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Sample records for chromosome inactivation drives

  1. Female meiotic sex chromosome inactivation in chicken.

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    Sam Schoenmakers

    2009-05-01

    Full Text Available During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW, whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

  2. Chromosomal rearrangement interferes with meiotic X chromosome inactivation

    Czech Academy of Sciences Publication Activity Database

    Homolka, David; Ivánek, Robert; Čapková, Jana; Jansa, Petr; Forejt, Jiří

    2007-01-01

    Roč. 17, č. 10 (2007), s. 1431-1437 ISSN 1088-9051 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR GA301/06/1334; GA ČR GA301/07/1383 Grant - others:Howard Hughes Medical Institute(US) HHMI 55000306 Institutional research plan: CEZ:AV0Z50520514 Keywords : chromosomal translocations * meiotic X chromosome inactivation * spermatogenesis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 11.224, year: 2007

  3. X-chromosome inactivation and escape

    Indian Academy of Sciences (India)

    2015-11-06

    Nov 6, 2015 ... tion and cancer in mice after a long period of time (Yildirim et al. 2013). ... chromosome of man has a short pairing seg- ment, that is not normally ..... Lyon M. F. 1988 The William Allan memorial award address: X-chromosome ...

  4. Genome Organization Drives Chromosome Fragility.

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    Canela, Andres; Maman, Yaakov; Jung, Seolkyoung; Wong, Nancy; Callen, Elsa; Day, Amanda; Kieffer-Kwon, Kyong-Rim; Pekowska, Aleksandra; Zhang, Hongliang; Rao, Suhas S P; Huang, Su-Chen; Mckinnon, Peter J; Aplan, Peter D; Pommier, Yves; Aiden, Erez Lieberman; Casellas, Rafael; Nussenzweig, André

    2017-07-27

    In this study, we show that evolutionarily conserved chromosome loop anchors bound by CCCTC-binding factor (CTCF) and cohesin are vulnerable to DNA double strand breaks (DSBs) mediated by topoisomerase 2B (TOP2B). Polymorphisms in the genome that redistribute CTCF/cohesin occupancy rewire DNA cleavage sites to novel loop anchors. While transcription- and replication-coupled genomic rearrangements have been well documented, we demonstrate that DSBs formed at loop anchors are largely transcription-, replication-, and cell-type-independent. DSBs are continuously formed throughout interphase, are enriched on both sides of strong topological domain borders, and frequently occur at breakpoint clusters commonly translocated in cancer. Thus, loop anchors serve as fragile sites that generate DSBs and chromosomal rearrangements. VIDEO ABSTRACT. Published by Elsevier Inc.

  5. X-chromosome inactivation in development and cancer.

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    Chaligné, Ronan; Heard, Edith

    2014-08-01

    X-chromosome inactivation represents an epigenetics paradigm and a powerful model system of facultative heterochromatin formation triggered by a non-coding RNA, Xist, during development. Once established, the inactive state of the Xi is highly stable in somatic cells, thanks to a combination of chromatin associated proteins, DNA methylation and nuclear organization. However, sporadic reactivation of X-linked genes has been reported during ageing and in transformed cells and disappearance of the Barr body is frequently observed in cancer cells. In this review we summarise current knowledge on the epigenetic changes that accompany X inactivation and discuss the extent to which the inactive X chromosome may be epigenetically or genetically perturbed in breast cancer. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  6. Conformation regulation of the X chromosome inactivation center: a model.

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    Antonio Scialdone

    2011-10-01

    Full Text Available X-Chromosome Inactivation (XCI is the process whereby one, randomly chosen X becomes transcriptionally silenced in female cells. XCI is governed by the Xic, a locus on the X encompassing an array of genes which interact with each other and with key molecular factors. The mechanism, though, establishing the fate of the X's, and the corresponding alternative modifications of the Xic architecture, is still mysterious. In this study, by use of computer simulations, we explore the scenario where chromatin conformations emerge from its interaction with diffusing molecular factors. Our aim is to understand the physical mechanisms whereby stable, non-random conformations are established on the Xic's, how complex architectural changes are reliably regulated, and how they lead to opposite structures on the two alleles. In particular, comparison against current experimental data indicates that a few key cis-regulatory regions orchestrate the organization of the Xic, and that two major molecular regulators are involved.

  7. MECP2 promoter methylation and X chromosome inactivation in autism.

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    Nagarajan, Raman P; Patzel, Katherine A; Martin, Michelle; Yasui, Dag H; Swanberg, Susan E; Hertz-Picciotto, Irva; Hansen, Robin L; Van de Water, Judy; Pessah, Isaac N; Jiang, Ruby; Robinson, Wendy P; LaSalle, Janine M

    2008-06-01

    Epigenetic mechanisms have been proposed to play a role in the etiology of autism. This hypothesis is supported by the discovery of increased MECP2 promoter methylation associated with decreased MeCP2 protein expression in autism male brain. To further understand the influence of female X chromosome inactivation (XCI) and neighboring methylation patterns on aberrant MECP2 promoter methylation in autism, multiple methylation analyses were peformed on brain and blood samples from individuals with autism. Bisulfite sequencing analyses of a region 0.6 kb upstream of MECP2 in brain DNA samples revealed an abrupt transition from a highly methylated region in both sexes to a region unmethylated in males and subject to XCI in females. Chromatin immunoprecipitation analysis demonstrated that the CCTC-binding factor (CTCF) bound to this transition region in neuronal cells, consistent with a chromatin boundary at the methylation transition. Male autism brain DNA samples displayed a slight increase in methylation in this transition region, suggesting a possible aberrant spreading of methylation into the MECP2 promoter in autism males across this boundary element. In addition, autistic female brain DNA samples showed evidence for aberrant MECP2 promoter methylation as an increase in the number of bisulfite sequenced clones with undefined XCI status for MECP2 but not androgen receptor (AR). To further investigate the specificity of MECP2 methylation alterations in autism, blood DNA samples from females and mothers of males with autism were also examined for XCI skewing at AR, but no significant increase in XCI skewing was observed compared to controls. These results suggest that the aberrant MECP2 methylation in autism brain DNA samples is due to locus-specific rather than global X chromosome methylation changes.

  8. Sex chromosome-specific regulation in the Drosophila male germline but little evidence for chromosomal dosage compensation or meiotic inactivation.

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    Colin D Meiklejohn

    2011-08-01

    Full Text Available The evolution of heteromorphic sex chromosomes (e.g., XY in males or ZW in females has repeatedly elicited the evolution of two kinds of chromosome-specific regulation: dosage compensation--the equalization of X chromosome gene expression in males and females--and meiotic sex chromosome inactivation (MSCI--the transcriptional silencing and heterochromatinization of the X during meiosis in the male (or Z in the female germline. How the X chromosome is regulated in the Drosophila melanogaster male germline is unclear. Here we report three new findings concerning gene expression from the X in Drosophila testes. First, X chromosome-wide dosage compensation appears to be absent from most of the Drosophila male germline. Second, microarray analysis provides no evidence for X chromosome-specific inactivation during meiosis. Third, we confirm the previous discovery that the expression of transgene reporters driven by autosomal spermatogenesis-specific promoters is strongly reduced when inserted on the X chromosome versus the autosomes; but we show that this chromosomal difference in expression is established in premeiotic cells and persists in meiotic cells. The magnitude of the X-autosome difference in transgene expression cannot be explained by the absence of dosage compensation, suggesting that a previously unrecognized mechanism limits expression from the X during spermatogenesis in Drosophila. These findings help to resolve several previously conflicting reports and have implications for patterns of genome evolution and speciation in Drosophila.

  9. Cytogenetic and molecular studies on a recombinant human X chromosome: implications for the spreading of X chromosome inactivation

    International Nuclear Information System (INIS)

    Mohandas, T.; Geller, R.L.; Yen, P.H.; Rosendorff, J.; Bernstein, R.; Yoshida, A.; Shapiro, L.J.

    1987-01-01

    A pericentric inversion of human X chromosome and a recombinant X chromosome [rec(X)] derived from crossing-over within the inversion was identified in a family. The rec(X) had a duplication of the segment Xq26.3 → Xqter and a deletion of Xp22.3 → Xpter and was interpreted to be Xqter → Xq26.3::Xp22.3 → Xqter. To characterize the rec(X) chromosome, dosage blots were done on genomic DNA from carriers of this rearranged X chromosome using a number of X chromosome probes. Results showed that anonymous sequences from the distal end of the long arm to which probes 4D8, Hx120A, DX13, and St14 bind as well as the locus for glucose-6-phosphate dehydrogenase (G6PD) wee duplicated on the rec(X). Mouse-human cell hybrids were constructed that retained the rec(X) in the active or inactive state. Analyses of these hybrid clones for markers from the distal short arm of the X chromosome showed that the rec(X) retained the loci for steroid sulfatase (STS) and the cell surface antigen 12E7 (MIC2); but not the pseudoautosomal sequence 113D. These molecular studies confirm that the rec(X) is a duplication-deficiency chromosome as expected. In the inactive state in cell hybrids, STS and MIC2 (which usually escape X chromosome inactivation) were expressed from the rec(X), whereas G6PD was not. Therefore, in the rec(X) X chromosome inactivation has spread through STS and MIC2 leaving these loci unaffected and has inactivated G6PD in the absence of an inactivation center in the q26.3 → qter region of the human X chromosome. The mechanism of spreading of inactivation appears to operate in a sequence-specific fashion. Alternatively, STS and MIC2 may have undergone inactivation initially but could not be maintained in an inactive state

  10. X-linked gene expression and X-chromosome inactivation: marsupials, mouse, and man compared.

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    VandeBerg, J L; Robinson, E S; Samollow, P B; Johnston, P G

    1987-01-01

    The existence of paternal X inactivation in Australian and American marsupial species suggests that this feature of X-chromosome dosage compensation is not a recent adaptation, but probably predates the evolutionary separation of the Australian and American marsupial lineages. Although it is theoretically possible that the marsupial system is one of random X inactivation with p greater than 0.99 and q less than 0.01 and dependent on parental source, no instance of random X inactivation (p = q or p not equal to q) has ever been verified in any tissue or cell type of any marsupial species. Therefore, we conclude that the most fundamental difference in X inactivation of marsupials and eutherians is whether the inactive X is the paternal one or is determined at random (with p = q in most but not all cases). The only other unequivocal difference between eutherians and marsupials is that both X chromosomes are active in mice and human oocytes, but not in kangaroo oocytes. Apparently, the inactive X is reactivated at a later meiotic stage or during early embryogenesis in kangaroos. X-chromosome inactivation takes place early in embryogenesis of eutherians and marsupials. Extraembryonic membranes of mice exhibit paternal X inactivation, whereas those of humans seem to exhibit random X inactivation with p greater than q (i.e., preferential paternal X inactivation). In general, extraembryonic membranes of marsupial exhibit paternal X inactivation, but the Gpd locus is active on both X chromosomes in at least some cells of kangaroo yolk sac. It is difficult to draw any general conclusion because of major differences in embryogeny of mice, humans, and marsupials, and uncertainties in interpreting the data from humans. Other differences between marsupials and eutherians in patterns of X-linked gene expression and X-chromosome inactivation seem to be quantitative rather than qualitative. Partial expression of some genes on the inactive X is characteristic of marsupials, with

  11. On the origin of sex chromosomes from meiotic drive

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    Úbeda, Francisco; Patten, Manus M.; Wild, Geoff

    2015-01-01

    Most animals and many plants make use of specialized chromosomes (sex chromosomes) to determine an individual's sex. Best known are the XY and ZW sex-determination systems. Despite having evolved numerous times, sex chromosomes present something of an evolutionary puzzle. At their origin, alleles that dictate development as one sex or the other (primitive sex chromosomes) face a selective penalty, as they will be found more often in the more abundant sex. How is it possible that primitive sex chromosomes overcome this disadvantage? Any theory for the origin of sex chromosomes must identify the benefit that outweighs this cost and enables a sex-determining mutation to establish in the population. Here we show that a new sex-determining allele succeeds when linked to a sex-specific meiotic driver. The new sex-determining allele benefits from confining the driving allele to the sex in which it gains the benefit of drive. Our model requires few special assumptions and is sufficiently general to apply to the evolution of sex chromosomes in outbreeding cosexual or dioecious species. We highlight predictions of the model that can discriminate between this and previous theories of sex-chromosome origins. PMID:25392470

  12. Caenorhabditis elegans histone methyltransferase MET-2 shields the male X chromosome from checkpoint machinery and mediates meiotic sex chromosome inactivation.

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    Paula M Checchi

    2011-09-01

    Full Text Available Meiosis is a specialized form of cellular division that results in the precise halving of the genome to produce gametes for sexual reproduction. Checkpoints function during meiosis to detect errors and subsequently to activate a signaling cascade that prevents the formation of aneuploid gametes. Indeed, asynapsis of a homologous chromosome pair elicits a checkpoint response that can in turn trigger germline apoptosis. In a heterogametic germ line, however, sex chromosomes proceed through meiosis with unsynapsed regions and are not recognized by checkpoint machinery. We conducted a directed RNAi screen in Caenorhabditis elegans to identify regulatory factors that prevent recognition of heteromorphic sex chromosomes as unpaired and uncovered a role for the SET domain histone H3 lysine 9 histone methyltransferase (HMTase MET-2 and two additional HMTases in shielding the male X from checkpoint machinery. We found that MET-2 also mediates the transcriptional silencing program of meiotic sex chromosome inactivation (MSCI but not meiotic silencing of unsynapsed chromatin (MSUC, suggesting that these processes are distinct. Further, MSCI and checkpoint shielding can be uncoupled, as double-strand breaks targeted to an unpaired, transcriptionally silenced extra-chromosomal array induce checkpoint activation in germ lines depleted for met-2. In summary, our data uncover a mechanism by which repressive chromatin architecture enables checkpoint proteins to distinguish between the partnerless male X chromosome and asynapsed chromosomes thereby shielding the lone X from inappropriate activation of an apoptotic program.

  13. Imprinted X chromosome inactivation: evolution of mechanisms in distantly related mammals

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    Shafagh A. Waters

    2015-03-01

    Full Text Available In females, X chromosome inactivation (XCI ensures transcriptional silencing of one of the two Xs (either in a random or imprinted fashion in somatic cells. Comparing this silencing between species has offered insight into different mechanisms of X inactivation, providing clues into the evolution of this epigenetic process in mammals. Long-noncoding RNAs have emerged as a common theme in XCI of therian mammals (eutherian and marsupial. Eutherian X inactivation is regulated by the noncoding RNA product of XIST, within a cis-acting master control region called the X inactivation center (XIC. Marsupials XCI is XIST independent. Instead, XCI is controlled by the long-noncoding RNA Rsx, which appears to be a functional analog of the eutherian XIST gene, insofar that its transcript coats the inactive X and represses activity of genes in cis. In this review we discuss XCI in eutherians, and contrast imprinted X inactivation in mouse and marsupials. We provide particular focus on the evolution of genomic elements that confer the unique epigenetic features that characterize the inactive X chromosome.

  14. Risk scaling factors from inactivation to chromosome aberrations, mutations and oncogenic transformations in mammalian cells

    International Nuclear Information System (INIS)

    Alkaharam, A.S.; Watt, D.E.

    1997-01-01

    Analyses of bio-effect mechanisms of damage to mammalian cells in terms of the quality parameter 'mean free path for primary ionisation', for heavy charged particles, strongly suggests that there is a common mechanism for the biological endpoints of chromosome aberrations, mutations and oncogenic transformation. The lethal lesions are identified as unrepaired double-strand breaks in the intracellular DNA. As data for the various endpoints studied can be represented in a unified scheme, for any radiation type, it follows that radiation risk factors can be determined on the basis of simple ratios to the inactivation cross sections. There are intrinsic physical reasons why neutrons can never reach the saturation level of heavier particles for equal fluences. The probabilities of risk with respect to inactivation, for chromosome dicentrics, mutation of the HPRT gene and of oncogenic transformation are respectively 0.24, 5.8 x 10 -5 , and 4.1 x 10 -3 . (author)

  15. Chromosomal gene inactivation in the green sulfur bacterium Chlorobium tepidum by natural transformation

    DEFF Research Database (Denmark)

    Frigaard, N-U; Bryant, D A

    2001-01-01

    Conditions for inactivating chromosomal genes of Chlorobium tepidum by natural transformation and homologous recombination were established. As a model, mutants unable to perform nitrogen fixation were constructed by interrupting nifD with various antibiotic resistance markers. Growth of wild...

  16. Sexually antagonistic "zygotic drive" of the sex chromosomes.

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    William R Rice

    2008-12-01

    Full Text Available Genomic conflict is perplexing because it causes the fitness of a species to decline rather than improve. Many diverse forms of genomic conflict have been identified, but this extant tally may be incomplete. Here, we show that the unusual characteristics of the sex chromosomes can, in principle, lead to a previously unappreciated form of sexual genomic conflict. The phenomenon occurs because there is selection in the heterogametic sex for sex-linked mutations that harm the sex of offspring that does not carry them, whenever there is competition among siblings. This harmful phenotype can be expressed as an antagonistic green-beard effect that is mediated by epigenetic parental effects, parental investment, and/or interactions among siblings. We call this form of genomic conflict sexually antagonistic "zygotic drive", because it is functionally equivalent to meiotic drive, except that it operates during the zygotic and postzygotic stages of the life cycle rather than the meiotic and gametic stages. A combination of mathematical modeling and a survey of empirical studies is used to show that sexually antagonistic zygotic drive is feasible, likely to be widespread in nature, and that it can promote a genetic "arms race" between the homo- and heteromorphic sex chromosomes. This new category of genomic conflict has the potential to strongly influence other fundamental evolutionary processes, such as speciation and the degeneration of the Y and W sex chromosomes. It also fosters a new genetic hypothesis for the evolution of enigmatic fitness-reducing traits like the high frequency of spontaneous abortion, sterility, and homosexuality observed in humans.

  17. Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

    Science.gov (United States)

    Machiela, Mitchell J.; Zhou, Weiyin; Karlins, Eric; Sampson, Joshua N.; Freedman, Neal D.; Yang, Qi; Hicks, Belynda; Dagnall, Casey; Hautman, Christopher; Jacobs, Kevin B.; Abnet, Christian C.; Aldrich, Melinda C.; Amos, Christopher; Amundadottir, Laufey T.; Arslan, Alan A.; Beane-Freeman, Laura E.; Berndt, Sonja I.; Black, Amanda; Blot, William J.; Bock, Cathryn H.; Bracci, Paige M.; Brinton, Louise A.; Bueno-de-Mesquita, H Bas; Burdett, Laurie; Buring, Julie E.; Butler, Mary A.; Canzian, Federico; Carreón, Tania; Chaffee, Kari G.; Chang, I-Shou; Chatterjee, Nilanjan; Chen, Chu; Chen, Constance; Chen, Kexin; Chung, Charles C.; Cook, Linda S.; Crous Bou, Marta; Cullen, Michael; Davis, Faith G.; De Vivo, Immaculata; Ding, Ti; Doherty, Jennifer; Duell, Eric J.; Epstein, Caroline G.; Fan, Jin-Hu; Figueroa, Jonine D.; Fraumeni, Joseph F.; Friedenreich, Christine M.; Fuchs, Charles S.; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M.; Garcia-Closas, Montserrat; Gaudet, Mia M.; Gaziano, J. Michael; Giles, Graham G.; Gillanders, Elizabeth M.; Giovannucci, Edward L.; Goldin, Lynn; Goldstein, Alisa M.; Haiman, Christopher A.; Hallmans, Goran; Hankinson, Susan E.; Harris, Curtis C.; Henriksson, Roger; Holly, Elizabeth A.; Hong, Yun-Chul; Hoover, Robert N.; Hsiung, Chao A.; Hu, Nan; Hu, Wei; Hunter, David J.; Hutchinson, Amy; Jenab, Mazda; Johansen, Christoffer; Khaw, Kay-Tee; Kim, Hee Nam; Kim, Yeul Hong; Kim, Young Tae; Klein, Alison P.; Klein, Robert; Koh, Woon-Puay; Kolonel, Laurence N.; Kooperberg, Charles; Kraft, Peter; Krogh, Vittorio; Kurtz, Robert C.; LaCroix, Andrea; Lan, Qing; Landi, Maria Teresa; Marchand, Loic Le; Li, Donghui; Liang, Xiaolin; Liao, Linda M.; Lin, Dongxin; Liu, Jianjun; Lissowska, Jolanta; Lu, Lingeng; Magliocco, Anthony M.; Malats, Nuria; Matsuo, Keitaro; McNeill, Lorna H.; McWilliams, Robert R.; Melin, Beatrice S.; Mirabello, Lisa; Moore, Lee; Olson, Sara H.; Orlow, Irene; Park, Jae Yong; Patiño-Garcia, Ana; Peplonska, Beata; Peters, Ulrike; Petersen, Gloria M.; Pooler, Loreall; Prescott, Jennifer; Prokunina-Olsson, Ludmila; Purdue, Mark P.; Qiao, You-Lin; Rajaraman, Preetha; Real, Francisco X.; Riboli, Elio; Risch, Harvey A.; Rodriguez-Santiago, Benjamin; Ruder, Avima M.; Savage, Sharon A.; Schumacher, Fredrick; Schwartz, Ann G.; Schwartz, Kendra L.; Seow, Adeline; Wendy Setiawan, Veronica; Severi, Gianluca; Shen, Hongbing; Sheng, Xin; Shin, Min-Ho; Shu, Xiao-Ou; Silverman, Debra T.; Spitz, Margaret R.; Stevens, Victoria L.; Stolzenberg-Solomon, Rachael; Stram, Daniel; Tang, Ze-Zhong; Taylor, Philip R.; Teras, Lauren R.; Tobias, Geoffrey S.; Van Den Berg, David; Visvanathan, Kala; Wacholder, Sholom; Wang, Jiu-Cun; Wang, Zhaoming; Wentzensen, Nicolas; Wheeler, William; White, Emily; Wiencke, John K.; Wolpin, Brian M.; Wong, Maria Pik; Wu, Chen; Wu, Tangchun; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S.; Xia, Lucy; Yang, Hannah P.; Yang, Pan-Chyr; Yu, Kai; Zanetti, Krista A.; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Zhou, Baosen; Ziegler, Regina G.; Perez-Jurado, Luis A.; Caporaso, Neil E.; Rothman, Nathaniel; Tucker, Margaret; Dean, Michael C.; Yeager, Meredith; Chanock, Stephen J.

    2016-01-01

    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases. PMID:27291797

  18. Meiotic recombination, synapsis, meiotic inactivation and sperm aneuploidy in a chromosome 1 inversion carrier.

    Science.gov (United States)

    Kirkpatrick, Gordon; Chow, Victor; Ma, Sai

    2012-01-01

    Disrupted meiotic behaviour of inversion carriers may be responsible for suboptimal sperm parameters in these carriers. This study investigated meiotic recombination, synapsis, transcriptional silencing and chromosome segregation effects in a pericentric inv(1) carrier. Recombination (MLH1), synapsis (SYCP1, SYCP3) and transcriptional inactivation (γH2AX, BRCA1) were examined by fluorescence immunostaining. Chromosome specific rates of recombination were determined by fluorescence in-situ hybridization. Furthermore, testicular sperm was examined for aneuploidy and segregation of the inv(1). Our findings showed that global recombination rates were similar to controls. Recombination on the inv(1) and the sex chromosomes were reduced. The inv(1) associated with the XY body in 43.4% of cells, in which XY recombination was disproportionately absent, and 94.3% of cells displayed asynapsed regions which displayed meiotic silencing regardless of their association with the XY body. Furthermore, a low frequency of chromosomal imbalance was observed in spermatozoa (3.4%). Our results suggest that certain inversion carriers may display unimpaired global recombination and impaired recombination on the involved and the sex chromosomes during meiosis. Asynapsis or inversion-loop formation in the inverted region may be responsible for impaired spermatogenesis and may prevent sperm-chromosome imbalance. Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  19. Abnormal X : autosome ratio, but normal X chromosome inactivation in human triploid cultures

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    Norwood Thomas H

    2006-07-01

    Full Text Available Abstract Background X chromosome inactivation (XCI is that aspect of mammalian dosage compensation that brings about equivalence of X-linked gene expression between females and males by inactivating one of the two X chromosomes (Xi in normal female cells, leaving them with a single active X (Xa as in male cells. In cells with more than two X's, but a diploid autosomal complement, all X's but one, Xa, are inactivated. This phenomenon is commonly thought to suggest 1 that normal development requires a ratio of one Xa per diploid autosomal set, and 2 that an early event in XCI is the marking of one X to be active, with remaining X's becoming inactivated by default. Results Triploids provide a test of these ideas because the ratio of one Xa per diploid autosomal set cannot be achieved, yet this abnormal ratio should not necessarily affect the one-Xa choice mechanism for XCI. Previous studies of XCI patterns in murine triploids support the single-Xa model, but human triploids mostly have two-Xa cells, whether they are XXX or XXY. The XCI patterns we observe in fibroblast cultures from different XXX human triploids suggest that the two-Xa pattern of XCI is selected for, and may have resulted from rare segregation errors or Xi reactivation. Conclusion The initial X inactivation pattern in human triploids, therefore, is likely to resemble the pattern that predominates in murine triploids, i.e., a single Xa, with the remaining X's inactive. Furthermore, our studies of XIST RNA accumulation and promoter methylation suggest that the basic features of XCI are normal in triploids despite the abnormal X:autosome ratio.

  20. Prognostic value of X-chromosome inactivation in symptomatic female carriers of dystrophinopathy

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    Juan-Mateu Jonàs

    2012-10-01

    Full Text Available Abstract Background Between 8% and 22% of female carriers of DMD mutations exhibit clinical symptoms of variable severity. Development of symptoms in DMD mutation carriers without chromosomal rearrangements has been attributed to skewed X-chromosome inactivation (XCI favouring predominant expression of the DMD mutant allele. However the prognostic use of XCI analysis is controversial. We aimed to evaluate the correlation between X-chromosome inactivation and development of clinical symptoms in a series of symptomatic female carriers of dystrophinopathy. Methods We reviewed the clinical, pathological and genetic features of twenty-four symptomatic carriers covering a wide spectrum of clinical phenotypes. DMD gene analysis was performed using MLPA and whole gene sequencing in blood DNA and muscle cDNA. Blood and muscle DNA was used for X-chromosome inactivation (XCI analysis thought the AR methylation assay in symptomatic carriers and their female relatives, asymptomatic carriers as well as non-carrier females. Results Symptomatic carriers exhibited 49.2% more skewed XCI profiles than asymptomatic carriers. The extent of XCI skewing in blood tended to increase in line with the severity of muscle symptoms. Skewed XCI patterns were found in at least one first-degree female relative in 78.6% of symptomatic carrier families. No mutations altering XCI in the XIST gene promoter were found. Conclusions Skewed XCI is in many cases familial inherited. The extent of XCI skewing is related to phenotype severity. However, the assessment of XCI by means of the AR methylation assay has a poor prognostic value, probably because the methylation status of the AR gene in muscle may not reflect in all cases the methylation status of the DMD gene.

  1. Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

    DEFF Research Database (Denmark)

    Machiela, Mitchell J; Zhou, Weiyin; Karlins, Eric

    2016-01-01

    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chrom...

  2. A History of the Discovery of Random X Chromosome Inactivation in the Human Female and its Significance

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    Sophia Balderman

    2011-07-01

    Full Text Available Genetic determinants of sex in placental mammals developed by the evolution of primordial autosomes into the male and female sex chromosomes. The Y chromosome determines maleness by the action of the gene SRY, which encodes a protein that initiates a sequence of events prompting the embryonic gonads to develop into testes. The X chromosome in the absence of a Y chromosome results in a female by permitting the conversion of the embryonic gonads into ovaries. We trace the historical progress that resulted in the discovery that one X chromosome in the female is randomly inactivated in early embryogenesis, accomplishing approximate equivalency of X chromosome gene dosage in both sexes. This event results in half of the somatic cells in a tissue containing proteins encoded by the genes of the maternal X chromosome and half having proteins encoded by the genes of the paternal X chromosome, on average, accounting for the phenotype of a female heterozygote with an X chromosome mutation. The hypothesis of X chromosome inactivation as a random event early in embryogenesis was first described as a result of studies of variegated coat color in female mice. Similar results were found in women using the X chromosome-linked gene, glucose-6-phosphate dehydrogenase, studied in red cells. The random inactivation of the X chromosome-bearing genes for isoenzyme types A and B of glucose-6-phosphate dehydrogenase was used to establish the clonal origin of neoplasms in informative women with leiomyomas. Behind these discoveries are the stories of the men and women scientists whose research enlightened these aspects of X chromosome function and their implication for medicine.

  3. The Phosphatase Dusp7 Drives Meiotic Resumption and Chromosome Alignment in Mouse Oocytes

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    Thomas Tischer

    2016-10-01

    Full Text Available Mammalian oocytes are stored in the ovary, where they are arrested in prophase for prolonged periods. The mechanisms that abrogate the prophase arrest in mammalian oocytes and reinitiate meiosis are not well understood. Here, we identify and characterize an essential pathway for the resumption of meiosis that relies on the protein phosphatase DUSP7. DUSP7-depleted oocytes either fail to resume meiosis or resume meiosis with a significant delay. In the absence of DUSP7, Cdk1/CycB activity drops below the critical level required to reinitiate meiosis, precluding or delaying nuclear envelope breakdown. Our data suggest that DUSP7 drives meiotic resumption by dephosphorylating and thereby inactivating cPKC isoforms. In addition to controlling meiotic resumption, DUSP7 has a second function in chromosome segregation: DUSP7-depleted oocytes that enter meiosis show severe chromosome alignment defects and progress into anaphase prematurely. Altogether, these findings establish the phosphatase DUSP7 as an essential regulator of multiple steps in oocyte meiosis.

  4. Human X chromosome inactivation and reactivation: implications for cell reprogramming and disease.

    Science.gov (United States)

    Cantone, Irene; Fisher, Amanda G

    2017-11-05

    X-chromosome inactivation (XCI) is an exemplar of epigenetic regulation that is set up as pluripotent cells differentiate. Once established, XCI is stably propagated, but can be reversed in vivo or by pluripotent reprogramming in vitro Although reprogramming provides a useful model for inactive X (Xi) reactivation in mouse, the relative instability and heterogeneity of human embryonic stem (ES) cells and induced pluripotent stem cells hampers comparable progress in human. Here we review studies aimed at reactivating the human Xi using different reprogramming strategies. We outline our recent results using mouse ES cells to reprogramme female human fibroblasts by cell-cell fusion. We show that pluripotent reprogramming induces widespread and rapid chromatin remodelling in which the human Xi loses XIST and H3K27m3 enrichment and selected Xi genes become reactivated, ahead of mitotic division. Using RNA sequencing to map the extent of human Xi reactivation, and chromatin-modifying drugs to potentiate reactivation, we outline how this approach could be used to better design strategies to re-express human X-linked loci. As cell fusion induces the expression of human pluripotency genes that represent both the 'primed' and 'naive' states, this approach may also offer a fresh opportunity to segregate human pluripotent states with distinct Xi expression profiles, using single-cell-based approaches.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'. © 2017 The Author(s).

  5. Detection of Turner syndrome using X-chromosome inactivation specific differentially methylated CpG sites: A pilot study.

    Science.gov (United States)

    Zhang, Qiang; Guo, Xiaohong; Tian, Tian; Wang, Teng; Li, Qiaoli; Wang, Lei; Liu, Yun; Xing, Qinghe; He, Lin; Zhao, Xinzhi

    2017-05-01

    Early diagnosis of Turner syndrome (TS) may improve preventive measures and treatment. X-chromosome inactivation specific differentially methylated CpG sites (XIDMSs) that are high methylated in inactive X chromosomes (Xi) and unmethylated in active X chromosomes (Xa) may be potential makers for TS detection. The candidate XIDMSs were screened from 9 male and 12 female DNA samples with normal karyotypes using the Illumina 450k array and validated by bisulfite sequencing PCR and pyrosequencing assay. X chromosome dosage was calculated according to the methylation level of multiple XIDMSs. Overall, 108 candidate XIDMSs were screened by the 450k array. Validations indicated that XIDMSs gathered and formed the X-chromosome inactivation specific differentially methylated regions (XIDMRs). Using 3 XIDMRs at SAT1, UXT and UTP14A loci, 36 TS, 22 normal female and 6 male samples were analyzed. Methylation levels of the 20 XIDMSs in the XIDMRs could distinguish between TS and normal female DNA samples, the X chromosome dosage was consistent with karyotyping data. Analyzing samples of 2 triple X syndrome and 3 Klinefelter syndrome patients suggested that this method could be used to detect X chromosome aneuploids other than TS. XIDMSs are widely spread along the X chromosome and might be effective markers for detection of TS and other X chromosome aneuploids. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Meiotic sex chromosome inactivation is disrupted in sterile hybrid male house mice.

    Science.gov (United States)

    Campbell, Polly; Good, Jeffrey M; Nachman, Michael W

    2013-03-01

    In male mammals, the X and Y chromosomes are transcriptionally silenced in primary spermatocytes by meiotic sex chromosome inactivation (MSCI) and remain repressed for the duration of spermatogenesis. Here, we test the longstanding hypothesis that disrupted MSCI might contribute to the preferential sterility of heterogametic hybrid males. We studied a cross between wild-derived inbred strains of Mus musculus musculus and M. m. domesticus in which sterility is asymmetric: F1 males with a M. m. musculus mother are sterile or nearly so while F1 males with a M. m. domesticus mother are normal. In previous work, we discovered widespread overexpression of X-linked genes in the testes of sterile but not fertile F1 males. Here, we ask whether this overexpression is specifically a result of disrupted MSCI. To do this, we isolated cells from different stages of spermatogenesis and measured the expression of several genes using quantitative PCR. We found that X overexpression in sterile F1 primary spermatocytes is coincident with the onset of MSCI and persists in postmeiotic spermatids. Using a series of recombinant X genotypes, we then asked whether X overexpression in hybrids is controlled by cis-acting loci across the X chromosome. We found that it is not. Instead, one large interval in the proximal portion of the M. m. musculus X chromosome is associated with both overexpression and the severity of sterility phenotypes in hybrids. These results demonstrate a strong association between X-linked hybrid male sterility and disruption of MSCI and suggest that trans-acting loci on the X are important for the transcriptional regulation of the X chromosome during spermatogenesis.

  7. Chromosomal instability drives metastasis through a cytosolic DNA response.

    Science.gov (United States)

    Bakhoum, Samuel F; Ngo, Bryan; Laughney, Ashley M; Cavallo, Julie-Ann; Murphy, Charles J; Ly, Peter; Shah, Pragya; Sriram, Roshan K; Watkins, Thomas B K; Taunk, Neil K; Duran, Mercedes; Pauli, Chantal; Shaw, Christine; Chadalavada, Kalyani; Rajasekhar, Vinagolu K; Genovese, Giulio; Venkatesan, Subramanian; Birkbak, Nicolai J; McGranahan, Nicholas; Lundquist, Mark; LaPlant, Quincey; Healey, John H; Elemento, Olivier; Chung, Christine H; Lee, Nancy Y; Imielenski, Marcin; Nanjangud, Gouri; Pe'er, Dana; Cleveland, Don W; Powell, Simon N; Lammerding, Jan; Swanton, Charles; Cantley, Lewis C

    2018-01-25

    Chromosomal instability is a hallmark of cancer that results from ongoing errors in chromosome segregation during mitosis. Although chromosomal instability is a major driver of tumour evolution, its role in metastasis has not been established. Here we show that chromosomal instability promotes metastasis by sustaining a tumour cell-autonomous response to cytosolic DNA. Errors in chromosome segregation create a preponderance of micronuclei whose rupture spills genomic DNA into the cytosol. This leads to the activation of the cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) cytosolic DNA-sensing pathway and downstream noncanonical NF-κB signalling. Genetic suppression of chromosomal instability markedly delays metastasis even in highly aneuploid tumour models, whereas continuous chromosome segregation errors promote cellular invasion and metastasis in a STING-dependent manner. By subverting lethal epithelial responses to cytosolic DNA, chromosomally unstable tumour cells co-opt chronic activation of innate immune pathways to spread to distant organs.

  8. The probability to initiate X chromosome inactivation is determined by the X to autosomal ratio and X chromosome specific allelic properties.

    Directory of Open Access Journals (Sweden)

    Kim Monkhorst

    Full Text Available In female mammalian cells, random X chromosome inactivation (XCI equalizes the dosage of X-encoded gene products to that in male cells. XCI is a stochastic process, in which each X chromosome has a probability to be inactivated. To obtain more insight in the factors setting up this probability, we studied the role of the X to autosome (X ratio A ratio in initiation of XCI, and have used the experimental data in a computer simulation model to study the cellular population dynamics of XCI.To obtain more insight in the role of the XratioA ratio in initiation of XCI, we generated triploid mouse ES cells by fusion of haploid round spermatids with diploid female and male ES cells. These fusion experiments resulted in only XXY triploid ES cells. XYY and XXX ES lines were absent, suggesting cell death related either to insufficient X-chromosomal gene dosage (XYY or to inheritance of an epigenetically modified X chromosome (XXX. Analysis of active (Xa and inactive (Xi X chromosomes in the obtained triploid XXY lines indicated that the initiation frequency of XCI is low, resulting in a mixed population of XaXiY and XaXaY cells, in which the XaXiY cells have a small proliferative advantage. This result, and findings on XCI in diploid and tetraploid ES cell lines with different X ratio A ratios, provides evidence that the X ratio A ratio determines the probability for a given X chromosome to be inactivated. Furthermore, we found that the kinetics of the XCI process can be simulated using a probability for an X chromosome to be inactivated that is proportional to the X ratio A ratio. These simulation studies re-emphasize our hypothesis that the probability is a function of the concentration of an X-encoded activator of XCI, and of X chromosome specific allelic properties determining the threshold for this activator.The present findings reveal that the probability for an X chromosome to be inactivated is proportional to the X ratio A ratio. This finding

  9. Empirical evidence for son-killing X chromosomes and the operation of SA-zygotic drive.

    Directory of Open Access Journals (Sweden)

    Urban Friberg

    Full Text Available Diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. This causes a fundamental genetic conflict over transmission rate between alternative alleles. Single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype. However, all genes on a male's X and Y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive phenotype. Correspondingly, the well-characterized phenomenon of male gametic drive, occurring during haploid gametogenesis, is especially common on sex chromosomes. The new theory of sexually antagonistic zygotic drive of the sex chromosomes (SA-zygotic drive extends the logic of gametic drive into the diploid phase of the lifecycle, whenever there is competition among siblings or harmful sib-sib mating. The X and Y are predicted to gain a transmission advantage by harming offspring of the sex that does not carry them.Here we analyzed a mutant X-chromosome in Drosophila simulans that produced an excess of daughters when transmitted from males. We developed a series of tests to differentiate between gametic and SA-zygotic drive, and provide multiple lines of evidence that SA-zygotic drive is responsible for the sex ratio bias. Driving sires produce about 50% more surviving daughters than sons.Sex-ratio distortion due to genetic conflict has evolved via gametic drive and maternally transmitted endosymbionts. Our data indicate that sex chromosomes can also drive by harming the non-carrier sex of offspring.

  10. Empirical evidence for son-killing X chromosomes and the operation of SA-zygotic drive.

    Science.gov (United States)

    Friberg, Urban; Stewart, Andrew D; Rice, William R

    2011-01-01

    Diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. This causes a fundamental genetic conflict over transmission rate between alternative alleles. Single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype). However, all genes on a male's X and Y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive phenotype. Correspondingly, the well-characterized phenomenon of male gametic drive, occurring during haploid gametogenesis, is especially common on sex chromosomes. The new theory of sexually antagonistic zygotic drive of the sex chromosomes (SA-zygotic drive) extends the logic of gametic drive into the diploid phase of the lifecycle, whenever there is competition among siblings or harmful sib-sib mating. The X and Y are predicted to gain a transmission advantage by harming offspring of the sex that does not carry them. Here we analyzed a mutant X-chromosome in Drosophila simulans that produced an excess of daughters when transmitted from males. We developed a series of tests to differentiate between gametic and SA-zygotic drive, and provide multiple lines of evidence that SA-zygotic drive is responsible for the sex ratio bias. Driving sires produce about 50% more surviving daughters than sons. Sex-ratio distortion due to genetic conflict has evolved via gametic drive and maternally transmitted endosymbionts. Our data indicate that sex chromosomes can also drive by harming the non-carrier sex of offspring.

  11. Clustering of double strand break-containing chromosome domains is not inhibited by inactivation of major repair proteins

    International Nuclear Information System (INIS)

    Krawczyk, P. M.; Stap, C.; Van Oven, C.; Hoebe, R.; Aten, J. A.

    2006-01-01

    For efficient repair of DNA double strand breaks (DSBs) cells rely on a process that involves the Mre11/Rad50/Nbs1 complex, which may help to protect non-repaired DNA ends from separating until they can be rejoined by DNA repair proteins. It has been observed that as a secondary effect, this process can lead to unintended clustering of multiple, initially separate, DSB-containing chromosome domains. This work demonstrates that neither inactivation of the major repair proteins XRCC3 and the DNA-dependent protein kinase (DNA-PK) nor inhibition of DNA-PK by vanillin influences the aggregation of DSB-containing chromosome domains. (authors)

  12. Independent clonal origin of multiple uterine leiomyomas that was determined by X chromosome inactivation and microsatellite analysis

    DEFF Research Database (Denmark)

    Canevari, Renata A; Pontes, Anaglória; Rosa, Fabíola E

    2005-01-01

    OBJECTIVE: In an attempt to clarify the clonality and genetic relationships that are involved in the tumorigenesis of uterine leiomyomas, we used a total of 43 multiple leiomyomas from 14 patients and analyzed the allelic status with 15 microsatellite markers and X chromosome inactivation analysis...... of the 9 of 12 informative patients; different inactivation patterns were observed in 3 cases. CONCLUSION: Our data support the concept that uterine leiomyomas are derived from a single cell but are generated independently in the uterus. Loss of heterozygosity findings at 7p22-15 are consistent...... with previous data that suggested the relevance of chromosomal aberrations at 7p that were involved in individual uterine leiomyomas....

  13. Impaired imprinted X chromosome inactivation is responsible for the skewed sex ratio following in vitro fertilization

    Science.gov (United States)

    Tan, Kun; An, Lei; Miao, Kai; Ren, Likun; Hou, Zhuocheng; Tao, Li; Zhang, Zhenni; Wang, Xiaodong; Xia, Wei; Liu, Jinghao; Wang, Zhuqing; Xi, Guangyin; Gao, Shuai; Sui, Linlin; Zhu, De-Sheng; Wang, Shumin; Wu, Zhonghong; Bach, Ingolf; Chen, Dong-bao; Tian, Jianhui

    2016-01-01

    Dynamic epigenetic reprogramming occurs during normal embryonic development at the preimplantation stage. Erroneous epigenetic modifications due to environmental perturbations such as manipulation and culture of embryos during in vitro fertilization (IVF) are linked to various short- or long-term consequences. Among these, the skewed sex ratio, an indicator of reproductive hazards, was reported in bovine and porcine embryos and even human IVF newborns. However, since the first case of sex skewing reported in 1991, the underlying mechanisms remain unclear. We reported herein that sex ratio is skewed in mouse IVF offspring, and this was a result of female-biased peri-implantation developmental defects that were originated from impaired imprinted X chromosome inactivation (iXCI) through reduced ring finger protein 12 (Rnf12)/X-inactive specific transcript (Xist) expression. Compensation of impaired iXCI by overexpression of Rnf12 to up-regulate Xist significantly rescued female-biased developmental defects and corrected sex ratio in IVF offspring. Moreover, supplementation of an epigenetic modulator retinoic acid in embryo culture medium up-regulated Rnf12/Xist expression, improved iXCI, and successfully redeemed the skewed sex ratio to nearly 50% in mouse IVF offspring. Thus, our data show that iXCI is one of the major epigenetic barriers for the developmental competence of female embryos during preimplantation stage, and targeting erroneous epigenetic modifications may provide a potential approach for preventing IVF-associated complications. PMID:26951653

  14. B chromosomes and Robertsonian fusions of Dichroplus pratensis (Acrididae): intraspecific support for the centromeric drive theory.

    Science.gov (United States)

    Bidau, C J; Martí, D A

    2004-01-01

    We tested the centromeric drive theory of karyotypic evolution in the grasshopper Dichroplus pratensis, which is simultaneously polymorphic for eight Robertsonian fusions and two classes of B chromosomes. A logistic regression analysis performed on 53 natural populations from Argentina revealed that B chromosomes are more probably found in populations with a higher proportion of acrocentric chromosomes, as the theory predicts. Furthermore, frequencies of B-carrying individuals are significantly negatively correlated with the mean frequency of different Robertsonian fusions per individual. No significant correlations between presence/absence or frequency of Bs, and latitude or altitude of the sampled populations, were found. We thus provide the first intraspecific evidence supporting the centromeric drive theory in relation to the establishment of B chromosomes in natural populations. Copyright 2004 S. Karger AG, Basel

  15. Meiotic drive on aberrant chromosome 1 in the mouse is determined by a linked distorter.

    Science.gov (United States)

    Agulnik, S I; Sabantsev, I D; Orlova, G V; Ruvinsky, A O

    1993-04-01

    An aberrant chromosome 1 carrying an inverted fragment with two amplified DNA regions was isolated from wild populations of Mus musculus. Meiotic drive favouring the aberrant chromosome was demonstrated for heterozygous females. Its cause was preferential passage of aberrant chromosome 1 to the oocyte. Genetic analysis allowed us to identify a two-component system conditioning deviation from equal segregation of the homologues. The system consists of a postulated distorter and responder. The distorter is located on chromosome 1 distally to the responder, between the ln and Pep-3 genes, and it acts on the responder when in trans position. Polymorphism of the distorters was manifested as variation in their effect on meiotic drive level in the laboratory strain and mice from wild populations.

  16. Reduced polymorphism associated with X chromosome meiotic drive in the stalk-eyed fly Teleopsis dalmanni.

    Directory of Open Access Journals (Sweden)

    Sarah J Christianson

    Full Text Available Sex chromosome meiotic drive has been suggested as a cause of several evolutionary genetic phenomena, including genomic conflicts that give rise to reproductive isolation between new species. In this paper we present a population genetic analysis of X chromosome drive in the stalk-eyed fly, Teleopsis dalmanni, to determine how this natural polymorphism influences genetic diversity. We analyzed patterns of DNA sequence variation at two X-linked regions (comprising 1325 bp approximately 50 cM apart and one autosomal region (comprising 921 bp for 50 males, half of which were collected in the field from one of two allopatric locations and the other half were derived from lab-reared individuals with known brood sex ratios. These two populations are recently diverged but exhibit partial postzygotic reproductive isolation, i.e. crosses produce sterile hybrid males and fertile females. We find no nucleotide or microsatellite variation on the drive X chromosome, whereas the same individuals show levels of variation at autosomal regions that are similar to field-collected flies. Furthermore, one field-caught individual collected 10 years previously had a nearly identical X haplotype to the drive X, and is over 2% divergent from other haplotypes sampled from the field. These results are consistent with a selective sweep that has removed genetic variation from much of the drive X chromosome. We discuss how this finding may relate to the rapid evolution of postzygotic reproductive isolation that has been documented for these flies.

  17. Nondisjunction in Favor of a Chromosome: The Mechanism of Rye B Chromosome Drive during Pollen Mitosis

    Czech Academy of Sciences Publication Activity Database

    Banaei-Moghaddam, A.M.; Schubert, V.; Kumke, K.; Weiβ, O.; Klemme, S.; Nagaki, K.; Macas, Jiří; González-Sánchez, M.; Heredia, V.; Gómez-Revilla, D.; González-García, M.; Vega, J.M.; Puertas, M.J.; Houben, A.

    2012-01-01

    Roč. 24, č. 10 (2012), s. 4124-4134 ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50510513 Keywords : chromosomes * centromere * repeats Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.251, year: 2012

  18. Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H. [Ulleval Univ. Hospital, Oslo (Norway)] [and others

    1995-03-27

    Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.

  19. What Drives Embryo Development? Chromosomal Normality or Mitochondria?

    Directory of Open Access Journals (Sweden)

    A. Bayram

    2017-01-01

    Full Text Available Objective. To report the arrest of euploid embryos with high mtDNA content. Design. A report of 2 cases. Setting. Private fertility clinic. Patients. 2 patients, 45 and 40 years old undergoing IVF treatment. Interventions. Mature oocytes were collected and vitrified from two ovarian stimulations. Postthaw, survived mature oocytes underwent fertilization by intracytoplasmic sperm injection (ICSI. Preimplantation genetic screening (PGS and mitochondrial DNA (mtDNA copy number were done using next generation sequencing (NGS. The only normal embryo among the all-biopsied embryos had the highest “Mitoscore” value and was the only arrested embryo in both cases. Therefore, the embryo transfer was cancelled. Main Outcome Measures. Postthaw survival and fertilization rate, embryo euploidy, mtDNA copy number, and embryo development. Results. In both patients, after PGS only 1 embryo was euploid. Both embryos had the highest mtDNA copy number from all tested embryos and both embryos were arrested on further development. Conclusions. These cases clearly demonstrate the lack of correlation between mtDNA value (Mitoscore and chromosomal status of embryo.

  20. X-Inactivation: Xist RNA Uses Chromosome Contacts to Coat the X

    OpenAIRE

    Leung, Karen N.; Panning, Barbara

    2014-01-01

    The mechanisms by which Xist RNA associates with the X chromosome to mediate alterations in chromatin structure remain mysterious. Recent genome-wide Xist RNA distribution studies suggest that this long noncoding RNA uses 3-dimensional chromosome contacts to move to its sites of action.

  1. X-inactivation: Xist RNA uses chromosome contacts to coat the X.

    Science.gov (United States)

    Leung, Karen N; Panning, Barbara

    2014-01-20

    The mechanisms by which Xist RNA associates with the X chromosome to mediate alterations in chromatin structure remain mysterious. Recent genome-wide Xist RNA distribution studies suggest that this long noncoding RNA uses 3-dimensional chromosome contacts to move to its sites of action. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. B chromosomes are more frequent in mammals with acrocentric karyotypes: support for the theory of centromeric drive.

    Science.gov (United States)

    Palestis, Brian G; Burt, Austin; Jones, R Neil; Trivers, Robert

    2004-02-07

    The chromosomes of mammals tend to be either mostly acrocentric (having one long arm) or mostly bi-armed, with few species having intermediate karyotypes. The theory of centromeric drive suggests that this observation reflects a bias during female meiosis, favouring either more centromeres or fewer, and that the direction of this bias changes frequently over evolutionary time. B chromosomes are selfish genetic elements found in some individuals within some species. B chromosomes are often harmful, but persist because they drive (i.e. they are transmitted more frequently than expected). We predicted that species with mainly acrocentric chromosomes would be more likely to harbour B chromosomes than those with mainly bi-armed chromosomes, because female meiosis would favour more centromeres over fewer in species with one-armed chromosomes. Our results show that B chromosomes are indeed more common in species with acrocentric chromosomes, across all mammals, among rodents, among non-rodents and in a test of independent taxonomic contrasts. These results provide independent evidence supporting the theory of centromeric drive and also help to explain the distribution of selfish DNA across species. In addition, we demonstrate an association between the shape of the B chromosomes and the shape of the typical ('A') chromosomes.

  3. Characterization of X chromosome inactivation using integrated analysis of whole-exome and mRNA sequencing.

    Directory of Open Access Journals (Sweden)

    Szabolcs Szelinger

    Full Text Available In females, X chromosome inactivation (XCI is an epigenetic, gene dosage compensatory mechanism by inactivation of one copy of X in cells. Random XCI of one of the parental chromosomes results in an approximately equal proportion of cells expressing alleles from either the maternally or paternally inherited active X, and is defined by the XCI ratio. Skewed XCI ratio is suggestive of non-random inactivation, which can play an important role in X-linked genetic conditions. Current methods rely on indirect, semi-quantitative DNA methylation-based assay to estimate XCI ratio. Here we report a direct approach to estimate XCI ratio by integrated, family-trio based whole-exome and mRNA sequencing using phase-by-transmission of alleles coupled with allele-specific expression analysis. We applied this method to in silico data and to a clinical patient with mild cognitive impairment but no clear diagnosis or understanding molecular mechanism underlying the phenotype. Simulation showed that phased and unphased heterozygous allele expression can be used to estimate XCI ratio. Segregation analysis of the patient's exome uncovered a de novo, interstitial, 1.7 Mb deletion on Xp22.31 that originated on the paternally inherited X and previously been associated with heterogeneous, neurological phenotype. Phased, allelic expression data suggested an 83∶20 moderately skewed XCI that favored the expression of the maternally inherited, cytogenetically normal X and suggested that the deleterious affect of the de novo event on the paternal copy may be offset by skewed XCI that favors expression of the wild-type X. This study shows the utility of integrated sequencing approach in XCI ratio estimation.

  4. X Chromosome Inactivation and Breast Cancer: Epigenetic Alteration in Tumor Initiation and Progression

    National Research Council Canada - National Science Library

    Panning, Barbara

    2007-01-01

    We tested whether reactivation of the inactive X chromosome in the mouse mammary gland contributes to tumorigenesis in vivo and whether that reactivation of the inactive X can cooperate with the MYC...

  5. Chromosome

    Science.gov (United States)

    ... St Louis, MO: Elsevier; 2017:chap 69. Taber's Medical Dictionary Online. Chromosome. www.tabers.com/tabersonline/view/Tabers-Dictionary/753321/all/chromosome?q=Chromosome&ti=0 . Accessed June 11, 2017.

  6. Stable X chromosome inactivation involves the PRC1 Polycomb complex and requires histone MACROH2A1 and the CULLIN3/SPOP ubiquitin E3 ligase

    DEFF Research Database (Denmark)

    Hernández-Muñoz, Inmaculada; Lund, Anders H; van der Stoop, Petra

    2005-01-01

    X inactivation involves the stable silencing of one of the two X chromosomes in XX female mammals. Initiation of this process occurs during early development and involves Xist (X-inactive-specific transcript) RNA coating and the recruitment of Polycomb repressive complex (PRC) 2 and PRC1 proteins...

  7. Skewed X-chromosome inactivation plays a crucial role in the onset of symptoms in carriers of Becker muscular dystrophy.

    Science.gov (United States)

    Viggiano, Emanuela; Picillo, Esther; Ergoli, Manuela; Cirillo, Alessandra; Del Gaudio, Stefania; Politano, Luisa

    2017-04-01

    Becker muscular dystrophy (BMD) is an X-linked recessive disorder affecting approximately 1: 18.000 male births. Female carriers are usually asymptomatic, although 2.5-18% may present muscle or heart symptoms. In the present study, the role of the X chromosome inactivation (XCI) on the onset of symptoms in BMD carriers was analysed and compared with the pattern observed in Duchenne muscular dystrophy (DMD) carriers. XCI was determined on the lymphocytes of 36 BMD carriers (both symptomatic and not symptomatic) from 11 families requiring genetic advice at the Cardiomyology and Medical Genetics of the Second University of Naples, using the AR methylation-based assay. Carriers were subdivided into two groups, according to age above or below 50 years. Seven females from the same families known as noncarriers were used as controls. A Student's t-test for nonpaired data was performed to evaluate the differences observed in the XCI values between asymptomatic and symptomatic carriers, and carriers aged above or below 50 years. A Pearson correlation test was used to evaluate the inheritance of the XCI pattern in 19 mother-daughter pairs. The results showed that symptomatic BMD carriers had a skewed XCI with a preferential inactivation of the X chromosome carrying the normal allele, whereas the asymptomatic carriers and controls showed a random XCI. No concordance concerning the XCI pattern was observed between mothers and related daughters. The data obtained in the present study suggest that the onset of symptoms in BMD carriers is related to a skewed XCI, as observed in DMD carriers. Furthermore, they showed no concordance in the XCI pattern inheritance. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Aberrant patterns of X chromosome inactivation in a new line of human embryonic stem cells established in physiological oxygen concentrations.

    Science.gov (United States)

    de Oliveira Georges, Juliana Andrea; Vergani, Naja; Fonseca, Simone Aparecida Siqueira; Fraga, Ana Maria; de Mello, Joana Carvalho Moreira; Albuquerque, Maria Cecília R Maciel; Fujihara, Litsuko Shimabukuro; Pereira, Lygia Veiga

    2014-08-01

    One of the differences between murine and human embryonic stem cells (ESCs) is the epigenetic state of the X chromosomes in female lines. Murine ESCs (mESCs) present two transcriptionally active Xs that will undergo the dosage compensation process of XCI upon differentiation, whereas most human ESCs (hESCs) spontaneously inactivate one X while keeping their pluripotency. Whether this reflects differences in embryonic development of mice and humans, or distinct culture requirements for the two kinds of pluripotent cells is not known. Recently it has been shown that hESCs established in physiological oxygen levels are in a stable pre-XCI state equivalent to that of mESCs, suggesting that culture in low oxygen concentration is enough to preserve that epigenetic state of the X chromosomes. Here we describe the establishment of two new lines of hESCs under physiological oxygen level and the characterization of the XCI state in the 46,XX line BR-5. We show that a fraction of undifferentiated cells present XIST RNA accumulation and single H3K27me foci, characteristic of the inactive X. Moreover, analysis of allele specific gene expression suggests that pluripotent BR-5 cells present completely skewed XCI. Our data indicate that physiological levels of oxygen are not sufficient for the stabilization of the pre-XCI state in hESCs.

  9. Skewed X-chromosome inactivation in female carriers of dyskeratosis congenita

    Energy Technology Data Exchange (ETDEWEB)

    Devriendt, K.; Matthijs, G.; Legius, E. [Univ. Hospital Gasthuisberg, Leuven (Belgium)] [and others

    1997-03-01

    In this study, we report on a family with X-linked dyskeratosis congenita (DC). Linkage analysis with markers in the factor VIII gene at Xq28 yielded a LOD score of 2 at a recombination of 0. Clinical manifestations of DC, such as skin lesions following the Blaschko lines, were present in two obligate carrier females. Highly skewed X inactivation was observed in white blood cells, cultured skin fibroblasts, and buccal mucosa from female carriers of DC in this family. This suggests a critical role for the DC gene in bone marrow-cell and fibroblast-cell proliferation. 23 refs., 4 figs., 1 tab.

  10. Sexual antagonism and meiotic drive cause stable linkage disequilibrium and favour reduced recombination on the X chromosome.

    Science.gov (United States)

    Rydzewski, W T; Carioscia, S A; Liévano, G; Lynch, V D; Patten, M M

    2016-06-01

    Sexual antagonism and meiotic drive are sex-specific evolutionary forces with the potential to shape genomic architecture. Previous theory has found that pairing two sexually antagonistic loci or combining sexual antagonism with meiotic drive at linked autosomal loci augments genetic variation, produces stable linkage disequilibrium (LD) and favours reduced recombination. However, the influence of these two forces has not been examined on the X chromosome, which is thought to be enriched for sexual antagonism and meiotic drive. We investigate the evolution of the X chromosome under both sexual antagonism and meiotic drive with two models: in one, both loci experience sexual antagonism; in the other, we pair a meiotic drive locus with a sexually antagonistic locus. We find that LD arises between the two loci in both models, even when the two loci freely recombine in females and that driving haplotypes will be enriched for male-beneficial alleles, further skewing sex ratios in these populations. We introduce a new measure of LD, Dz', which accounts for population allele frequencies and is appropriate for instances where these are sex specific. Both models demonstrate that natural selection favours modifiers that reduce the recombination rate. These results inform observed patterns of congealment found on driving X chromosomes and have implications for patterns of natural variation and the evolution of recombination rates on the X chromosome. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  11. Insertional inactivation of a chromosomal locus that modulates expression of potential virulence determinants in Staphylococcus aureus.

    OpenAIRE

    Cheung, A L; Wolz, C; Yeaman, M R; Bayer, A S

    1995-01-01

    A single insertion of transposon Tn551 into a unique chromosomal locus of Staphylococcus aureus ISP479C has resulted in a pleiotropic effect on the expression of both extracellular and cell wall proteins. In particular, the expression of cell wall protein A and clumping activity with fibrinogen were rendered undetectable in the mutant 1E3 compared with the parent. The secretion of alpha-hemolysin in mutant 1E3 was modestly increased. Southern blot and phenotypic analyses indicated that this l...

  12. Inactivation of the Escherichia coli chromosome during growth after ultraviolet irradiation

    International Nuclear Information System (INIS)

    Medic-Petranovic, M.; Trgovcevic, Z.; Novak, D.; Petranovic, D.

    1977-01-01

    Cells of the repair-proficient E.coli AB1157 strain and its lysogenic E.coli AB1157 (lambda c1857 ind) counterpart have been UV irradiated in an attempt to define when and why cells that are destined to die reach their biological end-point in the course of post-irradiation incubation. The thermo-inducibility of the lambdac1857 ind lysogens was first determined, since this reflects the functional integrity of the pro-viral part of the bacterial chromosome and that of the bacterial cytoplasm. The capacity (i.e. the ability of the irradiated cells to support growth of the unirradiated phage) was then determined, since this depends on the functional integrity of the bacterial cytoplasm. A progressive decrease in the ability of the lysogens to be heat-induced always preceded the decrease in capacity for the phage growth. The results strongly suggest that wild-type E.coli cells destined to die after exposure to moderate doses of UV-light reach their end point within 4 hours of post-irradiation incubation, probably as a result of the functional failure of the whole chromosome. (U.K.)

  13. Inactivation of the Escherichia coli chromosome during growth after ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Medic-Petranovic, M; Trgovcevic, Z; Novak, D; Petranovic, D [Institut Rudjer Boskovic, Zagreb (Yugoslavia)

    1977-07-01

    Cells of the repair-proficient E.coli AB1157 strain and its lysogenic E.coli AB1157 (lambda c1857 ind) counterpart have been uv irradiated in an attempt to define when and why cells that are destined to die reach their biological end-point in the course of post-irradiation incubation. The thermo-inducibility of the lambdac1857 ind lysogens was first determined, since this reflects the functional integrity of the pro-viral part of the bacterial chromosome and that of the bacterial cytoplasm. The capacity (i.e. the ability of the irradiated cells to support growth of the unirradiated phage) was then determined, since this depends on the functional integrity of the bacterial cytoplasm. A progressive decrease in the ability of the lysogens to be heat-induced always preceded the decrease in capacity for the phage growth. The results strongly suggest that wild-type E.coli cells destined to die after exposure to moderate doses of uv-light reach their end point within 4 hours of post-irradiation incubation, probably as a result of the functional failure of the whole chromosome.

  14. Female human pluripotent stem cells rapidly lose X chromosome inactivation marks and progress to a skewed methylation pattern during culture.

    Science.gov (United States)

    Geens, M; Seriola, A; Barbé, L; Santalo, J; Veiga, A; Dée, K; Van Haute, L; Sermon, K; Spits, C

    2016-04-01

    Does a preferential X chromosome inactivation (XCI) pattern exist in female human pluripotent stem cells (hPSCs) and does the pattern change during long-term culture or upon differentiation? We identified two independent phenomena that lead to aberrant XCI patterns in female hPSC: a rapid loss of histone H3 lysine 27 trimethylation (H3K27me3) and long non-coding X-inactive specific transcript (XIST) expression during culture, often accompanied by erosion of XCI-specific methylation, and a frequent loss of random XCI in the cultures. Variable XCI patterns have been reported in female hPSC, not only between different hPSC lines, but also between sub-passages of the same cell line, however the reasons for this variability remain unknown. Moreover, while non-random XCI-linked DNA methylation patterns have been previously reported, their origin and extent have not been investigated. We investigated the XCI patterns in 23 human pluripotent stem cell (hPSC) lines, during long-term culture and after differentiation, by gene expression analysis, histone modification assessment and study of DNA methylation. The presence and location of H3K27me3 was studied by immunofluorescence, XIST expression by real-time PCR, and mono- or bi-allelic expression of X-linked genes was studied by sequencing of cDNA. XCI-specific DNA methylation was analysed using methylation-sensitive restriction and PCR, and more in depth by massive parallel bisulphite sequencing. All hPSC lines showed XCI, but we found a rapid loss of XCI marks during the early stages of in vitro culture. While this loss of XCI marks was accompanied in several cases by an extensive erosion of XCI-specific methylation, it did not result in X chromosome reactivation. Moreover, lines without strong erosion of methylation frequently displayed non-random DNA methylation, which occurred independently from the loss of XCI marks. This bias in X chromosome DNA methylation did not appear as a passenger event driven by clonal culture

  15. A molecular switch driving inactivation in the cardiac K+ channel HERG.

    Directory of Open Access Journals (Sweden)

    David A Köpfer

    Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

  16. Determining the role of skewed X-chromosome inactivation in developing muscle symptoms in carriers of Duchenne muscular dystrophy.

    Science.gov (United States)

    Viggiano, Emanuela; Ergoli, Manuela; Picillo, Esther; Politano, Luisa

    2016-07-01

    Duchenne and Becker dystrophinopathies (DMD and BMD) are X-linked recessive disorders caused by mutations in the dystrophin gene that lead to absent or reduced expression of dystrophin in both skeletal and heart muscles. DMD/BMD female carriers are usually asymptomatic, although about 8 % may exhibit muscle or cardiac symptoms. Several mechanisms leading to a reduced dystrophin have been hypothesized to explain the clinical manifestations and, in particular, the role of the skewed XCI is questioned. In this review, the mechanism of XCI and its involvement in the phenotype of BMD/DMD carriers with both a normal karyotype or with X;autosome translocations with breakpoints at Xp21 (locus of the DMD gene) will be analyzed. We have previously observed that DMD carriers with moderate/severe muscle involvement, exhibit a moderate or extremely skewed XCI, in particular if presenting with an early onset of symptoms, while DMD carriers with mild muscle involvement present a random XCI. Moreover, we found that among 87.1 % of the carriers with X;autosome translocations involving the locus Xp21 who developed signs and symptoms of dystrophinopathy such as proximal muscle weakness, difficulty to run, jump and climb stairs, 95.2 % had a skewed XCI pattern in lymphocytes. These data support the hypothesis that skewed XCI is involved in the onset of phenotype in DMD carriers, the X chromosome carrying the normal DMD gene being preferentially inactivated and leading to a moderate-severe muscle involvement.

  17. Insertional inactivation of a chromosomal locus that modulates expression of potential virulence determinants in Staphylococcus aureus.

    Science.gov (United States)

    Cheung, A L; Wolz, C; Yeaman, M R; Bayer, A S

    1995-06-01

    A single insertion of transposon Tn551 into a unique chromosomal locus of Staphylococcus aureus ISP479C has resulted in a pleiotropic effect on the expression of both extracellular and cell wall proteins. In particular, the expression of cell wall protein A and clumping activity with fibrinogen were rendered undetectable in the mutant 1E3 compared with the parent. The secretion of alpha-hemolysin in mutant 1E3 was modestly increased. Southern blot and phenotypic analyses indicated that this locus is distinct from agr, xpr, and sar, three previously described global regulatory loci. Transduction experiments demonstrated that the genotype associated with mutant 1E3 could be transferred back into the parental strain ISP479C. The transductant 1E3-2 displayed a phenotypic profile similar to that of the original mutant. Northern (RNA) blot studies showed that this locus may be involved in modulating target genes at the mRNA level. In the rabbit endocarditis model, there was a significant decrease in both the infectivity rate and intravegetation bacterial density with mutant 1E3 compared with the parent at an inoculum of 10(3) CFU. Since protein A and the fibrinogen-binding protein(s) are major surface proteins that may mediate bacterial adhesion to host tissues, this locus may be an important genetic element involved in the expression of virulence determinants in S. aureus.

  18. ATPase Cycle of the Nonmotile Kinesin NOD Allows Microtubule End Tracking and Drives Chromosome Movement

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, J.; Sindelar, C; Mulko, N; Collins, K; Kong, S; Hawley, R; Kull, F

    2009-01-01

    Segregation of nonexchange chromosomes during Drosophila melanogaster meiosis requires the proper function of NOD, a nonmotile kinesin-10. We have determined the X-ray crystal structure of the NOD catalytic domain in the ADP- and AMPPNP-bound states. These structures reveal an alternate conformation of the microtubule binding region as well as a nucleotide-sensitive relay of hydrogen bonds at the active site. Additionally, a cryo-electron microscopy reconstruction of the nucleotide-free microtubule-NOD complex shows an atypical binding orientation. Thermodynamic studies show that NOD binds tightly to microtubules in the nucleotide-free state, yet other nucleotide states, including AMPPNP, are weakened. Our pre-steady-state kinetic analysis demonstrates that NOD interaction with microtubules occurs slowly with weak activation of ADP product release. Upon rapid substrate binding, NOD detaches from the microtubule prior to the rate-limiting step of ATP hydrolysis, which is also atypical for a kinesin. We propose a model for NOD's microtubule plus-end tracking that drives chromosome movement.

  19. Human X-chromosome inactivation pattern distributions fit a model of genetically influenced choice better than models of completely random choice

    Science.gov (United States)

    Renault, Nisa K E; Pritchett, Sonja M; Howell, Robin E; Greer, Wenda L; Sapienza, Carmen; Ørstavik, Karen Helene; Hamilton, David C

    2013-01-01

    In eutherian mammals, one X-chromosome in every XX somatic cell is transcriptionally silenced through the process of X-chromosome inactivation (XCI). Females are thus functional mosaics, where some cells express genes from the paternal X, and the others from the maternal X. The relative abundance of the two cell populations (X-inactivation pattern, XIP) can have significant medical implications for some females. In mice, the ‘choice' of which X to inactivate, maternal or paternal, in each cell of the early embryo is genetically influenced. In humans, the timing of XCI choice and whether choice occurs completely randomly or under a genetic influence is debated. Here, we explore these questions by analysing the distribution of XIPs in large populations of normal females. Models were generated to predict XIP distributions resulting from completely random or genetically influenced choice. Each model describes the discrete primary distribution at the onset of XCI, and the continuous secondary distribution accounting for changes to the XIP as a result of development and ageing. Statistical methods are used to compare models with empirical data from Danish and Utah populations. A rigorous data treatment strategy maximises information content and allows for unbiased use of unphased XIP data. The Anderson–Darling goodness-of-fit statistics and likelihood ratio tests indicate that a model of genetically influenced XCI choice better fits the empirical data than models of completely random choice. PMID:23652377

  20. Apc inactivation, but not obesity, synergizes with Pten deficiency to drive intestinal stem cell-derived tumorigenesis.

    Science.gov (United States)

    Tabrizian, Tahmineh; Wang, Donghai; Guan, Fangxia; Hu, Zunju; Beck, Amanda P; Delahaye, Fabien; Huffman, Derek M

    2017-06-01

    Obesity is a major risk factor for colorectal cancer and can accelerate Lgr5+ intestinal stem cell (ISC)-derived tumorigenesis after the inactivation of Apc However, whether non-canonical pathways involving PI3K-Akt signaling in ISCs can lead to tumor formation, and if this can be further exacerbated by obesity is unknown. Despite the synergy between Pten and Apc inactivation in epithelial cells on intestinal tumor formation, their combined role in Lgr5+-ISCs, which are the most rapidly dividing ISC population in the intestine, is unknown. Lgr5+-GFP mice were provided low-fat diet (LFD) or high-fat diet (HFD) for 8 months, and the transcriptome was evaluated in Lgr5+-ISCs. For tumor studies, Lgr5+-GFP and Lgr5+-GFP- Pten flox/flox mice were tamoxifen treated to inactivate Pten in ISCs and provided LFD or HFD until 14-15 months of age. Finally, various combinations of Lgr5+-ISC-specific, Apc- and Pten -deleted mice were generated and evaluated for histopathology and survival. HFD did not overtly alter Akt signaling in ISCs, but did increase other metabolic pathways. Pten deficiency, but not HFD, increased BrdU-positive cells in the small intestine ( P  Apc deficiency synergistically increased proliferative markers, tumor pathology and mortality, in a dose-dependent fashion ( P  Apc deficiency in ISCs synergistically increases proliferation, tumor formation and mortality. Thus, aberrant Wnt/β-catenin, rather than PI3K-Akt signaling, is requisite for obesity to drive Lgr5+ ISC-derived tumorigenesis. © 2017 Society for Endocrinology.

  1. Modeling Renal Cell Carcinoma in Mice: Bap1 and Pbrm1 Inactivation Drive Tumor Grade.

    Science.gov (United States)

    Gu, Yi-Feng; Cohn, Shannon; Christie, Alana; McKenzie, Tiffani; Wolff, Nicholas; Do, Quyen N; Madhuranthakam, Ananth J; Pedrosa, Ivan; Wang, Tao; Dey, Anwesha; Busslinger, Meinrad; Xie, Xian-Jin; Hammer, Robert E; McKay, Renée M; Kapur, Payal; Brugarolas, James

    2017-08-01

    Clear cell renal cell carcinoma (ccRCC) is characterized by BAP1 and PBRM1 mutations, which are associated with tumors of different grade and prognosis. However, whether BAP1 and PBRM1 loss causes ccRCC and determines tumor grade is unclear. We conditionally targeted Bap1 and Pbrm1 (with Vhl ) in the mouse using several Cre drivers. Sglt2 and Villin proximal convoluted tubule drivers failed to cause tumorigenesis, challenging the conventional notion of ccRCC origins. In contrast, targeting with PAX8, a transcription factor frequently overexpressed in ccRCC, led to ccRCC of different grades. Bap1 -deficient tumors were of high grade and showed greater mTORC1 activation than Pbrm1 -deficient tumors, which exhibited longer latency. Disrupting one allele of the mTORC1 negative regulator, Tsc1 , in Pbrm1 -deficient kidneys triggered higher grade ccRCC. This study establishes Bap1 and Pbrm1 as lineage-specific drivers of ccRCC and histologic grade, implicates mTORC1 as a tumor grade rheostat, and suggests that ccRCCs arise from Bowman capsule cells. Significance: Determinants of tumor grade and aggressiveness across cancer types are poorly understood. Using ccRCC as a model, we show that Bap1 and Pbrm1 loss drives tumor grade. Furthermore, we show that the conversion from low grade to high grade can be promoted by activation of mTORC1. Cancer Discov; 7(8); 900-17. ©2017 AACR. See related commentary by Leung and Kim, p. 802 This article is highlighted in the In This Issue feature, p. 783 . ©2017 American Association for Cancer Research.

  2. Absence of positive selection on CenH3 in Luzula suggests that holokinetic chromosomes may suppress centromere drive.

    Science.gov (United States)

    Zedek, František; Bureš, Petr

    2016-12-01

    The centromere drive theory explains diversity of eukaryotic centromeres as a consequence of the recurrent conflict between centromeric repeats and centromeric histone H3 (CenH3), in which selfish centromeres exploit meiotic asymmetry and CenH3 evolves adaptively to counterbalance deleterious consequences of driving centromeres. Accordingly, adaptively evolving CenH3 has so far been observed only in eukaryotes with asymmetric meiosis. However, if such evolution is a consequence of centromere drive, it should depend not only on meiotic asymmetry but also on monocentric or holokinetic chromosomal structure. Selective pressures acting on CenH3 have never been investigated in organisms with holokinetic meiosis despite the fact that holokinetic chromosomes have been hypothesized to suppress centromere drive. Therefore, the present study evaluates selective pressures acting on the CenH3 gene in holokinetic organisms for the first time, specifically in the representatives of the plant genus Luzula (Juncaceae), in which the kinetochore formation is not co-localized with any type of centromeric repeat. PCR, cloning and sequencing, and database searches were used to obtain coding CenH3 sequences from Luzula species. Codon substitution models were employed to infer selective regimes acting on CenH3 in Luzula KEY RESULTS: In addition to the two previously published CenH3 sequences from L. nivea, 16 new CenH3 sequences have been isolated from 12 Luzula species. Two CenH3 isoforms in Luzula that originated by a duplication event prior to the divergence of analysed species were found. No signs of positive selection acting on CenH3 in Luzula were detected. Instead, evidence was found that selection on CenH3 of Luzula might have been relaxed. The results indicate that holokinetism itself may suppress centromere drive and, therefore, holokinetic chromosomes might have evolved as a defence against centromere drive. © The Author 2016. Published by Oxford University Press on behalf of

  3. Cell inactivation and chromosomal aberrations induced by X-rays and fast neutrons in cells of the Chinese hamster. 1

    International Nuclear Information System (INIS)

    Tolkendorf, E.

    1979-01-01

    Asynchronously grown cultures of Chinese hamster cells V79-4 were irradiated in suspension with 180 kV X-rays and fast neutrons (average energy of 6.2 MeV). The damage was assessed by measuring cell survival and frequencies of chromosome aberrations in the first post-irradiation metaphases. The experimental data for survival and chromosome aberrations were fitted by computer programmes. From the fitted curves the relative biological effectiveness (RBE) of fast neutrons was calculated. The RBE shows a similar dose dependence for killed and aberrant cells. The RBE decreases with increasing dose and amounts to approximately 5 for both effects for small neutron doses. The highest RBE is found for asymmetrical chromosomal exchanges and is dependent on the neutron dose, too. However, for isochromatid deletions the RBE is dose independent with a value of 3.6. (author)

  4. Sequential actin-based pushing forces drive meiosis I chromosome migration and symmetry breaking in oocytes

    Science.gov (United States)

    Yi, Kexi; Rubinstein, Boris; Unruh, Jay R.; Guo, Fengli; Slaughter, Brian D.

    2013-01-01

    Polar body extrusion during oocyte maturation is critically dependent on asymmetric positioning of the meiotic spindle, which is established through migration of the meiosis I (MI) spindle/chromosomes from the oocyte interior to a subcortical location. In this study, we show that MI chromosome migration is biphasic and driven by consecutive actin-based pushing forces regulated by two actin nucleators, Fmn2, a formin family protein, and the Arp2/3 complex. Fmn2 was recruited to endoplasmic reticulum structures surrounding the MI spindle, where it nucleated actin filaments to initiate an initially slow and poorly directed motion of the spindle away from the cell center. A fast and highly directed second migration phase was driven by actin-mediated cytoplasmic streaming and occurred as the chromosomes reach a sufficient proximity to the cortex to activate the Arp2/3 complex. We propose that decisive symmetry breaking in mouse oocytes results from Fmn2-mediated perturbation of spindle position and the positive feedback loop between chromosome signal-induced Arp2/3 activation and Arp2/3-orchestrated cytoplasmic streaming that transports the chromosomes. PMID:23439682

  5. X-chromosome inactivation patterns in monozygotic twins and sib pairs discordant for nonsyndromic cleft lip and/or palate

    DEFF Research Database (Denmark)

    Kimani, Jane W; Shi, Min; Daack-Hirsch, Sandra

    2007-01-01

    Nonsyndromic clefts of the lip and/or palate are common birth defects with a strong genetic component. Based on unequal gender ratios for clefting phenotypes, evidence for linkage to the X chromosome and the occurrence of several X-linked clefting syndromes, we investigated the role of skewed X c...

  6. Multiple sex chromosomes in the light of female meiotic drive in amniote vertebrates

    Czech Academy of Sciences Publication Activity Database

    Pokorná, Martina; Altmanová, M.; Kratochvíl, L.

    2014-01-01

    Roč. 22, č. 1 (2014), s. 35-44 ISSN 0967-3849 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : amniota * centromere * heterogamety * neo-sex chromosomes * reptiles Subject RIV: EG - Zoology Impact factor: 2.478, year: 2014

  7. Tripolar chromosome segregation drives the association between maternal genotype at variants spanning PLK4 and aneuploidy in human preimplantation embryos.

    Science.gov (United States)

    McCoy, Rajiv C; Newnham, Louise J; Ottolini, Christian S; Hoffmann, Eva R; Chatzimeletiou, Katerina; Cornejo, Omar E; Zhan, Qiansheng; Zaninovic, Nikica; Rosenwaks, Zev; Petrov, Dmitri A; Demko, Zachary P; Sigurjonsson, Styrmir; Handyside, Alan H

    2018-04-24

    Aneuploidy is prevalent in human embryos and is the leading cause of pregnancy loss. Many aneuploidies arise during oogenesis, increasing with maternal age. Superimposed on these meiotic aneuploidies are frequent errors occurring during early mitotic divisions, contributing to widespread chromosomal mosaicism. Here we reanalyzed a published dataset comprising preimplantation genetic testing for aneuploidy in 24,653 blastomere biopsies from day-3 cleavage-stage embryos, as well as 17,051 trophectoderm biopsies from day-5 blastocysts. We focused on complex abnormalities that affected multiple chromosomes simultaneously, seeking insights into their formation. In addition to well-described patterns such as triploidy and haploidy, we identified 4.7% of blastomeres possessing characteristic hypodiploid karyotypes. We inferred this signature to have arisen from tripolar chromosome segregation in normally-fertilized diploid zygotes or their descendant diploid cells. This could occur via segregation on a tripolar mitotic spindle or by rapid sequential bipolar mitoses without an intervening S-phase. Both models are consistent with time-lapse data from an intersecting set of 77 cleavage-stage embryos, which were enriched for the tripolar signature among embryos exhibiting abnormal cleavage. The tripolar signature was strongly associated with common maternal genetic variants spanning the centrosomal regulator PLK4, driving the association we previously reported with overall mitotic errors. Our findings are consistent with the known capacity of PLK4 to induce tripolar mitosis or precocious M-phase upon dysregulation. Together, our data support tripolar chromosome segregation as a key mechanism generating complex aneuploidy in cleavage-stage embryos and implicate maternal genotype at a quantitative trait locus spanning PLK4 as a factor influencing its occurrence.

  8. 5meCpG epigenetic marks neighboring a primate-conserved core promoter short tandem repeat indicate X-chromosome inactivation.

    Science.gov (United States)

    Machado, Filipe Brum; Machado, Fabricio Brum; Faria, Milena Amendro; Lovatel, Viviane Lamim; Alves da Silva, Antonio Francisco; Radic, Claudia Pamela; De Brasi, Carlos Daniel; Rios, Álvaro Fabricio Lopes; de Sousa Lopes, Susana Marina Chuva; da Silveira, Leonardo Serafim; Ruiz-Miranda, Carlos Ramon; Ramos, Ester Silveira; Medina-Acosta, Enrique

    2014-01-01

    X-chromosome inactivation (XCI) is the epigenetic transcriptional silencing of an X-chromosome during the early stages of embryonic development in female eutherian mammals. XCI assures monoallelic expression in each cell and compensation for dosage-sensitive X-linked genes between females (XX) and males (XY). DNA methylation at the carbon-5 position of the cytosine pyrimidine ring in the context of a CpG dinucleotide sequence (5meCpG) in promoter regions is a key epigenetic marker for transcriptional gene silencing. Using computational analysis, we revealed an extragenic tandem GAAA repeat 230-bp from the landmark CpG island of the human X-linked retinitis pigmentosa 2 RP2 promoter whose 5meCpG status correlates with XCI. We used this RP2 onshore tandem GAAA repeat to develop an allele-specific 5meCpG-based PCR assay that is highly concordant with the human androgen receptor (AR) exonic tandem CAG repeat-based standard HUMARA assay in discriminating active (Xa) from inactive (Xi) X-chromosomes. The RP2 onshore tandem GAAA repeat contains neutral features that are lacking in the AR disease-linked tandem CAG repeat, is highly polymorphic (heterozygosity rates approximately 0.8) and shows minimal variation in the Xa/Xi ratio. The combined informativeness of RP2/AR is approximately 0.97, and this assay excels at determining the 5meCpG status of alleles at the Xp (RP2) and Xq (AR) chromosome arms in a single reaction. These findings are relevant and directly translatable to nonhuman primate models of XCI in which the AR CAG-repeat is monomorphic. We conducted the RP2 onshore tandem GAAA repeat assay in the naturally occurring chimeric New World monkey marmoset (Callitrichidae) and found it to be informative. The RP2 onshore tandem GAAA repeat will facilitate studies on the variable phenotypic expression of dominant and recessive X-linked diseases, epigenetic changes in twins, the physiology of aging hematopoiesis, the pathogenesis of age-related hematopoietic

  9. 5meCpG epigenetic marks neighboring a primate-conserved core promoter short tandem repeat indicate X-chromosome inactivation.

    Directory of Open Access Journals (Sweden)

    Filipe Brum Machado

    Full Text Available X-chromosome inactivation (XCI is the epigenetic transcriptional silencing of an X-chromosome during the early stages of embryonic development in female eutherian mammals. XCI assures monoallelic expression in each cell and compensation for dosage-sensitive X-linked genes between females (XX and males (XY. DNA methylation at the carbon-5 position of the cytosine pyrimidine ring in the context of a CpG dinucleotide sequence (5meCpG in promoter regions is a key epigenetic marker for transcriptional gene silencing. Using computational analysis, we revealed an extragenic tandem GAAA repeat 230-bp from the landmark CpG island of the human X-linked retinitis pigmentosa 2 RP2 promoter whose 5meCpG status correlates with XCI. We used this RP2 onshore tandem GAAA repeat to develop an allele-specific 5meCpG-based PCR assay that is highly concordant with the human androgen receptor (AR exonic tandem CAG repeat-based standard HUMARA assay in discriminating active (Xa from inactive (Xi X-chromosomes. The RP2 onshore tandem GAAA repeat contains neutral features that are lacking in the AR disease-linked tandem CAG repeat, is highly polymorphic (heterozygosity rates approximately 0.8 and shows minimal variation in the Xa/Xi ratio. The combined informativeness of RP2/AR is approximately 0.97, and this assay excels at determining the 5meCpG status of alleles at the Xp (RP2 and Xq (AR chromosome arms in a single reaction. These findings are relevant and directly translatable to nonhuman primate models of XCI in which the AR CAG-repeat is monomorphic. We conducted the RP2 onshore tandem GAAA repeat assay in the naturally occurring chimeric New World monkey marmoset (Callitrichidae and found it to be informative. The RP2 onshore tandem GAAA repeat will facilitate studies on the variable phenotypic expression of dominant and recessive X-linked diseases, epigenetic changes in twins, the physiology of aging hematopoiesis, the pathogenesis of age-related hematopoietic

  10. A new macro-micro dual drive parallel robot for chromosome dissection

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jin; Gao, Feng; Zhao, Xianchao; Yue, Yi; Liu, Renqiang [Shanghai Jiao Tong University, Shanghai (China)

    2012-01-15

    This paper presents a parallel-structure system dually driven by six servo motors and six piezoelectric actuators. Due to the combination of macro and micro manipulators which are both of orthogonal structures, the proposed system possesses a concise structure as well as actuation isolation and output motion decoupling properties. By using a glass needle mounted on a six-dimensional force sensor in endpoint operating, this system can be applied to chromosome dissection that to make the whole process more efficient and automatic. The glass needle tip has a stroke of 106 mm in three linear motions and 18.7-arc-degrees in three angle motion directions, with servo motors adopted. It also has the resolution of 20 nanometers with the adoption of piezoelectric actuators. The kinematics, isotropy, decoupling and design considerations of the proposed robot are discussed. Workspace and resolution of both macro and micro manipulators are measured separately. The experiments are also conducted to show its capability in dissecting chromosomes.

  11. Enrichment of dynamic chromosomal crosslinks drive phase separation of the nucleolus.

    Science.gov (United States)

    Hult, Caitlin; Adalsteinsson, David; Vasquez, Paula A; Lawrimore, Josh; Bennett, Maggie; York, Alyssa; Cook, Diana; Yeh, Elaine; Forest, Mark Gregory; Bloom, Kerry

    2017-11-02

    Regions of highly repetitive DNA, such as those found in the nucleolus, show a self-organization that is marked by spatial segregation and frequent self-interaction. The mechanisms that underlie the sequestration of these sub-domains are largely unknown. Using a stochastic, bead-spring representation of chromatin in budding yeast, we find enrichment of protein-mediated, dynamic chromosomal cross-links recapitulates the segregation, morphology and self-interaction of the nucleolus. Rates and enrichment of dynamic crosslinking have profound consequences on domain morphology. Our model demonstrates the nucleolus is phase separated from other chromatin in the nucleus and predicts that multiple rDNA loci will form a single nucleolus independent of their location within the genome. Fluorescent labeling of budding yeast nucleoli with CDC14-GFP revealed that a split rDNA locus indeed forms a single nucleolus. We propose that nuclear sub-domains, such as the nucleolus, result from phase separations within the nucleus, which are driven by the enrichment of protein-mediated, dynamic chromosomal crosslinks. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. Inactivation of the P16INK4/MTS1 gene by a chromosome translocation t(9;14)(p21-22;q11) in an acute lymphoblastic leukemia of B-cell type.

    Science.gov (United States)

    Duro, D; Bernard, O; Della Valle, V; Leblanc, T; Berger, R; Larsen, C J

    1996-02-15

    We have reported previously a preliminary study of a t(9;14)(p21-22; q11) in B-cell acute lymphoblastic leukemia. This translocation had rearranged the TCRA/D locus on chromosome band 14q11 and the locus encoding the tumor suppressor gene P16INK4/MTS1 (P16) on band 9p21 (D. Duro et al., Oncogene, 11: 21-29, 1995). In the present report, the breakpoints were precisely localized on each chromosome partner. On the 14q- derivative, the sequence derived from chromosome 9 was interrupted at 1.0 kb upstream of the first exon of P16, close to a consensus recombination heptamer, CACTGTG. In addition, the chromosome 14 breakpoint was localized at the end of the TCRD2 (delta 2) segment, and 22 residues with unknown origin were present at the translocation junction. On the 9p+ derivative, chromosome 9 sequences were in continuity with those displaced onto chromosome 14, and the 14q11 breakpoint was located within TCRJA29 segment. These features are consistent with aberrant activity of the TCR gene recombinase complex. Although all three coding exons of P16 were displaced onto the chromosome 14q-derivative, no P16 transcript was detected in the leukemic cells. Because the region spanning the P16 exon 1 was not inactivated by methylation and because the other P16 allele was deleted, the implication is that the chromosome breakpoint was likely to disrupt regulatory elements involved in the normal expression of the gene. As a whole, then, our results show that translocations affecting band 9p21 can participate to the inactivation of P16, thus justifying a systematic survey of translocations of the 9p21 band in acute lymphoblastic leukemia.

  13. Use of X-Chromosome Inactivation Pattern to Analyze the Clonality of 14 Female Cases of Kaposi Sarcoma.

    Science.gov (United States)

    Yuan, Ding; XiuJuan, Wu; Yan, Zhang; JunQin, Liang; Fang, Xiang; Shirong, Yu; Xiaojing, Kang; Yanyan, Feng; Weidong, Wu; Dong, Luo; Qingli, Lu; DeZhi, Zhang; XiongMing, Pu

    2015-06-16

    Kaposi sarcoma (KS) has features of both neoplastic growth and hyperplastic proliferation. It is the most common tumor seen in patients with HIV infection. Whether KS is a real tumor or a benign hyperplastic disease is not known. Tissues from KS and cutaneous hemangioma lesion DNA were extracted, and then digested with methylation-sensitive restriction endonuclease HpaII. Human androgen receptor gene (HUMARA) was amplified with PCR method and the product was separated on 10% denaturing polyacrylamide gels and stained with ethylene dibromide (EB) to show the polymorphism of HUMARA. Phosphoglycerate kinase (PGK) was amplified and the product was digested by BStXI, agarose gel and EB stained to show the polymorphism of PGK. Finally, we analyzed the clonality of KS. In the 14 patients with KS, heterozygosity of the HUMARA gene was observed in 12 (85.7%) cases. Loss of heterozygosity of HUMARA gene on X-chromosome (without HpaII digestion there were 2 bands, after HpaII digestion there were just 1 of the bands), representing monoclonal origin, was present in 11 cases of Kaposi sarcoma. Heterozygosity of the PGK gene was observed in 5 (35.7%) cases, which all represent monoclonal origin. There was no significant difference according to country, stage, or HIV and HHV-8 (P>0.05). The current findings suggest that Kaposi sarcoma is a clonal neoplasm, not a reactive proliferation.

  14. Cellular and subcellular effect of heavy ions: A comparison of the induction of strand breaks and chromosomal aberration with the incidence of inactivation and mutation

    International Nuclear Information System (INIS)

    Kraft, G.; Kraft-Weyrather, W.; Ritter, S.; Scholz, M.; Stanton, J.

    1988-10-01

    Radiobiological effects of heavy charged particles are compared for a large variety of ions from Helium to Uranium and energies between 1 and 1000 MeV/u which correspond to LET values between 10 and 16000 keV/μm. The different cross section for the induction of strand breaks and chromosomal aberrations as well as for inactivation and mutation induction exhibit striking similarities when compared as function of the linear energy transfer (LET). At LET values below 100 keV/μm all data points of one specific effect form one single curve as a function of LET, independent of the atomic number of the ion. In this LET range, the biological effects are independent from the particle energy or track structure and depend only on the energy transfer. Therefore, LET is a good parameter in tis regime. For LET values greater than 100 keV/μm, the curves for the different ions separate from the common curve in order of increasing atomic numbers. In this regime LET is no longer a good parameter and the physical parameters of the formation of particle tracks are important. The similarity of the σ-LET curves for different endpoints indicates that the 'hook-structure' is produced by physical and chemical effects which occur before the biologically relevant lesions are formed. However, from the existing data of biological effects, it can be concluded that the efficiencies for cell killing are always smaller than those extrapolated from X-ray data on the basis of the energy deposition only. Therefore, cells which are directly hit by an HZE particle are not killed and undergo a finite risk of mutation and transformation. (orig.)

  15. Peripheral drive in Aα/β-fiber neurons is altered in a rat model of osteoarthritis: changes in following frequency and recovery from inactivation

    Directory of Open Access Journals (Sweden)

    Wu Q

    2013-03-01

    Full Text Available Qi Wu, James L HenryDepartment of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, CanadaPurpose: To determine conduction fidelity of Aα/β-fiber low threshold mechanoreceptors in a model of osteoarthritis (OA.Methods: Four weeks after cutting the anterior cruciate ligament and removing the medial meniscus to induce the model, in vivo intracellular recordings were made in ipsilateral L4 dorsal root ganglion neurons. L4 dorsal roots were stimulated to determine the refractory interval and the maximum following frequency of the evoked action potential (AP. Neurons exhibited two types of response to paired pulse stimulation. Results: One type of response was characterized by fractionation of the evoked AP into an initial nonmyelinated-spike and a later larger-amplitude somatic-spike at shorter interstimulus intervals. The other type of response was characterized by an all-or-none AP, where the second evoked AP failed altogether at shorter interstimulus intervals. In OA versus control animals, the refractory interval measured in paired pulse testing was less in all low threshold mechanoreceptors. With train stimulation, the maximum rising rate of the nonmyelinated-spike was greater in OA nonmuscle spindle low threshold mechanoreceptors, possibly due to changes in fast kinetics of currents. Maximum following frequency in Pacinian and muscle spindle neurons was greater in model animals compared to controls. Train stimulation also induced an inactivation and fractionation of the AP in neurons that showed fractionation of the AP in paired pulse testing. However, with train stimulation this fractionation followed a different time course, suggesting more than one type of inactivation.Conclusion: The data suggest that joint damage can lead to changes in the fidelity of AP conduction of large diameter sensory neurons, muscle spindle neurons in particular, arising from articular and nonarticular tissues in OA animals compared to

  16. Hda-mediated inactivation of the DnaA protein and dnaA gene autoregulation act in concert to ensure homeostatic maintenance of the Escherichia coli chromosome.

    Science.gov (United States)

    Riber, Leise; Olsson, Jan A; Jensen, Rasmus B; Skovgaard, Ole; Dasgupta, Santanu; Marinus, Martin G; Løbner-Olesen, Anders

    2006-08-01

    Initiation of DNA replication in Eschericia coli requires the ATP-bound form of the DnaA protein. The conversion of DnaA-ATP to DnaA-ADP is facilitated by a complex of DnaA, Hda (homologous to DnaA), and DNA-loaded beta-clamp proteins in a process termed RIDA (regulatory inactivation of DnaA). Hda-deficient cells initiate replication at each origin mainly once per cell cycle, and the rare reinitiation events never coincide with the end of the origin sequestration period. Therefore, RIDA is not the predominant mechanism to prevent immediate reinitiation from oriC. The cellular level of Hda correlated directly with dnaA gene expression such that Hda deficiency led to reduced dnaA gene expression, and overproduction of Hda led to DnaA overproduction. Hda-deficient cells were very sensitive to variations in the cellular level of DnaA, and DnaA overproduction led to uncontrolled initiation of replication from oriC, causing severe growth retardation or cell death. Based on these observations, we propose that both RIDA and dnaA gene autoregulation are required as homeostatic mechanisms to ensure that initiation of replication occurs at the same time relative to cell mass in each cell cycle.

  17. Xist RNA is confined to the nuclear territory of the silenced X chromosome throughout the cell cycle

    NARCIS (Netherlands)

    I.H. Jonkers (Iris); K. Monkhorst (Kim); E. Rentmeester (Eveline); J.A. Grootegoed (Anton); F.G. Grosveld (Frank); J.H. Gribnau (Joost)

    2008-01-01

    textabstractIn mammalian female cells, one X chromosome is inactivated to prevent a dose difference in the expression of X-encoded proteins between males and females. Xist RNA, required for X chromosome inactivation, is transcribed from the future inactivated X chromosome (Xi), where it spreads in

  18. The X chromosome in space.

    Science.gov (United States)

    Jégu, Teddy; Aeby, Eric; Lee, Jeannie T

    2017-06-01

    Extensive 3D folding is required to package a genome into the tiny nuclear space, and this packaging must be compatible with proper gene expression. Thus, in the well-hierarchized nucleus, chromosomes occupy discrete territories and adopt specific 3D organizational structures that facilitate interactions between regulatory elements for gene expression. The mammalian X chromosome exemplifies this structure-function relationship. Recent studies have shown that, upon X-chromosome inactivation, active and inactive X chromosomes localize to different subnuclear positions and adopt distinct chromosomal architectures that reflect their activity states. Here, we review the roles of long non-coding RNAs, chromosomal organizational structures and the subnuclear localization of chromosomes as they relate to X-linked gene expression.

  19. Metastic Progression of Breast Cancer by Allelic Loss on Chromosome 18q21

    National Research Council Canada - National Science Library

    Thiagalingam, Sam

    2006-01-01

    Genetic and epigenetic inactivation of SMAD4 are rare occurrences in breast tumors despite it is localized to chromosome 18q and serves as a frequent target for inactivation in advanced gastrointestinal cancers...

  20. Increased high-density lipoprotein cholesterol levels in mice with XX versus XY sex chromosomes.

    Science.gov (United States)

    Link, Jenny C; Chen, Xuqi; Prien, Christopher; Borja, Mark S; Hammerson, Bradley; Oda, Michael N; Arnold, Arthur P; Reue, Karen

    2015-08-01

    The molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels. We assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the four core genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male-female gonadal sex and XX-XY chromosome complement. Gonadectomy of adult mice revealed that the male-female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male-female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared with a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with 2 X chromosomes compared with mice with an X and Y chromosome. By generating mice with XX, XY, and XXY chromosome complements, we determined that the presence of 2 X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration. We demonstrate that having 2 X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels. © 2015 American Heart Association, Inc.

  1. Skewed X-inactivation in cloned mice

    International Nuclear Information System (INIS)

    Senda, Sho; Wakayama, Teruhiko; Yamazaki, Yukiko; Ohgane, Jun; Hattori, Naka; Tanaka, Satoshi; Yanagimachi, Ryuzo; Shiota, Kunio

    2004-01-01

    In female mammals, dosage compensation for X-linked genes is accomplished by inactivation of one of two X chromosomes. The X-inactivation ratio (a percentage of the cells with inactivated maternal X chromosomes in the whole cells) is skewed as a consequence of various genetic mutations, and has been observed in a number of X-linked disorders. We previously reported that phenotypically normal full-term cloned mouse fetuses had loci with inappropriate DNA methylation. Thus, cloned mice are excellent models to study abnormal epigenetic events in mammalian development. In the present study, we analyzed X-inactivation ratios in adult female cloned mice (B6C3F1). Kidneys of eight naturally produced controls and 11 cloned mice were analyzed. Although variations in X-inactivation ratio among the mice were observed in both groups, the distributions were significantly different (Ansary-Bradley test, P < 0.01). In particular, 2 of 11 cloned mice showed skewed X-inactivation ratios (19.2% and 86.8%). Similarly, in intestine, 1 of 10 cloned mice had a skewed ratio (75.7%). Skewed X-inactivation was observed to various degrees in different tissues of different individuals, suggesting that skewed X-inactivation in cloned mice is the result of secondary cell selection in combination with stochastic distortion of primary choice. The present study is the first demonstration that skewed X-inactivation occurs in cloned animals. This finding is important for understanding both nuclear transfer technology and etiology of X-linked disorders

  2. X Inactivation and Progenitor Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ruben Agrelo

    2011-04-01

    Full Text Available In mammals, silencing of one of the two X chromosomes is necessary to achieve dosage compensation. The 17 kb non-coding RNA called Xist triggers X inactivation. Gene silencing by Xist can only be achieved in certain contexts such as in cells of the early embryo and in certain hematopoietic progenitors where silencing factors are present. Moreover, these epigenetic contexts are maintained in cancer progenitors in which SATB1 has been identified as a factor related to Xist-mediated chromosome silencing.

  3. Inactivation Data.xlsx

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data set is a spreadsheet that contains results of inactivation experiments that were conducted to to determine the effectiveness of chlorine in inactivating B....

  4. Modeling Chromosomes

    Science.gov (United States)

    Robertson, Carol

    2016-01-01

    Learning about chromosomes is standard fare in biology classrooms today. However, students may find it difficult to understand the relationships among the "genome", "chromosomes", "genes", a "gene locus", and "alleles". In the simple activity described in this article, which follows the 5E approach…

  5. Chromosomal Conditions

    Science.gov (United States)

    ... and more. Stony Point, NY 10980 Close X Home > Complications & Loss > Birth defects & other health conditions > Chromosomal conditions Chromosomal conditions ... Disorders See also: Genetic counseling , Your family health history Last reviewed: February, 2013 ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & ...

  6. Inactivation of Caliciviruses

    Directory of Open Access Journals (Sweden)

    Raymond Nims

    2013-03-01

    Full Text Available The Caliciviridae family of viruses contains clinically important human and animal pathogens, as well as vesivirus 2117, a known contaminant of biopharmaceutical manufacturing processes employing Chinese hamster cells. An extensive literature exists for inactivation of various animal caliciviruses, especially feline calicivirus and murine norovirus. The caliciviruses are susceptible to wet heat inactivation at temperatures in excess of 60 °C with contact times of 30 min or greater, to UV-C inactivation at fluence ≥30 mJ/cm2, to high pressure processing >200 MPa for >5 min at 4 °C, and to certain photodynamic inactivation approaches. The enteric caliciviruses (e.g.; noroviruses display resistance to inactivation by low pH, while the non-enteric species (e.g.; feline calicivirus are much more susceptible. The caliciviruses are inactivated by a variety of chemicals, including alcohols, oxidizing agents, aldehydes, and β-propiolactone. As with inactivation of viruses in general, inactivation of caliciviruses by the various approaches may be matrix-, temperature-, and/or contact time-dependent. The susceptibilities of the caliciviruses to the various physical and chemical inactivation approaches are generally similar to those displayed by other small, non-enveloped viruses, with the exception that the parvoviruses and circoviruses may require higher temperatures for inactivation, while these families appear to be more susceptible to UV-C inactivation than are the caliciviruses.

  7. Mary Lyon's X-inactivation studies in the mouse laid the foundation ...

    Indian Academy of Sciences (India)

    2015-11-20

    Nov 20, 2015 ... bridge for women and graduated in 1946. She started gradu- ... working at the same time as Lyon, also observed that variega- tion in coat character ... X chromosome inactivation; single active X hypothesis. Journal of Genetics ...

  8. Chromosome Territories

    OpenAIRE

    Cremer, Thomas; Cremer, Marion

    2010-01-01

    Chromosome territories (CTs) constitute a major feature of nuclear architecture. In a brief statement, the possible contribution of nuclear architecture studies to the field of epigenomics is considered, followed by a historical account of the CT concept and the final compelling experimental evidence of a territorial organization of chromosomes in all eukaryotes studied to date. Present knowledge of nonrandom CT arrangements, of the internal CT architecture, and of structural interactions wit...

  9. Inactivation of Smad4 in gastric carcinomas.

    Science.gov (United States)

    Powell, S M; Harper, J C; Hamilton, S R; Robinson, C R; Cummings, O W

    1997-10-01

    Allelic loss of chromosome 18q has been noted in intestinal type gastric adenocarcinomas. Smad4 is a gene located at 18q that was recently cloned in humans and found to be significantly altered in pancreatic cancers. We sought to determine whether Smad4 genetic alterations played a significant role in gastric tumorigenesis by studying 35 gastric adenocarcinomas of all histopathological types and pathological stages. Microdissected specimens were used for mutational analysis of Smad4 at the nucleotide level, including the entire coding region and intron/exon boundaries. Allelic imbalance was also analyzed at the Smad4 locus using two nearby microsatellite markers. One case of apparent biallelic inactivation of Smad4 was found in our study of 35 gastric carcinomas. A nonsense point mutation at codon 334 was demonstrated, which, similar to other Smad4 mutations, is predicted to truncate the conserved COOH-terminal domain of this protein. This Smad4 C to T transition mutation was proven to be somatically acquired. Allelic loss was also noted on chromosome 18q at a marker near Smad4 in this mutated gastric cancer, apparently producing complete inactivation of Smad4 in this tumor. Significant 18q allelic loss (56% of 34 informative cases) was noted in our gastric carcinomas using microsatellite markers near the Smad4 locus, regardless of histological subtype or pathological stage. Additionally, three cases of microsatellite instability were observed. Thus, Smad4 inactivation was noted in our gastric carcinomas; however, this event was rare. The frequent loss of chromosomal arm 18q observed in gastric cancers suggests the presence of other tumor suppressor genes in this region that are involved in gastric tumorigenesis. Further studies are needed to identify these other targets of inactivation during gastric cancer development.

  10. Chromosomal aberration

    International Nuclear Information System (INIS)

    Ishii, Yutaka

    1988-01-01

    Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G 2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G 2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G 2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G 1 phase. (author)

  11. Implications for x-chromosome regulation from studies of human x-chromosome DNA

    International Nuclear Information System (INIS)

    Wolf, S.F.; Migeon, B.R.

    1983-01-01

    It is clear that there must be multiple events involved in the regulation of the mammalian X chromosome. The initial event, occurring about the time of implantation results in inactivation of all but a single X chromosome in diploid cells. A popular working hypothesis is that DNA modification, such as methylation or sequence rearrangement, might be responsible for maintenance of the inactive state. Methylation is particularly attractive, since the preference for methylating half-methylated sites might result in perpetuation of the differentiated state. In this paper we discuss several facets of our studies of X inactivation; specifically, our general strategy, studies of X DNA methylation, and studies of loci that escape inactivation. 47 references, 8 figures, 2 tables

  12. Centromere Destiny in Dicentric Chromosomes: New Insights from the Evolution of Human Chromosome 2 Ancestral Centromeric Region.

    Science.gov (United States)

    Chiatante, Giorgia; Giannuzzi, Giuliana; Calabrese, Francesco Maria; Eichler, Evan E; Ventura, Mario

    2017-07-01

    Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells. We investigate the most recent product of a chromosome fusion event fixed in the human lineage, human chromosome 2, whose stability was acquired by the suppression of one centromere, resulting in a unique difference in chromosome number between humans (46 chromosomes) and our most closely related ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and comparative sequence data, we deeply characterize the relicts of the chromosome 2q ancestral centromere and its flanking regions, gaining insight into the ancestral organization that can be easily broadened to all acrocentric chromosome centromeres. Moreover, our analyses offered the opportunity to trace the evolutionary history of rDNA and satellite III sequences among great apes, thus suggesting a new hypothesis for the preferential inactivation of some human centromeres, including IIq. Our results suggest two possible centromere inactivation models to explain the evolutionarily stabilization of human chromosome 2 over the last 5-6 million years. Our results strongly favor centromere excision through a one-step process. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Statistics for X-chromosome associations.

    Science.gov (United States)

    Özbek, Umut; Lin, Hui-Min; Lin, Yan; Weeks, Daniel E; Chen, Wei; Shaffer, John R; Purcell, Shaun M; Feingold, Eleanor

    2018-06-13

    In a genome-wide association study (GWAS), association between genotype and phenotype at autosomal loci is generally tested by regression models. However, X-chromosome data are often excluded from published analyses of autosomes because of the difference between males and females in number of X chromosomes. Failure to analyze X-chromosome data at all is obviously less than ideal, and can lead to missed discoveries. Even when X-chromosome data are included, they are often analyzed with suboptimal statistics. Several mathematically sensible statistics for X-chromosome association have been proposed. The optimality of these statistics, however, is based on very specific simple genetic models. In addition, while previous simulation studies of these statistics have been informative, they have focused on single-marker tests and have not considered the types of error that occur even under the null hypothesis when the entire X chromosome is scanned. In this study, we comprehensively tested several X-chromosome association statistics using simulation studies that include the entire chromosome. We also considered a wide range of trait models for sex differences and phenotypic effects of X inactivation. We found that models that do not incorporate a sex effect can have large type I error in some cases. We also found that many of the best statistics perform well even when there are modest deviations, such as trait variance differences between the sexes or small sex differences in allele frequencies, from assumptions. © 2018 WILEY PERIODICALS, INC.

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

    Science.gov (United States)

    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

  15. Demasculinization of the Anopheles gambiae X chromosome

    Directory of Open Access Journals (Sweden)

    Magnusson Kalle

    2012-05-01

    Full Text Available Abstract Background In a number of organisms sex-biased genes are non-randomly distributed between autosomes and the shared sex chromosome X (or Z. Studies on Anopheles gambiae have produced conflicting results regarding the underrepresentation of male-biased genes on the X chromosome and it is unclear to what extent sexual antagonism, dosage compensation or X-inactivation in the male germline, the evolutionary forces that have been suggested to affect the chromosomal distribution of sex-biased genes, are operational in Anopheles. Results We performed a meta-analysis of sex-biased gene expression in Anopheles gambiae which provides evidence for a general underrepresentation of male-biased genes on the X-chromosome that increased in significance with the observed degree of sex-bias. A phylogenomic comparison between Drosophila melanogaster, Aedes aegypti and Culex quinquefasciatus also indicates that the Anopheles X chromosome strongly disfavours the evolutionary conservation of male-biased expression and that novel male-biased genes are more likely to arise on autosomes. Finally, we demonstrate experimentally that transgenes situated on the Anopheles gambiae X chromosome are transcriptionally silenced in the male germline. Conclusion The data presented here support the hypothesis that the observed demasculinization of the Anopheles X chromosome is driven by X-chromosome inactivation in the male germline and by sexual antagonism. The demasculinization appears to be the consequence of a loss of male-biased expression, rather than a failure in the establishment or the extinction of male-biased genes.

  16. Selfish X chromosomes and speciation.

    Science.gov (United States)

    Patten, Manus M

    2017-12-27

    In two papers published at about the same time almost thirty years ago, Frank (Evolution, 45, 1991a, 262) and Hurst and Pomiankowski (Genetics, 128, 1991, 841) independently suggested that divergence of meiotic drive systems-comprising genes that cheat meiosis and genes that suppress this cheating-might provide a general explanation for Haldane's rule and the large X-effect in interspecific hybrids. Although at the time, the idea was met with skepticism and a conspicuous absence of empirical support, the tide has since turned. Some of the clearest mechanistic explanations we have for hybrid male sterility involve meiotic drive systems, and several other cases of hybrid sterility are suggestive of a role for meiotic drive. In this article, I review these ideas and their descendants and catalog the current evidence for the meiotic drive model of speciation. In addition, I suggest that meiotic drive is not the only intragenomic conflict to involve the X chromosome and contribute to hybrid incompatibility. Sexually and parentally antagonistic selection pressures can also pit the X chromosome and autosomes against each other. The resulting intragenomic conflicts should lead to co-evolution within populations and divergence between them, thus increasing the likelihood of incompatibilities in hybrids. I provide a sketch of these ideas and interpret some empirical patterns in the light of these additional X-autosome conflicts. © 2017 John Wiley & Sons Ltd.

  17. Ultraviolet inactivation of papain

    International Nuclear Information System (INIS)

    Baugher, J.F.; Grossweiner, L.I.

    1975-01-01

    Flash photolysis transient spectra (lambda > 250 nm) of aqueous papain showed that the initial products are the neutral tryptophan radical Trp (lambdasub(max) 510 nm), the tryptophan triplet state 3 Trp (lambdasub(max) 460 nm), the disulfide bridge electron adduct -SS - - (lambdasub(max) 420 nm) and the hydrated electron esub(aq) - . The -SS - - yield was not altered by nitrous oxide or air, indicating that the formation of this product does not involve electrons in the external medium. The original papain preparation was activated by irradiating under nitrogen. The action spectrum supports previous work attributing the low initial activity to blocking of cysteinyl site 25 with a mixed disulfide. Flask lamp irradiation in nitrogen led to activation at low starting activities and inactivation at higher starting activities, while only inactivation at the same quantum yield was observed with air saturation. The results are consistent with photoionization of an essential tryptophyl residue as the key inactivating step. (author)

  18. Some factors affecting urokinase inactivation. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Hiroo; Iketa, Yoshito

    1985-10-01

    The enzymatic activity of urokinase adsorbed on various polymer surfaces was measured to study the interaction between protein and polymers. The polymer films on which urokinase was adsorbed were exposed to either a high temperature or ..gamma..-radiation. The thermal inactivation rates were higher on hydrophobic polymers such as poly(ethylene terephthalate), nylon 6, and poly(vinylidene fluoride) than hydrophilic polymers like cellulose and ethylene-vinyl alcohol copolymer, indicating their substantial dependence on the interfacial free energy between the polymer and water. A similar dependence was also seen for the ..gamma..-radiation inactivation. Urokinase adsorbed on the hydrophobic polymers lost more easily its enzymatic activity by exposure to ..gamma..-radiation. The interfacial free energy seems to be one of the driving forces to denaturate proteins on polymers.

  19. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

    Wang, Zongji; Zhang, Jilin; Yang, Wei

    2014-01-01

    BACKGROUND: Sex chromosomes exhibit many unusual patterns in sequence and gene expression relative to autosomes. Birds have evolved a female heterogametic sex system (male ZZ, female ZW), through stepwise suppression of recombination between chrZ and chrW. To address the broad patterns and complex...... driving forces of Z chromosome evolution, we analyze here 45 newly available bird genomes and four species' transcriptomes, over their course of recombination loss between the sex chromosomes. RESULTS: We show Z chromosomes in general have a significantly higher substitution rate in introns and synonymous...... ('fast-Z' evolution). And species with a lower level of intronic heterozygosities tend to evolve even faster on the Z chromosome. Further analysis of fast-evolving genes' enriched functional categories and sex-biased expression patterns support that, fast-Z evolution in birds is mainly driven by genetic...

  20. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  1. Three new loci for determining x chromosome inactivation patterns

    DEFF Research Database (Denmark)

    Bertelsen, Birgitte; Tümer, Zeynep; Ravn, Kirstine

    2011-01-01

    . The reliability of the loci was validated by showing a high correlation between the results obtained by employing the new loci and the AR locus using DNA from 15 females who were informative for all four loci. Altogether, we show that these loci can be applied easily in molecular diagnostic laboratories, either...

  2. The chicken Z chromosome is enriched for genes with preferential expression in ovarian somatic cells

    Czech Academy of Sciences Publication Activity Database

    Mořkovský, L.; Storchová, R.; Plachý, Jiří; Ivánek, Robert; Divina, Petr; Hejnar, Jiří

    2010-01-01

    Roč. 70, č. 2 (2010), s. 129-136 ISSN 0022-2844 Institutional research plan: CEZ:AV0Z50520514 Keywords : Z chromosome * meiotic sex chromosome inactivation * sex ual antagonisms Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.311, year: 2010

  3. Absence of methylation of a CpG-rich region at the 5' end of the MIC2 gene on the active X, the inactive X, and the Y chromosome

    International Nuclear Information System (INIS)

    Goodfellow, P.J.; Mondello, C.; Darling, S.M.; Pym, B.; Little, P.; Goodfellow, P.N.

    1988-01-01

    The authors have identified and characterized a Hpa II tiny fragment (HTF) island associated with the promoter region of the pseudoautosomal gene MIC2. The MIC2 HTF island is unmethylated on both the active and inactive X chromosome and is similarly unmethylated on the Y chromosome. Unlike the majority of genes borne on the X chromosome, MIC2 fails to undergo X chromosome inactivation. HTF islands associated with X chromosome-liked genes that are inactivated are highly methylated on the inactive or transcriptionally silent homologue. The failure of MIC2 to undergo X chromosome inactivation correlates with the lack of methylation of HTF island at the 5' end of the gene. These results provide further evidence that DNA methylation plays an important role in the phenomenon of X chromosome inactivation

  4. Deciphering the Code of the Cancer Genome: Mechanisms of Chromosome Rearrangement

    OpenAIRE

    Willis, Nicholas A.; Rass, Emilie; Scully, Ralph

    2015-01-01

    Chromosome rearrangement plays a causal role in tumorigenesis by contributing to the inactivation of tumor suppressor genes, the dysregulated expression or amplification of oncogenes and the generation of novel gene fusions. Chromosome breaks are important intermediates in this process. How, when and where these breaks arise and the specific mechanisms engaged in their repair strongly influence the resulting patterns of chromosome rearrangement. Here, we review recent progress in understandin...

  5. Dementia & Driving

    Science.gov (United States)

    ... have to give up driving. Many people associate driving with self-reliance and freedom; the loss of driving privileges ... familiar roads and avoid long distances. Avoid heavy traffic and heavily traveled roads. Avoid driving at night and in bad weather. Reduce the ...

  6. Mitotic chromosome structure

    International Nuclear Information System (INIS)

    Heermann, Dieter W.

    2012-01-01

    Mounting evidence is compiling linking the physical organizational structure of chromosomes and the nuclear structure to biological function. At the base of the physical organizational structure of both is the concept of loop formation. This implies that physical proximity within chromosomes is provided for otherwise distal genomic regions and thus hierarchically organizing the chromosomes. Together with entropy many experimental observations can be explained with these two concepts. Among the observations that can be explained are the measured physical extent of the chromosomes, their shape, mechanical behavior, the segregation into territories (chromosomal and territories within chromosomes), the results from chromosome conformation capture experiments, as well as linking gene expression to structural organization.

  7. Mitotic chromosome structure

    Energy Technology Data Exchange (ETDEWEB)

    Heermann, Dieter W., E-mail: heermann@tphys.uni-heidelberg.de

    2012-07-15

    Mounting evidence is compiling linking the physical organizational structure of chromosomes and the nuclear structure to biological function. At the base of the physical organizational structure of both is the concept of loop formation. This implies that physical proximity within chromosomes is provided for otherwise distal genomic regions and thus hierarchically organizing the chromosomes. Together with entropy many experimental observations can be explained with these two concepts. Among the observations that can be explained are the measured physical extent of the chromosomes, their shape, mechanical behavior, the segregation into territories (chromosomal and territories within chromosomes), the results from chromosome conformation capture experiments, as well as linking gene expression to structural organization.

  8. Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes.

    Directory of Open Access Journals (Sweden)

    Kaitlin M Stimpson

    2010-08-01

    Full Text Available Genome rearrangement often produces chromosomes with two centromeres (dicentrics that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extra-chromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.

  9. Why Do Sex Chromosomes Stop Recombining?

    Science.gov (United States)

    Ponnikas, Suvi; Sigeman, Hanna; Abbott, Jessica K; Hansson, Bengt

    2018-04-28

    It is commonly assumed that sex chromosomes evolve recombination suppression because selection favours linkage between sex-determining and sexually antagonistic genes. However, although the role of sexual antagonism during sex chromosome evolution has attained strong support from theory, experimental and observational evidence is rare or equivocal. Here, we highlight alternative, often neglected, hypotheses for recombination suppression on sex chromosomes, which invoke meiotic drive, heterozygote advantage, and genetic drift, respectively. We contrast the hypotheses, the situations when they are likely to be of importance, and outline why it is surprisingly difficult to test them. Lastly, we discuss future research directions (including modelling, population genomics, comparative approaches, and experiments) to disentangle the different hypotheses of sex chromosome evolution. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Sex chromosomes and speciation in Drosophila

    Science.gov (United States)

    Presgraves, Daven C.

    2010-01-01

    Two empirical rules suggest that sex chromosomes play a special role in speciation. The first is Haldane's rule— the preferential sterility and inviability of species hybrids of the heterogametic (XY) sex. The second is the disproportionately large effect of the X chromosome in genetic analyses of hybrid sterility. Whereas the causes of Haldane's rule are well established, the causes of the ‘large X-effect’ have remained controversial. New genetic analyses in Drosophila confirm that the X is a hotspot for hybrid male sterility factors, providing a proximate explanation for the large X-effect. Several other new findings— on faster X evolution, X chromosome meiotic drive, and the regulation of the X chromosome in the male-germline— provide plausible evolutionary explanations for the large X-effect. PMID:18514967

  11. Distracted driving

    Science.gov (United States)

    ... including maps) The Dangers of Talking on the Phone While Driving You are four times more likely to get ... of reach. If you are caught using a phone while driving, you may risk a ticket or fine. Most ...

  12. Distracted Driving

    Science.gov (United States)

    ... and increased awareness of distracted driving using radio advertisements, news stories, and similar media. After the projects ... available at www.trafficsafetymarketing.gov . Distracted Driving Enforcement – TV Ads (Paid). For re-tagging, go to: www. ...

  13. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  14. Genotype and phenotype in Klinefelter syndrome - impact of androgen receptor polymorphism and skewed X inactivation

    DEFF Research Database (Denmark)

    Bojesen, A; Hertz, J M; Gravholt, C H

    2011-01-01

    The phenotypic variation of Klinefelter syndrome (KS) is wide and may by caused by various genetic and epigenetic effects. Skewed inactivation of the supra-numerical X chromosome and polymorphism in the androgen receptor (AR) have been suggested as plausible causes. We wanted to describe X...

  15. Fetal chromosome analysis: screening for chromosome disease?

    DEFF Research Database (Denmark)

    Philip, J; Tabor, Ann; Bang, J

    1983-01-01

    The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocentesis performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group...... A + B). Pregnant women 35 years of age, women who previously had a chromosomally abnormal child, families with translocation carriers or other heritable chromosomal disease, families where the father was 50 years or more and women in families with a history of Down's syndrome (group A), were compared...... to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25-34 years of age, in whom all heritable diseases were excluded (group C). The risk of unbalanced...

  16. Chromosome painting in plants.

    NARCIS (Netherlands)

    Schubert, I.; Fransz, P.F.; Fuchs, J.; Jong, de J.H.

    2001-01-01

    The current 'state-of-art' as to chromosome painting in plants is reviewed. We define different situations described as painting so far: i) Genomic in situ hybridisation (GISH) with total genomic DNA to distinguish alien chromosomes on the basis of divergent dispersed repeats, ii) 'Chromosomal in

  17. Pathogen inactivation techniques.

    Science.gov (United States)

    Pelletier, J P R; Transue, S; Snyder, E L

    2006-01-01

    The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area

  18. Free radical inactivation of trypsin

    International Nuclear Information System (INIS)

    Cudina, Ivana; Jovanovic, S.V.

    1988-01-01

    Reactivities of free radical oxidants, radical OH, Br2-anion radical and Cl 3 COO radical and a reductant, CO2-anion radical, with trypsin and reactive protein components were determined by pulse radiolysis of aqueous solutions at pH 7, 20 0 C. Highly reactive free radicals, radical OH, Br2-anion radical and CO2-anion radical, react with trypsin at diffusion controlled rates. Moderately reactive trichloroperoxy radical, k(Cl 3 COO radical + trypsin) preferentially oxidizes histidine residues. The efficiency of inactivation of trypsin by free radicals is inversely proportional to their reactivity. The yields of inactivation of trypsin by radical OH, Br2-anion radical and CO2-anion radical are low, G(inactivation) = 0.6-0.8, which corresponds to ∼ 10% of the initially produced radicals. In contrast, Cl 3 COO radical inactivates trypsin with ∼ 50% efficiency, i.e. G(inactivation) = 3.2. (author)

  19. The DNA sequence of the human X chromosome

    Science.gov (United States)

    Ross, Mark T.; Grafham, Darren V.; Coffey, Alison J.; Scherer, Steven; McLay, Kirsten; Muzny, Donna; Platzer, Matthias; Howell, Gareth R.; Burrows, Christine; Bird, Christine P.; Frankish, Adam; Lovell, Frances L.; Howe, Kevin L.; Ashurst, Jennifer L.; Fulton, Robert S.; Sudbrak, Ralf; Wen, Gaiping; Jones, Matthew C.; Hurles, Matthew E.; Andrews, T. Daniel; Scott, Carol E.; Searle, Stephen; Ramser, Juliane; Whittaker, Adam; Deadman, Rebecca; Carter, Nigel P.; Hunt, Sarah E.; Chen, Rui; Cree, Andrew; Gunaratne, Preethi; Havlak, Paul; Hodgson, Anne; Metzker, Michael L.; Richards, Stephen; Scott, Graham; Steffen, David; Sodergren, Erica; Wheeler, David A.; Worley, Kim C.; Ainscough, Rachael; Ambrose, Kerrie D.; Ansari-Lari, M. Ali; Aradhya, Swaroop; Ashwell, Robert I. S.; Babbage, Anne K.; Bagguley, Claire L.; Ballabio, Andrea; Banerjee, Ruby; Barker, Gary E.; Barlow, Karen F.; Barrett, Ian P.; Bates, Karen N.; Beare, David M.; Beasley, Helen; Beasley, Oliver; Beck, Alfred; Bethel, Graeme; Blechschmidt, Karin; Brady, Nicola; Bray-Allen, Sarah; Bridgeman, Anne M.; Brown, Andrew J.; Brown, Mary J.; Bonnin, David; Bruford, Elspeth A.; Buhay, Christian; Burch, Paula; Burford, Deborah; Burgess, Joanne; Burrill, Wayne; Burton, John; Bye, Jackie M.; Carder, Carol; Carrel, Laura; Chako, Joseph; Chapman, Joanne C.; Chavez, Dean; Chen, Ellson; Chen, Guan; Chen, Yuan; Chen, Zhijian; Chinault, Craig; Ciccodicola, Alfredo; Clark, Sue Y.; Clarke, Graham; Clee, Chris M.; Clegg, Sheila; Clerc-Blankenburg, Kerstin; Clifford, Karen; Cobley, Vicky; Cole, Charlotte G.; Conquer, Jen S.; Corby, Nicole; Connor, Richard E.; David, Robert; Davies, Joy; Davis, Clay; Davis, John; Delgado, Oliver; DeShazo, Denise; Dhami, Pawandeep; Ding, Yan; Dinh, Huyen; Dodsworth, Steve; Draper, Heather; Dugan-Rocha, Shannon; Dunham, Andrew; Dunn, Matthew; Durbin, K. James; Dutta, Ireena; Eades, Tamsin; Ellwood, Matthew; Emery-Cohen, Alexandra; Errington, Helen; Evans, Kathryn L.; Faulkner, Louisa; Francis, Fiona; Frankland, John; Fraser, Audrey E.; Galgoczy, Petra; Gilbert, James; Gill, Rachel; Glöckner, Gernot; Gregory, Simon G.; Gribble, Susan; Griffiths, Coline; Grocock, Russell; Gu, Yanghong; Gwilliam, Rhian; Hamilton, Cerissa; Hart, Elizabeth A.; Hawes, Alicia; Heath, Paul D.; Heitmann, Katja; Hennig, Steffen; Hernandez, Judith; Hinzmann, Bernd; Ho, Sarah; Hoffs, Michael; Howden, Phillip J.; Huckle, Elizabeth J.; Hume, Jennifer; Hunt, Paul J.; Hunt, Adrienne R.; Isherwood, Judith; Jacob, Leni; Johnson, David; Jones, Sally; de Jong, Pieter J.; Joseph, Shirin S.; Keenan, Stephen; Kelly, Susan; Kershaw, Joanne K.; Khan, Ziad; Kioschis, Petra; Klages, Sven; Knights, Andrew J.; Kosiura, Anna; Kovar-Smith, Christie; Laird, Gavin K.; Langford, Cordelia; Lawlor, Stephanie; Leversha, Margaret; Lewis, Lora; Liu, Wen; Lloyd, Christine; Lloyd, David M.; Loulseged, Hermela; Loveland, Jane E.; Lovell, Jamieson D.; Lozado, Ryan; Lu, Jing; Lyne, Rachael; Ma, Jie; Maheshwari, Manjula; Matthews, Lucy H.; McDowall, Jennifer; McLaren, Stuart; McMurray, Amanda; Meidl, Patrick; Meitinger, Thomas; Milne, Sarah; Miner, George; Mistry, Shailesh L.; Morgan, Margaret; Morris, Sidney; Müller, Ines; Mullikin, James C.; Nguyen, Ngoc; Nordsiek, Gabriele; Nyakatura, Gerald; O’Dell, Christopher N.; Okwuonu, Geoffery; Palmer, Sophie; Pandian, Richard; Parker, David; Parrish, Julia; Pasternak, Shiran; Patel, Dina; Pearce, Alex V.; Pearson, Danita M.; Pelan, Sarah E.; Perez, Lesette; Porter, Keith M.; Ramsey, Yvonne; Reichwald, Kathrin; Rhodes, Susan; Ridler, Kerry A.; Schlessinger, David; Schueler, Mary G.; Sehra, Harminder K.; Shaw-Smith, Charles; Shen, Hua; Sheridan, Elizabeth M.; Shownkeen, Ratna; Skuce, Carl D.; Smith, Michelle L.; Sotheran, Elizabeth C.; Steingruber, Helen E.; Steward, Charles A.; Storey, Roy; Swann, R. Mark; Swarbreck, David; Tabor, Paul E.; Taudien, Stefan; Taylor, Tineace; Teague, Brian; Thomas, Karen; Thorpe, Andrea; Timms, Kirsten; Tracey, Alan; Trevanion, Steve; Tromans, Anthony C.; d’Urso, Michele; Verduzco, Daniel; Villasana, Donna; Waldron, Lenee; Wall, Melanie; Wang, Qiaoyan; Warren, James; Warry, Georgina L.; Wei, Xuehong; West, Anthony; Whitehead, Siobhan L.; Whiteley, Mathew N.; Wilkinson, Jane E.; Willey, David L.; Williams, Gabrielle; Williams, Leanne; Williamson, Angela; Williamson, Helen; Wilming, Laurens; Woodmansey, Rebecca L.; Wray, Paul W.; Yen, Jennifer; Zhang, Jingkun; Zhou, Jianling; Zoghbi, Huda; Zorilla, Sara; Buck, David; Reinhardt, Richard; Poustka, Annemarie; Rosenthal, André; Lehrach, Hans; Meindl, Alfons; Minx, Patrick J.; Hillier, LaDeana W.; Willard, Huntington F.; Wilson, Richard K.; Waterston, Robert H.; Rice, Catherine M.; Vaudin, Mark; Coulson, Alan; Nelson, David L.; Weinstock, George; Sulston, John E.; Durbin, Richard; Hubbard, Tim; Gibbs, Richard A.; Beck, Stephan; Rogers, Jane; Bentley, David R.

    2009-01-01

    The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence. PMID:15772651

  20. Inactivation of Microorganisms

    Science.gov (United States)

    Alzamora, Stella Maris; Guerrero, Sandra N.; Schenk, Marcela; Raffellini, Silvia; López-Malo, Aurelio

    Minimal processing techniques for food preservation allow better retention of product flavor, texture, color, and nutrient content than comparable conventional treatments. A wide range of novel alternative physical factors have been intensely investigated in the last two decades. These physical factors can cause inactivation of microorganisms at ambient or sublethal temperatures (e.g., high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed light, and ultraviolet light). These technologies have been reported to reduce microorganism population in foods while avoiding the deleterious effects of severe heating on quality. Among technologies, high-energy ultrasound (i.e., intensities higher than 1 W/cm2, frequencies between 18 and 100 kHz) has attracted considerable interest for food preservation applications (Mason et al., 1996; Povey and Mason, 1998).

  1. Mean inactivation dose (D)

    International Nuclear Information System (INIS)

    Vijayakumar, S.; Ng, T.C.; Raudkivi, U.; Meaney, T.J.

    1990-01-01

    By predicting treatment outcome to radiotherapy from in vitro radiobiological parameters, not only individual patient treatments can be tailored, but also new promising treatment protocols can be tried in patients in whom unfavorable outcome is predicted. In this respect, choosing the right parameter can be very important. Unlike D 0 and N which provide information of the distal part of the survival curve, mean inactivation dose (D) estimates overall radiosensitivity. However, the parameters reflecting the response at the clinically relevant low-dose region are neglected in the literature. In a literature survey of 98 papers in which survival curves or D 0 /N were used, only in 2 D was used. In 21 papers the D 0 /n values were important in drawing conclusions. By calculating D in 3 of these 21 papers, we show that the conclusion drawn may be altered with the use of D. The importance of ''low-dose-region-parameters'' is reviewed. (orig.)

  2. Pile Driving

    Science.gov (United States)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  3. Controlled initiation of chromosomal replication in Escherichia coli requires functional Hda protein.

    Science.gov (United States)

    Camara, Johanna Eltz; Skarstad, Kirsten; Crooke, Elliott

    2003-05-01

    Regulatory inactivation of DnaA helps ensure that the Escherichia coli chromosome is replicated only once per cell cycle, through accelerated hydrolysis of active replication initiator ATP-DnaA to inactive ADP-DnaA. Analysis of deltahda strains revealed that the regulatory inactivation of DnaA component Hda is necessary for maintaining controlled initiation but not for cell growth or viability.

  4. X inactivation in females with X-linked Charcot-Marie-Tooth disease.

    LENUS (Irish Health Repository)

    Murphy, Sinéad M

    2012-07-01

    X-linked Charcot-Marie-Tooth disease (CMT1X) is the second most common inherited neuropathy, caused by mutations in gap junction beta-1 (GJB1). Males have a uniformly moderately severe phenotype while females have a variable phenotype, suggested to be due to X inactivation. We aimed to assess X inactivation pattern in females with CMT1X and correlate this with phenotype using the CMT examination score to determine whether the X inactivation pattern accounted for the variable phenotype in females with CMT1X. We determined X inactivation pattern in 67 females with CMT1X and 24 controls using the androgen receptor assay. We were able to determine which X chromosome carried the GJB1 mutation in 30 females. There was no difference in X inactivation pattern between patients and controls. In addition, there was no correlation between X inactivation pattern in blood and phenotype. A possible explanation for these findings is that the X inactivation pattern in Schwann cells rather than in blood may explain the variable phenotype in females with CMT1X.

  5. Chromosomal Evolution in Chiroptera.

    Science.gov (United States)

    Sotero-Caio, Cibele G; Baker, Robert J; Volleth, Marianne

    2017-10-13

    Chiroptera is the second largest order among mammals, with over 1300 species in 21 extant families. The group is extremely diverse in several aspects of its natural history, including dietary strategies, ecology, behavior and morphology. Bat genomes show ample chromosome diversity (from 2n = 14 to 62). As with other mammalian orders, Chiroptera is characterized by clades with low, moderate and extreme chromosomal change. In this article, we will discuss trends of karyotypic evolution within distinct bat lineages (especially Phyllostomidae, Hipposideridae and Rhinolophidae), focusing on two perspectives: evolution of genome architecture, modes of chromosomal evolution, and the use of chromosome data to resolve taxonomic problems.

  6. Chromosomal Evolution in Chiroptera

    Directory of Open Access Journals (Sweden)

    Cibele G. Sotero-Caio

    2017-10-01

    Full Text Available Chiroptera is the second largest order among mammals, with over 1300 species in 21 extant families. The group is extremely diverse in several aspects of its natural history, including dietary strategies, ecology, behavior and morphology. Bat genomes show ample chromosome diversity (from 2n = 14 to 62. As with other mammalian orders, Chiroptera is characterized by clades with low, moderate and extreme chromosomal change. In this article, we will discuss trends of karyotypic evolution within distinct bat lineages (especially Phyllostomidae, Hipposideridae and Rhinolophidae, focusing on two perspectives: evolution of genome architecture, modes of chromosomal evolution, and the use of chromosome data to resolve taxonomic problems.

  7. Impaired Driving

    Science.gov (United States)

    ... Get the Facts What Works: Strategies to Increase Car Seat and Booster Seat ... narcotics. 3 That’s one percent of the 111 million self-reported episodes of alcohol-impaired driving among U.S. ...

  8. Tumor suppressor genes that escape from X-inactivation contribute to cancer sex bias

    OpenAIRE

    Dunford, Andrew; Weinstock, David M.; Savova, Virginia; Schumacher, Steven E.; Cleary, John P.; Yoda, Akinori; Sullivan, Timothy J.; Hess, Julian M.; Gimelbrant, Alexander A.; Beroukhim, Rameen; Lawrence, Michael S.; Getz, Gad; Lane, Andrew A.

    2016-01-01

    There is a striking and unexplained male predominance across many cancer types. A subset of X chromosome (chrX) genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative “Escape from X-Inactivation Tumor Suppressor” (EXITS) genes, we compared somatic alterations from >4100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) chrX genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) ...

  9. Discrimination of chromosome by autoradiography

    International Nuclear Information System (INIS)

    Masubuchi, Masanori

    1975-01-01

    This paper describes discrimination of chromosome by autoradiography. In this method, the difference in DNA synthetic phase between each chromosome was used as a standard, and the used chromosome was in metaphase, as morphological characteristics were markedly in this phase. Cell cycle and autoradiography with 3 H-thymidine were also examined. In order to discriminate chromosome by autoradiography, it was effective to utilize the labelled pattern in late DNA synthetic phase, where asynchronous replication of chromosome appeared most obviously. DNA synthesis in chromosome was examined in each DNA synthetic phase by culturing the chromosome after the treatment with 3 H-thymidine and altering the time to prepare chromosome specimen. Discrimination of chromosome in plants and animals by autoradiography was also mentioned. It was noticed as a structural and functional discrimination of chromosome to observe amino acid uptake into chromosome protein and to utilize the difference in labelled pattern between the sites of chromosome. (K. Serizawa)

  10. Fetal chromosome analysis

    DEFF Research Database (Denmark)

    Philip, J; Tabor, A; Bang, J

    1983-01-01

    The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocentesis performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group...... A + B). Pregnant women 35 years of age, women who previously had a chromosomally abnormal child, families with translocation carriers or other heritable chromosomal disease, families where the father was 50 years or more and women in families with a history of Down's syndrome (group A), were compared...... to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25-34 years of age, in whom all heritable diseases were excluded (group C). The risk of unbalanced...

  11. Selfish supernumerary chromosome reveals its origin as a mosaic of host genome and organellar sequences.

    Science.gov (United States)

    Martis, Mihaela Maria; Klemme, Sonja; Banaei-Moghaddam, Ali Mohammad; Blattner, Frank R; Macas, Jiří; Schmutzer, Thomas; Scholz, Uwe; Gundlach, Heidrun; Wicker, Thomas; Šimková, Hana; Novák, Petr; Neumann, Pavel; Kubaláková, Marie; Bauer, Eva; Haseneyer, Grit; Fuchs, Jörg; Doležel, Jaroslav; Stein, Nils; Mayer, Klaus F X; Houben, Andreas

    2012-08-14

    Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic elements comparable to selfish DNA, like transposons. In contrast to transposons, they are autonomously inherited independent of the host genome and have their own mechanisms of mitotic or meiotic drive. Although B chromosomes were first described a century ago, little is known about their origin and molecular makeup. The widely accepted view is that they are derived from fragments of A chromosomes and/or generated in response to interspecific hybridization. Through next-generation sequencing of sorted A and B chromosomes, we show that B chromosomes of rye are rich in gene-derived sequences, allowing us to trace their origin to fragments of A chromosomes, with the largest parts corresponding to rye chromosomes 3R and 7R. Compared with A chromosomes, B chromosomes were also found to accumulate large amounts of specific repeats and insertions of organellar DNA. The origin of rye B chromosomes occurred an estimated ∼1.1-1.3 Mya, overlapping in time with the onset of the genus Secale (1.7 Mya). We propose a comprehensive model of B chromosome evolution, including its origin by recombination of several A chromosomes followed by capturing of additional A-derived and organellar sequences and amplification of B-specific repeats.

  12. Biallelic inactivation of REV7 is associated with Fanconi anemia.

    Science.gov (United States)

    Bluteau, Dominique; Masliah-Planchon, Julien; Clairmont, Connor; Rousseau, Alix; Ceccaldi, Raphael; Dubois d'Enghien, Catherine; Bluteau, Olivier; Cuccuini, Wendy; Gachet, Stéphanie; Peffault de Latour, Régis; Leblanc, Thierry; Socié, Gérard; Baruchel, André; Stoppa-Lyonnet, Dominique; D'Andrea, Alan D; Soulier, Jean

    2016-09-01

    Fanconi anemia (FA) is a recessive genetic disease characterized by congenital abnormalities, chromosome instability, progressive bone marrow failure (BMF), and a strong predisposition to cancer. Twenty FA genes have been identified, and the FANC proteins they encode cooperate in a common pathway that regulates DNA crosslink repair and replication fork stability. We identified a child with severe BMF who harbored biallelic inactivating mutations of the translesion DNA synthesis (TLS) gene REV7 (also known as MAD2L2), which encodes the mutant REV7 protein REV7-V85E. Patient-derived cells demonstrated an extended FA phenotype, which included increased chromosome breaks and G2/M accumulation upon exposure to DNA crosslinking agents, γH2AX and 53BP1 foci accumulation, and enhanced p53/p21 activation relative to cells derived from healthy patients. Expression of WT REV7 restored normal cellular and functional phenotypes in the patient's cells, and CRISPR/Cas9 inactivation of REV7 in a non-FA human cell line produced an FA phenotype. Finally, silencing Rev7 in primary hematopoietic cells impaired progenitor function, suggesting that the DNA repair defect underlies the development of BMF in FA. Taken together, our genetic and functional analyses identified REV7 as a previously undescribed FA gene, which we term FANCV.

  13. Driving things

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2015-01-01

    I explore how participants organise involvement with objects brought into the car, relative to the demands of driving and social activity. Objects in cars commonly include phones or other technologies, food, body care products, texts, clothing, bags and carry items, toys, and even animals...... 2004, Haddington et al. 2012). I focus here especially on how the practical and interactional work of locating, seeing, placing, handling, hearing, and relinquishing, is ordered and accomplished relative to the emerging and contingent demands of both driving and social participation......, such that involvement with objects is constituted as secondary to driving in a multiactivity setting (e.g. Haddington et al. 2014). We see how events with, for, of, and even by objects can occur as predictable, planned and even designed for (e.g. changing glasses, applying body lotion), or might be unexpected...

  14. Chromosome painting reveals asynaptic full alignment of homologs and HIM-8-dependent remodeling of X chromosome territories during Caenorhabditis elegans meiosis.

    Science.gov (United States)

    Nabeshima, Kentaro; Mlynarczyk-Evans, Susanna; Villeneuve, Anne M

    2011-08-01

    During early meiotic prophase, a nucleus-wide reorganization leads to sorting of chromosomes into homologous pairs and to establishing associations between homologous chromosomes along their entire lengths. Here, we investigate global features of chromosome organization during this process, using a chromosome painting method in whole-mount Caenorhabditis elegans gonads that enables visualization of whole chromosomes along their entire lengths in the context of preserved 3D nuclear architecture. First, we show that neither spatial proximity of premeiotic chromosome territories nor chromosome-specific timing is a major factor driving homolog pairing. Second, we show that synaptonemal complex-independent associations can support full lengthwise juxtaposition of homologous chromosomes. Third, we reveal a prominent elongation of chromosome territories during meiotic prophase that initiates prior to homolog association and alignment. Mutant analysis indicates that chromosome movement mediated by association of chromosome pairing centers (PCs) with mobile patches of the nuclear envelope (NE)-spanning SUN-1/ZYG-12 protein complexes is not the primary driver of territory elongation. Moreover, we identify new roles for the X chromosome PC (X-PC) and X-PC binding protein HIM-8 in promoting elongation of X chromosome territories, separable from their role(s) in mediating local stabilization of pairing and association of X chromosomes with mobile SUN-1/ZYG-12 patches. Further, we present evidence that HIM-8 functions both at and outside of PCs to mediate chromosome territory elongation. These and other data support a model in which synapsis-independent elongation of chromosome territories, driven by PC binding proteins, enables lengthwise juxtaposition of chromosomes, thereby facilitating assessment of their suitability as potential pairing partners.

  15. Chromosome Painting Reveals Asynaptic Full Alignment of Homologs and HIM-8–Dependent Remodeling of X Chromosome Territories during Caenorhabditis elegans Meiosis

    Science.gov (United States)

    Nabeshima, Kentaro; Mlynarczyk-Evans, Susanna; Villeneuve, Anne M.

    2011-01-01

    During early meiotic prophase, a nucleus-wide reorganization leads to sorting of chromosomes into homologous pairs and to establishing associations between homologous chromosomes along their entire lengths. Here, we investigate global features of chromosome organization during this process, using a chromosome painting method in whole-mount Caenorhabditis elegans gonads that enables visualization of whole chromosomes along their entire lengths in the context of preserved 3D nuclear architecture. First, we show that neither spatial proximity of premeiotic chromosome territories nor chromosome-specific timing is a major factor driving homolog pairing. Second, we show that synaptonemal complex-independent associations can support full lengthwise juxtaposition of homologous chromosomes. Third, we reveal a prominent elongation of chromosome territories during meiotic prophase that initiates prior to homolog association and alignment. Mutant analysis indicates that chromosome movement mediated by association of chromosome pairing centers (PCs) with mobile patches of the nuclear envelope (NE)–spanning SUN-1/ZYG-12 protein complexes is not the primary driver of territory elongation. Moreover, we identify new roles for the X chromosome PC (X-PC) and X-PC binding protein HIM-8 in promoting elongation of X chromosome territories, separable from their role(s) in mediating local stabilization of pairing and association of X chromosomes with mobile SUN-1/ZYG-12 patches. Further, we present evidence that HIM-8 functions both at and outside of PCs to mediate chromosome territory elongation. These and other data support a model in which synapsis-independent elongation of chromosome territories, driven by PC binding proteins, enables lengthwise juxtaposition of chromosomes, thereby facilitating assessment of their suitability as potential pairing partners. PMID:21876678

  16. Deciphering the Code of the Cancer Genome: Mechanisms of Chromosome Rearrangement

    Science.gov (United States)

    Willis, Nicholas A.; Rass, Emilie; Scully, Ralph

    2015-01-01

    Chromosome rearrangement plays a causal role in tumorigenesis by contributing to the inactivation of tumor suppressor genes, the dysregulated expression or amplification of oncogenes and the generation of novel gene fusions. Chromosome breaks are important intermediates in this process. How, when and where these breaks arise and the specific mechanisms engaged in their repair strongly influence the resulting patterns of chromosome rearrangement. Here, we review recent progress in understanding how certain distinctive features of the cancer genome, including clustered mutagenesis, tandem segmental duplications, complex breakpoints, chromothripsis, chromoplexy and chromoanasynthesis may arise. PMID:26726318

  17. CHROMOSOMES OF WOODY SPECIES

    Directory of Open Access Journals (Sweden)

    Julio R Daviña

    2000-01-01

    Full Text Available Chromosome numbers of nine subtropical woody species collected in Argentina and Paraguay are reported. The counts tor Coutarea hexandra (2n=52, Inga vera subsp. affinis 2n=26 (Fabaceae and Chorisia speciosa 2n=86 (Bombacaceae are reported for the first time. The chromosome number given for Inga semialata 2n=52 is a new cytotype different from the previously reported. Somatic chromosome numbers of the other taxa studied are: Sesbania punicea 2n=12, S. virgata 2n=12 and Pilocarpus pennatifolius 2n=44 from Argentina

  18. Chromosomal abnormalities and autism

    Directory of Open Access Journals (Sweden)

    Farida El-Baz

    2016-01-01

    Conclusion: Chromosomal abnormalities were not detected in the studied autistic children, and so the relation between the genetics and autism still needs further work up with different study methods and techniques.

  19. Chromosome condensation and segmentation

    International Nuclear Information System (INIS)

    Viegas-Pequignot, E.M.

    1981-01-01

    Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr

  20. Chromosomal Evolution in Chiroptera

    OpenAIRE

    Sotero-Caio, Cibele G.; Baker, Robert J.; Volleth, Marianne

    2017-01-01

    Chiroptera is the second largest order among mammals, with over 1300 species in 21 extant families. The group is extremely diverse in several aspects of its natural history, including dietary strategies, ecology, behavior and morphology. Bat genomes show ample chromosome diversity (from 2n = 14 to 62). As with other mammalian orders, Chiroptera is characterized by clades with low, moderate and extreme chromosomal change. In this article, we will discuss trends of karyotypic evolution within d...

  1. Community Drive

    DEFF Research Database (Denmark)

    Magnussen, Rikke

    2018-01-01

    Schools and educational institutions are challenged by not adequately educating students for independent knowledge collaboration and solving of complex societal challenges (Bundsgaard & Hansen, 2016; Slot et al., 2017). As an alternative strategy to formal learning has Community-driven research...... opportunity to break boundaries between research institutions and surrounding communities through the involvement of new types of actors, knowledge forms and institutions (OECD, 2011). This paper presents the project Community Drive a three year cross disciplinary community-driven game– and data-based project....... In the paper we present how the project Community Drive initiated in May 2018 is based on results from pilot projects conducted from 2014 – 2017. Overall these studies showed that it is a strong motivational factor for students to be given the task to change their living conditions through redesign...

  2. Micromechanics of human mitotic chromosomes

    International Nuclear Information System (INIS)

    Sun, Mingxuan; Kawamura, Ryo; Marko, John F

    2011-01-01

    Eukaryote cells dramatically reorganize their long chromosomal DNAs to facilitate their physical segregation during mitosis. The internal organization of folded mitotic chromosomes remains a basic mystery of cell biology; its understanding would likely shed light on how chromosomes are separated from one another as well as into chromosome structure between cell divisions. We report biophysical experiments on single mitotic chromosomes from human cells, where we combine micromanipulation, nano-Newton-scale force measurement and biochemical treatments to study chromosome connectivity and topology. Results are in accord with previous experiments on amphibian chromosomes and support the 'chromatin network' model of mitotic chromosome structure. Prospects for studies of chromosome-organizing proteins using siRNA expression knockdowns, as well as for differential studies of chromosomes with and without mutations associated with genetic diseases, are also discussed

  3. Electric drives

    Energy Technology Data Exchange (ETDEWEB)

    1986-10-01

    Several electric vehicles have been tested in long-term tests, i.e. an electric passenger car (maximum speed 115 km/h) and several busses for use in pedestrians' zones, spas, airports, natural reserves, and urban transportation (DUO busses). The ICE high-speed train is discussed in some detail, i.e. its aeroacoustic and aerodynamic design, running gear, computer-controlled drives and brakes, diagnostic systems, and electrical equipment. The Berlin Maglev system is mentioned as well as current inverters in rail vehicles. (HWJ).

  4. Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

    Science.gov (United States)

    Mosiołek, Magdalena; Pasierbek, Paweł; Malarz, Janusz; Moś, Maria; Joachimiak, Andrzej J

    2005-01-01

    Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC) treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw.) Steam roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.

  5. Vibrio chromosome-specific families

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Ussery, David

    2014-01-01

    We have compared chromosome-specific genes in a set of 18 finished Vibrio genomes, and, in addition, also calculated the pan- and core-genomes from a data set of more than 250 draft Vibrio genome sequences. These genomes come from 9 known species and 2 unknown species. Within the finished...... chromosomes, we find a core set of 1269 encoded protein families for chromosome 1, and a core of 252 encoded protein families for chromosome 2. Many of these core proteins are also found in the draft genomes (although which chromosome they are located on is unknown.) Of the chromosome specific core protein...... families, 1169 and 153 are uniquely found in chromosomes 1 and 2, respectively. Gene ontology (GO) terms for each of the protein families were determined, and the different sets for each chromosome were compared. A total of 363 different "Molecular Function" GO categories were found for chromosome 1...

  6. Loss of heterozygosity of chromosome 15 in human lung carcinomas

    International Nuclear Information System (INIS)

    Mitchell, C.E.; Palmisano, W.A.; Lechner, J.F.

    1994-01-01

    Loss of heterozygosity (LOH) in tumors may be associated with the inactivation of tumor suppressor genes. A tumor suppressor gene for lung cancer may reside on chromosome 15, because deletions in this chromosome are frequently observed. Recently, it was reported that a newly discovered gene, GTPase-activating protein-3 (GAP3) maps to chromosome 15. GAP3 is a member of a family of GAP-related genes. Although the precise function of GAP3 is not known, it is thought that GAP3 is involved in the regulation of ras-like GTPase activities. Ras proteins have a low intrinsic activity, and their inactivation is dependent on GAPS in vivo. Oncogenic mutants of ras proteins, for example, at codons 12, 13, or 61, are resistant to GAP-mediated GTPase stimulation and are constituitively locked in their active, GTP-bound states. The purpose of this investigation was to determine the frequency and extent of LOH of GAP3 in a group of patients with lung cancer

  7. Safe driving for teens

    Science.gov (United States)

    Driving and teenagers; Teens and safe driving; Automobile safety - teenage drivers ... months before taking friends as passengers. Teenage-related driving deaths occur more often in certain conditions. OTHER SAFETY TIPS FOR TEENS Reckless driving is still a ...

  8. Normal X-inactivation mosaicism in corneas of heterozygous FlnaDilp2/+ female mice--a model of human Filamin A (FLNA diseases

    Directory of Open Access Journals (Sweden)

    Douvaras Panagiotis

    2012-02-01

    Full Text Available Abstract Background Some abnormalities of mouse corneal epithelial maintenance can be identified by the atypical mosaic patterns they produce in X-chromosome inactivation mosaics and chimeras. Human FLNA/+ females, heterozygous for X-linked, filamin A gene (FLNA mutations, display a range of disorders and X-inactivation mosaicism is sometimes quantitatively unbalanced. FlnaDilp2/+ mice, heterozygous for an X-linked filamin A (Flna nonsense mutation have variable eye, skeletal and other abnormalities, but X-inactivation mosaicism has not been investigated. The aim of this study was to determine whether X-inactivation mosaicism in the corneal epithelia of FlnaDilp2/+ mice was affected in any way that might predict abnormal corneal epithelial maintenance. Results X-chromosome inactivation mosaicism was studied in the corneal epithelium and a control tissue (liver of FlnaDilp2/+ and wild-type (WT female X-inactivation mosaics, hemizygous for the X-linked, LacZ reporter H253 transgene, using β-galactosidase histochemical staining. The corneal epithelia of FlnaDilp2/+ and WT X-inactivation mosaics showed similar radial, striped patterns, implying epithelial cell movement was not disrupted in FlnaDilp2/+ corneas. Corrected stripe numbers declined with age overall (but not significantly for either genotype individually, consistent with previous reports suggesting an age-related reduction in stem cell function. Corrected stripe numbers were not reduced in FlnaDilp2/+ compared with WT X-inactivation mosaics and mosaicism was not significantly more unbalanced in the corneal epithelia or livers of FlnaDilp2/+ than wild-type Flna+/+ X-inactivation mosaics. Conclusions Mosaic analysis identified no major effect of the mouse FlnaDilp2 mutation on corneal epithelial maintenance or the balance of X-inactivation mosaicism in the corneal epithelium or liver.

  9. Electochemical detection of chromosome translocation

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Dimaki, Maria; Silahtaroglu, Asli

    2014-01-01

    Cytogenetics is a study of the cell structure with a main focus on chromosomes content and their structure. Chromosome abnormalities, such as translocations may cause various genetic disorders and heametological malignancies. Chromosome translocations are structural rearrangements of two...... chromosomes that results in formation of derivative chromosomes with a mixed DNA sequence. The method currently used for their detection is Fluorescent In Situ Hybridization, which requires a use of expensive, fluorescently labeled probes that target the derivative chromosomes. We present here a double...... hybridization approach developed for label-free detection of the chromosome translocations. For specific translocation detection it is necessary to determine that the two DNA sequences forming a derivative chromosome are connected, which is achieved by two subsequent hybridization steps. The electrochemical...

  10. Mutations and chromosomal aberrations

    International Nuclear Information System (INIS)

    Kihlman, B.A.

    1977-01-01

    The genetic changes of mutations and chromosomal aberrations are discussed. The consequences of both depend not only on the type of genetic change produced but also on the type of cell that is affected and on the development stage of the organism. (C.F.)

  11. Chromosomes, cancer and radiosensitivity

    International Nuclear Information System (INIS)

    Samouhos, E.

    1983-01-01

    Some specific chromosomal abnormalities are associated with certain cancers. The earliest description of such a specific association is the one of the Philadelphia chromosome and myelogenous leukemia (1960). Other congenital karyotype abnormalities are associated with specific cancers. Examples of these are Down's syndrome with leukemia and Klinefelter's syndrome with male breast cancer. Genetic diseases of increased chromosome breakage, or of defective chromosome repair, are associated with greatly increased cancer incidence. Three such diseases have been recognized: 1) Fanconi's anemia, associated with leukemias and lymphomas, 2) Bloom's syndrome, associated with acute leukemias and lymphosarcoma, and 3) ataxia telangiectasia, associated with Hodgkin's disease, leukemia, and lymphosarcomas. Ten percent of individuals with ataxia telangiectasia will develop one of these neoplasms. Individuals with certain of these syndromes display an unusually high radiosensitivity. Radiation therapy for cancers has been fatal in patients who received as low as 3000 rad. This remarkable radiosensitivity has been quantitated in cell cultures from such cases. Evidence suggests that the apparent sensitivity may reflect subnormal ability to repair radiation damage. The rapid proliferation of information in this field stems from the interdigitation of many disciplines and specialties, including cytogenetics, cell biology, molecular biology, epidemiology, radiobiology, and several others. This paper is intended for clinicians; it presents a structured analytic scheme for correlating and classifying this multidisciplinary information as it becomes available

  12. Know Your Chromosomes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Know Your Chromosomes The Strong Holds of Family Trees. Vani Brahmachari. Series Article Volume 1 Issue 3 March 1996 pp 30-38. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...

  14. Telomere dysfunction and chromosome instability

    Energy Technology Data Exchange (ETDEWEB)

    Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)

    2012-02-01

    The ends of chromosomes are composed of a short repeat sequence and associated proteins that together form a cap, called a telomere, that keeps the ends from appearing as double-strand breaks (DSBs) and prevents chromosome fusion. The loss of telomeric repeat sequences or deficiencies in telomeric proteins can result in chromosome fusion and lead to chromosome instability. The similarity between chromosome rearrangements resulting from telomere loss and those found in cancer cells implicates telomere loss as an important mechanism for the chromosome instability contributing to human cancer. Telomere loss in cancer cells can occur through gradual shortening due to insufficient telomerase, the protein that maintains telomeres. However, cancer cells often have a high rate of spontaneous telomere loss despite the expression of telomerase, which has been proposed to result from a combination of oncogene-mediated replication stress and a deficiency in DSB repair in telomeric regions. Chromosome fusion in mammalian cells primarily involves nonhomologous end joining (NHEJ), which is the major form of DSB repair. Chromosome fusion initiates chromosome instability involving breakage-fusion-bridge (B/F/B) cycles, in which dicentric chromosomes form bridges and break as the cell attempts to divide, repeating the process in subsequent cell cycles. Fusion between sister chromatids results in large inverted repeats on the end of the chromosome, which amplify further following additional B/F/B cycles. B/F/B cycles continue until the chromosome acquires a new telomere, most often by translocation of the end of another chromosome. The instability is not confined to a chromosome that loses its telomere, because the instability is transferred to the chromosome donating a translocation. Moreover, the amplified regions are unstable and form extrachromosomal DNA that can reintegrate at new locations. Knowledge concerning the factors promoting telomere loss and its consequences is

  15. First steps in eukaryogenesis: Physical phenomena in the origin and evolution of chromosome structure

    International Nuclear Information System (INIS)

    Chela Flores, J.

    1995-01-01

    Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of the cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular, we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna.) When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes. (author). Abstract only

  16. First steps in eukaryogenesis: Physical phenomena in the origin and evolution of chromosome structure

    International Nuclear Information System (INIS)

    Chela Flores, J.

    1995-08-01

    Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of the inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna). When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes. (author). 65 refs

  17. B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

    Science.gov (United States)

    Dhar, Manoj K.; Kour, Gurmeet; Kaul, Sanjana

    2017-01-01

    Abstract Plantago lagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes. PMID:28919970

  18. Inhibition of Retinoblastoma Protein Inactivation

    Science.gov (United States)

    2017-11-01

    CONTRACT NUMBER Inhibition of Retinoblastoma Protein Inactivation 5b. GRANT NUMBER W81XWH-14-1-0329 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Seth M...confirmed 108 compounds as giving a dose-response curve with at least 30% inhibition at 10 µM. The flowchart of hit progression is shown on the...Cancer Research Program under Award No. W81XWH-14-1-0329 to S.M.R. Opinions, interpretations, conclusions, and recommendations are those of the author

  19. Y Fuse? Sex Chromosome Fusions in Fishes and Reptiles

    Science.gov (United States)

    Vamosi, Jana C.; Peichel, Catherine L.; Valenzuela, Nicole; Kitano, Jun

    2015-01-01

    Chromosomal fusion plays a recurring role in the evolution of adaptations and reproductive isolation among species, yet little is known of the evolutionary drivers of chromosomal fusions. Because sex chromosomes (X and Y in male heterogametic systems, Z and W in female heterogametic systems) differ in their selective, mutational, and demographic environments, those differences provide a unique opportunity to dissect the evolutionary forces that drive chromosomal fusions. We estimate the rate at which fusions between sex chromosomes and autosomes become established across the phylogenies of both fishes and squamate reptiles. Both the incidence among extant species and the establishment rate of Y-autosome fusions is much higher than for X-autosome, Z-autosome, or W-autosome fusions. Using population genetic models, we show that this pattern cannot be reconciled with many standard explanations for the spread of fusions. In particular, direct selection acting on fusions or sexually antagonistic selection cannot, on their own, account for the predominance of Y-autosome fusions. The most plausible explanation for the observed data seems to be (a) that fusions are slightly deleterious, and (b) that the mutation rate is male-biased or the reproductive sex ratio is female-biased. We identify other combinations of evolutionary forces that might in principle account for the data although they appear less likely. Our results shed light on the processes that drive structural changes throughout the genome. PMID:25993542

  20. Meiotic transmission of Drosophila pseudoobscura chromosomal arrangements.

    Directory of Open Access Journals (Sweden)

    Richard P Meisel

    Full Text Available Drosophila pseudoobscura harbors a rich gene arrangement polymorphism on the third chromosome generated by a series of overlapping paracentric inversions. The arrangements suppress recombination in heterokaryotypic individuals, which allows for the selective maintenance of coadapted gene complexes. Previous mapping experiments used to determine the degree to which recombination is suppressed in gene arrangement heterozygotes produced non-recombinant progeny in non-Mendelian ratios. The deviations from Mendelian expectations could be the result of viability differences between wild and mutant chromosomes, meiotic drive because of achiasmate pairing of homologues in heterokaryotypic females during meiosis, or a combination of both mechanisms. The possibility that the frequencies of the chromosomal arrangements in natural populations are affected by mechanisms other than adaptive selection led us to consider these hypotheses. We performed reciprocal crosses involving both heterozygous males and females to determine if the frequency of the non-recombinant progeny deviates significantly from Mendelian expectations and if the frequencies deviate between reciprocal crosses. We failed to observe non-Mendelian ratios in multiple crosses, and the frequency of the non-recombinant classes differed in only one of five pairs of reciprocal crosses despite sufficient power to detect these differences in all crosses. Our results indicate that deviations from Mendelian expectations in recombination experiments involving the D. pseudoobscura inversion system are most likely due to fitness differences of gene arrangement karyotypes in different environments.

  1. The effects of chromosome rearrangements on the expression of heterochromatic genes in chromosome 2L of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Wakimoto, B.T.; Hearn, M.G.

    1990-01-01

    The light (lt) gene of Drosophila melanogaster is located at the base of the left arm of chromosome 2, within or very near centromeric heterochromatin (2Lh). Chromosome rearrangements that move the lt + gene from its normal proximal position and place the gene in distal euchromatin result in mosaic or variegated expression of the gene. The cytogenetic and genetic properties of 17 lt-variegated rearrangements induced by X radiation are described in this report. The authors show that five of the heterochromatic genes adjacent to lt are subject to inactivation by these rearrangements and that the euchromatic loci in proximal 2L are not detectably affected. The properties of the rearrangements suggest that proximity to heterochromatin is an important regulatory requirement for at least six 2Lh genes. They discuss how the properties of the position effects on heterochromatic genes relate to other proximity-dependent phenomena such as transvection

  2. Neocentric X-chromosome in a girl with Turner-like syndrome

    Directory of Open Access Journals (Sweden)

    Hemmat Morteza

    2012-06-01

    Full Text Available Abstract Background Neocentromeres are rare human chromosomal aberrations in which a new centromere has formed in a previously non-centromeric location. We report the finding of a structurally abnormal X chromosome with a neocentromere in a 15-year-old girl with clinical features suggestive of Turner syndrome, including short stature and primary amenorrhea. Result G-banded chromosome analysis revealed a mosaic female karyotype involving two abnormal cell lines. One cell line (84% of analyzed metaphases had a structurally abnormal X chromosome (duplication of the long arm and deletion of the short arm and a normal X chromosome. The other cell line (16% of cells exhibited monosomy X. C-banding studies were negative for the abnormal X chromosome. FISH analysis revealed lack of hybridization of the abnormal X chromosome with both the X centromere-specific probe and the “all human centromeres” probe, a pattern consistent with lack of the X chromosome endogenous centromere. A FISH study using an XIST gene probe revealed the presence of two XIST genes, one on each long arm of the iso(Xq, required for inactivation of the abnormal X chromosome. R-banding also demonstrated inactivation of the abnormal X chromosome. An assay for centromeric protein C (CENP-C was positive on both the normal and the abnormal X chromosomes. The position of CENP-C in the abnormal X chromosome defined a neocentromere, which explains its mitotic stability. The karyotype is thus designated as 46,X,neo(X(qter- > q12::q12- > q21.2- > neo- > q21.2- > qter[42]/45,X[8], which is consistent with stigmata of Turner syndrome. The mother of this patient has a normal karyotype; however, the father was not available for study. Conclusion To our knowledge, this is the first case of mosaic Turner syndrome involving an analphoid iso(Xq chromosome with a proven neocentromere among 90 previously described cases with a proven neocentromere.

  3. Dosage compensation and demasculinization of X chromosomes in Drosophila.

    Science.gov (United States)

    Bachtrog, Doris; Toda, Nicholas R T; Lockton, Steven

    2010-08-24

    The X chromosome of Drosophila shows a deficiency of genes with male-biased expression, whereas mammalian X chromosomes are enriched for spermatogenesis genes expressed premeiosis and multicopy testis genes. Meiotic X-inactivation and sexual antagonism can only partly account for these patterns. Here, we show that dosage compensation (DC) in Drosophila may contribute substantially to the depletion of male genes on the X. To equalize expression between X-linked and autosomal genes in the two sexes, male Drosophila hypertranscribe their single X, whereas female mammals silence one of their two X chromosomes. We combine fine-scale mapping data of dosage compensated regions with genome-wide expression profiles and show that most male-biased genes on the D. melanogaster X are located outside dosage compensated regions. Additionally, X-linked genes that have newly acquired male-biased expression in D. melanogaster are less likely to be dosage compensated, and parental X-linked genes that gave rise to an autosomal male-biased retrocopy are more likely located within compensated regions. This suggests that DC contributes to the observed demasculinization of X chromosomes in Drosophila, both by limiting the emergence of male-biased expression patterns of existing X genes, and by contributing to gene trafficking of male genes off the X. Copyright 2010 Elsevier Ltd. All rights reserved.

  4. Tumor-suppressor genes that escape from X-inactivation contribute to cancer sex bias.

    Science.gov (United States)

    Dunford, Andrew; Weinstock, David M; Savova, Virginia; Schumacher, Steven E; Cleary, John P; Yoda, Akinori; Sullivan, Timothy J; Hess, Julian M; Gimelbrant, Alexander A; Beroukhim, Rameen; Lawrence, Michael S; Getz, Gad; Lane, Andrew A

    2017-01-01

    There is a striking and unexplained male predominance across many cancer types. A subset of X-chromosome genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative 'escape from X-inactivation tumor-suppressor' (EXITS) genes, we examined somatic alterations from >4,100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) X-chromosome genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) harbored loss-of-function mutations more frequently in males (based on a false discovery rate < 0.1), in comparison to zero of 18,055 autosomal and PAR genes (Fisher's exact P < 0.0001). Male-biased mutations in genes that escape X-inactivation were observed in combined analysis across many cancers and in several individual tumor types, suggesting a generalized phenomenon. We conclude that biallelic expression of EXITS genes in females explains a portion of the reduced cancer incidence in females as compared to males across a variety of tumor types.

  5. Sex chromosome repeats tip the balance towards speciation.

    Science.gov (United States)

    O'Neill, Michael J; O'Neill, Rachel J

    2018-04-06

    Because sex chromosomes, by definition, carry genes that determine sex, mutations that alter their structural and functional stability can have immediate consequences for the individual by reducing fertility, but also for a species by altering the sex ratio. Moreover, the sex-specific segregation patterns of heteromorphic sex chromosomes make them havens for selfish genetic elements that not only create sub-optimal sex ratios, but can also foster sexual antagonism. Compensatory mutations to mitigate antagonism or return sex ratios to a Fisherian optimum can create hybrid incompatibility and establish reproductive barriers leading to species divergence. The destabilizing influence of these selfish elements is often manifest within populations as copy number variants (CNVs) in satellite repeats and transposable elements (TE) or as CNVs involving sex determining genes, or genes essential to fertility and sex chromosome dosage compensation. This review catalogs several examples of well-studied sex chromosome CNVs in Drosophilids and mammals that underlie instances of meiotic drive, hybrid incompatibility and disruptions to sex differentiation and sex chromosome dosage compensation. While it is difficult to pinpoint a direct cause/effect relationship between these sex chromosome CNVs and speciation, it is easy to see how their effects in creating imbalances between the sexes, and the compensatory mutations to restore balance, can lead to lineage splitting and species formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. Radiobiological inactivation of Epstein-Barr virus

    International Nuclear Information System (INIS)

    Henderson, E.; Heston, L.; Grogan, E.; Miller, G.

    1978-01-01

    Lymphocyte transforming properties of B95-8 strain Epstein-Barr virus (EBV) are very sensitive to inactivation by either uv or x irradiation. No dose of irradiation increases the transforming capacity of EBV. The x-ray dose needed for inactivation of EBV transformation (dose that results in 37% survival, 60,000 rads) is similar to the dose required for inactivation of plaque formation by herpes simplex virus type 1 (Fischer strain). Although herpes simplex virus is more sensitive than EBV to uv irradiation, this difference is most likely due to differences in the kinetics or mechanisms of repair of uv damage to the two viruses. The results lead to the hypothesis that a large part, or perhaps all, of the EBV genome is in some way needed to initiate transformation. The abilities of EBV to stimulate host cell DNA synthesis, to induce nuclear antigen, and to immortalize are inactivated in parallel. All clones of marmoset cells transformed by irradiated virus produce extracellular transforming virus. These findings suggest that the abilities of the virus to transform and to replicate complete progeny are inactivated together. The amounts of uv and x irradiation that inactivate transformation by B95-8 virus are less than the dose needed to inactivate early antigen induction by the nontransforming P 3 HR-1 strain of EBV. Based on radiobiological inactivation, 10 to 50% of the genome is needed for early antigen induction

  7. Characterizing the Final Steps of Chromosomal Replication at the Single-molecule Level in the Model System Escherichia coli

    KAUST Repository

    Elshenawy, Mohamed

    2015-01-01

    In the circular Escherichia coli chromosome, two replisomes are assembled at the unique origin of replication and drive DNA synthesis in opposite directions until they meet in the terminus region across from the origin. Despite the difference

  8. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    Directory of Open Access Journals (Sweden)

    Liliana Costa

    2012-06-01

    Full Text Available Photodynamic inactivation (PDI has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.

  9. Evaluation of X-Inactivation Status and Cytogenetic Stability of Human Dermal Fibroblasts after Long-Term Culture

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Xue

    2010-01-01

    Full Text Available Human primary fibroblasts are a popular type of somatic cells for the production of induced pluripotent stem (iPS cells. Here we characterized biological properties of primary fibroblasts in terms of cell-growth rate, cytogenetic stability, and the number of inactive X chromosomes during long-term passaging. We produced eight lines of female human dermal fibroblasts (HDFs and found normal karyotype and expected pattern of X chromosome inactivation (XCI at low passages (Passage P1-5. However, four out of the eight HDF lines at high passage numbers (≥P10 exhibited duplicated hallmarks of inactive X chromosome including two punctuate signals of histone H3 lysine 27 trimethylation (H3K27me3 and X inactive-specific transcript (XIST RNA signals in approximately 8.5–18.5% of the cells. Our data suggest that the copy number of inactive X chromosomes in a subset of female HDF is increased by a two-fold. Consistently, DNA fluorescent in situ hybridization (FISH identified 3-4 copies of X chromosomes in one nucleus in this subset of cells with two inactive Xs. We conclude that female HDF cultures exhibit a higher risk of genetic anomalies such as carrying an increased number of X chromosomes including both active and inactive X chromosomes at a high passage (≥P10.

  10. Female-biased expression of long non-coding RNAs in domains that escape X-inactivation in mouse

    Directory of Open Access Journals (Sweden)

    Lu Lu

    2010-11-01

    Full Text Available Abstract Background Sexual dimorphism in brain gene expression has been recognized in several animal species. However, the relevant regulatory mechanisms remain poorly understood. To investigate whether sex-biased gene expression in mammalian brain is globally regulated or locally regulated in diverse brain structures, and to study the genomic organisation of brain-expressed sex-biased genes, we performed a large scale gene expression analysis of distinct brain regions in adult male and female mice. Results This study revealed spatial specificity in sex-biased transcription in the mouse brain, and identified 173 sex-biased genes in the striatum; 19 in the neocortex; 12 in the hippocampus and 31 in the eye. Genes located on sex chromosomes were consistently over-represented in all brain regions. Analysis on a subset of genes with sex-bias in more than one tissue revealed Y-encoded male-biased transcripts and X-encoded female-biased transcripts known to escape X-inactivation. In addition, we identified novel coding and non-coding X-linked genes with female-biased expression in multiple tissues. Interestingly, the chromosomal positions of all of the female-biased non-coding genes are in close proximity to protein-coding genes that escape X-inactivation. This defines X-chromosome domains each of which contains a coding and a non-coding female-biased gene. Lack of repressive chromatin marks in non-coding transcribed loci supports the possibility that they escape X-inactivation. Moreover, RNA-DNA combined FISH experiments confirmed the biallelic expression of one such novel domain. Conclusion This study demonstrated that the amount of genes with sex-biased expression varies between individual brain regions in mouse. The sex-biased genes identified are localized on many chromosomes. At the same time, sexually dimorphic gene expression that is common to several parts of the brain is mostly restricted to the sex chromosomes. Moreover, the study uncovered

  11. Deletion of an X-inactivation boundary disrupts adjacent gene silencing.

    Directory of Open Access Journals (Sweden)

    Lindsay M Horvath

    2013-11-01

    Full Text Available In mammalian females, genes on one X are largely silenced by X-chromosome inactivation (XCI, although some "escape" XCI and are expressed from both Xs. Escapees can closely juxtapose X-inactivated genes and provide a tractable model for assessing boundary function at epigenetically regulated loci. To delimit sequences at an XCI boundary, we examined female mouse embryonic stem cells carrying X-linked BAC transgenes derived from an endogenous escape locus. Previously we determined that large BACs carrying escapee Kdm5c and flanking X-inactivated transcripts are properly regulated. Here we identify two lines with truncated BACs that partially and completely delete the distal Kdm5c XCI boundary. This boundary is not required for escape, since despite integrating into regions that are normally X inactivated, transgenic Kdm5c escapes XCI, as determined by RNA FISH and by structurally adopting an active conformation that facilitates long-range preferential association with other escapees. Yet, XCI regulation is disrupted in the transgene fully lacking the distal boundary; integration site genes up to 350 kb downstream of the transgene now inappropriately escape XCI. Altogether, these results reveal two genetically separable XCI regulatory activities at Kdm5c. XCI escape is driven by a dominant element(s retained in the shortest transgene that therefore lies within or upstream of the Kdm5c locus. Additionally, the distal XCI boundary normally plays an essential role in preventing nearby genes from escaping XCI.

  12. Molecular fundamentals of chromosomal mutagenesis

    International Nuclear Information System (INIS)

    Ganassi, E.Eh.; Zaichkina, S.I.; Malakhova, L.V.

    1987-01-01

    Precise quantitative correlation between the yield of chromosome structure damages and the yield of DNA damages is shown when comparing data on molecular and cytogenetic investigations carried out in cultural Mammalia cells. As the chromosome structure damage is to be connected with the damage of its carcass structure, then it is natural that DNA damage in loop regions is not to affect considerably the structure, while DNA damage lying on the loop base and connected with the chromosome carcass is to play a determining role in chromosomal mutagenesis. This DNA constitutes 1-2% from the total quantity of nuclear DNA. If one accepts that damages of these regions of DNA are ''hot'' points of chromosomal mutagenesis, then it becomes clear why 1-2% of preparation damages in a cell are realized in chromosome structural damages

  13. The Role of Dicentric Chromosome Formation and Secondary Centromere Deletion in the Evolution of Myeloid Malignancy

    Science.gov (United States)

    MacKinnon, Ruth N.; Campbell, Lynda J.

    2011-01-01

    Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes, together with other unrecognized dicentric chromosomes, points to a greater role for dicentric chromosomes in cancer initiation and progression than is generally acknowledged. We present a model that predicts and explains a significant role for dicentric chromosomes in the formation of unbalanced translocations in malignancy. PMID:22567363

  14. The Role of Dicentric Chromosome Formation and Secondary Centromere Deletion in the Evolution of Myeloid Malignancy

    Directory of Open Access Journals (Sweden)

    Ruth N. MacKinnon

    2011-01-01

    Full Text Available Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes, together with other unrecognized dicentric chromosomes, points to a greater role for dicentric chromosomes in cancer initiation and progression than is generally acknowledged. We present a model that predicts and explains a significant role for dicentric chromosomes in the formation of unbalanced translocations in malignancy.

  15. Weird mammals provide insights into the evolution of mammalian sex chromosomes and dosage compensation.

    Science.gov (United States)

    Graves, Jennifer A Marshall

    2015-12-01

    The deep divergence of mammalian groups 166 and 190 million years ago (MYA) provide genetic variation to explore the evolution of DNA sequence, gene arrangement and regulation of gene expression in mammals. With encouragement from the founder of the field, Mary Lyon, techniques in cytogenetics and molecular biology were progressively adapted to characterize the sex chromosomes of kangaroos and other marsupials, platypus and echidna-and weird rodent species. Comparative gene mapping reveals the process of sex chromosome evolution from their inception 190 MYA (they are autosomal in platypus) to their inevitable end (the Y has disappeared in two rodent lineages). Our X and Y are relatively young, getting their start with the evolution of the sex-determining SRY gene, which triggered progressive degradation of the Y chromosome. Even more recently, sex chromosomes of placental mammals fused with an autosomal region which now makes up most of the Y. Exploration of gene activity patterns over four decades showed that dosage compensation via X-chromosome inactivation is unique to therian mammals, and that this whole chromosome control process is different in marsupials and absent in monotremes and reptiles, and birds. These differences can be exploited to deduce how mammalian sex chromosomes and epigenetic silencing evolved.

  16. Intraspecific chromosome variability

    Directory of Open Access Journals (Sweden)

    N Dubinin

    2010-12-01

    Full Text Available (Editorial preface. The publication is presented in order to remind us of one of dramatic pages of the history of genetics. It re-opens for the contemporary reader a comprehensive work marking the priority change from plant cytogenetics to animal cytogenetics led by wide population studies which were conducted on Drosophila polytene chromosomes. The year of the publication (1937 became the point of irretrievable branching between the directions of Old World and New World genetics connected with the problems of chromosome variability and its significance for the evolution of the species. The famous book of T. Dobzhansky (1937 was published by Columbia University in the US under the title “Genetics and the origin of species”, and in the shadow of this American ‘skybuilding’ all other works grew dim. It is remarkable that both Dobzhansky and Dubinin come to similar conclusions about the role of chromosomes in speciation. This is not surprising given that they both might be considered as representatives of the Russian genetic school, by their birth and education. Interestingly, Dobzhansky had never referred to the full paper of Dubinin et al. (1937, though a previous short communication in Nature (1936 was included together with all former papers on the related subject. In full, the volume of the original publication printed in the Biological Journal in Moscow comprised 47 pages, in that number 41 pages of the Russian text accompanied by 16 Figs, a table and reference list, and, above all, 6 pages of the English summary. This final part in English is now reproduced in the authors’ version with the only addition being the reference list in the originally printed form.

  17. Hormad1 mutation disrupts synaptonemal complex formation, recombination, and chromosome segregation in mammalian meiosis.

    Directory of Open Access Journals (Sweden)

    Yong-Hyun Shin

    2010-11-01

    Full Text Available Meiosis is unique to germ cells and essential for reproduction. During the first meiotic division, homologous chromosomes pair, recombine, and form chiasmata. The homologues connect via axial elements and numerous transverse filaments to form the synaptonemal complex. The synaptonemal complex is a critical component for chromosome pairing, segregation, and recombination. We previously identified a novel germ cell-specific HORMA domain encoding gene, Hormad1, a member of the synaptonemal complex and a mammalian counterpart to the yeast meiotic HORMA domain protein Hop1. Hormad1 is essential for mammalian gametogenesis as knockout male and female mice are infertile. Hormad1 deficient (Hormad1(-/ (- testes exhibit meiotic arrest in the early pachytene stage, and synaptonemal complexes cannot be visualized by electron microscopy. Hormad1 deficiency does not affect localization of other synaptonemal complex proteins, SYCP2 and SYCP3, but disrupts homologous chromosome pairing. Double stranded break formation and early recombination events are disrupted in Hormad1(-/ (- testes and ovaries as shown by the drastic decrease in the γH2AX, DMC1, RAD51, and RPA foci. HORMAD1 co-localizes with γH2AX to the sex body during pachytene. BRCA1, ATR, and γH2AX co-localize to the sex body and participate in meiotic sex chromosome inactivation and transcriptional silencing. Hormad1 deficiency abolishes γH2AX, ATR, and BRCA1 localization to the sex chromosomes and causes transcriptional de-repression on the X chromosome. Unlike testes, Hormad1(-/ (- ovaries have seemingly normal ovarian folliculogenesis after puberty. However, embryos generated from Hormad1(-/ (- oocytes are hyper- and hypodiploid at the 2 cell and 8 cell stage, and they arrest at the blastocyst stage. HORMAD1 is therefore a critical component of the synaptonemal complex that affects synapsis, recombination, and meiotic sex chromosome inactivation and transcriptional silencing.

  18. Assessment of chromosomal imbalances in CIMP-high and CIMP-low/CIMP-0 colorectal cancers.

    Science.gov (United States)

    Kozlowska, Joanna; Karpinski, Pawel; Szmida, Elzbieta; Laczmanska, Izabela; Misiak, Blazej; Ramsey, David; Bebenek, Marek; Kielan, Wojciech; Pesz, Karolina A; Sasiadek, Maria M

    2012-08-01

    Data presented in a number of recent studies have revealed a negative correlation between CpG island methylator phenotype (CIMP) and chromosomal instability (CIN) measured by a loss of heterozygosity (LOH) of selected loci, suggesting that CIN and CIMP represent two independent mechanisms in sporadic colorectal cancer (CRC) carcinogenesis. However, CIN is a heterogeneous phenomenon, which may be studied not only by employing LOH analysis but also by observing chromosomal imbalances (gains and deletions). The current study aimed to investigate the relationship between CIMP and chromosomal gains and deletions (assessed by comparative genomic hybridization) in a group of 20 CIMP-high and 79 CIMP-low/CIMP-0 CRCs. Our results revealed that the mean numbers of gains and of total chromosomal imbalances were significantly greater (p = 0.004 and p = 0.007, respectively) in the CIMP-low/CIMP-0 group compared to the CIMP-high group, while no significant difference was observed between the mean numbers of losses (p = 0.056). The analysis of copy number changes of 41 cancer-related genes by multiplex ligation-dependent probe amplification showed that CRK gene was exclusively deleted in CIMP-low/CIMP-0 tumors (p = 0.02). Given that chromosomal losses play an important role in tumor suppressor inactivation and chromosomal gains, in the activation of proto-oncogenes, we hypothesize that tumor suppressor inactivation plays similar roles in both CIMP-high and CIMP-low/CIMP-0 CRCs, while the predominance of chromosomal gains in CIMP-low/CIMP-0 tumors may suggest that the activation of proto-oncogenes is the underlying mechanism of CIMP-low/CIMP-0 CRC progression.

  19. Mandatory chromosomal segment balance in aneuploid tumor cells

    International Nuclear Information System (INIS)

    Kost-Alimova, Maria; Stanbridge, Eric; Klein, George; Imreh, Stefan; Darai-Ramqvist, Eva; Yau, Wing Lung; Sandlund, Agneta; Fedorova, Ludmila; Yang, Ying; Kholodnyuk, Irina; Cheng, Yue; Li Lung, Maria

    2007-01-01

    Euploid chromosome balance is vitally important for normal development, but is profoundly changed in many tumors. Is each tumor dependent on its own structurally and numerically changed chromosome complement that has evolved during its development and progression? We have previously shown that normal chromosome 3 transfer into the KH39 renal cell carcinoma line and into the Hone1 nasopharyngeal carcinoma line inhibited their tumorigenicity. The aim of the present study was to distinguish between a qualitative and a quantitative model of this suppression. According to the former, a damaged or deleted tumor suppressor gene would be restored by the transfer of a normal chromosome. If so, suppression would be released only when the corresponding sequences of the exogenous normal chromosome are lost or inactivated. According to the alternative quantitative model, the tumor cell would not tolerate an increased dosage of the relevant gene or segment. If so, either a normal cell derived, or, a tumor derived endogenous segment could be lost. Fluorescence in Situ Hybridization based methods, as well as analysis of polymorphic microsatellite markers were used to follow chromosome 3 constitution changes in monochromosomal hybrids. In both tumor lines with introduced supernumerary chromosomes 3, the copy number of 3p21 or the entire 3p tended to fall back to the original level during both in vitro and in vivo growth. An exogenous, normal cell derived, or an endogenous, tumor derived, chromosome segment was lost with similar probability. Identification of the lost versus retained segments showed that the intolerance for increased copy number was particularly strong for 3p14-p21, and weaker for other 3p regions. Gains in copy number were, on the other hand, well tolerated in the long arm and particularly the 3q26-q27 region. The inability of the cell to tolerate an experimentally imposed gain in 3p14-p21 in contrast to the well tolerated gain in 3q26-q27 is consistent with the

  20. X chromosome and suicide.

    Science.gov (United States)

    Fiori, L M; Zouk, H; Himmelman, C; Turecki, G

    2011-02-01

    Suicide completion rates are significantly higher in males than females in most societies. Although gender differences in suicide rates have been partially explained by environmental and behavioral factors, it is possible that genetic factors, through differential expression between genders, may also help explain gender moderation of suicide risk. This study investigated X-linked genes in suicide completers using a two-step strategy. We first took advantage of the genetic structure of the French-Canadian population and genotyped 722 unrelated French-Canadian male subjects, of whom 333 were suicide completers and 389 were non-suicide controls, using a panel of 37 microsatellite markers spanning the entire X chromosome. Nine haplotype windows and several individual markers were associated with suicide. Significant results aggregated primarily in two regions, one in the long arm and another in the short arm of chromosome X, limited by markers DXS8051 and DXS8102, and DXS1001 and DXS8106, respectively. The second stage of the study investigated differential brain expression of genes mapping to associated regions in Brodmann areas 8/9, 11, 44 and 46, in an independent sample of suicide completers and controls. Six genes within these regions, Rho GTPase-activating protein 6, adaptor-related protein complex 1 sigma 2 subunit, glycoprotein M6B, ribosomal protein S6 kinase 90  kDa polypeptide 3, spermidine/spermine N(1)-acetyltransferase 1 and THO complex 2, were found to be differentially expressed in suicide completers.

  1. Extended driving impairs nocturnal driving performances.

    Directory of Open Access Journals (Sweden)

    Patricia Sagaspe

    Full Text Available Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3-5 am, 1-5 am and 9 pm-5 am on open highway. Fourteen young healthy men (mean age [+/-SD] = 23.4 [+/-1.7] years participated Inappropriate line crossings (ILC in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3-5 am driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05 for the intermediate (1-5 am driving session and by 4.0 (CI, 1.7 to 9.4; P<.001 for the long (9 pm-5 am driving session. Compared to the reference session (9-10 pm, the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001, 15.4 (CI, 4.6 to 51.5; P<.001 and 24.3 (CI, 7.4 to 79.5; P<.001, respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05 and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01. At night, extended driving impairs driving performances and therefore should be limited.

  2. Chromosome Connections: Compelling Clues to Common Ancestry

    Science.gov (United States)

    Flammer, Larry

    2013-01-01

    Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…

  3. New Y chromosomes and early stages of sex chromosome ...

    Indian Academy of Sciences (India)

    2010-09-06

    Sep 6, 2010 ... chromosomes are evolutionary consequences of that func- tion. Given sufficient ... (for a review, see Charlesworth et al. 2005). ... In the present paper, I review sex deter- mination .... part had apparently been exchanged against the homologous ... age group III-Y chromosomes were successful while in well-.

  4. Pure chromosome-specific PCR libraries from single sorted chromosomes

    NARCIS (Netherlands)

    VanDevanter, D. R.; Choongkittaworn, N. M.; Dyer, K. A.; Aten, J. A.; Otto, P.; Behler, C.; Bryant, E. M.; Rabinovitch, P. S.

    1994-01-01

    Chromosome-specific DNA libraries can be very useful in molecular and cytogenetic genome mapping studies. We have developed a rapid and simple method for the generation of chromosome-specific DNA sequences that relies on polymerase chain reaction (PCR) amplification of a single flow-sorted

  5. Rumex acetosa Y chromosomes: constitutive or facultative heterochromatin?

    Directory of Open Access Journals (Sweden)

    Andrzej J. Joachimiak

    2011-08-01

    Full Text Available Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw. Stearn roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.

  6. Level of heat shock proteins decreases in individuals carrying B-chromosomes in the grasshopper Eyprepocnemis plorans

    DEFF Research Database (Denmark)

    Teruel, M; Sørensen, Jesper Givskov; Loeschcke, Volker

    2010-01-01

    We analyzed the effect of B-chromosome presence on expression level of heat shock protein 70 (Hsp70) in cerebral ganglion and gonad in both males and females of the grasshopper Eyprepocnemis plorans. Two natural Spanish populations, Salobreña (Granada) and Torrox (Málaga) were assayed, the former...... harbouring a neutralized (non-driving) B-chromosome (B2) and the latter a parasitic (driving) B-chromosome (B24). The analysis was performed by Western blotting, immunostaining and densitometric measuring expression level of the Hsp70 family in adult individuals. The results showed that Hsp70 levels...

  7. A role for a neo-sex chromosome in stickleback speciation

    Science.gov (United States)

    Kitano, Jun; Ross, Joseph A.; Mori, Seiichi; Kume, Manabu; Jones, Felicity C.; Chan, Yingguang F.; Absher, Devin M.; Grimwood, Jane; Schmutz, Jeremy; Myers, Richard M.; Kingsley, David M.; Peichel, Catherine L.

    2009-01-01

    Sexual antagonism, or conflict between the sexes, has been proposed as a driving force in both sex chromosome turnover and speciation. Although closely related species often have different sex chromosome systems, it is unknown whether sex chromosome turnover contributes to the evolution of reproductive isolation between species. In this study, we show that a newly evolved sex chromosome harbours genes that contribute to speciation in threespine stickleback fish (Gasterosteus aculeatus). We first identified a neo-sex chromosome system found only in one member of a sympatric species pair in Japan. We then performed genetic linkage mapping of male-specific traits important for reproductive isolation between the Japanese species pair. The neo-X chromosome harbours loci for male courtship display traits that contribute to behavioural isolation, while the ancestral X chromosome contains loci for both behavioural isolation and hybrid male sterility. Our work not only provides strong evidence for a large-X effect on reproductive isolation in a vertebrate system, but also provides direct evidence that a young neo-X chromosome contributes to reproductive isolation between closely related species. Our data suggest that sex chromosome turnover might play a greater role in speciation than previously appreciated. PMID:19783981

  8. HARMONIC DRIVE SELECTION

    Directory of Open Access Journals (Sweden)

    Piotr FOLĘGA

    2014-03-01

    Full Text Available The variety of types and sizes currently in production harmonic drive is a problem in their rational choice. Properly selected harmonic drive must meet certain requirements during operation, and achieve the anticipated service life. The paper discusses the problems associated with the selection of the harmonic drive. It also presents the algorithm correct choice of harmonic drive. The main objective of this study was to develop a computer program that allows the correct choice of harmonic drive by developed algorithm.

  9. Cohesin in determining chromosome architecture

    Energy Technology Data Exchange (ETDEWEB)

    Haering, Christian H., E-mail: christian.haering@embl.de [Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg (Germany); Jessberger, Rolf, E-mail: rolf.jessberger@tu-dresden.de [Institute of Physiological Chemistry, Dresden University of Technology, Dresden (Germany)

    2012-07-15

    Cells use ring-like structured protein complexes for various tasks in DNA dynamics. The tripartite cohesin ring is particularly suited to determine chromosome architecture, for it is large and dynamic, may acquire different forms, and is involved in several distinct nuclear processes. This review focuses on cohesin's role in structuring chromosomes during mitotic and meiotic cell divisions and during interphase.

  10. Sex chromosomes in Ephestia kuehniella

    Czech Academy of Sciences Publication Activity Database

    Marec, František; Sahara, K.; Traut, W.

    2001-01-01

    Roč. 44, č. 1 (2001), s. 131 ISSN 0003-3995. [European Cytogenetics Conference /3./. 07.07.2001-10.07.2001, Paris] Institutional research plan: CEZ:AV0Z5007907 Keywords : Telomere * sex chromosomes * chromosome fragments Subject RIV: EB - Genetics ; Molecular Biology

  11. Slit scan flow cytometry of isolated chromosomes following fluorescence hybridization: an approach of online screening for specific chromosomes and chromosome translocations

    NARCIS (Netherlands)

    Hausmann, M.; Dudin, G.; Aten, J. A.; Heilig, R.; Diaz, E.; Cremer, C.

    1991-01-01

    The recently developed methods of non radioactive in situ hybridization of chromosomes offer new aspects for chromosome analysis. Fluorescent labelling of hybridized chromosomes or chromosomal subregions allows to facilitate considerably the detection of specific chromosomal abnormalities. For many

  12. Physical inactivation and stabilization of sludges

    International Nuclear Information System (INIS)

    Alexandre, D.

    1979-07-01

    High temperature conditioning of sludge is a stabilization process that insures sterilization. Both thermal pasteurization and irradiation are inactivation processes. Viruses and parasites are inactivated at 70-80 0 C. Total bacterial destruction requires higher temperatures and/or detention time. Radio sensitivity of pathogens and pertinent treatment parameters are examined. If sludge is to be land disposed, disinfection requires irradiation doses ranging 500 Krad; if cattle feeding is considered, the required dose is 1 Mrad

  13. Microbial Inactivation by Ultrasound Assisted Supercritical Fluids

    Science.gov (United States)

    Benedito, Jose; Ortuño, Carmen; Castillo-Zamudio, Rosa Isela; Mulet, Antonio

    A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.

  14. Mycobacteria inactivation using Engineered Water Nanostructures (EWNS).

    Science.gov (United States)

    Pyrgiotakis, Georgios; McDevitt, James; Gao, Ya; Branco, Alan; Eleftheriadou, Mary; Lemos, Bernardo; Nardell, Edward; Demokritou, Philip

    2014-08-01

    Airborne transmitted pathogens such as Mycobacterium tuberculosis (Mtb) cause serious, often fatal infectious disease with enormous global health implications. Due to their unique cell wall and slow growth, mycobacteria are among the most resilient microbial forms. Herein we evaluate the ability of an emerging, chemical-free, nanotechnology-based method to inactivate M. parafortuitum (Mtb surrogate). This method is based on the transformation of atmospheric water vapor into engineered water nano-structures (EWNS) via electrospray. We demonstrate that the EWNS can interact with and inactivate airborne mycobacteria, reducing their concentration levels significantly. Additionally, EWNS can inactivate M. parafortuitum on surfaces eight times faster than the control. The mechanism of mycobacteria inactivation was also investigated in this study. It was demonstrated that the EWNS effectively deliver the reactive oxygen species, encapsulated during the electrospray process, to the bacteria oxidizing their cell membrane resulting into inactivation. Overall, this is a method with the potential to become an effective intervention technology in the battle against airborne infections. This study demonstrates the feasibility of mycobacterium inactivation in airborne form or on contact surfaces using electrospray activated water nano-structures. Given that the method is free of toxic chemicals, this might become an important tool in the prevention of mycobacterial infections, which are notoriously hard to treat. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Cell inactivation by heavy charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Blakely, E A [Lawrence Berkeley Lab., CA (United States). Cell and Molecular Biology Div.

    1992-06-01

    The inactivation of cells resulting in lethal or aberrant effects by charged particles is of growing interest. Charged particles at extremely high LET are capable of completely eliminating cell-type and cell-line differences in repair capacity. It is still not clear however whether the repair systems are inactivated, or merely that heavy-ion lesions are less repairable. Studies correlating the particle inactivation dose of radioresistant cells with intact DNA analyzed with pulse field gel electrophoresis and other techniques may be useful, but more experiments are also needed to assess the fidelity of repair. For particle irradiations between 40-100 keV/{mu}m there is however evidence for particle-induced activation of specific genes in mammalian cells, and certain repair processes in bacteria. New data are available on the inactivation of developmental processes in several systems including seeds, and cells of the nematode C. elegans. Future experimental and theoretical modeling research emphasis should focus on exploring particle-induced inactivation of endpoints assessing functionality and not just lethality, and on analyzing molecular damage and genetic effects arising in damage but non-inactivated survivors. The discrete nature of selective types of particle damage as a function of radiation quality indicates the value of accelerated ions as probes of normal and aberrant biological processes. Information obtained from molecular analyses of damage and repair must however be integrated into the context of cellular and tissue functions of the organism. (orig.).

  16. Rapid neo-sex chromosome evolution and incipient speciation in a major forest pest.

    Science.gov (United States)

    Bracewell, Ryan R; Bentz, Barbara J; Sullivan, Brian T; Good, Jeffrey M

    2017-11-17

    Genome evolution is predicted to be rapid following the establishment of new (neo) sex chromosomes, but it is not known if neo-sex chromosome evolution plays an important role in speciation. Here we combine extensive crossing experiments with population and functional genomic data to examine neo-XY chromosome evolution and incipient speciation in the mountain pine beetle. We find a broad continuum of intrinsic incompatibilities in hybrid males that increase in strength with geographic distance between reproductively isolated populations. This striking progression of reproductive isolation is coupled with extensive gene specialization, natural selection, and elevated genetic differentiation on both sex chromosomes. Closely related populations isolated by hybrid male sterility also show fixation of alternative neo-Y haplotypes that differ in structure and male-specific gene content. Our results suggest that neo-sex chromosome evolution can drive rapid functional divergence between closely related populations irrespective of ecological drivers of divergence.

  17. Schizophrenia and chromosomal deletions

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, E.A.; Baldini, A. [Baylor College of Medicine, Houston, TX (United States); Morris, M. A. [Univ. of Geneva School of Medicine, NY (United States)] [and others

    1995-06-01

    Recent genetic linkage analysis studies have suggested the presence of a schizophrenia locus on the chromosomal region 22q11-q13. Schizophrenia has also been frequently observed in patients affected with velo-cardio-facial syndrome (VCFS), a disorder frequently associated with deletions within 22q11.1. It has been hypothesized that psychosis in VCFS may be due to deletion of the catechol-o-methyl transferase gene. Prompted by these observations, we screened for 22q11 deletions in a population of 100 schizophrenics selected from the Maryland Epidemiological Sample. Our results show that there are schizophrenic patients carrying a deletion of 22q11.1 and a mild VCFS phenotype that might remain unrecognized. These findings should encourage a search for a schizophrenia-susceptibility gene within the deleted region and alert those in clinical practice to the possible presence of a mild VCFS phenotype associated with schizophrenia. 9 refs.

  18. Mitotic chromosome condensation in vertebrates

    International Nuclear Information System (INIS)

    Vagnarelli, Paola

    2012-01-01

    Work from several laboratories over the past 10–15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292–301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories—a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307–316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119–1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579–589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different

  19. Mitotic chromosome condensation in vertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Vagnarelli, Paola, E-mail: P.Vagnarelli@ed.ac.uk

    2012-07-15

    Work from several laboratories over the past 10-15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292-301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories-a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307-316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119-1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579-589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different classes

  20. Binding of Multiple Rap1 Proteins Stimulates Chromosome Breakage Induction during DNA Replication.

    Directory of Open Access Journals (Sweden)

    Greicy H Goto

    2015-08-01

    Full Text Available Telomeres, the ends of linear eukaryotic chromosomes, have a specialized chromatin structure that provides a stable chromosomal terminus. In budding yeast Rap1 protein binds to telomeric TG repeat and negatively regulates telomere length. Here we show that binding of multiple Rap1 proteins stimulates DNA double-stranded break (DSB induction at both telomeric and non-telomeric regions. Consistent with the role of DSB induction, Rap1 stimulates nearby recombination events in a dosage-dependent manner. Rap1 recruits Rif1 and Rif2 to telomeres, but neither Rif1 nor Rif2 is required for DSB induction. Rap1-mediated DSB induction involves replication fork progression but inactivation of checkpoint kinase Mec1 does not affect DSB induction. Rap1 tethering shortens artificially elongated telomeres in parallel with telomerase inhibition, and this telomere shortening does not require homologous recombination. These results suggest that Rap1 contributes to telomere homeostasis by promoting chromosome breakage.

  1. Delineation and analysis of chromosomal regions specifying Yersinia pestis.

    Science.gov (United States)

    Derbise, Anne; Chenal-Francisque, Viviane; Huon, Christèle; Fayolle, Corinne; Demeure, Christian E; Chane-Woon-Ming, Béatrice; Médigue, Claudine; Hinnebusch, B Joseph; Carniel, Elisabeth

    2010-09-01

    Yersinia pestis, the causative agent of plague, has recently diverged from the less virulent enteropathogen Yersinia pseudotuberculosis. Its emergence has been characterized by massive genetic loss and inactivation and limited gene acquisition. The acquired genes include two plasmids, a filamentous phage, and a few chromosomal loci. The aim of this study was to characterize the chromosomal regions acquired by Y. pestis. Following in silico comparative analysis and PCR screening of 98 strains of Y. pseudotuberculosis and Y. pestis, we found that eight chromosomal loci (six regions [R1pe to R6pe] and two coding sequences [CDS1pe and CDS2pe]) specified Y. pestis. Signatures of integration by site specific or homologous recombination were identified for most of them. These acquisitions and the loss of ancestral DNA sequences were concentrated in a chromosomal region opposite to the origin of replication. The specific regions were acquired very early during Y. pestis evolution and were retained during its microevolution, suggesting that they might bring some selective advantages. Only one region (R3pe), predicted to carry a lambdoid prophage, is most likely no longer functional because of mutations. With the exception of R1pe and R2pe, which have the potential to encode a restriction/modification and a sugar transport system, respectively, no functions could be predicted for the other Y. pestis-specific loci. To determine the role of the eight chromosomal loci in the physiology and pathogenicity of the plague bacillus, each of them was individually deleted from the bacterial chromosome. None of the deletants exhibited defects during growth in vitro. Using the Xenopsylla cheopis flea model, all deletants retained the capacity to produce a stable and persistent infection and to block fleas. Similarly, none of the deletants caused any acute flea toxicity. In the mouse model of infection, all deletants were fully virulent upon subcutaneous or aerosol infections. Therefore

  2. Inactivation of pathogenic bacteria in food matrices: high pressure processing, photodynamic inactivation and pressure-assisted photodynamic inactivation

    Science.gov (United States)

    Cunha, A.; Couceiro, J.; Bonifácio, D.; Martins, C.; Almeida, A.; Neves, M. G. P. M. S.; Faustino, M. A. F.; Saraiva, J. A.

    2017-09-01

    Traditional food processing methods frequently depend on the application of high temperature. However, heat may cause undesirable changes in food properties and often has a negative impact on nutritional value and organoleptic characteristics. Therefore, reducing the microbial load without compromising the desirable properties of food products is still a technological challenge. High-pressure processing (HPP) can be classified as a cold pasteurization technique, since it is a non-thermal food preservation method that uses hydrostatic pressure to inactivate spoilage microorganisms. At the same time, it increases shelf life and retains the original features of food. Photodynamic inactivation (PDI) is also regarded as promising approach for the decontamination of food matrices. In this case, the inactivation of bacterial cells is achieved by the cytotoxic effects of reactive oxygens species (ROS) produced from the combined interaction of a photosensitizer molecule, light and oxygen. This short review examines some recent developments on the application of HPP and PDI with food-grade photosensitizers for the inactivation of listeriae, taken as a food pathogen model. The results of a proof-of-concept trial of the use of high-pressure as a coadjutant to increase the efficiency of photodynamic inactivation of bacterial endospores is also addressed.

  3. Chromosome driven spatial patterning of proteins in bacteria.

    Directory of Open Access Journals (Sweden)

    Saeed Saberi

    Full Text Available The spatial patterning of proteins in bacteria plays an important role in many processes, from cell division to chemotaxis. In the asymmetrically dividing bacteria Caulobacter crescentus, a scaffolding protein, PopZ, localizes to both poles and aids the differential patterning of proteins between mother and daughter cells during division. Polar patterning of misfolded proteins in Escherichia coli has also been shown, and likely plays an important role in cellular ageing. Recent experiments on both of the above systems suggest that the presence of chromosome free regions along with protein multimerization may be a mechanism for driving the polar localization of proteins. We have developed a simple physical model for protein localization using only these two driving mechanisms. Our model reproduces all the observed patterns of PopZ and misfolded protein localization--from diffuse, unipolar, and bipolar patterns and can also account for the observed patterns in a variety of mutants. The model also suggests new experiments to further test the role of the chromosome in driving protein patterning, and whether such a mechanism is responsible for helping to drive the differentiation of the cell poles.

  4. Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

    Science.gov (United States)

    Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

    2013-07-08

    The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

  5. Interstitial deletion in the "critical region" of the long arm of the X chromosome in a mentally retarded boy and his normal mother

    DEFF Research Database (Denmark)

    Tabor, A; Andersen, O; Lundsteen, C

    1983-01-01

    A family in which an intestitial deletion of the X chromosome, del(X)(q13q21.3), is segregating was ascertained through a boy with cleft lip and palate, agenesis of the corpus callosum, and severe mental retardation. The possible causal relationship to his chromosome abnormality is discussed. Alt....... Although the deletion occurred within the critical region, the mother showed no signs of gonadal dysgenesis. A phenotypically normal daughter was, as her mother, monosomic for this region of the X, and both showed random inactivation of the X chromosome....

  6. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading.......Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading....

  7. Dementia and driving

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000028.htm Dementia and driving To use the sharing features on ... please enable JavaScript. If your loved one has dementia , deciding when they can no longer drive may ...

  8. Inactivation of enteroviruses in sewage with ozone

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, O.E.; Bogdanov, M.V.; Kazantseva, V.A.; Gabrilevskaia, L.N.; Kodkind, G.K.H.

    The study of ozone inactivation of enteroviruses in sewage showed the presence in sewage of suspensions of organic origin and bacterial flora to influence the rate of inactivation. The inactivation rate of poliomyelitis virus in sewage free from organic suspension and bacterial flora was significantly higher than that in sewage containing such suspension and bacterial flora. The inactivation rate of enteroviruses was found not to depend upon the protein and salt composition and pH of sewage or strain appurtenance of viruses. The inactivation rate of enteroviruses directly depended upon the dose of ozone and time of contact with it. Differences in the resistance of different types of poliomyelitis virus, ECHO and Coxsackie viruses to the effect of ozone are likely exist. These differences are manifested within the range of relatively small doses of ozone. E. coli is more resistant to ozone than entero-viruses. The results of laboratory studies were used to choose the regimen of sanitation of urban sewage to be used in technological cycles of industrial enterprises.

  9. Inactivation of Mycobacterium avium with free chlorine.

    Science.gov (United States)

    Luh, Jeanne; Mariñas, Benito J

    2007-07-15

    The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.

  10. Gear bearing drive

    Science.gov (United States)

    Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  11. Antihistamines and driving safety.

    Science.gov (United States)

    O'Hanlon, J F

    1988-10-27

    The results of two placebo-controlled driving performance studies confirm laboratory data showing that the nonsedating antihistamine terfenadine does not influence the driving performance of users. The amplitude of vehicle weaving calculated for drivers who received this agent did not differ from control values. Neither terfenadine nor loratadine, another nonsedating antihistamine, potentiated the adverse effects of alcohol on driving performance.

  12. Driving After a Stroke

    Science.gov (United States)

    ... 23,2015 Can I drive after a stroke? Driving is often a major concern after someone has a stroke. It’s not unusual for stroke survivors to want to drive. Being able to get around after a stroke is important. Safety behind the wheel is even more important after ...

  13. Sequential Dependencies in Driving

    Science.gov (United States)

    Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

    2012-01-01

    The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

  14. Simple Driving Techniques

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    2002-01-01

    -like language. Our aim is to extract a simple notion of driving and show that even in this tamed form it has much of the power of more general notions of driving. Our driving technique may be used to simplify functional programs which use function composition and will often be able to remove intermediate data...

  15. Chromosome fragility in Freemartin cattle

    Directory of Open Access Journals (Sweden)

    V. Barbieri

    2010-04-01

    Full Text Available The aim of the present study was to verify chromosome fragility in freemartin cattle using chromosome aberration (CA and sister chromatid exchange (SCE tests. A total of eighteen co-twins were investigated. Fourteen animals were identified as cytogenetically chimeric (2n=60, XX/XY while 4 were classified as normal. Freemartin cattle showed a higher percentage of aneuploid cells (18.64% and highly significant statistical differences (P < 0.001 in mean values of gaps (4.53 ± 2.05, chromatid breaks (0.26 ± 0.51, and significant statistical differences (P < 0.005 in mean values of chromosome breaks (0.12 ± 0.43 when compared to 10 control animals from single births (aneuploid cells, 11.20%; gaps, 2.01 ± 1.42; chromatid breaks, 0.05 ± 0.22; chromosome breaks, 0.02 ± 0.14.

  16. Are There Knots in Chromosomes?

    Directory of Open Access Journals (Sweden)

    Jonathan T. Siebert

    2017-08-01

    Full Text Available Recent developments have for the first time allowed the determination of three-dimensional structures of individual chromosomes and genomes in nuclei of single haploid mouse embryonic stem (ES cells based on Hi–C chromosome conformation contact data. Although these first structures have a relatively low resolution, they provide the first experimental data that can be used to study chromosome and intact genome folding. Here we further analyze these structures and provide the first evidence that G1 phase chromosomes are knotted, consistent with the fact that plots of contact probability vs sequence separation show a power law dependence that is intermediate between that of a fractal globule and an equilibrium structure.

  17. Flow cytogenetics and chromosome sorting.

    Science.gov (United States)

    Cram, L S

    1990-06-01

    This review of flow cytogenetics and chromosome sorting provides an overview of general information in the field and describes recent developments in more detail. From the early developments of chromosome analysis involving single parameter or one color analysis to the latest developments in slit scanning of single chromosomes in a flow stream, the field has progressed rapidly and most importantly has served as an important enabling technology for the human genome project. Technological innovations that advanced flow cytogenetics are described and referenced. Applications in basic cell biology, molecular biology, and clinical investigations are presented. The necessary characteristics for large number chromosome sorting are highlighted. References to recent review articles are provided as a starting point for locating individual references that provide more detail. Specific references are provided for recent developments.

  18. Direct kinetochore-spindle pole connections are not required for chromosome segregation.

    Science.gov (United States)

    Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G; McEwen, Bruce F; Chen, James K; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M; Khodjakov, Alexey

    2014-07-21

    Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes' kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells.

  19. No link between X chromosome inactivation pattern and simple goiter in females

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hansen, Pia Skov; Knudsen, Gun Peggy S

    2009-01-01

    healthy control twin individuals, and then performed a within-pair comparison of XCI in 48 twin pairs discordant for SG. METHODS: DNA was extracted from peripheral blood cells. XCI analysis was performed by predigestion of DNA using the methylation-sensitive enzyme Hpall, followed by polymerase chain...... by DNA fingerprinting. RESULTS: The frequency of skewed XCI in female twins with SG, DG, and NG was 11% (8/71), 13% (6/46), and 8% (2/25), respectively, which was not significantly different from the prevalences in the corresponding control populations, 14% (20/142, p = 0.56), 14% (13/92, p = 1...

  20. Algorithm for sorting chromosomal aberrations

    DEFF Research Database (Denmark)

    Vogel, Ida; Lund, Najaaraq; Rasmussen, Steen

    2018-01-01

    Prenatal diagnostic methods and screening procedures change rapidly in these years. Years ago only karyotyping was performed prenatally, and we monitored only Down syndrome(1) . Since then the diagnostic possibilities have increased to QF-PCR, FISH, MLPA and chromosomal microarray.......Prenatal diagnostic methods and screening procedures change rapidly in these years. Years ago only karyotyping was performed prenatally, and we monitored only Down syndrome(1) . Since then the diagnostic possibilities have increased to QF-PCR, FISH, MLPA and chromosomal microarray....

  1. Repressive but not activating epigenetic modifications are aberrant on the inactive X chromosome in live cloned cattle.

    Science.gov (United States)

    Geng-Sheng, Cao; Yu, Gao; Kun, Wang; Fang-Rong, Ding; Ning, Li

    2009-08-01

    X inactivation is the process of a chromosome-wide silencing of the majority of genes on the X chromosome during early mammalian development. This process may be aberrant in cloned animals. Here we show that repressive modifications, such as methylation of DNA, and the presence of methylated histones, H3K9me2 and H3K27me3, exhibit distinct aberrance on the inactive X chromosome in live clones. In contrast, H3K4me3, an active gene marker, is obviously missing from the inactive X chromosome in all cattle studied. This suggests that the disappearance of active histone modifications (H3K4me3) seems to be more important for X inactivation than deposition of marks associated with heterochromatin (DNA methylation, H3K27me3 and H3K9me2). It also implies that even apparently normal clones may have subtle abnormalities in repressive, but not activating epigenetic modifications on the inactive X when they survive to term. We also found that the histone H3 methylations were enriched and co-localized at q21-31 of the active X chromosome, which may be associated with an abundance of LINE1 repeat elements. © 2009 The Authors. Journal compilation © 2009 Japanese Society of Developmental Biologists.

  2. Tumor suppressor genes that escape from X-inactivation contribute to cancer sex bias

    Science.gov (United States)

    Dunford, Andrew; Weinstock, David M.; Savova, Virginia; Schumacher, Steven E.; Cleary, John P.; Yoda, Akinori; Sullivan, Timothy J.; Hess, Julian M.; Gimelbrant, Alexander A.; Beroukhim, Rameen; Lawrence, Michael S.; Getz, Gad; Lane, Andrew A.

    2016-01-01

    There is a striking and unexplained male predominance across many cancer types. A subset of X chromosome (chrX) genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative “Escape from X-Inactivation Tumor Suppressor” (EXITS) genes, we compared somatic alterations from >4100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) chrX genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) more frequently harbored loss-of-function mutations in males (based on false discovery rate <0.1), compared to zero of 18,055 autosomal and PAR genes (P<0.0001). Male-biased mutations in genes that escape X-inactivation were observed in combined analysis across many cancers and in several individual tumor types, suggesting a generalized phenomenon. We conclude that biallelic expression of EXITS genes in females explains a portion of the reduced cancer incidence compared to males across a variety of tumor types. PMID:27869828

  3. Diagnostic radiation and chromosome aberrations

    International Nuclear Information System (INIS)

    Patil, S.R.; Hecht, F.; Lubs, H.A.; Kimberling, W.; Brown, J.; Gerald, P.S.; Summitt, R.L.

    1977-01-01

    Some evidence is presented suggesting that diagnostic X-rays may be important in the origin of a new chromosomal abnormality other than Down syndrome. Chromosome analyses have been carried out on 4342 children, seven or eight years old. Maternal diagnostic irradiation in the year before conception and up to third lunar month of the index pregnancy was recorded, before the chromosome study began, together with a large amount of family and clinical data. Information on X-ray exposure was supplied by the mothers, s o radiation dosage could not be estimated. 21 children (including a pair of twins and a pair of siblings) born to 19 mothers had chromosomal aberrations. The mothers of six children with inherited translocations, rearrangements and XYY karyotypes were excluded, and 3 (23%) of the remaining 13 mothers had received abdominal and pelvic X-ray exposures. In the whole sample, however, only 6% of the mothers had diagnostic irradiation. Two of these mothers, aged sixteen and twenty, gave birth to a child each with de-novo autosomal translocations, and the third mother, aged thirty-two, had a child with a complex mosaicism involving one X chromosome. Although the sample size of the mothers with chromosomally abnormal children is small, the results are significant. (U.K.)

  4. Diagnostic radiation and chromosome aberrations

    Energy Technology Data Exchange (ETDEWEB)

    Patil, S R; Hecht, F [Dept. of Pediatrics, Child Development and Rehabilitation Center, Univ. of Oregon Health Sciences Center, Portland, Oregon (USA); Lubs, H A; Kimberling, W; Brown, J; Gerald, P S; Summitt, R L

    1977-01-15

    Some evidence is presented suggesting that diagnostic X-rays may be important in the origin of a new chromosomal abnormality other than Down syndrome. Chromosome analyses have been carried out on 4342 children, seven or eight years old. Maternal diagnostic irradiation in the year before conception and up to third lunar month of the index pregnancy was recorded, before the chromosome study began, together with a large amount of family and clinical data. Information on X-ray exposure was supplied by the mothers, so radiation dosage could not be estimated. 21 children (including a pair of twins and a pair of siblings) born to 19 mothers had chromosomal aberrations. The mothers of six children with inherited translocations, rearrangements and XYY karyotypes were excluded, and 3 (23%) of the remaining 13 mothers had received abdominal and pelvic X-ray exposures. In the whole sample, however, only 6% of the mothers had diagnostic irradiation. Two of these mothers, aged sixteen and twenty, gave birth to a child each with de-novo autosomal translocations, and the third mother, aged thirty-two, had a child with a complex mosaicism involving one X chromosome. Although the sample size of the mothers with chromosomally abnormal children is small, the results are significant.

  5. Designing of plant artificial chromosome (PAC) by using the Chlorella smallest chromosome as a model system.

    Science.gov (United States)

    Noutoshi, Y; Arai, R; Fujie, M; Yamada, T

    1997-01-01

    As a model for plant-type chromosomes, we have been characterizing molecular organization of the Chlorella vulgaris C-169 chromosome I. To identify chromosome structural elements including the centromeric region and replication origins, we constructed a chromosome I specific cosmid library and aligned each cosmid clones to generate contigs. So far, more than 80% of the entire chromosome I has been covered. A complete clonal physical reconstitution of chromosome I provides information on the structure and genomic organization of plant genome. We propose our strategy to construct an artificial chromosome by assembling the functional chromosome structural elements identified on Chrorella chromosome I.

  6. Numerically abnormal chromosome constitutions in humans

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  7. An X-linked homologue of the autosomal inprinted gene ZNF127 escapes X inactivation

    Energy Technology Data Exchange (ETDEWEB)

    Longstreet, M.; Nicholls, R.D.; Willard, H.F. [Case Western Reserve Univ., Cleveland, OH (United States)] [and others

    1994-09-01

    The ZNF127 gene has been shown to be subject to parental imprinting in both humans and the mouse and maps to within the Prader-Willi/Angelman Syndrome critical region on chromosome 15. We have cloned two X-linked related loci, one of which, ZNFXp is a transcribed gene while the other, ZNFXq, is an untranscribed pseudogene. ZNFXp is 83.6% identical to ZNFXq and 65.4% identical to ZNF127 over 1.4 kb of open reading frame they share in common, Like ZNF127, the predicted protein sequence of ZNFXp contains a C{sub 3}HC{sub 4} zinc finger domain and C{sub 3}H zinc finger-like motifs. Whereas ZNF127 has three C{sub 3}H motifs, ZNFXp has four. A strong CpG island is located within 1 kb 5{prime} of the predicted amino terminus of ZNFXp. Expression of ZNFXp has been detected from mouse/human somatic cell hybrids containing either an active (n=2) or an inactive (n=4) chromosome, and thus escapes X inactivation. Probes made from the 3{prime} UTR of ZNFXp detect a number of related loci in both human and murine DNA, none of which is the ZNF127 locus on chromosome 15. None of the detectable murine bands shows dosage differences between males and females as would be expected for X-linked loci. This raises the possibility that ZNFXp inserted into the human X chromosome after its divergence from a common ancestor with the murine X. We have mapped ZNFXp to Xp11.4 by Southern blotting and PCR of hybrid DNAs and by fluorescence in situ hybridization (FISH). ZNFXq maps within the X Inactivation Center (XIC) region on Xq13.2, approximately 300 kb distal to the XIST gene. We find it intriguing, and perhaps significant, that two members of this gene family are subject to epigenetic regulation -- one autosomal imprinting, and the other escape from X inactivation. These results could imply an evolutionary and mechanistic relationship between these two processes.

  8. Skewed X inactivation and survival: a 13-year follow-up study of elderly twins and singletons

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Thinggaard, Mikael; Christiansen, Lene

    2012-01-01

    In mammalian females, one of the two X chromosomes is inactivated in early embryonic life. Females are therefore mosaics for two cell populations, one with the maternal and one with the paternal X as the active X chromosome. A skewed X inactivation is a marked deviation from a 50:50 ratio...... mortality than the majority of women who had a more skewed DS (hazard ratio: 1.30; 95% CI: 1.04-1.64). The association between X inactivation and mortality was replicated in dizygotic twin pairs for which the co-twin with the lowest DS also had a statistically significant tendency to die first in the twin....... In populations of women past 55-60 years of age, an increased degree of skewing (DS) is found. Here the association between age-related skewing and mortality is analyzed in a 13-year follow-up study of 500 women from three cohorts (73-100 years of age at intake). Women with low DS had significantly higher...

  9. Control rod drive

    International Nuclear Information System (INIS)

    Okutani, Tetsuro.

    1988-01-01

    Purpose: To provide a simple and economical control rod drive using a control circuit requiring no pulse circuit. Constitution: Control rods in a BWR type reactor are driven by hydraulic pressure and inserted or withdrawn in the direction of applying the hydraulic pressure. The direction of the hydraulic pressure is controlled by a direction control valve. Since the driving for the control rod is extremely important in view of the operation, a self diagnosis function is disposed for rapid inspection of possible abnormality. In the present invention, two driving contacts are disposed each by one between the both ends of a solenoid valve of the direction control valve for driving the control rod and the driving power source, and diagnosis is conducted by alternately operating them. Therefore, since it is only necessary that the control circuit issues a driving instruction only to one of the two driving contacts, the pulse circuit is no more required. Further, since the control rod driving is conducted upon alignment of the two driving instructions, the reliability of the control rod drive can be improved. (Horiuchi, T.)

  10. Genetic characterization in symptomatic female DMD carriers: lack of relationship between X-inactivation, transcriptional DMD allele balancing and phenotype

    Directory of Open Access Journals (Sweden)

    Brioschi Simona

    2012-08-01

    Full Text Available Abstract Background Although Duchenne and Becker muscular dystrophies, X-linked recessive myopathies, predominantly affect males, a clinically significant proportion of females manifesting symptoms have also been reported. They represent an heterogeneous group characterized by variable degrees of muscle weakness and/or cardiac involvement. Though preferential inactivation of the normal X chromosome has long been considered the principal mechanism behind disease manifestation in these females, supporting evidence is controversial. Methods Eighteen females showing a mosaic pattern of dystrophin expression on muscle biopsy were recruited and classified as symptomatic (7 or asymptomatic (11, based on the presence or absence of muscle weakness. The causative DMD gene mutations were identified in all cases, and the X-inactivation pattern was assessed in muscle DNA. Transcriptional analysis in muscles was performed in all females, and relative quantification of wild-type and mutated transcripts was also performed in 9 carriers. Dystrophin protein was quantified by immunoblotting in 2 females. Results The study highlighted a lack of relationship between dystrophic phenotype and X-inactivation pattern in females; skewed X-inactivation was found in 2 out of 6 symptomatic carriers and in 5 out of 11 asymptomatic carriers. All females were characterized by biallelic transcription, but no association was found between X-inactivation pattern and allele transcriptional balancing. Either a prevalence of wild-type transcript or equal proportions of wild-type and mutated RNAs was observed in both symptomatic and asymptomatic females. Moreover, very similar levels of total and wild-type transcripts were identified in the two groups of carriers. Conclusions This is the first study deeply exploring the DMD transcriptional behaviour in a cohort of female carriers. Notably, no relationship between X-inactivation pattern and transcriptional behaviour of DMD gene was

  11. Transmission of chromosomal and instability via a chromosome irradiated with ionizing radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji; Tanabe, Masateru; Shiraishi, Kazunori; Oshimura, Mitsuo

    2010-01-01

    We examined the stability of the transferred chromosome in 5 and 12 microcell hybrids including unirradiated human chromosomes 6 and 8, respectively, and 6 and 19 microcell hybrids including 4 Gy-irradiated human chromosomes 6 and 8, respectively. The transferred chromosome was structurally stable in most microcell hybrids transferred with the unirradiated chromosomes 6 and 8. In contrast, the 4 Gy-irradiated human chromosomes were unstable in 3 out of 6 hybrids (50%) with chromosome 6 and 3 out of 19 hybrids (16%) with chromosome 8, showing multiple aberrations in high frequencies (35∼98%). To know the cause of delayed chromosomal instability, intrachromosomal rearrangements of the human chromosome is investigated by subtelomere FISH in 17 microcell hybrids transferred with chromosomes 6 and 8. We found frequent intrachromosomal in 7 microcell hybrids (41%). However, no clear correlation was observed between the intrachromosomal rearrangements and the induction of delayed chromosomal instability by ionizing radiation

  12. Potential Role of Meiosis Proteins in Melanoma Chromosomal Instability

    International Nuclear Information System (INIS)

    Lindsey, S. F.; Byrnes, D. M.; Eller, M. S.; Rosa, A. M.; Dabas, N.; Escandon, J.; Grichnik, J. M.; Grichnik, J. M.; Grichnik, J. M.; Grichnik, J. M.

    2013-01-01

    Melanomas demonstrate chromosomal instability (CIN). In fact, CIN can be used to differentiate melanoma from benign nevi. The exact molecular mechanisms that drive CIN in melanoma have yet to be fully elucidated. Cancer/testis antigens are a unique group of germ cell proteins that are found to be primarily expressed in melanoma as compared to benign nevi. The abnormal expression of these germ cell proteins, normally expected only in the testis and ovaries, in somatic cells may lead to interference with normal cellular pathways. Germ cell proteins that may be particularly critical in CIN are meiosis proteins. Here, we review pathways unique to meiosis with a focus on how the aberrant expression of meiosis proteins in normal mitotic cells "meiomitosis"could impact chromosomal instability in melanoma and other cancers.

  13. High Pressure Inactivation of HAV within Mussels

    Science.gov (United States)

    The potential of hepatitis A virus (HAV) to be inactivated within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) by high pressure processing was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contamina...

  14. Inactivation of prion infectivity by ionizing rays

    Energy Technology Data Exchange (ETDEWEB)

    Gominet, M. [Ionisos, ZI les Chatinieres, F01120 Dagneux (France); Vadrot, C.; Austruy, G. [Paris V University, Central Pharmacy of Hospitals, 4 avenue de l' Observatoire, F-75006, Paris (France); Darbord, J.C. [Paris V University, Central Pharmacy of Hospitals, 4 avenue de l' Observatoire, F-75006, Paris (France)], E-mail: darbord@pharmacie.univ-paris5.fr

    2007-11-15

    Inactivation of prion deposits on medical devices or prion contamination in pharmaceutical raw materials is considered as impossible by using gamma irradiation. Early, the guideline WHO/CDS/CSR/APH/2000 has described irradiation as an ineffective process. But, in 2003, S. Miekka et al. noted radiation inactivation of prions in a particular application to purify human albumin, shown by the physical denaturation of the infectious protein (PrP). The aim of our study was to determine the inactivation of prions with a scrapie model (strain C506M3) by irradiating standardised preparations. Results: Gamma irradiation was partially effective, showing a 4-5 log reduction on exposure to 50 kGy. A characteristic effect-dose curve was not observed (25, 50 and 100 kGy), only an increase in the incubation period of the murine disease (229 days with 25 kGy to 290 days with 100 kGy) compared with 170 days without irradiation. Since the inactivation was not a total one, the observed effect is significant. It is proposed that further work be undertaken with the model to investigate the application of gamma radiation known levels of prion contamination.

  15. Inactivation of prion infectivity by ionizing rays

    International Nuclear Information System (INIS)

    Gominet, M.; Vadrot, C.; Austruy, G.; Darbord, J.C.

    2007-01-01

    Inactivation of prion deposits on medical devices or prion contamination in pharmaceutical raw materials is considered as impossible by using gamma irradiation. Early, the guideline WHO/CDS/CSR/APH/2000 has described irradiation as an ineffective process. But, in 2003, S. Miekka et al. noted radiation inactivation of prions in a particular application to purify human albumin, shown by the physical denaturation of the infectious protein (PrP). The aim of our study was to determine the inactivation of prions with a scrapie model (strain C506M3) by irradiating standardised preparations. Results: Gamma irradiation was partially effective, showing a 4-5 log reduction on exposure to 50 kGy. A characteristic effect-dose curve was not observed (25, 50 and 100 kGy), only an increase in the incubation period of the murine disease (229 days with 25 kGy to 290 days with 100 kGy) compared with 170 days without irradiation. Since the inactivation was not a total one, the observed effect is significant. It is proposed that further work be undertaken with the model to investigate the application of gamma radiation known levels of prion contamination

  16. Pulsed electric field inactivation in a microreactor

    NARCIS (Netherlands)

    Fox, M.B.

    2006-01-01

    Pulsed electric fields (PEF) is a novel, non-thermal pasteurization method which uses short, high electric field pulses to inactivate microorganisms. The advantage of a pasteurization method like PEF compared to regular heat pasteurization is that the taste, flavour, texture and nutritional value

  17. Epigenetic inactivation of CHFR in human tumors.

    Science.gov (United States)

    Toyota, Minoru; Sasaki, Yasushi; Satoh, Ayumi; Ogi, Kazuhiro; Kikuchi, Takefumi; Suzuki, Hiromu; Mita, Hiroaki; Tanaka, Nobuyuki; Itoh, Fumio; Issa, Jean-Pierre J; Jair, Kam-Wing; Schuebel, Kornel E; Imai, Kohzoh; Tokino, Takashi

    2003-06-24

    Cell-cycle checkpoints controlling the orderly progression through mitosis are frequently disrupted in human cancers. One such checkpoint, entry into metaphase, is regulated by the CHFR gene encoding a protein possessing forkhead-associated and RING finger domains as well as ubiquitin-ligase activity. Although defects in this checkpoint have been described, the molecular basis and prevalence of CHFR inactivation in human tumors are still not fully understood. To address this question, we analyzed the pattern of CHFR expression in a number of human cancer cell lines and primary tumors. We found CpG methylation-dependent silencing of CHFR expression in 45% of cancer cell lines, 40% of primary colorectal cancers, 53% of colorectal adenomas, and 30% of primary head and neck cancers. Expression of CHFR was precisely correlated with both CpG methylation and deacetylation of histones H3 and H4 in the CpG-rich regulatory region. Moreover, CpG methylation and thus silencing of CHFR depended on the activities of two DNA methyltransferases, DNMT1 and DNMT3b, as their genetic inactivation restored CHFR expression. Finally, cells with CHFR methylation had an intrinsically high mitotic index when treated with microtubule inhibitor. This means that cells in which CHFR was epigenetically inactivated constitute loss-of-function alleles for mitotic checkpoint control. Taken together, these findings shed light on a pathway by which mitotic checkpoint is bypassed in cancer cells and suggest that inactivation of checkpoint genes is much more widespread than previously suspected.

  18. Retrospective dosimetry using chromosome painting

    International Nuclear Information System (INIS)

    Nasazzi, N.B.; Giorgio, M.D.; Taja, M.R.

    2000-01-01

    Chromosome aberration frequency measured in peripheral lymphocytes of persons exposed to ionizing radiation has been used since 1960s for dose assessment. Suspected overexposure is usually evaluated by the frequency of dicentrics and centric rings using an appropriate in vitro calibration curve. However, these chromosome aberrations are unstable with time after exposure and dose reconstruction may encounter uncertainties when the time between the exposure and the analysis is considerable or even unknown. It appears that translocations persist with time after exposure and may be used as an indication of acute past overexposures. Moreover, they appear to accumulate the cytogenetical information, which correlates with the dose received under fractionated, chronic or even occupational exposure conditions. Translocations may be detected using G-banding, which allows to score the total amount of radiation induced translocations but it is a time consuming method, or by Chromosome Painting, a method base on the Fluorescence in situ Hybridization (FISH) technique, painting only some chromosome pairs with specific whole chromosome probes and then extrapolating the observed translocation frequencies to the full genome. The latter method allows a faster aberration scoring than G-banding and appears to be the most promissory tool for biodosimetry, particularly when it is necessary to assess low doses and consequently to score a large number of metaphases, e.g. radiation workers exposed within dose limits. As with the unstable chromosome aberration, it is necessary an in vitro calibration curve based on the frequency of stable chromosome aberrations to assess doses. Our laboratory performed calibration curves for Co 60 γ-rays based on the frequencies of unstable (dicentrics and centric rings detected by conventional Giemsa staining) and stable chromosome aberrations (translocations and inversions, detected by G-banding). In order to minimize the interlaboratory variability, we

  19. Deletion of DXZ4 on the human inactive X chromosome alters higher-order genome architecture.

    Science.gov (United States)

    Darrow, Emily M; Huntley, Miriam H; Dudchenko, Olga; Stamenova, Elena K; Durand, Neva C; Sun, Zhuo; Huang, Su-Chen; Sanborn, Adrian L; Machol, Ido; Shamim, Muhammad; Seberg, Andrew P; Lander, Eric S; Chadwick, Brian P; Aiden, Erez Lieberman

    2016-08-02

    During interphase, the inactive X chromosome (Xi) is largely transcriptionally silent and adopts an unusual 3D configuration known as the "Barr body." Despite the importance of X chromosome inactivation, little is known about this 3D conformation. We recently showed that in humans the Xi chromosome exhibits three structural features, two of which are not shared by other chromosomes. First, like the chromosomes of many species, Xi forms compartments. Second, Xi is partitioned into two huge intervals, called "superdomains," such that pairs of loci in the same superdomain tend to colocalize. The boundary between the superdomains lies near DXZ4, a macrosatellite repeat whose Xi allele extensively binds the protein CCCTC-binding factor. Third, Xi exhibits extremely large loops, up to 77 megabases long, called "superloops." DXZ4 lies at the anchor of several superloops. Here, we combine 3D mapping, microscopy, and genome editing to study the structure of Xi, focusing on the role of DXZ4 We show that superloops and superdomains are conserved across eutherian mammals. By analyzing ligation events involving three or more loci, we demonstrate that DXZ4 and other superloop anchors tend to colocate simultaneously. Finally, we show that deleting DXZ4 on Xi leads to the disappearance of superdomains and superloops, changes in compartmentalization patterns, and changes in the distribution of chromatin marks. Thus, DXZ4 is essential for proper Xi packaging.

  20. Radiation-induced chromosomal instability

    International Nuclear Information System (INIS)

    Ritter, S.

    1999-01-01

    Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/μm) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

  1. Chromosome segregation in plant meiosis

    Directory of Open Access Journals (Sweden)

    Linda eZamariola

    2014-06-01

    Full Text Available 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.

  2. Radiation exposure and chromosome damage

    International Nuclear Information System (INIS)

    Lloyd, D.

    1979-01-01

    Chromosome damage is discussed as a means of biologically measuring radiation exposure to the body. Human lymphocytes are commonly used for this test since the extent of chromosome damage induced is related to the exposure dose. Several hundred lymphocytes are analysed in metaphase for chromosome damage, particularly dicentrics. The dose estimate is made by comparing the observed dicentric yield against calibration curves, previously produced by in vitro irradiation of blood samples to known doses of different types of radiation. This test is useful when there is doubt that the film badge has recorded a reasonable whole body dose and also when there is an absence of any physical data. A case of deliberate exposure is described where the chromosome damage test estimated an exposure of 152 rads. The life span of cell aberrations is also considered. Regular checks on radiotherapy patients and some accidental overdose cases have shown little reduction in the aberration levels over the first six weeks after which the damage disappears slowly with a half-life of about three years. In conclusion, chromosome studies have been shown to be of value in resolving practical problems in radiological protection. (U.K.)

  3. Using driving simulators to assess driving safety.

    Science.gov (United States)

    Boyle, Linda Ng; Lee, John D

    2010-05-01

    Changes in drivers, vehicles, and roadways pose substantial challenges to the transportation safety community. Crash records and naturalistic driving data are useful for examining the influence of past or existing technology on drivers, and the associations between risk factors and crashes. However, they are limited because causation cannot be established and technology not yet installed in production vehicles cannot be assessed. Driving simulators have become an increasingly widespread tool to understand evolving and novel technologies. The ability to manipulate independent variables in a randomized, controlled setting also provides the added benefit of identifying causal links. This paper introduces a special issue on simulator-based safety studies. The special issue comprises 25 papers that demonstrate the use of driving simulators to address pressing transportation safety problems and includes topics as diverse as neurological dysfunction, work zone design, and driver distraction. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  4. Cortical inactivation by cooling in small animals

    Directory of Open Access Journals (Sweden)

    Ben eCoomber

    2011-06-01

    Full Text Available Reversible inactivation of the cortex by surface cooling is a powerful method for studying the function of a particular area. Implanted cooling cryoloops have been used to study the role of individual cortical areas in auditory processing of awake-behaving cats. Cryoloops have also been used in rodents for reversible inactivation of the cortex, but recently there has been a concern that the cryoloop may also cool non-cortical structures either directly or via the perfusion of blood, cooled as it passed close to the cooling loop. In this study we have confirmed that the loop can inactivate most of the auditory cortex without causing a significant reduction in temperature of the auditory thalamus or other sub-cortical structures. We placed a cryoloop on the surface of the guinea pig cortex, cooled it to 2°C and measured thermal gradients across the neocortical surface. We found that the temperature dropped to 20-24°C among cells within a radius of about 2.5mm away from the loop. This temperature drop was sufficient to reduce activity of most cortical cells and led to the inactivation of almost the entire auditory region. When the temperature of thalamus, midbrain, and middle ear were measured directly during cortical cooling, there was a small drop in temperature (about 4°C but this was not sufficient to directly reduce neural activity. In an effort to visualise the extent of neural inactivation we measured the uptake of thallium ions following an intravenous injection. This confirmed that there was a large reduction of activity across much of the ipsilateral cortex and only a small reduction in subcortical structures.

  5. Superluminal warp drive

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, Pedro F. [Colina de los Chopos, Centro de Fisica ' Miguel A. Catalan' , Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)], E-mail: p.gonzalezdiaz@imaff.cfmac.csic.es

    2007-09-20

    In this Letter we consider a warp drive spacetime resulting from that suggested by Alcubierre when the spaceship can only travel faster than light. Restricting to the two dimensions that retains most of the physics, we derive the thermodynamic properties of the warp drive and show that the temperature of the spaceship rises up as its apparent velocity increases. We also find that the warp drive spacetime can be exhibited in a manifestly cosmological form.

  6. Two Y genes can replace the entire Y chromosome for assisted reproduction in the mouse.

    Science.gov (United States)

    Yamauchi, Yasuhiro; Riel, Jonathan M; Stoytcheva, Zoia; Ward, Monika A

    2014-01-03

    The Y chromosome is thought to be important for male reproduction. We have previously shown that, with the use of assisted reproduction, live offspring can be obtained from mice lacking the entire Y chromosome long arm. Here, we demonstrate that live mouse progeny can also be generated by using germ cells from males with the Y chromosome contribution limited to only two genes, the testis determinant factor Sry and the spermatogonial proliferation factor Eif2s3y. Sry is believed to function primarily in sex determination during fetal life. Eif2s3y may be the only Y chromosome gene required to drive mouse spermatogenesis, allowing formation of haploid germ cells that are functional in assisted reproduction. Our findings are relevant, but not directly translatable, to human male infertility cases.

  7. Medications and impaired driving.

    Science.gov (United States)

    Hetland, Amanda; Carr, David B

    2014-04-01

    To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded. Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed. Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

  8. Universal Drive Train Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This vehicle drive train research facility is capable of evaluating helicopter and ground vehicle power transmission technologies in a system level environment. The...

  9. The evolution of sex chromosomes in organisms with separate haploid sexes.

    Science.gov (United States)

    Immler, Simone; Otto, Sarah Perin

    2015-03-01

    The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings. © 2015 The Author(s).

  10. Direct kinetochore–spindle pole connections are not required for chromosome segregation

    Science.gov (United States)

    Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B.; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G.; McEwen, Bruce F.; Chen, James K.; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M.

    2014-01-01

    Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes′ kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells. PMID:25023516

  11. Histone H2AFX Links Meiotic Chromosome Asynapsis to Prophase I Oocyte Loss in Mammals.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Cloutier

    2015-10-01

    Full Text Available Chromosome abnormalities are common in the human population, causing germ cell loss at meiotic prophase I and infertility. The mechanisms driving this loss are unknown, but persistent meiotic DNA damage and asynapsis may be triggers. Here we investigate the contribution of these lesions to oocyte elimination in mice with chromosome abnormalities, e.g. Turner syndrome (XO and translocations. We show that asynapsed chromosomes trigger oocyte elimination at diplonema, which is linked to the presence of phosphorylated H2AFX (γH2AFX. We find that DNA double-strand break (DSB foci disappear on asynapsed chromosomes during pachynema, excluding persistent DNA damage as a likely cause, and demonstrating the existence in mammalian oocytes of a repair pathway for asynapsis-associated DNA DSBs. Importantly, deletion or point mutation of H2afx restores oocyte numbers in XO females to wild type (XX levels. Unexpectedly, we find that asynapsed supernumerary chromosomes do not elicit prophase I loss, despite being enriched for γH2AFX and other checkpoint proteins. These results suggest that oocyte loss cannot be explained simply by asynapsis checkpoint models, but is related to the gene content of asynapsed chromosomes. A similar mechanistic basis for oocyte loss may operate in humans with chromosome abnormalities.

  12. Histone H2AFX Links Meiotic Chromosome Asynapsis to Prophase I Oocyte Loss in Mammals

    Science.gov (United States)

    Cloutier, Jeffrey M.; Mahadevaiah, Shantha K.; ElInati, Elias; Nussenzweig, André; Tóth, Attila; Turner, James M. A.

    2015-01-01

    Chromosome abnormalities are common in the human population, causing germ cell loss at meiotic prophase I and infertility. The mechanisms driving this loss are unknown, but persistent meiotic DNA damage and asynapsis may be triggers. Here we investigate the contribution of these lesions to oocyte elimination in mice with chromosome abnormalities, e.g. Turner syndrome (XO) and translocations. We show that asynapsed chromosomes trigger oocyte elimination at diplonema, which is linked to the presence of phosphorylated H2AFX (γH2AFX). We find that DNA double-strand break (DSB) foci disappear on asynapsed chromosomes during pachynema, excluding persistent DNA damage as a likely cause, and demonstrating the existence in mammalian oocytes of a repair pathway for asynapsis-associated DNA DSBs. Importantly, deletion or point mutation of H2afx restores oocyte numbers in XO females to wild type (XX) levels. Unexpectedly, we find that asynapsed supernumerary chromosomes do not elicit prophase I loss, despite being enriched for γH2AFX and other checkpoint proteins. These results suggest that oocyte loss cannot be explained simply by asynapsis checkpoint models, but is related to the gene content of asynapsed chromosomes. A similar mechanistic basis for oocyte loss may operate in humans with chromosome abnormalities. PMID:26509888

  13. Translocations of chromosome end-segments and facultative heterochromatin promote meiotic ring formation in evening primroses.

    Science.gov (United States)

    Golczyk, Hieronim; Massouh, Amid; Greiner, Stephan

    2014-03-01

    Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories.

  14. Molecular mechanisms involved in the production of chromosomal aberrations. I

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Obe, G.

    1978-01-01

    Chinese hamster ovary cells (CHO) were X-irradiated in G2 stage of the cell cycle and immediately treated, in the presence of inactivated Sendai virus, with Neurospora endonuclease (E.C. 3.1.4.), an enzyme which is specific for cleaving single-stranded DNA. With this treatment, the frequencies of all types of chromosome aberrations increased when compared to X-irradiated controls. These results are interpreted as due to the conversion of some of the X-ray induced single-stranded DNA breaks into double-strand breaks by this enzyme. Similar enhancement due to this enzyme was found following treatment with methyl methanesulfonate (MMS) and bleomycin, but not following UV and mitomycin C. Addition of Micrococcus endonuclease and Neurospora endonuclease to the cells did not alter the frequencies of aberrations induced by UV. The introduction of enzymes with specific DNA-repair function offers possibilities to probe into the molecular events involved in the formation of structural chromosome aberrations induced by different classes of physical and chemical mutagens. (Auth.)

  15. Chromosomal rearrangements in Tourette syndrome

    DEFF Research Database (Denmark)

    Bertelsen, Birgitte; Debes, Nanette Mol; Hjermind, Lena E

    2013-01-01

    , and identification of susceptibility genes through linkage and association studies has been complicated due to inherent difficulties such as no clear mode of inheritance, genetic heterogeneity, and apparently incomplete penetrance. Positional cloning through mapping of disease-related chromosome rearrangements has...... been an efficient tool for the cloning of disease genes in several Mendelian disorders and in a number of complex disorders. Through cytogenetic investigation of 205 TS patients, we identified three possibly disease-associated chromosome rearrangements rendering this approach relevant in chasing TS...

  16. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.

    2009-01-01

    chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells. Overexpression of these "CIN-survival'' genes is associated with poor outcome in estrogen receptor......-positive breast cancer and occurs frequently in basal-like and Her2-positive cases. In diploid cells, but not in chromosomally unstable cells, paclitaxel causes repression of CIN-survival genes, followed by cell death. In the OV01 ovarian cancer clinical trial, a high level of CIN was associated with taxane...

  17. Inactivated probiotic Bacillus coagulans GBI-30 induces complex immune activating, anti-inflammatory, and regenerative markers in vitro

    OpenAIRE

    Jensen, Gitte S; Cash, Howard A; Farmer, Sean; Keller, David

    2017-01-01

    Gitte S Jensen,1 Howard A Cash,2 Sean Farmer,2 David Keller2 1NIS Labs, Esplanade, Klamath Falls, OR, USA, 2Ganeden Biotech Inc., Landerbrook Drive Suite, Mayfield Heights, OH, USA Objective: The aim of this study was to document the immune activating and anti-inflammatory effects of inactivated probiotic Bacillus coagulans GBI-30, 6086 (Staimune™) cells on human immune cells in vitro.Methods: In vitro cultures of human peripheral blood mononuclear cells (PBMC) from healthy blood do...

  18. Avian sex, sex chromosomes, and dosage compensation in the age of genomics.

    Science.gov (United States)

    Graves, Jennifer A Marshall

    2014-04-01

    Comparisons of the sex chromosome systems in birds and mammals are widening our view and deepening our understanding of vertebrate sex chromosome organization, function, and evolution. Birds have a very conserved ZW system of sex determination in which males have two copies of a large, gene-rich Z chromosome, and females have a single Z and a female-specific W chromosome. The avian ZW system is quite the reverse of the well-studied mammalian XY chromosome system, and evolved independently from different autosomal blocs. Despite the different gene content of mammal and bird sex chromosomes, there are many parallels. Genes on the bird Z and the mammal X have both undergone selection for male-advantage functions, and there has been amplification of male-advantage genes and accumulation of LINEs. The bird W and mammal Y have both undergone extensive degradation, but some birds retain early stages and some mammals terminal stages of the process, suggesting that the process is more advanced in mammals. Different sex-determining genes, DMRT1 and SRY, define the ZW and XY systems, but DMRT1 is involved in downstream events in mammals. Birds show strong cell autonomous specification of somatic sex differences in ZZ and ZW tissue, but there is growing evidence for direct X chromosome effects on sexual phenotype in mammals. Dosage compensation in birds appears to be phenotypically and molecularly quite different from X inactivation, being partial and gene-specific, but both systems use tools from the same molecular toolbox and there are some signs that galliform birds represent an early stage in the evolution of a coordinated system.

  19. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  20. Wrong-way driving.

    NARCIS (Netherlands)

    2006-01-01

    Wrong-way driving is a phenomenon that mainly happens on motorways. Although the number of wrong-way crashes is relatively limited, their consequences are much more severe than the consequences of other motorway injury crashes. The groups most often causing wrong-way driving accidents are young,

  1. Recognizing driving in haste

    NARCIS (Netherlands)

    Rendón-Vélez, E.

    2014-01-01

    One can often hear people discussing the reasons why a road accident has happened: “She had to pick up her kids in the school before four o’clock and she was driving in haste and careless”, “He was stressed, he wanted to reach the beginning of the football match, tried to drive faster and didn't

  2. Control rod drives

    International Nuclear Information System (INIS)

    Futatsugi, Masao.

    1980-01-01

    Purpose: To secure the reactor operation safety by the provision of a fluid pressure detecting section for control rod driving fluid and a control rod interlock at the midway of the flow pass for supplying driving fluid to the control rod drives. Constitution: Between a driving line and a direction control valve are provided a pressure detecting portion, an alarm generating device, and a control rod inhibition interlock. The driving fluid from a driving fluid source is discharged by way of a pump and a manual valve into the reactor in which the control rods and reactor fuels are contained. In addition, when the direction control valve is switched and the control rods are inserted and extracted by the control rod drives, the pressure in the driving line is always detected by the pressure detection section, whereby if abnormal pressure is resulted, the alarm generating device is actuated to warn the abnormality and the control rod inhibition interlock is actuated to lock the direction control valve thereby secure the safety operation of the reactor. (Seki, T.)

  3. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  4. Self-driving carsickness

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and

  5. Self-driving carsickness.

    NARCIS (Netherlands)

    Diels, C.; Bos, J.E.

    2016-01-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and

  6. Fundamentals of electrical drives

    CERN Document Server

    Veltman, André; De Doncker, Rik W

    2007-01-01

    Provides a comprehensive introduction to various aspects of electrical drive systems. This volume provides a presentation of dynamic generic models that cover all major electrical machine types and modulation/control components of a drive as well as dynamic and steady state analysis of transformers and electrical machines.

  7. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV......How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV...

  8. Mode of ATM-dependent suppression of chromosome translocation

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Motohiro, E-mail: motoyama@nagasaki-u.ac.jp [Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Suzuki, Keiji; Oka, Yasuyoshi; Suzuki, Masatoshi; Kondo, Hisayoshi; Yamashita, Shunichi [Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer We addressed how ATM suppresses frequency of chromosome translocation. Black-Right-Pointing-Pointer We found ATM/p53-dependent G1 checkpoint suppresses translocation frequency. Black-Right-Pointing-Pointer We found ATM and DNA-PKcs function in a common pathway to suppress translocation. -- Abstract: It is well documented that deficiency in ataxia telangiectasia mutated (ATM) protein leads to elevated frequency of chromosome translocation, however, it remains poorly understood how ATM suppresses translocation frequency. In the present study, we addressed the mechanism of ATM-dependent suppression of translocation frequency. To know frequency of translocation events in a whole genome at once, we performed centromere/telomere FISH and scored dicentric chromosomes, because dicentric and translocation occur with equal frequency and by identical mechanism. By centromere/telomere FISH analysis, we confirmed that chemical inhibition or RNAi-mediated knockdown of ATM causes 2 to 2.5-fold increase in dicentric frequency at first mitosis after 2 Gy of gamma-irradiation in G0/G1. The FISH analysis revealed that ATM/p53-dependent G1 checkpoint suppresses dicentric frequency, since RNAi-mediated knockdown of p53 elevated dicentric frequency by 1.5-fold. We found ATM also suppresses dicentric occurrence independently of its checkpoint role, as ATM inhibitor showed additional effect on dicentric frequency in the context of p53 depletion and Chk1/2 inactivation. Epistasis analysis using chemical inhibitors revealed that ATM kinase functions in the same pathway that requires kinase activity of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) to suppress dicentric frequency. From the results in the present study, we conclude that ATM minimizes translocation frequency through its commitment to G1 checkpoint and DNA double-strand break repair pathway that requires kinase activity of DNA-PKcs.

  9. Control rod drives

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1984-01-01

    Purpose: To enable to monitor the coupling state between a control rod and a control rod drive. Constitution: After the completion of a control rod withdrawal, a coolant pressure is applied to a control rod drive being adjusted so as to raise only the control rod drive and, in a case where the coupling between the control rod drive and the control rod is detached, the former is elevated till it contacts the control rod and then stopped. The actual stopping position is detected by an actual position detection circuit and compared with a predetermined position stored in a predetermined position detection circuit. If both of the positions are not aligned with each other, it is judged by a judging circuit that the control rod and the control rod drives are not combined. (Sekiya, K.)

  10. Genetics Home Reference: ring chromosome 20 syndrome

    Science.gov (United States)

    ... drugs. Prolonged seizure episodes known as non-convulsive status epilepticus also appear to be characteristic of ring chromosome ... K, Takahashi Y. Ring chromosome 20 and nonconvulsive status epilepticus. A new epileptic syndrome. Brain. 1997 Jun;120 ( ...

  11. Chromosomal disorders and male infertility

    Institute of Scientific and Technical Information of China (English)

    Gary L Harton; Helen G Tempest

    2012-01-01

    infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family.Despite this,the molecular and genetic factors underlying the cause of infertility remain largely undiscovered.Nevertheless,more and more genetic factors associated with infertility are being identified.This review will focus on our current understanding of the chromosomal basis of male infertility specifically:chromosomal aneuploidy,structural and numerical karyotype abnormalities and Y chromosomal microdeletions.Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans.Aneuploidy is predominantly maternal in origin,but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts.Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm.Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed,as well as the application of preimplantation genetic diagnosis (PGD) in such cases.Clinical recommendations where possible will be made,as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility.

  12. Chromosomal Abnormalities Associated With Omphalocele

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2007-03-01

    Full Text Available Fetuses with omphalocele have an increased risk for chromosomal abnormalities. The risk varies with maternal age, gestational age at diagnosis, association with umbilical cord cysts, complexity of associated anomalies, and the contents of omphalocele. There is considerable evidence that genetics contributes to the etiology of omphalocele. This article provides an overview of chromosomal abnormalities associated with omphalocele and a comprehensive review of associated full aneuploidy such as trisomy 18, trisomy 13, triploidy, trisomy 21, 45,X, 47,XXY, and 47,XXX, partial aneuploidy such as dup(3q, dup(11p, inv(11, dup(1q, del(1q, dup(4q, dup(5p, dup(6q, del(9p, dup(15q, dup(17q, Pallister-Killian syndrome with mosaic tetrasomy 12p and Miller-Dieker lissencephaly syndrome with deletion of 17p13.3, and uniparental disomy (UPD such as UPD 11 and UPD 14. Omphalocele is a prominent marker for chromosomal abnormalities. Perinatal identification of omphalocele should alert chromosomal abnormalities and familial unbalanced translocations, and prompt thorough cytogenetic investigations and genetic counseling.

  13. CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA

    Science.gov (United States)

    We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA ...

  14. Inactivation of biological substances by local heating

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Masahiro [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.

    1982-09-01

    Mechanism of inactivation of biological substances caused by local heating was investigated. The effect of hot-zone formation by local heating on reaction of radicals was previously evaluated. The thermal increase in a hot zone due to low energy LET x-rays had little effect on reactibility of the radicals, but, in a hot zone caused by high energy LET x-rays, formed radicals seemed immediately react to active biological molecules to inactivate them. Direct thermal effect on biological molecules was analysed. Thermal increase in a hot zone may induce degenaration of biological molecules which seems to occur in a short time judged from the extension of a hot zone and the duration of high temperature.

  15. Immunogenicity of UV-inactivated measles virus

    International Nuclear Information System (INIS)

    Zahorska, R.; Mazur, N.; Korbecki, M.

    1978-01-01

    By means of the antigen extinction limit test it was shown that a triple dose vaccination of guinea pigs with UV-inactivated measles virus gave better results, than a single dose vaccination which was proved by the very low immunogenicity index. For both vaccination schemes (single and triple) the immune response was only sligthly influenced by a change of dose from 10 5 to 10 6 HadU 50 /ml or by the addition of aluminum adjuvant. In the antigen extinction limit test the antibody levels were determined by two methods (HIT and NT) the results of which were statistically equivalent. The UV-inactivated measles virus was also found to induce hemolysis-inhibiting antibodies. (orig.) [de

  16. Inactivation of Anandamide Signaling: A Continuing Debate

    Directory of Open Access Journals (Sweden)

    Wael E. Houssen

    2010-10-01

    Full Text Available Since the first endocannabinoid anandamide was identified in 1992, extensive research has been conducted to characterize the elements of the tightly controlled endocannabinoid signaling system. While it was established that the activity of endocannabinoids are terminated by a two-step process that includes cellular uptake and degradation, there is still a continuing debate about the mechanistic role of these processes in inactivating anandamide signals.

  17. Photodynamic inactivation of antibiotic-resistant pathogens

    International Nuclear Information System (INIS)

    Paronyan, M.H.

    2015-01-01

    Nowadays methicillin-resistant strain Staphylococcus aureus (MRSA) is one of the most widespread multiresistant bacteria. Photodynamic inactivation (PDI) of microorganisms by photosensitizers (PS) may be an effective and alternative therapeutic option against antibiotic resistant bacteria. The effectiveness of new PS cationic porphyrin Zn-TBut4PyP was tested on two strains of S. aureus (MRSA and methicillin-sensitive S. aureus). It is shown that Zn-TBut4PyP has high photodynamic activity against both strains

  18. Epigenetic inactivation of CHFR in human tumors

    OpenAIRE

    Toyota, Minoru; Sasaki, Yasushi; Satoh, Ayumi; Ogi, Kazuhiro; Kikuchi, Takefumi; Suzuki, Hiromu; Mita, Hiroaki; Tanaka, Nobuyuki; Itoh, Fumio; Issa, Jean-Pierre J.; Jair, Kam-Wing; Schuebel, Kornel E.; Imai, Kohzoh; Tokino, Takashi

    2003-01-01

    Cell-cycle checkpoints controlling the orderly progression through mitosis are frequently disrupted in human cancers. One such checkpoint, entry into metaphase, is regulated by the CHFR gene encoding a protein possessing forkhead-associated and RING finger domains as well as ubiquitin–ligase activity. Although defects in this checkpoint have been described, the molecular basis and prevalence of CHFR inactivation in human tumors are still not fully understood. To address this question, w...

  19. Inactivation of human norovirus using chemical sanitizers.

    Science.gov (United States)

    Kingsley, David H; Vincent, Emily M; Meade, Gloria K; Watson, Clytrice L; Fan, Xuetong

    2014-02-03

    The porcine gastric mucin binding magnetic bead (PGM-MB) assay was used to evaluate the ability of chlorine, chlorine dioxide, peroxyacetic acid, hydrogen peroxide, and trisodium phosphate to inactivate human norovirus within 10% stool filtrate. One-minute free chlorine treatments at concentrations of 33 and 189 ppm reduced virus binding in the PGM-MB assay by 1.48 and 4.14 log₁₀, respectively, suggesting that chlorine is an efficient sanitizer for inactivation of human norovirus (HuNoV). Five minute treatments with 5% trisodium phosphate (pH~12) reduced HuNoV binding by 1.6 log₁₀, suggesting that TSP, or some other high pH buffer, could be used to treat food and food contact surfaces to reduce HuNoV. One minute treatments with 350 ppm chlorine dioxide dissolved in water did not reduce PGM-MB binding, suggesting that the sanitizer may not be suitable for HuNoV inactivation in liquid form. However a 60-min treatment with 350 ppm chlorine dioxide did reduce human norovirus by 2.8 log₁₀, indicating that chlorine dioxide had some, albeit limited, activity against HuNoV. Results also suggest that peroxyacetic acid has limited effectiveness against human norovirus, since 1-min treatments with up to 195 ppm reduced human norovirus binding by chlorine (sodium hypochlorite) as a HuNoV disinfectant wherever possible. Copyright © 2013. Published by Elsevier B.V.

  20. Radical inactivation of a biological sulphydryl molecule

    International Nuclear Information System (INIS)

    Lin, W.S.; Lal, M.; Gaucher, G.M.; Armstrong, D.A.

    1977-01-01

    Reactive species produced from the free radical-induced chain oxidation of low molecular weight sulphydryl-containing molecules in aerated solutions deactivate the sulphydryl-containing enzyme papain, forming both reparable mixed disulphides and non-reparable products. This inactivation is highly efficient for penicillamine and glutathione, but almost negligible with cysteine, which is a protector of papain for [cysteine] / [papain] >= 5 under all conditions used. In the case of glutathione, superoxide dismutase caused only a small reduction in the inactivation and peroxide yields were small, implying that the deactivating species are not .O 2 - but RSOO. radicals or products from them. For penicillamine, however, dimutase was highly effective and the peroxide yields were relatively large, demonstrating that .O 2 - or a radical with similar capabilities for forming H 2 O 2 and being deactivated by dismutase was involved. Although in the presence of dismutase penicillamine is a better protector of non-reparable papain inactivation than glutathione, it suffers from a deficiency in that the papain-penicillamine mixed disulphide, which is always formed, cannot be repaired by spontaneous reaction with RSH molecules. (author)

  1. Jarid2 Is Implicated in the Initial Xist-Induced Targeting of PRC2 to the Inactive X Chromosome

    DEFF Research Database (Denmark)

    da Rocha, Simão Teixeira; Boeva, Valentina; Escamilla-Del-Arenal, Martin

    2014-01-01

    complex, unlike at other parts of the genome, such as CG-rich regions, where Jarid2 and PRC2 binding are interdependent. Conversely, we show that Jarid2 loss prevents efficient PRC2 and H3K27me3 enrichment to Xist-coated chromatin. Jarid2 thus represents an important intermediate between PRC2 and Xist RNA......During X chromosome inactivation (XCI), the Polycomb Repressive Complex 2 (PRC2) is thought to participate in the early maintenance of the inactive state. Although Xist RNA is essential for the recruitment of PRC2 to the X chromosome, the precise mechanism remains unclear. Here, we demonstrate...... for the initial targeting of the PRC2 complex to the X chromosome during onset of XCI....

  2. The evolution of imprinting: chromosomal mapping of orthologues of mammalian imprinted domains in monotreme and marsupial mammals

    Directory of Open Access Journals (Sweden)

    Dunham Ian

    2007-09-01

    Full Text Available Abstract Background The evolution of genomic imprinting, the parental-origin specific expression of genes, is the subject of much debate. There are several theories to account for how the mechanism evolved including the hypothesis that it was driven by the evolution of X-inactivation, or that it arose from an ancestrally imprinted chromosome. Results Here we demonstrate that mammalian orthologues of imprinted genes are dispersed amongst autosomes in both monotreme and marsupial karyotypes. Conclusion These data, along with the similar distribution seen in birds, suggest that imprinted genes were not located on an ancestrally imprinted chromosome or associated with a sex chromosome. Our results suggest imprinting evolution was a stepwise, adaptive process, with each gene/cluster independently becoming imprinted as the need arose.

  3. Physical mapping of chromosome 8p22 markers and their homozygous deletion in a metastatic prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bova, G.S.; Pin, S.S.; Isaacs, W.B. [Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)]|[Brady Urological Institute, Baltimore, MD (United States)] [and others

    1996-07-01

    Numerous studies have implicated the short arm of chromosome 8 as the site of one or more tumor suppressor genes inactivated in carcinogenesis of the prostate, colon, lung, and liver. Previously, we identified a homozygous deletion on chromosome 8p22 in a metastatic prostate cancer. To map this homozygous deletion physically, long-range restriction mapping was performed using yeast artificial chromosomes (YACs) spanning approximately 2 Mb of chromosome band 8p22. Subcloned genomic DNA and cDNA probes isolated by hybrid capture from these YACs were mapped in relation to one another, reinforcing map integrity. Mapped single-copy probes from the region were then applied to DNA isolated from a metastatic prostate cancer containing a chromosome 8p22 homozygous deletion and indicated that its deletion spans 730-970 kb. Candidate genes PRLTS (PDGF-receptor {beta}-like tumor suppressor) and CTSB (cathepsin B) are located outside the region of homozygous deletion. Genethon marker D8S549 is located approximately at the center of this region of homozygous deletion. Two new microsatellite polymorphisms, D8S1991 and D8S1992, also located within the region of homozygous deletion on chromosome 8p22, are described. Physical mapping places cosmid CI8-2644 telomeric to MSR (macrophage scavenger receptor), the reverse of a previously published map, altering the interpretation of published deletion studies. This work should prove helpful in the identification of candidate tumor suppressor genes in this region. 47 refs., 5 figs., 1 tab.

  4. Molecular cloning and chromosome mapping of the human gene encoding protein phosphotyrosyl phosphatase 1B

    International Nuclear Information System (INIS)

    Brown-Shimer, S.; Johnson, K.A.; Bruskin, A.; Green, N.R.; Hill, D.E.; Lawrence, J.B.; Johnson, C.

    1990-01-01

    The inactivation of growth suppressor genes appears to play a major role in the malignant process. To assess whether protein phosphotyrosyl phosphatases function as growth suppressors, the authors have isolated a cDNA clone encoding human protein phosphotyrosyl phosphatase 1B for structural and functional characterization. The translation product deduced from the 1,305-nucleotide open reading frame predicts a protein containing 435 amino acids and having a molecular mass of 49,966 Da. The amino-terminal 321 amino acids deduced from the cDNA sequence are identical to the empirically determined sequence of protein phosphotyrosyl phosphatase 1B. A genomic clone has been isolated and used in an in situ hybridization to banded metaphase chromosomes to determine that the gene encoding protein phosphotyrosyl phosphatase 1B maps as a single-copy gene to the long arm of chromosome 20 in the region q13.1-q13.2

  5. Turbulent current drive mechanisms

    Science.gov (United States)

    McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

    2017-08-01

    Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm's law and hence provide an ideal means for driving deviations from neoclassical predictions.

  6. Fast wave current drive

    International Nuclear Information System (INIS)

    Goree, J.; Ono, M.; Colestock, P.; Horton, R.; McNeill, D.; Park, H.

    1985-07-01

    Fast wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfven wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into the plasma by fast wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast wave current drive is appropriate for higher plasma densities

  7. Identifying Method of Drunk Driving Based on Driving Behavior

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhao

    2011-05-01

    Full Text Available Drunk driving is one of the leading causes contributing to traffic crashes. There are numerous issues that need to be resolved with the current method of identifying drunk driving. Driving behavior, with the characteristic of real-time, was extensively researched to identify impaired driving behaviors. In this paper, the drives with BACs above 0.05% were defined as drunk driving state. A detailed comparison was made between normal driving and drunk driving. The experiment in driving simulator was designed to collect the driving performance data of the groups. According to the characteristics analysis for the effect of alcohol on driving performance, seven significant indicators were extracted and the drunk driving was identified by the Fisher Discriminant Method. The discriminant function demonstrated a high accuracy of classification. The optimal critical score to differentiate normal from drinking state was found to be 0. The evaluation result verifies the accuracy of classification method.

  8. Chromosomal Evolution in Lower Vertebrates: Sex Chromosomes in Neotropical Fishes

    Czech Academy of Sciences Publication Activity Database

    Cioffi, M. de B.; Yano, C. F.; Sember, Alexandr; Bertollo, L.A.C.

    2017-01-01

    Roč. 8, č. 10 (2017), č. článku 258. ISSN 2073-4425 R&D Projects: GA MŠk EF15_003/0000460 Institutional support: RVO:67985904 Keywords : alternative evolutionary models * simple and multiple sex chromosomes * independent and common origins Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Genetics and heredity (medical genetics to be 3) Impact factor: 3.600, year: 2016

  9. Microdissection and Chromosome Painting of the Alien Chromosome in an Addition Line of Wheat - Thinopyrum intermedium

    Science.gov (United States)

    Yin, Weibo; Zhang, Yingxin; Chen, Yuhong; Wang, Richard R.-C.; Zhang, Xiangqi; Han, Fangpu; Hu, Zanmin

    2013-01-01

    In this study, chromosome painting was developed and used to identify alien chromosomes in TAi-27, a wheat - Thinopyrum intermedium addition line, and the chromosomes of the three different genomes of Th. Intermedium. The smallest alien chromosome of TAi-27 was microdissected and its DNA amplified by DOP-PCR was used as a probe to hybridize with metaphase chromosomes of TAi-27 and Th . intermedium . Results showed that hybridization signals were observed in all regions of a pair of the smallest alien chromosomes and the pericentromeric area of another pair of alien chromosomes in TAi-27, indicating that the probe from microdissected chromosome is species specific. In Th . intermedium , 14 chromosomes had wide and strong hybridization signals distributed mainly on the pericentromere area and 9 chromosomes with narrow and weak signals on the pericentromere area. The remaining chromosomes displayed a very weak or no signal. Sequential FISH/GISH on Th . intermedium chromosomes using the DNAs of microdissected chromosome, Pseudoroegneria spicata (St genome) and pDbH12 (a Js genome specific probe) as the probes indicated that the microdissected chromosome belonged to the St genome, three genomes (Js, J and St) in Th . intermedium could be distinguished, in which there is no hybridization signal on J genome that is similar to the genome of Th . bessarabicum . Our results showed that the smallest alien chromosomes may represent a truncated chromosome and the repetitive sequence distribution might be similar in different chromosomes within the St genome. However, the repetitive sequence distributions are different within the Js genome, within a single chromosome, and among different genomes in Th . intermedium . Our results suggested that chromosome painting could be feasible in some plants and useful in detecting chromosome variation and repetitive sequence distribution in different genomes of polyploidy plants, which is helpful for understanding the evolution of different

  10. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate...... this incredibly big molecule and separate the two daughter chromosomes and how it makes sure that the daughter cells receives one copy each. The fully extended chromosome is two orders of magnitude larger than the cell in which it is contained. Hence the chromosome is heavily compacted in the cell...

  11. Linear step drive

    International Nuclear Information System (INIS)

    Haniger, L.; Elger, R.; Kocandrle, L.; Zdebor, J.

    1986-01-01

    A linear step drive is described developed in Czechoslovak-Soviet cooperation and intended for driving WWER-1000 control rods. The functional principle is explained of the motor and the mechanical and electrical parts of the drive, power control, and the indicator of position are described. The motor has latches situated in the reactor at a distance of 3 m from magnetic armatures, it has a low structural height above the reactor cover, which suggests its suitability for seismic localities. Its magnetic circuits use counterpoles; the mechanical shocks at the completion of each step are damped using special design features. The position indicator is of a special design and evaluates motor position within ±1% of total travel. A drive diagram and the flow chart of both the control electronics and the position indicator are presented. (author) 4 figs

  12. Fundamentals of electrical drives

    NARCIS (Netherlands)

    Veltman, A.; Pulle, D.W.J.; de Doncker, R.W.

    2016-01-01

    Comprehensive, user-friendly, color illustrated introductory text for electrical drive systems that simplifies the understanding of electrical machine principles Updated edition covers innovations in machine design, power semi-conductors, digital signal processors and simulation software Presents

  13. Science of driving.

    Science.gov (United States)

    2016-08-01

    The Science of Driving project focused on developing a collaborative relationship to develop curriculum units for middle school and high school students to engage them in exciting real-world scenarios. This effort involved faculty, staff, and student...

  14. Drugs and driving

    NARCIS (Netherlands)

    Walsh, J. Michael; De Gier, Johan J.; Christopherson, Asbjørg S.; Verstraete, Alain G.

    The authors present a global overview on the issue of drugs and driving covering four major areas: (1) Epidemiology and Prevalence-which reviews epidemiological research, summarizes available information, discusses the methodological shortcomings of extant studies, and makes recommendations for

  15. Instant Google Drive starter

    CERN Document Server

    Procopio, Mike

    2013-01-01

    This book is a Starter which teaches you how to use Google Drive practically. This book is perfect for people of all skill levels who want to enjoy the benefits of using Google Drive to safely store their files online and in the cloud. It's also great for anyone looking to learn more about cloud computing in general. Readers are expected to have an Internet connection and basic knowledge of using the internet.

  16. Control rod driving mechanism

    International Nuclear Information System (INIS)

    Ooshima, Yoshio.

    1983-01-01

    Purpose: To perform reliable scram operation, even if abnormality should occur in a system instructing scram operation in FBR type reactors. Constitution: An aluminum alloy member to be melt at a predetermined temperature (about 600sup(o)C) is disposed to a connection part between a control rod and a driving mechanism, whereby the control rod is detached from the driving mechanism and gravitationally fallen to the reactor core. (Ikeda, J.)

  17. Modulated Current Drive Measurements

    International Nuclear Information System (INIS)

    Petty, C.C.; Lohr, J.; Luce, T.C.; Prater, R.; Cox, W.A.; Forest, C.B.; Jayakumar, R.J.; Makowski, M.A.

    2005-01-01

    A new measurement approach is presented which directly determines the noninductive current profile from the periodic response of the motional Stark effect (MSE) signals to the slow modulation of the external current drive source. A Fourier transform of the poloidal magnetic flux diffusion equation is used to analyze the MSE data. An example of this measurement technique is shown using modulated electron cyclotron current drive (ECCD) discharges from the DIII-D tokamak

  18. Belt drive construction improvement

    Directory of Open Access Journals (Sweden)

    I.Yu. Khomenko

    2012-08-01

    Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

  19. Ultra high pressure homogenization (UHPH) inactivation of Bacillus amyloliquefaciens spores in phosphate buffered saline (PBS) and milk

    Science.gov (United States)

    Dong, Peng; Georget, Erika S.; Aganovic, Kemal; Heinz, Volker; Mathys, Alexander

    2015-01-01

    Ultra high pressure homogenization (UHPH) opens up new areas for dynamic high pressure assisted thermal sterilization of liquids. Bacillus amyloliquefaciens spores are resistant to high isostatic pressure and temperature and were suggested as potential surrogate for high pressure thermal sterilization validation. B. amyloliquefaciens spores suspended in PBS buffer (0.01 M, pH 7.0), low fat milk (1.5%, pH 6.7), and whole milk (3.5%, pH 6.7) at initial concentration of ~106 CFU/mL were subjected to UHPH treatments at 200, 300, and 350 MPa with an inlet temperature at ~80°C. Thermal inactivation kinetics of B. amyloliquefaciens spores in PBS and milk were assessed with thin wall glass capillaries and modeled using first-order and Weibull models. The residence time during UHPH treatments was estimated to determine the contribution of temperature to spore inactivation by UHPH. No sublethal injury was detected after UHPH treatments using sodium chloride as selective component in the nutrient agar medium. The inactivation profiles of spores in PBS buffer and milk were compared and fat provided no clear protective effect for spores against treatments. Treatment at 200 MPa with valve temperatures lower than 125°C caused no reduction of spores. A reduction of 3.5 log10CFU/mL of B. amyloliquefaciens spores was achieved by treatment at 350 MPa with a valve temperature higher than 150°C. The modeled thermal inactivation and observed inactivation during UHPH treatments suggest that temperature could be the main lethal effect driving inactivation. PMID:26236296

  20. Frequencies of chromosome aberration on radiation workers

    International Nuclear Information System (INIS)

    Yanti Lusiyanti; Zubaidah Alatas

    2016-01-01

    Radiation exposure of the body can cause damage to the genetic material in cells (cytogenetic) in the form of changes in the structure or chromosomal aberrations in peripheral blood lymphocytes. Chromosomal aberrations can be unstable as dicentric and ring chromosomes, and is stable as translocation. Dicentric chromosome is the gold standard biomarker due to radiation exposure, and chromosome translocation is a biomarker for retrospective biodosimetry. The aim of this studi is to conduct examination of chromosomal aberrations in the radiation worker to determine the potential damage of cell that may arise due to occupational radiation exposure. The examination have been carried out on blood samples from 55 radiation workers in the range of 5-30 year of service. Chromosome aberration frequency measurement starts with blood sampling, culturing, harvesting, slide preparations, and lymphocyte chromosome staining with Giemsa and painting with Fluorescence In Situ Hybridization (FISH) technique. The results showed that chromosomal translocations are not found in blood samples radiation workers and dicentric chromosomes found only on 2 blood samples of radiation workers with a frequency of 0.001/cell. The frequency of chromosomal aberrations in the blood cells such workers within normal limits and this means that the workers have been implemented a radiation safety aspects very well. (author)

  1. Self-driving carsickness.

    Science.gov (United States)

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  2. Dementia and driving.

    Science.gov (United States)

    O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K

    1992-04-01

    Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the driving practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to drive after the onset of dementia, and impaired driving ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop driving, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to driving ability. These findings suggest that many patients with dementia drive in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed.

  3. Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

    Science.gov (United States)

    Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

    2017-06-01

    The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × time reaction ) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, E a , induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Chromosomal instability induced by ionizing radiation

    International Nuclear Information System (INIS)

    Morgan, W.F.; Marder, B.A.; Day, J.P.

    1995-01-01

    There is accumulating evidence indicating genomic instability can manifest multiple generations after cellular exposure to DNA damaging agents. For instance, some cells surviving exposure to ionizing radiations show delayed reproductive cell death, delayed mutation and / or delayed chromosomal instability. Such instability, especially chromosome destabilization has been implicated in mutation, gene amplification, cellular transformation, and cell killing. To investigate chromosomal instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells. The relationship between delayed chromosomal destabilization and other endpoints of genomic instability, namely; delayed mutation and gene amplification will be discussed, as will the potential cytogenetic and molecular mechanisms contributing to delayed chromosomal instability

  5. Delayed chromosomal instability induced by DNA damage

    International Nuclear Information System (INIS)

    Morgan, W.F.; Marder, B.A.; Day, J.P.

    1994-01-01

    Cellular exposure to DNA damaging agents rapidly results in a dose dependent increase in chromosomal breakage and gross structural chromosomal rearrangements. Over recent years, evidence has been accumulating indicating genomic instability can manifest multiple generations after cellular exposure to physical and chemical DNA damaging agents. Genomic instability manifests in the progeny of surviving cells, and has been implicated in mutation, gene application, cellular transformation, and cell killing. To investigate chromosome instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells surviving X-irradiation many generations after exposure. At higher radiation doses, chromosomal instability was observed in a relatively high frequency of surviving clones and, in general, those clones showed delayed chromosome instability also showed reduced survival as measured by colony forming ability

  6. An oncogenic MYB feedback loop drives alternate cell fates in adenoid cystic carcinoma

    Science.gov (United States)

    Drier, Yotam; Cotton, Matthew J.; Williamson, Kaylyn E.; Gillespie, Shawn M.; Ryan, Russell J.H.; Kluk, Michael J.; Carey, Christopher D.; Rodig, Scott J.; Sholl, Lynette M; Afrogheh, Amir H.; Faquin, William C.; Queimado, Lurdes; Qi, Jun; Wick, Michael J.; El-Naggar, Adel K.; Bradner, James E.; Moskaluk, Christopher A.; Aster, Jon C.; Knoechel, Birgit; Bernstein, Bradley E.

    2016-01-01

    Translocation events are frequent in cancer and may create chimeric fusions or ‘regulatory rearrangements’ that drive oncogene overexpression. Here we identify super-enhancer translocations that drive overexpression of the oncogenic transcription factor MYB as a recurrent theme in adenoid cystic carcinoma (ACC). Whole-genome sequencing data and chromatin maps reveal distinct chromosomal rearrangements that juxtapose super-enhancers to the MYB locus. Chromosome conformation capture confirms that the translocated enhancers interact with the MYB promoter. Remarkably, MYB protein binds to the translocated enhancers, creating a positive feedback loop that sustains its expression. MYB also binds enhancers that drive different regulatory programs in alternate cell lineages in ACC, cooperating with TP63 in myoepithelial cells and a Notch program in luminal epithelial cells. Bromodomain inhibitors slow tumor growth in ACC primagraft models in vivo. Thus, our study identifies super-enhancer translocations that drive MYB expression and provides insight into downstream MYB functions in the alternate ACC lineages. PMID:26829750

  7. Chromosomes aberations and enviromental factors

    Directory of Open Access Journals (Sweden)

    Marković Srđan Z.

    2017-01-01

    Full Text Available Explanation the topic: Changes in genetic material can lead to aberrant cell in the direction of disorders of cellular regulation, malignant transformation, cell death, or if the adjustment was made at the level of the reproductive cells, to genetic changes in some of the consequent off spring. The topic position in scientific/professional public: Breaking of chromosomes can occur spontaneously or can be induced. Chromatid/chromosome breakings can be induced by different environmental factors: chemicals, biological clastogenic agents, accidentally or intentionally. Conclusions: The authors suggest: - making conditions for strong respect of environmental regulations; - to use higher plants for the early detection of environmental mutagens; - create and orderly update National radionuclide database.

  8. Sex, rebellion and decadence: the scandalous evolutionary history of the human Y chromosome.

    Science.gov (United States)

    Navarro-Costa, Paulo

    2012-12-01

    It can be argued that the Y chromosome brings some of the spirit of rock&roll to our genome. Equal parts degenerate and sex-driven, the Y has boldly rebelled against sexual recombination, one of the sacred pillars of evolution. In evolutionary terms this chromosome also seems to have adopted another of rock&roll's mottos: living fast. Yet, it appears to have refused to die young. In this manuscript the Y chromosome will be analyzed from the intersection between structural, evolutionary and functional biology. Such integrative approach will present the Y as a highly specialized product of a series of remarkable evolutionary processes. These led to the establishment of a sex-specific genomic niche that is maintained by a complex balance between selective pressure and the genetic diversity introduced by intrachromosomal recombination. Central to this equilibrium is the "polish or perish" dilemma faced by the male-specific Y genes: either they are polished by the acquisition of male-related functions or they perish via the accumulation of inactivating mutations. Thus, understanding to what extent the idiosyncrasies of Y recombination may impact this chromosome's role in sex determination and male germline functions should be regarded as essential for added clinical insight into several male infertility phenotypes. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. ATM promotes the obligate XY crossover and both crossover control and chromosome axis integrity on autosomes.

    Directory of Open Access Journals (Sweden)

    Marco Barchi

    2008-05-01

    Full Text Available During meiosis in most sexually reproducing organisms, recombination forms crossovers between homologous maternal and paternal chromosomes and thereby promotes proper chromosome segregation at the first meiotic division. The number and distribution of crossovers are tightly controlled, but the factors that contribute to this control are poorly understood in most organisms, including mammals. Here we provide evidence that the ATM kinase or protein is essential for proper crossover formation in mouse spermatocytes. ATM deficiency causes multiple phenotypes in humans and mice, including gonadal atrophy. Mouse Atm-/- spermatocytes undergo apoptosis at mid-prophase of meiosis I, but Atm(-/- meiotic phenotypes are partially rescued by Spo11 heterozygosity, such that ATM-deficient spermatocytes progress to meiotic metaphase I. Strikingly, Spo11+/-Atm-/- spermatocytes are defective in forming the obligate crossover on the sex chromosomes, even though the XY pair is usually incorporated in a sex body and is transcriptionally inactivated as in normal spermatocytes. The XY crossover defect correlates with the appearance of lagging chromosomes at metaphase I, which may trigger the extensive metaphase apoptosis that is observed in these cells. In addition, control of the number and distribution of crossovers on autosomes appears to be defective in the absence of ATM because there is an increase in the total number of MLH1 foci, which mark the sites of eventual crossover formation, and because interference between MLH1 foci is perturbed. The axes of autosomes exhibit structural defects that correlate with the positions of ongoing recombination. Together, these findings indicate that ATM plays a role in both crossover control and chromosome axis integrity and further suggests that ATM is important for coordinating these features of meiotic chromosome dynamics.

  10. Microdissection and chromosome painting of the alien chromosome in an addition line of wheat-Thinopyrum intermedium

    Science.gov (United States)

    The chromosome painting is an efficient tool for chromosome research. However, plant chromosome painting is relatively underdeveloped. In this study, chromosome painting was developed and used to identify alien chromosomes in TAi-27, a wheat-Thinopyrum intermedium addition line, and chromosomes of...

  11. Non-coding RNAs and epigenome: de novo DNA methylation, allelic exclusion and X-inactivation

    Directory of Open Access Journals (Sweden)

    V. A. Halytskiy

    2013-12-01

    Full Text Available Non-coding RNAs are widespread class of cell RNAs. They participate in many important processes in cells – signaling, posttranscriptional silencing, protein biosynthesis, splicing, maintenance of genome stability, telomere lengthening, X-inactivation. Nevertheless, activity of these RNAs is not restricted to posttranscriptional sphere, but cover also processes that change or maintain the epigenetic information. Non-coding RNAs can directly bind to the DNA targets and cause their repression through recruitment of DNA methyltransferases as well as chromatin modifying enzymes. Such events constitute molecular mechanism of the RNA-dependent DNA methylation. It is possible, that the RNA-DNA interaction is universal mechanism triggering DNA methylation de novo. Allelic exclusion can be also based on described mechanism. This phenomenon takes place, when non-coding RNA, which precursor is transcribed from one allele, triggers DNA methylation in all other alleles present in the cell. Note, that miRNA-mediated transcriptional silencing resembles allelic exclusion, because both miRNA gene and genes, which can be targeted by this miRNA, contain elements with the same sequences. It can be assumed that RNA-dependent DNA methylation and allelic exclusion originated with the purpose of counteracting the activity of mobile genetic elements. Probably, thinning and deregulation of the cellular non-coding RNA pattern allows reactivation of silent mobile genetic elements resulting in genome instability that leads to ageing and carcinogenesis. In the course of X-inactivation, DNA methylation and subsequent hete­rochromatinization of X chromosome can be triggered by direct hybridization of 5′-end of large non-coding RNA Xist with DNA targets in remote regions of the X chromosome.

  12. GSK-3 inhibitors induce chromosome instability

    Directory of Open Access Journals (Sweden)

    Staples Oliver D

    2007-08-01

    Full Text Available Abstract Background Several mechanisms operate during mitosis to ensure accurate chromosome segregation. However, during tumour evolution these mechanisms go awry resulting in chromosome instability. While several lines of evidence suggest that mutations in adenomatous polyposis coli (APC may promote chromosome instability, at least in colon cancer, the underlying mechanisms remain unclear. Here, we turn our attention to GSK-3 – a protein kinase, which in concert with APC, targets β-catenin for proteolysis – and ask whether GSK-3 is required for accurate chromosome segregation. Results To probe the role of GSK-3 in mitosis, we inhibited GSK-3 kinase activity in cells using a panel of small molecule inhibitors, including SB-415286, AR-A014418, 1-Azakenpaullone and CHIR99021. Analysis of synchronised HeLa cells shows that GSK-3 inhibitors do not prevent G1/S progression or cell division. They do, however, significantly delay mitotic exit, largely because inhibitor-treated cells have difficulty aligning all their chromosomes. Although bipolar spindles form and the majority of chromosomes biorient, one or more chromosomes often remain mono-oriented near the spindle poles. Despite a prolonged mitotic delay, anaphase frequently initiates without the last chromosome aligning, resulting in chromosome non-disjunction. To rule out the possibility of "off-target" effects, we also used RNA interference to selectively repress GSK-3β. Cells deficient for GSK-3β exhibit a similar chromosome alignment defect, with chromosomes clustered near the spindle poles. GSK-3β repression also results in cells accumulating micronuclei, a hallmark of chromosome missegregation. Conclusion Thus, not only do our observations indicate a role for GSK-3 in accurate chromosome segregation, but they also raise the possibility that, if used as therapeutic agents, GSK-3 inhibitors may induce unwanted side effects by inducing chromosome instability.

  13. Chromosome aberration assays in Allium

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.F.

    1982-01-01

    The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of Allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for their clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction, 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.

  14. Inter-chromosomal heterogeneity in the formation of radiation induced chromosomal aberrations

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Vermeulen, S.; Boei, J.J.W.A.

    1997-01-01

    It is generally assumed that radiation induced chromosomal lesions are distributed randomly and repaired randomly among the genome. Recent studies using fluorescent in situ hybridization (FISH) and chromosome specific DNA libraries indicate that some chromosomes are more sensitive for radiation induced aberration formation than others. Chromosome No. 4 in human and chromosome No. 8 in Chinese hamster have been found to involve more in exchange aberrations than others, when calculated on the basis of their DNA content. Painting with arm specific chromosome libraries indicate that the frequencies of radiation induced intra-chromosome exchanges (i.e., between the arms of a chromosome, such as centric rings and inversions) are far in excess than one would expect on the basis of the frequencies of observed inter-chromosomal exchanges. The possible factors leading to the observed heterogeneity will be discussed

  15. Control rod drive

    International Nuclear Information System (INIS)

    Hawke, B.C.

    1986-01-01

    A reactor core, one or more control rods, and a control rod drive are described for selectively inserting and withdrawing the one or more control rods into and from the reactor core, which consists of: a support structure secured beneath the reactor core; control rod positioning means supported by the support structure for movably supporting the control rod for movement between a lower position wherein the control rod is located substantially beneath the reactor core and an upper position wherein at least an upper portion of the control rod extends into the reactor core; transmission means; primary drive means connected with the control rod positioning means by the transmission means for positioning the control rod under normal operating conditions; emergency drive means for moving the control rod from the lower position to the upper position under emergency conditions, the emergency drive means including a weight movable between an upper and a lower position, means for movably supporting the weight, and means for transmitting gravitational force exerted on the weight to the control rod positioning means to move the control rod upwardly when the weight is pulled downwardly by gravity; the transmission means connecting the control rod positioning means with the emergency drive means so that the primary drive means effects movement of the weight and the control rod in opposite directions under normal conditions, thus providing counterbalancing to reduce the force required for upward movement of the control rod under normal conditions; and restraint means for restraining the fall of the weight under normal operating conditions and disengaging the primary drive means to release the weight under emergency conditions

  16. Chromosomal divergence and evolutionary inferences in Rhodniini based on the chromosomal location of ribosomal genes

    Directory of Open Access Journals (Sweden)

    Sebastian Pita

    2013-05-01

    Full Text Available In this study, we used fluorescence in situ hybridisation to determine the chromosomal location of 45S rDNA clusters in 10 species of the tribe Rhodniini (Hemiptera: Reduviidae: Triatominae. The results showed striking inter and intraspecific variability, with the location of the rDNA clusters restricted to sex chromosomes with two patterns: either on one (X chromosome or both sex chromosomes (X and Y chromosomes. This variation occurs within a genus that has an unchanging diploid chromosome number (2n = 22, including 20 autosomes and 2 sex chromosomes and a similar chromosome size and genomic DNA content, reflecting a genome dynamic not revealed by these chromosome traits. The rDNA variation in closely related species and the intraspecific polymorphism in Rhodnius ecuadoriensis suggested that the chromosomal position of rDNA clusters might be a useful marker to identify recently diverged species or populations. We discuss the ancestral position of ribosomal genes in the tribe Rhodniini and the possible mechanisms involved in the variation of the rDNA clusters, including the loss of rDNA loci on the Y chromosome, transposition and ectopic pairing. The last two processes involve chromosomal exchanges between both sex chromosomes, in contrast to the widely accepted idea that the achiasmatic sex chromosomes of Heteroptera do not interchange sequences.

  17. The B chromosome polymorphism of the grasshopper Eyprepocnemis plorans in North Africa. IV. Transmission of rare B chromosome variants.

    Science.gov (United States)

    Bakkali, M; Camacho, J P M

    2004-01-01

    In addition to the principal B chromosome (B(1)) in Moroccan populations of the grasshopper Eyprepocnemis plorans, nine B chromosome variants appeared at low frequency. The transmission of five of these rare B chromosome variants through females was analysed in three natural populations. Sixteen controlled crosses provided useful information on the transmission of B(M2), B(M6) and B(M7) in Smir, B(M3) and B(M6) in SO.DE.A. (Société de Développement Agricole lands near Ksar-el-Kebir city), and B(M2) and B(M10) in Mechra, all located in Morocco. Since six female parents carried two different B variants, a total of 22 progeny analyses could be studied. Intraindividual variation in B transmission rate (k(B)) was observed among the successive egg pods in 26.7 % of the females, but this variation did not show a consistent temporal pattern. Only the B(M2) and B(M6) variants in Smir showed net drive, although variation was high among crosses, especially for B(M2). These two variants are thus good candidates for future regenerations (the replacement of a neutralized B, B(1) in this case, by a new driving variant, B(M2) or B(M6)) in Smir, the northern population where the B polymorphism is presumably older. The analysis of all crosses performed in the three populations, including those reported previously for the analysis of B(1) transmission, showed that the largest variance in k(B) among crosses stands at the individual level, and not at population or type of B levels. The implications of these findings for the occurrence of possible regeneration processes in Moroccan populations are discussed. Copyright 2004 S. Karger AG, Basel

  18. Control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Hiroyasu.

    1979-01-01

    Purpose: To enable rapid control in a simple circuit by providing a motor control device having an electric capacity capable of simultaneously driving all of the control rods rapidly only in the inserting direction as well as a motor controlling device capable of fine control for the insertion and extraction at usual operation. Constitution: The control rod drives comprise a first motor control device capable of finely controlling the control rods both in inserting and extracting directions, a second motor control device capable of rapidly driving the control rods only in the inserting direction, and a first motor switching circuit and a second motor switching circuit switched by switches. Upon issue of a rapid insertion instruction for the control rods, the second motor switching circuit is closed by the switch and the second motor control circuit and driving motors are connected. Thus, each of the control rod driving motors is driven at a high speed in the inserting direction to rapidly insert all of the control rods. (Yoshino, Y.)

  19. Epilepsy and driving

    Directory of Open Access Journals (Sweden)

    Matej Mavrič

    2015-05-01

    Full Text Available Epilepsy poses a risk for all participants in road traffic; therefore people with epilepsy do not meet the criteria for an unlimited driving license. Their driving is affected not only by epileptic seizures causing impaired consciousness and involuntary movements, but also by antiepileptic drugs with their many unwanted affects. The experts have not yet agreed on whether people with epilepsy have an increased risk of experiencing a road traffic accident. However, recent data suggests that the overall risk is lower compared to other medical conditions. Scientific evidence forms the basis of legislation, which by limiting people with epilepsy, enables all participants in road traffic to drive in the safest possible environment. The legislation that governs epilepsy and driving in Slovenia has been recently thoroughly reformed and thus allows a less discriminatory management of people with epilepsy. Although people with epilepsy experience many issues in their daily life, including their personal relationships and employment, they often list the need for driving as a top concern in surveys. General physicians play an important role in managing the issues of people with epilepsy.

  20. Self-rated Driving and Driving Safety in Older Adults

    OpenAIRE

    Ross, Lesley A.; Dodson, Joan; Edwards, Jerri D.; Ackerman, Michelle L.; Ball, Karlene

    2012-01-01

    Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults’ self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving...

  1. Chromosome analysis of arsenic affected cattle

    Directory of Open Access Journals (Sweden)

    S. Shekhar

    2014-10-01

    Full Text Available Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

  2. Sexual dimorphism in white campion: complex control of carpel number is revealed by Y chromosome deletions

    International Nuclear Information System (INIS)

    Lardon, A.; Georgiev, S.; Aghmir, A.; Le Merrer, G.; Negrutiu, I.

    1999-01-01

    Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is under the control of two main regions on the Y chromosome. One such region, encoding the gynoecium-suppressing function (GSF), is responsible for the arrest of carpel initiation in male flowers. To generate chromosomal deletions, we used pollen irradiation in male plants to produce hermaphroditic mutants (bsx mutants) in which carpel development was restored. The mutants resulted from alterations in at least two GSF chromosomal regions, one autosomal and one located on the distal half of the (p)-arm of the Y chromosome. The two mutations affected carpel development independently, each mutation showing incomplete penetrance and variegation, albeit at significantly different levels. During successive meiotic generations, a progressive increase in penetrance and a reduction in variegation levels were observed and quantified at the level of the Y-linked GSF (GSF-Y). Possible mechanisms are proposed to explain the behavior of the bsx mutations: epigenetic regulation or/and second-site mutation of modifier genes. In addition, studies on the inheritance of the hermaphroditic trait showed that, unlike wild-type Y chromosomes, deleted Y chromosomes can be transmitted through both the male and the female lines. Altogether, these findings bring experimental support, on the one hand, to the existence on the Y chromosome of genic meiotic drive function(s) and, on the other hand, to models that consider that dioecy evolved through multiple mutation events. As such, the GSF is actually a system containing more than one locus and whose primary component is located on the Y chromosome

  3. Radiation inactivation of T7 phage

    International Nuclear Information System (INIS)

    Becker, D.; Redpath, J.L.; Grossweiner, L.I.

    1978-01-01

    The radiation inactivation of T7 phage by 25-MeV electron pulses has been measured in various media containing a wide concentration range of radical scavenging solutes and in the presence of protective and sensitizing agents. The dependence of sensitivity on pulse dose, from 1 mrad to 3.6 krad, is attributed to radical depletion via bimolecular processes. The survival data are analyzed by extending target theory to include diffusive reactions of primary and secondary radicals generated in the medium. It is concluded that OH radicals are the principal primary inactivating species and that secondary radicals from Br - , CNS - , uracil, glucose, ribose, sucrose, tyrosine, and histidine are lethal to some extent. In nutrient broth or 100 mM histidine, psoralen derivatives, Actinomycin D, and Mitomycin C are anoxic sensitizers. It is proposed that the psoralens promote the formation of non-strand break lesions as the sensitization mechanism. The target theory based on diffusional kinetics is applicable to other systems including single cells

  4. Instrument for Study of Microbial Thermal Inactivation

    Science.gov (United States)

    Dickerson, R. W.; Read, R. B.

    1968-01-01

    An instrument was designed for the study of thermal inactivation of microorganisms using heating times of less than 1 sec. The instrument operates on the principle of rapid automatic displacement of the microorganism to and from a saturated steam atmosphere, and the operating temperature range is 50 to 90 C. At a temperature of 70 C, thermometric lag (time required to respond to 63.2% of a step change) of the fluid sample containing microorganisms was 0.12 sec. Heating time required to heat the sample to within 0.1 C of the exposure temperature was less than 1 sec, permitting exposure periods as brief as 1 sec, provided the proper corrections are made for the lethal effect of heating. The instrument is most useful for heat exposure periods of less than 5 min, and, typically, more than 500 samples can be processed for microbial inactivation determinations within an 8-hr period. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 7 Fig. 8 PMID:4874466

  5. Influvac, a trivalent inactivated subunit influenza vaccine.

    Science.gov (United States)

    Zuccotti, Gian Vincenzo; Fabiano, Valentina

    2011-01-01

    Influenza represents a major sanitary and socio-economic burden and vaccination is universally considered the most effective strategy for preventing the disease and its complications. Traditional influenza vaccines have been on the market since the late 1940s, with million of doses administered annually worldwide, and demonstrated a substantial efficacy and safety. The trivalent inactivated subunit vaccine has been available for more than 25 years and has been studied in healthy children, adults and the elderly and in people affected by underlying chronic medical conditions. We describe vaccine technology focusing on subunit vaccine production procedures and mode of action and provide updated information on efficacy and safety available data. A review of efficacy and safety data in healthy subjects and in high risk populations from major sponsor- and investigator-driven studies. The vaccine showed a good immunogenicity and a favorable safety profile in all target groups. In the panorama of actually available influenza vaccines, trivalent inactivated subunit vaccine represents a well-established tool for preventing flu and the associated complications.

  6. Photodynamic inactivation of pathogens causing infectious keratitis

    Science.gov (United States)

    Simon, Carole; Wolf, G.; Walther, M.; Winkler, K.; Finke, M.; Hüttenberger, D.; Bischoff, Markus; Seitz, B.; Cullum, J.; Foth, H.-J.

    2014-03-01

    The increasing prevalence of antibiotic resistance requires new approaches also for the treatment of infectious keratitis. Photodynamic Inactivation (PDI) using the photosensitizer (PS) Chlorin e6 (Ce6) was investigated as an alternative to antibiotic treatment. An in-vitro cornea model was established using porcine eyes. The uptake of Ce6 by bacteria and the diffusion of the PS in the individual layers of corneal tissue were investigated by fluorescence. After removal of the cornea's epithelium Ce6-concentrations tested in liquid culture against different concentrations of Ce6 (1 - 512 μM) using 10 minutes irradiation (E = 18 J/cm2 ). This demonstrated that a complete inactivation of the pathogen strains were feasible whereby SA was slightly more susceptible than PA. 3909 mutants of the Keio collection of Escherichia coli (E.coli) were screened for potential resistance factors. The sensitive mutants can be grouped into three categories: transport mutants, mutants in lipopolysaccharide synthesis and mutants in the bacterial SOS-response. In conclusion PDI is seen as a promising therapy concept for infectious keratitis.

  7. IL26 gene inactivation in Equidae.

    Science.gov (United States)

    Shakhsi-Niaei, M; Drögemüller, M; Jagannathan, V; Gerber, V; Leeb, T

    2013-12-01

    Interleukin-26 (IL26) is a member of the IL10 cytokine family. The IL26 gene is located between two other well-known cytokines genes of this family encoding interferon-gamma (IFNG) and IL22 in an evolutionary conserved gene cluster. In contrast to humans and most other mammals, mice lack a functional Il26 gene. We analyzed the genome sequences of other vertebrates for the presence or absence of functional IL26 orthologs and found that the IL26 gene has also become inactivated in several equid species. We detected a one-base pair frameshift deletion in exon 2 of the IL26 gene in the domestic horse (Equus caballus), Przewalski horse (Equus przewalskii) and donkey (Equus asinus). The remnant IL26 gene in the horse is still transcribed and gives rise to at least five alternative transcripts. None of these transcripts share a conserved open reading frame with the human IL26 gene. A comparative analysis across diverse vertebrates revealed that the IL26 gene has also independently been inactivated in a few other mammals, including the African elephant and the European hedgehog. The IL26 gene thus appears to be highly variable, and the conserved open reading frame has been lost several times during mammalian evolution. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.

  8. Chromosomal abnormalities in human glioblastomas: gain in chromosome 7p correlating with loss in chromosome 10q.

    Science.gov (United States)

    Inda, María del Mar; Fan, Xing; Muñoz, Jorge; Perot, Christine; Fauvet, Didier; Danglot, Giselle; Palacio, Ana; Madero, Pilar; Zazpe, Idoya; Portillo, Eduardo; Tuñón, Teresa; Martínez-Peñuela, José María; Alfaro, Jorge; Eiras, José; Bernheim, Alain; Castresana, Javier S

    2003-01-01

    Various genomic alterations have been detected in glioblastoma. Chromosome 7p, with the epidermal growth factor receptor locus, together with chromosome 10q, with the phosphatase and tensin homologue deleted in chromosome 10 and deleted in malignant brain tumors-1 loci, and chromosome 9p, with the cyclin-dependent kinase inhibitor 2A locus, are among the most frequently damaged chromosomal regions in glioblastoma. In this study, we evaluated the genetic status of 32 glioblastomas by comparative genomic hybridization; the sensitivity of comparative genomic hybridization versus differential polymerase chain reaction to detect deletions at the phosphatase and tensin homologue deleted in chromosome 10, deleted in malignant brain tumors-1, and cyclin-dependent kinase inhibitor 2A loci and amplifications at the cyclin-dependent kinase 4 locus; the frequency of genetic lesions (gain or loss) at 16 different selected loci (including oncogenes, tumor-suppressor genes, and proliferation markers) mapping on 13 different chromosomes; and the possible existence of a statistical association between any pair of molecular markers studied, to subdivide the glioblastoma entity molecularly. Comparative genomic hybridization showed that the most frequent region of gain was chromosome 7p, whereas the most frequent losses occurred on chromosomes 10q and 13q. The only statistically significant association was found for 7p gain and 10q loss. Copyright 2002 Wiley-Liss, Inc.

  9. Persistence of chromosomal abnormalities additional to the Philadelphia chromosome after Philadelphia chromosome disappearance during imatinib therapy for chronic myeloid leukemia.

    Science.gov (United States)

    Zaccaria, Alfonso; Valenti, Anna Maria; Donti, Emilio; Gozzetti, Alessandro; Ronconi, Sonia; Spedicato, Francesco

    2007-04-01

    Five Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) patients with additional chromosome abnormalities at diagnosis have been followed during Imatinib therapy. In all, the Ph chromosome disappeared, while the 5 cases, additional abnormalities [dup(1); del(5), +8 (2 patients) and +14] persisted in the subsequent studies, performed over a period of 11 to 49 months, either alone or together with a karyotypically normal cell population. This finding is consistent with a secondary origin of the Ph chromosome in these patients. It is still to early to evaluate the possible prognostic value of these additional abnormalities.

  10. Gears and gear drives

    CERN Document Server

    Jelaska, Damir T

    2012-01-01

    Understanding how gears are formed and how they interact or 'mesh' with each other is essential when designing equipment that uses gears or gear trains. The way in which gear teeth are formed and how they mesh is determined by their geometry and kinematics, which is the topic of this book.  Gears and Gear Drives provides the reader with comprehensive coverage of gears and gear drives. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. Cylindric

  11. Toyota hybrid synergy drive

    Energy Technology Data Exchange (ETDEWEB)

    Gautschi, H.

    2008-07-01

    This presentation made at the Swiss 2008 research conference on traffic by Hannes Gautschi, director of service and training at the Toyota company in Switzerland, takes a look at Toyota's hybrid drive vehicles. The construction of the vehicles and their combined combustion engines and electric generators and drives is presented and the combined operation of these components is described. Braking and energy recovery are discussed. Figures on the performance, fuel consumption and CO{sub 2} output of the hybrid vehicles are compared with those of conventional vehicles.

  12. Chromosomes

    Science.gov (United States)

    ... Care Genomic Medicine Working Group New Horizons and Research Patient Management Policy and Ethics Issues Quick Links for Patient Care Education All About the Human Genome Project Fact Sheets Genetic Education Resources for ...

  13. Chromosome engineering: power tools for plant genetics.

    Science.gov (United States)

    Chan, Simon W L

    2010-12-01

    The term "chromosome engineering" describes technologies in which chromosomes are manipulated to change their mode of genetic inheritance. This review examines recent innovations in chromosome engineering that promise to greatly increase the efficiency of plant breeding. Haploid Arabidopsis thaliana have been produced by altering the kinetochore protein CENH3, yielding instant homozygous lines. Haploid production will facilitate reverse breeding, a method that downregulates recombination to ensure progeny contain intact parental chromosomes. Another chromosome engineering success is the conversion of meiosis into mitosis, which produces diploid gametes that are clones of the parent plant. This is a key step in apomixis (asexual reproduction through seeds) and could help to preserve hybrid vigor in the future. New homologous recombination methods in plants will potentiate many chromosome engineering applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Advances in plant chromosome genomics

    Czech Academy of Sciences Publication Activity Database

    Doležel, Jaroslav; Vrána, Jan; Cápal, Petr; Kubaláková, Marie; Burešová, Veronika; Šimková, Hana

    2014-01-01

    Roč. 32, č. 1 (2014), s. 122-136 ISSN 0734-9750 R&D Projects: GA ČR GAP501/10/1740; GA ČR GAP501/10/1778; GA ČR GBP501/12/G090; GA MŠk(CZ) LO1204 Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : BAC library * Chromosome sorting * Cytogenetics Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.015, year: 2014

  15. Giemsa C-banding of Barley Chromosomes. IV. Chromosomal Constitution of Autotetraploid Barley

    DEFF Research Database (Denmark)

    Linde-Laursen, Ib

    1984-01-01

    The progeny of an autotetraploid barley plant (C1) consisted of 45 tetraploids and 33 aneuploids. Giemsa C-banding was used to identify each of the chromosomes in 20 euploid and 31 aneuploid C2--seedlings, and in 11 C3--offspring of aneuploid C2--plants. The euploid C2--seedlings all had four...... homologues of each of the chromosomes. The aneuploid C2--seedlings were fairly equally distributed on hypo-and hyperploids, and on the seven chromosome groups. This suggests that a particular chromosome is lost or gained at random in gametes and embryos. The 11 C3--seedlings comprised seven true euploids......, one seedling with 2n=28 having an extra chromosome 6 and missing one chromosome 3, and three seedlings with 2n=29. The chromosomal composition of aneuploid C3--seedlings did not reflect that of their aneuploid C2--parents with respect to missing or extra chromosomes. Two hypohexaploid C2--seedlings...

  16. Genome organization and DNA methylation patterns of B chromosomes in the red fox and Chinese raccoon dogs.

    Science.gov (United States)

    Bugno-Poniewierska, Monika; Solek, Przemysław; Wronski, Mariusz; Potocki, Leszek; Jezewska-Witkowska, Grażyna; Wnuk, Maciej

    2014-12-01

    The molecular structure of B chromosomes (Bs) is relatively well studied. Previous research demonstrates that Bs of various species usually contain two types of repetitive DNA sequences, satellite DNA and ribosomal DNA, but Bs also contain genes encoding histone proteins and many others. However, many questions remain regarding the origin and function of these chromosomes. Here, we focused on the comparative cytogenetic characteristics of the red fox and Chinese raccoon dog B chromosomes with particular attention to the distribution of repetitive DNA sequences and their methylation status. We confirmed that the small Bs of the red fox show a typical fluorescent telomeric distal signal, whereas medium-sized Bs of the Chinese raccoon dog were characterized by clusters of telomeric sequences along their length. We also found different DNA methylation patterns for the B chromosomes of both species. Therefore, we concluded that DNA methylation may maintain the transcriptional inactivation of DNA sequences localized to B chromosomes and may prevent genetic unbalancing and several negative phenotypic effects. © 2014 The Authors.

  17. Scale down of the inactivated polio vaccine production process

    NARCIS (Netherlands)

    Thomassen, Y.E.; Oever, van 't R.; Vinke, C.M.; Spiekstra, A.; Wijffels, R.H.; Pol, van der L.A.; Bakker, W.A.M.

    2013-01-01

    The anticipated increase in the demand for inactivated polio vaccines resulting from the success in the polio eradication program requires an increase in production capacity and cost price reduction of the current inactivated polio vaccine production processes. Improvement of existing production

  18. Thermal inactivation kinetics of β-galactosidase during bread baking

    NARCIS (Netherlands)

    Zhang, L.; Chen, Xiao Dong; Boom, R.M.; Schutyser, M.A.I.

    2017-01-01

    In this study, β-galactosidase was utilized as a model enzyme to investigate the mechanism of enzyme inactivation during bread baking. Thermal inactivation of β-galactosidase was investigated in a wheat flour/water system at varying temperature-moisture content combinations, and in bread during

  19. Quantum chromodynamics as the sequential fragmenting with inactivation

    International Nuclear Information System (INIS)

    Botet, R.

    1996-01-01

    We investigate the relation between the modified leading log approximation of the perturbative QCD and the sequential binary fragmentation process. We will show that in the absence of inactivation, this process is equivalent to the QCD gluodynamics. The inactivation term yields a precise prescription of how to include the hadronization in the QCD equations. (authors)

  20. Quantum chromodynamics as the sequential fragmenting with inactivation

    Energy Technology Data Exchange (ETDEWEB)

    Botet, R. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique des Solides; Ploszajczak, M. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)

    1996-12-31

    We investigate the relation between the modified leading log approximation of the perturbative QCD and the sequential binary fragmentation process. We will show that in the absence of inactivation, this process is equivalent to the QCD gluodynamics. The inactivation term yields a precise prescription of how to include the hadronization in the QCD equations. (authors). 15 refs.

  1. Mutual inactivation of Notch receptors and ligands facilitates developmental patterning.

    Directory of Open Access Journals (Sweden)

    David Sprinzak

    2011-06-01

    Full Text Available Developmental patterning requires juxtacrine signaling in order to tightly coordinate the fates of neighboring cells. Recent work has shown that Notch and Delta, the canonical metazoan juxtacrine signaling receptor and ligand, mutually inactivate each other in the same cell. This cis-interaction generates mutually exclusive sending and receiving states in individual cells. It generally remains unclear, however, how this mutual inactivation and the resulting switching behavior can impact developmental patterning circuits. Here we address this question using mathematical modeling in the context of two canonical pattern formation processes: boundary formation and lateral inhibition. For boundary formation, in a model motivated by Drosophila wing vein patterning, we find that mutual inactivation allows sharp boundary formation across a broader range of parameters than models lacking mutual inactivation. This model with mutual inactivation also exhibits robustness to correlated gene expression perturbations. For lateral inhibition, we find that mutual inactivation speeds up patterning dynamics, relieves the need for cooperative regulatory interactions, and expands the range of parameter values that permit pattern formation, compared to canonical models. Furthermore, mutual inactivation enables a simple lateral inhibition circuit architecture which requires only a single downstream regulatory step. Both model systems show how mutual inactivation can facilitate robust fine-grained patterning processes that would be difficult to implement without it, by encoding a difference-promoting feedback within the signaling system itself. Together, these results provide a framework for analysis of more complex Notch-dependent developmental systems.

  2. The pulsed light inactivation of veterinary relevant microbial biofilms ...

    African Journals Online (AJOL)

    Results show that both Cryptosporidium and Giardia attach to biofilms in large numbers (100-1000 oo/cysts) in as little as 72 hours. Pulsed light successfully inactivated all test species (Listeria, Salmonella, Bacillus, Escherichia) in planktonic and biofilm form with an increase in inactivation for every increase in UV dose.

  3. Ebola Virus Inactivation by Detergents Is Annulled in Serum

    NARCIS (Netherlands)

    van Kampen, Jeroen J. A.; Tintu, Andrei; Russcher, Henk; Fraaij, Pieter L. A.; Reusken, Chantal B. E. M.; Rijken, Mikel; van Hellemond, Jaap J.; van Genderen, Perry J. J.; Koelewijn, Rob; de Jong, Menno D.; Haddock, Elaine; Fischer, Robert J.; Munster, Vincent J.; Koopmans, Marion P. G.

    2017-01-01

    Treatment of blood samples from hemorrhagic fever virus (HFV)-infected patients with 0.1% detergents has been recommended for virus inactivation and subsequent safe laboratory testing. However, data on virus inactivation by this procedure are lacking. Here we show the effect of this procedure on

  4. Method of inactivating reproducible forms of mycoplasma in biological preparations

    International Nuclear Information System (INIS)

    Veber, P.; Jurmanova, K.; Lesko, J.; Hana, L.; Veber, V.

    1978-01-01

    Inactivation of mycoplasms in biological materials was achieved using gamma radiation with a dose rate of 1x10 4 to 5x10 6 rads/h for 1 to 250 hours. The technique is advantageous for allowing the inactivation of the final form of products (tablets, vaccines, etc.). (J.P.)

  5. Comparing Expert and Novice Driving Behavior in a Driving Simulator

    Directory of Open Access Journals (Sweden)

    Hiran B. Ekanayake

    2014-02-01

    Full Text Available This paper presents a study focused on comparing driving behavior of expert and novice drivers in a mid-range driving simulator with the intention of evaluating the validity of driving simulators for driver training. For the investigation, measurements of performance, psychophysiological measurements, and self-reported user experience under different conditions of driving tracks and driving sessions were analyzed. We calculated correlations between quantitative and qualitative measures to enhance the reliability of the findings. The experiment was conducted involving 14 experienced drivers and 17 novice drivers. The results indicate that driving behaviors of expert and novice drivers differ from each other in several ways but it heavily depends on the characteristics of the task. Moreover, our belief is that the analytical framework proposed in this paper can be used as a tool for selecting appropriate driving tasks as well as for evaluating driving performance in driving simulators.

  6. Exceptional Complex Chromosomal Rearrangements in Three Generations

    Directory of Open Access Journals (Sweden)

    Hannie Kartapradja

    2015-01-01

    Full Text Available We report an exceptional complex chromosomal rearrangement (CCR found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband’s mother, which was confirmed using the whole chromosome painting (WCP FISH. High resolution whole genome microarray analysis of DNA from the proband’s mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother’s and grandmother’s CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations.

  7. Evaluation of Chromosomal Abnormalities and Common ...

    African Journals Online (AJOL)

    Evaluation of Chromosomal Abnormalities and Common Trombophilic Mutations in Cases with Recurrent Miscarriage. Ahmet Karatas, Recep Eroz, Mustafa Albayrak, Tulay Ozlu, Bulent Cakmak, Fatih Keskin ...

  8. Reflections and meditations upon complex chromosomal exchanges.

    Science.gov (United States)

    Savage, John R K

    2002-12-01

    The application of FISH chromosome painting techniques, especially the recent mFISH (and its equivalents) where all 23 human chromosome pairs can be distinguished, has demonstrated that many chromosome-type structural exchanges are much more complicated (involving more "break-rejoins" and arms) than has hitherto been assumed. It is clear that we have been greatly under-estimating the damage produced in chromatin by such agents as ionising radiation. This article gives a brief historical summary of observations leading up to this conclusion, and after outlining some of the problems surrounding the formation of complex chromosomes exchanges, speculates about possible solutions currently being proposed.

  9. Chromosomal aberrations in ore miners of Slovakia

    International Nuclear Information System (INIS)

    Beno, M.; Vladar, M.; Nikodemova, D.; Vicanova, M.; Durcik, M.

    1998-01-01

    A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

  10. Chromosome heteromorphisms in the Japanese, 3

    International Nuclear Information System (INIS)

    Sofuni, Toshio; Awa, A.A.

    1982-12-01

    The type and frequency of chromosome variants detected by the C-staining method were ascertained in 1,857 individuals residing in Hiroshima. The most frequent heteromorphic variant was the total inversion of the C-band in chromosome 9 found in 27 individuals (1.45%). The total inversion of the C-band in chromosome 1 was not seen in this sample, but the partial inversion of the C-band in chromosome 1 was found in 18 persons (0.97%). Partial inversion was also detected in the C-band in chromosome 9 in 22 individuals (1.18%). In chromosome 16, neither total nor partial inversion of the C-band was observed in the present study. The frequencies of chromosomes 1, 9, and 16 with a very large C-band were 0.70%, 0.22%, and 0.54%, respectively. Aside from these (1, 9, and 16) a very large C-band was found occasionally in chromosomes 4, 5, 6, 11, 12, 14, and 15, and an unusual insertion of the Y chromosome was observed. A total of 128 C-band variants (6.89%) was found in the 1,857 Hiroshima residents. (author)

  11. Driving skills after whiplash.

    Science.gov (United States)

    Gimse, R; Bjørgen, I A; Straume, A

    1997-09-01

    Previous studies have shown that some persons with longlasting problems after whiplash have changed eye movements. These changes have been related to disturbance of the posture control system. The question raised in the present study is whether such disturbances can influence daily life functions connected with balance, position and external movements, such as car driving. A group of 23 persons with disturbed eye movements due to whiplash injury, was tested in a driving simulator, together with a closely matched control group. The results revealed significant differences between the two groups with respect to response times to the traffic signs presented, identification of type of sign, as well as steering precision while the subjects' attention was directed to the process of identifying the signs. Alternative explanations such as driving experience, pain, medication or malingering are at least partly controlled for, but cannot completely be ruled out. A distorted posture control system leading to disturbance of eye movements seems to be the most likely primary causative factor, but these disturbances are most certainly complexly determined. Reduced attention capacity is considered to be a mediating secondary factor. Registration of eye movements may be a useful diagnostic tool to evaluate driving skill after whiplash.

  12. Gaze-controlled Driving

    DEFF Research Database (Denmark)

    Tall, Martin; Alapetite, Alexandre; San Agustin, Javier

    2009-01-01

    We investigate if the gaze (point of regard) can control a remote vehicle driving on a racing track. Five different input devices (on-screen buttons, mouse-pointing low-cost webcam eye tracker and two commercial eye tracking systems) provide heading and speed control on the scene view transmitted...

  13. Gas turbine drives

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Developments in gas turbine drives are reviewed, e.g., low weight per unit power and thrust-weight ratio, fast availability of the maximum speed, absolute resistance to cold and to droplet formation vibrationeless run, and low exhaust gas temperatures. Applications in aeronautic engineering (turbofan), power stations, marine propulsion systems, railways and road transportation vehicles are mentioned.

  14. Chaos in drive systems

    Directory of Open Access Journals (Sweden)

    Kratochvíl C.

    2007-10-01

    Full Text Available The purpose of this article is to provide an elementary introduction to the subject of chaos in the electromechanical drive systems. In this article, we explore chaotic solutions of maps and continuous time systems. These solutions are also bounded like equilibrium, periodic and quasiperiodic solutions.

  15. Electric Drive Study

    Science.gov (United States)

    1987-03-01

    compound promises to reduce weight of future permanent magnet motors by 20 to 30 percent; a similar reduction is expected in size (approximately 20...drive systems. The AC permanent magnet (brushless DC motor) is rapidly evolving and will replace most electrically excited machines. Permanent magnet motors using

  16. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Septon, Kendall K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-11

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  17. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  18. Driving While Intoxicated.

    Science.gov (United States)

    Brick, John

    Alcohol intoxication increases the risk of highway accidents, the relative risk of crash probability increasing as a function of blood alcohol content (BAC). Because alcohol use is more prevalent than use of other drugs, more is known about the relationship between alcohol use and driving. Most states presume a BAC of .10% to be evidence of drunk…

  19. Chromosomal instability can be induced by the formation of breakage-prone chromosome rearrangement junctions

    International Nuclear Information System (INIS)

    Allen, R.N.; Ritter, L.; Moore, S.R.; Grosovsky, A.J.

    2003-01-01

    Full text: Studies in our lab have led to the hypothesis that chromosomal rearrangements can generate novel breakage-prone sites, resulting in chromosomal instability acting predominantly in cis. For example, specific breakage of large blocks of centromeric region heterochromatin on chromosome 16q by treatment with 2,6-diaminopurine (DAP) is associated with repeated rearrangement of chromosome 16q during outgrowth of DAP-treated clones, thereby establishing a link between the initial site of damage and the occurrence of persistent chromosomal instability. Similarly, karyotypic analysis of gamma ray induced instability demonstrated that chromosomal rearrangements in sub-clones were significantly clustered near the site of previously identified chromosomal rearrangement junctions in unstable parental clones. This study investigates the hypothesis that integration of transfected sequences into host chromosomes could create breakage-prone junction regions and persistent genomic instability without exposure to DNA-damage agents. These junctions may mimic the unstable chromosomal rearrangements induced by DAP or radiation, and thus provide a test of the broader hypothesis that instability can to some extent be attributed to the formation of novel chromosomal breakage hot spots. These experiments were performed using human-hamster hybrid AL cells containing a single human chromosome 11, which was used to monitor instability in a chromosomal painting assay. AL cells were transfected with a 2.5 Kb fragment containing multiple copies of the 180 bp human alpha heterochromatic repeat, which resulted in chromosomal instability in 41% of the transfected clones. Parallel exposure to gamma-radiation resulted in a similar level of chromosomal instability, although control transfections with plasmid alone did not lead to karyotypic instability. Chromosomal instability induced by integration of alpha heterochromatic repeats was also frequently associated with delayed reproductive

  20. Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

    Science.gov (United States)

    Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

    2016-03-01

    Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

  1. Modelling and application of the inactivation of microorganism

    International Nuclear Information System (INIS)

    Oğuzhan, P.; Yangılar, F.

    2013-01-01

    Prevention of consuming contaminated food with toxic microorganisms causing infections and consideration of food protection and new microbial inactivation methods are obligatory situations. Food microbiology is mainly related with unwanted microorganisms spoiling foods during processing and transporting stages and causing diseases. Determination of pathogen microorganisms is important for human health to define and prevent dangers and elongate shelf life. Inactivation of pathogen microorganisms can provide food security and reduce nutrient losses. Microbial inactivation which is using methods of food protection such as food safety and fresh. With this aim, various methods are used such as classical thermal processes (pasteurisation, sterilisation), pressured electrical field (PEF), ionised radiation, high pressure, ultrasonic waves and plasma sterilisation. Microbial inactivation modelling is a secure and effective method in food production. A new microbiological application can give useful results for risk assessment in food, inactivation of microorganisms and improvement of shelf life. Application and control methods should be developed and supported by scientific research and industrial applications

  2. Chromosomal replicons of higher plants

    International Nuclear Information System (INIS)

    Van't Hof, J.

    1987-01-01

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs

  3. Increased chromosome radiosensitivity during pregnancy

    International Nuclear Information System (INIS)

    Ricoul, Michelle; Sabatier, Laure; Dutrillaux, Bernard

    1997-01-01

    It was necessary to consider the risks of exposure of pregnant women, not only in relation to the child, but also in relation to their own hypersensitivity. We have demonstrated that pregnancy increases radiosensitivity of chromosome in the mouse at the end of gestation. This is of importance since it may have implications on radioprotection of pregnant women and give experimental guidelines to the problems of hypersensitivity to drugs and cancer aggravation during pregnancy. Blood obtained from women at various times of pregnancy was exposed to ionizing radiations. By comparison to non-pregnant women, an increase in chromosome breakage was observed in metaphases from lymphocytes, after short-term culture in the presence of the serum of the same donor. Immediately after delivery, this increase in radiosensitivity disappeared. In a prospective study, serial analyses showed a very strong correlation between the amount of pregnancy hormones, progesterone in particular, and the increase in radiosensitivity. Pregnant women may have an increased sensitivity to ionizing radiation during the second half of their pregnancy. This study provides the first evidence in human that radiosensitivity may vary in relation to physiological conditions

  4. Exchange of core chromosomes and horizontal transfer of lineage-specific chromosomes in Fusarium oxysporum

    NARCIS (Netherlands)

    Vlaardingerbroek, I.; Beerens, B.; Rose, L.; Fokkens, L.; Cornelissen, B.J.C.; Rep, M.

    2016-01-01

    Horizontal transfer of supernumerary or lineage-specific (LS) chromosomes has been described in a number of plant pathogenic filamentous fungi. So far it was not known whether transfer is restricted to chromosomes of certain size or properties, or whether 'core' chromosomes can also undergo

  5. Stabilization of chromosomes by DNA intercalators for flow karyotyping and identification by banding of isolated chromosomes

    NARCIS (Netherlands)

    Aten, J. A.; Buys, C. H.; van der Veen, A. Y.; Mesa, J. R.; Yu, L. C.; Gray, J. W.; Osinga, J.; Stap, J.

    1987-01-01

    A number of structurally unrelated DNA intercalators have been studied as stabilizers of mitotic chromosomes during isolation from rodent and human metaphase cells. Seven out of the nine intercalators tested were found to be useful as chromosome stabilizing agents. Chromosome suspensions prepared in

  6. Inactivation of Coxiella burnetti by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Scott, G.H.; McCaul, T.F.; Williams, J.C.

    1989-01-01

    The gamma radiation inactivation kinetics for Coxiella burnetii at - 79 C were exponential. The radiation dose needed to reduce the number of infective C. burnetii by 90% varied from 0-64 to 1.2 kGy depending on the phase of hte micro-organism, purity of the culture and composition of suspending menstruum. The viability of preparations containing C. burnetti was completely abolished by 10 kGy without diminishing antigenicity or ability to elicit a protective immune response in vaccinated mice. Immunocytochemical examinations using monoclonal antibodies and electron microscopy demonstrated that radiation doses of 20 kGy did not alter cell-wall morphology or cell-surface antigenic epitopes.

  7. Inactivation of Coxiella burnetii by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Scott, G.H.; McCaul, T.F. (Army Medical Research Inst. of Infectious Diseases, Fort Detrick, Frederick, MD (USA)); Williams, J.C. (National Inst. of Allergy and Infectious Diseases, Bethesda, MD (USA))

    1989-12-01

    The gamma radiation inactivation kinetics for Coxiella burnetii at - 79{sup 0}C were exponential. The radiation dose needed to reduce the number of infective C. burnetii by 90% varied from 0.64 to 1.2 kGy depending on the phase of the micro-organism, purity of the culture and composition of suspending menstruum. The viability of preparations containing 10{sup 11} C. burnetii ml{sup -1} was completely abolished by 10 kGy without diminishing antigenicity or ability to elicit a protective immune response in vaccinated mice. Immunocytochemical examinations using monoclonal antibodies and electron microscopy demonstrated that radiation doses of 20 kGy did not alter cell-wall morphology or cell-surface antigenic epitopes. (author).

  8. Inactivation of mitochondrial ATPase by ultraviolet light

    International Nuclear Information System (INIS)

    Chavez, E.; Cuellar, A.

    1984-01-01

    The present work describes experiments that show that far-ultraviolet irradiation induce the inhibition of ATPase activity in both membrane-bound and soluble F1. It was also found that ultraviolet light promotes the release of tightly bound adenine nucleotides from F1-ATPase. Experiments carried out with submitochondrial particles indicate that succinate partially protects against these effects of ultraviolet light. Titration of sulfhydryl groups in both irradiated submitochondrial particles and soluble F1-ATPase indicates that a conformational change induced by photochemical modifications of amino acid residues appears involved in the inactivation of the enzyme. Finally, experiments are described which show that the tyrosine residue located in the active site of F1-ATPase is modified by ultraviolet irradiation

  9. Inactivation of Coxiella burnetii by gamma irradiation

    International Nuclear Information System (INIS)

    Scott, G.H.; McCaul, T.F.; Williams, J.C.

    1989-01-01

    The gamma radiation inactivation kinetics for Coxiella burnetii at - 79 0 C were exponential. The radiation dose needed to reduce the number of infective C. burnetii by 90% varied from 0.64 to 1.2 kGy depending on the phase of the micro-organism, purity of the culture and composition of suspending menstruum. The viability of preparations containing 10 11 C. burnetii ml -1 was completely abolished by 10 kGy without diminishing antigenicity or ability to elicit a protective immune response in vaccinated mice. Immunocytochemical examinations using monoclonal antibodies and electron microscopy demonstrated that radiation doses of 20 kGy did not alter cell-wall morphology or cell-surface antigenic epitopes. (author)

  10. Esterase resistant to inactivation by heavy metals

    KAUST Repository

    El, Dorry Hamza

    2014-09-25

    EstATII is an esterase that a halotolerant, thermophilic and resistant to a spectrum of heavy metals including toxic concentration of metals. It was isolated from the lowest convective layer of the Atlantis II Red Sea brine pool. The Atlantis II brine pool is an extreme environment that possesses multiple harsh conditions such as; high temperature, salinity, pH and high concentration of metals, including toxic heavy metals. A fosmid metagenomic library using DNA isolated from the lowest convective layer this pool was used to identify EstATII. Polynucleotides encoding EstATII and similar esterases are disclosed and can be used to make EstATII. EstATII or compositions or apparatuses that contain it may be used in various processes employing lipases/esterases especially when these processes are performed under harsh conditions that inactivate other kinds of lipases or esterases.

  11. Polyphenol Oxidase Enzyme and Inactivation Methods

    Directory of Open Access Journals (Sweden)

    Leman Yılmaz

    2018-03-01

    Full Text Available Polyphenol oxidase enzyme is found in vegetables and fruits, as well as in some animal organs and microorganisms. Polyphenol oxidase enzyme responsible for enzymatic browning is a group of copper proteins that catalyses the oxidation of phenolic compounds to quinones, which produce brown pigments, commonly found in fruits and vegetables. During the industrial preparation of fruits and vegetables, results of catalytic effect of polyphenol oxidase causes enzymatic browning. Enzymatic browning impairs the appearance of products containing phenolic compounds along with undesirable colour, odor and taste formation and significant loss of nutritional value of the products. This affects the acceptability of the products by the consumers and causes economic losses. In this review, some characteristics of polyphenol oxidase enzyme in different fruits and vegetables have been reviewed and information about chemical antibrowning agents, thermal applications, irradiation applications and alternative methods such as high pressure processing, pulse electric field, supercritical carbon dioxide and ultrasound applications to inactivate this enzyme has been presented.

  12. UV inactivation of pathogenic and indicator microorganisms

    International Nuclear Information System (INIS)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-01-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts

  13. UV inactivation of pathogenic and indicator microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-06-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.

  14. Rod drive and latching mechanism

    International Nuclear Information System (INIS)

    Veronesi, L.; Sherwood, D.G.

    1982-01-01

    Hydraulic drive and latching mechanisms for driving reactivity control mechanisms in nuclear reactors are described. Preferably, the pressurized reactor coolant is utilized to raise the drive rod into contact with and to pivot the latching mechanism so as to allow the drive rod to pass the latching mechanism. The pressure in the housing may then be equalized which allows the drive rod to move downwardly into contact with the latching mechanism but to hold the shaft in a raised position with respect to the reactor core. Once again, the reactor coolant pressure may be utilized to raise the drive rod and thus pivot the latching mechanism so that the drive rod passes above the latching mechanism. Again, the mechanism pressure can be equalized which allows the drive rod to fall and pass by the latching mechanism so that the drive rod approaches the reactor core. (author)

  15. Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses[W][OPEN

    Science.gov (United States)

    Golczyk, Hieronim; Massouh, Amid; Greiner, Stephan

    2014-01-01

    Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories. PMID:24681616

  16. Electrical drives for direct drive renewable energy systems

    CERN Document Server

    Mueller, Markus

    2013-01-01

    Wind turbine gearboxes present major reliability issues, leading to great interest in the current development of gearless direct-drive wind energy systems. Offering high reliability, high efficiency and low maintenance, developments in these direct-drive systems point the way to the next generation of wind power, and Electrical drives for direct drive renewable energy systems is an authoritative guide to their design, development and operation. Part one outlines electrical drive technology, beginning with an overview of electrical generators for direct drive systems. Principles of electrical design for permanent magnet generators are discussed, followed by electrical, thermal and structural generator design and systems integration. A review of power electronic converter technology and power electronic converter systems for direct drive renewable energy applications is then conducted. Part two then focuses on wind and marine applications, beginning with a commercial overview of wind turbine drive systems and a...

  17. Inactivating Mutation screening of Exon 6 and Exon 10E of FSHR gene in women with Polycystic Ovarian Syndrome in Vellore population

    Science.gov (United States)

    Sekar, Nishu; Sapre, Madhura; Kale, Vaikhari; Prabhu, Yogamaya D.; Renu, Kaviyarasi; Ramgir, Shalaka S.; Abilash, V. G.

    2017-11-01

    Polycystic Ovarian syndrome (PCOS) is a major cause of infertility in females of reproducing age and is typified by oligo-anovulation, hyperandrogenism, hirsutism and polycystic ovaries. FSHR gene located on chromosome 2 p21 is responsible for the normal follicular development and any deletion or mutation in the gene affects the interaction of FSH with its receptor. Thus, it becomes the candidate gene for PCOS study. Inactivating mutation in FSHR gene limits the receptor’s function by creating a complete block, changing the receptor-ligand complex or the basic hormone signal transduction.To screen the inactivating mutations in Exon 6 and Exon 10E of FSHR gene in women diagnosed with PCOS.PCR-RFLP analysis indicated that there were no inactivating mutations found in Exon 6 and Exon 10E. Variations in hormone levels were seen amongst the PCOS patients. There were no inactivating mutations found in FSHR gene of the women diagnosed with PCOS according to the Rotterdam criteria in Vellore population.

  18. A universe of dwarfs and giants: genome size and chromosome evolution in the monocot family Melanthiaceae.

    Science.gov (United States)

    Pellicer, Jaume; Kelly, Laura J; Leitch, Ilia J; Zomlefer, Wendy B; Fay, Michael F

    2014-03-01

    • Since the occurrence of giant genomes in angiosperms is restricted to just a few lineages, identifying where shifts towards genome obesity have occurred is essential for understanding the evolutionary mechanisms triggering this process. • Genome sizes were assessed using flow cytometry in 79 species and new chromosome numbers were obtained. Phylogenetically based statistical methods were applied to infer ancestral character reconstructions of chromosome numbers and nuclear DNA contents. • Melanthiaceae are the most diverse family in terms of genome size, with C-values ranging more than 230-fold. Our data confirmed that giant genomes are restricted to tribe Parideae, with most extant species in the family characterized by small genomes. Ancestral genome size reconstruction revealed that the most recent common ancestor (MRCA) for the family had a relatively small genome (1C = 5.37 pg). Chromosome losses and polyploidy are recovered as the main evolutionary mechanisms generating chromosome number change. • Genome evolution in Melanthiaceae has been characterized by a trend towards genome size reduction, with just one episode of dramatic DNA accumulation in Parideae. Such extreme contrasting profiles of genome size evolution illustrate the key role of transposable elements and chromosome rearrangements in driving the evolution of plant genomes. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. Untangling the Contributions of Sex-Specific Gene Regulation and X-Chromosome Dosage to Sex-Biased Gene Expression in Caenorhabditis elegans

    Science.gov (United States)

    Kramer, Maxwell; Rao, Prashant; Ercan, Sevinc

    2016-01-01

    Dosage compensation mechanisms equalize the level of X chromosome expression between sexes. Yet the X chromosome is often enriched for genes exhibiting sex-biased, i.e., imbalanced expression. The relationship between X chromosome dosage compensation and sex-biased gene expression remains largely unexplored. Most studies determine sex-biased gene expression without distinguishing between contributions from X chromosome copy number (dose) and the animal’s sex. Here, we uncoupled X chromosome dose from sex-specific gene regulation in Caenorhabditis elegans to determine the effect of each on X expression. In early embryogenesis, when dosage compensation is not yet fully active, X chromosome dose drives the hermaphrodite-biased expression of many X-linked genes, including several genes that were shown to be responsible for hermaphrodite fate. A similar effect is seen in the C. elegans germline, where X chromosome dose contributes to higher hermaphrodite X expression, suggesting that lack of dosage compensation in the germline may have a role in supporting higher expression of X chromosomal genes with female-biased functions in the gonad. In the soma, dosage compensation effectively balances X expression between the sexes. As a result, somatic sex-biased expression is almost entirely due to sex-specific gene regulation. These results suggest that lack of dosage compensation in different tissues and developmental stages allow X chromosome copy number to contribute to sex-biased gene expression and function. PMID:27356611

  20. Roles for Dam methylation in bacterial chromosome replication

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Koch, Birgit; Skovgaard, Ole

    GATC sequences in the DNA of Escherichia coli and related species are methylated at the adenine residue by DNA adenine methyltransferase (DamMT). These methylated residues and/or the level of DamMT influence initiation of chromosome replication from the replication origin, oriC, which contain...... for about one third of the cell cycle. During sequestration at least three mechanisms operate to lower the activity of the initiator protein, DnaA. First, the dnaA promoter, which also contains an excess of GATC sequences, is sequestered for the same period of time as oriC to prevent de novo DnaA synthesis....... Second, new DnaA binding sites outside oriC are generated by replication which serve to titrate free DNA protein. Third, after initiation, DnaA-ATP is converted to inactive DnaA-ADP by a process called RIDA (regulatory inactivation of DnaA), which is dependent on the beta-clamp of DNA polymerase III...

  1. Flow Analysis and Sorting of Plant Chromosomes

    Czech Academy of Sciences Publication Activity Database

    Vrána, Jan; Cápal, Petr; Šimková, Hana; Karafiátová, Miroslava; Čížková, Jana; Doležel, Jaroslav

    2016-01-01

    Roč. 78, Oct 10 (2016), 5.3.1-5.3.43 ISSN 1934-9300 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : cell cycle synchronization * chromosome genomics * chromosome isolation Subject RIV: EB - Genetics ; Molecular Biology

  2. Chromosome studies in Cashew ( Anacardium occidentale L ...

    African Journals Online (AJOL)

    Despite the increased cultivation of cashew as a commodity crop in sub-Sahara Africa, Asia and South America there are few chromosome studies on it. The present study investigates number, structure and behavior of chromosome in cashew populations growing in Nigeria. Cytological examination of these populations ...

  3. The Barley Chromosome 5 Linkage Map

    DEFF Research Database (Denmark)

    Jensen, J.; Jørgensen, Jørgen Helms

    1975-01-01

    The literature is surveyed for data on recombination between loci on chromosome 5 of barley; 13 loci fall into the category “mapped” loci, more than 20 into the category “associated” loci and nine into the category “loci once suggested to be on chromosome 5”. A procedure was developed...

  4. Cytometric analysis of irradiation damaged chromosomes

    International Nuclear Information System (INIS)

    Wilder, M.E.; Raju, M.R.

    1982-01-01

    Irradiation of cells in interphase results in dose-dependent damage to DNA which is discernable by flow-cytometric analysis of chromosomes. The quantity (and possibly the quality) of chromosomal changes is different in survival-matched doses of x and α irradiation. It may, therefore, be possible to use these methods for analysis of dose and type of exposure in unknown cases

  5. Chromosomal evolution and phylogenetic analyses in Tayassu ...

    Indian Academy of Sciences (India)

    Chromosome preparation and karyotype description. The material analysed consists of chromosome preparations of the tayassuid species T. pecari (three individuals) and. P. tajacu (four individuals) and were made from short-term lymphocyte cultures of whole blood samples using standard protocols (Chaves et al. 2002).

  6. AFM image of an entire polygene chromosome

    International Nuclear Information System (INIS)

    Li Minqian; Takeuchi; Ikai, A.

    1994-01-01

    The author present AFM images of an entire polygene chromosome of Drosophila for the first time. Comparing with conventional optical microscope, the AFM image of the polygene chromosomes provides much higher resolution and 3-D measurement capability which will lead to finer scale gene mapping and identification

  7. A sexy spin on nonrandom chromosome segregation.

    Science.gov (United States)

    Charville, Gregory W; Rando, Thomas A

    2013-06-06

    Nonrandom chromosome segregation is an intriguing phenomenon linked to certain asymmetric stem cell divisions. In a recent report in Nature, Yadlapalli and Yamashita (2013) observe nonrandom segregation of X and Y chromosomes in Drosophila germline stem cells and shed light on the complex mechanisms of this fascinating process. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Driving towards ecotechnologies.

    Science.gov (United States)

    Najjar, Devora A; Normandin, Avery M; Strait, Elizabeth A; Esvelt, Kevin M

    2017-12-01

    The prospect of using genetic methods to target vector, parasite, and reservoir species offers tremendous potential benefits to public health, but the use of genome editing to alter the shared environment will require special attention to public perception and community governance in order to benefit the world. Public skepticism combined with the media scrutiny of gene drive systems could easily derail unpopular projects entirely, especially given the potential for trade barriers to be raised against countries that employ self-propagating gene drives. Hence, open and community-guided development of thoughtfully chosen applications is not only the most ethical approach, but also the most likely to overcome the economic, social, and diplomatic barriers. Here we review current and past attempts to alter ecosystems using biological methods, identify key determinants of social acceptance, and chart a stepwise path for developers towards safe and widely supported use.

  9. Control rod drives

    International Nuclear Information System (INIS)

    Asano, Hiromitsu.

    1979-01-01

    Purpose: To drive control rods at an optimum safety speed corresponding to the reactor core output. Constitution: The reactor power is detected by a neutron detector and the output signal is applied to a process computer. The process computer issues a signal representing the reactor core output, which is converted through a function generator into a signal representing the safety speed of control rods. The converted signal is further supplied to a V/F converter and converted into a pulse signal. The pulse signal is inputted to a step motor driving circuit, which actuates a step motor to operate the control rods always at a safety speed corresponding to the reactor core power. (Furukawa, Y.)

  10. Drive-by-Downloads

    Energy Technology Data Exchange (ETDEWEB)

    Narvaez, Julia; Endicott-Popovsky, Barbara E.; Seifert, Christian; Aval, Chiraag U.; Frincke, Deborah A.

    2010-02-01

    Abstract: Drive-by-downloads are malware that push, and then execute, malicious code on a client system without the user's consent. The purpose of this paper is to introduce a discussion of the usefulness of antivirus software for detecting the installation of such malware, providing groundwork for future studies. Client honeypots collected drive-by malware which was then evaluated using common antivirus products. Initial analysis showed that most of such antivirus products identified less than 70% of these highly polymorphic malware programs. Also, it was observed that the antivirus products tested, even when successfully detecting this malware, often failed to classify it, leading to the conclusion that further work could involve not only developing new behavioral detection technologies, but also empirical studies that improve general understanding of these threats. Toward that end, one example of malicious code was analyzed behaviorally to provide insight into next steps for the future direction of this research.

  11. Safety rod driving device

    International Nuclear Information System (INIS)

    Murakami, Kiyonobu; Kurosaki, Akira.

    1988-01-01

    Purpose: To rapidly insert safety rods for a criticality experiment device into a reactor core container to stop the criticality reaction thereby prevent reactivity accidents. Constitution: A cylinder device having a safety rod as a cylinder rod attached with a piston at one end is constituted. The piston is elevated by pressurized air and attracted and fixed by an electromagnet which is a stationary device disposed at the upper portion of the cylinder. If the current supply to the electromagnet is disconnected, the safety rod constituting the cylinder rod is fallen together with the piston to the lower portion of the cylinder. Since the cylinder rod driving device has neither electrical motor nor driving screw as in the conventional device, necessary space can be reduced and the weight is decreased. In addition, since the inside of the nuclear reactor can easily be shielded completely from the external atmosphere, leakage of radioactive materials can be prevented. (Horiuchi, T.)

  12. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Futatsugi, Masao; Goto, Mikihiko.

    1976-01-01

    Purpose: To provide a control rod drive mechanism using water as an operating source, which prevents a phenomenon for forming two-layers of water in the neighbourhood of a return nozzle in a reactor to limit formation of excessive thermal stress to improve a safety. Constitution: In the control rod drive mechanism of the present invention, a heating device is installed in the neighbourhood of a pressure container for a reactor. This heating device is provided to heat return water in the reactor to a level equal to the temperature of reactor water thereby preventing a phenomenon for forming two-layers of water in the reactor. This limits formation of thermal stress in the return nozzle in the reactor. Accordingly, it is possible to minimize damages in the return nozzle portion and yet a possibility of failure in reactor water. (Kawakami, Y.)

  13. A rotary drive

    International Nuclear Information System (INIS)

    Causer, R.

    1983-01-01

    A rotary drive for a manipulator or teleoperator comprises a ring member freely rotatable about an eccentric boss extending from an input driver shaft. The ring member has a tapered rim portion wedged between two resiliently biassed friction rings of larger diameter than the ring member and coaxial with the driver shaft, and the ring member is rotatably connected to an output driven shaft. The rotary drive provides a considerable velocity ratio, and also provides a safety feature in that friction between the rim portion and the friction rings only causes rotation of the driven shaft if the load on the driven shaft is less than a certain limiting value. This limiting value may be varied by adjusting the resilient bias on the friction rings. (author)

  14. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  15. Horse domestication and conservation genetics of Przewalski's horse inferred from sex chromosomal and autosomal sequences.

    Science.gov (United States)

    Lau, Allison N; Peng, Lei; Goto, Hiroki; Chemnick, Leona; Ryder, Oliver A; Makova, Kateryna D

    2009-01-01

    Despite their ability to interbreed and produce fertile offspring, there is continued disagreement about the genetic relationship of the domestic horse (Equus caballus) to its endangered wild relative, Przewalski's horse (Equus przewalskii). Analyses have differed as to whether or not Przewalski's horse is placed phylogenetically as a separate sister group to domestic horses. Because Przewalski's horse and domestic horse are so closely related, genetic data can also be used to infer domestication-specific differences between the two. To investigate the genetic relationship of Przewalski's horse to the domestic horse and to address whether evolution of the domestic horse is driven by males or females, five homologous introns (a total of approximately 3 kb) were sequenced on the X and Y chromosomes in two Przewalski's horses and three breeds of domestic horses: Arabian horse, Mongolian domestic horse, and Dartmoor pony. Five autosomal introns (a total of approximately 6 kb) were sequenced for these horses as well. The sequences of sex chromosomal and autosomal introns were used to determine nucleotide diversity and the forces driving evolution in these species. As a result, X chromosomal and autosomal data do not place Przewalski's horses in a separate clade within phylogenetic trees for horses, suggesting a close relationship between domestic and Przewalski's horses. It was also found that there was a lack of nucleotide diversity on the Y chromosome and higher nucleotide diversity than expected on the X chromosome in domestic horses as compared with the Y chromosome and autosomes. This supports the hypothesis that very few male horses along with numerous female horses founded the various domestic horse breeds. Patterns of nucleotide diversity among different types of chromosomes were distinct for Przewalski's in contrast to domestic horses, supporting unique evolutionary histories of the two species.

  16. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed...

  17. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Mizuno, Katsuyuki.

    1976-01-01

    Object: To restrict the reduction in performance due to stress corrosion cracks by making use of condensate produced in a turbine steam condenser. Structure: Water produced in a turbine steam condenser is forced into a condensed water desalting unit by low pressure condensate pump. The condensate is purified and then forced by a high pressure condensate pump into a feedwater heater for heating before it is returned to the reactor by a feedwater pump. Part of the condensate issuing from the condensate desalting unit is branched from the remaining portion at a point upstream the pump and is withdrawn into a control rod drive water pump after passing through a motordriven bypass valve, an orifice and a condenser water level control valve, is pressurized in the control rod drive water desalting unit and supplied to a control rod drive water pressure system. The control rod is vertically moved by the valve operation of the water pressure system. Since water of high oxygen concentration does not enter during normal operation, it is possible to prevent the stress cracking of the stainless steel apparatus. (Nakamura, S.)

  18. Motor car driving; Kraftfahrzeugfuehrung

    Energy Technology Data Exchange (ETDEWEB)

    Juergensohn, T. [Technische Univ. Berlin (Germany). ISS-Fahrzeugtechnik; Timpe, K.P. (eds.) [Technische Univ. Berlin (DE). Zentrum Mensch-Maschine-Systeme (ZMMS)

    2001-07-01

    This is the first comprehensive book on motor car driving, i.e. all aspects of motor car technology that cannot be looked at separately from the needs, characteristics and limitations of the human driver. This includes ergonomics as well as the design of the driver interface in consideration of the findings of cognitive science, problems of driving simulation in the context of simulation of technical systems, problems relating to optimal car automation up to traffic psychology. The book is in honour of Prof. Dr. Willumeit who died in summer 2000. Prof. Willumeit was one of the few scientists in Germany who had been an expert on all aspects of motor car driving for many years. [German] Erstmalig wird das Thema der Fahrzeugfuehrung geschlossen dargestellt. Die Thematik der 'Kraftfahrzeugfuehrung' umfasst in diesem Zusammenhang alle Aspekte der Kraftfahrzeugtechnik, die nicht isoliert von den Erfordernissen, Eigenschaften und Grenzen des menschlichen Fahrers betrachtet werden koennen. Dies beinhaltet u.a. Probleme der Ergonomie, aber auch Fragen nach einer kognitionswissenschaftlich unterstuetzten Schnittstellengestaltung, Fragen der Simulation des Fahrverhalten im Kontext der Simulation technischer Systeme oder Fragen einer optimalen Fahrzeugautomatisierung bis hin zu verkehrspsychologischen Aspekten. Das Buch ist als Gedenkband fuer Prof. Dr. Willumeit konzipiert, der im Sommer 2000 verstarb. Prof. Willumeit war einer der wenigen Wissenschaftler in Deutschland, der ueber viele Jahre diese Thematik der Kraftfahrzeugfuehrung in ihrer vollen Breite verfolgte. (orig.)

  19. Control rod drive

    International Nuclear Information System (INIS)

    Watando, Kosaku; Tanaka, Yuzo; Mizumura, Yasuhiro; Hosono, Kazuya.

    1975-01-01

    Object: To provide a simple and compact construction of an apparatus for driving a drive shaft inside with a magnetic force from the outside of the primary system water side. Structure: The weight of a plunger provided with an attraction plate is supported by a plunger lift spring means so as to provide a buffer action at the time of momentary movement while also permitting the load on lift coil to be constituted solely by the load on the drive shaft. In addition, by arranging the attraction plate and lift coil so that they face each other with a small gap there-between, it is made possible to reduce the size and permit efficient utilization of the attracting force. Because of the small size, cooling can be simply carried out. Further, since there is no mechanical penetration portion, there is no possibility of leakage of the primary system water. Furthermore, concentration of load on a latch pin is prevented by arranging so that with a structure the load of the control rod to be directly beared through the scrum latch. (Kamimura, M.)

  20. Chromosome behaviour in Rhoeo spathacea var. variegata.

    Science.gov (United States)

    Lin, Y J

    1980-01-01

    Rhoeo spathacea var. variegata is unusual in that its twelve chromosomes are arranged in a ring at meiosis. The order of the chromosomes has been established, and each chromosome arm has been designated a letter in accordance with the segmental interchange theory. Chromosomes are often irregularly orientated at metaphase I. Chromosomes at anaphase I are generally distributed equally (6-6, 58.75%) although not necessarily balanced. Due to adjacent distribution, 7-5 distribution at anaphase I was frequently observed (24.17%), and due to lagging, 6-1-5 and 5-2-5 distributions were also observed (10.83% and 3.33% respectively). Three types of abnormal distribution, 8-4, 7-1-4 and 6-2-4 were observed very infrequently (2.92% total), and their possible origins are discussed. Irregularities, such as adjacent distribution and lagging, undoubtedly reduce the fertility of the plant because of the resulting unbalanced gametes.

  1. Chromosome reduction in Eleocharis maculosa (Cyperaceae).

    Science.gov (United States)

    da Silva, C R M; González-Elizondo, M S; Laforga Vanzela, A L

    2008-01-01

    Chromosome numbers in Cyperaceae lower than the typical basic number x = 5 have been described for only three species: Rhynchospora tenuis (n = 2), Fimbristylis umbellaris (n = 3) and Eleocharis subarticulata (n = 3). Eleocharis maculosa is recorded here as the fourth species of Cyperaceae that has a chromosome number lower than 2n = 10, with 2n = 8, 7 and 6. The karyotype differentiation in E. maculosa was studied using conventional staining (mitosis and meiosis), FISH with 45S and 5S rDNA and telomere probes. The results allow us to determine which chromosomes of the chromosome race with 2n = 10 fused to form the remaining reduced numbers, as well as to understand how the symploidy and translocation mechanisms were important in karyotype differentiation and the formation of chromosome races in Eleocharis. Copyright 2008 S. Karger AG, Basel.

  2. Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

    International Nuclear Information System (INIS)

    Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

    1982-01-01

    Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with 60 CO gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of 60 CO radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. The authors found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents

  3. Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

    International Nuclear Information System (INIS)

    Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

    1982-01-01

    Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with 60 Co gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of 60 Co radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents

  4. Cationic antimicrobial peptides inactivate Shiga toxin-encoding bacteriophages

    Science.gov (United States)

    Del Cogliano, Manuel E.; Hollmann, Axel; Martinez, Melina; Semorile, Liliana; Ghiringhelli, Pablo D.; Maffía, Paulo C.; Bentancor, Leticia V.

    2017-12-01

    Shiga toxin (Stx) is the principal virulence factor during Shiga toxin-producing Escherichia coli (STEC) infections. We have previously reported the inactivation of bacteriophage encoding Stx after treatment with chitosan, a linear polysaccharide polymer with cationic properties. Cationic antimicrobial peptides (cAMPs) are short linear aminoacidic sequences, with a positive net charge, which display bactericidal or bacteriostatic activity against a wide range of bacterial species. They are promising novel antibiotics since they have shown bactericidal effects against multiresistant bacteria. To evaluate whether cationic properties are responsible for bacteriophage inactivation, we tested seven cationic peptides with proven antimicrobial activity as anti-bacteriophage agents, and one random sequence cationic peptide with no antimicrobial activity as a control. We observed bacteriophage inactivation after incubation with five cAMPs, but no inactivating activity was observed with the random sequence cationic peptide or with the non alpha helical cAMP Omiganan. Finally, to confirm peptide-bacteriophage interaction, zeta potential was analyzed by following changes on bacteriophage surface charges after peptide incubation. According to our results we could propose that: 1) direct interaction of peptides with phage is a necessary step for bacteriophage inactivation, 2) cationic properties are necessary but not sufficient for bacteriophage inactivation, and 3) inactivation by cationic peptides could be sequence (or structure) specific. Overall our data suggest that these peptides could be considered a new family of molecules potentially useful to decrease bacteriophage replication and Stx expression.

  5. Cationic Antimicrobial Peptides Inactivate Shiga Toxin-Encoding Bacteriophages

    Directory of Open Access Journals (Sweden)

    Manuel E. Del Cogliano

    2017-12-01

    Full Text Available Shiga toxin (Stx is the principal virulence factor during Shiga toxin-producing Escherichia coli (STEC infections. We have previously reported the inactivation of bacteriophage encoding Stx after treatment with chitosan, a linear polysaccharide polymer with cationic properties. Cationic antimicrobial peptides (cAMPs are short linear aminoacidic sequences, with a positive net charge, which display bactericidal or bacteriostatic activity against a wide range of bacterial species. They are promising novel antibiotics since they have shown bactericidal effects against multiresistant bacteria. To evaluate whether cationic properties are responsible for bacteriophage inactivation, we tested seven cationic peptides with proven antimicrobial activity as anti-bacteriophage agents, and one random sequence cationic peptide with no antimicrobial activity as a control. We observed bacteriophage inactivation after incubation with five cAMPs, but no inactivating activity was observed with the random sequence cationic peptide or with the non-alpha helical cAMP Omiganan. Finally, to confirm peptide-bacteriophage interaction, zeta potential was analyzed by following changes on bacteriophage surface charges after peptide incubation. According to our results we could propose that: (1 direct interaction of peptides with phage is a necessary step for bacteriophage inactivation, (2 cationic properties are necessary but not sufficient for bacteriophage inactivation, and (3 inactivation by cationic peptides could be sequence (or structure specific. Overall our data suggest that these peptides could be considered a new family of molecules potentially useful to decrease bacteriophage replication and Stx expression.

  6. Energy Landscapes of Folding Chromosomes

    Science.gov (United States)

    Zhang, Bin

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  7. The Y chromosome of the Atelidae family (Platyrrhini): study by chromosome microdissection.

    Science.gov (United States)

    Gifalli-Iughetti, C; Koiffmann, C P

    2009-01-01

    In order to study the intergeneric variability of the Y chromosome, we describe the hybridization of the Y chromosome of Brachytelesarachnoides, obtained by microdissection, to metaphases of Atelesbelzebuthmarginatus, Lagothrixlagothricha, and Alouatta male specimens. Brachytelesarachnoides (Atelinae) has 62 chromosomes and a very small Y chromosome. Our results showed that the Brachytelesarachnoides Y chromosome probe hybridized to Lagothrixlagothricha metaphases yielding one hybridization signal on only the tiny Y chromosome, and when hybridized with Atelesbelzebuthmarginatus metaphases it yielded one hybridization signal on two thirds of the small acrocentric Y chromosome. However, no hybridization signal was observed in Alouatta metaphases (subfamily Alouattinae), a closely related genus in the Atelidae family. Furthermore, our data support a close phylogenetic relationship among Brachyteles, Ateles, and Lagothrix and their placement in the Atelinae subfamily, but exclude Alouatta from this group indicating its placement as basal to this group. Copyright 2009 S. Karger AG, Basel.

  8. Y-chromosome evolution: emerging insights into processes of Y-chromosome degeneration.

    Science.gov (United States)

    Bachtrog, Doris

    2013-02-01

    The human Y chromosome is intriguing not only because it harbours the master-switch gene that determines gender but also because of its unusual evolutionary history. The Y chromosome evolved from an autosome, and its evolution has been characterized by massive gene decay. Recent whole-genome and transcriptome analyses of Y chromosomes in humans and other primates, in Drosophila species and in plants have shed light on the current gene content of the Y chromosome, its origins and its long-term fate. Furthermore, comparative analysis of young and old Y chromosomes has given further insights into the evolutionary and molecular forces triggering Y-chromosome degeneration and into the evolutionary destiny of the Y chromosome.

  9. Self-rated driving and driving safety in older adults.

    Science.gov (United States)

    Ross, Lesley A; Dodson, Joan E; Edwards, Jerri D; Ackerman, Michelle L; Ball, Karlene

    2012-09-01

    Many U.S. states rely on older adults to self-regulate their driving and determine when driving is no longer a safe option. However, the relationship of older adults' self-rated driving in terms of actual driving competency outcomes is unclear. The current study investigates self-rated driving in terms of (1) systematic differences between older adults with high (good/excellent) versus low (poor/fair/average) self-ratings, and (2) the predictive nature of self-rated driving to adverse driving outcomes in older adults (n=350; mean age 73.9, SD=5.25, range 65-91). Adverse driving outcomes included self-reported incidences of (1) being pulled over by the police, (2) receiving a citation, (3) receiving a recommendation to cease or limit driving, (4) crashes, and (5) state-reported crashes. Results found that older drivers with low self-ratings reported more medical conditions, less driving frequency, and had been given more suggestions to stop/limit their driving; there were no other significant differences between low and high self-raters. Logistic regression revealed older drivers were more likely to have a state-reported crash and receive a suggestion to stop or limit driving. Men were more likely to report all adverse driving outcomes except for receiving a suggestion to stop or limit driving. Regarding self-rated driving, older adults with high ratings were 66% less likely (OR=0.34, 95% CI=0.14-0.85) to have received suggestions to limit or stop driving after accounting for demographics, health and driving frequency. Self-ratings were not predictive of other driving outcomes (being pulled over by the police, receiving a citation, self-reported crashes, or state-reported crashes, ps>0.05). Most older drivers (85.14%) rated themselves as either good or excellent drivers regardless of their actual previous citation or crash rates. Self-rated driving is likely not related to actual driving proficiency as indicated by previous crash involvement in older adults

  10. A Turner Syndrome Patient Carrying a Mosaic Distal X Chromosome Marker

    Directory of Open Access Journals (Sweden)

    Roberto L. P. Mazzaschi

    2014-01-01

    Full Text Available A skin sample from a 17-year-old female was received for routine karyotyping with a set of clinical features including clonic seizures, cardiomyopathy, hepatic adenomas, and skeletal dysplasia. Conventional karyotyping revealed a mosaic Turner syndrome karyotype with a cell line containing a small marker of X chromosome origin. This was later confirmed on peripheral blood cultures by conventional G-banding, fluorescence in situ hybridisation and microarray analysis. Similar Turner mosaic marker chromosome cases have been previously reported in the literature, with a variable phenotype ranging from the mild “classic” Turner syndrome to anencephaly, agenesis of the corpus callosum, complex heart malformation, and syndactyly of the fingers and toes. This case report has a phenotype that is largely discordant with previously published cases as it lies at the severe end of the Turner variant phenotype scale. The observed cytogenetic abnormalities in this study may represent a coincidental finding, but we cannot exclude the possibility that the marker has a nonfunctioning X chromosome inactivation locus, leading to functional disomy of those genes carried by the marker.

  11. Luciferase inactivation in the luminous marine bacterium Vibrio harveyi.

    Science.gov (United States)

    Reeve, C A; Baldwin, T O

    1981-06-01

    Luciferase was rapidly inactivated in stationary-phase cultures of the wild type of the luminous marine bacterium Vibrio harveyi, but was stable in stationary-phase cultures of mutants of V. harveyi that are nonluminous without exogenous aldehyde, termed the aldehyde-deficient mutants. The inactivation in the wild type was halted by cell lysis and was slowed or stopped by O2 deprivation or by addition of KCN and NaF or of chloramphenicol. If KCN and NaF or chloramphenicol were added to a culture before the onset of luciferase inactivation, then luciferase inactivation did not occur. However, if these inhibitors were added after the onset of luciferase inactivation, then luciferase inactivation continued for about 2 to 3 h before the inactivation process stopped. The onset of luciferase inactivation in early stationary-phase cultures of wild-type cell coincided with a slight drop in the intracellular adenosine 5'-triphosphate (ATP) level from a relatively constant log-phase value of 20 pmol of ATP per microgram of soluble cell protein. Addition of KCN and NaF to a culture shortly after this drop in ATP caused a rapid decrease in the ATP level to about 4 pmol of ATP per microgram whereas chloramphenicol added at this same time caused a transient increase in ATP level to about 25 pmol/microgram. The aldehyde-deficient mutant (M17) showed a relatively constant log-phase ATP level identical with that of the wild-type cells, but rather than decreasing in early stationary phase, the ATP level increased to a value twice that in log-phase cells. We suggest that the inactivation of luciferase is dependent on the synthesis of some factor which is produced during stationary phase and is itself unstable, and whose synthesis is blocked by chloramphenicol or cyanide plus fluoride.

  12. Speciation with gene flow in equids despite extensive chromosomal plasticity.

    Science.gov (United States)

    Jónsson, Hákon; Schubert, Mikkel; Seguin-Orlando, Andaine; Ginolhac, Aurélien; Petersen, Lillian; Fumagalli, Matteo; Albrechtsen, Anders; Petersen, Bent; Korneliussen, Thorfinn S; Vilstrup, Julia T; Lear, Teri; Myka, Jennifer Leigh; Lundquist, Judith; Miller, Donald C; Alfarhan, Ahmed H; Alquraishi, Saleh A; Al-Rasheid, Khaled A S; Stagegaard, Julia; Strauss, Günter; Bertelsen, Mads Frost; Sicheritz-Ponten, Thomas; Antczak, Douglas F; Bailey, Ernest; Nielsen, Rasmus; Willerslev, Eske; Orlando, Ludovic

    2014-12-30

    Horses, asses, and zebras belong to a single genus, Equus, which emerged 4.0-4.5 Mya. Although the equine fossil record represents a textbook example of evolution, the succession of events that gave rise to the diversity of species existing today remains unclear. Here we present six genomes from each living species of asses and zebras. This completes the set of genomes available for all extant species in the genus, which was hitherto represented only by the horse and the domestic donkey. In addition, we used a museum specimen to characterize the genome of the quagga zebra, which was driven to extinction in the early 1900s. We scan the genomes for lineage-specific adaptations and identify 48 genes that have evolved under positive selection and are involved in olfaction, immune response, development, locomotion, and behavior. Our extensive genome dataset reveals a highly dynamic demographic history with synchronous expansions and collapses on different continents during the last 400 ky after major climatic events. We show that the earliest speciation occurred with gene flow in Northern America, and that the ancestor of present-day asses and zebras dispersed into the Old World 2.1-3.4 Mya. Strikingly, we also find evidence for gene flow involving three contemporary equine species despite chromosomal numbers varying from 16 pairs to 31 pairs. These findings challenge the claim that the accumulation of chromosomal rearrangements drive complete reproductive isolation, and promote equids as a fundamental model for understanding the interplay between chromosomal structure, gene flow, and, ultimately, speciation.

  13. Low Sex Drive in Women

    Science.gov (United States)

    Low sex drive in women Overview Women's sexual desires naturally fluctuate over the years. Highs and lows commonly coincide ... used for mood disorders also can cause low sex drive in women. If your lack of interest ...

  14. Marijuana and actual driving performance

    Science.gov (United States)

    1993-11-01

    This report concerns the effects of marijuana smoking on actual driving performance. It presents the results of one pilot and three actual driving studies. The pilot study's major purpose was to establish the THC dose current marijuana users smoke to...

  15. Distracted Driving Raises Crash Risk

    Science.gov (United States)

    ... this issue Health Capsule Distracted Driving Raises Crash Risk En español Send us your comments Video technology ... distracted driving, especially among new drivers, raises the risk for car crashes and near crashes. The study ...

  16. Inactivation of viruses in municipal effluent by chlorine.

    OpenAIRE

    Hajenian, H. G.; Butler, M.

    1980-01-01

    The influence of pH and temperature on the efficiency of chlorine inactivation of two unrelated picornaviruses in a typical urban wastewater effluent was examined. Temperature, unlike pH, had relatively little effect on the rate of inactivation. The pH effect was complex and the two viruses differed. The f2 coliphage was more sensitive to chlorine at low pH, but at all values there was a threshold above which additional chlorine resulted in very rapid inactivation. The amount of chlorine requ...

  17. Inactivation of human and simian rotaviruses by ozone

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, J.M.; Chen, Y.S.; Lindburg, K.; Morales, D.

    1987-09-01

    The inactivation of simian rotavirus Sa-11 and human rotavirus type 2 (Wa) by ozone was compared at 4/sup 0/C by using single-particle virus stocks. Although the human strain was clearly more sensitive, both virus types were rapidly inactivated by ozone concentrations of 0.25 mg/liter or greater at all pH levels tested. Comparison of the virucidal activity of ozone with that of chlorine in identical experiments indicated little significant difference in rotavirus-inactivating efficiencies when the disinfectants were used at concentrations of 0.25 mg/liter or greater.

  18. Chromatid Painting for Chromosomal Inversion Detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the continued development of a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and...

  19. Chromatid Painting for Chromosomal Inversion Detection, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and inversions) have profound genetic...

  20. Automatic Metaphase Finding by Inter-Chromosome Extrema Profile Analysis

    National Research Council Canada - National Science Library

    Vega-Alvarado, Leticia

    2001-01-01

    ...-level inter-chromosome coarseness features in microscopic images of metaphase spreads, and allows to quantity the texture of the cytological objects analysing the intensity profile between chromosome...

  1. Label Free Chromosome Translocation Detection with Silicon nanowires

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Andersen, Karsten Brandt; Frøhling, Kasper Bayer

    HROMOSOME translocation, which is a rearrangement of arms between two chromosomes, is a major group of chromosome abnormalities leading to cancer. As a result, two derivative chromosomes with sequences coming from both chromosomes are formed. The current translocation detection method is a Fluore......HROMOSOME translocation, which is a rearrangement of arms between two chromosomes, is a major group of chromosome abnormalities leading to cancer. As a result, two derivative chromosomes with sequences coming from both chromosomes are formed. The current translocation detection method...

  2. Nuclear refueling platform drive system

    International Nuclear Information System (INIS)

    Busch, F.R.; Faulstich, D.L.

    1992-01-01

    This patent describes a drive system. It comprises: a gantry including a bridge having longitudinal and transverse axes and supported by spaced first and second end frames joined to fist and second end frames joined to first and second drive trucks for moving the bridge along the transverse axis; first means for driving the first drive truck; second means for driving the second drive truck being independent from the first driving means; and means for controlling the first and second driving means for reducing differential transverse travel between the first and second drive trucks, due to a skewing torque acting on the bridge, to less than a predetermined maximum, the controlling means being in the form of an electrical central processing unit and including: a closed-loop first velocity control means for controlling velocity of the first drive truck by providing a first command signal to the first driver means; a close loop second velocity control means for controlling velocity of the second drive truck by providing a second command signal to the second driving means; and an auxiliary closed-loop travel control means

  3. Structure of the human chromosome interaction network.

    Directory of Open Access Journals (Sweden)

    Sergio Sarnataro

    Full Text Available New Hi-C technologies have revealed that chromosomes have a complex network of spatial contacts in the cell nucleus of higher organisms, whose organisation is only partially understood. Here, we investigate the structure of such a network in human GM12878 cells, to derive a large scale picture of nuclear architecture. We find that the intensity of intra-chromosomal interactions is power-law distributed. Inter-chromosomal interactions are two orders of magnitude weaker and exponentially distributed, yet they are not randomly arranged along the genomic sequence. Intra-chromosomal contacts broadly occur between epigenomically homologous regions, whereas inter-chromosomal contacts are especially associated with regions rich in highly expressed genes. Overall, genomic contacts in the nucleus appear to be structured as a network of networks where a set of strongly individual chromosomal units, as envisaged in the 'chromosomal territory' scenario derived from microscopy, interact with each other via on average weaker, yet far from random and functionally important interactions.

  4. Offset Compound Gear Drive

    Science.gov (United States)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  5. Electrical machines and drives

    CERN Document Server

    Hindmarsh, John

    2002-01-01

    Recent years have brought substantial developments in electrical drive technology, with the appearance of highly rated, very-high-speed power-electronic switches, combined with microcomputer control systems.This popular textbook has been thoroughly revised and updated in the light of these changes. It retains its successful formula of teaching through worked examples, which are put in context with concise explanations of theory, revision of equations and discussion of the engineering implications. Numerous problems are also provided, with answers supplied.The third edition in

  6. Electrical machines & drives

    CERN Document Server

    Hammond, P

    1985-01-01

    Containing approximately 200 problems (100 worked), the text covers a wide range of topics concerning electrical machines, placing particular emphasis upon electrical-machine drive applications. The theory is concisely reviewed and focuses on features common to all machine types. The problems are arranged in order of increasing levels of complexity and discussions of the solutions are included where appropriate to illustrate the engineering implications. This second edition includes an important new chapter on mathematical and computer simulation of machine systems and revised discussions o

  7. Measurement of Driving Terms

    CERN Document Server

    Schmidt, F; Faus-Golfe, A

    2001-01-01

    In 2000 a series of MDs has been performed at the SPS to measure resonance driving terms. Theory predicts that these terms can be determined by harmonic analysis of BPM data recorded after applying single kicks at various amplitudes. Strong sextupoles were introduced to create a sizeable amount of nonlinearities. Experiments at injection energy (26 GeV) with single bunch as well as one experiment at 120 GeV with 84 bunches were carried out. The expected nonlinear content is compared to the experimenteal observation.

  8. Chromosomal aberrations in benign prostatic hyperplasia patients

    Directory of Open Access Journals (Sweden)

    Muammer Altok

    2016-01-01

    Full Text Available Purpose: To investigate the chromosomal changes in patients with benign prostatic hyperplasia (BPH. Materials and Methods: A total of 54 patients diagnosed with clinical BPH underwent transurethral prostate resection to address their primary urological problem. All patients were evaluated by use of a comprehensive medical history and rectal digital examination. The preoperative evaluation also included serum prostate-specific antigen (PSA measurement and ultrasonographic measurement of prostate volume. Prostate cancer was detected in one patient, who was then excluded from the study. We performed conventional cytogenetic analyses of short-term cultures of 53 peripheral blood samples obtained from the BPH patients. Results: The mean (±standard deviation age of the 53 patients was 67.8±9.4 years. The mean PSA value of the patients was 5.8±7.0 ng/mL. The mean prostate volume was 53.6±22.9 mL. Chromosomal abnormalities were noted in 5 of the 53 cases (9.4%. Loss of the Y chromosome was the most frequent chromosomal abnormality and was observed in three patients (5.7%. There was no statistically significant relationship among age, PSA, prostate volume, and chromosomal changes. Conclusions: Loss of the Y chromosome was the main chromosomal abnormality found in our study. However, this coexistence did not reach a significant level. Our study concluded that loss of the Y chromosome cannot be considered relevant for the diagnosis of BPH as it is for prostate cancer. Because BPH usually occurs in aging men, loss of the Y chromosome in BPH patients may instead be related to the aging process.

  9. Comparison of two different methods for inactivation of viruses in serum

    DEFF Research Database (Denmark)

    Preuss, T.; Kamstrup, Søren; Kyvsgaard, N.C.

    1997-01-01

    enterovirus (PEV) was inactivated within 3 h, The inactivation with electron-beam irradiation resulted in almost linear curves in a semilogarithmic plot of virus titer versus irradiation dose, reflecting a first-order inactivation, The rate of inactivation was almost twice as fast in the liquid samples...

  10. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  11. Fullerene C60 and graphene photosensibiles for photodynamic virus inactivation

    Science.gov (United States)

    Belousova, I.; Hvorostovsky, A.; Kiselev, V.; Zarubaev, V.; Kiselev, O.; Piotrovsky, L.; Anfimov, P.; Krisko, T.; Muraviova, T.; Rylkov, V.; Starodubzev, A.; Sirotkin, A.; Grishkanich, A.; Kudashev, I.; Kancer, A.; Kustikova, M.; Bykovskaya, E.; Mayurova, A.; Stupnikov, A.; Ruzankina, J.; Afanasyev, M.; Lukyanov, N.; Redka, D.; Paklinov, N.

    2018-02-01

    A solid-phase photosensitizer based on aggregated C60 fullerene and graphene oxide for photodynamic inactivation of pathogens in biological fluids was studied. The most promising technologies of inactivation include the photodynamic effect, which consists in the inactivation of infectious agents by active oxygen forms (including singlet oxygen), formed when light is activated by the photosensitizer introduced into the plasma. Research shows features of solid-phase systems based on graphene and fullerene C60 oxide, which is a combination of an effective inactivating pathogens (for example, influenza viruses) reactive oxygen species formed upon irradiation of the photosensitizer in aqueous and biological fluids, a high photostability fullerene coatings and the possibility of full recovery photosensitizer from the biological environment after the photodynamic action.

  12. Inactivation of rabies diagnostic reagents by gamma radiation

    International Nuclear Information System (INIS)

    Gamble, W.C.; Chappell, W.A.; George, E.H.

    1980-01-01

    Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents

  13. Biocontrol interventions for inactivation of foodborne pathogens on produce

    Science.gov (United States)

    Post-harvest interventions for control of foodborne pathogens on minimally processed foods are crucial for food safety. Biocontrol interventions have the primary objective of developing novel antagonists in combinations with physical and chemical interventions to inactivate pathogenic microbes. Ther...

  14. Use of genetic algorithms for high hydrostatic pressure inactivation ...

    African Journals Online (AJOL)

    ) for high hydrostatic pressure (HHP) inactivation of Bacillus cereus spores, Bacillus subtilis spores and cells, Staphylococcus aureus and Listeria monocytogenes, all in milk buffer, were used to demonstrate the utility of genetic algorithms ...

  15. Inactivation of bacterial cells by cyclotron beams

    Energy Technology Data Exchange (ETDEWEB)

    Yatagai, F [Waseda Univ., Tokyo (Japan). School of Science and Engineering; Takahashi, T; Matsuyama, A

    1975-06-01

    B. subtilis spores, E. coli Bsub(s-1) and E. coli B/r were bombarded with ..cap alpha..-particles and heavy ions of carbon, nitrogen and oxygen accelerated in the IPCR Cyclotron. The RBE versus LETsub(infinity) curve for B. subtilis spores showed a maximum peak at 120 keV/..mu..m, while those for E. coli Bsub(s-1) and E. coli B/r declined without any maximum as LETsub(infinity) values increased. In the region of ..cap alpha..-particles, the effective inactivation cross section (Ssub(eff)) for these three strains increased with increasing LETsub(infinity), and the rates of increase in Ssub(eff) in the LET region from --30 to --150 keV/..mu..m were 15.0, 1.5 and 2.5 times for B. subtilis spores, E. coli Bsub(s-1) and E. coli B/r, respectively. In the case of B. subtilis spores, Ssub(eff) values for heavy ions were almost independent of their energies, but the other two strains showed a considerable dependence upon beam energy. The characteristic LET dependence of Ssub(eff) observed in this study was fairly well explained by the target theory based on microdose concept.

  16. Inactivation of RNA viruses by gamma irradiation

    International Nuclear Information System (INIS)

    Nonomiya, Takashi; Morimoto, Akinori; Iwatsuki, Kazuo; Tsutsumi, Takamasa; Ito, Hitoshi; Yamashiro, Tomio; Ishigaki, Isao.

    1992-01-01

    Four kinds of RNA viruses, Bluetongue virus (BT), Bovine Virus Diarrhea-Mucosal Disease virus (BVD·MD), Bovine Respiratory Syncytial virus (RS), Vesicular Stmatitis virus (VS), were subjected to various doses of gamma irradiation to determine the lethal doses. The D 10 values, which are the dose necessary to decimally reduce infectivity, ranged from 1.5 to 3.4 kGy under frozen condition at dry-ice temperature, and they increased to 2.6 to 5.0 kGy under frozen condition at dry-ice temperature. Serum neutralzing antibody titer of Infectious Bovine Rhinotracheitis (IBR) was not adversely changed by the exposure to 36 kGy of gamma-rays under frozen condition. Analysis of electrophoresis patterns of the bovine serum also reveales that the serum proteins were not remarkably affected, even when exposed to 36 kGy of gamma radiation under frozen condition. The results suggested that gamma irradiation under frozen condition is an effective means for inactivating both DNA and RNA viruses without adversely affecting serum proteins and neutralizing antibody titer. (author)

  17. Inactivation of RNA viruses by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nonomiya, Takashi; Morimoto, Akinori; Iwatsuki, Kazuo; Tsutsumi, Takamasa (Ministry of Agriculture, Forestry and fisheries, Yokohama, Kanagawa (Japan). Animal Quarantine Service); Ito, Hitoshi; Yamashiro, Tomio; Ishigaki, Isao

    1992-09-01

    Four kinds of RNA viruses, Bluetongue virus (BT), Bovine Virus Diarrhea-Mucosal Disease virus (BVD[center dot]MD), Bovine Respiratory Syncytial virus (RS), Vesicular Stmatitis virus (VS), were subjected to various doses of gamma irradiation to determine the lethal doses. The D[sub 10] values, which are the dose necessary to decimally reduce infectivity, ranged from 1.5 to 3.4 kGy under frozen condition at dry-ice temperature, and they increased to 2.6 to 5.0 kGy under frozen condition at dry-ice temperature. Serum neutralzing antibody titer of Infectious Bovine Rhinotracheitis (IBR) was not adversely changed by the exposure to 36 kGy of gamma-rays under frozen condition. Analysis of electrophoresis patterns of the bovine serum also reveales that the serum proteins were not remarkably affected, even when exposed to 36 kGy of gamma radiation under frozen condition. The results suggested that gamma irradiation under frozen condition is an effective means for inactivating both DNA and RNA viruses without adversely affecting serum proteins and neutralizing antibody titer. (author).

  18. Inactivation of bacterial cells by cyclotron beams

    International Nuclear Information System (INIS)

    Yatagai, Fumio; Takahashi, Tadashi; Matsuyama, Akira.

    1975-01-01

    B. subtilis spores, E. coli Bsub(s-1) and E. coli B/r were bombarded with α-particles and heavy ions of carbon, nitrogen and oxygen accelerated in the IPCR Cyclotron. The RBE versus LETsub(infinity) curve for B. subtilis spores showed a maximum peak at 120 keV/μm, while those for E. coli Bsub(s-1) and E. coli B/r declined without any maximum as LETsub(infinity) values increased. In the region of α-particles, the effective inactivation cross section (Ssub(eff)) for these three strains increased with increasing LETsub(infinity), and the rates of increase in Ssub(eff) in the LET region from --30 to --150 keV/μm were 15.0, 1.5 and 2.5 times for B. subtilis spores, E. coli Bsub(s-1) and E. coli B/r, respectively. In the case of B. subtilis spores, Ssub(eff) values for heavy ions were almost independent of their energies, but the other two strains showed a considerable dependence upon beam energy. The characteristic LET dependence of Ssub(eff) observed in this study was fairly well explained by the target theory based on microdose concept. (auth.)

  19. Dry-heat inactivation of "Mycobacterium canettii".

    Science.gov (United States)

    Aboubaker Osman, Djaltou; Garnotel, Eric; Drancourt, Michel

    2017-06-09

    "Mycobacterium canettii" is responsible for non-transmissible lymph node and pulmonary tuberculosis in persons exposed in the Horn of Africa. In the absence of direct human transmission, contaminated water and foodstuffs could be sources of contamination. We investigated the dry-heat inactivation of "M. canettii" alone and mixed into mock-infected foodstuffs by inoculating agar cylinders and milk with 10 4 colony-forming units of "M. canettii" CIPT140010059 and two "M. canettii" clinical strains with Mycobacterium tuberculosis H37Rv as a control. Exposed to 35 °C, M. tuberculosis H37Rv, "M canettii" CIPT140010059 and "M. canettii" 157 exhibited a survival rate of 108, 95 and 81%, which is significantly higher than that of "M. canettii" 173. However, all tested mycobacteria tolerated a 90-min exposure at 45 °C. In the foodstuff models set at 70 °C, no growing mycobacteria were visualized. This study supports the premise that "M. canettii" may survive up to 45 °C; and suggests that contaminated raw drinks and foodstuffs but not cooked ones may be sources of infection for populations.

  20. Chromosome breakage in Vicia faba by ozone

    Energy Technology Data Exchange (ETDEWEB)

    Fetner, R H

    1958-02-15

    Meristem cells of Vicia faba roots were exposed to an atmosphere of ozone and the fraction of cells showing chromosome aberrations were recorded. Chromosome aberrations were observed on a dose-response basis after exposing the seeds to 0.4 wt. percent ozone for 15, 30, and 60 minutes. The results of ozone, x-rays, and ozone and x-ray treatments are presented. A small number of root tips from each group was treated with colchicine and an analysis made of metaphase aberrations. These observations confirmed that the aberrations were all of the chromosome-type.

  1. Genetic and chromosomal effects of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The genetic and chromosomal effects of ionizing radiations deal with those effects in the descendants of the individuals irradiated. The information base concerning genetic and chromosomal injury to humans from radiation is less adequate than is the information base for cancer and leukemia. As a result, it is not possible to make the kinds of quantitative estimates that have been made for carcinogenesis in previous chapters of this book. The chapter includes a detailed explanation of various types of genetic injuries such as chromosomal diseases, x-linked diseases, autosomal dominant diseases, recessive diseases, and irregularly inherited diseases. Quantitative estimates of mutation rates and incidences are given based on atomic bomb survivors data

  2. Chromosome mosaicism in hypomelanosis of Ito.

    Science.gov (United States)

    Ritter, C L; Steele, M W; Wenger, S L; Cohen, B A

    1990-01-01

    Our finding of chromosome mosaicism with a ring 22 in a retarded black boy with hypomelanosis of Ito prompted a review of this "syndrome." Most patients have a variety of non-dermal defects, particularly those affecting CNS function. Among karyotyped patients, most are chromosome mosaics of one sort or another. Hypomelanosis of Ito turns out to be a causable non-specific phenotype, i.e., a clinical marker for chromosome mosaicism of all different types in individuals with a dark enough skin to show lighter patches. Consequently, cytogenetic evaluation is indicated in all patients with this skin finding.

  3. The Barley Chromosome 5 Linkage Map

    DEFF Research Database (Denmark)

    Jensen, J.; Jørgensen, Jørgen Helms

    1975-01-01

    The distances between nine loci on barley chromosome 5 have been studied in five two-point tests, three three-point tests, and one four-point test. Our previous chromosome 5 linkage map, which contained eleven loci mapped from literature data (Jensen and Jørgensen 1975), is extended with four loci......-position is fixed on the map by a locus (necl), which has a good marker gene located centrally in the linkage group. The positions of the other loci are their distances in centimorgans from the 0-position; loci in the direction of the short chromosome arm are assigned positive values and those...

  4. Antibodies against chromosomal beta-lactamase

    DEFF Research Database (Denmark)

    Giwercman, B; Rasmussen, J W; Ciofu, Oana

    1994-01-01

    A murine monoclonal anti-chromosomal beta-lactamase antibody was developed and an immunoblotting technique was used to study the presence of serum and sputum antibodies against Pseudomonas aeruginosa chromosomal group 1 beta-lactamase in patients with cystic fibrosis (CF). The serum antibody...... 1 cephalosporinase. We found a wide range of chromosomal beta-lactamase activity in the sputum samples, with no correlation with basal or induced activity of beta-lactamase expression. The presence of anti-beta-lactamase antibodies in endobronchial sputum could be an important factor in the defense...

  5. Cognitive impairment and driving safety.

    Science.gov (United States)

    Eby, David W; Molnar, Lisa J

    2012-11-01

    As the populations of many countries continue to age, cognitive impairment will likely become more common. Individuals with cognitive impairment pose special challenges for families, health professionals, driving safety professionals, and the larger community, particularly if these older adults depend on driving as their primary means of community mobility. It is vital that we continue to extend our knowledge about the driving behavior of individuals' with cognitive impairment, as well as try to develop effective means of screening and assessing these individuals for fitness to drive and help facilitate their transition to non-driving when appropriate. This special issue is intended to provide researchers and practitioners an opportunity to present the most recent research findings on driving-related issues among older adults with cognitive impairment. The issue contains 11 original contributions from seven countries. The topics covered by these papers are: crash risks; screening, assessment, and fitness to drive; driving performance using a driving simulator; and driving behaviors and driving-related decisions of people with cognitive impairments. Copyright © 2012. Published by Elsevier Ltd.

  6. Parkinson's disease and driving ability

    Science.gov (United States)

    Singh, Rajiv; Pentland, Brian; Hunter, John; Provan, Frances

    2007-01-01

    Objectives To explore the driving problems associated with Parkinson's disease (PD) and to ascertain whether any clinical features or tests predict driver safety. Methods The driving ability of 154 individuals with PD referred to a driving assessment centre was determined by a combination of clinical tests, reaction times on a test rig and an in‐car driving test. Results The majority of cases (104, 66%) were able to continue driving although 46 individuals required an automatic transmission and 10 others needed car modifications. Ability to drive was predicted by the severity of physical disease, age, presence of other associated medical conditions, particularly dementia, duration of disease, brake reaction, time on a test rig and score on a driving test (all pautomatic transmission. A combination of clinical tests and in‐car driving assessment will establish safety to drive, and a number of clinical correlates can be shown to predict the likely outcome and may assist in the decision process. This is the largest series of consecutive patients seen at a driving assessment centre reported to date, and the first to devise a scoring system for on‐road driving assessment. PMID:17178820

  7. Glaucoma and Driving: On-Road Driving Characteristics

    Science.gov (United States)

    Wood, Joanne M.; Black, Alex A.; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia

    2016-01-01

    Purpose To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Methods Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Results Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Conclusions Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness. PMID:27472221

  8. A qualitative exploration of driving stress and driving discourtesy.

    Science.gov (United States)

    Scott-Parker, B; Jones, C M; Rune, K; Tucker, J

    2018-05-31

    Driving courtesy, and conversely driving discourtesy, recently has been of great interest in the public domain. In addition, there has been increasing recognition of the negative impact of stress upon the individual's health and wellbeing, with a plethora of interventions aimed at minimising stress more generally. The research literature regarding driving dis/courtesy, in comparison, is scant, with a handful of studies examining the dis/courteous driving behaviour of road users, and the relationship between driving discourtesy and driving stress. To examine courteous and discourteous driving experiences, and to explore the impact of stress associated with such driving experiences. Thirty-eight drivers (20 females) from the Sunshine Coast region volunteered to participate in one of four 1-1.5 h focus groups. Content analysis used the verbatim utterances captured via an Mp3 device. Three themes pertaining to stressful and discourteous interactions were identified. Theme one pertained to the driving context: road infrastructure (eg, roundabouts, roadwork), vehicles (eg, features), location (eg, country vs city, unfamiliar areas), and temporal aspects (eg, holidays). Theme two pertained to other road users: their behaviour (eg, tailgating, merging), and unknown factors (eg, illicit and licit drug use). Theme three pertained to the self as road user: their own behaviours (eg, deliberate intimidation), and their emotions (eg, angry reaction to other drivers, being in control). Driving dis/courtesy and driving stress is a complex phenomenon, suggesting complex intervention efforts are required. Driving discourtesy was reported as being highly stressful, therefore intervention efforts which encourage driving courtesy and which foster emotional capacity to cope with stressful circumstances appear warranted. Copyright © 2018. Published by Elsevier Ltd.

  9. Glaucoma and Driving: On-Road Driving Characteristics.

    Directory of Open Access Journals (Sweden)

    Joanne M Wood

    Full Text Available To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment.Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years. On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire.Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability.Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness.

  10. Glaucoma and Driving: On-Road Driving Characteristics.

    Science.gov (United States)

    Wood, Joanne M; Black, Alex A; Mallon, Kerry; Thomas, Ravi; Owsley, Cynthia

    2016-01-01

    To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment. Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire. Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability. Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness.

  11. Control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Hiroyasu; Kawamura, Atsuo.

    1979-01-01

    Purpose: To reduce pellet-clad mechanical interactions, as well as improve the fuel safety. Constitution: In the rod drive of a bwr type reactor, an electric motor operated upon intermittent input such as of pulse signals is connected to a control rod. A resolver for converting the rotational angle of the motor to electric signals is connected to the rotational shaft of the motor and the phase difference between the output signal from the resolver and a reference signal is adapted to detect by a comparator. Based on the detection result, the controller is actuated to control a motor for control rod drive so that fine control for the movement of the control rod is made possible. This can reduce the moving distance of the control rod, decrease the thermal stress applied to the control rod and decrease the pellet clad mechanical interaction failures due to thermal expansion between the cladding tube and the pellets caused by abrupt changes in the generated power. (Furukawa, Y.)

  12. Control rod drives

    International Nuclear Information System (INIS)

    Oonuki, Koji.

    1981-01-01

    Purpose: To increase the driving speed of control rods at rapid insertion with an elongate control rod and an extension pipe while ensuring sufficient buffering performance in a short buffering distance, by providing a plurality of buffers to an extension pipe between a control rod drive source and a control rod in LMFBR type reactor. Constitution: First, second and third buffers are respectively provided to an acceleration piston, an extension pipe and a control rod respectively and the insertion positions for each of the buffers are displaced orderly from above to below. Upon disconnection of energizing current for an electromagnet, the acceleration piston, the extension pipe and the control rod are rapidly inserted in one body. The first, second and third buffers are respectively actuated at each of their falling strokes upon rapid insertion respectively, and the acceleration piston, the extension pipe and the control rod receive the deceleration effect in the order correspondingly. Although the compression force is applied to the control rod only near the stroke end, it does not cause deformation. (Kawakami, Y.)

  13. High pressure inactivation of Brettanomyces bruxellensis in red wine.

    Science.gov (United States)

    van Wyk, Sanelle; Silva, Filipa V M

    2017-05-01

    Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Thermal inactivation kinetics of β-galactosidase during bread baking.

    Science.gov (United States)

    Zhang, Lu; Chen, Xiao Dong; Boom, Remko M; Schutyser, Maarten A I

    2017-06-15

    In this study, β-galactosidase was utilized as a model enzyme to investigate the mechanism of enzyme inactivation during bread baking. Thermal inactivation of β-galactosidase was investigated in a wheat flour/water system at varying temperature-moisture content combinations, and in bread during baking at 175 or 205°C. In the wheat flour/water system, the thermostability of β-galactosidase increased with decreased moisture content, and a kinetic model was accurately fitted to the corresponding inactivation data (R 2 =0.99). Interestingly, the residual enzyme activity in the bread crust (about 30%) was hundredfold higher than that in the crumb (about 0.3%) after baking, despite the higher temperature in the crust throughout baking. This result suggested that the reduced moisture content in the crust increased the thermostability of the enzyme. Subsequently, the kinetic model reasonably predicted the enzyme inactivation in the crumb using the same parameters derived from the wheat flour/water system. However, the model predicted a lower residual enzyme activity in the crust compared with the experimental result, which indicated that the structure of the crust may influence the enzyme inactivation mechanism during baking. The results reported can provide a quantitative understanding of the thermal inactivation kinetics of enzyme during baking, which is essential to better retain enzymatic activity in bakery products supplemented with heat-sensitive enzymes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Photodynamic inactivation of foodborne bacteria by eosin Y.

    Science.gov (United States)

    Bonin, E; Dos Santos, A R; Fiori da Silva, A; Ribeiro, L H; Favero, M E; Campanerut-Sá, P A Z; de Freitas, C F; Caetano, W; Hioka, N; Mikcha, J M G

    2018-03-25

    The aim of this study was evaluate the effect of photodynamic inactivation mediated by eosin Y in Salmonella enterica serotype Typhimurium ATCC 14028, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778. Bacteria (10 7 CFU per ml) were incubated with eosin Y at concentrations ranging from 0·1 to 10 μmol l -1 , irradiated by green LED (λ max 490-570 nm) for 5, 10 and 15 min and the cellular viability was determined. Pseudomonas aeruginosa was completely inactivated when treated with 10 μmol l -1 eosin Y for 10 min. Treatments reduced B. cereus and Salm. Typhimurium counts to 2·7 log CFU per ml and 1·7 log CFU per ml, respectively. Escherichia coli counts were slightly reduced. Staphylococcus aureus presented the highest sensitivity, being completely inactivated by eosin Y at 5 μmol l -1 and 5 min of illumination. The reduction of cellular viability of photoinactivated Staph. aureus was also demonstrated by flow cytometry and morphological changes were observed by scanning electron microscopy. Eosin Y in combination with LED produced bacterial inactivation, being a potential candidate for photodynamic inactivation. This study evidenced the efficacy of photodynamic inactivation as a novel and promising alternative to bacterial control. © 2018 The Society for Applied Microbiology.

  16. HIM-8 binds to the X chromosome pairing center and mediates chromosome-specific meiotic synapsis.

    Science.gov (United States)

    Phillips, Carolyn M; Wong, Chihunt; Bhalla, Needhi; Carlton, Peter M; Weiser, Pinky; Meneely, Philip M; Dernburg, Abby F

    2005-12-16

    The him-8 gene is essential for proper meiotic segregation of the X chromosomes in C. elegans. Here we show that loss of him-8 function causes profound X chromosome-specific defects in homolog pairing and synapsis. him-8 encodes a C2H2 zinc-finger protein that is expressed during meiosis and concentrates at a site on the X chromosome known as the meiotic pairing center (PC). A role for HIM-8 in PC function is supported by genetic interactions between PC lesions and him-8 mutations. HIM-8 bound chromosome sites associate with the nuclear envelope (NE) throughout meiotic prophase. Surprisingly, a point mutation in him-8 that retains both chromosome binding and NE localization fails to stabilize pairing or promote synapsis. These observations indicate that stabilization of homolog pairing is an active process in which the tethering of chromosome sites to the NE may be necessary but is not sufficient.

  17. HIM-8 binds to the X chromosome pairing center and mediates chromosome-specific meiotic synapsis

    International Nuclear Information System (INIS)

    Phillips, Carolyn M.; Wong, Chihunt; Bhalla, Needhi; Carlton, Peter M.; Weiser, Pinky; Meneely, Philip M.; Dernburg, Abby F.

    2005-01-01

    The him-8 gene is essential for proper meiotic segregation of the X chromosomes in C. elegans. Here we show that loss of him-8 function causes profound X-chromosome-specific defects in homolog pairing and synapsis.him-8 encodes a C2H2 zinc finger protein that is expressed during meiosis and concentrates at a site on the X chromosome known as themeiotic Pairing Center (PC). A role for HIM-8 in PC function is supported by genetic interactions between PC lesions and him-8 mutations. HIM-8-bound chromosome sites associate with the nuclear envelope (NE)throughout meiotic prophase. Surprisingly, a point mutation in him-8 that retains both chromosome binding and NE localization fails to stabilize pairing or promote synapsis. These observations indicate that stabilization of homolog pairing is an active process in which the tethering of chromosome sites to the NE may be necessary but is not sufficient

  18. Meiotic drive influences the outcome of sexually antagonistic selection at a linked locus.

    Science.gov (United States)

    Patten, M M

    2014-11-01

    Most meiotic drivers, such as the t-haplotype in Mus and the segregation distorter (SD) in Drosophila, act in a sex-specific manner, gaining a transmission advantage through one sex although suffering only the fitness costs associated with the driver in the other. Their inheritance is thus more likely through one of the two sexes, a property they share with sexually antagonistic alleles. Previous theory has shown that pairs of linked loci segregating for sexually antagonistic alleles are more likely to remain polymorphic and that linkage disequilibrium accrues between them. I probe this similarity between drive and sexual antagonism and examine the evolution of chromosomes experiencing these selection pressures simultaneously. Reminiscent of previous theory, I find that: the opportunity for polymorphism increases for a sexually antagonistic locus that is physically linked to a driving locus; the opportunity for polymorphism at a driving locus also increases when linked to a sexually antagonistic locus; and stable linkage disequilibrium accompanies any polymorphic equilibrium. Additionally, I find that drive at a linked locus favours the fixation of sexually antagonistic alleles that benefit the sex in which drive occurs. Further, I show that under certain conditions reduced recombination between these two loci is selectively favoured. These theoretical results provide clear, testable predictions about the nature of sexually antagonistic variation on driving chromosomes and have implications for the evolution of genomic architecture. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  19. Drug-induced premature chromosome condensation (PCC) protocols: cytogenetic approaches in mitotic chromosome and interphase chromatin.

    Science.gov (United States)

    Gotoh, Eisuke

    2015-01-01

    Chromosome analysis is a fundamental technique which is used in wide areas of cytogenetic study including karyotyping species, hereditary diseases diagnosis, or chromosome biology study. Chromosomes are usually prepared from mitotic cells arrested by colcemid block protocol. However, obtaining mitotic chromosomes is often hampered under several circumstances. As a result, cytogenetic analysis will be sometimes difficult or even impossible in such cases. Premature chromosome condensation (PCC) (see Note 1) is an alternative method that has proved to be a unique and useful way in chromosome analysis. Former, PCC has been achieved following cell fusion method (cell-fusion PCC) mediated either by fusogenic viruses (e.g., Sendai virus) or cell fusion chemicals (e.g., polyethylene glycol), but the cell fusion PCC has several drawbacks. The novel drug-induced PCC using protein phosphatase inhibitors was introduced about 20 years ago. This method is much simpler and easier even than the conventional mitotic chromosome preparation protocol use with colcemid block and furthermore obtained PCC index (equivalent to mitotic index for metaphase chromosome) is usually much higher than colcemid block method. Moreover, this method allows the interphase chromatin to be condensed to visualize like mitotic chromosomes. Therefore drug-induced PCC has opened the way for chromosome analysis not only in metaphase chromosomes but also in interphase chromatin. The drug-induced PCC has thus proven the usefulness in cytogenetics and other cell biology fields. For this second edition version, updated modifications/changes are supplemented in Subheadings 2, 3, and 4, and a new section describing the application of PCC in chromosome science fields is added with citation of updated references.

  20. Human oocyte chromosome analyses need a standardized ...

    Indian Academy of Sciences (India)

    Studies of DNA polymorphisms in human trisomic abor- tions and liveborn have ... Keywords. human oocyte chromosomes; cytogenetic analysis; aneuploidy; nondisjunction; predivision. Journal of .... oocytes and giant embryos. Hum. Reprod.

  1. Conservation of sex chromosomes in lacertid lizards

    Czech Academy of Sciences Publication Activity Database

    Rovatsos, M.; Vukič, J.; Altmanová, M.; Johnson Pokorná, Martina; Moravec, J.; Kratochvíl, L.

    2016-01-01

    Roč. 25, č. 13 (2016), s. 3120-3126 ISSN 0962-1083 Institutional support: RVO:67985904 Keywords : lizards * molecular sex ing * reptiles * sex chromosomes Subject RIV: EG - Zoology Impact factor: 6.086, year: 2016

  2. Micro-Raman spectroscopy of chromosomes

    NARCIS (Netherlands)

    de Mul, F.F.M.; van Welle, A.G.M.; Otto, Cornelis; Greve, Jan

    1984-01-01

    Raman spectra of intact chromosomes (Chinese hamster), recorded with a microspectrometer, are reported. The spectra could be assigned to protein and DNA contributions. Protein and DNA conformations and the ratio of base pairs in DNA were determined.

  3. Partial Duplication of Chromosome 8p

    African Journals Online (AJOL)

    rme

    The partial chromosome 8p duplication is a rare syndrome and is ... abnormality of maternal origin that ... second trimester by vaginal bleeding and ... echocardiography, brain CT scan and. MRI. Fig. 1:Conventional karyotype of case 3 showing.

  4. Chromosomal contact permits transcription between coregulated genes

    CSIR Research Space (South Africa)

    Fanucchi, Stephanie

    2013-10-01

    Full Text Available . To ask whether chromosomal contacts are required for cotranscription in multigene complexes, we devised a strategy using TALENs to cleave and disrupt gene loops in a well-characterized multigene complex. Monitoring this disruption using RNA FISH...

  5. Evaluation of chromosomal abnormalities and common trombophilic ...

    African Journals Online (AJOL)

    2014-03-01

    Mar 1, 2014 ... Infections, genetic, endocrine, anatomic and immunologic problems have been suggested as causes for RM. ... Metaphase chromosome preparations from the .... The rate of karyotypically abnormal abortion specimens.

  6. Histone modifications: Cycling with chromosomal replication

    DEFF Research Database (Denmark)

    Thon, Genevieve

    2008-01-01

    Histone modifications tend to be lost during chromosome duplication. Several recent studies suggest that the RNA interference pathway becomes active during the weakened transcriptional repression occurring at centromeres in S phase, resulting in the re-establishment of histone modifications...

  7. Complement activation in chromosome 13 dementias

    DEFF Research Database (Denmark)

    Rostagno, A.; Revesz, T.; Lashley, T.

    2002-01-01

    Chromosome 13 dementias, familial British dementia (FBD) and familial Danish dementia (FDD), are associated with neurodegeneration and cerebrovascular amyloidosis, with striking neuropathological similarities to Alzheimer's disease (AD). Despite the structural differences among the amyloid subunits...

  8. Non-disjunction of chromosome 13

    DEFF Research Database (Denmark)

    Bugge, Merete; Collins, Andrew; Hertz, Jens Michael

    2007-01-01

    We performed a molecular study with 21 microsatellites on a sample of 82 trisomy 13 conceptuses, the largest number of cases studied to date. The parental origin was determined in every case and in 89% the extra chromosome 13 was of maternal origin with an almost equal number of maternal MI and MII...... recombination in both maternal MI and MII errors and the former is associated with a significant number of tetrads (33%) that are nullichiasmate, which do not appear to be a feature of normal chromosome 13 meiosis. This study supports the evidence for subtle chromosome-specific influences on the mechanisms...... that determine non-disjunction of human chromosomes, consistent with the diversity of findings for other trisomies. Udgivelsesdato: 2007-Aug-15...

  9. System for the analysis of plant chromosomes

    International Nuclear Information System (INIS)

    Medina Martin, D.; Peraza Gonzalez, L.H.

    1996-01-01

    The paper describes a computer system for the automation workers of recognition analysis and interpretation of plant chromosomes. This system permit to carry out the analysis in a more comfortable and faster way, using the image processing techniques

  10. Errata :Chromosomal Abnormalities in Couples with Recurrent ...

    African Journals Online (AJOL)

    Chromosomal Abnormalities in Couples with Recurrent Abortions in Lagos, Nigeria. Akinde OR, Daramola A O, Taiwo I A, Afolayan M O and Akinsola Af. Sonographic Mammary Gland Density Pattern in Women in Selected ommunities of Southern Nigeria.

  11. Viral inactivation in hemotherapy: systematic review on inactivators with action on nucleic acids

    Directory of Open Access Journals (Sweden)

    Patricia Marial Sobral

    2012-01-01

    Full Text Available The aim of this study was to conduct a systematic review on the photoinactivators used in hemotherapy, with action on viral genomes. The SciELO, Science Direct, PubMed and Lilacs databases were searched for articles. The inclusion criterion was that these should be articles on inactivators with action on genetic material that had been published between 2000 and 2010. The key words used in identifying such articles were "hemovigilance", "viral inactivation", "photodynamics", "chemoprevention" and "transfusion safety". Twenty-four articles on viral photoinactivation were found with the main photoinactivators covered being: methylene blue, amotosalen HCl, S-303 frangible anchor linker effector (FRALE, riboflavin and inactin. The results showed that methylene blue has currently been studied least, because it diminishes coagulation factors and fibrinogen. Riboflavin has been studied most because it is a photoinactivator of endogenous origin and has few collateral effects. Amotosalen HCl is effective for platelets and is also used on plasma, but may cause changes both to plasma and to platelets, although these are not significant for hemostasis. S-303 FRALE may lead to neoantigens in erythrocytes and is less indicated for red-cell treatment; in such cases, PEN 110 is recommended. Thus, none of the methods for pathogen reduction is effective for all classes of agents and for all blood components, but despite the high cost, these photoinactivators may diminish the risk of blood-transmitted diseases.

  12. De novo prediction of human chromosome structures: Epigenetic marking patterns encode genome architecture.

    Science.gov (United States)

    Di Pierro, Michele; Cheng, Ryan R; Lieberman Aiden, Erez; Wolynes, Peter G; Onuchic, José N

    2017-11-14

    Inside the cell nucleus, genomes fold into organized structures that are characteristic of cell type. Here, we show that this chromatin architecture can be predicted de novo using epigenetic data derived from chromatin immunoprecipitation-sequencing (ChIP-Seq). We exploit the idea that chromosomes encode a 1D sequence of chromatin structural types. Interactions between these chromatin types determine the 3D structural ensemble of chromosomes through a process similar to phase separation. First, a neural network is used to infer the relation between the epigenetic marks present at a locus, as assayed by ChIP-Seq, and the genomic compartment in which those loci reside, as measured by DNA-DNA proximity ligation (Hi-C). Next, types inferred from this neural network are used as an input to an energy landscape model for chromatin organization [Minimal Chromatin Model (MiChroM)] to generate an ensemble of 3D chromosome conformations at a resolution of 50 kilobases (kb). After training the model, dubbed Maximum Entropy Genomic Annotation from Biomarkers Associated to Structural Ensembles (MEGABASE), on odd-numbered chromosomes, we predict the sequences of chromatin types and the subsequent 3D conformational ensembles for the even chromosomes. We validate these structural ensembles by using ChIP-Seq tracks alone to predict Hi-C maps, as well as distances measured using 3D fluorescence in situ hybridization (FISH) experiments. Both sets of experiments support the hypothesis of phase separation being the driving process behind compartmentalization. These findings strongly suggest that epigenetic marking patterns encode sufficient information to determine the global architecture of chromosomes and that de novo structure prediction for whole genomes may be increasingly possible. Copyright © 2017 the Author(s). Published by PNAS.

  13. Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae)

    Science.gov (United States)

    Suárez, Pablo; Boeris, Juan M.; Blasco-Zúñiga, Ailin; Barbero, Gastón; Gomes, Anderson; Gazoni, Thiago; Costa, William; Nagamachi, Cleusa Y.; Rivera, Miryan; Parise-Maltempi, Patricia P.; Wiley, John E.; Pieczarka, Julio C.; Haddad, Celio F. B.; Faivovich, Julián; Baldo, Diego

    2018-01-01

    The hylid tribe Cophomantini is a diverse clade of Neotropical treefrogs composed of the genera Aplastodiscus, Boana, Bokermannohyla, Hyloscirtus, and Myersiohyla. The phylogenetic relationships of Cophomantini have been comprehensively reviewed in the literature, providing a suitable framework for the study of chromosome evolution. Employing different banding techniques, we studied the chromosomes of 25 species of Boana and 3 of Hyloscirtus; thus providing, for the first time, data for Hyloscirtus and for 15 species of Boana. Most species showed karyotypes with 2n = 2x = 24 chromosomes; some species of the B. albopunctata group have 2n = 2x = 22, and H. alytolylax has 2n = 2x = 20. Karyotypes are all bi-armed in most species presented, with the exception of H. larinopygion (FN = 46) and H. alytolylax (FN = 38), with karyotypes that have a single pair of small telocentric chromosomes. In most species of Boana, NORs are observed in a single pair of chromosomes, mostly in the small chromosomes, although in some species of the B. albopunctata, B. pulchella, and B. semilineata groups, this marker occurs on the larger pairs 8, 1, and 7, respectively. In Hyloscirtus, NOR position differs in the three studied species: H. alytolylax (4p), H. palmeri (4q), and H. larinopygion (1p). Heterochromatin is a variable marker that could provide valuable evidence, but it would be necesserary to understand the molecular composition of the C-bands that are observed in different species in order to test its putative homology. In H. alytolylax, a centromeric DAPI+ band was observed on one homologue of chromosome pair 2. The band was present in males but absent in females, providing evidence for an XX/XY sex determining system in this species. We review and discuss the importance of the different chromosome markers (NOR position, C-bands, and DAPI/CMA3 patterns) for their impact on the taxonomy and karyotype evolution in Cophomantini. PMID:29444174

  14. Human Chromosome 7: DNA Sequence and Biology

    OpenAIRE

    Scherer, Stephen W.; Cheung, Joseph; MacDonald, Jeffrey R.; Osborne, Lucy R.; Nakabayashi, Kazuhiko; Herbrick, Jo-Anne; Carson, Andrew R.; Parker-Katiraee, Layla; Skaug, Jennifer; Khaja, Razi; Zhang, Junjun; Hudek, Alexander K.; Li, Martin; Haddad, May; Duggan, Gavin E.

    2003-01-01

    DNA sequence and annotation of the entire human chromosome 7, encompassing nearly 158 million nucleotides of DNA and 1917 gene structures, are presented. To generate a higher order description, additional structural features such as imprinted genes, fragile sites, and segmental duplications were integrated at the level of the DNA sequence with medical genetic data, including 440 chromosome rearrangement breakpoints associated with disease. This approach enabled the discovery of candidate gene...

  15. Chromosomal organization and segregation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Isabelle Vallet-Gely

    2013-05-01

    Full Text Available The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed.

  16. Abnormal sex chromosome constitution and longitudinal growth

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Skakkebaek, Niels E; Juul, Anders

    2008-01-01

    Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles.......Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles....

  17. Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae.

    Directory of Open Access Journals (Sweden)

    Juan M Ferro

    Full Text Available The hylid tribe Cophomantini is a diverse clade of Neotropical treefrogs composed of the genera Aplastodiscus, Boana, Bokermannohyla, Hyloscirtus, and Myersiohyla. The phylogenetic relationships of Cophomantini have been comprehensively reviewed in the literature, providing a suitable framework for the study of chromosome evolution. Employing different banding techniques, we studied the chromosomes of 25 species of Boana and 3 of Hyloscirtus; thus providing, for the first time, data for Hyloscirtus and for 15 species of Boana. Most species showed karyotypes with 2n = 2x = 24 chromosomes; some species of the B. albopunctata group have 2n = 2x = 22, and H. alytolylax has 2n = 2x = 20. Karyotypes are all bi-armed in most species presented, with the exception of H. larinopygion (FN = 46 and H. alytolylax (FN = 38, with karyotypes that have a single pair of small telocentric chromosomes. In most species of Boana, NORs are observed in a single pair of chromosomes, mostly in the small chromosomes, although in some species of the B. albopunctata, B. pulchella, and B. semilineata groups, this marker occurs on the larger pairs 8, 1, and 7, respectively. In Hyloscirtus, NOR position differs in the three studied species: H. alytolylax (4p, H. palmeri (4q, and H. larinopygion (1p. Heterochromatin is a variable marker that could provide valuable evidence, but it would be necesserary to understand the molecular composition of the C-bands that are observed in different species in order to test its putative homology. In H. alytolylax, a centromeric DAPI+ band was observed on one homologue of chromosome pair 2. The band was present in males but absent in females, providing evidence for an XX/XY sex determining system in this species. We review and discuss the importance of the different chromosome markers (NOR position, C-bands, and DAPI/CMA3 patterns for their impact on the taxonomy and karyotype evolution in Cophomantini.

  18. Interphase Chromosome Profiling: A Method for Conventional Banded Chromosome Analysis Using Interphase Nuclei.

    Science.gov (United States)

    Babu, Ramesh; Van Dyke, Daniel L; Dev, Vaithilingam G; Koduru, Prasad; Rao, Nagesh; Mitter, Navnit S; Liu, Mingya; Fuentes, Ernesto; Fuentes, Sarah; Papa, Stephen

    2018-02-01

    - Chromosome analysis on bone marrow or peripheral blood samples fails in a small proportion of attempts. A method that is more reliable, with similar or better resolution, would be a welcome addition to the armamentarium of the cytogenetics laboratory. - To develop a method similar to banded metaphase chromosome analysis that relies only on interphase nuclei. - To label multiple targets in an equidistant fashion along the entire length of each chromosome, including landmark subtelomere and centromere regions. Each label so generated by using cloned bacterial artificial chromosome probes is molecularly distinct with unique spectral characteristics, so the number and position of the labels can be tracked to identify chromosome abnormalities. - Interphase chromosome profiling (ICP) demonstrated results similar to conventional chromosome analysis and fluorescence in situ hybridization in 55 previously studied cases and obtained useful ICP chromosome analysis results on another 29 cases in which conventional methods failed. - ICP is a new and powerful method to karyotype peripheral blood and bone marrow aspirate preparations without reliance on metaphase chromosome preparations. It will be of particular value for cases with a failed conventional analysis or when a fast turnaround time is required.

  19. Paternal isodisomy of chromosome 6 in association with a maternal supernumerary marker chromosome (6)

    Energy Technology Data Exchange (ETDEWEB)

    James, R.S.; Crolla, J.A.; Sitch, F.L. [Salisbury District Hospital, Wiltshire (United Kingdom)] [and others

    1994-09-01

    Uniparental disomy may arise by a number of different mechanisms of aneuploidy correction. A population that has been identified as being at increased risk of aneuploidy are those individuals bearing supernumerary marker chromosomes (SMCs). There have been a number of cases reported of trisomy 21 in association with bi-satellited marker chromosomes have described two individuals with small inv dup (15) markers. One had paternal isodisomy of chromosome 15 and Angelman syndrome. The other had maternal heterodisomy (15) and Prader-Willi syndrome. At the Wessex Regional Genetics Laboratory we have conducted a search for uniparental disomy of the normal homologues of the chromosomes from which SMCs originated. Our study population consists of 39 probands with SMCs originating from a number of different autosomes, including 17 with SMCs of chromosome 15 origin. Using PCR amplification of microsatellite repeat sequences located distal to the regions included in the SMCs we have determined the parental origin of the two normal homologues in each case. We have identified paternal isodisomy of chromosome 6 in a female child with a supernumerary marker ring chromosome 6 in approximately 70% of peripheral blood lymphocytes. The marker was found to be of maternal origin. This is the second case of paternal isodisomy of chromosome 6 to be reported, and the first in association with a SMC resulting in a partial trisomy for a portion of the short arm of chromosome 6. In spite of this, the patient appears to be functioning appropriately for her age.

  20. Chromosomes in the genesis and progression of ependymomas

    DEFF Research Database (Denmark)

    Rogatto, S R; Casartelli, C; Rainho, C A

    1993-01-01

    chromosomes in three cases. Structural rearrangements of chromosome 2 were a finding for all cases and involved loss of material at 2q32-34. Other structural chromosome abnormalities detected involved chromosomes 4, 6, 10, 11, 12, and X. We also reviewed data on 22 cases previously reported....

  1. Inactivation of an enterovirus by airborne disinfectants

    Science.gov (United States)

    2013-01-01

    Background The activity of airborne disinfectants on bacteria, fungi and spores has been reported. However, the issue of the virucidal effect of disinfectants spread by fogging has not been studied thoroughly. Methods A procedure has been developed to determine the virucidal activity of peracetic acid-based airborne disinfectants on a resistant non-enveloped virus poliovirus type 1. This virus was laid on a stainless carrier. The products were spread into the room by hot fogging at 55°C for 30 minutes at a concentration of 7.5 mL.m-3. Poliovirus inoculum, supplemented with 5%, heat inactivated non fat dry organic milk, were applied into the middle of the stainless steel disc and were dried under the air flow of a class II biological safety cabinet at room temperature. The Viral preparations were recovered by using flocked swabs and were titered on Vero cells using the classical Spearman-Kärber CPE reading method, the results were expressed as TCID50.ml-1. Results The infectious titer of dried poliovirus inocula was kept at 105 TCID50.mL-1 up to 150 minutes at room temperature. Dried inocula exposed to airborne peracetic acid containing disinfectants were recovered at 60 and 120 minutes post-exposition and suspended in culture medium again. The cytotoxicity of disinfectant containing medium was eliminated through gel filtration columns. A 4 log reduction of infectious titer of dried poliovirus inocula exposed to peracetic-based airborne disinfectant was obtained. Conclusion This study demonstrates that the virucidal activity of airborne disinfectants can be tested on dried poliovirus. PMID:23587047

  2. Antimicrobial blue light inactivation of Neisseria gonorrhoeae

    Science.gov (United States)

    Wang, Ying; Gu, Ying; Dai, Tianhong

    2018-02-01

    Neisseria gonorrhoeae is a human-adapted, gram-negative diplococcus that infects human reproductive tracts and causes gonorrhea, a sexually transmitted disease, resulting in discharge and inflammation at the urethra, cervix, pharynx, or rectum. Over the years, N. gonorrhoeae has developed resistance to nearly every drug ever used to treat it, including sulfonamides, penicillin, tetracycline, and fluoroquinolones. Drug-resistant N. gonorrhoeae is now considered by the Centers for Disease Control and Prevention (CDC) as an urgent threat. The present study aimed to evaluate the efficacy of antimicrobial blue light (aBL) at 405 and 470 nm for inactivating N. gonorrhoeae and reveal the mechanism of action. Our results showed that an exposure of 45 J/cm2 aBL at 405 nm reduced the bacterial CFU by 7.16-log10. When the aBL exposure was increased to 54 J/cm2, eradication of bacterial CFU was achieved. When the bacteria were exposed to aBL at 470 nm, 3-log10 reduction of CFU was observed at an aBL exposure of higher than 126 J/cm2. Absorption and fluorescence spectroscopic analyses revealed the presence of endogenous porphyrins and flavins in N. gonorrhoeae cells. The present study indicated that aBL is a potential strategy to control N. gonorrhoeae infections. Endogenous porphyrins play a vital role in the killing effects of aBL. In vivo experiments are ongoing in our laboratory to treat genital tract infections in mice using aBL and explore the potential clinical applications.

  3. Thermal inactivation of Phytophthora capsici oospores.

    Science.gov (United States)

    Etxeberria, Aitzol; Mendarte, Sorkunde; Larregla, Santiago

    2011-01-01

    Phytophthora capsici is a major fungal plant pathogen that causes root and crown rot of pepper crops and its oospores are the most resistant propagules. To evaluate the effect of different temperature regimes and exposure times on the survival of P. capsici oospores. Thermal inactivation treatments simulated field conditions, through the use of different constant and cycling temperature regimes, in moistened sterilized soil (15-53 °C) and sterilized water (45-53 °C). The plasmolysis method evaluated oospore viability. Relationships between oospores viability and exposure time were statistically determined by linear regression. Interpolation was used to calculate the estimated times required to kill a determined percentage of the population. The required time to reduce P. capsici oospores viability decreased with increasing temperatures. Times required to kill 100% of oospores were 199-22-6.6-4.7-1.0 hours at 40-45-47.5-50-53°C respectively in moistened soil and 31-1.0-0.2 hours at 45-50-53 °C in water. Oospores were scarcely affected at temperatures ≤ 35 °C. With 1,680 hours at 15-35 °C, oospores survival in soil ranged from 88 to 36%. The 4 hours-40 °C regime killed 100% of oospores after 28days, while the 5 hours-35°C regime after 70 days killed only 75%. Time required to achieve total oospores death was remarkably shortened in water when compared with moistened soil. The developed models can be used to predict survival values at any exposure time with constant temperatures ranging from 40 to 53 °C in moistened soil and from 45 to 53 °C in water. The weakening of P. capsici oospores under sublethal heating, is a useful observation that can be applied for pathogen control with solarization. Copyright © 2010 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  4. Dimensions of driving anger and their relationships with aberrant driving.

    Science.gov (United States)

    Zhang, Tingru; Chan, Alan H S; Zhang, Wei

    2015-08-01

    The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Hda inactivation of DnaA is the predominant mechanism preventing hyperinitiation of Escherichia coli DNA replication.

    Science.gov (United States)

    Camara, Johanna E; Breier, Adam M; Brendler, Therese; Austin, Stuart; Cozzarelli, Nicholas R; Crooke, Elliott

    2005-08-01

    Initiation of DNA replication from the Escherichia coli chromosomal origin is highly regulated, assuring that replication occurs precisely once per cell cycle. Three mechanisms for regulation of replication initiation have been proposed: titration of free DnaA initiator protein by the datA locus, sequestration of newly replicated origins by SeqA protein and regulatory inactivation of DnaA (RIDA), in which active ATP-DnaA is converted to the inactive ADP-bound form. DNA microarray analyses showed that the level of initiation in rapidly growing cells that lack datA was indistinguishable from that in wild-type cells, and that the absence of SeqA protein caused only a modest increase in initiation, in agreement with flow-cytometry data. In contrast, cells lacking Hda overinitiated replication twofold, implicating RIDA as the predominant mechanism preventing extra initiation events in a cell cycle.

  6. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1981-01-01

    Purpose: To ensure the scram operation of a control rod by the reliable detection for the position of control rods. Constitution: A permanent magnet is provided to the lower portion of a connecting rod in engagement with a control rod and a tube having a plurality of lead switches arranged axially therein in a predetermined pitch is disposed outside of the control rod drives. When the control rod moves upwardly in the scram operation, the lead switches are closed successively upon passage of the permanent magnet to operate the electrical circuit provided by way of each of the lead switches. Thus, the position for the control rod during the scram can reliably be determined and the scram characteristic of the control rod can be recognized. (Furukawa, Y.)

  7. [Epilepsy and driving].

    Science.gov (United States)

    Matsuura, Masato

    2014-05-01

    In Japan, the Road Traffic Act was amended in June 2013, including new penalty to false statement in a disease condition declaration form, and new voluntary notification system for a doctor who is aware that a person is at high risk for traffic accident and in possession of a driver license. Moreover, New Criminal Law Act was established in November 2013, including a prison sentence of up to 15 years for persons, who under the influence of specific drugs or diseases, causing death or injury to other persons by driving a motor vehicle. Both laws are supposed to be enforced during 2014, after additional resolutions including the review of the laws after five years, considerations so as not to create discrimination due to diseases, etc are examined.

  8. Control rod drives

    International Nuclear Information System (INIS)

    Furumitsu, Yutaka.

    1981-01-01

    Purpose: To improve the reliability of a device for driving an LMFBR type reactor control rod by providing a buffer unit having a stationary electromagnetic coil and a movable electromagnetic coil in the device to thereby avord impact stress at scram time and to simplify the structure of the buffer unit. Constitution: A non-contact type buffer unit is constructed with a stationary electromagnetic coil, a cable for the stationary coil, a movable electromagnetic coil, a spring cable for the movable coil, and a backup coil spring or the like. Force produced at scram time is delivered without impact by the attracting or repelling force between the stationary coil and the movable coil of the buffer unit. Accordingly, since the buffer unit is of a non-contact type, there is no mechanical impact and thus no large impact stress, and as it has simple configuration, the reliability is improved and the maintenance can be conducted more easily. (Yoshihara, H.)

  9. Control rod drives

    International Nuclear Information System (INIS)

    Yamanaka, Toshikatsu.

    1979-01-01

    Purpose: To protect bellows against failures due to negative pressure to prevent the loss of pressure balance caused by the expansion of the bellows upon scram. Constitution: An expansion pipe connected to the control rod drive is driven along a guide pipe to insert a control rod into the reactor core. Expansible bellows are provided at the step between the expansion pipe and the guide pipe. Further, a plurality of bore holes or slits are formed on the side wall of the guide pipe corresponding to the expansion portion of the bellows. In such an arrangement, when the expansion pipe falls rapidly and the bellows are expanded upon scram, the volume between each of the pipes of the bellows and the guide pipe is increased to produce a negative pressure, but the effect of the negative pressure on the bellows can be eliminated by the flowing-in of coolants corresponding to that pressure through the bore holes or the slits. (Furukawa, Y.)

  10. Chromosome abnormalities in atomic bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Tomonaga, Y [Nagasaki Univ. (Japan). School of Medicine

    1976-09-01

    Chromosome abnormalities in bone marrow cells were recognized in 6 cases which consisted of one case of chronic myelogenous leukemia, two cases of acute myelogenous leukemia, one case of sideroblastic anemia, and two cases of myelodysplasis. Frequency of stable type chromosome abnormalities in bone marrow cells was investigated in 45 atomic bomb survivors without hematologic disorders and 15 controls. It was 1.4% (15 cases) in the group exposed to atomic bomb within 1 km from the hypocenter, which was significantly higher as compared with 0.1% (15 cases) in the group exposed to atomic bomb over 2.5 km from the hypocenter and 0.2% in normal controls. Examination of chromosome was also made on 2 of 3 cases which were the seconds born of female with high chromosome abnormality, who was exposed to within 1 km from the hypocenter, and healthy male exposed 3 km from the hypocenter. These two cases showed chromosome of normal male type, and balanced translocation was not recognized. There was not a significant difference in chromosome abnormalities between the seconds of atomic bomb survivors and controls.

  11. Evolutionary stability of sex chromosomes in snakes.

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-12-22

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms. © 2015 The Author(s).

  12. Chromosome aberration assays in barley (Hordeum vulgare)

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, M J [Univ. of Tennessee, Knoxville; Nilan, R A

    1982-01-01

    Barley is an exceellent organism for studies of induced chromosome aberrations because of its few (2n = 2x = 14) relatively large chromosomes. Root-tip and shoot-tip cells have been used extensively for the study of ionizing radiation-induced chromosome aberrations. The general procedures are well known, the technology is simple and easy to learn, and the assays are relatively quick and inexpensive. Both root tips and shoot tips can be used for the study of chemical mutagens as well as ionizing radiations. Pollen mother cells are well suited for studying the effects of mutagens on meiotic chromosomes. The literature review for the Gene-Tox Program reported on 61 chemicals tested for their effects on barley chromosomes. Of these, 90% were reported to be either positive or positive dose-related, while 7% were negative and 3% were questionable. Barley assays based on chromosomal aberrations are useful to detect the clastogenic potency of chemicals under laboratory conditions. Indications are that the data from barley can be used to corroborate data obtained from other organisms. Among the classes of chemicals assayed were: alcohols and phenols; alkaloids; epoxides; alkyl sulfates; amides and sulfonamides; aromatic amines; aryl halides; aziridines; alkenes; carbamates; hydroazides; nitroaromatics; nitrosamides; nitrosources; phenothiazines; and polycyclic aromatic hydrocarbons.

  13. Flow cytogenetics: progress toward chromosomal aberration detection

    International Nuclear Information System (INIS)

    Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

    1977-01-01

    Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

  14. Chromosome abnormalities in atomic bomb survivors

    International Nuclear Information System (INIS)

    Tomonaga, Yu

    1976-01-01

    Chromosome abnormalities in bone marrow cells were recognized in 6 cases which consisted of one case of chronic myelogenous leukemia, two cases of acute myelogenous leukemia, one case of sideroblastic anemia, and two cases of myelodysplasis. Frequency of stable type chromosome abnormalities in bone marrow cells was investigated in 45 atomic bomb survivors without hematologic disorders and 15 controls. It was 1.4% (15 cases) in the group exposed to atomic bomb within 1 km from the hypocenter, which was significantly higher as compared with 0.1% (15 cases) in the group exposed to atomic bomb over 2.5 km from the hypocenter and 0.2% in normal controls. Examination of chromosome was also made on 2 of 3 cases which were the seconds born of female with high chromosome abnormality, who was exposed to within 1 km from the hypocenter, and healthy male exposed 3 km from the hypocenter. These two cases showed chromosome of normal male type, and balanced translocation was not recognized. There was not a significant difference in chromosome abnormalities between the seconds of atomic bomb survivors and controls. (Kanao, N.)

  15. Do emotions drive psychosis?

    Directory of Open Access Journals (Sweden)

    João G. Ribeiro

    2012-12-01

    Full Text Available Introduction: How important is the emotional life of persons who manifest psychotic symptoms? Aims: The aim of this paper is to review evidence on a causal role for emotions in psychotic processes. Methods: Selective review of literature on affective symptoms in psychoses, on emotions in the production of psychotic symptoms and on dopaminergic models of psychosis. Results: Affective symptoms are relevant across psychoses. Persons with schizophrenia have high levels of emotional reactivity and the intensification of negative affects not only is associated with but also precedes the intensification of psychotic symptoms, which is evidence that negative emotions drive the course of psychotic symptoms. Negative self‑representations are central in psychotic processes and can be the link between negative emotions and psychosis. Evidence favours the notion that persecutory delusions are consistent with negative affects and self‑representations, while grandiose delusions are consistent with a defensive amplification of positive affects and self‑representations. Shame has been proposed as the core emotional experience of psychosis, one in which the self becomes vulnerable to the external world, which is consistent with persecutory experiences. Assaults on the self, under the form of hostility in the family environment and society, are strong predictors of relapse and development of schizophrenia. Assaults on the self which induce social defeat are also strong stimulants of mesolimbic dopaminergic pathways, whose hyperactivity is associated with acute psychotic episodes and the experience of “aberrant salience”, put forward as a dopaminergic model of psychosis. Conclusions: The “defeat of the self” emerges as a central link that binds the experience of negative emotions to the expression of psychotic symptoms and its psychological and neurobiological correlates. The hypothesis gains support that the emotions related to that defeat control

  16. Ultra high pressure homogenization (UHPH inactivation of Bacillus amyloliquefaciens spores in phosphate buffered saline (PBS and milk

    Directory of Open Access Journals (Sweden)

    Peng eDong

    2015-07-01

    Full Text Available Ultra high pressure homogenization (UHPH opens up new areas for dynamic high pressure assisted thermal sterilization of liquids. Bacillus amyloliquefaciens spores are resistant to high isostatic pressure and temperature and were suggested as potential surrogate for high pressure thermal sterilization validation. B. amyloliquefaciens spores suspended in PBS buffer (0.01 M, pH 7.0, low fat milk (1.5%, pH 6.7 and whole milk (3.5%, pH 6.7 at initial concentration of ~106 CFU/mL were subjected to UHPH treatments at 200, 300 and 350 MPa with an inlet temperature at ~80 °C. Thermal inactivation kinetics of B. amyloliquefaciens spores in PBS and milk were assessed with thin wall glass capillaries and modeled using mechanistic linear first order and Weibull models. The residence time during UHPH treatments was estimated to determine the contribution of temperature to spore inactivation by UHPH. No sublethal injury was detected after UHPH treatments using sodium chloride as selective component in the nutrient agar medium. The inactivation profiles of spores in PBS buffer and milk were compared and fat provided no clear protective effect for spores against treatments. Treatment at 200 MPa with valve temperatures lower than 125 °C caused no reduction of spores. A reduction of 3.5 log10 CFU/mL of B. amyloliquefaciens spores was achieved by treatment at 350 MPa with a valve temperature higher than 150 °C. The modeled thermal inactivation and observed inactivation during UHPH treatments suggest that temperature could be the main lethal effect driving inactivation.

  17. Polytene chromosome map and inversion polymorphism in Drosophila mediopunctata

    Directory of Open Access Journals (Sweden)

    Galina Ananina

    2002-07-01

    Full Text Available Drosophila mediopunctata belongs to the tripunctata group, and is one of the commonest Drosophila species collected in some places in Brazil, especially in the winter. A standard map of the polytene chromosomes is presented. The breakpoints of the naturally occurring chromosomal rearrangements are marked on the map. The distribution of breaking points through the chromosomes of D. mediopunctata is apparently non-random. Chromosomes X, II and IV show inversion polymorphisms. Chromosome II is the most polymorphic, with 17 inversions, 8 inversions in the distal region and 9 in the proximal region. Chromosome X has four different gene arrangements, while chromosome IV has only two.

  18. DNA adenine methylation is required to replicate both Vibrio cholerae chromosomes once per cell cycle.

    Science.gov (United States)

    Demarre, Gaëlle; Chattoraj, Dhruba K

    2010-05-06

    DNA adenine methylation is widely used to control many DNA transactions, including replication. In Escherichia coli, methylation serves to silence newly synthesized (hemimethylated) sister origins. SeqA, a protein that binds to hemimethylated DNA, mediates the silencing, and this is necessary to restrict replication to once per cell cycle. The methylation, however, is not essential for replication initiation per se but appeared so when the origins (oriI and oriII) of the two Vibrio cholerae chromosomes were used to drive plasmid replication in E. coli. Here we show that, as in the case of E. coli, methylation is not essential for oriI when it drives chromosomal replication and is needed for once-per-cell-cycle replication in a SeqA-dependent fashion. We found that oriII also needs SeqA for once-per-cell-cycle replication and, additionally, full methylation for efficient initiator binding. The requirement for initiator binding might suffice to make methylation an essential function in V. cholerae. The structure of oriII suggests that it originated from a plasmid, but unlike plasmids, oriII makes use of methylation for once-per-cell-cycle replication, the norm for chromosomal but not plasmid replication.

  19. DNA adenine methylation is required to replicate both Vibrio cholerae chromosomes once per cell cycle.

    Directory of Open Access Journals (Sweden)

    Gaëlle Demarre

    2010-05-01

    Full Text Available DNA adenine methylation is widely used to control many DNA transactions, including replication. In Escherichia coli, methylation serves to silence newly synthesized (hemimethylated sister origins. SeqA, a protein that binds to hemimethylated DNA, mediates the silencing, and this is necessary to restrict replication to once per cell cycle. The methylation, however, is not essential for replication initiation per se but appeared so when the origins (oriI and oriII of the two Vibrio cholerae chromosomes were used to drive plasmid replication in E. coli. Here we show that, as in the case of E. coli, methylation is not essential for oriI when it drives chromosomal replication and is needed for once-per-cell-cycle replication in a SeqA-dependent fashion. We found that oriII also needs SeqA for once-per-cell-cycle replication and, additionally, full methylation for efficient initiator binding. The requirement for initiator binding might suffice to make methylation an essential function in V. cholerae. The structure of oriII suggests that it originated from a plasmid, but unlike plasmids, oriII makes use of methylation for once-per-cell-cycle replication, the norm for chromosomal but not plasmid replication.

  20. Inactivated probiotic Bacillus coagulans GBI-30 induces complex immune activating, anti-inflammatory, and regenerative markers in vitro

    Directory of Open Access Journals (Sweden)

    Jensen GS

    2017-08-01

    Full Text Available Gitte S Jensen,1 Howard A Cash,2 Sean Farmer,2 David Keller2 1NIS Labs, Esplanade, Klamath Falls, OR, USA, 2Ganeden Biotech Inc., Landerbrook Drive Suite, Mayfield Heights, OH, USA Objective: The aim of this study was to document the immune activating and anti-inflammatory effects of inactivated probiotic Bacillus coagulans GBI-30, 6086 (Staimune™ cells on human immune cells in vitro.Methods: In vitro cultures of human peripheral blood mononuclear cells (PBMC from healthy blood donors were treated with inactivated B. coagulans GBI-30, 6086 cells for 24 hours. After incubation, the PBMC were stained with fluorochrome-labeled monoclonal antibodies for CD3, CD56, and CD69 to monitor cellular activation by flow cytometry. The culture supernatants were tested for cytokine profile using a 27-plex Luminex array, including pro- and anti-inflammatory cytokines, chemokines, and growth factors.Results: Inactivated B. coagulans GBI-30, 6086 cells induced the CD69 early activation marker on CD3+ CD56− T lymphocytes, CD3+ CD56+ NKT cells, CD3−CD56+ NK cells, and also some cells within the CD3−CD56− non-T non-NK cell subset. Culture supernatants showed robust increases in the immune-activating cytokines IL-1β, IL-6, IL-17A, and TNF-α. IFN-γ levels were increased, along with three chemokines, MCP-1, MIP-1α, and MIP-1β. The two anti-inflammatory cytokines IL-1ra and IL-10 showed increases, as well as the G-CSF growth factor involved in repair and stem cell biology. In contrast, GM-CSF levels showed a mild decrease, showing a highly selective growth factor response.Conclusion: The inactivated B. coagulans GBI-30, 6086 cells activated human immune cells and altered the production of both immune activating and anti-inflammatory cytokines and chemokines. Of special importance is the novel demonstration of a selective upregulation of the G-CSF growth factor involved in postinjury and postinflammation repair and regeneration. This suggests that