 1. Clean surface with a mild detergent to remove visible signs of dirt 2. Then disinfect with: · EPA registered disinfectant

396

Transcriptional Signatures in Response to Wheat Germ Agglutinin and Starvation in Drosophila melanogaster Larval Midgut  

Technology Transfer Automated Retrieval System (TEKTRAN)

One function of plant lectins such as wheat germ agglutinin (WGA) is to serve as defenses against herbivorous insects. The midgut is one critical site affected by dietary lectins. We observed marked cellular, structural, and gene expression changes in the midguts of Drosophila melanogaster third-i...

397

Determination of cancer risk associated with germ line BRCA1 missense variants by functional analysis  

Microsoft Academic Search

Germ line inactivating mutations in BRCA1 confer suscepti- bility for breast and ovarian cancer. However, the relevance of the many missense changes in the gene for which the effect on protein function is unknown remains unclear. Determi- nation of which variants are causally associated with cancer is important for assessment of individual risk. We used a functional assay that measures

Marcelo A. Carvalho; Sylvia M. Marsillac; Rachel Karchin; Siranoush Manoukian; Scott Grist; Ramona F. Swaby; Turan P. Urmenyi; Edson Rondinelli; Rosane Silva; Luis Gayol; Lisa Baumbach; Rebecca Sutphen; J. L. PICKARD-RRZOSOWICZ; Katherine L. Nathanson; Andrej Sali; David Goldgar; Fergus J. Couch; Paolo Radice; Alvaro N. A. Monteiro

2007-01-01

398

Angiotensin I Converting enzyme inhibitory peptides from commercial wet- and dry-milled corn germ  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bioprocesses were developed to enhance the value of proteins from de-oiled corn germ. Proteins were hydrolyzed with trypsin, GC106, Flavourzyme or thermolysin in order to free the bioactive peptide sequences. Protein hydrolysis, at an enzyme to substrate ratio of 1:250, was greater for wet- than d...

399

DAZL limits pluripotency, differentiation, and apoptosis in developing primordial germ cells.  

PubMed

The scarcity of primordial germ cells (PGCs) in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade. PMID:25418731

Chen, Hsu-Hsin; Welling, Maaike; Bloch, Donald B; Muñoz, Javier; Mientjes, Edwin; Chen, Xinjie; Tramp, Cody; Wu, Jie; Yabuuchi, Akiko; Chou, Yu-Fen; Buecker, Christa; Krainer, Adrian; Willemsen, Rob; Heck, Albert J; Geijsen, Niels

2014-11-11

400

DAZL Limits Pluripotency, Differentiation, and Apoptosis in Developing Primordial Germ Cells  

PubMed Central

Summary The scarcity of primordial germ cells (PGCs) in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade. PMID:25418731

Chen, Hsu-Hsin; Welling, Maaike; Bloch, Donald B.; Muñoz, Javier; Mientjes, Edwin; Chen, Xinjie; Tramp, Cody; Wu, Jie; Yabuuchi, Akiko; Chou, Yu-Fen; Buecker, Christa; Krainer, Adrian; Willemsen, Rob; Heck, Albert J.; Geijsen, Niels

2014-01-01

401

February 1, 2004 Page 1 of 2 Stopping Germs at Home, Work and School  

E-print Network

infection of concern in schools -- nearly 22 million schools days are lost each year to the common cold, the common cold, and other illnesses. See Other Resources and Posters on this Stop the Spread of Germs site and Bloomfield, 1989) · Nearly 22 million school days are lost annually due to the common cold alone. (CDC, 1996

Burke, Peter

402

Composition and oxidative stability of crude oil extracts of corn germ and distillers grains  

Microsoft Academic Search

The fatty acid composition, Acid Value, and the content and composition of tocopherols, tocotrienols, carotenoids, phytosterols, and steryl ferulates were determined in corn germ oil and four post-fermentation corn oils from the ethanol dry grind process. The oxidative stability index at 110°C was determined for the five oils, and four oils were compared for their stability during storage at 40°C

Jill K. Winkler-Moser; Lotta Breyer

2011-01-01

403

Inter-Regional, Epidemiological Study of Childhood Cancer (IRESCC): case-control study in children with germ cell tumors  

SciTech Connect

In 1980-1983 members of IRESCC interviewed parents of 555 children with newly diagnosed cancer on topics of possible etiological significance. Identical questions were asked of the parents of 1100 control children chosen from hospital admissions and general practitioner lists. Medical information was confirmed whenever possible by cross-checking with NHS records. Data for the 41 children with germ cell tumors and their 82 controls are reported here. The cases had more major congenital malformations than controls, including one neural tube defect. More case than control mothers and fathers reported occupational exposure to chemicals. Nine close relatives of cases had multiple primary tumors, which were often benign or of low-grade malignancy, compared with 1 hospital control and 3 general practitioner control relatives. Cases and controls differed with respect to birth weight and paternal age. No case-control differences were shown for: birth rank, maternal age, chronic illnesses and smoking, mothers reproductive histories and oral contraceptive usage. In index pregnancies there were no case-control differences for maternal illness, infections, alcohol intake and X-ray and ultrasound exposure. There was no difference between cases and controls for the frequency of twinning the families.

Johnston, H.E.; Mann, J.R.; Williams, J.; Waterhouse, J.A.; Birch, J.M.; Cartwright, R.A.; Draper, G.J.; Hartley, A.L.; McKinney, P.A.; Hopton, P.A.

1986-05-01

404

Germ-line mutation analysis in patients with multiple endocrine neoplasia type 1 and related disorders.  

PubMed Central

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant syndrome predisposing to tumors of the parathyroid, endocrine pancreas, anterior pituitary, adrenal glands, and diffuse neuroendocrine tissues. The MEN1 gene has been assigned, by linkage analysis and loss of heterozygosity, to chromosome 11q13 and recently has been identified by positional cloning. In this study, a total of 84 families and/or isolated patients with either MEN1 or MEN1-related inherited endocrine tumors were screened for MEN1 germ-line mutations, by heteroduplex and sequence analysis of the MEN1 gene-coding region and untranslated exon 1. Germ-line MEN1 alterations were identified in 47/54 (87%) MEN1 families, in 9/11 (82%) isolated MEN1 patients, and in only 6/19 (31.5%) atypical MEN1-related inherited cases. We characterized 52 distinct mutations in a total of 62 MEN1 germ-line alterations. Thirty-five of the 52 mutations were frameshifts and nonsense mutations predicted to encode for a truncated MEN1 protein. We identified eight missense mutations and five in-frame deletions over the entire coding sequence. Six mutations were observed more than once in familial MEN1. Haplotype analysis in families with identical mutations indicate that these occurrences reflected mainly independent mutational events. No MEN1 germ-line mutations were found in 7/54 (13%) MEN1 families, in 2/11 (18%) isolated MEN1 cases, in 13/19 (68. 5%) MEN1-related cases, and in a kindred with familial isolated hyperparathyroidism. Two hundred twenty gene carriers (167 affected and 53 unaffected) were identified. No evidence of genotype-phenotype correlation was found. Age-related penetrance was estimated to be >95% at age >30 years. Our results add to the diversity of MEN1 germ-line mutations and provide new tools in genetic screening of MEN1 and clinically related cases. PMID:9683585

Giraud, S; Zhang, C X; Serova-Sinilnikova, O; Wautot, V; Salandre, J; Buisson, N; Waterlot, C; Bauters, C; Porchet, N; Aubert, J P; Emy, P; Cadiot, G; Delemer, B; Chabre, O; Niccoli, P; Leprat, F; Duron, F; Emperauger, B; Cougard, P; Goudet, P; Sarfati, E; Riou, J P; Guichard, S; Rodier, M; Meyrier, A; Caron, P; Vantyghem, M C; Assayag, M; Peix, J L; Pugeat, M; Rohmer, V; Vallotton, M; Lenoir, G; Gaudray, P; Proye, C; Conte-Devolx, B; Chanson, P; Shugart, Y Y; Goldgar, D; Murat, A; Calender, A

1998-01-01

405

Germ cell specification and ovary structure in the rotifer Brachionus plicatilis  

PubMed Central

Background The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'). Here we investigate the specification and development of the germ cells in the rotifer Brachionus plicatilis, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the Brachionus homologues of the conserved germ cell markers vasa and nanos, and examining their expression using in situ hybridization. Results Bpvasa and Bpnos RNA expression have very similar distributions in the Brachionus ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. Bpvas RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. Bpnos RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, Bpnos RNA expression is re-activated, located in a subset of posterior cells similar to those expressing Bpvas at the same stage. Conclusions The observed expression of vasa and nanos in the developing B. plicatilis embryo implies an epigenetic origin of primordial germ cells in Rotifer. PMID:20849649

2010-01-01

406

DDX4 (VASA) is conserved in germ cell development in marsupials and monotremes.  

PubMed

DDX4 (VASA) is an RNA helicase expressed in the germ cells of all animals. To gain greater insight into the role of this gene in mammalian germ cell development, we characterized DDX4 in both a marsupial (the tammar wallaby) and a monotreme (the platypus). DDX4 is highly conserved between eutherian, marsupial, and monotreme mammals. DDX4 protein is absent from tammar fetal germ cells but is present from Day 1 postpartum in both sexes. The distribution of DDX4 protein during oogenesis and spermatogenesis in the tammar is similar to eutherians. Female tammar germ cells contain DDX4 protein throughout all stages of postnatal oogenesis. In males, DDX4 is in gonocytes, and during spermatogenesis it is present in spermatocytes and round spermatids. A similar distribution of DDX4 occurs in the platypus during spermatogenesis. There are several DDX4 isoforms in the tammar, resulting from both pre- and posttranslational modifications. DDX4 in marsupials and monotremes has multiple splice variants and polyadenylation motifs. Using in silico analyses of genomic databases, we found that these previously unreported splice variants also occur in eutherians. In addition, several elements implicated in the control of Ddx4 expression in the mouse, including RGG (arginine-glycine-glycine) and dimethylation of arginine motifs and CpG islands within the Ddx4 promoter, are also highly conserved. Collectively these data suggest that DDX4 is essential for the regulation of germ cell proliferation and differentiation across all three extant mammalian groups-eutherians, marsupials, and monotremes. PMID:21653890

Hickford, Danielle E; Frankenberg, Stephen; Pask, Andrew J; Shaw, Geoff; Renfree, Marilyn B

2011-10-01

407

Pituitary blastoma: a pathognomonic feature of germ-line DICER1 mutations  

PubMed Central

Individuals harboring germ-line DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 Syndrome or pleuropulmonary blastoma-familial tumor and dysplasia syndrome [online Mendelian inheritance in man (OMIM) #601200]. In addition, specific somatic mutations in the DICER1 RNase III catalytic domain have been identified in several DICER1-associated tumor types. Pituitary blastoma (PitB) was identified as a distinct entity in 2008, and is a very rare, potentially lethal early childhood tumor of the pituitary gland. Since the discovery by our team of an inherited mutation in DICER1 in a child with PitB in 2011, we have identified 12 additional PitB cases. We aimed to determine the contribution of germ-line and somatic DICER1 mutations to PitB. We hypothesized that PitB is a pathognomonic feature of a germ-line DICER1 mutation and that each PitB will harbor a second somatic mutation in DICER1. Lymphocyte or saliva DNA samples ascertained from ten infants with PitB were screened and nine were found to harbor a heterozygous germ-line DICER1 mutation. We identified additional DICER1 mutations in nine of ten tested PitB tumor samples, eight of which were confirmed to be somatic in origin. Seven of these mutations occurred within the RNase IIIb catalytic domain, a domain essential to the generation of 5p miRNAs from the 5? arm of miRNA-precursors. Germ-line DICER1 mutations are a major contributor to PitB. Second somatic DICER1 “hits” occurring within the RNase IIIb domain also appear to be critical in PitB pathogenesis. PMID:24839956

de Kock, Leanne; Sabbaghian, Nelly; Plourde, François; Srivastava, Archana; Weber, Evan; Soglio, Dorothée Bouron-Dal; Hamel, Nancy; Choi, Joon Hyuk; Park, Sung-Hye; Deal, Cheri L.; Kelsey, Megan M.; Dishop, Megan K.; Esbenshade, Adam; Kuttesch, John F.; Jacques, Thomas S.; Perry, Arie; Leichter, Heinz; Maeder, Philippe; Brundler, Marie-Anne; Warner, Justin; Neal, James; Zacharin, Margaret; Korbonits, Márta; Cole, Trevor; Traunecker, Heidi; McLean, Thomas W.; Rotondo, Fabio; Lepage, Pierre; Albrecht, Steffen; Horvath, Eva; Kovacs, Kalman; Priest, John R.; Foulkes, William D.

2014-01-01

408

Dynamic changes in DNA modification states during late gestation male germ line development in the rat  

PubMed Central

Background Epigenetic reprogramming of fetal germ cells involves the genome-wide erasure and subsequent re-establishment of DNA methylation. Mouse studies indicate that DNA demethylation may be initiated at embryonic day (e) 8 and completed between e11.5 and e12.5. In the male germline, DNA remethylation begins around e15 and continues for the remainder of gestation whilst this process occurs postnatally in female germ cells. Although 5-methylcytosine (5mC) dynamics have been extensively characterised, a role for the more recently described DNA modifications (5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC)) remains unclear. Moreover, the extent to which the developmental dynamics of 5mC reprogramming is conserved across species remains largely undetermined. Here, we sought to describe this process during late gestation in the male rat. Results Using immunofluorescence, we demonstrate that 5mC is re-established between e18.5 and e21.5 in the rat, subsequent to loss of 5hmC, 5fC and 5caC, which are present in germ cells between e14.5 and e16.5. All of the evaluated DNA methyl forms were expressed in testicular somatic cells throughout late gestation. 5fC and 5caC can potentially be excised through Thymine DNA Glycosylase (TDG) and repaired by the base excision repair (BER) pathway, implicating 5mC oxidation in active DNA demethylation. In support of this potential mechanism, we show that TDG expression is coincident with the presence of 5hmC, 5fC and 5caC in male germ cell development. Conclusion The developmental dependent changes in germ cell DNA methylation patterns suggest that they are linked with key stages of male rat germline progression. PMID:25225576

2014-01-01

409

Propagation of human germ stem cells in long-term culture  

PubMed Central

Background: Spermatogonial stem cells (SSCs), a subset of undifferentiated type A spermatogonia, are the foundation of complex process of spermatogenesis and could be propagated in vitro culture conditions for long time for germ cell transplantation and fertility preservation. Objective: The aim of this study was in vitro propagation of human spermatogonial stem cells (SSCs) and improvement of presence of human Germ Stem Cells (hGSCs) were assessed by specific markers POU domain, class 5, transcription factor 1 (POU5F1), also known as Octamer-binding transcription factor 4 (Oct-4) and PLZF (Promyelocytic leukaemia zinc finger protein). Materials and Methods: Human testicular cells were isolated by enzymatic digestion (Collagenase IV and Trypsin). Germ cells were cultured in Stem-Pro 34 media supplemented by growth factors such as glial cell line-derived neurotrophic factor, basic fibroblast growth factor, epidermal growth factor and leukemia inhibitory factor to support self-renewal divisions. Germline stem cell clusters were passaged and expanded every week. Immunofluorecent study was accomplished by Anti-Oct4 antibody through the culture. The spermatogonial stem cells genes expression, PLZF, was studied in testis tissue and germ stem cells entire the culture. Results: hGSCs clusters from a brain dead patient developed in testicular cell culture and then cultured and propagated up to 6 weeks. During the culture Oct4 were a specific marker for identification of hGSCs in testis tissue. Expression of PLZF was applied on RNA level in germ stem cells. Conclusion: hGSCs indicated by SSCs specific marker can be cultured and propagated for long-term in vitro conditions. This article extracted from Ph.D. Thesis. (Zeinab Piravar) PMID:24639790

Akhondi, Mohammad Mehdi; Mohazzab, Arash; Jeddi-Tehrani, Mahmood; Sadeghi, Mohammad Reza; Eidi, Akram; Khodadadi, Abbas; Piravar, Zeinab

2013-01-01

410

Effects of Lactobacillus kefiranofaciens M1 Isolated from Kefir Grains on Germ-Free Mice  

PubMed Central

Lactobacillus kefiranofaciens M1 is a novel probiotic strain that was isolated from kefir grains. Previously, we have demonstrated the immunoregulatory, anti-allergic, anti-asthmatic and anti-colitis abilities of L. kefiranofaciens M1 in a number of in-vitro and in-vivo experiments. However, whether the effects of L. kefiranofaciens M1 are elicited directly on the host or act by regulating the host's microbiota remains unknown. A number of studies have used germ-free or gnotobiotic animals to investigate the relationship between probiotics and colitis; therefore the aim of this study was to investigate the effects of L. kefiranofaciens M1 on germ-free mice. Such an approach should help in determining the direct effects of L. kefiranofaciens M1 on the host itself. Four-week-old female germ-free mice were inoculated intragastrically with 2×108 CFU/mouse L. kefiranofaciens M1 once or at 2-day intervals for 14 days. Bacterial colonization, the Th1/Th2 cytokine profile of the mice's splenocytes and the anti-colitis effect of L. kefiranofaciens M1 were investigated. The strongest response in terms of splenic Th1 cytokine IFN-? and IL-12 production upon TLR activation was detected in the continuous treatment group when comparing to the single inoculation group and the germ-free control. In addition, continuous inoculation with L. kefiranofaciens M1 was found to ameliorate the symptoms of DSS-induced colitis in germ-free mice. However, L. kefiranofaciens M1 failed to colonize the host. Thus it would seem that L. kefiranofaciens M1 is likely to act directly on the host and not be involved in microbiota regulation. PMID:24244362

Chen, Yen-Po; Chen, Ming-Ju

2013-01-01

411

Hyperproliferation of mitotically active germ cells due to defective anti-Müllerian hormone signaling mediates sex reversal in medaka.  

PubMed

The function of AMH (Anti-Müllerian hormone), a phylogenetically ancient member of the TGF? family of proteins, in lower vertebrates is largely unknown. Previously, we have shown that the gene encoding the type II anti-Müllerian hormone receptor, amhrII, is responsible for excessive germ cell proliferation and male-to-female sex reversal in the medaka hotei mutant. In this study, functional analyses in cultured cells and of other amhrII mutant alleles indicate that lack of AMH signaling causes the hotei phenotype. BrdU incorporation experiments identified the existence of both quiescent and mitotically active germ cells among the self-renewing, type I population of germ cells in the developing gonad. AMH signaling acts in supporting cells to promote the proliferation of mitotically active germ cells but does not trigger quiescent germ cells to proliferate in the developing gonad. Furthermore, we show that the male-to-female sex reversal phenotype in hotei mutants is not a direct consequence of AMH signaling in supporting cells, but is instead mediated by germ cells. Our data demonstrate that interfollicular AMH signaling regulates proliferation at a specific stage of germ cell development, and that this regulation is crucial for the proper manifestation of gonadal sex directed by sex determination genes. PMID:22627284

Nakamura, Shuhei; Watakabe, Ikuko; Nishimura, Toshiya; Picard, Jean-Yves; Toyoda, Atsushi; Taniguchi, Yoshihito; di Clemente, Nathalie; Tanaka, Minoru

2012-07-01

412

Activation of the germ-cell potential of human bone marrow-derived cells by a chemical carcinogen  

PubMed Central

Embryonic/germ cell traits are common in malignant tumors and are thought to be involved in malignant tumor behaviors. The reasons why tumors show strong embryonic/germline traits (displaced germ cells or gametogenic programming reactivation) are controversial. Here, we show that a chemical carcinogen, 3-methyl-cholanthrene (3-MCA), can trigger the germ-cell potential of human bone marrow-derived cells (hBMDCs). 3-MCA promoted the generation of germ cell-like cells from induced hBMDCs that had undergone malignant transformation, whereas similar results were not observed in the parallel hBMDC culture at the same time point. The malignant transformed hBMDCs spontaneously and more efficiently generated into germ cell-like cells even at the single-cell level. The germ cell-like cells from induced hBMDCs were similar to natural germ cells in many aspects, including morphology, gene expression, proliferation, migration, further development, and teratocarcinoma formation. Therefore, our results demonstrate that a chemical carcinogen can reactivate the germline phenotypes of human somatic tissue-derived cells, which might provide a novel idea to tumor biology and therapy. PMID:24998261

Liu, Chunfang; Ma, Zhan; Xu, Songtao; Hou, Jun; Hu, Yao; Yu, Yinglu; Liu, Ruilai; Chen, Zhihong; Lu, Yuan

2014-01-01

413

Primary Hyperoxaluria  

PubMed Central

Primary hyperoxalurias (PH) are inborn errors in the metabolism of glyoxylate and oxalate. PH type 1, the most common form, is an autosomal recessive disorder caused by a deficiency of the liver-specific enzyme alanine, glyoxylate aminotransferase (AGT) resulting in overproduction and excessive urinary excretion of oxalate. Recurrent urolithiasis and nephrocalcinosis are the hallmarks of the disease. As glomerular filtration rate decreases due to progressive renal damage, oxalate accumulates leading to systemic oxalosis. Diagnosis is often delayed and is based on clinical and sonographic findings, urinary oxalate assessment, DNA analysis, and, if necessary, direct AGT activity measurement in liver biopsy tissue. Early initiation of conservative treatment, including high fluid intake, inhibitors of calcium oxalate crystallization, and pyridoxine in responsive cases, can help to maintain renal function in compliant subjects. In end-stage renal disease patients, the best outcomes have been achieved with combined liver-kidney transplantation which corrects the enzyme defect. PMID:21748001

Harambat, Jérôme; Fargue, Sonia; Bacchetta, Justine; Acquaviva, Cécile; Cochat, Pierre

2011-01-01

414

Licensing of gametogenesis, dependent on RNA binding protein DAZL, as a gateway to sexual differentiation of fetal germ cells  

E-print Network

Mammalian oocytes and spermatozoa derive from fetal cells shared by the sexes. These primordial germ cells (PGCs) migrate to the developing somatic gonad, giving rise to oocytes or spermatozoa. These opposing sexual fates ...

Gill, Mark E.

415

Mir-290–295 deficiency in mice results in partially penetrant embryonic lethality and germ cell defects  

PubMed Central

Mir-290 through mir-295 (mir-290–295) is a mammalian-specific microRNA (miRNA) cluster that, in mice, is expressed specifically in early embryos and embryonic germ cells. Here, we show that mir-290–295 plays important roles in embryonic development as indicated by the partially penetrant lethality of mutant embryos. In addition, we show that in surviving mir-290–295-deficient embryos, female but not male fertility is compromised. This impairment in fertility arises from a defect in migrating primordial germ cells and occurs equally in male and female mutant animals. Male mir-290–295?/? mice, due to the extended proliferative lifespan of their germ cells, are able to recover from this initial germ cell loss and are fertile. Female mir-290–295?/? mice are unable to recover and are sterile, due to premature ovarian failure. PMID:21844366

Medeiros, Lea A.; Dennis, Lucas M.; Gill, Mark E.; Houbaviy, Hristo; Markoulaki, Styliani; Fu, Dongdong; White, Amy C.; Kirak, Oktay; Sharp, Phillip A.; Page, David C.; Jaenisch, Rudolf

2011-01-01

416

STAGE-SPECIFIC DAMAGE TO SYNAPTONEMAL COMPLEXES AND METAPHASE CHROMOSOME INDUCED BY X RAYS IN MALE MOUSE GERM CELLS  

EPA Science Inventory

Synaptonemal complexes (SCs) reveal mutagen-induced effects in germ cell meiotic chromosomes. his study was aimed at characterizing relationships between SC and metaphase I chromosome damage following radiation exposure at various stages of spermatogenesis. Male mice were irradia...

417

Identification of a germ-line mutation in the p53 gene in a patient with an intracranial ependymoma  

SciTech Connect

The authors detected a germ-line mutation of the p53 gene in a patient with a malignant ependymoma of the posterior fossa. This mutation, which was found at codon 242, resulted in an amino acid substitution in a highly conserved site of exon 7 of the p53 gene; the same mutation was found in both the germ-line and tumor tissue. This is the most common region of previously described somatic p53 mutations in tumor specimens and of the germ-line p53 mutations in patients with the Li-Fraumeni cancer syndrome. Evaluation of the patient's family revealed several direct maternal and paternal relatives who had died at a young age from different types of cancer. The association of a germ-line p53 mutation with an intracranial malignancy and a strong family history of cancer suggests that p53 gene mutations predispose a person to malignancy and, like retinoblastoma mutations, may be inherited.

Metzger, A.K.; Duyk, G.; Daneshvar, L.; Edwards, M.S.B.; Cogen, P.H. (Univ. of California, San Francisco (United States)); Sheffield, V.C. (Univ. of Iowa, Iowa City (United States))

1991-09-01

418

Maternal loss of miRNAs leads to increased variance in primordial germ cell numbers in Drosophila melanogaster.  

PubMed

MicroRNAs (miRNAs) are posttranscriptional regulators of gene expression that may act as buffering agents to stabilize gene-regulatory networks. Here, we identify two miRNAs that are maternally required for normal embryonic primordial germ cell development in Drosophila melanogaster. Embryos derived from miR-969 and miR-9c mutant mothers had, on average, reduced germ cell numbers. Intriguingly, this reduction correlated with an increase in the variance of this quantitative phenotypic trait. Analysis of an independent set of maternal mutant genotypes suggests that reduction of germ cell number need not lead to increased variance. Our observations are consistent with the hypothesis that miR-969 and miR-9c contribute to stabilizing the processes that control germ number, supporting phenotypic robustness. PMID:23893743

Kugler, Jan-Michael; Chen, Ya-Wen; Weng, Ruifen; Cohen, Stephen M

2013-09-01

419

Primary production off Southern California relative to surface layer carbon budgets: A component of the California Basins Study, CaBS. Final report, [1 June 1989--14 November 1991  

SciTech Connect

This study started on 1 June 1989 and ended 14 November 1991. Two moored in situ natural fluorometers were deployed in January 1990 to collect bio-optical data for one year, making ground truth measurements around the mooring during 4 cruises. This one-year time series would investigate how the short-term physical forcing aliases the long-term primary production record such that the apparent, larger interannual variability in the record is in reality ``noise`` due to short-term fluctuations in the rate of nutrient input to the euphotic zone. These continuous measurements from moored bio-optical instruments would also allow better estimates of the mean and variance in primary production in these waters than has previously been available from shipboard measurements, as well as, phytoplankton response to short-term physical events. Ancillary measurements that were made were: (1) characterization of the apparent and inherent optical properties, (2) photosynthetic pigment distributions using both HPLC and standard fluorometric methods, (3) carbon, hydrogen and nitrogen content of suspended particulate matter, (4) primary production using conventional {sup 14}C methods from simulated in situ experiments.

Trees, C.C.

1994-04-22

420

A genome-wide association study of testicular germ cell tumor  

PubMed Central

We conducted a genome-wide association study for testicular germ cell tumor (TGCT), genotyping 307,666 SNPs in 730 cases and 1,435 controls from the UK and replicating associations in a further 571 cases and 1,806 controls. We found strong evidence for susceptibility loci on chromosome 5 (per allele OR = 1.37 (95% CI = 1.19–1.58), P = 3 × 10?13), chromosome 6 (OR = 1.50 (95% = CI = 1.28–1.75), P = 10?13) and chromosome 12 (OR = 2.55 (95% CI = 2.05–3.19), P = 10?31). KITLG, encoding the ligand for the receptor tyrosine kinase KIT, which has previously been implicated in the pathogenesis of TGCT and the biology of germ cells, may explain the association on chromosome 12. PMID:19483681

Rapley, Elizabeth A; Turnbull, Clare; Olama, Ali Amin Al; Dermitzakis, Emmanouil T; Linger, Rachel; Huddart, Robert A; Renwick, Anthony; Hughes, Deborah; Hines, Sarah; Seal, Sheila; Morrison, Jonathan; Nsengimana, Jeremie; Deloukas, Panagiotis; Rahman, Nazneen; Bishop, D Timothy; Easton, Douglas F; Stratton, Michael R

2010-01-01

421

A genome-wide association study of testicular germ cell tumor.  

PubMed

We conducted a genome-wide association study for testicular germ cell tumor (TGCT), genotyping 307,666 SNPs in 730 cases and 1,435 controls from the UK and replicating associations in a further 571 cases and 1,806 controls. We found strong evidence for susceptibility loci on chromosome 5 (per allele OR = 1.37 (95% CI = 1.19-1.58), P = 3 x 10(-13)), chromosome 6 (OR = 1.50 (95% CI = 1.28-1.75), P = 10(-13)) and chromosome 12 (OR = 2.55 (95% CI = 2.05-3.19), P = 10(-31)). KITLG, encoding the ligand for the receptor tyrosine kinase KIT, which has previously been implicated in the pathogenesis of TGCT and the biology of germ cells, may explain the association on chromosome 12. PMID:19483681

Rapley, Elizabeth A; Turnbull, Clare; Al Olama, Ali Amin; Dermitzakis, Emmanouil T; Linger, Rachel; Huddart, Robert A; Renwick, Anthony; Hughes, Deborah; Hines, Sarah; Seal, Sheila; Morrison, Jonathan; Nsengimana, Jeremie; Deloukas, Panagiotis; Rahman, Nazneen; Bishop, D Timothy; Easton, Douglas F; Stratton, Michael R

2009-07-01

422

Early Depletion of Primordial Germ Cells in Zebrafish Promotes Testis Formation  

PubMed Central

Summary As complete absence of germ cells leads to sterile males in zebrafish, we explored the relationship between primordial germ cell (PGC) number and sexual development. Our results revealed dimorphic proliferation of PGCs in the early zebrafish larvae, marking the beginning of sexual differentiation. We applied morpholino-based gene knockdown and cell transplantation strategies to demonstrate that a threshold number of PGCs is required for the stability of ovarian fate. Using histology and transcriptomic analyses, we determined that zebrafish gonads are in a meiotic ovarian stage at 14 days postfertilization and identified signaling pathways supporting meiotic oocyte differentiation and eventual female fate. The development of PGC-depleted gonads appears to be restrained and delayed, suggesting that PGC number may directly regulate the variability and length of gonadal transformation and testicular differentiation in zebrafish. We propose that gonadal transformation may function as a developmental buffering mechanism to ensure the reproductive outcome. PMID:25434820

Tzung, Keh-Weei; Goto, Rie; Saju, Jolly M.; Sreenivasan, Rajini; Saito, Taiju; Arai, Katsutoshi; Yamaha, Etsuro; Hossain, Mohammad Sorowar; Calvert, Meredith E.K.; Orbán, László

2014-01-01

423

Functional salivary gland regeneration by transplantation of a bioengineered organ germ  

PubMed Central

Salivary gland hypofunction, also known as xerostomia, occurs as a result of radiation therapy for head cancer, Sjögren’s syndrome or aging, and can cause a variety of critical oral health issues, including dental decay, bacterial infection, mastication dysfunction, swallowing dysfunction and reduced quality of life. Here we demonstrate the full functional regeneration of a salivary gland that reproduces the morphogenesis induced by reciprocal epithelial and mesenchymal interactions through the orthotopic transplantation of a bioengineered salivary gland germ as a regenerative organ replacement therapy. The bioengineered germ develops into a mature gland through acinar formations with a myoepithelium and innervation. The bioengineered submandibular gland produces saliva in response to the administration of pilocarpine and gustatory stimulation by citrate, protects against oral bacterial infection and restores normal swallowing in a salivary gland-defective mouse model. This study thus provides a proof-of-concept for bioengineered salivary gland regeneration as a potential treatment of xerostomia. PMID:24084982

Ogawa, Miho; Oshima, Masamitsu; Imamura, Aya; Sekine, Yurie; Ishida, Kentaro; Yamashita, Kentaro; Nakajima, Kei; Hirayama, Masatoshi; Tachikawa, Tetsuhiko; Tsuji, Takashi

2013-01-01

424

Aging is a deprivation syndrome driven by a germ-soma conflict.  

PubMed

Evolution through natural selection can be described as driven by a perpetual conflict of individuals competing for limited resources. Recently, I postulated that the shortage of resources godfathered the evolutionary achievements of the differentiation-apoptosis programming [Rev. Neurosci. 12 (2001) 217]. Unicellular deprivation-induced differentiation into germ cell-like spores can be regarded as the archaic reproduction events which were fueled by the remains of the fratricided cells of the apoptotic fruiting body. Evidence has been accumulated suggesting that conserved through the ages as the evolutionary legacy of the germ-soma conflict, the somatic loss of immortality during the ontogenetic segregation of primordial germ cells recapitulates the archaic fate of the fruiting body. In this heritage, somatic death is a germ cell-triggered event and has been established as evolutionary-fixed default state following asymmetric reproduction in a world of finite resources. Aging, on the other hand, is the stress resistance-dependent phenotype of the somatic resilience that counteracts the germ cell-inflicted death pathway. Thus, aging is a survival response and, in contrast to current beliefs, is antagonistically linked to death that is not imposed by group selection but enforced upon the soma by the selfish genes of the "enemy within". Environmental conditions shape the trade-off solutions as compromise between the conflicting germ-soma interests. Mechanistically, the neuroendocrine system, particularly those components that control energy balance, reproduction and stress responses, orchestrate these events. The reproductive phase is a self-limited process that moulds onset and progress of senescence with germ cell-dependent factors, e.g. gonadal hormones. These degenerate the regulatory pacemakers of the pineal-hypothalamic-pituitary network and its peripheral, e.g. thymic, gonadal and adrenal targets thereby eroding the trophic milieu. The ensuing cellular metabolic stress engenders adaptive adjustments of the glucose-fatty acid cycle, responses that are adequate and thus fitness-boosting under fuel shortage (e.g. during caloric restriction) but become detrimental under fuel abundance. In a Janus-faced capacity, the cellular stress response apparatus expresses both tolerogenic and mutagenic features of the social and asocial deprivation responses [Rev. Neurosci. 12 (2001) 217]. Mediated by the derangement of the energy-Ca(2+)-redox homeostatic triangle, a mosaic of dedifferentiation/apoptosis and mutagenic responses actuates the gradual exhaustion of functional reserves and eventually results in a multitude of aging-related diseases. This scenario reconciles programmed and stochastic features of aging and resolves the major inconsistencies of current theories by linking ultimate and proximate causes of aging. Reproduction, differentiation, apoptosis, stress response and metabolism are merged into a coherent regulatory network that stages aging as a naturally selected, germ cell-triggered and reproductive phase-modulated deprivation response. PMID:12067599

Heininger, Kurt

2002-06-01

425

Vasa genes: Emerging roles in the germ line and in multipotent cells  

PubMed Central

Sexually reproducing metazoans establish a cell lineage during development that is ultimately dedicated to gamete production. Work in a variety of animals suggests that a group of conserved molecular determinants function in this germ line maintenance and function. The most universal of these genes are vasa and vasa-like DEAD box RNA helicase genes. However, recent evidence indicates that vasa genes also function in other cell types, distinct from the germ line. Here we evaluate our current understanding of vasa function and its regulation during development, addressing vasa’s emerging role in multipotent cells. We also explore the evolutionary diversification of the amino-terminal domain of this gene and how this impacts the association of vasa with nuage-like perinuclear structures. PMID:20586054

Gustafson, Eric A.; Wessel, Gary M.

2011-01-01

426

A suprasellar germ cell tumor in a 16-month-old Wagyu heifer calf  

PubMed Central

A 16-month-old Wagyu heifer calf presented for depression, inappetence, and polyuria/polydipsia. Physical examination revealed that the heifer calf was mentally dull, subjectively small for her age, bradycardic, and hypothermic and had bilateral nasal discharge. Laboratory tests revealed marked serum and cerebrospinal fluid hypernatremia and hyperchloremia with increased cerebrospinal fluid protein. The heifer calf was treated with Ringer solution intravenously for dehydration and electrolyte abnormalities, and with 1 dose each of thiamine and penicillin. Clinical deterioration prompted the owner to elect humane euthanasia. Necropsy revealed a mass lesion in the suprasellar region. Histopathology was consistent with a suprasellar germ cell tumor; the mass stained positive on immunohistochemistry for cytokeratin, vimentin, and c-kit. Suprasellar germ cell tumors have previously been reported in human beings and dogs. PMID:22529131

Brooks, Aimee N.; Brooks, Kelly N.; Oglesbee, Michael J.

2014-01-01

427

Primoridal germ cell specification: a context-dependent cellular differentiation event.  

PubMed

During embryonic development, the foundation of the germline is laid by the specification of primordial germ cells (PGCs) from the postimplantation epiblast via bone morphogenetic protein (BMP) and WNT signalling. While the majority of epiblast cells undergo differentiation towards somatic cell lineages, PGCs initiate a unique cellular programme driven by the cooperation of the transcription factors BLIMP1, PRDM14 and AP2?. These factors synergistically suppress the ongoing somatic differentiation and drive the re-expression of pluripotency and germ cell-specific genes accompanied by global epigenetic changes. However, an unresolved question is how postimplantation epiblast cells acquire the developmental competence for the PGC fate downstream of BMP/WNT signalling. One emerging concept is that transcriptional enhancers might play a central role in the establishment of developmental competence and the execution of cell fate determination. Here, we discuss recent advances on the specification and reprogramming of PGCs thereby highlighting the concept of enhancer function. PMID:25349452

Günesdogan, Ufuk; Magnúsdóttir, Erna; Surani, M Azim

2014-12-01

428

Primoridal germ cell specification: a context-dependent cellular differentiation event  

PubMed Central

During embryonic development, the foundation of the germline is laid by the specification of primordial germ cells (PGCs) from the postimplantation epiblast via bone morphogenetic protein (BMP) and WNT signalling. While the majority of epiblast cells undergo differentiation towards somatic cell lineages, PGCs initiate a unique cellular programme driven by the cooperation of the transcription factors BLIMP1, PRDM14 and AP2?. These factors synergistically suppress the ongoing somatic differentiation and drive the re-expression of pluripotency and germ cell-specific genes accompanied by global epigenetic changes. However, an unresolved question is how postimplantation epiblast cells acquire the developmental competence for the PGC fate downstream of BMP/WNT signalling. One emerging concept is that transcriptional enhancers might play a central role in the establishment of developmental competence and the execution of cell fate determination. Here, we discuss recent advances on the specification and reprogramming of PGCs thereby highlighting the concept of enhancer function. PMID:25349452

Günesdogan, Ufuk; Magnúsdóttir, Erna; Surani, M. Azim

2014-01-01

429

A non-surgical approach for male germ cell mediated gene transmission through transgenesis  

PubMed Central

Microinjection of foreign DNA in male pronucleus by in-vitro embryo manipulation is difficult but remains the method of choice for generating transgenic animals. Other procedures, including retroviral and embryonic stem cell mediated transgenesis are equally complicated and have limitations. Although our previously reported technique of testicular transgenesis circumvented several limitations, it involved many steps, including surgery and hemicastration, which carried risk of infection and impotency. We improved this technique further, into a two step non-surgical electroporation procedure, for making transgenic mice. In this approach, transgene was delivered inside both testes by injection and modified parameters of electroporation were used for in-vivo gene integration in germ cells. Using variety of constructs, germ cell integration of the gene and its transmission in progeny was confirmed by PCR, slot blot and immunohistochemical analysis. This improved technique is efficient, requires substantially less time and can be easily adopted by various biomedical researchers. PMID:24305437

Usmani, Abul; Ganguli, Nirmalya; Sarkar, Hironmoy; Dhup, Suveera; Batta, Suryaprakash R.; Vimal, Manoj; Ganguli, Nilanjana; Basu, Sayon; Nagarajan, P.; Majumdar, Subeer S.

2013-01-01

430

Engineering of a wheat germ expression system to provide compatibility with a high throughput pET-based cloning platform  

Microsoft Academic Search

Wheat germ cell-free methods provide an important approach for the production of eukaryotic proteins. We have developed a\\u000a protein expression vector for the TNT® SP6 High-Yield Wheat Germ Cell-Free (TNT WGCF) expression system (Promega) that is also compatible with our T7-based Escherichia coli intracellular expression vector pET15_NESG. This allows cloning of the same PCR product into either one of several

Li Zhao; Kate Q. Zhao; Robin Hurst; Michael R. Slater; Thomas B. Acton; G. V. T. Swapna; Ritu Shastry; Gregory J. Kornhaber; Gaetano T. Montelione

2010-01-01

431

Transgenerational Effects of Di-(2-ethylhexyl) Phthalate on Testicular Germ Cell Associations and Spermatogonial Stem Cells in Mice1  

PubMed Central

ABSTRACT Recent evidence has linked human phthalate exposure to abnormal reproductive and hormonal effects. Phthalates are plasticizers that confer flexibility and transparency to plastics, but they readily contaminate the body and the environment. In this study, timed pregnant CD1 outbred mice were treated with di-(2-ethylhexyl) phthalate (DEHP) from Embryonic Day 7 (E7) to E14. The subsequent generation (F1) offspring were then bred to produce the F2, F3, and F4 offspring, without any further DEHP treatment. This exposure scheme disrupted testicular germ cell association and decreased sperm count and motility in F1 to F4 offspring. By spermatogonial transplantation techniques, the exposure scheme also disrupted spermatogonial stem cell (SSC) function of F3 offspring. The W/WV recipient testes transplanted with F3 offspring germ cells from the DEHP-treated group had a dramatically lower percentage of donor germ cell-derived spermatogenic recovery in seminiferous tubules when compared to the recipient testes transplanted with CD1 control germ cells. Further characterization showed that the major block of donor germ cell-derived spermatogenesis was before the appearance of undifferentiated spermatogonia. Interestingly, the testes transplanted with the F3 offspring germ cells from the DEHP-treated group, when regenerated, replicated testis morphology similar to that observed in the testes from the F1 to F3 offspring of the DEHP-treated group, suggesting that the germ cell disorganization phenotype originates from the stem cells of F3 offspring. In conclusion, embryonic exposure to DEHP was found to disrupt testicular germ cell organization and SSC function in a transgenerational manner. PMID:23536373

Doyle, Timothy J.; Bowman, Jennifer L.; Windell, Veronica L.; McLean, Derek J.; Kim, Kwan Hee

2013-01-01

432

Differential Expression of Conserved Germ Line Markers and Delayed Segregation of Male and Female Primordial Germ Cells in a Hermaphrodite, the Leech Helobdella  

PubMed Central

In sexually reproducing animals, primordial germ cells (PGCs) are often set aside early in embryogenesis, a strategy that minimizes the risk of genomic damage associated with replication and mitosis during the cell cycle. Here, we have used germ line markers (piwi, vasa, and nanos) and microinjected cell lineage tracers to show that PGC specification in the leech genus Helobdella follows a different scenario: in this hermaphrodite, the male and female PGCs segregate from somatic lineages only after more than 20 rounds of zygotic mitosis; the male and female PGCs share the same (mesodermal) cell lineage for 19 rounds of zygotic mitosis. Moreover, while all three markers are expressed in both male and female reproductive tissues of the adult, they are expressed differentially between the male and female PGCs of the developing embryo: piwi and vasa are expressed preferentially in female PGCs at a time when nanos is expressed preferentially in male PGCs. A priori, the delayed segregation of male and female PGCs from somatic tissues and from one another increases the probability of mutations affecting both male and female PGCs of a given individual. We speculate th