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Sample records for chromosomal fragile sites

  1. Identification and Investigation of Native Chromosomal Fragile Sites in the Avian Cell Line DT40

    DEFF Research Database (Denmark)

    Pentzold, Constanze

    Chromosomal fragile sites are a cytogenetic phenomenon of genome instability that manifests in gaps or breaks on metaphase chromosomes. Diverse mechanisms are involved in their expression but all of them originate from the idea of replication impairment as the main driver for fragility. Cellular ...... kingdom....

  2. Chromatin Folding, Fragile Sites, and Chromosome Aberrations Induced by Low- and High- LET Radiation

    Science.gov (United States)

    Zhang, Ye; Cox, Bradley; Asaithamby, Aroumougame; Chen, David J.; Wu, Honglu

    2013-01-01

    We previously demonstrated non-random distributions of breaks involved in chromosome aberrations induced by low- and high-LET radiation. To investigate the factors contributing to the break point distribution in radiation-induced chromosome aberrations, human epithelial cells were fixed in G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome in separate colors. After the images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multimega base pair scale. Specific locations of the chromosome, in interphase, were also analyzed with bacterial artificial chromosome (BAC) probes. Both mBAND and BAC studies revealed non-random folding of chromatin in interphase, and suggested association of interphase chromatin folding to the radiation-induced chromosome aberration hotspots. We further investigated the distribution of genes, as well as the distribution of breaks found in tumor cells. Comparisons of these distributions to the radiation hotspots showed that some of the radiation hotspots coincide with the frequent breaks found in solid tumors and with the fragile sites for other environmental toxins. Our results suggest that multiple factors, including the chromatin structure and the gene distribution, can contribute to radiation-induced chromosome aberrations.

  3. 45S rDNA regions are chromosome fragile sites expressed as gaps in vitro on metaphase chromosomes of root-tip meristematic cells in Lolium spp.

    Directory of Open Access Journals (Sweden)

    Jing Huang

    Full Text Available BACKGROUND: In humans, chromosome fragile sites are regions that are especially prone to forming non-staining gaps, constrictions or breaks in one or both of the chromatids on metaphase chromosomes either spontaneously or following partial inhibition of DNA synthesis and have been well identified. So far, no plant chromosome fragile sites similar to those in human chromosomes have been reported. METHODS AND RESULTS: During the course of cytological mapping of rDNA on ryegrass chromosomes, we found that the number of chromosomes plus chromosome fragments was often more than the expected 14 in most cells for Lolium perenne L. cv. Player by close cytological examination using a routine chromosome preparation procedure. Further fluorescent in situ hybridization (FISH using 45S rDNA as a probe indicated that the root-tip cells having more than a 14-chromosome plus chromosome fragment count were a result of chromosome breakage or gap formation in vitro (referred to as chromosome lesions at 45S rDNA sites, and 86% of the cells exhibited chromosome breaks or gaps and all occurred at the sites of 45S rDNA in Lolium perenne L. cv. Player, as well as in L. multiflorum Lam. cv. Top One. Chromatin depletion or decondensation occurred at various locations within the 45S rDNA regions, suggesting heterogeneity of lesions of 45S rDNA sites with respect to their position within the rDNA region. CONCLUSIONS: The chromosome lesions observed in this study are very similar cytologically to that of fragile sites observed in human chromosomes, and thus we conclude that the high frequency of chromosome lesions in vitro in Lolium species is the result of the expression of 45S rDNA fragile sites. Possible causes for the spontaneous expression of fragile sites and their potential biological significance are discussed.

  4. Characterization of FRA7B, a human common fragile site mapped at the 7p chromosome terminal region.

    Science.gov (United States)

    Bosco, Nazario; Pelliccia, Franca; Rocchi, Angela

    2010-10-01

    Common fragile sites (CFS) are specific regions of the mammalian chromosomes that are particularly prone to gaps and breaks. They are a cause of genome instability, and the location of many CFS correlates with breakpoints of aberrations recurrent in some cancers. The molecular characterization of some CFS has not clarified the causes of their fragility. In this work, by using fluorescence in situ hybridization analysis with BAC and PAC clones, we determined the DNA sequence of the CFS FRA7B. The FRA7B sequence was then analyzed to identify coding sequences and some structural features possibly involved in fragility. FRA7B spans about 12.2 megabases, and is therefore one of the largest CFS analyzed. It maps at the 7p21.3-22.3 chromosome bands, therefore at the interface of G- and R-band regions that are probably difficult to replicate. A 90-kilobase long sequence that presents very high flexibility values was identified at the very beginning of the more fragile CFS region. Three large genes (THSD7A, SDK1, and MAD1L1) and two miRNA genes (MIRN589 and MIRN339) map in the fragile region. The chromosome band 7p22 is a recurrent breakpoint in chromosome abnormalities in different types of neoplasm. FRA7B is the first characterized CFS located in a chromosome terminal region.

  5. Over half of breakpoints in gene pairs involved in cancer-specific recurrent translocations are mapped to human chromosomal fragile sites

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    Pierce Levi CT

    2009-01-01

    Full Text Available Abstract Background Gene rearrangements such as chromosomal translocations have been shown to contribute to cancer development. Human chromosomal fragile sites are regions of the genome especially prone to breakage, and have been implicated in various chromosome abnormalities found in cancer. However, there has been no comprehensive and quantitative examination of the location of fragile sites in relation to all chromosomal aberrations. Results Using up-to-date databases containing all cancer-specific recurrent translocations, we have examined 444 unique pairs of genes involved in these translocations to determine the correlation of translocation breakpoints and fragile sites in the gene pairs. We found that over half (52% of translocation breakpoints in at least one gene of these gene pairs are mapped to fragile sites. Among these, we examined the DNA sequences within and flanking three randomly selected pairs of translocation-prone genes, and found that they exhibit characteristic features of fragile DNA, with frequent AT-rich flexibility islands and the potential of forming highly stable secondary structures. Conclusion Our study is the first to examine gene pairs involved in all recurrent chromosomal translocations observed in tumor cells, and to correlate the location of more than half of breakpoints to positions of known fragile sites. These results provide strong evidence to support a causative role for fragile sites in the generation of cancer-specific chromosomal rearrangements.

  6. The human chromosomal fragile sites more often involved in constitutional deletions and duplications - A genetic and statistical assessment

    Science.gov (United States)

    Gomes, Dora Prata; Sequeira, Inês J.; Figueiredo, Carlos; Rueff, José; Brás, Aldina

    2016-12-01

    Human chromosomal fragile sites (CFSs) are heritable loci or regions of the human chromosomes prone to exhibit gaps, breaks and rearrangements. Determining the frequency of deletions and duplications in CFSs may contribute to explain the occurrence of human disease due to those rearrangements. In this study we analyzed the frequency of deletions and duplications in each human CFS. Statistical methods, namely data display, descriptive statistics and linear regression analysis were applied to analyze this dataset. We found that FRA15C, FRA16A and FRAXB are the most frequently involved CFSs in deletions and duplications occurring in the human genome.

  7. 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.

  8. MUS81 promotes common fragile site expression

    DEFF Research Database (Denmark)

    Ying, Songmin; Minocherhomji, Sheroy; Chan, Kok Lung

    2013-01-01

    Fragile sites are chromosomal loci with a propensity to form gaps or breaks during early mitosis, and their instability is implicated as being causative in certain neurological disorders and cancers. Recent work has demonstrated that the so-called common fragile sites (CFSs) often impair the fait......Fragile sites are chromosomal loci with a propensity to form gaps or breaks during early mitosis, and their instability is implicated as being causative in certain neurological disorders and cancers. Recent work has demonstrated that the so-called common fragile sites (CFSs) often impair...... the faithful disjunction of sister chromatids in mitosis. However, the mechanisms by which CFSs express their fragility, and the cellular factors required to suppress CFS instability, remain largely undefined. Here, we report that the DNA structure-specific nuclease MUS81-EME1 localizes to CFS loci in early...

  9. 精神发育迟滞者与染色体脆性部位相关性的研究%The study on correlativity between mental retardation and chromosome fragile site

    Institute of Scientific and Technical Information of China (English)

    高文和

    2001-01-01

    Objective: To explore the correlatitiy between mental retardation, chromosome aberrtion rate and fragile site expression rate. Methods: Using the peripheral blood lymphocyte chromosome preparation technique and fragile site technique, to analyze chromosome aberrtion rate and fragile site expression rate of 30 cases of mental retardation sufferer and 30 cases of normal person respectively. Results: About the mental retardation sufferer, the chromosome aberration rate is 4.32% ;the fragile site expression rate is 2.18%. About the control group, the chromosome aberration rate of is 1.55%; the fragile site expression rate is 0.89% .Both the chromosome aberration rate and the fragile site expression rate of two groups are distinct from each other(P<0.01). Conclusion: The mental retardation is correlative with the chromosome aberration and the fragile site expression rate.%目的:探讨精神发育迟滞者与染色体畸变率和脆性部位表达率的相关性。方法:采用外周血淋巴细胞染色[摘要]目的:探讨精神发育迟滞者与染色体畸变率和脆性部位表达率的相关性。方法:采用外周血淋巴细胞染色体制备和脆性技术,对30例精神发育迟滞者和30例正常人的染色体畸变率和脆性部位表达率进行分析。结果:精神发育迟滞者染色体的畸变率为4.32%,脆性部位的表达率为2.18%,而正常对照组染色体畸变率为1.55%,脆性部位的表达率为0.89%,两者的染色体畸变率和脆性部位表达率有明显的差异(P<0.01)。结论:提示精神发育迟滞与染色体的畸变率和脆性部位的表达率有一定的相关性。

  10. Common chromosomal fragile sites (CFS) may be involved in normal and traumatic cognitive stress memory consolidation and altered nervous system immunity.

    Science.gov (United States)

    Gericke, G S

    2010-05-01

    Previous reports of specific patterns of increased fragility at common chromosomal fragile sites (CFS) found in association with certain neurobehavioural disorders did not attract attention at the time due to a shift towards molecular approaches to delineate neuropsychiatric disorder candidate genes. Links with miRNA, altered methylation and the origin of copy number variation indicate that CFS region characteristics may be part of chromatinomic mechanisms that are increasingly linked with neuroplasticity and memory. Current reports of large-scale double-stranded DNA breaks in differentiating neurons and evidence of ongoing DNA demethylation of specific gene promoters in adult hippocampus may shed new light on the dynamic epigenetic changes that are increasingly appreciated as contributing to long-term memory consolidation. The expression of immune recombination activating genes in key stress-induced memory regions suggests the adoption by the brain of this ancient pattern recognition and memory system to establish a structural basis for long-term memory through controlled chromosomal breakage at highly specific genomic regions. It is furthermore considered that these mechanisms for management of epigenetic information related to stress memory could be linked, in some instances, with the transfer of the somatically acquired information to the germline. Here, rearranged sequences can be subjected to further selection and possible eventual retrotranscription to become part of the more stable coding machinery if proven to be crucial for survival and reproduction. While linkage of cognitive memory with stress and fear circuitry and memory establishment through structural DNA modification is proposed as a normal process, inappropriate activation of immune-like genomic rearrangement processes through traumatic stress memory may have the potential to lead to undesirable activation of neuro-inflammatory processes. These theories could have a significant impact on the

  11. Frequency of fragile X chromosome in normal females.

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    Abuelo, D; Castree, K; Pueschel, S; Padre-Mendoza, T; Zolnierz, K

    1985-08-01

    Because of the ambiguities in diagnosing carriers of the fragile X syndrome, we studied thirty-six normal females to determine whether the fragile site at Xq27 can be seen in noncarrier females and at what frequency. A fragile site at Xq27 was identified in one out of thirty-six females, occurring at a frequency of 0.5% in her peripheral lymphocytes. We conclude that the fragile Xq27 site occurs only rarely in noncarrier females and that each laboratory should determine its own baseline frequencies of fragile X in order to most accurately distinguish between normal and carrier women.

  12. Expression and identification of folate-sensitive fragile sites in British Suffolk sheep (Ovis aries)

    Indian Academy of Sciences (India)

    Ahmad Ali; Muhammad Abdullah; Masroor Ellahi Babar; Khalid Javed; Asif Nadeem

    2008-12-01

    An investigation to understand the dynamics and biological significance of fragile site expression, and identification of 5-fluorodeoxyuridine (FUdR) induced chromosomal gaps/breaks, were carried out in an experimental flock of 45 Suffolk sheep. The statistical comparison revealed, highly significant variation in the frequency of chromosomal fragile site expression between control and FUdR cultures. Mean (± S.D.) values for cells with gaps and breaks, or aberrant cell count (AC), and the number of aberrations (NoA) per animal were 2.02 ± 0.34, 2.42 ± 0.48, 13.26 ± 0.85 and 21.87 ± 1.88 ($P \\lt 0.01$) in control and FUdR cultures, respectively. The comparison of age revealed nonsignificant variation between control and FUdR cultures. The G-band analysis of fragile site data revealed gaps in 29 autosomal and two X-chromosomal bands in the control cultures, whereas FUdR treated cultures scored 78 unstable bands in autosomes of which 56 were significantly fragile. X-chromosomes expressed breaks and gaps in six G-negative bands and five of them (Xq13, Xq15, Xq17, Xq24 and Xq26) were significantly fragile. The distribution comparison of autosomal fragile sites between sex groups did not reveal any significant variation. Female X-chromosomes were significantly more fragile than the male X-chromosomes. The distribution comparison for age groups (lambs versus adults) revealed significantly higher number of fragile bands in adults. Comparison of published data on reciprocal translocations in sheep with the fragile-site data obtained in this study indicated that the break sites of both phenomena were correlated. Similarities were also found between fragile sites and breakpoints of evolutionary significance in family Bovidae.

  13. Occurrence of aneuploidy for the X chromosome in over 1,300 unrelated specimens screened for the fragile X chromosome

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-07-15

    An apparent association between the occurrence of the fragile X syndrome and Klinefelter and Down syndromes has been reported over the past few years. We reported 3 cells with extra X chromosomes [XXY (one cell), XXXY (2 cells)] in a fragile X male who exhibited 37 fragile X chromosomes in 200 cells studied. After making this observation, we decided to determine the number of X chromosomes in all fragile X chromosome analyses to see if there was any increased mitotic nondisjunction for the X chromosome. We conclude that there was no association between the fragile X syndrome and X chromosome mitotic nondisjunction/aneuploidy in this group of individuals. 9 refs., 1 tab.

  14. Increased chromosome fragility as a consequence of blood folate levels, smoking status, and coffee consumption

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.T.L.; Reidy, J.A.; Annest, J.L.; Welty, T.K.; Zhou, H. (Centers for Disease Control, Atlanta, GA (USA))

    1989-01-01

    Chromosome fragility in 96 h, low-folate cultures was found to be associated with smoking status, coffee consumption, and blood folate level. The higher proportion of cells with chromosome aberrations in cigarette smokers was attributable to lower red cell folate levels in smokers compared with nonsmokers. There was a positive linear relationship between the average cups of coffee consumed per day and the proportion of cells with aberrations. This association was independent of the effects of smoking and red cell folate level. These data suggest that smoking history, coffee consumption, and red cell folate level are important considerations for the design and interpretation of fragile site studies in cancer cytogenetics.

  15. Transcription-replication conflicts at chromosomal fragile sites—consequences in M phase and beyond

    DEFF Research Database (Denmark)

    Østergaard, Vibe Hallundbæk; Lisby, Michael

    2017-01-01

    transcription and replication patterns. At the same time, these chromosomal fragile sites engage in aberrant DNA structures in mitosis. Here, we discuss the mechanistic details of transcription–replication conflicts including putative scenarios for R-loop-induced replication inhibition to understand how...... transcription–replication conflicts transition from S phase into various aberrant DNA structures in mitosis....

  16. Detection of skewed X-chromosome inactivation in Fragile X syndrome and X chromosome aneuploidy using quantitative melt analysis.

    Science.gov (United States)

    Godler, David E; Inaba, Yoshimi; Schwartz, Charles E; Bui, Quang M; Shi, Elva Z; Li, Xin; Herlihy, Amy S; Skinner, Cindy; Hagerman, Randi J; Francis, David; Amor, David J; Metcalfe, Sylvia A; Hopper, John L; Slater, Howard R

    2015-07-01

    Methylation of the fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary positioned fragile X related epigenetic element 2 (FREE2), reveals skewed X-chromosome inactivation (XCI) in fragile X syndrome full mutation (FM: CGG > 200) females. XCI skewing has been also linked to abnormal X-linked gene expression with the broader clinical impact for sex chromosome aneuploidies (SCAs). In this study, 10 FREE2 CpG sites were targeted using methylation specific quantitative melt analysis (MS-QMA), including 3 sites that could not be analysed with previously used EpiTYPER system. The method was applied for detection of skewed XCI in FM females and in different types of SCA. We tested venous blood and saliva DNA collected from 107 controls (CGG chromosome test; (ii) locus-specific XCI skewing towards the hypomethylated state in FM females; and (iii) skewed XCI towards the hypermethylated state in SCA with 3 or more X chromosomes, and in 5% of the 47,XXY individuals. MS-QMA output also showed significant correlation with the EpiTYPER reference method in FM males and females (P < 0.0001) and SCAs (P < 0.05). In conclusion, we demonstrate use of MS-QMA to quantify skewed XCI in two applications with diagnostic utility.

  17. Common fragile site profiling in epithelial and erythroid cells reveals that most recurrent cancer deletions lie in fragile sites hosting large genes.

    Science.gov (United States)

    Le Tallec, Benoît; Millot, Gaël Armel; Blin, Marion Esther; Brison, Olivier; Dutrillaux, Bernard; Debatisse, Michelle

    2013-08-15

    Cancer genomes exhibit numerous deletions, some of which inactivate tumor suppressor genes and/or correspond to unstable genomic regions, notably common fragile sites (CFSs). However, 70%-80% of recurrent deletions cataloged in tumors remain unexplained. Recent findings that CFS setting is cell-type dependent prompted us to reevaluate the contribution of CFS to cancer deletions. By combining extensive CFS molecular mapping and a comprehensive analysis of CFS features, we show that the pool of CFSs for all human cell types consists of chromosome regions with genes over 300 kb long, and different subsets of these loci are committed to fragility in different cell types. Interestingly, we find that transcription of large genes does not dictate CFS fragility. We further demonstrate that, like CFSs, cancer deletions are significantly enriched in genes over 300 kb long. We now provide evidence that over 50% of recurrent cancer deletions originate from CFSs associated with large genes.

  18. Correlated fragile site expression allows the identification of candidate fragile genes involved in immunity and associated with carcinogenesis

    Directory of Open Access Journals (Sweden)

    Puliti Alda

    2006-09-01

    Full Text Available Abstract Background Common fragile sites (cfs are specific regions in the human genome that are particularly prone to genomic instability under conditions of replicative stress. Several investigations support the view that common fragile sites play a role in carcinogenesis. We discuss a genome-wide approach based on graph theory and Gene Ontology vocabulary for the functional characterization of common fragile sites and for the identification of genes that contribute to tumour cell biology. Results Common fragile sites were assembled in a network based on a simple measure of correlation among common fragile site patterns of expression. By applying robust measurements to capture in quantitative terms the non triviality of the network, we identified several topological features clearly indicating departure from the Erdos-Renyi random graph model. The most important outcome was the presence of an unexpected large connected component far below the percolation threshold. Most of the best characterized common fragile sites belonged to this connected component. By filtering this connected component with Gene Ontology, statistically significant shared functional features were detected. Common fragile sites were found to be enriched for genes associated to the immune response and to mechanisms involved in tumour progression such as extracellular space remodeling and angiogenesis. Moreover we showed how the internal organization of the graph in communities and even in very simple subgraphs can be a starting point for the identification of new factors of instability at common fragile sites. Conclusion We developed a computational method addressing the fundamental issue of studying the functional content of common fragile sites. Our analysis integrated two different approaches. First, data on common fragile site expression were analyzed in a complex networks framework. Second, outcomes of the network statistical description served as sources for the

  19. The fragile Y hypothesis: Y chromosome aneuploidy as a selective pressure in sex chromosome and meiotic mechanism evolution.

    Science.gov (United States)

    Blackmon, Heath; Demuth, Jeffery P

    2015-09-01

    Loss of the Y-chromosome is a common feature of species with chromosomal sex determination. However, our understanding of why some lineages frequently lose Y-chromosomes while others do not is limited. The fragile Y hypothesis proposes that in species with chiasmatic meiosis the rate of Y-chromosome aneuploidy and the size of the recombining region have a negative correlation. The fragile Y hypothesis provides a number of novel insights not possible under traditional models. Specifically, increased rates of Y aneuploidy may impose positive selection for (i) gene movement off the Y; (ii) translocations and fusions which expand the recombining region; and (iii) alternative meiotic segregation mechanisms (achiasmatic or asynaptic). These insights as well as existing evidence for the frequency of Y-chromosome aneuploidy raise doubt about the prospects for long-term retention of the human Y-chromosome despite recent evidence for stable gene content in older non-recombining regions.

  20. Fragile X syndrome and an isodicentric X chromosome in a woman with multiple anomalies, developmental delay, and normal pubertal development.

    Science.gov (United States)

    Freedenberg, D L; Gane, L W; Richards, C S; Lampe, M; Hills, J; O'Connor, R; Manchester, D; Taylor, A; Tassone, F; Hulseberg, D; Hagerman, R J; Patil, S R

    1999-07-30

    We report on an individual with developmental delays, short stature, skeletal abnormalities, normal pubertal development, expansion of the fragile X triplet repeat, as well as an isodicentric X chromosome. S is a 19-year-old woman who presented for evaluation of developmental delay. Pregnancy was complicated by a threatened miscarriage. She was a healthy child with intellectual impairment noted in infancy. Although she had global delays, speech was noted to be disproportionately delayed with few words until age 3.5 years. Facial appearance was consistent with fragile X syndrome. Age of onset of menses was 11 years with normal breast development. A maternal male second cousin had been identified with fragile X syndrome based on DNA studies. The mother of this child (S's maternal first cousin) and the grandfather (S's maternal uncle) were both intellectually normal but were identified as carrying triplet expansions in the premutation range. S's mother had some school difficulties but was not identified as having global delays. Molecular analysis of S's fragile X alleles noted an expansion of more than 400 CGG repeats in one allele. Routine cytogenetic studies of peripheral blood noted the presence of an isodicentric X in 81of 86 cells scored. Five of 86 cells were noted to be 45,X. Cytogenetic fra(X) studies from peripheral blood showed that the structurally normal chromosome had the fragile site in approximately 16% of the cells. Analysis of maternal fragile X alleles identified an allele with an expansion to approximately 110 repeats. FMRP studies detected the expression of the protein in 24% of cells studied. To our knowledge, this is the first patient reported with an isodicentric X and fragile X syndrome. Whereas her clinical phenotype is suggestive of fragile X syndrome, her skeletal abnormalities may represent the presence of the isodicentric X. Treatment of S with 20 mg/day of Prozac improved her behavior. In the climate of cost con trol, this individual

  1. Break-seq reveals hydroxyurea-induced chromosome fragility as a result of unscheduled conflict between DNA replication and transcription.

    Science.gov (United States)

    Hoffman, Elizabeth A; McCulley, Andrew; Haarer, Brian; Arnak, Remigiusz; Feng, Wenyi

    2015-03-01

    We have previously demonstrated that in Saccharomyces cerevisiae replication, checkpoint inactivation via a mec1 mutation leads to chromosome breakage at replication forks initiated from virtually all origins after transient exposure to hydroxyurea (HU), an inhibitor of ribonucleotide reductase. Here we sought to determine whether all replication forks containing single-stranded DNA gaps have equal probability of producing double-strand breaks (DSBs) when cells attempt to recover from HU exposure. We devised a new methodology, Break-seq, that combines our previously described DSB labeling with next generation sequencing to map chromosome breaks with improved sensitivity and resolution. We show that DSBs preferentially occur at genes transcriptionally induced by HU. Notably, different subsets of the HU-induced genes produced DSBs in MEC1 and mec1 cells as replication forks traversed a greater distance in MEC1 cells than in mec1 cells during recovery from HU. Specifically, while MEC1 cells exhibited chromosome breakage at stress-response transcription factors, mec1 cells predominantly suffered chromosome breakage at transporter genes, many of which are the substrates of those transcription factors. We propose that HU-induced chromosome fragility arises at higher frequency near HU-induced genes as a result of destabilized replication forks encountering transcription factor binding and/or the act of transcription. We further propose that replication inhibitors can induce unscheduled encounters between replication and transcription and give rise to distinct patterns of chromosome fragile sites.

  2. Estimating tempo and mode of Y chromosome turnover: explaining Y chromosome loss with the fragile Y hypothesis.

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    Blackmon, Heath; Demuth, Jeffery P

    2014-06-01

    Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain phylogenetic breadth we therefore assembled a database of 4724 beetle species' karyotypes and found substantial variation in sex chromosome systems. We used the data to estimate rates of Y chromosome gain and loss across a phylogeny of 1126 taxa estimated from seven genes. Contrary to our initial expectations, we find that highly degenerated Y chromosomes of many members of the suborder Polyphaga are rarely lost, and that cases of Y chromosome loss are strongly associated with chiasmatic segregation during male meiosis. We propose the "fragile Y" hypothesis, that recurrent selection to reduce recombination between the X and Y chromosome leads to the evolution of a small pseudoautosomal region (PAR), which, in taxa that require XY chiasmata for proper segregation during meiosis, increases the probability of aneuploid gamete production, with Y chromosome loss. This hypothesis predicts that taxa that evolve achiasmatic segregation during male meiosis will rarely lose the Y chromosome. We discuss data from mammals, which are consistent with our prediction.

  3. Fluorescent in-situ hybridization of cattle and sheep chromosomes with cloned human fragile-X DNA

    DEFF Research Database (Denmark)

    Ali, Ahmd; Thomsen, Preben Dybdahl; Babar, M.E.

    2009-01-01

    An extensive study on spontaneous and 5-Fluorodeoxyuridine induced fragile sites identified Xq31 in cattle (Bos taurus) and (Xq24, Xq26) in sheep (Ovis aries) in addition to several autosomal fragile sites (under publication). A ZOO-FISH study using three cloned human fragile-X probes with CCG/CG...

  4. Plant 45S rDNA clusters are fragile sites and their instability is associated with epigenetic alterations.

    Directory of Open Access Journals (Sweden)

    Min Huang

    Full Text Available Our previous study demonstrated that 45S ribosomal DNA (45S rDNA clusters were chromosome fragile sites expressed spontaneously in Lolium. In this study, fragile phenotypes of 45S rDNA were observed under aphidicolin (APH incubation in several plant species. Further actinomycin D (ActD treatment showed that transcriptional stress might interfere with chromatin packaging, resulting in 45S rDNA fragile expression. These data identified 45S rDNA sites as replication-dependent as well as transcription-dependent fragile sites in plants. In the presence of ActD, a dramatic switch to an open chromatin conformation and accumulated incomplete 5' end of the external transcribed spacer (5'ETS transcripts were observed, accompanied by decreased DNA methylation, decreased levels of histone H3, and increased histone acetylation and levels of H3K4me2, suggesting that these epigenetic alterations are associated with failure of 45S rDNA condensation. Furthermore, the finding that γ-H2AX was accumulated at 45S rDNA sites following ActD treatment suggested that the DNA damage signaling pathway was associated with the appearance of 45S rDNA fragile phenotypes. Our data provide a link between 45S rDNA transcription and chromatin-packaging defects and open the door for further identifying the molecular mechanism involved.

  5. Comparative analysis of chicken chromosome 28 provides new clues to the evolutionary fragility of gene-rich vertebrate regions.

    Science.gov (United States)

    Gordon, Laurie; Yang, Shan; Tran-Gyamfi, Mary; Baggott, Dan; Christensen, Mari; Hamilton, Aaron; Crooijmans, Richard; Groenen, Martien; Lucas, Susan; Ovcharenko, Ivan; Stubbs, Lisa

    2007-11-01

    The chicken genome draft sequence has provided a valuable resource for studies of an important agricultural and experimental model species and an important data set for comparative analysis. However, some of the most gene-rich segments are missing from chicken genome draft assemblies, limiting the analysis of a substantial number of genes and preventing a closer look at regions that are especially prone to syntenic rearrangements. To facilitate the functional and evolutionary analysis of one especially gene-rich, rearrangement-prone genomic region, we analyzed sequence from BAC clones spanning chicken microchromosome GGA28; as a complement we also analyzed a gene-sparse, stable region from GGA11. In these two regions we documented the conservation and lineage-specific gain and loss of protein-coding genes and precisely mapped the locations of 31 major human-chicken syntenic breakpoints. Altogether, we identified 72 lineage-specific genes, many of which are found at or near syntenic breaks, implicating evolutionary breakpoint regions as major sites of genetic innovation and change. Twenty-two of the 31 breakpoint regions have been reused repeatedly as rearrangement breakpoints in vertebrate evolution. Compared with stable GC-matched regions, GGA28 is highly enriched in CpG islands, as are break-prone intervals identified elsewhere in the chicken genome; evolutionary breakpoints are further enriched in GC content and CpG islands, highlighting a potential role for these features in genome instability. These data support the hypothesis that chromosome rearrangements have not occurred randomly over the course of vertebrate evolution but are focused preferentially within "fragile" regions with unusual DNA sequence characteristics.

  6. Molecular Cloning and Preliminary Analysis of a Fragile Site Associated Gene

    Institute of Scientific and Technical Information of China (English)

    YI-WEN CAO; CHUAN-LU JIANG; TAO JIANG

    2006-01-01

    Objective To analyze the molecular colning of a fragile site-associated gene. Methods Genomic Chinese hamster ovary (CHO) DNA library was constructed using high molecular weight CHO DNA partially digested with MboI restriction enzyme from cultured CHO cells. Screening of genomic DNA library followed the established procedures. Genomic CHO in the positive clones was sequenced. Appropriate primers were designed for the reverse transcriptase-polymerase chain reactions (RT-PCR). The RT-PCR products were cloned into a pCRⅡ TOPO vector and confirmed by DNA sequencing. Antibodies were prepared using synthetic peptides as antigens by immunizing the rabbits. Immunohistochemical analyses were performed to evaluate the expression of the novel gene in different tissues. Results To investigate the molecular mechanism underlying the initial events of mdrla amplification, we cloned 1q31 fragile site DNA. Strikingly, we found that this fragile site contained a novel gene which was designated as a fragile site-associated (FSA) gene. FSA encoded an unusually large mRNA of ~16 kb. Full-length human FSA cDNA was cloned. FSA mRNA was expressed in many cultured cells and tissue types. Immunohistochemical analyses also revealed an expression pattern of the encoded proteins in postmitotic, well-differentiated epithelial compartments of many organs, including colon, mammary glands, ovary, prostate, and bladder. Conclusion FSA plays an important role in regulating mammalian epithelial cell growth and differentiation.

  7. Absence of Y chromosome in human placental site trophoblastic tumor.

    Science.gov (United States)

    Hui, Pei; Wang, Hanlin L; Chu, Peiguo; Yang, Bin; Huang, Jiaoti; Baergen, Rebecca N; Sklar, Jeffrey; Yang, Ximing J; Soslow, Robert A

    2007-10-01

    Placental site trophoblastic tumor is a neoplasm of extravillous intermediate trophoblast at the implantation site, preceded in the majority of cases by a female gestational event. Our pilot investigation suggested that the development of this tumor might require a paternally derived X chromosome and the absence of a Y chromosome. Twenty cases of placental site trophoblastic tumor were included in this study. Genotyping at 15 polymorphic loci and one sex determination locus was performed by multiplex PCR followed by capillary electrophoresis. X chromosome polymorphisms were determined by PCR amplification of exon 1 of the human androgen receptor gene using primers flanking the polymorphic CAG repeats within this region. Genotyping at 15 polymorphic loci was informative and paternal alleles were present in all tumors, confirming the trophoblastic origin of the tumors. The presence of an X chromosome and the absence of a Y chromosome were observed in all tumors. Among 13 cases in which analysis of the X chromosome polymorphism was informative, all but one demonstrated at least two X alleles and seven cases showed one identifiable paternal X allele. These results confirm a unique pathogenetic mechanism in placental site trophoblastic tumor, involving an exclusion of the Y chromosome from the genome and, therefore, a tumor arising from the trophectoderm of a female conceptus. As epigenetic regulations of imprinting during X chromosome inactivation are of significant biological implications, placental site trophoblastic tumor may provide an important model for studying the sex chromosome biology and the proliferative advantage conferred by the paternal X chromosome.

  8. Significance of fragile site examination in children with mental retardation%智力低下儿脆性位点检查的意义

    Institute of Scientific and Technical Information of China (English)

    慕明涛; 霍满鹏; 张静; 刘俊俊; 蒲力群

    2013-01-01

    Objective: To explore the significance of chromosomal technique for diagnosing the causes of mental retardation. Methods: Eighty - six children with mental retardation were selected, then routine preparation of chromosomal samples of lymphocytes in peripheral blood, G band, karyotyping under microscope, and research on chromosomal fragile site expression were performed; 30 normal children were selected as control group. Results: Among 86 children with mental retardation, 24 children were found with abnormal karyotypes, the detection rate was 27. 91%. The incidence rates of chromosomal fragile site in experimental group and control group were 25. 02% and 5. 27% , respectively, there was statistically significant difference between the two groups (P <0. 01) . Conclusion: Chromosomal abnormality is one of important causes of mental retardation, there is a certain correlation between mental retardation and chromosomal aberration, expression rate of fragile site.%目的:探讨应用染色体技术诊断智力低下病因的意义.方法:对86例智力低下儿应用常规外周血淋巴细胞染色体标本制备、G显带、镜下核型分析和染色体脆性位点表达研究,另选正常儿童30例为对照组.结果:86例受检者中检出异常核型24例,检出率为27.91%.实验组染色体脆性位点的发生率为25.02%,对照组为5.27%,两组相比差异有统计学意义(P<0.01).结论:染色体异常是导致智力低下发生的重要原因之一,智力低下与染色体畸变和脆性部位表达率有一定的相关性.

  9. Fragility in the 14q21q translocation region

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    Stacy R. Denison

    2002-01-01

    Full Text Available Aphidicolin (APC-induced chromosomal breakage was analyzed for women representing three generations of a single family and carrying a Robertsonian translocation rob(14q21q. Fluorescence in situ hybridization (FISH analysis confirmed the dicentric constitution of the derived chromosome and indicated the absence of beta-satellite signal at the translocation region. Per-individual analysis of metaphases from APC-treated peripheral blood lymphocyte cultures identified significantly nonrandom chromosomal breakage at the translocation region in all three individuals examined. The APC-inducible fragility at the 14q21q translocation region suggests that this rearrangement was the result of chromosomal mutation at fragile site(s in the progenitor chromosomes, or that this fragility was the result of the fusion of nonfragile progenitor chromosomes.

  10. Increased expression of aphidicolin-induced common fragile sites in Tourette syndrome: The key to understand the genetics of comorbid phenotypes?

    Energy Technology Data Exchange (ETDEWEB)

    Gericke, G.S.; Simonic, I.; Cloete, E.; Becker, P.J. [Univ. of Pretoria (South Africa)

    1996-02-16

    In a comparison of 80 common aphidicolin-induced fragile sites (FS) between 26 DSM-IV Tourette syndrome (TS) and 24 control individuals, the mean of the summed break frequencies following mild aphidicolin pretreatment was significantly higher in TS individuals than in controls (P < 0.001). Other breakpoints encountered during this study, i.e., random breaks, breaks corresponding to rare FS, and breakpoints recorded by others but not listed as common FS according to the Chromosome Coordinating Meeting were listed as category II breakpoints. By using the most significantly different mean FS breakage figures between TS and control individuals, further stepwise discriminant analysis allowed identification of TS individuals from only a few sites in both the common FS and category II breakpoint groups. Future research needs to focus on confirmation of altered common fragile site expression in association with behavioral variation, whether expression of certain discriminatory sites concurs with specific comorbid disorder expression; the nature of the molecular alterations at these FS and the implications of a genomic instability phenotype for the mapping of a primary TS gene or genes. 45 refs., 1 fig., 2 tabs.

  11. DNA break site at fragile subtelomeres determines probability and mechanism of antigenic variation in African trypanosomes.

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    Lucy Glover

    2013-03-01

    Full Text Available Antigenic variation in African trypanosomes requires monoallelic transcription and switching of variant surface glycoprotein (VSG genes. The transcribed VSG, always flanked by '70 bp'-repeats and telomeric-repeats, is either replaced through DNA double-strand break (DSB repair or transcriptionally inactivated. However, little is known about the subtelomeric DSBs that naturally trigger antigenic variation in Trypanosoma brucei, the subsequent DNA damage responses, or how these responses determine the mechanism of VSG switching. We found that DSBs naturally accumulate close to both transcribed and non-transcribed telomeres. We then induced high-efficiency meganuclease-mediated DSBs and monitored DSB-responses and DSB-survivors. By inducing breaks at distinct sites within both transcribed and silent VSG transcription units and assessing local DNA resection, histone modification, G2/M-checkpoint activation, and both RAD51-dependent and independent repair, we reveal how breaks at different sites trigger distinct responses and, in 'active-site' survivors, different switching mechanisms. At the active site, we find that promoter-adjacent breaks typically failed to trigger switching, 70 bp-repeat-adjacent breaks almost always triggered switching through 70 bp-repeat recombination (∼60% RAD51-dependent, and telomere-repeat-adjacent breaks triggered switching through loss of the VSG expression site (25% of survivors. Expression site loss was associated with G2/M-checkpoint bypass, while 70 bp-repeat-recombination was associated with DNA-resection, γH2A-focus assembly and a G2/M-checkpoint. Thus, the probability and mechanism of antigenic switching are highly dependent upon the location of the break. We conclude that 70 bp-repeat-adjacent and telomere-repeat-adjacent breaks trigger distinct checkpoint responses and VSG switching pathways. Our results show how subtelomere fragility can generate the triggers for the major antigenic variation mechanisms in

  12. DNA break site at fragile subtelomeres determines probability and mechanism of antigenic variation in African trypanosomes.

    Science.gov (United States)

    Glover, Lucy; Alsford, Sam; Horn, David

    2013-03-01

    Antigenic variation in African trypanosomes requires monoallelic transcription and switching of variant surface glycoprotein (VSG) genes. The transcribed VSG, always flanked by '70 bp'-repeats and telomeric-repeats, is either replaced through DNA double-strand break (DSB) repair or transcriptionally inactivated. However, little is known about the subtelomeric DSBs that naturally trigger antigenic variation in Trypanosoma brucei, the subsequent DNA damage responses, or how these responses determine the mechanism of VSG switching. We found that DSBs naturally accumulate close to both transcribed and non-transcribed telomeres. We then induced high-efficiency meganuclease-mediated DSBs and monitored DSB-responses and DSB-survivors. By inducing breaks at distinct sites within both transcribed and silent VSG transcription units and assessing local DNA resection, histone modification, G2/M-checkpoint activation, and both RAD51-dependent and independent repair, we reveal how breaks at different sites trigger distinct responses and, in 'active-site' survivors, different switching mechanisms. At the active site, we find that promoter-adjacent breaks typically failed to trigger switching, 70 bp-repeat-adjacent breaks almost always triggered switching through 70 bp-repeat recombination (∼60% RAD51-dependent), and telomere-repeat-adjacent breaks triggered switching through loss of the VSG expression site (25% of survivors). Expression site loss was associated with G2/M-checkpoint bypass, while 70 bp-repeat-recombination was associated with DNA-resection, γH2A-focus assembly and a G2/M-checkpoint. Thus, the probability and mechanism of antigenic switching are highly dependent upon the location of the break. We conclude that 70 bp-repeat-adjacent and telomere-repeat-adjacent breaks trigger distinct checkpoint responses and VSG switching pathways. Our results show how subtelomere fragility can generate the triggers for the major antigenic variation mechanisms in the African

  13. Genomic rearrangements at the FRA2H common fragile site frequently involve non-homologous recombination events across LTR and L1(LINE) repeats.

    Science.gov (United States)

    Brueckner, Lena M; Sagulenko, Evgeny; Hess, Elisa M; Zheglo, Diana; Blumrich, Anne; Schwab, Manfred; Savelyeva, Larissa

    2012-08-01

    Common fragile sites (cFSs) are non-random chromosomal regions that are prone to breakage under conditions of replication stress. DNA damage and chromosomal alterations at cFSs appear to be critical events in the development of various human diseases, especially carcinogenesis. Despite the growing interest in understanding the nature of cFS instability, only a few cFSs have been molecularly characterised. In this study, we fine-mapped the location of FRA2H using six-colour fluorescence in situ hybridisation and showed that it is one of the most active cFSs in the human genome. FRA2H encompasses approximately 530 kb of a gene-poor region containing a novel large intergenic non-coding RNA gene (AC097500.2). Using custom-designed array comparative genomic hybridisation, we detected gross and submicroscopic chromosomal rearrangements involving FRA2H in a panel of 54 neuroblastoma, colon and breast cancer cell lines. The genomic alterations frequently involved different classes of long terminal repeats and long interspersed nuclear elements. An analysis of breakpoint junction sequence motifs predominantly revealed signatures of microhomology-mediated non-homologous recombination events. Our data provide insight into the molecular structure of cFSs and sequence motifs affected by their activation in cancer. Identifying cFS sequences will accelerate the search for DNA biomarkers and targets for individualised therapies.

  14. Comprehensive prediction of chromosome dimer resolution sites in bacterial genomes

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    Arakawa Kazuharu

    2011-01-01

    Full Text Available Abstract Background During the replication process of bacteria with circular chromosomes, an odd number of homologous recombination events results in concatenated dimer chromosomes that cannot be partitioned into daughter cells. However, many bacteria harbor a conserved dimer resolution machinery consisting of one or two tyrosine recombinases, XerC and XerD, and their 28-bp target site, dif. Results To study the evolution of the dif/XerCD system and its relationship with replication termination, we report the comprehensive prediction of dif sequences in silico using a phylogenetic prediction approach based on iterated hidden Markov modeling. Using this method, dif sites were identified in 641 organisms among 16 phyla, with a 97.64% identification rate for single-chromosome strains. The dif sequence positions were shown to be strongly correlated with the GC skew shift-point that is induced by replicational mutation/selection pressures, but the difference in the positions of the predicted dif sites and the GC skew shift-points did not correlate with the degree of replicational mutation/selection pressures. Conclusions The sequence of dif sites is widely conserved among many bacterial phyla, and they can be computationally identified using our method. The lack of correlation between dif position and the degree of GC skew suggests that replication termination does not occur strictly at dif sites.

  15. White matter microstructural abnormalities in girls with chromosome 22q11.2 deletion syndrome, Fragile X or Turner syndrome as evidenced by diffusion tensor imaging

    Science.gov (United States)

    Villalon, Julio; Jahanshad, Neda; Beaton, Elliott; Toga, Arthur W.; Thompson, Paul M.; Simon, Tony J.

    2014-01-01

    Children with chromosome 22q11.2 Deletion Syndrome (22q11.2DS), Fragile X Syndrome (FXS), or Turner Syndrome (TS) are considered to belong to distinct genetic groups, as each disorder is caused by separate genetic alterations. Even so, they have similar cognitive and behavioral dysfunctions, particularly in visuospatial and numerical abilities. To assess evidence for common underlying neural microstructural alterations, we set out to determine whether these groups have partially overlapping white matter abnormalities, relative to typically developing controls. We scanned 101 female children between 7 and 14 years old: 25 with 22q11.2DS, 18 with FXS, 17 with TS, and 41 aged-matched controls using diffusion tensor imaging (DTI). Anisotropy and diffusivity measures were calculated and all brain scans were nonlinearly aligned to population and site-specific templates. We performed voxel-based statistical comparisons of the DTI-derived metrics between each disease group and the controls, while adjusting for age. Girls with 22q11.2DS showed lower fractional anisotropy (FA) than controls in the association fibers of the superior and inferior longitudinal fasciculi, the splenium of the corpus callosum, and the corticospinal tract. FA was abnormally lower in girls with FXS in the posterior limbs of the internal capsule, posterior thalami, and precentral gyrus. Girls with TS had lower FA in the inferior longitudinal fasciculus, right internal capsule and left cerebellar peduncle. Partially overlapping neurodevelopmental anomalies were detected in all three neurogenetic disorders. Altered white matter integrity in the superior and inferior longitudinal fasciculi and thalamic to frontal tracts may contribute to the behavioral characteristics of all of these disorders. PMID:23602925

  16. Autism genetic database (AGD: a comprehensive database including autism susceptibility gene-CNVs integrated with known noncoding RNAs and fragile sites

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    Talebizadeh Zohreh

    2009-09-01

    Full Text Available Abstract Background Autism is a highly heritable complex neurodevelopmental disorder, therefore identifying its genetic basis has been challenging. To date, numerous susceptibility genes and chromosomal abnormalities have been reported in association with autism, but most discoveries either fail to be replicated or account for a small effect. Thus, in most cases the underlying causative genetic mechanisms are not fully understood. In the present work, the Autism Genetic Database (AGD was developed as a literature-driven, web-based, and easy to access database designed with the aim of creating a comprehensive repository for all the currently reported genes and genomic copy number variations (CNVs associated with autism in order to further facilitate the assessment of these autism susceptibility genetic factors. Description AGD is a relational database that organizes data resulting from exhaustive literature searches for reported susceptibility genes and CNVs associated with autism. Furthermore, genomic information about human fragile sites and noncoding RNAs was also downloaded and parsed from miRBase, snoRNA-LBME-db, piRNABank, and the MIT/ICBP siRNA database. A web client genome browser enables viewing of the features while a web client query tool provides access to more specific information for the features. When applicable, links to external databases including GenBank, PubMed, miRBase, snoRNA-LBME-db, piRNABank, and the MIT siRNA database are provided. Conclusion AGD comprises a comprehensive list of susceptibility genes and copy number variations reported to-date in association with autism, as well as all known human noncoding RNA genes and fragile sites. Such a unique and inclusive autism genetic database will facilitate the evaluation of autism susceptibility factors in relation to known human noncoding RNAs and fragile sites, impacting on human diseases. As a result, this new autism database offers a valuable tool for the research

  17. Prevalence of Sarcopenia and Its Relationship with Sites of Fragility Fractures in Elderly Chinese Men and Women.

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    Wei Hong

    Full Text Available Sarcopenia might be associated with bone fragility in elderly individuals. This study aimed to investigate the prevalence of sarcopenia and its association with fragility fracture sites in elderly Chinese patients.Patients (322 men and 435 women aged 65-94 years and with a history of fragility fractures in the ankle, wrist, vertebrae or hip, and healthy men (n = 1263 and women (n = 1057 aged 65-92 years without a history of fractures were enrolled. Whole-body dual energy X-ray absorptiometry was used to analyze skeletal muscle mass index (SMI, fat mass and bone mineral density. Sarcopenia was defined as SMI less than two standard deviations below the mean of a young reference group.Sarcopenia occurrence varied with fracture location. Sarcopenia was more common in females with vertebral and hip fractures and in men with hip and ankle fractures than in the non-fracture group. Sarcopenia was significantly more prevalent in men with wrist, hip and ankle fractures than in women. SMI was correlated with BMD in different fracture groups. Logistic regression analyses revealed that lower SMI was associated with an increased risk of hip fracture both in men and women and ankle fracture in men.Sarcopenia may be an independent risk factor for hip and ankle fractures in men, and for hip fractures in women.

  18. Scarless and site-directed mutagenesis in Salmonella enteritidis chromosome

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    Berghman Luc R

    2007-09-01

    Full Text Available Abstract Background A variety of techniques have been described which introduce scarless, site-specific chromosomal mutations. These techniques can be applied to make point mutations or gene deletions as well as insert heterologous DNA into bacterial vectors for vaccine development. Most methods use a multi-step approach that requires cloning and/or designing repeat sequences to facilitate homologous recombination. We have modified previously published techniques to develop a simple, efficient PCR-based method for scarless insertion of DNA into Salmonella enteritidis chromosome. Results The final product of this mutation strategy is the insertion of DNA encoding a foreign epitope into the S. enteritidis genome without the addition of any unwanted sequence. This experiment was performed by a two-step mutation process via PCR fragments, Red recombinase and counter-selection with the I-SceI enzyme site. First, the I-SceI site and kanamycin resistance gene were introduced into the genome of cells expressing Red recombinase enzymes. Next, this sequence was replaced by a chosen insertion sequence. DNA fragments used for recombination were linear PCR products which consisted of the foreign insertion sequence flanked by homologous sequences of the target gene. Described herein is the insertion of a section of the M2e epitope (LM2 of Influenza A virus, a domain of CD154 (CD154s or a combination of both into the outer membrane protein LamB of S. enteritidis. Conclusion We have successfully used this method to produce multiple mutants with no antibiotic gene on the genome or extra sequence except those nucleotides required for expression of epitope regions. This method is advantageous over other protocols in that it does not require cloning or creating extra duplicate regions to facilitate homologous recombination, contains a universal construct in which an epitope of choice can be placed to check for cell surface expression, and shows high efficiency when

  19. Four chromosomal breakpoints and four new probes mark out a 10-cM region encompassing the fragile-X locus (FRAXA).

    Science.gov (United States)

    Rousseau, F; Vincent, A; Rivella, S; Heitz, D; Triboli, C; Maestrini, E; Warren, S T; Suthers, G K; Goodfellow, P; Mandel, J L

    1991-01-01

    We report the validation and use of a cell hybrid panel which allowed us a rapid physical localization of new DNA probes in the vicinity of the fragile-X locus (FRAXA). Seven regions are defined by this panel, two of which lie between DXS369 and DXS296, until now the closest genetic markers that flank FRAXA. Of those two interesting regions, one is just distal to DXS369 and defined by probe 2-71 (DXS476), which is not polymorphic. The next one contains probes St677 (DXS463) and 2-34 (DXS477), which are within 130 kb and both detect TaqI RFLPs. The combined informativeness of these two probes is 30%. We cloned from an irradiation-reduced hybrid line another new polymorphic probe, Do33 (DXS465; 42% heterozygosity). This probe maps to the DXS296 region, proximal to a chromosomal breakpoint that corresponds to the Hunter syndrome locus (IDS). The physical order is thus Cen-DXS369-DXS476-(DXS463,DXS477)-(DXS296, DXS465)-IDS-DXS304-tel. We performed a linkage analysis for five of these markers in both the Centre d'Etude du Polymorphisme Humain families and in a large set of fragile-X families. This establishes that DXS296 is distal to FRAXA. The relative position of DXS463 and DXS477 with respect to FRAXA remains uncertain, but our results place them genetically halfway between DXS369 and DXS304. Thus the DXS463-DXS477 cluster defines presently either the closest proximal or the closest distal polymorphic marker with respect to FRAXA. The three new polymorphic probes described here have a combined heterozygosity of 60% and represent a major improvement for genetic analysis of fragile-X families, in particular for diagnostic applications.

  20. Generalized Fragility Relationships with Local Site Conditions for Probabilistic Performance-based Seismic Risk Assessment of Bridge Inventories

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    Sivathayalan S.

    2012-01-01

    Full Text Available The current practice of detailed seismic risk assessment cannot be easily applied to all the bridges in a large transportation networks due to limited resources. This paper presents a new approach for seismic risk assessment of large bridge inventories in a city or national bridge network based on the framework of probabilistic performance based seismic risk assessment. To account for the influences of local site effects, a procedure to generate site-specific hazard curves that includes seismic hazard microzonation information has been developed for seismic risk assessment of bridge inventories. Simulated ground motions compatible with the site specific seismic hazard are used as input excitations in nonlinear time history analysis of representative bridges for calibration. A normalizing procedure to obtain generalized fragility relationships in terms of structural characteristic parameters of bridge span and size and longitudinal and transverse reinforcement ratios is presented. The seismic risk of bridges in a large inventory can then be easily evaluated using the normalized fragility relationships without the requirement of carrying out detailed nonlinear time history analysis.

  1. Analysis of the terminus region of the Caulobacter crescentus chromosome and identification of the dif site

    DEFF Research Database (Denmark)

    Jensen, Rasmus Bugge

    2006-01-01

    The terminus region of the Caulobacter crescentus chromosome and the dif chromosome dimer resolution site were characterized. The Caulobacter genome contains skewed sequences that abruptly switch strands at dif and may have roles in chromosome maintenance and segregation. Absence of dif or the Xer...

  2. CHARACTERIZATION AND CHROMOSOMAL ASSIGNMENT OF YEAST ARTIFICIAL CHROMOSOMES CONTAINING HUMAN 3P13-P21-SPECIFIC SEQUENCE-TAGGED SITES

    NARCIS (Netherlands)

    MICHAELIS, SC; BARDENHEUER, W; LUX, A; SCHRAMM, A; GOCKEL, A; SIEBERT, R; WILLERS, C; SCHMIDTKE, K; TODT, B; VANDERHOUT, AH; BUYS, CHCM; HEPPELLPARTON, AC; RABBITTS, PH; UNGAR, S; SMITH, D; LEPASLIER, D; COHEN, D; OPALKA, B; SCHUTTE, J

    1995-01-01

    Human chromosomal region 3p12-p23 is proposed to harbor at least three tumor suppressor genes involved in the development of lung cancer, renal cell carcinoma, and other neoplasias. In order to identify one of these genes we defined sequence tagged sites (STSs) specific for 3p13-p24.2 by analyzing a

  3. Chromosome

    Science.gov (United States)

    Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA ... is the building block of the human body. Chromosomes also contain proteins that help DNA exist in ...

  4. The yeast I-Sce I meganuclease induces site-directed chromosomal recombination in mammalian cells.

    Science.gov (United States)

    Choulika, A; Perrin, A; Dujon, B; Nicolas, J F

    1994-11-01

    Double-strand breaks in genomic DNA stimulate recombination. Until now it was not possible to induce in vivo site-directed double-strand breaks in a mammalian chromosomal target. In this article we describe the use of I-Sce I meganuclease, a very rare cutter yeast endonuclease, to induce site-directed double-strand breaks mediated recombination. The results demonstrate the potential of the I-Sce I system for chromosome manipulation in mammalian cells.

  5. Chromosome breakages associated with 45S ribosomal DNA sequences in spotted snakehead fish Channa punctatus.

    Science.gov (United States)

    Singh, Mamta; Barman, Anindya Sundar

    2013-01-01

    It is well known that transcriptionally inactive rRNA genes are correlated with DNA hyper-methylation and histone hypo-methylation and there is clear evidence in humans that DNA and histone modification which alter chromatin structure are related to chromosome fragility. Very little is known about the biological cause of 45S rDNA fragility. In this report we characterized the chromosome breakage or gap associated with 45S rDNA in a fish species Channa punctatus. The rDNA mapping in C. punctatus, showed many chromosome breakages or gap formations, and all occurred exclusively in the 45S rDNA sites in anterior kidney cells. We observed that the number of chromosomes plus chromosome fragments was often more than the expected 32 in most cells. Total 67 % metaphase spread showed the expected or normal 32 chromosomes, while 33 % metaphase spread showed 33 and/or 34 chromosomes and/or chromosome fragments. The chromosome lesions observed in this study are very similar cytologically to that of fragile sites observed in human chromosomes. Possible causes for the spontaneous expression of fragile sites and their potential biological significance are also discussed in present report.

  6. Fragile States

    DEFF Research Database (Denmark)

    Brock, Lothar; Holm, Hans-Henrik; Sørensen, Georg;

    What does state fragility means and how is it adressed. Case studies of where it went wrong and where it did not......What does state fragility means and how is it adressed. Case studies of where it went wrong and where it did not...

  7. Chromosomal manipulation by site-specific recombinases and fluorescent protein-based vectors.

    Directory of Open Access Journals (Sweden)

    Munehiro Uemura

    Full Text Available Feasibility of chromosomal manipulation in mammalian cells was first reported 15 years ago. Although this technique is useful for precise understanding of gene regulation in the chromosomal context, a limited number of laboratories have used it in actual practice because of associated technical difficulties. To overcome the practical hurdles, we developed a Cre-mediated chromosomal recombination system using fluorescent proteins and various site-specific recombinases. These techniques enabled quick construction of targeting vectors, easy identification of chromosome-rearranged cells, and rearrangement leaving minimum artificial elements at junctions. Applying this system to a human cell line, we successfully recapitulated two types of pathogenic chromosomal translocations in human diseases: MYC/IgH and BCR/ABL1. By inducing recombination between two loxP sites targeted into the same chromosome, we could mark cells harboring deletion or duplication of the inter-loxP segments with different colors of fluorescence. In addition, we demonstrated that the intrachromosomal recombination frequency is inversely proportional to the distance between two recombination sites, implicating a future application of this frequency as a proximity sensor. Our method of chromosomal manipulation can be employed for particular cell types in which gene targeting is possible (e.g. embryonic stem cells. Experimental use of this system would open up new horizons in genome biology, including the establishment of cellular and animal models of diseases caused by translocations and copy-number variations.

  8. The fragile X syndrome.

    Science.gov (United States)

    de Vries, B B; Halley, D J; Oostra, B A; Niermeijer, M F

    1998-01-01

    The fragile X syndrome is characterised by mental retardation, behavioural features, and physical features, such as a long face with large protruding ears and macro-orchidism. In 1991, after identification of the fragile X mental retardation (FMR1) gene, the cytogenetic marker (a fragile site at Xq27.3) became replaced by molecular diagnosis. The fragile X syndrome was one of the first examples of a "novel" class of disorders caused by a trinucleotide repeat expansion. In the normal population, the CGG repeat varies from six to 54 units. Affected subjects have expanded CGG repeats (>200) in the first exon of the FMR1 gene (the full mutation). Phenotypically normal carriers of the fragile X syndrome have a repeat in the 43 to 200 range (the premutation). The cloning of the FMR1 gene led to the characterisation of its protein product FMRP, encouraged further clinical studies, and opened up the possibility of more accurate family studies and fragile X screening programmes. Images PMID:9678703

  9. Centromere-independent accumulation of cohesin at ectopic heterochromatin sites induces chromosome stretching during anaphase.

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    Raquel A Oliveira

    2014-10-01

    Full Text Available Pericentric heterochromatin, while often considered as "junk" DNA, plays important functions in chromosome biology. It contributes to sister chromatid cohesion, a process mediated by the cohesin complex that ensures proper genome segregation during nuclear division. Long stretches of heterochromatin are almost exclusively placed at centromere-proximal regions but it remains unclear if there is functional (or mechanistic importance in linking the sites of sister chromatid cohesion to the chromosomal regions that mediate spindle attachment (the centromere. Using engineered chromosomes in Drosophila melanogaster, we demonstrate that cohesin enrichment is dictated by the presence of heterochromatin rather than centromere proximity. This preferential accumulation is caused by an enrichment of the cohesin-loading factor (Nipped-B/NIPBL/Scc2 at dense heterochromatic regions. As a result, chromosome translocations containing ectopic pericentric heterochromatin embedded in euchromatin display additional cohesin-dependent constrictions. These ectopic cohesion sites, placed away from the centromere, disjoin abnormally during anaphase and chromosomes exhibit a significant increase in length during anaphase (termed chromatin stretching. These results provide evidence that long stretches of heterochromatin distant from the centromere, as often found in many cancers, are sufficient to induce abnormal accumulation of cohesin at these sites and thereby compromise the fidelity of chromosome segregation.

  10. [Homologue pairing: initiation sites and effects on crossing over and chromosome disjunction in Drosophila melanogaster].

    Science.gov (United States)

    Chubykin, V L

    1996-01-01

    The role of homologue pairing and chromocentral association of chromosomes in recombination and segregation during cell division is discussed. Peculiarities of mitotic and meiotic chromosome pairing in Drosophila males and females are considered. On the basis of our own and published data, the presence and localization of sites of homologue pairing initiation in euchromatin are substantiated. The effects of transfer of initiation sites along a chromosome (exemplified by inversions) on chromosome pairing (asynapsis), crossing over (intrachromosomal, interchromosomal, and centromeric effects), and segregation are discussed. To record the effects of pairing sites on crossing over, a method of comparing crossing-over frequencies in an inverted region with those in a region of the same size and position with regard to the centromere on cytological maps was proposed. Chromosomes orient toward opposite division poles during paracentromeric heterochromatin pairing. This occurs after successful euchromatin pairing, during which the chromocentral circular structure is reorganized. If heterochromatin pairing is disrupted because of structural or locus mutations, nonexchange bivalents segregate randomly. In this case, chromosome coordination may occur due to proximal chiasmata or chromocentral associations between homologues.

  11. Prognostic Significance of Decreased Expression of Six Large Common Fragile Site Genes in Oropharyngeal Squamous Cell Carcinomas

    Directory of Open Access Journals (Sweden)

    Ge Gao

    2014-12-01

    Full Text Available Common fragile sites (CFSs are large regions with profound genomic instability that often span extremely large genes a number of which have been found to be important tumor suppressors. RNA sequencing previously revealed that there was a group of six large CFS genes which frequently had decreased expression in oropharyngeal squamous cell carcinomas (OPSCCs and real-time reverse transcriptase polymerase chain reaction experiments validated that these six large CFS genes (PARK2, DLG2, NBEA, CTNNA3, DMD, and FHIT had decreased expression in most of the tumor samples. In this study, we investigated whether the decreased expression of these genes has any clinical significance in OPSCCs. We analyzed the six CFS large genes in 45 OPSCC patients and found that 27 (60% of the OPSCC tumors had decreased expression of these six genes. When we correlated the expression of these six genes to each patient’s clinical records, for 11 patients who had tumor recurrence, 10 of them had decreased expression of almost all 6 genes. When we divided the patients into two groups, one group with decreased expression of the six genes and the other group with either slight changes or increased expression of the six genes, we found that there is significant difference in the incidence of tumor recurrence between these two groups by Kaplan-Meier plot analysis (P < .05. Our results demonstrated that those OPSCC tumors with decreased expression of this select group of six large CFS genes were much more likely to be associated with tumor recurrence and these genes are potential prognostic markers for predicting tumor recurrence in OPSCC.

  12. Site-specific genetic engineering of the Anopheles gambiae Y chromosome.

    Science.gov (United States)

    Bernardini, Federica; Galizi, Roberto; Menichelli, Miriam; Papathanos, Philippos-Aris; Dritsou, Vicky; Marois, Eric; Crisanti, Andrea; Windbichler, Nikolai

    2014-05-27

    Despite its function in sex determination and its role in driving genome evolution, the Y chromosome remains poorly understood in most species. Y chromosomes are gene-poor, repeat-rich and largely heterochromatic and therefore represent a difficult target for genetic engineering. The Y chromosome of the human malaria vector Anopheles gambiae appears to be involved in sex determination although very little is known about both its structure and function. Here, we characterize a transgenic strain of this mosquito species, obtained by transposon-mediated integration of a transgene construct onto the Y chromosome. Using meganuclease-induced homologous repair we introduce a site-specific recombination signal onto the Y chromosome and show that the resulting docking line can be used for secondary integration. To demonstrate its utility, we study the activity of a germ-line-specific promoter when located on the Y chromosome. We also show that Y-linked fluorescent transgenes allow automated sex separation of this important vector species, providing the means to generate large single-sex populations. Our findings will aid studies of sex chromosome function and enable the development of male-exclusive genetic traits for vector control.

  13. Distribution of 5S and 45S rDNA sites in plants with holokinetic chromosomes and the "chromosome field" hypothesis.

    Science.gov (United States)

    Sousa, A; Barros e Silva, A E; Cuadrado, A; Loarce, Y; Alves, M V; Guerra, M

    2011-08-01

    Secondary constrictions or 45S rDNA sites are commonly reported to be located mainly in the terminal regions of the chromosomes. This distribution has been assumed to be related to the existence of a "chromosome field" lying between the centromere and the telomere, an area in which certain cytogenetic events may predominantly occur. If this hypothesis is true this distribution should not be observed in holokinetic chromosomes, as they do not have a localized centromere. In order to evaluate this hypothesis, a comparative study was made of the distributions of 5S and 45S rDNA sites using fluorescence in situ hybridization in representatives of the genera Eleocharis, Diplacrum, Fimbristylis, Kyllinga and Rhynchospora, all of which belong to the family Cyperaceae. The numbers of sites per diploid chromosome complement varied from 2 to ∼10 for 5S rDNA, and from 2 to ∼45 for 45S rDNA. All of the 11 species analyzed had terminally located 45S rDNA sites on the chromosomes whereas the 5S rDNA sites also generally had terminal distributions, except for the Rhynchospora species, where their position was almost always interstitial. These results, together with other previously published data, suggest that the variation in the number and position of the rDNA sites in species with holokinetic chromosomes is non-random and similar to that reported for species with monocentric chromosomes. Therefore, the predominant terminal position of the 45S rDNA sites does not appear to be influenced by the centromere-telomere polarization as suggested by the "chromosome field" hypothesis. Additionally, the hybridization of 5S and 45S rDNA sites provides interesting markers to distinguish several chromosomes on the rather symmetrical karyotypes of Cyperaceae.

  14. Chromosome sites play dual roles to establish homologous synapsisduring meiosis in C. elegans

    Energy Technology Data Exchange (ETDEWEB)

    MacQueen, Amy J.; Phillips, Carolyn M.; Bhalla, Needhi; Weiser,Pinky; Villeneuve, Anne M.; Dernburg, Abby F.

    2005-06-05

    required for accurate segregation of homologous chromosomesduring meiosisin C. elegans. We find that these sites play two distinctroles that contribute to proper segregation. Chromosomes lacking PCsusually fail to synapse and also lack a synapsis-independentstabilization activity. The presence of a PC on justone copy of achromosome pair promotes synapsis but does not supportsynapsis-independent pairing stabilization, indicating that thesefunctions are separable. Once initiated, synapsis is highly processive,even between non homologous chromosomes of disparate lengths, elucidatinghow translocations suppress meiotic recombination in C. elegans. Thesefindings suggest a multistep pathway for chromosome synapsis in which PCsimpart selectivity and efficiency through a kinetic proofreadingmechanism. We speculate that concentration of these activities at oneregion per chromosome may have co-evolved with the loss of a pointcentromere to safeguard karyotype stability.

  15. Osmotic fragility test

    Science.gov (United States)

    Spherocytosis - osmotic fragility; Thalassemia - osmotic fragility ... done to detect conditions called hereditary spherocytosis and thalassemia . Hereditary spherocytosis makes red blood cells more fragile ...

  16. National Fragile X Foundation

    Science.gov (United States)

    ... Fragile X-associated Disorders Fragile X Syndrome (FXS) Autism Spectrum Disorder and Fragile X Syndrome FXTAS FXPOI Prevalence Carriers Genetics and Inheritance Testing for Fragile X Treatment & Intervention Consensus Documents on ...

  17. Extensive spreading of interstitial telomeric sites on the chromosomes of Characidium (Teleostei, Characiformes).

    Science.gov (United States)

    Scacchetti, Priscilla Cardim; Utsunomia, Ricardo; Pansonato-Alves, José Carlos; da Costa-Silva, Guilherme José; Oliveira, Claudio; Foresti, Fausto

    2015-06-01

    Characidium comprises several species of small freshwater fish that display conserved diploid chromosome numbers and karyotypic formulae. In this study, a comparative cytogenetic analysis using telomeric DNA probes was carried out in nine species of Characidium; a molecular phylogenetic analysis with mitochondrial DNA was also performed in order to investigate the direction of the evolutionary chromosome changes observed here. Our results showed the existence of species with several and variable interstitial telomeric sites (ITSs), with other species showing only terminal signals in their chromosomes. Molecular phylogenetic data suggested that these ITSs emerged once in the evolutionary history of Characidium and were later differentially spread in distinct species/populations of this clade. Additionally, the origin of an exclusive acrocentric pair found in C. pterostictum, C. serrano and C. timbuiense was also investigated, revealing that this pair possibly had a common origin to these species. These results evidence the occurrence of intense and continuous genomic changes among species of Characidium.

  18. A site required for termination of packaging of the phage lambda chromosome.

    Science.gov (United States)

    Cue, D; Feiss, M

    1993-10-15

    Lambda chromosomes are cut and packaged from concatemeric DNA by phage enzyme terminase. Terminase initiates DNA packaging by binding at a site called cosB and introducing staggered nicks at an adjacent site, cosN, to generate the left cohesive end of the DNA molecule to be packaged. After DNA packaging terminase recognizes and cuts the terminal cosN, an event that does not require a wild-type cosB. In this work a site, called cosQ, has been identified that is required for termination of DNA packaging. cosQ, defined by mutations in a sequence called R4, is located approximately 30 bp upstream from cosN. The order of sites is cosQ-cosN-cosB. Helper packaging of repressed, tandem prophage chromosomes demonstrated that a cosQ point mutation affects DNA packaging only when placed at the terminal cos site, whereas cosB mutations only affect packaging initiation. In vitro packaging studies confirmed that cosQ mutations do not affect packaging initiation. In vivo studies indicated that cosQ mutations do not affect cutting of initial cos sites but do cause a defect in packaging termination. cosQ mutants accumulated expanded phage heads, indicating that cosQ mutations affect a step that occurs after packaging of a substantial length of phage DNA. These results show that cosQ mutations define a site required for use of cos sites present at the ends of lambda chromosomes undergoing packaging. Available evidence suggests that other viruses, including phages T3 and T7 and the herpesviruses, may ultimately prove to use cosQ-like sites for packaging termination.

  19. A site required for termination of packaging of the phage lambda chromosome.

    OpenAIRE

    Cue, D; Feiss, M

    1993-01-01

    Lambda chromosomes are cut and packaged from concatemeric DNA by phage enzyme terminase. Terminase initiates DNA packaging by binding at a site called cosB and introducing staggered nicks at an adjacent site, cosN, to generate the left cohesive end of the DNA molecule to be packaged. After DNA packaging terminase recognizes and cuts the terminal cosN, an event that does not require a wild-type cosB. In this work a site, called cosQ, has been identified that is required for termination of DNA ...

  20. Chromosome segregation impacts on cell growth and division site selection in Corynebacterium glutamicum.

    Science.gov (United States)

    Donovan, Catriona; Schauss, Astrid; Krämer, Reinhard; Bramkamp, Marc

    2013-01-01

    Spatial and temporal regulation of bacterial cell division is imperative for the production of viable offspring. In many rod-shaped bacteria, regulatory systems such as the Min system and nucleoid occlusion ensure the high fidelity of midcell divisome positioning. However, regulation of division site selection in bacteria lacking recognizable Min and nucleoid occlusion remains less well understood. Here, we describe one such rod-shaped organism, Corynebacterium glutamicum, which does not always place the division septum precisely at midcell. Here we now show at single cell level that cell growth and division site selection are spatially and temporally regulated by chromosome segregation. Mutants defective in chromosome segregation have more variable cell growth and aberrant placement of the division site. In these mutants, division septa constrict over and often guillotine the nucleoid, leading to nonviable, DNA-free cells. Our results suggest that chromosome segregation or some nucleoid associated factor influences growth and division site selection in C. glutamicum. Understanding growth and regulation of C. glutamicum cells will also be of importance to develop strains for industrial production of biomolecules, such as amino acids.

  1. Chromosome segregation impacts on cell growth and division site selection in Corynebacterium glutamicum.

    Directory of Open Access Journals (Sweden)

    Catriona Donovan

    Full Text Available Spatial and temporal regulation of bacterial cell division is imperative for the production of viable offspring. In many rod-shaped bacteria, regulatory systems such as the Min system and nucleoid occlusion ensure the high fidelity of midcell divisome positioning. However, regulation of division site selection in bacteria lacking recognizable Min and nucleoid occlusion remains less well understood. Here, we describe one such rod-shaped organism, Corynebacterium glutamicum, which does not always place the division septum precisely at midcell. Here we now show at single cell level that cell growth and division site selection are spatially and temporally regulated by chromosome segregation. Mutants defective in chromosome segregation have more variable cell growth and aberrant placement of the division site. In these mutants, division septa constrict over and often guillotine the nucleoid, leading to nonviable, DNA-free cells. Our results suggest that chromosome segregation or some nucleoid associated factor influences growth and division site selection in C. glutamicum. Understanding growth and regulation of C. glutamicum cells will also be of importance to develop strains for industrial production of biomolecules, such as amino acids.

  2. Measurement of spatial proximity and accessibility of chromosomal loci in yeast using Cre/loxP site-specific recombination

    OpenAIRE

    Lui, Doris; Burgess, Sean M.

    2009-01-01

    Several methods have been developed to measure interactions between homologous chromosomes during meiosis in budding yeast. These include cytological analysis of fixed, spread nuclei using fluorescence in situ Hybridization (FISH) (1, 2), visualization of GFP-labeled chromosomal loci in living cells (3), and Chromosome-Conformation Capture (3C) (4). Here we describe a quantitative genetic assay that uses exogenous site-specific recombination to monitor the level of homolog associations betwee...

  3. Tagged Chromosomal Insertion Site System: A Method to Study Lamina-Associated Chromatin.

    Science.gov (United States)

    Harr, Jennifer C; Reddy, Karen L

    2016-01-01

    The three-dimensional (3D) organization of the genome is important for chromatin regulation. This organization is nonrandom and appears to be tightly correlated with or regulated by chromatin state and scaffolding proteins. To understand how specific DNA and chromatin elements contribute to the functional organization of the genome, we developed a new tool-the tagged chromosomal insertion site (TCIS) system-to identify and study minimal DNA sequences that drive nuclear compartmentalization and applied this system to specifically study the role of cis elements in targeting DNA to the nuclear lamina. The TCIS system allows Cre-recombinase-mediated site-directed integration of any DNA fragment into a locus tagged with lacO arrays, thus enabling both functional molecular studies and positional analysis of the altered locus. This system can be used to study the minimal DNA sequences that target the nuclear periphery (or other nuclear compartments), allowing researchers to understand how genome-wide results obtained, for example, by DNA adenine methyltransferase identification, chromosome conformation capture (HiC), or related methods, connect to the actual organization of DNA and chromosomes at the single-cell level. Finally, TCIS allows one to test roles for specific proteins in chromatin reorganization and to determine how changes in nuclear environment affect chromatin state and gene regulation at a single locus.

  4. A single copy integration vector that integrates at an engineered site on the Staphylococcus aureus chromosome

    Directory of Open Access Journals (Sweden)

    Lei Mei G

    2012-01-01

    Full Text Available Abstract Background Single-copy integration vectors based upon the site-specific recombination systems of bacteriophage are invaluable tools in the study of bacterial pathogenesis. The utility of such vectors is often limited, however, by the fact that integration often results in the inactivation of bacterial genes or has undesirable effects on gene transcription. The aim of this study is to develop an integration vector that does not have a detectable effect on gene transcription upon integration. Findings We have developed a single-copy integration system that enables the cloning vector to integrate at a specific engineered site, within an untranscribed intergenic region, in the chromosome of Staphylococcus aureus. This system is based on the lysogenic phage L54a site-specific recombination system in which the L54a phage (attP and chromosome (attB attachment sites, which share an 18-bp identical core sequence, were modified with identical mutations. The integration vector, pLL102, was constructed to contain the modified L54a attP site (attP2 that was altered at 5 nucleotide positions within the core sequence. In the recipient strain, the similarly modified attB site (attB2 was inserted in an intergenic region devoid of detectable transcription read-through. Integration of the vector, which is unable to replicate in S. aureus extrachromosomally, was achieved by providing the L54a integrase gene in a plasmid in the recipient. We showed that pLL102 integrated specifically at the engineered site rather than at the native L54a attB site and that integration did not have a significant effect on transcription of genes immediately upstream or downstream of the integration site. Conclusions In this work, we describe an E. coli-S. aureus shuttle vector that can be used to introduce any cloned gene into the S. aureus chromosome at a select site without affecting gene expression. The vector should be useful for genetic manipulation of S. aureus and for

  5. Preferential Breakpoints in the Recovery of Broken Dicentric Chromosomes in Drosophila melanogaster.

    Science.gov (United States)

    Hill, Hunter; Golic, Kent G

    2015-10-01

    We designed a system to determine whether dicentric chromosomes in Drosophila melanogaster break at random or at preferred sites. Sister chromatid exchange in a Ring-X chromosome produced dicentric chromosomes with two bridging arms connecting segregating centromeres as cells divide. This double bridge can break in mitosis. A genetic screen recovered chromosomes that were linearized by breakage in the male germline. Because the screen required viability of males with this X chromosome, the breakpoints in each arm of the double bridge must be closely matched to produce a nearly euploid chromosome. We expected that most linear chromosomes would be broken in heterochromatin because there are no vital genes in heterochromatin, and breakpoint distribution would be relatively unconstrained. Surprisingly, approximately half the breakpoints are found in euchromatin, and the breakpoints are clustered in just a few regions of the chromosome that closely match regions identified as intercalary heterochromatin. The results support the Laird hypothesis that intercalary heterochromatin can explain fragile sites in mitotic chromosomes, including fragile X. Opened rings also were recovered after male larvae were exposed to X-rays. This method was much less efficient and produced chromosomes with a strikingly different array of breakpoints, with almost all located in heterochromatin. A series of circularly permuted linear X chromosomes was generated that may be useful for investigating aspects of chromosome behavior, such as crossover distribution and interference in meiosis, or questions of nuclear organization and function.

  6. Lack of significant association between spina bifida and the fragile X syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Schiano, C.M. [United Cerebral Palsy of Nassau County, Roosevelt, NY (United States); Demb, H.B. [Albert Einstein College of Medicine, Bronx, NY (United States); Brown, W.T. [Inst. for Basic Research, Staten Island, NY (United States)

    1995-12-04

    Folic acid is involved in two common disorders associated with developmental disabilities. Spina bifida is a malformation that may be associated with mental retardation, learning disabilities, and epilepsy. Its incidence can be reduced by the ingestion of folic acid before, and at the time of, conception. The fragile X syndrome is a genetic disorder which is the most common form of inherited mental retardation. This disorder can be diagnosed by the induction of fragile sites on the X chromosome which is cultured in a medium deficient in folic acid. In several studies, folic acid was reported to alleviate some of the developmental and behavioral manifestations associated in the fragile X syndrome, while in others, it has no effect. 9 refs.

  7. Fragile Elite

    DEFF Research Database (Denmark)

    Bregnbæk, Susanne

    in China. It uncovers the intimate psychological strains students suffer under the pressure imposed on them by parents and state, where the state acts as a parent, and the parents sometimes reinforce the state. The book offers insights into the intergenerational tensions as work in relation to the ongoing......China's One Child Policy and its rigorous national focus on educational testing are well known. But what happens to those "lucky" few at the very top of the pyramid? Fragile Elite explores the contradictions of being an elite student through ethnographic research conducted at two top universities...... shifts in educational policy and definition of what a "quality" student, child, and citizen is in contemporary China....

  8. Identification of E. coli K12 chromosomal insertion sites of bacteriophage φ297

    Institute of Scientific and Technical Information of China (English)

    ZHAI Jing; CAO Qi-zhi; CHANG Wei-shan

    2005-01-01

    Objective:To identify the specific integration site of prophage φ297 in the host of E. coli K12 chromosome. Methods:Using molecular techniques such as Siebert PCR for walking from the int gene of prophage 297, which is similar to that of phage 933W to an unknown region in genomic DNA. A special adaptor is ligated to the ends of DNA fragments generated by digestion of genomic DNA with restriction enzymes that generates blunt ended fragments. Clone and subclone of PCR products, DNA sequencing and data analysis were used in this study. Results:The attL, attR and the core sequences were determined. The bacterial attachment site of phage φ297 was located in the yecE gene of E. coli K12. Conclusion:The phage φ297 integrates into the yecE gene of the E. coli K12 genome.

  9. The bacterial chromosome segregation protein Spo0J spreads along DNA from parS nucleation sites.

    Science.gov (United States)

    Murray, Heath; Ferreira, Henrique; Errington, Jeff

    2006-09-01

    Regulation of chromosome inheritance is essential to ensure proper transmission of genetic information. To accomplish accurate genome segregation, cells organize their chromosomes and actively separate them prior to cytokinesis. In Bacillus subtilis the Spo0J protein is required for accurate chromosome segregation and it regulates the developmental switch from vegetative growth to sporulation. Spo0J is a DNA-binding protein that recognizes at least eight identified parS sites located near the origin of replication. As judged by fluorescence microscopy, Spo0J forms discrete foci associated with the oriC region of the chromosome throughout the cell cycle. In an attempt to determine the mechanisms utilized by Spo0J to facilitate productive chromosome segregation, we have investigated the DNA binding activity of Spo0J. In vivo we find Spo0J associates with several kilobases of DNA flanking its specific binding sites (parS) through a parS-dependent nucleation event that promotes lateral spreading of Spo0J along the chromosome. Using purified components we find that Spo0J has the ability to coat non-specific DNA substrates. These 'Spo0J domains' provide large structures near oriC that could potentially demark, organize or localize the origin region of the chromosome.

  10. Integration sites of Epstein-Barr virus genome on chromosomes of human lymphoblastoid cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Wuu, K.D.; Chen, Y.J.; Wang-Wuu, S. [Institute of Genetics, Taipei (Taiwan, Province of China)

    1994-09-01

    Epstein-Barr virus (EBV) is the pathogen of infectious mononucleosis. The viral genome is present in more than 95% of the African cases of Burkitt lymphoma and it is usually maintained in episomal form in the tumor cells. Viral integration has been described only for Nanalwa which is a Burkitt lymphoma cell line lacking episomes. In order to examine the role of EBV in the immortalization of human Blymphocytes, we investigated whether the EBV integration into the human genome is essential. If the integration does occur, we would like to know whether the integration is randomly distributed or whether the viral DNA integrates preferentially at certain sites. Fourteen in vitro immortalized human lymphoblastoid cell lines (LCLs) were examined by fluorescence in situ hybridization (FISH) with a biotinylated EBV BamHI w DNA fragment as probe. The episomal form of EBV DNA was found in all cells of these cell lines, while only about 65% of the cells have the integrated viral DNA. This might suggest that integration is not a pre-requisite for cell immortalization. Although all chromosomes, except Y, have been found with integrated viral genome, chromsomes 1 and 5 are the most frequent EBV DNA carrier (p<0.05). Nine chromosome bands, namely, 1p31, 1q31, 2q32, 3q13, 3q26, 5q14, 6q24, 7q31 and 12q21, are preferential targets for EBV integration (p<0.001). Eighty percent of the total 938 EBV hybridization signals were found to be at G-band-positive area. This suggests that the mechanism of EBV integration might be different from that of the retroviruses, which specifically integrate to G-band-negative areas. Thus, we conclude that the integration of EBV to host genome is non-random and it may have something to do with the structure of chromosome and DNA sequences.

  11. Escherichia coli frameshift mutation rate depends on the chromosomal context but not on the GATC content near the mutation site.

    Science.gov (United States)

    Martina, Mariana A; Correa, Elisa M E; Argaraña, Carlos E; Barra, José L

    2012-01-01

    Different studies have suggested that mutation rate varies at different positions in the genome. In this work we analyzed if the chromosomal context and/or the presence of GATC sites can affect the frameshift mutation rate in the Escherichia coli genome. We show that in a mismatch repair deficient background, a condition where the mutation rate reflects the fidelity of the DNA polymerization process, the frameshift mutation rate could vary up to four times among different chromosomal contexts. Furthermore, the mismatch repair efficiency could vary up to eight times when compared at different chromosomal locations, indicating that detection and/or repair of frameshift events also depends on the chromosomal context. Also, GATC sequences have been proved to be essential for the correct functioning of the E. coli mismatch repair system. Using bacteriophage heteroduplexes molecules it has been shown that GATC influence the mismatch repair efficiency in a distance- and number-dependent manner, being almost nonfunctional when GATC sequences are located at 1 kb or more from the mutation site. Interestingly, we found that in E. coli genomic DNA the mismatch repair system can efficiently function even if the nearest GATC sequence is located more than 2 kb away from the mutation site. The results presented in this work show that even though frameshift mutations can be efficiently generated and/or repaired anywhere in the genome, these processes can be modulated by the chromosomal context that surrounds the mutation site.

  12. Escherichia coli frameshift mutation rate depends on the chromosomal context but not on the GATC content near the mutation site.

    Directory of Open Access Journals (Sweden)

    Mariana A Martina

    Full Text Available Different studies have suggested that mutation rate varies at different positions in the genome. In this work we analyzed if the chromosomal context and/or the presence of GATC sites can affect the frameshift mutation rate in the Escherichia coli genome. We show that in a mismatch repair deficient background, a condition where the mutation rate reflects the fidelity of the DNA polymerization process, the frameshift mutation rate could vary up to four times among different chromosomal contexts. Furthermore, the mismatch repair efficiency could vary up to eight times when compared at different chromosomal locations, indicating that detection and/or repair of frameshift events also depends on the chromosomal context. Also, GATC sequences have been proved to be essential for the correct functioning of the E. coli mismatch repair system. Using bacteriophage heteroduplexes molecules it has been shown that GATC influence the mismatch repair efficiency in a distance- and number-dependent manner, being almost nonfunctional when GATC sequences are located at 1 kb or more from the mutation site. Interestingly, we found that in E. coli genomic DNA the mismatch repair system can efficiently function even if the nearest GATC sequence is located more than 2 kb away from the mutation site. The results presented in this work show that even though frameshift mutations can be efficiently generated and/or repaired anywhere in the genome, these processes can be modulated by the chromosomal context that surrounds the mutation site.

  13. Chromosome 22q a frequent site of allele loss in head and neck carcinoma

    DEFF Research Database (Denmark)

    Poli-Frederico, R C; Bergamo, N A; Reis, P P;

    2000-01-01

    BACKGROUND: Loss of heterozygosity (LOH) correlates with inactivated tumor suppressor genes. LOH at chromosome arm 22q has been found in a variety of human neoplasms, suggesting that this region contains a tumor suppressor gene(s) other than NF2 important to tumorigenesis. The aim of this study...... tumor samples taken at the time of surgical treatment were evaluated for LOH by use of four microsatellite markers mapping to 22q11.2-q13. Clinical information was available for all patients. The frequency and distribution of LOH was correlated with clinical (age, sex, use of tobacco and alcohol, site...... gene (TSG) and involved in upper aerodigestive tract carcinogenesis. In particular, laryngeal tumors may harbor another putative TSG on 22q11.2-q12.3 that may play a role in aggressive stage III/IV disease....

  14. Fragile X Syndrome

    Science.gov (United States)

    Fragile X syndrome is the most common form of inherited developmental disability. A problem with a specific gene causes ... the protein. This causes the symptoms of Fragile X. People with only a small change in the ...

  15. Genetics Home Reference: fragile X syndrome

    Science.gov (United States)

    ... Van Esch H. The Fragile X premutation: new insights and clinical consequences. Eur J Med Genet. 2006 ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...

  16. A fragile X male with a broad smear on southern blot analysis representing 100-500 CGG repeats and no methylation at the EagI site of the FMR-1 gene

    Energy Technology Data Exchange (ETDEWEB)

    Lachiewicz, A.M.; Spiridigliozzi, G.A.; McConkie-Rosell, A. [Duke Univ. Medical Center, Durham, NC (United States)] [and others

    1996-08-09

    Fragile X DNA studies were carried out on all obligate carriers of a large fragile X family with 10 mentally retarded individuals. One 64-year-old carrier man with an altered FMR-1 allele was not described as being mentally retarded or as having any limitations in function. He was married, raised 8 children, and worked as an auto mechanic. On examination, he had macrocephaly and mild macroorchidism but few of the other typical physical findings of males with fragile X syndrome. His Full Scale IQ is 73, and his Vineland Adaptive Behavior Composite is 73. On the Woodcock-Johnson Psycho-Educational Battery-Revised, he achieved standard scores of 64 in Reading, 55 in Math, and 83 in Knowledge. His DNA findings showed a broad smear on Southern blot analysis of 100-500 CGG repeats and no methylation at the EagI site upstream of the FMR-1 protein coding region. His FMR-1 protein production is 12% of normal. His daughters all have large premutations, with somatic instability in the size of the CGG repeat lengths. They all have evidence of academic underachievement and 2 have physical characteristics frequently described in individuals with fragile X. 21 refs., 3 figs.

  17. DNA deformability changes of single base pair mutants within CDE binding sites in S. Cerevisiae centromere DNA correlate with measured chromosomal loss rates and CDE binding site symmetries

    Directory of Open Access Journals (Sweden)

    Marx Kenneth A

    2006-03-01

    Full Text Available Abstract Background The centromeres in yeast (S. cerevisiae are organized by short DNA sequences (125 bp on each chromosome consisting of 2 conserved elements: CDEI and CDEIII spaced by a CDEII region. CDEI and CDEIII are critical sequence specific protein binding sites necessary for correct centromere formation and following assembly with proteins, are positioned near each other on a specialized nucleosome. Hegemann et al. BioEssays 1993, 15: 451–460 reported single base DNA mutants within the critical CDEI and CDEIII binding sites on the centromere of chromosome 6 and quantitated centromere loss of function, which they measured as loss rates for the different chromosome 6 mutants during cell division. Olson et al. Proc Natl Acad Sci USA 1998, 95: 11163–11168 reported the use of protein-DNA crystallography data to produce a DNA dinucleotide protein deformability energetic scale (PD-scale that describes local DNA deformability by sequence specific binding proteins. We have used the PD-scale to investigate the DNA sequence dependence of the yeast chromosome 6 mutants' loss rate data. Each single base mutant changes 2 PD-scale values at that changed base position relative to the wild type. In this study, we have utilized these mutants to demonstrate a correlation between the change in DNA deformability of the CDEI and CDEIII core sites and the overall experimentally measured chromosome loss rates of the chromosome 6 mutants. Results In the CDE I and CDEIII core binding regions an increase in the magnitude of change in deformability of chromosome 6 single base mutants with respect to the wild type correlates to an increase in the measured chromosome loss rate. These correlations were found to be significant relative to 105 Monte Carlo randomizations of the dinucleotide PD-scale applied to the same calculation. A net loss of deformability also tends to increase the loss rate. Binding site position specific, 4 data-point correlations were also

  18. Repeat-mediated genetic and epigenetic changes at the FMR1 locus in the Fragile X-related disorders

    Directory of Open Access Journals (Sweden)

    Karen eUsdin

    2014-07-01

    Full Text Available AbstractThe Fragile X-related disorders are a group of genetic conditions that include the neurodegenerative disorder, Fragile X-associated tremor and ataxia syndrome (FXTAS, the fertility disorder, Fragile X-associated primary ovarian insufficiency (FXPOI and the intellectual disability, Fragile X syndrome (FXS. The pathology in all these diseases is related to the number of CGG/CCG-repeats in the 5’ UTR of the FMR1 gene. The repeats are prone to continuous expansion and the increase in repeat number has paradoxical effects on gene expression increasing transcription on mid-sized alleles and decreasing it on longer ones. In some cases the repeats can simultaneously both increase FMR1 mRNA production and decrease the levels of the FMR1 gene product, FMRP. Since FXTAS and FXPOI result from the deleterious consequences of the expression of elevated levels of FMR1 mRNA and FXS is caused by reduced FMRP levels, the clinical picture is turning out to be more complex than once appreciated. Added complications are generated by the fact that increasing repeat numbers make the alleles somatically unstable, generating resulting in individuals sometimes having a complex mixture of different sized alleles. Furthermore, it has become apparent that the eponymous fragile site, once thought to be no more than a useful diagnostic criterion, may have clinical consequences for females who inherit chromosomes that express this site. This review will cover what is currently known about the mechanisms responsible for repeat instability, for the repeat-mediated epigenetic changes that affect expression of the FMR1 gene, and for chromosome fragility. It will also touch on what current and future options are for ameliorating some of these effects.

  19. Chromosome Mapping of 18S Ribosomal RNA Genes in Eleven Hypostomus Species (Siluriformes, Loricariidae): Diversity Analysis of the Sites.

    Science.gov (United States)

    Rubert, Marceléia; da Rosa, Renata; Zawadzki, Claudio H; Mariotto, Sandra; Moreira-Filho, Orlando; Giuliano-Caetano, Lucia

    2016-08-01

    We investigated the chromosomal distribution of 18S ribosomal DNA (rDNA) in different populations of 11 species of Hypostomus collected in important Brazilian basins, namely South Atlantic, Upper Paraná, and Paraguay applying the fluorescence in situ hybridization (FISH). Hypostomus cochliodon, Hypostomus commersoni, Hypostomus hermanni, Hypostomus regani, Hypostomus albopunctatus, Hypostomus paulinus, Hypostomus aff. paulinus, Hypostomus iheringii, and Hypostomus mutucae presented multiple 18S rDNA sites while Hypostomus strigaticeps and Hypostomus nigromaculatus exhibited a single pair of chromosomes with 18S rDNA sites. The studied species presented variations in the number and position of these sites. The results accomplished were similar to those obtained by the analysis of AgNORs, revealing the same interspecific variability. Each species exhibited distinctive patterns of AgNOR and 18S rDNA distribution, which can be considered cytogenetic markers in each species of the genus and help improve the discussions on the phylogeny of the group.

  20. The Caulobacter crescentus chromosome replication origin evolved two classes of weak DnaA binding sites.

    Science.gov (United States)

    Taylor, James A; Ouimet, Marie-Claude; Wargachuk, Richard; Marczynski, Gregory T

    2011-10-01

    The Caulobacter crescentus replication initiator DnaA and essential response regulator CtrA compete to control chromosome replication. The C. crescentus replication origin (Cori) contains five strong CtrA binding sites but only two apparent DnaA boxes, termed G-boxes (with a conserved second position G, TGATCCACA). Since clusters of DnaA boxes typify bacterial replication origins, this discrepancy suggested that C. crescentus DnaA recognizes different DNA sequences or compensates with novel DNA-binding proteins. We searched for novel DNA sites by scanning mutagenesis of the most conserved Cori DNA. Autonomous replication assays showed that G-boxes and novel W-boxes (TCCCCA) are essential for replication. Further analyses showed that C. crescentus DnaA binds G-boxes with moderate and W-boxes with very weak affinities significantly below DnaA's capacity for high-affinity Escherichia coli-boxes (TTATCCACA). Cori has five conserved W-boxes. Increasing W-box affinities increases or decreases autonomous replication depending on their strategic positions between the G-boxes. In vitro, CtrA binding displaces DnaA from proximal G-boxes and from distal W-boxes implying CtrA-DnaA competition and DnaA-DnaA cooperation between G-boxes and W-boxes. Similarly, during cell cycle progression, CtrA proteolysis coincides with DnaA binding to Cori. We also observe highly conserved W-boxes in other replication origins lacking E. coli-boxes. Therefore, strategically weak DnaA binding can be a general means of replication control.

  1. Fragile X Syndrome

    OpenAIRE

    Wilmar Saldarriaga; Flora Tassone; Laura Yuriko González-Teshima; Jose Vicente Forero-Forero; Sebastián Ayala-Zapata; Randi Hagerman

    2015-01-01

    Fragile X Syndrome (FXS) is a genetic disease due to a CGG trinucleotide expansion, named full mutation (greater than 200 CGG repeats), in the fragile X mental retardation 1 gene locus Xq27.3; which leads to an hypermethylated region in the gene promoter therefore silencing it and lowering the expression levels of the fragile X mental retardation 1, a protein involved in synaptic plasticity and maturation.  Individuals with FXS present with intellectual disability, autism, hyperactivity, long...

  2. NOR sites detected by Ag-dAPI staining of an unusual autosome chromosome of Bradysia hygida (Diptera:Sciaridae) colocalize with C-banded heterochromatic region.

    Science.gov (United States)

    Gaspar, Vanessa Pinatto; Borges, Alex Rodrigues; Fernandez, Maria Aparecida

    2002-01-01

    The study of chromosomes in insects is a good tool in mitotic process analysis, zoographic localization and evolution investigation. Among them, the Sciaridae offers a karyotype with a small number of chromosomes, where the heterochromatin and nucleolar organizer region, NOR, are easily analyzed in metaphase chromosomes obtained from cerebral ganglia squashes. In this work, the heterochromatic regions on Bradysia hygida mitotic chromosomes, revealed by C-banding, were identified as centromeric blocks on A and C chromosomes and as dark interstitial region in B and X chromosomes. By Ag-DAPI staining, active nucleolus organizer region, NOR, was revealed associated to the constitutive heterochromatin in the end of the C autosome chromosome. The C-band regions and the unusual ribosomal site localization are discussed.

  3. The two Cis-acting sites, parS1 and oriC1, contribute to the longitudinal organisation of Vibrio cholerae chromosome I.

    Science.gov (United States)

    David, Ariane; Demarre, Gaëlle; Muresan, Leila; Paly, Evelyne; Barre, François-Xavier; Possoz, Christophe

    2014-07-01

    The segregation of bacterial chromosomes follows a precise choreography of spatial organisation. It is initiated by the bipolar migration of the sister copies of the replication origin (ori). Most bacterial chromosomes contain a partition system (Par) with parS sites in close proximity to ori that contribute to the active mobilisation of the ori region towards the old pole. This is thought to result in a longitudinal chromosomal arrangement within the cell. In this study, we followed the duplication frequency and the cellular position of 19 Vibrio cholerae genome loci as a function of cell length. The genome of V. cholerae is divided between two chromosomes, chromosome I and II, which both contain a Par system. The ori region of chromosome I (oriI) is tethered to the old pole, whereas the ori region of chromosome II is found at midcell. Nevertheless, we found that both chromosomes adopted a longitudinal organisation. Chromosome I extended over the entire cell while chromosome II extended over the younger cell half. We further demonstrate that displacing parS sites away from the oriI region rotates the bulk of chromosome I. The only exception was the region where replication terminates, which still localised to the septum. However, the longitudinal arrangement of chromosome I persisted in Par mutants and, as was reported earlier, the ori region still localised towards the old pole. Finally, we show that the Par-independent longitudinal organisation and oriI polarity were perturbed by the introduction of a second origin. Taken together, these results suggest that the Par system is the major contributor to the longitudinal organisation of chromosome I but that the replication program also influences the arrangement of bacterial chromosomes.

  4. The two Cis-acting sites, parS1 and oriC1, contribute to the longitudinal organisation of Vibrio cholerae chromosome I.

    Directory of Open Access Journals (Sweden)

    Ariane David

    2014-07-01

    Full Text Available The segregation of bacterial chromosomes follows a precise choreography of spatial organisation. It is initiated by the bipolar migration of the sister copies of the replication origin (ori. Most bacterial chromosomes contain a partition system (Par with parS sites in close proximity to ori that contribute to the active mobilisation of the ori region towards the old pole. This is thought to result in a longitudinal chromosomal arrangement within the cell. In this study, we followed the duplication frequency and the cellular position of 19 Vibrio cholerae genome loci as a function of cell length. The genome of V. cholerae is divided between two chromosomes, chromosome I and II, which both contain a Par system. The ori region of chromosome I (oriI is tethered to the old pole, whereas the ori region of chromosome II is found at midcell. Nevertheless, we found that both chromosomes adopted a longitudinal organisation. Chromosome I extended over the entire cell while chromosome II extended over the younger cell half. We further demonstrate that displacing parS sites away from the oriI region rotates the bulk of chromosome I. The only exception was the region where replication terminates, which still localised to the septum. However, the longitudinal arrangement of chromosome I persisted in Par mutants and, as was reported earlier, the ori region still localised towards the old pole. Finally, we show that the Par-independent longitudinal organisation and oriI polarity were perturbed by the introduction of a second origin. Taken together, these results suggest that the Par system is the major contributor to the longitudinal organisation of chromosome I but that the replication program also influences the arrangement of bacterial chromosomes.

  5. Chromosomal mapping of repetitive DNAs in Gobionellus oceanicus and G. stomatus (Gobiidae; Perciformes): A shared XX/XY system and an unusual distribution of 5S rDNA sites on the Y chromosome.

    Science.gov (United States)

    Lima-Filho, Paulo A; Amorim, Karlla D J; Cioffi, Marcelo B; Bertollo, Luiz A C; Molina, Wagner F

    2014-01-01

    With nearly 2,000 species, Gobiidae is the most specious family of the vertebrates. This high level of speciation is accompanied by conspicuous karyotypic modifications, where the role of repetitive sequences remains largely unknown. This study analyzed the karyotype of 2 species of the genus Gobionellus and mapped 18S and 5S ribosomal RNA genes and (CA)15 microsatellite sequences onto their chromosomes. G. oceanicus (2n = 56; ♂ 12 metacentrics (m) + 4 submetacentrics (sm) + 1 subtelocentric (st) + 39 acrocentrics (a); ♀ 12m + 4sm + 2st + 38a) and G. stomatus (2n = 56; ♂ 20m + 14sm + 1st + 21a; ♀ 20m + 14sm + 2st + 20a) possess the highest diploid chromosome number among the Gobiidae and have different karyotypes. Both species share an XX/XY sex chromosome system with a large subtelocentric X and a small acrocentric Y chromosome which is rich in (CA)15 sequences and bears 5S rRNA sites. Although coding and noncoding repetitive DNA sequences may be involved in the genesis or differentiation of the sex chromosomes, the exclusive presence of 5S rDNA sites on the Y, but not on the X chromosome of both species, represents a novelty in fishes. In summary, the karyotypic differences, as well as new data on the sex chromosome systems in these 2 Gobiidae species, confirm the high chromosomal dynamism observed in this family.

  6. Genome-wide analysis of host-chromosome binding sites for Epstein-Barr Virus Nuclear Antigen 1 (EBNA1

    Directory of Open Access Journals (Sweden)

    Wang Pu

    2010-10-01

    Full Text Available Abstract The Epstein-Barr Virus (EBV Nuclear Antigen 1 (EBNA1 protein is required for the establishment of EBV latent infection in proliferating B-lymphocytes. EBNA1 is a multifunctional DNA-binding protein that stimulates DNA replication at the viral origin of plasmid replication (OriP, regulates transcription of viral and cellular genes, and tethers the viral episome to the cellular chromosome. EBNA1 also provides a survival function to B-lymphocytes, potentially through its ability to alter cellular gene expression. To better understand these various functions of EBNA1, we performed a genome-wide analysis of the viral and cellular DNA sites associated with EBNA1 protein in a latently infected Burkitt lymphoma B-cell line. Chromatin-immunoprecipitation (ChIP combined with massively parallel deep-sequencing (ChIP-Seq was used to identify cellular sites bound by EBNA1. Sites identified by ChIP-Seq were validated by conventional real-time PCR, and ChIP-Seq provided quantitative, high-resolution detection of the known EBNA1 binding sites on the EBV genome at OriP and Qp. We identified at least one cluster of unusually high-affinity EBNA1 binding sites on chromosome 11, between the divergent FAM55 D and FAM55B genes. A consensus for all cellular EBNA1 binding sites is distinct from those derived from the known viral binding sites, suggesting that some of these sites are indirectly bound by EBNA1. EBNA1 also bound close to the transcriptional start sites of a large number of cellular genes, including HDAC3, CDC7, and MAP3K1, which we show are positively regulated by EBNA1. EBNA1 binding sites were enriched in some repetitive elements, especially LINE 1 retrotransposons, and had weak correlations with histone modifications and ORC binding. We conclude that EBNA1 can interact with a large number of cellular genes and chromosomal loci in latently infected cells, but that these sites are likely to represent a complex ensemble of direct and indirect EBNA

  7. Recurring genomic breaks in independent lineages support genomic fragility

    Directory of Open Access Journals (Sweden)

    Hannenhalli Sridhar

    2006-11-01

    Full Text Available Abstract Background Recent findings indicate that evolutionary breaks in the genome are not randomly distributed, and that certain regions, so-called fragile regions, are predisposed to breakages. Previous approaches to the study of genomic fragility have examined the distribution of breaks, as well as the coincidence of breaks with segmental duplications and repeats, within a single species. In contrast, we investigate whether this regional fragility is an inherent genomic characteristic and is thus conserved over multiple independent lineages. Results We do this by quantifying the extent to which certain genomic regions are disrupted repeatedly in independent lineages. Our investigation, based on Human, Chimp, Mouse, Rat, Dog and Chicken, suggests that the propensity of a chromosomal region to break is significantly correlated among independent lineages, even when covariates are considered. Furthermore, the fragile regions are enriched for segmental duplications. Conclusion Based on a novel methodology, our work provides additional support for the existence of fragile regions.

  8. DNA tandem repeat instability in the Escherichia coli chromosome is stimulated by mismatch repair at an adjacent CAG·CTG trinucleotide repeat

    Science.gov (United States)

    Blackwood, John K.; Okely, Ewa A.; Zahra, Rabaab; Eykelenboom, John K.; Leach, David R. F.

    2010-01-01

    Approximately half the human genome is composed of repetitive DNA sequences classified into microsatellites, minisatellites, tandem repeats, and dispersed repeats. These repetitive sequences have coevolved within the genome but little is known about their potential interactions. Trinucleotide repeats (TNRs) are a subclass of microsatellites that are implicated in human disease. Expansion of CAG·CTG TNRs is responsible for Huntington disease, myotonic dystrophy, and a number of spinocerebellar ataxias. In yeast DNA double-strand break (DSB) formation has been proposed to be associated with instability and chromosome fragility at these sites and replication fork reversal (RFR) to be involved either in promoting or in preventing instability. However, the molecular basis for chromosome fragility of repetitive DNA remains poorly understood. Here we show that a CAG·CTG TNR array stimulates instability at a 275-bp tandem repeat located 6.3 kb away on the Escherichia coli chromosome. Remarkably, this stimulation is independent of both DNA double-strand break repair (DSBR) and RFR but is dependent on a functional mismatch repair (MMR) system. Our results provide a demonstration, in a simple model system, that MMR at one type of repetitive DNA has the potential to influence the stability of another. Furthermore, the mechanism of this stimulation places a limit on the universality of DSBR or RFR models of instability and chromosome fragility at CAG·CTG TNR sequences. Instead, our data suggest that explanations of chromosome fragility should encompass the possibility of chromosome gaps formed during MMR. PMID:21149728

  9. PID controllers' fragility.

    Science.gov (United States)

    Alfaro, Víctor M

    2007-10-01

    In this paper, an index for measuring fragility of proportional integral derivative (PID) controllers is proposed. This index relates the losses of robustness of the control loop when controller parameters change, to the nominal robustness of the control loop. Furthermore, it defines when a PID controller is fragile, nonfragile or resilient.

  10. Education and Fragile States

    Science.gov (United States)

    Kirk, Jackie

    2007-01-01

    Within the fragile states agendas and policies of development agencies and organisations education is of concern; education is a social service sector in which the impacts of state fragility are significant, in terms of access and quality of provision for children, working conditions and support for teachers, good governance and legitimacy for the…

  11. Event-related potential alterations in fragile X syndrome

    OpenAIRE

    Inga Sophia eKnoth; Sarah eLippe

    2012-01-01

    Fragile X Syndrome (FXS) is the most common form of X-linked intellectual disability, associated with a wide range of cognitive and behavioural impairments. FXS is caused by a trinucleotide repeat expansion in the FMR1 gene located on the X-chromosome. FMR1 is expected to prevent the expression of the fragile X mental retardation protein (FMRP), which results in altered structural and functional development of the synapse, including a loss of synaptic plasticity. This review aims to unveil th...

  12. Mapping and ordered cloning of the human X chromosome

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, C.T.; Nelson, D.L.

    1992-12-01

    Progress is reported on gathering X chromosome specific libraries and integrating those with the library produced in this project. Further studies on understanding Fragile X Syndrome and other hereditary diseases related to the X chromosome are described. (DT)

  13. Fragile X founder effects and new mutations in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, N.; Smits, B.; Curley, D. [New York State Inst. for Basic Research in Developmental Disabilities, Staten Island, NY (United States)] [and others

    1996-07-12

    The apparent associations between fragile X mutations and nearby microsatellites may reflect both founder effects and microsatellite instability. To gain further insight into their relative contributions, we typed a sample of 56 unrelated control and 37 fragile X chromosomes from an eastern Finnish population for FMR1 CGG repeat lengths, AGG interspersion patterns, DXS548, FRAXAC1, FRAXE and a new polymorphic locus, Alu-L. In the controls, the most common FMR1 allele was 30 repeats with a range of 20 to 47 and a calculated heterozygosity of 88%. A strong founder effect was observed for locus DXS548 with 95% of fragile X chromosomes having the 21 CA repeat (196 bp) allele compared to 17% of controls, while none of the fragile X but 69% of controls had the 20 repeat allele. Analysis of the combined loci DXS548-FRAXAC1-FRAXE showed three founder haplotypes. Haplotype 21-19-16 was found on 27 (75%) of fragile X chromosomes but on none of controls. Three (8.4%) fragile X chromosomes had haplotypes 21-19-15, 21-19-20, and 21-19-25 differing from the common fragile X haplotype only in FRAXE. These could have arisen by recombination or from mutations of FRAXE. A second haplotype 21-18-17 was found in four (11.1%) fragile X chromosomes but only one (1.9%) control. This may represent a more recent founder mutation. A third haplotype 25-21-15, seen in two fragile X chromosomes (5.6%) and one (1.9%) control, was even less common and thus may represent an even more recent mutation or admixture of immigrant types. Analysis of the AGG interspersions within the FMR1 CGG repeat showed that 7/8 premutation chromosomes lacked an AGG whereas all controls had at least one AGG. This supports the hypothesis that the mutation of AGG to CGG leads to repeat instability and mutational expansion. 43 refs., 3 figs., 7 tabs.

  14. A chromosomal breakage syndrome with profound immunodeficiency.

    Science.gov (United States)

    Conley, M E; Spinner, N B; Emanuel, B S; Nowell, P C; Nichols, W W

    1986-05-01

    The chromosomal breakage syndromes--ataxia-telangiectasia, Fanconi's anemia, and Bloom's syndrome--are associated with growth failure, neurologic abnormalities, immunodeficiency, and an increased incidence of malignancy. The relationship between these features is unknown. We recently evaluated a 21-year-old female with more severe chromosomal breakage, immunodeficiency, and growth failure than in any of the mentioned disorders. As of November 1985, the patient remains clinically free of malignancy. At age 18, the patient's weight was 22.6 kg (50th percentile for seven years), height was 129 cm (50th percentile for eight years), and head circumference was 42 cm (50th percentile for six months). Laboratory studies demonstrated a marked decrease in both B and T cell number and function. The peripheral blood contained 400 to 900 lymphocytes/microL with 32% T11 cells, 17% T4 cells, and 21% T8 cells. The proliferative responses to phytohemagglutinin (PHA), pokeweed mitogen, and concanavalin A were less than 10% of control. There were 1% surface IgM positive cells, and serum IgG was 185 mg/dL, IgM 7 mg/dL, IgA 5 mg/dL. In lymphocyte cultures stimulated with the T cell mitogens PHA, phorbol ester, and interleukin 2, 55% of the banded metaphases demonstrated breaks or rearrangements. The majority of the breaks involved four fragile sites on chromosomes 7 and 14, 7p13, 7q35, 14q11, and 14q32. These are the sites of the genes for the T cell-antigen receptor and the immunoglobulin heavy chain and are sites of gene rearrangement in lymphocyte differentiation. Epstein-Barr virus stimulated B cells and fibroblast cultures also demonstrated a high incidence of breaks, but the sites were less selective. These findings suggest that the sites of chromosomal fragility in the chromosomal breakage syndromes may be informative and that factors other than the severity of the immunodeficiency or the high incidence of chromosomal damage may contribute to the occurrence of malignancy in the

  15. Stress induced by premature chromatin condensation triggers chromosome shattering and chromothripsis at DNA sites still replicating in micronuclei or multinucleate cells when primary nuclei enter mitosis.

    Science.gov (United States)

    Terzoudi, Georgia I; Karakosta, Maria; Pantelias, Antonio; Hatzi, Vasiliki I; Karachristou, Ioanna; Pantelias, Gabriel

    2015-11-01

    Combination of next-generation DNA sequencing, single nucleotide polymorphism array analyses and bioinformatics has revealed the striking phenomenon of chromothripsis, described as complex genomic rearrangements acquired in a single catastrophic event affecting one or a few chromosomes. Via an unproven mechanism, it is postulated that mechanical stress causes chromosome shattering into small lengths of DNA, which are then randomly reassembled by DNA repair machinery. Chromothripsis is currently examined as an alternative mechanism of oncogenesis, in contrast to the present paradigm that considers a stepwise development of cancer. While evidence for the mechanism(s) underlying chromosome shattering during cancer development remains elusive, a number of hypotheses have been proposed to explain chromothripsis, including ionizing radiation, DNA replication stress, breakage-fusion-bridge cycles, micronuclei formation and premature chromosome compaction. In the present work, we provide experimental evidence on the mechanistic basis of chromothripsis and on how chromosomes can get locally shattered in a single catastrophic event. Considering the dynamic nature of chromatin nucleoprotein complex, capable of rapid unfolding, disassembling, assembling and refolding, we first show that chromatin condensation at repairing or replicating DNA sites induces the mechanical stress needed for chromosome shattering to ensue. Premature chromosome condensation is then used to visualize the dynamic nature of interphase chromatin and demonstrate that such mechanical stress and chromosome shattering can also occur in chromosomes within micronuclei or asynchronous multinucleate cells when primary nuclei enter mitosis. Following an aberrant mitosis, chromosomes could find themselves in the wrong place at the wrong time so that they may undergo massive DNA breakage and rearrangement in a single catastrophic event. Specifically, our results support the hypothesis that premature chromosome

  16. 2′-Deoxyriboguanylurea, the primary breakdown product of 5-aza-2′-deoxyribocytidine, is a mutagen, an epimutagen, an inhibitor of DNA methyltransferases and an inducer of 5-azacytidine-type fragile sites

    Science.gov (United States)

    Lamparska, Katarzyna; Clark, Jarrod; Babilonia, Gail; Bedell, Victoria; Yip, Wesley; Smith, Steven S.

    2012-01-01

    5-Aza-2′-deoxycytidine (5azaC-dR) has been employed as an inhibitor of DNA methylation, a chemotherapeutic agent, a clastogen, a mutagen, an inducer of fragile sites and a carcinogen. However, its effects are difficult to quantify because it rapidly breaks down in aqueous solution to the stable compound 2′-deoxyriboguanylurea (GuaUre-dR). Here, we used a phosphoramidite that permits the introduction of GuaUre-dR at defined positions in synthetic oligodeoxynucleotides to demonstrate that it is a potent inhibitor of human DNA methyltransferase 1 (hDNMT1) and the bacterial DNA methyltransferase (M.EcoRII) and that it is a mutagen that can form productive base pairs with either Guanine or Cytosine. Pure GuaUre-dR was found to be an effective demethylating agent and was able to induce 5azaC-dR type fragile sites FRA1J and FRA9E in human cells. Moreover, we report that demethylation associated with C:G → G:C transversion and C:G → T:A transition mutations was observed in human cells exposed to pure GuaUre-dR. The data suggest that most of the effects attributed to 5azaC-dR are exhibited by its stable primary breakdown product. PMID:22850746

  17. 2'-Deoxyriboguanylurea, the primary breakdown product of 5-aza-2'-deoxyribocytidine, is a mutagen, an epimutagen, an inhibitor of DNA methyltransferases and an inducer of 5-azacytidine-type fragile sites.

    Science.gov (United States)

    Lamparska, Katarzyna; Clark, Jarrod; Babilonia, Gail; Bedell, Victoria; Yip, Wesley; Smith, Steven S

    2012-10-01

    5-Aza-2'-deoxycytidine (5azaC-dR) has been employed as an inhibitor of DNA methylation, a chemotherapeutic agent, a clastogen, a mutagen, an inducer of fragile sites and a carcinogen. However, its effects are difficult to quantify because it rapidly breaks down in aqueous solution to the stable compound 2'-deoxyriboguanylurea (GuaUre-dR). Here, we used a phosphoramidite that permits the introduction of GuaUre-dR at defined positions in synthetic oligodeoxynucleotides to demonstrate that it is a potent inhibitor of human DNA methyltransferase 1 (hDNMT1) and the bacterial DNA methyltransferase (M.EcoRII) and that it is a mutagen that can form productive base pairs with either Guanine or Cytosine. Pure GuaUre-dR was found to be an effective demethylating agent and was able to induce 5azaC-dR type fragile sites FRA1J and FRA9E in human cells. Moreover, we report that demethylation associated with C:G → G:C transversion and C:G → T:A transition mutations was observed in human cells exposed to pure GuaUre-dR. The data suggest that most of the effects attributed to 5azaC-dR are exhibited by its stable primary breakdown product.

  18. Trio Fragile / Olga Kaljundi

    Index Scriptorium Estoniae

    Kaljundi, Olga, 1941-2001

    1998-01-01

    Tallinna Vene Draamateatri galeriis esinenud trupi "Trio Fragile" vernissaazhist. Trio loomingust ja osalejatest : kahe muusiku seltskonnas esineb ka 1984.a. Kunstiülikooli lõpetanud kunstnik Tõnu Talve.

  19. Karyotyping and in situ chromosomal localization of rDNA sites in black cumin Bunium persicum (Boiss B. Fedtsch,1915 (Apiaceae

    Directory of Open Access Journals (Sweden)

    R. K. Chahota

    2011-11-01

    Full Text Available The fluorescent in situ hybridization (FISH technique has been applied to somatic chromosomes in the medicinally important species, Bunium persicum, to elucidate its karyotypes. The bicolour FISH technique involving 18S-5.8S-26S and 5S ribosomal RNA genes as probes was used to assign physical localization and measurement of rDNA sites on homologous pairs of chromosomes. The two 18S-5.8S-26S rRNA gene sites were at the terminal regions of the short arms of the chromosomes 1 and 2 involving NOR region of chromosome 1. The 5S rDNA sites were found on subtelomeric region of the long arm of the chromosome number 5 and at interstitial regions of the short arm of chromosome 7. Based on direct visual analysis of chromosome length, morphology and position of FISH signals, a pioneer attempt has been made to construct metaphase karyotype in B. persicum, an endangered medicinal plant of North Western Himalayas.

  20. Ocular Motor Indicators of Executive Dysfunction in Fragile X and Turner Syndromes

    Science.gov (United States)

    Lasker, Adrian G.; Mazzocco, Michele M. M.; Zee, David S.

    2007-01-01

    Fragile X and Turner syndromes are two X-chromosome-related disorders associated with executive function and visual spatial deficits. In the present study, we used ocular motor paradigms to examine evidence that disruption to different neurological pathways underlies these deficits. We tested 17 females with fragile X, 19 females with Turner…

  1. Identification of the SlmA active site responsible for blocking bacterial cytokinetic ring assembly over the chromosome.

    Directory of Open Access Journals (Sweden)

    Hongbaek Cho

    Full Text Available Bacterial cells use chromosome-associated division inhibitors to help coordinate the processes of DNA replication and segregation with cytokinesis. SlmA from Escherichia coli, a member of the tetracycline repressor (TetR-like protein family, is one example of this class of regulator. It blocks the assembly of the bacterial cytokinetic ring by interfering with the polymerization of the tubulin-like FtsZ protein in a manner that is dramatically stimulated upon specific DNA binding. Here we used a combination of molecular genetics and biochemistry to identify the active site of SlmA responsible for disrupting FtsZ polymerization. Interestingly, this site maps to a region of SlmA that in the published DNA-free structure is partially occluded by the DNA-binding domains. In this conformation, the SlmA structure resembles the drug/inducer-bound conformers of other TetR-like proteins, which in the absence of inducer require an inward rotation of their DNA-binding domains to bind successive major grooves on operator DNA. Our results are therefore consistent with a model in which DNA-binding activates SlmA by promoting a rotational movement of the DNA-binding domains that fully exposes the FtsZ-binding sites. SlmA may thus represent a special subclass of TetR-like proteins that have adapted conformational changes normally associated with inducer sensing in order to modulate an interaction with a partner protein. In this case, the adaptation ensures that SlmA only blocks cytokinesis in regions of the cell occupied by the origin-proximal portion of the chromosome where SlmA-binding sites are enriched.

  2. Jumping translocation in acute monocytic leukemia (M5b) with alternative breakpoint sites in the long arm of donor chromosome 3.

    Science.gov (United States)

    McGrattan, Peter; Logan, Amy; Humphreys, Mervyn; Bowers, Margaret

    2010-09-01

    An 86-year-old man presented with acute hepatic failure, worsening thrombocytopenia, and anemia having been diagnosed and managed expectantly with cytogenetically normal RAEB-1. After 20 months a diagnosis of disease transformation to acute monocytic leukemia (M5b) was made. Conventional G-banded analysis of unstimulated bone marrow cultures demonstrated a jumping translocation (JT) involving proximal and distal breakpoints on donor chromosome 3 at bands 3q1?2 and 3q21, respectively. Recipient chromosomes included the long-arm telomeric regions of chromosomes 5, 10, 14, 16, and 19. A low-level trisomy 8 clone was also found in association with both proximal and distal JT clones. Conventional G-banded analysis of unstimulated peripheral blood cultures detected the proximal 3q1?2 JT clone involving recipient chromosome 10 several weeks after transformation to acute monocytic leukemia. Interestingly, JTs involving recipient chromosomes 5, 14, 16, and 19 were not detected in this peripheral blood sample. Palliative care was administered until his demise 2.2 months after disease transformation. There have been fewer than 70 cases of acquired JTs reported in the literature, including one myeloproliferative neoplasm and five acute myeloid leukemias involving a single breakpoint site on donor chromosome 3. Our case is unique as it is the first acquired case to demonstrate a JT involving alternative pericentromeric breakpoint sites on a single donor chromosome consisting of a proximal breakpoint at 3q1?2 and a more distal breakpoint at 3q21.

  3. Repetitive, Marker-Free, Site-Specific Integration as a Novel Tool for Multiple Chromosomal Integration of DNA

    DEFF Research Database (Denmark)

    Petersen, Kia Vest; Martinussen, Jan; Jensen, Peter Ruhdal

    2013-01-01

    We present a tool for repetitive, marker-free, site-specific integration in Lactococcus lactis, in which a nonreplicating plasmid vector (pKV6) carrying a phage attachment site (attP) can be integrated into a bacterial attachment site (attB). The novelty of the tool described here is the inclusion...... of a minimal bacterial attachment site (attBmin), two mutated loxP sequences (lox66 and lox71) allowing for removal of undesirable vector elements (antibiotic resistance marker), and a counterselection marker (oroP) for selection of loxP recombination on the pKV6 vector. When transformed into L. lactis...... expressing the phage TP901-1 integrase, pKV6 integrates with high frequency into the chromosome, where it is flanked by attL and attR hybrid attachment sites. After expression of Cre recombinase from a plasmid that is not able to replicate in L. lactis, loxP recombinants can be selected for by using 5...

  4. Fragile X syndrome in two siblings with major congenital malformations

    Energy Technology Data Exchange (ETDEWEB)

    Giampietro, P.F.; Haas, B.R.; Lipper, E. [Cornell Univ. Medical Center, New York, NY (United States)] [and others

    1996-05-17

    We report on 2 brothers with both fragile X and VACTERL-H syndrome. The first sibling, age 5, had bilateral cleft lip and palate, ventricular septal defect, and a hypoplastic thumb. The second sibling, age 2{1/2}, had a trachesophageal fistula, esophageal atresia, and vertebral abnormality. High-resolution chromosome analysis showed a 46,XY chromosome constitution in both siblings. By PCR and Southern blot analysis, the siblings were found to have large triplet repeat expansions in the fragile X gene (FMR 1) and both had methylation mosaicism. Enzyme kinetic studies of iduronate sulfatase demonstrated a two-fold increase in activity in the first sib as compared to the second. Possible mechanisms through which the fragile X mutation can cause down-regulation of adjacent loci are discussed. 24 refs., 4 figs.

  5. Reverse mutations in the fragile X syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.T.; Houck, G.E. Jr.; Ding, Xiaohua [New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States)

    1996-08-09

    Three females were identified who have apparent reversal of fragile X premutations. Based on haplotype analysis of nearby markers, they were found to have inherited a fragile X chromosome from their premutation carrier mothers, and yet had normal size FMR1 repeat alleles. The changes in repeat sizes from mother to daughter was 95 to 35 in the first, 145 to 43 in the second, and 82 to 33 in the third. In the first family, mutations of the nearby microsatellites FRAXAC2 and DXS548 were also observed. In the other two, only mutations involving the FMR1 repeats were found. We suggest differing mutational mechanisms such as gene conversion versus DNA replication slippage may underlie such reversions. We estimate that such revertants may occur among 1% or less of premutation carrier offspring. Our results indicate that women identified to be carriers by linkage should be retested by direct DNA analysis. 35 refs., 5 figs.

  6. Fragile X Syndrome--From Genes to Cognition

    Science.gov (United States)

    Schneider, A.; Hagerman, R. J.; Hessl, D.

    2009-01-01

    Fragile X syndrome (FXS), a single gene disorder with an expanded CGG allele on the X chromosome, is the most common form of inherited cognitive impairment. The cognitive deficit ranges from mild learning disabilities to severe intellectual disability. The phenotype includes hyperactivity, short attention span, emotional problems including…

  7. The Neuroanatomy and Neuroendocrinology of Fragile X Syndrome

    Science.gov (United States)

    Hessl, David; Rivera, Susan M.; Reiss, Allan L.

    2004-01-01

    Fragile X syndrome (FXS), caused by a single gene mutation on the X chromosome, offers a unique opportunity for investigation of gene-brain-behavior relationships. Recent advances in molecular genetics, human brain imaging, and behavioral studies have started to unravel the complex pathways leading to the cognitive, psychiatric, and physical…

  8. Differentially Expressed Genes Distributed Over Chromosomes and Implicated in Certain Biological Processes for Site Insertion Genetically Modified Rice Kemingdao

    Directory of Open Access Journals (Sweden)

    Zhi Liu, Yunhe Li, Jie Zhao, Xiuping Chen, Guiliang Jian, Yufa Peng, Fangjun Qi

    2012-01-01

    Full Text Available Release of genetically modified (GM plants has sparked off intensive debates worldwide partly because of concerns about potential adverse unintended effects of GM plants to the agro system and the safety of foods. In this study, with the aim of revealing the molecular basis for unintended effects of a single site insertion GM Kemingdao (KMD rice transformed with a synthetic cry1Ab gene, and bridging unintended effects of KMD rice through clues of differentially expressed genes, comparative transcriptome analyses were performed for GM KMD rice and its parent rice of Xiushui11 (XS11. The results showed that 680 differentially expressed transcripts were identified from 30-day old seedlings of GM KMD rice. The absolute majority of these changed expression transcripts dispersed and located over all rice chromosomes, and existed physical distance on chromosome from the insertion site, while only two transcripts were found to be differentially expressed within the 21 genes located within 100 kb up and down-stream of the insertion site. Pathway and biology function analyses further revealed that differentially expressed transcripts of KMD rice were involved in certain biological processes, and mainly implicated in two types of pathways. One type was pathways implicated in plant stress/defense responses, which were considerably in coordination with the reported unintended effects of KMD rice, which were more susceptible to rice diseases compared to its parent rice XS11; the other type was pathways associated with amino acids metabolism. With this clue, new unintended effects for changes in amino acids synthesis of KMD rice leaves were successfully revealed. Such that an actual case was firstly provided for identification of unintended effects in GM plants by comparative transciptome analysis.

  9. Role of SV40 Integration Site at Chromosomal Interval 1q21.1 in Immortalized CRL2504 Cells

    Science.gov (United States)

    Liu, Jinglan; Kaur, Gurpreet; Zhawar, Vikramjit K.; Zimonjic, Drazen B.; Popescu, Nicholas C.; Kandpal, Raj P.; Athwal, Raghbir S.

    2009-01-01

    We have applied a functional gene transfer strategy to demonstrate the importance of viral integration site in cellular immortalization. The large tumor antigen of SV40 is capable of extending the cellular life span by sequestering tumor suppressor proteins pRB and p53 in virus-transformed human cells. Although SV40-LT is essential, it is not sufficient for cellular immortalization, suggesting that additional alterations in cellular genes are required to attain infinite proliferation. We demonstrate here that the disruption of human chromosomal interval at 1q21.1, by SV40 integration, can be an essential step for cellular immortalization. The transfer of a 150Kb bacterial artificial chromosome (BAC) clone, RP364B14, corresponding to viral integration site in CRL2504 cells, reverted their immortal phenotype. Interestingly, the BAC transfer clones of CRL-2504 cells displayed characteristics of either senescence as shown by β-galactosidase activity or apoptosis as revealed by positive staining with M30 cytoDeath antibody. The SV40 integration at 1q21.1, in the vicinity of epidermal differentiation complex genes, resulted in the down-regulation of the filaggrin (FLG) gene that is part of the epidermal differentiation complex. FLG gene expression was restored to its normal levels in BAC transfer senescent and apoptotic clones. Our results suggest that the disruption of native genomic sequence by SV40 may alter expression of genes involved in senescence and apoptosis by modulating chromatin structure. These studies imply that identification of genes located in the vicinity of viral integration sites in human cancers may be helpful in developing new diagnostic and therapeutic strategies. PMID:19789346

  10. Hair root FMRP expression for screening of fragile X full mutation females

    OpenAIRE

    Lantip Rujito; Dwi Kustiani; Lies Anne Severijnen; Peter Hanzon; Sultana MH Faradz; Rob Willemsen

    2016-01-01

    The fragile X syndrome is the most common form of inherited mental retardation in humans, caused by an expansion of the cytosine-guanine-guanine (CGG) repeat in the fragile X mental retardation 1 (FMR1) gene located on the X chromosome. Antibody tests have been developed to identify fragile X patients, based on the presence or absence of fragile mental retardation protein (FMRP) in both lymphocytes and hair roots. The objective of this study was to compare correlations of hair root and lympho...

  11. Total body irradiation in a patient with fragile X syndrome for acute lymphoblastic leukemia in preparation for stem cell transplantation: A case report and literature review.

    Science.gov (United States)

    Collins, D T; Mannina, E M; Mendonca, M

    2015-10-01

    Fragile X syndrome (FXS) is a congenital disorder caused by expansion of CGG trinucleotide repeat at the 5' end of the fragile X mental retardation gene 1 (FMR1) on the X chromosome that leads to chromosomal instability and diminished serum levels of fragile X mental retardation protein (FMRP). Afflicted individuals often have elongated features, marfanoid habitus, macroorchidism and intellectual impairment. Evolving literature suggests the condition may actually protect from malignancy while chromosomal instability would presumably elevate the risk. Increased sensitivity to ionizing radiation should also be predicted by unstable sites within the DNA. Interestingly, in this report, we detail a patient with FXS diagnosed with acute lymphoblastic leukemia treated with induction followed by subsequent cycles of hyper-CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone) with a complete response who then was recommended to undergo peripheral stem cell transplantation. The patient underwent total body irradiation (TBI) as a component of his conditioning regimen and despite the concern of his clinicians, developed minimal acute toxicity and successful engraftment. The pertinent literature regarding irradiation of patients with FXS is also reviewed.

  12. Karyotype characterization of Crotalaria juncea (L. by chromosome banding and physical mapping of 18S-5.8S-26S and 5S rRNA gene sites

    Directory of Open Access Journals (Sweden)

    Mateus Mondin

    2007-01-01

    Full Text Available The chromosomes of Crotalaria juncea, a legume of agronomic interest with a 2n = 16 karyotype composed of metacentric chromosomes, were analyzed using several cytogenetic techniques. C-banding revealed heterochromatic regions around the centromeres in all chromosomes and adjacent to the secondary constriction on the chromosome 1 short arm. Fluorescent staining with the GC-specific chromomycin A3 (CMA highlighted these heterochromatic regions and a tiny site on the chromosome 1 long arm while the AT-specific stain 4'-6-diamidino-2-phenylindole (DAPI induced a reversed pattern. Staining with CMA combined with AT-specific distamycin A (DA counterstaining quenched the pericentromeric regions of all chromosomes, but enhanced fluorescence was observed at the heterochromatic regions around the secondary constriction and on the long arms of chromosomes 1 and 4. Fluorescence in situ hybridization (FISH revealed 18S-5.8S-26S rRNA gene sites (45S rDNA on chromosomes 1 and 4, and one 5S rDNA locus on chromosome 1. All the rDNA sites were co-located with the positive-CMA/DA bands, suggesting they were very rich in GC. Silver staining revealed signals at the main 45S rDNA locus on chromosome 1 and, in some cells, chromosome 4 was labeled. Two small nucleoli were detected in a few interphase cells, suggesting that the minor site on chromosome 4 could be active at some stages of the cell cycle.

  13. DNA double-strand breaks coupled with PARP1 and HNRNPA2B1 binding sites flank coordinately expressed domains in human chromosomes.

    Directory of Open Access Journals (Sweden)

    Nickolai A Tchurikov

    2013-04-01

    Full Text Available Genome instability plays a key role in multiple biological processes and diseases, including cancer. Genome-wide mapping of DNA double-strand breaks (DSBs is important for understanding both chromosomal architecture and specific chromosomal regions at DSBs. We developed a method for precise genome-wide mapping of blunt-ended DSBs in human chromosomes, and observed non-random fragmentation and DSB hot spots. These hot spots are scattered along chromosomes and delimit protected 50-250 kb DNA domains. We found that about 30% of the domains (denoted forum domains possess coordinately expressed genes and that PARP1 and HNRNPA2B1 specifically bind DNA sequences at the forum domain termini. Thus, our data suggest a novel type of gene regulation: a coordinated transcription or silencing of gene clusters delimited by DSB hot spots as well as PARP1 and HNRNPa2B1 binding sites.

  14. Component fragility research program

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, N.C.; Mochizuki, G.L.; Holman, G.S. (NCT Engineering, Inc., Lafayette, CA (USA); Lawrence Livermore National Lab., CA (USA))

    1989-11-01

    To demonstrate how high-level'' qualification test data can be used to estimate the ultimate seismic capacity of nuclear power plant equipment, we assessed in detail various electrical components tested by the Pacific Gas Electric Company for its Diablo Canyon plant. As part of our Phase I Component Fragility Research Program, we evaluated seismic fragility for five Diablo Canyon components: medium-voltage (4kV) switchgear; safeguard relay board; emergency light battery pack; potential transformer; and station battery and racks. This report discusses our Phase II fragility evaluation of a single Westinghouse Type W motor control center column, a fan cooler motor controller, and three local starters at the Diablo Canyon nuclear power plant. These components were seismically qualified by means of biaxial random motion tests on a shaker table, and the test response spectra formed the basis for the estimate of the seismic capacity of the components. The seismic capacity of each component is referenced to the zero period acceleration (ZPA) and, in our Phase II study only, to the average spectral acceleration (ASA) of the motion at its base. For the motor control center, the seismic capacity was compared to the capacity of a Westinghouse Five-Star MCC subjected to actual fragility tests by LLNL during the Phase I Component Fragility Research Program, and to generic capacities developed by the Brookhaven National Laboratory for motor control center. Except for the medium-voltage switchgear, all of the components considered in both our Phase I and Phase II evaluations were qualified in their standard commercial configurations or with only relatively minor modifications such as top bracing of cabinets. 8 refs., 67 figs., 7 tabs.

  15. BONE FRAGILITY IN TURNER SYNDROME: MECHANISMS AND PREVENTION STRATEGIES

    Directory of Open Access Journals (Sweden)

    Maria Felicia Faienza

    2016-04-01

    Full Text Available Bone fragility is recognized as one of major comorbidities in Turner Syndrome (TS. The mechanisms underlying bone impairment in affected patients are not clearly elucidated, but estrogen deficiency and X-chromosomal abnormalities represent important factors. Moreover, although many girls with TS undergo recombinant growth hormone (rGH therapy to treat short stature, the efficacy of this treatment on BMD is controversial. The present review will focus on bone fragility in subjects with TS, providing an overview on the pathogenic mechanisms and some prevention strategies.

  16. Event-related potential alterations in fragile X syndrome

    OpenAIRE

    Knoth, Inga S.; Lippé, Sarah

    2012-01-01

    Fragile X Syndrome (FXS) is the most common form of X-linked intellectual disability (ID), associated with a wide range of cognitive and behavioral impairments. FXS is caused by a trinucleotide repeat expansion in the FMR1 gene located on the X-chromosome. FMR1 is expected to prevent the expression of the “fragile X mental retardation protein (FMRP)”, which results in altered structural and functional development of the synapse, including a loss of synaptic plasticity. This review aims to unv...

  17. Bone Fragility in Turner Syndrome: Mechanisms and Prevention Strategies.

    Science.gov (United States)

    Faienza, Maria Felicia; Ventura, Annamaria; Colucci, Silvia; Cavallo, Luciano; Grano, Maria; Brunetti, Giacomina

    2016-01-01

    Bone fragility is recognized as one of the major comorbidities in Turner syndrome (TS). The mechanisms underlying bone impairment in affected patients are not clearly elucidated, but estrogen deficiency and X-chromosomal abnormalities represent important factors. Moreover, although many girls with TS undergo recombinant growth hormone therapy to treat short stature, the efficacy of this treatment on bone mineral density is controversial. The present review will focus on bone fragility in subjects with TS, providing an overview on the pathogenic mechanisms and some prevention strategies.

  18. Discriminatory profile of rDNA sites and trend for acrocentric chromosome formation in the genus Trachinotus Lacépède, 1801 (Perciformes, Carangidae

    Directory of Open Access Journals (Sweden)

    Uedson Jacobina

    2012-10-01

    Full Text Available Chromosomal traits have provided valuable information for phylogeny and taxonomy of several fish groups. Three Atlantic Carangidae species of the genus Trachinotus Lacépède, 1801 (T. goodei Jordan et Evermann, 1896, T. carolinus (Linnaeus, 1766 and T. falcatus (Linnaeus, 1758 were investigated,2n=48 chromosomes but different chromosomal arms (FN number, i.e., 52, 56 and 58, respectively, in view of the different number of two-armed chromosomes found in their karyotypes. Thus, T. goodei, T. carolinus and T. falcatus present a progressive distance from the probable basal karyotype proposed for Perciformes (2n=48 acrocentrics, FN=48. At first sight, these findings do not agree with the phylogenetic hypothesis based on mitochondrial sequences, where T. goodei appear as the most derived species, followed by T. falcatus and T. carolinus, respectively. However, the chromosomal mapping of ribosomal DNAs was informative for clarifying this apparent conflict. Indeed, the multiple 5S and 18S rDNA sites found in T. goodei corroborate the most derived condition for this species. In this sense, the occurrence of the unexpected number of two-armed chromosomes and FN value for this species, as well as for T. carolinus, must be due to additional rounds of acrocentric formation in these species, modifying the macrostructure of their karyotypes.

  19. Mapping and ordered cloning of the human X chromosome. Progress report, September 1991--November 1992

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, C.T.; Nelson, D.L.

    1992-12-01

    Progress is reported on gathering X chromosome specific libraries and integrating those with the library produced in this project. Further studies on understanding Fragile X Syndrome and other hereditary diseases related to the X chromosome are described. (DT)

  20. Site-specific deletions of chromosomally located DNA segments with the multimer resolution system of broad-host-range plasmid RP4

    DEFF Research Database (Denmark)

    Sternberg, Claus; Eberl, Leo; Sanchezromero, Juan M.

    1995-01-01

    The multimer resolution system (mrs) of the broad-host-range plasmid RP4 has been exploited to develop a general method that permits the precise excision of chromosomal segments in a variety of gram-negative bacteria. The procedure is based on the site-specific recombination between two directly ...

  1. Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Wilmar Saldarriaga

    2015-01-01

    Full Text Available Fragile X Syndrome (FXS is a genetic disease due to a CGG trinucleotide expansion, named full mutation (greater than 200 CGG repeats, in the fragile X mental retardation 1 gene locus Xq27.3; which leads to an hypermethylated region in the gene promoter therefore silencing it and lowering the expression levels of the fragile X mental retardation 1, a protein involved in synaptic plasticity and maturation.  Individuals with FXS present with intellectual disability, autism, hyperactivity, long face, large or prominent ears and macroorchidism at puberty and thereafter. Most of the young children with FXS will present with language delay, sensory hyper arousal and anxiety. Girls are less affected than boys, only 25% have intellectual disability. Given the genomic features of the syndrome, there are patients with a number of triplet repeats between 55 and 200, known as premutation carriers. Most carriers have a normal IQ but some have developmental problems. The diagnosis of FXS has evolved from karyotype with special culture medium, to molecular techniques that are more sensitive and specific including PCR and Southern Blot. During the last decade, the advances in the knowledge of FXS, has led to the development of investigations on pharmaceutical management or targeted treatments for FXS. Minocycline and sertraline have shown efficacy in children.

  2. The cHS4 insulator increases the probability of retroviral expression at random chromosomal integration sites.

    Science.gov (United States)

    Rivella, S; Callegari, J A; May, C; Tan, C W; Sadelain, M

    2000-05-01

    Retroviruses are highly susceptible to transcriptional silencing and position effects imparted by chromosomal sequences at their integration site. These phenomena hamper the use of recombinant retroviruses as stable gene delivery vectors. As insulators are able to block promoter-enhancer interactions and reduce position effects in some transgenic animals, we examined the effect of an insulator on the expression and structure of randomly integrated recombinant retroviruses. We used the cHS4 element, an insulator from the chicken beta-like globin gene cluster, which has been shown to reduce position effects in transgenic Drosophila. A large panel of mouse erythroleukemia cells that bear a single copy of integrated recombinant retroviruses was generated without using drug selection. We show that the cHS4 increases the probability that integrated proviruses will express and dramatically decreases the level of de novo methylation of the 5' long terminal repeat. These findings support a primary role of methylation in the silencing of retroviruses and suggest that cHS4 could be useful in gene therapy applications to overcome silencing of retroviral vectors.

  3. An A-T linker adapter polymerase chain reaction method for chromosome walking without restriction site cloning bias.

    Science.gov (United States)

    Trinh, Quoclinh; Xu, Wentao; Shi, Hui; Luo, Yunbo; Huang, Kunlun

    2012-06-01

    A-T linker adapter polymerase chain reaction (PCR) was modified and employed for the isolation of genomic fragments adjacent to a known DNA sequence. The improvements in the method focus on two points. The first is the modification of the PO(4) and NH(2) groups in the adapter to inhibit the self-ligation of the adapter or the generation of nonspecific products. The second improvement is the use of the capacity of rTaq DNA polymerase to add an adenosine overhang at the 3' ends of digested DNA to suppress self-ligation in the digested DNA and simultaneously resolve restriction site clone bias. The combination of modifications in the adapter and in the digested DNA leads to T/A-specific ligation, which enhances the flexibility of this method and makes it feasible to use many different restriction enzymes with a single adapter. This novel A-T linker adapter PCR overcomes the inherent limitations of the original ligation-mediated PCR method such as low specificity and a lack of restriction enzyme choice. Moreover, this method also offers higher amplification efficiency, greater flexibility, and easier manipulation compared with other PCR methods for chromosome walking. Experimental results from 143 Arabidopsis mutants illustrate that this method is reliable and efficient in high-throughput experiments.

  4. Expansion of GA Dinucleotide Repeats Increases the Density of CLAMP Binding Sites on the X-Chromosome to Promote Drosophila Dosage Compensation.

    Directory of Open Access Journals (Sweden)

    Guray Kuzu

    2016-07-01

    Full Text Available Dosage compensation is an essential process that equalizes transcript levels of X-linked genes between sexes by forming a domain of coordinated gene expression. Throughout the evolution of Diptera, many different X-chromosomes acquired the ability to be dosage compensated. Once each newly evolved X-chromosome is targeted for dosage compensation in XY males, its active genes are upregulated two-fold to equalize gene expression with XX females. In Drosophila melanogaster, the CLAMP zinc finger protein links the dosage compensation complex to the X-chromosome. However, the mechanism for X-chromosome identification has remained unknown. Here, we combine biochemical, genomic and evolutionary approaches to reveal that expansion of GA-dinucleotide repeats likely accumulated on the X-chromosome over evolutionary time to increase the density of CLAMP binding sites, thereby driving the evolution of dosage compensation. Overall, we present new insight into how subtle changes in genomic architecture, such as expansions of a simple sequence repeat, promote the evolution of coordinated gene expression.

  5. A new insight into fragile X syndrome among Basque population.

    Science.gov (United States)

    Peñagarikano, Olga; Gil, Alberto; Télez, Mercedes; Ortega, Begoña; Flores, Piedad; Veiga, Isabel; Peixoto, Ana; Criado, Begoña; Arrieta, Isabel

    2004-07-30

    The expansion of a trinucleotide repeat [CGG]n located in the FMR1 X-linked gene is the main cause of fragile X syndrome, the most common form of inherited mental retardation. We have analyzed the factors known, to date, to influence the instability of the repeat in 158 normal X chromosomes from the Spanish Basque population. These factors included length of the repeat, AGG interspersion pattern, length of uninterrupted CGG and DXS548-FRAXAC1 markers associated haplotype. Previous investigations on Basques showed an absence of this disorder among mentally retarded individuals that was likely due to a low prevalence of large CGG alleles and the presence of AGG interruptions on them. The present report suggests that, although the frequency of large alleles is low and they do maintain AGG interruptions, different mutational pathways that might lead to fragile X syndrome could be occurring among Basques. These pathways mainly include alleles with internal sequences 9 + 9 + n and 9 + 12 + 9 that show fragile X associated haplotypes. Besides, the lack of the most proximal AGG interruption, proposed recently as a novel factor involved in CGG repeat instability, was highly identified among alleles with long pure CGG tracts, which showed an internal sequence n + 9. The data suggest that, despite the lower incidence of large alleles, the prevalence of potentially unstable alleles among Basques is similar to that of other Caucasian populations and that these alleles could become fragile X chromosomes.

  6. Proximity Within Interphase Chromosome Contributes to the Breakpoint Distribution in Radiation-Induced Intrachromosomal Exchanges

    Science.gov (United States)

    Zhang, Ye; Uhlemeyer, Jimmy; Hada, Megumi; Asaithamby, A.; Chen, David J.; Wu, Honglu

    2015-01-01

    Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome3 in human mammary epithelial cells after exposures to either low-or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations. Further investigations suggest that the 3D chromosome folding is cell type and culture condition dependent.

  7. Modeling fragile X syndrome in the Fmr1 knockout mouse

    OpenAIRE

    Kazdoba, Tatiana M.; Leach, Prescott T.; Silverman, Jill L.; Crawley, Jacqueline N

    2014-01-01

    Fragile X Syndrome (FXS) is a commonly inherited form of intellectual disability and one of the leading genetic causes for autism spectrum disorder. Clinical symptoms of FXS can include impaired cognition, anxiety, hyperactivity, social phobia, and repetitive behaviors. FXS is caused by a CGG repeat mutation which expands a region on the X chromosome containing the FMR1 gene. In FXS, a full mutation (> 200 repeats) leads to hypermethylation of FMR1, an epigenetic mechanism that effectively si...

  8. DNA topoisomerases participate in fragility of the oncogene RET.

    Directory of Open Access Journals (Sweden)

    Laura W Dillon

    Full Text Available Fragile site breakage was previously shown to result in rearrangement of the RET oncogene, resembling the rearrangements found in thyroid cancer. Common fragile sites are specific regions of the genome with a high susceptibility to DNA breakage under conditions that partially inhibit DNA replication, and often coincide with genes deleted, amplified, or rearranged in cancer. While a substantial amount of work has been performed investigating DNA repair and cell cycle checkpoint proteins vital for maintaining stability at fragile sites, little is known about the initial events leading to DNA breakage at these sites. The purpose of this study was to investigate these initial events through the detection of aphidicolin (APH-induced DNA breakage within the RET oncogene, in which 144 APH-induced DNA breakpoints were mapped on the nucleotide level in human thyroid cells within intron 11 of RET, the breakpoint cluster region found in patients. These breakpoints were located at or near DNA topoisomerase I and/or II predicted cleavage sites, as well as at DNA secondary structural features recognized and preferentially cleaved by DNA topoisomerases I and II. Co-treatment of thyroid cells with APH and the topoisomerase catalytic inhibitors, betulinic acid and merbarone, significantly decreased APH-induced fragile site breakage within RET intron 11 and within the common fragile site FRA3B. These data demonstrate that DNA topoisomerases I and II are involved in initiating APH-induced common fragile site breakage at RET, and may engage the recognition of DNA secondary structures formed during perturbed DNA replication.

  9. Mechanisms of telomere loss and their consequences for chromosome instability

    Directory of Open Access Journals (Sweden)

    Keiko eMuraki

    2012-10-01

    Full Text Available The ends of chromosomes in mammals, called telomeres, are composed of a 6 base pair repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.

  10. Fragile X gene instability: Anchoring AGGs and linked microsatellites

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Nan; Yang, Weihong; Dobkin, C. [Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States)] [and others

    1995-08-01

    Interspersed AGGs within the FMR1 gene CGG repeat region may anchor the sequence and prevent slippage during replication. In order to detect the AGG position variations, we developed a method employing partial MnlI restriction analysis and analyzed X chromosomes from 187 males, including 133 normal controls (17 with 20-34 and 16 with 35-52 repeats), plus 54 fragile X premutations with 56-180 repeats. Among controls, the interspersed AGG positions were highly polymorphic, with heterozygosity of 91%. Among the control samples, 1.5% had no AGG positions, 25% had one, 71% had two, and 3% had three. Among the fragile X premutation samples, 63% had no AGG, while 37% had only one AGG. Analysis of premutation samples within fragile X families showed that variation occurred only within the 3{prime} end of the region. Thus, the instability was polar. Controls with {ge}15 pure CGG repeats were associated with the longest alleles of two nearby microsatellites, FRAXAC1 with 20-21 repeats and DXS548 with 202-206 bp and with increased microsatellite heterzygosity. The association of long pure CGG regions, as with fragile X chromosomes, with the longer and more heterozygous microsatellite alleles suggests they may be related mechanistically. Further, our results do not support a recent suggestion that the frequency of fragile X alleles may be increasing. Finally, analysis of a set of nonhuman primate samples showed that long pure CGG tracks are variable in size and are located within the 3{prime} region, which suggests that polar instability within FMR1 is evolutionarily quite old. 55 refs., 3 figs., 4 tabs.

  11. Relating Fragile States to Social and Human Fragilities

    OpenAIRE

    Dubois, Jean-Luc; Huyghebaert , Patricia

    2009-01-01

    Fragile States is a way of naming this particular category of states that have weak performance, insufficient service delivery, weak administrative and government power, and lack of legal rules. Little consideration is usually made to the fact that their own societies may also be fragile and easily jeopardised by inappropriate economic measures or external events. Poverty traps and social exclusion, unjust inequalities with lack of equity, feelings of insecurity and vulnerability, usually und...

  12. Reverse mutation in fragile X syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Antinolo, G.; Borrego, S.; Cabeza, J.C. [Hospital Universitario, Sevilla (Spain)] [and others

    1996-01-01

    The fragile X syndrome is the most common cause of familial mental retardation, with an incidence of {approximately}1/1,500 in males and 1/2,500 in females. The clinical expression includes moderate to severe mental retardation, macroorchidism, dysmorphic facial features and behavior disturbances. In 1991, the FMR-1 gene was isolated from the region of the fragile X site. The fragile X phenotype has been found, in most cases, to be characterized at the molecular level by expansion of a (CGG){sub n} repeat and hypermethylation of a CpG island identified in the 5{prime}-UTR of the FMR-1 gene. It has been proposed, and some evidence has been shown, that germ cells carry only premutation alleles and that expansion occurs at a postzygotic stage. A few cases of reduction of the (CGG){sub n} repeat in fragile X syndrome have been reported. These reductions were from a larger premutation to a smaller premutation, in female-to-male transmission, from full mutation to a mosaic pattern, reduction from mosaic full-mutation/premutation females or regression from premutation to normal. We present here the novel observation of a phenotypically normal female carrying a nonmosaic full-mutation allele in somatic cells who transmits a premutation allele to her daughter. This daughter has three mosaic offspring with the full mutation and the premutation. Two of them are monozygotic (MZ) twins sharing a concordant mutation pattern. They are monoamniotic monochorionic, which indicates a late form of twinning. 20 refs., 1 fig.

  13. Repetitive genome elements in a European corn borer, Ostrinia nubilalis, bacterial artificial chromosome library were indicated by bacterial artificial chromosome end sequencing and development of sequence tag site markers: implications for lepidopteran genomic research.

    Science.gov (United States)

    Coates, Brad S; Sumerford, Douglas V; Hellmich, Richard L; Lewis, Leslie C

    2009-01-01

    The European corn borer, Ostrinia nubilalis, is a serious pest of food, fiber, and biofuel crops in Europe, North America, and Asia and a model system for insect olfaction and speciation. A bacterial artificial chromosome library constructed for O. nubilalis contains 36 864 clones with an estimated average insert size of >or=120 kb and genome coverage of 8.8-fold. Screening OnB1 clones comprising approximately 2.76 genome equivalents determined the physical position of 24 sequence tag site markers, including markers linked to ecologically important and Bacillus thuringiensis toxin resistance traits. OnB1 bacterial artificial chromosome end sequence reads (GenBank dbGSS accessions ET217010 to ET217273) showed homology to annotated genes or expressed sequence tags and identified repetitive genome elements, O. nubilalis miniature subterminal inverted repeat transposable elements (OnMITE01 and OnMITE02), and ezi-like long interspersed nuclear elements. Mobility of OnMITE01 was demonstrated by the presence or absence in O. nubilalis of introns at two different loci. A (GTCT)n tetranucleotide repeat at the 5' ends of OnMITE01 and OnMITE02 are evidence for transposon-mediated movement of lepidopteran microsatellite loci. The number of repetitive elements in lepidopteran genomes will affect genome assembly and marker development. Single-locus sequence tag site markers described here have downstream application for integration within linkage maps and comparative genomic studies.

  14. International Companies in Fragile States

    DEFF Research Database (Denmark)

    Patey, Luke; Kragelund, Peter

    Denmark must not fail to promote corporate social responsibility in fragile states. International companies remain active in these environments, and often worsen rather than alleviate poor governance. Financial transparency and human rights initiatives offer the first step in ensuring...

  15. Microsatellite and single nucleotide polymorphisms in the β-globin locus control region-hypersensitive Site 2: SPECIFICITY of Tunisian βs chromosomes.

    Science.gov (United States)

    Ben Mustapha, Maha; Moumni, Imen; Zorai, Amine; Douzi, Kaïs; Ghanem, Abderraouf; Abbes, Salem

    2012-01-01

    The diversity of sickle cell disease severity is attributed to several cis acting factors, among them the single nucleotide polymorphisms (SNPs) and (AT) rich region in the β-locus control region (β-LCR). This contains five DNase I hypersensitive sites (HS) located 6 to 22 kb upstream to the ϵ gene. The most important of these is the HS2 (5' β-LCR-HS2), characterized by the presence of three different SNPs and a microsatellite region known to be in association with β(S) chromosomes in various populations. The aim of this study was to present the molecular investigation of the 5' β-LCR-HS2 site in normal and sickle cell disease individuals in order to determine if there is any correlation or specificity between these molecular markers, the β(S) Tunisian chromosomes and phenotypical expression of sickle cell disease. One hundred and twenty-four chromosomes from Tunisian individuals (49 β(S) carriers and 13 normal individuals) were screened by polymerase chain reaction (PCR) and sequencing for the polymorphic short tandem microsatellite repeats (AT)(X)N(12)(AT)(Y) and the three SNPs (rs7119428, rs9736333 and rs60240093) of the 5' β-LCR-HS2. Twelve configurations of the microsatellite motif were found with an ancestral configuration elaborated by ClustalW software. Normal and mutated alleles were observed at the homozygous and heterozygous states for the three SNPs. Correlation between microsatellites and SNPs suggests that mutant SNP alleles were mainly associated, in the homozygous sickle cell disease phenotype, with the (AT)(8)N(12)GT(AT)(7) configuration, whereas, normal SNP alleles were associated with the (AT)(X)N(12)(AT)(11) configurations in normal β(A) chromosomes. The correlation of these various configurations with Hb F expression was also investigated. The principal component analysis (PCA) showed the correlation between the homozygous sickle cell disease phenotype, mutated SNP alleles and the Benin microsatellite configuration (AT)(8)N(12)GT

  16. Stability, fragility, and Rota's Conjecture

    NARCIS (Netherlands)

    Mayhew, D.; Whittle, G.; Zwam, S.H.M. van

    2010-01-01

    Fix a matroid N. A matroid M is N-fragile if, for each element e of M, at least one of M\\e and M/e has no N-minor. The Bounded Canopy Conjecture is that all GF(q)-representable matroids M that have an N-minor and are N-fragile have branch width bounded by a constant depending only on q and N. A matr

  17. Stability, fragility, and Rota's Conjecture

    NARCIS (Netherlands)

    Mayhew, D.; Whittle, G.; Zwam, S.H.M. van

    2011-01-01

    Fix a matroid N. A matroid M is N-fragile if, for each element e of M, at least one of M\\e and M/e has no N-minor. The Bounded Canopy Conjecture is that all GF(q)-representable matroids M that have an N-minor and are N-fragile have branch width bounded by a constant depending only on q and N. A matr

  18. Mapping Self-Reports of Working Memory Deficits to Executive Dysfunction in Fragile X Mental Retardation 1 ("FMR1") Gene Premutation Carriers Asymptomatic for FXTAS

    Science.gov (United States)

    Kogan, Cary S.; Cornish, Kim M.

    2010-01-01

    Fragile X Syndrome is a neurodevelopmental disorder that is caused by the silencing of a single gene on the X chromosome, the Fragile X Mental Retardation 1 ("FMR1") gene. In recent years, the premutation ("carrier") status has received considerable attention and there is now an emerging consensus that despite intellectual functioning being within…

  19. Handbook of nuclear power plant seismic fragilities, Seismic Safety Margins Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Cover, L.E.; Bohn, M.P.; Campbell, R.D.; Wesley, D.A.

    1983-12-01

    The Seismic Safety Margins Research Program (SSMRP) has a gola to develop a complete fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. As part of this program, calculations of the seismic risk from a typical commercial nuclear reactor were made. These calculations required a knowledge of the probability of failure (fragility) of safety-related components in the reactor system which actively participate in the hypothesized accident scenarios. This report describes the development of the required fragility relations and the data sources and data reduction techniques upon which they are based. Both building and component fragilities are covered. The building fragilities are for the Zion Unit 1 reactor which was the specific plant used for development of methodology in the program. Some of the component fragilities are site-specific also, but most would be usable for other sites as well.

  20. Site-specific integration of the temperate bacteriophage phi adh into the Lactobacillus gasseri chromosome and molecular characterization of the phage (attP) and bacterial (attB) attachment sites.

    Science.gov (United States)

    Raya, R R; Fremaux, C; De Antoni, G L; Klaenhammer, T R

    1992-01-01

    The temperate bacteriophage phi adh integrates its genome into the chromosomal DNA of Lactobacillus gasseri ADH by a site-specific recombination process. Southern hybridization analysis of BclI-digested genomic DNA from six relysogenized derivatives of the prophage-cured strain NCK102 displayed phage-chromosomal junction fragments identical to those of the lysogenic parent. The phi adh attachment site sequence, attP, was located within a 365-bp EcoRI-HindIII fragment of phage phi adh. This fragment was cloned and sequenced. DNA sequence analysis revealed striking features common to the attachment sites of other site-specific recombination systems: five direct repeats of the sequence TGTCCCTTTT(C/T) and a 14-bp inverted repeat. Oligonucleotides derived from the sequence of the attP-containing fragment enabled us to amplify predicted junction fragment sequences and thus to identify attL, attR, and attB. The core region was defined as the 16-bp sequence TACACTTCTTAGGAGG. Phage-encoded functions essential for site-specific insertion of phage phi adh were located in a 4.5-kb BclI fragment. This fragment was cloned in plasmid pSA34 to generate the insertional vector pTRK182. Plasmid pTRK182 was introduced into L. gasseri NCK102 by electroporation. Hybridization analysis showed that a single copy of pTRK182 had integrated at the attB site of the NCK102 erythromycin-resistant transformants. This is the first site-specific recombination system described in lactobacilli, as well as the first attP-based site-specific integration vector constructed for L. gasseri ADH. Images PMID:1512192

  1. Deletion of PTEN Produces Deficits in Conditioned Fear and Increases Fragile X Mental Retardation Protein

    Science.gov (United States)

    Lugo, Joaquin N.; Smith, Gregory D.; Morrison, Jessica B.; White, Jessika

    2013-01-01

    The phosphatase and tensin homolog detected on chromosome 10 (PTEN) gene product modulates activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. The PI3K pathway has been found to be involved in the regulation of the fragile X mental retardation protein, which is important for long-term depression and in the formation of new…

  2. Chondromyxoid fibroma of rib with a novel chromosomal translocation: a report of four additional cases at unusual sites

    Directory of Open Access Journals (Sweden)

    Parwani Anil V

    2007-11-01

    Full Text Available Abstract Background Chondromyxoid fibromas (CMFs are rare benign chondroid/myxoid matrix-producing tumors that occur in metaphyses of long tubular bones, and very rarely in small bones of hands and feet. Flat bone involvement is even more uncommon. Prior cytogenetic analyses have identified complex abnormalities involving chromosome 6 in the majority of cases. Methods A search for CMF over an 8-year period (1999–2006 from the surgical pathology files of our institution yielded 16 cases. Four cases occurred in relatively unusual regions, three from the small bones of distal extremities and one from the rib. The rib lesion wassubmitted forroutinecytogenetic analysis. Results Radiographic studies revealed that all four lesions were well-defined expansile radiolucent lesions which expanded the bony cortices with lobulated margins, sclerotic rim, septation, and no calcification. Morphologically, all four lesions showed typical features of CMF and had low proliferative index with Ki-67. Cytogenetic analysis on the rib lesion revealed a novel chromosomal translocation, t(1;5(p13;p13. None of the four patients had a recurrence after a mean duration of follow-up of 24 months. Conclusion CMF originating in unusual locations should be distinguished from chondrosarcomas, especially on small biopsies, and should be included in the differential diagnosis. As previously noted in the literature, the cells can be positive for actin but unlike conventional chondroid neoplasms can be negative for S-100. To our knowledge, this is the first report describing a novel chromosomal translocation, t(1;5(p13;p13 in CMF.

  3. Autism Spectrum Disorder and Fragile X Syndrome

    Science.gov (United States)

    ... Just Figuring Out CGG Repeats! Donate Print PDF Autism Spectrum Disorder and Fragile X Syndrome Fragile X ... known single gene cause of ASD What Is Autism Spectrum Disorder? Read my Story Autism spectrum disorder ( ...

  4. Learning to deliver education in fragile states

    Directory of Open Access Journals (Sweden)

    Martin Greeley

    2006-07-01

    Full Text Available The Fragile States Group within the Development AssistanceCommittee (DAC of the Organisation for EconomicCooperation and Development is working to advise donors onprovision of education (and other services in ‘fragile states’.

  5. Concurrence of fragile X syndrome and 47, XYY in an individual with a Prader-Willi-like phenotype.

    Science.gov (United States)

    Stalker, Heather J; Keller, Kory L; Gray, Brian A; Zori, Roberto T

    2003-01-15

    We report on a 34-year-old developmentally disabled man referred to our clinic for evaluation of possible Prader-Willi syndrome on the basis of obesity and voracious appetite. Cytogenetic and molecular analysis revealed a 47, XYY karyotype and the presence of a trinucleotide repeat expansion resulting in fragile X syndrome. To our knowledge, this is the first report of concurrence of XYY and fragile X syndrome in the medical literature. Review of sex chromosome abnormalities associated with fragile X syndrome and phenotypic considerations are presented.

  6. Marker chromosomes.

    Science.gov (United States)

    Rao, Kiran Prabhaker; Belogolovkin, Victoria

    2013-04-01

    Marker chromosomes are a morphologically heterogeneous group of structurally abnormal chromosomes that pose a significant challenge in prenatal diagnosis. Phenotypes associated with marker chromosomes are highly variable and range from normal to severely abnormal. Clinical outcomes are very difficult to predict when marker chromosomes are detected prenatally. In this review, we outline the classification, etiology, cytogenetic characterization, and clinical consequences of marker chromosomes, as well as practical approaches to prenatal diagnosis and genetic counseling.

  7. Improved recombinant antibody production by CHO cells using a production enhancer DNA element with repeated transgene integration at a predetermined chromosomal site.

    Science.gov (United States)

    Kawabe, Yoshinori; Inao, Takanori; Komatsu, Shodai; Huang, Guan; Ito, Akira; Omasa, Takeshi; Kamihira, Masamichi

    2017-03-01

    Chinese hamster ovary (CHO) cells are one of the most useful host cell lines for the production of biopharmaceutical proteins. Although a series of production processes have been refined to improve protein productivity and cost performance, establishing producer cells is still time-consuming and labor-intensive. Recombinase-mediated site-specific gene integration into a predetermined chromosomal locus may enable predictable protein expression, reducing the laborious process of cell screening. We previously developed an accumulative site-specific gene integration system (AGIS) using Cre recombinase and mutated loxP sites for transgene integration and amplification in the CHO cell genome. Epigenetic modifier elements such as insulators are effective DNA cis-regulatory elements for stabilizing transgene expression. Here, we attempted to enhance transgene expression in recombinant CHO cells generated by AGIS using a production enhancer DNA element (PE) derived from the CHO genome. The PE was introduced into an expression unit for a recombinant scFv-Fc antibody. The effect on scFv-Fc productivity of PE position and orientation within the transgene was evaluated, while keeping the background chromosomal structure constant. For the optimal PE arrangement, scFv-Fc productivity was enhanced 2.6-fold compared with an expression unit without a PE. The enhancing effect of the PE on transgene expression was also observed when two or three PE-flanked expression units were inserted as tandem repeats. These results indicate that AGIS using the PE-flanked expression unit is a promising approach for establishing producer cell lines for biopharmaceutical protein production.

  8. Chromosomal abnormalities in a psychiatric population

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, K.E.; Lubetsky, M.J.; Wenger, S.L.; Steele, M.W. [Univ. of Pittsburgh Medical Center, PA (United States)

    1995-02-27

    Over a 3.5 year period of time, 345 patients hospitalized for psychiatric problems were evaluated cytogenetically. The patient population included 76% males and 94% children with a mean age of 12 years. The criteria for testing was an undiagnosed etiology for mental retardation and/or autism. Cytogenetic studies identified 11, or 3%, with abnormal karyotypes, including 4 fragile X positive individuals (2 males, 2 females), and 8 with chromosomal aneuploidy, rearrangements, or deletions. While individuals with chromosomal abnormalities do not demonstrate specific behavioral, psychiatric, or developmental problems relative to other psychiatric patients, our results demonstrate the need for an increased awareness to order chromosomal analysis and fragile X testing in those individuals who have combinations of behavioral/psychiatric, learning, communication, or cognitive disturbance. 5 refs., 1 fig., 2 tabs.

  9. Positron Emission Tomography (PET Quantification of GABAA Receptors in the Brain of Fragile X Patients.

    Directory of Open Access Journals (Sweden)

    Charlotte D'Hulst

    Full Text Available Over the last several years, evidence has accumulated that the GABAA receptor is compromised in animal models for fragile X syndrome (FXS, a common hereditary form of intellectual disability. In mouse and fly models, agonists of the GABAA receptor were able to rescue specific consequences of the fragile X mutation. Here, we imaged and quantified GABAA receptors in vivo in brain of fragile X patients using Positron Emission Topography (PET and [11C]flumazenil, a known high-affinity and specific ligand for the benzodiazepine site of GABAA receptors. We measured regional GABAA receptor availability in 10 fragile X patients and 10 control subjects. We found a significant reduction of on average 10% in GABAA receptor binding potential throughout the brain in fragile X patients. In the thalamus, the brain region showing the largest difference, the GABAA receptor availability was even reduced with 17%. This is one of the first reports of a PET study of human fragile X brain and directly demonstrates that the GABAA receptor availability is reduced in fragile X patients. The study reinforces previous hypotheses that the GABAA receptor is a potential target for rational pharmacological treatment of fragile X syndrome.

  10. Common chromosomal imbalances and stemness-related protein expression markers in endometriotic lesions from different anatomical sites

    DEFF Research Database (Denmark)

    Silveira, Cássia G T; Abrão, Mauricio S; Dias, João A

    2012-01-01

    BACKGROUND: Endometriosis is a multifactorial gynecological disease characterized by the presence of functional endometrium-like tissue in ectopic sites. Several studies have focused on elucidating the immunological, endocrine, environmental and genetic factors involved in endometriosis. However...... genomic alterations in stromal and epithelial cells from different anatomical sites of the same patient and the expression of stemness-related markers suggested that endometriosis arises as a clonal proliferation with the putative involvement of stem cells....

  11. Ectodermal Dysplasia Skin Fragility Syndrome

    Directory of Open Access Journals (Sweden)

    Ayça Alan Atalay

    2014-06-01

    Full Text Available Ectodermal dysplasia-skin fragility syndrome (EDSFS is a rare autosomal recessive genodermatosis first described in 1997 by Mc Grath. EDSFS results from loss of function mutations in plakophilin-1 (PKP1. PKP1 is a structural component of desmosomes, cellcell adhesion complexes. It is also found as a nuclear protein in several cell types that are lack of desmosomes. In skin, however, PKP1 expression is confined mainly to suprabasal keratinocytes and the outer root sheath of hair follicules. Loss of function mutation in PKP1 leads to extensive skin fragility, bullae and erosions following minor trauma, focal keratoderma with painful fissures, alopecia, and nail dystrophy. In some patients hypohidrosis may also be seen. EDSFS is now considered as a specific suprabasal form of epidermolysis bullosa simplex. In this report we describe a 20 year old EDSFS case.

  12. Preserved entropy and fragile magnetism.

    Science.gov (United States)

    Canfield, Paul C; Bud'ko, Sergey L

    2016-08-01

    A large swath of quantum critical and strongly correlated electron systems can be associated with the phenomena of preserved entropy and fragile magnetism. In this overview we present our thoughts and plans for the discovery and development of lanthanide and transition metal based, strongly correlated systems that are revealed by suppressed, fragile magnetism, quantum criticality, or grow out of preserved entropy. We will present and discuss current examples such as YbBiPt, YbAgGe, YbFe2Zn20, PrAg2In, BaFe2As2, CaFe2As2, LaCrSb3 and LaCrGe3 as part of our motivation and to provide illustrative examples.

  13. Methylation of HpaII and HhaI sites near the polymorphic CAG repeat in the human androgen-receptor gene correlates with X chromosome inactivation

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.C.; Zoghbi, H.Y.; Moseley, A.B.; Rosenblatt, H.M.; Belmont, J.W. (Baylor College of Medicine, Houston (United States))

    1992-12-01

    The human androgen-receptor gene (HUMARA; GenBank) contains a highly polymorphic trinucleotide repeat in the first exon. The authors have found that the methylation of HpaII and HhaI sites less than 100 pb away from this polymorphic short tandem repeat (STR) correlates with X inactivation. The close proximity of the restriction-enzyme sites to the STR allows the development of a PCR assay that distinguishes between the maternal and paternal alleles and identifies their methylation status. The accuracy of this assay was tested on (a) DNA from hamster/human hybrid cell lines containing either an active or inactive human X chromosome; (b) DNA from normal males and females; and (c) DNA from females showing nonrandom patterns of X inactivation. Data obtained using this assay correlated substantially with those obtained using the PGK, HPRT, and M27[beta] probes, which detect X inactivation patterns by Southern blot analysis. In order to demonstrate one application of this assay, the authors examined X inactivation patterns in the B lymphocytes of potential and obligate carriers of X-linked agammaglobulinemia. 42 refs., 5 figs., 1 tab.

  14. Fragile Watermarking Based on Robust Hidden Information

    Institute of Scientific and Technical Information of China (English)

    张新鹏; 王朔中

    2003-01-01

    Block-wise fragile watermarks can be used to reveal maliciously tampered areas in multimedia products. However a forged content containing a cloned fragile watermark can be constructed by using a series of watermarked data. To defeat this type of counter-feit attack, a novel fragile watermarking technique is proposed in which different pseudo-random data are selected for different host products, and the generated fragile watermark is dependent upon the selected information. While inserting the fragile watermark, the pseudo-random information is also robustly embedded into the host data. Because of the difference between the selected information,different watermarked data cannot be used to forge illegal contents containing a valid fragile watermark.

  15. A Scandinavian case of skin fragility, alopecia and cardiomyopathy caused by DSP mutations.

    Science.gov (United States)

    Vahlquist, A; Virtanen, M; Hellström-Pigg, M; Dragomir, A; Ryberg, K; Wilson, N J; Östman--Smith, I; Lu, L; McGrath, J A; Smith, F J D

    2014-01-01

    Congenital skin fragility is a heterogeneous disorder with epidermolysis bullosa and various skin infections as the leading causes. However, even rare diseases must be considered in the differential diagnosis of neonatal skin blistering, including some genetic syndromes with extracutaneous involvement. One such syndrome is ectodermal dysplasia due to deficiency of desmoplakin, a desmosomal protein essential for cellular cohesion in both epithelia and cardiac tissues. Desmoplakin is encoded by the DSP gene, which is localized on chromosome 6p24. Both dominant and recessive mutations in this gene have been reported to cause skin fragility and keratinization defects. We report a child born with a fragile epidermis, alopecia, thick nails, and focal hyperkeratoses on the digits and knees. She was found to have a deficiency of desmoplakin caused by compound heterozygous DSP mutations. She has gradually developed signs of a left ventricular cardiomyopathy.

  16. Sequential cloning of chromosomes

    Science.gov (United States)

    Lacks, S.A.

    1995-07-18

    A method for sequential cloning of chromosomal DNA of a target organism is disclosed. A first DNA segment homologous to the chromosomal DNA to be sequentially cloned is isolated. The first segment has a first restriction enzyme site on either side. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction (class IIS) enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes. 9 figs.

  17. A PCR-free cloning method for the targeted φ80 Int-mediated integration of any long DNA fragment, bracketed with meganuclease recognition sites, into the Escherichia coli chromosome.

    Science.gov (United States)

    Ublinskaya, Anna A; Samsonov, Valeriy V; Mashko, Sergey V; Stoynova, Nataliya V

    2012-06-01

    The genetic manipulation of cells is the most promising strategy for designing microorganisms with desired traits. The most widely used approaches for integrating specific DNA-fragments into the Escherichia coli genome are based on bacteriophage site-specific and Red/ET-mediated homologous recombination systems. Specifically, the recently developed Dual In/Out integration strategy enables the integration of DNA fragments directly into specific chromosomal loci (Minaeva et al., 2008). To develop this strategy further, we designed a method for the precise cloning of any long DNA fragments from the E. coli chromosome and their targeted insertion into the genome that does not require PCR. In this method, the region of interest is flanked by I-SceI rare-cutting restriction sites, and the I-SceI-bracketed region is cloned into the unique I-SceI site of an integrative plasmid vector that then enables its targeted insertion into the E. coli chromosome via bacteriophage φ80 Int-mediated specialized recombination. This approach allows any long specific DNA fragment from the E. coli genome to be cloned without a PCR amplification step and reproducibly inserted into any chosen chromosomal locus. The developed method could be particularly useful for the construction of marker-less and plasmid-less recombinant strains in the biotechnology industry.

  18. 53BP1 nuclear bodies form around DNA lesions generated by mitotic transmission of chromosomes under replication stress

    DEFF Research Database (Denmark)

    Lukas, Claudia; Savic, Velibor; Bekker-Jensen, Simon;

    2011-01-01

    Completion of genome duplication is challenged by structural and topological barriers that impede progression of replication forks. Although this can seriously undermine genome integrity, the fate of DNA with unresolved replication intermediates is not known. Here, we show that mild replication...... bodies shield chromosomal fragile sites sequestered in these compartments against erosion. Together, these data indicate that restoration of DNA or chromatin integrity at loci prone to replication problems requires mitotic transmission to the next cell generations....... increases after genetic ablation of BLM, a DNA helicase associated with dissolution of entangled DNA. Conversely, 53BP1 nuclear bodies are partially suppressed by knocking down SMC2, a condensin subunit required for mechanical stability of mitotic chromosomes. Finally, we provide evidence that 53BP1 nuclear...

  19. Seismic fragility of nuclear power plant components (Phase 2): A fragility handbook on eighteen components

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, K.K.; Hofmayer, C.H.; Kassir, M.K.; Shteyngart, S. (Brookhaven National Lab., Upton, NY (United States))

    1991-06-01

    Fragility estimates of seven equipment classes were published in earlier reports. This report presents fragility analysis results from eleven additional equipment categories. The fragility levels are expressed in probabilistic terms. For users' convenience, this concluding report includes a summary of fragility results of all eighteen equipment classes. A set of conversion factors based on judgment is recommended for use of the information for early vintage equipment. The knowledge gained in conducting the Component Fragility Program and similar other programs is expected to provide a new direction for seismic verification and qualification of equipment. 15 refs., 12 tabs.

  20. A novel system for simultaneous or sequential integration of multiple gene-loading vectors into a defined site of a human artificial chromosome.

    Directory of Open Access Journals (Sweden)

    Teruhiko Suzuki

    Full Text Available Human artificial chromosomes (HACs are gene-delivery vectors suitable for introducing large DNA fragments into mammalian cells. Although a HAC theoretically incorporates multiple gene expression cassettes of unlimited DNA size, its application has been limited because the conventional gene-loading system accepts only one gene-loading vector (GLV into a HAC. We report a novel method for the simultaneous or sequential integration of multiple GLVs into a HAC vector (designated as the SIM system via combined usage of Cre, FLP, Bxb1, and φC31 recombinase/integrase. As a proof of principle, we first attempted simultaneous integration of three GLVs encoding EGFP, Venus, and TdTomato into a gene-loading site of a HAC in CHO cells. These cells successfully expressed all three fluorescent proteins. Furthermore, microcell-mediated transfer of HACs enabled the expression of those fluorescent proteins in recipient cells. We next demonstrated that GLVs could be introduced into a HAC one-by-one via reciprocal usage of recombinase/integrase. Lastly, we introduced a fourth GLV into a HAC after simultaneous integration of three GLVs by FLP-mediated DNA recombination. The SIM system expands the applicability of HAC vectors and is useful for various biomedical studies, including cell reprogramming.

  1. A novel system for simultaneous or sequential integration of multiple gene-loading vectors into a defined site of a human artificial chromosome.

    Science.gov (United States)

    Suzuki, Teruhiko; Kazuki, Yasuhiro; Oshimura, Mitsuo; Hara, Takahiko

    2014-01-01

    Human artificial chromosomes (HACs) are gene-delivery vectors suitable for introducing large DNA fragments into mammalian cells. Although a HAC theoretically incorporates multiple gene expression cassettes of unlimited DNA size, its application has been limited because the conventional gene-loading system accepts only one gene-loading vector (GLV) into a HAC. We report a novel method for the simultaneous or sequential integration of multiple GLVs into a HAC vector (designated as the SIM system) via combined usage of Cre, FLP, Bxb1, and φC31 recombinase/integrase. As a proof of principle, we first attempted simultaneous integration of three GLVs encoding EGFP, Venus, and TdTomato into a gene-loading site of a HAC in CHO cells. These cells successfully expressed all three fluorescent proteins. Furthermore, microcell-mediated transfer of HACs enabled the expression of those fluorescent proteins in recipient cells. We next demonstrated that GLVs could be introduced into a HAC one-by-one via reciprocal usage of recombinase/integrase. Lastly, we introduced a fourth GLV into a HAC after simultaneous integration of three GLVs by FLP-mediated DNA recombination. The SIM system expands the applicability of HAC vectors and is useful for various biomedical studies, including cell reprogramming.

  2. Isolation of Ty1-copia-like Retrotransposon Sequences from the Apple Genome by Chromosome Walking Based on Modified SiteFinding-polymerase Chain Reaction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Long terminal repeat (LTR) retrotransposons are powerful tools for studying genetic biodiversity,genome evolution, gene mutation, gene cloning and gene expression. The scarcity of retrotransposon sequence information restricts the development of these studies in higher plants. In the present study, 31 reverse transcriptase (RT) genes of Tyl-copia-like retrotransposons were identified from the apple genome by amplifying the RT coding region using degenerate primers. Nineteen RT genes showed extreme heterogeneity in terms of fragment size, base pair composition and open reading frame integrality. Originating from one 266 bp cloned RT gene, a 1966 bp Ty1-copia-like retrotransposon (named Tcrm1), including RT-ribonuclease H-LTR domain sequences, was achieved by chromosome walking based on modified SiteFinding-polymerase chain reaction. The comparison between Tcrm1 and other LTR retrotransposons in gene structure and sequence homology shows that Tcrm1 is the first Ty1-copia-like retrotransposon including an LTR domain in the apple genome. Dot blot analysis revealed that Tcrm1 copy number in the apple was approximately 1×103 copies per haploid genome.

  3. Phage 8-9 defines a cluster of site polymorphisms on chromosome 16q22-q24 (HGM9 no. D16S20)

    Energy Technology Data Exchange (ETDEWEB)

    Maslen, C.; Magenis, R.E.; Sheehy, R.; Litt, M. (Oregon Health Sciences Univ., Portland (USA))

    1988-08-25

    Phage 8-9 was isolated from a genomic library of a mouse x human somatic cell hybrid (CF-52) containing an 11q-16q translocation as the only human chromosome. A 17 kb partial Sau 3A fragment was cloned in the BamHI site of EMBL3. Sac I identifies constant bands at 4.1, 2.3 and 1.3 kb and two 2-allele RFLPs with A1=10, A2=7.4+2.6 kb and B1=2.9, B2=1.9+1.0 kb. BgI II identifies a constant band of 8 kb and a 3-allele RFLP. Pvu II identifies 8 constant bands <3.5 kb and a 2-allele RFLP with D1=6.5, D2=5.8+0.7 kb. Co-dominant inheritance has been shown at each of the four loci in at least 2 informative families with a total of at least 13 children.

  4. Financial fragility in the Great Moderation

    NARCIS (Netherlands)

    Bezemer, Dirk; Grydaki, Maria

    2014-01-01

    A nascent literature explores the measurement of financial fragility. This paper considers evidence for rising financial fragility during the 1984-2007 Great Moderation in the U.S. The literature suggests that macroeconomic stability combined with strong growth of credit to asset markets, in asset p

  5. 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…

  6. Cytogenetic abnormalities and fragile-x syndrome in Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Reddy Kavita S

    2005-01-01

    Full Text Available Abstract Background Autism is a behavioral disorder with impaired social interaction, communication, and repetitive and stereotypic behaviors. About 5–10 % of individuals with autism have 'secondary' autism in which an environmental agent, chromosome abnormality, or single gene disorder can be identified. Ninety percent have idiopathic autism and a major gene has not yet been identified. We have assessed the incidence of chromosome abnormalities and Fragile X syndrome in a population of autistic patients referred to our laboratory. Methods Data was analyzed from 433 patients with autistic traits tested using chromosome analysis and/or fluorescence in situ hybridization (FISH and/or molecular testing for fragile X syndrome by Southern and PCR methods. Results The median age was 4 years. Sex ratio was 4.5 males to 1 female [354:79]. A chromosome (cs abnormality was found in 14/421 [3.33 %] cases. The aberrations were: 4/14 [28%] supernumerary markers; 4/14 [28%] deletions; 1/14 [7%] duplication; 3/14 [21%] inversions; 2/14 [14%] translocations. FISH was performed on 23 cases for reasons other than to characterize a previously identified cytogenetic abnormality. All 23 cases were negative. Fragile-X testing by Southern blots and PCR analysis found 7/316 [2.2 %] with an abnormal result. The mutations detected were: a full mutation (fM and abnormal methylation in 3 [43 %], mosaic mutations with partial methylation of variable clinical significance in 3 [43%] and a permutation carrier [14%]. The frequency of chromosome and fragile-X abnormalities appears to be within the range in reported surveys (cs 4.8-1.7%, FRAX 2–4%. Limitations of our retrospective study include paucity of behavioral diagnostic information, and a specific clinical criterion for testing. Conclusions Twenty-eight percent of chromosome abnormalities detected in our study were subtle; therefore a high resolution cytogenetic study with a scrutiny of 15q11.2q13, 2q37 and Xp23

  7. Fragile X syndrome: Current insight

    Directory of Open Access Journals (Sweden)

    Deepika Delsa Dean

    2016-10-01

    Full Text Available Fragile X syndrome (FXS is a multigenerational disorder having massive adverse effect not only on the individuals but also on their families. It is the most common type of intellectual disability after Down’s syndrome. Over two decades have passed since the discovery of FMR1, the causal gene for FXS, but still little is known about the pathophysiology of this disease. This lack of knowledge presents the major barrier encountered by the scientific community for early diagnosis and effective treatment. Since early diagnosis has important implication in determining the disease status among members of the family tree so the genetic counseling and supportive therapy get hampered in larger perspective. The present review emphasizes on the recent findings in FXS pathophysiology, therapeutics and technical challenges in molecular diagnosis.

  8. Spp1, a member of the Set1 Complex, promotes meiotic DSB formation in promoters by tethering histone H3K4 methylation sites to chromosome axes.

    Science.gov (United States)

    Sommermeyer, Vérane; Béneut, Claire; Chaplais, Emmanuel; Serrentino, Maria Elisabetta; Borde, Valérie

    2013-01-10

    Meiotic chromosomes are organized into arrays of loops that are anchored to the chromosome axis structure. Programmed DNA double-strand breaks (DSBs) that initiate meiotic recombination, catalyzed by Spo11 and accessory DSB proteins, form in loop sequences in promoters, whereas the DSB proteins are located on chromosome axes. Mechanisms bridging these two chromosomal regions for DSB formation have remained elusive. Here we show that Spp1, a conserved member of the histone H3K4 methyltransferase Set1 complex, is required for normal levels of DSB formation and is associated with chromosome axes during meiosis, where it physically interacts with the Mer2 DSB protein. The PHD finger module of Spp1, which reads H3K4 methylation close to promoters, promotes DSB formation by tethering these regions to chromosome axes and activating cleavage by the DSB proteins. This paper provides the molecular mechanism linking DSB sequences to chromosome axes and explains why H3K4 methylation is important for meiotic recombination.

  9. Molecular/clinical correlations in females with fragile X

    Energy Technology Data Exchange (ETDEWEB)

    Sobesky, W.E.; Riddle, J.; Hagerman, R.J. [Children`s Hospital, Denver, CO (United States)] [and others

    1996-08-09

    Females who are affected by fragile X syndrome (FXS) can have significant physical, neuropsychological and emotional involvement. This study was designed to explore the relationships between these three domains and to learn how the degree of involvement in each of these phenotypic areas relates to molecular parameters including CGG repeat length and activation ratio (the proportion of normal FMR1 alleles on the active X chromosome). Three groups of females were studied: 35 women who grew up in a fragile X family but do not carry an FMR1 mutation, 92 women with a premutation, and 29 women with a full mutation. Correlations between neurocognitive, physical and emotional traits were calculated for each of the three groups. Within the full mutation group significant correlations were seen between schizotypal traits and full scale IQ. The Lie scale was significantly correlated with the physical findings index. The activation ratio correlated significantly with the measure of executive function (r = .50, P = .01). There was a trend toward correlations of activation ratio with the physical index score, outer ear prominence and IQ. CGG repeat number significantly correlated only with the physical index (r = .44, P = .0 1). Thus, activation ratio may be the more pertinent molecular parameter in full mutation women in determining the degree of cognitive and physical phenotypic involvement. 29 refs., 2 tabs.

  10. Event-related potential alterations in fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Inga Sophia eKnoth

    2012-09-01

    Full Text Available Fragile X Syndrome (FXS is the most common form of X-linked intellectual disability, associated with a wide range of cognitive and behavioural impairments. FXS is caused by a trinucleotide repeat expansion in the FMR1 gene located on the X-chromosome. FMR1 is expected to prevent the expression of the fragile X mental retardation protein (FMRP, which results in altered structural and functional development of the synapse, including a loss of synaptic plasticity. This review aims to unveil the contribution of electrophysiological signal studies for the understanding of the information processing impairments in FXS patients. We discuss relevant event-related potential (ERP studies conducted with full mutation FXS patients and clinical populations sharing symptoms with FXS in a developmental perspective. Specific deviances found in FXS ERP profiles are described. Alterations are reported in N1, P2, Mismatch Negativity (MMN, N2 and P3 components in FXS compared to healthy controls. Particularly, deviances in N1 and P2 amplitude seem to be specific to FXS. The presented results suggest a cascade of impaired information processes that are in line with symptoms and anatomical findings in FXS.

  11. Modeling fragile X syndrome in the Fmr1 knockout mouse.

    Science.gov (United States)

    Kazdoba, Tatiana M; Leach, Prescott T; Silverman, Jill L; Crawley, Jacqueline N

    2014-11-01

    Fragile X Syndrome (FXS) is a commonly inherited form of intellectual disability and one of the leading genetic causes for autism spectrum disorder. Clinical symptoms of FXS can include impaired cognition, anxiety, hyperactivity, social phobia, and repetitive behaviors. FXS is caused by a CGG repeat mutation which expands a region on the X chromosome containing the FMR1 gene. In FXS, a full mutation (> 200 repeats) leads to hypermethylation of FMR1, an epigenetic mechanism that effectively silences FMR1 gene expression and reduces levels of the FMR1 gene product, fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein that is important for the regulation of protein expression. In an effort to further understand how loss of FMR1 and FMRP contribute to FXS symptomology, several FXS animal models have been created. The most well characterized rodent model is the Fmr1 knockout (KO) mouse, which lacks FMRP protein due to a disruption in its Fmr1 gene. Here, we review the behavioral phenotyping of the Fmr1 KO mouse to date, and discuss the clinical relevance of this mouse model to the human FXS condition. While much remains to be learned about FXS, the Fmr1 KO mouse is a valuable tool for understanding the repercussions of functional loss of FMRP and assessing the efficacy of pharmacological compounds in ameliorating the molecular and behavioral phenotypes relevant to FXS.

  12. Event-related potential alterations in fragile X syndrome.

    Science.gov (United States)

    Knoth, Inga S; Lippé, Sarah

    2012-01-01

    Fragile X Syndrome (FXS) is the most common form of X-linked intellectual disability (ID), associated with a wide range of cognitive and behavioral impairments. FXS is caused by a trinucleotide repeat expansion in the FMR1 gene located on the X-chromosome. FMR1 is expected to prevent the expression of the "fragile X mental retardation protein (FMRP)", which results in altered structural and functional development of the synapse, including a loss of synaptic plasticity. This review aims to unveil the contribution of electrophysiological signal studies for the understanding of the information processing impairments in FXS patients. We discuss relevant event-related potential (ERP) studies conducted with full mutation FXS patients and clinical populations sharing symptoms with FXS in a developmental perspective. Specific deviances found in FXS ERP profiles are described. Alterations are reported in N1, P2, Mismatch Negativity (MMN), N2, and P3 components in FXS compared to healthy controls. Particularly, deviances in N1 and P2 amplitude seem to be specific to FXS. The presented results suggest a cascade of impaired information processes that are in line with symptoms and anatomical findings in FXS.

  13. Evidence that methylation of the FMR-I locus is responsible for variable phenotypic expression of the fragile X syndrome

    Energy Technology Data Exchange (ETDEWEB)

    McConkie-Rosell, A.; Lachiewicz, A.M.; Spiridigliozzi, G.A.; Shoenwald, S. (Duke Univ., Durham, NC (United States)); Tarleton, J.; Phelan, M.C. (Greenwood Genetics Center, Greenwood, SC (United States)); Goonewardena, P. (Kaiser Permanente, San Jose, CA (United States)); Ding, X.; Brown, W.T. (Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States))

    1993-10-01

    DNA at the FMR-1 locus was analyzed by Southern blot using probe StB12.3 in an unusual fragile X family with six brothers, three of whom are affected with fragile X to varying degrees, two of whom are nonpenetrant carriers, and one of whom is unaffected. Fragile X chromosome studies, detailed physical examinations, and psychological testing were completed on all six. Two of the affected brothers and the two nonpenetrant brothers were found to be methylation mosaics. The three affected males spanned the phenotypic and cognitive spectrum of the fragile X syndrome. A correlation was seen between the degree of methylation and the phenotypic expression identified in the three affected males. The two males initially classified as nonpenetrant were found to have mild phenotypic expression which consisted of minor cognitive deficits and a partial physical phenotype. These two, who were negative on fragile X chromosome studies, were found on DNA analysis to have large broad smears, with approximately 97% of the DNA unmethylated. The results described here indicate that some [open quotes]nonpenetrant[close quotes] carrier males may have varying amounts of methylation of the FMR-1 region, which can result in mild expression of the fragile X syndrome. The apparently mild phenotypic and cognitive expression of the fragile X syndrome in the two males, initially classified as nonpenetrant, who are mosaic for hypermethylation of an expansion of the CGG repeat in the premutation range, indicates that expression of the syndrome is not confined to males with large, hypermethylated expansions (full mutation) but has instead a gradient effect with a threshold for the full expression of the phenotype. 41 refs., 2 tabs.

  14. Fork rotation and DNA precatenation are restricted during DNA replication to prevent chromosomal instability.

    Science.gov (United States)

    Schalbetter, Stephanie A; Mansoubi, Sahar; Chambers, Anna L; Downs, Jessica A; Baxter, Jonathan

    2015-08-18

    Faithful genome duplication and inheritance require the complete resolution of all intertwines within the parental DNA duplex. This is achieved by topoisomerase action ahead of the replication fork or by fork rotation and subsequent resolution of the DNA precatenation formed. Although fork rotation predominates at replication termination, in vitro studies have suggested that it also occurs frequently during elongation. However, the factors that influence fork rotation and how rotation and precatenation may influence other replication-associated processes are unknown. Here we analyze the causes and consequences of fork rotation in budding yeast. We find that fork rotation and precatenation preferentially occur in contexts that inhibit topoisomerase action ahead of the fork, including stable protein-DNA fragile sites and termination. However, generally, fork rotation and precatenation are actively inhibited by Timeless/Tof1 and Tipin/Csm3. In the absence of Tof1/Timeless, excessive fork rotation and precatenation cause extensive DNA damage following DNA replication. With Tof1, damage related to precatenation is focused on the fragile protein-DNA sites where fork rotation is induced. We conclude that although fork rotation and precatenation facilitate unwinding in hard-to-replicate contexts, they intrinsically disrupt normal chromosome duplication and are therefore restricted by Timeless/Tipin.

  15. Caregiver Burden in Fragile X Families.

    Science.gov (United States)

    Iosif, Ana-Maria; Sciolla, Andres F; Brahmbhatt, Khyati; Seritan, Andreea L

    2013-02-01

    Complex caregiving issues occur in multigenerational families carrying the fragile X mutation and premutation. The same family members may care for children or siblings with fragile X syndrome (FXS) and for elderly parents with fragile X-associated tremor/ataxia syndrome (FXTAS). Family caregivers experience anxiety, depression, neglect of personal health care needs, employment difficulties, and loss of social support, leading to isolation and further psychiatric consequences. There is growing awareness of caregiver burden with regard to parents of children with FXS, but much less is known about the needs of informal caregivers of patients with FXTAS. In this paper, we review the available literature to date and provide suggestions for further exploration of caregivers' needs. Evidence-based strategies to address these needs are included. Many more research studies exploring caregiver burden in multigenerational fragile X families are needed, as well as studies aimed at investigating interventions and their impact on reduction.

  16. Germline mosaicism at the fragile X locus.

    Science.gov (United States)

    Prior, T W; Papp, A C; Snyder, P J; Sedra, M S; Guida, M; Enrile, B G

    1995-01-30

    We have identified a fragile X syndrome pedigree where the disorder is associated with a molecular deletion. The deletion was present in the DNA of 2 sons but was absent in the mother's somatic cell (lymphocyte) DNA. The results are consistent with the deletion arising as a postzygotic event in the mother, who therefore is germinally mosaic. This finding has important implications for counseling fragile X families with deletion mutations.

  17. Fragile phagocytes: FMRP positively regulates engulfment activity.

    Science.gov (United States)

    Logan, Mary A

    2017-03-06

    Defective immune system function is implicated in autism spectrum disorders, including Fragile X syndrome. In this issue, O'Connor et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607093) demonstrate that phagocytic activity of systemic immune cells is compromised in a Drosophila melanogaster model of Fragile X, highlighting intriguing new mechanistic connections between FMRP, innate immunity, and abnormal development.

  18. Analysis of unstable DNA sequence in FRM1 gene in Polish families with fragile X syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Milewski, Michal; Bal, Jerzy; Obersztyn, Ewa; Bocian, Ewa; Mazurczak, Tadeusz [Instytut Matki i Dziecka, Warsaw (Poland); Zygulska, Marta; Horst, Juergen [Institute of Human Genetics, Muenster (Germany); Deelen, Wout H.; Halley, Dicky J.J. [Erasmus Univ., Rotterdam (Netherlands)

    1996-12-31

    The unstable DNA sequence in the FMR1 gene was analyzed in 85 individuals from Polish families with fragile X syndrome in order to characterize mutations responsible for the disease in Poland. In all affected individuals classified on the basis of clinical features and expression of the fragile site at X(q27.3) a large expansion of the unstable sequence (full mutation) was detected. About 5% (2 of 43) of individuals with full mutation did not express the fragile site. Among normal alleles, ranging in size from 20 to 41 CGC repeats, allele with 29 repeats was the most frequent (37%). Transmission of premutated and fully mutated alleles to the offspring was always associated with size increase. No change in repeat number was found when normal alleles were transmitted. (author). 19 refs., 4 figs, 1 tab.

  19. Isolation and genetic charac-terization of a fragile plantmutant in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The fragile rice mutant was isolated from an M2 population of indica variety Shuang Ke Zao (SKZ) treated with (-rays, and designated as fp1 (fragile plant 1) because of its fragile leaves and culms. To map FP1 locus, an F2 mapping population was derived from a cross between the fp1 and C-bao, a polymorphic japonic variety. The primary mapping result places the FP1 locus in an interval between two molecular markers, microsatellite marker RM16 (3.1 cM proximal to FP1) and STS marker G144a (9.1 cM distal to FP1) in the centromere region of chromosome 3. A CAPS marker C524a was further developed between RM16 and G144a, with 0.4 cM genetic distances to the FP1 locus, providing a practical starting point for constructing a BAC contig spanning the FP1 locus and cloning the fp1 gene. Allelism test demonstrated that fp1 is allelic to bc1, a fragile rice mutant reported previously.

  20. Rad54 and Mus81 cooperation promotes DNA damage repair and restrains chromosome missegregation

    DEFF Research Database (Denmark)

    Ghamrasni, S El; Cardoso, R; Li, L;

    2016-01-01

    Rad54 and Mus81 mammalian proteins physically interact and are important for the homologous recombination DNA repair pathway; however, their functional interactions in vivo are poorly defined. Here, we show that combinatorial loss of Rad54 and Mus81 results in hypersensitivity to DNA......-damaging agents, defects on both the homologous recombination and non-homologous DNA end joining repair pathways and reduced fertility. We also observed that while Mus81 deficiency diminished the cleavage of common fragile sites, very strikingly, Rad54 loss impaired this cleavage to even a greater extent....... The inefficient repair of DNA double-strand breaks (DSBs) in Rad54(-/-)Mus81(-/-) cells was accompanied by elevated levels of chromosome missegregation and cell death. Perhaps as a consequence, tumor incidence in Rad54(-/-)Mus81(-/-) mice remained comparable to that in Mus81(-/-) mice. Our study highlights...

  1. Synthetic chromosomes.

    Science.gov (United States)

    Schindler, Daniel; Waldminghaus, Torsten

    2015-11-01

    What a living organism looks like and how it works and what are its components-all this is encoded on DNA, the genetic blueprint. Consequently, the way to change an organism is to change its genetic information. Since the first pieces of recombinant DNA have been used to transform cells in the 1970s, this approach has been enormously extended. Bigger and bigger parts of the genetic information have been exchanged or added over the years. Now we are at a point where the construction of entire chromosomes becomes a reachable goal and first examples appear. This development leads to fundamental new questions, for example, about what is possible and desirable to build or what construction rules one needs to follow when building synthetic chromosomes. Here we review the recent progress in the field, discuss current challenges and speculate on the appearance of future synthetic chromosomes.

  2. Comparative genomic mapping of the bovine Fragile Histidine Triad (FHIT tumour suppressor gene: characterization of a 2 Mb BAC contig covering the locus, complete annotation of the gene, analysis of cDNA and of physiological expression profiles

    Directory of Open Access Journals (Sweden)

    Boussaha Mekki

    2006-05-01

    Full Text Available Abstract Background The Fragile Histidine Triad gene (FHIT is an oncosuppressor implicated in many human cancers, including vesical tumors. FHIT is frequently hit by deletions caused by fragility at FRA3B, the most active of human common fragile sites, where FHIT lays. Vesical tumors affect also cattle, including animals grazing in the wild on bracken fern; compounds released by the fern are known to induce chromosome fragility and may trigger cancer with the interplay of latent Papilloma virus. Results The bovine FHIT was characterized by assembling a contig of 78 BACs. Sequence tags were designed on human exons and introns and used directly to select bovine BACs, or compared with sequence data in the bovine genome database or in the trace archive of the bovine genome sequencing project, and adapted before use. FHIT is split in ten exons like in man, with exons 5 to 9 coding for a 149 amino acids protein. VISTA global alignments between bovine genomic contigs retrieved from the bovine genome database and the human FHIT region were performed. Conservation was extremely high over a 2 Mb region spanning the whole FHIT locus, including the size of introns. Thus, the bovine FHIT covers about 1.6 Mb compared to 1.5 Mb in man. Expression was analyzed by RT-PCR and Northern blot, and was found to be ubiquitous. Four cDNA isoforms were isolated and sequenced, that originate from an alternative usage of three variants of exon 4, revealing a size very close to the major human FHIT cDNAs. Conclusion A comparative genomic approach allowed to assemble a contig of 78 BACs and to completely annotate a 1.6 Mb region spanning the bovine FHIT gene. The findings confirmed the very high level of conservation between human and bovine genomes and the importance of comparative mapping to speed the annotation process of the recently sequenced bovine genome. The detailed knowledge of the genomic FHIT region will allow to study the role of FHIT in bovine cancerogenesis

  3. mBAND Analysis of Early and Late Damages in the Chromosome of Human Lymphocytes after Exposures to Gamma Rays and Fe Ions

    Science.gov (United States)

    Sunagawa, Mayumi; Zhang, Ye; Yeshitla, Samrawit; Kadhim, Munira; Wilson, Bobby; Wu, Honglu

    2013-01-01

    Stable type chromosome aberrations that survive multiple generations of cell division include translocation and inversions. An efficient method to detect an inversion is multi-color banding fluorescent in situ hybridization (mBAND) which allows identification of both inter- and intrachromosome aberrations simultaneously. Post irradiation, chromosome aberrations may also arise after multiple cell divisions as a result of genomic instability. To investigate the stable or late-arising chromosome aberrations induced after radiation exposure, we exposed human lymphocytes to gamma rays and Fe ions ex vivo, and cultured the cells for multiple generations. Chromosome aberrations were analyzed in cells collected at first mitosis and at several time intervals during the culture period post irradiation. With gamma irradiation, about half of the damages observed at first mitosis remained after 7 day- and 14 day- culture, suggesting the transmissibility of damages to the surviving progeny. At the doses that produced similar frequencies of gamma-induced chromosome aberrations as observed at first mitosis, a significantly lower yield of aberrations remained at the same population doublings after Fe ion exposure. At these equitoxic doses, more complex type aberrations were observed for Fe ions, indicating that Fe ion-induced initial chromosome damages are more severe and may lead to cell death. Detailed analysis of breaks participating in total chromosome exchanges within the first cell cycle post irradiation revealed a common hotspot located in the 3p21 region, which is a known fragile site corresponding to the band 6 in the mBand analysis. The breakpoint distribution in chromosomes collected at 7 days, but not at 14 days, post irradiation appeared similar to the distribution in cells collected within the first cell cycle post irradiation. The breakpoint distribution for human lymphocytes after radiation exposure was different from the previously published distribution for human

  4. Psychometric Study of the Aberrant Behavior Checklist in Fragile X Syndrome and Implications for Targeted Treatment

    Science.gov (United States)

    Sansone, Stephanie M.; Widaman, Keith F.; Hall, Scott S.; Reiss, Allan L.; Lightbody, Amy; Kaufmann, Walter E.; Berry-Kravis, Elizabeth; Lachiewicz, Ave; Brown, Elaine C.; Hessl, David

    2012-01-01

    Animal studies elucidating the neurobiology of fragile X syndrome (FXS) have led to multiple controlled trials in humans, with the Aberrant Behavior Checklist-Community (ABC-C) commonly adopted as a primary outcome measure. A multi-site collaboration examined the psychometric properties of the ABC-C in 630 individuals (ages 3-25) with FXS using…

  5. Local development in fragile areas

    Directory of Open Access Journals (Sweden)

    Francesca Governa

    2009-03-01

    Full Text Available During the last 20 years some keywords have been extensively used in international debate about local development policies: bottom-up approach, territoriality, policy integration, partnership, cooperation and negotiation among actors and interests. The use of these keywords hides a variety of cultural approaches, theories and practices; this means that we should study local development processes and policies analysing and deconstructing these theoretical approaches in specific situations and experiences. Within this framework, the article critically discuss local development policies involving “fragile” areas like those of the mountains in Lombardy. Reference will be made mainly to the results of a research-action activity on the integrated local development programmes (PISL for the Objective 2 areas of the Region financed during the period of European structural funds programming 2000-2006.Durant les vingt dernières années, quelques mots-clés ont été intensivement employés dans le débat international sur les politiques de développement local : bottom-up approach, territorialité, intégration politique, association, coopération et négociation entre les acteurs et les intérêts. L’utilisation de ce vocabulaire cache une série d’approches, théories et pratiques culturelles. Pour ne pas seulement se contenter de mots, il est nécessaire d’étudier les processus de développement et les politiques locales en analysant et déconstruisant les différentes approches théoriques à la lumière de situations et d’expériences spécifiques. Pour ce faire, cet article présente les politiques de développement local dans des zones fragiles telles que les montagnes de Lombardie. On fera principalement référence aux résultats d’une recherche-action sur les programmes de développement locaux intégrés (PISL pour les territoires de l’Objectif 2 de cette région, programmes financés au cours de la période 2000-2006 par des

  6. An atypical case of fragile X syndrome caused by a deletion that includes FMRI gene

    Energy Technology Data Exchange (ETDEWEB)

    Quan, F.; Zonana, J.; Gunter, K.; Peterson, K.L.; Magenis, R.E., Popovich, B.W. [Shriners Hospital for Crippled Children, Portland, OR (United States)

    1995-05-01

    Fragile X syndrome is the most common form of inherited mental retardation and results from the transcriptional inactivation of the FMR1 gene. In the vast majority of cases, this is caused by the expansion of an unstable CGG repeat in the first exon of the FMR1 gene. We describe here a phenotypically atypical case of fragile X syndrome, caused by a deletion that includes the entire FMR1 gene and {ge}9.0 Mb of flanking DNA. The proband, RK, was a 6-year-old mentally retarded male with obesity and anal atresia. A diagnosis of fragile X syndrome was established by the failure of RK`s DNA to hybridize to a 558-bp PstI-XhoI fragment (pfxa3) specific for the 5{prime}-end of the FMR1 gene. The analysis of flanking markers in the interval from Xq26.3-q28 indicated a deletion extending from between 160-500 kb distal and 9.0 Mb proximal to the FMR1 gene. High-resolution chromosome banding confirmed a deletion with breakpoints in Xq26.3 and Xq27.3. This deletion was maternally transmitted and arose as a new mutation on the grandpaternal X chromosome. The maternal transmission of the deletion was confirmed by FISH using a 34-kb cosmid (c31.4) containing most of the FMR1 gene. These results indicated that RK carried a deletion of the FMR1 region with the most proximal breakpoint described to date. This patient`s unusual clinical presentation may indicate the presence of genes located in the deleted interval proximal to the FMR1 locus that are able to modify the fragile X syndrome phenotype. 36 refs., 7 figs.

  7. [The many facets of inherited skin fragility].

    Science.gov (United States)

    Has, C; Kiritsi, D

    2014-06-01

    The inherited skin fragility encompasses a heterogeneous group of disorders, collectively designated as epidermolysis bullosa, characterized by recurrent mechanically induced blisters, erosions or wounds. The spectrum of clinical manifestations is broad, as well as the molecular background. Besides the skin, mucosal membranes and other organs can be affected. In real-world practice, patients with mild genetic skin fragility usually do not require medical care and often remain underdiagnosed. In contrast, the well-defined severe EB subtypes are recognized based on typical clinical features. The molecular diagnostics is usually performed in order to allow genetic counselling and prenatal diagnosis. Besides wound care and careful management of the disease complications, new experimental targeted therapies are being developed. New very rare forms of inherited skin fragility have been identified with modern sequencing methods.

  8. Practical Approach to Fragility Analysis of Bridges

    Directory of Open Access Journals (Sweden)

    Yasamin Rafie Nazari

    2012-12-01

    Full Text Available Damages during past earthquakes reveal seismic vulnerability of bridge structures and the necessity of probabilistic approach toward seismic performance evaluation of bridges and its interpretation in terms of decision variables such as repair cost, downtime and life loss. This Procedure involves hazard analysis, structural analysis, damage analysis and loss analysis. The purpose of present study is reviewing different methods developed to derive fragility curves for damage analysis of bridges and demonstrating a simple procedure for fragility analysis using Microsoft Office Excel worksheet to reach probability of occurring predefined level of damage due to different levels of seismic demand parameters. The input of this procedure is the intensity of ground motion and the output is an appropriate estimate of the expected damage. Different observed damages of the bridges are discussed and compared the practical definition of damage states. Different methods of fragility analyses are discussed and a practical step by step example is illustrated.

  9. Genetic diagnosis in clinical psychiatry: A case report of a woman with a 47, XXX karyotype and Fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Anthony M. Vandersteen

    2009-03-01

    Full Text Available Background and Objectives: A recent report highlighted the importance of considering a chromosomal abnormality in the differential diagnosis of adult clinical psychiatry. This case report illustrates the importance of considering Fragile X syndrome, an X-linked genetic disorder associated with psychiatric morbidities. Methods: A 45 years old woman was referred to the clinical genetics department by her psychiatrist for investigation of her gross obesity, hyperphagia, learning difficulties and affective disorder. Results: Cytogenetic analysis revealed a 47,XXX karyotype. Molecular testing identified an expansion of approximately 580 repeats in the FRAXA gene carried on two of her three copies of the X chromosome. Clinical evaluation revealed features consistent with the Prader-Willi like phenotype of Fragile X syndrome. Conclusions: It is important to consider molecular and cytogenetic testing in patients with dysmorphic features, complex neuro-behavioural profile and/or psychotic disorders in order to establish a causative diagnosis, provide adequate counselling and initiate cascade screening where applicable.

  10. Chromosome-specific segmentation revealed by structural analysis of individually isolated chromosomes.

    Science.gov (United States)

    Kitada, Kunio; Taima, Akira; Ogasawara, Kiyomoto; Metsugi, Shouichi; Aikawa, Satoko

    2011-04-01

    Analysis of structural rearrangements at the individual chromosomal level is still technologically challenging. Here we optimized a chromosome isolation method using fluorescent marker-assisted laser-capture and laser-beam microdissection and applied it to structural analysis of two aberrant chromosomes found in a lung cancer cell line. A high-density array-comparative genomic hybridization (array-CGH) analysis of DNA samples prepared from each of the chromosomes revealed that these two chromosomes contained 296 and 263 segments, respectively, ranging from 1.5 kb to 784.3 kb in size, derived from different portions of chromosome 8. Among these segments, 242 were common in both aberrant chromosomes, but 75 were found to be chromosome-specific. Sequences of 263 junction sites connecting the ends of segments were determined using a PCR/Sanger-sequencing procedure. Overlapping microhomologies were found at 169 junction sites. Junction partners came from various portions of chromosome 8 and no biased pattern in the positional distribution of junction partners was detected. These structural characteristics suggested the occurrence of random fragmentation of the entire chromosome 8 followed by random rejoining of these fragments. Based on that, we proposed a model to explain how these aberrant chromosomes are formed. Through these structural analyses, it was demonstrated that the optimized chromosome isolation method described here can provide high-quality chromosomal DNA for high resolution array-CGH analysis and probably for massively parallel sequencing analysis.

  11. Biodiversity and its fragility in Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    PU Ying-shan; ZHANG Zhi-yi; PU Li-na; HUI Chao-mao

    2007-01-01

    In Yunnan, 8 major aspects of biodiversity and fragility in landforms, ecosystems, distribution populations, alien invasion, segregation, pollution and maladministration with various menace factors causing biodiversity loss have been described. It is revealed that the facts that the biodiversity and fragility coexists in this paper. Accordingly, 6 major countermeasures for effective conservation and rational utilization of the provincial biodiversity were suggested on the basis of thescientific development concepts, principles of nature protection,conservation biology, resource management and ethnobotany and present status in Yunnan with rich intangible resources such as climatic,ethnical and cultural diversity, etc.

  12. A New Fragile Watermark for Image

    Institute of Scientific and Technical Information of China (English)

    陆唯杰; 陈克非

    2003-01-01

    Fragile watermarking is a method to verify the integrity and authenticity of multimedia data. A new fragile watermark for image was proposed, which can be used in image verification applications. The paper first described the above two techniques, some of which will be used in the method. Then it described the embedding and authentication process and also analyzed the method to show how it can survive some attacks. The experimental results show that the proposed method doesn't need the watermark or original image on authentication side. It provides more security against attack, and can localize where the tempering has occurred.

  13. Extinction rate fragility in population dynamics.

    Science.gov (United States)

    Khasin, M; Dykman, M I

    2009-08-01

    Population extinction is of central interest for population dynamics. It may occur from a large rare fluctuation. We find that, in contrast to related large-fluctuation effects like noise-induced interstate switching, quite generally extinction rates in multipopulation systems display fragility, where the height of the effective barrier to be overcome in the fluctuation depends on the system parameters nonanalytically. We show that one of the best-known models of epidemiology, the susceptible-infectious-susceptible model, is fragile to total population fluctuations.

  14. Chromosome Analysis

    Science.gov (United States)

    1998-01-01

    Perceptive Scientific Instruments, Inc., provides the foundation for the Powergene line of chromosome analysis and molecular genetic instrumentation. This product employs image processing technology from NASA's Jet Propulsion Laboratory and image enhancement techniques from Johnson Space Center. Originally developed to send pictures back to earth from space probes, digital imaging techniques have been developed and refined for use in a variety of medical applications, including diagnosis of disease.

  15. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    Science.gov (United States)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  16. Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS)

    Science.gov (United States)

    ... Resources and Publications Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS): Overview Skip sharing on social media ... this: Page Content Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset condition (occurs ...

  17. Seismic Fragility of the LANL Fire Water Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mertz

    2007-03-30

    The purpose of this report is to present the results of a site-wide system fragility assessment. This assessment focuses solely on the performance of the water distribution systems that supply Chemical and Metallurgy Research (CMR), Weapons Engineering and Tritium Facility (WETF), Radioactive Liquid Waste Treatment Facility (RLWTF), Waste Characterization, Reduction, Repackaging Facility (WCRRF), and Transuranic Waste Inspectable Storage Project (TWISP). The analysis methodology is based on the American Lifelines Alliance seismic fragility formulations for water systems. System fragilities are convolved with the 1995 LANL seismic hazards to develop failure frequencies. Acceptance is determined by comparing the failure frequencies to the DOE-1020 Performance Goals. This study concludes that: (1) If a significant number of existing isolation valves in the water distribution system are closed to dedicate the entire water system to fighting fires in specific nuclear facilities; (2) Then, the water distribution systems for WETF, RLWTF, WCRRF, and TWISP meet the PC-2 performance goal and the water distribution system for CMR is capable of surviving a 0.06g earthquake. A parametric study of the WETF water distribution system demonstrates that: (1) If a significant number of valves in the water distribution system are NOT closed to dedicate the entire water system to fighting fires in WETF; (2) Then, the water distribution system for WETF has an annual probability of failure on the order of 4 x 10{sup -3} that does not meet the PC-2 performance goal. Similar conclusions are expected for CMR, RLWTF, WCRRF, and TWISP. It is important to note that some of the assumptions made in deriving the results should be verified by personnel in the safety-basis office and may need to be incorporated in technical surveillance requirements in the existing authorization basis documentation if credit for availability of fire protection water is taken at the PC-2 level earthquake levels

  18. Psychiatric treatment with people displaced in or from fragile states

    Directory of Open Access Journals (Sweden)

    Verity Buckley

    2013-05-01

    Full Text Available A fragile state is not an ideal environment for any professional to work within` – psychiatric, medical or otherwise. Psychiatrists working to assess psychological distress and mental health in fragile states, or with refugees from fragile states, need to adopt flexible approaches.

  19. Premature ovarian failure (POF) and fragile X premutation females: from POF to to fragile X carrier identification, from fragile X carrier diagnosis to POF association data.

    Science.gov (United States)

    Uzielli, M L; Guarducci, S; Lapi, E; Cecconi, A; Ricci, U; Ricotti, G; Biondi, C; Scarselli, B; Vieri, F; Scarnato, P; Gori, F; Sereni, A

    1999-05-28

    Early menopause in the fragile X carriers has been well documented in several reports. All surveys demonstrated that 13-25% of fragile X carriers experienced premature ovarian failure (POF), defined as menopause before the age of 40 years. In 1995 we started screening two groups of subjects as a part of a Fragile X Research Program: 1) women previously diagnosed as fragile X carriers from the register of our center and 2) women with POF and without a family history of fragile X or other forms of mental retardation. In this study we report the preliminary data collected from 75 fragile X families; in 30 of them, POF was present in one or several subjects, all of whom had a fragile X premutation. None of the women with a full mutation experienced POF in our series of patients. We also identified 89 families without a family history of fragile X or mental retardation, and there were 108 subjects who experienced POF, of which 6.5% had a fragile X premutation. This is 70-fold higher than the background prevalence of fragile X premutation in the Italian population and suggests an association with POF. These data confirm the results of other surveys.

  20. Compaction of Ductile and Fragile Grains

    Science.gov (United States)

    Creissac, S.; Pouliquen, O.; Dalloz-Dubrujeaud, B.

    2009-06-01

    The compaction of powders into tablets is widely used in several industries (cosmetics, food, pharmaceutics…). In all these industries, the composition of the initial powder is complex, and the behaviour under compaction is not well known, also the mechanical behaviour of the tablets. The aim of this paper is to understand the behaviour (pressure vs density) of a simplified media made of fragile and ductile powders, varying the relative ratio of each powder. Some compaction experiments were carried out with glass beads (fragile) and Polyethylen Glycol powder (ductile). We observe two typical behaviours, depending on the relative volumic fraction of each component. A transition is pointed out, observing the evolution of the slope of the curve pressure/density. This transition is explained by geometrical considerations during compaction. A model is proposed, based on the assumption that the studied media can be compare to a diphasic material with a continuous phase (the ductile powder) and a discrete phase (the fragile powder). The result of this model is compare to the experimental results of compaction, and give a good prediction of the behaviour of the different mixing, knowing the behaviour of the ductile and the fragile phase separately. These results were also interpreted in terms of Heckel parameter which characterizes the ability of the powder to deform plastically under compaction. Some mechanical tests were also performed to compare the mechanical resitance of the obtained tablets.

  1. Race and Ethnicity in Fragile Families

    Science.gov (United States)

    Hummer, Robert A.; Hamilton, Erin R.

    2010-01-01

    Robert Hummer and Erin Hamilton note that the prevalence of fragile families varies substantially by race and ethnicity. African Americans and Hispanics have the highest prevalence; Asian Americans, the lowest; and whites fall somewhere in the middle. The share of unmarried births is lower among most foreign-born mothers than among their U.S.-born…

  2. How to engage constructively with fragile states

    Directory of Open Access Journals (Sweden)

    Jon Bennett

    2013-05-01

    Full Text Available Donors have allocated increasing resources in fragile states tothe reform and/or rebuilding of the architecture of the state – suchas justice systems, the police and army, and the management ofministries – in efforts to support stability. This has been important for all sectors of society, including displaced people.

  3. Modeling Family Adaptation to Fragile X Syndrome

    Science.gov (United States)

    Raspa, Melissa; Bailey, Donald, Jr.; Bann, Carla; Bishop, Ellen

    2014-01-01

    Using data from a survey of 1,099 families who have a child with Fragile X syndrome, we examined adaptation across 7 dimensions of family life: parenting knowledge, social support, social life, financial impact, well-being, quality of life, and overall impact. Results illustrate that although families report a high quality of life, they struggle…

  4. Essays on financial fragility and regulation

    NARCIS (Netherlands)

    Ma, K.

    2013-01-01

    This thesis investigates various issues in regulation, with three chapters on financial fragility and banking regulation, and one chapter on competition policy. Chapter 2 studies banks’ herding driven by their need for market liquidity, highlighting a trade-off between systemic risk and liquidity cr

  5. Fragile Nucleosomes Influence Pol II Promoter Function.

    Science.gov (United States)

    Pradhan, Suman K; Xue, Yong; Carey, Michael F

    2015-11-05

    In this issue of Molecular Cell, Kubik et al. (2015) describe how the RSC chromatin remodeling complex collaborates with two DNA sequence motifs and sequence-specific general regulatory factors to assemble fragile nucleosomes at highly transcribed yeast Pol II promoters, and they distinguish these from promoters bearing stable nucleosomes.

  6. Multipartnered Fertility and Depression among Fragile Families

    Science.gov (United States)

    Turney, Kristin; Carlson, Marcia J.

    2011-01-01

    We used data from the Fragile Families and Child Wellbeing Study to examine the association between multipartnered fertility (MPF)--when parents have children with more than one partner--and depression. Random-effects models suggested that MPF is associated with a greater likelihood of depression, net of family structure and other covariates.…

  7. Strengthening Fragile Families through Research and Practice

    Science.gov (United States)

    Bembry, James X.

    2011-01-01

    Almost one third of all children in the United States are born to unmarried parents. This figure is even higher among poor and minority populations. Because of their heightened risk for economic and social problems and family dissolution, disadvantaged, unmarried parents have been called "fragile families." In 2002 the Bush administration…

  8. Tragedy on grade crossing: driver failure or systemic fragility?

    Science.gov (United States)

    Lopes, Manoela Gomes Reis; de Gouveia Vilela, Rodolfo Andrade; de Almeida, Ildeberto Muniz; Mioto, Odilamar Lopes; Takahashi, Mara Alice Batista Conti; Perin, Fernanda Oliveira

    2012-01-01

    In 2010, an accident occurred in Americana-SP, Brazil, involving two trains and one bus on a Grade Crossing, when 10 people died and 17 were injured including workers. This paper aims to analyze the accident using the Model of Analysis and Prevention of Work Accidents (MAPA). The method provides observation of work, interviews and analysis of documents to understand precedents of the event in the following stages: to understand the usual work from the involved people, the changes occurred in the system, the operation of barriers, managerial and organizational aspects. By the end, measures are suggested to avoid new occurrences. The accident took place at night in a site with insufficient lighting. The working conditions of bus drivers, train operators and watchmen are inadequate. There were only symbolic barriers (visual and acoustic signals) triggered manually by watchman upon train operator radio communication. The fragility of the barrier system associated to poor lighting and short time to trigger the signaling seem to play a critical role in the event. Contrary to the official report which resulted in guilt of the bus driver, the conclusion of the paper emphasizes the fragility of the safety system and the need of level crossing reproject.

  9. Bridge-induced chromosome translocation in yeast relies upon a Rad54/Rdh54-dependent, Pol32-independent pathway.

    Directory of Open Access Journals (Sweden)

    Valentina Tosato

    Full Text Available While in mammalian cells the genetic determinism of chromosomal translocation remains unclear, the yeast Saccharomyces cerevisiae has become an ideal model system to generate ad hoc translocations and analyze their cellular and molecular outcome. A linear DNA cassette carrying a selectable marker flanked by perfect homologies to two chromosomes triggers a bridge-induced translocation (BIT in budding yeast, with variable efficiency. A postulated two-step process to produce BIT translocants is based on the cooperation between the Homologous Recombination System (HRS and Break-Induced Replication (BIR; however, a clear indication of the molecular factors underlying the genetic mechanism is still missing. In this work we provide evidence that BIT translocation is elicited by the Rad54 helicase and completed by a Pol32-independent replication pathway. Our results demonstrate also that Rdh54 is involved in the stability of the translocants, suggesting a mitotic role in chromosome pairing and segregation. Moreover, when RAD54 is over-expressed, an ensemble of secondary rearrangements between repeated DNA tracts arise after the initial translocation event, leading to severe aneuploidy with loss of genetic material, which prompts the identification of fragile sites within the yeast genome.

  10. Chromosomal painting and ZW sex chromosomes differentiation in Characidium (Characiformes, Crenuchidae

    Directory of Open Access Journals (Sweden)

    Artoni Roberto F

    2011-07-01

    Full Text Available Abstract Background The Characidium (a Neotropical fish group have a conserved diploid number (2n = 50, but show remarkable differences among species and populations in relation to sex chromosome systems and location of nucleolus organizer regions (NOR. In this study, we isolated a W-specific probe for the Characidium and characterized six Characidium species/populations using cytogenetic procedures. We analyzed the origin and differentiation of sex and NOR-bearing chromosomes by chromosome painting in populations of Characidium to reveal their evolution, phylogeny, and biogeography. Results A W-specific probe for efficient chromosome painting was isolated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR amplification of W chromosomes from C. gomesi. The W probe generated weak signals dispersed on the proto sex chromosomes in C. zebra, dispersed signals in both W and Z chromosomes in C. lauroi and, in C. gomesi populations revealed a proximal site on the long arms of the Z chromosome and the entire W chromosome. All populations showed small terminal W probe sites in some autosomes. The 18S rDNA revealed distinctive patterns for each analyzed species/population with regard to proto sex chromosome, sex chromosome pair, and autosome location. Conclusions The results from dual-color fluorescence in situ hybridization (dual-color FISH using W and 18S rDNA probes allowed us to infer the putative evolutionary pathways for the differentiation of sex chromosomes and NORs, from structural rearrangements in a sex proto-chromosome, followed by gene erosion and heterochromatin amplification, morphological differentiation of the sex chromosomal pair, and NOR transposition, giving rise to the distinctive patterns observed among species/populations of Characidium. Biogeographic isolation and differentiation of sex chromosomes seem to have played a major role in the speciation process in this group of fish.

  11. Diagnostic Yield of Chromosomal Microarray Analysis in an Autism Primary Care Practice: Which Guidelines to Implement?

    Science.gov (United States)

    McGrew, Susan G.; Peters, Brittany R.; Crittendon, Julie A.; Veenstra-VanderWeele, Jeremy

    2012-01-01

    Genetic testing is recommended for patients with ASD; however specific recommendations vary by specialty. American Academy of Pediatrics and American Academy of Neurology guidelines recommend G-banded karyotype and Fragile X DNA. The American College of Medical Genetics recommends Chromosomal Microarray Analysis (CMA). We determined the yield of…

  12. Persistence of Breakage in Specific Chromosome Bands 6 Years after Acute Exposure to Oil

    Science.gov (United States)

    Francés, Alexandra; Hildur, Kristin; Barberà, Joan Albert; Rodríguez-Trigo, Gema; Zock, Jan-Paul; Giraldo, Jesús; Monyarch, Gemma; Rodriguez-Rodriguez, Emma; de Castro Reis, Fernanda; Souto, Ana; Gómez, Federico P.; Pozo-Rodríguez, Francisco; Templado, Cristina; Fuster, Carme

    2016-01-01

    Background The identification of breakpoints involved in chromosomal damage could help to detect genes involved in genetic disorders, most notably cancer. Until now, only one published study, carried out by our group, has identified chromosome bands affected by exposure to oil from an oil spill. In that study, which was performed two years after the initial oil exposure in individuals who had participated in clean-up tasks following the wreck of the Prestige, three chromosomal bands (2q21, 3q27, 5q31) were found to be especially prone to breakage. A recent follow-up study, performed on the same individuals, revealed that the genotoxic damage had persisted six years after oil exposure. Objectives To determine whether there exist chromosome bands which are especially prone to breakages and to know if there is some correlation with those detected in the previous study. In addition, to investigate if the DNA repair problems detected previously persist in the present study. Design Follow-up study performed six years after the Prestige oil spill. Setting Fishermen cooperatives in coastal villages. Participants Fishermen highly exposed to oil spill who participated in previous genotoxic study six years after the oil. Measurements Chromosome damage in peripheral lymphocytes. For accurate identification of the breakpoints involved in chromosome damage of circulating lymphocytes, a sequential stain/G-banding technique was employed. To determine the most break-prone chromosome bands, two statistical methods, the Fragile Site Multinomial and the chi-square tests (where the bands were corrected by their length) were used. To compare the chromosome lesions, structural chromosome alterations and gaps/breaks between two groups of individuals we used the GEE test which takes into account a possible within-individual correlation. Dysfunctions in DNA repair mechanisms, expressed as chromosome damage, were assessed in cultures with aphidicolin by the GEE test. Results Cytogenetic

  13. Mouse models of the fragile x premutation and the fragile X associated tremor/ataxia syndrome.

    Science.gov (United States)

    Hunsaker, Michael R; Arque, Gloria; Berman, Robert F; Willemsen, Rob; Hukema, Renate K

    2012-01-01

    The use of mutant mouse models of neurodevelopmental and neurodegenerative disease is essential in order to understand the pathogenesis of many genetic diseases such as fragile X syndrome and fragile X-associated tremor/ataxia syndrome (FXTAS). The choice of which animal model is most suitable to mimic a particular disease depends on a range of factors, including anatomical, physiological, and pathological similarities; presence of orthologs of genes of interest; and conservation of basic cell biological and metabolic processes. In this chapter, we will discuss two mouse models of the fragile X premutation which have been generated to study the pathogenesis of FXTAS and the effects of potential therapeutic interventions. Behavioral, molecular, neuropathological, and endocrine features of the mouse models and their relation to human FXTAS are discussed.

  14. Complete Genome Sequence of Germline Chromosomally Integrated Human Herpesvirus 6A and Analyses Integration Sites Define a New Human Endogenous Virus with Potential to Reactivate as an Emerging Infection.

    Science.gov (United States)

    Tweedy, Joshua; Spyrou, Maria Alexandra; Pearson, Max; Lassner, Dirk; Kuhl, Uwe; Gompels, Ursula A

    2016-01-15

    Human herpesvirus-6A and B (HHV-6A, HHV-6B) have recently defined endogenous genomes, resulting from integration into the germline: chromosomally-integrated "CiHHV-6A/B". These affect approximately 1.0% of human populations, giving potential for virus gene expression in every cell. We previously showed that CiHHV-6A was more divergent than CiHHV-6B by examining four genes in 44 European CiHHV-6A/B cardiac/haematology patients. There was evidence for gene expression/reactivation, implying functional non-defective genomes. To further define the relationship between HHV-6A and CiHHV-6A we used next-generation sequencing to characterize genomes from three CiHHV-6A cardiac patients. Comparisons to known exogenous HHV-6A showed CiHHV-6A genomes formed a separate clade; including all 85 non-interrupted genes and necessary cis-acting signals for reactivation as infectious virus. Greater single nucleotide polymorphism (SNP) density was defined in 16 genes and the direct repeats (DR) terminal regions. Using these SNPs, deep sequencing analyses demonstrated superinfection with exogenous HHV-6A in two of the CiHHV-6A patients with recurrent cardiac disease. Characterisation of the integration sites in twelve patients identified the human chromosome 17p subtelomere as a prevalent site, which had specific repeat structures and phylogenetically related CiHHV-6A coding sequences indicating common ancestral origins. Overall CiHHV-6A genomes were similar, but distinct from known exogenous HHV-6A virus, and have the capacity to reactivate as emerging virus infections.

  15. Chromosome aberrations in Japanese fishermen exposed to fallout radiation 420-1200 km distant from the nuclear explosion test site at Bikini Atoll: report 60 years after the incident.

    Science.gov (United States)

    Tanaka, Kimio; Ohtaki, Megu; Hoshi, Masaharu

    2016-08-01

    During the period from March to May, 1954, the USA conducted six nuclear weapon tests at the "Bravo" detonation sites at the Bikini and Enewetak Atolls, Marshall Islands. At that time, the crew of tuna fishing boats and cargo ships that were operating approximately 150-1200 km away from the test sites were exposed to radioactive fallout. The crew of the fishing boats and those on cargo ships except the "5th Fukuryu-maru" did not undergo any health examinations at the time of the incident. In the present study, chromosome aberrations in peripheral blood lymphocytes were examined in detail by the G-banding method in 17 crew members from 8 fishing boats and 2 from one cargo ship, 60 years after the tests. None of the subjects examined had suffered from cancer. The percentages of both stable-type aberrations such as translocation, inversion and deletion, and unstable-type aberrations such as dicentric and centric ring in the study group were significantly higher (1.4- and 2.3-fold, respectively) than those in nine age-matched controls. In the exposed and control groups, the percentages of stable-type aberrations were 3.35 % and 2.45 %, respectively, and the numbers of dicentric and centric ring chromosomes per 100 cells were 0.35 and 0.15, respectively. Small clones were observed in three members of the exposed group. These results suggest that the crews were exposed to slightly higher levels of fallout than had hitherto been assumed.

  16. Comprehensive analysis of ultrasonic vocalizations in a mouse model of fragile X syndrome reveals limited, call type specific deficits.

    Directory of Open Access Journals (Sweden)

    Snigdha Roy

    Full Text Available Fragile X syndrome (FXS is a well-recognized form of inherited mental retardation, caused by a mutation in the fragile X mental retardation 1 (Fmr1 gene. The gene is located on the long arm of the X chromosome and encodes fragile X mental retardation protein (FMRP. Absence of FMRP in fragile X patients as well as in Fmr1 knockout (KO mice results, among other changes, in abnormal dendritic spine formation and altered synaptic plasticity in the neocortex and hippocampus. Clinical features of FXS include cognitive impairment, anxiety, abnormal social interaction, mental retardation, motor coordination and speech articulation deficits. Mouse pups generate ultrasonic vocalizations (USVs when isolated from their mothers. Whether those social ultrasonic vocalizations are deficient in mouse models of FXS is unknown. Here we compared isolation-induced USVs generated by pups of Fmr1-KO mice with those of their wild type (WT littermates. Though the total number of calls was not significantly different between genotypes, a detailed analysis of 10 different categories of calls revealed that loss of Fmr1 expression in mice causes limited and call-type specific deficits in ultrasonic vocalization: the carrier frequency of flat calls was higher, the percentage of downward calls was lower and that the frequency range of complex calls was wider in Fmr1-KO mice compared to their WT littermates.

  17. Genetic linkage heterogeneity in the fragile X syndrome.

    Science.gov (United States)

    Brown, W T; Gross, A C; Chan, C B; Jenkins, E C

    1985-01-01

    Genetic linkage between a factor IX DNA restriction fragment length polymorphism (RFLP) and the fragile X chromosome marker was analyzed in eight fragile X pedigrees and compared to eight previously reported pedigrees. A large pedigree with apparently full penetrance in all male members showed a high frequency of recombination. A lod score of -7.39 at theta = 0 and a maximum score of 0.26 at theta = 0.32 were calculated. A second large pedigree with a nonpenetrant male showed tight linkage with a maximum lod score of 3.13 at theta = 0, a result similar to one large pedigree with a nonpenetrant male previously reported. The differences in lod scores seen in these large pedigrees suggested there was genetic heterogeneity in linkage between families which appeared to relate to the presence of nonpenetrant males. The combined lod score for the three pedigrees with nonpenetrant males was 6.84 at theta = 0. For the 13 other pedigrees without nonpenetrant males the combined lod score was -21.81 at theta = 0, with a peak of 0.98 at theta = 0.28. When lod scores from all 16 families were combined, the value was -15.14 at theta = 0 and the overall maximum was 5.13 at theta = 0.17. To determine whether genetic heterogeneity was present, three statistical tests for heterogeneity were employed. First, a "predivided-sample" test was used. The 16 pedigrees were divided into two classes, NP and P, based upon whether or not any nonpenetrant males were detected in the pedigree. This test gave evidence for significant genetic heterogeneity whether the three large pedigrees with seven or more informative males (P less than 0.005), the eight pedigrees with three informative males (P less than 0.001), or all 16 pedigrees (P less than 0.001) were included in the analysis. Second, Morton's large sample test was employed. Significant heterogeneity was present when the analysis was restricted to the three large pedigrees (P less than 0.025), or to the eight pedigrees with informative males

  18. Treatment of Fragile X Syndrome with a Neuroactive Steroid

    Science.gov (United States)

    2015-08-01

    ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER University of California, Davis MIND Institute 2825 50th Street...presentation produced a manuscript. New treatments for fragile X syndrome and autism , Seminar, Hautepierre Hospital, Strasbourg, France, 3/9/2015...Fragile X Conference, Karolinska University Hospital, Stockholm, Sweden, 5/7/2015. New treatments for fragile X and autism , Conference on Rare

  19. Chromosomal Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-07-01

    Full Text Available The prevalence of fragile X syndrome, velocardiofacial syndrome (VCFS, and other cytogenetic abnormalities among 100 children (64 boys with combined type ADHD and normal intelligence was assessed at the NIMH and Georgetown University Medical Center.

  20. Two mutations in the locus control region hypersensitivity site-2 (5' HS-2) of haplotype 19 beta s chromosomes alter binding of trans-acting factors.

    Science.gov (United States)

    Morgan, J C; Scott, D F; Lanclos, K D

    1996-01-01

    There are five major haplotypes associated with sickle cell anemia (SS). Individuals homozygous for haplotypes 3 (Senegal) and 31 (Saudi Arabian) have high fetal hemoglobin (HbF) levels (15 to 30% of total hemoglobin) whereas individuals homozygous for haplotypes 17 (Cameroon), 19 (Benin), and 20 (Bantu) have low HbF levels (1 to 10%). We previously identified several point mutations in the LCR 5'HS-2 that were specific for haplotype 19 beta s chromosomes (compared to the GenBank HUMHBB reference sequence, T-->G at position 8580, A-->G at position 8598, and A-->T at position 9114). We postulated that one or more of these mutations may alter the binding of specific trans-acting factors and ultimately affect the expression of HbF in these sickle cell patients. We performed gel mobility shift assays using 32P-end-labeled double-stranded 19mers corresponding to each of the LCR 5'HS-2 normal (GenBank) and mutant sequences. Nuclear extracts prepared from HeLa and HEL cells were used in our experiments and neither the normal nor mutant sequence at position 8580 bound trans-acting factors in either nuclear extract. The 8598 mutant increased binding of Sp1; using purified protein and both nuclear extracts. HEL extracts were used to quantify the increase in Sp1 binding to the 8598 mutation and we found an increase in binding of 66 and 47%, respectively, in two shifted bands. The 9114 mutation sharply decreased binding of an unknown trans-acting factor by 74%. This factor was present in both HeLa and HEL nuclear extracts.

  1. Fragile states and protection under the 1969 African Refugee Convention

    Directory of Open Access Journals (Sweden)

    Tamara Wood

    2013-05-01

    Full Text Available Current practice in African states highlights both the potential andthe limitations of the 1969 African Refugee Convention in providingprotection to persons displaced from fragile states.

  2. What Should You Know about Fragile X Syndrome (FXS)?

    Science.gov (United States)

    ... treatments. Associated Disorders Fragile X-associated disorders. Articles Scientific articles. Free Materials View and print free materials. Data & Statistics Data and statistics highlights. Links to Other Websites ...

  3. Germline mosaicism at the fragile X locus

    Energy Technology Data Exchange (ETDEWEB)

    Papp, A.C.; Snyder, P.J.; Sedra, M.S. [Ohio State Univ., Columbus, OH (United States)] [and others

    1994-09-01

    The fragile X full mutation, which is associated with the phenotypic expression of the disorder, is characterized by an expansion of CGG repeat and hypermethylation of the CpG island adjacent to the FMR1 gene. New mutations leading to amplification of the CGG repeat have not been reported. We have identified a fragile X syndrome pedigree where the disorder is associated with a molecular deletion. The deletion was present in the DNA of two affected sons but was absent in the mother`s somatic cell (lymphocyte) DNA. This was confirmed by dosage analysis of the Southern blot using StB12-3 and an additional probe against the dystrophin gene and by PCR analysis of DXS548 alleles. The results are consistent with the deletion arising as a postzygotic event in the mother, who therefore is germinally mosaic. The case reported here clearly demonstrates that FMR1 deletions, unlike the expansions, are not always inherited and the finding of heterozygosity or normal dosage from lymphocyte DNA in the mother of a deletion case does not necessarily rule out the possibility of having a second affected child. The deletion of FMR1 gene may be responsible for a small but significant number of fragile X cases. Therefore, it is imperative that those involved in genetic counseling recognize this diagnostic pitfall. Since it depends upon the size of the mutant clone in the mosaic mother, the exact recurrence risk in germline carriers is unknown. However, prenatal and carrier testing should be performed independently of the outcome of the mother. Furthermore, it is possible that the deletion may not be restricted to the germline, and therefore the mother may actually be a somatic mosaic.

  4. New Semi-Fragile Authentication Watermarking

    Institute of Scientific and Technical Information of China (English)

    孙鑫; 易开祥; 等

    2002-01-01

    In this paper we propse a semi-fragile watermarking scheme,which can be used for image authentication.Let the original image be performed by l-level discrete wavelet transformation.An approximate wavelet coefficient matrix of the original image and real-value chaotic sequences are than used to generate the content-based and secure watermark.The watermark is embedded into original image by using by using HVS.The tamper detection can idantify the tampered region of the received watermarked image,Experimental results are given.

  5. Meiotic chromosome abnormalities in human spermatogenesis.

    Science.gov (United States)

    Martin, Renée H

    2006-08-01

    The last few years have witnessed an explosion in the information about chromosome abnormalities in human sperm and the meiotic events that predispose to these abnormalities. We have determined that all chromosomes are susceptible to nondisjunction, but chromosomes 21 and 22 and, especially, the sex chromosomes have an increased frequency of aneuploidy. Studies are just beginning on the effects of potential mutagens on the chromosomal constitution of human sperm. The effects of pesticides and cancer therapeutic agents have been reviewed. In the last decade, there has been a great impetus to study chromosome abnormalities in sperm from infertile men because the advent of intracytoplasmic sperm injection (ICSI) made it possible for these men to father pregnancies. A large number of studies have demonstrated that infertile men have an increased frequency of chromosomally abnormal sperm and children, even when they have a normal somatic karyotype. Meiotic studies on the pachytene stage of spermatogenesis have demonstrated that infertile men have impaired chromosome synapsis, a significantly decreased frequency of recombination, and an increased frequency of chromosomes completely lacking a recombination site. Such errors make these cells susceptible to meiotic arrest and the production of aneuploid gametes.

  6. Repair of I-SceI induced DSB at a specific site of chromosome in human cells: influence of low-dose, low-dose-rate gamma-rays.

    Science.gov (United States)

    Yatagai, Fumio; Suzuki, Masao; Ishioka, Noriaki; Ohmori, Hitoshi; Honma, Masamitsu

    2008-11-01

    We investigated the influence of low-dose, low-dose-rate gamma-ray irradiation on DNA double strand break (DSB) repair in human lymphoblastoid TK6 cells. A single DSB was introduced at intron 4 of the TK+ allele (chromosome 17) by transfection with the I-SceI expression vector pCBASce. We assessed for DSB repair due to non-homologous end-joining (NHEJ) by determining the generation of TK-deficient mutants in the TK6 derivative TSCE5 (TK +/-) carrying an I-SceI recognition site. We similarly estimated DSB repair via homologous recombination (HR) at the same site in the derived compound heterozygote (TK-/-) cell line TSCER2 that carries an additional point mutation in exon 5. The NHEJ repair of DSB was barely influenced by pre-irradiation of the cells with 30 mGy gamma-rays at 1.2 mGy h(-1). DSB repair by HR, in contrast, was enhanced by approximately 50% after pre-irradiation of the cells under these conditions. Furthermore, when I-SceI digestion was followed by irradiation at a dose of 8.5 mGy, delivered at a dose rate of only 0.125 mGy h(-1), HR repair efficiency was enhanced by approximately 80%. This experimental approach can be applied to characterize DSB repair in the low-dose region of ionizing radiation.

  7. Undetected sex chromosome aneuploidy by chromosomal microarray.

    Science.gov (United States)

    Markus-Bustani, Keren; Yaron, Yuval; Goldstein, Myriam; Orr-Urtreger, Avi; Ben-Shachar, Shay

    2012-11-01

    We report on a case of a female fetus found to be mosaic for Turner syndrome (45,X) and trisomy X (47,XXX). Chromosomal microarray analysis (CMA) failed to detect the aneuploidy because of a normal average dosage of the X chromosome. This case represents an unusual instance in which CMA may not detect chromosomal aberrations. Such a possibility should be taken into consideration in similar cases where CMA is used in a clinical setting.

  8. Fragility Fractures in Patients with Psoriatic Arthritis.

    Science.gov (United States)

    Del Puente, Antonio; Esposito, Antonella; Costa, Luisa; Benigno, Carla; Del Puente, Aurora; Foglia, Francesca; Oriente, Alfonso; Bottiglieri, Paolo; Caso, Francesco; Scarpa, Raffaele

    2015-11-01

    Psoriatic arthritis (PsA) can have peculiar effects on bone, including mechanisms of bone loss such as erosions, but also of bone formation, such as ankylosis or periostitis. The aim of the present study was to describe the prevalence of fractures in patients with PsA as compared to healthy controls and to investigate determinants of fractures among cases. For both cases and controls, radiographs were read to identify vertebral fractures (VF), and the presence of femoral neck or other nonvertebral fractures was obtained from patients' medical history. The prevalence of fragility fractures on radiographic readings did not differ between cases and controls. The number of subjects showing a VF was 33 (36%) among PsA patients and 36 (36%) among controls, with a prevalence of severe VF of 8% among cases and 4% among controls. Controlling for covariates in a logistic model, the only variables showing a significant correlation with the presence of nonvertebral fractures (NVF) were disease duration (p=0.02), age (p=0.03), and bone mineral density at femoral neck (inverse correlation, p=0.04). Fractures should be carefully considered when evaluating the global picture of the patient with PsA for their contribution to the "fragility" profile.

  9. Fragile X syndrome in incestuous families

    Energy Technology Data Exchange (ETDEWEB)

    Seemanova, E. [Charles Univ., Prague (Czech Republic)

    1996-11-11

    Reed suggested the investigation of children 219 from incestuous unions as a method for calculation of the detrimental heterozygosity of man. Some studies of latent genetics load in man have been based on the comparison of health status of incestuous children with their half-sibs born to the same mothers in matings with nonconsanguineous partners. These studies were limited to the detection of autosomal-recessive genes leading to abnormal phenotypes or mental deficiency in homozygotes. The highest coefficient of inbreeding in human beings is 1/4 in offspring of incestuous matings: hence, the high proportion of affected homozygotes and low incidence of affected individuals among their maternal half-sibs. Mental deficiency in incestuous children represents not only cases of simple recessive inheritance. Recently, we observed three incestuous families in which fragile X syndrome was detected. The fra(X) children were born to carriers from incestuous unions as well as to unrelated partners. Therefore, we recommend use of incestuous children and their maternal half-sibs as a control group for studies estimating latent genetic load after investigation for fra(X). The incidence of fra(X) syndrome is high, and mental retardation in heterozygotes is uncommon. Both of these factors can play a role in the occurrence of incest, and in pregnancy at young age, as well as in multiple partnerships. Families of heterozygotes for fragile X should be excluded from the material for the calculation of human latent detrimental (autosomal-recessive) genetic load. 3 refs., 3 figs.

  10. Synaptic vesicle dynamic changes in a model of fragile X

    NARCIS (Netherlands)

    Broek, Jantine A C; Lin, Zhanmin; de Gruiter, H Martijn; van 't Spijker, Heleen; Haasdijk, Elize D; Cox, David; Ozcan, Sureyya; van Cappellen, Gert W A; Houtsmuller, Adriaan B; Willemsen, Rob; de Zeeuw, Chris I; Bahn, Sabine

    2016-01-01

    BACKGROUND: Fragile X syndrome (FXS) is a single-gene disorder that is the most common heritable cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorders (ASD). FXS is caused by an expansion of trinucleotide repeats in the promoter region of the fragile X m

  11. Fragility curves for bridges under differential support motions

    DEFF Research Database (Denmark)

    Konakli, Katerina

    2012-01-01

    This paper employs the notion of fragility to investigate the seismic vulnerability of bridges subjected to spatially varying support motions. Fragility curves are developed for four highway bridges in California with vastly different structural characteristics. The input in this analysis consists...

  12. Dilemmas in counselling females with the fragile X syndrome

    NARCIS (Netherlands)

    B.B.A. de Vries (Bert); H.M. van den Boer-van den Berg; M.F. Niermeijer (Martinus); A. Tibben (Arend)

    1999-01-01

    textabstractThe dilemmas in counselling a mildly retarded female with the fragile X syndrome and her retarded partner are presented. The fragile X syndrome is an X linked mental retardation disorder that affects males and, often less severely, females. Affected females

  13. Numerical computation of fragility curves for NPP equipment

    Energy Technology Data Exchange (ETDEWEB)

    Zentner, I., E-mail: irmela.zentner@edf.f [LaMSID, Laboratory for the Mechanics of Aging Industrial Structures, UMR EDF/CNRS, 1, av. du General de Gaulle, 92141 Clamart (France)

    2010-06-15

    The seismic probabilistic risk assessment (PRA) methodology is a popular approach for evaluating the risk of failure of engineering structures due to earthquake. In this framework, fragility curves express the conditional probability of failure of a structure or component for a given seismic input motion parameter A, such as peak ground acceleration (PGA) or spectral acceleration. The failure probability due to a seismic event is obtained by convolution of fragility curves with seismic hazard curves. In general, a log-normal model is used in order to estimate fragilities. In nuclear engineering practice, these fragilities are determined using safety factors with respect to design earthquake. This approach allows to determine fragility curves based on design study but largely draws on expert judgement and simplifying assumptions. When a more realistic assessment of seismic fragility is needed, simulation-based statistical estimation of fragility curves is more appropriate. In this paper, we will discuss statistical estimation of parameters of fragility curves and present results obtained for a reactor coolant system of nuclear power plant. We have performed non-linear dynamic response analyses using artificially generated strong motion time histories. Uncertainties due to seismic loads as well as model uncertainties are taken into account and propagated using Monte Carlo simulation.

  14. Fragile X-Associated Primary Ovarian Insufficiency (FXPOI): Condition Information

    Science.gov (United States)

    ... Association of FMR1 repeat size with ovarian dysfunction. Human Reproduction, 20 , 402-412. [top] Partington, M. W., York Moore. D., & Turner, G. M. (1996). Confirmation of early menopause in fragile X carriers. American Journal of Medical Genetics, 64 , 370372. [top] National Fragile X Foundation. (n. ...

  15. Financial Inclusion and Financial Fragility: An Empirical Note

    OpenAIRE

    Ghosh, Saibal

    2008-01-01

    Using data on Indian state-owned banks for 1997-2007, the article tests the relationship between financial inclusion and financial fragility. The findings reveal that these variables are intertwined, with each tending to reinforce the other. More importantly, financial fragility is a non-linear determinant of both availability and use of banking services.

  16. 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...... changes with that of introns, between chrZ and autosomes or regions with increasing ages of becoming Z-linked, therefore codon usage bias in birds is probably driven by the mutational bias. On the other hand, Z chromosomes also evolve significantly faster at nonsynonymous sites relative to autosomes...

  17. Chromosome Disorder Outreach

    Science.gov (United States)

    ... BLOG Join Us Donate You are not alone. Chromosome Disorder Outreach, Inc. is a non-profit organization, ... Support For all those diagnosed with any rare chromosome disorder. Since 1992, CDO has supported the parents ...

  18. Affected chromosome homeostasis and genomic instability of clonal yeast cultures.

    Science.gov (United States)

    Adamczyk, Jagoda; Deregowska, Anna; Panek, Anita; Golec, Ewelina; Lewinska, Anna; Wnuk, Maciej

    2016-05-01

    Yeast cells originating from one single colony are considered genotypically and phenotypically identical. However, taking into account the cellular heterogeneity, it seems also important to monitor cell-to-cell variations within a clone population. In the present study, a comprehensive yeast karyotype screening was conducted using single chromosome comet assay. Chromosome-dependent and mutation-dependent changes in DNA (DNA with breaks or with abnormal replication intermediates) were studied using both single-gene deletion haploid mutants (bub1, bub2, mad1, tel1, rad1 and tor1) and diploid cells lacking one active gene of interest, namely BUB1/bub1, BUB2/bub2, MAD1/mad1, TEL1/tel1, RAD1/rad1 and TOR1/tor1 involved in the control of cell cycle progression, DNA repair and the regulation of longevity. Increased chromosome fragility and replication stress-mediated chromosome abnormalities were correlated with elevated incidence of genomic instability, namely aneuploid events-disomies, monosomies and to a lesser extent trisomies as judged by in situ comparative genomic hybridization (CGH). The tor1 longevity mutant with relatively balanced chromosome homeostasis was found the most genomically stable among analyzed mutants. During clonal yeast culture, spontaneously formed abnormal chromosome structures may stimulate changes in the ploidy state and, in turn, promote genomic heterogeneity. These alterations may be more accented in selected mutated genetic backgrounds, namely in yeast cells deficient in proper cell cycle regulation and DNA repair.

  19. 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 si

  20. ZEBRAFISH CHROMOSOME-BANDING

    NARCIS (Netherlands)

    PIJNACKER, LP; FERWERDA, MA

    1995-01-01

    Banding techniques were carried out on metaphase chromosomes of zebrafish (Danio rerio) embryos. The karyotypes with the longest chromosomes consist of 12 metacentrics, 26 submetacentrics, and 12 subtelocentrics (2n = 50). All centromeres are C-band positive. Eight chromosomes have a pericentric C-b

  1. Entanglement and decoherence: fragile and robust entanglement

    CERN Document Server

    Novotný, Jaroslav; Jex, Igor

    2011-01-01

    The destruction of entanglement of open quantum systems by decoherence is investigated in the asymptotic long-time limit. Starting from a general and analytically solvable decoherence model which does not involve any weak-coupling or Markovian assumption it is shown that two fundamentally different classes of entangled states can be distinguished. Quantum states of the first class are fragile against decoherence so that they can be disentangled asymptotically even if coherences between pointer states are still present. Quantum states of the second type are robust against decoherence. Asymptotically they can be disentangled only if also decoherence is perfect. A simple criterion for identifying these two classes on the basis of two-qubit entanglement is presented.

  2. Pathological Plasticity in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Brandon S. Martin

    2012-01-01

    Full Text Available Deficits in neuronal plasticity are common hallmarks of many neurodevelopmental disorders. In the case of fragile-X syndrome (FXS, disruption in the function of a single gene, FMR1, results in a variety of neurological consequences directly related to problems with the development, maintenance, and capacity of plastic neuronal networks. In this paper, we discuss current research illustrating the mechanisms underlying plasticity deficits in FXS. These processes include synaptic, cell intrinsic, and homeostatic mechanisms both dependent on and independent of abnormal metabotropic glutamate receptor transmission. We place particular emphasis on how identified deficits may play a role in developmental critical periods to produce neuronal networks with permanently decreased capacity to dynamically respond to changes in activity central to learning, memory, and cognition in patients with FXS. Characterizing early developmental deficits in plasticity is fundamental to develop therapies that not only treat symptoms but also minimize the developmental pathology of the disease.

  3. Fragile X syndrome and the amygdala.

    Science.gov (United States)

    Suvrathan, Aparna; Chattarji, Sumantra

    2011-06-01

    Fragile X syndrome (FXS) is the most commonly inherited form of mental impairment and autism. Current understanding of the molecular and cellular mechanisms underlying FXS symptoms is derived mainly from studies on the hippocampus and cortex. However, FXS is also associated with strong emotional symptoms, which are likely to involve changes in the amygdala. Unfortunately, the synaptic basis of amygdalar dysfunction in FXS remains largely unexplored. Here we describe recent findings from mouse models of FXS that have identified synaptic defects in the basolateral amygdala that are in many respects distinct from those reported earlier in the hippocampus. Long-term potentiation and surface expression of AMPA-receptors are impaired. Further, presynaptic defects are seen at both excitatory and inhibitory synapses. Remarkably, some of these synaptic defects in the amygdala are also amenable to pharmacological rescue. These results also underscore the need to modify the current hippocampus-centric framework to better explain FXS-related synaptic dysfunction in the amygdala.

  4. FMR-1 CGG transitions in male and female carriers of fragile X

    Energy Technology Data Exchange (ETDEWEB)

    Nolin, S.L.; Lewis, F.A. III; Ye, L.L. [New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States)] [and others

    1994-09-01

    We have conducted a preliminary analysis of the CGG transitions observed among the offspring of fragile X male and female carriers using the PCR method of Brown et al. A strong familial clustering was observed in maternal inheritance of the fragile X chromosome. Fifty-eight premutation females passed their fragile X alleles to mutiple offspring (total 134). Forty-nine of these women had 106 children with the full mutation. Nine mothers (2 in the 60-69 repeat range, 6 in the 80-89 range, 1 in the 90-99 range) had a total of 19 premutation and 3 full mutation children. These data suggest that a premutation carrier with 1 premutation child has a reduced risk for full mutation offspring independent of her CGG repeat size. Familial clustering was also observed in transmitting males. The daughters of transmitting males showed surprisingly little variation in CGG repeat size among each set of daughters. In twelve sibling sets, the daughters were within 10 CGGs of each other, 6 sets were within 11-18 repeats, and one set was within 40 repeats. Taken together, the male and female carrier data support the concept of a sequence or structure within or close to the CGG repeat which influences the expansion of the repeat during its transmission from parent to child. We also found that in transmitting males with > 90 repeats, the repeat was often meiotically unstable. In 5 of these males, 44% (7/16) meioses showed a reduction 2-20 CGGs inherited and all 5 fathers had at least 1 daughter with a size reduction. This finding suggests that repeats > 90 may not be stably transmitted in spermatocytes.

  5. Characterization of the staphylococcal cassette chromosome mec insertion site in 108 isolates lacking the mecA gene and identified as methicillin-resistant Staphylococcus aureus by the Xpert MRSA assay.

    Science.gov (United States)

    Stojanov, M; Blanc, D S

    2014-11-01

    During a 3-year period, 848 patients were detected as carriers of methicillin-resistant Staphylococcus aureus (MRSA) by the Xpert MRSA assay (Cepheid). Among them, 108 patients (12.7 %) were colonized with strains showing methicillin-susceptible phenotypes and absence of the mecA gene, despite being positive with the rapid polymerase chain reaction (PCR) assay. DNA sequences of the staphylococcal cassette chromosome mec (SCCmec) insertion site of these "false-positive" strains was determined by direct sequencing of the genomic DNA. More than half (53.7 %) of the strains had DNA sequences unrelated to either SCC or SCCmec and one-third had DNA sequences related to non-mec SCC. Only 10.2 % of the strains carried sequences related to SCCmec, suggesting that a sequence containing the mecA gene was lost from an SCCmec. These findings differ from the general idea that all methicillin-susceptible S. aureus having positive Xpert MRSA assay results are essentially MRSA that lost the mecA gene.

  6. Fragility curves of concrete bridges retrofitted by column jacketing

    Science.gov (United States)

    Shinozuka, Masanobu; Kim, Sang-Hoon; Kushiyama, Shigeru; Yi, Jin-Hak

    2002-12-01

    The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans’ bridges not retrofitted by column jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA. The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA) SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges. The improvement in the fragility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.

  7. Seismic fragility of nuclear power plant components (Phase II)

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, K.K.; Hofmayer, C.H.; Kassir, M.K.; Pepper, S.E. (Brookhaven National Lab., Upton, NY (USA))

    1990-02-01

    As part of the Component Fragility Program which was initiated in FY 1985, three additional equipment classes have been evaluated. This report contains the fragility results and discussions on these equipment classes which are switchgear, I and C panels and relays. Both low and medium voltage switchgear assemblies have been considered and a separate fragility estimate for each type is provided. Test data on cabinets from the nuclear instrumentation/neutron monitoring system, plant/process protection system, solid state protective system and engineered safeguards test system comprise the BNL data base for I and C panels (NSSS). Fragility levels have been determined for various failure modes of switchgear and I C panels, and the deterministic results are presented in terms of test response spectra. In addition, the test data have been evaluated for estimating the respective probabilistic fragility levels which are expressed in terms of a median value, an uncertainty coefficient, a randomness coefficient and an HCLPF value. Due to a wide variation of relay design and the fragility level, a generic fragility level cannot be established for relays. 7 refs., 13 figs., 12 tabs.

  8. Molecular-intelligence correlations in young fragile X males with a mild CGG repeat expansion in the FMR1 gene

    Energy Technology Data Exchange (ETDEWEB)

    Steyaert, J. [Central of Clinical Genetics, Maastricht (Netherlands); Borghgraef, M.; Legius, E. [University Hospital Gasthuisberg, Leuven (Belgium)] [and others

    1996-08-09

    Several mechanisms can explain the occurrence of full-mutation fragile X males with an IQ level above -2 SD below mean, also called {open_quotes}high-functioning fragile X males.{close_quotes} Incomplete methylation of the CpG island at the 5{prime} end of the FMR1 gene is one of these mechanisms. The present study describes the physical and behavior phenotypes in 7 fragile X boys with CGG repeat insertions in the FMR1 gene between 600-2,400 base pairs. The degree of methylation at the FMR1-associated CpG island ranges in peripheral blood lymphocytes from 0-95%. Subjects with a low degree of methylation at this site have mild or absent physical characteristics of the fragile X syndrome, while subjects with a high degree of methylation at this site have more severe physical characteristics. In this range of CGG repeat insertion (600-2,400 base pairs), the degree of methylation at the FMR1-associated CpG island is a good predictor of intelligence, while CGG repeat insertion length is not. 13 refs., 1 fig., 1 tab.

  9. Invertible chaotic fragile watermarking for robust image authentication

    Energy Technology Data Exchange (ETDEWEB)

    Sidiropoulos, Panagiotis [Department of Informatics, Aristotle University of Thessaloniki, Box 451, Thessaloniki 54124 (Greece)], E-mail: psid@iti.gr; Nikolaidis, Nikos [Department of Informatics, Aristotle University of Thessaloniki, Box 451, Thessaloniki 54124 (Greece)], E-mail: nikolaid@aiia.csd.auth.gr; Pitas, Ioannis [Department of Informatics, Aristotle University of Thessaloniki, Box 451, Thessaloniki 54124 (Greece)], E-mail: pitas@aiia.csd.auth.gr

    2009-12-15

    Fragile watermarking is a popular method for image authentication. In such schemes, a fragile signal that is sensitive to manipulations is embedded in the image, so that it becomes undetectable after any modification of the original work. Most algorithms focus either on the ability to retrieve the original work after watermark detection (invertibility) or on detecting which image parts have been altered (localization). Furthermore, the majority of fragile watermarking schemes suffer from robustness flaws. We propose a new technique that combines localization and invertibility. Moreover, watermark dependency on the original image and the non-linear watermark embedding procedure guarantees that no malicious attacks will manage to create information leaks.

  10. Fragility and cooperativity concepts in hydrogen-bonded organic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Delpouve, N., E-mail: delpouve.nicolas@gmail.com [AMME-LECAP EA 4528 International Laboratory, University of Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Vuillequez, A.; Saiter, A.; Youssef, B.; Saiter, J.M. [AMME-LECAP EA 4528 International Laboratory, University of Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France)

    2012-09-01

    Molecular dynamics at the glass transition of three lactose/oil glassy systems have been investigated according to the cooperativity and fragility approaches. From Donth's approach, the cooperativity length is estimated by modulated temperature calorimetric measurements. Results reveal that modification of the disaccharide by oil leads to increase the disorder degree in the lactose, the size of the cooperative domains and the fragility index. These particular hydrogen-bonded organic glasses follow the general tendency observed on organic and inorganic polymers: the higher the cooperativity length, the higher the value of the fragility index at T{sub g}.

  11. Subsystem fragility: Seismic Safety Margins Research Program (Phase I)

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, R. P.; Campbell, R. D.; Hardy, G.; Banon, H.

    1981-10-01

    Seismic fragility levels of safety related equipment are developed for use in a seismic oriented Probabilistic Risk Assessment (PRA) being conducted as part of the Seismic Safety Margins Research Program (SSMRP). The Zion Nuclear Power Plant is being utilized as a reference plant and fragility descriptions are developed for specific and generic safety related equipment groups in Zion. Both equipment fragilities and equipment responses are defined in probabilistic terms to be used as input to the SSMRP event tree/fault tree models of the Zion systems. 65 refs., 14 figs., 11 tabs.

  12. Inhibition of p21-activated kinase rescues symptoms of fragile X syndrome in mice.

    Science.gov (United States)

    Hayashi, Mansuo L; Rao, B S Shankaranarayana; Seo, Jin-Soo; Choi, Han-Saem; Dolan, Bridget M; Choi, Se-Young; Chattarji, Sumantra; Tonegawa, Susumu

    2007-07-03

    Fragile X syndrome (FXS), the most commonly inherited form of mental retardation and autism, is caused by transcriptional silencing of the fragile X mental retardation 1 (FMR1) gene and consequent loss of the fragile X mental retardation protein. Despite growing evidence suggesting a role of specific receptors and biochemical pathways in FXS pathogenesis, an effective therapeutic method has not been developed. Here, we report that abnormalities in FMR1 knockout (KO) mice, an animal model of FXS, are ameliorated, at least partially, at both cellular and behavioral levels, by an inhibition of the catalytic activity of p21-activated kinase (PAK), a kinase known to play a critical role in actin polymerization and dendritic spine morphogenesis. Greater spine density and elongated spines in the cortex, morphological synaptic abnormalities commonly observed in FXS, are at least partially restored by postnatal expression of a dominant negative (dn) PAK transgene in the forebrain. Likewise, the deficit in cortical long-term potentiation observed in FMR1 KO mice is fully restored by the dnPAK transgene. Several behavioral abnormalities associated with FMR1 KO mice, including those in locomotor activity, stereotypy, anxiety, and trace fear conditioning are also ameliorated, partially or fully, by the dnPAK transgene. Finally, we demonstrate a direct interaction between PAK and fragile X mental retardation protein in vitro. Overall, our results demonstrate the genetic rescue of phenotypes in a FXS mouse model and suggest that the PAK signaling pathway, including the catalytic activity of PAK, is a novel intervention site for development of an FXS and autism therapy.

  13. Chromosomal instability in meningiomas.

    Science.gov (United States)

    van Tilborg, Angela A G; Al Allak, Bushra; Velthuizen, Sandra C J M; de Vries, Annie; Kros, Johan M; Avezaat, Cees J J; de Klein, Annelies; Beverloo, H Berna; Zwarthoff, Ellen C

    2005-04-01

    Approximately 60% of sporadic meningiomas are caused by inactivation of the NF2 tumor suppressor gene on chromosome 22. No causative gene is known for the remaining 40%. Cytogenetic analysis shows that meningiomas caused by inactivation of the NF2 gene can be divided into tumors that show monosomy 22 as the sole abnormality and tumors with a more complex karyotype. Meningiomas not caused by the NF2 gene usually have a diploid karyotype. Here we report that, besides the clonal chromosomal aberrations, the chromosome numbers in many meningiomas varied from one metaphase spread to the other, a feature that is indicative of chromosomal instability. Unexpectedly and regardless of genotype, a subgroup of tumors was observed with an average number of 44.9 chromosomes and little variation in the number of chromosomes per metaphase spread. In addition, a second subgroup was recognized with a hyperdiploid number of chromosomes (average 48.5) and considerable variation in numbers per metaphase. However, this numerical instability resulted in a clonal karyotype with chromosomal gains and losses in addition to loss of chromosome 22 only in meningiomas caused by inactivation of the NF2 gene. In cultured cells of all tumor groups, bi- and multinucleated cells were seen, as well as anaphase bridges, residual chromatid strings, multiple spindle poles, and unseparated chromatids, suggesting defects in the mitotic apparatus or kinetochore. Thus, we conclude that even a benign and slow-growing tumor like a meningioma displays chromosomal instability.

  14. 脆性X综合征(fragile X syndrome)的分子机理研究%Study of the molecular mechanism of fragile X syndrome

    Institute of Scientific and Technical Information of China (English)

    肖家鹏; 涂知明

    2013-01-01

    脆性X综合征(FraX)是一种常见遗传性智力低下的疾病,在我国人群的发病率仅次于Down氏综合征.细胞学上主要表现为Xq27.3处有一个脆性位点(FRAXA);分子水平上表现为FMR1基因5'端(CGG)n的异常扩增.从X脆性位点克隆到该病的致病基因FMR1,根据FMR1基因的特点,测定湖北人群中CGG重复序列,了解人群中FRA (X)位点(CGG)n的多态性,建立一种简便、快捷的检测方法.我们试图建立FMR-1基因超表达的细胞系和FMR-1基因表达被抑制的细胞系,确定FMRP功能.本研究对该病的筛查和诊断具有重要意义,也为阐明该病的发生机制和基因治疗提供依据.%Fragile X syndrome (FraX) is one of the most common hereditary diseases of mental retardation,its incidence rate just below Down's syndrome.Frax has a fragile sites (FRAXA) in Xq27.3 in cytology,represent a gene FMR1,which is (CGG)n island abnormal amplification.FMR1 gene was cloned from fragile sites (FRAXA),According to characterizaton of FMR1 gene,we measured the repeats of (CGG)n in Hubei human groups,to determine it's polymorphism and set up a simple and quick genetic detection.We are trying to establish a FMR-1 gene overexpressin cell line and a knockout cell line,to test the function of FMRP.This study is meaningful for the screen and diagnosis of Fragile X syndrome (FraX),and useful to understand its mechannism and supply a gene therapy foudation.

  15. The displaced claiming their rights in fragile states

    Directory of Open Access Journals (Sweden)

    Antonia Mulvey

    2013-05-01

    Full Text Available To date, displaced persons in fragile and conflict-affected stateshave had little success in claiming their rights for housing, land andproperty violations. Creative legal thinking and strategic litigation has the potential to change this.

  16. Establishing local government in fragile states: experimental evidence from Afghanistan

    NARCIS (Netherlands)

    T. Jochem; I. Murtazashvili; J. Murtazashvili

    2016-01-01

    International and domestic policy makers often promote elections to establish village government in fragile states. However, two additional options are available in such countries: formalization of self-governing village councils and formalization of community development councils (CDCs). We designe

  17. Financial Reforms and Financial Fragility: A Panel Data Analysis

    Directory of Open Access Journals (Sweden)

    Syed Faizan Iftikhar

    2015-04-01

    Full Text Available This paper explores the relationship between financial reforms, financial liberalization and the quality of banking regulation and supervision for financial fragility by applying a dynamic two-step system generalized method of moments GMM panel estimator technique. The finding of this study is that the financial vulnerability of the banking sector could be affected, not only by bank-specific and macro-specific variables; but also by financial liberalization and banking regulations and supervision policies. The empirical results of this study confirm the evidence that financial reforms and financial liberalization significantly enhance the likelihood of financial fragility while strong banking regulations and supervision have an inverse relationship with financial fragility. The results of this study also explain that the lag value of loan growth and unemployment contribute to enhancing financial fragility while equity to assets ratio, natural log of total assets and share of foreign banks reduce financial vulnerability.

  18. Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes

    DEFF Research Database (Denmark)

    Zhou, Qi; Wang, Jun; Huang, Ling

    2008-01-01

    SNX22 abolished a microRNA target site. Finally, expression analyses revealed complex patterns of expression divergence between neo-Y and neo-X alleles. CONCLUSION: The nascent neo-sex chromosome system of black muntjacs is a valuable model in which to study the evolution of sex chromosomes in mammals......BACKGROUND: The regular mammalian X and Y chromosomes diverged from each other at least 166 to 148 million years ago, leaving few traces of their early evolution, including degeneration of the Y chromosome and evolution of dosage compensation. RESULTS: We studied the intriguing case of black...... muntjac, in which a recent X-autosome fusion and a subsequent large autosomal inversion within just the past 0.5 million years have led to inheritance patterns identical to the traditional X-Y (neo-sex chromosomes). We compared patterns of genome evolution in 35-kilobase noncoding regions and 23 gene...

  19. Analysis of plant meiotic chromosomes by chromosome painting.

    Science.gov (United States)

    Lysak, Martin A; Mandáková, Terezie

    2013-01-01

    Chromosome painting (CP) refers to visualization of large chromosome regions, entire chromosome arms, or entire chromosomes via fluorescence in situ hybridization (FISH). For CP in plants, contigs of chromosome-specific bacterial artificial chromosomes (BAC) from the target species or from a closely related species (comparative chromosome painting, CCP) are typically applied as painting probes. Extended pachytene chromosomes provide the highest resolution of CP in plants. CP enables identification and tracing of particular chromosome regions and/or entire chromosomes throughout all meiotic stages as well as corresponding chromosome territories in premeiotic interphase nuclei. Meiotic pairing and structural chromosome rearrangements (typically inversions and translocations) can be identified by CP. Here, we describe step-by-step protocols of CP and CCP in plant species including chromosome preparation, BAC DNA labeling, and multicolor FISH.

  20. Fragility curves of concrete bridges retrofitted by column jacketing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this study are represented by Iognormal distribution functions with two parameters and developed as a function of PGA. The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA) SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges.The improvement in the fiagility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.

  1. BANKING SYSTEM FRAGILITY: CASE OF THE REPUBLIC OF MOLDOVA

    Directory of Open Access Journals (Sweden)

    Dorina CLICHICI

    2014-04-01

    Full Text Available The paper studied the determinants of Moldovan banking system fragility. It underlines the existing researches into the empirical determinants of banking fragility. The analysis revealed that there are numerous channels through which weaknesses within the macroeconomic conditions and structural characteristics might increase banking system fragility. The main macroeconomic determinants which may have an impact on Moldovan banking system fragility are: excessive domestic liquidity, pro-cyclical character of the banking system, dependence on remittances, financial dollarization. There are also several banking characteristics which play a role for Moldovan banking system fragility: the undermined intermediation function, high level of bad loans, uncertainties in the ownership structure, low presence of foreign strategic investors. The paper employed a quantitative, a qualitative and a comparative analysis using the financial soundness and structural indicators of the Moldovan banking system in order to assess the impact of various determinants on Moldovan banking system fragility. The results reveal a high degree of capitalization and liquidity of Moldovan banking system, factors which contribute and maintain the general stability of the entire financial system.

  2. The fragility of the Brazilian Defense Ministry

    Directory of Open Access Journals (Sweden)

    Jorge Zaverucha

    2006-01-01

    Full Text Available The present article presents different phases that the Brazilian Defense Ministry has passed through, since its inception during Fernando Henrique Cardoso's second presidential term (1999-2002 until the current administration of Luís Inácio Lula da Silva (2003-2006, under its respective ministers of Defense. It has been seen as one of the important stages in the re-constitutionalization of the country, insofar as it establishes the submission of Armed Forces commanders to a civilian minister, and although some analysts have considered that such submission is actually achieved, we point here to the military resistance and insubordination to civil power that are the result of an authoritarian legacy. To the extent that the Ministry of Defense is unable to implement its own policies in which the military would be required to follow civilian guidance, this article concludes with considerations on the civil Defense Ministry's political and institutional fragility vis-a-vis military command. The latter has been able to retain high levels of decision making autonomy in its relationship to the Ministry and its structure.

  3. Interim Stabilisation in Fragile Security Situations

    Directory of Open Access Journals (Sweden)

    Nat J. Colletta

    2012-09-01

    Full Text Available For more than two decades a conventional approach to security promotion has been widely applied by multilateral and bilateral agencies during war-to-peace transitions. Advocates of this approach typically recommend a combination of disarmament, demobilisation and reintegration (DDR and security sector reform (SSR to consolidate peace-making and peace-building processes (Colletta et al 2009, Muggah 2006. Notwithstanding the broad acceptance of such activities – and the theory that underlies them – there is little evidence that such interventions have contributed to any enduring solution to conflict and fragility (Muggah 2009. Indeed, analysts have come to recognise that the political, economic and social pre-conditions for DDR and SSR – including a relatively functional government, a reasonably stable labour market and a minimum level of social trust – are seldom in place. Even when these ambitious pre-requisites have been achieved, it is not clear that they are sufficient for DDR and SSR to take hold. Nevertheless, these orthodoxies persist in security promotion policy and practice.

  4. Seismic fragility of a reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Kurmann, Davide [Axpo Power AG, Baden (Switzerland); Proske, Dirk [Axpo Power AG, Doettingen (Switzerland); Cervenka, Jan [Cervenka Consulting, Prague (Czech Republic)

    2013-05-15

    Structures can be exposed to seismic loading. For structures of major importance, extreme seismic loadings have to be considered. The proof of safety for such loadings requires sophisticated analysis. This paper introduces an analysis method which of course still includes simplifications, but yields to a far more realistic estimation of the seismic load bearing capacity of reinforced concrete structures compared to common methods. It is based on the development of pushover curves and the application of time-histories for the dynamic model to a representative harmonic oscillator. Dynamic parameters of the oscillator, such as modal mass and damping are computed using a soil-structure-interaction analysis. Based on the pushover-curve nonlinear force-deformation-capacities are applied to the oscillator including hysteresis behaviour characteristics. The oscillator is then exposed to time-histories of several earthquakes. Based on this computation the ductility is computed. The ductility can be scaled based upon the scaling of the time-histories. Since both, the uncertainty of the earthquake by using different timehistories and the uncertainty of the structure by using characteristic and mean material values, are considered, the uncertainty of the structure under seismic loading can be explicitly represented by a fragility. (orig.)

  5. Auditory processing in fragile x syndrome.

    Science.gov (United States)

    Rotschafer, Sarah E; Razak, Khaleel A

    2014-01-01

    Fragile X syndrome (FXS) is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle response is seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning, and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable, and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional, and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  6. Cholesterol levels in fragile X syndrome.

    Science.gov (United States)

    Berry-Kravis, Elizabeth; Levin, Rebecca; Shah, Haroon; Mathur, Shaguna; Darnell, Jennifer C; Ouyang, Bichun

    2015-02-01

    Fragile X syndrome (FXS) is associated with intellectual disability and behavioral dysfunction, including anxiety, ADHD symptoms, and autistic features. Although individuals with FXS are largely considered healthy and lifespan is not thought to be reduced, very little is known about the long-term medical health of adults with FXS and no systematically collected information is available on standard laboratory measures from metabolic screens. During the course of follow up of a large cohort of patients with FXS we noted that many patients had low cholesterol and high density lipoprotein (HDL) values and thus initiated a systematic chart review of all cholesterol values present in charts from a clinic cohort of over 500 patients with FXS. Total cholesterol (TC), low density lipoprotein (LDL) and HDL were all significantly reduced in males from the FXS cohort relative to age-adjusted population normative data. This finding has relevance for health monitoring in individuals with FXS, for treatments with cholesterol-lowering agents that have been proposed to target the underlying CNS disorder in FXS based on work in animal models, and for potential biomarker development in FXS.

  7. Auditory Processing in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Sarah E Rotschafer

    2014-02-01

    Full Text Available Fragile X syndrome (FXS is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle is also seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  8. The Brazilian Pampa: A Fragile Biome

    Directory of Open Access Journals (Sweden)

    Valdir Marcos Stefenon

    2009-12-01

    Full Text Available Biodiversity is one of the most fundamental properties of Nature. It underpins the stability of ecosystems, provides vast bioresources for economic use, and has important cultural significance for many people. The Pampa biome, located in the southernmost state of Brazil, Rio Grande do Sul, illustrates the direct and indirect interdependence of humans and biodiversity. The Brazilian Pampa lies within the South Temperate Zone where grasslands scattered with shrubs and trees are the dominant vegetation. The soil, originating from sedimentary rocks, often has an extremely sandy texture that makes them fragile—highly prone to water and wind erosion. Human activities have converted or degraded many areas of this biome. In this review we discuss our state-of-the-art knowledge of the diversity and the major biological features of this regions and the cultural factors that have shaped it. Our aim is to contribute toward a better understanding of the current status of this special biome and to describe how the interaction between human activities and environment affects the region, highlighting the fragility of the Brazilian Pampa.

  9. APP Causes Hyperexcitability in Fragile X Mice

    Science.gov (United States)

    Westmark, Cara J.; Chuang, Shih-Chieh; Hays, Seth A.; Filon, Mikolaj J.; Ray, Brian C.; Westmark, Pamela R.; Gibson, Jay R.; Huber, Kimberly M.; Wong, Robert K. S.

    2016-01-01

    Amyloid-beta protein precursor (APP) and metabolite levels are altered in fragile X syndrome (FXS) patients and in the mouse model of the disorder, Fmr1KO mice. Normalization of APP levels in Fmr1KO mice (Fmr1KO/APPHET mice) rescues many disease phenotypes. Thus, APP is a potential biomarker as well as therapeutic target for FXS. Hyperexcitability is a key phenotype of FXS. Herein, we determine the effects of APP levels on hyperexcitability in Fmr1KO brain slices. Fmr1KO/APPHET slices exhibit complete rescue of UP states in a neocortical hyperexcitability model and reduced duration of ictal discharges in a CA3 hippocampal model. These data demonstrate that APP plays a pivotal role in maintaining an appropriate balance of excitation and inhibition (E/I) in neural circuits. A model is proposed whereby APP acts as a rheostat in a molecular circuit that modulates hyperexcitability through mGluR5 and FMRP. Both over- and under-expression of APP in the context of the Fmr1KO increases seizure propensity suggesting that an APP rheostat maintains appropriate E/I levels but is overloaded by mGluR5-mediated excitation in the absence of FMRP. These findings are discussed in relation to novel treatment approaches to restore APP homeostasis in FXS. PMID:28018172

  10. Sonoran Desert: Fragile Land of Extremes

    Science.gov (United States)

    Produced and Directed by Wessells, Stephen

    2003-01-01

    'Sonoran Desert: Fragile Land of Extremes' shows how biologists with the U.S. Geological Survey work with other scientists in an effort to better understand native plants and animals such as desert tortoises, saguaro cacti, and Gila monsters. Much of the program was shot in and around Saguaro National Park near Tucson, Arizona. Genetic detective work, using DNA, focuses on understanding the lives of tortoises. Studies of saguaros over many decades clarify how these amazing plants reproduce and thrive in the desert. Threats from fire, diseases in tortoises, and a growing human population motivate the scientists. Their work to identify how these organisms live and survive is a crucial step for the sound management of biological resources on public lands. This 28-minute program, USGS Open-File Report 03-305, was shot entirely in high definition video and produced by the USGS Western Ecological Research Center and Southwest Biological Science Center; produced and directed by Stephen Wessells, Western Region Office of Communications.

  11. Oxidative DNA damage in mouse sperm chromosomes: Size matters.

    Science.gov (United States)

    Kocer, Ayhan; Henry-Berger, Joelle; Noblanc, Anais; Champroux, Alexandre; Pogorelcnik, Romain; Guiton, Rachel; Janny, Laurent; Pons-Rejraji, Hanae; Saez, Fabrice; Johnson, Graham D; Krawetz, Stephen A; Alvarez, Juan G; Aitken, R John; Drevet, Joël R

    2015-12-01

    Normal embryo and foetal development as well as the health of the progeny are mostly dependent on gamete nuclear integrity. In the present study, in order to characterize more precisely oxidative DNA damage in mouse sperm we used two mouse models that display high levels of sperm oxidative DNA damage, a common alteration encountered both in in vivo and in vitro reproduction. Immunoprecipitation of oxidized sperm DNA coupled to deep sequencing showed that mouse chromosomes may be largely affected by oxidative alterations. We show that the vulnerability of chromosomes to oxidative attack inversely correlated with their size and was not linked to their GC richness. It was neither correlated with the chromosome content in persisting nucleosomes nor associated with methylated sequences. A strong correlation was found between oxidized sequences and sequences rich in short interspersed repeat elements (SINEs). Chromosome position in the sperm nucleus as revealed by fluorescent in situ hybridization appears to be a confounder. These data map for the first time fragile mouse sperm chromosomal regions when facing oxidative damage that may challenge the repair mechanisms of the oocyte post-fertilization.

  12. Number of X-chromosome genes influences social behavior and vasopressin gene expression in mice.

    Science.gov (United States)

    Cox, Kimberly H; Quinnies, Kayla M; Eschendroeder, Alex; Didrick, Paula M; Eugster, Erica A; Rissman, Emilie F

    2015-01-01

    Sex differences in behavior are widespread and often caused by hormonal differences between the sexes. In addition to hormones, the composition and numbers of the sex chromosomes also affect a variety of sex differences. In humans, X-chromosome genes are implicated in neurobehavioral disorders (i.e. fragile-X, autism). To investigate the role of X-chromosome genes in social behavior, we used a mouse model that has atypical sex chromosome configurations resembling Turner (45, XO) and Klinefelter syndromes (47, XXY). We examined a number of behaviors in juvenile mice. Mice with only one copy of most X-chromosome genes, regardless of gonadal sex, were less social in dyadic interaction and social preference tasks. In the elevated plus maze, mice with one X-chromosome spent less time in the distal ends of the open arms as compared to mice with two copies of X-chromosome genes. Using qRTPCR, we noted that amygdala from female mice with one X-chromosome had higher expression levels of vasopressin (Avp) as compared to mice in the other groups. Finally, in plasma from girls with Turner syndrome we detected reduced vasopressin (AVP) concentrations as compared to control patients. These novel findings link sex chromosome genes with social behavior via concentrations of AVP in brain, adding to our understanding of sex differences in neurobehavioral disorders.

  13. The Precarious Prokaryotic Chromosome

    OpenAIRE

    Kuzminov, Andrei

    2014-01-01

    Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the t...

  14. Mechanisms for chromosome segregation.

    Science.gov (United States)

    Bouet, Jean-Yves; Stouf, Mathieu; Lebailly, Elise; Cornet, François

    2014-12-01

    Bacteria face the problem of segregating their gigantic chromosomes without a segregation period restricted in time and space, as Eukaryotes do. Segregation thus involves multiple activities, general or specific of a chromosome region and differentially controlled. Recent advances show that these various mechanisms conform to a “pair and release” rule, which appears as a general rule in DNA segregation. We describe the latest advances in segregation of bacterial chromosomes with emphasis on the different pair and release mechanisms.

  15. Bacterial chromosome segregation.

    Science.gov (United States)

    Possoz, Christophe; Junier, Ivan; Espeli, Olivier

    2012-01-01

    Dividing cells have mechanisms to ensure that their genomes are faithfully segregated into daughter cells. In bacteria, the description of these mechanisms has been considerably improved in the recent years. This review focuses on the different aspects of bacterial chromosome segregation that can be understood thanks to the studies performed with model organisms: Escherichia coli, Bacillus subtilis, Caulobacter crescentus and Vibrio cholerae. We describe the global positionning of the nucleoid in the cell and the specific localization and dynamics of different chromosomal loci, kinetic and biophysic aspects of chromosome segregation are presented. Finally, a presentation of the key proteins involved in the chromosome segregation is made.

  16. Chromosome oscillations in mitosis

    Science.gov (United States)

    Campas, Otger

    2008-03-01

    Successful cell division necessitates a tight regulation of chromosome movement via the activity of molecular motors. Many of the key players at the origin of the forces generating the motion have been identified, but their spatial and temporal organization remains elusive. In animal cells, chromosomes periodically switch between phases of movement towards and away from the pole. This characteristic oscillatory behaviour cannot be explained by the current models of chromosome positioning and congression. We perform a self-contained theoretical analysis in which the motion of mono-oriented chromosomes results from the competition between the activity of the kinetochore and chromokinesin motors on the chromosome arms. Our analysis, consistent with the available experimental data, proposes that the interplay between the aster-like morphology of the spindle and the collective kinetics of molecular motors is at the origin of chromosome oscillations, positioning and congression. It provides a natural explanation for the so-called chromosome directional instability and for the mechanism by which chromosomes sense their position in space. In addition, we estimate the in vivo velocity of chromokinesins at vanishing load and propose new experiments to assess the mechanism at the origin of chromosome movement in cell division.

  17. Effects of hepatitis B virus infection on human sperm chromosomes

    Institute of Scientific and Technical Information of China (English)

    Jian-Min Huang; Tian-Hua Huang; Huan-Ying Qiu; Xiao-Wu Fang; Tian-Gang Zhuang; Hong-Xi Liu; Yong-Hua Wang; Li-Zhi Deng; Jie-Wen Qiu

    2003-01-01

    AIM: To evaluate the level of sperm chromosome aberrations in male patients with hepatitis B, and to directly detect whether there are HBV DNA integrations in sperm chromosomes of hepatitis B patients.METHODS: Sperm chromosomes of 14 tested subjects (5healthy controls, 9 patients with HBV infection, including 1with acute hepatitis B, 2 with chronic active hepatitis B, 4with chronic persistent hepatitis B, 2 chronic HBsAg carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free golden hamster ova and human spermatozoa, and the frequencies of aberration spermatozoa were compared between subjects of HBV infection and controls. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes.RESULTS: The total frequency of sperm chromosome aberrations in HBV infection group (14.8%, 33/223) was significantly higher than that in the control group (4.3%,5/116). Moreover, the sperm chromosomes in HBV infection patients commonly presented stickiness, clumping, failure to staining, etc, which would affect the analysis of sperm chromosomes. Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis. In 9 (9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots, others presented 2 to 4signals. There was significant difference of fluorescence intensity among the signal spots. The distribution of signal sites among chromosomes was random.CONCLUSION: HBV infection can bring about mutagenic effects on sperm chromosomes. Integrations of viral DNA into sperm chromosomes which are multisites and nonspecific, can further increase the instability of sperm chromosomes. This study suggested that HBV infection can create extensively hereditary effects by alteration genetic constituent and

  18. Oligomerization properties of fragile-X mental-retardation protein (FMRP) and the fragile-X-related proteins FXR1P and FXR2P

    NARCIS (Netherlands)

    F. Tamanini (Filippo); L. van Unen (Leontine); C.E. Bakker (Cathy); N. Sacchi; H. Galjaard (Hans); B.A. Oostra (Ben); A.T. Hoogeveen (Andre)

    1999-01-01

    textabstractThe absence of fragile-X mental-retardation protein (FMRP) results in fragile-X syndrome. Two other fragile-X-related (FXR) proteins have been described, FXR1P and FXR2P, which are both very similar in amino acid sequence to FMRP. Interaction between the thr

  19. Seismic fragility analysis of a nuclear building based on probabilistic seismic hazard assessment and soil-structure interaction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, R.; Ni, S.; Chen, R.; Han, X.M. [CANDU Energy Inc, Mississauga, Ontario (Canada); Mullin, D. [New Brunswick Power, Point Lepreau, New Brunswick (Canada)

    2016-09-15

    Seismic fragility analyses are conducted as part of seismic probabilistic safety assessment (SPSA) for nuclear facilities. Probabilistic seismic hazard assessment (PSHA) has been undertaken for a nuclear power plant in eastern Canada. Uniform Hazard Spectra (UHS), obtained from the PSHA, is characterized by high frequency content which differs from the original plant design basis earthquake spectral shape. Seismic fragility calculations for the service building of a CANDU 6 nuclear power plant suggests that the high frequency effects of the UHS can be mitigated through site response analysis with site specific geological conditions and state-of-the-art soil-structure interaction analysis. In this paper, it is shown that by performing a detailed seismic analysis using the latest technology, the conservatism embedded in the original seismic design can be quantified and the seismic capacity of the building in terms of High Confidence of Low Probability of Failure (HCLPF) can be improved. (author)

  20. Epigenetic modifications in human fragile X pluripotent stem cells; Implications in fragile X syndrome modeling.

    Science.gov (United States)

    Gerhardt, Jeannine

    2017-02-01

    Patients with fragile X syndrome (FXS) exhibit moderate to severe intellectual disabilities. In addition, one-third of FXS patients show characteristics of autism spectrum disorder. FXS is caused by a trinucleotide repeat expansion, which leads to silencing of the fragile X mental retardation (FMR1) gene. The absence of the FMR1 gene product, FMRP, is the reason for the disease symptoms. It has been suggested that repeat instability and transcription of the FMR1 gene occur during early embryonic development, while after cell differentiation repeats become stable and the FMR1 gene is silent. Epigenetic marks, such as DNA methylation, are associated with gene silencing and repeat stability at the FMR1 locus. However, the mechanisms leading to gene silencing and repeat expansion are still ambiguous, because studies at the human genomic locus were limited until now. The FXS pluripotent stem cells, recently derived from FXS adult cells and FXS blastocysts, are new useful tools to examine these mechanisms at the human endogenous FMR1 locus. This review summarizes the epigenetic features and experimental studies of FXS human embryonic and FXS induced pluripotent stem cells, generated so far. This article is part of a Special Issue entitled SI: Exploiting human neurons.

  1. Major chromosomal breakpoint intervals in breast cancer tumors co-localize with differentially methylated regions.

    Directory of Open Access Journals (Sweden)

    Man-Hung Eric eTang

    2012-12-01

    Full Text Available Solid tumors exhibit chromosomal rearrangements resulting in gain or loss of multiple loci (copy number variation and translocations that occasionally result in the creation of novel chimeric genes. In the case of breast cancer, although most individual tumors each have unique CNV landscape the breakpoints, as measured over large datasets, appear to be non-randomly distributed in the genome. Breakpoints show a significant regional concentration at genomic loci spanning perhaps several megabases. The proximal cause of these breakpoint concentrations is a subject of speculation but is, as yet, largely unknown. To shed light on this issue, we have performed a bio-statistical analysis on our previously published data for a set of 119 breast tumors and normal controls, where each sample has both high resolution CNV and methylation data. The method examined the distribution of closeness of breakpoint regions with differentially methylated regions, coupled with additional genomic parameters, such as repeat elements and designated fragile sites in the reference genome. Through this analysis, we have identified a set of 91 regional loci called breakpoint enriched differentially methylated regions (BEDMRs characterized by altered DNA methylation in cancer compared to normal cells that are associated with frequent breakpoint concentrations within a distance of 1Mb. BEDMR loci are further associated with local hypomethylation (66% concentrations of the Alu SINE repeats within 3Mb and tend to occur near a number of cancer related genes such as the protocadherins, AKT1, DUB3, GAB2. BEDMRs seem to deregulate members of the histone gene family and chromatin remodeling factors e.g JMJD1B which might affect the chromatin structure and disrupt coordinate signaling and repair. From this analysis we propose that preference for chromosomal breakpoints is related to genome structure coupled with alterations in DNA methylation and hence chromatin structure associated

  2. 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...... 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...... with women without elevated risk. Spontaneous abortion rate and prematurity rate did not differ from rates expected without amniocentesis. It is concluded that current indications may be characterized as a mixture of evident high risk factors and factors with only a minor influence on risk. Indications...

  3. miR-155 drives telomere fragility in human breast cancer by targeting TRF1.

    Science.gov (United States)

    Dinami, Roberto; Ercolani, Cristiana; Petti, Eleonora; Piazza, Silvano; Ciani, Yari; Sestito, Rosanna; Sacconi, Andrea; Biagioni, Francesca; le Sage, Carlos; Agami, Reuven; Benetti, Roberta; Mottolese, Marcella; Schneider, Claudio; Blandino, Giovanni; Schoeftner, Stefan

    2014-08-01

    Telomeres consist of DNA tandem repeats that recruit the multiprotein complex shelterin to build a chromatin structure that protects chromosome ends. Although cancer formation is linked to alterations in telomere homeostasis, there is little understanding of how shelterin function is limited in cancer cells. Using a small-scale screening approach, we identified miR-155 as a key regulator in breast cancer cell expression of the shelterin component TERF1 (TRF1). miR-155 targeted a conserved sequence motif in the 3'UTR of TRF1, resulting in its translational repression. miR-155 was upregulated commonly in breast cancer specimens, as associated with reduced TRF1 protein expression, metastasis-free survival, and relapse-free survival in estrogen receptor-positive cases. Modulating miR-155 expression in cells altered TRF1 levels and TRF1 abundance at telomeres. Compromising TRF1 expression by elevating miR-155 increased telomere fragility and altered the structure of metaphase chromosomes. In contrast, reducing miR-155 levels improved telomere function and genomic stability. These results implied that miR-155 upregulation antagonizes telomere integrity in breast cancer cells, increasing genomic instability linked to poor clinical outcome in estrogen receptor-positive disease. Our work argued that miRNA-dependent regulation of shelterin function has a clinically significant impact on telomere function, suggesting the existence of "telo-miRNAs" that have an impact on cancer and aging.

  4. Fragility fracture: recent developments in risk assessment.

    Science.gov (United States)

    Aspray, Terry J

    2015-02-01

    More than half of older women who sustain a fragility fracture do not have osteoporosis by World Health Organization (WHO) bone mineral density (BMD) criteria; and, while BMD has been used to assess fracture risk for over 30 years, a range of other skeletal and nonskeletal clinical risk factors (CRFs) for fracture have been recognized. More than 30 assessment tools using CRFs have been developed, some predicting fracture risk and others low BMD alone. Recent systematic reviews have reported that many tools have not been validated against fracture incidence, and that the complexity of tools and the number of CRFs included do not ensure best performance with poor assessment of (internal or comparative) validity. Internationally, FRAX® is the most commonly recommended tool, in addition to QFracture in the UK, The Canadian Association of Radiologists and Osteoporosis Canada (CAROC) tool in Canada and Garvan in Australia. All tools estimate standard 10-year risk of major osteoporotic and 10-year risk of hip fracture: FRAX® is able to estimate fracture risk either with or without BMD, but CAROC and Garvan both require BMD and QFracture does not. The best evidence for the utility of these tools is in case finding but there may be future prospects for the use of 10-year fracture risk as a common currency with reference to the benefits of treatment, whether pharmacological or lifestyle. The use of this metric is important in supporting health economic analyses. However, further calibration studies will be needed to prove that the tools are robust and that their estimates can be used in supporting treatment decisions, independent of BMD.

  5. XYY chromosome anomaly and schizophrenia.

    Science.gov (United States)

    Rajagopalan, M; MacBeth, R; Varma, S L

    1998-02-07

    Sex chromosome anomalies have been associated with psychoses, and most of the evidence is linked to the presence of an additional X chromosome. We report a patient with XYY chromosome anomaly who developed schizophrenia.

  6. Fragility estimates of smart structures with sensor faults

    Science.gov (United States)

    Kim, Yeesock; Bai, Jong-Wha; Albano, Leonard D.

    2013-12-01

    In this paper, the impact of sensor faults within smart structures is investigated using seismic fragility analysis techniques. Seismic fragility analysis is one of the methods used to evaluate the vulnerability of structural systems under a broad range of earthquake events. It would play an important role in estimating seismic losses and in the decision making process based on vibration control performance of the smart structures during seismic events. In this study, a three-story building employing a highly nonlinear hysteretic magnetorheological (MR) damper is analyzed to estimate the seismic fragility of the smart control system. Different levels of sensor damage scenarios for smart structures are considered to provide a better understanding of the expected fragility estimates due to the impact of sensor failures. Probabilistic demand models are constructed with a Bayesian updating approach while the seismic capacity of smart structures is estimated based on the approximate structural performance of semi-actively controlled structures. Peak ground acceleration (PGA) of ground motion is used as a measure of earthquake intensity. Then the fragility curves for the smart structures are developed and compared with those for the semi-active control systems with different levels of sensor damage scenarios. The responses of an uncontrolled structure are used as a baseline. It is shown from the simulations that the proposed methodology is effective in quantifying the impact of sensor faults within smart structures.

  7. Special article: calculus breakability--fragility and durility.

    Science.gov (United States)

    Dretler, S P

    1994-02-01

    Prior to the use of lithotripsy techniques, there was no requirement for a vocabulary to describe the relative breakability of a urinary calculus. With the introduction of lithotripsy, we became aware that calculi of different radiologic appearances or chemical compositions varied in their susceptibility to fragmentation. Because all truly new distinctions require new expressions to characterize them, we had to create a term to express this new distinction, and the term we chose was "stone fragility." Currently, if we see a 1-cm calcium oxalate dihydrate stone, we say it appears fragile ("easily broken," from the Latin frangere, "to break", but if we see a dense brushite or a cystine stone, we can describe it only in terms of fragile; i.e., "not fragile" or, incorrectly, "hard": an antonym for "fragile" does not exist. In the interest of common understanding and more accurate quantitation of stone breakability, a neologism is suggested that has an appropriate Latin root, is easily spoken, sounds authentic, and is useful. It is proposed that, in the interest of accuracy and as a reflection of our greater sophistication regarding stone breakability, we use the Latin root dur (hard, difficult) and a suffix ile (of, like, pertaining to) to create the terms "durile" (adj; pertaining to or capable of being difficult to break) and "durility" (noun; a quality of being difficult to break or fragment).

  8. Chromosomal Abnormalities in Idiopathic Mental Retardation Patients at a Charity Center in Hamadan, Iran

    Directory of Open Access Journals (Sweden)

    Etemadi

    2016-08-01

    Full Text Available Background Chromosomal aberrations are one of the most common causes of mental retardation (MR. Objectives In this study, in order to identify the rate of chromosomal abnormalities in idiopathic MR, 50 MR patients at a charity center in Hamadan, Iran, were investigated. Methods Fifty mentally retarded male patients without specific chromosomal abnormalities (e.g., Down syndrome, Fragile X syndrome, and Klinefelter syndrome were included in the study. Standard cytogenetic techniques and high resolution GTG banding were performed on all the patients. Results All the patients were male, with a mean age of 37.12 years. Skeletal and facial abnormalities were found in 8% and 22% of patients, respectively. All the patients showed a moderate to severe level of mental retardation. None of the patients had numerical chromosome abnormalities. Two out of the 50 patients (4% demonstrated structural chromosomal abnormalities. One patient had a paracentric inversion in chromosome 1, while the other had a pericentric inversion in chromosome 2. Conclusions The presence of structural chromosomal abnormalities (4% in the studied MR patient population emphasizes the importance of cytogenetic investigation for all idiopathic MR patients.

  9. Aging in Fragile X Premutation Carriers.

    Science.gov (United States)

    Lozano, Reymundo; Saito, Naomi; Reed, Dallas; Eldeeb, Marwa; Schneider, Andrea; Hessl, David; Tassone, Flora; Beckett, Laurel; Hagerman, Randi

    2016-10-01

    It is now recognized that FMR1 premutation carriers (PC) are at risk to develop a range of neurological, psychiatric, and immune-mediated disorders during adulthood. There are conflicting findings regarding the incidence of hypertension, hypothyroidism, diabetes, and cancer in these patients that warrant further study. A retrospective controlled study was performed in a convenience sample of 248 controls (130 men, 118 women) and 397 FMR1 PC with and without fragile X-associated tremor ataxia syndrome (FXTAS) (176 men, 221 women); all participants were at least 45 years old (men: mean 62.4, SD 9.5; women: mean 62.8, SD 9.9; p = 0.63). Memory and cognitive assessments (Wechsler Adult Intelligence Scale (WAIS-III), Wechsler Memory Scale (WMS-III)) and molecular testing (CGG repeats and FMR1-mRNA levels) were performed. Additional data included body mass index (BMI), cholesterol levels, blood pressure, hemoglobin A1c (HbA1c) levels, and medical history. A higher percentage of PC subjects self-reported having a diagnosis of hypertension (50.0 vs. 35.0 %, p = 0.006) and thyroid problems (20.4 vs. 10.0 %, p = 0.012) than control subjects. When comparing controls versus PC with FXTAS, the association was higher for diabetes (p = 0.043); however, the effect was not significant after adjusting for demographic predictors. Blood pressure, blood glucose levels, HbA1c, and BMI values were not significantly different between the two groups. The PC with FXTAS group performed consistently lower in neuropsychological testing compared with the PC without FXTAS group, but the differences were very small for all but the WAIS full-scale IQ. Based on these findings, it appears that the risk for hypertension, thyroid problems, and diabetes may be more frequent in PC with FXTAS, which will require verification in future studies.

  10. Touch and Massage for Medically Fragile Infants

    Directory of Open Access Journals (Sweden)

    Karen Livingston

    2009-01-01

    /pain scores of the infants receiving massage. Massage in a tertiary urban academic NICU continues to be an area of needed study. Future studies examining infant health outcomes, such as weight gain, decreased length of hospitalization and caregiver–infant bonding, would provide greater insight into the impact of massage for medically fragile infants.

  11. ASAR15, A cis-acting locus that controls chromosome-wide replication timing and stability of human chromosome 15.

    Directory of Open Access Journals (Sweden)

    Nathan Donley

    2015-01-01

    Full Text Available DNA replication initiates at multiple sites along each mammalian chromosome at different times during each S phase, following a temporal replication program. We have used a Cre/loxP-based strategy to identify cis-acting elements that control this replication-timing program on individual human chromosomes. In this report, we show that rearrangements at a complex locus at chromosome 15q24.3 result in delayed replication and structural instability of human chromosome 15. Characterization of this locus identified long, RNA transcripts that are retained in the nucleus and form a "cloud" on one homolog of chromosome 15. We also found that this locus displays asynchronous replication that is coordinated with other random monoallelic genes on chromosome 15. We have named this locus ASynchronous replication and Autosomal RNA on chromosome 15, or ASAR15. Previously, we found that disruption of the ASAR6 lincRNA gene results in delayed replication, delayed mitotic condensation and structural instability of human chromosome 6. Previous studies in the mouse found that deletion of the Xist gene, from the X chromosome in adult somatic cells, results in a delayed replication and instability phenotype that is indistinguishable from the phenotype caused by disruption of either ASAR6 or ASAR15. In addition, delayed replication and chromosome instability were detected following structural rearrangement of many different human or mouse chromosomes. These observations suggest that all mammalian chromosomes contain similar cis-acting loci. Thus, under this scenario, all mammalian chromosomes contain four distinct types of essential cis-acting elements: origins, telomeres, centromeres and "inactivation/stability centers", all functioning to promote proper replication, segregation and structural stability of each chromosome.

  12. Chromosomal mosaicism goes global

    Directory of Open Access Journals (Sweden)

    Yurov Yuri B

    2008-11-01

    Full Text Available Intercellular differences of chromosomal content in the same individual are defined as chromosomal mosaicism (alias intercellular or somatic genomic variations or, in a number of publications, mosaic aneuploidy. It has long been suggested that this phenomenon poorly contributes both to intercellular (interindividual diversity and to human disease. However, our views have recently become to change due to a series of communications demonstrated a higher incidence of chromosomal mosaicism in diseased individuals (major psychiatric disorders and autoimmune diseases as well as depicted chromosomal mosaicism contribution to genetic diversity, the central nervous system development, and aging. The later has been produced by significant achievements in the field of molecular cytogenetics. Recently, Molecular Cytogenetics has published an article by Maj Hulten and colleagues that has provided evidences for chromosomal mosaicism to underlie formation of germline aneuploidy in human female gametes using trisomy 21 (Down syndrome as a model. Since meiotic aneuploidy is suggested to be the leading genetic cause of human prenatal mortality and postnatal morbidity, these data together with previous findings define chromosomal mosaicism not as a casual finding during cytogenetic analyses but as a more significant biological phenomenon than previously recognized. Finally, the significance of chromosomal mosaicism can be drawn from the fact, that this phenomenon is involved in genetic diversity, normal and abnormal prenatal development, human diseases, aging, and meiotic aneuploidy, the intrinsic cause of which remains, as yet, unknown.

  13. Whole-of-Government Approaches to Fragile States in Africa

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2013-01-01

    For a number of years fragile states have been high on the foreign policy agendas of the USA and the EU. Both actors look upon fragile states with great concern and consider them as security threats. Officially they give priority to ‘whole-of-government approaches’ (wga) when addressing the threats...... a lack of European interests in the fragile states on continent....... from these states. However, there is a gap between the policy declarations and the policies implemented by the two actors. The missing link in the implementation of wga in Africa is explained by two variables: on the one hand, material interests in the continent and, on the other hand, the institutions...

  14. A nonsense mutation in FMR1 causing fragile X syndrome

    DEFF Research Database (Denmark)

    Grønskov, Karen; Brøndum-Nielsen, Karen; Dedic, Alma

    2011-01-01

    Fragile X syndrome is a common cause of inherited intellectual disability. It is caused by lack of the FMR1 gene product FMRP. The most frequent cause is the expansion of a CGG repeat located in the 5'UTR of FMR1. Alleles with 200 or more repeats become hypermethylated and transcriptionally silent....... Only few patients with intragenic point mutations in FMR1 have been reported and, currently, routine analysis of patients referred for fragile X syndrome includes solely analysis for repeat expansion and methylation status. We identified a substitution in exon 2 of FMR1, c.80C>A, causing a nonsense...... mutation p.Ser27X, in a patient with classical clinical symptoms of fragile X syndrome. The mother who carried the mutation in heterozygous form presented with mild intellectual impairment. We conclude that further studies including western blot and DNA sequence analysis of the FMR1 gene should...

  15. CHROMOSOMES OF AMERICAN MARSUPIALS.

    Science.gov (United States)

    BIGGERS, J D; FRITZ, H I; HARE, W C; MCFEELY, R A

    1965-06-18

    Studies of the chromosomes of four American marsupials demonstrated that Caluromys derbianus and Marmosa mexicana have a diploid number of 14 chromosomes, and that Philander opossum and Didelphis marsupialis have a diploid number of 22. The karyotypes of C. derbianus and M. mexicana are similar, whereas those of P. opossum and D. marsupialis are dissimilar. If the 14-chromosome karyotype represents a reduction from a primitive number of 22, these observations suggest that the change has occurred independently in the American and Australasian forms.

  16. Genetics Home Reference: fragile XE syndrome

    Science.gov (United States)

    ... AFF (AF4/FMR2) family of RNA-binding proteins: insights into the molecular pathology of FRAXE intellectual disability. ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...

  17. Erythrocyte osmotic fragility and oxidative stress in experimental hypothyroidism.

    Science.gov (United States)

    Dariyerli, Nuran; Toplan, Selmin; Akyolcu, Mehmet Can; Hatemi, Husrev; Yigit, Gunnur

    2004-10-01

    The present study was planned to explain the relation between erythrocyte osmotic fragility and oxidative stress and antioxidant statue in primary hypothyroid-induced experimental rats. Twenty-four Spraque Dawley type female rats were divided into two, as control (n = 12) and experimental (n = 12), groups weighing between 160 and 200 g. The experimental group animals have received tap water methimazole added standard fodder to block the iodine pumps for 30 d (75 mg/100 g). Control group animals were fed tap water and only standard fodder for the same period. At the end of 30 d blood samples were drawn from the abdominal aorta of the rats under ether anesthesia. T3, T4, and TSH levels were measured and the animals that had relatively lower T3, T4, and higher TSH levels were accepted as hypothyroid group. Hormone levels of the control group were at euthyroid conditions. Osmotic fragility, as a lipid peroxidation indicator malondialdehyde (MDA), antioxidant defense system indicators superoxide dismutase (SOD) and glutathione (GSH) levels were measured in the blood samples. Osmotic fragility test results: There was no statistically significant difference found between maximum osmotic hemolysis limit values of both group. Minimum osmotic hemolysis limit value of hypothyroid group was found to be higher than that of control group values (p proof of increased osmotic fragility of the erythrocytes in hypothyroidism. There is no statistically significant difference found between hypothyroid and control groups in the lipid peroxidation indicator MDA and antioxidant indicators SOD and GSH levels. As a result of our study it may be concluded that hypothyroidism may lead to an increase in osmotic fragility of erythrocytes. But the increase in erythrocyte osmotic fragility does not originate from lipid peroxidation.

  18. Semi-Fragile Watermarking for Copyright Protection and Image Authentication

    Institute of Scientific and Technical Information of China (English)

    HUANG Ji-feng

    2005-01-01

    In this paper, we propose a semi-fragile watermarking technology for copyright protection and image authentication. We transform the image into wavelet domain and group the four adjacent wavelet coefficients. Utilizing the characteristics of the human visual system, we embed a digital signal into the average of the four adjacent wavelet coefficients since the mean has better stability than single wavelet coefficient. This method needn't original image when extracts the watermark. Experimental results show the effectiveness of this method which is robust to common image process and fragile to malicious attack.

  19. Structure and management of tuberculosis control programs in fragile states-Afghanistan, DR Congo, Haiti, Somalia

    NARCIS (Netherlands)

    V. Mauch; D. Weil; A. Munim; F. Boillot; R. Coninx; S. Huseynova; C. Powell; A. Seita; H. Wembanyama; S. van den Hof

    2010-01-01

    Objectives: Health care delivery is particularly problematic in fragile states often connected with increased incidence of communicable diseases, among them tuberculosis. This article draws upon experiences in tuberculosis control in four fragile states from which four lessons learned were derived.

  20. Fragile X-Associated Disorders (FXD): A Handbook for Families, Health Care Providers, Counselors, and Educators

    Science.gov (United States)

    Fragile X-associated Disorders (FXD) A Handbook for Families, Health Care Providers, Counselors, and Educators For Personal Use Only ... contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Section 1: Genetics of Fragile X-Associated Disorders . . . . . . . . . . . . . . . 2 Case Scenario of a Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  1. 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.

  2. [Sex chromosomes and meiosis].

    Science.gov (United States)

    Guichaoua, M-R; Geoffroy-Siraudin, C; Tassistro, V; Ghalamoun-Slaimi, R; Perrin, J; Metzler-Guillemain, C

    2009-01-01

    Sex chromosome behaviour fundamentally differs between male and female meiosis. In oocyte, X chromosomes synapse giving a XX bivalent which is not recognizable in their morphology and behaviour from autosomal bivalents. In human male, X and Y chromosomes differ from one another in their morphology and their genetic content, leading to a limited pairing and preventing genetic recombination, excepted in homologous region PAR1. During pachytene stage of the first meiotic prophase, X and Y chromosomes undergo a progressive condensation and form a transcriptionally silenced peripheral XY body. The condensation of the XY bivalent during pachytene stage led us to describe four pachytene substages and to localize the pachytene checkpoint between substages 2 and 3. We also defined the pachytene index (PI=P1+P2/P1+P2+P3+P4) which is always less than 0.50 in normal meiosis. XY body undergoes decondensation at diplotene stage, but transcriptional inactivation of the two sex chromosomes or Meiotic Sex Chromosome Inactivation (MSCI) persists through to the end of spermatogenesis. Sex chromosome inactivation involves several proteins, some of them were now identified. Two isoforms of the HP1 protein, HP1beta and HP1gamma, are involved in the facultative heterochromatinization of the XY body, but the initiation of this process involves the phosphorylation of the protein H2AX by the kinase ATR whose recruitment depends on BRCA1. Extensive researches on the inactivation of the sex chromosomes during male meiosis will allow to a better understanding of some male infertilities.

  3. Chromosome doubling method

    Science.gov (United States)

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  4. Activation of X Chromosome Inactivation

    NARCIS (Netherlands)

    C.M. Maduro (Cheryl)

    2016-01-01

    markdownabstractIn mammals, males are the heterogametic sex having an X chromosome and a Y chromosome whereas females have two X chromosomes. Despite originating from an ancient homologous autosomal pair, the X and Y chromosome now differ greatly in size and gene content after ~180 MY of evolution.

  5. Vibrio chromosomes share common history

    Directory of Open Access Journals (Sweden)

    Gevers Dirk

    2010-05-01

    Full Text Available Abstract Background While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation. Results Single copy genes from each chromosome (142 genes from chromosome I and 42 genes from chromosome II were identified from 19 sequenced Vibrionales genomes and their phylogenetic comparison suggests consistent phylogenies for each chromosome. Additionally, study of the gene organization and phylogeny of the respective origins of replication confirmed the shared history. Conclusions Thus, while elements within the chromosomes may have experienced significant genetic mobility, the backbones share a common history. This allows conclusions based on multilocus sequence analysis (MLSA for one chromosome to be applied equally to both chromosomes.

  6. Between Development and Security: The European Union, Governance and Fragile States

    NARCIS (Netherlands)

    W. Hout (Wil)

    2009-01-01

    textabstractOver the past five to seven years, most international aid donors have started to pay attention to so-called ‘fragile states’. Generally, the interest in state fragility was spurred by security considerations in the wake of the terrorist attacks of ‘9/11’. Fragile states came to be seen a

  7. Differential Impact of the "FMR1" Gene on Visual Processing in Fragile X Syndrome

    Science.gov (United States)

    Kogan, Cary S.; Boutet, Isabelle; Cornish, Kim; Zangenehpour, Shahin; Mullen, Kathy T.; Holden, Jeanette J. A.; Kaloustian, Vazken M. Der; Andermann, Eva; Chaudhuri, Avi

    2004-01-01

    Fragile X syndrome (FXS) is the most common form of heritable mental retardation, affecting (~ around) 1 in 4000 males. The syndrome arises from expansion of a trinucleotide repeat in the 5'-untranslated region of the fragile X mental retardation 1 ("FMR1") gene, leading to methylation of the promoter sequence and lack of the fragile X mental…

  8. Strategy for reliable prenatal detection of normal male carriers of the fragile X syndrome

    NARCIS (Netherlands)

    D.J.J. Halley (Dicky); A.M.W. van den Ouweland (Ans); W.H. Deelen (Wouter); C.S. Verma (Chandra); B.A. Oostra (Ben)

    1994-01-01

    textabstractPrenatal diagnosis of fragile X syndrome identifying full mutations has been described. Here we report on a case of a prenatal test concerning a normal male carrier of the fragile X syndrome. Southern blot analysis of the fragile X gene resulted in the identification of a premutation in

  9. Theory of Mind Deficits in Children with Fragile X Syndrome

    Science.gov (United States)

    Cornish, K.; Burack, J. A.; Rahman, A.; Munir, F.; Russo, N.; Grant, C.

    2005-01-01

    Given the consistent findings of theory of mind deficits in children with autism, it would be extremely beneficial to examine the profile of theory of mind abilities in other clinical groups such as fragile X syndrome (FXS) and Down syndrome (DS). The aim of the present study was to assess whether boys with FXS are impaired in simple social…

  10. Development of hazard-compatible building fragility and vulnerability models

    Science.gov (United States)

    Karaca, E.; Luco, N.

    2008-01-01

    We present a methodology for transforming the structural and non-structural fragility functions in HAZUS into a format that is compatible with conventional seismic hazard analysis information. The methodology makes use of the building capacity (or pushover) curves and related building parameters provided in HAZUS. Instead of the capacity spectrum method applied in HAZUS, building response is estimated by inelastic response history analysis of corresponding single-degree-of-freedom systems under a large number of earthquake records. Statistics of the building response are used with the damage state definitions from HAZUS to derive fragility models conditioned on spectral acceleration values. Using the developed fragility models for structural and nonstructural building components, with corresponding damage state loss ratios from HAZUS, we also derive building vulnerability models relating spectral acceleration to repair costs. Whereas in HAZUS the structural and nonstructural damage states are treated as if they are independent, our vulnerability models are derived assuming "complete" nonstructural damage whenever the structural damage state is complete. We show the effects of considering this dependence on the final vulnerability models. The use of spectral acceleration (at selected vibration periods) as the ground motion intensity parameter, coupled with the careful treatment of uncertainty, makes the new fragility and vulnerability models compatible with conventional seismic hazard curves and hence useful for extensions to probabilistic damage and loss assessment.

  11. Synaptic vesicle dynamic changes in a model of fragile X

    NARCIS (Netherlands)

    A.C. Broek (Jantine); Z. Lin (Zhanmin); H.M. de Gruiter (H. Martijn); H. van 't Spijker (Heleen); E.D. Haasdijk (Elize); D. Cox (David); S. Ozcan (Sureyya); W.A. van Cappellen (Gert); A.B. Houtsmuller (Adriaan); R. Willemsen (Rob); C.I. de Zeeuw (Chris); S. Bahn (Sabine)

    2016-01-01

    markdownabstract__Background:__ Fragile X syndrome (FXS) is a single-gene disorder that is the most common heritable cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorders (ASD). FXS is caused by an expansion of trinucleotide repeats in the promoter regio

  12. Noninvasive test for fragile X syndrome, using hair root analysis

    NARCIS (Netherlands)

    R. Willemsen (Rob); B. Anar (Burcu); Y. de Diego Otero (Yolanda); B.B.A. de Vries (Bert); Y. Hilhorst-Hofstee (Yvonne); A. Smits; E. van Looveren; P.J. Willems (Patrick); H. Galjaard (Hans); B.A. Oostra (Ben)

    1999-01-01

    textabstractIdentification of the FMR1 gene and the repeat-amplification mechanism causing fragile X syndrome led to development of reliable DNA-based diagnostic methods, including Southern blot hybridization and PCR. Both methods are performed on DNA isolated from peri

  13. Social Cognition in Adolescent Girls with Fragile X Syndrome

    Science.gov (United States)

    Turkstra, Lyn S.; Abbeduto, Leonard; Meulenbroek, Peter

    2014-01-01

    This study aimed to characterize social cognition, executive functions (EFs), and everyday social functioning in adolescent girls with fragile X syndrome, and identify relationships among these variables. Participants were 20 girls with FXS and 20 age-matched typically developing peers. Results showed significant between-groups differences in…

  14. Mothers' Economic Conditions and Sources of Support in Fragile Families

    Science.gov (United States)

    Kalil, Ariel; Ryan, Rebecca M.

    2010-01-01

    Rising rates of nonmarital childbirth in the United States have resulted in a new family type, the fragile family. Such families, which include cohabiting couples as well as single mothers, experience significantly higher rates of poverty and material hardship than their married counterparts. Ariel Kalil and Rebecca Ryan summarize the economic…

  15. Mechanisms of diabetes mellitus-induced bone fragility

    DEFF Research Database (Denmark)

    Napoli, Nicola; Chandran, Manju; Pierroz, Dominique D;

    2017-01-01

    The risk of fragility fractures is increased in patients with either type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM). Although BMD is decreased in T1DM, BMD in T2DM is often normal or even slightly elevated compared with an age-matched control population. However, in both T1DM ...

  16. Phonological Awareness and Reading in Boys with Fragile X Syndrome

    Science.gov (United States)

    Adlof, Suzanne M.; Klusek, Jessica; Shinkareva, Svetlana V.; Robinson, Marissa L.; Roberts, Jane E.

    2015-01-01

    Background: Reading delays are well documented in children with fragile X syndrome (FXS), but few studies have examined linguistic precursors of reading in this population. This study examined the longitudinal development of phonological awareness and its relationship with basic reading in boys with FXS. Individual differences in genetic,…

  17. Open-Label Memantine in Fragile X Syndrome

    Science.gov (United States)

    Erickson, Craig A.; Mullett, Jennifer E.; McDougle, Christopher J.

    2009-01-01

    Glutamatergic dysfunction is implicated in the pathophysiology of fragile X syndrome (FXS). The purpose of this pilot study was to examine the effectiveness and tolerability of memantine for a number of target symptoms associated with FXS. Medical records describing open-label treatment with memantine in 6 patients with FXS and a comorbid…

  18. What Are the Symptoms of Fragile X Syndrome?

    Science.gov (United States)

    ... as tone of voice or specific types of body language. Girls usually do not have severe problems with speech or language. Some children with Fragile X begin talking later than ... feels on their bodies. These sensory issues might cause them to act ...

  19. Social Approach and Emotion Recognition in Fragile X Syndrome

    Science.gov (United States)

    Williams, Tracey A.; Porter, Melanie A.; Langdon, Robyn

    2014-01-01

    Evidence is emerging that individuals with Fragile X syndrome (FXS) display emotion recognition deficits, which may contribute to their significant social difficulties. The current study investigated the emotion recognition abilities, and social approachability judgments, of FXS individuals when processing emotional stimuli. Relative to…

  20. Arousal Modulation in Females with Fragile X or Turner Syndrome

    Science.gov (United States)

    Roberts, Jane; Mazzocco, Michele M. M.; Murphy, Melissa M.; Hoehn-Saric, Rudolf

    2008-01-01

    The present study was carried out to examine physiological arousal modulation (heart activity and skin conductance), across baseline and cognitive tasks, in females with fragile X or Turner syndrome and a comparison group of females with neither syndrome. Relative to the comparison group, for whom a greater increase in skin conductance was…

  1. Autism Profiles of Males With Fragile X Syndrome

    Science.gov (United States)

    Harris, Susan W.; Hessl, David; Goodlin-Jones, Beth; Ferranti, Jessica; Bacalman, Susan; Barbato, Ingrid; Tassone, Flora; Hagerman, Paul J.; Herman, Kristin; Hagerman, Randi J.

    2008-01-01

    Autism, which is common in individuals with fragile X syndrome, is often difficult to diagnose. We compared the diagnostic classifications of two measures for autism diagnosis, the ADOS and the ADI-R, in addition to the DSM-IV-TR in 63 males with this syndrome. Overall, 30% of the subjects met criteria for autistic disorder and 30% met criteria…

  2. Component Fragility Research Program: Phase 1 component prioritization

    Energy Technology Data Exchange (ETDEWEB)

    Holman, G.S.; Chou, C.K.

    1987-06-01

    Current probabilistic risk assessment (PRA) methods for nuclear power plants utilize seismic ''fragilities'' - probabilities of failure conditioned on the severity of seismic input motion - that are based largely on limited test data and on engineering judgment. Under the NRC Component Fragility Research Program (CFRP), the Lawrence Livermore National Laboratory (LLNL) has developed and demonstrated procedures for using test data to derive probabilistic fragility descriptions for mechanical and electrical components. As part of its CFRP activities, LLNL systematically identified and categorized components influencing plant safety in order to identify ''candidate'' components for future NRC testing. Plant systems relevant to safety were first identified; within each system components were then ranked according to their importance to overall system function and their anticipated seismic capacity. Highest priority for future testing was assigned to those ''very important'' components having ''low'' seismic capacity. This report describes the LLNL prioritization effort, which also included application of ''high-level'' qualification data as an alternate means of developing probabilistic fragility descriptions for PRA applications.

  3. Infant Development in Fragile X Syndrome: Cross-Syndrome Comparisons

    Science.gov (United States)

    Roberts, Jane E.; McCary, Lindsay M.; Shinkareva, Svetlana V.; Bailey, Donald B., Jr.

    2016-01-01

    This study examined the developmental profile of male infants with fragile X syndrome (FXS) and its divergence from typical development and development of infants at high risk for autism associated with familial recurrence (ASIBs). Participants included 174 boys ranging in age from 5 to 28 months. Cross-sectional profiles on the Mullen Scales of…

  4. White Religious Educators Resisting White Fragility: Lessons from Mystics

    Science.gov (United States)

    Hess, Mary E.

    2017-01-01

    Decades of work in dismantling racism have not yielded the kind of results for which religious educators have hoped. One primary reason has been what scholars term "white fragility," a symptom of the structural racism which confers systemic privilege upon White people. Lessons learned from Christian mystics point to powerful ways to…

  5. Fiscal deficits, financial fragility, and the effectiveness of government policies

    NARCIS (Netherlands)

    Kirchner, M.; van Wijnbergen, S.

    2016-01-01

    Recent developments in the euro area highlighted the interactions between fiscal policy, sovereign debt and financial fragility. We introduce asset choice and sovereign debt holdings in banks’ portfolios in an otherwise standard macroeconomic model with financial frictions, to emphasize a new crowdi

  6. The False Coin Problem, Mathematical Induction and Knowledge Fragility.

    Science.gov (United States)

    Movshovitz-Hadar, Nitsa

    1993-01-01

    Shows fragility of knowledge in connection with a false application of mathematical induction, as observed in a problem-solving course for prospective teachers. The attempt to explain the observations is based upon an analysis of the logic underlying proof by mathematical induction and a concept formation theory. (MKR)

  7. Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards

    Science.gov (United States)

    Ham, H. J.; Lee, S.; Choi, S. H.; Yun, W. S.

    2015-12-01

    Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards Hee Jung Ham1, Seung-Hun Choi1, Woo-Seok Yun1, Sungsu Lee2 1Department of Architectural Engineering, Kangwon National University, Korea 2Division of Civil Engineering, Chungbuk National University, Korea ABSTRACT In this study, fragility functions are developed to estimate expected volcanic ash damages of the agricultural sector in Korea. The fragility functions are derived from two approaches: 1) empirical approach based on field observations of impacts to agriculture from the 2006 eruption of Merapi volcano in Indonesia and 2) the FOSM (first-order second-moment) analytical approach based on distribution and thickness of volcanic ash observed from the 1980 eruption of Mt. Saint Helens and agricultural facility specifications in Korea. Fragility function to each agricultural commodity class is presented by a cumulative distribution function of the generalized extreme value distribution. Different functions are developed to estimate production losses from outdoor and greenhouse farming. Seasonal climate influences vulnerability of each agricultural crop and is found to be a crucial component in determining fragility of agricultural commodities to an ash fall. In the study, the seasonality coefficient is established as a multiplier of fragility function to consider the seasonal vulnerability. Yields of the different agricultural commodities are obtained from Korean Statistical Information Service to create a baseline for future agricultural volcanic loss estimation. Numerically simulated examples of scenario ash fall events at Mt. Baekdu volcano are utilized to illustrate the application of the developed fragility functions. Acknowledgements This research was supported by a grant 'Development of Advanced Volcanic Disaster Response System considering Potential Volcanic Risk around Korea' [MPSS-NH-2015-81] from the Natural Hazard Mitigation Research Group, Ministry of Public Safety and Security of

  8. Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome

    Institute of Scientific and Technical Information of China (English)

    Anurag Mitra; Rima Dada; Rajeev Kumar; Narmada Prasad Gupta; Kiran Kucheria; Satish Kumar Gupta

    2006-01-01

    Aim: To study the occurrence of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome (KFS). Methods: Blood and semen samples were collected from azoospermic patients with KFS (n = 14) and a control group of men of proven fertility (n = 13). Semen analysis was done according to World Health Organization (WHO) guidelines. Blood samples were processed for karyotyping, fluorescent in situ hybridization (FISH) and measurement of plasma follicle stimulating hormone (FSH) by radioimmunoassay. To determine Y chromosome microdeletions, polymerase chain reaction (PCR) of 16 sequence tagged sites (STS) and three genes (DFFRY, XKRY and RBM1 Y) was performed on isolated genomic DNA. Testicular fine needle aspiration cytology (FNAC) was done in selected cases. Results: Y chromosome microdeletions spanning the azoospermia factor (AZF)a and AZFb loci were found in four of the 14 azoospermic patients with KFS. Karyotype and FISH analysis revealed that, of the four cases showing Y chromosome microdeletion, three cases had a 47,XXY/46,XY chromosomal pattern and one case had a 46,XY/47,XXY/48,XXXY/48,XXYY chromosomal pattern. The testicular FNAC of one sample with Y chromosome microdeletion revealed Sertoli cell-only type of morphology. However, no Y chromosome microdeletions were observed in any of the 13 fertile men. All patients with KFS had elevated plasma FSH levels. Conclusion:Patients with KFS may harbor Y chromosome microdeletions and screening for these should be a part of their diagnostic work-up, particularly in those considering assisted reproductive techniques.

  9. Clinical assessment tools identify functional deficits in fragility fracture patients

    Directory of Open Access Journals (Sweden)

    Ames TD

    2016-05-01

    Full Text Available Tyler D Ames,1 Corinne E Wee,1 Khoi M Le,1 Tiffany L Wang,1 Julie Y Bishop,2 Laura S Phieffer,2 Carmen E Quatman2 1The Ohio State University College of Medicine, 2Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA Purpose: To identify inexpensive, noninvasive, portable, clinical assessment tools that can be used to assess functional performance measures that may put older patients at risk for falls such as balance, handgrip strength, and lumbopelvic control.Patients and methods: Twenty fragility fracture patients and 21 healthy control subjects were evaluated using clinical assessment tools (Nintendo Wii Balance Board [WBB], a handheld dynamometer, and an application for the Apple iPod Touch, the Level Belt that measure functional performance during activity of daily living tasks. The main outcome measurements were balance (WBB, handgrip strength (handheld dynamometer, and lumbopelvic control (iPod Touch Level Belt, which were compared between fragility fracture patients and healthy controls.Results: Fragility fracture patients had lower scores on the vertical component of the WBB Torso Twist task (P=0.042 and greater medial–lateral lumbopelvic sway during a 40 m walk (P=0.026 when compared to healthy controls. Unexpectedly, the fracture patients had significantly higher scores on the left leg (P=0.020 and total components (P=0.010 of the WBB Single Leg Stand task as well as less faults during the left Single Leg Stand task (P=0.003.Conclusion: The clinical assessment tools utilized in this study are relatively inexpensive and portable tools of performance measures capable of detecting differences in postural sway between fragility fracture patients and controls. Keywords: fall risk, geriatric fracture, Nintendo Wii Balance Board, Level Belt, fragility fracture

  10. Vitamin E effect on osmotic fragility in β thalassemia major

    Directory of Open Access Journals (Sweden)

    Agus Fitrianto

    2014-09-01

    Full Text Available Background Blood transfusion remains the main therapy for anemia in β thalassemia major patients. However, frequent transfusions can cause oxidative stress in response to iron overload. Vitamin E is considered to be the best lipid-soluble exogenous antioxidant in humans. It can protect phospholipid membrane from peroxidation. Erythrocyte osmotic fragility is a useful test to assess for the improvement of red blood cells in thalassemia patients after vitamin E supplementation. Objective To investigate the effect of vitamin E for improving erythrocyte osmotic fragility in β- thalassemia major and for decreasing the need for frequent transfusions. Methods This was a double blind placebo controlled randomized clinical trial on children aged 2-14 years with thalassemia major who received frequent blood transfusions. Fifty subjects were divided into 2 groups: group I with vitamin E supplementation and group II with placebo, as a control group, for a period of 1 month. Pre- and post-treatment data on erythrocyte osmotic fragility and hemoglobin level were analyzed with non-paired T-test. Results Improved erythrocyte osmotic fragility was found: in group I, pre-treatment 31.59 (SD 6.342% to post-treatment 38.08 (SD 7.165%, compared to the control group pre-treatment 34.40 (SD 6.985% to post-treatment 29.26 (SD 9.011% (P=0.0001. Comparison of the mean delta Hb level in group I was 0.94 (SD 0.605 gr% and that of group II was - 0.23 (SD 1.199 gr% (P= 0.0001. Conclusion Vitamin E supplementation improves erythrocyte fragility and Hb level in β-thalassemia major pediatric patients. [Paediatr Indones. 2014;54:280-3.].

  11. "Chromosome": a knowledge-based system for the chromosome classification.

    Science.gov (United States)

    Ramstein, G; Bernadet, M

    1993-01-01

    Chromosome, a knowledge-based analysis system has been designed for the classification of human chromosomes. Its aim is to perform an optimal classification by driving a tool box containing the procedures of image processing, pattern recognition and classification. This paper presents the general architecture of Chromosome, based on a multiagent system generator. The image processing tool box is described from the met aphasic enhancement to the fine classification. Emphasis is then put on the knowledge base intended for the chromosome recognition. The global classification process is also presented, showing how Chromosome proceeds to classify a given chromosome. Finally, we discuss further extensions of the system for the karyotype building.

  12. Human keratin diseases: hereditary fragility of specific epithelial tissues.

    Science.gov (United States)

    Corden, L D; McLean, W H

    1996-12-01

    Keratins are heteropolymeric proteins which form the intermediate filament cytoskeleton in epithelial cells. Since 1991, mutations in several keratin genes have been found to cause a variety of human diseases affecting the epidermis and other epithelial structures. Epidermolysis bullosa simplex (EBS) was the first mechanobullous disease for which the underlying genetic lesion was found, with mutations in both the K5 and K14 genes rendering basal epidermal keratinocytes less resilient to trauma, resulting in skin fragility. The site of mutation in the keratin protein correlates with phenotypic severity in this disorder. Since mutations were identified in the basal cell keratins, the total number of keratin genes associated with diseases has risen to eleven. The rod domains of suprabasal keratins K1 and K10 are mutated in bullous congenital ichthyosiform erythroderma (BCIE; also called epidermolytic hyperkeratosis, EH) and mosaicism for K1/K10 mutations results in a nevoid distribution of EH. An unusual mutation in the VI domain of K1 has also been found to cause diffuse non-epidermolytic palmoplantar keratoderma (DNEPPK). Mutations in palmoplantar specific keratin K9 cause epidermolytic palmoplantar keratoderma (EPPK) and mutations in the late differentiation suprabasal keratin K2e cause ichthyosis bullosa of Siemens (IBS). In the last year or so, mutations were discovered in differentiation specific keratins K6a and K16 causing pachyonychia congenita type 1 and K17 mutations occur in pachyonychia congenita type 2. K16 and K17 mutations have also been reported to produce phenotypes with little or no nail changes: K16 mutations can present as focal non-epidermolytic palmoplantar keratoderma (NEPPK) and K17 mutations can result in a phenotype resembling steatocystoma multiplex. Recently, mutation of mucosal keratin pair K4 and K13 has been shown to underlie white sponge nevus (WSN). This year, the first mutations in a keratin-associated protein, plectin, were shown to

  13. Fragile X premutation is a significant risk factor for premature ovarian failure: the International Collaborative POF in Fragile X study--preliminary data.

    Science.gov (United States)

    Allingham-Hawkins, D J; Babul-Hirji, R; Chitayat, D; Holden, J J; Yang, K T; Lee, C; Hudson, R; Gorwill, H; Nolin, S L; Glicksman, A; Jenkins, E C; Brown, W T; Howard-Peebles, P N; Becchi, C; Cummings, E; Fallon, L; Seitz, S; Black, S H; Vianna-Morgante, A M; Costa, S S; Otto, P A; Mingroni-Netto, R C; Murray, A; Webb, J; Vieri, F

    1999-04-01

    The preliminary results of an international collaborative study examining premature menopause in fragile X carriers are presented. A total of 760 women from fragile X families was surveyed about their fragile X carrier status and their menstrual and reproductive histories. Among the subjects, 395 carried a premutation, 128 carried a full mutation, and 237 were noncarriers. Sixty-three (16%) of the premutation carriers had experienced menopause prior to the age of 40 compared with none of the full mutation carriers and one (0.4%) of the controls. Based on these preliminary data, there is a significant association between fragile X premutation carrier status and premature menopause.

  14. Hypermethylated Chromosome Regions in Nine Fish Species with Heteromorphic Sex Chromosomes.

    Science.gov (United States)

    Schmid, Michael; Steinlein, Claus; Yano, Cassia F; Cioffi, Marcelo B

    2015-01-01

    Sites and amounts of 5-methylcytosine (5-MeC)-rich chromosome regions were detected in the karyotypes of 9 Brazilian species of Characiformes fishes by indirect immunofluorescence using a monoclonal anti-5-MeC antibody. These species, belonging to the genera Leporinus, Triportheus and Hoplias, are characterized by highly differentiated and heteromorphic ZW and XY sex chromosomes. In all species, the hypermethylated regions are confined to constitutive heterochromatin. The number and chromosome locations of hypermethylated heterochromatic regions in the karyotypes are constant and species-specific. Generally, heterochromatic regions that are darkly stained by the C-banding technique are distinctly hypermethylated, but several of the brightly fluorescing hypermethylated regions merely exhibit moderate or faint C-banding. The ZW and XY sex chromosomes of all 9 analyzed species also show species-specific heterochromatin hypermethylation patterns. The analysis of 5-MeC-rich chromosome regions contributes valuable data for comparative cytogenetics of closely related species and highlights the dynamic process of differentiation operating in the repetitive DNA fraction of sex chromosomes.

  15. The psychiatric presentation of fragile x: evolution of the diagnosis and treatment of the psychiatric comorbidities of fragile X syndrome.

    Science.gov (United States)

    Tranfaglia, Michael R

    2011-01-01

    Fragile X syndrome (FXS) is the leading inherited cause of mental retardation and autism spectrum disorders worldwide. It presents with a distinct behavioral phenotype which overlaps significantly with that of autism. Unlike autism and most common psychiatric disorders, the neurobiology of fragile X is relatively well understood. Lack of the fragile X mental retardation protein causes dysregulation of synaptically driven protein synthesis, which in turn causes global disruption of synaptic plasticity. Thus, FXS can be considered a disorder of synaptic plasticity, and a developmental disorder in the purest sense: mutation of the FMR1 (fragile X mental retardation 1) gene results in abnormal synaptic development in response to experience. Accumulation of this abnormal synaptic development, over time, leads to a characteristic and surprisingly consistent behavioral phenotype of attention deficit, hyperactivity, impulsivity, multiple anxiety symptoms, repetitive/perseverative/stereotypic behaviors, unstable affect, aggression, and self-injurious behavior. Many features of the behavioral and psychiatric phenotype of FXS follow a developmental course, waxing and waning over the life span. In most cases, symptoms present as a mixed clinical picture, not fitting established diagnostic categories. There have been many clinical trials in fragile X subjects, but no placebo-controlled trials of adequate size or methodology utilizing the most commonly prescribed psychiatric medications. However, large and well-designed trials of investigational agents which target the underlying pathology of FXS have recently been completed or are under way. While the literature offers little guidance to the clinician treating patients with FXS today, potentially disease-modifying treatments may be available in the near future.

  16. Characterisation of the chromosome fusions in Oreochromis karongae.

    Science.gov (United States)

    Mota-Velasco, Jose C; Ferreira, Irani Alves; Cioffi, Marcelo B; Ocalewicz, Konrad; Campos-Ramos, Rafael; Shirak, Andrey; Lee, Bo-Young; Martins, Cesar; Penman, David J

    2010-07-01

    Oreochromis karongae, one of the "chambo" tilapia species from Lake Malawi, has a karyotype of 2n = 38, making it one of the few species investigated to differ from the typical tilapia karyotype (2n = 44). The O. karongae karyotype consists of one large subtelocentric pair of chromosomes, four medium-sized pairs (three subtelocentric and one submetacentric) and 14 small pairs. The five largest pairs could be distinguished from each other on the basis of size, morphology and a series of fluorescence in situ hybridisation (FISH) probes. The largest pair is easily distinguished on the basis of size and a chromosome 1 (linkage group 3) bacterial artificial chromosome (BAC) FISH probe from Oreochromis niloticus. BAC clones from O. niloticus chromosome 2 (linkage group 7) hybridised to one of the medium-sized subtelocentric chromosome pairs (no. 5) of O. karongae, distinguishing the ancestral medium-sized pair from the three other medium-sized chromosome pairs (nos. 2, 3 and 4) that appear to have resulted from fusions. SATA repetitive DNA hybridised to the centromeres of all 19 chromosome pairs and also revealed the locations of the relic centromeres in the three fused pairs. Telomeric (TTAGGG)(n) repeats were identified in the telomeres of all chromosomes, and an interstitial telomeric site (ITS) was identified in three chromosomal pairs (no. 2, 3 and 4). Additionally, two ITS sites were identified in the largest chromosome pair (pair 1), confirming the origin of this chromosome from three ancestral chromosomes. SATA and ITS sites allowed the orientation of the fusions in pairs 2, 3 and 4, which all appear to have been in different orientations (q-q, p-q and p-p, respectively). One of these fusions (O. karongae chromosome pair no. 2) involves a small chromosome (equivalent to linkage group 1), which in O. niloticus carries the main sex-determining gene. 4',6-Diamidino-2-phenyloindole staining of the synaptonemal complex in male O. karongae revealed the presumptive

  17. Chromosome numbers in Bromeliaceae

    Directory of Open Access Journals (Sweden)

    Cotias-de-Oliveira Ana Lúcia Pires

    2000-01-01

    Full Text Available The present study reports chromosome numbers of 17 species of Bromeliaceae, belonging to the genera Encholirium, Bromelia, Orthophytum, Hohenbergia, Billbergia, Neoglaziovia, Aechmea, Cryptanthus and Ananas. Most species present 2n = 50, however, Bromelia laciniosa, Orthophytum burle-marxii and O. maracasense are polyploids with 2n = 150, 2n = 100 and 2n = 150, respectively, while for Cryptanthus bahianus, 2n = 34 + 1-4B. B chromosomes were observed in Bromelia plumieri and Hohenbergia aff. utriculosa. The chromosome number of all species was determined for the first time, except for Billbergia chlorosticta and Cryptanthus bahianus. Our data supports the hypothesis of a basic number of x = 25 for the Bromeliaceae family and decreasing aneuploidy in the genus Cryptanthus.

  18. Those amazing dinoflagellate chromosomes

    Institute of Scientific and Technical Information of China (English)

    PETER J RIZZO

    2003-01-01

    Dinoflagellates are a very large and diverse group of eukaryotic algae that play a major role in aquatic food webs of both fresh water and marine habitats. Moreover, the toxic members of this group pose a health threat in the form of red tides. Finally, dinoflagellates are of great evolutionary importance,because of their taxonomic position, and their unusual chromosome structure and composition. While the cytoplasm of dinoflagellates is typically eukaryotic, the nucleus is unique when compared to the nucleus of other eukaryotes. More specifically, while the chromosomes of all other eukaryotes contain histones,dinoflagellate chromosomes lack histones completely. There are no known exceptions to this observation: all dinoflagellates lack histones, and all other eukaryotes contain histones. Nevertheless, dinoflagellates remain a relatively unstudied group of eukaryotes.

  19. Differentiation of the XY sex chromosomes in the fish Hoplias malabaricus (Characiformes, Erythrinidae): unusual accumulation of repetitive sequences on the X chromosome.

    Science.gov (United States)

    Cioffi, M B; Martins, C; Vicari, M R; Rebordinos, L; Bertollo, L A C

    2010-01-01

    The wolf fish Hoplias malabaricus (Erythrinidae) presents a high karyotypic diversity, with 7 karyomorphs identified. Karyomorph A is characterized by 2n = 42 chromosomes, without morphologically differentiated sex chromosomes. Karyomorph B also has 2n = 42 chromosomes for both sexes, but differs by a distinct heteromorphic XX/XY sex chromosome system. The cytogenetic mapping of 5 classes of repetitive DNA indicated similarities between both karyomorphs and the probable derivation of the XY chromosomes from pair No. 21 of karyomorph A. These chromosomes appear to be homeologous since the distribution of (GATA)(n) sequences, 18S rDNA and 5SHindIII-DNA sites supports their potential relatedness. Our data indicate that the differentiation of the long arms of the X chromosome occurred by accumulation of heterochromatin and 18S rDNA cistrons from the ancestral homomorphic pair No. 21 present in karyomorph A. These findings are further supported by the distribution of the Cot-1 DNA fraction. In addition, while the 18S rDNA cistrons were maintained and amplified on the X chromosomes, they were lost in the Y chromosome. The X chromosome was a clearly preferred site for the accumulation of DNA repeats, representing an unusual example of an X clustering more repetitive sequences than the Y during sex chromosome differentiation in fish.

  20. Location of a High-Lysine Gene and the DDT-Resistance Gene on Barley Chromosome 7

    DEFF Research Database (Denmark)

    Jensen, J.

    1979-01-01

    mutants, nos 1508.18, and 19. Linkage studies with translocations locate the Lys3 locus in the centromere region ofchromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker locifi (fragile stem), s(short rachilla hairs), and r (smooth awn) show...... that the order of the five loci on chromosome 7 from the long to the short chromosome arm is Y, s,fi, lys3, ddt. The distance from locus I to locus ddt is about 100 centimorgans....

  1. Novel homozygous mutation in DSP causing skin fragility-woolly hair syndrome: report of a large family and review of the desmoplakin-related phenotypes.

    Science.gov (United States)

    Al-Owain, M; Wakil, S; Shareef, F; Al-Fatani, A; Hamadah, E; Haider, M; Al-Hindi, H; Awaji, A; Khalifa, O; Baz, B; Ramadhan, R; Meyer, B

    2011-07-01

    Desmoplakin is an important cytoskeletal linker for the function of the desmosomes. Linking desmoplakin to certain types of cardiocutaneous syndromes has been a hot topic recently. Skin fragility-woolly hair syndrome is a rare autosomal recessive disorder involving the desmosomes and is caused by mutation in the desmoplakin gene (DSP). We report five members from a large family with skin fragility-woolly hair syndrome. The index is a 14-year-old girl with palmoplantar keratoderma, woolly hair, variable alopecia, dystrophic nails, and excessive blistering to trivial mechanical trauma. No cardiac symptoms were reported. Although formal cardiac examination was not feasible, the echocardiographic evaluation of the other two affected younger siblings was normal. Homozygosity mapping and linkage analysis revealed a high LOD score region in the short arm of chromosome 6 that harbors the DSP. Full sequencing of the DSP showed a novel homozygous c.7097 G>A (p.R2366H) mutation in all affected members, and the parents were heterozygous. This is the report of the third case/family of the skin fragility-woolly hair syndrome in the literature. We also present a clinical and molecular review of various desmoplakin-related phenotypes, with emphasis on onset of cardiomyopathy. The complexity of the desmoplakin and its variable presentations warrant introducing the term 'desmoplakinopathies' to describe all the phenotypes related to defects in the desmoplakin.

  2. Chromosomal rearrangements in cattle and pigs revealed by chromosome microdissection and chromosome painting

    Directory of Open Access Journals (Sweden)

    Yerle Martine

    2003-11-01

    Full Text Available Abstract A pericentric inversion of chromosome 4 in a boar, as well as a case of (2q-;5p+ translocation mosaicism in a bull were analysed by chromosome painting using probes generated by conventional microdissection. For the porcine inversion, probes specific for p arms and q arms were produced and hybridised simultaneously on metaphases of a heterozygote carrier. In the case of the bovine translocation, two whole chromosome probes (chromosome 5, and derived chromosome 5 were elaborated and hybridised independently on chromosomal preparations of the bull who was a carrier of the mosaic translocation. The impossibility of differentiating chromosomes 2 and der(2 from other chromosomes of the metaphases did not allow the production of painting probes for these chromosomes. For all experiments, the quality of painting was comparable to that usually observed with probes obtained from flow-sorted chromosomes. The results obtained allowed confirmation of the interpretations proposed with G-banding karyotype analyses. In the bovine case, however, the reciprocity of the translocation could not be proven. The results presented in this paper show the usefulness of the microdissection technique for characterising chromosomal rearrangements in species for which commercial probes are not available. They also confirmed that the main limiting factor of the technique is the quality of the chromosomal preparations, which does not allow the identification of target chromosomes or chromosome fragments in all cases.

  3. Structural Studies of the Tandem Tudor Domains of Fragile X Mental Retardation Related Proteins FXR1 and FXR2

    Energy Technology Data Exchange (ETDEWEB)

    Adams-Cioaba, Melanie A.; Guo, Yahong; Bian, ChuanBing; Amaya, Maria F.; Lam, Robert; Wasney, Gregory A.; Vedadi, Masoud; Xu, Chao; Min, Jinrong (Toronto)

    2011-11-23

    Expansion of the CGG trinucleotide repeat in the 5'-untranslated region of the FMR1, fragile X mental retardation 1, gene results in suppression of protein expression for this gene and is the underlying cause of Fragile X syndrome. In unaffected individuals, the FMRP protein, together with two additional paralogues (Fragile X Mental Retardation Syndrome-related Protein 1 and 2), associates with mRNA to form a ribonucleoprotein complex in the nucleus that is transported to dendrites and spines of neuronal cells. It is thought that the fragile X family of proteins contributes to the regulation of protein synthesis at sites where mRNAs are locally translated in response to stimuli. Here, we report the X-ray crystal structures of the non-canonical nuclear localization signals of the FXR1 and FXR2 autosomal paralogues of FMRP, which were determined at 2.50 and 1.92 {angstrom}, respectively. The nuclear localization signals of the FXR1 and FXR2 comprise tandem Tudor domain architectures, closely resembling that of UHRF1, which is proposed to bind methylated histone H3K9. The FMRP, FXR1 and FXR2 proteins comprise a small family of highly conserved proteins that appear to be important in translational regulation, particularly in neuronal cells. The crystal structures of the N-terminal tandem Tudor domains of FXR1 and FXR2 revealed a conserved architecture with that of FMRP. Biochemical analysis of the tandem Tudor doamins reveals their ability to preferentially recognize trimethylated peptides in a sequence-specific manner.

  4. Structural studies of the tandem Tudor domains of fragile X mental retardation related proteins FXR1 and FXR2.

    Directory of Open Access Journals (Sweden)

    Melanie A Adams-Cioaba

    Full Text Available BACKGROUND: Expansion of the CGG trinucleotide repeat in the 5'-untranslated region of the FMR1, fragile X mental retardation 1, gene results in suppression of protein expression for this gene and is the underlying cause of Fragile X syndrome. In unaffected individuals, the FMRP protein, together with two additional paralogues (Fragile X Mental Retardation Syndrome-related Protein 1 and 2, associates with mRNA to form a ribonucleoprotein complex in the nucleus that is transported to dendrites and spines of neuronal cells. It is thought that the fragile X family of proteins contributes to the regulation of protein synthesis at sites where mRNAs are locally translated in response to stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the X-ray crystal structures of the non-canonical nuclear localization signals of the FXR1 and FXR2 autosomal paralogues of FMRP, which were determined at 2.50 and 1.92 Å, respectively. The nuclear localization signals of the FXR1 and FXR2 comprise tandem Tudor domain architectures, closely resembling that of UHRF1, which is proposed to bind methylated histone H3K9. CONCLUSIONS: The FMRP, FXR1 and FXR2 proteins comprise a small family of highly conserved proteins that appear to be important in translational regulation, particularly in neuronal cells. The crystal structures of the N-terminal tandem Tudor domains of FXR1 and FXR2 revealed a conserved architecture with that of FMRP. Biochemical analysis of the tandem Tudor domains reveals their ability to preferentially recognize trimethylated peptides in a sequence-specific manner. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1.

  5. Prevalence and predictors of low bone density and fragility fractures in women with systemic lupus erythematosus in a Mediterranean region.

    Science.gov (United States)

    Salman-Monte, Tarek Carlos; Torrente-Segarra, Vicenç; Muñoz-Ortego, Juan; Mojal, Sergi; Carbonell-Abelló, Jordi

    2015-03-01

    Studies have found an increase in bone loss and fracture in individuals with systemic lupus erythematosus (SLE) compared with general population. The aim of this study was to describe the prevalence of osteopenia, osteoporosis, and fragility fractures and to find potential predictors of bone loss in our cohort of SLE patients. We performed a cross-sectional study and collected 67 bone density measurements (BMD) of our SLE patients. We also collected sociodemographic data, 25-OH-vitamin D levels, serological markers, activity index, SLE cumulative damage index, and pharmacologic treatment. Sixty-seven consecutive BMD from SLE patients were assessed. Osteopenia was found in 28-46% of SLE patients. Osteoporosis ranged from 3 to 6%[corrected]. The only statistically significant correlation we found was between weight and height with total hip and femoral neck BMD (p < 0.05). The most frequent BMD-affected site was at the femoral neck, showing osteopenia in 40.3% [corrected] of SLE patients. Osteoporosis was found in up to 6% [corrected] of SLE patients. We found no predictors of bone loss in relation to the disease activity or its treatment. Fragility fractures were seen in 4.4% of SLE patients. All patients with fragility fractures showed osteopenia at BMD. There is a high prevalence of bone loss in SLE patients, since up to 40% [corrected] of SLE patients showed low BMD. Total hip and femoral neck osteopenia were the most frequent findings correlated with low BMI. We found a lower prevalence of fragility fractures compared with other series.

  6. Chromosomal rearrangement interferes with meiotic X chromosome inactivation

    OpenAIRE

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-01-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X–autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencin...

  7. Germinal mosaicism for a deletion of the FMR1 gene leading to fragile X syndrome.

    Science.gov (United States)

    Jiraanont, P; Hagerman, R J; Neri, G; Zollino, M; Murdolo, M; Tassone, F

    2016-09-01

    Aberrant CGG trinucleotide amplification within the FMR1 gene, which spans approximately 38 Kb of genomic DNA is almost always what leads to fragile X syndrome (FXS). However, deletions of part or the entire FMR1 gene can also cause FXS. Both CGG amplification-induced silencing and deletions result in the absence of the FMR1 gene product, FMRP. Here, we report a rare case of germinal mosaicism of a deletion encompassing approximately 300 Kb of DNA, which by removing the entire FMR1 gene led to FXS. The male proband, carrying the deletion, presented in clinic with the typical features of FXS. His mother was analyzed by FISH on metaphase chromosomes with cosmid probe c22.3 spanning the FMR1 locus, and she was found not to carry the deletion on 30 analyzed cells from peripheral blood lymphocytes. Prenatal examination of the mother's third pregnancy showed that the male fetus also had the same deletion as the proband. Following this prenatal diagnosis, FISH analysis in the mother was expanded to 400 metaphases from peripheral lymphocytes, and a heterozygous FMR1 deletion was found in three. Although this result could be considered questionable from a diagnostic point of view, it indicates that the deletion is in the ovary's germinal cells.

  8. Identification of Mitosis-Specific Phosphorylation in Mitotic Chromosome-Associated Proteins.

    Science.gov (United States)

    Ohta, Shinya; Kimura, Michiko; Takagi, Shunsuke; Toramoto, Iyo; Ishihama, Yasushi

    2016-09-01

    During mitosis, phosphorylation of chromosome-associated proteins is a key regulatory mechanism. Mass spectrometry has been successfully applied to determine the complete protein composition of mitotic chromosomes, but not to identify post-translational modifications. Here, we quantitatively compared the phosphoproteome of isolated mitotic chromosomes with that of chromosomes in nonsynchronized cells. We identified 4274 total phosphorylation sites and 350 mitosis-specific phosphorylation sites in mitotic chromosome-associated proteins. Significant mitosis-specific phosphorylation in centromere/kinetochore proteins was detected, although the chromosomal association of these proteins did not change throughout the cell cycle. This mitosis-specific phosphorylation might play a key role in regulation of mitosis. Further analysis revealed strong dependency of phosphorylation dynamics on kinase consensus patterns, thus linking the identified phosphorylation sites to known key mitotic kinases. Remarkably, chromosomal axial proteins such as non-SMC subunits of condensin, TopoIIα, and Kif4A, together with the chromosomal periphery protein Ki67 involved in the establishment of the mitotic chromosomal structure, demonstrated high phosphorylation during mitosis. These findings suggest a novel mechanism for regulation of chromosome restructuring in mitosis via protein phosphorylation. Our study generated a large quantitative database on protein phosphorylation in mitotic and nonmitotic chromosomes, thus providing insights into the dynamics of chromatin protein phosphorylation at mitosis onset.

  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. Chromosome Variations And Human Behavior

    Science.gov (United States)

    Soudek, D.

    1974-01-01

    Article focused on the science of cytogenetics, which studied the transmission of the units of heredity called chromosomes, and considered the advantage of proper diagnosis of genetic diseases, treated on the chromosomal level. (Author/RK)

  11. Molecular mapping of chromosomes 17 and X

    Energy Technology Data Exchange (ETDEWEB)

    Barker, D.F.

    1989-01-01

    The basic aims of this project are the construction of high density genetic maps of chromosomes 17 and X and the utilization of these maps for the subsequent isolation of a set of physically overlapping DNA segment clones. The strategy depends on the utilization of chromosome specific libraries of small (1--15 kb) segments from each of the two chromosomes. Since the time of submission of our previous progress report, we have refined the genetic map of markers which we had previously isolated for chromosome 17. We have completed our genetic mapping in CEPH reference and NF1 families of 15 markers in the pericentric region of chromosome 17. Physical mapping results with three probes, were shown be in very close genetic proximity to the NF1 gene, with respect to two translocation breakpoints which disrupt the activity of the gene. All three of the probes were found to lie between the centromere and the most proximal translocation breakpoint, providing important genetic markers proximal to the NF1 gene. Our primary focus has shifted to the X chromosome. We have isolated an additional 30 polymorphic markers, bringing the total number we have isolated to over 80. We have invested substantial effort in characterizing the polymorphisms at each of these loci and constructed plasmid subclones which reveal the polymorphisms for nearly all of the loci. These subclones are of practical value in that they produce simpler and stronger patterns on human genomic Southern blots, thus improving the efficiency of the genetic mapping experiments. These subclones may also be of value for deriving DNA sequence information at each locus, necessary for establishing polymerase chain reaction primers specific for each locus. Such information would allow the use of each locus as a sequence tagged site.

  12. 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...

  13. Chromosomes, cancer and radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Samouhos, E.

    1983-08-01

    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.

  14. The Y Chromosome

    Science.gov (United States)

    Offner, Susan

    2010-01-01

    The Y chromosome is of great interest to students and can be used to teach about many important biological concepts in addition to sex determination. This paper discusses mutation, recombination, mammalian sex determination, sex determination in general, and the evolution of sex determination in mammals. It includes a student activity that…

  15. Why Chromosome Palindromes?

    Directory of Open Access Journals (Sweden)

    Esther Betrán

    2012-01-01

    Full Text Available We look at sex-limited chromosome (Y or W evolution with particular emphasis on the importance of palindromes. Y chromosome palindromes consist of inverted duplicates that allow for local recombination in an otherwise nonrecombining chromosome. Since palindromes enable intrachromosomal gene conversion that can help eliminate deleterious mutations, they are often highlighted as mechanisms to protect against Y degeneration. However, the adaptive significance of recombination resides in its ability to decouple the evolutionary fates of linked mutations, leading to both a decrease in degeneration rate and an increase in adaptation rate. Our paper emphasizes the latter, that palindromes may exist to accelerate adaptation by increasing the potential targets and fixation rates of incoming beneficial mutations. This hypothesis helps reconcile two enigmatic features of the “palindromes as protectors” view: (1 genes that are not located in palindromes have been retained under purifying selection for tens of millions of years, and (2 under models that only consider deleterious mutations, gene conversion benefits duplicate gene maintenance but not initial fixation. We conclude by looking at ways to test the hypothesis that palindromes enhance the rate of adaptive evolution of Y-linked genes and whether this effect can be extended to palindromes on other chromosomes.

  16. Equipment fragility data base. Seismic Safety Margins Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Cover, L.E.

    1983-01-10

    Part of the effort of the Seismic Safety Margins Research Program (SSMRP) has been directed at generating a fragility data base for equipment used in control and safety systems in commercial nuclear power plants. Component fragility data have been compiled in various forms, depending on their content, intended use, and level of reduction. The data are stored in a relational data base on the LLNL CEC 7600 computers; this provides easy accessibility for LLNL computer users. This report describes the present structure of the data base and presents its contents through the use of tables. This report is a revision of an earlier one of the same name and numbers (NUREG/CR-2680) and (UCRL-53038). Additional data have been included and the presentation has been revised to enhance its usability.

  17. Sequence analysis of the fragile X trinucleotide repeat: Correlations with stability and haplotype and implications for the origin of fragile X alleles

    Energy Technology Data Exchange (ETDEWEB)

    Snow, K.; Tester, D.J.; Kruckeberg, K.E.; Thibodeau, S.N. [Mayo Clinic, Rochester, MN (United States)

    1994-09-01

    Fragile X (FX) syndrome is associated with amplification of a CGG trinucleotide repeat in the 5{prime} untranslated region of the gene FMR-1. To address mechanism of instability and concern related to overlap between sizes of normal stable alleles and FX unstable alleles, we have sequenced 165 alleles to analyze patterns of AGG interruptions within the CGG repeat, and have typed the (CA)n at DXS548 for 204 chromosomes. Overall, our data is consistent with the idea that the length of uninterrupted CGG repeats determines instability. For 17 stably transmitted alleles with total repeat lengths between 33 and 51, the longest stretch of uninterrupted CGGs was 41. In contrast, for 13 premutation alleles, the shortest stretch of uninterrupted CGGs was 48, suggesting a threshold for expansion between 41 and 48 pure CGGs. For expansion from a premutation to a full mutation, the threshold appears to be {ge}70 uninterrupted repeats. Interestingly, an AGG was detected in some carriers of a full mutation. Comparison of the number of {open_quote}shadow bands{close_quote} in PCR products from similar size alleles with different AGG interruption patterns supports replication slippage as a potential mechanism, i.e. replication slippage occurs more readily as the length of pure repeat increases. Alleles with high total repeat lengths but up to 3 AGGs may be relatively protected against expansion, whereas smaller alleles with pure CGG sequence could be at higher risk for instability. Comparison of sequence data and DXS548 (CA)n data revealed specific sequence trends for each of the DXS548 alleles, explaining the previously reported haplotype association with FX. Incorporating these observations into models for the origin of FX alleles, we consider replication slippage, unequal crossover within the CGG repeat region, recombination between FMR-1 and DXS548, and loss of AGGs by A to C transversion.

  18. 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

  19. Strong to fragile transition in a model of liquid silica

    OpenAIRE

    Barrat, Jean-Louis; Badro, James; Gillet, Philippe

    1996-01-01

    The transport properties of an ionic model for liquid silica at high temperatures and pressure are investigated using molecular dynamics simulations. With increasing pressure, a clear change from "strong" to "fragile" behaviour (according to Angell's classification of glass-forming liquids) is observed, albeit only on the small viscosity range that can be explored in MD simulations.. This change is related to structural changes, from an almost perfect four-fold coordination to an imperfect fi...

  20. Craniofacial characteristics of fragile X syndrome in mouse and man

    OpenAIRE

    2012-01-01

    For a disorder as common as fragile X syndrome, the most common hereditary form of cognitive impairment, the facial features are relatively ill defined. An elongated face and prominent ears are the most commonly accepted dysmorphic hallmarks. We analysed 3D facial photographs of 51 males and 15 females with full FMR1 mutations and 9 females with a premutation using dense-surface modelling techniques and a new technique that forms a directed graph with normalized face shapes as nodes and edges...

  1. Matrix Metalloproteinases and Minocycline: Therapeutic Avenues for Fragile X Syndrome

    OpenAIRE

    Siller, Saul S; Kendal Broadie

    2012-01-01

    Fragile X syndrome (FXS) is the most common known genetic form of intellectual disability and autism spectrum disorders. FXS patients suffer a broad range of other neurological symptoms, including hyperactivity, disrupted circadian activity cycles, obsessive-compulsive behavior, and childhood seizures. The high incidence and devastating effects of this disease state make finding effective pharmacological treatments imperative. Recently, reports in both mouse and Drosophila FXS disease models ...

  2. Systematic review of pharmacological treatments in fragile X syndrome

    OpenAIRE

    Rueda Martínez de Santos, José Ramón; Ballesteros Rodríguez, Francisco Javier; Tejada, María Isabel

    2009-01-01

    Es rerproducción del documento publicado en http://dx.doi.org/10.1186/1471-2377-9-53 Background: Fragile X syndrome (FXS) is considered the most common cause of inherited mental retardation. Affected people have mental impairment that can include Attention Deficit and/or Hyperactivity Disorder (ADHD), autism disorder, and speech and behavioural disorders. Several pharmacological interventions have been proposed to treat those impairments. Methods: Systematic review of the literature and...

  3. Systematic review of pharmacological treatments in fragile X syndrome

    OpenAIRE

    Rueda, Jose-Ramon; BALLESTEROS, JAVIER; Tejada, Maria-Isabel

    2009-01-01

    Background Fragile X syndrome (FXS) is considered the most common cause of inherited mental retardation. Affected people have mental impairment that can include Attention Deficit and/or Hyperactivity Disorder (ADHD), autism disorder, and speech and behavioural disorders. Several pharmacological interventions have been proposed to treat those impairments. Methods Systematic review of the literature and summary of the evidence from clinical controlled trials that compared at least one pharmacol...

  4. Systematic review of pharmacological treatments in fragile X syndrome

    OpenAIRE

    Tejada Maria-Isabel; Ballesteros Javier; Rueda Jose-Ramon

    2009-01-01

    Abstract Background Fragile X syndrome (FXS) is considered the most common cause of inherited mental retardation. Affected people have mental impairment that can include Attention Deficit and/or Hyperactivity Disorder (ADHD), autism disorder, and speech and behavioural disorders. Several pharmacological interventions have been proposed to treat those impairments. Methods Systematic review of the literature and summary of the evidence from clinical controlled trials that compared at least one ...

  5. [Dicentric Y chromosome].

    Science.gov (United States)

    Abdelmoula, N Bouayed; Amouri, A

    2005-01-01

    Dicentric Y chromosomes are the most common Y structural abnormalities and their influence on gonadal and somatic development is extremely variable. Here, we report the third comprehensive review of the literature concerning dicentric Y chromosomes reported since 1994. We find 78 new cases for which molecular studies (PCR or FISH) have been widely applied to investigate SRY (68% of cases), GBY, ZFY, RFS4Y, GCY and different genes at AZF region. For dic(Yq), all cases (n = 20) were mosaic for 45,X and 4 of them were also mosaic for a 46,XY cell line. When breakpoints were available (15/20 cases), they were in Yp11. 50% of cases were phenotypic female and 20% phenotypic male while 20% of cases were reported with gonadal dysgenesis. Gonadal histology was defined in 8 cases but only in one case, gonadal tissu was genetically investigated because of gonadoblastoma. For dic(Yp) (n = 55), mosaicism concerned only 45,X cell line and was found in 50 cases while the remainder five cases were homogeneous. When breakpoints were available, it was at Yq11 in 50 cases and at Yq12 in two cases. 54% of cases were phenotypic female, 26% were phenotypic male and 18% were associated with genitalia ambiguous. SRY was analyzed in 33 cases, sequenced in 9 cases and was muted in only one case. Gonads were histologically explored in 34 cases and genetically investigated in 8 cases. Gonadoblastoma was found in only two cases. Through this review, it seems that phenotype-genotype correlations are still not possible and that homogeneous studies of dic(Y) in more patients using molecular tools for structural characterization of the rearranged Y chromosome and assessment of mosaicism in many organs are necessary to clarify the basis of the phenotypic heterogeneity of dicentric Y chromosomes and then to help phenotypic prediction of such chromosome rearrangement.

  6. Screening and diagnosis for the fragile X syndrome among the mentally retarded: an epidemiological and psychological survey. Collaborative Fragile X Study Group

    NARCIS (Netherlands)

    B.B.A. de Vries (Bert); B.A. Oostra (Ben); M.F. Niermeijer (Martinus); A. Tibben (Arend); A.M.W. van den Ouweland (Ans); S. Mohkamsing; H.J. Duivenvoorden (Hugo); E. Mol; K. Gelsema; M. van Rijn; D.J.J. Halley (Dicky); L.A. Sandkuijl (Lodewijk)

    1997-01-01

    textabstractThe fragile X syndrome is an X-linked mental retardation disorder caused by an expanded CGG repeat in the first exon of the fragile X mental retardation (FMR1) gene. Its frequency, X-linked inheritance, and consequences for relatives all prompt for diagnosis

  7. Fragile X-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Hagerman, Paul J; Hagerman, Randi J

    2015-03-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some but not all carriers of small, noncoding CGG-repeat expansions (55-200 repeats; premutation) within the fragile X gene (FMR1). Principal features of FXTAS include intention tremor, cerebellar ataxia, Parkinsonism, memory and executive function deficits, autonomic dysfunction, brain atrophy with white matter disease, and cognitive decline. Although FXTAS was originally considered to be confined to the premutation range, rare individuals with a gray zone (45-54 repeats) or an unmethylated full mutation (>200 repeats) allele have now been described, the constant feature of the disorder remaining the requirement for FMR1 expression, in contradistinction to the gene silencing mechanism of fragile X syndrome. Although transcriptional activity is required for FXTAS pathogenesis, the specific trigger(s) for FXTAS pathogenesis remains elusive, highlighting the need for more research in this area. This need is underscored by recent neuroimaging findings of changes in the central nervous system that consistently appear well before the onset of clinical symptoms, thus creating an opportunity to delay or prevent the appearance of FXTAS.

  8. Craniofacial characteristics of fragile X syndrome in mouse and man.

    Science.gov (United States)

    Heulens, Inge; Suttie, Michael; Postnov, Andrei; De Clerck, Nora; Perrotta, Concetta S; Mattina, Teresa; Faravelli, Francesca; Forzano, Francesca; Kooy, R Frank; Hammond, Peter

    2013-08-01

    For a disorder as common as fragile X syndrome, the most common hereditary form of cognitive impairment, the facial features are relatively ill defined. An elongated face and prominent ears are the most commonly accepted dysmorphic hallmarks. We analysed 3D facial photographs of 51 males and 15 females with full FMR1 mutations and 9 females with a premutation using dense-surface modelling techniques and a new technique that forms a directed graph with normalized face shapes as nodes and edges linking those with closest dysmorphism. In addition to reconfirming known features, we confirmed the occurrence of some at an earlier age than previously recorded. We also identified as yet unrecorded facial characteristics such as reduced facial depth, hypoplasticity of the nasal bone-cartilage interface and narrow mid-facial width exaggerating ear prominence. As no consistent craniofacial abnormalities had been reported in animal models, we analysed micro-CT images of the fragile X mouse model. Results indicated altered dimensions in the mandible and both outer and inner skull, with the latter potentially reflecting differences in neuroanatomy. We extrapolated the mouse results to face shape differences of the human fragile X face.

  9. Premature ovarian failure (POF in Brazilian fragile X carriers

    Directory of Open Access Journals (Sweden)

    Angela M. Vianna-Morgante

    1999-12-01

    Full Text Available The gynecological and reproductive histories of 193 women from fragile X families were surveyed. Among the 101 carriers of the premutation, 14 experienced premature menopause, contrarily to their 37 fully mutated and 55 noncarrier female relatives. Although premature menopause showed a tendency to cluster in certain fragile X families, as a group, the premutated women experienced menopause earlier than noncarriers. This suggests that premature menopause may be the extreme effect of a spectrum of ovarian anomalies associated with the fragile X premutation.Entrevistamos 193 mulheres de famílias com afetados pela síndrome do cromossomo X frágil, quanto a sua história ginecológica e reprodutiva. Entre as 101 portadoras da pré-mutação, 14 tiveram menopausa precoce, mas nenhuma das 37 portadoras da mutação completa ou das 55 não portadoras apresentaram esta anomalia. Observamos uma tendência para a concentração da menopausa precoce em certas famílias, o que poderia significar uma peculiariedade de certas pré-mutações. Entretanto, o fato de as mulheres pré-mutadas tenderem a entrar em menopausa mais cedo do que as não portadoras sugere que a menopausa precoce seja o extremo do espectro de efeitos ovarianos da pré-mutação.

  10. Partnership for fragility bone fracture care provision and prevention program (P4Bones: study protocol for a secondary fracture prevention pragmatic controlled trial

    Directory of Open Access Journals (Sweden)

    Gaboury Isabelle

    2013-01-01

    Full Text Available Abstract Background Fractures associated with bone fragility in older adults signal the potential for secondary fracture. Fragility fractures often precipitate further decline in health and loss of mobility, with high associated costs for patients, families, society and the healthcare system. Promptly initiating a coordinated, comprehensive pharmacological bone health and falls prevention program post-fracture may improve osteoporosis treatment compliance; and reduce rates of falls and secondary fractures, and associated morbidity, mortality and costs. Methods/design This pragmatic, controlled trial at 11 hospital sites in eight regions in Quebec, Canada, will recruit community-dwelling patients over age 50 who have sustained a fragility fracture to an intervention coordinated program or to standard care, according to the site. Site study coordinators will identify and recruit 1,596 participants for each study arm. Coordinators at intervention sites will facilitate continuity of care for bone health, and arrange fall prevention programs including physical exercise. The intervention teams include medical bone specialists, primary care physicians, pharmacists, nurses, rehabilitation clinicians, and community program organizers. The primary outcome of this study is the incidence of secondary fragility fractures within an 18-month follow-up period. Secondary outcomes include initiation and compliance with bone health medication; time to first fall and number of clinically significant falls; fall-related hospitalization and mortality; physical activity; quality of life; fragility fracture-related costs; admission to a long term care facility; participants’ perceptions of care integration, expectations and satisfaction with the program; and participants’ compliance with the fall prevention program. Finally, professionals at intervention sites will participate in focus groups to identify barriers and facilitating factors for the integrated

  11. Dynamics of X Chromosome Inactivation

    NARCIS (Netherlands)

    F. Loos (Friedemann)

    2015-01-01

    markdownabstract__Abstract__ Dosage compensation evolved to account for the difference in expression of sex chromosome-linked genes. In mammals dosage compensation is achieved by inactivation of one X chromosome during early female embryogenesis in a process called X chromosome inactivation (XCI).

  12. HIM-8 binds to the X chromosome pairing center and mediateschromosome-specific meiotic synapsis

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Carolyn M.; Wong, Chihunt; Bhalla, Needhi; Carlton,Peter M.; Weiser, Pinky; Meneely, Philip M.; Dernburg, Abby F.

    2005-06-05

    The him-8 gene is essential for proper meiotic segregationof the X chromosomes in C. elegans. Herewe show that loss of him-8function causes profound X-chromosome-specific defects in homolog pairingand synapsis.him-8 encodes a C2H2 zinc finger protein that is expressedduring meiosis andconcentrates at a site on the X chromosome known as themeiotic Pairing Center (PC). A role for HIM-8 in PC function is supportedby 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 thatretains both chromosome binding and NE localization fails to stabilizepairing or promote synapsis. These observations indicate thatstabilization of homolog pairing is an active process in which thetethering of chromosome sites to the NE may be necessary but is notsufficient.

  13. Chromosomal breakpoints characterization of two supernumerary ring chromosomes 20.

    Science.gov (United States)

    Guediche, N; Brisset, S; Benichou, J-J; Guérin, N; Mabboux, P; Maurin, M-L; Bas, C; Laroudie, M; Picone, O; Goldszmidt, D; Prévot, S; Labrune, P; Tachdjian, G

    2010-02-01

    The occurrence of an additional ring chromosome 20 is a rare chromosome abnormality, and no common phenotype has been yet described. We report on two new patients presenting with a supernumerary ring chromosome 20 both prenatally diagnosed. The first presented with intrauterine growth retardation and some craniofacial dysmorphism, and the second case had a normal phenotype except for obesity. Conventional cytogenetic studies showed for each patient a small supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization, these SMCs corresponded to ring chromosomes 20 including a part of short and long arms of chromosome 20. Detailed molecular cytogenetic characterization showed different breakpoints (20p11.23 and 20q11.23 for Patient 1 and 20p11.21 and 20q11.21 for Patient 2) and sizes of the two ring chromosomes 20 (13.6 Mb for case 1 and 4.8 Mb for case 2). Review of the 13 case reports of an extra r(20) ascertained postnatally (8 cases) and prenatally (5 cases) showed varying degrees of phenotypic abnormalities. We document a detailed molecular cytogenetic chromosomal breakpoints characterization of two cases of supernumerary ring chromosomes 20. These results emphasize the need to characterize precisely chromosomal breakpoints of supernumerary ring chromosomes 20 in order to establish genotype-phenotype correlation. This report may be helpful for prediction of natural history and outcome, particularly in prenatal diagnosis.

  14. Familial complex chromosomal rearrangement resulting in a recombinant chromosome.

    Science.gov (United States)

    Berend, Sue Ann; Bodamer, Olaf A F; Shapira, Stuart K; Shaffer, Lisa G; Bacino, Carlos A

    2002-05-15

    Familial complex chromosomal rearrangements (CCRs) are rare and tend to involve fewer breakpoints and fewer chromosomes than CCRs that are de novo in origin. We report on a CCR identified in a child with congenital heart disease and dysmorphic features. Initially, the child's karyotype was thought to involve a straightforward three-way translocation between chromosomes 3, 8, and 16. However, after analyzing the mother's chromosomes, the mother was found to have a more complex rearrangement that resulted in a recombinant chromosome in the child. The mother's karyotype included an inverted chromosome 2 and multiple translocations involving chromosomes 3, 5, 8, and 16. No evidence of deletion or duplication that could account for the clinical findings in the child was identified.

  15. Cytogenetic Insights into the Evolution of Chromosomes and Sex Determination Reveal Striking Homology of Turtle Sex Chromosomes to Amphibian Autosomes.

    Science.gov (United States)

    Montiel, Eugenia E; Badenhorst, Daleen; Lee, Ling S; Literman, Robert; Trifonov, Vladimir; Valenzuela, Nicole

    2016-01-01

    Turtle karyotypes are highly conserved compared to other vertebrates; yet, variation in diploid number (2n = 26-68) reflects profound genomic reorganization, which correlates with evolutionary turnovers in sex determination. We evaluate the published literature and newly collected comparative cytogenetic data (G- and C-banding, 18S-NOR, and telomere-FISH mapping) from 13 species spanning 2n = 28-68 to revisit turtle genome evolution and sex determination. Interstitial telomeric sites were detected in multiple lineages that underwent diploid number and sex determination turnovers, suggesting chromosomal rearrangements. C-banding revealed potential interspecific variation in centromere composition and interstitial heterochromatin at secondary constrictions. 18S-NORs were detected in secondary constrictions in a single chromosomal pair per species, refuting previous reports of multiple NORs in turtles. 18S-NORs are linked to ZW chromosomes in Apalone and Pelodiscus and to X (not Y) in Staurotypus. Notably, comparative genomics across amniotes revealed that the sex chromosomes of several turtles, as well as mammals and some lizards, are homologous to components of Xenopus tropicalis XTR1 (carrying Dmrt1). Other turtle sex chromosomes are homologous to XTR4 (carrying Wt1). Interestingly, all known turtle sex chromosomes, except in Trionychidae, evolved via inversions around Dmrt1 or Wt1. Thus, XTR1 appears to represent an amniote proto-sex chromosome (perhaps linked ancestrally to XTR4) that gave rise to turtle and other amniote sex chromosomes.

  16. Regulation of chromosomal replication in Caulobacter crescentus.

    Science.gov (United States)

    Collier, Justine

    2012-03-01

    The alpha-proteobacterium Caulobacter crescentus is characterized by its asymmetric cell division, which gives rise to a replicating stalked cell and a non-replicating swarmer cell. Thus, the initiation of chromosomal replication is tightly regulated, temporally and spatially, to ensure that it is coordinated with cell differentiation and cell cycle progression. Waves of DnaA and CtrA activities control when and where the initiation of DNA replication will take place in C. crescentus cells. The conserved DnaA protein initiates chromosomal replication by directly binding to sites within the chromosomal origin (Cori), ensuring that DNA replication starts once and only once per cell cycle. The CtrA response regulator represses the initiation of DNA replication in swarmer cells and in the swarmer compartment of pre-divisional cells, probably by competing with DnaA for binding to Cori. CtrA and DnaA are controlled by multiple redundant regulatory pathways that include DNA methylation-dependent transcriptional regulation, temporally regulated proteolysis and the targeting of regulators to specific locations within the cell. Besides being critical regulators of chromosomal replication, CtrA and DnaA are also master transcriptional regulators that control the expression of many genes, thus connecting DNA replication with other events of the C. crescentus cell cycle.

  17. Y chromosome microdeletions in Turkish infertile men

    Directory of Open Access Journals (Sweden)

    Zamani Ayse

    2006-01-01

    Full Text Available AIMS: To detect the frequency and types of both chromosomal abnormalities and Y chromosome microdeletions in infertile men attending to our university intracytoplasmic sperm injection ICSI/IVF centre and fertile control subjects in our patient population. SETTINGS AND DESIGN: A total of 50 infertile men who were referred to IVF center of Meram medical faculty were selected for the molecular azospermia factor (AZF screening program. MATERIALS AND METHODS: Karyotype analysis and polymerase chain reaction amplification using 15 Y-specific sequence-tagged sites of AZF region were done. RESULTS: The total prevalence of chromosomal abnormalities was found to be 10% (5/50, including 4 patients with numerical and 1 patient with structural abnormalities. Overall, 4 of the 50 patients tested (8% exhibited deletions of the Y chromosome, 3 of them being azospermic and 1 of them oligospermic men. The frequency of the microdeletions in subgroups with azospermia and oligozoospermia was found to be 10.7% (3/29 and 4.7% (1/21 respectively. Microdeletions of AZFb and AZFc regions were detected in all of the 4 patients. Neither AZFa nor AZFd microdeletions were indicated. CONCLUSIONS: Our findings suggest that one must know whether there is a genetic cause for male infertility before patients can be subjected to ISCI or testicular sperm extraction (TESE/ISCI treatment.

  18. Sister chromatid exchange assessment by chromosome orientation-fluorescence in situ hybridization on the bovine sex chromosomes and autosomes 16 and 26.

    Science.gov (United States)

    Revay, T; King, W A

    2012-01-01

    Mammalian genome replication and maintenance are intimately coupled with the mechanisms that ensure cohesion between the resultant sister chromatids and the repair of DNA breaks. Although a sister chromatid exchange (SCE) is an error-free swapping of precisely matched and identical DNA strands, repetitive elements adjacent to the break site can act as alternative template sites and an unequal sister chromatid exchange can result, leading to structural variations and copy number change. Here we test the vulnerability for SCEs of the repeat-rich bovine Y chromosome in comparison with X, 16 and 26 chromosomes, using chromosome orientation-fluorescence in situ hybridization. The mean SCE rate of the Y chromosome (0.065 ± 0.029) was similar to that of BTA16 and BTA26 (0.065, 0.055), but was only approximately half of that of the X chromosome (0.142). As the chromosomal length affects the number of SCE events, we adjusted the SCE rates of the Y, 16, and 26 chromosomes to the length of the largest chromosome X resulting in very similar adjusted SCE (SCE(adj)) rates in all categories. Our results - based on 3 independent bulls - show that, although the cattle Y chromosome is a chest full of repeated elements, their presence and the documented activity of repeats in SCE formation does not manifest in significantly higher SCE(adj) rates and suggest the importance of the structural organization of the Y chromosome and the role of alternative mitotic DNA repair mechanisms.

  19. Seismic Fragility Analysis of a Degraded Condensate Storage Tank

    Energy Technology Data Exchange (ETDEWEB)

    Nie, J.; Braverman, J.; Hofmayer, C.; Choun, Y-S.; Kim, M.K.; Choi, I-K.

    2011-05-16

    The Korea Atomic Energy Research Institute (KAERI) and Brookhaven National Laboratory are conducting a collaborative research project to develop seismic capability evaluation technology for degraded structures and components in nuclear power plants (NPPs). One of the goals of this collaboration endeavor is to develop seismic fragility analysis methods that consider the potential effects of age-related degradation of structures, systems, and components (SSCs). The essential part of this collaboration is aimed at achieving a better understanding of the effects of aging on the performance of SSCs and ultimately on the safety of NPPs. A recent search of the degradation occurrences of structures and passive components (SPCs) showed that the rate of aging related degradation in NPPs was not significantly large but increasing, as the plants get older. The slow but increasing rate of degradation of SPCs can potentially affect the safety of the older plants and become an important factor in decision making in the current trend of extending the operating license period of the plants (e.g., in the U.S. from 40 years to 60 years, and even potentially to 80 years). The condition and performance of major aged NPP structures such as the containment contributes to the life span of a plant. A frequent misconception of such low degradation rate of SPCs is that such degradation may not pose significant risk to plant safety. However, under low probability high consequence initiating events, such as large earthquakes, SPCs that have slowly degraded over many years could potentially affect plant safety and these effects need to be better understood. As part of the KAERI-BNL collaboration, a condensate storage tank (CST) was analyzed to estimate its seismic fragility capacities under various postulated degradation scenarios. CSTs were shown to have a significant impact on the seismic core damage frequency of a nuclear power plant. The seismic fragility capacity of the CST was developed

  20. Transfer of small chromosome fragments of Agropyron elongatum to wheat chromosome via asymmetric somatic hybridization

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The chromosome constitution of hybrids and chromatin patterns of Agropyron elongatum(Host)Neviski in F5 somatic hybrid lines Ⅱ -1-3 and I-1-9 between Triticum aestivum L.and A.Elongatum were analyzed.Based on the statistic data of pollen mother cells,F5 I-1-9 and Ⅱ-1-3 had 20-21 bivalents with a frequency of 84.66% and 85.28%,of which,89.83% and 89.57% were ring bivalents.The result indicated that both hybrid lines were basically stable in the chromosome constitution and behavior.RAPD analysis showed that the two hybrids contained biparental and integrated DNA.GISH(Genome in situ hybridization)revealed that in the form of small chromosome segments,A.Elongatum chromatin was scattered on 4-6 wheat chromosomes near by the region of centromere and telomere in the two hybrid lines.SSR analysis indicated that A.Elongatum DNA segments were distributed on the 2A,5B,6B and 2D wheat chromosomes in the hybrids,which was in accordance with the GISH results that small-segments intercalated poly-site.

  1. Chromosome 19 International Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Pericak-Vance, M.A. (Duke Univ., Durham, NC (United States). Medical Center); Ropers, H.H. (Univ. Hospital Nijmegen, (The Netherlands). Dept. of Human Genetics); Carrano, A.J. (Lawrence Livermore National Lab., CA (United States))

    1993-01-04

    The Second International Workshop on Human Chromosome 19 was hosted on January 25 and 26, 1992, by the Department of Human Genetics, University Hospital Nijmegen, The Netherlands, at the 'Meerdal Conference Center'. The workshop was supported by a grant from the European Community obtained through HUGO, the Dutch Research Organization (NWO) and the Muscular Dystrophy Association (MDA). Travel support for American participants was provided by the Department of Energy. The goals of this workshop were to produce genetic, physical and integrated maps of chromosome 19, to identify inconsistencies and gaps, and to discuss and exchange resources and techniques available for the completion of these maps. The second day of the meeting was largely devoted to region or disease specific efforts. In particular, the meeting served as a platform for assessing and discussing the recent progress made into the molecular elucidation of myotonic dystrophy.

  2. Disruption of a conserved CAP-D3 threonine alters condensin loading on mitotic chromosomes leading to chromosome hypercondensation.

    Science.gov (United States)

    Bakhrebah, Muhammed; Zhang, Tao; Mann, Jeff R; Kalitsis, Paul; Hudson, Damien F

    2015-03-06

    The condensin complex plays a key role in organizing mitotic chromosomes. In vertebrates, there are two condensin complexes that have independent and cooperative roles in folding mitotic chromosomes. In this study, we dissect the role of a putative Cdk1 site on the condensin II subunit CAP-D3 in chicken DT40 cells. This conserved site has been shown to activate condensin II during prophase in human cells, and facilitate further phosphorylation by polo-like kinase I. We examined the functional significance of this phosphorylation mark by mutating the orthologous site of CAP-D3 (CAP-D3(T1403A)) in chicken DT40 cells. We show that this mutation is a gain of function mutant in chicken cells; it disrupts prophase, results in a dramatic shortening of the mitotic chromosome axis, and leads to abnormal INCENP localization. Our results imply phosphorylation of CAP-D3 acts to limit condensin II binding onto mitotic chromosomes. We present the first in vivo example that alters the ratio of condensin I:II on mitotic chromosomes. Our results demonstrate this ratio is a critical determinant in shaping mitotic chromosomes.

  3. Characterization, treatment patterns, and patient-related outcomes of patients with Fragile X syndrome in Germany: final results of the observational EXPLAIN-FXS study

    OpenAIRE

    2016-01-01

    Background As data on the phenotype, characteristics and management of patients with Fragile X Syndrome (FXS) are limited, we aimed to collect such data in Germany in experienced centres involved in the treatment of such patients. Methods EXPLAIN-FXS is a prospective observational (non-interventional) study (registry) performed between April 2013 and January 2016 at 18 sites in Germany. Requirements for patient participation included confirmed diagnosis of FXS by genetic testing (>200 CGG rep...

  4. Multiple opposing constraints govern chromosome interactions during meiosis.

    Directory of Open Access Journals (Sweden)

    Doris Y Lui

    Full Text Available Homolog pairing and crossing over during meiosis I prophase is required for accurate chromosome segregation to form euploid gametes. The repair of Spo11-induced double-strand breaks (DSB using a homologous chromosome template is a major driver of pairing in many species, including fungi, plants, and mammals. Inappropriate pairing and crossing over at ectopic loci can lead to chromosome rearrangements and aneuploidy. How (or if inappropriate ectopic interactions are disrupted in favor of allelic interactions is not clear. Here we used an in vivo "collision" assay in budding yeast to test the contributions of cohesion and the organization and motion of chromosomes in the nucleus on promoting or antagonizing interactions between allelic and ectopic loci at interstitial chromosome sites. We found that deletion of the cohesin subunit Rec8, but not other chromosome axis proteins (e.g. Red1, Hop1, or Mek1, caused an increase in homolog-nonspecific chromosome interaction, even in the absence of Spo11. This effect was partially suppressed by expression of the mitotic cohesin paralog Scc1/Mdc1, implicating Rec8's role in cohesion rather than axis integrity in preventing nonspecific chromosome interactions. Disruption of telomere-led motion by treating cells with the actin polymerization inhibitor Latrunculin B (Lat B elevated nonspecific collisions in rec8Δ spo11Δ. Next, using a visual homolog-pairing assay, we found that the delay in homolog pairing in mutants defective for telomere-led chromosome motion (ndj1Δ or csm4Δ is enhanced in Lat B-treated cells, implicating actin in more than one process promoting homolog juxtaposition. We suggest that multiple, independent contributions of actin, cohesin, and telomere function are integrated to promote stable homolog-specific interactions and to destabilize weak nonspecific interactions by modulating the elastic spring-like properties of chromosomes.

  5. Evidence for a Xer/dif system for chromosome resolution in archaea.

    Directory of Open Access Journals (Sweden)

    Diego Cortez

    2010-10-01

    Full Text Available Homologous recombination events between circular chromosomes, occurring during or after replication, can generate dimers that need to be converted to monomers prior to their segregation at cell division. In Escherichia coli, chromosome dimers are converted to monomers by two paralogous site-specific tyrosine recombinases of the Xer family (XerC/D. The Xer recombinases act at a specific dif site located in the replication termination region, assisted by the cell division protein FtsK. This chromosome resolution system has been predicted in most Bacteria and further characterized for some species. Archaea have circular chromosomes and an active homologous recombination system and should therefore resolve chromosome dimers. Most archaea harbour a single homologue of bacterial XerC/D proteins (XerA, but not of FtsK. Therefore, the role of XerA in chromosome resolution was unclear. Here, we have identified dif-like sites in archaeal genomes by using a combination of modeling and comparative genomics approaches. These sites are systematically located in replication termination regions. We validated our in silico prediction by showing that the XerA protein of Pyrococcus abyssi specifically recombines plasmids containing the predicted dif site in vitro. In contrast to the bacterial system, XerA can recombine dif sites in the absence of protein partners. Whereas Archaea and Bacteria use a completely different set of proteins for chromosome replication, our data strongly suggest that XerA is most likely used for chromosome resolution in Archaea.

  6. DNA testing for fragile X syndrome: implications for parents and family.

    OpenAIRE

    van Rijn, M A; de Vries, B B; Tibben, A; van den Ouweland, A M; Halley, D J; Niermeijer, M F

    1997-01-01

    The fragile X syndrome is an X linked, semidominant mental retardation disorder caused by the amplification of a CGG repeat in the 5' UTR of the FMR1 gene. Nineteen fragile X families in which the mutated FMR1 gene segregated were evaluated. The implications of the diagnosis for the parents and family were studied through pedigree information, interviews, and questionnaires. Information about the heredity of fragile X syndrome was only disseminated by family members to a third (124/366) of th...

  7. Beyond the Factor of Safety: Developing Fragility Curves to Characterize System Reliability

    Science.gov (United States)

    2010-07-01

    hysteretic devices. Computers and Structures 86: 1769–1781. Celik, O. C., and B. R. Ellingwood. 2008. Modeling beam- column joints in fragility...fragility curves for reinforced concrete frame structures using an empirical model of the shear and bond- slip behavior of beam column joints exposed...southeastern United States. Fragility curves were developed for five components of each bridge type ( columns , steel bearings, expansion bearings, fixed

  8. Phosphorylation of chromosome core components may serve as axis marks for the status of chromosomal events during mammalian meiosis.

    Directory of Open Access Journals (Sweden)

    Tomoyuki Fukuda

    2012-02-01

    Full Text Available Meiotic recombination and chromosome synapsis between homologous chromosomes are essential for proper chromosome segregation at the first meiotic division. While recombination and synapsis, as well as checkpoints that monitor these two events, take place in the context of a prophase I-specific axial chromosome structure, it remains unclear how chromosome axis components contribute to these processes. We show here that many protein components of the meiotic chromosome axis, including SYCP2, SYCP3, HORMAD1, HORMAD2, SMC3, STAG3, and REC8, become post-translationally modified by phosphorylation during the prophase I stage. We found that HORMAD1 and SMC3 are phosphorylated at a consensus site for the ATM/ATR checkpoint kinase and that the phosphorylated forms of HORMAD1 and SMC3 localize preferentially to unsynapsed chromosomal regions where synapsis has not yet occurred, but not to synapsed or desynapsed regions. We investigated the genetic requirements for the phosphorylation events and revealed that the phosphorylation levels of HORMAD1, HORMAD2, and SMC3 are dramatically reduced in the absence of initiation of meiotic recombination, whereas BRCA1 and SYCP3 are required for normal levels of phosphorylation of HORMAD1 and HORMAD2, but not of SMC3. Interestingly, reduced HORMAD1 and HORMAD2 phosphorylation is associated with impaired targeting of the MSUC (meiotic silencing of unsynapsed chromatin machinery to unsynapsed chromosomes, suggesting that these post-translational events contribute to the regulation of the synapsis surveillance system. We propose that modifications of chromosome axis components serve as signals that facilitate chromosomal events including recombination, checkpoint control, transcription, and synapsis regulation.

  9. Thermodynamics and fragility of glass-forming alloys

    Energy Technology Data Exchange (ETDEWEB)

    Battezzati, L., E-mail: livio.battezzati@unito.it [Dipartimento di Chimica e Centro NIS, Università di Torino, Via P. Giuria 7, 10125 Torino (Italy); Dalla Fontana, G. [Dipartimento di Chimica e Centro NIS, Università di Torino, Via P. Giuria 7, 10125 Torino (Italy)

    2014-02-15

    Highlights: ► Thermodynamic and dynamic properties of metallic melts compared with those of other glass formers. ► Relationships between ΔS{sub g}/ΔC{sub p,g} and relevant temperatures for the glass demonstrated. ► Correspondence with either hyperbolic or Gaussian distribution of the states in the PEL shown. ► Correlations allow estimate of unknown quantities and pinpoint peculiar behavior of liquid. -- Abstract: The existing correlation between the extensive properties, ΔH and ΔS, the enthalpy and entropy difference between liquid and crystal phases has been checked to relate metallic glasses to other classes of amorphous materials. Expressing the specific heat difference, ΔC{sub p}, of molten and crystalline metallic glass-formers as a function of temperature with different functional trends, parametric expressions of fragility are derived using relevant temperatures for alloys. It is shown that relationships between the ΔS{sub g}/ΔC{sub p,g} ratio and such temperatures are useful to estimate unknown quantities when the experimental determination of the specific heat is possible. Thermodynamic indicators of fragility are compared to the kinetic fragility obtained from viscosity data accounting for the estimated errors on parameters which are derived from extrapolations. The outcome of the analysis indicates that a relationship between thermodynamic and kinetic parameters exists. Moreover a systematic scatter for some alloys indicates a diverse behavior which can be ascribed to structure modification either in the liquid or in the solid reference state.

  10. Kinetics of the glass transition of fragile soft colloidal suspensions

    Science.gov (United States)

    Saha, Debasish; Joshi, Yogesh M.; Bandyopadhyay, Ranjini

    2015-12-01

    Microscopic relaxation time scales are estimated from the autocorrelation functions obtained by dynamic light scattering experiments for Laponite suspensions with different concentrations (CL), added salt concentrations (CS), and temperatures (T). It has been shown in an earlier work [D. Saha, Y. M. Joshi, and R. Bandyopadhyay, Soft Matter 10, 3292 (2014)] that the evolutions of relaxation time scales of colloidal glasses can be compared with molecular glass formers by mapping the waiting time (tw) of the former with the inverse of thermodynamic temperature (1/T) of the latter. In this work, the fragility parameter D, which signifies the deviation from Arrhenius behavior, is obtained from fits to the time evolutions of the structural relaxation time scales. For the Laponite suspensions studied in this work, D is seen to be independent of CL and CS but is weakly dependent on T. Interestingly, the behavior of D corroborates the behavior of fragility in molecular glass formers with respect to equivalent variables. Furthermore, the stretching exponent β, which quantifies the width w of the spectrum of structural relaxation time scales, is seen to depend on tw. A hypothetical Kauzmann time tk, analogous to the Kauzmann temperature for molecular glasses, is defined as the time scale at which w diverges. Corresponding to the Vogel temperature defined for molecular glasses, a hypothetical Vogel time tα ∞ is also defined as the time at which the structural relaxation time diverges. Interestingly, a correlation is observed between tk and tα ∞ , which is remarkably similar to that known for fragile molecular glass formers. A coupling model that accounts for the tw-dependence of the stretching exponent is used to analyse and explain the observed correlation between tk and tα ∞ .

  11. A simplified fragility analysis of fan type cable stayed bridges

    Institute of Scientific and Technical Information of China (English)

    R. A. Khan; T. K. Datta; S. Ahmad

    2005-01-01

    A simplified fragility analysis of fan type cable stayed bridges using Probabilistic Risk Analysis (PRA)procedure is presented for determining their failure probability under random ground motion. Seismic input to the bridge support is considered to be a risk consistent response spectrum which is obtained from a separate analysis. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of cable-tower-deck system. The analysis provides a coupled stiffness matrix for the spring system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges .The response of the bridge deck is obtained by the response spectrum method of analysis as applied to multidegree of freedom system which duly takes into account the quasi - static component of bridge deck vibration. The fragility analysis includes uncertainties arising due to the variation in ground motion, material property, modeling, method of analysis,ductility factor and damage concentration effect. Probability of failure of the bridge deck is determined by the First Order Second Moment (FOSM) method of reliability. A three span double plane symmetrical fan type cable stayed bridge of total span 689 m, is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations. Some of the important conclusions of the study indicate that (i) not only vertical component but also the horizontal component of ground motion has considerable effect on the probability of failure; (ii) ground motion with no time lag between support excitations provides a smaller probability of failure as compared to ground motion with very large time lag between support excitation; and (iii) probability of failure may considerably increase for soft soil condition.

  12. A dynamic, mitotic-like mechanism for bacterial chromosome segregation.

    Science.gov (United States)

    Fogel, Michael A; Waldor, Matthew K

    2006-12-01

    The mechanisms that mediate chromosome segregation in bacteria are poorly understood. Despite evidence of dynamic movement of chromosome regions, to date, mitotic-like mechanisms that act on the bacterial chromosome have not been demonstrated. Here we provide evidence that the Vibrio cholerae ParAI and ParBI proteins are components of an apparatus that pulls the origin region of the large V. cholerae chromosome to the cell pole and anchors it there. ParBI interacts with a conserved origin-proximal, centromere-like site (parSI) that, following chromosome replication, segregates asymmetrically from one pole to the other. While segregating, parSI stretches far away from neighboring chromosomal loci. ParAI forms a dynamic band that extends from the pole to the segregating ParBI/parSI complex. Movement of ParBI/parSI across the cell occurs in concert with ParAI retraction. Deletion of parAI disrupts proper origin localization and segregation dynamics, and parSI no longer separates from nearby regions. These data suggest that ParAI forms a dynamic structure that pulls the ParBI-bound chromosome to the pole in a process analogous to anaphase of eukaryotic mitosis.

  13. Circular permutation of a synthetic eukaryotic chromosome with the telomerator

    Science.gov (United States)

    Mitchell, Leslie A.; Boeke, Jef D.

    2014-01-01

    Chromosome engineering is a major focus in the fields of systems biology, genetics, synthetic biology, and the functional analysis of genomes. Here, we describe the “telomerator,” a new synthetic biology device for use in Saccharomyces cerevisiae. The telomerator is designed to inducibly convert circular DNA molecules into mitotically stable, linear chromosomes replete with functional telomeres in vivo. The telomerator cassette encodes convergent yeast telomere seed sequences flanking the I-SceI homing endonuclease recognition site in the center of an intron artificially transplanted into the URA3 selectable/counterselectable auxotrophic marker. We show that inducible expression of the homing endonuclease efficiently generates linear molecules, identified by using a simple plate-based screening method. To showcase its functionality and utility, we use the telomerator to circularly permute a synthetic yeast chromosome originally constructed as a circular molecule, synIXR, to generate 51 linear variants. Many of the derived linear chromosomes confer unexpected phenotypic properties. This finding indicates that the telomerator offers a new way to study the effects of gene placement on chromosomes (i.e., telomere proximity). However, that the majority of synIXR linear derivatives support viability highlights inherent tolerance of S. cerevisiae to changes in gene order and overall chromosome structure. The telomerator serves as an important tool to construct artificial linear chromosomes in yeast; the concept can be extended to other eukaryotes. PMID:25378705

  14. Intestinl fragility during ochratoxicosis and aflatoxicosis in broiler chickens.

    OpenAIRE

    1980-01-01

    Graded concentrations of dietary ochratoxin (0, 0.5, 1.0, 2.0, 4.0, and 8.0 microgram/g) and aflatoxin (0, 0.625, 1.25, 2.5, 5.0, and 10.0 microgram/g) were fed to broiler chicks from hatching to 3 weeks of age. The breaking strength of the large intestines was decreased significantly (P < 0.05) by ochratoxin (2, 4, and 8 microgram/g), but not by aflatoxin. This fragility was accompanied by an increase in the weight of the large intestine relative to body weight of birds fed ochratoxin (4.0 a...

  15. [The usefulness of protective creams on fragile and aged skin].

    Science.gov (United States)

    Rueda López, Justo; Guerrero Palmero, Alberto; Muñoz Bueno, Ana Maria; Esquius i Carbonell, Jacint; Rosell Moreno, Carmen

    2005-06-01

    The ADDERMIS protective cream has these properties: it prevents skin maceration, exercises a regenerative effect, has bacteriostatic and bactericide activity, possesses a noted anti-inflammatory effect and reduces the risk of mycotic infections. Its application is indicated for use in cases of: skin lesions, such as bed sores or leg ulcers, which require the use of a barrier product; dermatitis lesions in zones of skin folds or due to diaper use; to prevent friction zones; fragile skin; peeling, zones where cracks in the skin appear...and to use for cases of incontinence when diapers are required.

  16. WATERMARKING AUTHENTICATION: USING THE FRAGILE MODE OR THE ROBUST MODE?

    Institute of Scientific and Technical Information of China (English)

    Chen Dan; Wu Qianhong; Wang Yumin

    2006-01-01

    Due to the lack of a unified authentication model certain mistakes occurred in the use of the watermarking authentication methods. To clarify the confusion, authentication models of robust and fragile watermarking are developed respectively in the paper. Concrete algorithms are proposed to prove the models that different Discrete Wavelet Transform (DWT) domains are utilized to embed the watermarks and quantization method is presented with Just Notice Differences (JNDs) threshold as the quantization size. After the key technologies about the two methods are discussed, we detail the comparison of the two modes and recommend their respective application scenarios as applicable results.

  17. A new semi-fragile watermarking algorithm for image authentication

    Institute of Scientific and Technical Information of China (English)

    HAN De-zhi; HU Yu-ping

    2005-01-01

    This paper presents a new semi-fragile watermarking algorithm for image authentication which extracts image features from the low frequency domain to generate two watermarks: one for classifying of the intentional content modification and the other for indicating the modified location. The algorithm provides an effective mechanism for image authentication. The watermark generation and watermark embedment are disposed in the image itself, and the received image authentication needs no information about the original image or watermark. The algorithm increases watermark security and prevents forged watermark. Experimental results show that the algorithm can identify intentional content modification and incidental tampering, and also indicate the location where a modification takes place.

  18. Emerging pharmacologic treatment options for fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Schaefer TL

    2015-04-01

    Full Text Available Tori L Schaefer, Matthew H Davenport, Craig A Erickson Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA Abstract: Fragile X syndrome (FXS is the most common single gene cause of intellectual disability and autism spectrum disorder. Caused by a silenced fragile X mental retardation 1 gene and the subsequent deficiency in fragile X mental retardation protein, patients with FXS experience a range of physical, behavioral, and intellectual debilitations. The FXS field, as a whole, has recently met with some challenges, as several targeted clinical trials with high expectations of success have failed to elucidate significant improvements in a variety of symptom domains. As new clinical trials in FXS are planned, there has been much discussion about the use of the commonly used clinical outcome measures, as well as study design considerations, patient stratification, and optimal age range for treatment. The evidence that modification of these drug targets and use of these failed compounds would prove to be efficacious in human clinical study were rooted in years of basic and translational research. There are questions arising as to the use of the mouse models for studying FXS treatment development. This issue is twofold: many of the symptom domains and molecular and biochemical changes assessed and indicative of efficacy in mouse model study are not easily amenable to clinical trials in people with FXS because of the intolerability of the testing paradigm or a lack of noninvasive techniques (prepulse inhibition, sensory hypersensitivity, startle reactivity, or electrophysiologic, biochemical, or structural changes in the brain; and capturing subtle yet meaningful changes in symptom domains such as sociability, anxiety, and hyperactivity in human FXS clinical trials is challenging with the currently used measures (typically parent/caregiver rating scales. Clinicians, researchers, and the

  19. Detect Image Tamper by Semi-Fragile Digital Watermarking

    Institute of Scientific and Technical Information of China (English)

    LIUFeilong; WANGYangsheng

    2004-01-01

    To authenticate the integrity of image while resisting some valid image processing such as JPEG compression, a semi-fragile image watermarking is described. Image name, one of the image features, has been used as the key of pseudo-random function to generate the special watermarks for the different image. Watermarks are embedded by changing the relationship between the blocks' DCT DC coefficients, and the image tamper are detected with the relationship of these DCT DC coefficients.Experimental results show that the proposed technique can resist JPEG compression, and detect image tamper in the meantime.

  20. Fourth international workshop on human chromosome 5. Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, J.D.

    1996-12-31

    The Fourth International Workshop on Human Chromosome 5 was held in Manchester, UK on November 9--10, 1996 and was hosted by the University of Manchester. The major goals of the workshop were: (1) to collate the various genetic, cytogenetic and physical maps of human chromosome 5; (2) to integrate these maps and identify/correct discrepancies between them wherever possible; (3) to catalogue the sequence-ready contigs of the chromosome; (4) to co-ordinate the various sequencing efforts to avoid future duplication; (5) to establish the first (to the author`s knowledge) web site for the human chromosome 5 community which contains the above information in a readily accessible form.

  1. Role of ATRX in chromatin structure and function: implications for chromosome instability and human disease.

    Science.gov (United States)

    De La Fuente, Rabindranath; Baumann, Claudia; Viveiros, Maria M

    2011-08-01

    Functional differentiation of chromatin structure is essential for the control of gene expression, nuclear architecture, and chromosome stability. Compelling evidence indicates that alterations in chromatin remodeling proteins play an important role in the pathogenesis of human disease. Among these, α-thalassemia mental retardation X-linked protein (ATRX) has recently emerged as a critical factor involved in heterochromatin formation at mammalian centromeres and telomeres as well as facultative heterochromatin on the murine inactive X chromosome. Mutations in human ATRX result in an X-linked neurodevelopmental condition with various degrees of gonadal dysgenesis (ATRX syndrome). Patients with ATRX syndrome may exhibit skewed X chromosome inactivation (XCI) patterns, and ATRX-deficient mice exhibit abnormal imprinted XCI in the trophoblast cell line. Non-random or skewed XCI can potentially affect both the onset and severity of X-linked disease. Notably, failure to establish epigenetic modifications associated with the inactive X chromosome (Xi) results in several conditions that exhibit genomic and chromosome instability such as fragile X syndrome as well as cancer development. Insight into the molecular mechanisms of ATRX function and its interacting partners in different tissues will no doubt contribute to our understanding of the pathogenesis of ATRX syndrome as well as the epigenetic origins of aneuploidy. In turn, this knowledge will be essential for the identification of novel drug targets and diagnostic tools for cancer progression as well as the therapeutic management of global epigenetic changes commonly associated with malignant neoplastic transformation.

  2. 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.

  3. Chromosome assortment in Saccharum.

    Science.gov (United States)

    Al-Janabi, S M; Honeycutt, R J; Sobral, B W

    1994-12-01

    Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum 'SES 208' and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum 'LA Purple' and Saccharum robustum ' Mol 5829'. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.

  4. Structural organization of the inactive X chromosome in the mouse.

    Science.gov (United States)

    Giorgetti, Luca; Lajoie, Bryan R; Carter, Ava C; Attia, Mikael; Zhan, Ye; Xu, Jin; Chen, Chong Jian; Kaplan, Noam; Chang, Howard Y; Heard, Edith; Dekker, Job

    2016-07-28

    X-chromosome inactivation (XCI) involves major reorganization of the X chromosome as it becomes silent and heterochromatic. During female mammalian development, XCI is triggered by upregulation of the non-coding Xist RNA from one of the two X chromosomes. Xist coats the chromosome in cis and induces silencing of almost all genes via its A-repeat region, although some genes (constitutive escapees) avoid silencing in most cell types, and others (facultative escapees) escape XCI only in specific contexts. A role for Xist in organizing the inactive X (Xi) chromosome has been proposed. Recent chromosome conformation capture approaches have revealed global loss of local structure on the Xi chromosome and formation of large mega-domains, separated by a region containing the DXZ4 macrosatellite. However, the molecular architecture of the Xi chromosome, in both the silent and expressed regions,remains unclear. Here we investigate the structure, chromatin accessibility and expression status of the mouse Xi chromosome in highly polymorphic clonal neural progenitors (NPCs) and embryonic stem cells. We demonstrate a crucial role for Xist and the DXZ4-containing boundary in shaping Xi chromosome structure using allele-specific genome-wide chromosome conformation capture (Hi-C) analysis, an assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) and RNA sequencing. Deletion of the boundary disrupts mega-domain formation, and induction of Xist RNA initiates formation of the boundary and the loss of DNA accessibility. We also show that in NPCs, the Xi chromosome lacks active/inactive compartments and topologically associating domains (TADs), except around genes that escape XCI. Escapee gene clusters display TAD-like structures and retain DNA accessibility at promoter-proximal and CTCF-binding sites. Furthermore, altered patterns of facultative escape genes indifferent neural progenitor clones are associated with the presence of different TAD

  5. Neurological and endocrine phenotypes of fragile X carrier women.

    Science.gov (United States)

    Hall, D; Todorova-Koteva, K; Pandya, S; Bernard, B; Ouyang, B; Walsh, M; Pounardjian, T; Deburghraeve, C; Zhou, L; Losh, M; Leehey, M; Berry-Kravis, E

    2016-01-01

    Women who carry fragile X mental retardation 1 (FMR1)gene premutation expansions frequently report neurological or endocrine symptoms and prior studies have predominantly focused on questionnaire report of medical issues. Premutation carrier (PMC) women (n = 33) and non-carrier controls (n = 13) were recruited and evaluated by a neurologist, neuropsychologist, and endocrinologist. Blood and skin biopsies were collected for molecular measures. Scales for movement disorders, neuropathy, cognitive function, psychiatric symptoms, sleep, and quality of life were completed. The average age of the women was 51 years (n = 46) and average CGG repeat size was 91 ± 24.9 in the FMR1 PMC women. Seventy percent of the PMC women had an abnormal neurological examination. PMC women had significantly higher scores on the Fragile X-Associated Tremor Ataxia Syndrome (FXTAS) rating scale, more neuropathy, and difficulty with tandem gait compared to controls. Central sensitivity syndromes, a neuroticism profile on the NEO Personality Profile, and sleep disorders were also prevalent. Discrepancies between subject report and examination findings were also seen. This pilot study suggests that women with the FMR1 premutation may have a phenotype that overlaps with that seen in FXTAS. Additional research with larger sample sizes is warranted to better delineate the clinical features.

  6. Evaluation of Seismic Fragility of Weir Structures in South Korea

    Directory of Open Access Journals (Sweden)

    Bu Seog Ju

    2015-01-01

    Full Text Available In order to reduce earthquake damage of multifunctional weir systems similar to a dam structure, this study focused on probabilistic seismic risk assessment of the weir structure using the fragility methodology based on Monte Carlo simulation (MCS, with emphasis on the uncertainties of the seismic ground motions in terms of near field induced pulse-like motions and far field faults. The 2D simple linear elastic plain strain finite element (FE model including soil structure foundations using tie connection method in ABAQUS was developed to incorporate the uncertainty. In addition, five different limit states as safety criteria were defined for the seismic vulnerability of the weir system. As a consequence, the results obtained from multiple linear time history analyses revealed that the weir structure was more vulnerable to the tensile stress of the mass concrete in both near and far field ground motions specified earthquake hazard levels. In addition, the system subjected to near field motions was primarily more fragile than that under far field ground motions. On the other hand, the probability of failure due to the tensile stress at weir sill and stilling basin showed the similar trend in the overall peak ground acceleration levels.

  7. Tunnelling through weak and fragile rocks of Himalayas

    Institute of Scientific and Technical Information of China (English)

    Goel R.K.

    2014-01-01

    A considerable amount of tunnelling has been going on in India for various projects such as hydroelectric power, irrigation, roads and railways. Most of these projects are located in Himalayas, far away from the urban areas. Tunnelling through weak and jointed rock masses such as the one in the Himalayas is a challenging task for the planners, designers, engineers and geologists because of high overburden, thickly vegetated surface, weak, poor and fragile rocks and highly varying geology with the presence of numerous small and big shear zones, faults, etc. Due to these reasons, various tunnelling problems have been faced in the past and are still being encountered. Failures and the problems may be regarded as challenges and opportunities for generating new knowledge base and thereby increasing self-reliance in tunnelling. The experiences of Himalayan tunnelling through weak and fragile rocks covering varying and mixed geology, understanding on tunnelling in squeezing ground conditions and applicability of TBM in Himalayas are presented. It has also been highlighted that the probe holes planning, drilling and mon-itoring shall be followed seriously to reduce the geological surprises.

  8. Profiles of aberrant white matter microstructure in fragile X syndrome.

    Science.gov (United States)

    Hall, Scott S; Dougherty, Robert F; Reiss, Allan L

    2016-01-01

    Previous studies attempting to quantify white matter (WM) microstructure in individuals with fragile X syndrome (FXS) have produced inconsistent findings, most likely due to the various control groups employed, differing analysis methods, and failure to examine for potential motion artifact. In addition, analyses have heretofore lacked sufficient specificity to provide regional information. In this study, we used Automated Fiber-tract Quantification (AFQ) to identify specific regions of aberrant WM microstructure along WM tracts in patients with FXS that differed from controls who were matched on age, IQ and degree of autistic symptoms. Participants were 20 patients with FXS, aged 10 to 23 years, and 20 matched controls. Using Automated Fiber-tract Quantification (AFQ), we created Tract Profiles of fractional anisotropy and mean diffusivity along 18 major WM fascicles. We found that fractional anisotropy was significantly increased in the left and right inferior longitudinal fasciculus (ILF), right uncinate fasciculus, and left cingulum hippocampus in individuals with FXS compared to controls. Conversely, mean diffusivity was significantly decreased in the right ILF in patients with FXS compared to controls. Age was significantly negatively associated with MD values across both groups in 11 tracts. Taken together, these findings indicate that FXS results in abnormal WM microstructure in specific regions of the ILF and uncinate fasciculus, most likely caused by inefficient synaptic pruning as a result of decreased or absent Fragile X Mental Retardation Protein (FMRP). Longitudinal studies are needed to confirm these findings.

  9. Profiles of aberrant white matter microstructure in fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Scott S. Hall

    2016-01-01

    Full Text Available Previous studies attempting to quantify white matter (WM microstructure in individuals with fragile X syndrome (FXS have produced inconsistent findings, most likely due to the various control groups employed, differing analysis methods, and failure to examine for potential motion artifact. In addition, analyses have heretofore lacked sufficient specificity to provide regional information. In this study, we used Automated Fiber-tract Quantification (AFQ to identify specific regions of aberrant WM microstructure along WM tracts in patients with FXS that differed from controls who were matched on age, IQ and degree of autistic symptoms. Participants were 20 patients with FXS, aged 10 to 23 years, and 20 matched controls. Using Automated Fiber-tract Quantification (AFQ, we created Tract Profiles of fractional anisotropy and mean diffusivity along 18 major WM fascicles. We found that fractional anisotropy was significantly increased in the left and right inferior longitudinal fasciculus (ILF, right uncinate fasciculus, and left cingulum hippocampus in individuals with FXS compared to controls. Conversely, mean diffusivity was significantly decreased in the right ILF in patients with FXS compared to controls. Age was significantly negatively associated with MD values across both groups in 11 tracts. Taken together, these findings indicate that FXS results in abnormal WM microstructure in specific regions of the ILF and uncinate fasciculus, most likely caused by inefficient synaptic pruning as a result of decreased or absent Fragile X Mental Retardation Protein (FMRP. Longitudinal studies are needed to confirm these findings.

  10. Fragile X syndrome: Are signaling lipids the missing culprits?

    Science.gov (United States)

    Tabet, Ricardos; Vitale, Nicolas; Moine, Hervé

    2016-11-01

    Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and autism. FXS results from the absence of FMRP, an RNA binding protein associated to ribosomes that influences the translation of specific mRNAs in post-synaptic compartments of neurons. The main molecular consequence of the absence of FMRP is an excessive translation of neuronal protein in several areas of the brain. This local protein synthesis deregulation is proposed to underlie the defect in synaptic plasticity responsible for FXS. Recent findings in neurons of the fragile X mouse model (Fmr1-KO) uncovered another consequence of the lack of FMRP: a deregulation of the diacylglycerol (DAG)/phosphatidic acid (PA) homeostasis. DAG and PA are two interconvertible lipids that influence membrane architecture and that act as essential signaling molecules that activate various downstream effectors, including master regulators of local protein synthesis and actin polymerization. As a consequence, DAG and PA govern a variety of cellular processes, including cell proliferation, vesicle/membrane trafficking and cytoskeletal organization. At the synapse, the level of these lipids is proposed to influence the synaptic activation status. FMRP appears as a master regulator of this neuronal process by controlling the translation of a diacylglycerol kinase enzyme that converts DAG into PA. The deregulated levels of DAG and PA caused by the absence of FMRP could represent a novel therapeutic target for the treatment of FXS.

  11. Loss of fragile histidine triad protein in human hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Po Zhao; Xin Song; Yuan-Yuan Nin; Ya-Li Lu; Xiang-Hong Li

    2003-01-01

    AIM: To investigate the expression of fragile histidine triad (FHIT) gene protein, Fhit, which is recently thought to be a candidate tumor suppressor. Abnormal expression of fragile histidine triad has been found in a variety of human cancers,but little is known about its expression in human hepatocellular carcinogenesis and evolution.METHODS: Sections of 83 primary human hepatocellular carcionoma with corresponding para-neoplastic liver tissue and 10 normal liver tissue were evaluated immunohistochemically for Fhit protein expression.RESULTS: All normal liver tissue and para-neoplastic liver tissue showed a strong expression of Fhit, whereas 50 of 83(65.0 %) carcinomas showed a marked loss or absence of Fhit expression. The differences of Fhit expression between carcinoma and normal or para-neoplastic liver tissue werehighly significant (P=0.000). The proportion of carcinomas with reduced Fhit expression showed an increasing trend (a) with decreasing differentiation or higher histological grade (P=0.219); (b) in tumors with higher clinical stage Ⅲ and ⅣV (91.3 %, P=0.000), compared with tumors with lower stage Ⅰ and Ⅱ (27.6 %); and (c) in cancers with bigger tumor size (>50 mm) (75.0 %, P=0.017), compared withsmaller tumor size (≤ 50 mm). CONCLUSION: FHIT inactivation seems to be both an earlyand a later event, associated with carcinogenesis andprogression to more aggressive hepatocellular carcinomas.Thus, evaluation of Fhit expression by immunohistochemistryin hepatocellular carcinoma may provide important diagnosticand prognostic information in clinical application.

  12. Dementia in Fragile X-associated Tremor/Ataxia Syndrome

    Directory of Open Access Journals (Sweden)

    Ricardo Nitrini

    Full Text Available Abstract Fragile X-associated tremor/ataxia syndrome (FXTAS is a cause of movement disorders and cognitive decline which has probably been underdiagnosed, especially if its prevalence proves similar to those of progressive supranuclear palsy and amyotrophic lateral sclerosis. We report a case of a 74-year-old man who presented with action tremor, gait ataxia and forgetfulness. There was a family history of tremor and dementia, and one of the patient's grandsons was mentally deficient. Neuropsychological evaluation disclosed a frontal network syndrome. MRI showed hyperintensity of both middle cerebellar peduncles, a major diagnostic hallmark of FXTAS. Genetic testing revealed premutation of the FMR1 gene with an expanded (CGG90 repeat. The diagnosis of FXTAS is important for genetic counseling because the daughters of the affected individuals are at high risk of having offspring with fragile X syndrome. Tremors and cognitive decline should raise the diagnostic hypothesis of FXTAS, which MRI may subsequently reinforce, while the detection of the FMR1 premutation can confirm the condition.

  13. In vivo brain anatomy of adult males with Fragile X syndrome: an MRI study.

    LENUS (Irish Health Repository)

    Hallahan, Brian P

    2011-01-01

    Fragile X Syndrome (FraX) is caused by the expansion of a single trinucleotide gene sequence (CGG) on the X chromosome, and is a leading cause of learning disability (mental retardation) worldwide. Relatively few studies, however, have examined the neuroanatomical abnormalities associated with FraX. Of those that are available many included mixed gender populations, combined FraX children and adults into one sample, and employed manual tracing techniques which measures bulk volume of particular regions. Hence, there is relatively little information on differences in grey and white matter content across whole brain. We employed magnetic resonance imaging to investigate brain anatomy in 17 adult males with FraX and 18 healthy controls that did not differ significantly in age. Data were analysed using stereology and VBM to compare (respectively) regional brain bulk volume, and localised grey\\/white matter content. Using stereology we found that FraX males had a significant increase in bulk volume bilaterally of the caudate nucleus and parietal lobes and of the right brainstem, but a significant decrease in volume of the left frontal lobe. Our complimentary VBM analysis revealed an increased volume of grey matter in fronto-striatal regions (including bilaterally in the caudate nucleus), and increased white matter in regions extending from the brainstem to the parahippocampal gyrus, and from the left cingulate cortex extending into the corpus callosum. People with FraX have regionally specific differences in brain anatomy from healthy controls with enlargement of the caudate nuclei that persists into adulthood.

  14. 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…

  15. Chromosomal rearrangement interferes with meiotic X chromosome inactivation.

    Science.gov (United States)

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-10-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X-autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencing of unsynapsed chromatin (MSUC). Here, we report on the transcriptional down-regulation of genes within the unsynapsed region of the rearranged mouse chromosome 17, and on the subsequent disturbance of X chromosome inactivation. The partial transcriptional suppression of genes in the unsynapsed chromatin was most prominent prior to the mid-pachytene stage of primary spermatocytes. Later, during the mid-late pachytene, the rearranged autosomes colocalized with the XY body, and the X chromosome failed to undergo proper transcriptional silencing. Our findings provide direct evidence on the MSUC acting at the mRNA level, and implicate that autosomal asynapsis in meiosis may cause male sterility by interfering with meiotic sex chromosome inactivation.

  16. The r1162 mob proteins can promote conjugative transfer from cryptic origins in the bacterial chromosome.

    Science.gov (United States)

    Meyer, Richard

    2009-03-01

    The mobilization proteins of the broad-host-range plasmid R1162 can initiate conjugative transfer of a plasmid from a 19-bp locus that is partially degenerate in sequence. Such loci are likely to appear by chance in the bacterial chromosome and could act as cryptic sites for transfer of chromosomal DNA when R1162 is present. The R1162-dependent transfer of chromosomal DNA, initiated from one such potential site in Pectobacterium atrosepticum, is shown here. A second active site was identified in Escherichia coli, where it is also shown that large amounts of DNA are transferred. This transfer probably reflects the combined activity of the multiple cryptic origins in the chromosome. Transfer of chromosomal DNA due to the presence of a plasmid in the cytoplasm describes a previously unrecognized potential for the exchange of bacterial DNA.

  17. Delineating the Profile of Autism Spectrum Disorder Characteristics in Cornelia de Lange and Fragile X Syndromes

    Science.gov (United States)

    Moss, Joanna; Oliver, Chris; Nelson, Lisa; Richards, Caroline; Hall, Scott

    2013-01-01

    An atypical presentation of autism spectrum disorder is noted in Cornelia de Lange and Fragile X syndromes, but there are few detailed empirical descriptions. Participants in this study were individuals with Cornelia de Lange syndrome (n = 130, M age = 17.19), Fragile X syndrome (n = 182, M age = 16.94), and autism spectrum disorder (n = 142, M…

  18. Public private cooperation fragile states: Report on field research mission to North Kivu and Ituri

    NARCIS (Netherlands)

    Douma, P.; Bolhuis, E.E.; Klaver, D.C.; Zawadi, Y.

    2009-01-01

    This field study is part of the Schokland project to research among others the possibilities for Public Private Cooperation (PPC) in stimulating Economic Growth in Fragile States. Fragile states are relatively far behind in achieving the Millennium Development Goals (MDGs) and in order to reduce fra

  19. Between Development and Security: The European Union, Governance and Fragile States

    NARCIS (Netherlands)

    W. Hout (Wil)

    2009-01-01

    textabstractThis paper presents an analysis of recently adopted EU policies on fragile states. While the European Union has incorporated governance issues into its strategies for fragile states, its approach to governance has a highly technocratic character, with a strong emphasis on public sector r

  20. Transport of fragile X mental retardation protein via granules in neurites of PC12 cells

    NARCIS (Netherlands)

    Y. de Diego Otero (Yolanda); E.A.W.F.M. Severijnen (Lies-Anne); W.A. van Cappellen (Gert); M. Schrier (Mariëtte); R. Willemsen (Rob); B.A. Oostra (Ben)

    2002-01-01

    textabstractLack of fragile X mental retardation protein (FMRP) causes fragile X syndrome, a common form of inherited mental retardation. FMRP is an RNA binding protein thought to be involved in translation efficiency and/or trafficking of certain mRNAs. Recently, a subset of mRNAs

  1. The fragile X-associated tremor ataxia syndrome (FXTAS) in Indonesia

    NARCIS (Netherlands)

    Winarni, T.I.; Mundhofir, F.E.P.; Ediati, A.; Belladona, M.; Nillesen, W.M.; Yntema, H.G.; Hamel, B.C.J.; Faradz, S.M.H.; Hagerman, R.J.

    2013-01-01

    Fragile X-associated disorders caused by the premutation of the FMR1 gene, includes the fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS affects more than 40% of premutation males over the age of 50 and 75% over the age of 80. FMR1 molecular analysis was done using PCR and confirmed by Sou

  2. Mathematics Learning Disabilities in Girls with Fragile X or Turner Syndrome during Late Elementary School

    Science.gov (United States)

    Murphy, Melissa M.; Mazzocco, Michele M. M.

    2008-01-01

    The present study focuses on math and related skills among 32 girls with fragile X (n = 14) or Turner (n = 18) syndrome during late elementary school. Performance in each syndrome group was assessed relative to Full Scale IQ-matched comparison groups of girls from the general population (n = 32 and n = 89 for fragile X syndrome and Turner…

  3. Adaptive Skills, Behavior Problems, and Parenting Stress in Mothers of Boys with Fragile X Syndrome

    Science.gov (United States)

    Sarimski, Klaus

    2010-01-01

    The relationship of temperament, atypical behaviors, and adaptive behavior of young boys with Fragile X syndrome on mothers' parenting stress was analyzed. Twenty-six boys with Fragile X syndrome (30-88 months of age) participated. The overall development of the participants was significantly delayed with a specific profile of adaptive behaviors…

  4. Analysis of base isolation and energy dissipation systems for NPP structures using fragility models

    Energy Technology Data Exchange (ETDEWEB)

    Vulpe, A. [Technical Univ. of Iasi (Romania). Dept. of Structural Mechanics; Carausu, A. [Technical Univ. of Iasi (Romania). Dept. od Mathematics

    1995-12-31

    Some extensions of analytical models for base isolation and energy dissipation systems, involving fragility models, are presented. The equation of motion is extended with a term corresponding to Energy Dissipation effect, and the fragility of IEDS (Isolation and Energy Dissipations Systems) is evaluated using a bilinear regression line. (author). 11 refs., 2 figs.

  5. Cerebral protein synthesis in a knockin mouse model of the fragile X premutation

    NARCIS (Netherlands)

    M. Qin (Mei); T. Huang (Tianjian); Z. Liu (Zhonghua); M. Kader (Michael); T. Burlin (Thomas); Z. Xia (Zengyan); Z. Zeidler (Zachary); R.K. Hukema (Renate); C.B. Smith (Carolyn B.)

    2014-01-01

    textabstractThe (CGG)n-repeat in the 5’-untransiated region of the fragile X mental retardation gene (FMRi) gene is polymorphic and may become unstable on transmission to the next generation. In fragile X syndrome, CGG repeat lengths exceed 200, resulting in silencing of FMRi and absence of its prot

  6. An Investigation of Narrative Ability in Boys with Autism and Fragile X Syndrome

    Science.gov (United States)

    Hogan-Brown, Abigail L.; Losh, Molly; Martin, Gary E.; Mueffelmann, Deborah J.

    2013-01-01

    Whereas pragmatic language difficulties are characteristic of both autism and Fragile X syndrome, it is unclear whether such deficits are qualitatively similar or whether certain skills are differentially affected. This study compared narrative competence in boys with autism, Fragile X syndrome, Down syndrome, and typical development. Results…

  7. Medium-Range Order Structure and Fragility of Superheated Melts of Amorphous CuHf Alloys

    Institute of Scientific and Technical Information of China (English)

    BIAN Xiu-Fang; SUN Bao-An; HU Li-Na

    2006-01-01

    @@ The structural factors of amorphous CuHf alloys at different temperatures are determined by using a high temperature x-ray diffractometer. It is found that not only the short-range order structure but also the medium-range order structure exists in amorphous CuHf alloys. The dynamic viscosities of CuHf alloy melts are measured by a torsional oscillation viscometer. The fragility of superheated melts of CuHf alloys is calculated based on the viscosity data. The experimental results show that the glass-forming ability of the CuHf alloys is closely related to the fragility of their superheated melt. The relationship between the medium-range order structures and the fragility of superheated melts has also been established in amorphous CuHf alloys. In contrast to the fragility of supercooled liquids, the fragility of superheated liquids promises a better approach to reflecting the dynamics of glass forming liquids.

  8. Robust and fragile Werner states in the collective dephasing Robust and fragile Werner states in the collective dephasing

    CERN Document Server

    Li, S B; Li, S B; Xu, J B; Li, Shang-Bin; Xu, Jing-Bo; Li, Shang-Bin; Xu, Jing-Bo

    2005-01-01

    We investigate the concurrence and Bell violation of the Werner or Werner-like states in the presence of collective dephasing. It is shown that the Werner and certain kinds of Werner-like states are robust against the collective dephasing, and some kinds of Werner-like states is fragile and becomes completely disentangled in a finite-time. The threshold time of complete disentanglement of the Werner state is given. The influence of external driving field on the finite-time disentanglement of Werner states is discussed. Finally, we present a simple method to control the stationary state entanglement of two qubits. We investigate the concurrence and Bell violation of the Werner or Werner-like states in the presence of collective dephasing. It is shown that the Werner and certain kinds of Werner-like states are robust against the collective dephasing, and some kinds of Werner-like states is fragile and becomes completely disentangled in a finite-time. The threshold time of complete disentanglement of the Werner ...

  9. A System To Generate Chromosomal Mutations in Lactococcus lactis Which Allows Fast Analysis of Targeted Genes

    NARCIS (Netherlands)

    Law, Jean; Buist, Girbe; Haandrikman, Alfred; Kok, Jan; Venema, Gerhardus; Leenhouts, Kees

    1995-01-01

    A system for generating chromosomal insertions in lactococci is described. It is based on the conditional replication of lactococcal pWV01-derived Ori+ RepA- vector pORI19, containing lacZα and the multiple cloning site of pUC19. Chromosomal AluI fragments of Lactococcus lactis were cloned in pORI19

  10. Resolution of Multimeric Forms of Circular Plasmids and Chromosomes.

    Science.gov (United States)

    Crozat, Estelle; Fournes, Florian; Cornet, François; Hallet, Bernard; Rousseau, Philippe

    2014-10-01

    One of the disadvantages of circular plasmids and chromosomes is their high sensitivity to rearrangements caused by homologous recombination. Odd numbers of crossing-over occurring during or after replication of a circular replicon result in the formation of a dimeric molecule in which the two copies of the replicon are fused. If they are not converted back to monomers, the dimers of replicons may fail to correctly segregate at the time of cell division. Resolution of multimeric forms of circular plasmids and chromosomes is mediated by site-specific recombination, and the enzymes that catalyze this type of reaction fall into two families of proteins: the serine and tyrosine recombinase families. Here we give an overview of the variety of site-specific resolution systems found on circular plasmids and chromosomes.

  11. 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.

  12. B chromosome and NORs polymorphism in Callichthys callichthys (Linnaeus, 1758 (Siluriformes: Callichthyidae from upper Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    Jocicléia Thums Konerat

    2014-09-01

    Full Text Available B chromosomes are extra chromosomes from the normal chromosomal set, found in different organisms, highlighting their presence on the group of fishes. Callichthys callichthys from the upper Paraná River has a diploid number of 56 chromosomes (26 m-sm + 30 st-a for both sexes, with the presence of a sporadically acrocentric B chromosome. Moreover, one individual presented a diploid number of 57 chromosomes, with the presence of a morphologically ill-defined acrocentric B chromosome in all analyzed cells. The physical mapping of 5S and 18S rDNA shows multiple 5S rDNA sites and only one pair of chromosomes with 18S sites in C. callichthys, except for two individuals. These two individuals presented a third chromosome bearing NORs (Ag-staining and 18S rDNA where 5S and 18S rDNA genes are syntenic, differing only in position. The dispersion of the 18S rDNA genes from the main st-achromosome pair 25 to one of the chromosomes from the m-sm pair 4 would have originated two variant individuals, one of which with the ill-defined acrocentric B chromosome. Mechanisms to justify the suggested hypothesis about this B chromosome origin are discussed in the present study.

  13. Molecular analyses of neurogenic defects in a human pluripotent stem cell model of fragile X syndrome.

    Science.gov (United States)

    Boland, Michael J; Nazor, Kristopher L; Tran, Ha T; Szücs, Attila; Lynch, Candace L; Paredes, Ryder; Tassone, Flora; Sanna, Pietro Paolo; Hagerman, Randi J; Loring, Jeanne F

    2017-01-29

    New research suggests that common pathways are altered in many neurodevelopmental disorders including autism spectrum disorder; however, little is known about early molecular events that contribute to the pathology of these diseases. The study of monogenic, neurodevelopmental disorders with a high incidence of autistic behaviours, such as fragile X syndrome, has the potential to identify genes and pathways that are dysregulated in autism spectrum disorder as well as fragile X syndrome. In vitro generation of human disease-relevant cell types provides the ability to investigate aspects of disease that are impossible to study in patients or animal models. Differentiation of human pluripotent stem cells recapitulates development of the neocortex, an area affected in both fragile X syndrome and autism spectrum disorder. We have generated induced human pluripotent stem cells from several individuals clinically diagnosed with fragile X syndrome and autism spectrum disorder. When differentiated to dorsal forebrain cell fates, our fragile X syndrome human pluripotent stem cell lines exhibited reproducible aberrant neurogenic phenotypes. Using global gene expression and DNA methylation profiling, we have analysed the early stages of neurogenesis in fragile X syndrome human pluripotent stem cells. We discovered aberrant DNA methylation patterns at specific genomic regions in fragile X syndrome cells, and identified dysregulated gene- and network-level correlates of fragile X syndrome that are associated with developmental signalling, cell migration, and neuronal maturation. Integration of our gene expression and epigenetic analysis identified altered epigenetic-mediated transcriptional regulation of a distinct set of genes in fragile X syndrome. These fragile X syndrome-aberrant networks are significantly enriched for genes associated with autism spectrum disorder, giving support to the idea that underlying similarities exist among these neurodevelopmental diseases.

  14. FtsK-dependent dimer resolution on multiple chromosomes in the pathogen Vibrio cholerae.

    Directory of Open Access Journals (Sweden)

    Marie-Eve Val

    Full Text Available Unlike most bacteria, Vibrio cholerae harbors two distinct, nonhomologous circular chromosomes (chromosome I and II. Many features of chromosome II are plasmid-like, which raised questions concerning its chromosomal nature. Plasmid replication and segregation are generally not coordinated with the bacterial cell cycle, further calling into question the mechanisms ensuring the synchronous management of chromosome I and II. Maintenance of circular replicons requires the resolution of dimers created by homologous recombination events. In Escherichia coli, chromosome dimers are resolved by the addition of a crossover at a specific site, dif, by two tyrosine recombinases, XerC and XerD. The process is coordinated with cell division through the activity of a DNA translocase, FtsK. Many E. coli plasmids also use XerCD for dimer resolution. However, the process is FtsK-independent. The two chromosomes of the V. cholerae N16961 strain carry divergent dimer resolution sites, dif1 and dif2. Here, we show that V. cholerae FtsK controls the addition of a crossover at dif1 and dif2 by a common pair of Xer recombinases. In addition, we show that specific DNA motifs dictate its orientation of translocation, the distribution of these motifs on chromosome I and chromosome II supporting the idea that FtsK translocation serves to bring together the resolution sites carried by a dimer at the time of cell division. Taken together, these results suggest that the same FtsK-dependent mechanism coordinates dimer resolution with cell division for each of the two V. cholerae chromosomes. Chromosome II dimer resolution thus stands as a bona fide chromosomal process.

  15. Microdissection and molecular manipulation of single chromosomes in woody fruit trees with small chromosomes using pomelo (Citrus grandis) as a model. II. Cloning of resistance gene analogs from single chromosomes.

    Science.gov (United States)

    Huang, D; Wu, W; Lu, L

    2004-05-01

    Amplification of resistance gene analogs (RGAs) is both a useful method for acquiring DNA markers closely linked to disease resistance (R) genes and a potential approach for the rapid cloning of R genes in plants. However, the screening of target sequences from among the numerous amplified RGAs can be very laborious. The amplification of RGAs from specific chromosomes could greatly reduce the number of RGAs to be screened and, consequently, speed up the identification of target RGAs. We have developed two methods for amplifying RGAs from single chromosomes. Method 1 uses products of Sau3A linker adaptor-mediated PCR (LAM-PCR) from a single chromosome as the templates for RGA amplification, while Method 2 directly uses a single chromosomal DNA molecule as the template. Using a pair of degenerate primers designed on the basis of the conserved nucleotide-binding-site motifs in many R genes, RGAs were successfully amplified from single chromosomes of pomelo using both these methods. Sequencing and cluster analysis of RGA clones obtained from single chromosomes revealed the number, type and organization of R-gene clusters on the chromosomes. We suggest that Method 1 is suitable for analyzing chromosomes that are unidentifiable under a microscope, while Method 2 is more appropriate when chromosomes can be clearly identified.

  16. Genetics Home Reference: Y chromosome infertility

    Science.gov (United States)

    ... Home Health Conditions Y chromosome infertility Y chromosome infertility Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Y chromosome infertility is a condition that affects the production of ...

  17. Higher order structure of chromosomes.

    Science.gov (United States)

    Okada, T A; Comings, D E

    1979-04-01

    Isolated Chinese hamster metaphase chromosomes were resuspended in 4 M ammonium acetate and spread on a surface of distilled water or 0.15 to 0.5 M ammonium acetate. The DNA was released in the form of a regular series of rosettes connected by interrossette DNA. The mean length of the rosette DNA was 14 micron, similar to the mean length of 10 micron for chromomere DNA of Drosophila polytene chromosomes. The mean interrosette DNA was 4.2 micron. SDS gel electrophoresis of the chromosomal nonhistone proteins showed them to be very similar to nuclear nonhistone proteins except for the presence of more actin and tubulin. Nuclear matrix proteins were present in the chromosomes and may play a role in forming the rosettes. Evidence that the rosette pattern is artifactual versus the possibility that it represents a real organizational substructure of the chromosomes is reviewed.

  18. Bacterial chromosome organization and segregation.

    Science.gov (United States)

    Badrinarayanan, Anjana; Le, Tung B K; Laub, Michael T

    2015-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly 1 mm long, approximately 1,000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length scales, highlighting the functions of various DNA-binding proteins and the impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation.

  19. Chromosome choreography: the meiotic ballet.

    Science.gov (United States)

    Page, Scott L; Hawley, R Scott

    2003-08-08

    The separation of homologous chromosomes during meiosis in eukaryotes is the physical basis of Mendelian inheritance. The core of the meiotic process is a specialized nuclear division (meiosis I) in which homologs pair with each other, recombine, and then segregate from each other. The processes of chromosome alignment and pairing allow for homolog recognition. Reciprocal meiotic recombination ensures meiotic chromosome segregation by converting sister chromatid cohesion into mechanisms that hold homologous chromosomes together. Finally, the ability of sister kinetochores to orient to a single pole at metaphase I allows the separation of homologs to two different daughter cells. Failures to properly accomplish this elegant chromosome dance result in aneuploidy, a major cause of miscarriage and birth defects in human beings.

  20. 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.

  1. I’m incredible—or am I? : On the socialization of fragile self-views in children

    NARCIS (Netherlands)

    Brummelman, E.

    2015-01-01

    I’m incredible—or am I? This is a recurring and daunting question for children with fragile self-views, whose feelings of self-worth crumble in the face of setbacks. What are the origins of children’s fragile self-views, and how can interventions reduce the fragility of children’s self-views? The cu

  2. A high-resolution interval map of the q21 region of the human X chromosome

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, C.; Monaco, A.P. [ICRF Laboratories, Oxford (United Kingdom)] [and others; Arnould, C. [Laboratoire de Genetique Humaine, Vandoeuvre-les-Nancy (France)] [and others

    1995-06-10

    In a previous study, we have developed a panel of chromosomal rearrangements for the physical mapping of the q13-q21 region of the human X chromosome. Here, we report the physical localization of 36 additional polymorphic markers by polymerase chain reaction analysis. The high density of chromosomal breakpoints in Xq21 allows us to map 58 DNA loci in 22 intervals. As a result, this segment of the X chromosome is saturated with approximately three sequence tagged sites per megabase of DNA, which will facilitate the construction of a YAC contig of this region. 26 refs., 1 fig., 1 tab.

  3. Comparative Sex Chromosome Genomics in Snakes: Differentiation, Evolutionary Strata, and Lack of Global Dosage Compensation

    Science.gov (United States)

    Zektser, Yulia; Mahajan, Shivani; Bachtrog, Doris

    2013-01-01

    Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females). Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae), but completely heteromorphic sex chromosomes in both garter snakes (Colubridae) and pygmy rattlesnake (Viperidae). Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases). This demonstrates that mutation rates are male-biased in snakes (male-driven evolution), but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex chromosomes

  4. Comparative sex chromosome genomics in snakes: differentiation, evolutionary strata, and lack of global dosage compensation.

    Directory of Open Access Journals (Sweden)

    Beatriz Vicoso

    Full Text Available Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females. Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae, but completely heteromorphic sex chromosomes in both garter snakes (Colubridae and pygmy rattlesnake (Viperidae. Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases. This demonstrates that mutation rates are male-biased in snakes (male-driven evolution, but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex

  5. A case of segmental paternal isodisomy of chromosome 14.

    Science.gov (United States)

    Coveler, Karen J; Yang, Sam P; Sutton, ReidV; Milstein, Jay M; Wu, Yuan-Qing; Bois, Knox-Du; Beischel, Linda S; Johnson, John P; Shaffer, Lisa G

    2002-03-01

    Uniparental disomy of chromosome 14 (UPD 14) results in one of two distinct abnormal phenotypes, depending upon the parent of origin. This discordance may result from the reciprocal over-expression and/or under-expression of one or more imprinted genes. We report a case of segmental paternal isodisomy for chromosome 14 with features similar to those reported in other paternal disomy 14 cases. Microsatellite marker analysis revealed an apparent somatic recombination event in 14q12 leading to proximal biparental inheritance, but segmental paternal uniparental isodisomy distal to this site. Analysis of monochromosomal somatic cell hybrids containing either the paternally inherited or the maternally inherited chromosome 14 revealed no deletion of the maternally inherited chromosome 14 and demonstrated the presence of paternal sequences from D14S121 to the telomere on both chromosomes 14. Thus, the patient has paternal isodisomy for 14q12-14qter. Because the patient shows most of the features associated with paternal disomy 14, this supports the presence of the imprinted domain(s) distal to 14q12 and suggests that the proximal region of chromosome 14 does not contain imprinted genes that contribute significantly to the paternal UPD 14 phenotype.

  6. Effect of chromosome tethering on nuclear organization in yeast.

    Directory of Open Access Journals (Sweden)

    Barış Avşaroğlu

    Full Text Available Interphase chromosomes in Saccharomyces cerevisiae are tethered to the nuclear envelope at their telomeres and to the spindle pole body (SPB at their centromeres. Using a polymer model of yeast chromosomes that includes these interactions, we show theoretically that telomere attachment to the nuclear envelope is a major determinant of gene positioning within the nucleus only for genes within 10 kb of the telomeres. We test this prediction by measuring the distance between the SPB and the silent mating locus (HML on chromosome III in wild-type and mutant yeast strains that contain altered chromosome-tethering interactions. In wild-type yeast cells we find that disruption of the telomere tether does not dramatically change the position of HML with respect to the SPB, in agreement with theoretical predictions. Alternatively, using a mutant strain with a synthetic tether that localizes an HML-proximal site to the nuclear envelope, we find a significant change in the SPB-HML distance, again as predicted by theory. Our study quantifies the importance of tethering at telomeres on the organization of interphase chromosomes in yeast, which has been shown to play a significant role in determining chromosome function such as gene expression and recombination.

  7. The prevalence of Y chromosome microdeletions in Pakistani infertile men

    Directory of Open Access Journals (Sweden)

    Rubina Tabassum Siddiqui

    2013-01-01

    Full Text Available Background: Microdeletions of the azoospermia factor locus of the long arm of Y chromosome are an etiological factor of severe oligozoospermia or azoospermia. Objective: The aim of this study was to investigate the prevalence of Y-chromosome microdeletions in AZF region and their role in infertility in Pakistani population. Materials and Methods: The type of deletions in AZF locus were detected in infertile men (n=113 and the association of Y chromosome microdeletions with male infertility was assessed by including men (50 with normal karyotype and having children. Y chromosome microdeletions were detected by multiplex PCR using 10 sequence tagged sites namely sY81, sY130, sY141, sY142, sY155, sY157, sY160, sY182, sY231, and sY202 that covered all three regions of AZF. Results: Individuals with severe oligozoospermia showed 2.86% deletion frequency in AZFc region as compared to azoospermic males (5.5%. Conclusion: The results of our study showed that deletions in Y chromosome are not playing major part in male infertility. Moreover, multiplex-PCR strategy might preferably be employed for the detection of Y chromosome microdeletions allied to male infertility.

  8. Uptake and Diagnostic Yield of Chromosomal Microarray in an Australian Child Development Clinic

    Directory of Open Access Journals (Sweden)

    Dylan Mordaunt

    2014-05-01

    Full Text Available Autism is an etiologically heterogeneous developmental disorder for which the range of genetic investigations has expanded considerably over the past decade. Introduction of chromosomal microarray (CMA to clinical practice has expanded the range of conditions which pediatricians are able to detect. This study reviewed the utilization, yield and cost of genetic investigations in a sample of children with pervasive developmental disorders (PDD in an Australian metropolitan child development service. Six hundred and ninety eight patients with PDD were identified from the clinic population. One hundred and ten (15.7% of the clinic population had undergone investigation with chromosomal microarray, 140 (20.0% with karyotype (KT, and 167 (23.9% with Fragile X testing (FRGX. Twelve (10.9% CMA findings were reported, of which seven (6.3% were felt to be the likely cause of the child’s clinical features. Five (3.5% KT findings were reported, of which four (2.9% were felt to be the likely cause of the child’s clinical features. Two patients (1.2% were identified with Fragile X expansions. One fifth of the clinic’s recent PDD population had undergone testing with CMA. CMA appears to have increased the diagnostic yield of the genetic investigation of autism, in line with internationally reported levels. Number needed to test (NNT and cost per incremental diagnosis, were also in line with internationally reported levels.

  9. Chromatid Painting for Chromosomal Inversion Detection Project

    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...

  10. CHROMOSOMAL MAPPING IN STRAINS OF STAPHYLOCOCCUS AUREUS,

    Science.gov (United States)

    STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).

  11. Chromatid Painting for Chromosomal Inversion Detection Project

    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...

  12. 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

  13. Skin fragility syndrome in a cat with multicentric follicular lymphoma.

    Science.gov (United States)

    Crosaz, Odile; Vilaplana-Grosso, Federico; Alleaume, Charline; Cordonnier, Nathalie; Bedu-Leperlier, Anne-Sophie; Marignac, Geneviève; Hubert, Blaise; Rosenberg, Dan

    2013-10-01

    An 11-year-old, spayed female domestic shorthair cat was presented for a right flank wound. On clinical examination, a single non-painful skin tear lesion with irregular edges was detected. During the examination, star-shaped cigarette paper-like skin lesions appeared spontaneously. An abdominal mass was also palpated. Feline skin fragility syndrome (FSFS) was suspected and a multicentric lymphoma was diagnosed by fine needle aspiration. The cat's condition declined and it died spontaneously. Post-mortem examination confirmed the diagnosis of lymphoma. Neoplastic lymphocytes were not observed in the skin. Histological analysis of the skin was consistent with the morphological aspects of FSFS. A possible direct link between the two conditions remains a matter of speculation, but this case report provides the first description of FSFS associated with multicentric follicular lymphoma. Thus, multicentric follicular lymphoma should be considered as a differential diagnosis in cats presenting with FSFS.

  14. International Transmission of Shocks and Fragility of a Bank Network

    CERN Document Server

    Feng, Xiaobing; Kim, Beom Jun

    2014-01-01

    The weighted and directed network of countries based on the number of overseas banks is analyzed in terms of its fragility to the banking crisis of one country. We use two different models to describe transmission of shocks, one local and the other global. Depending on the original source of the crisis, the overall size of crisis impacts is found to differ country by country. For the two-step local spreading model, it is revealed that the scale of the first impact is determined by the out-strength, the total number of overseas branches of the country at the origin of the crisis, while the second impact becomes more serious if the in-strength at the origin is increased. For the global spreading model, some countries named "triggers" are found to play important roles in shock transmission, and the importance of the feed-forward-loop mechanism is pointed out. We also discuss practical policy implications of the present work.

  15. Cyclical Cohabitation Among Unmarried Parents in Fragile Families.

    Science.gov (United States)

    Nepomnyaschy, Lenna; Teitler, Julien

    2013-10-01

    Building on past research suggesting that cohabitation is an ambiguous family form, the authors examined an understudied residential pattern among unmarried parents: cyclical cohabitation, in which parents have multiple cohabitation spells with each other. Using 9 years of panel data from the Fragile Families and Child Wellbeing Study (N = 2,084), they found that 10% of all parents with nonmarital births, and nearly a quarter of those living together when the child is 9 years old, are cyclical cohabitors. Cyclically cohabiting mothers reported more material hardships than mothers in most other relationship patterns but also reported more father involvement with children. On all measures of child well-being, except grade retention, children of cyclically cohabiting parents fared no worse than children of stably cohabiting biological parents and did not differ significantly from any other group.

  16. Eastern Seaboard Electric Grid Fragility Maps Supporting Persistent Availability

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Kimberly A [ORNL; Weigand, Gilbert G [ORNL; Fernandez, Steven J [ORNL

    2012-11-01

    Persistently available power transmission can be disrupted by weather causing power outages with economic and social consequences. This research investigated the effects on the national power grid from a specific weather event, Hurricane Irene, that caused approximately 5.7 million customer power outages along the Eastern Seaboard in August of 2011. The objective was to describe the geographic differences in the grid s vulnerability to these events. Individual factors, such as wind speed or precipitation, were correlated with the number of outages to determine the greatest mechanism of power failure in hopes of strengthening the future power grid. The resulting fragility maps not only depicted 18 counties that were less robust than the design-standard robustness model and three counties that were more robust, but also drew new damage contours with correlated wind speeds and county features.

  17. Seismic fragility test of a 6-inch diameter pipe system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W. P.; Onesto, A. T.; DeVita, V.

    1987-02-01

    This report contains the test results and assessments of seismic fragility tests performed on a 6-inch diameter piping system. The test was funded by the US Nuclear Regulatory Commission (NRC) and conducted by ETEC. The objective of the test was to investigate the ability of a representative nuclear piping system to withstand high level dynamic seismic and other loadings. Levels of loadings achieved during seismic testing were 20 to 30 times larger than normal elastic design evaluations to ASME Level D limits would permit. Based on failure data obtained during seismic and other dynamic testing, it was concluded that nuclear piping systems are inherently able to withstand much larger dynamic seismic loadings than permitted by current design practice criteria or predicted by the probabilistic risk assessment (PRA) methods and several proposed nonlinear methods of failure analysis.

  18. Fragile Watermarking for Image Authentication Using the Characteristic of SVD

    Directory of Open Access Journals (Sweden)

    Heng Zhang

    2017-02-01

    Full Text Available Digital image authentication has become a hot topic in the last few years. In this paper, a pixel-based fragile watermarking method is presented for image tamper identification and localization. By analyzing the left and right singular matrices of SVD, it is found that the matrix product between the first column of the left singular matrix and the transposition of the first column in the right singular matrix is closely related to the image texture features. Based on this characteristic, a binary watermark consisting of image texture information is generated and inserted into the least significant bit (LSB of the original host image. To improve the security of the presented algorithm, the Arnold transform is applied twice in the watermark embedding process. Experimental results indicate that the proposed watermarking algorithm has high security and perceptual invisibility. Moreover, it can detect and locate the tampered region effectively for various malicious attacks.

  19. Brief Report: Autism Symptoms in Infants with Fragile X Syndrome.

    Science.gov (United States)

    Roberts, Jane E; Tonnsen, Bridgette L; McCary, Lindsay M; Caravella, Kelly E; Shinkareva, Svetlana V

    2016-12-01

    Fragile X syndrome (FXS) is the most common known genetic cause of autism spectrum disorder (ASD). Although 50-75 % of children with FXS meet ASD criteria, no studies have compared ASD symptoms in infants with FXS versus other high risk groups, such as siblings of children with ASD (ASIBs). Using the Autism Observation Scale for Infants, our findings indicate that 53 % of 12-month infants with FXS fall in the "at risk" category compared to 17 and 6 % for age-matched ASIBs and controls, respectively. Elevated atypical motor behaviors were associated with elevated risk for FXS. Cross-syndrome comparisons are essential to understanding the heterogeneity of ASD and identifying candidate markers that will facilitate differential diagnosis of ASD in genetic disorders such as FXS.

  20. Why Stay Engaged with a State Deemed Fragile?

    DEFF Research Database (Denmark)

    Andersson, Magnus; Bae, Jinsun

    the expectation of gains, the convenience of repeating the work and the logic of appropriateness. This case expands our understanding of engagement that is often understood to a great degree as a rationalist affair between the engaging and target states. It also affirms the usefulness of constructivist IR......Based on the constructivist international relations (IR) approach, the authors study Sweden’s engagement with the DPRK as a unique case to understand motivations for engaging in a so-called fragile state. Besides having its embassy in Pyongyang and serving as a protecting power for the U.S., Sweden...... approach in accounting for today’s engagement practices involving more stakeholders and less strict cost-benefit calculation....

  1. Identification of the fragile X syndrome: phenotype and educational approaches

    Directory of Open Access Journals (Sweden)

    Begoña Medina Gómez

    2014-12-01

    Full Text Available Researchers confirm that fragile X syndrome is the leading cause of hereditary intellectual disability, but it is still largely unknown by educational professionals, health professionals and social service workers. An early detection could avoid transmission of the genetic disorder and would enable the establishment of the most appropriate interventions for each person. Great progress has been made over the last years in the understanding of the neurodevelopmental disorder. In this article, an extensive review about the most relevant studies and contributions that have been made so far concerning its molecular, brain, cognitive and conceptual interactions, the tools to sift in order to detect possible affected people, and also some tips on interventions. Nevertheless there should be continued progress in order to improve the assessment and the assistance in each particular case.

  2. High Pressure Brillouin Scattering in the Fragile Glass Former Cumene

    Science.gov (United States)

    Ransom, Tim; Oliver, William

    2012-02-01

    In recent years full-spectrum analysis in light-scattering has been utilized to explore the liquid-glass transition at variable temperature and ambient pressure. In this study we present temperature- and pressure-dependent Brillouin scattering results for the fragile glass-former cumene. Both equal-angle forward scattering and depolarized backscattering geometries are used, and high pressures are attained by the use of a diamond anvil cell mounted in a custom temperature-controlled housing. Opening up the variable pressure regime to full-spectrum analysis will allow more stringent tests of mode-coupling theory as well as greater insight into the behavior of glass-forming systems.

  3. Systematic review of pharmacological treatments in fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Tejada Maria-Isabel

    2009-10-01

    Full Text Available Abstract Background Fragile X syndrome (FXS is considered the most common cause of inherited mental retardation. Affected people have mental impairment that can include Attention Deficit and/or Hyperactivity Disorder (ADHD, autism disorder, and speech and behavioural disorders. Several pharmacological interventions have been proposed to treat those impairments. Methods Systematic review of the literature and summary of the evidence from clinical controlled trials that compared at least one pharmacological treatment with placebo or other treatment in individuals with diagnosis of FXS syndrome and assessed the efficacy and/or safety of the treatments. Studies were identified by a search of PubMed, EMBASE and the Cochrane Databases using the terms fragile X and treatment. Risk of bias of the studies was assessed by using the Cochrane Collaboration criteria. Results The search identified 276 potential articles and 14 studies satisfied inclusion criteria. Of these, 10 studies on folic acid (9 with crossover design, only 1 of them with good methodological quality and low risk of bias did not find in general significant improvements. A small sample size trial assessed dextroamphetamine and methylphenidate in patients with an additional diagnosis of ADHD and found some improvements in those taking methylphenidate, but the length of follow-up was too short. Two studies on L-acetylcarnitine, showed positive effects and no side effects in patients with an additional diagnosis of ADHD. Finally, one study on patients with an additional diagnosis of autism assessed ampakine compound CX516 and found no significant differences between treatment and placebo. Regarding safety, none of the studies that assessed that area found relevant side effects, but the number of patients included was too small to detect side effects with low incidence. Conclusion Currently there is no robust evidence to support recommendations on pharmacological treatments in patients with

  4. Chromosome mapping of repetitive sequences in four Serrasalmidae species (Characiformes

    Directory of Open Access Journals (Sweden)

    Leila Braga Ribeiro

    2014-01-01

    Full Text Available The Serrasalmidae family is composed of a number of commercially interesting species, mainly in the Amazon region where most of these fishes occur. In the present study, we investigated the genomic organization of the 18S and 5S rDNA and telomeric sequences in mitotic chromosomes of four species from the basal clade of the Serrasalmidae family: Colossoma macropomum, Mylossoma aureum, M. duriventre, and Piaractus mesopotamicus, in order to understand the chromosomal evolution in the family. All the species studied had diploid numbers 2n = 54 and exclusively biarmed chromosomes, but variations of the karyotypic formulas were observed. C-banding resulted in similar patterns among the analyzed species, with heterochromatic blocks mainly present in centromeric regions. The 18S rDNA mapping of C. macropomum and P. mesopotamicus revealed multiple sites of this gene; 5S rDNA sites were detected in two chromosome pairs in all species, although not all of them were homeologs. Hybridization with a telomeric probe revealed signals in the terminal portions of chromosomes in all the species and an interstitial signal was observed in one pair of C. macropomum.

  5. Chromosome 14 translocations in non-Burkitt lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Fukuhara, S.; Rowley, J.D.

    1978-01-01

    Chromosome studies were performed on malignant cells obtained from 27 patients with non-Burkitt lymphomas. A marker chromosome affecting the long arm of No. 14 (14q+) was the single most frequent abnormality and was noted in 17 of these patients. The frequency of the 14q+ marker varied with the type of lymphoma. For patients with malignant lymphoma, histiocytic, the frequency was 5 or 8; for mixed-cell type, 1 of 3; for poorly differentiated lymphocytic, 8 of 8; for well-differentiated lymphocytic, 0.3; for lymphoblastic, 0 of 1; for Hodgkin's disease, 2 of 3; and for mycosis fungoides, 1 of 1. The donor chromosome involved in the 14q translocation was identified in 12 cases; certain chromosomes appeared to be affected more frequently than others. Although the break point was band 14q32 in most cases, the exact location of the receptor site on 14q was not always consistent. The distal part of 14q24 was also involved as a receptor site in at least one translocation. These findings suggest that, in some types of lymphoid malignancy, cells with a 14q translocation have a proliferative advantage over cells with other chromosome rearrangements. The presence of the 14q translocation may be important in the future for the distinction among morphologically different, but functionally comparable, subgroups of lymphoid malignancies.

  6. Condensin-driven remodelling of X chromosome topology during dosage compensation

    Science.gov (United States)

    Crane, Emily; Bian, Qian; McCord, Rachel Patton; Lajoie, Bryan R.; Wheeler, Bayly S.; Ralston, Edward J.; Uzawa, Satoru; Dekker, Job; Meyer, Barbara J.

    2015-07-01

    The three-dimensional organization of a genome plays a critical role in regulating gene expression, yet little is known about the machinery and mechanisms that determine higher-order chromosome structure. Here we perform genome-wide chromosome conformation capture analysis, fluorescent in situ hybridization (FISH), and RNA-seq to obtain comprehensive three-dimensional (3D) maps of the Caenorhabditis elegans genome and to dissect X chromosome dosage compensation, which balances gene expression between XX hermaphrodites and XO males. The dosage compensation complex (DCC), a condensin complex, binds to both hermaphrodite X chromosomes via sequence-specific recruitment elements on X (rex sites) to reduce chromosome-wide gene expression by half. Most DCC condensin subunits also act in other condensin complexes to control the compaction and resolution of all mitotic and meiotic chromosomes. By comparing chromosome structure in wild-type and DCC-defective embryos, we show that the DCC remodels hermaphrodite X chromosomes into a sex-specific spatial conformation distinct from autosomes. Dosage-compensated X chromosomes consist of self-interacting domains (~1 Mb) resembling mammalian topologically associating domains (TADs). TADs on X chromosomes have stronger boundaries and more regular spacing than on autosomes. Many TAD boundaries on X chromosomes coincide with the highest-affinity rex sites and become diminished or lost in DCC-defective mutants, thereby converting the topology of X to a conformation resembling autosomes. rex sites engage in DCC-dependent long-range interactions, with the most frequent interactions occurring between rex sites at DCC-dependent TAD boundaries. These results imply that the DCC reshapes the topology of X chromosomes by forming new TAD boundaries and reinforcing weak boundaries through interactions between its highest-affinity binding sites. As this model predicts, deletion of an endogenous rex site at a DCC-dependent TAD boundary using

  7. Structural comparison of three types of staphylococcal cassette chromosome mec integrated in the chromosome in methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Ito, T; Katayama, Y; Asada, K; Mori, N; Tsutsumimoto, K; Tiensasitorn, C; Hiramatsu, K

    2001-05-01

    The beta-lactam resistance gene mecA of Staphylococcus aureus is carried by a novel mobile genetic element, designated staphylococcal cassette chromosome mec (SCCmec), identified in the chromosome of a Japanese methicillin-resistant S. aureus (MRSA) strain. We now report identification of two additional types of mecA-carrying genetic elements found in the MRSA strains isolated in other countries of the world. There were substantial differences in the size and nucleotide sequences between the elements and the SCCmec. However, new elements shared the chromosomal integration site with the SCCmec. Structural analysis of the new elements revealed that they possessed all of the salient features of the SCCmec: conserved terminal inverted repeats and direct repeats at the integration junction points, conserved genetic organization around the mecA gene, and the presence of cassette chromosome recombinase (ccr) genes responsible for the movements of SCCmec. The elements, therefore, were considered to comprise the SCCmec family of staphylococcal mobile genetic elements together with the previously identified SCCmec. Among 38 epidemic MRSA strains isolated in 20 countries, 34 were shown to possess one of the three typical SCCmec elements on the chromosome. Our findings indicated that there are at least three distinct MRSA clones in the world with different types of SCCmec in their chromosome.

  8. Identification and characterization of a new type of asymmetrical dicentric chromosome derived from a single maternal chromosome 18.

    Science.gov (United States)

    Lin, C C; Li, Y-C; Liu, P-P; Hsieh, L-J; Cheng, Y-M; Teng, R-H; Shi, S-L; Tsai, F-J

    2007-01-01

    Molecular cytogenetic analysis identified a new type of dicentric chromosome involving different breakpoints at 18q in a female fetus. The chromosome anomaly was designated as an asymmetrical pseudoisodicentric chromosome 18, 46,XX,psu dic(18)(pter-->q11.2::q21.3-->pter)mat. A series of BAC clones for 18q11.2 and q21.3 regions were used to identify one breakpoint within the region q11.2 between 19.8 and 21.6 Mb from the telomere of 18p and another breakpoint within q21.3 between 55.4 and 56.9 Mb from the telomere of 18p by FISH analysis. Real-time quantitative PCR and microsatellite analysis further verified that the dicentric chromosome was maternal in origin and resulted from a break-reunion between sister chromatids of a single maternal chromosome. We propose that a loop-type configuration of sister chromatids took place and that the break-reunion occurred at cross sites of the loop to form an asymmetrical isodicentric chromosome during either mitosis or meiosis. In this case, the asymmetrical pseudoisodicentric resulted in an 18pter--> q11.2 duplication and an 18q21.3-->qter deletion, which could have led to certain dysmorphic features of 18q- syndrome in this fetus.

  9. CRISPR-PCS: a powerful new approach to inducing multiple chromosome splitting in Saccharomyces cerevisiae

    Science.gov (United States)

    Sasano, Yu; Nagasawa, Koki; Kaboli, Saeed; Sugiyama, Minetaka; Harashima, Satoshi

    2016-01-01

    PCR-mediated chromosome splitting (PCS) was developed in the yeast Saccharomyces cerevisiae. It is based on homologous recombination and enables division of a chromosome at any point to form two derived and functional chromosomes. However, because of low homologous recombination activity, PCS is limited to a single site at a time, which makes the splitting of multiple loci laborious and time-consuming. Here we have developed a highly efficient and versatile chromosome engineering technology named CRISPR-PCS that integrates PCS with the novel genome editing CRISPR/Cas9 system. This integration allows PCS to utilize induced double strand breaks to activate homologous recombination. CRISPR-PCS enhances the efficiency of chromosome splitting approximately 200-fold and enables generation of simultaneous multiple chromosome splits. We propose that CRISPR-PCS will be a powerful tool for breeding novel yeast strains with desirable traits for specific industrial applications and for investigating genome function. PMID:27530680

  10. 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.

  11. Knob-associated tandem repeats on mitotic chromosomes in maize, Zea diploperennis and their hybrids

    Institute of Scientific and Technical Information of China (English)

    XIONG Zhiyong; GAO Yuan; HE Guanyuan; GU Mingguang; GUO Lequn; SONG Yunchun

    2004-01-01

    Knob-associated tandem repeats, 180-bp repeats and TR-1 elements, together with 45S rDNA were located on mitotic chromosomes of Zea diploperennis (DP),maize inbred line F102 and their hybrid. In DP, knobs on the short arm of chromosomes 1 and 4 and on the long arm of the chromosomes 4 and 5 are composed predominantly of the 180-bp repeats. In addition, 180-bp repeats existed together with TR-1 elements were also detected on the short arm of chromosomes 2 and 5 and on the long arm of the chromosomes 2, 6, 7, 8 and 9. In maize inbred line F102, 180-bp repeats were present in chromosomes 7S and one homologue of chromosomes 8L. TR-1 elements appeared on satellite of chromosome 6 and no detectable hybridization site co-located with 180-bp repeats was observed in maize F102. Polymorphism of size, number, and distribution of 180-bp and TR-1 signals were revealed among different chromosomes in these two species and heteromorphism existed between some homologous chromosomes in the same species.Using these excellent landmarks, the interspecific hybrid of maize and DP were identified. The results suggest that comparative analysis of 180-bp repeats and TR-1 elements may help understand the genome organization and the evolution in Zea.

  12. Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells

    Directory of Open Access Journals (Sweden)

    Hiroshi Sato

    2017-01-01

    Full Text Available Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV. Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.

  13. The rulB gene of plasmid pWW0 is a hotspot for the site-specific insertion of integron-like elements found in the chromosomes of environmental Pseudomonas fluorescens group bacteria.

    Science.gov (United States)

    Rhodes, Glenn; Bosma, Hester; Studholme, David; Arnold, Dawn L; Jackson, Robert W; Pickup, Roger W

    2014-08-01

    The rulAB operon of Pseudomonas spp. confers fitness traits on the host and has been suggested to be a hotspot for insertion of mobile elements that carry avirulence genes. Here, for the first time, we show that rulB on plasmid pWW0 is a hotspot for the active site-specific integration of related integron-like elements (ILEs) found in six environmental pseudomonads (strains FH1-FH6). Integration into rulB on pWW0 occurred at position 6488 generating a 3 bp direct repeat. ILEs from FH1 and FH5 were 9403 bp in length and contained eight open reading frames (ORFs), while the ILE from FH4 was 16 233 bp in length and contained 16 ORFs. In all three ILEs, the first 5.1 kb (containing ORFs 1-4) were structurally conserved and contained three predicted site-specific recombinases/integrases and a tetR homologue. Downstream of these resided ORFs of the 'variable side' with structural and sequence similarity to those encoding survival traits on the fitness enhancing plasmid pGRT1 (ILE(FH1) and ILE(FH5)) and the NR-II virulence region of genomic island PAGI-5 (ILE(FH4)). Collectively, these ILEs share features with the previously described type III protein secretion system effector ILEs and are considered important to host survival and transfer of fitness enhancing and (a)virulence genes between bacteria.

  14. Location of 45S Ribosomal Genes in Mitotic and Meiotic Chromosomes of Buthid Scorpions.

    Science.gov (United States)

    Mattos, Viviane Fagundes; Carvalho, Leonardo Sousa; Cella, Doralice Maria; Schneider, Marielle Cristina

    2014-09-01

    Buthid scorpions exhibit a high variability in diploid number within genera and even within species. Cytogenetically, Buthidae differs from other families of Scorpiones based on its low diploid numbers, holocentric chromosomes, and complex chromosomal chains, which form during meiosis. In this study, we analyzed the distribution of the 45S ribosomal DNA (rDNA) genes in the mitotic and meiotic chromosomes of seven buthid species belonging to the genera Rhopalurus and Tityus with the ultimate goal of elucidating the chromosome organization in these scorpions. The chromosome number ranged from 2n=6 to 2n=28. Despite the high variance in diploid number, all species examined carried their 45S rDNA sites in the terminal region of exactly two chromosomes. Analyses of meiotic cells revealed 45S rDNA clusters in the chromosomal chains of Rhopalurus agamemnon, Tityus bahiensis, Tityus confluens, and Tityus martinpaechi, or in bivalent-like configuration in Rhopalurus rochai, Tityus bahiensis, Tityus confluens, Tityus fasciolatus, and Tityus paraguayensis. In the species examined, the 45S rDNA sites colocalized with constitutive heterochromatin regions. In light of the high chromosome variability and maintenance of number and terminal position of 45S rDNA sites in buthids, the heterochromatin may act to conserve the integrity of the ribosomal genes.

  15. Chromosome segregation in Vibrio cholerae.

    Science.gov (United States)

    Ramachandran, Revathy; Jha, Jyoti; Chattoraj, Dhruba K

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae compare with those in other bacteria, and highlight some of the remaining questions regarding the process of bacterial chromosome segregation.

  16. Scaling up nutrition in fragile and conflict-affected states: the pivotal role of governance.

    Science.gov (United States)

    Taylor, Sebastian A J; Perez-Ferrer, Carolina; Griffiths, Andrew; Brunner, Eric

    2015-02-01

    Acute and chronic undernutrition undermine conditions for health, stability and socioeconomic development across the developing world. Although fragile and conflict-affected states have some of the highest rates of undernutrition globally, their response to the multilateral 'Scaling Up Nutrition' (SUN) initiative in its first two-year period was ambivalent. The purpose of this research was to investigate factors affecting fragile and conflict-affected states' engagement with SUN, and to examine what differentiated those fragile states that joined SUN in its first phase from those that did not. Drawing on global databases (Unicef, World Bank, UNDP), and qualitative country case studies (Afghanistan, the Democratic Republic of Congo, Sierra Leone, Pakistan and Yemen) we used bivariate logistic regressions and principal component analysis to assess social, economic and political factors across 41 fragile states looking for systematic differences between those that had signed up to SUN before March 2013 (n = 16), and those that had not (n = 25). While prevalence of malnutrition, health system functioning and level of citizen empowerment had little or no impact on a fragile state's likelihood of joining SUN, the quality of governance (QOG) strongly predicted accession. SUN-signatory fragile states scored systematically better on the World Bank's Country Policy and Institutional Assessment (CPIA) and the Worldwide Governance Indicators 'effectiveness of government' indices. We conclude that strengthening governance in fragile states may enhance their engagement with initiatives such as SUN, but also (recognising the potential for endogeneity), that the way aid is structured and delivered in fragile states may be an underlying determinant of whether and how governance in such contexts improves. The research demonstrates that more nuanced analysis of conditions within and among countries classed as 'fragile and conflict-affected' is both possible and necessary if aid

  17. Numerous transitions of sex chromosomes in Diptera.

    Science.gov (United States)

    Vicoso, Beatriz; Bachtrog, Doris

    2015-04-01

    Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot), but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes). Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  18. Non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper focuses on the problem of non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems. The controller gain to be designed is assumed to have additive gain variations. Based on multiple-Lyapunov function technique, the design of non-fragile hybrid guaranteed cost controllers is derived to make the corresponding closed-loop system asymptotically stable for all admissible uncertainties. Furthermore, a convex optimization approach with LMIs constraints is introduced to select the optimal non-fragile guaranteed cost controllers. Finally, a simulation example illustrates the effectiveness of the proposed approach.

  19. A Bayesian formulation of seismic fragility analysis of safety related equipment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z-L.; Pandey, M.; Xie, W-C., E-mail: z268wang@uwaterloo.ca, E-mail: mdpandey@uwaterloo.ca, E-mail: xie@uwaterloo.ca [Univ. of Waterloo, Ontario (Canada)

    2013-07-01

    A Bayesian approach to seismic fragility analysis of safety-related equipment is formulated. Unlike treating two sources of uncertainty of in the parameter estimation in two steps separately using the classical statistics, a Bayesian hierarchical model is advocated for interpreting and combining the various uncertainties more clearly in this article. In addition, with the availability of additional earthquake experience data and shaking table test results, a Bayesian approach to updating the fragility model of safety-related equipment is formulated by incorporating acquired failure and survivor evidence. Numerical results show the significance in fragility analysis using the Bayesian approach. (author)

  20. The Role of Chain Length in Nonergodicity Factor and Fragility of Polymers

    DEFF Research Database (Denmark)

    Dalle-Ferrie, Cecile; Niss, Kristine; Sokolov, Alexei

    2010-01-01

    between the fragility of glass-formers and their nonergodicity factor, determined by inelastic X-ray scattering (IXS) in the glass. We extend this molecular liquid study to two model polymers— polystyrene (PS) and polyisobutylene (PIB)—for which we change the molecular weight. Polymers offer...... the opportunity to change the fragility without altering the chemical structure, just by changing the chain length. Thus, we specifically chose PS and PIB because they exhibit opposite dependences of fragility with molecular weight. Our analysis for these two polymers reveals no unique correlation between...

  1. 易损数字水印技术:研究与应用%Fragile Digital Watermarking: Research and Application

    Institute of Scientific and Technical Information of China (English)

    陆唯杰; 陈克非

    2002-01-01

    Recently, digital watermarking techniques for multimedia get fast growth. Digital watermark is some in-formation that will bring no perceptual feeling when embedded in the multimedia data. There are mainly two kind ofwatermark: robust watermark for copyright protection and fragile watermark for data integrity and data authentici-ty. In this paper, we will mainly focus on fragile watermarking. For the purpose of multimedia integrity and authen-ticity protection, we classify current methods into three categories: digital signature techniques, fragile watermarkingtechniques based on Hash function and other fragile digital watermarking techniques. And we discuss each category inthis paper, and especially discuss fragile watermarking in detail. Such a classification will help us understand thefunctions of digital signature and fragile watermarking in data integrity and authenticity protection. And we also dis-cuss some attacks on fragile watermarking and its applications.

  2. Rater reliability of fragile X mutation size estimates: A multilaboratory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, G.S. [Kings County Hospital Center and SUNY/Health Science Center, Brooklyn, NY (United States); Carpenter, N. [Chapman Institute of Medical Genetics, Tulsa, OK (United States); Maddalena, A. [Medical College of Virginia, Richmond, VA (United States)] [and others

    1996-08-09

    Notwithstanding the use of comparable molecular protocols, description and measurement of the fra(X) (fragile X) mutation may vary according to its appearance as a discrete band, smear, multiple bands, or mosaic. Estimation of mutation size may also differ from one laboratory to another. We report on the description of a mutation size estimate for a large sample of individuals tested for the fra(X) pre- or full mutation. Of 63 DNA samples evaluated, 45 were identified previously as fra(X) pre- or full mutations. DNA from 18 unaffected individuals was used as control. Genomic DNA was extracted from peripheral blood, and DNA fragments from each of four laboratories were sent to a single center where Southern blots were prepared and hybridized with the pE5.1 probe. Photographs from autoradiographs were returned to each site, and raters blind to the identity of the specimens were asked to evaluate them. Raters` estimates of mutation size compared favorably with a reference test. Intrarater reliability was good to excellent. Variability in mutation size estimates was comparable across band types. Variability in estimates was moderate, and was significantly correlated with absolute mutation size and band type. 9 refs., 1 fig., 3 tabs.

  3. Repetitive DNA Sequences and Evolution of ZZ/ZW Sex Chromosomes in Characidium (Teleostei: Characiformes).

    Science.gov (United States)

    Scacchetti, Priscilla Cardim; Utsunomia, Ricardo; Pansonato-Alves, José Carlos; da Costa Silva, Guilherme José; Vicari, Marcelo Ricardo; Artoni, Roberto Ferreira; Oliveira, Claudio; Foresti, Fausto

    2015-01-01

    Characidium constitutes an interesting model for cytogenetic studies, since a large degree of karyotype variation has been detected in this group, like the presence/absence of sex and supernumerary chromosomes and variable distribution of repetitive sequences in different species/populations. In this study, we performed a comparative cytogenetic analysis in 13 Characidium species collected at different South American river basins in order to investigate the karyotype diversification in this group. Chromosome analyses involved the karyotype characterization, cytogenetic mapping of repetitive DNA sequences and cross-species chromosome painting using a W-specific probe obtained in a previous study from Characidium gomesi. Our results evidenced a conserved diploid chromosome number of 2n = 50, and almost all the species exhibited homeologous ZZ/ZW sex chromosomes in different stages of differentiation, except C. cf. zebra, C. tenue, C. xavante and C. stigmosum. Notably, some ZZ/ZW sex chromosomes showed 5S and/or 18S rDNA clusters, while no U2 snDNA sites could be detected in the sex chromosomes, being restricted to a single chromosome pair in almost all the analyzed species. In addition, the species Characidium sp. aff. C. vidali showed B chromosomes with an inter-individual variation of 1 to 4 supernumerary chromosomes per cell. Notably, these B chromosomes share sequences with the W-specific probe, providing insights about their origin. Results presented here further confirm the extensive karyotype diversity within Characidium in contrast with a conserved diploid chromosome number. Such chromosome differences seem to constitute a significant reproductive barrier, since several sympatric Characidium species had been described during the last few years and no interespecific hybrids were found.

  4. Repetitive DNA Sequences and Evolution of ZZ/ZW Sex Chromosomes in Characidium (Teleostei: Characiformes.

    Directory of Open Access Journals (Sweden)

    Priscilla Cardim Scacchetti

    Full Text Available Characidium constitutes an interesting model for cytogenetic studies, since a large degree of karyotype variation has been detected in this group, like the presence/absence of sex and supernumerary chromosomes and variable distribution of repetitive sequences in different species/populations. In this study, we performed a comparative cytogenetic analysis in 13 Characidium species collected at different South American river basins in order to investigate the karyotype diversification in this group. Chromosome analyses involved the karyotype characterization, cytogenetic mapping of repetitive DNA sequences and cross-species chromosome painting using a W-specific probe obtained in a previous study from Characidium gomesi. Our results evidenced a conserved diploid chromosome number of 2n = 50, and almost all the species exhibited homeologous ZZ/ZW sex chromosomes in different stages of differentiation, except C. cf. zebra, C. tenue, C. xavante and C. stigmosum. Notably, some ZZ/ZW sex chromosomes showed 5S and/or 18S rDNA clusters, while no U2 snDNA sites could be detected in the sex chromosomes, being restricted to a single chromosome pair in almost all the analyzed species. In addition, the species Characidium sp. aff. C. vidali showed B chromosomes with an inter-individual variation of 1 to 4 supernumerary chromosomes per cell. Notably, these B chromosomes share sequences with the W-specific probe, providing insights about their origin. Results presented here further confirm the extensive karyotype diversity within Characidium in contrast with a conserved diploid chromosome number. Such chromosome differences seem to constitute a significant reproductive barrier, since several sympatric Characidium species had been described during the last few years and no interespecific hybrids were found.

  5. Chromosome Segregation in Vibrio cholerae

    OpenAIRE

    Ramachandran, R.; Jha, J.; Chattoraj, DK

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae com...

  6. Integration of HIV in the Human Genome: Which Sites Are Preferential? A Genetic and Statistical Assessment

    Science.gov (United States)

    Gonçalves, Juliana; Moreira, Elsa; Sequeira, Inês J.; Rodrigues, António S.; Rueff, José; Brás, Aldina

    2016-01-01

    Chromosomal fragile sites (FSs) are loci where gaps and breaks may occur and are preferential integration targets for some viruses, for example, Hepatitis B, Epstein-Barr virus, HPV16, HPV18, and MLV vectors. However, the integration of the human immunodeficiency virus (HIV) in Giemsa bands and in FSs is not yet completely clear. This study aimed to assess the integration preferences of HIV in FSs and in Giemsa bands using an in silico study. HIV integration positions from Jurkat cells were used and two nonparametric tests were applied to compare HIV integration in dark versus light bands and in FS versus non-FS (NFSs). The results show that light bands are preferential targets for integration of HIV-1 in Jurkat cells and also that it integrates with equal intensity in FSs and in NFSs. The data indicates that HIV displays different preferences for FSs compared to other viruses. The aim was to develop and apply an approach to predict the conditions and constraints of HIV insertion in the human genome which seems to adequately complement empirical data. PMID:27294106

  7. B chromosomes and sex in animals.

    Science.gov (United States)

    Camacho, J P M; Schmid, M; Cabrero, J

    2011-01-01

    Supernumerary (B) chromosomes are dispensable elements found in many eukaryote genomes in addition to standard (A) chromosomes. In many respects, B chromosomes resemble sex chromosomes, so that a common ancestry for them has frequently been suggested. For instance, B chromosomes in grasshoppers, and other insects, show a pycnotic cycle of condensation-decondensation during meiosis remarkably similar to that of the X chromosome. In some cases, B chromosome size is even very similar to that of the X chromosome. These resemblances have led to suggest the X as the B ancestor in many cases. In addition, sex chromosome origin from B chromosomes has also been suggested. In this article, we review the existing evidence for both evolutionary pathways, as well as sex differences for B frequency at adult and embryo progeny levels, B chromosome effects or B chromosome transmission. In addition, we review cases found in the literature showing sex-ratio distortion associated with B chromosome presence, the most extreme case being the paternal sex ratio (PSR) chromosomes in some Hymenoptera. We finally analyse the possibility of B chromosome regularisation within the host genome and, as a consequence of it, whether B chromosomes can become regular members of the host genome.

  8. Origin and domestication of papaya Yh chromosome

    Science.gov (United States)

    Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XYh). The hermaphrodite-specific region of the Yh chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previo...

  9. Impaired coenzyme A synthesis in fission yeast causes defective mitosis, quiescence-exit failure, histone hypoacetylation and fragile DNA.

    Science.gov (United States)

    Nakamura, Takahiro; Pluskal, Tomáš; Nakaseko, Yukinobu; Yanagida, Mitsuhiro

    2012-09-01

    Biosynthesis of coenzyme A (CoA) requires a five-step process using pantothenate and cysteine in the fission yeast Schizosaccharomyces pombe. CoA contains a thiol (SH) group, which reacts with carboxylic acid to form thioesters, giving rise to acyl-activated CoAs such as acetyl-CoA. Acetyl-CoA is essential for energy metabolism and protein acetylation, and, in higher eukaryotes, for the production of neurotransmitters. We isolated a novel S. pombe temperature-sensitive strain ppc1-537 mutated in the catalytic region of phosphopantothenoylcysteine synthetase (designated Ppc1), which is essential for CoA synthesis. The mutant becomes auxotrophic to pantothenate at permissive temperature, displaying greatly decreased levels of CoA, acetyl-CoA and histone acetylation. Moreover, ppc1-537 mutant cells failed to restore proliferation from quiescence. Ppc1 is thus the product of a super-housekeeping gene. The ppc1-537 mutant showed combined synthetic lethal defects with five of six histone deacetylase mutants, whereas sir2 deletion exceptionally rescued the ppc1-537 phenotype. In synchronous cultures, ppc1-537 cells can proceed to the S phase, but lose viability during mitosis failing in sister centromere/kinetochore segregation and nuclear division. Additionally, double-strand break repair is defective in the ppc1-537 mutant, producing fragile broken DNA, probably owing to diminished histone acetylation. The CoA-supported metabolism thus controls the state of chromosome DNA.

  10. 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.

  11. Flow karyotyping and sorting of human chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.W.; Lucas, J.; Peters, D.; Pinkel, D.; Trask, B.; van den Engh, G.; Van Dilla, M.A.

    1986-07-16

    Flow cytometry and sorting are becoming increasingly useful as tools for chromosome classfication and for the detection of numerical and structural chromosome aberrations. Chromosomes of a single type can be purified with these tools to facilitate gene mapping or production of chromosome specific recombinant DNA libraries. For analysis of chromosomes with flow cytometry, the chromosomes are extracted from mitotic cells, stained with one or more fluorescent dyes and classified one-by-one according to their dye content(s). Thus, the flow approach is fundamentally different than conventional karyotyping where chromosomes are classified within the context of a metaphase spread. Flow sorting allows purification of chromosomes that can be distinguished flow cytometrically. The authors describe the basic principles of flow cytometric chromosome classification i.e. flow karyotyping, and chromosome sorting and describe several applications. 30 refs., 8 figs.

  12. Comparative chromosome mapping of U2 snRNA and 5S rRNA genes in Gymnotus species (Gymnotiformes, Gymnotidae): evolutionary dynamics and sex chromosome linkage in G . pantanal.

    Science.gov (United States)

    Utsunomia, Ricardo; Scacchetti, Priscilla C; Pansonato-Alves, José C; Oliveira, Claudio; Foresti, Fausto

    2014-01-01

    A comparative mapping of U2 small nuclear RNA (snRNA) and 5S ribosomal RNA (rRNA) genes was performed in 6 Gymnotus species. All species analyzed presented the U2 snDNA organized in conspicuous blocks and not co-located with rRNA genes. In addition, 5 species showed the U2 snDNA located in a single pair of chromosomes, which seems to be a conserved trait in this genus. Conversely, G. pantanal was the only species displaying several terminal signals in different chromosome pairs, including the X1 sex chromosome but not the Y chromosome. This is the first report of U2 snRNA genes in sex chromosomes of fishes. The absence of sites in the Y chromosome of G. pantanal indicates a possible loss of terminal segments of the chromosomes involved in the Y formation.

  13. The Durability and Fragility of Knowledge Infrastructures: Lessons Learned from Astronomy

    CERN Document Server

    Borgman, Christine L; Sands, Ashley E; Golshan, Milena S

    2016-01-01

    Infrastructures are not inherently durable or fragile, yet all are fragile over the long term. Durability requires care and maintenance of individual components and the links between them. Astronomy is an ideal domain in which to study knowledge infrastructures, due to its long history, transparency, and accumulation of observational data over a period of centuries. Research reported here draws upon a long-term study of scientific data practices to ask questions about the durability and fragility of infrastructures for data in astronomy. Methods include interviews, ethnography, and document analysis. As astronomy has become a digital science, the community has invested in shared instruments, data standards, digital archives, metadata and discovery services, and other relatively durable infrastructure components. Several features of data practices in astronomy contribute to the fragility of that infrastructure. These include different archiving practices between ground- and space-based missions, between sky su...

  14. Longer brainstem auditory evoked response latencies of individuals with fragile X syndrome related to sedation.

    Science.gov (United States)

    Miezejeski, C M; Heaney, G; Belser, R; Brown, W T; Jenkins, E C; Sersen, E A

    1997-04-18

    Brainstem auditory evoked response latencies were studies in 75 males (13 with fragile X syndrome, 18 with mental retardation due to other causes, and 44 with no disability). Latency values were obtained for each ear for the positive deflections of waves I (P1), III (P3), and V (P5). Some individuals with mental retardation required sedation. Contrary to previous report, latencies obtained for individuals with fragile X did not differ from those obtained for persons without mental retardation. Persons receiving sedation, whether or not their retardation was due to fragile X, had longer latencies for wave P5 than persons who did not receive sedation. This effect of sedation may also explain the previously reported increased latencies for persons with fragile X.

  15. Financial fragility, sovereign default risk and the limits to commercial bank bail-outs

    NARCIS (Netherlands)

    van Wijnbergen, S.; van der Kwaak, C.

    2013-01-01

    We analyse the poisonous interaction between bank rescues, financial fragility and sovereign debt discounts. In our model balance sheet constrained financial intermediaries finance both capital expenditure of intermediate goods producers and government deficits. The financial intermediaries face the

  16. The Chromosomal Courtship Dance-homolog pairing in early meiosis.

    Science.gov (United States)

    Klutstein, Michael; Cooper, Julia Promisel

    2014-02-01

    The intermingling of genomes that characterizes sexual reproduction requires haploid gametes in which parental homologs have recombined. For this, homologs must pair during meiosis. In a crowded nucleus where sequence homology is obscured by the enormous scale and packaging of the genome, partner alignment is no small task. Here we review the early stages of this process. Chromosomes first establish an initial docking site, usually at telomeres or centromeres. The acquisition of chromosome-specific patterns of binding factors facilitates homolog recognition. Chromosomes are then tethered to the nuclear envelope (NE) and subjected to nuclear movements that 'shake off' inappropriate contacts while consolidating homolog associations. Thereafter, homolog connections are stabilized by building the synaptonemal complex or its equivalent and creating genetic crossovers. Recent perspectives on the roles of these stages will be discussed.

  17. Targeted sequencing of the human X chromosome exome.

    Science.gov (United States)

    Mondal, Kajari; Shetty, Amol Carl; Patel, Viren; Cutler, David J; Zwick, Michael E

    2011-10-01

    We used a RainDance Technologies (RDT) expanded content library to enrich the human X chromosome exome (2.5 Mb) from 26 male samples followed by Illumina sequencing. Our multiplex primer library covered 98.05% of the human X chromosome exome in a single tube with 11,845 different PCR amplicons. Illumina sequencing of 24 male samples showed coverage for 97% of the targeted sequences. Sequence from 2 HapMap samples confirmed missing data rates of 2-3% at sites successfully typed by the HapMap project, with an accuracy of at least ~99.5% as compared to reported HapMap genotypes. Our demonstration that a RDT expanded content library can efficiently enrich and enable the routine sequencing of the human X chromosome exome suggests a wide variety of potential research and clinical applications for this platform.

  18. Activation of proto-oncogenes by disruption of chromosome neighborhoods.

    Science.gov (United States)

    Hnisz, Denes; Weintraub, Abraham S; Day, Daniel S; Valton, Anne-Laure; Bak, Rasmus O; Li, Charles H; Goldmann, Johanna; Lajoie, Bryan R; Fan, Zi Peng; Sigova, Alla A; Reddy, Jessica; Borges-Rivera, Diego; Lee, Tong Ihn; Jaenisch, Rudolf; Porteus, Matthew H; Dekker, Job; Young, Richard A

    2016-03-25

    Oncogenes are activated through well-known chromosomal alterations such as gene fusion, translocation, and focal amplification. In light of recent evidence that the control of key genes depends on chromosome structures called insulated neighborhoods, we investigated whether proto-oncogenes occur within these structures and whether oncogene activation can occur via disruption of insulated neighborhood boundaries in cancer cells. We mapped insulated neighborhoods in T cell acute lymphoblastic leukemia (T-ALL) and found that tumor cell genomes contain recurrent microdeletions that eliminate the boundary sites of insulated neighborhoods containing prominent T-ALL proto-oncogenes. Perturbation of such boundaries in nonmalignant cells was sufficient to activate proto-oncogenes. Mutations affecting chromosome neighborhood boundaries were found in many types of cancer. Thus, oncogene activation can occur via genetic alterations that disrupt insulated neighborhoods in malignant cells.

  19. POF regulates the expression of genes on the fourth chromosome in Drosophila melanogaster by binding to nascent RNA.

    Science.gov (United States)

    Johansson, Anna-Mia; Stenberg, Per; Allgardsson, Anders; Larsson, Jan

    2012-06-01

    In Drosophila, two chromosome-wide compensatory systems have been characterized: the dosage compensation system that acts on the male X chromosome and the chromosome-specific regulation of genes located on the heterochromatic fourth chromosome. Dosage compensation in Drosophila is accomplished by hypertranscription of the single male X chromosome mediated by the male-specific lethal (MSL) complex. The mechanism of this compensation is suggested to involve enhanced transcriptional elongation mediated by the MSL complex, while the mechanism of compensation mediated by the painting of fourth (POF) protein on the fourth chromosome has remained elusive. Here, we show that POF binds to nascent RNA, and this binding is associated with increased transcription output from chromosome 4. We also show that genes located in heterochromatic regions spend less time in transition from the site of transcription to the nuclear envelope. These results provide useful insights into the means by which genes in heterochromatic regions can overcome the repressive influence of their hostile environment.

  20. Drosophila Fragile X Mental Retardation Protein Developmentally Regulates Activity-Dependent Axon Pruning

    OpenAIRE

    Tessier, Charles R.; Broadie, Kendal

    2008-01-01

    Fragile X Syndrome (FraX) is a broad-spectrum neurological disorder with symptoms ranging from hyperexcitability to mental retardation and autism. Loss of the fragile X mental retardation 1 (fmr1) gene product, the mRNA-binding translational regulator FMRP, causes structural over-elaboration of dendritic and axonal processes as well as functional alterations in synaptic plasticity at maturity. It is unclear, however, whether FraX is primarily a disease of development, a disease of plasticity ...