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Somatic Cells (somatic + cell)
Terms modified by Somatic Cells Selected AbstractsGlutathione and adenosine triphosphate content of in vivo and in vitro matured porcine oocytesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003A.M. Brad Abstract Glutathione (GSH) content in mature porcine oocytes is correlated with subsequent fertilization and developmental success. Adenosine triphosphate (ATP) is an important energy source for maintaining cellular activities and protein synthesis. The objective of this study was to compare GSH and ATP concentrations of in vivo and in vitro matured porcine oocytes. Ovulated, in vivo matured oocytes were frozen at ,80°C in groups of 10,20 (GSH) or 5,10 (ATP). In vitro oocytes were matured in either tissue culture medium-199 (TCM199) supplemented with polyvinyl alcohol (PVA) or hyaluronic acid (MAP5), or North Carolina State University-23 (NCSU23) supplemented with porcine follicular fluid (pFF) and frozen as described, or fertilized and cultured. GSH content was determined by the dithionitrobenzoic acid,glutathione disulfide (DTNB,GSSG) reductase recycling assay. ATP content was determined by using the Bioluminescent Somatic Cell Assay Kit. Oocytes matured in vitro in defined TCM199 with PVA or hyaluronic acid, or NCSU23 with pFF had significantly lower concentrations (P,<,0.05) of GSH (n,=,207, 9.82,±,0.71 pmol/oocyte; n,=,104, 9.73,±, 0.81 pmol/oocyte; n,=,108, 7.89,±,0.66 pmol/oocyte, respectively) compared to in vivo matured oocytes (n,=,217, 36.26,±,11.00 pmol/oocyte). Concentrations of ATP were not different between treatments (in vivo, n,=,70, 0.97,±,0.07 pmol/oocyte; TCM,PVA, n,=,117, 0.81,±,0.13 pmol/oocyte; TCM,MAP, n,=,107, 1.02,±,0.18 pmol/oocyte; NCSU,pFF, n,=,134, 0.71,±,0.08 pmol/oocyte). Intracellular ATP content does not appear to be related to developmental potential in porcine oocytes. Low intracellular GSH may be responsible, in part, for lower developmental competence observed in in vitro matured porcine oocytes. Mol. Reprod. Dev. 64: 492,498, 2003. © 2003 Wiley-Liss, Inc. [source] Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea PigsREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2010LR Maschio Contents In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ-cell morphology remain unclear. This study evaluates the short-term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30-day old) and adult (65- and 135-day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non-steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post-pubertal and adult guinea pigs, in addition to causing germ-cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis. [source] Co-culture of Buffalo Preantral Follicles with Different Somatic CellsREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2008HS Ramesh Contents The effect of co-culture of buffalo preantral follicles (PFs) with different somatic cells, i.e, cumulus, granulosa, ovarian mesenchymal and oviductal epithelial cells was studied. Large PFs (250,450 ,m) were isolated by microdissecting the trypsin (1%) digested ovarian cortical slices. Cumulus cells were isolated by repeated pipetting of oocytes, granulosa cells were isolated by aspirating from punctured PFs and ovarian mesenchymal cells were isolated from ovarian cortex by scraping the cortical slices and passing through 20 ,m filter. Preantral follicles were cultured in standard culture medium without somatic cells or co-cultured with cumulus cells, granulosa cells, ovarian mesenchymal cells and oviductal epithelial cells for 80 days. The growth rate (,m/day) of the PFs was monitored by measuring follicular diameter on day 0, 30, 60 and 80 days of culture. The viability of PFs was evaluated by trypan blue staining. The results indicated that PFs co-cultured with cumulus, granulosa and ovarian mesenchymal cells had a better development and survivality compared with control and those co-culture with oviductal epithelial cells. Maximum growth and survivality of PFs were achieved when cultured with cumulus cells. It is concluded that inclusion of somatic cells in PF culture media had beneficial effect on the growth of PFs and cumulus cells supported maximum growth and survivality of PFs in vitro of all somatic cells tested. [source] ALTERNATE NUCLEAR TRANSFER IS NO ALTERNATIVE FOR EMBRYONIC STEM CELL RESEARCHBIOETHICS, Issue 2 2008JOHN A. FENNEL ABSTRACT Recent developments allow for the creation of human stem cells without the creation of human embryos, a process called alternate nuclear transfer (,ANT'). Pursuing this method of stem cell research makes sense for pro-lifers if arguments for the sanctity of the human embryo do not apply to ANT. However, the technology that makes ANT possible undermines the erstwhile technical barrier between human embryos and somatic cell DNA. These advances bring home the force of hypothetical arguments about the potential of the DNA in somatic cells, showing that there is not a morally relevant difference between the potential of an embryo and the potential of the DNA in a somatic cell. Therefore, the supposed distinction between entities that are potential human life and entities that are human life does not give any support to arguments for the sanctity of the human embryo because those arguments extend value to too many entities. [source] Cellular and molecular dissection of pluripotent adult somatic stem cells in planariansDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2010Norito Shibata Freshwater planarians, Plathelminthes, have been an intriguing model animal of regeneration studies for more than 100 years. Their robust regenerative ability is one of asexual reproductive capacity, in which complete animals develop from tiny body fragments within a week. Pluripotent adult somatic stem cells, called neoblasts, assure this regenerative ability. Neoblasts give rise to not only all types of somatic cells, but also germline cells. During the last decade, several experimental techniques for the analysis of planarian neoblasts at the molecular level, such as in situ hybridization, RNAi and fluorescence activated cell sorting, have been established. Moreover, information about genes involved in maintenance and differentiation of neoblasts has been accumulated. One of the molecular features of neoblasts is the expression of many RNA regulators, which are involved in germline development in other animals, such as vasa and piwi family genes. In this review, we introduce physiological and molecular features of the neoblast, and discuss how germline genes regulate planarian neoblasts and what differences exist between neoblasts and germline cells. [source] Spatio-temporal expression of Xenopus vasa homolog, XVLG1, in oocytes and embryos: The presence of XVLG1 RNA in somatic cells as well as germline cellsDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2000Kohji Ikenishi The expression of Xenopus vasa homolog or XVLG1 was examined in oocytes and embryos by whole-mount in situ hybridization and reverse transcription,polymerase chain reaction (RT-PCR). To confirm the results in embryos, both methods were also applied to explants of germ plasm-bearing cells (GPBC) from 32-cell embryos and to those of partial embryos deprived of GPBC. By hybridization, XVLG1 ribonucleic acid (RNA) was shown to be present throughout the cytoplasm in oocytes at stages I,III, except for the mitochondrial cloud. It was barely recognizable in a portion of germline cells of embryos at specific stages, notwithstanding that XVLG1 protein was present in those cells almost throughout their life-span. A weak signal for the RNA was detectable in some of the presumptive primordial germ cells (pPGC, descendants of GPBC from the gastrula stage onward) from the late gastrula (stage 12) to the hatching tadpole stage (stage 33/34), and in some of the PGC at stages 49,50. The results for pPGC were confirmed by the hybridization of explants of GPBC at equivalent stages in control embryos. In contrast, XVLG1 RNA was detected in certain somatic cells of embryos until stage 46. These observations were supported in part by the results of RT-PCR for embryos and explants. The possible role of the product of XVLG1 was reconsidered given its presence in both germline and somatic cells. [source] Sdmg1 is a component of secretory granules in mouse secretory exocrine tissuesDEVELOPMENTAL DYNAMICS, Issue 1 2009Diana Best Abstract Sdmg1 is a conserved eukaryotic transmembrane protein that is mainly expressed in the gonads where it may have a role in mediating signaling between somatic cells and germ cells. In this study we demonstrate that secretory exocrine cells in the pancreas, salivary gland, and mammary gland also express Sdmg1. Furthermore, we show that Sdmg1 expression is up-regulated during pancreas development when regulated secretory granules start to appear, and that Sdmg1 colocalizes with secretory granule markers in adult pancreatic acinar cells. In addition, we show that Sdmg1 co-purifies with secretory granules during subcellular fractionation of the pancreas and that Sdmg1 and the secretory granule marker Vamp2 are localized to distinct subdomains in the secretory granule membrane. These data suggest that Sdmg1 is a component of regulated secretory granules in exocrine secretory cells and that the developmental regulation of Sdmg1 expression is related to a role for Sdmg1 in post-Golgi membrane trafficking. Developmental Dynamics 238:223,231, 2009. © 2008 Wiley-Liss, Inc. [source] Stretching the limits: Stem cells in regeneration scienceDEVELOPMENTAL DYNAMICS, Issue 12 2008David L. Stocum Abstract The focus of regenerative medicine is rebuilding damaged tissues by cell transplantation or implantation of bioartificial tissues. In either case, therapies focus on adult stem cells (ASCs) and embryonic stem cells (ESCs) as cell sources. Here we review four topics based on these two cell sources. The first compares the current performance of ASCs and ESCs as cell transplant therapies and the drawbacks of each. The second explores somatic cell nuclear transfer (SCNT) as a method to derive ESCs that will not be immunorejected. The third topic explores how SCNT and ESC research has led to the ability to derive pluripotent ESCs by the dedifferentiation of adult somatic cells. Lastly, we discuss how research on activation of intrinsic adult stem cells and on somatic cell dedifferentiation can evolve regenerative medicine from a platform consisting of cell transplantation to one that includes the chemical induction of regeneration from the body's own cells at the site of injury. Developmental Dynamics 237:3648,3671, 2008. © 2008 Wiley-Liss, Inc. [source] A challenge for regenerative medicine: Proper genetic programming, not cellular mimicryDEVELOPMENTAL DYNAMICS, Issue 12 2007Angie Rizzino Abstract Recent progress in stem cell biology and the reprogramming of somatic cells to a pluripotent phenotype has generated a new wave of excitement in regenerative medicine. Nonetheless, efforts aimed at understanding transdifferentiation, dedifferentiation, and the plasticity of cells, as well as the ability of somatic cells to be reprogrammed, has raised as many questions as those that have been answered. This review proffers the argument that many reports of transdifferentiation, dedifferentiation, and unexpected stem cell plasticity may be due to aberrant processes that lead to cellular look-alikes (cellular mimicry). In most cases, cellular look-alikes can now be identified readily by monitoring gene expression profiles, as well as epigenetic modifications of DNA and histone proteins of the cells involved. This review further argues that progress in regenerative medicine will be significantly hampered by failing to address the issue of cellular look-alikes. Developmental Dynamics 236:3199,3207, 2007. © 2007 Wiley-Liss, Inc. [source] GATA-4 is required for sex steroidogenic cell development in the fetal mouseDEVELOPMENTAL DYNAMICS, Issue 1 2007Malgorzata Bielinska Abstract The transcription factor GATA-4 is expressed in Sertoli cells, steroidogenic Leydig cells, and other testicular somatic cells. Previous studies have established that interaction between GATA-4 and its cofactor FOG-2 is necessary for proper Sry expression and all subsequent steps in testicular organogenesis, including testis cord formation and differentiation of both Sertoli and fetal Leydig cells. Since fetal Leydig cell differentiation depends on Sertoli cell,derived factors, it has remained unclear whether GATA-4 has a cell autonomous role in Leydig cell development. We used two experimental systems to explore the role of GATA-4 in the ontogeny of testicular steroidogenic cells. First, chimeric mice were generated by injection of Gata4,/, ES cells into Rosa26 blastocysts. Analysis of the resultant chimeras showed that in developing testis Gata4,/, cells can contribute to fetal germ cells and interstitial fibroblasts but not fetal Leydig cells. Second, wild-type or Gata4,/, ES cells were injected into the flanks of intact or gonadectomized nude mice and the resultant teratomas examined for expression of steroidogenic markers. Wild-type but not Gata4,/, ES cells were capable of differentiating into gonadal-type steroidogenic lineages in teratomas grown in gonadectomized mice. In chimeric teratomas derived from mixtures of GFP-tagged Gata4+/+ ES cells and unlabeled Gata4,/, ES cells, sex steroidogenic cell differentiation was restricted to GFP-expressing cells. Collectively these data suggest that GATA-4 plays an integral role in the development of testicular steroidogenic cells. Developmental Dynamics 236:203,213, 2007. © 2006 Wiley-Liss, Inc. [source] Two DM domain genes, DMY and DMRT1, involved in testicular differentiation and development in the medaka, Oryzias latipesDEVELOPMENTAL DYNAMICS, Issue 3 2004Tohru Kobayashi Abstract The recent discovery of the DMY gene (DM domain gene on Y chromosome and one of the DMRT1 family genes) as a key determinant of male development in the medaka (Oryzias latipes) has led to its designation as the prime candidate gene for sex-determination in this species. This study focused on the sites and pattern of expression of DMY and DMRT1 genes during gonadal differentiation of medaka to further determine their roles in testis development. DMY mRNA and protein are expressed specifically in the somatic cells surrounding primordial germ cells (PGCs) in the early gonadal primordium, before morphological sex differences are seen. However, somatic cells surrounding PGCs never express DMY during the early migratory period. Expression of DMY persists in Sertoli cell lineage cells, from PGC-supporting cells to Sertoli cells, indicating that only DMY -positive cells enclose PGCs during mitotic arrest after hatching. DMRT1 is expressed in spermatogonium-supporting cells after testicular differentiation (20,30 days after hatching), and its expression is much higher than that of DMY in mature testes. In XX sex-reversed testes, DMRT1 is expressed in the Sertoli cell lineage, similar to the expression of DMY in XY testes. These results suggest strongly that DMY regulates PGC proliferation and differentiation sex-specifically during early gonadal differentiation of XY individuals and that DMRT1 regulates spermatogonial differentiation. Developmental Dynamics 231:518,526, 2004. © 2004 Wiley-Liss, Inc. [source] DNA damage in leukocytes of workers occupationally exposed to arsenic in copper smeltersENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2005Jadwiga Palus Abstract Inorganic arsenic (i-As) is a known human carcinogen; however, humans continue to be exposed to i-As in drinking water and in certain occupational settings. In this study, we used the Comet assay to evaluate DNA damage in the somatic cells of workers from three Polish copper smelters who were occupationally exposed to i-As. Blood samples were collected from 72 male workers and 83 unexposed male controls and used for the detection of DNA damage, oxidative DNA damage, and DNA damage after a 3-hr incubation in culture. Urine samples were collected to assess the level of exposure. The mean concentration of arsenic metabolites in urine [the sum of arsenite (AsIII), arsenate (AsV), monomethylarsenate (MMA) and dimethylarsenate (DMA)] and the concentrations of DMA (the main metabolite in urine) were higher in workers than in controls, but the differences were not statistically significant. By contrast, the level of DNA damage, expressed as the median tail moment, was significantly higher in the leukocytes of workers than in the controls. Comet assays conducted with formamidopyrimidine glycosylase (FPG) digestion to detect oxidative DNA damage indicated that oxidative lesions were present in leukocytes from both the exposed and control groups, but the levels of damage were significantly higher among the workers. Incubation of the cells in culture resulted in a significant reduction in the levels of DNA damage, especially among leukocytes from the workers, suggesting that the DNA damage was subject to repair. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. Although i-As was present in air samples from the smelters and in urine samples from workers, no clear association could be made between i-As exposure and the DNA damage. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source] Expression of individual immunoglobulin genes occurs in an unusual system consisting of multiple independent lociEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2004Donna Abstract Humoral immunity is effected through the rearrangement of immunoglobulin (Ig) genes in individual somatic cells committed to the B,lymphocyte lineage. Haplotype or allelic exclusion restricts B,lymphocytes to the expression of a single Ig receptor that can sustain further somatic modification. In most species, a specific Ig chain is encoded at a single genetic locus. However, in cartilaginous fish, hundreds of independent Ig heavy- (IgH) and Ig light-chain (IgL) gene loci are present, many of which are joined in the germ line. Ig gene transcripts have been amplified from single peripheral blood lymphocytes isolated from the clearnose skate (Raja eglanteria) using reverse-transcription PCR, and a single productive IgH transcript was detected in the majority of cells analyzed. Similarly, only a single IgL transcript was detected in over half of the individual cells. Taken together, these findings suggest that a mechanism for haplotype exclusion arose early in the evolution of antibody diversity and is independent of a single genetic locus. [source] ON THE EVOLUTION OF DIFFERENTIATED MULTICELLULARITYEVOLUTION, Issue 2 2009Martin Willensdorfer Most conspicuous organisms are multicellular and most multicellular organisms develop somatic cells to perform specific, nonreproductive tasks. The ubiquity of this division of labor suggests that it is highly advantageous. In this article I present a model to study the evolution of specialized cells. The model allows for unicellular and multicellular organisms that may contain somatic (terminally differentiated) cells. Cells contribute additively to a quantitative trait. The fitness of the organism depends on this quantitative trait (via a benefit function), the size of the organism, and the number of somatic cells. The model allows one to determine when somatic cells are advantageous and to calculate the optimum number (or fraction) of reproductive cells. I show that the fraction of reproductive cells is always surprisingly high. If somatic cells are very small, they can outnumber reproductive cells but their biomass is still less than the biomass of reproductive cells. I discuss the biology of primitive multicellular organisms with respect to the model predictions. I find a good agreement and outline how this work can be used to guide further quantitative studies of multicellularity. [source] SEXUAL ANTAGONISM AND THE EVOLUTION OF X CHROMOSOME INACTIVATIONEVOLUTION, Issue 8 2008Jan Engelstädter In most female mammals, one of the two X chromosomes is inactivated early in embryogenesis. Expression of most genes on this chromosome is shut down, and the inactive state is maintained throughout life in all somatic cells. It is generally believed that X-inactivation evolved as a means of achieving equal gene expression in males and females (dosage compensation). Following degeneration of genes on the Y chromosome, gene expression on X chromosomes in males and females is upregulated. This results in closer to optimal gene expression in males, but deleterious overexpression in females. In response, selection is proposed to favor inactivation of one of the X chromosomes in females, restoring optimal gene expression. Here, we make a first attempt at shedding light on this intricate process from a population genetic perspective, elucidating the sexually antagonistic selective forces involved. We derive conditions for the process to work and analyze evolutionary stability of the system. The implications of our results are discussed in the light of empirical findings and a recently proposed alternative hypothesis for the evolution of X-inactivation. [source] Gene Transfer Strategies for the PhysiologistEXPERIMENTAL PHYSIOLOGY, Issue 6 2000Liang-Fong Wong Foreign genes can be introduced into whole animals using methods of germline transgenesis and somatic gene delivery. While germline transgenesis can generate useful animal models for genetic studies, it can be costly, time-consuming and requires the use of a large number of animals. An alternative means of gene transfer is to deliver genes to somatic cells using non-viral and viral technologies. Non-viral methods such as naked DNA injection, electroporation and liposome/cation lipid-mediated gene transfer are relatively inefficient. In contrast, viruses are effective vehicles that carry foreign genes into a cell rapidly and efficiently. Here we illustrate the usefulness of adenoviral vectors to express a potent and specific inhibitor of cAMP-dependent protein kinase (PKA) to study the role of cyclic 3,,5,-cyclic AMP (cAMP) in the osmotic regulation of the vasopressin gene in a transgenic rat model. The ability to modify endogenous systems within specific cells in a whole animal model allows gene effects to be studied with physiological relevance. The combination of molecular biology and integrative physiology is a powerful application that can aid in the elucidation of how gene function can translate into complex systems in an organism [source] Alu-DNA repeat-binding protein p68 is a part of Alu-RNA containing ,-RNPFEBS JOURNAL, Issue 8 2000Dmitry V. Lukyanov An Alu-DNA repeat-binding protein with a molecular mass of 68 kDa (p68) is identified in the somatic human cell nucleoplasm. Gel mobility shift assay (GMSA), South-western blotting and affinity purification on DNA attached to the carrier were used in the identification. GMSA revealed multiple complexes with the exponential dependence of their relative mobility. A narrow binding site of the p68 was revealed using synthetic oligonucleotides. It is located between the A-box and B-box of the RNA polymerase III promoter and is identical to that reported for the Alu-binding protein from human spermatozoids. The same narrow binding site, the similarity of the isolation procedure from germ and somatic cells, and similar binding properties and molecular masses suggest homology of the two proteins. Antibodies raised against Alu-protein complexes led to hypershift of the complexes in GMSA and stained p68 in active fractions in human spermatozoids and in Alu-RNA-containing ,-RNP particles. Immunofluorescence of a HeLa cell monolayer revealed an intranuclear dot pattern with the dots corresponding to euchromatin areas and some dots located at the cell periphery in the cytoplasm. ,-RNP particles bound Alu-DNA in vitro and contained p68 as shown using the immunogold procedure. Alu-DNA binding activity was revealed in cytoplasm as well as in nucleoplasm. The possible nature of the main Alu-DNA binding protein and its involvement in the particle structure are discussed. [source] TCL1 is activated by chromosomal rearrangement or by hypomethylationGENES, CHROMOSOMES AND CANCER, Issue 4 2001Martin R. Yuille TCL1 is an oncogene activated by recurrent reciprocal translocations at chromosome segment 14q32.1 in the most common of the mature T-cell malignancies, T-cell prolymphocytic leukemia. It acts to transport Akt1 to the nucleus and enhance Akt1's serine-threonine kinase activity. TCL1 is also expressed in the B-cell malignancy, Burkitt's lymphoma (BL). However, 14q32.1 breakpoints have not been detected in BL, and we therefore investigated in more detail how expression was activated. No evidence for rearrangement near TCL1 was found in BL. Instead, a NotI site adjacent to the TATA box in the TCL1 promoter was found to be unmethylated. By contrast, tumor cell lines not expressing TCL1 were fully methylated at this NotI site, while normal somatic cells were hemimethylated. We also found that TCL1 was expressed in B-cell chronic lymphocytic leukemia (CLL) and the related disorder splenic lymphoma with villous lymphocytes (unlike in normal mature B-cells), and that the NotI site was unmethylated on both alleles. This correlation of repression and methylation was tested in vitro. When cells with both alleles methylated at the NotI site were demethylated, TCL1 expression was induced. These data provide evidence that in mature B-cell malignancies there is an alternative mechanism of TCL1 activation that apparently involves loss of methylation of one promoter allele. We discuss the significance of this for CLL tumorigenesis and for genomewide hypomethylation in CLL. © 2001 Wiley-Liss, Inc. [source] slowmo is required for Drosophila germline proliferationGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 2 2007Simon Reeve Abstract Null mutations in the Drosophila gene, slowmo (slmo), result in reduced mobility and lethality in first-instar larvae. Slowmo encodes a mitochondrial protein of unknown function, as do the two other homologs found in Drosophila. Here, we have studied a hypomorphic P-element allele of slmo demonstrating its effects on germline divisions in both testes and ovaries. Using in situ studies, enhancer-trap activity, and promoter fusions, we have shown that slmo expression in testes is found in the somatic cyst cells (SCC). The hypomorphic allele for Slmo revealed apoptotic loss of germline cells in the larval germline, culminating in a complete absence of the germline in adult flies. In females, a similar degeneration of the germarium is observed, while reporter gene expression is found in both germline and somatic cells. Using a null mutation in female germline clones, we find slmo is dispensable from the germline cells. Our results suggest that Slowmo is not required in germline cells directly, but is required in SCCs responsible for maintaining germline survival in both sexes. genesis 45:66,75, 2007. © 2007 Wiley-Liss, Inc. [source] The reprogramming factors of human somatic cells are novel targets for human hepatocellular carcinoma therapy,HEPATOLOGY, Issue 6 2009Hisashi Moriguchi M.P.H., Ph.D. No abstract is available for this article. [source] The A-type cyclins and the meiotic cell cycle in mammalian male germ cellsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2004Debra J. Wolgemuth Summary There are two mammalian A-type cyclins, cyclin Al and A2. While cyclin A1 is limited to male germ cells, cyclin A2 is widely expressed. Cyclin A2 promotes both Gl/S and G2/M transitions in somatic cells and cyclin A2-deficient mice are early embryonic lethal. We have shown that cyclin Al is essential for passage of spermatocytes into meiosis I (MI) by generating mice null for the cyclin A1 gene Ccna1. Both Ccna1,/, males and females were healthy but the males were sterile because of a cell cycle arrest before MI. This arrest was associated with desynapsis abnormalities, low M-phase promoting factor activity, and apoptosis. We have now determined that human cyclin A1 is expressed in similar stages of spermatogenesis and are exploring its role in human male infertility and whether it may be a novel target for new approaches for male contraception. [source] Effects of somatic cell counts on the physicochemical and rheological properties of yoghurt made from sheep's milkINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2010Masoud Najaf Najafi Summary In the present work, yoghurts were made from sheep's milk with two different somatic cell count (SCC), at low (200 000 cells mL,1) and high (750 000 cells mL,1) levels. The characteristics of the final product were analysed for pH, acidity, protein, total solids, fat, syneresis, water holding capacity (WHC) and apparent viscosity. Samples were analysed on days 1, 7 and 14 after production of yoghurts. The SCC had no significant effect either on the acidity or pH of the yoghurt at 24 h (P > 0.05) but a significant effect (P < 0.05) was observed at 168 h. No effects of SCC were observed on total solids and fat content of the yoghurt after 24 and 168 h. High SCC (HSCC) yoghurt had higher protein content (P < 0.05). The yoghurt with the highest SCC had the highest level of syneresis. Viscosity of HSCC yoghurt was higher than that of the low SCC yoghurt on days 1, 7 and 14 of storage. The flow properties also showed that the low SCC yoghurt was softer than that from milk with high content in somatic cells. [source] Is iPS cell the panacea?IUBMB LIFE, Issue 3 2010Li Ou Abstract In 2006, it was reported that transgenic expression of merely four defined transcription factors (c-Myc, Klf4, Oct4, and Sox2) is sufficient to reprogram somatic cells to a pluripotent state. The resulting induced pluripotent stem (iPS) cells ignited intense interest in the field of life science for their promising applications in basic biology, drug development, and transplantation. However, the underlying problems of iPS cells seem to be ignored. This review shed light on the problems pertaining iPS cells, including the elusive origin, risk of tumorgenesis, and its relationship with natural selection. © 2010 IUBMB IUBMB Life, 62(3): 170,175, 2010 [source] Ploidy manipulation using diploid sperm in the loach, Misgurnus anguillicaudatus: a reviewJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2008H. Yoshikawa Summary This paper assesses the present state of the art of ploidy manipulation in the loach, Misgurnus anguillicaudatus (Teleoste: Cobitidae). Diploid sperm can be obtained from natural tetraploid individuals with four sets of homologous chromosomes. Using diploid sperm, various polyploids and androgenetic diploids have been produced. Cryptic clonal lineages are also recognized in wild populations of the loach. They produce unreduced diploid eggs genetically identical to somatic cells of the mother fish and most diploid eggs develop gynogenetically as a member of the clone. However, some eggs develop to triploid and/or diploid-triploid mosaic individuals by incorporation of sperm nucleus. Diploid-triploid mosaic males exclusively generate fertile diploid sperm with clonal genotypes. Such diploid sperm can also be obtained from artificially sex-reversed clonal individuals. Recent population studies suggested that Japanese M. anguillicaudatus might not be a single species, but a complex involving cryptic species, because wild populations exhibited genetic differentiation at interspecific level. This implies possible relationship between atypical reproduction and natural hybridization in the loach. [source] The telomere length dynamic and methods of its assessmentJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2005Kah-Wai Lin Abstract Human telomeres are composed of long repeating sequences of TTAGGG, associated with a variety of telomere-binding proteins. Its function as an end-protector of chromosomes prevents the chromosome from end-to-end fusion, recombination and degradation. Telomerase acts as reverse transcriptase in the elongation of telomeres, which prevent the loss of telomeres due to the end replication problems. However, telomerase activity is detected at low level in somatic cells and high level in embryonic stem cells and tumor cells. It confers immortality to embryonic stem cells and tumor cells. In most tumor cells, telomeres are extremely short and stable. Telomere length is an important indicator of the telomerase activity in tumor cells and it may be used in the prognosis of malignancy. Thus, the assessment of telomeres length is of great experimental and clinical significance. This review describes the role of telomere and telomerase in cancer pathogenesis and the dynamics of the telomeres length in different cell types. The various methods of measurement of telomeres length, i.e. southern blot, hybridization protection assay, fluorescence in situ hybridization, primed in situ, quantitative PCR and single telomere length analysis are discussed. The principle and comparative evaluation of these methods are reviewed. The detection of G-strand overhang by telomeric-oligonucleotide ligation assay, primer extension/nick translation assay and electron microscopy are briefly discussed. [source] Retroviral vector silencing during iPS cell induction: An epigenetic beacon that signals distinct pluripotent statesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2008Akitsu Hotta Abstract Retroviral vectors are transcriptionally silent in pluripotent stem cells. This feature has been potently applied in studies that reprogram somatic cells into induced pluripotent stem (iPS) cells. By delivering the four Yamanaka factors in retroviral vectors, high expression is obtained in fibroblasts to induce the pluripotent state. Partial reprogramming generates Class I iPS cells that express the viral transgenes and endogenous pluripotency genes. Full-reprogramming in Class II iPS cells silences the vectors as the endogenous genes maintain the pluripotent state. Thus, retroviral vector silencing serves as a beacon marking the fully reprogrammed pluripotent state. Here we review known silencer elements, and the histone modifying and DNA methylation pathways, that silence retroviral and lentiviral vectors in pluripotent stem cells. Both retroviral and lentiviral vectors are influenced by position effects and often exhibit variegated expression. The best vector designs facilitate full-reprogramming and subsequent retroviral silencing, which is required for directed-differentiation. Current retroviral reprogramming methods can be immediately applied to create patient-specific iPS cell models of human disease, however, future clinical applications will require novel chemical or other reprogramming methods that reduce or eliminate the integrated vector copy number load. Nevertheless, retroviral vectors will continue to play an important role in genetically correcting patient iPS cell models. We anticipate that novel pluripotent-specific reporter vectors will select for isolation of high quality human iPS cell lines, and select against undifferentiated pluripotent cells during regenerative medicine to prevent teratoma formation after transplantation. J. Cell. Biochem. 105: 940,948, 2008. © 2008 Wiley-Liss, Inc. [source] The sperm nuclear matrix is required for paternal DNA replication,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2007Jeffrey A. Shaman Abstract The mammalian sperm nucleus provides an excellent model for studying the relationship between the formation of nuclear structure and the initiation of DNA replication. We previously demonstrated that mammalian sperm nuclei contain a nuclear matrix that organizes the DNA into loop domains in a manner similar to that of somatic cells. In this study, we tested the minimal components of the sperm nucleus that are necessary for the formation of the male pronucleus and for the initiation of DNA synthesis. We extracted mouse sperm nuclei with high salt and dithiothreitol to remove the protamines in order to form nuclear halos. These were then treated with either restriction endonucleases to release the DNA not directly associated with the nuclear matrix or with DNAse I to digest all the DNA. The treated sperm nuclei were injected into oocytes, and the paternal pronuclear formation and DNA synthesis was monitored. We found that restriction digested sperm nuclear halos were capable of forming paternal pronuclei and initiating DNA synthesis. However, when isolated mouse sperm DNA or sperm DNA reconstituted with the nuclear matrices were injected into oocytes, no paternal pronuclear formation or DNA synthesis was observed. These data suggest that the in situ nuclear matrix attachment organization of sperm DNA is required for mouse paternal pronuclear DNA synthesis. J. Cell. Biochem. 102: 680,688, 2007. © 2007 Wiley-Liss, Inc. [source] Telomere uncapping during in vitro T-lymphocyte senescenceAGING CELL, Issue 1 2009Amel Chebel Summary Normal lymphocytes represent examples of somatic cells that are able to induce telomerase activity when stimulated. As previously reported, we showed that, during lymphocyte long-term culture and repeated stimulations, the appearance of senescent cells is associated with telomere shortening and a progressive drop in telomerase activity. We further showed that this shortening preferentially occured at long telomeres and was interrupted at each stimulation by a transitory increase in telomere length. In agreement with the fact that telomere uncapping triggers lymphocyte senescence, we observed an increase in ,-H2AX and 53BP1 foci as well as in the percentage of cells exhibiting DNA damage foci in telomeres. Such a DNA damage response may be related to the continuous increase of p16ink4a upon cell stimulation and cell aging. Remarkably, at each stimulation, the expression of shelterin genes, such as hTRF1, hTANK1, hTIN2, hPOT1 and hRAP1, was decreased. We propose that telomere dysfunction during lymphocyte senescence caused by iterative stimulations does not only result from an excessive telomere shortening, but also from a decrease in shelterin content. These observations may be relevant for T-cell biology and aging. [source] Senescence-associated ,-galactosidase is lysosomal ,-galactosidaseAGING CELL, Issue 2 2006Bo Yun Lee Summary Replicative senescence limits the proliferation of somatic cells passaged in culture and may reflect cellular aging in vivo. The most widely used biomarker for senescent and aging cells is senescence-associated ,-galactosidase (SA-,-gal), which is defined as ,-galactosidase activity detectable at pH 6.0 in senescent cells, but the origin of SA-,-gal and its cellular roles in senescence are not known. We demonstrate here that SA-,-gal activity is expressed from GLB1, the gene encoding lysosomal ,-D-galactosidase, the activity of which is typically measured at acidic pH 4.5. Fibroblasts from patients with autosomal recessive GM1 -gangliosidosis, which have defective lysosomal ,-galactosidase, did not express SA-,-gal at late passages even though they underwent replicative senescence. In addition, late passage normal fibroblasts expressing small-hairpin interfering RNA that depleted GLB1 mRNA underwent senescence but failed to express SA-,-gal. GLB1 mRNA depletion also prevented expression of SA-,-gal activity in HeLa cervical carcinoma cells induced to enter a senescent state by repression of their endogenous human papillomavirus E7 oncogene. SA-,-gal induction during senescence was due at least in part to increased expression of the lysosomal ,-galactosidase protein. These results also indicate that SA-,-gal is not required for senescence. [source] Developmental morphology of the neonatal alligator (Alligator mississippiensis) ovaryJOURNAL OF MORPHOLOGY, Issue 3 2008Brandon C. Moore Abstract American alligator (Alligator mississippiensis) ovary development is incomplete at hatching. During the months following hatching, the cortical processes of oogenesis started in ovo continues and folliculogenesis is initiated. Additionally, the medullary region of the gonad undergoes dramatic restructuring. We describe alligator ovarian histology at hatching, 1 week, 1 month, and 3 months of age in order to characterize the timing of morphological development and compare these findings to chicken ovary development. At hatching, the ovarian cortex presents a germinal epithelium containing oogonia and a few primary oocytes irregularly scattered between somatic epithelial cells. The hatchling medulla shows fragmentation indicative of the formation of lacunae. By 1 week of age, oocytes form growing nests and show increased interactions with somatic cells, indicative of the initiation of folliculogenesis. Medullary lacunae increase in diameter and contain secretory material in their lumen. At 1 month, nest sizes and lacunar diameters continue to enlarge. Pachytene oocytes surrounded by somatic cells are more frequent. Trabeculae composed of dense irregular connective tissue divide cortical nests. Three months after hatching oocytes in meiotic stages of prophase I up to diplotene are present. The ovary displays many enlarged follicles with oocytes in diplotene arrest, thecal layers, lampbrush chromosomes, and complete layers of follicular cells. The medulla is an elaborated complex of vascularized lacunae underlying the cortex and often containing discrete lymphoid aggregates. While the general morphology of the alligator ovary is similar to that of the chicken ovary, the progression of oogenesis and folliculogenesis around hatching is notably slower in alligators. Diplotene oocytes are observed at hatching in chickens, but not until 3 months in alligators. Folliculogenesis is completed at 3 weeks in chickens whereas it is still progressing at 3 months in alligators. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||