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Sample records for induces ectopic meiosis

  1. Sperm Chromatin-Induced Ectopic Polar Body Extrusion in Mouse Eggs after ICSI and Delayed Egg Activation

    PubMed Central

    Deng, Manqi; Li, Rong

    2009-01-01

    Meiotic chromosomes in an oocyte are not only a maternal genome carrier but also provide a positional signal to induce cortical polarization and define asymmetric meiotic division of the oocyte, resulting in polar body extrusion and haploidization of the maternal genome. The meiotic chromosomes play dual function in determination of meiosis: 1) organizing a bipolar spindle formation and 2) inducing cortical polarization and assembly of a distinct cortical cytoskeleton structure in the overlying cortex for polar body extrusion. At fertilization, a sperm brings exogenous paternal chromatin into the egg, which induces ectopic cortical polarization at the sperm entry site and leads to a cone formation, known as fertilization cone. Here we show that the sperm chromatin-induced fertilization cone formation is an abortive polar body extrusion due to lack of spindle induction by the sperm chromatin during fertilization. If experimentally manipulating the fertilization process to allow sperm chromatin to induce both cortical polarization and spindle formation, the fertilization cone can be converted into polar body extrusion. This suggests that sperm chromatin is also able to induce polar body extrusion, like its maternal counterpart. The usually observed cone formation instead of ectopic polar body extrusion induced by sperm chromatin during fertilization is due to special sperm chromatin compaction which restrains it from rapid spindle induction and therefore provides a protective mechanism to prevent a possible paternal genome loss during ectopic polar body extrusion. PMID:19787051

  2. Bovine ovarian cells have (pro)renin receptors and prorenin induces resumption of meiosis in vitro.

    PubMed

    Dau, Andressa Minussi Pereira; da Silva, Eduardo Pradebon; da Rosa, Paulo Roberto Antunes; Bastiani, Felipe Tusi; Gutierrez, Karina; Ilha, Gustavo Freitas; Comim, Fabio Vasconcellos; Gonçalves, Paulo Bayard Dias

    2016-07-01

    The discovery of a receptor that binds prorenin and renin in human endothelial and mesangial cells highlights the possible effect of renin-independent prorenin in the resumption of meiosis in oocytes that was postulated in the 1980s.This study aimed to identify the (pro)renin receptor in the ovary and to assess the effect of prorenin on meiotic resumption. The (pro)renin receptor protein was detected in bovine cumulus-oocyte complexes, theca cells, granulosa cells, and in the corpus luteum. Abundant (pro)renin receptor messenger ribonucleic acid (mRNA) was detected in the oocytes and cumulus cells, while prorenin mRNA was identified in the cumulus cells only. Prorenin at concentrations of 10(-10), 10(-9), and 10(-8)M incubated with oocytes co-cultured with follicular hemisections for 15h caused the resumption of oocyte meiosis. Aliskiren, which inhibits free renin and receptor-bound renin/prorenin, at concentrations of 10(-7), 10(-5), and 10(-3)M blocked this effect (P<0.05). To determine the involvement of angiotensin II in prorenin-induced meiosis resumption, cumulus-oocyte complexes and follicular hemisections were treated with prorenin and with angiotensin II or saralasin (angiotensin II antagonist). Prorenin induced the resumption of meiosis independently of angiotensin II. Furthermore, cumulus-oocyte complexes cultured with forskolin (200μM) and treated with prorenin and aliskiren did not exhibit a prorenin-induced resumption of meiosis (P<0.05). Only the oocytes' cyclic adenosine monophosphate levels seemed to be regulated by prorenin and/or forskolin treatment after incubation for 6h. To the best of our knowledge, this is the first study to identify the (pro)renin receptor in ovarian cells and to demonstrate the independent role of prorenin in the resumption of oocyte meiosis in cattle. PMID:27060674

  3. Ectopically tethered CP190 induces large-scale chromatin decondensation

    NASA Astrophysics Data System (ADS)

    Ahanger, Sajad H.; Günther, Katharina; Weth, Oliver; Bartkuhn, Marek; Bhonde, Ramesh R.; Shouche, Yogesh S.; Renkawitz, Rainer

    2014-01-01

    Insulator mediated alteration in higher-order chromatin and/or nucleosome organization is an important aspect of epigenetic gene regulation. Recent studies have suggested a key role for CP190 in such processes. In this study, we analysed the effects of ectopically tethered insulator factors on chromatin structure and found that CP190 induces large-scale decondensation when targeted to a condensed lacO array in mammalian and Drosophila cells. In contrast, dCTCF alone, is unable to cause such a decondensation, however, when CP190 is present, dCTCF recruits it to the lacO array and mediates chromatin unfolding. The CP190 induced opening of chromatin may not be correlated with transcriptional activation, as binding of CP190 does not enhance luciferase activity in reporter assays. We propose that CP190 may mediate histone modification and chromatin remodelling activity to induce an open chromatin state by its direct recruitment or targeting by a DNA binding factor such as dCTCF.

  4. Ectopically tethered CP190 induces large-scale chromatin decondensation

    PubMed Central

    Ahanger, Sajad H.; Günther, Katharina; Weth, Oliver; Bartkuhn, Marek; Bhonde, Ramesh R.; Shouche, Yogesh S.; Renkawitz, Rainer

    2014-01-01

    Insulator mediated alteration in higher-order chromatin and/or nucleosome organization is an important aspect of epigenetic gene regulation. Recent studies have suggested a key role for CP190 in such processes. In this study, we analysed the effects of ectopically tethered insulator factors on chromatin structure and found that CP190 induces large-scale decondensation when targeted to a condensed lacO array in mammalian and Drosophila cells. In contrast, dCTCF alone, is unable to cause such a decondensation, however, when CP190 is present, dCTCF recruits it to the lacO array and mediates chromatin unfolding. The CP190 induced opening of chromatin may not be correlated with transcriptional activation, as binding of CP190 does not enhance luciferase activity in reporter assays. We propose that CP190 may mediate histone modification and chromatin remodelling activity to induce an open chromatin state by its direct recruitment or targeting by a DNA binding factor such as dCTCF. PMID:24472778

  5. Ameliorative Effect of Grape Seed Proanthocyanidin Extract on Cadmium-Induced Meiosis Inhibition During Oogenesis in Chicken Embryos.

    PubMed

    Hou, Fuyin; Xiao, Min; Li, Jian; Cook, Devin W; Zeng, Weidong; Zhang, Caiqiao; Mi, Yuling

    2016-04-01

    Cadmium (Cd) is an environmental endocrine disruptor that has toxic effects on the female reproductive system. Here the ameliorative effect of grape seed proanthocyanidin extract (GSPE) on Cd-induced meiosis inhibition during oogenesis was explored. As compared with controls, chicken embryos exposed to Cd (3 µg/egg) displayed a changed oocyte morphology, decreased number of meiotic germ cells, and decreased expression of the meiotic marker protein γH2AX. Real time RT-PCR also revealed a significant down-regulation in the mRNA expressions of various meiosis-specific markers (Stra8, Spo11, Scp3, and Dmc1) together with those of Raldh2, a retinoic acid (RA) synthetase, and of the receptors (RARα and RARβ). In addition, exposure to Cd increased the production of H2 O2 and malondialdehyde in the ovaries and caused a corresponding reduction in glutathione and superoxide dismutase. Simultaneous supplementation of GSPE (150 µg/egg) markedly alleviated the aforementioned Cd-induced embryotoxic effects by upregulating meiosis-related proteins and gene expressions and restoring the antioxidative level. Collectively, the findings provided novel insights into the underlying mechanism of Cd-induced meiosis inhibition and indicated that GSPE might potentially ameliorate related reproductive disorders. PMID:26799944

  6. ALDH1A1 provides a source of meiosis-inducing retinoic acid in mouse fetal ovaries

    PubMed Central

    Bowles, Josephine; Feng, Chun-Wei; Miles, Kim; Ineson, Jessica; Spiller, Cassy; Koopman, Peter

    2016-01-01

    Substantial evidence exists that during fetal ovarian development in mammals, retinoic acid (RA) induces germ cells to express the pre-meiotic marker Stra8 and enter meiosis, and that these effects are prevented in the fetal testis by the RA-degrading P450 enzyme CYP26B1. Nonetheless, the role of RA has been disputed principally because germ cells in embryos lacking two major RA-synthesizing enzymes, ALDH1A2 and ALDH1A3, remain able to enter meiosis. Here we show that a third RA-synthesizing enzyme, ALDH1A1, is expressed in fetal ovaries, providing a likely source of RA in the absence of ALDH1A2 and ALDH1A3. In ovaries lacking ALDH1A1, the onset of germ cell meiosis is delayed. Our data resolve the conundrum posed by conflicting published data sets and reconfirm the model that meiosis is triggered by endogenous RA in the developing ovary. PMID:26892828

  7. Marshmallow Meiosis.

    ERIC Educational Resources Information Center

    Soderberg, Patti

    1992-01-01

    Presents an activity in which students model the processes of meiosis, fertilization, development, and birth using model creatures called reebops. Students breed reebops to analyze chromosome combinations. Makes recommendations for activity utilization and identifies the strengths of the activity. (MDH)

  8. Retinoic acid induces Sertoli cell paracrine signals for spermatogonia differentiation but cell autonomously drives spermatocyte meiosis

    PubMed Central

    Raverdeau, Mathilde; Gely-Pernot, Aurore; Féret, Betty; Dennefeld, Christine; Benoit, Gérard; Davidson, Irwin; Chambon, Pierre; Mark, Manuel; Ghyselinck, Norbert B.

    2012-01-01

    Direct evidence for a role of endogenous retinoic acid (RA), the active metabolite of vitamin A in the initial differentiation and meiotic entry of spermatogonia, and thus in the initiation of spermatogenesis is still lacking. RA is synthesized by dedicated enzymes, the retinaldehyde dehydrogenases (RALDH), and binds to and activates nuclear RA receptors (RARA, RARB, and RARG) either within the RA-synthesizing cells or in the neighboring cells. In the present study, we have used a combination of somatic genetic ablations and pharmacological approaches in vivo to show that during the first, prepubertal, spermatogenic cycle (i) RALDH-dependent synthesis of RA by Sertoli cells (SC), the supporting cells of the germ cell (GC) lineage, is indispensable to initiate differentiation of A aligned into A1 spermatogonia; (ii) RARA in SC mediates the effects of RA, possibly through activating Mafb expression, a gene whose Drosophila homolog is mandatory to GC differentiation; (iii) RA synthesized by premeiotic spermatocytes cell autonomously induces meiotic initiation through controlling the RAR-dependent expression of Stra8. Furthermore, we show that RA of SC origin is no longer necessary for the subsequent spermatogenic cycles but essential to spermiation. Altogether, our data establish that the effects of RA in vivo on spermatogonia differentiation are indirect, via SC, but direct on meiotic initiation in spermatocytes, supporting thereby the notion that, contrary to the situation in the female, RA is necessary to induce meiosis in the male. PMID:23012458

  9. Ectopic Pregnancy

    MedlinePlus

    ... Education & Events Advocacy For Patients About ACOG Ectopic Pregnancy Home For Patients Search FAQs Ectopic Pregnancy Page ... Ectopic Pregnancy FAQ155, August 2011 PDF Format Ectopic Pregnancy Pregnancy What is an ectopic pregnancy? Who is ...

  10. The role of SRC1 and SRC2 in steroid-induced SDF1 expression in normal and ectopic endometrium.

    PubMed

    Shi, Xiu; Xu, Wei; Dai, Hui-Hua; Sun, Ying; Wang, Xiu-Li

    2014-06-01

    To compare the expression patterns of steroid receptor coactivators (SRCs) and steroid-induced stromal cell-derived factor 1 (CXCL12 (SDF1)) in normal and ectopic endometrium and to explore the roles of NCOA1 (SRC1) and NCOA2 (SRC2) in the steroid-induced CXCL12 expression in normal and ectopic endometrial stromal cells (ESCs). The NCOA1, NCOA2, NCOA3 (SRC3), and CXCL12 (SDF1)α mRNA levels in normal and ectopic endometrium were analyzed by quantitative real-time PCR. Steroid-induced CXCL12 expression was detected by the ELISA method and the chemotactic activity of conditioned supernatant to monocyte was assessed by the Boyden chamber method before and after the silencing of NCOA1 or NCOA2 with siRNA in normal and ectopic ESCs. The expression of NCOA1 and CXCL12 in ectopic endometrium was significantly greater than that in normal endometrium in the secretory phase. Progesterone (P4) was able to significantly inhibit estradiol (E2)-stimulated CXCL12 expression in normal and ectopic ESCs. The inhibitory rate of P4 in ectopic ESCs at 72 and 96 h was significantly lower than that in normal ESCs. Silencing of NCOA1 but not NCOA2 significantly reduced the E2-induced CXCL12 expression in normal and ectopic ESCs. The ability of P4 to inhibit E2-induced CXCL12 expression and monocyte chemotaxis in normal and ectopic ESCs was significantly attenuated when NCOA2 was silenced. NCOA1 plays a necessary role in E2-induced CXCL12 expression and NCOA2 is required for P4 to inhibit the E2-induced CXCL12 production in normal and ectopic endometrium. PMID:24586072

  11. Ectopic Pregnancy

    MedlinePlus

    ... 5 Things to Know About Zika & Pregnancy Ectopic Pregnancy KidsHealth > For Parents > Ectopic Pregnancy Print A A ... lower back pain continue What Causes an Ectopic Pregnancy? An ectopic pregnancy usually happens because a fertilized ...

  12. [Direct cryothermal ablation eliminates conduction of the slow pathway without inducing ectopic rhythms].

    PubMed

    Márquez, Manlio F; Colín, Luis; Iturralde, Pedro; Nava, Santiago; González, Eric; Rodríguez, Gerardo; Gómez, Jorge; Salica, Gabriel; Cossío, Jorge; Hermosillo, Antonio G; Cárdenas, Manuel

    2005-01-01

    Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia is based on the elimination of conduction of slow or fast intranodal pathway. To avoid potential atrioventricular (AV) block, a new technology has been developed, cryothermal ablation. We report a case of AV nodal reentrant tachycardia in whom direct cryoablation, without previous ice mapping, was successfully performed. Interestingly and as previously described, cryotherapy did not induce ectopic rhythms, the conventional surrogate during radiofrequency ablation. PMID:15909749

  13. HMGB1 Induces Secretion of Matrix Vesicles by Macrophages to Enhance Ectopic Mineralization

    PubMed Central

    Chen, Qiang; Bei, Jun-Jie; Liu, Chuan; Feng, Shi-Bin; Zhao, Wei-Bo; Zhou, Zhou; Yu, Zheng-Ping; Du, Xiao-Jun; Hu, Hou-Yuan

    2016-01-01

    Numerous clinical conditions have been linked to ectopic mineralization (EM). This process of pathological biomineralization is complex and not fully elucidated, but thought to be started within matrix vesicles (MVs). We hypothesized that high mobility group box 1 (HMGB1), a cytokine associated with biomineralizing process under physiological and pathological conditions, induces EM via promoting MVs secretion from macrophages. In this study, we found that HMGB1 significantly promoted secretion of MVs from macrophages and subsequently led to mineral deposition in elevated Ca/Pi medium in vitro. Transmission electron microscopy of calcifying MVs showed formation of hydroxyapatite crystals in the vesicle interior. Subcutaneous injection into mice with MVs derived from HMGB1-treated cells showed a greater potential to initiate regional mineralization. Mechanistic experiments revealed that HMGB1 activated neutral sphingomyelinase2 (nSMase2) that involved the receptor for advanced glycation end products (RAGE) and p38 MAPK (upstream of nSMase2). Inhibition of nSMase2 with GW4869 or p38 MAPK with SB-239063 prevented MVs secretion and mineral deposition. Collectively, HMGB1 induces MVs secretion from macrophages at least in part, via the RAGE/p38 MAPK/nSMase2 signaling pathway. Our findings thus reveal a novel mechanism by which HMGB1 induces ectopic mineralization. PMID:27243975

  14. Morphological differences in BMP-2-induced ectopic bone between solid and crushed hyaluronan hydrogel templates.

    PubMed

    Hulsart-Billström, Gry; Piskounova, Sonya; Gedda, Lars; Andersson, Britt-Marie; Bergman, Kristoffer; Hilborn, Jöns; Larsson, Sune; Bowden, Tim

    2013-05-01

    The possibility to affect bone formation by using crushed versus solid hydrogels as carriers for bone morphogenetic protein 2 (BMP-2) was studied. Hydrogels, based on chemical crosslinking between hyaluronic acid and poly(vinyl alcohol) derivatives, were loaded with BMP-2 and hydroxyapatite. Crushed and solid forms of the gels were analyzed both in vitro via a release study using ¹²⁵I radioactive labeling of BMP-2, and in vivo in a subcutaneous ectopic bone model in rats. Dramatically different morphologies were observed for the ectopic bone formed in vivo in the two types of gels, even though virtually identical release profiles were observed in vitro. Solid hydrogels induced formation of a dense bone shell around non-degraded hydrogel, while crushed hydrogels demonstrated a uniform bone formation throughout the entire sample. These results suggest that by crushing the hydrogel, the construct's three-dimensional network becomes disrupted. This could expose unreacted functional groups, making the fragment's surfaces reactive and enable limited chemical fusion between the crushed hydrogel fragments, leading to similar in vitro release profiles. However, in vivo these interactions could be broken by enzymatic activity, creating a macroporous structure that allows easier cell infiltration, thus, facilitating bone formation. PMID:23392969

  15. Ectopic Pregnancy

    MedlinePlus

    ... and how far into the pregnancy she is: Methotrexate Methotrexate is a medicine that stops an ectopic pregnancy ... of ectopic pregnancies can be successfully treated with methotrexate if detected early enough. The rest will require ...

  16. Ectopic Pregnancy

    MedlinePlus

    ... woman is pregnant. If you have an ectopic pregnancy, the fertilized egg grows in the wrong place, ... tubes. The result is usually a miscarriage. Ectopic pregnancy can be a medical emergency if it ruptures. ...

  17. Excess NF-κB induces ectopic odontogenesis in embryonic incisor epithelium.

    PubMed

    Blackburn, J; Kawasaki, K; Porntaveetus, T; Kawasaki, M; Otsuka-Tanaka, Y; Miake, Y; Ota, M S; Watanabe, M; Hishinuma, M; Nomoto, T; Oommen, S; Ghafoor, S; Harada, F; Nozawa-Inoue, K; Maeda, T; Peterková, R; Lesot, H; Inoue, J; Akiyama, T; Schmidt-Ullrich, R; Liu, B; Hu, Y; Page, A; Ramírez, Á; Sharpe, P T; Ohazama, A

    2015-01-01

    Nuclear factor kappa B (NF-κB) signaling plays critical roles in many physiological and pathological processes, including regulating organogenesis. Down-regulation of NF-κB signaling during development results in hypohidrotic ectodermal dysplasia. The roles of NF-κB signaling in tooth development, however, are not fully understood. We examined mice overexpressing IKKβ, an essential component of the NF-κB pathway, under keratin 5 promoter (K5-Ikkβ). K5-Ikkβ mice showed supernumerary incisors whose formation was accompanied by up-regulation of canonical Wnt signaling. Apoptosis that is normally observed in wild-type incisor epithelium was reduced in K5-Ikkβ mice. The supernumerary incisors in K5-Ikkβ mice were found to phenocopy extra incisors in mice with mutations of Wnt inhibitor, Wise. Excess NF-κB activity thus induces an ectopic odontogenesis program that is usually suppressed under physiological conditions. PMID:25376721

  18. Recycling of Acetylcholine Receptors at Ectopic Postsynaptic Clusters Induced by Exogenous Agrin in Living Rats

    PubMed Central

    Brenner, Hans Rudolf; Akaaboune, Mohammed

    2014-01-01

    During the development of the neuromuscular junction, motor axons induce the clustering of acetylcholine receptors (AChRs) and increase their metabolic stability in the muscle membrane. Here, we asked whether the synaptic organizer agrin might regulate the metabolic stability and density of AChRs by promoting the recycling of internalized AChRs, which would otherwise be destined for degradation, into synaptic sites. We show that at nerve-free AChR clusters induced by agrin in extrasynaptic membrane, internalized AChRs are driven back into the ectopic synaptic clusters where they intermingle with pre-existing and new receptors. The extent of AChR recycling depended on the strength of the agrin stimulus, but not on the development of junctional folds, another hallmark of mature postsynaptic membranes. In chronically denervated muscles, in which both AChR stability and recycling are significantly decreased by muscle inactivity, agrin maintained the amount of recycled AChRs at agrin-induced clusters at a level similar to that at denervated original endplates. In contrast, AChRs did not recycle at agrin-induced clusters in C2C12 or primary myotubes. Thus, in muscles in vivo, but not in cultured myotubes, neural agrin promotes the recycling of AChRs and thereby increases their metabolic stability. PMID:25093969

  19. CARBENDAZIM (MBC) DISRUPTS OOCYTE SPINDLE FUNCTION AND INDUCES ANEUPLOIDY IN HAMSTERS EXPOSED DURING FERTILIZATION (MEIOSIS II)

    EPA Science Inventory

    Peri-fertilization exposure to Carbendazim (MBC; a microtubule poison) induces infertility and early pregnancy loss (EPL) in hamsters. resently, both in vivo and in vitro techniques were employed to characterize the effects of MBC on cellular aspects of fertilization in hamsters....

  20. In vitro steroid-induced meiosis in Rhinella arenarum oocytes: role of pre-MPF activation.

    PubMed

    Arias Torres, Ana Josefina; Bühler, Marta Inés; Zelarayán, Liliana Isabel

    2016-04-01

    In this work we showed the relationship between seasonal periods and the response of R. arenarum follicles and oocytes to different steroids. Using in vitro germinal vesicle breakdown (GVBD) assays, we demonstrated that P4 is the main steroid capable of inducing maturation in R. arenarum oocytes and follicles. In the second part of this work we showed that androgens can activate pre-maturation promoting factors (pre-MPFs) such as P4, by cytoplasm microinjection experiments. The results indicated that the steroids assayed induced oocyte and follicle maturation in a dose- and time-dependent manner. In oocytes, P4 was the most efficient steroid as a maturation inducer (EC50 of the reproductive period, 6 nM, EC50 of the non-reproductive period ≅ 30 nM). Androgens (DHEA, dehydroepiandrosterone; T, testosterone; and AD, androstenedione) were less efficient maturation inducers than P4 (EC50 reproductive period ≅ 50, 120 and 600 nM respectively). Similar results were obtained with intact follicles in both seasonal periods. Although the response of follicles to the different androgens was variable, in no case was it above the above the response induced by P4. Independently of the season, oocytes and follicles incubated in P4, P5 and T underwent GVBD after 6-10 h while oocytes and follicles incubated in DHEA and AD matured more slowly. Furthermore, we demonstrated that microinjection of mature cytoplasm from androgen-treated oocytes is sufficient to promote GVBD in immature recipient oocytes (DHEA, 57 ± 12%; AD, 60 ± 8%; T, 56 ± 13%). Thus, androgens such as DHEA, T and AD are as competent as P4 to activate pre-MPF. PMID:26006336

  1. The ectopic expression of Snail in MDBK cells does not induce epithelial-mesenchymal transition

    PubMed Central

    IZAWA, GENYA; KOBAYASHI, WAKAKO; HARAGUCHI, MISAKO; SUDO, AKIHARU; OZAWA, MASAYUKI

    2015-01-01

    Epithelial-mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell-cell junctions and cell polarity, as well as by the acquisition of migratory and invasive properties. However, the precise molecular events that initiate this complex EMT process are poorly understood. Snail expression induces EMT in Madin-Darby canine kidney (MDCK) cells and the human epidermoid carcinoma cell line, A431. Snail is a zinc finger transcription factor and triggers EMT by suppressing E-cadherin expression. In the present study, to broaden our knowledge of Snail-induced EMT, we generated stable Snail transfectants using Madin-Darby bovine kidney (MDBK) cells. Contrary to the MDCK or A431 cells examined in our previous studies, the MDBK cells transfected with the Snail construct maintained an epithelial morphology and showed no sign of reduced cell-cell adhesiveness compared to the control cells. Consistent with these observations, the down-regulation of epithelial marker proteins, e.g. E-cadherin and desmoglein, and the upregulation of mesenchymal marker proteins, e.g., N-cadherin and fibronectin, were not detected. Furthermore, the E-cadherin promoter was not methylated. Therefore, in the MDBK cells, the ectopic expression of Snail failed to induce EMT. As previously demonstrated, in MDCK cells, Snail expression is accompanied by the increased expression of other EMT-inducing transcription factors, e.g., Slug and zinc finger E-box-binding homeobox 1 (ZEB1). However, the MDBK cells transfected with the Snail construct did not exhibit an increased expression of these factors. Thus, it is possible that the failure to upregulate other EMT-related transcription factors may explain the lack of Snail-mediated induction of EMT in MDBK cells. PMID:25998899

  2. Ectopic automaticity induced in ventricular myocytes by transgenic overexpression of HCN2.

    PubMed

    Oshita, Kensuke; Itoh, Masayuki; Hirashima, Shingo; Kuwabara, Yoshihiro; Ishihara, Keiko; Kuwahara, Koichiro; Nakao, Kazuwa; Kimura, Takeshi; Nakamura, Kei-Ichiro; Ushijima, Kazuo; Takano, Makoto

    2015-03-01

    Hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) are expressed in the ventricles of fetal hearts but are normally down-regulated as development progresses. In the hypertrophied heart, however, these channels are re-expressed and generate a hyperpolarization-activated, nonselective cation current (Ih), which evidence suggests may increase susceptibility to arrhythmia. To test this hypothesis, we generated and analyzed transgenic mice overexpressing HCN2 specifically in their hearts (HCN2-Tg). Under physiological conditions, HCN2-Tg mice exhibited no discernible abnormalities. After the application of isoproterenol (ISO), however, ECG recordings from HCN2-Tg mice showed intermittent atrioventricular dissociation followed by idioventricular rhythm. Consistent with this observation, 0.3 μmol/L ISO-induced spontaneous action potentials (SAPs) in 76% of HCN2-Tg ventricular myocytes. In the remaining 24%, ISO significantly depolarized the resting membrane potential (RMP), and the late repolarization phase of evoked action potentials (APs) was significantly longer than in WT myocytes. Analysis of membrane currents revealed that these differences are attributable to the Ih tail current. These findings suggest HCN2 channel activity reduces the repolarization reserve of the ventricular action potential and increases ectopic automaticity under pathological conditions such as excessive β-adrenergic stimulation. PMID:25562801

  3. Doing the Meiosis Shuffle.

    ERIC Educational Resources Information Center

    Krauskopf, Sara

    1999-01-01

    Presents a game called the Meiosis Shuffle that helps students simulate the process of meiosis in which homologous cards representing chromosomes pair up, line up, and split apart. Students respond well to the simulation and are better able to conceptualize what chromosomes do and how independent assortment causes genetic variation. (CCM)

  4. Main features of meiosis

    SciTech Connect

    1993-12-31

    Chapter 17, outlines the main features of meiosis, beginning with its significance and proceeding through the meiotic stages. Meiosis is the most important modification of mitosis because it is the reduction division that gives rise to the haploid generation in the life cycle. 17 refs., 6 figs.

  5. Abnormal meiosis in tetraploid genotypes of Brachiaria brizantha (Poaceae) induced by colchicine: its implications for breeding.

    PubMed

    Mendes-Bonato, A B; Ferrari Felismino, M; Souza Kaneshima, A M; Pessim, C; Calisto, V; Suely Pagliarini, M; Borges do Valle, C

    2009-01-01

    Meiotic behavior was analyzed in 6 progenies from 3 artificially induced tetraploid (2n = 4x = 36) sexual genotypes (C31, C41, and C48) of the normally apomictic Brachiaria brizantha (Hochst. ex A. Rich.) Stapf., syn. Urochloa brizantha (Hochst. ex A. Rich.) R. Webster. These are key plants to allow intraspecific hybridization of this important forage species, widely used for pastures in the tropics. The percentage of abnormal cells among the plants ranged from 39.8% to 63.2%. In the single plant derived from C48, only the common meiotic abnormalities typical of polyploids were observed, while in plants derived from C31 and C41, a distinct behavior was found. In the majority of cells of those plants, the chromosomes remained scattered in the cytoplasm in the first division, without forming a metaphase plate. This abnormality blocked chromosome movements at anaphase I. Several micronuclei of various sizes were formed and, after the occurrence of an irregular first cytokinesis, the meiocytes progressed normally to the second division, generating polyads with unbalanced microspores. Pollen viability was not correlated with meiotic abnormalities. The importance of these findings to the Brachiaria breeding program is discussed. The sexual progeny of C48 seems most suitable as female parents to be used in intra- and interspecific hybridization. PMID:19433904

  6. Meiosis in male Drosophila

    PubMed Central

    McKee, Bruce D.; Yan, Rihui; Tsai, Jui-He

    2012-01-01

    Meiosis entails sorting and separating both homologous and sister chromatids. The mechanisms for connecting sister chromatids and homologs during meiosis are highly conserved and include specialized forms of the cohesin complex and a tightly regulated homolog synapsis/recombination pathway designed to yield regular crossovers between homologous chromatids. Drosophila male meiosis is of special interest because it dispenses with large segments of the standard meiotic script, particularly recombination, synapsis and the associated structures. Instead, Drosophila relies on a unique protein complex composed of at least two novel proteins, SNM and MNM, to provide stable connections between homologs during meiosis I. Sister chromatid cohesion in Drosophila is mediated by cohesins, ring-shaped complexes that entrap sister chromatids. However, unlike other eukaryotes Drosophila does not rely on the highly conserved Rec8 cohesin in meiosis, but instead utilizes two novel cohesion proteins, ORD and SOLO, which interact with the SMC1/3 cohesin components in providing meiotic cohesion. PMID:23087836

  7. The Cohesin Subunit Rad21 Is Required for Synaptonemal Complex Maintenance, but Not Sister Chromatid Cohesion, during Drosophila Female Meiosis

    PubMed Central

    Lehner, Christian F.; Heidmann, Stefan K.

    2014-01-01

    Replicated sister chromatids are held in close association from the time of their synthesis until their separation during the next mitosis. This association is mediated by the ring-shaped cohesin complex that appears to embrace the sister chromatids. Upon proteolytic cleavage of the α-kleisin cohesin subunit at the metaphase-to-anaphase transition by separase, sister chromatids are separated and segregated onto the daughter nuclei. The more complex segregation of chromosomes during meiosis is thought to depend on the replacement of the mitotic α-kleisin cohesin subunit Rad21/Scc1/Mcd1 by the meiotic paralog Rec8. In Drosophila, however, no clear Rec8 homolog has been identified so far. Therefore, we have analyzed the role of the mitotic Drosophila α-kleisin Rad21 during female meiosis. Inactivation of an engineered Rad21 variant by premature, ectopic cleavage during oogenesis results not only in loss of cohesin from meiotic chromatin, but also in precocious disassembly of the synaptonemal complex (SC). We demonstrate that the lateral SC component C(2)M can interact directly with Rad21, potentially explaining why Rad21 is required for SC maintenance. Intriguingly, the experimentally induced premature Rad21 elimination, as well as the expression of a Rad21 variant with destroyed separase consensus cleavage sites, do not interfere with chromosome segregation during meiosis, while successful mitotic divisions are completely prevented. Thus, chromatid cohesion during female meiosis does not depend on Rad21-containing cohesin. PMID:25101996

  8. The homing of bone marrow MSCs to non-osseous sites for ectopic bone formation induced by osteoinductive calcium phosphate

    PubMed Central

    Song, Guodong; Habibovic, Pamela; Bao, Chongyun; Hu, Jing; van Blitterswijk, Clemens A.; Yuan, Huipin; Chen, Wenchuan; Xu, Hockin H.K.

    2013-01-01

    Osteoinductive biomaterials are promising for bone repair. There is no direct proof that bone marrow mesenchymal stem cells (BMSCs) home to non-osseous sites and participate in ectopic bone formation induced by osteoinductive bioceramics. The objective of this study was to use a sex-mismatched beagle dog model to investigate BMSC homing via blood circulation to participate in ectopic bone formation via osteoinductive biomaterial. BMSCs of male dogs were injected into female femoral marrow cavity. The survival and stable chimerism of donor BMSCs in recipients were confirmed with polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH). Biphasic calcium phosphate (BCP) granules were implanted in dorsal muscles of female dogs. Y chromosomes were detected in samples harvested from female dogs which had received male BMSCs. At 4 weeks, cells with Y-chromosomes were distributed in the new bone matrix throughout the BCP granule implant. At 6 weeks, cells with Y chromosomes were present in newly mineralized woven bone. TRAP positive osteoclast-like cells were observed in 4-week implants, and the number of such cells decreased from 4 to 6 weeks. These results show that osteoprogenitors were recruited from bone marrow and homed to ectopic site to serve as a cell source for calcium phosphate-induced bone formation. In conclusion, BMSCs were demonstrated to migrate from bone marrow through blood circulation to non-osseous bioceramic implant site to contribute to ectopic bone formation in a canine model. BCP induced new bone in muscles without growth factor delivery, showing excellent osteoinductivity that could be useful for bone tissue engineering. PMID:23298780

  9. Details of meiosis

    SciTech Connect

    1993-12-31

    Chapter 18, discusses the details of meiosis, beginning with the structure and number of chiasmata, i.e., the cytological term for two homologous chromosomes forming a bivalent which begin to repel each other until they are held together only at the point of crossing-over. The synaptonemal complex which consists of two lateral elements which contain protein and RNA is also discussed. The chapter concludes with a description of meiosis in polyploids, human meiosis, and the behavior of X and Y chromosomes. 28 refs., 8 figs.

  10. Ectopic heartbeat

    MedlinePlus

    ... recording device, or implanted loop recorder) Coronary angiography ECG Echocardiogram Treatment The following may help reduce ectopic ... section through the middle Heart, front view Electrocardiogram (ECG) References Olgin JE. Approach to the patient with ...

  11. Ectopic pregnancy

    MedlinePlus

    Tubal pregnancy; Cervical pregnancy; Tubal ligation-ectopic pregnancy ... In most pregnancies, the fertilized egg travels through the fallopian tube to the womb (uterus). If the movement of the egg ...

  12. Tinkering with meiosis

    PubMed Central

    Crismani, Wayne; Girard, Chloé; Mercier, Raphael

    2013-01-01

    Meiosis is at the heart of Mendelian heredity. Recently, much progress has been made in the understanding of this process, in various organisms. In the last fifteen years, the functional characterization of numerous genes involved in meiosis has dramatically deepened our knowledge of key events, including recombination, cell cycle and chromosome distribution. Through a constantly advancing tool set and knowledge base, a number of advances have been made that will allow manipulation of meiosis from a plant breeding perspective. This review focuses on the aspects of meiosis that can be tinkered with to create and propagate new varieties. We would like to dedicate this review to the memory of Simon W. Chan (1974-2012) http://www.plb.ucdavis.edu/labs/srchan/ PMID:23136169

  13. The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

    PubMed Central

    Zhang, Qian; Doucet, Michele; Tomlinson, Ryan E; Han, Xiaobin; Quarles, L Darryl; Collins, Michael T; Clemens, Thomas L

    2016-01-01

    Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-1α (HIF-1α) in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-1α mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-1α and FGF23 were co-localized in spindle-shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-1α protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-1α expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-1α inhibitors decreased HIF-1α and FGF23 protein accumulation and inhibited HIF-1α-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-1α consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-1α inhibitor. These results show for the first time that HIF-1α is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-1α activity in TIO contributes to the aberrant FGF23 production in these patients. PMID:27468359

  14. Induced ectopic kinetochore assembly bypasses the requirement for CENP-A nucleosomes

    PubMed Central

    Gascoigne, Karen E.; Takeuchi, Kozo; Suzuki, Aussie; Hori, Tetsuya; Fukagawa, Tatsuo; Cheeseman, Iain M.

    2011-01-01

    Summary Accurate chromosome segregation requires assembly of the multi-protein kinetochore complex at centromeres. Although prior work identified the centromeric histone H3-variant CENP-A as the important upstream factor necessary for centromere specification, in human cells CENP-A is not sufficient for kinetochore assembly. Here, we demonstrate that two constitutive DNA-binding kinetochore components, CENP-C and CENP-T, function to direct kinetochore formation. Replacing the DNA-binding regions of CENP-C and CENP-T with alternate chromosome-targeting domains recruits these proteins to ectopic loci, resulting in CENP-A-independent kinetochore assembly. These ectopic kinetochore-like foci are functional based on the stoichiometric assembly of multiple kinetochore components including the microtubule-binding KMN network, the presence of microtubule attachments, the microtubule-sensitive recruitment of the spindle checkpoint protein Mad2, and the segregation behavior of foci-containing chromosomes. We additionally find that CENP-T phosphorylation regulates the mitotic assembly of both endogenous and ectopic kinetochores. Thus, CENP-C and CENP-T form a critical regulated platform for vertebrate kinetochore assembly. PMID:21529714

  15. Microscopic Procedures for Plant Meiosis.

    ERIC Educational Resources Information Center

    Braselton, James P.

    1997-01-01

    Describes laboratory techniques designed to familiarize students with meiosis and how microscopic preparations of meiosis are made. These techniques require the use of fresh or fixed flowers. Contains 18 references. (DDR)

  16. Ectopic Kidney

    MedlinePlus

    ... Human Development March of Dimes National Office MedlinePlus Kidney and Urologic Disease Organizations Many organizations provide support ... Organizations​​ . (PDF, 345 KB)​​​​​ Alternate Language URL Ectopic Kidney Page Content On this page: What is an ...

  17. Ectopic Pregnancy

    MedlinePlus

    ... to check your levels of human chorionic gonadotropin (hCG). hCG is a hormone that is produced by the ... an ectopic pregnancy, you may have a low hCG level. Your doctor may also want to perform ...

  18. Enhanced bone morphogenetic protein-2-induced ectopic and orthotopic bone formation by intermittent parathyroid hormone (1-34) administration.

    PubMed

    Kempen, Diederik H R; Lu, Lichun; Hefferan, Theresa E; Creemers, Laura B; Heijink, Andras; Maran, Avudaiappan; Dhert, Wouter J A; Yaszemski, Michael J

    2010-12-01

    Bone morphogenetic proteins (BMPs) play a central role in local bone regeneration strategies, whereas the anabolic features of parathyroid hormone (PTH) are particularly appealing for the systemic treatment of generalized bone loss. The aim of the current study was to investigate whether local BMP-2-induced bone regeneration could be enhanced by systemic administration of PTH (1-34). Empty or BMP-2-loaded poly(lactic-co glycolic acid)/poly(propylene fumarate)/gelatin composites were implanted subcutaneously and in femoral defects in rats (n = 9). For the orthotopic site, empty defects were also tested. Each of the conditions was investigated in combination with daily administered subcutaneous PTH (1-34) injections in the neck. After 8 weeks of implantation, bone mineral density (BMD) and bone volume were analyzed using microcomputed tomography and histology. Ectopic bone formation and almost complete healing of the femoral defect were only seen in rats that received BMP-2-loaded composites. Additional treatment of the rats with PTH (1-34) resulted in significantly (p < 0.05) enhanced BMD and bone volume in the BMP-2 composites at both implantation sites. Despite its effect on BMD in the humerus and vertebra, PTH (1-34) treatment had no significant effect on BMD and bone volume in the empty femoral defects and the ectopically or orthotopically implanted empty composites. Histological analysis showed that the newly formed bone had a normal woven and trabecular appearance. Overall, this study suggests that intermittent administration of a low PTH dose alone has limited potential to enhance local bone regeneration in a critical-sized defect in rats. However, when combined with local BMP-2-releasing scaffolds, PTH administration significantly enhanced osteogenesis in both ectopic and orthotopic sites. PMID:20666615

  19. Aquaporin 5 Plays a Role in Estrogen-Induced Ectopic Implantation of Endometrial Stromal Cells in Endometriosis

    PubMed Central

    Jiang, Xiu Xiu; Fei, Xiang Wei; Zhao, Li; Ye, Xiao Lei; Xin, Liao Bin; Qu, Yang; Xu, Kai Hong; Wu, Rui Jin; Lin, Jun

    2015-01-01

    Aquaporin 5 (AQP5) participates in the migration of endometrial cells. Elucidation of the molecular mechanisms associated with AQP5-mediated, migration of endometrial cells may contribute to a better understanding of endometriosis. Our objectives included identifying the estrogen-response element (ERE) in the promoter region of the AQP5 gene, and, investigating the effects of AQP5 on ectopic implantation of endometrial cells. Luciferase reporter assays and electrophoretic mobility shift assay (EMSA) identified the ERE-like motif in the promoter region of the AQP5 gene. After blocking and up-regulating estradiol (E2) levels, we analysed the expression of AQP5 in endometrial stromal (ES) cells. After blocking E2 /or phosphatidylinositol 3 kinase(PI3K), we analysed the role of AQP5 in signaling pathways. We constructed an AQP5, shRNA, lentiviral vector to knock out the AQP5 gene in ES cells. After knock-out of the AQP5 gene, we studied the role of AQP5 in cell invasion, proliferation, and the formation of ectopic endometrial implants in female mice. We identified an estrogen-response element in the promoter region of the AQP5 gene. Estradiol (E2) increased AQP5 expression in a dose-dependent fashion, that was blocked by ICI182,780(an estrogen receptor inhibitor). E2 activated PI3K /protein kinase B(AKT) pathway (PI3K/AKT), that, in turn, increased AQP5 expression. LY294002(PI3K inhibitor) attenuated estrogen-enhanced, AQP5 expression. Knock-out of the AQP5 gene with AQP5 shRNA lentiviral vector significantly inhibited E2-enhanced invasion, proliferation of ES cells and formation of ectopic implants. Estrogen induces AQP5 expression by activating ERE in the promoter region of the AQP5gene, activates the PI3K/AKT pathway, and, promotes endometrial cell invasion and proliferation. These results provide new insights into some of the mechanisms that may underpin the development of deposits of ectopic endometrium. PMID:26679484

  20. Ectopic ERK Expression Induces Phenotypic Conversion of C10 Cells and Alters DNA Methyltransferase Expression

    SciTech Connect

    Sontag, Ryan L.; Weber, Thomas J.

    2012-05-04

    In some model systems constitutive extracellular signal regulated kinase (ERK) activation is sufficient to promote an oncogenic phenotype. Here we investigate whether constitutive ERK expression influences phenotypic conversion in murine C10 type II alveolar epithelial cells. C10 cells were stably transduced with an ERK1-green fluorescent protein (ERK1-GFP) chimera or empty vector and ectopic ERK expression was associated with the acquisition of soft agar focus-forming potential in late passage, but not early passage cells. Late passage ERK1-GFP cells exhibited a significant increase in the expression of DNA methyl transferases (DNMT1 and 3b) and a marked increase in sensitivity to 5-azacytidine (5-azaC)-mediated toxicity, relative to early passage ERK1-GFP cells and vector controls. The expression of xeroderma pigmentosum complementation group A (XPA) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were significantly increased in late passage cells, suggesting enhanced DNA damage recognition and repair activity which we interpret as a reflection of genomic instability. Phospho-ERK levels were dramatically decreased in late passage ERK1-GFP cells, relative to early passage and vector controls, and phospho-ERK levels were restored by treatment with sodium orthovanadate, indicating a role for phosphatase activity in this response. Collectively these observations suggest that ectopic ERK expression promotes phenotypic conversion of C10 cells that is associated with latent effects on epigenetic programming and phosphatase activities.

  1. Evolutionary mysteries in meiosis.

    PubMed

    Lenormand, Thomas; Engelstädter, Jan; Johnston, Susan E; Wijnker, Erik; Haag, Christoph R

    2016-10-19

    Meiosis is a key event of sexual life cycles in eukaryotes. Its mechanistic details have been uncovered in several model organisms, and most of its essential features have received various and often contradictory evolutionary interpretations. In this perspective, we present an overview of these often 'weird' features. We discuss the origin of meiosis (origin of ploidy reduction and recombination, two-step meiosis), its secondary modifications (in polyploids or asexuals, inverted meiosis), its importance in punctuating life cycles (meiotic arrests, epigenetic resetting, meiotic asymmetry, meiotic fairness) and features associated with recombination (disjunction constraints, heterochiasmy, crossover interference and hotspots). We present the various evolutionary scenarios and selective pressures that have been proposed to account for these features, and we highlight that their evolutionary significance often remains largely mysterious. Resolving these mysteries will likely provide decisive steps towards understanding why sex and recombination are found in the majority of eukaryotes.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'. PMID:27619705

  2. A 140-Bp-Long Palindromic Sequence Induces Double-Strand Breaks during Meiosis in the Yeast Saccharomyces Cerevisiae

    PubMed Central

    Nag, D. K.; Kurst, A.

    1997-01-01

    Palindromic sequences have the potential to form hairpin or cruciform structures, which are putative substrates for several nucleases and mismatch repair enzymes. A genetic method was developed to detect such structures in vivo in the yeast Saccharomyces cerevisiae. Using this method we previously showed that short hairpin structures are poorly repaired by the mismatch repair system in S. cerevisiae. We show here that mismatches, when present in the stem of the hairpin structure, are not processed by the repair machinery, suggesting that they are treated differently than those in the interstrand base-paired duplex DNA. A 140-bp-long palindromic sequence, on the contrary, acts as a meiotic recombination hotspot by generating a site for a double-strand break, an initiator of meiotic recombination. We suggest that long palindromic sequences undergo cruciform extrusion more readily than short ones. This cruciform structure then acts as a substrate for structure-specific nucleases resulting in the formation of a double-strand break during meiosis in yeast. In addition, we show that residual repair of the short hairpin structure occurs in an MSH2-independent pathway. PMID:9215890

  3. Yeast meiotic mutants proficient for the induction of ectopic recombination.

    PubMed Central

    Engebrecht, J; Masse, S; Davis, L; Rose, K; Kessel, T

    1998-01-01

    A screen was designed to identify Saccharomyces cerevisiae mutants that were defective in meiosis yet proficient for meiotic ectopic recombination in the return-to-growth protocol. Seven mutants alleles were isolated; two are important for chromosome synapsis (RED1, MEK1) and five function independently of recombination (SPO14, GSG1, SPOT8/MUM2, 3, 4). Similar to the spoT8-1 mutant, mum2 deletion strains do not undergo premeiotic DNA synthesis, arrest prior to the first meiotic division and fail to sporulate. Surprisingly, although DNA replication does not occur, mum2 mutants are induced for high levels of ectopic recombination. gsg1 diploids are reduced in their ability to complete premeiotic DNA synthesis and the meiotic divisions, and a small percentage of cells produce spores. mum3 mutants sporulate poorly and the spores produced are inviable. Finally, mum4-1 mutants produce inviable spores. The meiotic/sporulation defects of gsg1, mum2, and mum3 are not relieved by spo11 or spo13 mutations, indicating that the mutant defects are not dependent on the initiation of recombination or completion of both meiotic divisions. In contrast, the spore inviability of the mum4-1 mutant is rescued by the spo13 mutation. The mum4-1 spo13 mutant undergoes a single, predominantly equational division, suggesting that MUM4 functions at or prior to the first meiotic division. Although recombination is variably affected in the gsg1 and mum mutants, we hypothesize that these mutants define genes important for aspects of meiosis not directly related to recombination. PMID:9504908

  4. Hemorrhagic ascites from spontaneous ectopic mesenteric varices rupture in NASH induced cirrhosis and successful outcome: A case report

    PubMed Central

    Edula, Raja GR; Qureshi, Kamran; Khallafi, Hicham

    2014-01-01

    Bleeding from gastro-esophageal varices can often present as the first decompensating event in patients with cirrhosis. This can be a potentially life threatening event associated with a 15%-20% early mortality. We present a rare case of new onset ascites due to intra-abdominal hemorrhage from ruptured mesenteric varices; in a 37 years old male with newly diagnosed nonalcoholic steatohepatitis induced cirrhosis as the first decompensating event. The patient was successfully resuscitated with emergent evacuation of ascites for diagnosis, identification and control of bleeding mesenteric varices and eventually orthotopic liver transplantation with successful outcome. Various clinical presentations, available treatment options and outcomes of ectopic variceal bleeding are discussed in this report. PMID:25009406

  5. Turning Meiosis into Mitosis

    PubMed Central

    d'Erfurth, Isabelle; Jolivet, Sylvie; Froger, Nicole; Catrice, Olivier; Novatchkova, Maria; Mercier, Raphaël

    2009-01-01

    Apomixis, or asexual clonal reproduction through seeds, is of immense interest due to its potential application in agriculture. One key element of apomixis is apomeiosis, a deregulation of meiosis that results in a mitotic-like division. We isolated and characterised a novel gene that is directly involved in controlling entry into the second meiotic division. By combining a mutation in this gene with two others that affect key meiotic processes, we created a genotype called MiMe in which meiosis is totally replaced by mitosis. The obtained plants produce functional diploid gametes that are genetically identical to their mother. The creation of the MiMe genotype and apomeiosis phenotype is an important step towards understanding and engineering apomixis. PMID:19513101

  6. Delivery of rhBMP-2 Plasmid DNA Complexes via a PLLA/Collagen Electrospun Scaffold Induces Ectopic Bone Formation.

    PubMed

    Zhao, Xia; Komatsu, David E; Hadjiargyrou, Michael

    2016-06-01

    The development of effective strategies for gene delivery is a critical goal in DNA-based tissue engineering. Previously, our laboratory utilized the process of electrospinning to fabricate plasmid DNA-based polymeric scaffolds. Although there lease of DNA was robust, the in vitro transfection efficiency was low. In order to optimize these results, we recently modified our approach and utilized a strategy to adsorb plasmid DNA transfection complexes onto a PLLA/Collagen I electrospun scaffold for the delivery of recombinant human Bone Morphogenetic Protein-2 (rhBMP-2). BMP-2 was selected since it is currently clinically used to stimulate osteogenesis. Initially, we tested this approach using β-gal plasmid DNA complexes adsorbed onto PLLA/Collagen I scaffolds and obtained a transfection efficiency of 41% of that of the positive control (over 90%, DNA complexes in solution). Next, we utilized the same approach using the rhBMP-2 plasmid DNA complexes with the pre-osteoblastic. cell line, MC3T3, and detected robust (13-fold) expression of rhBMP-2 mRNA following transfection. Lastly, a mouse muscle pouch model was used to evaluate in vivo gene delivery efficacy and ectopic bone inducing capability of the scaffold adsorbed rhBMP-2 transfection complexes. Results showed that both rhBMP-2mRNA and protein were expressed and stimulated some ectopic bone formation. As such, adsorption of plasmid DNA complexes can be an effective strategy for tissue engineering in vivo, but further research is required to optimize our approach and obtain a clinically meaningful tissue response. PMID:27319221

  7. Transvection in the Drosophila Ultrabithorax Gene: A Cbx(1) Mutant Allele Induces Ectopic Expression of a Normal Allele in Trans

    PubMed Central

    Castelli-Gair, J. E.; Micol, J. L.; Garcia-Bellido, A.

    1990-01-01

    In wild-type Drosophila melanogaster larvae, the Ultrabithorax (Ubx) gene is expressed in the haltere imaginal discs but not in the majority of cells of the wing imaginal discs. Ectopic expression of the Ubx gene in wing discs can be elicited by the presence of Contrabithorax (Cbx) gain-of-function alleles of the Ubx gene or by loss-of-function mutations in Polycomb (Pc) or in other trans-regulatory genes which behave as repressors of Ubx gene activity. Several Ubx loss-of-function alleles cause the absence of detectable Ubx proteins (UBX) or the presence of truncated UBX lacking the homeodomain. We have compared adult wing phenotypes with larval wing disc UBX patterns in genotypes involving double mutant chromosomes carrying in cis one of those Ubx mutations and the Cbx(1) mutation. We show that such double mutant genes are (1) active in the same cells in which the single mutant Cbx(1) is expressed, although they are unable to yield functional proteins, and (2) able to induce ectopic expression of a normal homologous Ubx allele in a part of the cells in which the single mutant Cbx(1) is active. That induction is conditional upon pairing of the homologous chromosomes (the phenomenon known as transvection), and it is not mediated by UBX. Depletion of Pc gene products by Pc(3) mutation strongly enhances the induction phenomenon, as shown by (1) the increase of the number of wing disc cells in which induction of the homologous allele is detectable, and (2) the induction of not only a paired normal allele but also an unpaired one. PMID:2121595

  8. Atypical ploidy cycles, Spo11, and the evolution of meiosis.

    PubMed

    Bloomfield, Gareth

    2016-06-01

    The Spo11 protein induces DNA double strand breaks before the first division of meiosis, enabling the formation of the chiasmata that physically link homologous chromosomes as they align. Spo11 is an ancient and well conserved protein, related in sequence and structure to a DNA topoisomerase subunit found in Archaea as well as a subset of eukaryotes. However the origins of its meiotic function are unclear. This review examines some apparent exceptions to the rule that Spo11 activity is specific to, and required for meiosis. Spo11 appears to function in the context of unusual forms of ploidy reduction in some protists and fungi. One lineage of amoebae, the dictyostelids, is thought to undergo meiosis during its sexual cycle despite having lost Spo11 entirely. Further experimental characterisation of these and other non-canonical ploidy cycling mechanisms may cast light of the evolution of meiosis. PMID:26811992

  9. Dexamethasone Enhances Osteogenic Differentiation of Bone Marrow- and Muscle-Derived Stromal Cells and Augments Ectopic Bone Formation Induced by Bone Morphogenetic Protein-2

    PubMed Central

    Yuasa, Masato; Yamada, Tsuyoshi; Taniyama, Takashi; Masaoka, Tomokazu; Xuetao, Wei; Yoshii, Toshitaka; Horie, Masaki; Yasuda, Hiroaki; Uemura, Toshimasa; Okawa, Atsushi; Sotome, Shinichi

    2015-01-01

    We evaluated whether dexamethasone augments the osteogenic capability of bone marrow-derived stromal cells (BMSCs) and muscle tissue-derived stromal cells (MuSCs), both of which are thought to contribute to ectopic bone formation induced by bone morphogenetic protein-2 (BMP-2), and determined the underlying mechanisms. Rat BMSCs and MuSCs were cultured in growth media with or without 10-7 M dexamethasone and then differentiated under osteogenic conditions with dexamethasone and BMP-2. The effects of dexamethasone on cell proliferation and osteogenic differentiation, and also on ectopic bone formation induced by BMP-2, were analyzed. Dexamethasone affected not only the proliferation rate but also the subpopulation composition of BMSCs and MuSCs, and subsequently augmented their osteogenic capacity during osteogenic differentiation. During osteogenic induction by BMP-2, dexamethasone also markedly affected cell proliferation in both BMSCs and MuSCs. In an in vivo ectopic bone formation model, bone formation in muscle-implanted scaffolds containing dexamethasone and BMP-2 was more than two fold higher than that in scaffolds containing BMP-2 alone. Our results suggest that dexamethasone potently enhances the osteogenic capability of BMP-2 and may thus decrease the quantity of BMP-2 required for clinical application, thereby reducing the complications caused by excessive doses of BMP-2. Highlights: 1. Dexamethasone induced selective proliferation of bone marrow- and muscle-derived cells with higher differentiation potential. 2. Dexamethasone enhanced the osteogenic capability of bone marrow- and muscle-derived cells by altering the subpopulation composition. 3. Dexamethasone augmented ectopic bone formation induced by bone morphogenetic protein-2. PMID:25659106

  10. Two DNA repair and recombination genes in Saccharomyces cerevisiae, RAD52 and RAD54, are induced during meiosis

    SciTech Connect

    Cole, G.M.; Mortimer, R.K. ); Schild, D. )

    1989-07-01

    The DNA repair and recombination genes of Saccharomyces cerevisiae, RAD52 and RAD54, were transcriptionally induced approximately 10- to 15-fold in sporulating MATa/{alpha} cells. Congenic MATa/a cells, which did not sporulate, did not show similar increases. Assays of {beta}-galactosidase activity in strains harboring either a RAD52- or RAD54-lacZ gene fusion indicated that this induction occurred at a time concomitant with a commitment to meiotic recombination, as measured by prototroph formation from his1 heteroalleles.

  11. Ectopic expression of Zmiz1 induces cutaneous squamous cell malignancies in a mouse model of cancer

    PubMed Central

    Rogers, Laura M.; Riordan, Jesse D.; Swick, Brian L.; Meyerholz, David K.; Dupuy, Adam J.

    2013-01-01

    Cutaneous squamous cell carcinoma (SCC) is the second most common form of cancer in the human population, yet the underlying genetic mechanisms contributing to the disease are not well understood. We recently identified Zmiz1 as a candidate oncogene in non-melanoma skin cancer through a transposon mutagenesis screen. Here we show that transposon-induced mutations in Zmiz1 drive expression of a truncated transcript that is similar to an alternative endogenous ZMIZ1 transcript found to be overexpressed in human SCCs relative to normal skin. We also describe an original mouse model of invasive keratoacanthoma driven by skin-specific expression of the truncated Zmiz1 transcript. Unlike most mouse models, Zmiz1-induced skin tumors develop rapidly and in the absence of promoting agents such as phorbol esters. Additionally, we found that the alternative Zmiz1 isoform has greater protein stability than its full-length counterpart. Finally, we provide evidence that ZMIZ1 is overexpressed in a significant percentage of human breast, ovarian, and colon cancers in addition to human SCCs, suggesting ZMIZ1 may play a broader role in epithelial cancers. PMID:23426136

  12. Paclitaxel-induced epithelial damage and ectopic MMP-13 expression promotes neurotoxicity in zebrafish

    PubMed Central

    Lisse, Thomas S.; Middleton, Leah J.; Pellegrini, Adriana D.; Martin, Paige B.; Spaulding, Emily L.; Lopes, Olivia; Brochu, Elizabeth A.; Carter, Erin V.; Waldron, Ashley; Rieger, Sandra

    2016-01-01

    Paclitaxel is a microtubule-stabilizing chemotherapeutic agent that is widely used in cancer treatment and in a number of curative and palliative regimens. Despite its beneficial effects on cancer, paclitaxel also damages healthy tissues, most prominently the peripheral sensory nervous system. The mechanisms leading to paclitaxel-induced peripheral neuropathy remain elusive, and therapies that prevent or alleviate this condition are not available. We established a zebrafish in vivo model to study the underlying mechanisms and to identify pharmacological agents that may be developed into therapeutics. Both adult and larval zebrafish displayed signs of paclitaxel neurotoxicity, including sensory axon degeneration and the loss of touch response in the distal caudal fin. Intriguingly, studies in zebrafish larvae showed that paclitaxel rapidly promotes epithelial damage and decreased mechanical stress resistance of the skin before induction of axon degeneration. Moreover, injured paclitaxel-treated zebrafish skin and scratch-wounded human keratinocytes (HEK001) display reduced healing capacity. Epithelial damage correlated with rapid accumulation of fluorescein-conjugated paclitaxel in epidermal basal keratinocytes, but not axons, and up-regulation of matrix-metalloproteinase 13 (MMP-13, collagenase 3) in the skin. Pharmacological inhibition of MMP-13, in contrast, largely rescued paclitaxel-induced epithelial damage and neurotoxicity, whereas MMP-13 overexpression in zebrafish embryos rendered the skin vulnerable to injury under mechanical stress conditions. Thus, our studies provide evidence that the epidermis plays a critical role in this condition, and we provide a previously unidentified candidate for therapeutic interventions. PMID:27035978

  13. Ectopic overexpression of Nanog induces tumorigenesis in non-tumorous fibroblasts.

    PubMed

    Park, Yo Seph; Nemeño, Judee Grace E; Choi, Na Young; Lee, Jeong Ik; Ko, Kisung; Choi, Seung-Cheol; Kim, Wan Seop; Han, Dong Wook; Tapia, Natalia; Ko, Kinarm

    2016-03-01

    Key regulatory genes in pluripotent stem cells are of interest not only as reprogramming factors but also as regulators driving tumorigenesis. Nanog is a transcription factor involved in the maintenance of embryonic stem cells and is one of the reprogramming factors along with Oct4, Sox2, and Lin28. Nanog expression has been detected in different types of tumors, and its expression is a poor prognosis for cancer patients. However, there is no clear evidence that Nanog is functionally involved in tumorigenesis. In this study, we induced overexpression of Nanog in mouse embryonic fibroblast cells and subsequently assessed their morphological changes, proliferation rate, and tumor formation ability. We found that Nanog overexpression induced immortalization of mouse embryonic fibroblast cells (MEFs) and increased their proliferation rate in vitro. We also found that formation of tumors after subcutaneous injection of retroviral-Nanog infected MEFs (N-MEFs) into athymic mouse. Cancer-related genes such as Bmi1 were expressed at high levels in N-MEFs. Hence, our results demonstrate that Nanog is able to transform normal somatic cells into tumor cells. PMID:26733157

  14. Paclitaxel-induced epithelial damage and ectopic MMP-13 expression promotes neurotoxicity in zebrafish.

    PubMed

    Lisse, Thomas S; Middleton, Leah J; Pellegrini, Adriana D; Martin, Paige B; Spaulding, Emily L; Lopes, Olivia; Brochu, Elizabeth A; Carter, Erin V; Waldron, Ashley; Rieger, Sandra

    2016-04-12

    Paclitaxel is a microtubule-stabilizing chemotherapeutic agent that is widely used in cancer treatment and in a number of curative and palliative regimens. Despite its beneficial effects on cancer, paclitaxel also damages healthy tissues, most prominently the peripheral sensory nervous system. The mechanisms leading to paclitaxel-induced peripheral neuropathy remain elusive, and therapies that prevent or alleviate this condition are not available. We established a zebrafish in vivo model to study the underlying mechanisms and to identify pharmacological agents that may be developed into therapeutics. Both adult and larval zebrafish displayed signs of paclitaxel neurotoxicity, including sensory axon degeneration and the loss of touch response in the distal caudal fin. Intriguingly, studies in zebrafish larvae showed that paclitaxel rapidly promotes epithelial damage and decreased mechanical stress resistance of the skin before induction of axon degeneration. Moreover, injured paclitaxel-treated zebrafish skin and scratch-wounded human keratinocytes (HEK001) display reduced healing capacity. Epithelial damage correlated with rapid accumulation of fluorescein-conjugated paclitaxel in epidermal basal keratinocytes, but not axons, and up-regulation of matrix-metalloproteinase 13 (MMP-13, collagenase 3) in the skin. Pharmacological inhibition of MMP-13, in contrast, largely rescued paclitaxel-induced epithelial damage and neurotoxicity, whereas MMP-13 overexpression in zebrafish embryos rendered the skin vulnerable to injury under mechanical stress conditions. Thus, our studies provide evidence that the epidermis plays a critical role in this condition, and we provide a previously unidentified candidate for therapeutic interventions. PMID:27035978

  15. Control of mammalian germ cell entry into meiosis.

    PubMed

    Feng, Chun-Wei; Bowles, Josephine; Koopman, Peter

    2014-01-25

    Germ cells are unique in undergoing meiosis to generate oocytes and sperm. In mammals, meiosis onset is before birth in females, or at puberty in males, and recent studies have uncovered several regulatory steps involved in initiating meiosis in each sex. Evidence suggests that retinoic acid (RA) induces expression of the critical pre-meiosis gene Stra8 in germ cells of the fetal ovary, pubertal testis and adult testis. In the fetal testis, CYP26B1 degrades RA, while FGF9 further antagonises RA signalling to suppress meiosis. Failsafe mechanisms involving Nanos2 may further suppress meiosis in the fetal testis. Here, we draw together the growing knowledge relating to these meiotic control mechanisms, and present evidence that they are co-ordinately regulated and that additional factors remain to be identified. Understanding this regulatory network will illuminate not only how the foundations of mammalian reproduction are laid, but also how mis-regulation of these steps can result in infertility or germline tumours. PMID:24076097

  16. Transient Ectopic Overexpression of Agouti-Signalling Protein 1 (Asip1) Induces Pigment Anomalies in Flatfish

    PubMed Central

    Cal, Rosa; Rotllant, Josep; Cerdá-Reverter, José Miguel

    2012-01-01

    While flatfish in the wild exhibit a pronounced countershading of the dorso-ventral pigment pattern, malpigmentation is commonly observed in reared animals. In fish, the dorso-ventral pigment polarity is achieved because a melanization inhibition factor (MIF) inhibits melanoblast differentiation and encourages iridophore proliferation in the ventrum. A previous work of our group suggested that asip1 is the uncharacterized MIF concerned. In order to further support this hypothesis, we have characterized asip1 mRNAs in both turbot and sole and used deduced peptide alignments to analyze the evolutionary history of the agouti-family of peptides. The putative asip precursors have the characteristics of a secreted protein, displaying a putative hydrophobic signal. Processing of the potential signal peptide produces mature proteins that include an N-terminal region, a basic central domain with a high proportion of lysine residues as well as a proline-rich region that immediately precedes the C-terminal poly-cysteine domain. The expression of asip1 mRNA in the ventral area was significantly higher than in the dorsal region. Similarly, the expression of asip1 within the unpigmented patches in the dorsal skin of pseudoalbino fish was higher than in the pigmented dorsal regions but similar to those levels observed in the ventral skin. In addition, the injection/electroporation of asip1 capped mRNA in both species induced long term dorsal skin paling, suggesting the inhibition of the melanogenic pathways. The data suggest that fish asip1 is involved in the dorsal-ventral pigment patterning in adult fish, where it induces the regulatory asymmetry involved in precursor differentiation into mature chromatophore. Adult dorsal pseudoalbinism seems to be the consequence of the expression of normal developmental pathways in an inaccurate position that results in unbalanced asip1 production levels. This, in turn, generates a ventral-like differentiation environment in dorsal regions

  17. A phenotypic screen in zebrafish identifies a novel small-molecule inducer of ectopic tail formation suggestive of alterations in non-canonical Wnt/PCP signaling.

    PubMed

    Gebruers, Evelien; Cordero-Maldonado, María Lorena; Gray, Alexander I; Clements, Carol; Harvey, Alan L; Edrada-Ebel, Ruangelie; de Witte, Peter A M; Crawford, Alexander D; Esguerra, Camila V

    2013-01-01

    Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a zebrafish-based phenotypic screen of over 3000 plant-derived secondary metabolite extracts with the goal of identifying novel small-molecule modulators of the BMP and Wnt signaling pathways. One of the bioactive plant extracts identified in this screen - Jasminum gilgianum, an Oleaceae species native to Papua New Guinea - induced ectopic tails during zebrafish embryonic development. As ectopic tail formation occurs when BMP or non-canonical Wnt signaling is inhibited during the tail protrusion process, we suspected a constituent of this extract to act as a modulator of these pathways. A bioassay-guided isolation was carried out on the basis of this zebrafish phenotype, identifying para-coumaric acid methyl ester (pCAME) as the active compound. We then performed an in-depth phenotypic analysis of pCAME-treated zebrafish embryos, including a tissue-specific marker analysis of the secondary tails. We found pCAME to synergize with the BMP-inhibitors dorsomorphin and LDN-193189 in inducing ectopic tails, and causing convergence-extension defects in compound-treated embryos. These results indicate that pCAME may interfere with non-canonical Wnt signaling. Inhibition of Jnk, a downstream target of Wnt/PCP signaling (via morpholino antisense knockdown and pharmacological inhibition with the kinase inhibitor SP600125) phenocopied pCAME-treated embryos. However, immunoblotting experiments revealed pCAME to not directly inhibit Jnk-mediated phosphorylation of c-Jun, suggesting additional targets of SP600125, and/or other pathways, as possibly being involved in the ectopic tail formation activity of pCAME. Further investigation of pCAME's mechanism of action will help determine this compound's pharmacological utility. PMID:24349481

  18. Ectopic Overexpression of The Transcription Factor OsGLK1 Induces Chloroplast Development in Non-Green Rice Cells

    PubMed Central

    Nakamura, Hidemitsu; Muramatsu, Masayuki; Hakata, Makoto; Ueno, Osamu; Nagamura, Yoshiaki; Hirochika, Hirohiko; Takano, Makoto; Ichikawa, Hiroaki

    2009-01-01

    For systematic and genome-wide analyses of rice gene functions, we took advantage of the full-length cDNA overexpresser (FOX) gene-hunting system and generated >12 000 independent FOX-rice lines from >25 000 rice calli treated with the rice-FOX Agrobacterium library. We found two FOX-rice lines generating green calli on a callus-inducing medium containing 2,4-D, on which wild-type rice calli became ivory yellow. In both lines, OsGLK1 cDNA encoding a GARP transcription factor was ectopically overexpressed. Using rice expression-microarray and northern blot analyses, we found that a large number of nucleus-encoded genes involved in chloroplast functions were highly expressed and transcripts of plastid-encoded genes, psaA, psbA and rbcL, increased in the OsGLK1-FOX calli. Transmission electron microscopy showed the existence of differentiated chloroplasts with grana stacks in OsGLK1-FOX calli cells. However, in darkness, OsGLK1-FOX calli did not show a green color or develop grana stacks. Furthermore, we found developed chloroplasts in vascular bundle and bundle sheath cells of coleoptiles and leaves from OsGLK1-FOX seedlings. The OsGLK1-FOX calli exhibited high photosynthetic activity and were able to grow on sucrose-depleted media, indicating that developed chloroplasts in OsGLK1-FOX rice calli are functional and active. We also observed that the endogenous OsGLK1 mRNA level increased synchronously with the greening of wild-type calli after transfer to plantlet regeneration medium. These results strongly suggest that OsGLK1 regulates chloroplast development under the control of light and phytohormones, and that it is a key regulator of chloroplast development. PMID:19808806

  19. MAPK Phosphatase AP2C3 Induces Ectopic Proliferation of Epidermal Cells Leading to Stomata Development in Arabidopsis

    PubMed Central

    Kazanaviciute, Vaiva; Magyar, Zoltan; Ayatollahi, Zahra; Unterwurzacher, Verena; Choopayak, Chonnanit; Boniecka, Justyna; Murray, James A. H.; Bogre, Laszlo; Meskiene, Irute

    2010-01-01

    In plant post-embryonic epidermis mitogen-activated protein kinase (MAPK) signaling promotes differentiation of pavement cells and inhibits initiation of stomata. Stomata are cells specialized to modulate gas exchange and water loss. Arabidopsis MAPKs MPK3 and MPK6 are at the core of the signaling cascade; however, it is not well understood how the activity of these pleiotropic MAPKs is constrained spatially so that pavement cell differentiation is promoted only outside the stomata lineage. Here we identified a PP2C-type phosphatase termed AP2C3 (Arabidopsis protein phosphatase 2C) that is expressed distinctively during stomata development as well as interacts and inactivates MPK3, MPK4 and MPK6. AP2C3 co-localizes with MAPKs within the nucleus and this localization depends on its N-terminal extension. We show that other closely related phosphatases AP2C2 and AP2C4 are also MAPK phosphatases acting on MPK6, but have a distinct expression pattern from AP2C3. In accordance with this, only AP2C3 ectopic expression is able to stimulate cell proliferation leading to excess stomata development. This function of AP2C3 relies on the domains required for MAPK docking and intracellular localization. Concomitantly, the constitutive and inducible AP2C3 expression deregulates E2F-RB pathway, promotes the abundance and activity of CDKA, as well as changes of CDKB1;1 forms. We suggest that AP2C3 downregulates the MAPK signaling activity to help maintain the balance between differentiation of stomata and pavement cells. PMID:21203456

  20. Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model

    PubMed Central

    Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P

    2011-01-01

    Abstract Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29+, CD44+ and CD166+ after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. PMID

  1. Black hole meiosis

    NASA Astrophysics Data System (ADS)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  2. Effects of the hypoxia-inducible factor-1 inhibitor echinomycin on vascular endothelial growth factor production and apoptosis in human ectopic endometriotic stromal cells.

    PubMed

    Tsuzuki, Tomoko; Okada, Hidetaka; Shindoh, Hisayuu; Shimoi, Kayo; Nishigaki, Akemi; Kanzaki, Hideharu

    2016-04-01

    Recent evidence points to a possible role for hypoxia-inducible factor (HIF)-1 in the pathogenesis and development of endometriosis. The objectives of this study were to investigate the critical role of HIF-1 in endometriosis and the effect of the HIF-1 inhibitor echinomycin on human ectopic endometriotic stromal cells (eESCs). Ectopic endometriotic tissues were obtained from 20 patients, who received an operation for ovarian endometriomas. We examined vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) production, HIF-1 expression, cell proliferation and apoptosis of eESCs. Cobalt chloride (CoCl2) significantly induced expression of HIF-1α protein and VEGF production in a time-dependent manner in eESCs, but reduced SDF-1 production. VEGF production was significantly suppressed by treatment of 100 nM echinomycin without causing cell toxicity, but 0.1-10 nM echinomycin or 100 nM progestin had no significant effect. SDF-1 production was not affected by echinomycin treatment at any dose. Echinomycin inhibited cell proliferation and induced apoptotic cell death of the eESCs, and significantly inhibited expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL. Echinomycin inhibits VEGF production and induces apoptosis of eESCs by suppression of Bcl-2 and Bcl-xL. These findings suggest the unique therapeutic potential for echinomycin as an inhibitor of HIF-1 activation for endometriosis treatment. PMID:26654708

  3. Development of a Meiosis Concept Inventory

    ERIC Educational Resources Information Center

    Kalas, Pamela; O'Neill, Angie; Pollock, Carol; Birol, Gulnur

    2013-01-01

    We have designed, developed, and validated a 17-question Meiosis Concept Inventory (Meiosis CI) to diagnose student misconceptions on meiosis, which is a fundamental concept in genetics. We targeted large introductory biology and genetics courses and used published methodology for question development, which included the validation of questions by…

  4. The colocalization transition of homologous chromosomes at meiosis.

    PubMed

    Nicodemi, Mario; Panning, Barbara; Prisco, Antonella

    2008-06-01

    Meiosis is the specialized cell division required in sexual reproduction. During its early stages, in the mother cell nucleus, homologous chromosomes recognize each other and colocalize in a crucial step that remains one of the most mysterious of meiosis. Starting from recent discoveries on the system molecular components and interactions, we discuss a statistical mechanics model of chromosome early pairing. Binding molecules mediate long-distance interaction of special DNA recognition sequences and, if their concentration exceeds a critical threshold, they induce a spontaneous colocalization transition of chromosomes, otherwise independently diffusing. PMID:18643306

  5. The colocalization transition of homologous chromosomes at meiosis

    NASA Astrophysics Data System (ADS)

    Nicodemi, Mario; Panning, Barbara; Prisco, Antonella

    2008-06-01

    Meiosis is the specialized cell division required in sexual reproduction. During its early stages, in the mother cell nucleus, homologous chromosomes recognize each other and colocalize in a crucial step that remains one of the most mysterious of meiosis. Starting from recent discoveries on the system molecular components and interactions, we discuss a statistical mechanics model of chromosome early pairing. Binding molecules mediate long-distance interaction of special DNA recognition sequences and, if their concentration exceeds a critical threshold, they induce a spontaneous colocalization transition of chromosomes, otherwise independently diffusing.

  6. Arabidopsis homeodomain-leucine zipper IV proteins promote stomatal development and ectopically induce stomata beyond the epidermis

    PubMed Central

    Peterson, Kylee M.; Shyu, Christine; Burr, Christian A.; Horst, Robin J.; Kanaoka, Masahiro M.; Omae, Minami; Sato, Yutaka; Torii, Keiko U.

    2013-01-01

    The shoot epidermis of land plants serves as a crucial interface between plants and the atmosphere: pavement cells protect plants from desiccation and other environmental stresses, while stomata facilitate gas exchange and transpiration. Advances have been made in our understanding of stomatal patterning and differentiation, and a set of ‘master regulatory’ transcription factors of stomatal development have been identified. However, they are limited to specifying stomatal differentiation within the epidermis. Here, we report the identification of an Arabidopsis homeodomain-leucine zipper IV (HD-ZIP IV) protein, HOMEODOMAIN GLABROUS2 (HDG2), as a key epidermal component promoting stomatal differentiation. HDG2 is highly enriched in meristemoids, which are transient-amplifying populations of stomatal-cell lineages. Ectopic expression of HDG2 confers differentiation of stomata in internal mesophyll tissues and occasional multiple epidermal layers. Conversely, a loss-of-function hdg2 mutation delays stomatal differentiation and, rarely but consistently, results in aberrant stomata. A closely related HD-ZIP IV gene, Arabidopsis thaliana MERISTEM LAYER1 (AtML1), shares overlapping function with HDG2: AtML1 overexpression also triggers ectopic stomatal differentiation in the mesophyll layer and atml1 mutation enhances the stomatal differentiation defects of hdg2. Consistently, HDG2 and AtML1 bind the same DNA elements, and activate transcription in yeast. Furthermore, HDG2 transactivates expression of genes that regulate stomatal development in planta. Our study highlights the similarities and uniqueness of these two HD-ZIP IV genes in the specification of protodermal identity and stomatal differentiation beyond predetermined tissue layers. PMID:23515473

  7. Chromosome segregation in plant meiosis

    PubMed Central

    Zamariola, Linda; Tiang, Choon Lin; De Storme, Nico; Pawlowski, Wojtek; Geelen, Danny

    2014-01-01

    Faithful chromosome segregation in meiosis is essential for ploidy stability over sexual life cycles. In plants, defective chromosome segregation caused by gene mutations or other factors leads to the formation of unbalanced or unreduced gametes creating aneuploid or polyploid progeny, respectively. Accurate segregation requires the coordinated execution of conserved processes occurring throughout the two meiotic cell divisions. Synapsis and recombination ensure the establishment of chiasmata that hold homologous chromosomes together allowing their correct segregation in the first meiotic division, which is also tightly regulated by cell-cycle dependent release of cohesin and monopolar attachment of sister kinetochores to microtubules. In meiosis II, bi-orientation of sister kinetochores and proper spindle orientation correctly segregate chromosomes in four haploid cells. Checkpoint mechanisms acting at kinetochores control the accuracy of kinetochore-microtubule attachment, thus ensuring the completion of segregation. Here we review the current knowledge on the processes taking place during chromosome segregation in plant meiosis, focusing on the characterization of the molecular factors involved. PMID:24987397

  8. Spermatogenesis: The Commitment to Meiosis.

    PubMed

    Griswold, Michael D

    2016-01-01

    Mammalian spermatogenesis requires a stem cell pool, a period of amplification of cell numbers, the completion of reduction division to haploid cells (meiosis), and the morphological transformation of the haploid cells into spermatozoa (spermiogenesis). The net result of these processes is the production of massive numbers of spermatozoa over the reproductive lifetime of the animal. One study that utilized homogenization-resistant spermatids as the standard determined that human daily sperm production (dsp) was at 45 million per day per testis (60). For each human that means ∼1,000 sperm are produced per second. A key to this level of gamete production is the organization and architecture of the mammalian testes that results in continuous sperm production. The seemingly complex repetitious relationship of cells termed the "cycle of the seminiferous epithelium" is driven by the continuous commitment of undifferentiated spermatogonia to meiosis and the period of time required to form spermatozoa. This commitment termed the A to A1 transition requires the action of retinoic acid (RA) on the undifferentiated spermatogonia or prospermatogonia. In stages VII to IX of the cycle of the seminiferous epithelium, Sertoli cells and germ cells are influenced by pulses of RA. These pulses of RA move along the seminiferous tubules coincident with the spermatogenic wave, presumably undergoing constant synthesis and degradation. The RA pulse then serves as a trigger to commit undifferentiated progenitor cells to the rigidly timed pathway into meiosis and spermatid differentiation. PMID:26537427

  9. Generation of human-induced pluripotent stem cells from gut mesentery-derived cells by ectopic expression of OCT4/SOX2/NANOG.

    PubMed

    Li, Yang; Zhao, Hongxi; Lan, Feng; Lee, Andrew; Chen, Liu; Lin, Changsheng; Yao, Yuanqing; Li, Lingsong

    2010-06-01

    Induced pluripotent stem (iPS) cells have been generated from human somatic cells by ectopic expression of defined transcription factors. Application of this approach in human cells may have enormous potential to generate patient-specific pluripotent stem cells. However, traditional methods of reprogramming in human somatic cells involve the use of oncogenes c-MYC and KLF4, which are not applicable to clinical translation. In the present study, we investigated whether human fetal gut mesentery-derived cells (hGMDCs) could be successfully reprogrammed into induced pluripotent stem (iPS) cells by OCT4, SOX2, and NANOG alone. We used lentiviruses to express OCT4, SOX2, NANOG, in hGMDCs, then generated iPS cells that were identified by morphology, presence of pluripotency markers, global gene expression profile, DNA methylation status, capacity to form embryoid bodies (EBs), and terotoma formation. iPS cells resulting from hGMDCs were similar to human embryonic stem (ES) cells in morphology, proliferation, surface markers, gene expression, and epigenetic status of pluripotent cell-specific genes. Furthermore, these cells were able to differentiate into cell types of all three germ layers both in vitro and in vivo, as shown by EB and teratoma formation assays. DNA fingerprinting showed that the human iPS cells were derived from the donor cells, and are not a result of contamination. Our results provide proof that hGMDCs can be reprogrammed into pluripotent cells by ectopic expression of three factors (OCT4, SOX2, and NANOG) without the use of oncogenes c-MYC and KLF4. PMID:20698766

  10. Piwil1 mediates meiosis during spermatogenesis in chicken.

    PubMed

    Xu, Lu; Chang, Guobin; Ma, Teng; Wang, Hongzhi; Chen, Jing; Li, Zhiteng; Guo, Xiaomin; Wan, Fang; Ren, Lichen; Lu, Wei; Chen, Guohong

    2016-03-01

    Piwil1 mediates spermatogenesis and ensures stable cell division rates in germline cells in mammals. However, the involvement of Piwil1 in poultry spermatogenesis and meiosis is poorly understood. In the present study, we used TaqMan RT-qPCR to characterize Piwil1 mRNA expression in different types of spermatogenic cells, including primordial germ cells (PGCs), spermatogonial stem cells (SSCs), spermatogonia cells (Sa), tetraploid cells (Tp), round sperm cells (Rs), mature sperm, and in PGCs treated with retinoic acid. Our results revealed that Piwil1 is differentially expressed during spermatogenesis in chicken. Compared to PGCs, SSCs, Tp, and Sa, Rs cells presented the highest Piwil1 mRNA expression levels. Retinoic acid significantly upregulated Piwil1 and Stra8 mRNA expression as well as Piwil1 levels in chicken PGCs. In addition, retinoic acid induced PGCs to progress through all the meiotic stages, eventually leading to haploid cell formation, which was determined using flow cytometry and western blot analysis. Taken together, our results showed that during spermatogenesis, Piwil1 was first expressed at low levels in germ stem cells, PGCs, and SSCs. Its expression levels increased during later meiosis stages. Finally, no expression was detected in mature sperm after meiosis. Treatment of PGCs with retinoic acid further demonstrated that Piwil1 plays a key role in meiosis during chicken spermatogenesis. PMID:26811260

  11. Ectopic Expression of Ptf1a Induces Spinal Defects, Urogenital Defects, and Anorectal Malformations in Danforth's Short Tail Mice

    PubMed Central

    Matsumoto, Ken-ichirou; Suda, Hiroko; Ando, Takashi; Sei, Akira; Mizuta, Hiroshi; Takagi, Katsumasa; Nakahara, Mai; Muta, Mayumi; Yamada, Gen; Nakagata, Naomi; Iida, Aritoshi; Ikegawa, Shiro; Nakamura, Yusuke; Araki, Masatake; Abe, Kuniya; Yamamura, Ken-ichi

    2013-01-01

    Danforth's short tail (Sd) is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney. PMID:23436999

  12. Endocytosis is essential for dynamic translocation of a syntaxin 1 orthologue during fission yeast meiosis

    PubMed Central

    Kashiwazaki, Jun; Yamasaki, Yuriko; Itadani, Akiko; Teraguchi, Erika; Maeda, Yukari; Shimoda, Chikashi; Nakamura, Taro

    2011-01-01

    Syntaxin is a component of the target soluble N-ethylmaleimide–sensitive factor attachment protein receptor complex, which is responsible for fusion of membrane vesicles at the target membrane. The fission yeast syntaxin 1 orthologue Psy1 is essential for both vegetative growth and spore formation. During meiosis, Psy1 disappears from the plasma membrane (PM) and dramatically relocalizes on the nascent forespore membrane, which becomes the PM of the spore. Here we report the molecular details and biological significance of Psy1 relocalization. We find that, immediately after meiosis I, Psy1 is selectively internalized by endocytosis. In addition, a meiosis-specific signal induced by the transcription factor Mei4 seems to trigger this internalization. The internalization of many PM proteins is facilitated coincident with the initiation of meiosis, whereas Pma1, a P-type ATPase, persists on the PM even during the progression of meiosis II. Ergosterol on the PM is also important for the internalization of PM proteins in general during meiosis. We consider that during meiosis in Schizosaccharomyces pombe cells, the characteristics of endocytosis change, thereby facilitating internalization of Psy1 and accomplishing sporulation. PMID:21832151

  13. Meiosis-activating sterol promotes resumption of meiosis in mouse oocytes cultured in vitro in contrast to related oxysterols.

    PubMed

    Grøndahl, C; Ottesen, J L; Lessl, M; Faarup, P; Murray, A; Grønvald, F C; Hegele-Hartung, C; Ahnfelt-Rønne, I

    1998-05-01

    The sterol 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol (FF-MAS [follicular-fluid meiosis-activating sterol]) from human follicular fluid has recently been identified as a compound that induces the resumption of meiosis. FF-MAS and various oxysterols have been reported to transactivate the orphan receptor LXRalpha. The objective was to determine the biological activity of synthetic FF-MAS on the resumption of meiosis and final maturation of mouse oocytes in vitro. In order to evaluate whether LXRalpha might mediate FF-MAS action on the oocyte, we compared the capability of various compounds to activate LXRalpha-dependent transcription and to induce resumption of meiosis in the oocyte assay. Ovaries were isolated from immature mice primed with FSH 48 h before collection. Naked oocytes (NkO) and cumulus enclosed oocytes (CEO) were isolated from follicles. The oocytes were cultured in two groups, NkO and CEO, respectively, in media containing either 3 mM hypoxanthine, 5 microM IBMX, or 0.100 mM dbcAMP to maintain the oocytes in the germinal vesicle stage. The resumption of meiosis was assessed by the frequency of germinal vesicle breakdown (GVBD) after 24 h of in vitro culture. FF-MAS overcame the meiotic inhibition by hypoxanthine in both the NkO group and CEO group in a dose-dependent manner within the concentration range 0.07-7 microM. FF-MAS displayed similar potency in all inhibitory agents used. Also, FF-MAS significantly increased the formation of polar bodies in both the CEO and NkO group. The oxysterols 22(R)-hydroxycholesterol (a potent ligand for the LXRalpha receptor), 16-hydroxycholesterol, 25-hydroxycholesterol, and 27-hydroxycholesterol, as well as cholesterol, were tested without any significant effect on maturation compared to that of controls. Oxysterols and FF-MAS were observed to activate LXRalpha. In conclusion, the results reported here clearly demonstrate that synthetic FF-MAS exclusively is capable of mediating resumption of meiosis in

  14. Genetic analysis of ectopic circadian clock induction in Drosophila.

    PubMed

    Kilman, Valerie L; Allada, Ravi

    2009-10-01

    Cell-autonomous feedback loops underlie the molecular oscillations that define circadian clocks. In Drosophila the transcription factor Clk activates multiple clock components of feedback loops many of which feed back and regulate Clk expression or activity. Previously the authors evoked similar molecular oscillations in putatively naïve neurons in Drosophila by ectopic expression of a single gene, Clk, suggesting a master regulator function. Using molecular oscillations of the core clock component PERIOD (PER), the authors observed dramatic and widespread molecular oscillations throughout the brain in flies expressing ectopic Clk. Consistent with the master regulator hypothesis, they found that Clk is uniquely capable of inducing ectopic clocks as ectopic induction of other clock components fails to induce circadian rhythms. Clk also induces oscillations even when expression is adult restricted, suggesting that ectopic clocks can even be induced in differentiated cells. However, if transgene expression is discontinued, PER expression disappears, indicating that Clk must be continually active to sustain ectopic clock function. In some cases Clk-mediated PER induction was observed without apparent synchronous cycling, perhaps due to desynchronization of rhythms between clocks or truly cell autonomous arrhythmic PER expression, indicating that additional factors may be necessary for coherent rhythms in cells ectopically expressing Clk. To determine minimal requirements for circadian clock induction by Clk, the authors determined the genetic requirements of ectopic clocks. No ectopic clocks are induced in mutants of Clk's heterodimeric partner cyc. In addition, noncycling PER is observed when ectopic Clk is induced in a cryb mutant background. While other factors may contribute, these results indicate that persistent Clock induction is uniquely capable of broadly inducing ectopic rhythms even in adults, consistent with a special role at the top of a clock gene

  15. Implementation of meiosis prophase I programme requires a conserved retinoid-independent stabilizer of meiotic transcripts

    PubMed Central

    Abby, Emilie; Tourpin, Sophie; Ribeiro, Jonathan; Daniel, Katrin; Messiaen, Sébastien; Moison, Delphine; Guerquin, Justine; Gaillard, Jean-Charles; Armengaud, Jean; Langa, Francina; Toth, Attila; Martini, Emmanuelle; Livera, Gabriel

    2016-01-01

    Sexual reproduction is crucially dependent on meiosis, a conserved, specialized cell division programme that is essential for the production of haploid gametes. Here we demonstrate that fertility and the implementation of the meiotic programme require a previously uncharacterized meiosis-specific protein, MEIOC. Meioc invalidation in mice induces early and pleiotropic meiotic defects in males and females. MEIOC prevents meiotic transcript degradation and interacts with an RNA helicase that binds numerous meiotic mRNAs. Our results indicate that proper engagement into meiosis necessitates the specific stabilization of meiotic transcripts, a previously little-appreciated feature in mammals. Remarkably, the upregulation of MEIOC at the onset of meiosis does not require retinoic acid and STRA8 signalling. Thus, we propose that the complete induction of the meiotic programme requires both retinoic acid-dependent and -independent mechanisms. The latter process involving post-transcriptional regulation likely represents an ancestral mechanism, given that MEIOC homologues are conserved throughout multicellular animals. PMID:26742488

  16. Implementation of meiosis prophase I programme requires a conserved retinoid-independent stabilizer of meiotic transcripts.

    PubMed

    Abby, Emilie; Tourpin, Sophie; Ribeiro, Jonathan; Daniel, Katrin; Messiaen, Sébastien; Moison, Delphine; Guerquin, Justine; Gaillard, Jean-Charles; Armengaud, Jean; Langa, Francina; Toth, Attila; Martini, Emmanuelle; Livera, Gabriel

    2016-01-01

    Sexual reproduction is crucially dependent on meiosis, a conserved, specialized cell division programme that is essential for the production of haploid gametes. Here we demonstrate that fertility and the implementation of the meiotic programme require a previously uncharacterized meiosis-specific protein, MEIOC. Meioc invalidation in mice induces early and pleiotropic meiotic defects in males and females. MEIOC prevents meiotic transcript degradation and interacts with an RNA helicase that binds numerous meiotic mRNAs. Our results indicate that proper engagement into meiosis necessitates the specific stabilization of meiotic transcripts, a previously little-appreciated feature in mammals. Remarkably, the upregulation of MEIOC at the onset of meiosis does not require retinoic acid and STRA8 signalling. Thus, we propose that the complete induction of the meiotic programme requires both retinoic acid-dependent and -independent mechanisms. The latter process involving post-transcriptional regulation likely represents an ancestral mechanism, given that MEIOC homologues are conserved throughout multicellular animals. PMID:26742488

  17. Meiosis.

    ERIC Educational Resources Information Center

    Henderson, Paula

    This autoinstructional lesson deals with the study of cytology (or cells) with emphasis placed on cell reproduction. Knowledge of the structure of the DNA molecule and of the stages of mitotic cell division are considered prerequisites for this lesson. Approximately 15 minutes is the established time set for the activity. The behavioral objectives…

  18. Ectopic Centromere Nucleation by CENP-A in Fission Yeast

    PubMed Central

    Gonzalez, Marlyn; He, Haijin; Dong, Qianhua; Sun, Siyu; Li, Fei

    2014-01-01

    The centromere is a specific chromosomal locus that organizes the assembly of the kinetochore. It plays a fundamental role in accurate chromosome segregation. In most eukaryotic organisms, each chromosome contains a single centromere the position and function of which are epigenetically specified. Occasionally, centromeres form at ectopic loci, which can be detrimental to the cell. However, the mechanisms that protect the cell against ectopic centromeres (neocentromeres) remain poorly understood. Centromere protein-A (CENP-A), a centromere-specific histone 3 (H3) variant, is found in all centromeres and is indispensable for centromere function. Here we report that the overexpression of CENP-ACnp1 in fission yeast results in the assembly of CENP-ACnp1 at noncentromeric chromatin during mitosis and meiosis. The noncentromeric CENP-A preferentially assembles near heterochromatin and is capable of recruiting kinetochore components. Consistent with this, cells overexpressing CENP-ACnp1 exhibit severe chromosome missegregation and spindle microtubule disorganization. In addition, pulse induction of CENP-ACnp1 overexpression reveals that ectopic CENP-A chromatin can persist for multiple generations. Intriguingly, ectopic assembly of CENP-Acnp1 is suppressed by overexpression of histone H3 or H4. Finally, we demonstrate that deletion of the N-terminal domain of CENP-Acnp1 results in an increase in the number of ectopic CENP-A sites and provide evidence that the N-terminal domain of CENP-A prevents CENP-A assembly at ectopic loci via the ubiquitin-dependent proteolysis. These studies expand our current understanding of how noncentromeric chromatin is protected from mistakenly assembling CENP-A. PMID:25298518

  19. Ectopic centromere nucleation by CENP--a in fission yeast.

    PubMed

    Gonzalez, Marlyn; He, Haijin; Dong, Qianhua; Sun, Siyu; Li, Fei

    2014-12-01

    The centromere is a specific chromosomal locus that organizes the assembly of the kinetochore. It plays a fundamental role in accurate chromosome segregation. In most eukaryotic organisms, each chromosome contains a single centromere the position and function of which are epigenetically specified. Occasionally, centromeres form at ectopic loci, which can be detrimental to the cell. However, the mechanisms that protect the cell against ectopic centromeres (neocentromeres) remain poorly understood. Centromere protein-A (CENP-A), a centromere-specific histone 3 (H3) variant, is found in all centromeres and is indispensable for centromere function. Here we report that the overexpression of CENP-A(Cnp1) in fission yeast results in the assembly of CENP-A(Cnp1) at noncentromeric chromatin during mitosis and meiosis. The noncentromeric CENP-A preferentially assembles near heterochromatin and is capable of recruiting kinetochore components. Consistent with this, cells overexpressing CENP-A(Cnp1) exhibit severe chromosome missegregation and spindle microtubule disorganization. In addition, pulse induction of CENP-A(Cnp1) overexpression reveals that ectopic CENP-A chromatin can persist for multiple generations. Intriguingly, ectopic assembly of CENP-A(cnp1) is suppressed by overexpression of histone H3 or H4. Finally, we demonstrate that deletion of the N-terminal domain of CENP-A(cnp1) results in an increase in the number of ectopic CENP-A sites and provide evidence that the N-terminal domain of CENP-A prevents CENP-A assembly at ectopic loci via the ubiquitin-dependent proteolysis. These studies expand our current understanding of how noncentromeric chromatin is protected from mistakenly assembling CENP-A. PMID:25298518

  20. Primary ectopic frontotemporal craniopharyngioma

    PubMed Central

    Ortega-Porcayo, Luis Alberto; Ponce-Gómez, Juan Antonio; Martínez-Moreno, Mauricio; Portocarrero-Ortíz, Lesly; Tena-Suck, Martha Lilia; Gómez-Amador, Juan Luis

    2015-01-01

    Introduction Primary ectopic craniopharyngiomas have only rarely been reported. Craniopharyngiomas involve usually the sellar and suprasellar region, but can be originated from cell remnants of the obliterated craniopharyngeal duct or metaplastic change of andenohypophyseal cells. We present the first case of a primary ectopic frontotemporal craniopharyngioma. Presentation of case A 35-year old woman presented with a one-year history of headache and diplopia. MRI showed a large frontotemporal cystic lesion. Tumor resection was performed with a keyhole endoscopic frontal lateral approach. The pathological features showed an adamantinomatous craniopharyngioma with a cholesterol granuloma reaction. Discussion There have been reported different localizations for primary ectopic craniopharyngioma. Our case presented a lobulated frontotemporal cystic mass formed by a dense eosinophilic proteinaceous material dystrophic calcifications and cholesterol crystals, with epithelial remnants. No tumor regrowth was observed in the magnetic resonance image 27 months postoperatively. Conclusion Primary ectopic craniopharyngioma is a rare entity with a pathogenesis that remains uncertain. This is an unusual anatomic location associated with unique clinical findings. PMID:25725331

  1. Prevalence of cytomegalovirus, and its effect on the expression of inducible and endothelial nitric oxide synthases in Fallopian tubes collected from women with and without ectopic pregnancy.

    PubMed

    Batwa, S A; Ashshi, A M; Kamfar, F F; Ahmad, J; Idris, S; Khojah, A; Al-Qadi, N M; Refaat, B

    2016-01-01

    To measure the prevalence of cytomegalovirus (CMV) infection in ectopic pregnancy (EP) and its effect on the expression of inducible and endothelial nitric oxide synthases (iNOS, eNOS) by Fallopian tubes (FT) bearing an EP. This was a prospective case-control study. Blood and tubal samples were collected from 84 Eps and 51 controls (20 total abdominal hysterectomy (TAH) during the luteal phase and another 31 tubal ligations). CMV IgM and IgG antibodies were measured by ELISA, and an IVD CE PCR kit was used to detect CMV in the FTs. iNOS and eNOS were measured by immunohistochemistry and quantitative RT-PCR in FTs obtained from CMV-positive EP (n = 12), and the results were compared with those obtained from CMV-negative EP (n = 11) and TAH (n = 8). The frequencies of CMV IgM (51.2 % vs 17.6 %), IgG (77.4 % vs 52.9 %) or both antibodies (41.6 % vs 11.7 %) were significantly higher in EP compared with control. CMV was more common by PCR in FTs from EP (21.4 %) than controls (5.9 %). Twelve women from the PCR positive EP cases (66.6 %) were also simultaneously positive for both CMV IgM & IgG antibodies and had higher expression of eNOS and iNOS at the protein and gene levels compared with negative EP and TAH. Tubal infection with CMV may lead to EP by increasing the production of endothelial and inducible NOS by the FT epithelial cells. Further studies are required to illustrate the role of CMV in the pathogenesis of EP. PMID:26563896

  2. Development of a Meiosis Concept Inventory

    PubMed Central

    Kalas, Pamela; O’Neill, Angie; Pollock, Carol; Birol, Gülnur

    2013-01-01

    We have designed, developed, and validated a 17-question Meiosis Concept Inventory (Meiosis CI) to diagnose student misconceptions on meiosis, which is a fundamental concept in genetics. We targeted large introductory biology and genetics courses and used published methodology for question development, which included the validation of questions by student interviews (n = 28), in-class testing of the questions by students (n = 193), and expert (n = 8) consensus on the correct answers. Our item analysis showed that the questions’ difficulty and discrimination indices were in agreement with published recommended standards and discriminated effectively between high- and low-scoring students. We foresee other institutions using the Meiosis CI as both a diagnostic tool and an instrument to assess teaching effectiveness and student progress, and invite instructors to visit http://q4b.biology.ubc.ca for more information. PMID:24297292

  3. Tradescantia: A Tool for Teaching Meiosis.

    ERIC Educational Resources Information Center

    Hammersmith, Robert L.; Mertens, Thomas R.

    1997-01-01

    Describes a procedure for making slides of microsporogenesis in Tradescantia. Uses photographs to demonstrate that Tradescantia is an ideal organism for studying meiosis in the classroom. Contains 17 references. (JRH)

  4. Ectopic expression of H2AX protein promotes TrkA-induced cell death via modulation of TrkA tyrosine-490 phosphorylation and JNK activity upon DNA damage

    SciTech Connect

    Jung, Eun Joo; Kim, Deok Ryong

    2011-01-21

    Research highlights: {yields} We established TrkA-inducible U2OS cells stably expressing GFP-H2AX proteins. {yields} GFP-H2AX was colocalized with TrkA in the cytoplasm. {yields} {gamma}H2AX production was significantly increased upon activation of TrkA and suppressed by TrkA inhibitor or JNK inhibitor. {yields} Ectopic expression of H2AX promoted TrkA-mediated cell death through the modulation of TrkA tyrosine-490 phosphorylation and JNK activity upon DNA damage. -- Abstract: We previously reported that TrkA overexpression causes accumulation of {gamma}H2AX proteins in the cytoplasm, subsequently leading to massive cell death in U2OS cells. To further investigate how cytoplasmic H2AX is associated with TrkA-induced cell death, we established TrkA-inducible cells stably expressing GFP-tagged H2AX. We found that TrkA co-localizes with ectopically expressed GFP-H2AX proteins in the cytoplasm, especially at the juxta-nuclear membranes, which supports our previous results about a functional connection between TrkA and {gamma}H2AX in TrkA-induced cell death. {gamma}H2AX production from GFP-H2AX proteins was significantly increased when TrkA was overexpressed. Moreover, ectopic expression of H2AX activated TrkA-mediated signal pathways via up-regulation of TrkA tyrosine-490 phosphorylation. In addition, suppression of TrkA tyrosine-490 phosphorylation under a certain condition was removed by ectopic expression of H2AX, indicating a functional role of H2AX in the maintenance of TrkA activity. Indeed, TrkA-induced cell death was highly elevated by ectopic H2AX expression, and it was further accelerated by DNA damage via JNK activation. These all results suggest that cytoplasmic H2AX could play an important role in TrkA-mediated cell death by modulating TrkA upon DNA damage.

  5. Ectopic expression of a conifer Abscisic Acid Insensitive3 transcription factor induces high-level synthesis of recombinant human alpha-L-iduronidase in transgenic tobacco leaves.

    PubMed

    Kermode, Allison R; Zeng, Ying; Hu, Xiaoke; Lauson, Samantha; Abrams, Suzanne R; He, Xu

    2007-04-01

    We are examining various plant-based systems to produce enzymes for the treatment of human lysosomal storage disorders. Constitutive expression of the gene encoding the human lysosomal enzyme, alpha-L-iduronidase (IDUA; EC 3.2.1.76) in leaves of transgenic tobacco plants resulted in low-enzyme activity, and the protein appeared to be subject to proteolysis. Toward enhancing production of this recombinant enzyme in vegetative tissues, transgenic tobacco plants were generated to co-express a CaMV35S:Chamaecyparis nootkatensis Abscisic Acid Insensitive3 (CnABI3) gene construct, along with the human gene construct. The latter contained regulatory sequences of the Phaseolus vulgaris arcelin 5-I gene (5'-flanking, signal-peptide-encoding, and 3'-flanking regions). Ectopic synthesis of the CnABI3 protein led to the transactivation of the arcelin promoter and accordingly high activity (e.g., 25,000 pmol/min/mg total soluble protein) and levels of recombinant IDUA mRNA and protein were induced in leaves of transgenic tobacco, particularly in the presence of 150-200 microM S-(+)-ABA. Synthesis of human IDUA containing a carboxy-terminal ER retention (SEKDEL) sequence was also inducible by ABA in leaves co-transformed with the CnABI3 gene. As compared to the natural S-(+)-ABA, two persistent ABA analogues, (+)-8' acetylene ABA and (+)-8'methylene ABA, led to greater levels of beta-glucuronidase (GUS) reporter activities in leaves co-expressing the CnABI3 gene and a vicilin:GUS chimeric gene. In contrast, (+)-8' acetylene ABA and natural ABA appeared to be equally effective in stimulating the CnABI3-induced expression of an arcelin:GUS gene, and of the human IDUA gene, the latter also driven by arcelin-gene-regulatory sequences. Various stress-related treatments, particularly high concentrations of NaCl, had an even greater effect than ABA in promoting accumulation of human IDUA in co-transformed tobacco leaves. This strategy provides the means of enhancing the yields of

  6. Cholesteatoma in ectopic kidney

    PubMed Central

    Karabulut, Yasemin Yuyucu; Tek, Mesut; Eti, Neslihan; Akbay, Erdem

    2016-01-01

    Cholesteatoma in the urinary system is a rarely seen benign condition. Rosina firstly defined this condition in the year 1953. Histopathologically it is characterized with keratinization, and squamous metaplasia of urothelial epithelium associated with desquamation of keratinized layers. Flank pain is the most common symptom that is caused by elimination of keratinous material. In our case we will discuss cholesteatoma developed in an ectopic kidney which has not been described in the literature before.

  7. Ectopic intracranial germinoma.

    PubMed

    Shankar, Samantha; Wu, Xiao; Kalra, Vivek B; Huttner, Anita J; Malhotra, Ajay

    2016-09-01

    Intracranial ectopic germinomas are often associated with synchronous midline disease. Germinomas involving the corpus callosum are exceedingly rare. The reported imaging appearance is not as varied as one might expect and a review of the literature reveals a few common imaging features amongst most ectopic lesions, including cyst formation. We report a 24-year-old man with panhypopituitarism. Neuroimaging revealed three enhancing lesions involving the pituitary infundibulum, the pineal region, and a parenchymal lesion involving the genu of the corpus callosum. The described ectopic mass, a parenchymal lesion, was associated with small peripheral cysts. Stereotactic biopsy and histopathological evaluation revealed this mass to be a germinoma. Following chemotherapy and radiation therapy, there was near-total resolution of the intracranial disease. Preoperative imaging plays an important role, not only in delineating the extent of disease, but also in assisting in generating an appropriate differential diagnosis. Germinomas in the corpus callosum are exceedingly rare but should be considered in the differential of any young patient with a characteristic cystic and solid intra-axial mass. PMID:27050919

  8. Stable Ectopic Expression of ST6GALNAC5 Induces Autocrine MET Activation and Anchorage-Independence in MDCK Cells

    PubMed Central

    Chu, Chia; Bottaro, Donald P.; Betenbaugh, Michael J.; Shiloach, Joseph

    2016-01-01

    The epithelial-mesenchymal transition (EMT) is a complex cancer progression that can boost the metastatic potential of transformed cells by inducing migration, loss of cell adhesion, and promoting proliferation under anchorage-independent conditions. A DNA microarray analysis was performed comparing parental anchorage-dependent MDCK cells and anchorage-independent MDCK cells that were engineered to express human siat7e (ST6GALNAC5). The comparison identified several genes involved in the EMT process that were differentially expressed between the anchorage-dependent and the anchorage-independent MDCK cell lines. The hepatocyte growth factor gene (hgf) was found to be over-expressed in the engineered MDCK-siat7e cells at both transcription and protein expression levels. Phosphorylation analysis of the MET receptor tyrosine kinase confirmed the activation of an autocrine loop of the HGF/ MET signaling pathway in the MDCK-siat7e cells. When MET activities were suppressed by using the small-molecular inhibitor drug PF-02341066 (Crizotinib), the anchorage-independent MDCK-siat7e cells reverted to the cellular morphology of the parental anchorage-dependent MDCK cells. These observations indicate that the MET receptor plays a central role in the growth properties of the MDCK cells and its phosphorylation status is likely dependent on sialylation. Further investigation of the downstream signaling targets in the MET network showed that the degree of MDCK cell adhesion correlated with secretion levels of a matrix metalloproteinase, MMP1, suggesting a role of metalloproteinases in the EMT process. These results demonstrate that in addition to its application in biotechnology processes, MDCK-siat7e may serve as a model cell for metastasis studies to decipher the sequence of events leading up to the activation of EMT. PMID:26848584

  9. The oxidative damage initiation hypothesis for meiosis.

    PubMed

    Hörandl, Elvira; Hadacek, Franz

    2013-12-01

    The maintenance of sexual reproduction in eukaryotes is still a major enigma in evolutionary biology. Meiosis represents the only common feature of sex in all eukaryotic kingdoms, and thus, we regard it a key issue for discussing its function. Almost all asexuality modes maintain meiosis either in a modified form or as an alternative pathway, and facultatively apomictic plants increase frequencies of sexuality relative to apomixis after abiotic stress. On the physiological level, abiotic stress causes oxidative stress. We hypothesize that repair of oxidative damage on nuclear DNA could be a major driving force in the evolution of meiosis. We present a hypothetical model for the possible redox chemistry that underlies the binding of the meiosis-specific protein Spo11 to DNA. During prophase of meiosis I, oxidized sites at the DNA molecule are being targeted by the catalytic tyrosine moieties of Spo11 protein, which acts like an antioxidant reducing the oxidized target. The oxidized tyrosine residues, tyrosyl radicals, attack the phosphodiester bonds of the DNA backbone causing DNA double strand breaks that can be repaired by various mechanisms. Polyploidy in apomictic plants could mitigate oxidative DNA damage and decrease Spo11 activation. Our hypothesis may contribute to explaining various enigmatic phenomena: first, DSB formation outnumbers crossovers and, thus, effective recombination events by far because the target of meiosis may be the removal of oxidative lesions; second, it offers an argument for why expression of sexuality is responsive to stress in many eukaryotes; and third, repair of oxidative DNA damage turns meiosis into an essential characteristic of eukaryotic reproduction. PMID:23995700

  10. Reduced fertility and inability of oocytes to resume meiosis in mice deficient of the Lxr genes.

    PubMed

    Steffensen, Knut R; Robertson, Kirsten; Gustafsson, Jan-Ake; Andersen, Claus Yding

    2006-08-15

    Cholesterol precursors act as activators of the nuclear hormone receptor, liver X receptor (LXR). One of these LXR-activating ligands is meiosis activating sterol (MAS), which also induces resumption of meiosis in oocytes from mice in vitro. Whether LXR participates in the regulation of oocyte maturation and whether the expression of either one of the two paralogues of LXR (alpha and beta) affect fertility of mice has, however, not yet been clarified. Female mice lacking Lxra, Lxrb or both genes (Lxra(-/-), Lxrb(-/-) and Lxrab(-/-), respectively) conceive less frequently and have significantly fewer pups per litter as compared to wild type mice. Both Lxra and Lxrb mRNA were found to be expressed in mouse oocytes. The relative expression of, in particular, Lxrb was almost two orders of magnitude higher than in liver, brain and testis. A water-soluble LXR agonist caused naked oocytes, but not cumulus enclosed oocytes (CEO), from wild type mice to resume meiosis significantly more often than control oocytes. Follicle stimulating hormone (FSH) is a potent stimulator of meiosis in CEO from wild type mice, but was without effect in mice lacking both Lxr genes. Zymosterol, a MAS active substance, induced resumption of meiosis in oocytes from Lxrab(-/-) mice, but significantly less effectively than in oocytes from wild type mice. Taken together, LXRs seem to affect ovarian function, suggesting specific roles of cholesterol precursors in regulation of female reproduction. PMID:16895745

  11. DLH1 is a functional Candida albicans homologue of the meiosis-specific gene DMC1

    SciTech Connect

    Diener, A.C.; Fink, G.R.

    1996-06-01

    DMC1/LIM15 homologue 1 (DLH1), a gene related to meiosis-specific genes, has been isolated from Candida albicans, a fungus thought not to undergo meiosis. The deduced protein sequence of DLH1 contains 74% amino acid identity with Dmc1p from Saccharomyces cerevisiae and 63% with Lim15p from the plant Lilium longiflorum, meiosis-specific homologous of Escherichia coli RecA. Candida DLH1 complements a dmc1/dmc1 null mutant in S. cerevisiae. High copy expression of DLH1 restores both sporulation and meiotic recombination to a Saccharomyces dmc1/{Delta}/dmc1{Delta} strain. Unlike the DMC1 gene, which is transcribed only in meiotic cells, the heterologous Candida DLH1 gene is transcribed in both vegetative and meiotic cells of S. cerevisiae. Transcription of DLH1 is not detected or induced in C. albicans under conditions that induce DMC1 and meiosis in S. cerevisiae. The presence of an intact homologue of a meiosis-specific gene in C. albicans raises the possibility that this organism has a cryptic meiotic pathway. 25 refs., 6 figs., 3 tabs.

  12. Paradoxical widespread c-Fos expression induced by a GABA agonist in the forebrain of transgenic mice with ectopic expression of the GABA(A) α6 subunit.

    PubMed

    Hellsten, K S; Linden, A-M; Korpi, E R

    2015-05-01

    A GABA-site agonist gaboxadol (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) at 3 mg/kg induces strong anxiolytic response in a transgenic Thy1α6 mouse line ectopically expressing the GABA(A) receptor α6 subunit gene under the Thy-1.2 promoter. Now, we compared brain activation patterns between Thy1α6 and wild-type mice to identify brain structures potentially mediating this anxiolytic response. Acutely efficient anxiolytics such as benzodiazepines typically depress most brain regions while activating specifically neurons within the central extended amygdala. Gaboxadol treatment (3 mg/kg, i.p., 2 h) induced a significant increase in c-Fos expression selectively in many Thy1α6 brain regions including the limbic cortex, anterior olfactory nucleus, septal area and central and basolateral nuclei of amygdala. It failed to activate the lateral part of mediodorsal thalamic nucleus (MDL) in the Thy1α6 mice that was activated in the wild-type mice. Detailed mapping of the α6 subunit mRNA by in situ hybridization revealed expression in the middle layers of the isocortex, olfactory areas, hippocampal formation and basolateral nucleus of amygdala (BLA) in the Thy1α6 forebrain. The ligand autoradiographies (t-butylbicyclophosphoro[(35)S]thionate ([(35)S]TBPS) and [(3)H]Ro 15-4513) revealed high levels of pharmacologically active extrasynaptic α6β and α6βγ2 GABA(A) receptors in these same areas. However, c-Fos induction by gaboxadol treatment in Thy1α6 brain was not restricted to areas highly expressing the α6-containing GABA(A) receptors suggesting that indirect pathways lead to the paradoxically widespread activation. Interestingly, the activation pattern by gaboxadol at the dose that is anxiolytic in Thy1α6 mice resembled closely that observed after various fear- and stress-provoking challenges. However, our results are consistent with a recent observation that optogenetic activation of specific neuronal pathways in the extended amygdala mediates anxiolytic

  13. Role of the planar cell polarity pathway in regulating ectopic hair cell-like cells induced by Math1 and testosterone treatment.

    PubMed

    Yang, Xiao-Yu; Jin, Kai; Ma, Rui; Yang, Juan-Mei; Luo, Wen-Wei; Han, Zhao; Cong, Ning; Ren, Dong-Dong; Chi, Fang-Lu

    2015-07-30

    Planar cell polarity (PCP) signaling regulates cochlear extension and coordinates orientation of sensory hair cells in the inner ear. Retroviral-mediated introduction of the Math1 transcription factor leads to the transdifferentiation of some mature supporting cells into hair cells. Testosterone, a gonadal sex steroid hormone, is associated with neuroprotection and regeneration in Central Nervous System (CNS) development. Experiments were performed in vitro using Ad5-EGFP-Math1/Ad5-Math1 in neonatal mouse cochleas. Establishment of ectopic hair-cell like cell(HCLC) polarity in the lesser epithelial ridge (LER) with or without testosterone-3-(O-carboxymethyl) oxime bovine serum albumin (testosterone-BSA) treatment was investigated to determine the role of the PCP pathway in regulating ectopic regenerated (HCLCs) through induction by Math1 and testosterone treatment. After Math1 infection, new ectopic regenerated HCLCs were detected in the LER. After the HCLCs developed actin-rich stereocilia, the basal bodies moved from the center to the distal side. Moreover, the narrower, non-sensory LER region meant that the convergent extension (CE) was also established after transfection with Math1. After 9 days of in vitro testosterone-BSA treatment, more Edu(+), Sox2(+), and HCLC cells were observed in the LER with an accompanying downregulation of E-cadherin. Interestingly, the CE of the Ad5-EGFP-math1 treated LER is altered, but the intrinsic cellular polarity of the HCLCs is not obviously changed. In summary, our results indicate that PCP signaling is involved in the development of ectopic HCLCs and the CE of the ectopic sensory region is altered by testosterone-BSA through downregulation of cell-cell adhesion. Testosterone-BSA and Math1 treatment could promote an increase in HCLCs in the LER through proliferation and transdifferentiation. PMID:25957791

  14. An Ectopic Pelvic Kidney

    PubMed Central

    Bhoil, Rohit; Sood, Dinesh; Singh, Yash Paul; Nimkar, Kshama; Shukla, Anurag

    2015-01-01

    Summary Background If a kidney does not ascend as it should in normal fetal development, it remains in the pelvic area and is called a pelvic kidney. Often a person with a pelvic kidney will go through his/her whole life unaware of this condition, unless it is discovered during neonatal kidney ultrasound screening or if complications arise later in life due to this or a completely different reason and the condition is noted during investigations. Generally, this is not a harmful condition but it can lead to complications like in our case. With appropriate testing and treatment, if needed, an ectopic kidney should cause no serious long-term health complications and all that may be required for the patient is reassurance with advice to follow up at regular intervals. Case Report A 28-year-old male presented with recurrent pain in his lower left abdomen for one month and an episode of hematuria 3 days earlier accompanied by an attack of acute pain lasting for 3–4 hours. He gave a history of passing 2 small (about 5 mm each) calculi in his urine after the occurrence of hematuria, following which pain decreased in intensity. No history of fever was present. Conclusions Although a simple ectopic kidney seldom causes symptoms, the association of malrotation of the renal pelvis with calculus increases the risk of hematuria and/or hydronephrosis, presenting with colicky pain as in the present case. The clinician should be aware of these in such a case. If asymptomatic, no treatment is required. However, the patient should be advised to have follow-up ultrasounds at regular intervals to detect complications like calculus, hydronephrosis, etc. With appropriate testing and treatment, if required, an ectopic kidney should not cause serious long-term health complications. PMID:26413178

  15. Secondary abdominal appendicular ectopic pregnancy.

    PubMed

    Nama, Vivek; Gyampoh, Bright; Karoshi, Mahantesh; McRae, Reynold; Opemuyi, Isaac

    2007-01-01

    Although the case fatality rate for ectopic pregnancies has decreased to 0.08% in industrialized countries, it still represents 3.8% of maternal mortality in the United States alone. In developing countries, the case fatality rate varies from 3% to 27%. Laparoscopic management of tubal pregnancies is now the standard form of treatment where this technology is available. Abdominal pregnancies are rare, and secondary implantation of tubal ectopic pregnancies is the most common cause of abdominal gestations. We present an interesting case of secondary implantation of a tubal ectopic pregnancy to highlight the appendix as a possible secondary implantation site after a tubal ectopic pregnancy. PMID:17630175

  16. Assessing Understanding of Biological Processes: Elucidating Students' Models of Meiosis.

    ERIC Educational Resources Information Center

    Kindfield, Ann C.

    1994-01-01

    Presents a meiosis reasoning problem that provides direct access to students' current models of chromosomes and meiosis. Also included in the article are tips for classroom implementation and a summary of the solution evaluation. (ZWH)

  17. A stubborn anemia caused by ectopic pancreas bleeding in the jejunum revealed by capsule endoscopy

    PubMed Central

    Wang, Qun-Ying; Yang, Xiao-Yun

    2015-01-01

    Ectopic pancreas is extremely rare in clinical setting. Meanwhile, a stubborn anemia without obvious dark bloody stool due to ectopic pancreas diagnosed by capsule endoscopy has not been reported. We reported a case of an ectopic pancreas inducing obscure gastrointestinal bleeding in a 70-year-old woman presenting as stubborn anemia, which was diagnosed by capsule endoscopy. The patient recovered well after resection the lesion. Diagnosis of ectopic pancreas is extremely difficult with conventional techniques. Endoscopists should pay more attention to the ectopic pancreas as a rare differential consideration for occult intestinal bleeding. PMID:26682148

  18. High School Students' Use of Meiosis When Solving Genetics Problems.

    ERIC Educational Resources Information Center

    Wynne, Cynthia F.; Stewart, Jim; Passmore, Cindy

    2001-01-01

    Paints a different picture of students' reasoning with meiosis as they solved complex, computer-generated genetics problems, some of which required them to revise their understanding of meiosis in response to anomalous data. Students were able to develop a rich understanding of meiosis and can utilize that knowledge to solve genetics problems.…

  19. Efficient ectopic gene expression targeting chick mesoderm.

    PubMed

    Oberg, Kerby C; Pira, Charmaine U; Revelli, Jean-Pierre; Ratz, Beate; Aguilar-Cordova, Estuardo; Eichele, Gregor

    2002-07-01

    The chick model has been instrumental in illuminating genes that regulate early vertebrate development and pattern formation. Targeted ectopic gene expression is critical to dissect further the complicated gene interactions that are involved. In an effort to develop a consistent method to ectopically introduce and focally express genes in chick mesoderm, we evaluated and optimized several gene delivery methods, including implantation of 293 cells laden with viral vectors, direct adenoviral injection, and electroporation (EP). We targeted the mesoderm of chick wing buds between stages 19 and 21 (Hamburger and Hamilton stages) and used beta-galactosidase and green fluorescent protein (GFP) to document gene transfer. Expression constructs using the cytomegalovirus (CMV) promoter, the beta-actin promoter, and vectors with an internal ribosomal entry sequence linked to GFP (IRES-GFP) were also compared. After gene transfer, we monitored expression for up to 3 days. The functionality of ectopic expression was demonstrated with constructs containing the coding sequences for Shh, a secreted signaling protein, or Hoxb-8, a transcription factor, both of which can induce digit duplication when ectopically expressed in anterior limb mesoderm. We identified several factors that enhance mesodermal gene transfer. First, the use of a vector with the beta-actin promoter coupled to the 69% fragment of the bovine papilloma virus yielded superior mesodermal expression both by markers and functional results when compared with several CMV-driven vectors. Second, we found the use of mineral oil to be an important adjuvant for EP and direct viral injection to localize and contain vector within the mesoderm at the injection site. Lastly, although ectopic expression could be achieved with all three methods, we favored EP confined to the mesoderm with insulated microelectrodes (confined microelectroporation- CMEP), because vector construction is rapid, the method is efficient, and results

  20. Primary ectopic frontotemporal extradural craniopharyngioma

    PubMed Central

    Pourkhalili, Reza; Shekarchizadeh, Ahmad; Seif, Bahram

    2016-01-01

    We present a case of primary ectopic frontotemporal extradural craniopharyngioma. Primary ectopic craniopharyngiomas are very rare and have been reported involving the fourth ventricle, infrasellar region, lateral ventricle, temporal area, cerebellopontine angle, clivus, corpus callosum, and prepontine cistern. There was just 1 case of craniopharyngioma previously presented in the literature, with nearly same location as the presenting case. PMID:27195250

  1. Follow-up study on histogenesis of microcephaly associated with ectopic gray matter induced by prenatal {gamma}-irradiation in the mouse

    SciTech Connect

    Sun, Xue-Zhi; Inouye, Monoru; Takagishi, Yoshiko

    1996-03-01

    Brain malformation with ectopic gray matter was visualized with magnetic resonance imaging in small-sized heads of prenatally exposed atomic bomb survivors. The identical brain malformation was reproduced in mice and its histogenesis was studied in the present experiment. Pregnant mice were exposed to {sup 60}Co {gamma}-irradiation at a single dose of 1.5 Gy on embryonic day 13 (E13), and then injected intraperitoneally with 30 mg/kg BrdU on E15. The extensive dead cells appeared throughout the brain mantle at 6 hours (h) after exposure. On E16 cell aggregations formed rosettes. On E18 a high proportion of BrdU-labeled cells reached the superficial layers of the cortical plate with the remaining cells located in the ectopic neuronal masses. The quantitative study showed that labeled cells in layers II to III were fewer and those in layers IV to VI more numerous in the prenatally irradiated adult mice than in controls. The anti-GFAP immunostaining revealed that the glial fibers in the irradiated mice were preserved, but disorganized. These findings suggested that the majority of migrating neurons were able to arrive at their normal layers, but some neurons remained due to the interrupted migratory pathway and eventually formed ectopic neuronal masses beneath the subcortical white matter. 60 refs., 5 figs., 1 tab.

  2. A Molecular Portrait of Arabidopsis Meiosis

    PubMed Central

    Ma, Hong

    2006-01-01

    Meiosis is essential for eukaryotic sexual reproduction and important for genetic diversity among individuals. Efforts during the last decade in Arabidopsis have greatly expanded our understanding of the molecular basis of plant meiosis, which has traditionally provided much information about the cytological description of meiosis. Through both forward genetic analysis of mutants with reduced fertility and reverse genetic studies of homologs of known meiotic genes, we now have a basic knowledge about genes important for meiotic recombination and its relationship to pairing and synapsis, critical processes that ensure proper homolog segregation. In addition, several genes affecting meiotic progression, spindle assembly, chromosome separation, and meiotic cytokinesis have also been uncovered and characterized. It is worth noting that Arabidopsis molecular genetic studies are also revealing secrets of meiosis that have not yet been recognized elsewhere among eukaryotes, including gene functions that might be unique to plants and those that are potentially shared with animals and fungi. As we enter the post-genomics era of plant biology, there is no doubt that the next ten years will see an even greater number of discoveries in this important area of plant development and cell biology. Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; DSB, double strand break; DSBR, double strand break repair; SC, synaptonemal complex; TEM, transmission electron microscopy PMID:22303228

  3. Cytological Analysis of Meiosis in Caenorhabditis elegans

    PubMed Central

    Phillips, Carolyn M.; McDonald, Kent L.; Dernburg, Abby F.

    2011-01-01

    The nematode Caenorhabditis elegans has emerged as an informative experimental system for analysis of meiosis, in large part because of the advantageous physical organization of meiotic nuclei as a gradient of stages within the germline. Here we provide tools for detailed observational studies of cells within the worm gonad, including techniques for light and electron microscopy. PMID:19685325

  4. The transcriptome landscape of early maize meiosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meiosis, particularly meiotic recombination, is a major factor affecting yield and breeding of plants. To gain insight into the transcriptome landscape during early initiation steps of meiotic recombination, we profiled early prophase I meiocytes from maize using RNA-seq. Our analyses of genes prefe...

  5. Meiosis-Driven Genome Variation in Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meiosis includes two successive divisions of the nucleus with one round of DNA replication and leads to the formation of gametes with half the chromosomes of the mother cell during sexual reproduction. It provides a cytological basis for gametogenesis and inheritance in eukaryotes. Meiotic cell di...

  6. Possible Role of Aurora-C in Meiosis

    PubMed Central

    Yang, Kuo-Tai; Tang, Chieh-Ju C.; Tang, Tang K.

    2015-01-01

    The meiotic generation of haploid gametes with equal contents of genetic material is important for sexual reproduction in mammals. Errors in the transmission of chromosomes during meiosis may lead to aneuploidy, which is the leading cause of miscarriage and congenital birth defects in humans. The Aurora kinases, which include Aurora-A, Aurora-B, and Aurora-C, are highly conserved serine–threonine kinases that play essential roles in centrosome function, chromosome segregation, and cytokinesis during mitosis and meiosis. While Aurora-A and Aurora-B have been extensively studied in mitosis, the role of Aurora-C in meiosis is only now starting to be revealed. For example, the perturbation of Aurora-C kinase activity by microinjection of Aurora-C-kinase-dead mutant mRNAs into mouse oocytes induced multiple defects, including chromosome misalignment, abnormal kinetochore–microtubule attachment, premature chromosome segregation, and failure of cytokinesis during meiotic division. However, the analysis of such defects is complicated by the possibility that Aurora-B may be present in mammalian germ cells. Interestingly, a homozygous mutation of Aurora-C in humans leads to the production of large-headed polyploid spermatozoa and causes male infertility, but homozygous females are fertile. Mouse studies regarding the roles of Aurora-B and Aurora-C in female meiotic divisions have yielded inconsistent results, and it has proven difficult to explain why homozygous human females have no significant clinical phenotype. In this review, we will discuss the controversial status of Aurora-B in oocytes and the possible role of Aurora-C during meiotic division. PMID:26322271

  7. Cervical ectopic pregnancy.

    PubMed

    Samal, Sunil Kumar; Rathod, Setu

    2015-01-01

    Cervical pregnancy is a rare type of ectopic pregnancy and it represents <1% of all ectopic pregnancies. Early diagnosis and medical management with systemic or local administration of methotrexate is the treatment of choice. If the pregnancy is disturbed, it may lead to massive hemorrhage, which may require hysterectomy to save the patient. We report three cases of cervical pregnancy managed successfully with different approaches of management. Our first case, 28 years old G3P2L2 with previous two lower segment cesarean sections, presented with bleeding per vaginum following 6 weeks of amenorrhea. Clinical examination followed by transvaginal ultrasound confirmed the diagnosis of cervical pregnancy. Total abdominal hysterectomy was done in view of intractable bleeding to save the patient. The second case, a 26-year-old second gravida with previous normal vaginal delivery presented with pain abdomen and single episode of spotting per vaginum following 7 weeks of amenorrhea. Transvaginal ultrasound revealed empty endometrial cavity, closed internal os with gestational sac containing live fetus of 7 weeks gestational age in cervical canal and she was treated with intra-amniotic potassium chloride followed by systemic methotrexate. Follow up with serum beta human chorionic gonadotropin level revealed successful outcome. Our third case, a 27-year-old primigravida with history of infertility treatment admitted with complaints of bleeding per vaginum for 1 day following 8 weeks amenorrhea. She was diagnosed as cervical pregnancy by clinical examination, confirmed by transvaginal ultrasonography and subsequently managed by dilation and curettage with intracervical Foleys' ballon tamponade. PMID:25810679

  8. Overnutrition, ectopic lipid and the metabolic syndrome.

    PubMed

    Grundy, Scott M

    2016-08-01

    The metabolic syndrome is a constellation of metabolic risk factors including atherogenic dyslipidemia (elevated serum triglycerides, reduced high-density lipoprotein (HDL) cholesterol), elevated blood pressure, dysglycemia (insulin resistance and elevated serum glucose), a pro-inflammatory state, and a prothrombotic state. Most persons with metabolic syndrome are obese, and usually have abdominal obesity. Generally, obesity is a reflection of overnutrition. A current view is that when adipose tissue fails to store all excess nutrients as triglyceride, lipid begins to accumulate in various tissues (eg, muscle, liver, pancreas, and heart). This accumulation is called ectopic lipid. Various mechanisms have been proposed whereby ectopic lipid is detrimental in different tissues; these derangements induce metabolic risk factors. The foundation of the metabolic syndrome thus appears to be overnutrition, that is, more nutrient intake than can be safely disposed by lipid oxidation. Excess dietary carbohydrate also induces ectopic lipid. Of interest, less than half of obese individuals develop metabolic syndrome. Through various mechanisms they adapt to overnutrition so as to minimize lipid overload in tissues, and consequently, prevent the syndrome. PMID:27194746

  9. Sonography of Methotrexate for Ectopics

    NASA Astrophysics Data System (ADS)

    Urzicǎ, Denise; Dorohoi, Dana-Ortansa

    2007-04-01

    Treatment unruptured ectopic pregnancy with methotrexate (MTX) and citrovorum factor is now an established alternative to surgical therapy. Serial measurements of serum beta-HCG and early ultrasound examination have allowed detection of early and unruptured tubal ectopic pregnancies, permitting treatment without removal of the tube. It is believed that preserving the tube increases the chance of subsequent live births. Our findings suggest that outpatient transvaginal intratubal methorexate administration can provide a safe and effective alternative to surgical treatment for patients with early and unruptured tubal ectopic pregnancy.

  10. Spindle Dynamics during Meiosis in Drosophila Oocytes

    PubMed Central

    Endow, Sharyn A.; Komma, Donald J.

    1997-01-01

    Mature oocytes of Drosophila are arrested in metaphase of meiosis I. Upon activation by ovulation or fertilization, oocytes undergo a series of rapid changes that have not been directly visualized previously. We report here the use of the Nonclaret disjunctional (Ncd) microtubule motor protein fused to the green fluorescent protein (GFP) to monitor changes in the meiotic spindle of live oocytes after activation in vitro. Meiotic spindles of metaphase-arrested oocytes are relatively stable, however, meiotic spindles of in vitro–activated oocytes are highly dynamic: the spindles elongate, rotate around their long axis, and undergo an acute pivoting movement to reorient perpendicular to the oocyte surface. Many oocytes spontaneously complete the meiotic divisions, permitting visualization of progression from meiosis I to II. The movements of the spindle after oocyte activation provide new information about the dynamic changes in the spindle that occur upon re-entry into meiosis and completion of the meiotic divisions. Spindles in live oocytes mutant for a lossof-function ncd allele fused to gfp were also imaged. The genesis of spindle defects in the live mutant oocytes provides new insights into the mechanism of Ncd function in the spindle during the meiotic divisions. PMID:9182665

  11. Mos/mitogen-activated protein kinase can induce early meiotic phenotypes in the absence of maturation-promoting factor: a novel system for analyzing spindle formation during meiosis I.

    PubMed Central

    Choi, T; Rulong, S; Resau, J; Fukasawa, K; Matten, W; Kuriyama, R; Mansour, S; Ahn, N; Vande Woude, G F

    1996-01-01

    Mitogen-activated protein kinase (MAPK) is selectively activated by injecting either mos or MAPK kinase (mek) RNA into immature mouse oocytes maintained in the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). IBMX arrests oocyte maturation, but Mos (or MEK) overexpression overrides this block. Under these conditions, meiosis I is significantly prolonged, and MAPK becomes fully activated in the absence of p34cdc2 kinase or maturation-promoting factor. In these oocytes, large openings form in the germinal vesicle adjacent to condensing chromatin, and microtubule arrays, which stain for both MAPK and centrosomal proteins, nucleate from these regions. Maturation-promoting factor activation occurs later, concomitant with germinal vesicle breakdown, the contraction of the microtubule arrays into a precursor of the spindle, and the redistribution of the centrosomal proteins into the newly forming spindle poles. These studies define important new functions for the Mos/MAPK cascade in mouse oocyte maturation and, under these conditions, reveal novel detail of the early stages of oocyte meiosis I. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8643471

  12. Is there evidence of sexual reproduction (meiosis) in Acanthamoeba?

    PubMed Central

    Khan, Naveed A.; Siddiqui, Ruqaiyyah

    2015-01-01

    Evolution of independently breeding species into males and females (gametes) has remained a puzzle. Given the significant advantages of sexual reproduction over asexual reproduction as a long-term species survival strategy; here, we pose the question whether there is some form of meiosis in Acanthamoeba species, which represents our ancient lineage. The recently available Acanthamoeba genome revealed several genes implicated in meiosis in sexual eukaryotes such as Spo11, Mre11, Rad50, Rad51, Rad52, Mnd1, Dmc1, Msh, and Mlh, suggesting that Acanthamoeba is capable of some form of meiosis, inferring the presence of sexual reproduction in Acanthamoeba, and that meiosis evolved early in eukaryotic evolution. PMID:25800982

  13. Nicotinamide Impairs Entry into and Exit from Meiosis I in Mouse Oocytes

    PubMed Central

    Riepsamen, Angelique; Wu, Lindsay; Lau, Laurin; Listijono, Dave; Ledger, William; Sinclair, David; Homer, Hayden

    2015-01-01

    Following exit from meiosis I, mammalian oocytes immediately enter meiosis II without an intervening interphase, accompanied by rapid reassembly of a bipolar spindle that maintains condensed chromosomes in a metaphase configuration (metaphase II arrest). Here we study the effect of nicotinamide (NAM), a non-competitive pan-sirtuin inhibitor, during meiotic maturation in mouse oocytes. Sirtuins are a family of seven NAD+-dependent deacetylases (Sirt1-7), which are involved in multiple cellular processes and are emerging as important regulators in oocytes and embryos. We found that NAM significantly delayed entry into meiosis I associated with delayed accumulation of the Cdk1 co-activator, cyclin B1. GVBD was also inhibited by the Sirt2-specific inhibitor, AGK2, and in a very similar pattern to NAM, supporting the notion that as in somatic cells, NAM inhibits sirtuins in oocytes. NAM did not affect subsequent spindle assembly, chromosome alignment or the timing of first polar body extrusion (PBE). Unexpectedly, however, in the majority of oocytes with a polar body, chromatin was decondensed and a nuclear structure was present. An identical phenotype was observed when flavopiridol was used to induce Cdk1 inactivation during late meiosis I prior to PBE, but not if Cdk1 was inactivated after PBE when metaphase II arrest was already established, altogether indicating that NAM impaired establishment rather than maintenance of metaphase II arrest. During meiosis I exit in NAM-treated medium, we found that cyclin B1 levels were lower and inhibitory Cdk1 phosphorylation was increased compared with controls. Although activation of the anaphase-promoting complex-Cdc20 (APC-Cdc20) occurred on-time in NAM-treated oocytes, Cdc20 levels were higher in very late meiosis I, pointing to exaggerated APC-Cdc20-mediated proteolysis as a reason for lower cyclin B1 levels. Collectively, therefore, our data indicate that by disrupting Cdk1 regulation, NAM impairs entry into meiosis I and

  14. [Cancer in ectopic breast tissue].

    PubMed

    Røikjer, Johan; Lindmark, Ida; Knudsen, Thor

    2015-06-15

    Two different forms of ectopic breast tissue exist in human beings: supernumerary and aberrant. Both forms are usually seen alongside the milk lines, which extend from the upper limbs to the inguinal region where they give rise to mammary glands, areolas and nipples. Although ectopic- and orthotopic breast tissue are placed in different areas of the body, they still share the same ability to undergo pathological degeneration. The focus of this case report is to shed light on this unusual form of breast cancer, and raise the level of awareness in cases with lumps located in the milk lines. PMID:26101129

  15. Surgical management of ectopic pregnancy.

    PubMed

    Stock, Laura; Milad, Magdy

    2012-06-01

    Surgery remains an acceptable, and sometimes necessary, modality for the treatment of ectopic pregnancy. Laparoscopy is the preferred method of access, yet controversy remains regarding the optimal procedure and postoperative management. Generally, salpingostomy is employed with the goal of maintaining fertility, although data to support this tenet are lacking. In most cases, the decision to perform conservative versus radical surgery is on the basis of the patient's history, her desire for future fertility, and surgical findings. The procedures of salpingostomy and salpingectomy, techniques to prevent and control blood loss at the time of surgery, and surgical options for nontubal ectopic pregnancies are reviewed. PMID:22510627

  16. Heterochronic bilateral ectopic pregnancy after ovulation induction*

    PubMed Central

    Zhu, Bo; Xu, Gu-feng; Liu, Yi-feng; Qu, Fan; Yao, Wei-miao; Zhu, Yi-min; Gao, Hui-juan; Zhang, Dan

    2014-01-01

    Ectopic pregnancy is identified with the widely-applied assisted reproductive technology (ART). Bilateral ectopic pregnancy is a rare form of ectopic pregnancy which is difficult to be diagnosed at the pre-operation stage. In this paper, we presented an unusual case of heterochronic bilateral ectopic pregnancy after stimulated intrauterine insemination (IUI), where there has been a delay of 22 d between the diagnoses of the two ectopic pregnancies. Literature was reviewed on the occurrence of bilateral ectopic pregnancy during the past four years in the MEDLINE database. We found 16 cases of bilateral ectopic pregnancy reported since 2008, and analyzed the characteristics of those cases of bilateral ectopic pregnancy. We emphasize that ovulation induction and other ARTs may increase the risk of bilateral ectopic pregnancy. Because of the difficulty in identification of bilateral ectopic pregnancy by ultrasonography, the clinician should be aware that the treatment of one ectopic pregnancy does not preclude the occurrence of a second ectopic pregnancy in the same patient and should pay attention to the intra-operation inspection of both side fallopian tubes in any ectopic pregnancy case. PMID:25091994

  17. Ectopic expression of an apple apomixis-related gene MhFIE induces co-suppression and results in abnormal vegetative and reproductive development in tomato.

    PubMed

    Liu, Dan-Dan; Dong, Qing-Long; Fang, Mou-Jing; Chen, Ke-Qin; Hao, Yu-Jin

    2012-12-15

    It has been well documented that FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) plays important regulatory roles in diverse developmental processes in model plant Arabidopsis thaliana. However, it is largely unknown how FIE genes function in economically important crops. In this study, MhFIE gene, which was previously isolated from apomictic tea crabapple (Malus hupehensis Redh. var. pingyiensis), was introduced into tomato. The hemizygous transgenic tomato lines produced curly leaves and decreased in seed germination. In addition, the co-suppression of the transgenic MhFIE and endogenous (SlFIE) genes occurred in homozygous transgenic tomatoes. As a result, FIE silencing brought about abnormal phenotypes during reproductive development in tomato, such as increased sepal and petal numbers in flower, a fused ovule and pistil and parthenocarpic fruit formation. A yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) demonstrated that MhFIE interacted with a tomato protein, EZ2 (SlEZ2). Its ectopic expression and SlFIE co-suppression notably influenced the expression of genes associated with leaf, flower, and fruit development. Therefore, together with other PcG proteins, FIE was involved in the regulation of vegetative and reproductive development by modulating the expression of related genes in plants. PMID:23000466

  18. Ectopic miR-125a Expression Induces Long-Term Repopulating Stem Cell Capacity in Mouse and Human Hematopoietic Progenitors.

    PubMed

    Wojtowicz, Edyta E; Lechman, Eric R; Hermans, Karin G; Schoof, Erwin M; Wienholds, Erno; Isserlin, Ruth; van Veelen, Peter A; Broekhuis, Mathilde J C; Janssen, George M C; Trotman-Grant, Aaron; Dobson, Stephanie M; Krivdova, Gabriela; Elzinga, Jantje; Kennedy, James; Gan, Olga I; Sinha, Ankit; Ignatchenko, Vladimir; Kislinger, Thomas; Dethmers-Ausema, Bertien; Weersing, Ellen; Alemdehy, Mir Farshid; de Looper, Hans W J; Bader, Gary D; Ritsema, Martha; Erkeland, Stefan J; Bystrykh, Leonid V; Dick, John E; de Haan, Gerald

    2016-09-01

    Umbilical cord blood (CB) is a convenient and broadly used source of hematopoietic stem cells (HSCs) for allogeneic stem cell transplantation. However, limiting numbers of HSCs remain a major constraint for its clinical application. Although one feasible option would be to expand HSCs to improve therapeutic outcome, available protocols and the molecular mechanisms governing the self-renewal of HSCs are unclear. Here, we show that ectopic expression of a single microRNA (miRNA), miR-125a, in purified murine and human multipotent progenitors (MPPs) resulted in increased self-renewal and robust long-term multi-lineage repopulation in transplanted recipient mice. Using quantitative proteomics and western blot analysis, we identified a restricted set of miR-125a targets involved in conferring long-term repopulating capacity to MPPs in humans and mice. Our findings offer the innovative potential to use MPPs with enhanced self-renewal activity to augment limited sources of HSCs to improve clinical protocols. PMID:27424784

  19. The Retention of Meaningful Understanding of Meiosis and Genetics.

    ERIC Educational Resources Information Center

    Cavallo, Ann Liberatore

    This study investigated the retention of meaningful understanding of the biological topics of meiosis, the Punnett square method and the relations between these two topics. This study also explored the predictive influence of students' general tendency to learn meaningfully or by rote (meaningful learning orientation), prior knowledge of meiosis,…

  20. Complex regulation of sister kinetochore orientation in meiosis-I.

    PubMed

    Bardhan, Amit

    2010-09-01

    Kinetochores mediate chromosome movement during cell division by interacting with the spindle microtubules. Sexual reproduction necessitates the daunting task of reducing ploidy (number of chromosome sets) in the gametes, which depends upon the specialized properties of meiosis. Kinetochores have a central role in the reduction process. In this review, we discuss the complexity of this role of kinetochores in meiosis-I. PMID:20826957

  1. Ectopic Expression of Testis Germ Cell Proteins in Cancer and Its Potential Role in Genomic Instability

    PubMed Central

    Nielsen, Aaraby Yoheswaran; Gjerstorff, Morten Frier

    2016-01-01

    Genomic instability is a hallmark of human cancer and an enabling factor for the genetic alterations that drive cancer development. The processes involved in genomic instability resemble those of meiosis, where genetic material is interchanged between homologous chromosomes. In most types of human cancer, epigenetic changes, including hypomethylation of gene promoters, lead to the ectopic expression of a large number of proteins normally restricted to the germ cells of the testis. Due to the similarities between meiosis and genomic instability, it has been proposed that activation of meiotic programs may drive genomic instability in cancer cells. Some germ cell proteins with ectopic expression in cancer cells indeed seem to promote genomic instability, while others reduce polyploidy and maintain mitotic fidelity. Furthermore, oncogenic germ cell proteins may indirectly contribute to genomic instability through induction of replication stress, similar to classic oncogenes. Thus, current evidence suggests that testis germ cell proteins are implicated in cancer development by regulating genomic instability during tumorigenesis, and these proteins therefore represent promising targets for novel therapeutic strategies. PMID:27275820

  2. Ectopic Expression of Testis Germ Cell Proteins in Cancer and Its Potential Role in Genomic Instability.

    PubMed

    Nielsen, Aaraby Yoheswaran; Gjerstorff, Morten Frier

    2016-01-01

    Genomic instability is a hallmark of human cancer and an enabling factor for the genetic alterations that drive cancer development. The processes involved in genomic instability resemble those of meiosis, where genetic material is interchanged between homologous chromosomes. In most types of human cancer, epigenetic changes, including hypomethylation of gene promoters, lead to the ectopic expression of a large number of proteins normally restricted to the germ cells of the testis. Due to the similarities between meiosis and genomic instability, it has been proposed that activation of meiotic programs may drive genomic instability in cancer cells. Some germ cell proteins with ectopic expression in cancer cells indeed seem to promote genomic instability, while others reduce polyploidy and maintain mitotic fidelity. Furthermore, oncogenic germ cell proteins may indirectly contribute to genomic instability through induction of replication stress, similar to classic oncogenes. Thus, current evidence suggests that testis germ cell proteins are implicated in cancer development by regulating genomic instability during tumorigenesis, and these proteins therefore represent promising targets for novel therapeutic strategies. PMID:27275820

  3. Treatment of ectopic varices with portal hypertension.

    PubMed

    Sato, Takahiro

    2015-06-28

    Ectopic varices are unusual with portal hypertension and can involve any site along the digestive tract outside the gastroesophageal region. Hemorrhage from ectopic varices generally are massive and life threatening. Diagnosis of ectopic varices is difficult and subsequent treatment is also difficult; the optimal treatment has not been established. Recently, interventional radiology and endoscopic treatments have been carried out successfully for hemorrhage from ectopic varices. PMID:26140080

  4. Changes in cGMP levels on meiosis reinitiation of starfish oocytes.

    PubMed

    Nemoto, S; Ishida, K

    1983-04-15

    An intracellular level of cGMP (but not cAMP) transiently decreased the reinitiation of oocyte maturation in the starfish, Asterias amurensis. Exogenously applied cGMP inhibited hormone-induced maturation. Methylxanthines inhibited oocyte maturation by suppressing the decrease in cGMP levels. These results suggest that a decrease in cGMP levels is a prerequisite for meiosis reinitiation of starfish oocytes. PMID:6303819

  5. Ectopic ATP synthase in endothelial cells: a novel cardiovascular therapeutic target.

    PubMed

    Fu, Yi; Zhu, Yi

    2010-01-01

    Adenosine triphosphate (ATP) synthase produces ATP in cells and is found on the inner membrane of mitochondria or the cell plasma membrane (ectopic ATP synthase). Here, we summarize the functions of ectopic ATP synthase in vascular endothelial cells (ECs). Ectopic ATP synthase is involved in adenosine metabolism on the cell surface through its ATP generation or hydrolysis activity. The ATP/ADP generated by the enzyme on the plasma membrane can bind to P2X/P2Y receptors and activate the related signalling pathways to regulate endothelial function. The β-chain of ectopic ATP synthase on the EC surface can recruit inflammatory cells and activate cytotoxic activity to damage ECs and induce vascular inflammation. Angiostatin and other angiogenesis inhibitors can have anti-angiogenic functions by inhibiting ectopic ATP synthase on ECs. Moreover, ectopic ATP synthase on ECs is a receptor for apoA-I, the acceptor of cholesterol efflux, which implies that endothelial ectopic ATP synthase is involved in cholesterol metabolism. Coupling factor 6 (CF6), a part of ectopic ATP synthase, is released from ECs and can inhibit prostacyclin synthesis and promote nitric oxide (NO) degradation to enhance NO bioactivity. Because ATP/ADP generated by ectopic ATP synthase can induce NO production, substances such as CF6 can inhibit NO generation by inhibiting surface ATP/ADP production. Thus, the components of ectopic ATP synthase are associated with regulation of vascular tone. Through these functions, ectopic ATP synthase on ECs is considered a potential and novel therapeutic target for atherosclerosis, hypertension and lipid disorders. PMID:21247400

  6. Stage-Specific Effects of X-Irradiation on Yeast Meiosis

    PubMed Central

    Thorne, L. W.; Byers, B.

    1993-01-01

    Previous work has shown that cdc13 causes meiotic arrest of Saccharomyces cerevisiae following DNA replication by a RAD9-dependent mechanism. In the present work, we have further investigated the implicit effects of chromosomal lesions on progression through meiosis by exposing yeast cells to X-irradiation at various times during sporulation. We find that exposure of RAD9 cells to X-irradiation early in meiosis prevents sporulation, arresting the cells at a stage prior to premeiotic DNA replication. rad9 meiotic cells are much less responsive to X-irradiation damage, completing sporulation after treatment with doses sufficient to cause arrest of RAD9 strains. These findings thereby reveal a RAD9-dependent checkpoint function in meiosis that is distinct from the G(2) arrest previously shown to result from cdc13 dysfunction. Analysis of the spores that continued to be produced by either RAD9 or rad9 cultures that were X-irradiated in later stages of sporulation revealed most spores to be viable, even after exposure to radiation doses sufficient to kill most vegetative cells. This finding demonstrates that the lesions induced by X-irradiation at later times fail to trigger the checkpoint function revealed by cdc13 arrest and suggests that the lesions may be subject to repair by serving as intermediates in the recombination process. Strains mutant for chromosomal synapsis and recombination, and therefore defective in meiotic disjunction, were tested for evidence that X-ray-induced lesions might alleviate inviability by promoting recombination. Enhancement of spore viability when spo11 (but not hop1) diploids were X-irradiated during meiosis indicates that induced lesions may partially substitute for SPO11-dependent functions that are required for the initiation of recombination. PMID:8514137

  7. Stage-specific effects of X-irradiation on Yeast meiosis

    SciTech Connect

    Thorne, L.W.; Byers, B. )

    1993-05-01

    Previous work has shown that cdc 13 causes meiotic arrest of Saccharomyces cerevisiae following DNA replication by a RAD9-dependent mechanism. In the present work, the authors have further investigated the implicit effects of chromosomal lesions on progression through meiosis by exposing yeast cells to X-irradiation at various times during sporulation. They find that exposure of RAD9 cells to X-irradiation early in meiosis prevents sporulation, arresting the cells at a stage prior to premeiotic DNA replication. rad9 meiotic cells are much less responsive to X-irradiation damage, completing sporulation after treatment with doses sufficient to cause arrest of RAD9 strains. These findings thereby reveal a RAD9-dependent checkpoint function in meiosis that is distinct from the G[sub 2] arrest previously shown to result from cdc 13 dysfunction. Analysis of the spores that continued to be produced by either RAD9 or rad9 cultures that were X-irradiated in later stages of sporulation revealed most spores to be viable, even after exposure to radiation doses sufficient to kill most vegetative cells. This finding demonstrates that the lesions induced by X-irradiation at later times fail to trigger the checkpoint function revealed by cdc 13 arrest and suggests that the lesions may be subject to repair by serving as intermediates in the recombination process. Strains mutant for chromosomal synapsis and recombination, and therefore defective in meiotic disjunction, were tested for evidence that X-ray-induced lesions might alleviate inviability by promoting recombination. Enhancement of spore viability when spo 11 (but not hop 1) diploids were X-irradiated during meiosis indicates that induced lesions may partially substitute for SPO 11-dependent functions that are required for the initiation of recombination. 74 refs., 3 figs., 6 tabs.

  8. Events associated with restoration by zinc of meiosis in apomictic Saccharomyces cerevisiae.

    PubMed Central

    Bilinski, C A; Miller, J J; Girvitz, S C

    1983-01-01

    The effects of nutritional alterations (carbon source and zinc) on nuclear division and protein synthesis during apomictic and meiotic development in Saccharomyces cerevisiae 19e1 were investigated. Unlike cells cultivated under meiosis-promoting conditions, cells cultured under apomixis-promoting conditions exhibited extensive protein synthesis during the first 3 h of incubation in sporulation medium, and nuclear divisions were evident during this time. Cycloheximide treatment of the latter cells induced meiosis, and maximum yields of meiotic asci resulted when this treatment was given for the first 3 h in sporulation medium. The results indicate that the decision concerning which developmental route cells will follow is made shortly after transfer to sporulation medium. Electrophoretic analysis of labeled proteins synthesized during sporulation revealed bands unique to both developmental routes. Images PMID:6350265

  9. From equator to pole: splitting chromosomes in mitosis and meiosis

    PubMed Central

    Duro, Eris

    2015-01-01

    During eukaryotic cell division, chromosomes must be precisely partitioned to daughter cells. This relies on a mechanism to move chromosomes in defined directions within the parental cell. While sister chromatids are segregated from one another in mitosis and meiosis II, specific adaptations enable the segregation of homologous chromosomes during meiosis I to reduce ploidy for gamete production. Many of the factors that drive these directed chromosome movements are known, and their molecular mechanism has started to be uncovered. Here we review the mechanisms of eukaryotic chromosome segregation, with a particular emphasis on the modifications that ensure the segregation of homologous chromosomes during meiosis I. PMID:25593304

  10. Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes

    PubMed Central

    Cabral, Gabriela; Marques, André; Schubert, Veit; Pedrosa-Harand, Andrea; Schlögelhofer, Peter

    2014-01-01

    Meiosis is a specialized cell division in sexually reproducing organisms before gamete formation. Following DNA replication, the canonical sequence in species with monocentric chromosomes is characterized by reductional segregation of homologous chromosomes during the first and equational segregation of sister chromatids during the second meiotic division. Species with holocentric chromosomes employ specific adaptations to ensure regular disjunction during meiosis. Here we present the analysis of two closely related plant species with holocentric chromosomes that display an inversion of the canonical meiotic sequence, with the equational division preceding the reductional. In-depth analysis of the meiotic divisions of Rhynchospora pubera and R. tenuis reveals that during meiosis I sister chromatids are bi-oriented, display amphitelic attachment to the spindle and are subsequently separated. During prophase II, chromatids are connected by thin chromatin threads that appear instrumental for the regular disjunction of homologous non-sister chromatids in meiosis II. PMID:25295686

  11. The spindle checkpoint and chromosome segregation in meiosis

    PubMed Central

    Gorbsky, Gary J.

    2014-01-01

    The spindle checkpoint is a key regulator of chromosome segregation in mitosis and meiosis. Its function is to prevent precocious anaphase onset before chromosomes have achieved bipolar attachment to the spindle. The spindle checkpoint comprises a complex set of signaling pathways that integrate microtubule dynamics, biomechanical forces at the kinetochores, and intricate regulation of protein interactions and post-translational modifications. Historically, many key observations that gave rise to the initial concepts of the spindle checkpoint were carried out in meiotic systems. In contrast with mitosis, the two distinct chromosome segregation events of meiosis present a special challenge for the regulation of checkpoint signaling. Preservation of fidelity in chromosome segregation in meiosis, controlled by the spindle checkpoint, also has significant impact in human health. This review highlights the contributions from meiotic systems in understanding the spindle checkpoint as well as the role of checkpoint signaling in controlling the complex divisions of meiosis. PMID:25470754

  12. Methylation of histone H3K23 blocks DNA damage in pericentric heterochromatin during meiosis

    PubMed Central

    Papazyan, Romeo; Voronina, Ekaterina; Chapman, Jessica R; Luperchio, Teresa R; Gilbert, Tonya M; Meier, Elizabeth; Mackintosh, Samuel G; Shabanowitz, Jeffrey; Tackett, Alan J; Reddy, Karen L; Coyne, Robert S; Hunt, Donald F; Liu, Yifan; Taverna, Sean D

    2014-01-01

    Despite the well-established role of heterochromatin in protecting chromosomal integrity during meiosis and mitosis, the contribution and extent of heterochromatic histone posttranslational modifications (PTMs) remain poorly defined. Here, we gained novel functional insight about heterochromatic PTMs by analyzing histone H3 purified from the heterochromatic germline micronucleus of the model organism Tetrahymena thermophila. Mass spectrometric sequencing of micronuclear H3 identified H3K23 trimethylation (H3K23me3), a previously uncharacterized PTM. H3K23me3 became particularly enriched during meiotic leptotene and zygotene in germline chromatin of Tetrahymena and C. elegans. Loss of H3K23me3 in Tetrahymena through deletion of the methyltransferase Ezl3p caused mislocalization of meiosis-induced DNA double-strand breaks (DSBs) to heterochromatin, and a decrease in progeny viability. These results show that an evolutionarily conserved developmental pathway regulates H3K23me3 during meiosis, and our studies in Tetrahymena suggest this pathway may function to protect heterochromatin from DSBs. DOI: http://dx.doi.org/10.7554/eLife.02996.001 PMID:25161194

  13. Meiosis evolves: adaptation to external and internal environments.

    PubMed

    Bomblies, Kirsten; Higgins, James D; Yant, Levi

    2015-10-01

    306 I. 306 II. 307 III. 312 IV. 317 V. 318 319 References 319 SUMMARY: Meiosis is essential for the fertility of most eukaryotes and its structures and progression are conserved across kingdoms. Yet many of its core proteins show evidence of rapid or adaptive evolution. What drives the evolution of meiosis proteins? How can constrained meiotic processes be modified in response to challenges without compromising their essential functions? In surveying the literature, we found evidence of two especially potent challenges to meiotic chromosome segregation that probably necessitate adaptive evolutionary responses: whole-genome duplication and abiotic environment, especially temperature. Evolutionary solutions to both kinds of challenge are likely to involve modification of homologous recombination and synapsis, probably via adjustments of core structural components important in meiosis I. Synthesizing these findings with broader patterns of meiosis gene evolution suggests that the structural components of meiosis coevolve as adaptive modules that may change in primary sequence and function while maintaining three-dimensional structures and protein interactions. The often sharp divergence of these genes among species probably reflects periodic modification of entire multiprotein complexes driven by genomic or environmental changes. We suggest that the pressures that cause meiosis to evolve to maintain fertility may cause pleiotropic alterations of global crossover rates. We highlight several important areas for future research. PMID:26075313

  14. Selection on Meiosis Genes in Diploid and Tetraploid Arabidopsis arenosa

    PubMed Central

    Wright, Kevin M.; Arnold, Brian; Xue, Katherine; Šurinová, Maria; O’Connell, Jeremy; Bomblies, Kirsten

    2015-01-01

    Meiotic chromosome segregation is critical for fertility across eukaryotes, and core meiotic processes are well conserved even between kingdoms. Nevertheless, recent work in animals has shown that at least some meiosis genes are highly diverse or strongly differentiated among populations. What drives this remains largely unknown. We previously showed that autotetraploid Arabidopsis arenosa evolved stable meiosis, likely through reduced crossover rates, and that associated with this there is strong evidence for selection in a subset of meiosis genes known to affect axis formation, synapsis, and crossover frequency. Here, we use genome-wide data to study the molecular evolution of 70 meiosis genes in a much wider sample of A. arenosa. We sample the polyploid lineage, a diploid lineage from the Carpathian Mountains, and a more distantly related diploid lineage from the adjacent, but biogeographically distinct Pannonian Basin. We find that not only did selection act on meiosis genes in the polyploid lineage but also independently on a smaller subset of meiosis genes in Pannonian diploids. Functionally related genes are targeted by selection in these distinct contexts, and in two cases, independent sweeps occurred in the same loci. The tetraploid lineage has sustained selection on more genes, has more amino acid changes in each, and these more often affect conserved or potentially functional sites. We hypothesize that Pannonian diploid and tetraploid A. arenosa experienced selection on structural proteins that mediate sister chromatid cohesion, the formation of meiotic chromosome axes, and synapsis, likely for different underlying reasons. PMID:25543117

  15. Ectopic Premolar Tooth in the Sigmoid Notch.

    PubMed

    Törenek, K; Akgül, H M; Bayrakdar, I S

    2016-01-01

    Impaction of a mandibular premolar is relatively uncommon. Ectopic placement is more unusual and there has been no discussion in the literature of an ectopic mandibular premolar in the coronoid process. In this case report, we present an impacted ectopic mandibular permanent premolar in the sigmoid notch (incisura mandibulae) region. Etiology of the tooth and treatment options are discussed and illustrated by Cone Beam Computed Tomography (CBCT) images. PMID:27547475

  16. Ectopic Premolar Tooth in the Sigmoid Notch

    PubMed Central

    Akgül, H. M.; Bayrakdar, I. S.

    2016-01-01

    Impaction of a mandibular premolar is relatively uncommon. Ectopic placement is more unusual and there has been no discussion in the literature of an ectopic mandibular premolar in the coronoid process. In this case report, we present an impacted ectopic mandibular permanent premolar in the sigmoid notch (incisura mandibulae) region. Etiology of the tooth and treatment options are discussed and illustrated by Cone Beam Computed Tomography (CBCT) images. PMID:27547475

  17. Ectopic expression of Bcl-XL or Ku70 protects human colon cancer cells (SW480) against curcumin-induced apoptosis while their down-regulation potentiates it.

    PubMed

    Rashmi, Ramachandran; Kumar, Santhosh; Karunagaran, Devarajan

    2004-10-01

    Curcumin, the yellow pigment derived from Curcuma longa, is known to induce apoptosis of several cancer cells. However, many cancer cells protect themselves by over-expressing antiapoptotic proteins such as Bcl-XL or Ku70. To study their role in curcumin-induced apoptosis, human colon cancer cells (SW480) were made to over-express or under-express Bcl-XL (by stable transfection) and Ku70 (by transient transfection) using plasmid constructs that express their genes in sense or antisense orientation, respectively. Stable cells that express Bax [Bax-GFP (green fluorescent protein)], a proapoptotic member of the Bcl-2 family, were also established. Curcumin-induced cell death and nuclear condensation was more in AsBcl-XL and AsKu70 cells that under-express Bcl-XL and Ku70, respectively, compared with the vector-transfected cells. Bcl-XL and Ku70 protected the cells by inhibiting the release of cytochrome c, Smac (second mitochondria derived activator of caspase) and apoptosis inducing factor (AIF), and the activation of caspases 9, 8 and 3 triggered by curcumin. AsBcl-XL and AsKu70 cells were more sensitive to curcumin through enhanced activation of caspases 9 and 3 and release of cytochrome c, Smac and AIF. Curcumin-induced activation of caspase 8 was blocked by Ku70 but not by Bcl-XL. However, caspase 8 activation by curcumin was accelerated in both AsBcl-XL and AsKu70 cells suggesting a possible feedback activation of caspase 8 by caspase 3. Bax-GFP cells were highly sensitized when Ku70 was down-regulated supporting the reported role of Ku70 in the retention of Bax within the cytosol. The study reveals the potential of antisense inhibition of antiapoptotic proteins as an effective strategy to tackle chemoresistant cancers with curcumin. PMID:15205359

  18. Links between ectopic fat and vascular disease in humans.

    PubMed

    Lim, Soo; Meigs, James B

    2014-09-01

    The average of overweight individual can have differential fat depots in target organs or specific compartments of the body. This ectopic fat distribution may be more of a predictive factor for cardiovascular risk than obesity. Abdominal visceral obesity, a representative ectopic fat, is robustly associated with insulin resistance and cardiovascular risk. Fat depots in the liver and muscle tissue cause adverse cardiometabolic risk by affecting glucose and lipid metabolism. Pericardial fat and perivascular fat affect coronary atherosclerosis, cardiac function, and hemodynamics. Fat around the neck is associated with systemic vascular resistance. Fat around the kidney may increase blood pressure and induce albuminuria. Fat accumulation in or around the pancreas alters glucose metabolism, conferring cardiovascular risk. Ectopic fat may act as an active endocrine and paracrine organ that releases various bioactive mediators that influence insulin resistance, glucose and lipid metabolism, coagulation, and inflammation, which all contribute to cardiovascular risk. Because both obese and apparently lean individuals can have ectopic fat, regional fat distribution may play an important role in the development of cardiovascular diseases in both nonobese and obese people. PMID:25035342

  19. Cutaneous ectopic schistosomiasis: diagnostic challenge.

    PubMed

    Barros, Cláudia Renata Castro do Rêgo; Maia, Daniela Cristina Caetano; dos Santos, Josemir Belo; Medeiros, Camila Carolina Queiroz; de Araújo, Jessica Guido

    2016-01-01

    Cutaneous schistosomiasis is a rare clinical manifestation of schistosomiasis, an infectious and parasitic disease, caused in Brazil by the trematode Schistosoma mansoni. The lesions are due to the deposition of eggs or, rarely, adult worms, usually involving the genital and groin areas. Extra-genital lesions occur mainly on the torso as papules of zosteriform appearance. The case of a patient with ectopic cutaneous schistosomiasis is reported in this article, due to the rarity of its occurrence and its difficult clinical diagnosis. PMID:26982792

  20. Novel Tools to Analyze the Function of Salmonella Effectors Show That SvpB Ectopic Expression Induces Cell Cycle Arrest in Tumor Cells

    PubMed Central

    Mesa-Pereira, Beatriz; Medina, Carlos; Camacho, Eva María; Flores, Amando; Santero, Eduardo

    2013-01-01

    In order to further characterize its role in pathogenesis and to establish whether its overproduction can lead to eukaryotic tumor cell death, Salmonella strains able to express its virulence factor SpvB (an ADP-ribosyl transferase enzyme) in a salicylate-inducible way have been constructed and analyzed in different eukaryotic tumor cell lines. To do so, the bacterial strains bearing the expression system have been constructed in a ∆purD background, which allows control of bacterial proliferation inside the eukaryotic cell. In the absence of bacterial proliferation, salicylate-induced SpvB production resulted in activation of caspases 3 and 7 and apoptotic cell death. The results clearly indicated that controlled SpvB production leads to F-actin depolimerization and either G1/S or G2/M phase arrest in all cell lines tested, thus shedding light on the function of SpvB in Salmonella pathogenesis. In the first place, the combined control of protein production by salicylate regulated vectors and bacterial growth by adenine concentration offers the possibility to study the role of Salmonella effectors during eukaryotic cells infection. In the second place, the salicylate-controlled expression of SpvB by the bacterium provides a way to evaluate the potential of other homologous or heterologous proteins as antitumor agents, and, eventually to construct novel potential tools for cancer therapy, given that Salmonella preferentially proliferates in tumors. PMID:24205236

  1. Unh1, an Ustilago maydis Ndt80-like protein, controls completion of tumor maturation, teliospore development, and meiosis.

    PubMed

    Doyle, Colleen E; Kitty Cheung, H Y; Spence, Kelsey L; Saville, Barry J

    2016-09-01

    In this study, Ustilago maydis Ndt80 homolog one, unh1, of the obligate sexual pathogen U. maydis,is described. Unh1 is the sole Ndt80-like DNA-binding protein inU. maydis. In this model basidiomycete, Unh1 plays a role in sexual development, influencing tumor maturation, teliospore development and subsequent meiotic completion. Teliospore formation was reduced in deletion mutants, and those that did form had unpigmented, hyaline cell walls, and germinated without completing meiosis. Constitutively expressing unh1 in haploid cells resulted in abnormal pigmentation, when grown in both potato dextrose broth and minimal medium, suggesting that pigmentation may be triggered by unh1 in U. maydis. The function of Unh1 in sexual development and pigment production depends on the presence of the Ndt80-like DNA-binding domain, identified within Unh1. In the absence of this domain, or when the binding domain was altered with targeted amino acid changes, ectopic expression of Unh1 failed to complement the unh1 deletion with regards to pigment production and sexual development. An investigation of U. maydis genes with upstream motifs similar to Ndt80 recognition sequences revealed that some have altered transcript levels in Δunh1 strains. We propose that the first characterized Ndt80-like DNA-binding protein in a basidiomycete, Unh1, acts as a transcription factor that is required for teliospore maturation and the completion of meiosis in U. maydis. PMID:27397931

  2. Evidence of ectopic recombination and a repeat-induced point (RIP) mutation in the genome of Sclerotinia sclerotiorum, the agent responsible for white mold.

    PubMed

    Goldfarb, Míriam; Santana, Mateus Ferreira; Salomão, Tânia Maria Fernandes; Queiroz, Marisa Vieira de; Barros, Everaldo Gonçalves de

    2016-01-01

    Two retrotransposons from the superfamilies Copia and Gypsy named as Copia-LTR_SS and Gypsy-LTR_SS, respectively, were identified in the genomic bank of Sclerotinia sclerotiorum. These transposable elements (TEs) contained direct and preserved long terminal repeats (LTR). Domains related to codified regions for gag protein, integrase, reverse transcriptase and RNAse H were identified in Copia-LTR_SS, whereas in Gypsy-LTR_SS only domains for gag, reverse transcriptase and RNAse H were found. The abundance of identified LTR-Solo suggested possible genetic recombination events in the S. sclerotiorum genome. Furthermore, alignment of the sequences for LTR elements from each superfamily suggested the presence of a RIP (repeat-induced point mutation) silencing mechanism that may directly affect the evolution of this species. PMID:27560652

  3. Evidence of ectopic recombination and a repeat-induced point (RIP) mutation in the genome of Sclerotinia sclerotiorum, the agent responsible for white mold

    PubMed Central

    Goldfarb, Míriam; Santana, Mateus Ferreira; Salomão, Tânia Maria Fernandes; de Queiroz, Marisa Vieira; de Barros, Everaldo Gonçalves

    2016-01-01

    Abstract Two retrotransposons from the superfamilies Copia and Gypsy named as Copia-LTR_SS and Gypsy-LTR_SS, respectively, were identified in the genomic bank of Sclerotinia sclerotiorum. These transposable elements (TEs) contained direct and preserved long terminal repeats (LTR). Domains related to codified regions for gag protein, integrase, reverse transcriptase and RNAse H were identified in Copia-LTR_SS, whereas in Gypsy-LTR_SS only domains for gag, reverse transcriptase and RNAse H were found. The abundance of identified LTR-Solo suggested possible genetic recombination events in the S. sclerotiorum genome. Furthermore, alignment of the sequences for LTR elements from each superfamily suggested the presence of a RIP (repeat-induced point mutation) silencing mechanism that may directly affect the evolution of this species. PMID:27560652

  4. Evidence of ectopic recombination and a repeat-induced point (RIP) mutation in the genome of Sclerotinia sclerotiorum, the agent responsible for white mold.

    PubMed

    Goldfarb, Míriam; Santana, Mateus Ferreira; Salomão, Tânia Maria Fernandes; Queiroz, Marisa Vieira de; Barros, Everaldo Gonçalves de

    2016-07-01

    Two retrotransposons from the superfamilies Copia and Gypsy named as Copia-LTR_SS and Gypsy-LTR_SS, respectively, were identified in the genomic bank of Sclerotinia sclerotiorum. These transposable elements (TEs) contained direct and preserved long terminal repeats (LTR). Domains related to codified regions for gag protein, integrase, reverse transcriptase and RNAse H were identified in Copia-LTR_SS, whereas in Gypsy-LTR_SS only domains for gag, reverse transcriptase and RNAse H were found. The abundance of identified LTR-Solo suggested possible genetic recombination events in the S. sclerotiorum genome. Furthermore, alignment of the sequences for LTR elements from each superfamily suggested the presence of a RIP (repeat-induced point mutation) silencing mechanism that may directly affect the evolution of this species. PMID:27392240

  5. Ectopic scrotum: A unique case report.

    PubMed

    Moorthy, H Krishna; Pillai, Biju S; Rathore, Renjeeth Singh; Mehta, Nisarg

    2015-01-01

    Ectopic scrotum is a rare congenital anomaly. Most common location is supra-inguinal. We present a case of left ectopic scrotum in a three year old boy with no associated congenital anomalies, who underwent successful scrotoplasty and orchiopexy. PMID:26425237

  6. Ectopic scrotum: A unique case report

    PubMed Central

    Moorthy, H. Krishna; Pillai, Biju S.; Rathore, Renjeeth Singh; Mehta, Nisarg

    2015-01-01

    Ectopic scrotum is a rare congenital anomaly. Most common location is supra-inguinal. We present a case of left ectopic scrotum in a three year old boy with no associated congenital anomalies, who underwent successful scrotoplasty and orchiopexy. PMID:26425237

  7. Possible link between ectopic pancreas and holoprosencephaly

    PubMed Central

    Kin, Tatsuya; Korbutt, Gregory S.; Shapiro, A.M. James

    2012-01-01

    We report on the incidental observation of ectopic pancreas in a donor for islet cell transplantation. The donor’s clinical and imaging presentation was definitive for holoprosencephaly. This case report discusses a possible link between ectopic pancreas and holoprosencephaly. PMID:22688061

  8. Ectopic breast cancer: A case report.

    PubMed

    Önel, Safa; Karateke, Faruk; Kuvvetli, Adnan; Özyazıcı, Sefa; Özdoğan, Mehmet

    2013-01-01

    Ectopic breast may be present at any site, from the axilla to the vulva, other than its normal location. Cysts, adenofibromas and rarely carcinomas have been reported in ectopic breasts. In this case report, we present a patient with ectopic breast cancer. The patient had a thickening and enlarging of her ectopic breast tissue, on the left arcus costarium. Tru-cut biopsy revealed "invasive lobular carcinoma". Left ectopic mastectomy and level I-II axillary dissection were performed and then chemotherapy+radiotherapy+endocrine therapy treatment was commenced. During follow up, the patient is doing well; in spite of R1 resection, she has no evidence of local recurrences or distant metastases. PMID:25931856

  9. MeioBase: a comprehensive database for meiosis.

    PubMed

    Li, Hao; Meng, Fanrui; Guo, Chunce; Wang, Yingxiang; Xie, Xiaojing; Zhu, Tiansheng; Zhou, Shuigeng; Ma, Hong; Shan, Hongyan; Kong, Hongzhi

    2014-01-01

    Meiosis is a special type of cell division process necessary for the sexual reproduction of all eukaryotes. The ever expanding meiosis research calls for an effective and specialized database that is not readily available yet. To fill this gap, we have developed a knowledge database MeioBase (http://meiosis.ibcas.ac.cn), which is comprised of two core parts, Resources and Tools. In the Resources part, a wealth of meiosis data collected by curation and manual review from published literatures and biological databases are integrated and organized into various sections, such as Cytology, Pathway, Species, Interaction, and Expression. In the Tools part, some useful tools have been integrated into MeioBase, such as Search, Download, Blast, Comparison, My Favorites, Submission, and Advice. With a simplified and efficient web interface, users are able to search against the database with gene model IDs or keywords, and batch download the data for local investigation. We believe that MeioBase can greatly facilitate the researches related to meiosis. PMID:25566299

  10. Unravelling the proteomic profile of rice meiocytes during early meiosis

    PubMed Central

    Collado-Romero, Melania; Alós, Enriqueta; Prieto, Pilar

    2014-01-01

    Transfer of genetic traits from wild or related species into cultivated rice is nowadays an important aim in rice breeding. Breeders use genetic crosses to introduce desirable genes from exotic germplasms into cultivated rice varieties. However, in many hybrids there is only a low level of pairing (if existing) and recombination at early meiosis between cultivated rice and wild relative chromosomes. With the objective of getting deeper into the knowledge of the proteins involved in early meiosis, when chromosomes associate correctly in pairs and recombine, the proteome of isolated rice meiocytes has been characterized by nLC-MS/MS at every stage of early meiosis (prophase I). Up to 1316 different proteins have been identified in rice isolated meiocytes in early meiosis, being 422 exclusively identified in early prophase I (leptotene, zygotene, or pachytene). The classification of proteins in functional groups showed that 167 were related to chromatin structure and remodeling, nucleic acid binding, cell-cycle regulation, and cytoskeleton. Moreover, the putative roles of 16 proteins which have not been previously associated to meiosis or were not identified in rice before, are also discussed namely: seven proteins involved in chromosome structure and remodeling, five regulatory proteins [such as SKP1 (OSK), a putative CDK2 like effector], a protein with RNA recognition motifs, a neddylation-related protein, and two microtubule-related proteins. Revealing the proteins involved in early meiotic processes could provide a valuable tool kit to manipulate chromosome associations during meiosis in rice breeding programs. The data have been deposited to the ProteomeXchange with the PXD001058 identifier. PMID:25104955

  11. Ectopic molar pregnancy: a case report

    PubMed Central

    Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; Fatemi, Hind El; Sekkal, Med; Laamarti, Afaf

    2012-01-01

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance. PMID:22655097

  12. Ectopic molar pregnancy: a case report.

    PubMed

    Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; El Fatemi, Hind; Sekkal, Med; Laamarti, Afaf

    2012-01-01

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance. PMID:22655097

  13. Achiasmate male meiosis in two Cymatia species (Hemiptera, Heteroptera, Corixidae)

    PubMed Central

    Stoianova, Desislava; Grozeva, Snejana; Simov, Nikolay; Kuznetsova, Valentina

    2015-01-01

    Abstract The karyotype and male meiosis, with a particular focus on the presence or absence of chiasmata between the homologs, were studied in the water boatman species Cymatia rogenhoferi (Fieber) and Cymatia coleoptrata (Fabricius) (Corixidae, Cymatiainae). It is shown that the species have 2n = 33 (28A+2m+X1X2Y) and 2n = 24 (20A+2m+XY) respectively, post-reduction of sex chromosomes, and achiasmate meiosis of an alignment type in males. Cytogenetic and some morphological diagnostic characters separating Cymatia Flor from the rest of Corixidae are discussed. PMID:26807038

  14. Students as "Humans Chromosomes" in Role-Playing Mitosis and Meiosis

    ERIC Educational Resources Information Center

    Chinnici, Joseph P.; Yue, Joyce W.; Torres, Kieron M.

    2004-01-01

    Students often find it challenging to understand mitosis and meiosis and determine their processes. To develop an easier way to understand these terms, students are asked to role-play mitosis and meiosis and students themselves act as human chromosomes, which help students to learn differences between mitosis and meiosis.

  15. Understanding a Basic Biological Process: Expert and Novice Models of Meiosis.

    ERIC Educational Resources Information Center

    Kindfield, Ann C. H.

    The results of a study of the meiosis models utilized by individuals at varying levels of expertise while reasoning about the process of meiosis are presented. Based on these results, the issues of sources of misconceptions/difficulties and the construction of a sound understanding of meiosis are discussed. Five individuals from each of three…

  16. Ectopic Schistosoma mansoni Eggs Inside a Lipoma.

    PubMed

    Sabino, Kelly Renata; Nunes, Maurício Buzelin; Petroianu, Andy

    2016-01-01

    Ectopic schistosomiasis is uncommon and tends to occur when the parasite's eggs or adult forms are located far from their normal site. This report presents the first described case of ectopic Schistosoma mansoni eggs inside a subcutaneous lipoma far from the tissues of this worm's life cycle and with no connection to either portal veins or any other vascular system. These eggs were found inside giant cells surrounded by inflammatory cells. In conclusion, in humans, ectopic S. mansoni eggs can be found far from the tissues of the described life cycle of this worm, with no connection to portal veins or other blood vessels used for their migration. PMID:26598562

  17. Formation of ectopic osteogenesis in weightlessness

    NASA Technical Reports Server (NTRS)

    1977-01-01

    An ectopic osteogenesis experiment aboard the Cosmos-936 biosatellite is described. Decalcified, lyophilized femur and tibia were implanted under the fascia or in the anterior wall of the abdomen in rats. Bone formation before and after the tests is described and illustrated. The extent of formation of ectopic bone in weightlessness did not differ significantly from that in the ground controls, but the bone marrow of the ectopic bone of the flight rats consisted exclusively of fat cells. The deficit of support-muscle loading was considered to cause the disturbance in skeletal bone tissue development.

  18. Renal Anomalies Associated with Ectopic Neurohypophysis

    PubMed Central

    Özen, Samim; Şişmek, Damla Gökşen; Önder, Asan; Darcan, Şükran

    2011-01-01

    Objective: Although the etiology of ectopic neurohypophysis that leads to pituitary hormone deficiencies is not yet clearly understood, birth trauma or genetic factors have been considered responsible. Concurrent cranial and extracranial congenital anomalies have been reported in such cases. The aim of the present study was to investigate the frequency of renal anomalies in nonsyndromic cases with ectopic neurohypophysis. Methods: We retrospectively evaluated the medical records of 20 patients with ectopic neurohypophysis who were followed up between January 1990 and December 2007 in a tertiary University Hospital. Results: Renal anomalies were identified in three (15%) cases including unilateral renal agenesis in one case, renal hypoplasia in one case, and double collecting system and unilateral renal agenesis in one case. Conclusions: In the present study, the increased frequency of renal anomalies in cases of ectopic neurohypophysis was highlighted, and it was emphasized that there might be common genetic factors that lead to such associations. Conflict of interest:None declared. PMID:21750632

  19. Trends in ectopic pregnancy in Canada.

    PubMed Central

    Hockin, J C; Jessamine, A G

    1984-01-01

    The incidence in Canada of one complication of sexually transmitted disease, ectopic pregnancy, was examined by age group for the years 1971 through 1980 by means of hospital statistics provided by Statistics Canada. The denominator was "reported pregnancies"--the total of live births, stillbirths, legal abortions and ectopic pregnancies in a given year. In 1980, 4123 ectopic pregnancies (9.3/1000 reported pregnancies) were reported, a 63% increase from 1970. The incidence had increased in each age stratum. This trend may be related to increasing rates of gonococcal infection and of hospitalization for pelvic inflammatory disease and lends confirmation to data from other countries that relate the increase in the rate of ectopic pregnancy to rising rates of sexually transmitted disease. PMID:6478362

  20. Ectopic Axillary Breast during Systemic Lupus

    PubMed Central

    Ben Dhaou, Besma; Boussema, Fatma; Aydi, Zohra; Baili, Lilia; Rokbani, Lilia

    2012-01-01

    Many breast changes may occur in systemic lupus erythematosus. We report a 41-year-old woman with lupus who presented three years after the onset of lupus an ectopic mammary gland confirmed by histological study. PMID:22924044

  1. Caesarean scar ectopic pregnancy: a case report

    PubMed Central

    Edwards, Hazel; Heggs, Karen; White, Donna

    2013-01-01

    This case study discusses a recent diagnosis of a rare form of ectopic pregnancy within a Caesarean section scar. Evidence indicates that the prevalence of this form of ectopic pregnancy is escalating due to the increasing number of Caesarean sections performed. As ultrasound plays a major role in diagnosing this rare life-threatening condition, we recommend key points for practitioners to consider for meticulous assessment and accurate diagnosis. PMID:27433207

  2. "Dropping Your Genes." A Genetics Simulation in Meiosis, Fertilization & Reproduction.

    ERIC Educational Resources Information Center

    Atkins, Thomas; Roderick, Joyce MacFall

    1991-01-01

    An activity that introduces students to the concepts of independent assortment of alleles during meiosis and gametogenesis, the richness of the variation that occurs as a result of allele recombination, and the unique phenotypes of offspring. Reproducible handouts with the directions and model chromosomes are provided. (KR)

  3. A computational approach to developing mathematical models of polyploid meiosis.

    PubMed

    Rehmsmeier, Marc

    2013-04-01

    Mathematical models of meiosis that relate offspring to parental genotypes through parameters such as meiotic recombination frequency have been difficult to develop for polyploids. Existing models have limitations with respect to their analytic potential, their compatibility with insights into mechanistic aspects of meiosis, and their treatment of model parameters in terms of parameter dependencies. In this article I put forward a computational approach to the probabilistic modeling of meiosis. A computer program enumerates all possible paths through the phases of replication, pairing, recombination, and segregation, while keeping track of the probabilities of the paths according to the various parameters involved. Probabilities for classes of genotypes or phenotypes are added, and the resulting formulas are simplified by the symbolic-computation system Mathematica. An example application to autotetraploids results in a model that remedies the limitations of previous models mentioned above. In addition to the immediate implications, the computational approach presented here can be expected to be useful through opening avenues for modeling a host of processes, including meiosis in higher-order ploidies. PMID:23335332

  4. Meiosis and haploid gametes in the pathogen Trypanosoma brucei.

    PubMed

    Peacock, Lori; Bailey, Mick; Carrington, Mark; Gibson, Wendy

    2014-01-20

    In eukaryote pathogens, sex is an important driving force in spreading genes for drug resistance, pathogenicity, and virulence. For the parasitic trypanosomes that cause African sleeping sickness, mating occurs during transmission by the tsetse vector and involves meiosis, but haploid gametes have not yet been identified. Here, we show that meiosis is a normal part of development in the insect salivary glands for all subspecies of Trypanosoma brucei, including the human pathogens. By observing insect-derived trypanosomes during the window of peak expression of meiosis-specific genes, we identified promastigote-like (PL) cells that interacted with each other via their flagella and underwent fusion, as visualized by the mixing of cytoplasmic red and green fluorescent proteins. PL cells had a short, wide body, a very long anterior flagellum, and either one or two kinetoplasts, but only the anterior kinetoplast was associated with the flagellum. Measurement of nuclear DNA contents showed that PL cells were haploid relative to diploid metacyclics. Trypanosomes are among the earliest diverging eukaryotes, and our results support the hypothesis that meiosis and sexual reproduction are ubiquitous in eukaryotes and likely to have been early innovations. PMID:24388851

  5. Meiosis: Cohesins Are Not Just for Sisters Any More.

    PubMed

    Cahoon, Cori K; Hawley, R Scott

    2016-07-11

    Multiple meiosis-specific cohesion proteins act to facilitate homolog segregation at the first meiotic division. A recent paper demonstrates that meiotic cohesins can be separated into two complexes, one that establishes and maintains intersister cohesion and one that promotes interhomolog adhesion by regulating synaptonemal complex assembly. PMID:27404236

  6. Using pool noodles to teach mitosis and meiosis.

    PubMed

    Locke, John; McDermid, Heather E

    2005-05-01

    Although mitosis and meiosis are fundamental to understanding genetics, students often find them difficult to learn. We suggest using common "pool noodles" as teaching aids to represent chromatids in classroom demonstrations. Students use these noodles to demonstrate the processes of synapsis, segregation, and recombination. Student feedback has been overwhelmingly positive. PMID:15781711

  7. Ectopic POU5F1 in the male germ lineage disrupts differentiation and spermatogenesis in mice.

    PubMed

    Zheng, Yu; Phillips, LeAnna J; Hartman, Rachel; An, Junhui; Dann, Christina T

    2016-10-01

    Expression levels of the pluripotency determinant, POU5F1, are tightly regulated to ensure appropriate differentiation during early embryogenesis. POU5F1 is also present in the spermatogonial stem cell/progenitor cell population in mice and it is downregulated as spermatogenesis progresses. To test if POU5F1 downregulation is required for SSCs to differentiate, we produced transgenic mice that ubiquitously express POU5F1 in Cre-expressing lineages. Using a Vasa-Cre driver to produce ectopic POU5F1 in all postnatal germ cells, we found that POU5F1 downregulation was necessary for spermatogonial expansion during the first wave of spermatogenesis and for the production of differentiated spermatogonia capable of undergoing meiosis. In contrast, undifferentiated spermatogonia were maintained throughout adulthood, consistent with a normal presence of POU5F1 in these cells. The results suggest that POU5F1 downregulation in differentiating spermatogonia is a necessary step for the progression of spermatogenesis. Further, the creation of a transgenic mouse model for conditional ectopic expression of POU5F1 may be a useful resource for studies of POU5F1 in other cell lineages, during tumorogenesis and cell fate reprogramming. PMID:27486267

  8. Specialization of B-Type Cyclins for Mitosis or Meiosis in S. Cerevisiae

    PubMed Central

    Dahmann, C.; Futcher, B.

    1995-01-01

    The CLB1, CLB2, and CLB3 genes encode B-type cyclins important for mitosis in Saccharomyces cerevisiae, while a fourth B-type cyclin gene, CLB4, has no clear role. The effects of homozygous clb mutations on meiosis were examined. Mutants homozygous for clb1 clb3, or for clb1 clb4, gave high levels of sporulation, but produced mainly two-spored asci instead of four-spored asci. The cells had completed meiosis I but not meiosis II, producing viable diploid ascospores. CLB1 and CLB4 seem to be much more important for meiosis than for mitosis and may play some special role in meiosis II. In contrast, CLB2 is important for mitosis but not meiosis. The level of Cdc28-Clb activity may be important in determining whether meiosis II will occur. PMID:7672594

  9. THE ARABIDOPSIS GENE TARDY ASYNCHRONOUS MEIOSIS IS REQUIRED FOR THE NORMAL PACE AND SYNCHRONY OF CELL DIVISION DURING MALE MEIOSIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Male meiosis in higher organisms features synchronous cell divisions in a large number of cells. It is not clear how this synchrony is achieved, nor is it known whether the synchrony is linked to the regulation of cell cycle progression. Here, we describe an Arabidopsis mutant, named tardy asynchron...

  10. Connexin 43 reboots meiosis and reseals blood-testis barrier following toxicant-mediated aspermatogenesis and barrier disruption.

    PubMed

    Li, Nan; Mruk, Dolores D; Mok, Ka-Wai; Li, Michelle W M; Wong, Chris K C; Lee, Will M; Han, Daishu; Silvestrini, Bruno; Cheng, C Yan

    2016-04-01

    Earlier studies have shown that rats treated with an acute dose of 1-(2,4-dichlorobenzyl)-1H-indazole-3-carbohydrazide (adjudin, a male contraceptive under development) causes permanent infertility due to irreversible blood-testis barrier (BTB) disruption even though the population of undifferentiated spermatogonia remains similar to normal rat testes, because spermatogonia fail to differentiate into spermatocytes to enter meiosis. Since other studies have illustrated the significance of connexin 43 (Cx43)-based gap junction in maintaining the homeostasis of BTB in the rat testis and the phenotypes of Sertoli cell-conditional Cx43 knockout mice share many of the similarities of the adjudin-treated rats, we sought to examine if overexpression of Cx43 in these adjudin-treated rats would reseal the disrupted BTB and reinitiate spermatogenesis. A full-length Cx43 cloned into mammalian expression vector pCI-neo was used to transfect testes of adjudin-treated ratsversusempty vector. It was found that overexpression of Cx43 indeed resealed the Sertoli cell tight junction-permeability barrier based on a functionalin vivoassay in tubules displaying signs of meiosis as noted by the presence of round spermatids. Thus, these findings suggest that overexpression of Cx43 reinitiated spermatogenesis at least through the steps of meiosis to generate round spermatids in testes of rats treated with an acute dose of adjudin that led to aspermatogenesis. It was also noted that the round spermatids underwent eventual degeneration with the formation of multinucleated cells following Cx43 overexpression due to the failure of spermiogenesis because no elongating/elongated spermatids were detected in any of the tubules examined. The mechanism by which overexpression of Cx43 reboots meiosis and rescues BTB function was also examined. In summary, overexpression of Cx43 in the testis with aspermatogenesis reboots meiosis and reseals toxicant-induced BTB disruption, even though it fails to

  11. Fragmentation of Care in Ectopic Pregnancy.

    PubMed

    Stulberg, Debra B; Dahlquist, Irma; Jarosch, Christina; Lindau, Stacy T

    2016-05-01

    Objectives Ectopic pregnancy is an important cause of maternal morbidity and mortality. Women who experience fragmented care may undergo unnecessary delays to diagnosis and treatment. Based on ectopic pregnancy cases observed in clinical practice that raised our concern about fragmentation of care, we designed an exploratory study to describe the number, characteristics, and outcomes of fragmented care among patients with ectopic pregnancy at one urban academic hospital. Methods Chart review with descriptive statistics. Fragmented care was defined as a patient being evaluated at an outside facility for possible ectopic pregnancy and transferred, referred, or discharged before receiving care at the study institution. Results Of 191 women seen for possible or definite ectopic pregnancy during the study period, 42 (22 %) met the study definition of fragmented care. The study was under-powered to observe statistically significant differences across groups, but we found concerning, non-significant trends: patients with fragmented care were more likely to be Medicaid recipients (65.9 vs. 58.8 %) and to experience a complication (23.8 vs. 18.1 %) compared to those with non-fragmented care. Most patients (n = 37) received no identifiable treatment prior to transfer and arrived to the study hospital with no communication to the receiving hospital from the outside provider (n = 34). Nine patients (21 %) presented with ruptured ectopic pregnancies. The fragmentation we observed in our study may contribute to previously identified socio-economic disparities in ectopic pregnancy outcomes. Conclusion If future research confirms these findings, health information exchanges and regional coordination of care may be important strategies for reducing maternal mortality. PMID:26987855

  12. Dynamic properties of meiosis-specific lamin C2 and its impact on nuclear envelope integrity

    PubMed Central

    Jahn, Daniel; Schramm, Sabine; Benavente, Ricardo

    2010-01-01

    A hallmark of meiosis is the precise pairing and the stable physical connection (synapsis) of the homologous chromosomes. These processes are essential prerequisite for their proper segregation. Pairing of the homologs during meiotic prophase I critically depends on characteristic movements of chromosomes. These movements, in turn, require attachment of meiotic telomeres to the nuclear envelope and their subsequent dynamic repositioning. Dynamic repositioning of meiotic telomeres goes along with profound structural reorganization of the nuclear envelope. The short A-type lamin C2 is thought to play a critical role in this process due to its specific expression during meiotic prophase I and the unique localization surrounding telomere attachments. Consistent with this notion, here we provide compelling evidence that meiosis-specific lamin C2 features a significantly increased mobility compared to somatic lamins as revealed by photobleaching techniques. We show that this property can be clearly ascribed to the lack of the N-terminal head and the significantly shorter α-helical coil domain. Moreover, expression of lamin C2 in somatic cells induces nuclear deformations and alters the distribution of the endogenous nuclear envelope proteins lamin B1, LAP2, SUN1 and SUN2. Together, our data define lamin C2 as a “natural lamin deletion mutant” that confers unique properties to the nuclear envelope which would be essential for dynamic telomere repositioning during meiotic prophase I. PMID:21327075

  13. Cohesin removal precedes topoisomerase IIα-dependent decatenation at centromeres in male mammalian meiosis II.

    PubMed

    Gómez, Rocío; Viera, Alberto; Berenguer, Inés; Llano, Elena; Pendás, Alberto M; Barbero, José Luis; Kikuchi, Akihiko; Suja, José A

    2014-03-01

    Sister chromatid cohesion is regulated by cohesin complexes and topoisomerase IIα. Although relevant studies have shed some light on the relationship between these two mechanisms of cohesion during mammalian mitosis, their interplay during mammalian meiosis remains unknown. In the present study, we have studied the dynamics of topoisomerase IIα in relation to that of the cohesin subunits RAD21 and REC8, the shugoshin-like 2 (Schizosaccharomyces pombe) (SGOL2) and the polo-like kinase 1-interacting checkpoint helicase (PICH), during both male mouse meiotic divisions. Our results strikingly show that topoisomerase IIα appears at stretched strands connecting the sister kinetochores of segregating early anaphase II chromatids, once the cohesin complexes have been removed from the centromeres. Moreover, the number and length of these topoisomerase IIα-connecting strands increase between lagging chromatids at anaphase II after the chemical inhibition of the enzymatic activity of topoisomerase IIα by etoposide. Our results also show that the etoposide-induced inhibition of topoisomerase IIα is not able to rescue the loss of centromere cohesion promoted by the absence of the shugoshin SGOL2 during anaphase I. Taking into account our results, we propose a two-step model for the sequential release of centromeric cohesion during male mammalian meiosis II. We suggest that the cohesin removal is a prerequisite for the posterior topoisomerase IIα-mediated resolution of persisting catenations between segregating chromatids during anaphase II. PMID:24013524

  14. Sirt6 depletion causes spindle defects and chromosome misalignment during meiosis of mouse oocyte

    PubMed Central

    Han, Longsen; Ge, Juan; Zhang, Liang; Ma, Rujun; Hou, Xiaojing; Li, Bin; Moley, Kelle; Wang, Qiang

    2015-01-01

    Sirt6, a member of the sirtuin family of NAD-dependent protein deacetylases, has been implicated in multiple biological processes. However, the roles of Sirt6 in meiosis have not been addressed. In the present study, by employing knockdown analysis in mouse oocytes, we evaluated the effects of Sirt6 on meiotic apparatus. We found that specific depletion of Sirt6 results in disruption of spindle morphology and chromosome alignment in oocytes. Consistent with this observation, incidence of aneuploidy is also markedly increased in Sirt6-depleted oocytes. Furthermore, confocal scanning showed that kinetochore-microtubule interaction, an important mechanism controlling chromosome segregation, is severely impaired in metaphase oocytes following Sirt6 knockdown. Unexpectedly, we discovered that Sirt6 modulates the acetylation status of histone H4K16 as their knockdown specifically induces the hyperacetylation of H4K16 in oocytes, which may be associated with the defective phenotypes described above via altering kinetochore function. Altogether, our data reveal a novel function of Sirt6 during oocyte meiosis and indicate a pathway regulating meiotic apparatus. PMID:26481302

  15. Phosphorylation of ARPP19 by protein kinase A prevents meiosis resumption in Xenopus oocytes

    PubMed Central

    Dupré, Aude; Daldello, Enrico M.; Nairn, Angus C.; Jessus, Catherine; Haccard, Olivier

    2014-01-01

    During oogenesis, oocytes are arrested in prophase and resume meiosis by activating the kinase Cdk1 upon hormonal stimulation. In all vertebrates, release from prophase arrest relies on protein kinase A (PKA) downregulation and on the dephosphorylation of a long-sought but still unidentified substrate. Here we show that ARPP19 is the PKA substrate whose phosphorylation at serine 109 is necessary and sufficient for maintaining Xenopus oocytes arrested in prophase. By downregulating PKA, progesterone, the meiotic inducer in Xenopus, promotes partial dephosphorylation of ARPP19 that is required for the formation of a threshold level of active Cdk1. Active Cdk1 then initiates MPF autoamplification loop that occurs independently of both PKA and ARPP19 phosphorylation at serine 109 but requires the Greatwall-dependent phosphorylation of ARPP19 at serine 67. Therefore, ARPP19 stands at a crossroads in the meiotic M-phase control network by integrating differential effects of PKA and Greatwall, two essential kinases for meiosis resumption. PMID:24525567

  16. Ectopic ganglion in cauda equina: case report.

    PubMed

    Conner, Andrew K; Fung, Kar-Ming; Peterson, Jo Elle G; Glenn, Chad A; Martin, Michael D

    2016-06-01

    Macroscopic ectopic or heterotopic ganglionic tissue within the cauda equina is a very rare pathological finding and is usually associated with spinal dysraphism. However, it may mimic genuine neoplasms of the cauda equina. The authors describe a 29-year-old woman with a history of back pain, right leg pain, and urinary incontinence in whom imaging demonstrated an enhancing mass located in the cauda equina at the L1-2 interspace. The patient subsequently underwent biopsy and was found to have a focus of ectopic ganglionic tissue that was 1.3 cm in greatest dimension. To the authors' knowledge, ectopic or heterotopic ganglionic tissue within the cauda equina in a patient without evidence of spinal dysraphism has never been reported. This patient presented with imaging and clinical findings suggestive of a neoplasm, and an open biopsy proved the lesion to be ectopic ganglionic tissue. The authors suggest that ectopic ganglionic tissue be added to the list of differential diagnoses of a space-occupying lesion arising from the cauda equina. PMID:26871650

  17. Ipl1/Aurora B kinase coordinates synaptonemal complex disassembly with cell cycle progression and crossover formation in budding yeast meiosis

    PubMed Central

    Jordan, Philip; Copsey, Alice; Newnham, Louise; Kolar, Elizabeth; Lichten, Michael; Hoffmann, Eva

    2009-01-01

    Several protein kinases collaborate to orchestrate and integrate cellular and chromosomal events at the G2/M transition in both mitotic and meiotic cells. During the G2/M transition in meiosis, this includes the completion of crossover recombination, spindle formation, and synaptonemal complex (SC) breakdown. We identified Ipl1/Aurora B kinase as the main regulator of SC disassembly. Mutants lacking Ipl1 or its kinase activity assemble SCs with normal timing, but fail to dissociate the central element component Zip1, as well as its binding partner, Smt3/SUMO, from chromosomes in a timely fashion. Moreover, lack of Ipl1 activity causes delayed SC disassembly in a cdc5 as well as a CDC5-inducible ndt80 mutant. Crossover levels in the ipl1 mutant are similar to those observed in wild type, indicating that full SC disassembly is not a prerequisite for joint molecule resolution and subsequent crossover formation. Moreover, expression of meiosis I and meiosis II-specific B-type cyclins occur normally in ipl1 mutants, despite delayed formation of anaphase I spindles. These observations suggest that Ipl1 coordinates changes to meiotic chromosome structure with resolution of crossovers and cell cycle progression at the end of meiotic prophase. PMID:19759266

  18. Licensing MLH1 sites for crossover during meiosis.

    PubMed

    Martín, Azahara C; Shaw, Peter; Phillips, Dylan; Reader, Steve; Moore, Graham

    2014-01-01

    During meiosis, homologous chromosomes synapse and recombine at sites marked by the binding of the mismatch repair protein MLH1. In hexaploid wheat, the Ph1 locus has a major effect on whether crossover occurs between homologues or between related homoeologues. Here we report that--in wheat-rye hybrids where homologues are absent--Ph1 affects neither the level of synapsis nor the number of MLH1. Thus in the case of wheat-wild relative hybrids, Ph1 must affect whether MLH1 sites are able to progress to crossover. The observed level of synapsis implies that Ph1 functions to promote homologue pairing rather than suppress homoeologue pairing in wheat. Therefore, Ph1 stabilises polyploidy in wheat by both promoting homologue pairing and preventing MLH1 sites from becoming crossovers on paired homoeologues during meiosis. PMID:25098240

  19. [Lithiasis and ectopic pelvic kidney. Therapeutic aspects].

    PubMed

    Aboutaieb, R; Rabii, R; el Moussaoui, A; Joual, A; Sarf, I; el Mrini, M; Benjelloun, S

    1996-01-01

    Kidney in ectopic position is dysplasic, and associated to other malformations. The advent of a lithiasis in these conditions rises questions about therapeutic options. We report on five observations of pelvic ectopic kidney with urinary lithiasis. Patients were aged from 16 to 42 years. Kidney was non functional in two cases, or with normal appearance sized 10 to 12 cm. We performed total nephrectomy in two cases, pyelolithotomy in the other cases. Surgical approach was subperitoneal via iliac route. A dismembered pyeloplasty was associated in one case. All patients did well. Radiologic control at 6 and 12 months showed no recurrence in a well functioning kidney. Surgical lithotomy is advocated as a treatment in urinary lithiasis affecting ectopic kidney. It is an easy procedure which permits correction of other associated malformations. PMID:9833030

  20. Partial diploidization of meiosis in autotetraploid Arabidopsis thaliana.

    PubMed Central

    Santos, J L; Alfaro, D; Sanchez-Moran, E; Armstrong, S J; Franklin, F C H; Jones, G H

    2003-01-01

    Meiosis was analyzed cytogenetically in autotetraploids of Arabidopsis, including both established lines and newly generated autotetraploid plants. Fluorescent in situ hybridization with 5S and 45S rDNA probes was used to identify the different chromosomes at metaphase I of meiosis. Multivalents were observed frequently in all the lines analyzed, but there were significant differences in multivalent frequency not only between the newly generated tetraploids and the established lines but also among the different established lines. The new tetraploids showed high multivalent frequencies, exceeding the theoretical 66.66% predicted by the simple random-end pairing model, in some cases significantly, thus indicating that Arabidopsis autotetraploids have more than two autonomous pairing sites per chromosome, despite their small sizes. The established lines showed fewer multivalents than the new autotetraploids did, but the extent of this reduction was strongly line and chromosome dependent. One line in particular showed a large reduction in multivalents and a concomitant increase in bivalents, while the other lines showed lesser reductions in multivalents. The reduction in multivalents was not uniformly distributed across chromosomes. The smaller chromosomes, especially chromosomes 2 and 4, showed the most marked reductions while the largest chromosome (1) showed virtually no reduction compared to the new tetraploids. It is concluded that the established autotetraploid lines have undergone a partial diploidization of meiosis, but not necessarily genetical diploidization, since their creation. Possible mechanisms for the resulting change in meiotic chromosome behavior are discussed. PMID:14668400

  1. Functions of Aurora kinase C in meiosis and cancer

    PubMed Central

    Quartuccio, Suzanne M.; Schindler, Karen

    2015-01-01

    The mammalian genome encodes three Aurora kinase protein family members: A, B, and C. While Aurora kinase A (AURKA) and B (AURKB) are found in cells throughout the body, significant protein levels of Aurora kinase C (AURKC) are limited to cells that undergo meiosis (sperm and oocyte). Despite its discovery nearly 20 years ago, we know little about the function of AURKC compared to that of the other 2 Aurora kinases. This lack of understanding can be attributed to the high sequence homology between AURKB and AURKC preventing the use of standard approaches to understand non-overlapping and meiosis I (MI)-specific functions of the two kinases. Recent evidence has revealed distinct functions of AURKC in meiosis and may aid in our understanding of why chromosome segregation during MI often goes awry in oocytes. Many cancers aberrantly express AURKC, but because we do not fully understand AURKC function in its normal cellular context, it is difficult to predict the biological significance of this expression on the disease. Here, we consolidate and update what is known about AURKC signaling in meiotic cells to better understand why it has oncogenic potential. PMID:26347867

  2. Meiosis and chromosome painting of sex chromosome systems in Ceboidea.

    PubMed

    Mudry, M D; Rahn, I M; Solari, A J

    2001-06-01

    The identity of the chromosomes involved in the multiple sex system of Alouatta caraya (Aca) and the possible distribution of this system among other Ceboidea were investigated by chromosome painting of mitotic cells from five species and by analysis of meiosis at pachytene in two species. The identity of the autosome #7 (X2) involved in the multiple system of Aca and its breakage points were demonstrated by both meiosis and chromosome painting. These features are identical to those described by Consigliere et al. [1996] in Alouatta seniculus sara (Assa) and Alouatta seniculus arctoidea (Asar). This multiple system was absent in the other four Ceboidea species studied here. However, data from the literature strongly suggest the presence of this multiple in other members of this genus. The presence of this multiple system among several species and subspecies that show high levels of chromosome rearrangements may suggest a special selective value of this multiple. The meiotic features of the sex systems of Aca and Cebus apella paraguayanus (Cap) are strikingly different at pachytene, as the latter system is similar to the sex pair of man and other primates. The relatively large genetic distances between species presently showing this multiple system suggest that its origin is not recent. Other members of the same genus should be investigated at meiosis and by chromosome painting in order to know the extent and distribution of this complex sex-chromosome system. PMID:11376445

  3. Ectopic suprasellar pituitary adenoma. A case report.

    PubMed

    Caranci, F; Cirillo, L; Bartiromo, F; Ferraioli, M; Del Basso De Caro, M L; Esposito, F; Cappabianca, P; Brunetti, A; Elefante, R

    2007-01-31

    The occurrence of a pituitary adenoma located entirely outside the sella turcica, so-called ectopic adenoma, is extremely rare. We report a case of a non secreting-pituitary adenoma located above the diaphragma sellae, with no invasion into the sella turcica, confirmed at surgery. The tumor was initially treated unsuccessfully by operations via the transphenoidal route. After initial negative exploration by the transphenoidal route, the patient was successfully treated by an endoscopic endonasal transphenoidal approach extended to the tuberculum sellae and the posterior planum sphenoidale to access the suprasellar supraglandular region. A brief review of ectopic adenomas and a discussion of the preoperative diagnosis are presented. PMID:24351300

  4. Distinct temporal requirements for autophagy and the proteasome in yeast meiosis.

    PubMed

    Wen, Fu-Ping; Guo, Yue-Shuai; Hu, Yang; Liu, Wei-Xiao; Wang, Qian; Wang, Yuan-Ting; Yu, Hai-Yan; Tang, Chao-Ming; Yang, Jun; Zhou, Tao; Xie, Zhi-Ping; Sha, Jia-Hao; Guo, Xuejiang; Li, Wei

    2016-04-01

    Meiosis is a special type of cellular renovation that involves 2 successive cell divisions and a single round of DNA replication. Two major degradation systems, the autophagy-lysosome and the ubiquitin-proteasome, are involved in meiosis, but their roles have yet to be elucidated. Here we show that autophagy mainly affects the initiation of meiosis but not the nuclear division. Autophagy works not only by serving as a dynamic recycling system but also by eliminating some negative meiotic regulators such as Ego4 (Ynr034w-a). In a quantitative proteomics study, the proteasome was found to be significantly upregulated during meiotic divisions. We found that proteasomal activity is essential to the 2 successive meiotic nuclear divisions but not for the initiation of meiosis. Our study defines the roles of autophagy and the proteasome in meiosis: Autophagy mainly affects the initiation of meiosis, whereas the proteasome mainly affects the 2 successive meiotic divisions. PMID:27050457

  5. Caesarean section scar ectopic pregnancy following postcoital contraception.

    PubMed

    Fabunmi, Laura; Perks, Nigel

    2002-07-01

    This is believed to be the first reported case of an ectopic pregnancy following failed progestogen-only emergency contraception. The ectopic pregnancy was at the site of a previous caesarean section scar and was managed conservatively. PMID:16259837

  6. Syndromes resulting from ectopic hormone-producing tumors.

    PubMed

    Gomez-Uria, A; Pazianos, A G

    1975-03-01

    Among the malignant tumors of nonendocrine origin that are capable of producing polypeptide hormones and of manifesting as different endocrine syndromes discussed here are ectopic ACTH syndrome, SIADH, and ectopic gonadotropin-producing tumors. PMID:163945

  7. [Ectopic pancreas imitating gastric neoplasm -- a case report].

    PubMed

    Buczek, Tomasz; Puzdrowski, Witold; Lenekowski, Radosław; Kruszewski, Wiesław Janusz

    2013-01-01

    Ectopic pancreas is a rare developmental disorder. Usually is asymptomatic. Most frequently is diagnosed in its gastric location accidentally during endoscopy. A patient with ectopic pancreas was described manifesting as a gastric tumor arousing oncological concern. PMID:24455840

  8. Mouse HORMAD1 is a meiosis i checkpoint protein that modulates DNA double- strand break repair during female meiosis.

    PubMed

    Shin, Yong-Hyun; McGuire, Megan M; Rajkovic, Aleksandar

    2013-08-01

    Oocytes in embryonic ovaries enter meiosis I and arrest in the diplonema stage. Perturbations in meiosis I, such as abnormal double-strand break (DSB) formation and repair, adversely affect oocyte survival. We previously discovered that HORMAD1 is a critical component of the synaptonemal complex but not essential for oocyte survival. No significant differences were observed in the number of primordial, primary, secondary, and developing follicles between wild-type and Hormad1(−/−)newborn, 8-day, and 80-day ovaries. Meiosis I progression in Hormad1(−/−) embryonic ovaries was normal through the zygotene stage and in oocytes arrested in diplonema; however, we did not visualize oocytes with completely synapsed chromosomes. We investigated effects of HORMAD1 deficiency on the kinetics of DNA DSB formation and repair in the mouse ovary. We irradiated Embryonic Day 16.5 wild-type and Hormad1(−/−) ovaries and monitored DSB repair using gammaH2AX, RAD51, and DMC1 immunofluorescence. Our results showed a significant drop in unrepaired DSBs in the irradiated Hormad1(−/−) zygotene oocytes as compared to the wild-type oocytes. Moreover, Hormad1 deficiency rescued Dmc1(−/−) oocytes. These results indicate that Hormad1 deficiency promotes DMC1-independent DSB repairs, which in turn helps asynaptic Hormad1(−/−) oocytes resist perinatal loss. PMID:23759310

  9. The SMC-5/6 Complex and the HIM-6 (BLM) Helicase Synergistically Promote Meiotic Recombination Intermediate Processing and Chromosome Maturation during Caenorhabditis elegans Meiosis

    PubMed Central

    Hong, Ye; Sonneville, Remi; Agostinho, Ana; Meier, Bettina; Wang, Bin; Blow, J. Julian; Gartner, Anton

    2016-01-01

    Meiotic recombination is essential for the repair of programmed double strand breaks (DSBs) to generate crossovers (COs) during meiosis. The efficient processing of meiotic recombination intermediates not only needs various resolvases but also requires proper meiotic chromosome structure. The Smc5/6 complex belongs to the structural maintenance of chromosome (SMC) family and is closely related to cohesin and condensin. Although the Smc5/6 complex has been implicated in the processing of recombination intermediates during meiosis, it is not known how Smc5/6 controls meiotic DSB repair. Here, using Caenorhabditis elegans we show that the SMC-5/6 complex acts synergistically with HIM-6, an ortholog of the human Bloom syndrome helicase (BLM) during meiotic recombination. The concerted action of the SMC-5/6 complex and HIM-6 is important for processing recombination intermediates, CO regulation and bivalent maturation. Careful examination of meiotic chromosomal morphology reveals an accumulation of inter-chromosomal bridges in smc-5; him-6 double mutants, leading to compromised chromosome segregation during meiotic cell divisions. Interestingly, we found that the lethality of smc-5; him-6 can be rescued by loss of the conserved BRCA1 ortholog BRC-1. Furthermore, the combined deletion of smc-5 and him-6 leads to an irregular distribution of condensin and to chromosome decondensation defects reminiscent of condensin depletion. Lethality conferred by condensin depletion can also be rescued by BRC-1 depletion. Our results suggest that SMC-5/6 and HIM-6 can synergistically regulate recombination intermediate metabolism and suppress ectopic recombination by controlling chromosome architecture during meiosis. PMID:27010650

  10. The SMC-5/6 Complex and the HIM-6 (BLM) Helicase Synergistically Promote Meiotic Recombination Intermediate Processing and Chromosome Maturation during Caenorhabditis elegans Meiosis.

    PubMed

    Hong, Ye; Sonneville, Remi; Agostinho, Ana; Meier, Bettina; Wang, Bin; Blow, J Julian; Gartner, Anton

    2016-03-01

    Meiotic recombination is essential for the repair of programmed double strand breaks (DSBs) to generate crossovers (COs) during meiosis. The efficient processing of meiotic recombination intermediates not only needs various resolvases but also requires proper meiotic chromosome structure. The Smc5/6 complex belongs to the structural maintenance of chromosome (SMC) family and is closely related to cohesin and condensin. Although the Smc5/6 complex has been implicated in the processing of recombination intermediates during meiosis, it is not known how Smc5/6 controls meiotic DSB repair. Here, using Caenorhabditis elegans we show that the SMC-5/6 complex acts synergistically with HIM-6, an ortholog of the human Bloom syndrome helicase (BLM) during meiotic recombination. The concerted action of the SMC-5/6 complex and HIM-6 is important for processing recombination intermediates, CO regulation and bivalent maturation. Careful examination of meiotic chromosomal morphology reveals an accumulation of inter-chromosomal bridges in smc-5; him-6 double mutants, leading to compromised chromosome segregation during meiotic cell divisions. Interestingly, we found that the lethality of smc-5; him-6 can be rescued by loss of the conserved BRCA1 ortholog BRC-1. Furthermore, the combined deletion of smc-5 and him-6 leads to an irregular distribution of condensin and to chromosome decondensation defects reminiscent of condensin depletion. Lethality conferred by condensin depletion can also be rescued by BRC-1 depletion. Our results suggest that SMC-5/6 and HIM-6 can synergistically regulate recombination intermediate metabolism and suppress ectopic recombination by controlling chromosome architecture during meiosis. PMID:27010650

  11. Effect of inhibition of sterol delta 14-reductase on accumulation of meiosis-activating sterol and meiotic resumption in cumulus-enclosed mouse oocytes in vitro.

    PubMed

    Leonardsen, L; Strömstedt, M; Jacobsen, D; Kristensen, K S; Baltsen, M; Andersen, C Y; Byskov, A G

    2000-01-01

    Two sterols of the cholesterol biosynthetic pathway induce resumption of meiosis in mouse oocytes in vitro. The sterols, termed meiosis-activating sterols (MAS), have been isolated from human follicular fluid (FF-MAS, 4,4-dimethyl-5 alpha-cholest-8,14,24-triene-3 beta-ol) and from bull testicular tissue (T-MAS, 4,4-dimethyl-5 alpha-cholest-8,24-diene-3 beta-ol). FF-MAS is the first intermediate in the cholesterol biosynthesis from lanosterol and is converted to T-MAS by sterol delta 14-reductase. An inhibitor of delta 7-reductase and delta 14 reductase, AY9944-A-7, causes cells with a constitutive cholesterol biosynthesis to accumulate FF-MAS and possibly other intermediates between lanosterol and cholesterol. The aim of the present study was to evaluate whether AY9944-A-7 added to cultures of cumulus-oocyte complexes (COC) from mice resulted in accumulation of MAS and meiotic maturation. AY9944-A-7 stimulated dose dependently (5-25 mumol l-1) COC to resume meiosis when cultured for 22 h in alpha minimal essential medium (alpha-MEM) containing 4 mmol hypoxanthine l-1, a natural inhibitor of meiotic maturation. In contrast, naked oocytes were not induced to resume meiosis by AY9944-A-7. When cumulus cells were separated from their oocytes and co-cultured, AY9944-A-7 did not affect resumption of meiosis, indicating that intact oocyte-cumulus cell connections are important for AY9944-A-7 to exert its effect on meiosis. Cultures of COC with 10 mumol AY9944-A-7 l-1 in the presence of [3H]mevalonic acid, a natural precursor for steroid synthesis, resulted in accumulation of labelled FF-MAS, which had an 11-fold greater amount of radioactivity incorporated per COC compared with the control culture without AY9944-A-7. In contrast, incorporation of radioactivity into the cholesterol fraction was reduced 30-fold in extracts from the same oocytes. The present findings demonstrate for the first time that COC can synthesize cholesterol from mevalonate and accumulate FF-MAS in

  12. An Ectopic ACTH Secreting Metastatic Parotid Tumour

    PubMed Central

    Dacruz, Thomas; Kalhan, Atul; Rashid, Majid; Obuobie, Kofi

    2016-01-01

    A 60-year old woman presented with features of Cushing's syndrome (CS) secondary to an ectopic adrenocorticotropic hormone (ACTH) secreting metastatic parotid tumour 3 years after excision of the original tumour. She subsequently developed fatal intestinal perforation and unfortunately died despite best possible medical measures. Ectopic ACTH secretion accounts for 5–10% of all patients presenting with ACTH dependent hypercortisolism; small cell carcinoma of lung (SCLC) and neuroendocrine tumours (NET) account for the majority of such cases. Although there are 4 previous case reports of ectopic ACTH secreting salivary tumours in literature, to our knowledge this is the first published case report in which the CS developed after 3 years of what was deemed as a successful surgical excision of primary salivary tumour. Our patient initially had nonspecific symptoms which may have contributed to a delay in diagnosis. Perforation of sigmoid colon is a recognised though underdiagnosed complication associated with steroid therapy and hypercortisolism. This case demonstrates the challenges faced in diagnosis as well as management of patients with CS apart from the practical difficulties faced while trying to identify source of ectopic ACTH. PMID:26904316

  13. An Ectopic ACTH Secreting Metastatic Parotid Tumour.

    PubMed

    Dacruz, Thomas; Kalhan, Atul; Rashid, Majid; Obuobie, Kofi

    2016-01-01

    A 60-year old woman presented with features of Cushing's syndrome (CS) secondary to an ectopic adrenocorticotropic hormone (ACTH) secreting metastatic parotid tumour 3 years after excision of the original tumour. She subsequently developed fatal intestinal perforation and unfortunately died despite best possible medical measures. Ectopic ACTH secretion accounts for 5-10% of all patients presenting with ACTH dependent hypercortisolism; small cell carcinoma of lung (SCLC) and neuroendocrine tumours (NET) account for the majority of such cases. Although there are 4 previous case reports of ectopic ACTH secreting salivary tumours in literature, to our knowledge this is the first published case report in which the CS developed after 3 years of what was deemed as a successful surgical excision of primary salivary tumour. Our patient initially had nonspecific symptoms which may have contributed to a delay in diagnosis. Perforation of sigmoid colon is a recognised though underdiagnosed complication associated with steroid therapy and hypercortisolism. This case demonstrates the challenges faced in diagnosis as well as management of patients with CS apart from the practical difficulties faced while trying to identify source of ectopic ACTH. PMID:26904316

  14. Ectopic decidual reaction mimicking inguinal lymphoma on ultrasound

    PubMed Central

    Prangsgaard, T; Lorentzen, T

    2014-01-01

    Ectopic decidual reaction has been described in various intraperitoneal locations. We present a case of unusual ectopic decidual reaction in the groin mimicking inguinal lymphoma on ultrasound in a pregnant woman. This case contributes evidence illustrating the variability of the clinical presentation of ectopic decidual reaction.

  15. Role of animal pole protuberance and microtubules during meiosis in sea cucumber Apostichopus japonicus oocytes

    NASA Astrophysics Data System (ADS)

    Pang, Zhenguo; Chang, Yaqing; Sun, Huiling; Yu, Jiaping

    2010-05-01

    Fully grown oocytes of Apostichopus japonicus have a cytoplasmic protuberance where the oocyte attaches to the follicle. The protuberance and the oolamina located on the opposite side of the oocyte indicate the animal-vegetal axis. Two pre-meiotic centrosomes are anchored to the protuberance by microtubules between centrosomes and protuberance. After meiosis reinitiation induced by DTT solution, the germinal vesicle (GV) migrates towards the protuberance. The GV breaks down after it migrates to the oocyte membrane on the protuberance side. The protuberance then contracts back into the oocyte and the first polar body extrudes from the site of the former protuberance. The second polar body forms beneath the first. Thus the oocyte protuberance indicates the presumptive animal pole well before maturation of the oocyte.

  16. Ectopic Expression of Retrotransposon-Derived PEG11/RTL1 Contributes to the Callipyge Muscular Hypertrophy

    PubMed Central

    Xu, Xuewen; Ectors, Fabien; Davis, Erica E.; Pirottin, Dimitri; Cheng, Huijun; Farnir, Frédéric; Hadfield, Tracy; Cockett, Noelle; Charlier, Carole; Georges, Michel; Takeda, Haruko

    2015-01-01

    The callipyge phenotype is an ovine muscular hypertrophy characterized by polar overdominance: only heterozygous +Mat/CLPGPat animals receiving the CLPG mutation from their father express the phenotype. +Mat/CLPGPat animals are characterized by postnatal, ectopic expression of Delta-like 1 homologue (DLK1) and Paternally expressed gene 11/Retrotransposon-like 1 (PEG11/RTL1) proteins in skeletal muscle. We showed previously in transgenic mice that ectopic expression of DLK1 alone induces a muscular hypertrophy, hence demonstrating a role for DLK1 in determining the callipyge hypertrophy. We herein describe newly generated transgenic mice that ectopically express PEG11 in skeletal muscle, and show that they also exhibit a muscular hypertrophy phenotype. Our data suggest that both DLK1 and PEG11 act together in causing the muscular hypertrophy of callipyge sheep. PMID:26474044

  17. Functional specialization of chordate CDK1 paralogs during oogenic meiosis

    PubMed Central

    Øvrebø, Jan Inge; Campsteijn, Coen; Kourtesis, Ioannis; Hausen, Harald; Raasholm, Martina; Thompson, Eric M

    2015-01-01

    Cyclin-dependent kinases (CDKs) are central regulators of eukaryotic cell cycle progression. In contrast to interphase CDKs, the mitotic phase CDK1 is the only CDK capable of driving the entire cell cycle and it can do so from yeast to mammals. Interestingly, plants and the marine chordate, Oikopleura dioica, possess paralogs of the highly conserved CDK1 regulator. However, whereas in plants the 2 CDK1 paralogs replace interphase CDK functions, O. dioica has a full complement of interphase CDKs in addition to its 5 odCDK1 paralogs. Here we show specific sub-functionalization of odCDK1 paralogs during oogenesis. Differential spatiotemporal dynamics of the odCDK1a, d and e paralogs and the meiotic polo-like kinase 1 (Plk1) and aurora kinase determine the subset of meiotic nuclei in prophase I arrest that will seed growing oocytes and complete meiosis. Whereas we find odCDK1e to be non-essential, knockdown of the odCDK1a paralog resulted in the spawning of non-viable oocytes of reduced size. Knockdown of odCDK1d also resulted in the spawning of non-viable oocytes. In this case, the oocytes were of normal size, but were unable to extrude polar bodies upon exposure to sperm, because they were unable to resume meiosis from prophase I arrest, a classical function of the sole CDK1 during meiosis in other organisms. Thus, we reveal specific sub-functionalization of CDK1 paralogs, during the meiotic oogenic program. PMID:25714331

  18. Functional specialization of chordate CDK1 paralogs during oogenic meiosis.

    PubMed

    Øvrebø, Jan Inge; Campsteijn, Coen; Kourtesis, Ioannis; Hausen, Harald; Raasholm, Martina; Thompson, Eric M

    2015-01-01

    Cyclin-dependent kinases (CDKs) are central regulators of eukaryotic cell cycle progression. In contrast to interphase CDKs, the mitotic phase CDK1 is the only CDK capable of driving the entire cell cycle and it can do so from yeast to mammals. Interestingly, plants and the marine chordate, Oikopleura dioica, possess paralogs of the highly conserved CDK1 regulator. However, whereas in plants the 2 CDK1 paralogs replace interphase CDK functions, O. dioica has a full complement of interphase CDKs in addition to its 5 odCDK1 paralogs. Here we show specific sub-functionalization of odCDK1 paralogs during oogenesis. Differential spatiotemporal dynamics of the odCDK1a, d and e paralogs and the meiotic polo-like kinase 1 (Plk1) and aurora kinase determine the subset of meiotic nuclei in prophase I arrest that will seed growing oocytes and complete meiosis. Whereas we find odCDK1e to be non-essential, knockdown of the odCDK1a paralog resulted in the spawning of non-viable oocytes of reduced size. Knockdown of odCDK1d also resulted in the spawning of non-viable oocytes. In this case, the oocytes were of normal size, but were unable to extrude polar bodies upon exposure to sperm, because they were unable to resume meiosis from prophase I arrest, a classical function of the sole CDK1 during meiosis in other organisms. Thus, we reveal specific sub-functionalization of CDK1 paralogs, during the meiotic oogenic program. PMID:25714331

  19. Immunolocalization on Whole Anther Chromosome Spreads for Male Meiosis.

    PubMed

    Dukowic-Schulze, Stefanie; Harris, Anthony; Chen, Changbin

    2016-01-01

    Immunolocalization of cells undergoing meiosis has proven to be one of the most important tools to decipher chromatin-associated protein dynamics and causal relationships. Here, we describe a protocol established for maize which is easily adaptable to other plants, for example, with minor modifications to Arabidopsis as stated here. In contrast to many other protocols, the following protocol is based on fixation by a 3:1 mixture of ethanol and acetic acid. Spreading of cells is followed by freeze-shattering, protein antigenicity retrieval by a hot citrate buffer bath, antibody incubations and washes, and DNA staining. PMID:27511174

  20. Restoration of Vision with Ectopic Expression of Human Rod Opsin.

    PubMed

    Cehajic-Kapetanovic, Jasmina; Eleftheriou, Cyril; Allen, Annette E; Milosavljevic, Nina; Pienaar, Abigail; Bedford, Robert; Davis, Katherine E; Bishop, Paul N; Lucas, Robert J

    2015-08-17

    Many retinal dystrophies result in photoreceptor loss, but the inner retinal neurons can survive, making them potentially amenable to emerging optogenetic therapies. Here, we show that ectopically expressed human rod opsin, driven by either a non-selective or ON-bipolar cell-specific promoter, can function outside native photoreceptors and restore visual function in a mouse model of advanced retinal degeneration. Electrophysiological recordings from retinal explants and the visual thalamus revealed changes in firing (increases and decreases) induced by simple light pulses, luminance increases, and naturalistic movies in treated mice. These responses could be elicited at light intensities within the physiological range and substantially below those required by other optogenetic strategies. Mice with rod opsin expression driven by the ON-bipolar specific promoter displayed behavioral responses to increases in luminance, flicker, coarse spatial patterns, and elements of a natural movie at levels of contrast and illuminance (≈50-100 lux) typical of natural indoor environments. These data reveal that virally mediated ectopic expression of human rod opsin can restore vision under natural viewing conditions and at moderate light intensities. Given the inherent advantages in employing a human protein, the simplicity of this intervention, and the quality of vision restored, we suggest that rod opsin merits consideration as an optogenetic actuator for treating patients with advanced retinal degeneration. PMID:26234216

  1. Restoration of Vision with Ectopic Expression of Human Rod Opsin

    PubMed Central

    Cehajic-Kapetanovic, Jasmina; Eleftheriou, Cyril; Allen, Annette E.; Milosavljevic, Nina; Pienaar, Abigail; Bedford, Robert; Davis, Katherine E.; Bishop, Paul N.; Lucas, Robert J.

    2015-01-01

    Summary Many retinal dystrophies result in photoreceptor loss, but the inner retinal neurons can survive, making them potentially amenable to emerging optogenetic therapies. Here, we show that ectopically expressed human rod opsin, driven by either a non-selective or ON-bipolar cell-specific promoter, can function outside native photoreceptors and restore visual function in a mouse model of advanced retinal degeneration. Electrophysiological recordings from retinal explants and the visual thalamus revealed changes in firing (increases and decreases) induced by simple light pulses, luminance increases, and naturalistic movies in treated mice. These responses could be elicited at light intensities within the physiological range and substantially below those required by other optogenetic strategies. Mice with rod opsin expression driven by the ON-bipolar specific promoter displayed behavioral responses to increases in luminance, flicker, coarse spatial patterns, and elements of a natural movie at levels of contrast and illuminance (≈50–100 lux) typical of natural indoor environments. These data reveal that virally mediated ectopic expression of human rod opsin can restore vision under natural viewing conditions and at moderate light intensities. Given the inherent advantages in employing a human protein, the simplicity of this intervention, and the quality of vision restored, we suggest that rod opsin merits consideration as an optogenetic actuator for treating patients with advanced retinal degeneration. PMID:26234216

  2. Shugoshin1 May Play Important Roles in Separation of Homologous Chromosomes and Sister Chromatids during Mouse Oocyte Meiosis

    PubMed Central

    Yin, Shen; Ai, Jun-Shu; Shi, Li-Hong; Wei, Liang; Yuan, Ju; Ouyang, Ying-Chun; Hou, Yi; Chen, Da-Yuan; Schatten, Heide; Sun, Qing-Yuan

    2008-01-01

    Background Homologous chromosomes separate in meiosis I and sister chromatids separate in meiosis II, generating haploid gametes. To address the question why sister chromatids do not separate in meiosis I, we explored the roles of Shogoshin1 (Sgo1) in chromosome separation during oocyte meiosis. Methodology/Principal Findings Sgo1 function was evaluated by exogenous overexpression to enhance its roles and RNAi to suppress its roles during two meioses of mouse oocytes. Immunocytochemistry and chromosome spread were used to evaluate phenotypes. The exogenous Sgo1 overexpression kept homologous chromosomes and sister chromatids not to separate in meiosis I and meiosis II, respectively, while the Sgo1 RNAi promoted premature separation of sister chromatids. Conclusions Our results reveal that prevention of premature separation of sister chromatids in meiosis I requires the retention of centromeric Sgo1, while normal separation of sister chromatids in meiosis II requires loss of centromeric Sgo1. PMID:18949044

  3. First-Year Biology Students' Understandings of Meiosis: An Investigation Using a Structural Theoretical Framework

    ERIC Educational Resources Information Center

    Quinn, Frances; Pegg, John; Panizzon, Debra

    2009-01-01

    Meiosis is a biological concept that is both complex and important for students to learn. This study aims to explore first-year biology students' explanations of the process of meiosis, using an explicit theoretical framework provided by the Structure of the Observed Learning Outcome (SOLO) model. The research was based on responses of 334…

  4. An Interactive Modeling Lesson Increases Students' Understanding of Ploidy during Meiosis

    ERIC Educational Resources Information Center

    Wright, L. Kate; Newman, Dina L.

    2011-01-01

    Chromosome structure is confusing to students at all levels, and chromosome behavior during meiosis is a notoriously difficult topic. Undergraduate biology majors are exposed to the process of meiosis numerous times during their presecondary and postsecondary education, yet understanding of key concepts, such as the point at which haploidy is…

  5. Close, stable homolog juxtaposition during meiosis in budding yeast is dependent on meiotic recombination, occurs independently of synapsis, and is distinct from DSB-independent pairing contacts

    PubMed Central

    Peoples, Tamara L.; Dean, Eric; Gonzalez, Oscar; Lambourne, Lindsey; Burgess, Sean M.

    2002-01-01

    A site-specific recombination system that probes the relative probabilities that pairs of chromosomal loci collide with one another in living cells of budding yeast was used to explore the relative contributions of pairing, recombination, synaptonemal complex formation, and telomere clustering to the close juxtaposition of homologous chromosome pairs during meiosis. The level of Cre-mediated recombination between a pair of loxP sites located at an allelic position on homologous chromosomes was 13-fold greater than that between a pair of loxP sites located at ectopic positions on nonhomologous chromosomes. Mutations affecting meiotic recombination initiation and the processing of DNA double-strand breaks (DSBs) into single-end invasions (SEIs) reduced the levels of allelic Cre-mediated recombination levels by three- to sixfold. The severity of Cre/loxP phenotypes is presented in contrast to relatively weak DSB-independent pairing defects as assayed using fluorescence in situ hybridization for these mutants. Mutations affecting synaptonemal complex (SC) formation or crossover control gave wild-type levels of allelic Cre-mediated recombination. A delay in attaining maximum levels of allelic Cre-mediated recombination was observed for a mutant defective in telomere clustering. None of the mutants affected ectopic levels of recombination. These data suggest that stable, close homolog juxtaposition in yeast is distinct from pre-DSB pairing interactions, requires both DSB and SEI formation, but does not depend on crossovers or SC. PMID:12101126

  6. The Paracrinology of Tubal Ectopic Pregnancy

    PubMed Central

    Shaw, Julie L. V.; Horne, Andrew W.

    2011-01-01

    As part of successful human reproduction, the Fallopian tube must provide a suitable environment for pre-implantation development of the embryo and for efficient transport of the embryo to the uterus for implantation. These functions are coordinated by paracrine interactions between tubal epithelial, smooth muscle and immune cells and the cells of the developing embryo. Alterations in these signals can lead to a tubal microenvironment encouraging of embryo implantation and to dysregulated tubal motility, ultimately resulting in inappropriate and early implantation of the embryo in the Fallopian tube. Here, we highlight novel and emerging concepts in tubal physiology and pathobiology, such as the induction of a receptive phenotype within the Fallopian tube, leading to ectopic implantation. Chlamydia trachomatis infection is a risk factor for tubal ectopic pregnancy. Activation of toll-like receptor 2 (TLR-2) in the Fallopian tube epithelium, by C. trachomatis has recently been demonstrated, leading to the dysregulation of factors involved in implantation and smooth muscle contractility, such as prokineticins (PROK), activin A and interleukin 1 (IL-1). The Fallopian tube has also recently been shown to harbour a unique population of immune cells, compared to the endometrium. In addition, the complement of immune cells in the Fallopian tube has been reported to be altered in Fallopian tube from women with ectopic pregnancy. There are increasing data suggesting that vascularisation of the Fallopian tube, by the embryo during ectopic pregnancy, differs from that initiated in the uterus during normal pregnancy. This too, is likely the result of paracrine signals between the embryo and the tubal microenvironment. PMID:21827822

  7. Unilateral duplex horseshoe kidney with ectopic ureterocele

    SciTech Connect

    Sumner, T.E.; Volberg, F.M.; Munitz, A.; Harrison, L.H.; Mashburn, A.M.

    1985-02-01

    Horseshoe kidney results from mesial fusion of the two nephrogenic blastemas during the fourth to seventh weeks of gestation. Associated genitourinary anomalies occur in approximately 25% of patients with horseshoe kidney. The authors report a case of a horseshoe kidney with unilateral pelvis and ureteral duplication with an ectopic ureterocele obstructing its upper moiety diagnosed by intravenous urography and real-time sonography. 13 references, 2 figures.

  8. Ectopic prostatic tissue in the uterine cervix.

    PubMed

    Larraza-Hernandez, O; Molberg, K H; Lindberg, G; Albores-Saavedra, J

    1997-07-01

    This is the first reported case of ectopic prostatic tissue in the uterine cervix, diagnosed in a 38-year-old woman. A cluster of benign prostatic glands with cribriform and papillary patterns and focal squamous metaplasia occupied the superficial endocervical stroma. The glands were immunoreactive for prostatic specific antigen and prostatic specific acid phosphatase. This lesion, which could be confused with microglandular hyperplasia, mesonephric rests, or adenocarcinoma in situ may represent an embryonic rest. PMID:9421098

  9. Normal Segregation of a Foreign-Species Chromosome During Drosophila Female Meiosis Despite Extensive Heterochromatin Divergence

    PubMed Central

    Gilliland, William D.; Colwell, Eileen M.; Osiecki, David M.; Park, Suna; Lin, Deanna; Rathnam, Chandramouli; Barbash, Daniel A.

    2015-01-01

    The abundance and composition of heterochromatin changes rapidly between species and contributes to hybrid incompatibility and reproductive isolation. Heterochromatin differences may also destabilize chromosome segregation and cause meiotic drive, the non-Mendelian segregation of homologous chromosomes. Here we use a range of genetic and cytological assays to examine the meiotic properties of a Drosophila simulans chromosome 4 (sim-IV) introgressed into D. melanogaster. These two species differ by ∼12–13% at synonymous sites and several genes essential for chromosome segregation have experienced recurrent adaptive evolution since their divergence. Furthermore, their chromosome 4s are visibly different due to heterochromatin divergence, including in the AATAT pericentromeric satellite DNA. We find a visible imbalance in the positioning of the two chromosome 4s in sim-IV/mel-IV heterozygote and also replicate this finding with a D. melanogaster 4 containing a heterochromatic deletion. These results demonstrate that heterochromatin abundance can have a visible effect on chromosome positioning during meiosis. Despite this effect, however, we find that sim-IV segregates normally in both diplo and triplo 4 D. melanogaster females and does not experience elevated nondisjunction. We conclude that segregation abnormalities and a high level of meiotic drive are not inevitable byproducts of extensive heterochromatin divergence. Animal chromosomes typically contain large amounts of noncoding repetitive DNA that nevertheless varies widely between species. This variation may potentially induce non-Mendelian transmission of chromosomes. We have examined the meiotic properties and transmission of a highly diverged chromosome 4 from a foreign species within the fruitfly Drosophila melanogaster. This chromosome has substantially less of a simple sequence repeat than does D. melanogaster 4, and we find that this difference results in altered positioning when chromosomes align

  10. Retinoic acid triggers meiosis initiation via stra8-dependent pathway in Southern catfish, Silurus meridionalis.

    PubMed

    Li, Minghui; Feng, Ruijuan; Ma, He; Dong, Ranran; Liu, Zhilong; Jiang, Wentao; Tao, Wenjing; Wang, Deshou

    2016-06-01

    Existing studies demonstrated that retinoic acid (RA) regulates meiotic initiation via stra8-independent pathway in teleosts which lack stra8 in their genomes. However, stra8 was recently identified from several fish species including Southern catfish (Silurus meridionalis). To explore the existence of stra8-dependent pathway in RA mediated meiotic initiation in fishes, in the present study, the genes encoding RA synthase aldh1a2 and catabolic enzyme cyp26a1 and cyp26b1 were cloned from the Southern catfish. By immunohistochemistry, Aldh1a2 signal was observed in gonads of both sexes during the meiotic initiation period. By real-time PCR, differentially expressed gene was observed for cyp26a1, but not for cyp26b1, in gonads during the meiotic initiation. Administration of exogenous RA or inhibition of endogenous RA degradation by either KET (RA catabolic enzyme inhibitor) or cyp26a1 knockdown using CRISPR/Cas9 induced advanced meiotic initiation in the ovaries as demonstrated by increased Stra8/stra8 expression and appearance of oocytes. In contrast, treatment with RA synthase inhibitor DEAB resulted in delayed meiotic initiation and Stra8/stra8 expression in the ovaries, which was rescued by exogenous RA administration. These results indicated that (1) RA triggers the onset of meiosis via stra8-dependent pathway in stra8 existing teleosts, as it does in tetrapods; (2) exogenous RA can rescue the endogenous RA deficiency; (3) Cyp26a1, instead of Cyp26b1, is the key catabolic enzyme involved in meiosis initiation in teleosts. Taken together, RA might trigger meiotic initiation via stra8-dependent and -independent pathway in different teleosts. PMID:26764212

  11. Assembly of RecA-like recombinases: Distinct roles for mediator proteins in mitosis and meiosis

    PubMed Central

    Gasior, Stephen L.; Olivares, Heidi; Ear, Uy; Hari, Danielle M.; Weichselbaum, Ralph; Bishop, Douglas K.

    2001-01-01

    Members of the RecA family of recombinases from bacteriophage T4, Escherichia coli, yeast, and higher eukaryotes function in recombination as higher-order oligomers assembled on tracts of single-strand DNA (ssDNA). Biochemical studies have shown that assembly of recombinase involves accessory factors. These studies have identified a class of proteins, called recombination mediator proteins, that act by promoting assembly of recombinase on ssDNA tracts that are bound by ssDNA-binding protein (ssb). In the absence of mediators, ssb inhibits recombination reactions by competing with recombinase for DNA-binding sites. Here we briefly review mediated recombinase assembly and present results of new in vivo experiments. Immuno-double-staining experiments in Saccharomyces cerevisiae suggest that Rad51, the eukaryotic recombinase, can assemble at or near sites containing ssb (replication protein A, RPA) during the response to DNA damage, consistent with a need for mediator activity. Correspondingly, mediator gene mutants display defects in Rad51 assembly after DNA damage and during meiosis, although the requirements for assembly are distinct in the two cases. In meiosis, both Rad52 and Rad55/57 are required, whereas either Rad52 or Rad55/57 is sufficient to promote assembly of Rad51 in irradiated mitotic cells. Rad52 promotes normal amounts of Rad51 assembly in the absence of Rad55 at 30°C but not 20°C, accounting for the cold sensitivity of rad55 null mutants. Finally, we show that assembly of Rad51 is induced by radiation during S phase but not during G1, consistent with the role of Rad51 in repairing the spontaneous damage that occurs during DNA replication. PMID:11459983

  12. Normal segregation of a foreign-species chromosome during Drosophila female meiosis despite extensive heterochromatin divergence.

    PubMed

    Gilliland, William D; Colwell, Eileen M; Osiecki, David M; Park, Suna; Lin, Deanna; Rathnam, Chandramouli; Barbash, Daniel A

    2015-01-01

    The abundance and composition of heterochromatin changes rapidly between species and contributes to hybrid incompatibility and reproductive isolation. Heterochromatin differences may also destabilize chromosome segregation and cause meiotic drive, the non-Mendelian segregation of homologous chromosomes. Here we use a range of genetic and cytological assays to examine the meiotic properties of a Drosophila simulans chromosome 4 (sim-IV) introgressed into D. melanogaster. These two species differ by ∼12-13% at synonymous sites and several genes essential for chromosome segregation have experienced recurrent adaptive evolution since their divergence. Furthermore, their chromosome 4s are visibly different due to heterochromatin divergence, including in the AATAT pericentromeric satellite DNA. We find a visible imbalance in the positioning of the two chromosome 4s in sim-IV/mel-IV heterozygote and also replicate this finding with a D. melanogaster 4 containing a heterochromatic deletion. These results demonstrate that heterochromatin abundance can have a visible effect on chromosome positioning during meiosis. Despite this effect, however, we find that sim-IV segregates normally in both diplo and triplo 4 D. melanogaster females and does not experience elevated nondisjunction. We conclude that segregation abnormalities and a high level of meiotic drive are not inevitable byproducts of extensive heterochromatin divergence. Animal chromosomes typically contain large amounts of noncoding repetitive DNA that nevertheless varies widely between species. This variation may potentially induce non-Mendelian transmission of chromosomes. We have examined the meiotic properties and transmission of a highly diverged chromosome 4 from a foreign species within the fruitfly Drosophila melanogaster. This chromosome has substantially less of a simple sequence repeat than does D. melanogaster 4, and we find that this difference results in altered positioning when chromosomes align

  13. Understanding a basic biological process: Expert and novice models of meiosis

    NASA Astrophysics Data System (ADS)

    Kindfield, Ann C. H.

    Central to secondary and college-level biology instruction is the development of student understanding of a number of subcellular processes. Yet some of the most crucial are consistently cited as the most difficult components of biology to learn. Among these is meiosis. In this article I report on the meiosis models utilized by five individuals at each of three levels of expertise in genetics as each reasoned about this process in an individual interview setting. Detailed characterization of individual meiosis models and comparison among models revealed a set of biologically correct features common to all individuals' models as well as a variety of model flaws (i.e., meiosis misunderstandings) which are categorized according to type and level of expertise. These results are suggestive of both sources of various misunderstandings and factors that might contribute to the construction of a sound understanding of meiosis. Each of these is addressed in relation to their respective implications for instruction.

  14. Widespread ectopic expression of olfactory receptor genes

    PubMed Central

    Feldmesser, Ester; Olender, Tsviya; Khen, Miriam; Yanai, Itai; Ophir, Ron; Lancet, Doron

    2006-01-01

    Background Olfactory receptors (ORs) are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information. PMID:16716209

  15. Zoonotic ectopic fascioliasis: review and discussion.

    PubMed

    Rashed, Amr A; Khalil, Hazem H M; Morsy, Ayman T A

    2010-12-01

    Ectopic fascioliasis (EF) has direct and indirect effects on both humans and animals. The phenomenon of EF was individual cases in the period from 1950 up to the end of last century. From the period of 2000 up to 2006, plenty of researches were on EF in the developed and undeveloped countries. Nineteen EF cases infected with the immature and few with the mature worms were 13 females and 6 males. Three cases of lymphatic, pleural and breast fascioliasis reached the adults and laid their eggs in a lymph node in the cervical region pleural cavity and breast tissues. Until recent, knowledge about the ectopic fascioliasis pathway is little. Fasciola hepatica was the commonest species in most cases. The effect of fascioliasis might be direct to liver as ectopic foci or indirect on other organs due to the metabolites and secretory excretory products. All ages and both sexes were EF infected. Watercress topped the list of water plants born encysted metacercariae followed by lettuce, mint, and alfalfa. Nearly 24 million Egyptians at risk and about 800,000 were infected. On the global scale, about 180 million are at risk of infection. PMID:21268530

  16. Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions

    PubMed Central

    Gouvêa de Barros, Bruno; Weber dos Santos, Rodrigo; Lobosco, Marcelo; Alonso, Sergio

    2015-01-01

    The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies. PMID:26583127

  17. Whole-mount immunolocalization to study female meiosis in Arabidopsis.

    PubMed

    Escobar-Guzmán, Rocio; Rodríguez-Leal, Daniel; Vielle-Calzada, Jean-Philippe; Ronceret, Arnaud

    2015-10-01

    Here we describe a whole-mount immunolocalization protocol to follow the subcellular localization of proteins during female meiosis in Arabidopsis thaliana, a model species that is used to study sexual reproduction in flowering plants. By using confocal microscopy, the procedure allows one to follow megasporogenesis at all stages before differentiation of the functional megaspore. This in particular includes stages that occur during prophase I, such as the installation of the axial and central elements of the synaptonemal complex along the meiotic chromosomes. In contrast to procedures that require microtome sectioning or enzymatic isolation and smearing to separate female meiocytes from neighboring cells, this 3-day protocol preserves the constitution of the developing primordium and incorporates the architecture of the ovule to provide a temporal and spatial context to meiotic divisions. This opens up the possibility to systematically compare the dynamics of protein localization during female and male meiosis. Steps describe tissue collection and fixation, preparation of slides and polyacrylamide embedding, tissue permeabilization, antibody incubation, propidium iodide staining, and finally image acquisition by confocal microscopy. The procedure adds an essential technique to the toolkit of plant meiotic analysis, and it represents a framework for technical adaptations that could soon allow the analysis of plant reproductive alternatives to sexual reproduction. PMID:26357009

  18. Centromere pairing – tethering partner chromosomes in meiosis I

    PubMed Central

    Kurdzo, Emily L; Dawson, Dean S

    2015-01-01

    In meiosis, homologous chromosomes face the obstacle of finding, holding onto and segregating away from their partner chromosome. There is increasing evidence, in a diverse range of organisms, that centromere–centromere interactions that occur in late prophase are an important mechanism in ensuring segregation fidelity. Centromere pairing appears to initiate when homologous chromosomes synapse in meiotic prophase. Structural proteins of the synaptonemal complex have been shown to help mediate centromere pairing, but how the structure that maintains centromere pairing differs from the structure of the synaptonemal complex along the chromosomal arms remains unknown. When the synaptonemal complex proteins disassemble from the chromosome arms in late prophase, some of these synaptonemal complex components persist at the centromeres. In yeast and Drosophila these centromere-pairing behaviors promote the proper segregation of chromosome partners that have failed to become linked by chiasmata. Recent studies of mouse spermatocytes have described centromere pairing behaviors that are similar in several respects to what has been described in the fly and yeast systems. In humans, chromosomes that fail to experience crossovers in meiosis are error-prone and are a major source of aneuploidy. The finding that centromere pairing is a conserved phenomenon raises the possibility that it may play a role in promoting the segregation fidelity of non-exchange chromosome pairs in humans. PMID:25817724

  19. Meiosis in sesquidiploid hybrids of Lycopersicon esculentum and Solanum lycopersicoides

    PubMed Central

    Rick, Charles M.; De Verna, Joseph W.; Chetelat, Roger T.; Stevens, M. Allen

    1986-01-01

    We have synthesized diploid hybrids between Lycopersicon esculentum and Solanum lycopersicoides and have converted them to allotetraploids. Two sesquidiploids, having two complements of the former parent and one of the latter, have been obtained by backcrossing the former parent with the alloploid. In meiosis of the sesquidiploid the L. esculentum chromosomes exhibit strong preferential pairing, consistently forming 12 bivalents, whereas the S. lycopersicoides chromosomes remain unpaired. This chromosomal comportment conforms with expectations based on meiosis of the 2x and 4x hybrids. Condensation of the S. lycopersicoides univalents is retarded in early diakinesis but their development appears normal at later stages. Presumably as a consequence of the orderly behavior of the L. esculentum bivalents and consequent contribution to each gamete, fertility of the sesquidiploids is higher than in L. esculentum autotriploids. The normally strict self-incompatibility is somewhat relaxed in the sesquidiploids. Extra S. lycopersicoides chromosomes can be transmitted from the sesquidiploid as pistillate parent, and the aneuploid progeny are viable. Establishment of alien addition races and their utilization to transmit desired genes from S. lycopersicoides to L. esculentum are anticipated. Images PMID:16593702

  20. Differential Mitotic Stability of Yeast Disomes Derived from Triploid Meiosis

    PubMed Central

    Campbell, Douglas; Doctor, John S.; Feuersanger, Jeane H.; Doolittle, Mark M.

    1981-01-01

    The frequencies of recovered disomy among the meiotic segregants of yeast (Saccharomyces cerevisiae) triploids were assessed under conditions in which all 17 yeast chromosomes were monitored simultaneously. The studies employed inbred triploids, in which all homologous centromeres were identical by descent, and single haploid testers carrying genetic markers for all 17 linkage groups. The principal results include: (1) Ascospores from triploid meiosis germinate at frequencies comparable to those from normal diploids, but most fail to produce visible colonies due to the growth-retarding effects of high multiple disomy. (2) The probability of disome formation during triploid meiosis is the same for all chromosomes; disomy for any given chromosome does not exclude simultaneous disomy for any other chromosome. (3) The 17 yeast chromosomes fall into three frequency classes in terms of disome recovery. The results support the idea that multiply disomic meiotic segregants of the triploid experience repeated, nonrandom, post-germination mitotic chromosome losses (N+1→N) and that the observed variations in individual disome recovery are wholly attributable to inherent differences in disome mitotic stability. PMID:7035289

  1. Kinetochore-Independent Chromosome Poleward Movement during Anaphase of Meiosis II in Mouse Eggs

    PubMed Central

    Deng, Manqi; Gao, Juntao; Suraneni, Praveen; Li, Rong

    2009-01-01

    Kinetochores are considered to be the key structures that physically connect spindle microtubules to the chromosomes and play an important role in chromosome segregation during mitosis. Due to different mechanisms of spindle assembly between centrosome-containing mitotic cells and acentrosomal meiotic oocytes, it is unclear how a meiotic spindle generates the poleward forces to drive two rounds of meiotic chromosome segregation to achieve genome haploidization. We took advantage of the fact that DNA beads are able to induce bipolar spindle formation without kinetochores and studied the behavior of DNA beads in the induced spindle in mouse eggs during meiosis II. Interestingly, DNA beads underwent poleward movements that were similar in timing and speed to the meiotic chromosomes, although all the beads moved together to the same spindle pole. Disruption of dynein function abolished the poleward movements of DNA beads but not of the meiotic chromosomes, suggesting the existence of different dynein-dependent and dynein-independent force generation mechanisms for the chromosome poleward movement, and the latter may be dependent on the presence of kinetochores. Consistent with the observed DNA bead poleward movement, sperm haploid chromatin (which also induced bipolar spindle formation after injection to a metaphase egg without forming detectable kinetochore structures) also underwent similar poleward movement at anaphase as DNA beads. The results suggest that in the chromatin-induced meiotic spindles, kinetochore attachments to spindle microtubules are not absolutely required for chromatin poleward movements at anaphase. PMID:19365562

  2. Recent advances in understanding of meiosis initiation and the apomictic pathway in plants

    PubMed Central

    Wang, Chung-Ju R.; Tseng, Ching-Chih

    2014-01-01

    Meiosis, a specialized cell division to produce haploid cells, marks the transition from a sporophytic to a gametophytic generation in the life cycle of plants. In angiosperms, meiosis takes place in sporogenous cells that develop de novo from somatic cells in anthers or ovules. A successful transition from the mitotic cycle to the meiotic program in sporogenous cells is crucial for sexual reproduction. By contrast, when meiosis is bypassed or a mitosis-like division occurs to produce unreduced cells, followed by the development of an embryo sac, clonal seeds can be produced by apomixis, an asexual reproduction pathway found in 400 species of flowering plants. An understanding of the regulation of entry into meiosis and molecular mechanisms of apomictic pathway will provide vital insight into reproduction for plant breeding. Recent findings suggest that AM1/SWI1 may be the key gene for entry into meiosis, and increasing evidence has shown that the apomictic pathway is epigenetically controlled. However, the mechanism for the initiation of meiosis during sexual reproduction or for its omission in the apomictic pathway still remains largely unknown. Here we review the current understanding of meiosis initiation and the apomictic pathway and raised several questions that are awaiting further investigation. PMID:25295051

  3. Recent advances in understanding of meiosis initiation and the apomictic pathway in plants.

    PubMed

    Wang, Chung-Ju R; Tseng, Ching-Chih

    2014-01-01

    Meiosis, a specialized cell division to produce haploid cells, marks the transition from a sporophytic to a gametophytic generation in the life cycle of plants. In angiosperms, meiosis takes place in sporogenous cells that develop de novo from somatic cells in anthers or ovules. A successful transition from the mitotic cycle to the meiotic program in sporogenous cells is crucial for sexual reproduction. By contrast, when meiosis is bypassed or a mitosis-like division occurs to produce unreduced cells, followed by the development of an embryo sac, clonal seeds can be produced by apomixis, an asexual reproduction pathway found in 400 species of flowering plants. An understanding of the regulation of entry into meiosis and molecular mechanisms of apomictic pathway will provide vital insight into reproduction for plant breeding. Recent findings suggest that AM1/SWI1 may be the key gene for entry into meiosis, and increasing evidence has shown that the apomictic pathway is epigenetically controlled. However, the mechanism for the initiation of meiosis during sexual reproduction or for its omission in the apomictic pathway still remains largely unknown. Here we review the current understanding of meiosis initiation and the apomictic pathway and raised several questions that are awaiting further investigation. PMID:25295051

  4. Abortive second meiosis detected in cytochalasin-treated eggs in androgenetic diploid Corbicula fluminea.

    PubMed

    Ishibashi, Ryo; Komaru, Akira

    2006-05-01

    The hermaphroditic diploid clam Corbicula fluminea reproduces by androgenesis. In the control (androgenetic development), all maternal chromosomes and maternal centrosomes at the meiotic poles were extruded as two first polar bodies and subsequently second meiosis did not occur. In eggs treated with cytochalasin D (CD) to inhibit the polar body extrusion, the second meiosis was abortive. After the first meiosis, two centrosomes at the spindle poles remained in the cytoplasm because of the effect of CD. The chromosomes divided into two groups at anaphase-I as observed in the control eggs. Two centrosomes divided into four just after the first meiosis but did not separate completely. The microtubules from the centrosomes were rather short. So at the second meiosis, two monoasters or tetrapolar spindles were formed. The fluorescence signal from microtubules of the monoaster or tetrapolar spindle was weak compared with the spindle at the first meiosis. The maternal chromosomes on the monoaster or tetrapolar spindle did not move, and became large female pronuclei. The pronuclei became the metaphase chromosomes on the spindle for the first cleavage. The present study suggests that second meiosis regulating factors may be abortive in androgenetic diploid C. fluminea. PMID:16681653

  5. [Ectopic parathyroid glands. Imaging methods and surgical access].

    PubMed

    Fialová, M; Adámková, J; Adámek, S; Libánský, P; Kubinyi, J

    2014-08-01

    We discuss the benefits of imaging methods in localizing ectopic parathyroid glands in patients with primary hyperparathyroidism. The ectopic localizations are discussed within the context of the orthotopic norm. In the sample of 123 patients, a 23% rate of ectopic parathyroid glands was detected. Three selected case studies are presented, supporting the benefit of SPECT/CT imaging in terms of surgical access strategy selection. PMID:25230388

  6. [Ectopic internal carotid artery of the oropharynx: two cases report].

    PubMed

    Xie, Sanlin; Chen, Shiyan; Chen, Xianming

    2016-02-01

    Ectopic internal carotid artery (ICA) is a very rare congenital variation. Unless the diagnosis is made before neck or tonsil surgery, massive hemorrhage and even death may result from injury to the vessel. Therefore, knowledge of the presence of ectopic ICAs may be important. We report two cases suffering from dysphagia associated with ectopic ICA manifesting itself as a pulsative protruding of the right lateral wall of the oropharynx. PMID:27373046

  7. Recurrent Ectopic Pregnancy in the Tubal Remnant after Salpingectomy

    PubMed Central

    Samiei-Sarir, Bahareh; Diehm, Christopher

    2013-01-01

    We present two cases of ectopic pregnancy located within the remnant tube following ipsilateral salpingectomy. This particular pathology is rare and yet has significant consequences for the patient, with mortality rates 10–15 times higher than other ectopic pregnancies. It demonstrates that salpingectomy does not exclude ectopic pregnancy on the ipsilateral side. We suggest careful clinical consideration and bring attention to the current surgical technique. PMID:24151570

  8. Ectopic Expression of WRINKLED1 Affects Fatty Acid Homeostasis in Brachypodium distachyon Vegetative Tissues1[OPEN

    PubMed Central

    Yang, Yang; Munz, Jacob; Cass, Cynthia; Zienkiewicz, Agnieszka; Kong, Que; Ma, Wei; Sedbrook, John; Benning, Christoph

    2015-01-01

    Triacylglycerol (TAG) is a storage lipid used for food purposes and as a renewable feedstock for biodiesel production. WRINKLED1 (WRI1) is a transcription factor that governs fatty acid (FA) synthesis and, indirectly, TAG accumulation in oil-storing plant tissues, and its ectopic expression has led to TAG accumulation in vegetative tissues of different dicotyledonous plants. The ectopic expression of BdWRI1 in the grass Brachypodium distachyon induced the transcription of predicted genes involved in glycolysis and FA biosynthesis, and TAG content was increased up to 32.5-fold in 8-week-old leaf blades. However, the ectopic expression of BdWRI1 also caused cell death in leaves, which has not been observed previously in dicotyledonous plants such as Arabidopsis (Arabidopsis thaliana). Lipid analysis indicated that the free FA content was 2-fold elevated in BdWRI1-expressing leaf blades of B. distachyon. The transcription of predicted genes involved in β-oxidation was induced. In addition, linoleic FA treatment caused cell death in B. distachyon leaf blades, an effect that was reversed by the addition of the FA biosynthesis inhibitor cerulenin. Taken together, ectopic expression of BdWRI1 in B. distachyon enhances FA biosynthesis and TAG accumulation in leaves, as expected, but also leads to increased free FA content, which has cytotoxic effects leading to cell death. Thus, while WRI appears to ubiquitously affect FA biosynthesis and TAG accumulation in diverse plants, its ectopic expression can lead to undesired side effects depending on the context of the specific lipid metabolism of the respective plant species. PMID:26419778

  9. Ectopic Expression of WRINKLED1 Affects Fatty Acid Homeostasis in Brachypodium distachyon Vegetative Tissues.

    PubMed

    Yang, Yang; Munz, Jacob; Cass, Cynthia; Zienkiewicz, Agnieszka; Kong, Que; Ma, Wei; Sedbrook, John; Benning, Christoph

    2015-11-01

    Triacylglycerol (TAG) is a storage lipid used for food purposes and as a renewable feedstock for biodiesel production. WRINKLED1 (WRI1) is a transcription factor that governs fatty acid (FA) synthesis and, indirectly, TAG accumulation in oil-storing plant tissues, and its ectopic expression has led to TAG accumulation in vegetative tissues of different dicotyledonous plants. The ectopic expression of BdWRI1 in the grass Brachypodium distachyon induced the transcription of predicted genes involved in glycolysis and FA biosynthesis, and TAG content was increased up to 32.5-fold in 8-week-old leaf blades. However, the ectopic expression of BdWRI1 also caused cell death in leaves, which has not been observed previously in dicotyledonous plants such as Arabidopsis (Arabidopsis thaliana). Lipid analysis indicated that the free FA content was 2-fold elevated in BdWRI1-expressing leaf blades of B. distachyon. The transcription of predicted genes involved in β-oxidation was induced. In addition, linoleic FA treatment caused cell death in B. distachyon leaf blades, an effect that was reversed by the addition of the FA biosynthesis inhibitor cerulenin. Taken together, ectopic expression of BdWRI1 in B. distachyon enhances FA biosynthesis and TAG accumulation in leaves, as expected, but also leads to increased free FA content, which has cytotoxic effects leading to cell death. Thus, while WRI appears to ubiquitously affect FA biosynthesis and TAG accumulation in diverse plants, its ectopic expression can lead to undesired side effects depending on the context of the specific lipid metabolism of the respective plant species. PMID:26419778

  10. Disruption of myelin leads to ectopic expression of K(V)1.1 channels with abnormal conductivity of optic nerve axons in a cuprizone-induced model of demyelination.

    PubMed

    Bagchi, Bandita; Al-Sabi, Ahmed; Kaza, Seshu; Scholz, Dimitri; O'Leary, Valerie B; Dolly, J Oliver; Ovsepian, Saak V

    2014-01-01

    The molecular determinants of abnormal propagation of action potentials along axons and ectopic conductance in demyelinating diseases of the central nervous system, like multiple sclerosis (MS), are poorly defined. Widespread interruption of myelin occurs in several mouse models of demyelination, rendering them useful for research. Herein, considerable myelin loss is shown in the optic nerves of cuprizone-treated demyelinating mice. Immuno-fluorescence confocal analysis of the expression and distribution of voltage-activated K⁺ channels (K(V)1.1 and 1.2 α subunits) revealed their spread from typical juxta-paranodal (JXP) sites to nodes in demyelinated axons, albeit with a disproportionate increase in the level of K(V)1.1 subunit. Functionally, in contrast to monophasic compound action potentials (CAPs) recorded in controls, responses derived from optic nerves of cuprizone-treated mice displayed initial synchronous waveform followed by a dispersed component. Partial restoration of CAPs by broad spectrum (4-aminopyridine) or K(V)1.1-subunit selective (dendrotoxin K) blockers of K⁺ currents suggest enhanced K(V)1.1-mediated conductance in the demyelinated optic nerve. Biophysical profiling of K⁺ currents mediated by recombinant channels comprised of different K(V)1.1 and 1.2 stoichiometries revealed that the enrichment of K(V)1 channels K(V)1.1 subunit endows a decrease in the voltage threshold and accelerates the activation kinetics. Together with the morphometric data, these findings provide important clues to a molecular basis for temporal dispersion of CAPs and reduced excitability of demyelinated optic nerves, which could be of potential relevance to the patho-physiology of MS and related disorders. PMID:24498366

  11. [Cushing syndrome due to ectopic ACTH secretion].

    PubMed

    Mendonça, B B; Madureira, G; Bloise, W; Albergaria, A; Halpern, A; Liberman, B; Villares, S M; Batista, M C; Avancini, V F; Nitterdorfi, C T

    1989-01-01

    The authors studied 8 patients (4 males and 4 females) with Cushing's syndrome due to ectopic ACTH secretion. Chronological age ranged from 15 to 45 years and duration of the disease ranged from 3 to 48 months. All patients presented typical signs of Cushing's syndrome, blood hypertension, and four of them had hyperpigmentation of the skin. Five patients had fasting hyperglycemia and all patients but one had serum hypokalemia (serum K = 2.2 to 3.9mEq/l). The circadian rhythm of cortisol was absent in all patients and basal cortisol levels were elevated in all patients but one. Basal ACTH levels evaluated in 7 patients were elevated in 6 (29 to 1050 pg/ml-MRC). One patient presented normal depression of urinary 17-OH after two days of dexamethasone and normal increase of urinary 17-OH and serum 11-dexycortisol after methyrapone. Four patients had carcinoid tumor (3 thymic and 1 bronchial), two had pancreatic islets cell tumors, one had bilateral pheochromocytoma and medular carcinoma of the thyroid, and one had oat cell carcinoma of the lung and medular carcinoma of the thyroid. Thoracic X-rays identified the ectopic ACTH secretion tumor in four cases, all confirmed by CT scan. Abdominal CT showed a difuse enlargement of the adrenals in seven cases and bilateral nodules in one case (pheochromocytomas). Six patients died within 3 years of the diagnosis. The authors concluded that clinical and hormonal findings could mislead the findings of ACTH ectopic secretion and Cushing's disease, and suggest that thoracic X-rays and CT scans of the skull, thorax, and abdome should be done in all cases of Cushing's syndrome. PMID:2559451

  12. Current knowledge of the aetiology of human tubal ectopic pregnancy

    PubMed Central

    Shaw, J.L.V.; Dey, S.K.; Critchley, H.O.D.; Horne, A.W.

    2010-01-01

    BACKGROUND An ectopic pregnancy is a pregnancy which occurs outside of the uterine cavity, and over 98% implant in the Fallopian tube. Tubal ectopic pregnancy remains the most common cause of maternal mortality in the first trimester of pregnancy. The epidemiological risk factors for tubal ectopic pregnancy are well established and include: tubal damage as a result of surgery or infection (particularly Chlamydia trachomatis), smoking and in vitro fertilization. This review appraises the data to date researching the aetiology of tubal ectopic pregnancy. METHODS Scientific literature was searched for studies investigating the underlying aetiology of tubal ectopic pregnancy. RESULTS Existing data addressing the underlying cause of tubal ectopic pregnancy are mostly descriptive. There are currently few good animal models of tubal ectopic pregnancy. There are limited data explaining the link between risk factors and tubal implantation. CONCLUSIONS Current evidence supports the hypothesis that tubal ectopic pregnancy is caused by a combination of retention of the embryo within the Fallopian tube due to impaired embryo-tubal transport and alterations in the tubal environment allowing early implantation to occur. Future studies are needed that address the functional consequences of infection and smoking on Fallopian tube physiology. A greater understanding of the aetiology of tubal ectopic pregnancy is critical for the development of improved preventative measures, the advancement of diagnostic screening methods and the development of novel treatments. PMID:20071358

  13. Ectopic goitrous submandibular thyroid with goitrous orthotopic thyroid gland.

    PubMed

    Bhardwaj, Avinash Kumar; Mani, Vinayaga; Dixit, Rashmi; Garg, Anju

    2016-01-01

    Ectopic thyroid is a rare developmental anomaly with lingual thyroid accounting for majority of the cases. The presence of ectopic thyroid tissue lateral to the midline is very rare, and very few cases located in the submandibular region have been reported. The simultaneous finding of submandibular ectopic thyroid tissue and a functional orthotopic thyroid gland is even rarer. In the differential diagnosis of an ectopic submandibular thyroid, it is fundamental to exclude a metastasis from well-differentiated thyroid cancer, even when primary thyroid carcinoma is not demonstrable. PMID:27413274

  14. Ectopic goitrous submandibular thyroid with goitrous orthotopic thyroid gland

    PubMed Central

    Bhardwaj, Avinash Kumar; Mani, Vinayaga; Dixit, Rashmi; Garg, Anju

    2016-01-01

    Ectopic thyroid is a rare developmental anomaly with lingual thyroid accounting for majority of the cases. The presence of ectopic thyroid tissue lateral to the midline is very rare, and very few cases located in the submandibular region have been reported. The simultaneous finding of submandibular ectopic thyroid tissue and a functional orthotopic thyroid gland is even rarer. In the differential diagnosis of an ectopic submandibular thyroid, it is fundamental to exclude a metastasis from well-differentiated thyroid cancer, even when primary thyroid carcinoma is not demonstrable. PMID:27413274

  15. Ectopic activity in the rat pulmonary vein can arise from simultaneous activation of α1- and β1-adrenoceptors

    PubMed Central

    Maupoil, V; Bronquard, C; Freslon, J-L; Cosnay, P; Findlay, I

    2007-01-01

    Background and purpose: Atrial fibrillation (AF) is the most common electrical cardiac disorder in clinical practice. The major trigger for AF is focal ectopic activity of unknown origin in sleeves of cardiac muscle that extend into the pulmonary veins. We examined the role of noradrenaline in the genesis of ectopic activity in the pulmonary vein. Experimental approach: Mechanical activity of strips of pulmonary vein isolated from male Wistar rats was recorded via an isometric tension meter. Twitch contractions of cardiac myocytes were evoked by electrical field stimulation in a tissue bath through which flowed Krebs-Heinseleit solution warmed to 36-37°C and gassed with 95% O2 5% CO2. Key results: The superfusion of noradrenaline induced ectopic contractions in 71 of 76 different isolated pulmonary veins. Ectopic contractions in the pulmonary vein were not associated with electrically evoked twitch contractions. The effect of noradrenaline on the pulmonary vein could be replicated by the simultaneous, but not separate, application of the α adrenoceptor agonist phenylephrine and the β adrenoceptor agonist isoprenaline. The use of selective agonists and antagonists for adrenoceptor subtypes showed that ectopic activity in the pulmonary vein arose from the simultaneous stimulation of α1 and β1 adrenoceptors. The application of noradrenaline to isolated strips of left atrium did not induce ectopic contractions (n=10). Conclusions: These findings suggest an origin for ectopic activity in the pulmonary vein that requires activation of both α and β adrenoceptors. They also open new perspectives towards our understanding of the triggering of AF. PMID:17325650

  16. Treatment of ectopic pregnancy with methotrexate.

    PubMed

    Kasum, Miro; Oresković, Slavko; Simunić, Velimir; Jezek, Davor; Tomić, Vlatka; Tomić, Jozo; Gall, Vesna; Mihaljević, Slobodan

    2012-12-01

    The aim of the present study was to analyze retrospectively the safety and success rates of single- and two-dose methotrexate (MTX) protocols for the treatment of hemodynamically stable cases of ectopic pregnancy at University Department of Gynecology and Obstetrics, Zagreb University Hospital Center, during a five-year period. The study evaluated MTX treatment efficacy in 35 women with ectopic pregnancies in relation to the initial levels of human chorionic gonadotropin (hCG) and progesterone. Successful treatment was recorded in 32/35 women, 24/25 on single dose MTX and 8/10 on double dose MTX, whereas 3/35 patients underwent laparoscopy. The mean initial hCG level in all 35 patients on day 0 was 657.54 +/- 592.4 IU/L; 572.99 +/- 488.10 IU/L in those successfully treated with MTX and 1560.30 +/- 890.70 IU/L in those requiring additional laparoscopy (p < 0.005). The mean initial hCG level was 393.10 +/- 305.9 IU/L in patients successfully treated with a single dose of MTX and 973.5 +/- 722.40 IU/L in those with an additional dose of MTX (p < 0.002). The mean initial progesterone level was 16.36 +/-10.70 nmol/L in 35 MTX-treated ectopic pregnancy patients, 13.64 +/- 8.89 nmol/L in those with treatment success and 28.45 +/- 11.32 nmol/L in cases of treatment failure (p < 0.05). The mean level of progesterone on day 0 was 12.74 +/- 830 nmol/L in patients successfully treated with a single dose of MTX and 26.10 +/- 18.80 nmol/L in patients treated with double-dose MTX (p < 0.006). It is concluded that pretreatment values of hCG and progesterone are inversely related to medicamentous treatment success in selected cases ofhemodynamically stable patients, thus they may be used as an important predictor in the management of ectopic pregnancy treated with MTX. PMID:23540161

  17. [Update on Current Care Guidelines: Ectopic pregnancy].

    PubMed

    Mäkinen, Juha; Töyli, Mira; Niemimaa, Marko; Kulju, Pekka; Sokka, Tarja; Vuorela, Piia

    2015-01-01

    Ectopic pregnancy should be suspected it a woman of fertile age has lower abdominal pain and irregular vaginal bleeding. Symptoms range from almost none to shock. The diagnosis is based on a quantitative serum pregnancy test (hCG) and transvaginal ultrasound. An acute situation requires emergency surgery, whereas patients with mild symptoms should be treated policlinically by follow-up or a single intramuscular dose (1 mg/kg) of methotrexate. No folic acid supplementation is needed. In later pregnancies their location should be verified by transvaginal ultrasound done by the seventh gestational week at the latest. PMID:26245062

  18. Aurora kinase A controls meiosis I progression in mouse oocytes

    PubMed Central

    Saskova, Adela; Solc, Petr; Baran, Vladimir; Kubelka, Michal; Schultz, Richard M.; Motlik, Jan

    2011-01-01

    Aurora kinase A (AURKA), which is a centrosome-localized serine/threonine kinase crucial for cell cycle control, is critically involved in centrosome maturation and spindle assembly in somatic cells. Active T288 phosphorylated AURKA localizes to the centrosome in the late G2 and also spreads to the minus ends of mitotic spindle microtubules. AURKA activates centrosomal CDC25B and recruits cyclin B1 to centrosomes. We report here functions for AURKA in meiotic maturation of mouse oocytes, which is a model system to study the G2 to M transition. Whereas AURKA is present throughout the entire GV-stage oocyte with a clear accumulation on microtubule organizing centers (MTOC), active AURKA becomes entirely localized to MTOCs shortly before germinal vesicle breakdown. In contrast to somatic cells in which active AURKA is present at the centrosomes and minus ends of microtubules, active AURKA is mainly located on MTOCs at metaphase I (MI) in oocytes. Inhibitor studies using Roscovitine (CDK1 inhibitor), LY-294002 (PI3K inhibitor) and SH-6 (PKB inhibitor) reveal that activation of AURKA localized on MTOCs is independent on PI3K-PKB and CDK1 signaling pathways and MOTC amplification is observed in roscovitine- and SH-6-treated oocytes that fail to undergo nuclear envelope breakdown. Moreover, microinjection of Aurka mRNA into GV-stage oocytes cultured in 3-isobutyl-1-methyl xanthine (IBMX)-containing medium to prevent maturation also results in MOTC amplification in the absence of CDK1 activation. Overexpression of AURKA also leads to formation of an abnormal MI spindle, whereas RNAi-mediated reduction of AURKA interferes with resumption of meiosis and spindle assembly. Results of these experiments indicate that AURKA is a critical MTOC-associated component involved in resumption of meiosis, MTOC multiplication, proper spindle formation and the metaphase I-metaphase II transition. PMID:18677115

  19. Cushing's syndrome due to ectopic ACTH secretion.

    PubMed

    Cieszyński, Łukasz; Berendt-Obołończyk, Monika; Szulc, Michał; Sworczak, Krzysztof

    2016-01-01

    Cushing's syndrome (CS) is defined as a constellation of clinical signs and symptoms occurring due to hypercortisolism. Cortisol excess may be endogenous or exogenous. The most common cause of CS is glucocorticoid therapy with supraphysiological (higher than in the case of substitution) doses used in various diseases (e.g. autoimmune). One possible CS cause is ectopic (extra-pituitary) ACTH secretion (EAS) by benign or malignant tumours. Since its first description in 1963, EAS aetiology has changed, i.e. as well as small cell lung cancer (SCLC), higher incidence in other malignancies has been reported. Ectopic ACTH secretion symptoms are usually similar to hypercortisolism symptoms due to other causes. A clinical suspicion of CS requires laboratory investigations. There is no single and specific laboratory test for making a CS diagnosis, and therefore multiple dynamic tests should be ordered. A combination of multiple laboratory noninvasive and invasive tests gives 100% sensitivity and 98% specificity for EAS diagnosis. If the EAS is caused by localised malignancy, surgery is the optimal treatment choice. Radical tumour excision may be performed in 40% of patients, and 80% of them are cured of the disease. The authors present an interesting clinical case of EAS, which is always a huge diagnostic challenge for clinicians. (Endokrynol Pol 2016; 67 (4): 458-464). PMID:27387249

  20. Meiosis I in Xenopus oocytes is not error-prone despite lacking spindle assembly checkpoint.

    PubMed

    Liu, Dandan; Shao, Hua; Wang, Hongmei; Liu, X Johné

    2014-01-01

    The spindle assembly checkpoint, SAC, is a surveillance mechanism to control the onset of anaphase during cell division. SAC prevents anaphase initiation until all chromosome pairs have achieved bipolar attachment and aligned at the metaphase plate of the spindle. In doing so, SAC is thought to be the key mechanism to prevent chromosome nondisjunction in mitosis and meiosis. We have recently demonstrated that Xenopus oocyte meiosis lacks SAC control. This prompted the question of whether Xenopus oocyte meiosis is particularly error-prone. In this study, we have karyotyped a total of 313 Xenopus eggs following in vitro oocyte maturation. We found no hyperploid egg, out of 204 metaphase II eggs with countable chromosome spreads. Therefore, chromosome nondisjunction is very rare during Xenopus oocyte meiosis I, despite the lack of SAC. PMID:24646611

  1. Ectopic expression of interferon regulatory factor-1 potentiates granulocytic differentiation.

    PubMed Central

    Coccia, E M; Stellacci, E; Valtieri, M; Masella, B; Feccia, T; Marziali, G; Hiscott, J; Testa, U; Peschle, C; Battistini, A

    2001-01-01

    Numerous transcription factors allow haematopoietic cells to respond to lineage- and stage-specific cytokines and to act as their effectors. It is increasingly evident that the interferon regulatory factor-1 (IRF-1) transcription factor can selectively regulate different sets of genes depending on the cell type and/or the nature of cellular stimuli, evoking distinct responses in each. In the present study, we investigated mechanisms underlying the differentiation-inducing properties of granulocytic colony-stimulating factor (G-CSF) and whether IRF transcription factors are functionally relevant in myeloid differentiation. Both normal human progenitors and murine 32Dcl3 myeloblasts induced to differentiate along the granulocytic pathway showed an up-regulation of IRF-1 expression. Ectopic expression of IRF-1 did not abrogate the growth factor requirement of 32Dcl3 cells, although a small percentage of cells that survived cytokine deprivation differentiated fully to neutrophils. Moreover, in the presence of G-CSF, granulocytic differentiation of IRF-1-expressing cells was accelerated, as assessed by morphology and expression of specific differentiation markers. Down-modulation of c-Myb protein and direct stimulation of lysozyme promoter activity by IRF-1 were also observed. Conversely, constitutive expression of IRF-2, a repressor of IRF-1 transcriptional activity, completely abrogated the G-CSF-induced neutrophilic maturation. We conclude that IRF-1 exerts a pivotal role in granulocytic differentiation and that its induction by G-CSF represents a limiting step in the early events of differentiation. PMID:11716756

  2. Ectopic Pancreas in the Wall of the Small Intestine.

    PubMed

    Serrano, Jose Salvador; Stauffer, John A

    2016-07-01

    Ectopic pancreas is an uncommon and benign finding. However, these lesions can cause symptoms including abdominal pain and often require removal. We present the case of a 27-year-old patient with long-standing vague abdominal symptoms eventually found to have ectopic pancreas tissue in the proximal jejunum. PMID:26892166

  3. Laparoscopic management of three rare types of ectopic pregnancy.

    PubMed

    Yan, C M

    2010-04-01

    The laparoscopic management of three rare types of ectopic pregnancy, including rudimentary horn pregnancy, caesarean scar pregnancy, and interstitial pregnancy is described. All were managed with little morbidity. When the appropriate facilities and skills are available, laparoscopic surgery is the surgical treatment of choice for the various types of ectopic pregnancy. PMID:20354248

  4. Inhibition of the Smc5/6 Complex during Meiosis Perturbs Joint Molecule Formation and Resolution without Significantly Changing Crossover or Non-crossover Levels

    PubMed Central

    Lilienthal, Ingrid; Kanno, Takaharu; Sjögren, Camilla

    2013-01-01

    Meiosis is a specialized cell division used by diploid organisms to form haploid gametes for sexual reproduction. Central to this reductive division is repair of endogenous DNA double-strand breaks (DSBs) induced by the meiosis-specific enzyme Spo11. These DSBs are repaired in a process called homologous recombination using the sister chromatid or the homologous chromosome as a repair template, with the homolog being the preferred substrate during meiosis. Specific products of inter-homolog recombination, called crossovers, are essential for proper homolog segregation at the first meiotic nuclear division in budding yeast and mice. This study identifies an essential role for the conserved Structural Maintenance of Chromosomes (SMC) 5/6 protein complex during meiotic recombination in budding yeast. Meiosis-specific smc5/6 mutants experience a block in DNA segregation without hindering meiotic progression. Establishment and removal of meiotic sister chromatid cohesin are independent of functional Smc6 protein. smc6 mutants also have normal levels of DSB formation and repair. Eliminating DSBs rescues the segregation block in smc5/6 mutants, suggesting that the complex has a function during meiotic recombination. Accordingly, smc6 mutants accumulate high levels of recombination intermediates in the form of joint molecules. Many of these joint molecules are formed between sister chromatids, which is not normally observed in wild-type cells. The normal formation of crossovers in smc6 mutants supports the notion that mainly inter-sister joint molecule resolution is impaired. In addition, return-to-function studies indicate that the Smc5/6 complex performs its most important functions during joint molecule resolution without influencing crossover formation. These results suggest that the Smc5/6 complex aids primarily in the resolution of joint molecules formed outside of canonical inter-homolog pathways. PMID:24244180

  5. Genetic control of recombination partner preference in yeast meiosis. Isolation and characterization of mutants elevated for meiotic unequal sister-chromatid recombination.

    PubMed Central

    Thompson, D A; Stahl, F W

    1999-01-01

    Meiotic exchange occurs preferentially between homologous chromatids, in contrast to mitotic recombination, which occurs primarily between sister chromatids. To identify functions that direct meiotic recombination events to homologues, we screened for mutants exhibiting an increase in meiotic unequal sister-chromatid recombination (SCR). The msc (meiotic sister-chromatid recombination) mutants were quantified in spo13 meiosis with respect to meiotic unequal SCR frequency, disome segregation pattern, sporulation frequency, and spore viability. Analysis of the msc mutants according to these criteria defines three classes. Mutants with a class I phenotype identified new alleles of the meiosis-specific genes RED1 and MEK1, the DNA damage checkpoint genes RAD24 and MEC3, and a previously unknown gene, MSC6. The genes RED1, MEK1, RAD24, RAD17, and MEC1 are required for meiotic prophase arrest induced by a dmc1 mutation, which defines a meiotic recombination checkpoint. Meiotic unequal SCR was also elevated in a rad17 mutant. Our observation that meiotic unequal SCR is elevated in meiotic recombination checkpoint mutants suggests that, in addition to their proposed monitoring function, these checkpoint genes function to direct meiotic recombination events to homologues. The mutants in class II, including a dmc1 mutant, confer a dominant meiotic lethal phenotype in diploid SPO13 meiosis in our strain background, and they identify alleles of UBR1, INP52, BUD3, PET122, ELA1, and MSC1-MSC3. These results suggest that DMC1 functions to bias the repair of meiosis-specific double-strand breaks to homologues. We hypothesize that the genes identified by the class II mutants function in or are regulators of the DMC1-promoted interhomologue recombination pathway. Class III mutants may be elevated for rates of both SCR and homologue exchange. PMID:10511544

  6. The value of sonography in suspected ectopic pregnancy.

    PubMed

    Kelly, M T; Santos-Ramos, R; Duenhoelter, J H

    1979-06-01

    Of 356 women undergoing sonography to diagnose or rule out an ectopic gestation, data sufficient to assign a final diagnosis were available on 260 of them. Ectopic gestation was diagnosed in 25 cases in this group and intrauterine pregnancy in 99, while the remaining 136 patients were found not to be pregnant. During sonography, ectopic gestations were suspected or diagnosed in 27 instances: In 17 cases this was in agreement with the final diagnosis, but neither an intrauterine nor an extrauterine gestation existed in 10 cases, although neoplastic or inflammatory masses were present. Of the 25 patients with the final diagnosis "ectopic pregnancy," this was not detected with sonography in 8 instances. Intrauterine pregnancies were diagnosed by sonar in 94 of the 99 cases. Although reliable sonar identification of ectopic gestation is not always possible, sonography is helpful in diagnosing intrauterine pregnancy so that surgical intervention can be avoided. PMID:450337

  7. Radionuclide Imaging of Dual Ectopic Thyroid in a Preadolescent Girl

    PubMed Central

    Yıldırım, Şule; Atılgan, Hasan İkbal; Korkmaz, Meliha; Demirel, Koray; Koca, Gökhan

    2014-01-01

    Ectopic thyroid is a congenital defect in which the thyroid gland is located away from the usual pretracheal location. Dual ectopic thyroid, which consists of two foci of thyroid tissue, is very rare. In this case dual ectopic thyroid with subclinical hypothyroidism in a 10-year-old-girl was reported. The absence of the thyroid gland in the pretracheal location was revealed by ultrasonography (USG). Two foci of ectopic thyroid tissue located at the base of the tongue and infrahyoid region were determined by Technetium-99m pertechnetate thyroid scintigraphy. It can be concluded that if the thyroid gland is not visible by USG, ectopic thyroid tissue should be evaluated with scintigraphy. PMID:25541934

  8. [Thymic carcinoid associated with ectopic ACTH syndrome].

    PubMed

    Ishikawa, T; Inoue, C; Sasaki, H; Satou, K; Kimura, N

    1996-04-01

    A 63-year-old man was admitted to Sendai Red Cross Hospital complaining of chest and back pain associated with Cushing's syndrome. Based on the abnormally high levels of ACTH, cortisol, and CRH in plasma the patient was suspected of having ectopic ACTH syndrome. Histological examination of an extirpated rib and pleural tumor led to the diagnosis of atypical carcinoid tumor, with ribbon and festoon formation, immunoreactivity to ACTH, NSE, Chg-A, and argyrophilia in the tumor cells. Anti-cancer chemotherapy was not effective, and the patient died within a year after the onset of Cushing's syndrome. An autopsy revealed that the patient had an ACTH- and CRH-producing thymic carcinoid with metastases to many organs. The pituitary was atrophic with Crooke's hyaline change. There were many CRH-positive cells in the paraventricular nuclei of the hypothalamus, where no remarkable pathologic changes were seen. PMID:8691671

  9. The orthodontic management of ectopic canine

    PubMed Central

    Thirunavukkarasu, R.; Sriram, G.; Satish, R.

    2015-01-01

    The canines being the cornerstone of the arch and smile is one of the teeth, which has the longest eruption passage that gets influenced by local and general etiological factors easily. The initial calcification of the crowns starts at 4–5 months of age and proceeds toward eruption about 11–13 years of age with mesiobuccal crown angulation that gets corrected toward occlusion. It gets displaced buccally or palatally or may sometimes get impacted. Early intervention is the best suited to manage canine eruption patterns. Once erupted ectopically, they possess a great challenge in repositioning them back into their correct position. This case report discusses an orthodontic treatment planning and execution to correct a buccally placed canine with an anterior crossbite in an adult. PMID:26538959

  10. Ectopic osteochondral formation of biomimetic porous PVA-n-HA/PA6 bilayered scaffold and BMSCs construct in rabbit.

    PubMed

    Qu, Dan; Li, Jihua; Li, Yubao; Khadka, Ashish; Zuo, Yi; Wang, Hang; Liu, Yiming; Cheng, Lin

    2011-01-01

    In this work, the novel poly vinyl alcohol/gelatin-nano-hydroxyapatite/polyamide6 (PVA-n-HA/PA6) bilayered scaffold with biomimetic properties for articular cartilage and subchondral bone is developed. Furthermore, when these osteochondral scaffolds were seeded with induced bone mesenchymal stem cells (BMSCs) and implanted at ectopic sites, showed the potential for an engineered cartilage tissue and the corresponding subchondral bone. BMSCs were expanded in vitro and induced to chondrogenic or osteogenic potential by culturing in suitable media for 14 days. Subsequently, these induced cells were seeded into PVA-n-HA/PA6 separately, and the constructs were implanted into the rabbit muscle pouch for upto 12 weeks. Ectopic neocartilage formation in the PVA layer and reconstitution of the subchondral bone which remained confined within the n-HA/PA6 layer with the alteration of the cellular phenotype were identified with Masson's trichrome stain. Simultaneously, the RT-PCR results confirmed the expression of specific extracellular matrix (ECM) markers for cartilaginous tissue, such as collagen type II (Col-II), or alternatively, markers for osteoid tissue, such as collagen type I (Col-I) at the corresponding layers. During ectopic implantation, the underlying subchondral bone layer was completely integrated with the cartilage layer. The result from the ectopic osteochondral scaffolds implantation suggests that PVA-n-HA/PA6 with induced BMSCs is a possible substitute with potential in cartilage repair strategies. PMID:20967773